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Surface Mount Technology (SMT) Substrate Material Requirements - A Brief Review

Published online by Cambridge University Press:  21 February 2011

A. Mahammad Ibrahim
A. Mahammad Ibrahim*
Affiliation:
Martin Marietta Laboratories, 1450 South Rolling Road, Baltimore, Maryland 21227
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Abstract

The state of the art for the printed circuit (pc) industry is the Surface Mount Technology (SMT) using leadless ceramic chip carriers (LCCCs). The SMT technique is used to design, fabricate, and assemble affordable high-speed, high-density electronic modules with reduced size and weight. However, to take full advantage of the SMT, new high-performance printed circuit board (PCB) substrate materials must be developed, especially if the goal is to satisfy the high reliability required in military applications. The most critical requirement is matching the in-plane coefficient of thermal expansion (CTE) with the SMT-PCB's and the chip carriers (LCCCs) to reduce the solderjoint stresses during thermal cycling. Solder-joint reliability can be improved significantly by tailoring the in-plane CTE to approximately 6–7 ppm/°C (of the alumina chip carrier) using Kevlar and/or quartz fabric-reinforced polymer composites, instead of conventional glass composites. Less attention has been focussed on other important requirements, e.g., out-of-plane (Z-axis) expansion, glass transition temperature (Tg), dielectric constant, and resin microcracking, which also play important roles in the overall performance of the substrate materials. For example, high Z-expansion puts additional strain on the plated through holes (PTH), thereby affecting PTR reliability. A low Tg significantly increases the amount of thermal stress imposed during thermal cycling on solder joints and PTH, and leads to failures. This paper contains a brief review of the requirements of a SMT-PCB substrate material, including such critical parameters as: in-plane CTE, out-of-plane CTE, Tg, dielectric constant, fiber-to-resin ratio, and resin microcracking, and their effects on solder joint reliability, PTH reliability, dimensional stability, and electrical performance.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 108 , 1987 , 159
Copyright
Copyright © Materials Research Society 1988

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References

REFERENCES

1.Love, G.F., IPC Technical Review, pp. 12–19 (1981).Google Scholar
2.Shapery, R.A., J. Composite Mater. 2, 380 (1968).Google Scholar
3.Halpin, J.C. and Pagano, N.J., AFML TR68-(395).Google Scholar
4.Ashton, J.E., Halpin, J.C., Petit, P.H., Primer on Composite Materials: Analysis (Technomic Publishing Co., Stanford, Conn., 1969), pp. 88–91.Google Scholar
5.Sanjana, Z.N., Valentich, J., and Marchetti, J.R., IPC-TP-488, 1983.Google Scholar
6.Lake, J.K. and Wild, R.N., Natl. SAMPE Symp. Exhib. 28, 1406 (1983).Google Scholar
7.Ibrahim, A.M., Green, K.A., Djordjevic, B.B., and Venables, J.D., Internatl. SAMPE Symp. 32, 1238 (1987).Google Scholar
8.Ibrahim, A.M., presented at IPC Fall Meeting, San Diego, CA, 1986.Google Scholar
9.Lee, S., IPC-TP-503, 1984.Google Scholar
10.Ibrahim, A.M. and Seferis, J.C., in Interrelations Between Processing, Structure and Properties of Polymeric Materials, edited by Seferis, J.C. and Theocaris, P.S. (Elsevier Science Publishers, Amsterdam, 1984), pp. 325–341.Google Scholar
11.Ibrahim, A.M. and Seferis, J.C., Natl. SAMPE Symp. Exhib. 28, 581 (1983).Google Scholar
12.Ibrahim, A.M. and Seferis, J.C., Polymer Composites 6, 47 (1985).Google Scholar
13.Ibrahim, A.M., presented at 9th International Thermal Expansion Symp., Pittsburgh, PA, 1986.Google Scholar
14.Lee, H. and Neville, K., Handbook of Epoxy Resins (McGraw Hill, New York, 1967), pp. 14–36.Google Scholar
15.Butler, J.M., Chartoff, R.P., and Kinzig, B.J., Natl. SAMPE Tech. Conf. 15, 660 (1983).Google Scholar
16.Ibrahim, A.M., Shah, T.K., Matienzo, L.J., and Venables, J.D., Internatl. SAMPE Symp. Exhib. 31, 669 (1986).Google Scholar