A case study characterizes solder joint integrity of different BTC constructions in an accelerated lifetime test.

The electronics industry has extensively documented the influence of component construction on solder joint integrity. Materials used in the construction of a component package body result in a composite coefficient of thermal expansion (CTE) for the package that may result in the degradation of the package solder joint integrity. The industry discovered in the 2000s the construction design of ball grid array (BGA) packages had a significant influence on solder joint integrity. BGA solder balls located directly beneath and sometimes adjacent to the package internal die-to-package transition region (i.e., the die shadow region) failed first due to the CTE mismatch forces.1-3 Extensive finite element modeling, combined with use environment experiences and test data4-5 resulted in package redesign protocols that for the most part eliminated die shadow solder ball failure in BGA packages.

This paper documents an investigation of the impact of bottom-terminated component (BTC) package construction on solder joint integrity using thermal cycle testing (-55° to +125°C) in accordance with IPC-9701.

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