The reduction of the warpage of LSI package is a critical issue to ensure good solder joint connection in surface mount. In this study, different combinations of finite element and calculating methods were used to investigate the best method for predicting the thin small outline packages (TSOP) warpage. The results indicate that viscoelastic-GK calculation with relaxation of shear modulus and of bulk modulus using the multilayer shell element is the most appropriate method for predicting the warpage. All calculations confirm that a compound thickness ratio of 1.2 results in minimal warpage for a large chip TSOP. In this case, the warpage is reduced to near zero and the compound properties have little influence on warpage. However, for a small chip TSOP, a compound thickness ratio of 2.0–2.9 reduces the warpage. The warpage of small chip TSOP shows a severe saddle shape. The ratio and the magnitude of warpage depend on the compound properties. Also, the elastic method may result in a false simulation.

Issue Section:
Technical Papers
Keywords:
surface mount technology, integrated circuit packaging, plastic packaging, viscoelasticity, elastic moduli, shear modulus, elastic deformation, finite element analysis
Topics:
Warping, Surface mount packaging, Shells
1.
Lee, C. K., and Yan, J. C., 1998, “Warpage in Plastic IC Packages,” 48th ECTC.
2.
Miyake, K., and Saitou, K., 1997, “Analysis of Warpage of Surface Mount Devices,” JSME The 10th Computer Mechanics Conf., pp. 41–42.
3.
Sang, W. P., Hyung, G. B., Suck, J. Y., Kwang, Y. B., and Kil, S. R., 1998, “Warpage Simulation for TSOP (LOC)-Package,” SEMICON Korea.
4.
Miyake, K., Yoshida, T., Hyung, G. B., and Sang, W. P., 1999, “Visco-elastic Warpage Analysis of Surface Mount Package,” ASME Advances in Electronic Packaging, EEP-Vol. 26-1, pp. 1041–1046.
5.
Miyake, K., Yoshida, T., Hyung, G. B., and Sang, W. P., 1999, “Visco-elastic Warpage Analysis of TSOP” 4th ICRMS99 Shanghai, pp. 353–358.
6.
Brian, D. H., 1997, “Effects of Temperature and Moisture upon the Mechanical Behavior of an Epoxy Molding Compound,” ASME Advances in Electronic Packaging, EEP Vol. 19-1.
7.
Lance
,
R. W.
,
Shane
,
T. S.
, and
Yves
,
H. B.
,
1997
, “
An Experimental-Numerical Technique for Evaluating the Bulk and Shear Dynamic Moduli of Viscoelastic Materials
,”
J. Acoust. Soc. Am.
,
102
, No.
6
, pp.
3549
–
3555
.
8.
Nakamura, S., Hasebe A., and Serizawa, K., 1995, “Thermo-viscoelastic Analysis of Warp Deformation for Resin and Metal Laminated Substrate,” 6th MES95.
9.
Sasaki
,
K.
,
Saitou
,
N.
,
Amagi
,
S.
, and
Haraguchi
,
Y.
,
1998
, “
Numerical Analysis of Residual Stress in Resin-Molded Poducts
,”
Trans. Jpn. Soc. Mech. Eng., Ser. A
64
, No.
622
, pp.
1660
–
1666
.
10.
MARC Manual-A, 1998, pp. 272–276.
11.
Miki
,
Y.
,
Onishi
,
H.
, and
Asano
,
T.
,
1986
, “
Analysis of Contact Process of Adhesive Tape
,”
Nitto Technical Report
,
2
, No.
24
, pp.
16
–
27
.
Copyright © 2001
 by ASME
You do not currently have access to this content.