Moisture migration in PQFPs (plastic quad flat packages) was investigated analytically and experimentally. Coupons made of the molding compound material were exposed to humid air for an extended time to determine its equilibrium moisture composition as a function of environmental moisture level. An IR (infrared) heating test was designed to simulate the high-temperature heat reflow process when PQFPs are soldered on computer boards. The C-SAM (C-mode Scanning Acoustic Microscopy) technique was employed to measure the delaminated areas. All packages failed after IR heating when the moisture content in PQFPs was higher than 60 percent of the equilibrium composition.

1.
Belton, D. J., Sullivan, E. A., and Molter, M. J., 1987, “Moisture Sorption and Its Effects Upon the Microstructure of Epoxy Molding Compounds,” Proceedings of the IEEE Components and Technology Conference, pp. 158–169.
2.
Bhattacharyya, B. K., and Huffman, W. A., 1988, “Moisture Absorption and Mechanical Performance of Surface Mountable Plastic Packages,” Proceedings of the IEEE Components and Technology Conference, pp. 49–58.
3.
Bird, R. B., Stewart, W. E., and Lightfoot, E. N., 1960, Transport Phenomena, John Wiley & Sons, Inc., New York, NY, pp. 494–542.
4.
Gebhart, B., 1993, Heat Conduction and Mass Diffusion, McGraw-Hill, New York, NY, pp. 184–190.
5.
Harada, M., and Tanigawa, S., 1992, “X-Ray Analysis of the Package Cracking During Reflow Soldering,” Proceedings of the IEEE Components and Technology Conference, pp. 182–189.
6.
INTEL, 1993, private communications.
7.
Jahsman
W. E.
,
Kinsman
K. R.
, and
Sundahl
R. C.
,
1989
, “
Moisture and Plastic Package Stability
,”
Materials Research Society Symposium Proceedings
, Vol.
154
, Materials Research Society, Pittsburgh, PA, pp.
131
141
.
8.
Kays, W. M., and Crawford, M. E., 1980, Convective Heat and Mass Transfer, 2nd Ed., McGraw-Hill, New York, NY, p. 15.
9.
Kinsman, K. R., 1987, “Integrated Circuit Packaging—A Materials Microcosm,” Proceedings of ASM’s 3rd Conference on Electronic Packaging: Materials Processes & Corrosion in Microelectonics, ASM, pp. 1–10.
10.
Kinsman
K. R.
,
1988
, “
The Mechanics of Molded Plastic Packages
,”
Journal of Metals
, Vol.
40
, No.
6
, pp.
23
29
.
11.
Kornblum, Y., and Glaser, J. C., 1989, “Combined Moisture and Thermal Stresses Failure Mode in a PLCC,” ASME Winter Annual Meeting Proceedings, pp. 1–6.
12.
McMaster
M. G.
, and
Soane
D. S.
,
1989
, “
Water Sorption in Epoxy Thin Films
,”
IEEE Transactions on Components, Hybrids, and Manufacturing Technology
, Vol.
12
, No.
3
, pp.
373
386
.
13.
Nishioka, T., Hagasawa, M., Igarashi, K., and Kohmoto, M., 1990, “Special Properties of Molding Compound for Surface Mounting Devices,” Proceedings of the IEEE Components and Technology Conference, pp. 625–631.
14.
Shook, R. L., 1992, “Moisture Sensitivity Characterization of Plastic Surface Mount Devices Using Scanning Acoustic Microscopy,” Proceedings of the IEEE Components and Technology Conference, pp. 157–168.
15.
Shoraka, F., Kinsman, K. R., Natarajan, B., and Gealer, C., 1986, “Package and Molding Compound Mechanics,” Proceedings of the IEEE Components and Technology Conference, pp. 294–312.
16.
Siettmann, J., and Dias, R., 1989, “Scanning Acoustic Microscopy—A New Technique for the Nondestructive Analysis of Microelectronic Packages,” IEEE Proceedings, pp. 1–7.
17.
Taylor, S. A., 1993, “The Effect of Moisture Content on Cracking and Delaminationin Microelectronic Plastic Quad Flat Packages,” M. S. thesis, Mechanical Engineering Department, University of Utah, Salt Lake City, UT.
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