burn-in & test socket workshop - testconx · professional services are needed costly-1. page 7...

March 4 - 7, 2001Hilton Mesa Pavilion Hotel

Mesa, Arizona

Sponsored By The IEEE Computer SocietyTest Technology Technical Council

Burn-in & TestSocket Workshop

IEEE IEEE

COMPUTERSOCIETY

COPYRIGHT NOTICE• The papers in this publication comprise the proceedings of the 2001BiTS Workshop. They reflect the authors’ opinions and are reproduced aspresented , without change. Their inclusion in this publication does notconstitute an endorsement by the BiTS Workshop, the sponsors, or theInstitute of Electrical and Electronic Engineers, Inc.· There is NO copyright protection claimed by this publication. However,each presentation is the work of the authors and their respectivecompanies: as such, proper acknowledgement should be made to theappropriate source. Any questions regarding the use of any materialspresented should be directed to the author/s or their companies.

Session 7Wednesday 3/07/01 8:00AM

Advancements In Socket Products

PASS ChipMin Cho Inabata America Corporation

Evaluating Elastomer For High Density BGA SocketIla Pal - Ironwood Electronics, Inc.

Low Cost Thermal Management Using Compliant Thermal Interface MaterialsNancy Dean Honeywell Electronic Materials (Presenter)

Kenichiro Fukuyama - Honeywell Electronic Materials

Technical Program

2001 Burn-in and Test Socket Workshop 2001 Burn-in and Test Socket Workshop

Manufactured by

Corporation

PASS CHIPPASS CHIPPASS CHIP

Distributed by

Corporation Inabata America

March 4 - 7, 2001

Presented By : Min Cho

inabatainabatainabatainabatainabatainabatainabatainabatainabatainabatainabatainabata

MissionBased on years of experience and survey, we havesuccessfully invented the most effective, simple, and leastcostly tools for electrical contact cleaning: PASS CHIPproducts.

To be a unique providerof the best solution for thecontact problems whichinevitably arise with allkinds of electronic devicesto be seen everywheretoday.

To contribute toward moreproductivity yielded by moreeffective and less costly productionin the electronics industriesworldwide, resulting in higherquality goods and higher cost-performance that can morecomfortably surround and furtherenrich the daily lives of people.


Market Outlook -1The following facts will dramatically expand the market of contact cleaners.

Semiconductors are in huge demand

The IT revolution iscreating a large varietyof applications ofpowerful semiconductorproducts.

PCs, Mobile Phones,Video Cameras, DVDplayers, CommunicationDevices, HomeAppliances, etc...

Estimation of monthly worldwideproduction of semiconductors

Year 2000 2003 2005Number of Unit 30,000 60,000 100,000(in Millions)

This creates a need for morefrequent contact cleaning!

inabatainabatainabatainabatainabatainabatainabatainabata

Market Outlook -2Lighter, more compact packages of semiconductorswill inevitably follow.

It is a fact: Electronic commodity goods areproduced lighter, more compact, more ergonomicwith each new generation. Newer types ofsemiconductors, such as FBGA & CSP willbecome more prevalent.

This creates the need for more advancedcontact cleaning methods.


Market Outlook -3More productivity and more effectiveness inevery process of production are needed

As the usage of mass-production increases, our testingprocess must become more effective.An efficient contact cleaning operation should be easily donewithout a burden of cost.

This creates the need for an easier &cheaper method for contact cleaning


Before

Ultrasonic-Wave cleaningThe outside cleaning companyusually needs 4-5 days for cleaningtime, and this requires substitutes ofburn-in or final testing board

Costly, time consuming,troublesome in-outhandling

PASS CHIPPASS CHIPPASS CHIPPASS CHIPPASS CHIPPASS CHIPPASS CHIPPASS CHIPThe semiconductor industry has been looking for abetter solution of contact cleaning for years.The following methods of contact cleaning arecurrently widely used:

Professional services are needed

Costly

-1


Before

Brush cleaningManual brushing takes alot of time

Time consuming,less productive

PASS CHIPPASS CHIPPASS CHIPPASS CHIPPASS CHIPPASS CHIPPASS CHIPPASS CHIP

Air blow cleaningSolder residues cannotalways be completelyremoved

Less effective

-2


Before

Replacement of contact pins instead of cleaning

Re-manufacturing thecontact pins is costly

Expensive


Replacing the pinsrequires a professionalservice

Costly, time consuming

-3


With

Proven effectiveness in cleaning


" PASS CHIP " has created a perfect solution forcontact cleaning to eliminate all sort of headachesthat keep annoying production managers.

Major manufacturers in the semiconductor industry havethoroughly evaluated "PASS CHIP" models and been wellsatisfied with its effectiveness in cleaning.

-1


With PASS CHIPPASS CHIPPASS CHIPPASS CHIPPASS CHIPPASS CHIPPASS CHIPPASS CHIP

Evaluation Test of Cleaning operation

Package Used : TSOP2

Burn-in Boards : 48 sockets x 66boards

Evaluation method :

-2

Comparedoccurrence ofdefective devicesbefore and afterPASS Chipapplication


With PASS CHIPPASS CHIPPASS CHIPPASS CHIPPASS CHIPPASS CHIPPASS CHIPPASS CHIP

Evaluation Test Results (66 Boards) Before Cleaning After Cleaning

Board Good Defective Ratio Good Defective Ratio1 42 6 12.5% 48 0 0.0%2 42 6 12.5% 48 0 0.0%3 45 3 6.3% 48 0 0.0%4 46 2 4.2% 47 1 2.1%5 43 5 10.4% 47 1 2.1%6 44 4 8.3% 48 0 0.0%7 40 8 16.7% 47 1 2.1%

64 37 11 22.9% 45 3 6.3%65 39 9 18.8% 46 2 4.2%66 43 5 10.4% 48 0 0.0%

Total 2667 503 15.9% 3109 59 1.8%

-3


With

Ease of usage


"PASS CHIP" can be easily placed on the contact pinsmanually or by a vacuum pad, and requires NO professionalservices for effective cleaning.

Low cost

Cleaning your contactors with a disposable "PASS CHIP"requires no additional costs.

-4


With

Short cleaning time


One or two wipes with "PASS CHIP" can instantlyremove the solder residues or dirt from the contactpins, which results in shorter down time and a moreproductive testing process.

-5

1. Flat sheet model for TSOP / QFP type of socket(Single coated or Double coated)

2. Cubic sheet model for TSOP / QFP type of socket

3. Pad model for CSP / BGA type of socket


Products for IC Socket contact cleaning


Useful both in a burn-in and a final test process as well as in awriting process of SRAM or Flash Me

Products-1

Available to any type of socket, i.e. OPENTOP, LID or LIDLESS.

Available to any customer specifications.


Product for Probe Card contact cleaning


Available to any customer specifications

Products-2

Product for DIMM contact cleaningAvailable to any customer specifications

1

Evaluating Elastomerfor High Density BGA

Socket

Ila Pal

2

Agenda Socket design Tolerance analysis Elastomer properties Electrical characteristics Mechanical characteristics Transmission line theory Conclusions

3

Socket Design

Socket Base

Target P CB with S MT pads

SocketTop Assembly

Compression Screw

Compression plate

BGA Package

Z-Axis Elastomer

Machine Screw

Socket Lid

Machine Screw

Alignment plate

4

Alignment Plate Design

A

C

B

D

FE

A = Ball diameterB = Hole to edge of alignment plateC = Hole to PCB padD = PCB pad to PCB padE = Ball to ballF = Edge of ball to edge of alignment plate

Alignment plate

Solder ball

PCB pad

5

Z-Axis Conductive Wire on Elastomer

Low-resistance (<0.01Ω) connector 30 Micron diameter gold plated brass wires Wire density - 0.1mm or less 63° angled wire embedded in silicone Insulation resistance: 1000 MΩ @500V DC 50mA per filament Operating temperature: -35° to 100° C

6

SEM Picture of Elastomer

7

Solder Ball on Elastomer

0.75mm

8

Elastomer before Compression

9

Elastomer after Compression

10

Surface Effect on Solder Ball

11

Resistance Test Setup

R

Gold plated pin electrode

Elastomer

Test board

Compress

Gold plated pin electrode

HP 4338A

12

Compression Vs Resistance

0 10 2030 40 50 60 70 80

100

0.0 0.1 0.2 0.3 0.4 0.5

Compression (mm)

Cont

inui

ty R

esist

ance

(mΩ

)

2.0 T

1.0 T

0.5 T

13

Compression Load Test Setup

Compression point

Load Cell Compression rate 0.5mm/min

Flat boards

Elastomer

Compression length = T Compression Load

14

Compression Vs Load

0 20 40 60 80

100 120 140 160 180

0 0.05 0.1 0.15 0.2 0.25 0.3 35 0.4 0.45 0.5

Compression (mm)

Com

pres

sion

Load

(gf/

mm

2 )

0.5 T

1.0 T

2.0 T

15

Reliability Test Setup

0.5mm round Gold plated pin

Au Plated Electrode

Elastomer thickness 1mm

Compression 0.3mm

R

Compression cycle

Compression 1 Sec

Open 1 Sec

16

Endurance Characteristics

-100

-80

-60

-40

-20

0

20

40

60

80

100

1 20000 40000 60000 80000 100000 The number of Compression

Cha

nge

of R

esist

ance

(mΩ

)

17

Test Setup for Measuring Current

φ1.0mm Au plated electrode

Au sheet electrode

Thermal couple Elastomer

Compress

18

Current Carrying Capacity

25 26 27 28 29

30 31 32 33 34 35

0 1 2 3 4 5 6 7 8 9 10 Time (min)

Tem

pera

ture

(deg

C)

10.0A 5.0A

19

Transmission Line Types

PARALLEL-PLATE TRANSMISSION LINE

TWO-WIRE TRANSMISSION LINE COAXIAL TRANSMISSION LINE

2a

2bD

2a

w

d

20

Equivalent Circuit of Transmission Line

+

-∆ z

v (z , t )

R L

CG

∆ z

∆ z∆ z

∆ z

i( z , t) i ( z + , t)∆ z

v ( z + , t)∆ z

P a r a m e t e r P a r a lle l- P la te L in e

T w o - W ir e L in e C o a x ia l L in e U n it

R sR

w2

πaR s

+ba

R s 112π

Ω /m

L wd

µ

πµ

c o sh -1

aD2

πµ

2ln

ab

H /m

G dw

σ πσ

c o sh -1

aD2

2 π σ

ln

ab

S /m

C dw

∈ π ∈

c o sh -1

aD2

2 π ∈

ln

ab

F /m

Source: Fundamentals of Engineering Electromagnetics - David K. Cheng

21

Results

For 0.3mm thick elastomer: Capacitance = 0.006 pF Inductance = 0.06 nH Resistance < 0.010 Ω

22

Surface Mount Socket

Solderless Socket

23

Conclusions Simple design of socket Easy manufacturability of components Better electrical and mechanical characteristics Low compression force per solder ball Damage free solder balls Fast, dense and durable High frequency IC prototyping applications Field upgradeable systems applications

ITherm20005/24/00

NFD

Low Cost Thermal Management using Compliant Thermal Interface Materials

Nancy DeanKenichiro Fukuyama

Honeywell Electronic Materials

BiTS20011/05/01

SIA Roadmap - Projected Power Dissipation

0255075

100125150175200

1995 2000 2005 2010 2015

Sing

le C

hip

Pack

age

Pow

er (W

)

Cost PerformanceHigh Performance

Power Dissipation at Burn-in and Test increases

- Thermal Management becomes more of an issue.

BiTS20011/05/01

Thermal Resistance Calculations

Die (device)

Heat Sink

Tjunction

Tambient

THS base

Tdie backside

θHeat Sink

θInterface

θDie

Total Thermal Resistance =(Tjunction - Tambient)/Power

High interface thermal resistance means Heat Sink thermalresistance must be lower (i.e., heat sink larger or more expensive)

BiTS20011/05/01

Heat Sink Thermal Resistance

As a general rule, heat transfer from a heat sinkscales with fin area.

Heat spreading on heat sink base becomesimportant for large heat sinks.

High density fins (large number of tall fins per unitlength) can be expensive to manufacture.

Want to minimize heat sink size to allow greaterpacking of sockets.

Lowering thermal resistance in the rest of thesystem allows a less expensive heat sink to beused.

BiTS20011/05/01

Why is an Interface Material Needed?

< 2% of area is in metal tometal contact, even forvery smooth surfaces.

Heat conduction acrossair gap is poor.

Real Surfaces are not smooth

BiTS20011/05/01

Why is an Interface Material Needed?

Gaps in interface dueto non-planarity.

Gaps can be quitelarge.

Conduction acrossgap is poor.

Surfaces are not Planar

Thermal resistance of InterfaceMaterial is

θθθθ = (Tsink - T die)/Q

BiTS20011/05/01

Use of a Thermal Interface Material During Burn-in

Ideally, you would use no interface material No need to clean No need to replace material after each cycle.

But, Then Dont have cushioning for die. Usually must polish heat sink base. More of the thermal budget will be occupied by interface

thermal resistance →→→→ larger heat sink.

Compromise by using an interface material thatlasts many cycles, performs well under burn-inconditions but does not leave a residue.

BiTS20011/05/01

Characterizing interface materials for Burn-in Use

Desired Properties Typical available Information

Low Thermal resistance Thermal resistance at one pressure

High Mechanical Compliance (sometimes) mechanical compliance data.

Robust enough to last severalhundred + cycles

No cycling info

Leaves no residue on die thatmust be cleaned.

No residue info

Easy to use and apply Some use info

Withstands high temperatureburn-in environment with nodegradation in properties fromlower temperature

No measurement of high temperatureproperties.

BiTS20011/05/01

Materials Used in Characterization Tests

Material DescriptionA Silicone Gel material with conductive filler,

0.010 thickB Elastomeric Pad with thermally conductive

filler, 0.020 thickC Graphite foil, 0.020 thickD Composite of aligned carbon fibers in polymeric

matrix [2], 0.020 thickD1 Improved version of material D, 0.020 thick

BiTS20011/05/01

00.05

0.10.15

0.20.25

0.30.35

0.40.45

0.5

0 50 100 150 200 250 300

Test Pressure (psi)

Ther

mal

Res

ista

nce

(Cin

2/W

)Pressure Sensitivity of Thermal Perf.

Increasing Pressure

Decreasing Pressure

Cut Bar Test

Ensure Material Performs Well at pressure in burn-in

BiTS20011/05/01

Benefits of Having a Compliant Interface

Force across die surface and thermalcontact can be more uniform.

Die surface is cushionedwill not scratch

Can absorb tolerances if die height fromdevice to device is different

BiTS20011/05/01

BiTS20011/05/01

Mechanical Compliance

Many material suppliers report some mechanical compliance.

Need enough compliance at socket pressure to overcomemechanical tolerance stackups.

0

5

10

15

20

25

0 0.001 0.002 0.003 0.004 0.005 0.006 0.007

Displacement (in)

Appl

ied

Pres

sure

(psi

)

Material A

Material B

Material C

Material D

BiTS20011/05/01

Thermal Performance At Elevated Temperature

In general, you want thermalperformance reported as afunction of pressure.

Some materials may performdifferently at elevatedtemperatures, socharacterization should bedone at use temperature.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 10 20 30 40 50Pressure (psi)

Ther

mal

Res

ista

nce

(C in

2/W

)

Material A (70C)

Material A (130C)

Mat. D 70 C

Mat. D 130C

LowerTemperature

HigherTemperature(separation ofparticles).

BiTS20011/05/01

Filmy Residue left on Die

(e)

Residue Left on die can causeproblems with downstreamprocesses marking bonding thermal interface application

Residue must be cleaned, ifpresent.

Metric for characterizing residueis a visual since amount ofresidue is usually too little todetect otherwise.

Some materials leave an oily film.

BiTS20011/05/01

Flake type Residue Left on DIe

Some interface materialslost chunks of material onthe die Chunks could migrate off

die and cause problemselsewhere.

Interface materialperformance will degrade asthe material falls apart.

BiTS20011/05/01

Residue Left on Die

InterfaceMaterial

300 pressurecycles at roomtemperature

20 tempcycles,25C-150C

Bake48 hours at150°°°°C

Material A Residue Residue Residue, sticksto die.

Material B Residue Residue ResidueMaterial C No Residue Flaking Residue,

FlakingMaterial D No Residue No Residue Residue

Poor adhesionMaterial D1 No Residue No Residue No Residue

Good adhesion

BiTS20011/05/01

Material Robustness

Want interface material tolast many cycles without adegradation in performance. Cycle several hundred to

several thousand on-offpressure cycles.

Use application temperature Use application pressure

Cycling tests can be difficultor time consuming to make try to correlate other tests

methods or materialsproperties.0.00

0.020.040.060.080.100.120.140.160.18

0 200 400 600 800 1000

Cycles

Ther

mal

Res

ista

nce

(Cin

2 /W)

Sample 1, Material D1

Sample 2, Material D1

Vertical Motionon and off Die

Heat Sink

Heater

ThermocoupleHoles

Interface Material

BiTS20011/05/01

Robustness - Material Strength

Do a tensile test onmaterial pull a 0.5 wide strip to

breaking. Record load at failure

Tests had similar resultsat room temperature andelevated temperature

Results did not correlatewith robustnessbehavior.

Tensile Test

0

1

2

3

4

Material D Material B

Poun

ds Room Temp150 C

BiTS20011/05/01

Robustness - Abrasion Resistance

Cycling, particularly witha clamshell socket, ismore represented byabrasion.

Standard abrasion testsare too severe.

Tried to automate anabrasion tests using asoft, foam brush. Materials that tended to

flake or tear in cycling failedhere

0.100

Interface Material

Instron (vertical motion)

Heat Sink

Foam Brush

BiTS20011/05/01

Cost Advantages in Using an compliant interface

Use lower thermal resistance heat sinkSmaller heat - can put more sockets per boardReduce fin height - reduce distance between

boards/racksReduce heat sink aspect ratio (fin packing) leads

to a less expensive heat sink

Yield improvementsmechanical cushioning of die will reduce

breakage or damage.

BiTS20011/05/01

Summary

Using an interface material for a burn-in thermalsolution may enable lower cost heat sinks to be used.

Burn-in is a severe environment for an interfacematerial.

Conventional interface tests do not tell everything thatis needed to predict success in a high temperature,repetitive assembly environment.

Conventional tests that are of interest are Thermal resistance as a function of pressure Mechanical compliance Bake tests

BiTS20011/05/01

Summary

New characterization methods that did correlatewith burn-in suitability High temperature bake in contact with silicon die abrasion test high temperature thermal resistance

Characterization methods were used to optimize amaterial (D) for burn-in use Maximize mechanical cycling minimize residue maintain good thermal performance at elevated

temperatures

BiTS20011/05/01

burn-in & test socket workshop - testconx · professional services are needed costly-1. page 7...

Documents