This paper investigates the effect of the anisotropic behavior of the die and the time- and temperature-dependent behavior of epoxy molding compound on the packaging induced stresses for a quad flat package. Finite element (FE) simulations using isotropic and anisotropic properties of the die are carried out, respectively, and the results are compared. Creep experiments were performed at different temperatures ranging from −65°C to 230°C to obtain the long-term master curves and the related shift factors for the creep compliance of the molding compound. FE models which incorporate the viscoelastic constitutive relation of the material are constructed to simulate the thermo-mechanical stresses caused by the packaging processes. The influences of both the chip anisotropy and the viscoelastic behavior of the molding compound on the packaging induced stresses are discussed.

Issue Section:
Technical Papers
Keywords:
integrated circuit packaging, moulding, polymers, internal stresses, thermal stresses, finite element analysis, creep, viscoelasticity
Topics:
Anisotropy, Molding, Packaging, Stress, Temperature, Viscoelasticity, Finite element analysis
1.
McSkimin
,
H. J.
, and
Andreatch
,
P.
,
1964
, “
Elastic Moduli of Silicon vs Hydrostatic Pressure at 25.0C and −195.8C
,”
J. Appl. Phys.
,
35
, pp.
2161
–
2165
.
2.
Nikanorov
,
S. P.
,
Burenkov
,
Yu. A.
, and
Stepanov
,
A. V.
,
1972
, “
Elastic Properties of Silicon
,”
Sov. Phys. Solid State
,
13
, pp.
2516
–
2579
.
3.
George, A., 1999, “Elastic Constants and Moduli of Diamond Cubic Si,” in Properties of Crystalline Silicon, edited by R. Hull, Inspec Publishing, London.
4.
Maissel
,
L.
,
1960
, “
Thermal Expansion of Silicon
,”
J. Appl. Phys.
,
31
, pp.
211
–
214
.
5.
Ibach
,
H.
,
1969
, “
Thermal Expansion of Silicon and Zinc Oxide
,”
Phys. Status Solidi
,
31
, pp.
625
–
634
.
6.
Shah
,
J. S.
, and
Straumanis
,
M. E.
,
1972
, “
Thermal Expansion Behavior of Silicon at Low Temperatures
,”
Solid State Commun.
,
10
, pp.
159
–
162
.
7.
Nakamura
,
S.
,
Miyano
,
Y.
,
Sugimori
,
S.
, and
Kaneda
,
A.
,
1988
, “
Thermoviscoelastic Analysis of Residual Stresses in a Thermosetting Resin/Metal Laminated Beam Caused by Cooling
,”
JSME Int. J., Ser. I
,
31
, pp.
556
–
559
.
8.
Yeung, T. S., and Yuen, M. M. F., 1996, “Viscoelastic Analysis of IC Package Warpage, Sensing, Modeling and Simulation in Emerging Electronic Packaging,” ASME, EEP-Vol. 17, pp. 101–107.
9.
Yi
,
S.
, and
Sze
,
K. Y.
,
1998
, “
Cooling Rate Effect on Post Cure Stresses in Molded Plastic IC Packages
,”
ASME J. Electron. Packag.
,
120
, pp.
385
–
390
.
10.
Boomen, R. v.d., and Seegers, M. C., 1990, “Leadframe Materials,” Philips internal report.
11.
Kruis, R. F., 1990, “Numerical Analyses of Thermal Stress Related Failures in IC Packages,” Philips internal report.
12.
Yang
,
D. G.
,
Ernst
,
L. J.
,
Bisschop
,
J.
,
Janssen
,
J.
,
Kuper
,
F.
,
Liang
,
Z. N.
,
Schravendeel
,
R.
, and
Zhang
,
G. Q.
,
2000
, “
Vertical Die Crack Stresses of Flip Chip Induced in Major Package Assembly Processes
,”
Microelectron. Reliab.
,
40
, pp.
1533
–
1538
.
13.
Zhang, G. Q., and Stehouwer, H. P., 2000, “Simulation-base Optimization in Virtual Thermo-mechanical Prototyping of Electronic Packages,” in Benefiting from Thermal and Mechanical Simulation in Micro-electronics, edited by G. Q. Zhang and L. J. Ernst, Kluwer Academic Publishers, Dordrecht, The Netherlands, pp. 151–164.
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 by ASME
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