Intel Xeon 5500 Series Design Manual

Intel® Xeon® Processor 5500 Series

Thermal/Mechanical Design Guide

March 2009

Document Number:321323-001

INFORMATION IN THIS DOCUMENT IS PROVIDED IN CONNECTION WITH INTEL® PRODUCTS. NO LICENSE, EXPRESS OR IMPLIED, BY ESTOPPEL OR OTHERWISE, TO ANY INTELLECTUAL PROPERTY RIGHTS IS GRANTED BY THIS DOCUMENT. EXCEPT AS PROVIDED IN INTEL'S TERMS AND CONDITIONS OF SALE FOR SUCH PRODUCTS, INTEL ASSUMES NO LIABILITY WHATSOEVER, AND INTEL DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY, RELATING T O SALE AND/OR USE OF INTEL PRODUCT S INCLUDING LIABILITY OR WARRANTIES RELA TING T O FITNES S FOR A PARTICULAR PURPOSE, MERCHANT ABILITY, OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT. Intel products are not intended for use in medical, life savin g, or life sustaining applications.

Intel may make changes to specifications and product descriptions at any time, without notice. Designers must not rely on the absence or characteristics of any features or instructions marked “reserved” or “undefined.” Intel

reserves these for future definition and shall have no responsibility whatsoev er for conflicts or incompatibilities arising from future changes to them.

The Intel® Xeon® processor 5500 series and LGA1366 socket may contain design defects or errors known as errata which may cause the product to deviate from published specifications. Current characterized errata are available on request.

Contact your local Intel sales office or your distributor to obtain the latest specifications and before placing your product order. Intel processor numbers are not a measure of performance. Processor numb ers differentia te features withi n each processo r family,

not across different processor families. See http://www.intel.com/products/processor_number for details. Over time processor numbers will increment based on changes in clock, speed, cache, FSB, or other features, and increments are not intended to represent proportional or quantitative increases in any particular feature. Current roadmap processor number progression is not necessarily representative of future roadmaps. See www.intel.com/products/processor_number for details.

Intel® Turbo Boost Technology requires a PC with a processor with Intel Turbo Boost Technology capability. Intel Turbo Boost Technology performance varies depending on hardware, software and overall system configuration. Check with your PC manufacturer on whether your system delivers Intel Turbo Boost Technology. For more information, see www.intel.com.

2 Thermal/Mechanical Design Guide

Contents

1Introduction..............................................................................................................9

1.1 References.......................................................................................................10

1.2 Definition of Terms............................................................................................10

2 LGA1366 Socket ......................................................................................................13

2.1 Board Layout....................................................................................................15

2.2 Attachment to Motherboard................................................................................16

2.3 Socket Components...........................................................................................16

2.3.1 Socket Body Housing..............................................................................16

2.3.2 Solder Balls...........................................................................................16

2.3.3 Contacts ...............................................................................................17

2.3.4 Pick and Place Cover...............................................................................17

2.4 Package Installation / Removal ......... ..................................................................18

2.4.1 Socket Standoffs and Package Seating Plane..............................................18

2.5 Durability.........................................................................................................19

2.6 Markings..........................................................................................................19

2.7 Component Insertion Forces ...............................................................................19

2.8 Socket Size ......................................................................................................19

2.9 LGA1366 Socket NCTF Solder Joints.....................................................................20

3 Independent Loading Mechanism (ILM)...................................................................21

3.1 Design Concept.................................................................................................21

3.1.1 ILM Cover Assembly Design Overview.......................................................21

3.1.2 ILM Back Plate Design Overview...............................................................22

3.2 Assembly of ILM to a Motherboard.......................................................................23

4 LGA1366 Socket and ILM Electrical, Mechanical, and Environmental Specifications .27

4.1 Component Mass...............................................................................................27

4.2 Package/Socket Stackup Height ..........................................................................27

4.3 Socket Maximum Temperature............................................................................27

4.4 Loading Specifications.................................... .. .. .. ......................... .. .. .................28

4.5 Electrical Requirements......................................................................................28

4.6 Environmental Requirements .................................................................. ............29

5Thermal Solutions...................................................................................................31

5.1 Performance Targets..........................................................................................31

5.1.1 25.5 mm Tall Heatsink............................................................................33

5.2 Heat Pipe Considerations....................................................................................34

5.3 Assembly .........................................................................................................35

5.3.1 Thermal Interface Material (TIM)..............................................................36

5.4 Structural Considerations ...................................................................................36

5.5 Thermal Design.................................................................................................36

5.5.1 Thermal Characterization Parameter.........................................................36

5.5.2 Dual Thermal Profile ...............................................................................37

5.6 Thermal Features..............................................................................................38

5.6.1 Fan Speed Control..................................................................................39

5.6.2 PECI Averaging and Catastrophic Thermal Management...............................40

5.6.3 Intel® Turbo Boost Technology................................................................40

5.7 Thermal Guidance .............................................................................................40

5.7.1 Thermal Excursion Power for 95 W Processor .............................................40

5.7.2 Thermal Excursion Power for 80 W Processor .............................................41

5.7.3 Absolute Processor Temperature ..............................................................41

Thermal/Mechanical Design Guide 3

6 Quality and Reliability Requirements .......................................................................43

6.1 Test Conditions .................................................................................................43

6.2 Intel Reference Component Validation ..................................................................45

6.2.1 Board Functional Test Sequence ...............................................................45

6.2.2 Post-Test Pass Criteria.............................................................................45

6.2.3 Recommended BIOS/Processor/Memory Test Procedures .............................46

6.3 Material and Recycling Requirements....................................................................46

A Component Su ppliers...............................................................................................47

A.1 Intel Enabled Supplier Information.......................................................................47

A.1.1 Intel Reference Thermal Solution..............................................................47

A.1.2 Intel Collaboration Thermal Solution..........................................................47

A.1.3 Alternative Thermal Solution ....................................................................48

A.1.4 Socket and ILM Components....................................................................49

B Mechanical Drawings ...............................................................................................51

C Socket Mechanical Drawings....................................................................................79

D Heatsink Load Metrology..........................................................................................85

E Embedded Thermal Solutions...................................................................................87

E.1 Performance Targets.................................................. ........................................87

E.2 Thermal Design Guidelines................................ .. ........................... .. ...................88

E.2.1 NEBS Thermal Profile ..............................................................................88

E.2.2 Custom Heat Sinks For UP ATCA...............................................................89

E.3 Mechanical Drawings and Supplier Information......................................................92

F Processor Installation Tool ......................................................................................97

Figures

1-1 Intel® Xeon® 5500 Platform Socket Stack................................................................... 9

2-1 LGA1366 Socket with Pick and Place Cover Removed ....................................................13

2-2 LGA1366 Socket Contact Numbering (Top View of Socket).............................................14

2-3 LGA1366 Socket Land Pattern (Top View of Board) .......................................................15

2-4 Attachment to Motherboard .......................................................................................16

2-5 Pick and Place Cover.................................................................................................17

2-6 Package Installation / Removal Features......................................................................18

2-7 LGA1366 NCTF Solder Joints......................................................................................20

3-1 ILM Cover Assembly ................... .. ................................................... .. .. .. ...................22

3-2 Back Plate ...............................................................................................................23

3-3 ILM Assembly .................... ......................... .. .. .......................... .. .. ......................... ..24

3-4 Pin1 and ILM Lever...................................................................................................25

4-1 Flow Chart of Knowledge-Based Reliability Evaluation Methodology .................................30

5-1 1U Heatsink Performance Curves.................................... .. ..........................................32

5-2 TTV Die Size and Orientation......................................................................................34

5-3 1U Reference Heatsink Assembly................................................................................35

5-4 Processor Thermal Characterization Parameter Relationships..........................................37

5-5 Dual Thermal Profile .................................................................................................38

6-1 Example Thermal Cycle - Actual profile will vary ...........................................................45

B-1 Board Keepin / Keepout Zones (Sheet 1 of 4)...............................................................52

B-2 Board Keepin / Keepout Zones (Sheet 2 of 4)...............................................................53

B-3 Board Keepin / Keepout Zones (Sheet 3 of 4)...............................................................54

B-4 Board Keepin / Keepout Zones (Sheet 4 of 4)...............................................................55

B-5 1U Reference Heatsink Assembly (Sheet 1 of 2) ...........................................................56

B-6 1U Reference Heatsink Assembly (Sheet 2 of 2) ...........................................................57

4 Thermal/Mechanical Design Guide

B-7 1U Reference Heatsink Fin and Base (Sheet 1 of 2) ......................................................58

B-8 1U Reference Heatsink Fin and Base (Sheet 2 of 2) ......................................................59

B-9 Heatsink Shoulder Screw (1U, 2U and Tower)..............................................................60

B-10Heatsink Compression Spring (1U, 2U and Tower)........................................................61

B-11Heatsink Retaining Ring (1U, 2U and Tower) ...............................................................62

B-12Heatsink Load Cup (1U, 2U and Tower).......................................................................63

B-132U Collaborative Heatsink Assembly (Sheet 1 of 2).......................................................64

B-142U Collaborative Heatsink Assembly (Sheet 2 of 2).......................................................65

B-152U Collaborative Heatsink Volumetric (Sheet 1 of 2).....................................................66

B-162U Collaborative Heatsink Volumetric (Sheet 2 of 2).....................................................67

B-17Tower Collaborative Heatsink Assembly (Sheet 1 of 2)..................................................68

B-18Tower Collaborative Heatsink Assembly (Sheet 2 of 2)..................................................69

B-19Tower Collaborative Heatsink Volumetric (Sheet 1 of 2) ................................................70

B-20Tower Collaborative Heatsink Volumetric (Sheet 2 of 2) ................................................71

B-211U Reference Heatsink Assembly with TIM (Sheet 1 of 2)..............................................72

B-221U Reference Heatsink Assembly with TIM (Sheet 2 of 2)..............................................73

B-232U Reference Heatsink Assembly with TIM (Sheet 1 of 2)..............................................74

B-242U Reference Heatsink Assembly with TIM (Sheet 2 of 2)..............................................75

B-25Tower Reference Heatsink Assembly with TIM (Sheet 1 of 2) .................. .. .. ...................76

B-26Tower Reference Heatsink Assembly with TIM (Sheet 2 of 2) .................. .. .. ...................77

C-1 Socket Mechanical Drawing (Sheet 1 of 4)...................................................................80

C-2 Socket Mechanical Drawing (Sheet 2 of 4)...................................................................81

C-3 Socket Mechanical Drawing (Sheet 3 of 4)...................................................................82

C-4 Socket Mechanical Drawing (Sheet 4 of 4)...................................................................83

D-1 Intel® Xeon® Processor 5500 Series Load Cell Fixture.................................................. 86

E-1 ATCA Heatsink Performance Curves............................................................................88

E-2 NEBS Thermal Profile................................................................................................89

E-3 UP ATCA Thermal Solution......... .. .. .......................... .. .. ......................... .. ...................90

E-4 UP ATCA System Layout ............................ .. ......................... ... .. ......................... .. .. ..90

E-5 UP ATCA Heat Sink Drawing ......................................................................................91

E-6 ATCA Reference Heat Sink Assembly (Sheet 1 of 2)......................................................93

E-7 ATCA Reference Heat Sink Assembly (Sheet 2 of 2)......................................................94

E-8 ATCA Reference Heatsink Fin and Base (Sheet 1 of 2)...................................................95

E-9 ATCA Reference Heatsink Fin and Base (Sheet 2 of 2)...................................................96

F-1 Processor Installation Tool.............................. .. .. ... ........................... .. .. .. ...................98

Thermal/Mechanical Design Guide 5

Tables

1-1 Reference Documents ......................................................... .. .......................... .. ........10

1-2 Terms and Descriptions.............................................................................................10

4-1 Socket Component Mass............................................................................................27

4-2 1366-land Package and LGA1366 Socket Stackup Height ...............................................27

4-3 Socket and ILM Mechanical Specifications ....................................................................28

4-4 Electrical Requirements for LGA1366 Socket ................................................................29

5-1 Boundary Conditions and Performance Targets.............................................................31

5-2 Performance Expectations for 25.5 mm Tall Heatsink.....................................................33

5-3 Fan Speed Control, TCONTROL and DTS Relationship ....................................................39

5-4 T

CONTROL

6-1 Heatsink Test Conditions and Qualification Criteria........................................................43

A-1 Suppliers for the Intel Reference Thermal Solution........................................................47

A-2 Suppliers for the Intel Collaboration Thermal Solution ...................................................48

A-3 Suppliers for the Alternative Thermal Solution..............................................................48

A-4 LGA1366 Socket and ILM Components ........................................................................49

B-1 Mechanical Drawing List ............................................................................................51

C-1 Mechanical Drawing List ............................................................................................79

E-1 Boundary Conditions and Performance Targets.............................................................87

E-2 Embedded Heatsink Component Suppliers ...................................................................92

E-3 Mechanical Drawings List...........................................................................................92

Guidance ............. ......................... .. ......................... ... ......................... .. ....39

6 Thermal/Mechanical Design Guide

Revision History

Document Number Revision Number Description Revision Date

321323 001 Public Release March 2009

Thermal/Mechanical Design Guide 7

8 Thermal/Mechanical Design Guide

Introduction

1 Introduction

This document provides guidelines for the design of thermal and mechanical solutions for 2-socket server and 2-socket Workstation processors in the Intel® Xeon® 5500 Platform. The processors covered include those listed in the Intel® Xeon® Processor 5500 Series Datasheet, Volume 1 and the follow-on processors. The design guidelines apply to the follow-on processors in their current stage of development and are not expected to change as they mature. The components described in this document include:

• The processor thermal solution (heatsink) and associated retention hardware.

• The LGA1366 socket and the Independent Loading Mechanism (ILM) and back plate.

Processors in 1-socket Workstation platforms are covered in the Intel® Xeon® Processor 3500 Series Thermal/Mechanical Design Guide.

Figure 1-1. Intel® Xeon® 5500 Platform Socket Stack

Heatsink

Socket and IL M

Back Plate

The goals of this document are:

• To assist board and system thermal mechanical designers.

• To assist designers and suppliers of processor heatsinks.

Thermal profiles and other processor specifications are provided in the Datasheet.

Thermal/Mechanical Design Guide 9

1.1 References

Material and concepts available in the following documents may be beneficial when reading this document.

Table 1-1. Reference Documents

Document Location Notes

European Blue Angel Recycling Standards 2 Intel® Xeon® Processor 5500 Series Datasheet, Volume 1 321321 1 Intel® Xeon® Processor 5500 Series Mechanical Model 321326 1 Intel® Xeon® Processor 5500 Series Thermal Model 321327 1 Entry-level Electronics Bay Specification 3

Notes:

1. Document numbers indicated in Location column are subject to change. See the appropriate Electronic Design Kit (EDK) for the most up-to-date Document number.

2. Available at http://www.blauer-engel.de

3. Available at http://ssiforum.oaktree.com/

Introduction

1.2 Definition of Terms

Table 1-2. Terms and Descriptions (Sheet 1 of 2)

Term Description

Bypass Bypass is the area between a passive heatsink and any object that can act to form a

DTS Digital Thermal Sensor reports a relative die temperature as an offset from TCC

FSC Fan Speed Control IHS Integrated Heat Spreader: a component of the processor pac k age used to enhance the

ILM Independent Loading Mechanism provides the force needed to seat the 1366-LGA land

LGA1366 socket The processor mates with the system board through this surface mount, 1366-contact

PECI The Platform Environment Control Interface (PECI) is a one- wire in terface that pro vides

CASE

CASE_MAX

TCC Thermal Control Circuit: Thermal monitor uses the TCC to reduce the die temperature

duct. For this example, it can be expressed as a dimension away from the outside dimension of the fins to the nearest surface.

activation temperature.

thermal performance of the package. Component thermal solutions interface with the processor at the IHS surface.

package onto the socket contacts.

socket.

a communication channel between Intel processor and chipset components to external monitoring devices.

Case-to-ambient thermal characterization parameter (psi). A measure of thermal solution performance using t otal package power. Defined as (T Package Power. Heat source should always be specified for Ψ measurements.

Case-to-sink thermal characterization parameter. A measure of thermal interface material performance using total package po wer. Defined as (T Package Power.

Sink-to-ambient thermal characterization parameter. A measure of heatsink thermal performance using total package power. Defined as (T

The case temperature of the processo r measured at the geom etric ce nter of the t opside of the IHS.

The maximum case temperature as specified in a component specification.

by using clock modulation and/or operating frequency and input voltage adjustment when the die temperature is very near its operating limits.

– TLA) / Total

CASE

– TS) / Total

CASE

– TLA) / Total Package Power.

10 Thermal/Mechanical Design Guide

Introduction

Table 1-2. Terms and Descriptions (Sheet 2 of 2)

Term Description

CONTROL

TDP Thermal Design Power: Thermal solution should be designed to dissipate this target

Thermal Monitor A power reduction feature designed to decrease temperature after the processor has

Thermal Profile Line that defines case temperature specification of a processor at a given power level. TIM Thermal Interface Material: The thermally conductive compound between the heatsink

U A unit of measure used to define server rack spacing height. 1U is equal to 1.75 in, 2U

T control.

power level. TDP is not the maximum power that the processor can dissipate.

reached its maximum operating temperature.

and the processor case. This material fills the air gaps and voids, and enhances the transfer of the heat from the processor case to the heatsink.

The measured ambient temperature locally surrounding the proces sor. The ambient temperature should be measured just upstream of a p assive he atsink or at the fan inle t for an active heatsink.

The system ambient air temperature external to a system chassis. This temperature is usually measured at the chassis air inlets.

equals 3.50 in, etc.

is a static value below TCC activation used as a trigger point for fan speed

CONTROL

Thermal/Mechanical Design Guide 11

Introduction

12 Thermal/Mechanical Design Guide

LGA1366 Socket

2 LGA1366 Socket

This chapter describes a surface mount, LGA (Land Grid Array) socket intended for processors in the Intel® Xeon® 5500 Platform. The socket provides I/O, power and ground contacts. The socket contains 1366 contacts arrayed about a cavity in the center of the socket with lead-free solder balls for surface mounting on the motherboard.

The socket has 1366 contacts with 1.016 mm X 1.016 mm pitch (X by Y) in a 43x41 grid array with 21x17 grid depopulation in the center of the array and selective depopulation elsewhere.

The socket must be compatible with the package (processor) and the Independent Loading Mechanism (ILM). The design includes a back plate which is integral to having a uniform load on the socket solder joints. Socket loading specifications are listed in

Chapter 4.

Figure 2-1. LGA1366 Socket with Pick and Place Cover Removed

package socket

package

cavity

socket

Thermal/Mechanical Design Guide 13

Figure 2-2. LGA1366 Socket Contact Numbering (Top View of Socket)

31 29 27 25 23 21 19 17 15 13 11 9 7 5

32 30 28 26 24 22 20 18 16 14 12 10 8 6 4

LGA1366 Socket

43 41 39 37 35 33 31 29 27 25 23 21 19 17 15 13

42 40 38 36 34 32 30 28 26 24 22 20 18 16 14 12

14 Thermal/Mechanical Design Guide

LGA1366 Socket

2.1 Board Layout

The land pattern for the LGA1366 socket is 40 mils X 40 mils (X by Y), and the pad size is 18 mils. Note that there is no round-off (conversion) error between socket pitch (1.016 mm) and board pitch (40 mil) as these values are equivalent.

Figure 2-3. LGA1366 Socket Land Pattern (Top View of Board)

A C E G J L N R U W AA AC AE AG AJ AL AN AR AU AW BA

B D F H K M P T V Y AB AD AF AH AK AM AP AT AV AY

A C E G J L N R U W AA AC AE AG AJ AL AN AR AU AW BA

B D F H K M P T V Y AB AD AF AH AK AM AP AT AV AY

Thermal/Mechanical Design Guide 15

2.2 Attachment to Motherboard

The socket is attached to the motherboard by 1366 solder balls. There are no additional external methods (that is, screw, extra solder, adhesive, and so on) to attach the socket.

As indicated in Figure 2-4, the Independent Loading Mechanism (ILM) is not present during the attach (reflow) process.

Figure 2-4. Attachment to Motherboard

LGA1366 Socket

ILM

LGA 1366 Socket

2.3 Socket Components

The socket has two main components, the socket body and Pick and Place (PnP) cover, and is delivered as a single integral assembly. Refer to Appendix C for detailed drawings.

2.3.1 Socket Body Housing

The housing material is thermoplastic or equivalent with UL 94 V -0 flame rating capable of withstanding 260 °C for 40 seconds (typical reflow/rework). The socket coefficient of thermal expansion (in the XY plane), and creep properties, must be such that the integrity of the socket is maintained for the conditions listed in the LGA1366 Socket Validation Re ports.

The color of the housing will be dark as compared to the solder balls to provide the contrast needed for pick and place vision systems.

2.3.2 Solder Balls

A total of 1366 solder balls corresponding to the contacts are on the bottom of the socket for surface mounting with the motherboard.

The socket has the following solder ball material:

• Lead free SAC (SnAgCu) solder alloy with a silver (Ag) content between 3% and 4% and a melting temperature of approximately 217 °C. The alloy must be compatible with immersion silver (ImAg) motherboard surface finish and a SAC alloy solder paste.

16 Thermal/Mechanical Design Guide

LGA1366 Socket

The co-planarity (profile) and true position requirements are defined in Appendix C.

2.3.3 Contacts

Base material for the contacts is high strength copper alloy. For the area on socket contacts where processor lands will mate, there is a 0.381 μm

[15 μinches] minimum gold plating over 1.27 μm [50 μinches] minimum nickel underplate.

No contamination by solder in the contact area is allowed during solder reflow.

2.3.4 Pick and Place Cover

The cover provides a planar surface for vacuum pick up used to place components in the Surface Mount Technology (SMT) manufacturing line. The cover remains on the socket during reflow to help prevent contamination during reflow. The cover can withstand 260 °C for 40 seconds (typical reflow/rework profile) and the conditions listed in the LGA1366 Socket Validation Reports without degrading.

As indicated in Figure 2-5, the cover remains on the socket during ILM installation, and should remain on whenever possible to help prevent damage to the socket contacts.

Cover retention must be sufficient to support the socket weight during lifting, translation, and placement (board manufacturing), and during board and system shipping and handling.

The covers are designed to be interchangeable between socket suppliers. As indicated in Figure 2-5, a Pin1 indicator on the cover provides a visual reference for proper orientation with the socket.

Figure 2-5. Pick and Place Cover

ILM

Installation

Pin 1 Pin 1

Thermal/Mechanical Design Guide 17

Pick and

Place Cover

2.4 Package Installation / Removal

As indicated in Figure 2-6, access is provided to facilitate manual installation and removal of the package.

To assist in package orientation and alignment with the socket:

• The package Pin1 triangle and the socket Pin1 chamfer provide visual reference for proper orientation.

• The package substrate has orientation notches along two opposing edges of the package, offset from the centerline. The socket has two corresponding orientation posts to physically prevent mis-orientation of the package. These orientation features also provide initial rough alignment of package to socket.

• The socket has alignment walls at the four corners to provide final alignment of the package.

See Appendix F for information regard ing a tool designed to provide mechanical

Figure 2-6. Package Installation / Removal Features

assistance during processor installation and removal.

LGA1366 Socket

orientation

orientation notch

notch

alignment

Pin1 triangle

access

orientation

orientation post

post

Pin1 chamfer

alignment walls

walls

2.4.1 Socket Standoffs and Package Seating Plane

Standoffs on the bottom of the socket base establish the minimum socket height after solder reflow and are specified in Appendix C.

Similarly, a seating plane on the topside of the socket establishes the minimum package height. See Section 4.2 for the calculated IHS height above the motherboard.

18 Thermal/Mechanical Design Guide

LGA1366 Socket

2.5 Durability

The socket must withstand 30 cycles of processor insertion and removal. The max chain contact resistance from Table 4-4 must be met when mated in the 1st and 30th cycles.

The socket Pick and Place cover must withstand 15 cycles of insertion and removal.

2.6 Markings

There are three markings on the socket:

• LGA1366: Font type is Helvetica Bold - minimum 6 point (2.125 mm).

• Manufacturer's insignia (font size at supplier's discretion).

• Lot identification code (allows traceability of manufacturing date and location).

All markings must withstand 260 °C for 40 seconds (typical reflow/rework profile) without degrading, and must be visible after the socket is mounted on the motherboard.

LGA1366 and the manufacturer's insignia are molded or laser marked on the side wall.

2.7 Component Insertion Forces

Any actuation must meet or exceed SEMI S8-95 Safety Guidelines for Ergonomics/ Human Factors Engineering of Semiconductor Manu facturing Equipment, example Table R2-7 (Maximum Grip Forces). The socket must be designed so that it requires no force to insert the package into the socket.

2.8 Socket Size

Socket information needed for motherboard design is given in Appendix C. This information should be used in conjunction with the reference motherboard keep-

out drawings provided in Appendix B to ensure compatibility with the reference thermal mechanical components.

Thermal/Mechanical Design Guide 19

2.9 LGA1366 Socket NCTF Solder Joints

Intel has defined selected solder joints of the socket as non-critical to function (NCTF) for post environmental testing. The processor signals at NCTF locations are typically redundant ground or non-critical reserved, so the loss of the solder joint continuity at end of life conditions will not affect the overall product functionality. Figure 2-7

Figure 2-7. LGA1366 NCTF Solder Joints

identifies the NCTF solder joints.

A C E G J L N R U W AA AC AE AG AJ AL AN AR AU AW BA

B D F H K M P T V Y AB AD AF AH AK AM AP AT AV AY

A C E G J L N R U W AA AC AE AG AJ AL AN AR AU AW BA

B D F H K M P T V Y AB AD AF AH AK AM AP AT AV AY

LGA1366 Socket

Note: For platforms supporting the DP processor land C3 is CTF.

20 Thermal/Mechanical Design Guide

Independent Loading Mechanism (ILM)

3 Independent Loading

Mechanism (ILM)

The Independent Loading Mechanism (ILM) provides the force needed to seat the 1366-LGA land package onto the socket contacts. The ILM is physically separate from the socket body. The assembly of the ILM to the board is expected to occur after wave solder. The exact assembly location is dependent on manufacturing preference and test flow.

Note: The ILM has two critical functions: deliver the force to seat the processor onto the

socket contacts and distribute the resulting compressive load evenly through the socket solder joints.

Note: The mechanical design of the ILM is integral to the overall functionality of the LGA1366

socket. Intel performs detailed studies on integration of processor package, socket and ILM as a system. These studies directly impact the design of the ILM. The Intel reference ILM will be “build to print” from Intel controlled drawings. Intel recommends using the Intel Reference ILM. Custom non-Intel ILM designs do not benefit from Intel's detailed studies and may not incorporate critical design parameters.

3.1 Design Concept

The ILM consists of two assemblies that will be procured as a set from the enabled vendors. These two components are ILM cover assembly and back plate.

3.1.1 ILM Cover Assembly Design Overview

The ILM Cover assembly consists of four major pieces: load lever, load plate, frame and the captive fasteners.

The load lever and load plate are stainless steel. The frame and fasteners are high carbon steel with appropriate plating. The fasteners are fabricated from a high carbon steel. The frame provides the hinge locations for the load lever and load plate.

The cover assembly design ensures that once assembled to the back plate and the load lever is closed, the only features touching the board are the captive fasteners. The nominal gap of the frame to the board is ~1 mm when the load plate is closed on the empty socket or when closed on the processor package.

When closed, the load plate applies two point loads onto the IHS at the “dimpled” features shown in Figure 3-1. The reaction force from closing the load plate is transmitted to the frame and through the captive fasteners to the back plate. Some of the load is passed through the socket body to the board inducing a slight compression on the solder joints.

Thermal/Mechanical Design Guide 21

Figure 3-1. ILM Cover Assembly

Load Lever

Load Plate

Independent Loading Mechanism (IL M )

Captive Fastener (4x)

Frame

3.1.2 ILM Back Plate Design Overview

The unified back plate for 2-socket server and 2-socket Workstation products consists of a flat steel back plate with threaded studs for ILM attach, and internally threaded nuts for heatsink attach. The threaded studs have a smooth surface feature that provides alignment for the back plate to the motherboard for proper assembly of the ILM around the socket. A clearance hole is located at the center of the plate to allow access to test points and backside capacitors. An additional cut-out on two sides provides clearance for backside voltage regulator components. An insulator is preapplied.

Back plates for processors in 1-socket Workstation platforms are covered in the Intel® Xeon® Processor 3500 Series Thermal/Mechanical Design Guide.

22 Thermal/Mechanical Design Guide

Independent Loading Mechanism (ILM)

Figure 3-2. Back Plate

Threaded studs

Clearance hole

Threaded nuts

3.2 Assembly of ILM to a Motherboard

The ILM design allows a bottoms up assembly of the components to the board. In step 1, (see Figure 3-3), the back plate is placed in a fixture. Holes in the motherboard provide alignment to the threaded studs. In step 2, the ILM cover assembly is placed over the socket and threaded studs. Using a T20 Torx* driver fasten the ILM cover assembly to the back plate with the four captive fasteners. Torque to 8 ± 2 inchpounds. The length of the threaded studs accommodate board thicknesses from

0.062” to 0.100”.

Thermal/Mechanical Design Guide 23

Figure 3-3. ILM Assembly

Independent Loading Mechanism (IL M )

Step 1: W ith so c k et b ody reflowe d on

Step 1: W ith so c k et b ody reflowe d on board, and back plate in fixture, align

board, and back plate in fixture, align board holes to back plate studs.

board holes to back plate studs.

Step 2: With back plate against bottom of

Step 2: With back plate against bottom of board, align ILM cover assembly to back

board, align ILM cover assembly to back plate studs.

plate studs.

24 Thermal/Mechanical Design Guide

Independent Loading Mechanism (ILM)

As indicated in Figure 3-4, socket protrusion and ILM key features prevent 180-degree rotation of ILM cover assembly with respect to the socket. The result is a specific Pin 1 orientation with respect to the ILM lever.

Figure 3-4. Pin1 and ILM Lever

Protrusion

ILM Key

ILM Lever

Pin 1

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Independent Loading Mechanism (IL M )

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LGA1366 Socket and ILM Electrical, Mechanical, and Environmental Specifications

4 LGA1366 Socket and ILM

Electrical, Mechanical, and Environmental Specifications

This chapter describes the electrical, mechanical, and environmental specifications for the LGA1366 socket and the Independent Loading Mechanism.

4.1 Component Mass

Table 4-1. Socket Component Mass

Component Mass

Socket Body, Contacts and PnP Cover 15 gm ILM Cover 43 gm ILM Back Plate for dual processor server products 100 gm

4.2 Package/Socket Stackup Height

Table 4-2 provides the stackup height of a processor in the 1366-land LGA package and

LGA1366 socket with the ILM closed and the processor fully seated in the socket.

Table 4-2. 1366-land Package and LGA1366 Socket Stackup Height

Integrated Stackup Height (mm) From Top of Board to Top of IHS

Notes:

1. This data is provided for information only , and shou ld be deri v ed from: (a) the h eight of the s ocke t seating plane above the motherboard after reflow, given in Appendix C, (b) the height of the package, from the package seating plane to the top of the IHS, and accounting for its nominal variation and tolerances that are given in the corresponding processor EMTS.

2. This value is a RSS calculation.

7.729 ± 0.282 mm

4.3 Socket Maximum Temperature

The power dissipated within the socket is a function of the current at the pin level and the effective pin resistance. To ensure socket long term reliability, Intel defines socket maximum temperature using a via on the underside of the motherboard. Exceeding the temperature guidance may result in socket body deformation, or increases in thermal and electrical resistance which can cause a thermal runaway and eventual electrical failure. The guidance for socket maximum temperature is listed below:

• Via temperature under socket < 96 °C

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LGA1366 Socket and ILM Electrical, Mechanical, and Environmental Specifications

4.4 Loading Specifications

The socket will be tested against the conditions listed in the LGA1366 Socket Validation Reports with heatsink and the ILM attached, under the loading conditions outlined in this chapter.

Table 4-3 provides load specifications for the LGA1366 socket with the ILM installed.

The maximum limits should not be exceeded during heatsink assembly, shipping conditions, or standard use condition. Exceeding these limits during test may result in component failure. The socket body should not be used as a mechanical reference or load-bearing surface for thermal solutions.

Table 4-3. Socket and ILM Mechanical Specifications

Parameter Min Max Notes

Static compressive load from ILM cover to processor IHS

Heatsink Static Compressive Load 0 N [0 lbf] 266 N [60 lbf] 1, 2, 3 Total Static Compressive Load

(ILM plus Heatsink) Dynamic Compressive Load

(with heatsink installed) Pick and Place Cover Insertion / Removal force N/A 10.2 N [2.3 lbf] Load Lever actuation force N/A 38.3 N [8.6 lbf] in the

470 N [106 lbf] 623 N [140 lbf] 3, 4

470 N (106 lbf) 890 N (200 lbf) 3, 4

N/A 890 N [200 lbf] 1, 3, 5, 6

vertical direction

10.2 N [2.3 lbf] in the lateral direction.

Notes:

1. These specifications apply to uniform compressive loading in a direction perpendicular to the IHS top surface.

2. This is the minimum and maximum static force that can be applied by the heatsink and it’s retention solution to maintain the heatsink to IHS interface. This does not imply the Intel reference TIM is validated to these limits.

3. Loading limits are for the LGA1366 socket.

4. This minimum limit defines the compress ive forc e required to electrically seat the processor onto the sock et contacts.

5. Dynamic loading is defined as an 11 ms duration average load superimposed on the static load requirement.

6. T est condition used a heatsink mass of 550 gm [1.21 lb] with 50 g acceler ation measured at heatsi nk mass. The dynamic portion of this specification in the product application can have flexibility in specific values, but the ultimate product of mass times acceleration should not exceed this dynamic load.

4.5 Electrical Requirements

LGA1366 socket electrical requirements are measured from the socket-seating plane of the processor to the component side of the socket PCB to which it is attached. All specifications are maximum values (unless otherwise stated) for a single socket contact, but includes effects of adjacent contacts where indicated.

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LGA1366 Socket and ILM Electrical, Mechanical, and Environmental Specifications

Table 4-4. Electrical Requirements for LGA1366 Socket

Parameter Value Comment

Mated loop inductance, Loop

Mated partial mutual inductance, L

Maximum mutual capacitance, C. Socket Average Contact R esistance

(EOL)

Max Individual Contact Resistance (EOL)

Bulk Resistance Increase

Dielectric Withstand Voltage Insulation Resistance

<3.9nH

<1 pF

15.2 mΩ

≤ 100 mΩ

≤ 3 mΩ

360 Volts RMS

800 MΩ

The inductance calculated for two contacts, considering one forward conductor an d one return conductor. These values must be satisfied at the worst-case height of the socket.

The inductance on a contact due to any single neighboring contact.

The capacitance between two contacts The socket average contact resistance target is

derived from average of every chain contact resistance for each part used in testing, with a chain contact resistance defined as the resistance of each chain minus resistance of shorting bars divided by number of lands in the daisy chain.

The specification listed is at room temperature and has to be satisfied at all time.

Socket Contact Resistance: The resistance of the socket contact, solderball, and interface resistance to the interposer land.

The specification listed is at room temperature and has to be satisfied at all time.

Socket Contact Resistance: The resistance of the socket contact, solderball, and interface resistance to the interposer land; gaps included.

The bulk resistance increase per contact from 24 °C to 107 °C

4.6 Environmental Requirements

Design, including materials, shall be consistent with the manufacture of units that meet the following environmental reference points.

The reliability targets in this chapter are based on the expected field use environment for these products. The test sequence for new sockets will be developed using the knowledge-based reliability evaluation methodology, which is acceleration factor dependent. A simplified process flow of this methodology can be seen in Figure 4-1.

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LGA1366 Socket and ILM Electrical, Mechanical, and Environmental Specifications

Figure 4-1. Flow Chart of Knowledge-Based Reliability Evaluation Methodology

Establish the market/expected use environment for the technology

Develop Speculative stress conditions based on historical data, content experts, and literature search

Freeze stressing requirements and perform additional data turns

Perform stressing to validate accelerated stressing assumptions and determine acceleration factors

A detailed description of this methodology can be found at:

ftp://download.intel.com/technology/itj/q32000/pdf/reliability.pdf.

30 Thermal/Mechanical Design Guide

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