Methodology for a highly accelerated solder joint reliability test

A Thermo-Mechanical Deflection System (TMDS) test method has been developed for evaluating the fatigue performance of solder joints in printed circuit board (PCB) assemblies. The TMDS test imparts cyclic twisting deflections on an assembled PCB test vehicle which is tested under controlled iso-therm al conditions in a thermal chamber. Tests were conducted at various angles of twist and isothermal conditions at 100 degreesC and 25 degreesC. Failure analysis using SEM showed that the solder joint failure for the TMDS test is comparable to the failure mechanisms for ATC test failures for solder jo ints. Weibull failure distribution plots for TMDS and ATC tests were compar ed and a Scale Factor (SF) was used to correlate the test result.