Wire sweep has been recognized as one of the major defects in encapsulation of electronic components by transfer molding. The phenomenon is very complicated as it is sensitive to a large number of parameters. In this experimental work, where a 160L QFP package used as the test vehicle, the detailed time-dependent wire displacement is measured for the following two different flow initial conditions: (i) the wire is immersed in the liquid and is displaced due to the acceleration of the flow from rest to the steady-state velocity, and (ii) the wire is surrounded by the ambient air and is displaced first due to the passage of the liquid front and then due to the hydrodynamic load. Significant differences have been observed between the two cases, with important implications for analytical and numerical studies of wire sweep.

Issue Section:
Technical Briefs
Topics:
Transfer molding, Wire, Flow (Dynamics), Displacement, Electronic components, Steady state, Stress, Vehicles
1.
Chai, H., and Zohar, Y., 1997, “Wire Sweep due to transfer molding in a 160L QFP package Under Steady-State Conditions,” ASME JOURNAL OF ELECTRONIC PACKAGING, in press.
2.
Chen, X. H., Yuen, M. M. F., and Tong, P., 1996, “Flow Modeling of Wire Sweep in Transfer Molding,” Proceedings, ASME Winter Annual Meeting, EEP-Vol. 17, 55.
3.
Han
S.
, and
Wang
K. K.
,
1995
, “
A Study on Wire Sweep in Encapsulation of Semiconductor Chips Using Simulated Experiments
,”
ASME JOURNAL OF ELECTRONIC PACKAGING
, Vol.
117
, p.
178
178
.
4.
Hunter
W. L.
,
1987
, “
Association of Bonding-Wire Displacement With Gas Bubbles in Plastic-Encapsulated Integrated Circuits
,”
IEEE Trans. Comp., Hybrids, Manuf. Tech.
,
CHMT-10
, p.
327
327
.
5.
Manzione, L. T., 1983, “Packaging of Microelectronic Devices,” SPE 41st ANTEC, p. 77.
6.
Nguyen
L. T.
,
1988
, “
Wirebond Behavior During Molding Operations of Electronic Packages
,”
Polym. Eng. Sci.
, Vol.
28
, p.
926
926
.
7.
Nguyen, L. T., Danker, A., Santhiran, N., and Shervin, C. R., 1992, “Flow Modeling of Wire Sweep During Molding of Integrated Circuits,” Proceedings, ASME Winter Annual Meeting, Vol. 27.
8.
Nguyen, L. T., and Lim, F. J., 1990, “Wire Sweep During Molding of Integrated Circuits,” Proceedings, 40th Electron. Comp. and Tech. Conf., p. 777.
9.
Reusch, R. K., 1987, “Wire Sweep in Small Outline Package,” Semiconductor Int., p. 139.
10.
Tay
A. A. O.
,
Yeo
K. S.
,
Wu
J. H.
, and
Lim
T. B.
,
1995
, “
Wirebond Deformation During Molding of IC Packages
,”
ASME JOURNAL OF ELECTRONIC PACKAGING
, Vol.
117
, p.
14
14
.
11.
Suhir
E.
, and
Manzione
L. T.
,
1991
, “
Predicted Stresses in Wirebonds of Plastic Packages During Transfer Molding
,”
ASME JOURNAL OF ELECTRONIC PACKAGING
, Vol.
113
, p.
16
16
.
12.
Wu, J. H., Tay, A. A. O., Yeo, K. S., and Lim, T. B., 1996, “Three Dimensional Modeling of Wire Sweep Incorporating Resin Cure,” Proceedings, 46th Electron. Comp. & Tech. Conf., p. 1047.
This content is only available via PDF.
Copyright © 1999
 by The American Society of Mechanical Engineers
You do not currently have access to this content.