Electronic Packaging/CAE Labs National Tsing Hua University. Electronic Packaging/CAE Labs National Tsing Hua University. Electronic Packaging/CAE Labs

Electronic Packaging/CAE Labs

National Tsing Hua University

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. Electronic Packaging/CAE Labs


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Parametric Study of Flip Chip Analysis

Electronic Packaging Lab. of NTHUElectronic Packaging Lab. of NTHU國立清華大學動機系電子構裝實驗室



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S u b s t r a t e

E u t e c t i c S o l d e r B a l l

U n d e r f i l l

D i e

F l i p C h i p C r o s s - S e c t i o n

15 30 45 60 75

-40oC

125oC

Accelerated Thermal Cycling

Typical Conditions:• 1hr/cycle• Long duration time; -40oC to 125oC, 1000 cycles•Implicit Transient problem•Material nonlinear/Creep/Temperature dependent, Eutectic Solder (63Sn/37Pb) Tm=183oC FR4 Tg is around 130 oC

20 oC

100 oC

0.0100.0080.0060.0040.0020.0000.0

10.0

20.0

30.0

Strain

Str

ess

(Mp

a)

(273 + 20oC) = 0.6425(273 + 183oC)

Flip Chip (6mm x 6mm) 1/8 Finite Element ModelFlip Chip (6mm x 6mm) 1/8 Finite Element Model(26,262 Solid-3D Elements)(26,262 Solid-3D Elements)




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Parametric study results for underfill fillet height

0.005 0.1 0.2 0.3 0.4

2

4

6

8

10

12

underfill fillet height (mm)

Max

. Von

Mis

es s

trai

n (E

-03)

underfill

silicon die

solder ball




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Parametric study results for silicon die thickness

2

4

6

8

10

12

Max

. Von

Mis

es s

trai

n (E

-03)

underfill

silicon die

silicon die thickness (mm)

0.125 0.35 0.575 0.8 1.025 1.25

solder ball




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Parametric study results for PWB thickness

2

4

6

8

10

12

Max

. Von

Mis

es s

trai

n (E

-03)

underfill

silicon die

0.125 0.35 0.575 0.8 1.025 1.25

PWB thickness (mm)

solder ball




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Parametric study results for underfill CTE

2

4

6

8

10

12

Max

. Von

Mis

es s

trai

n (E

-03)

underfill

silicon die

22 24 26 28 30 32

underfill CTE (ppm)

solder ball




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Paametric study results for Young'smodulus of PWB (in-plane direction)

2

4

6

8

10

12M

ax. V

on M

ises

str

ain

(E-0

3)

underfill

silicon die

11.0 12.4 13.8 15.2 16.6

Young's modulus of PWB (in-plane direction, GPa)

solder ball




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Parametric study results for Young's modulus of PWB (out-of-plnae direction)

2

4

6

8

10

12

Max

. Von

Mis

es s

trai

n (E

-03)

underfill

silicon die

2.4 5.5 8.6 11.7 14.8 17.9

Young's modulus of PWB (out-of-plane direction, GPa)

solder ball




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Parametric study results for PWB CTE (in-plane direction)

2

4

6

8

10

12

Max

. Von

Mis

es s

trai

n (E

-03)

underfill

silicon die

PWB CTE (in-plane direction, ppm)

18.0 19.8 21.6 23.4 25.2 27.0

solder ball




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0

2

4

6

8

10

12

14

16

18

20

Bare Die withoutUnderfill

Flip Chip with Underfill Micro-BGA withoutUnderfill

Fa

ilure

-Fre

e L

ife

(Y

ea

rs)

Reliability of Reliability of BGA vs. Flip ChipBGA vs. Flip ChipSource: Electronic Packaging and Production, June, 1997


Documents

Electronic Packaging/CAE Labs National Tsing Hua University. Electronic Packaging/CAE Labs National Tsing Hua University. Electronic Packaging/CAE Labs