The failure of electrical devices associated with solder joints has become one of the most critical reliability issues for surface-mounted devices. Solder joint reliability performance has been found to be highly dependent on the solder joint configuration, which, in turn, is governed by bond pad size, alloy material, and leadframe structure, as well as solder reflow characteristics. To investigate tombstone effects causing solder joint failure during leadless component reflow process, this work has focused on (1) developing a numerical model for the simulations of the solder joint formation during the reflow process, and (2) determining possibility that a tombstone effect for the leadless component may occur by analyzing the force and torque in the problem. Using this methodology, the tombstone effect associated with different pad geometry configurations and solder paste amount has been analyzed through the application of the public domain software tool Surface Evolver. Simulations show that the tombstoning is very sensitive to pad/component geometry design, solder surface tension, solder paste volume, wetting area, and wetting angle. This model simulation can be used to determine optimal solder paste volume, pad geometry configurations, and solder material for avoiding tombstone effects.

Issue Section:
Special Section Technical Papers
Topics:
Simulation, Solder joints, Solders, Geometry, Engineering simulation, Failure, Reliability, Wetting, Alloys, Computer simulation, Computer software, Design, Reflow soldering, Surface tension, Torque
1.
Brakke, K. A., 1995, Surface Evolver Manual, Version 1.99, The Geometry Center, 1300 S. Second St., Minneapolis, MN 55454.
2.
Charles
H. K.
, and
Clatterbaugh
G. V.
,
1990
, “
Solder-Joint Reliability—Design Implications From Finite Element Modeling and Experimental Testing
,”
ASME JOURNAL OF ELECTRONIC PACKAGING
, Vol.
112
, No.
2
, pp.
135
–
146
.
3.
Engelmeir
W.
,
1993
, “
Generic Reliability Figures of Merit Design Tools for Surface Mount Solder Attachments
,”
IEEE Transactions on Components, Hybirds and Manufacturing Technology
, Vol.
16
, No.
1
, pp.
103
–
112
.
4.
Heinrich, S. M., 1994, “Prediction of Solder Joint Geometry,” chap. 5 in The Mechanics of Solder Alloy—Interconnects, Van Nostrand Rheinhold, New York, pp. 158–198.
5.
Ikegami, K., 1992, “Some Topics of Mechanical Problems in Electronic Packaging,” Advances in Electronic Packaging—Proceedings of the 1992 Joint ASME/JSME Conference on Electronic Packaging, ASME, NY, pp. 567–573.
6.
Klein-Wassink, R. J., 1989, Soldering in Electronics, Electrochemical Publications Limited, Scotland.
7.
Lau, J. H., 1991, Solder Joint Reliability: Theory and Applications, Van Nostrand Rheinhold, New York, NY.
8.
Moon
K. W.
,
Boettinger
W. J.
,
Williams
M. E.
,
Josell
D.
,
Murray
B. T.
,
Carter
W. C.
, and
Handwerker
C. A.
,
1996
, “
Dynamic Aspects of Wetting Balance Tests
,”
ASME JOURNAL OF ELECTRONIC PACKAGING
, Vol.
118
, No.
3
, pp.
174
–
183
.
9.
Whalley
D. C.
, and
Conway
P. P.
,
1996
, “
Simulation and Interpretation of Wetting Balance Tests Using the Surface Evolver
,”
ASME JOURNAL OF ELECTRONIC PACKAGING
, Vol.
118
, No.
3
, pp.
134
–
141
.
10.
Wu, X., Hu, K., Dou, X., Mui, G., Yeh, C., and Wyatt, K., 1997, “Solder Joint Formation Simulation and Reliability Prediction,” Design and Reliability of Solder and Solder Interconnections, Proceedings of Symposium held during the TMS Annual Meeting at Orlando, ASME, NY.
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