PREDICTIVE AND ANALYTICAL METHODS FOR RAPIDLY …

S. Rahman, K. K. Choi, T. Zhang, and J. TangCenter for Computer-Aided Design (CCAD)

The University of IowaIowa City, IA 52245

PREDICTIVE AND ANALYTICAL METHODSFOR RAPIDLY ASSESSING THE RELIABILITY OF COMMERCIAL ELECTRONIC PACKAGING FOR

MILITARY/INDUSTRIAL ENVIRONMENTS

September 17, 2002

OUTLINE

• Objective of this Project

• A Simulation-based Methodology

• Experimental Validation Effort

♦ In-plane Displacement of ASAT 144 Package

♦ Out-of-plane Displacement of CSP Assembly

• Accomplishments in 10/01-9/02

• Future Efforts

OBJECTIVE

• Develop a physics-of-failure- and simulation-based prediction methodology which would allow for rapid assessment of the reliability of advanced packaging technologies

Project started in January 1999

SIMULATION-BASED METHODOLOGY

• Chip Scale Package

PCB

solder ballRigid Carrier

Die Attach

Die Chip

Molding Compound

Part: ASAT 144b1

b2

h5

h1

h2

h3

h4

b3

b4

0 2500 5000 7500 10000 12500

Time, s

-100

0

100

200

Tem

pera

ture

, C

125 C

-55 C

! Input

— Geometry

— Material Properties

— Load (Temperature)

! Stress Analysis

— Nonlinear FEA

! Output

— Deformation, Stress, Strain, etc.

— Fatigue Life

Full-Scale FEA of CSP iscomputationally prohibitive


• A Three-Step Process for Durability Analysis

GLOBALDEFORMATION

ANALYSIS

• Simplified SolderJoint Model

• Equivalent Model• Relative Displ.

Time History

FATIGUELIFE

ANALYSIS

• Critical PlaneMethod

• Assessment ofDurability andReliability

CRITICALSOLDER JOINT

ANALYSIS

• Detailed Model ofActual Solder Joint

• Displ. Input fromGlobal Analysis

• Calculation of Stresses & Strains

PATRANABAQUS

PATRANABAQUS

DRAW[In-house

Developed]


• Global Deformation Analysis

• Equivalent brick/diamond model for solder joint

• Coarse mesh for solder joint; detailed mesh for other parts

• Calculate displacement field of critical solder joint

Critical Joint

Center11ú1mm=11mm

11ú

1mm

=11

mm


• Critical Solder Joint Analysis

• High-fidelity mesh for critical solder joint

• Apply displacement field from global analysis

• Calculate stresses/strains at critical solder joint

Von Mises Stress


• Fatigue Life Analysis

EXPERIMENTAL VALIDATION

• Experimental Work at RC and RSC ♦ ASAT 144 Package (with solder balls removed)

− In-plane displacement measurements of package by HASMAP (this year)

− Out-of-plane displacement measurements of Package by Shadow Moiré Testing

♦ PCB− In-plane displacement measurements of

package by HASMAP (CTE calculation)

♦ CSP Assembly (package & board soldered together)− In-plane relative displacement measurements

of the farthest solder joint by HASMAP− Out-of-plane relative displacement

measurements of various solder joints by HASMAP (this year)

IN-PLANE DISP. OF PACKAGE

• ASAT 144 Package

RT to 125 C


• ASAT 144 Package

RT to 35 C RT to 90 C


• Raw Pixel Data

Raw pixel data were translated to physical displacement measurements

x y delta_x delta_y x y delta_x delta_y x y delta_x delta_y88 98 -0.13786 0.121734 273 206 0.010189 0.10115 88 350 -0.21193 0.32445125 98 -0.27428 -0.61355 310 206 0.07611 0.101602 125 350 -0.18965 0.304725162 98 -0.2346 -0.62918 347 206 0.124217 0.074594 162 350 -0.15353 0.265504199 98 -0.02048 0.022414 384 206 0.189058 0.096479 199 350 -0.09229 0.260668236 98 -0.04809 -0.05523 415 206 0.21611 0.115883 236 350 -0.05072 0.263097273 98 -0.0145 -0.04729 88 242 -0.26257 0.187415 273 350 -0.01576 0.27669310 98 0.058112 -0.00667 125 242 -0.15636 0.193094 310 350 0.028877 0.291304347 98 0.133234 -0.06498 162 242 -0.05862 0.175329 347 350 0.121295 0.307573384 98 0.096211 0.009571 199 242 -0.03387 0.151872 384 350 0.198803 0.367774415 98 0.086348 0.042332 236 242 0.101021 0.135083 415 350 0.26304 0.37762688 134 -0.18712 0.035443 273 242 -0.02331 0.112756 88 386 -0.23229 0.355993125 134 -0.2701 -0.26892 310 242 0.05745 0.10075 125 386 -0.19358 0.361803162 134 -0.23543 -0.22714 347 242 0.110629 0.111892 162 386 -0.1675 0.370031199 134 -0.02835 0.040098 384 242 0.16041 0.109352 199 386 -0.11052 0.322644236 134 -0.01178 0.018335 415 242 0.26208 0.111024 236 386 -0.00717 0.267349273 134 0.01881 0.011231 88 278 -0.29982 0.255321 273 386 0.04268 0.269389310 134 0.084681 0.043846 125 278 -0.17644 0.236019 310 386 0.055529 0.283541347 134 0.116136 0.026604 162 278 -0.09549 0.216949 347 386 0.13213 0.388296384 134 0.152085 0.010879 199 278 -0.06602 0.18476 384 386 0.20562 0.400472415 134 0.202 0.003876 236 278 -0.03179 0.181868 415 386 0.241289 0.41002388 170 -0.20671 0.05836 273 278 -0.02357 0.161402 88 418 -0.18568 0.377867125 170 -0.11331 0.099875 310 278 0.031078 0.159814 125 418 -0.2024 0.410214162 170 -0.0767 0.113407 347 278 0.08261 0.17196 162 418 -0.1834 0.431789199 170 -0.04941 0.098486 384 278 0.112231 0.180302 199 418 -0.13467 0.420349236 170 0.025103 0.116619 415 278 0.256826 0.221859 236 418 -0.0291 0.3546273 170 0.06371 0.104746 88 314 -0.21632 0.274732 273 418 0.028947 0.337196310 170 0.08126 0.075677 125 314 -0.1568 0.272755 310 418 0.075552 0.310951347 170 0.086034 0.068257 162 314 -0.1096 0.233214 347 418 0.117022 0.425772384 170 0.150036 0.084814 199 314 -0.09832 0.23395 384 418 0.205728 0.444902415 170 0.186246 0.120773 236 314 -0.0567 0.231043 415 418 0.269267 0.47175688 206 -0.17878 0.112348 273 314 -0.03038 0.229516125 206 -0.12601 0.140178 310 314 0.069124 0.221119162 206 -0.07762 0.117677 347 314 0.108929 0.212773199 206 -0.03229 0.12783 384 314 0.143772 0.224707236 206 0.011601 0.101557 415 314 0.28414 0.292375

RT to 125 C


• Raw Experimental Data

RT to 125 C-6.5

0.0

6.5

x, mm-6.5

0.0y, mm

-9

-6

-3

0

3

6

9In

-Pla

ne (

x) D

ispl

acem

ent,

µm min: -7.62 µm

max: 8.17 µm

6.5


• Fitted Experimental Data (Full)

RT to 125 C

-6.5

0.0

6.5

x, mm-6.5

0.0y, mm

-9

-6

-3

0

3

6

9In

-Pla

ne (

x) D

ispl

acem

ent,

µm Fitted Plane (Full)

max: 7.6 µm

6.5


• Fitted Experimental Data (Quarter)

RT to 125 C0.00

3.25

6.50

x, mm0.00

3.25y, mm

0

1

2

3

4

5

6

7

8

9

In-P

lane

(x)

Dis

plac

emen

t, µ

m Fitted Plane (Quarter)

max: 7.6 µm

6.50


• Results from FEM (ABAQUS) - Quarter Model

RT to 125 C0.00

3.25

6.50

x, mm0.00

3.25y, mm

0

1

2

3

4

5

6

7

8

9

In-P

lane

(x)

Dis

plac

emen

t, µ

m FEM (ABAQUS)

max: 8.11 µm

6.50


• Comparison of Results

ExperimentFEM (ABAQUS)

0.00

3.25

6.50

x, mm0.00

3.25y, mm

0

1

2

3

4

5

6

7

8

9

In-P

lane

(x)

Dis

plac

emen

t, µ

m Fitted Plane (Quarter)

max: 7.6 µm

6.50

0.00

3.25

6.50

x, mm0.00

3.25y, mm

0

1

2

3

4

5

6

7

8

9

In-P

lane

(x)

Dis

plac

emen

t, µ

m FEM (ABAQUS)

max: 8.11 µm

6.50

OUT-OF-PLANE DISP. OF ASSEMBLY

• CSP Assembly - Motivation

0 2500 5000 7500 10000 12500

Time, s

-100

0

100

200

Tem

pera

ture

, C

125 C

-55 C

Step 1 (T = 125 C) Step 3 (T = -55 C)

From Sep 2001 presentation

0 2500 5000 7500 10000 12500

Time, s

-8E-06

-4E-06

0

4E-06

8E-06

Rel

ativ

e D

ispl

acem

ent,

ui(t

), m

u2(t)

u3(t)

u1(t)


• Past FEM (ABAQUS) Prediction

FEM predicted out-of-plane displacement to be larger than in-plane displacement - Need to be verified with experimental data

From Sep 2001 presentation


• Relative Disp. (ASAT 144 Package & FR4 PCB)

u3,top

HASMAP Analysisu3,bot

Input: RT to 125COutput: ∆u3 = (u3,top - u3,bot)


• Identification of Solder Joints

x

y

middle of edge corner

center


• Applied Temperature History

Time (s)t1 t2

Temperature (C)

35 C

125 C Step 2

Step 1

Hold Time = t2− t1


• Relative Out-of-plane displacements by FEM

t1, t2 (sec)

Middle ofEdge(µm)

Corner(µm)

60, 1060 (hold time = 1000 sec) 2.56 6.72700, 1700 (hold time = 1000 sec) 2.56 6.761400, 2400 (hold time = 1000 sec) 2.57 6.79

Middle of edge

Corner


• HASMAP Measurements at RSC

Middle of edge

RightCorner

LeftCorner

Corner(µm)

Experiment(a)

Middleof Edge

(µm)

LeftCorner

(µm)

RightCorner

(µm)Avg.(µm)

HASMAPMeasurement 1

6 9.3 8 8.65

HASMAPMeasurement 2

5.6 7.6 6.7 7.15

(a) Average of two sets of readings (01/02 – 04/02)


• Comparison with HASMAP Results

01

23

45

x, mm

01

23

45

6

y, mm

-6

-3

0

3

6

9

Rel

ativ

e O

ut-o

f-pl

ane

(z)

disp

., µ

m

7.15 (Test)

Center

min: -4.41 µmmax: 6.72 µm

5.6 (Test)

Middleof Edge

Corner

t1= 60 s

t2 = 1060 s

Middle of edgeCorner


• Recent (8/02) Shadow Moiré Testing at RSC

21 C (1.5 Fringes) 79 C (1.75 Fringes)

125 C (2 Fringes)


• New (8/02) HASMAP Results at RSC

Significant variability in the data - need to perform fatigue life sensitivity analysis

Corner(µm)

Experiment(a)

Middleof Edge

(µm)

LeftCorner

(µm)

RightCorner

(µm)Avg.(µm)

HASMAPMeasurement 1

6 9.3 8 8.65

HASMAPMeasurement 2

5.6 7.6 6.7 7.15

HASMAPMeasurement 3

8.3 9.9 11.8 10.85

ACCOMPLISHMENTS IN 10/01 - 9/02

• Experimental Validation

♦ In-plane displacements in package

♦ Out-of-plane displacements in CSP Assembly

• Technical Report

♦ In progress

• Benchmark of ABAQUS Creep Law (discussed on January 8 meeting)

• Informal meetings at UI/RSC

♦ January 8, 2002 (RC)

♦ April 16, 2002 (UI)

♦ August 27, 2002 (UI)

FUTURE EFFORTS

• Improved correlation process for validating out-of-plane displacement

♦ Bring the part/board assembly up to 125 C for 2 hours. Take the first set of measurements

♦ Ramp down to 75 C. Take a second set of measurements

♦ Ramp down to room temperature. Take a third set of measurements

♦ Hold the part at room temperature for 2 hours. Take a fourth set of measurements

The RC/RSC/UI teams will further discuss this new measurement process during working meeting today

FUTURE EFFORTS

• Sensitivity analysis of fatigue life with respect to solder ball displacement

January 2003 is the target date for completing sensitivity analysis, remaining correlation on ASAT 144, and internal technical report

• Crack initiation vs. propagation lives

• Assess feasibility of both the model and the experimental measurement techniques

• Consider evaluating 2-3 different package types

♦ SuperBGA from Amkor/Anam

♦ EasyBGA from Intel

Documents

PREDICTIVE AND ANALYTICAL METHODS FOR RAPIDLY …