Residual stresses during cool down process after curing are evaluated on the basis of thermoviscoelastic finite element analyses with material properties dependent on both time and temperature. Temperature distributions in packages are predicted by solving the heat conduction equations. The effects of cool-down history on thermomechanical responses of a lead-on-chip (LOC), thin small outline package (TSOP) are investigated. Three linear cool down temperature histories are considered. Numerical results show that residual stresses in a LOC TSOP are significantly influenced by the manufacturing temperature history. Residual stresses in plastic packages are strongly time-temperature dependent due to the thermoviscoelastic behavior of molding compounds. Substantial residual stresses arise when a LOC TSOP has cooled to room temperature and rapid cool down permits small viscoelastic effects.

1.
Amagai
M.
,
Seno
H.
, and
Ebe
K.
,
1995
, “
Cracking Failures in Lead-On-Chip Packages Induced by Chip Backside Contamination
,”
IEEE Trans. on Components, and Manufacturing Technology—Part B
, Vol.
18
, No.
1
, pp.
119
126
.
2.
Hagen, D., 1992, “Lead-On-Chip TSOP Assembly Process for Fast SRAM With Peripherally Located Bond Ads,” Proc. IEEE Int. Electron. Manufact. Technol. Symp., IEEE, Piscataway, NJ, pp. 39–47.
3.
Miura
H.
,
Kitano
M.
,
Nashimura
A.
, and
Kawai
S.
,
1993
, “
Thermal Stress Measurement in Silicon Chips Encapsulated in IC Plastic Packages Under Temperature Cycling
,”
ASME JOURNAL OF ELECTRONIC PACKAGING
, Vol.
115
, pp.
9
15
.
4.
Lin
K. Y.
, and
Yi
S.
,
1991
, “
Analysis of Interlaminar Stresses in Viscoelastic Composites
,”
International Journal of Solids and Structures
, Vol.
27
, No.
7
, pp.
929
945
.
5.
Pecht
M.
,
Wu
X.
,
Paik
K. W.
, and
Bhandarkar
S. N.
,
1995
, “
To Cut or Not to Cut: A Thermomechanical Stress Analysis of Polyimide Thin-Film on Ceramic Structures
,”
IEEE Trans. on Components, and Manufacturing Technology—Part B
, Vol.
18
, No.
1
, pp.
150
153
.
6.
Hilton, H. H., and Dong, S. B., 1964, “An Analogy for Anisotropic Nonhomogeneous, Linear Viscoelasticity Including Thermal Stresses,” Proc. of 8th Midwestern Mechanics Conference, ASME, New York, pp. 58–73.
7.
Taylor
R. L.
,
Pister
K. S.
, and
Goudreau
G. L.
,
1970
, “
Thermomechanical Analysis of Viscoelastic Solids
,”
International Journal for Numerical Methods in Engineering
, Vol.
2
, pp.
45
59
.
8.
Yi
S.
,
1993
, “
Thermoviscoelastic Analysis of Delamination Onset and Free Edge Response in Epoxy Matrix Composite Laminates
,”
AIAA Journal
, Vol.
31
, No.
12
, pp.
2320
2328
.
9.
Yi
S.
,
Hilton
H. H.
, and
Ahmad
M. F.
,
1998
, “
Cure Cycle Simulations of Composites with Temperature and Cure Dependent Anisotropic Viscoelastic Properties and Stochastic Delaminations
,”
Mechanics of Composite Materials Structures
, Vol.
5
, No.
1
, pp.
81
101
.
10.
Yi
S.
,
Goh
J. S.
, and
Yang
J. C.
,
1997
, “
Residual Stresses in Plastic IC Packages During Surface Mounting Process Preceded by Moisture Soaking Test
,”
IEEE Transactions on Components, Packaging, and Manufacturing Technology—Part B
, Vol.
20
, No.
3
, pp.
247
255
.
This content is only available via PDF.
You do not currently have access to this content.