HEIDELBERG MLA150 User Manual

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User Guide

MLA150

Maskless Aligner

MLA150

ii User Guide

Doc. No.: DWL-HI-062 Revision: 1 (July 2016)

MLA150

Table of Contents

User Guide i

Table of Contents

Table of Contents ........................................................................................................... i

List of Figures ............................................................................................................... iv

List of Tables ................................................................................................................ iv

1 Introduction ........................................................................................................... 1

1.1 About this User Guide ............................................................................................. 1

1.2 Contact .................................................................................................................... 2

1.3 Related Documentation ........................................................................................... 3

2 Safety ..................................................................................................................... 5

2.1 Intended Use and Limitations .................................................................................. 5

2.2 Conventions ............................................................................................................ 6

2.3 Laser Safety ............................................................................................................ 6

2.4 Electrical Safety ...................................................................................................... 8

2.5 Other Risks during Operation .................................................................................. 9

2.6 Interlock .................................................................................................................. 9

2.7 Labels ................................................................................................................... 10

3 System Description ............................................................................................. 13

3.1 Lithography Main Unit ........................................................................................... 14

3.1.1 Flowbox ................................................................................................... 14

3.1.2 System Components ............................................................................... 17

3.1.3 Optics System ......................................................................................... 20

3.2 Electronics Rack ................................................................................................... 22

3.3 Orientation of Stage and Design ........................................................................... 23

4 Wizard Description .............................................................................................. 25

4.1 Overview: Exposure Wizard .................................................................................. 25

4.2 Static Wizard Elements ......................................................................................... 27

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ii User Guide

4.2.1 Menu Bar ................................................................................................. 27

4.2.2 Tab Section .............................................................................................. 27

4.2.3 Info Section .............................................................................................. 28

4.3 Substrate Representation ...................................................................................... 31

5 System Startup .................................................................................................... 33

5.1 Powering Up .......................................................................................................... 33

5.2 Powering Down ................................................................................................ ..... 34

6 Job Setup ............................................................................................................. 35

6.1 Select Job .............................................................................................................. 36

6.2 Select Substrate Template .................................................................................... 37

6.3 Load Design .......................................................................................................... 38

6.3.1 Standard: First Exposure ................................................................ ......... 38

6.3.2 Standard: Alignment ................................................................................ 39

6.3.3 Series ....................................................................................................... 40

6.4 Convert Design ...................................................................................................... 41

6.5 Load Substrate ................................................................................................ ...... 43

6.6 Draw Structures ..................................................................................................... 46

6.6.1 Draw Image ............................................................................................. 47

6.6.2 Draw Line or Polygon ............................................................................... 48

6.6.3 Expose Crosses in Draw Mode ................................................................ 49

6.7 Setup Overlay Alignment ....................................................................................... 50

6.8 Expose Design ...................................................................................................... 54

6.8.1 First Exposure Procedure ................................ ................................ ........ 54

6.8.2 Overlay Exposure Procedure ................................................................... 55

6.8.3 Series Exposure Procedure ..................................................................... 57

6.8.4 Draw Mode Exposure Procedure ............................................................. 59

6.9 Unload Substrate ................................................................................................... 60

7 System Utilities and Tools .................................................................................. 63

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7.1 Control Panel ........................................................................................................ 63

7.2 Camera Window .................................................................................................... 65

7.3 Optimizing Alignment and Exposure Results ........................................................ 66

7.3.1 Unsatisfying Alignment Measurements .................................................... 66

7.3.2 Unsatisfying Exposure Results ................................................................ 67

7.4 Back Side Alignment ............................................................................................. 68

7.4.1 Overview of BSA Marker Zones .............................................................. 68

7.4.2 BSA Exposure Preparation ...................................................................... 70

8 Operator Maintenance and Troubleshooting .................................................... 71

8.1 Operator Maintenance .......................................................................................... 71

8.2 Troubleshooting .................................................................................................... 72

8.3 TeamViewer Software ........................................................................................... 73

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List of Figures

iv User Guide

List of Figures

Figure 1: System components .............................................................................. 13

Figure 2: Elements of the laminar flow box ........................................................... 15

Figure 3: Temperature control readout ................................................................. 15

Figure 4: System support ................................ ...................................................... 17

Figure 5: Operator Panel ...................................................................................... 17

Figure 6: Stage system with optics plane .............................................................. 19

Figure 7: Interferometer function ........................................................................... 21

Figure 8: E-rack components ................................................................................ 22

Figure 9: Orientation of stage and design ............................................................. 23

Figure 10: Machine-related design rotation ........................................................... 23

Figure 11: Rotation of coordinate system on chuck .............................................. 24

Figure 12: Location of coordinate pairs ................................................................. 24

Figure 13: Wizard window overview ..................................................................... 25

Figure 14: Unloading options in Standard Mode and Series Mode ....................... 60

Figure 15: Camera window ................................................................................... 65

Figure 16: BSA marker zones overview ................................................................ 69

Figure 17: Orientation on wafer for BSA ............................................................... 70

List of Tables

Table 1: Field of view (top side, back side) ........................................................... 20

MLA150

1 Introduction

User Guide 1

The MLA150 is a high speed direct write lithography tool extended by capabilities formerly only available on Mask Aligners. It can expose the patterns directly without prior fabrication of a mask resulting in a significantly shorter prototyping cycle. It offers topside alignment and backside alignment with high accuracy, and a light source which generates sufficient dose to expose even thick and less sensitive resists. The MLA150 allows using substrates of any size and shape and provides flexible change of pattern, distortion compensation and other software corrections. The system can produce structures down to 1 µm. The alignment accuracy can be as good as 250 nm under optimized conditions.

1.1 About this User Guide

This user guide gives information and instructions on how to handle the MLA150 system properly. It is important that every person who intends to work with the system reads this guide in order to avoid possible mishandling leading to damage to the system or to persons. Therefore, by all means, read the safety instructions carefully before starting work with the system. The guide assists the user in performing the exposure procedure beginning at system startup and ending with the exposure procedure itself. The subchapters in 6 Job Setup build a sequence of tasks that have to be executed in order to prepare the exposure job.

Additionally, you find a description of the system and of the Exposure Wizard. Also information about system utilities and troubleshooting are given in the final chapters.

Technical data can be found in the related document Technical Data Sheet To facilitate following the instructions and information, a list of conventions indicating the

type of information is given here.

Note:

Indicates that additional information or advice follow to get best results.

Signalizes that this is the first step of a step-by-step instruction followed by further steps



Indicates a result which the user can see or hear. It can also just be an intermediate result and can therefore be followed by further steps of the same instruction.

Indicates that the following information or instruction is an alternative step e. g., to abort a process or to be referred to another instruction or chapter.

This symbol is used to mark a location in a figure that is related to the instruction. The numbers in the symbol correspond to the number of the step in the instructions.

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1.2 Contact

Should you need assistance, please contact your local service office:

You can also reach Heidelberg Instruments via email: himt@himt.de, or visit our site on the internet: http://www.himt.de

China:

Europe:

Heidelberg Instruments Service China Rm.101, Block 1, Animation Park, Yuehai Street, Nanhai Road, Nanshan Distr., Shenzhen 518045 China Phone:+86-755-8301599-1 / -2 / -7 Fax: +86-755-8301599-4 Email: service_china@himt.de

Heidelberg Instruments GmbH Service Department Tullastraße 2 69126 Heidelberg Germany Phone: +49-6221-3430-0 Fax: +49-6221-3430-30 Email: service_europa@himt.de

Japan:

Korea:

Heidelberg Instruments Service Japan Germany Center for Industry & Trade 1-18-2, Hakusan Midori-ku, Yokohama, 226-0006 Japan Phone:+81-45-938-5250 Fax: +81-45-938-5251 Email: service_japan@himt.de

Heidelberg Instruments Service Korea #316 Expo Officetel, 381 Mannyeon-dong, Seo-gu Deajeon, 35203 South Korea Phone:+82-42-482-1668 Fax: +82-42-482-1669 Email: service_korea@himt.de

Taiwan:

USA:

Heidelberg Instruments Service Taiwan 6F-5, No. 192 DongGuang Road Hsinchu City, 30069 Taiwan Phone +886-3-5715188 Fax +886-3-5715388 E-Mail: service_taiwan@himt.de

Heidelberg Instruments Inc. USA 2807 Oregon Court, Unit E2 Torrance, CA, 90503 USA Phone:+1-310-212-5071 Fax: +1-310-212-5254 Email: service_usa@himt.de

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User Guide 3

1.3 Related Documentation

Heidelberg Instruments offers several further manuals related to the machine and its operation. If you did not get one of these or need an update, please contact Heidelberg Instruments, Germany (1.2 Contact). See the list of related documents below:

 Pre-Installation Guide

Environmental and electrical requirements, sizes and weights of components etc.

 PI- Site Inspection checklist

Checklist containing questions regarding the conditions of the costumer’s installation site for the system.

 Safety guide

Describes necessary safety measures during move-in, installation as well as servicing and maintenance times.

 Conversion Software Manual

Manual for the HIMT conversion software used for data preparation and fractioning.

 Design Guide

Instructions on design rules and design creation.

 Maintenance Guide

Guide for Maintenance and Troubleshooting, as well as an overview of typical service tasks.

 Technical Data Sheet

Overview of the systems technical data.

 Quick Guide

Short instructions to execute an exposure.

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4 User Guide

MLA150

2 Safety

User Guide 5

The MLA150 protects operators from exposure to laser radiation, dangerous voltages or moving parts while operating the equipment. All moving parts, lasers and their associated optics are enclosed within a flow box. During operation, opening the flow box window will immediately stop any exposure or measurement process.

Still, it is vital that the operators and all other persons who are allowed access to the system have been informed about any remaining risks.

2.1 Intended Use and Limitations

The intended use of the MLA150 lithography system is to expose structures on photosensitive, non-flammable layers which are located on non-flammable substrates. These substrates must not exceed the specified maximum dimensions and must be free of damage such as scratches or cracks.

The MLA150 is intended only for professional use. The related user documentation is part of the product, and the user is under the obligation to read the documentation before using the product.

Every other purpose of use than that stated in this section is prohibited. In case of damage by using the product outside this stated purpose, no liability is assumed by the Heidelberg Instruments Mikrotechnik GmbH.

In addition to the intended use stated above, the following purposes of use are prohibited and defined as misuse:

 Operation outside the operating data stated in the data sheet or in the sales

confirmation.

 Operation with materials other than the approved materials.  Change of the factory settings by unauthorized persons.  Use of attachment parts other than Heidelberg Instruments components.  Operation of the system in a potentially explosive environment or aggressive

atmosphere.

No untrained person, or person not familiar with the contents of the following sections is allowed to operate the system or work in its close environment. If instructions are not followed carefully, danger to personal health and damage to the equipment is at risk.

At all times, follow all warnings and instructions given in this manual, the system software, safety labels on the system, or by our engineers.

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2.2 Conventions

Throughout this manual there are safety warnings. To classify the degree of danger in each of these situations, this guide uses the conventions defined in ANSI Z535.6-2011:

Laser beam hazard

Electrical shock hazard

General warning

Toxic hazard

Corrosive material hazard

Flammable material hazard

Pinch point hazard

2.3 Laser Safety

The MLA150 employs two types of continuous wave lasers, one for position measurement of the stage (interferometer laser), one for design exposure (exposure laser). When the window is closed, all laser light is blocked or absorbed, and the system is effectively of laser class 1.

When the window is opened for loading or unloading, the interferometer laser beam is accessible. Under this condition, the system has the same laser class as the interferometer laser in use, which is laser class 2.

Laser Type

Wavelength (nm)

Power (mW)

Laser Class

HeNe

632

< 6

The exposure laser beam is a powerful beam that is usually covered completely by optics covers. Power and wavelength of the exposure laser depend on the specific configuration, but the exposure laser beam is always dangerous for the eye, sometimes also for the skin. Even reflected light may be dangerous.

If the optics covers are opened, the accessible energy is of the class 4 category (DIN EN-60825-1).

Danger indicates a hazardous situation, which, if not avoided, will result in death or serious injury.

Warning indicates a hazardous situation, which, if not avoided, could result in death or serious injury.

Caution indicates a hazardous situation, which, if not avoided, may result in minor or moderate injury.

Denotes warnings against possible misuse that can lead to machine damage.

Laser Type

Wavelength (nm)

Power (mW)

Laser Class

Diode, blue

405

≤ 10000

Diode, UV

375

≤ 3000

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If conditions require the opening of the optics covers, such as for servicing or troubleshooting by trained service personnel, then personnel must observe all precautions required for a laser of above mentioned class in the whole area surrounding the MLA150.

Eye injuries and/or skin burns!

Severe damage to the eye and possibly to the skin can be caused by laser radiation of class 3B or 4

 Avoid possible direct or indirect exposure of eyes or skin to

laser radiation at all times.

 Do not operate the system with open optics cover if not acting

under explicit instruction of an HIMT service engineer.

 Do not enter any area cordoned off by HIMT service

engineers during adjustment work.

 Do not put anything reflective or flammable into the beam

path.

If the system has to be operated with open optics cover e.g., for trouble shooting:

 Cordon off the area and place warning signs.  Wear appropriate safety goggles. Note that these cannot

protect long against a direct beam, but are only meant as protection against stray light! Also keep in mind that you cannot see the laser beam with goggles on, so the risk of skin burns increases.

 Use the lowest possible laser power or reduce the power as

far as possible with filters.

 Never leave the laser on when unattended. Make sure only

qualified personnel may switch on the laser in such a machine state.

 Do not place reflective objects in, or near the laser beam path.

Laser light scattered by reflective objects can be as damaging as the original beam. Objects such as rings, watchbands, and metal pens or pencils can be hazardous.

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2.4 Electrical Safety

A CEE type 220-240 V, 16 A single-phase cable connector supplies operating power in the MLA. It is also possible to attach a local-type cable to a local-type wall connector. Please refer to the Pre-Installation Guide for details.

Electrical Shock!

Fatal electrical shock and/or severe burns can be caused by the supply voltage of up to 240VAC 16A for the system, and up to 420VAC 32A for certain laser types.

 Never use the equipment if cables or plugs have been

damaged.

 Plug the MLA and its components only into approved outlets

with correct ground. Power requirements are described in the Pre-Installation Guide.

 Ensure that both the voltage and frequency of a power source

match the voltage and frequency stated on the equipment’s

electrical label.

 Not all power cords have the same current ratings.

Household extension cords do not have overload protection and are not meant for use with sensitive electronic equipment. Never use household extension cords for any component of the MLA.

 Always follow the five safety steps if equipment containing

electrical circuits with voltages >50VAC has to be opened: disconnect, apply restart lockout, check if equipment is deenergized, ground / short circuit equipment, cover neighboring elements that are still energized

 If access to the interior of any electronics component is

necessary while system is in operation, exercise extreme caution. Only qualified service personnel may have access to the interior.

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User Guide 9

2.5 Other Risks during Operation

Injuries by moving parts or heat!

If covers are removed, the operator may be exposed to dangerous collisions with moving parts, or heated components.

 Do not remove any covers that are fixed with screws  Heed the warnings if removing any other covers

Pinch risk by closing window!

Mild pinch injuries are possible if fingers are brought between the upper window frame and the window while the window closes. The loading window is driven pneumatically with low pressure. It does not have enough force to injure a body or limb, but skin may be pinched.

 Don not close the window while resting a hand at the upper

frame or upper window edge.

 Do not put a hand through the already closing window.

2.6 Interlock

To protect the operator from hazards by laser light or moving stage, interlock circuits prevent stage movement and access to laser light as soon as the window opens. A safety switch stops the stage, holding it in position, and closes the laser shutter. If an exposure has been running at that moment, the result is irreversibly lost.

The stage interlock can be overridden by service engineers by a key switch for servicing, together with a confirmation from the menu. While this service mode is activated, the main bar and background of the Exposure Wizard turns red.

Injuries by moving parts or laser light!

While the system is in service mode, dangerous levels of laser light are accessible, and the stage can move with window open. Only HIMT service engineers are allowed to put the machine into service mode.

 During servicing or maintenance by service engineers, heed

the warnings given in the Safety Guide.

 If service mode was left active accidentally, switch back to safe

mode and remove the key. Return it to the service local office.

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2.7 Labels

Flowbox front

E-Rack

REAR DOOR

FRONT DOOR

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User Guide 11

Optics cover: front cover, side covers, rear cover

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User Guide 13

This chapter gives a short description of the MLA150 lithography system. The MLA150 system consists of the following individual components:

 Lithography Unit  Electronics Rack  Cooling water supply (not explicitly described in this document)  Operator workstation

The main principle of the functional interaction between the system components is as follows:

A workstation comprising two computer monitors, a keyboard, a mouse and the User PC, that is located inside the electronics rack, represents the interface between user and system. The user controls the system via our graphical user interface on the User PC. This data is processed by the components located inside the electronics rack such as the stage controller which communicates with the stage and controls its movement based on the feedback given by interferometers that are placed in the main unit.

The system has two cooling water supply units, called chillers. One of them makes sure that the system runs in a stable environment in terms of temperature. The other one serves as cooling unit for the laser and the motors.

USER PC

design positioning alignment sequences system parameters

conversion: CAD design

conversion

exposure data

MLA

Main Unit

Flow Box

sensors

control

cooling water supply for Flow Box

cooling water supply for Main Unit

ELECTRONICS RACK

data

Figure 1: System components

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14 User Guide

3.1 Lithography Main Unit

The Main Unit comprises the following elements:

 Flow box  Granite Construction  Optics System

3.1.1 FLOWBOX

The flow box is the housing of the lithography system and protects the MLA150 from damage. It also provides a stable environment in terms of temperature, laminar flow and clean air. This is of importance because only such a stable environment guarantees constant exposure conditions which guarantees the smallest possible variation of exposure parameters. The covers of the flow box are removable, but only for service purposes.

Injuries by moving parts or laser light!

Severe damage to the eye and possibly to the skin can be caused by laser radiation of class 3B or 4

 Do not open the covers of the flow box.  Flow box covers may be opened only by, or under direct

instruction from, experienced service personnel!

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ELEMENTS OF THE LAMINAR FLOW BOX:

TEMPERATURE CONTROL UNIT

The flow box is temperature controlled by means of regulated heating of the incoming air. The air is cooled down by the water-cooling unit and then reheated to

TEMPERATURE CONTROL UNIT

DISPLAY

SWITCH PANEL

CASTOR WHEEL

WINDOW

LIGHT

ACTUAL TEMPERATURE

TARGET TEMPERATURE

RESET BUTTON

HEAT OUTPUT REGULATOR

Figure 2: Elements of the laminar flow box

2 3 4

Figure 3: Temperature control readout

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16 User Guide

the required process temperature. The temperature control unit is located within the top compartment and has a display readout accessible from the outside through a hole in the flow box cover. In case the temperature exceeds +65°C inside the flow box, which can be caused by a malfunction of the fan, the control unit shuts down the heating system. The push button switch turns red. The heating system can be reset by pushing the button once but this should only be done if the reason for the failure is known. The display readout has a small icon in the left, blinking in regular intervals. This icon shows the activity of the heat output regulator. If the icon blinks periodically then the heat regulation works properly. If the icon is illuminated or not illuminated without any periodical change, then the temperature control unit is not working trouble-free anymore. It is recommended to shut down the system and call one of Heidelberg Instruments service offices (see 1.2 Contact).

CASTOR WHEELS

The flow box stands on eight castor wheels that have locking brakes in order to provide a stable position. These castor wheels are not height-adjustable. The machine is leveled by adjusting the four feet.

SWITCH PANEL

At the front side of the flow box several buttons are located. The green button is used for powering up the system, the red one is for powering it down. The button in the middle is the emergency off button. For opening and closing the window, the push button is used. The flow box provides a light source for inside, which is, depending on the application, yellow or red light. The light switch is located between the emergency off button and the window push button.

WINDOW

The window is opened only for loading and unloading purposes. During operation, the window cannot be opened for safety reasons. The push button at the front of the flow box opens and closes the window by means of compressed air. This button is disabled while an exposure is running.

On (I)

Off (0)

Emergency Off

Window push button

Light push button

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User Guide 17

3.1.2 SYSTEM COMPONENTS

SYSTEM SUPPORT

A heavy-duty aluminum construction and four buffers that are filled with air to ensure vibration isolation support the granite base plate. To avoid any unnecessary bending forces in the base plate, these buffers are arranged in a triangular geometry (the two buffers at the front side are close together and act as one point).

HEIGHT-ADJUSTABLE FEET

The granite construction stands on four height-adjustable feet. By varying the height of the feet the system is leveled in correspondence with the ground condition in the location the system is installed. The castor wheels of the flow box are not heightadjustable.

BASE PLATE (MAIN BLOCK)

The main unit has a granite base that gives stability to the system. It has been selected for its low thermal expansion coefficient. The granite base plate is supported by air buffers that ensure effective vibration isolation and has threaded holes to accept other system components. Medium and high-power lasers are mounted at the bottom of the base plate to minimize heat generation in the areas that are sensitive to heat.

OPERATOR PANEL

The operator panel has a push button (1) that opens the vacuum inlet to fix the substrate on the chuck. For observing the vacuum status, a display (2) shows the current vacuum status. However, it is not necessary to observe the status because the wizard informs about vacuum supply problems. The panel also contains two LED lights (3) indicating the status of the laser. The lights are on throughout the whole exposure procedure. When the window is open, the lights are off indicating that the laser(s) is (are) off (see 4.2.3 Info Section).

Figure 4: System support

Figure 5: Operator Panel

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18 User Guide

STAGE SYSTEM

The stage is equipped with linear motors in both axes. They provide smooth and constant movement with low positioning errors. One air bearing and one roller bearing support the movement in y-direction whereas the x-axis is equipped with two roller bearings.

The stage carries the frame in which the chuck is located. There is one chuck for all substrate sizes. The substrate is hold down and kept it in place by vacuum suction. The chuck features a vacuum suction hole in the center and four small vacuum slits through which the vacuum reaches the substrate. Due to the viewing slots, backside alignment is possible without installing a different chuck. One of the slots is surrounded by a recess in which the adjustment aid is inserted to provide proper substrate placing on the chuck. Another one is also surrounded by a recess giving space for a tweezer to facilitate substrate loading.

VIEWING SLOTS

VACUUM SUCTION SLITS

VACUUM SUCTION HOLE

RECESS FOR TWEEZER

RECESS FOR ADJUSTMENT AID

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User Guide 19

OPTICS PLANE

The optics system is located on a smaller granite top plate supported by the base plate and its granite side elements. The optics plane contains the optical elements and all camera components. The write head stands at the end of the optical path and is mounted to this plate with downward beam direction facing the substrate.

INTERFEROMETER HEAD

OPERATOR PANEL

STAGE

CHUCK

WRITE HEAD

OPTICS PLANE

Figure 6: Stage system with optics plane

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3.1.3 OPTICS SYSTEM

DIGITAL MICROMIRROR DEVICE (DMD)

The DMD is an electrical input and optical output micro-electric-mechanical system for spatial light modulation. It is composed of an array of micro light switches containing individually controlled micro mirrors which correspond to the pixels in the image to be displayed. Laser light is modulated by this device to project and transfer a pattern into positive or negative resist.

LASER UNIT AND OPTICAL ELEMENTS FOR BEAM GUIDANCE

The laser beam is emitted by several laser diodes, coupled in an optical fiber and projected on the DMD. The optical elements guide the modulated light through the system. The light beam passes the write head and is finally projected on the substrate.

CAMERA UNIT

The camera unit comprises one camera with low resolution, one with high resolution and one overview camera. The cameras also feature a light source and make it possible to inspect and measure the exposed substrates. Additionally, the cameras are used for accurate alignment of a design with existing structures. Here, the High Res camera is the appropriate choice due to its high resolution. In cases where the alignment marks are larger than the field of view of the High Res camera, switching to the macro camera is recommended. The overview camera is not appropriate for alignment. Additionally, it does not show the complete surface of the substrate due to mechanical limits. The camera image is transferred to the User PC via camera software that opens in its own window. Systems with backside alignment have a second camera unit for back side viewing mounted inside the stage and looking pointed to the substrate.

PNEUMATIC AUTOFOCUS

The pneumatic autofocus serves to keep the focal point of the write beam stable on the surface of the substrate. For probing the distance, compressed air passes through the write head and leaves it through a nozzle. Once the write head is close enough to the substrate, a pressure builds up between the nozzle and the substrate, which is monitored by a pressure sensor. The pressure sensor transmits the information to a controller which regulates the write head movement. The defoc value shows the focus position of the write head with respect to the offered

Camera type

Field Of View

(size of the substrate area that can be seen)

Top Surface

Back Surface

High Res

190 μm x 140 μm

min.172 x 130 µm

Low Res

640 μm x 480 μm

min 364 x 274 µm -

Overview

20 mm x 20 mm

top side only

*Overview cannot access the entire surface of the substrate due to mechanical limits.

Table 1: Field of view (top side, back side)

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User Guide 21

defocusing range [-10 to 10]. This range is necessary to adapt the focus distance to an appropriate value which mainly depends on resist thickness and thus varies.

INTERFEROMETER

The laser interferometer is an optical device for measuring the stage position. The machine achieves its required positioning precision with this important element.

WRITE HEAD

The write head is mounted to the optics plane. The focal length of the write lens determines the resolution of the system.

Interferometer

Laser Unit

(HeNe)

X Mirror

X interferometer unit

Y interferometer unit

Stage

Y Mirror

Figure 7: Interferometer function

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3.2 Electronics Rack

The electronics rack consists of several units. These units drive and control the system and provide communication with the operator of the system. The following electronic units are located inside the electronics rack:

1 USER PC WITH CONVERSION

The User PC is a communication interface between user and system by means of the graphical user interface (GUI). The User PC runs Linux on a virtual machine which runs the conversion software. This software is necessary for design conversion. Design files in Gerber, DXF, CIF or GDSII have to be converted into a machine file format, the LIC format. LIC stands for Laser Internal Code. Only this special file format can be read by the MLA system.

2 STC-RACK

The STC-Rack is a system control unit consisting of several elements such as the stepper motor driver, the autofocus electronics or the laser shutter control.

3 STAGE CONTROLLER

The Stage Controller drives the stage, reads the interferometer data, triggers the laser and tells the DMD (digital micromirror device) when to switch to the next frame. It is the system that coordinates the exposure procedure.

4 POWER SUPPLY AND EMERGENCY STOP MODULE

This unit responsible for power distribution.

5 INTEGRATED NETWORK HUB

The Integrated Network Hub connects the multiple devices and make them work together on a single network.

1 2 3

Figure 8: E-rack components

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User Guide 23

3.3 Orientation of Stage and Design

It is important to load the substrate with the correct orientation on the center of the chuck. The coordinate system of the design to be exposed must match the direction and orientation of structures already exposed on the substrate.

The coordinate system of the stage is oriented such that the y-axis corresponds to a left-right movement and the x-axis to a backward-forward movement (see Figure 9) when standing in front of the machine.

The design is exposed rotated by 90 degrees in clockwise direction (Figure 10).

loading side

90° clockwise

Figure 10: Machine-related design rotation

Figure 9: Orientation of stage and design

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24 User Guide

Thus, the coordinate system of the design is also arranged rotated by 90 degrees clockwise (Figure 11).

For easier orientation on the chuck regarding the design coordinates, the following figure gives an example of alignment crosses and their location on the substrate.

-x

-y

+x +y

- y

- x +y

90° clockwise

-x

-y

- y

- x

Figure 11: Rotation of coordinate system on chuck

loading side

Figure 12: Location of coordinate pairs

loading side

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User Guide 25

The MLA150 offers quick setup of exposure and alignment aided by the Exposure

Wizard. This intuitive user interface guides the operator through the steps of an

exposure set up. To start the wizard, double-click on the link icon.

4.1 Overview: Exposure Wizard

The Exposure Wizard has its own window. This window stays open throughout the entire configuration and exposure procedure (Figure 13). It contains the following main elements:

MENU BAR

TAB SECTION

INFO SECTION

FRAMES

INFO FIELD

NAVIGATION

BUTTONS

PANEL

Figure 13: Wizard window overview

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MENU BAR

The menu bar is located at the top of the window, offering a number of menu utilities.

INFO SECTION

The info block gives information about the hardware condition and the progress or status of the current exposure setup.

PANEL

The panel is located below the info section. This panel changes according to the tasks that the system has to perform. In figure 13 the panel’s name is Setup Job panel. Inside the panel are buttons and frames.

FRAME

The panel contains frames e.g., the Layer frame, where the design file and other options are selected. The frame has mandatory fields that have to be filled with values, and fields that can be filled optionally. The mandatory fields are highlighted in orange and turn green once a value has been entered. The optional fields are highlighted in green before and after the entry of values.

Throughout this manual you find instructions like "double-click Design". In this case, you are instructed to double-click the value field with the title Design not the word

Design.

BUTTONS

A click on these buttons usually opens another window where you can select items or set options

NAVIGATION BUTTONS

At the bottom of the wizard window, you find navigation buttons e.g., Load Substrate or Continue. The functions and names of the buttons depend on the

selected exposure mode. These buttons can stay disabled until certain tasks are finished.

INFO BOX

Every panel contains a yellow text box, giving information and instructions on the current task.

TAB SECTION

A block with two tabs is located below the menu bar. In one tap (Exposure Setup) a tree view shows the procedure steps the system has to execute. The other tab (Info) shows a list of startup messages (refer 4.2 Static Wizard Elements for more details).

In the following subchapter, you find detailed information about the Exposure Wizard elements.

TITLE

VALUE

MANDATORY

OPTIONAL

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4.2 Static Wizard Elements

4.2.1 MENU BAR

FileExit:

To leave the wizard and close the window

ToolsControl Panel:

Activates the Control Panel (see 7.1 Control Panel)

ToolsInitialize Stage:

To initialize the stage in case the hardware info shows that it is not initialized

UserSelect User:

UserManage Users:

To manage the administration rights of the different users

4.2.2 TAB SECTION

The Exposure Setup Tab shows a tree view of the steps to be completed with the wizard from job setup to exposure and unloading. It is a graphical representation of the sequence of panels making up one exposure job. As a kind of panel map it can be taken for orientation.

The green rectangle shows the options available in the selected Exposure Mod. The green check indicates that the task is done.

The Info Tab shows a list of startup messages informing the user about the condition of the system after startup.

The control system checks the communication between the electronics and the hardware components. A list of exposure files and exposure reports is shown featuring a search bar for easy retrieval of exposure information.

Note:

If the Hardware Info Section shows a red cross, open the Info Tab and check the startup messages to find out where the problem is.

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4.2.3 INFO SECTION

The Info Section consists of four subsections:

 Exposure Info  Alignment Info  Progress Info  Hardware Info

Exposure Info

 Job Name is a combination of the word job and the job number. It is editable in the

Job frame by double-clicking into the Job Name value field.

 No. shows the auto-incrementing number of the job, it is not editable.  Substrate Size[mm] shows the size of the substrate that is currently loaded.  Design Name shows the name of the design that is currently loaded.  Design Size [mm] shows the size of the design.  Dose [mJ/cm²] shows the exposure energy for the current job.  Height shows the height of the substrate on the cuck.  Layer shows the layer that is currently being prepared for exposure.  Mode shows the exposure quality level chosen at conversion. Quality means high

level, Fast means lower quality level but faster completion.

 Defoc shows the defocus value selected for the current exposure. The defoc with a

range between -10 to 10 allows fine tuning of the exposure focus (for more information see 3.1.3 Optics System: Pneumatic Autofocus). This value can be adjusted before starting the design exposure (6.8 Expose Design)

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Alignment Info

This info box has two tables: Expose Cross Positions shows the positions of the alignment crosses set during the

setup of the layer previous to the layer with the design that is to be aligned. For instance, when setting up the First Exposure job the coordinates of the exposure crosses for the next layer can be determined and exposed together with the First Exposure layer.

Align Cross Positions shows the positions of the alignment crosses taken from the template file. For orientation regarding the location of the coordinate pairs on the substrate see 3.3 Orientation of Stage and Design.

Progress Info

The Progress Info box gives information about the progress of the exposure.

 Exposure Status shows the status of the exposure job.  Design Number shows the number of the design that is being exposed.

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 Stripe Number shows which stripe is being exposed at the moment.  Time [hh:mm]. shows the time that the exposure takes in total.  Remaining Time [hh:mm] shows the time that the exposure is still requiring to be

finished.

Hardware Info

The Hardware Info box shows important information about the system status. The Refresh button updates the information stated in the tables. The Stage Position fields

show the x-coordinate and the y-coordinate of the current stage position. A click on Refresh updates the fields to show the current position.

The Status list informs about the status of the system devices. If there is a red cross instead of the word OK, click Refresh. If the status is still the same, go to the Info Tab and click Status Messages. Here, you can see why the status does not show OK.

The Numeric Values list shows the condition of the system parts in numeric values. These values are only interesting for service staff or users with administrator rights. If any of the values is not in the normal range, the Status list shows the red cross icon instead of the word OK.



REFRESH

STAGE POSITION

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4.3 Substrate Representation

In the menu panel you find a simple graphical depiction of the substrate showing the design position on the substrate. The position of the camera is also displayed in order to see which part of the substrate is currently visible in the camera image.

Depending on the kind of substrate shape (plate or wafer) the menu offers two different substrate visualizations. On the substrate, the design position and size is displayed by a red rectangle. The camera is depicted as a blue rectangle.

Camera

Design

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The horizontal and vertical measure lines indicate the real size of the substrate. The size of the design representation and the size of the camera are scaled in relation to these measure lines.

To move the design to a certain position on the substrate, use the Control Panel. Alternatively, drag the camera (hold mouse button down while moving) to the desired location. The design follows when the camera position is set to zero by clicking Set zero in the Control Panel.

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This chapter describes how to power up and power down the MLA150. For powering up and down the system the buttons at the front of the flow box are used.

5.1 Powering Up

Powering up the system:

If not already done, switch on the main switch at the e-rack.

Allow 60 seconds to boot the power supply.

Depending on the system configuration, switch on the User

PC.

To switch on the system power, press the On (I)-button at the

front of the flow box.

 You can hear one click and another click 3 seconds later.

In case the system was switched off by using the EMERGENCY OFF button:

Release by turning it in the direction indicated on the button. Otherwise the

system power cannot be switched on.

Press the green On (I)-button.

 You can hear one click and another click 3 seconds later.

Note:

If power is not coming up, check whether the main breaker on the bottom of the electronics rack is turned off. Turn on the main breaker again!

Switch on the displays and the User PC, if it is not running.

In case the power supply was interrupted (e.g. by a blackout)

Press the green On (I)- button.

 You can hear one click and another click 3 seconds later

Reboot the User PC.

Starting the Exposure Wizard:

Click the shortcut at your desktop.

On (I)

Off (0)

Emergency

Off

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 At each startup, the menu checks for necessary component initializations. A

window shows the status of hardware initialization

5.2 Powering Down

Powering down in emergency case:

In case of emergency, press the EMERGENCY OFF button at the front of the flow box.

Standard power down procedure

Close the Exposure Wizard by selecting FileExit from

the menu bar. Shut down the User PC. Press the red Off (0) – button.

 The system shuts down.

Complete Shutdown

Execute the standard power down procedure and then turn off the main breaker that is located on the front of the power distribution rack at the bottom of the electronics rack (see 3.2 Electronics Rack).

Note:

 In general, the system should be powered down completely only if

absolutely necessary. If the exposure laser is off, idle power consumption of the system is low, and keeping it in standby enhances stability.

 We do not recommend to power down the system if the idle time period is

less than at least one week.

Powering down for maintenance

The main circuit breaker in the bottom compartment of the electronics cabinet is equipped with holes for a padlock. If the system is powered down for maintenance or servicing, after above steps, secure the main circuit breaker in the Off position with such a padlock.

On (I)

Off (0)

Emergency Off

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As mentioned before (4 Wizard Description), the MLA150 provides an exposure wizard that guides the user through the steps needed to perform an exposure. The following subchapters build a sequence of actions that have to be executed one after the other. To use the wizard efficiently, follow the instructions given in this chapter. The following figure is a “panel map” showing the way through the wizard panels.

Load Substrate

Unload Substrate

Setup Job

Select Job

Select Substrate Template

Load Design (Convert Design)

Exposure

Alignment

Alignment:

Exposure

Series

First Exposure

Draw Mode

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6.1 Select Job

To start the wizard, double-click on the desktop. The Exposure Wizard opens and automatically creates a new job. This job has a Name and a Number. The name is editable and can be changed by clicking into the Name field. The number is fixed and auto-incrementing.

If you do not intend to start a new job, you can also choose from the following options:

Continue or repeat a job:

 Click Load Job.

Repeat an exposed layer of that job:

 Click Restart Job and select the job you would like to repeat. The process

data of the selected job is deleted and a new job is set up with the same settings but with a new job name/number.

Start another new job after you have finished an exposure job:

 Click New Job. The new job has a new number and a new, but editable,

name. Continue with the instructions for a new job.

Use the new job that has started automatically with wizard startup:

 From the dropdown list, select one of the available exposure modes:

Standard:

To expose a single design for each layer. Overlay exposures are possible in this mode.

Series:

To expose designs (e.g. dose test) several times at different positions with varying parameters (dose or/and defoc). It can

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also be used for finding the appropriate dose and defoc relation for the exposure.

Draw Mode

To create boxes, circles or ellipses of arbitrary size limited only by the camera field. Used for creating connections between structures or for repairing imperfections in structures of an exposed layer.

After you have set up the desired job, choose the appropriate substrate and the corresponding substrate template at the system (see Substrate Template Selection).

6.2 Select Substrate Template

The system also needs to be provided with the information about the chosen substrate. It offers a list of templates. In case the required template is not available in the list, it is possible to load a new substrate template (only for authorized users).

For selecting a substrate template, follow these instructions: In the Substrate frame:

Double-click into the value field titled Substrate Template. From the list, select your substrate size or at least the shape e.g.,

automatic_round if you intent to load a wafer.

Above the list, click Load.

 The Substrate frame now displays the selected substrate size or shape and the

field is highlighted in green. That means that the task of substrate template selection is done. If a substrate size was selected the fields Size X, Size Y, Diameter and Thickness are filled with the corresponding value.

1 1 3

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6.3 Load Design

In Draw Mode there is no design loading procedure because this mode is for exposing boxes, circles and ellipses of arbitrary size limited only by the camera field. Skip this subchapter and go to 6.5 Load Substrate.

After you have selected one of the exposure modes (see 6.1 Select Job) and determined the appropriate substrate template (see 6.2 Select Substrate Template), you load the design. For loading a design that is not in the list, follow the instructions given in 6.4 Convert Design. The following sections contain instructions on design loading. Even though the loading procedures differ only slightly from each other in the different modes, read the section that corresponds to the exposure mode you are about to use.

6.3.1 STANDARD: FIRST EXPOSURE

In the Layer frame:

If available, select a laser from the dropdown list in the Laser field. Double-click into the value field titled Design. A panel opens containing a list of

available design files.

From the list, select the required design with a left-click. Click Load. Alternatively, double-click on the design name.

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 The design is now listed in the Layer frame.

Optional: Double-click the value field titled Resist and select the appropriate

resist type for your application. The recommended dose for exposures on that type of resist is listed automatically in the Sensitivity field. In the Thickness field the thickness of the resist is displayed. Select the wavelength for the exposure.

Optional: It is possible to load a template for alignment crosses which are

exposed on the layer. To load this template, double-click into the value field titled Expose Crosses and select a bitmap template file from the list. If the template size exceeds 800 x 600 px, the system shows a warning.

6.3.2 STANDARD: ALIGNMENT

For aligned exposures, Layer 2 is the first layer that can be chosen.

If available, select a laser from the dropdown list in the Laser field. Double-click into the value field titled Design in Layer 2. A panel opens containing

a list of available design files.

From the list, select the desired design file with a left-click.

Click Load. Alternatively, double-click the name.

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 The design is now listed in the Layer frame.

Double-click into the value field titled Align Crosses. A list opens showing

several templates with the crosses required for alignment procedures. A special

template called _Manual.xml is offered for cases in which the cross positions

should be selected in the alignment setup. The exposure is then executed with

the manually selected alignment positions which are saved afterwards as

[jobname]_AlignPos_L[No. of layer] (see below). Additionally, if a

different template was selected, alignment positions can be changed or even

ignored (see 6.7 Setup Overlay Alignment).

From the list, with a left-click select a template and click Load.

 The template file is now listed in the Align Crosses field.

Optional: Double-click into the value field titled Resist and select the appropriate

resist type for your application. The recommended dose for exposures on that

type of resist is listed automatically in the Sensitivity field. In the Thickness field

the thickness of the resist is displayed. Select the wavelength for the exposure

Note:

If the first layer does already exist on the substrate, it can be easily skipped.

6.3.3 SERIES

In Series Mode the template and design file is selected automatically when choosing Series Mode in the Set up panel (see 6.1 Select Job). The Layer frame turns into the

Series frame with different parameters than displayed in the Layer frame (see below). In case you need a different design file for your series exposure, follow the instructions

given in 6.3.1 Standard: First Exposure.

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6.4 Convert Design

If you have chosen a listed design file, skip to the next section 6.5 Load Substrate. For converting a new design, follow these instructions:

In the Layer frame:

Double-click into the value field titled Design. A page containing a list of designs

opens. At the bottom you find a button bar.

Click Convert Design. You are led to the conversion software window.

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In the Conversion window:

From the menu bar, select File New Job (alternatively click the sheet icon). You are asked to enter a name for the job. Enter a name and click Ok. Click Add, select a design format. A directory opens containing the source files

for the selected design format. From the directory, select the file to be converted into the LIC format. If necessary, change settings and / or use the viewer application (see related

document Conversion Job Manager for more details). Click Complete Task. A message box informs about the completion of the

process. If the status bar shows 100%, click Finish.

The conversion software closes automatically. Click into the wizard window to refresh the design list or click Refresh. The new

file is now listed and available for exposure.

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6.5 Load Substrate

After you have chosen the appropriate substrate, selected a substrate template and loaded a design, you can place the substrate on the chuck. The following instructions guide you through the loading procedure. You also get on-screen instructions inside the yellow Info Box.

The chuck is designed to facilitate the manual loading process. It has an indentation surrounding one of the four viewing slots for backside alignment. This indentation makes substrate handling on the chuck easier as it offers space for putting a adjustment aid inside.

ADJUSTMENT AID

The guide bar at the bottom of the adjustment aid is equipped with rest positions corresponding to the different wafer sizes that are possible to be loaded on the chuck. These rest positions are made visible on a measuring scale.

In the example the chuck is loaded with a 4”

wafer as it can be seen on the measuring scale matching the mark at the chuck.

Keep in mind to remove the adjustment aid from the chuck before starting an exposure.

In order to avoid possible damage caused by this adjustment aid, the system is equipped with a monitoring function based on a light barrier control. The Exposure Wizard disables the buttons that lead to all subsequent steps. The exposure function stays blocked until the tool is removed from the chuck.

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STEP-BY-STEP SUBSTRATE LOADING

In the Setup Job panel:

Click Load Substrate. The stage moves into loading position.

 The wizard moves on to the Load Substrate panel. Wait until the movement has

stopped.

At the lithography main unit:

Push the window button and release it again. The window

opens. Place the adjustment aid so that the guide bar, which is

located at the bottom, fits into the indentation at the

chuck. Adjust the auxiliary tool’s position to the substrate size. Use a tweezer to grab the substrate and place the

substrate on the chuck.

Note: Check for correct loading and head position. At the operator panel press the vacuum button. Make sure that the substrate is held tight by the vacuum. Remove the adjustment aid from the chuck. Check the substrate's orientation (see 3.3 Orientation of

Stage and Design).

Close the window by pushing and releasing the button.

Go back to the User PC.

Resist coated substrates get useless when exposed to white light!

Non-safe light may only be switched on if all substrates are stored in boxes impermeable to light. Otherwise, the substrates become useless.

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In the Load Substrate panel, click Continue. Check if the substrate is placed under the write head. If not, see below. If the

substrate position is correct, click Continue.

Note:

In case the substrate is not placed under the write head, click Cancel. The stage moves back to loading position. Start the loading procedure again and make sure that vacuum is switched on.

Note:

For small substrates the system issues a dialog box if the substrate type has not been completely defined in the step of substrate template selection.

 The system searches for the center of the substrate and gives information about

the progress via a message box. If you wish to abort the Find Plate Center procedure, click Stop in the message box and start the loading process again.

After the successful loading process, the system leads to the next panel:

 In Standard Mode with overlay alignment, the Alignment panel appears (6.7

Setup Overlay Alignment).

 In Draw Mode, the system offers the Draw Mode panel for creating boxes,

circles and ellipses (6.6 Draw Structures).

 In Standard Mode without overlay alignment, you are led directly to the

Exposure panel (6.8 Expose Design).

 In Series Mode, the Series panel shows up offering the exposure procedure

(6.8.3 Series Exposure Procedure).

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6.6 Draw Structures

After having selected the appropriate substrate, you can start drawing the image.

In the Draw Mode panel

In the Procedure frame, select the kind of shape to use for image drawing by activating the corresponding radio button:

 Draw Image: Activate this option to use the shapes offered in the camera

window: rectangle, ellipse, circle or bitmap file.

 Draw Line or Polygon: Use this option to draw lines or polygones (lines with

more than two points). Adjust the line width by using the spin control below the radio button.

 Expose crosses: Use this option to expose crosses for alignment orientation

without the design (in Standard Mode a design has to be loaded). In the Expose Crosses table you can load the bitmap file for cross exposure.

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6.6.1 DRAW IMAGE

Click Draw Image and select the area for the structure on the substrate inside the

camera window (use the Stage Control section for moving on the substrate).

In the camera window select the shapes of the structures that should be drawn

onto the substrate by clicking on the corresponding icon.

You can also load an existing file by clicking Load and selecting the file from the corresponding folder (usually C:\HIMT\Designs\Bitmaps). To directly load a bitmap file click BMP located below the structure icons.

To drag the structure to the desired position click into the structure and move the

cursor with the mouse button held down. To rotate the structure click into the green dot inside the structure and move the cursor without releasing the mouse button until the desired position has been found.

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To confirm the drawn image, click Submit in the menu bar of the camera window.

To clear the image, click Clear and start again.

To save the image, click Save, insert a name for the file and save it. To cancel the entire drawing procedure, click Cancel.

 After submission of the created image, work with the camera window is done.

Return to the wizard window and the Draw Mode panel in which the exposure

process can be started (see 6.8.4 Draw Mode Exposure Procedure).

6.6.2 DRAW LINE OR POLYGON

In the camera window, move to the area near to the

position of the first point of the line or polygon, so

that it is visible in the camera image. Click Set Point. In the camera window, a crosshair appears. Move

the crosshair by moving the mouse to the desired

position.

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Click the left mouse button at the position in which the first point of the line should

be set.

Move to the next point of the line/polygon by using the arrow buttons of the

Control Panel. Click Set Point. Repeat the set point procedure. Check the line position in the camera window and click Accept line. To draw a polygon, go on with the set point procedure and click Accept Polygon

to submit the polygon drawing.

 After accepting the drawn shapes, work with the camera window is done. Return

to the wizard window and the Draw Mode panel in which the exposure process

can be started (see 6.8.4 Draw Mode Exposure Procedure)

6.6.3 EXPOSE CROSSES IN DRAW MODE

If not selected in the Setup panel, a bitmap file has to be selected for every cross position:

Click Edit and select a template for every cross position. For selecting the same

file in every position, activate the checkbox Use first bitmap for all.

Enter the positions into the table. Click Edit again, to leave the editing mode.

Note:

Use Edit to change the template selection made in the Setup panel. Go to back to the original positions from the selected file, click Original.

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6.7 Setup Overlay Alignment

For exposing the first layer, skip this subchapter and continue with 6.8 Expose Design. The MLA150 is able to execute precise alignment exposures. In order to achieve best

results, the system offers top side as well as back side alignment. Back side alignment (BSA) is realized by a separate camera unit for back side viewing that is mounted inside the stage and looks to the substrate. Back side alignment is used in the same way as the normal top side alignment. For using the available alignment modes, choose standard exposure mode in the Setup Job panel.

Top side alignment is supported by three different camera types as mentioned before (see 3.1.3 Optics System). Back side alignment is supported by two cameras, low and high resolution. The overview camera is still active, but provides only top side view on the substrate.

The Low Res camera is the default camera. For alignment, it is recommended to use the High Res camera as its higher resolution is leading to best alignment results.

The alignment function offers two different alignment modes, Cross Alignment and Manual Alignment.

 Cross Alignment is an automatic cross detection mode and is recommended to be

used as standard mode.

 Manual Alignment is the manual mode for cross detection and is provided for

exceptional cases in which the automatic detection might not work properly.

In this chapter, you find the information necessary for executing alignment for overlay exposures. The alignment procedures of top side and back side do not differ from each other, so the following instructions are for both alignment types.

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Alignment Procedure

In the Alignment panel:

If the template _Manual.xml for manual setup of the alignment cross

coordinates was chosen, select Top Surface for top side alignment or Back

Surface for back side alignment from the dropdown list. The other templates

already contain this information. Choose a camera from the Stage and Camera Control panel:

Top Surface

Back Surface

Field of view

Low Res

640 µm x 480

BS Low Res

min. 364 x 274 µm

High Res

190 µm x 140 µm

BS High Res

min.172 x 130 µm

Overview*

20 mm x 20 mm

*Overview cannot access the entire surface of the substrate due to mechanical

limits.

From the Alignment Mode dropdown list choose between Cross Alignment and

Manual Alignment. This selection can be made for very single cross position.

Note:

Using the High Res/ BS High Res camera for alignment is recommended whereas the Overview camera is not useful for alignment procedures.

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Double-check the positions of the alignment crosses taken from the template file.

 Editing: The Edit button is used for changing the alignment cross positions.

Click Edit and enter new values. To delete one of the cross coordinates, delete the value and leave the field blank. If, for instance, you intend to skip the second cross position in the list, delete the value, copy the value from the third cross position field into it. Leave the third position field blank. To close the editing process, click Save. The positions are stored in a temporary file and turned into a permanent template after exposure start. To restore the original positions from the file, click Original.

 If the template _Manual.xml was selected, set the alignment marks

manually by using the Edit function. For every alignment cross enter the coordinates, click Save and then Accept Position.

Use the Stage Control frame of the Control Panel to move the cross into the

camera center (see 7.1 Control Panel).

Determine the alignment marks in:

A Cross Alignment Mode:

 Click Measure. The system measures the position of the cross and moves it

to the center of the camera window. Examine the positions and click Accept Position to confirm it. The procedure moves on to the next alignment cross. In the Pos field, the rectangle turns into a check.

In case of unsatisfying measurements see 7.3.1 Unsatisfying Alignment Measurements.

B Manual Alignment Mode:

 Click Measure. In the camera window, a crosshair appears. Move the

crosshair to the position in which the alignment marks should be set and click. The crosshair turns from green to orange.

Note:

For fine positioning use the arrow buttons. You can switch between continuous movement (jogging) and stepwise movement. In step mode enter the step size [µm] for X and Y direction into the corresponding fields. In the jogging mode, change the driving speed [µm/s] either by using the slider or by clicking into the corresponding field and entering the speed manually. Alternatively, click into the slider field and use the arrow keys for setting the speed

 To center the position of the alignment mark inside the camera window, click

Center Cross.

Note: It is possible to skip alignment positions by clicking Skip Position. This

only works if more than two points are available otherwise the button is disabled. In the Pos field the rectangle turns into a red cross icon indicating that this coordinate pair was ignored.

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Repeat the procedure for all alignment cross positions. Cancelling the alignment

procedure is possible by clicking Cancel. Alternatively, with Setup Job the

alignment procedure gets cancelled and the Exposure Wizard moves back to the

Setup Job panel. Click Continue.

 The design is now prepared for the exposure process. For information on how to

start the exposure process, go to 6.8 Expose Design.

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6.8 Expose Design

The system offers two standard exposure modes, one with and the other one without overlay alignment. Additionally, it is possible to execute series exposures in order to determine the appropriate defoc settings and dose settings for the current exposure job. In Draw Mode you skipped the design loading and created your own structures directly on the substrate inside the camera window (6.6 Draw Structures). The following sections give instructions on how to execute exposures in the different modes.

6.8.1 FIRST EXPOSURE PROCEDURE

After having loaded the design and the substrate, you are in the First Exposure panel.

Double-check the design name and the wavelength. If no default value is given, set the Dose by entering the value into the text field. Set the Defoc by selecting a value with the spin button [-10 to 10]. The defoc

allows fine tuning of the exposure focus. Optional: Activate Auto-Unload (see 6.9 Unload Substrate). Optional: Activate Expose Crosses if having selected a template before (see

6.3.1 Standard: First Exposure). Use Edit to change the coordinates or load a

different file. It is also possible to load a template here if not having done it before

in the design selection. Use Original to reset the coordinates to the values given

by the template file. Click Start Exposure.

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 The machine is exposing the design. If Auto-Unload is

not activated, then after completion of the exposure a dialog window pops up asking if the substrate should be unloaded. Click Yes, if you want the system to unload the substrate or No if the substrate should stay loaded on the chuck e. g., to expose the next layer.

It is also possible to click No and unload the substrate by clicking Unload in the

panel (see 6.9 Substrate Unloading).

6.8.2 OVERLAY EXPOSURE PROCEDURE

After having loaded the design and the substrate and having prepared the alignment crosses, the substrate is ready to be exposed.

In the Alignment: Exposure panel

Double-check the design name and the wavelength. If no default value is given, set the Dose value by entering it into the text field. Set the Defoc by selecting a value with the spin buttons (range -10 to 10). The

defoc allows fine tuning of the exposure focus. Double-check the Alignment Cross Positions. Optional: It is possible to load a template for alignment crosses which are

exposed on the layer. To load this template, double-click into the value field titled

Expose Crosses and select a bitmap template file from the list Chose from the Alignment Options section:

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 Rotation [mRad]: If the Use checkbox is activated, the system calculates the

rotation of the substrate.

 Scaling X/Y: The system compares the distance measured during alignment

with the distance given by the alignment positions. From the deviation a scaling factor results. On this basis the alignment design is shrunk or stretched in order to match the previous layer.

 Shearing [mRad]: The system compensates small distortions such as a

rectangle that appears more like a parallelogram.

Optional: Activate Auto-Unload. The system executes the unloading procedure

automatically (see 6.9 Unload Substrate).

Click Start Exposure.

 The machine is exposing the design. If Auto-

Unload is not activated, then after completion

of the exposure a dialog window pops up asking if the substrate should be unloaded. Click Yes, if you want the system to unload the substrate or No if the substrate should stay loaded on the chuck e. g., to expose the next layer.

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6.8.3 SERIES EXPOSURE PROCEDURE

After having loaded the substrate and the design, the substrate is ready to be exposed. You are in the Series panel of the Series mode.

In this panel several values have to be set for series exposure. Find the explanation of the panel elements below:

Mode: Three different selections are possible: Dose, Defoc or Dose and Defoc.

Number of fields: Use the spin button to select the number of fields to be exposed

In the Dose Series table, you set the parameters for the series with varying energy values.

In the Defoc Series table, you set the parameters for exposing the design with varying defoc values. The defoc allows fine tuning of the exposure focus.

In the bottom table, the Step size in x and y direction is determined.

Pay attention to the value in the Total range fields. If the total range requires more space than available on the substrate, an error message pops up.

For information about Auto-Unload and Unload see 6.9 Unload Substrate.

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When choosing Dose Series only, the Defoc value is fixed. The Dose value is fixed when Defoc Series is active.

The substrate visualization shows the arrangement of the fields according to the values set in the Series panel. This feature facilitates the preparation of series exposures. The horizontal fields are for defocus series and the vertical fields represent the dose fields (see below). If the fields overlap, the step size has to be changed to a higher value. If the field arrangement exceeds the substrate surface size, the number of fields has to be reduced.

Select from the options in the Mode dropdown list: Dose, Defoc or Dose and

Defoc.

Set the values required for the selected mode.

Note:

Pay attention to the value in the Total range fields. If the total range requires more space than available on the substrate, an error message pops up.

If desired, activate Auto-Unload (see 6.9 Unload Substrate). Click Start Exposure.

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 The machine is exposing the design. If Auto-Unload

is not activated, then after completion of the

exposure a dialog window pops up asking if the

substrate should be unloaded. Click Yes, if you want

the system to unload the substrate or No if the

substrate should stay loaded on the chuck e. g., to

expose the next layer.

6.8.4 DRAW MODE EXPOSURE PROCEDURE

After creation and submission of the image, you are still in the Draw Mode panel to start the exposure.

In the Draw Mode panel

Set the Dose value by entering the value into the text field. Set the Defoc by selecting the value with the spin buttons (range -10 to 10). The

defoc allows fine tuning of the exposure focus. Optional: Activate Auto-Unload. The system executes the unloading procedure

automatically (see 6.9 Unload Substrate). Click Start Exposure.

 In the Progress Info section the table changes to a list displaying the Draw Mode

procedures that are already executed. The most recent one is listed at the top of

the list. You also find the information about the type of draw mode image and the

coordinates of the center of the image.

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6.9 Unload Substrate

For unloading the substrate the system provides a function called Auto-Unload. This function is selectable by activating a checkbox. Read more in the information below.

Auto-Unload

The Auto-Unload function automatically brings the stage into unloading position directly after exposure completion. Activate the Auto-Unload function by clicking into the checkbox before starting the exposure procedure. Above you see where this checkbox is located in the panels of the different exposure modes (in Draw Mode same location as in First Exposure Mode). After the unloading procedure had finished, the wizard directly leads you back to the Setup Job Panel where you can start a new job with New Job. You can take the substrate from the chuck or leave it there for exposing a further layer.

Unload

Next to the Auto-Unload checkbox there is an Unload button. Alternatively, it is possible to click this button after exposure completion. The stages moves into unloading position. You can take the substrate from the chuck or leave it there for exposing a further layer. To start a new job, go back to Setup Job panel by clicking on the corresponding navigation button.

Figure 14: Unloading options in Standard Mode and Series Mode

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Removing the substrate from the chuck

To remove the substrate from the chuck, follow the steps below:

Push the window button and release it again. The window opens. At the operator panel switch off the vacuum.

Carefully take the substrate off the chuck and stow it in an opaque box

impermeable to light. Close the window by pushing and releasing the button. If required, click OK in the

Exposure Wizard to close the unloading dialog.

Resist coated substrates get useless when exposed to white light!

Non-safe light may only be switched on when all substrates are stored in boxes impermeable to light. Otherwise, the substrates become useless.

Note:

This user guide does not give instructions on substrate processing. Processing of the substrate should happen according to the substrate manufacturer's recommendation.

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The MLA offers further elements beside the main menu that facilitate handling the exposure and alignment processes.

7.1 Control Panel

The Control Panel is a utility that provides navigation functions as well as other necessary control functions.

In the Camera Control frame, the button for selecting the available cameras are arranged. A selection is done by clicking the button for the camera of choice. The camera is then activated. The information about the field of view of the different cameras helps to make the decision which on to choose for the current application. For alignment it is recommended to use the High Res camera as its high resolution is best for alignment procedures

Top Surface

Back Surface

Field of view

Low Res

640 µm x 480

BS Low Res

min. 364 x 274 µm

High Res

190 µm x 140 µm

BS High Res

min.172 x 130 µm

Overview*

20 mm x 20 mm

*Overview cannot access the entire surface of the substrate due to mechanical limits.

Below these you find one Focus slider for setting the camera focus and a Brightness slider for setting the brightness of the camera image.

Click on the slider and keep the mouse button held down while moving it to the desired value on the slider bar. Alternatively, click on the slider bar and use the cursor keys for moving the slider along the bar. The tick marks on the focus slider bar are for your orientation within the range from −10 to +10 so the center tick mark sets the focus to 0.

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A positive number brings the laser focus closer to the surface, exposing deeper into the resist.

The Stage Control frame provides arrow buttons for moving on the substrate surface. Every click is one movement. They are also used for fine positioning.

To determine the kind of movement, you can switch between continuous movement (jogging) and stepwise movement by clicking into the corresponding field. In jog mode, change the driving speed [µm/s] either by using the slider or by clicking into the value field and entering the speed manually. Alternatively, click into the slider field and use the arrow keys for setting the speed. In step mode, enter the step size [µm] for X and Y direction. The arrow buttons for navigation on the substrate surface change their appearance according to the selected mode. This contributes to a fast identification of the mode currently selected.

The Set Zero button allows to set an arbitrary point as zero coordinates. With Move To Zero it is possible to go to the zero point set before. Clicking Substrate Center allows to move the field of view to the center of the substrate. To stop any stage movement, make use of the Stop button.

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7.2 Camera Window

Together with the wizard we provide a camera software that opens in an individual window. The window is only for viewing purposes and is navigable by using the Control Panel (see 7.1 Control Panel). The example below shows the camera window performing a manual alignment.

Figure 15: Camera window

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7.3 Optimizing Alignment and Exposure Results

7.3.1 UNSATISFYING ALIGNMENT MEASUREMENTS

Sometimes the measurements during the alignment process might be unsatisfying due to bad contrast caused by uneven surface conditions or low reflectivity of the substrate. This chapter gives advice how to improve the measurement results during the alignment process.

Repeat the measurement

Clicking Remeasure repeats the measurement procedure which can lead to new results. The Measure button turns into the Remeasure button after the first measurement procedure for one coordinate point.

Change the size of the detection area

For the finding cross function to work properly it is important that the alignment cross fills the entire camera window. If this is not the case, click ResizeDetectionArea. Inside the camera window, a rectangle appears showing the new detection area. To enlarge the detection area, click the right bottom corner of the rectangle without releasing the mouse button and drag the corner to the desired size while holding down the mouse button. To resize the detection area again, click MaximizeDetectionArea.

Change settings in the Control Panel

 Adjust the values for Focus or Brightness to make the finding cross function work

more efficiently.

 Choose a different camera, to get a better view on the substrate.  In the Stage Control Panel, switch between Jog Mode and Step Mode.

Switch to Manual Mode

For every single alignment cross it is possible to switch between the two modes for the alignment procedure. Manual Alignment is the manual mode for cross detection and is provided for exceptional cases in which the automatic detection might not work properly. Switch to Manual Alignment and follow the instructions given in 6.7 Setup Overlay Alignment.

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7.3.2 UNSATISFYING EXPOSURE RESULTS

Sometimes exposure results can be unsatisfying for the needs of distinctive applications. The MLA150 offers a way of optimizing the exposure outcomes. It is possible to adjust the Defoc value or the Dose value. The following section gives details about how to work with these two values in order to improve exposure results.

The Exposure Wizard offers a series exposure mode (6.8.3 Series Exposure Procedure). This utility can be used to optimize exposure results by adjusting the defocus value (Defoc) and/or the energy value (Dose). In order to find the best ratio between these two parameters a series of exposures with different values can be executed.

For more information see the relevant chapter on series exposures.

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7.4 Back Side Alignment

The following section informs about the back side alignment (BSA) preparation and exposure procedure.

7.4.1 OVERVIEW OF BSA MARKER ZONES

The MLA150 comes with a multi-purpose chuck ready to expose both large and small substrates.

For BSA, the chuck provides four designated openings. Markers located in these areas are detected by the BSA camera system and used for alignment.

Each opening is 10 mm wide and 46 mm or 76 mm long. The first edge is located 12 mm or 14.5 mm from the center of the chuck. The BSA markers can be positioned anywhere in this area.

For easy handling and good resolution, Heidelberg Instruments recommends to position the markers on the main axis and about 10 mm from the edge of the wafer. Proposal for marker: cross of size 300 µm x 300 µm, Linewidth 20 µm.

Proposal for marker positions (x/y):

Wafer size

Marker 1 [mm]

Marker 2 [mm]

Marker 3 [mm]

Marker 4 [mm]

2 inch

+20 / 0

-20 / 0

0 / +20

0 / -20

3 inch

+28 / 0

-28 / 0

0 / +28

0 / -28

4 inch

+40 / 0

-40 / 0

0 / +40

0 / -40

5 inch

+44 / 0

-44 / 0

0 / +44

0 / -44

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Figure 16: BSA marker zones overview

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7.4.2 BSA EXPOSURE PREPARATION

Back side alignment is mainly done in two steps. Follow the instructions on the BSA exposure steps

Step 1:

Expose the pattern on side A with the BSA markers. Position your markers inside the BSA marker zones. The

recommended cross linewidth is 20 µm.

Prepare a strategy to find the markers during alignment:

 a larger cross is easier to find  add small marks for orientation

When using the mirror function during design import,

remember to click update to all layers.

Step 2:

After processing of side A, position wafer on chuck with side B on top Remove the inlets of the required BSA holes in the chuck. Define your default marker positions in the MLA150 menu. Select Backside

Camera for this measurement.

Execute alignment exposure as usual.

The coordinate system of the MLA does not change during back side alignment. Reference is always the top of the wafer. This means:

The x-coordinate changes prefix on the back side of the wafer. A marker that was written to position +x is now at position –x. When you use the control panel for movements, the camera picture will move to the left when you click the "to the right" button.

Side A on top

Side B on top

Figure 17: Orientation on wafer for BSA

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This chapter contains some notes on daily maintenance by the operator as well as some troubleshooting for the most common problems. For more in-depth maintenance and troubleshooting information, refer to the related document Maintenance Guide.

8.1 Operator Maintenance

MLA systems require some minimal operator maintenance that does not involve opening any covers or protective panels and can be done by any trained operator. These tasks are described below.

SYSTEM CHECKS

Before operation the following routine maintenance should be performed:

Clean the chuck surface with a dry clean wipe. Never use Acetone! If more

thorough cleaning is required, use industry-grade ethanol or isopropanol. Verify that the clean room conditions are within the limits given in the Technical

Data section. Make sure nothing is placed inside the system that obstructs stage movement

ENVIRONMENTAL ADJUSTMENT

Allow room humidity to come within the specified range before using the MLA150. If temperature is out of range, determine how long this condition has prevailed. Adjust room temperature to within the specified temperature range and allow the

MLA150 to stabilize. For stabilization of the system, allow an amount of time at least equal to the time

the temperature was out of range.

 During exposure, the most accurate results are obtained

when the environment remains at a constant temperature and humidity.

 To achieve the optimum accuracy, the substrate requires

thermal stabilization before exposure. This might take some time depending on the material, thickness and actual temperature.

 The set temperature of the flow box should correspond to

the default room temperature to minimize thermal effects.

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8.2 Troubleshooting

This section suggests corrective action for known issues.

MOUSE DOES NOT MOVE

 Switch on the monitor. The mouse is connected to the monitor. If the monitor is

switched off or in sleep mode, the mouse is inactive as well.

THE MLA150 DOES NOT EXPOSE

 Verify that the AC power cord is plugged into the wall outlet and that the outlet is

receiving power.

 Check whether the laser is switched on and running (see if LED is on).  Verify that the loading window is completely closed.  Try rebooting the system.

LINES NOT TO SIZE

Line thickness problems may have the following causes:

 Poor developing chemicals  Wrong developing speed  Wrong resist type or thickness  Focus or energy setting incorrect  Out of date resist

THE MLA150 STOPS ANYTIME DURING THE EXPOSURE

 The MLA150 reached an end switch because the imaging area was set incorrectly  The interferometer head is broken  The conversion encountered a problem

SUBSTRATES COME OUT COMPLETELY CLEAR

 Laser might be off. Check laser status at LED. If LED is not illuminated, laser is not

running.

BAD ALIGNMENT ACCURACY

 Check stability of flow box temperature  Check vacuum quality, make sure no vibrations are transferred via vacuum  Check stage vibrations  Check for drift in position measurement with stage standing still in home position to

find if interferometer laser has to be replaced

SCRATCH MARKS ON WAFER EDGE

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 Edge beads are not removed. Remove edge beads with the appropriate method to

provide uniform thickness of coating across the wafer.

8.3 TeamViewer Software

On the desktop, you find the icon for the TeamViewer Software. This software enables the service engineer to enter the system via remote connection. It might be possible that the service person asks for the system's access data.

Start TeamViewer QS by clicking on the shortcut icon on the desktop. Pass on the access information to the service person. Both, ID and password are

required.

Note:

Keep in mind that the password is regenerated during the start of TeamViewer QS and differs from the one displayed during the previous start.

HEIDELBERG MLA150 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual