BGA and CGA solder attachments: results of low-acceleration reliability tests and analysis

Highly accelerated tests, while capable of producing in short test durations, can cause significant damage and failure as a result of damage mechanisms and/or material behavior not present in the actual use. This is particularly true for surface mount solder attachments. The results of low-acceleration reliability tests for the solder attachments of ball grid arrays (BGAs) and column grid arrays (CGAs) are reported in this paper. The tests were designed to mimic the thermal conditions of the use environment of the product, including internal power dissipation within the grid array components, as closely as practically possible. The test acceleration comes from two measures taken: (1) controlled reduced dwell times at the cyclic temperature extremes, thus allowing a higher cyclic frequency, and (2) a controlled increased CTE-mismatch between the components and the test circuit board by an increase in the coefficient of thermal expansion (CTE) of the test circuit boards relative to the product circuit boards. Control test vehicles with product-like circuit board construction were also utilized. The results from the different test vehicle configurations are correlated and utilized to estimate the reliability of the product in the field