Comparison of delamination effects between temperature cycling test and highly accelerated stress test, in plastic packaged devices

Two reliability stress tests were performed on, plastic packaged test chips consisting of a temperature cycle test (TCT) of 500 cycles and a highly accelerated stress test (HAST) of 300 h with bias voltage. Before and after the tests delamination of the die-mold interface was examined with scanning acoustic tomography. On these test chips bondwire failures, mechanical deformation, and corrosion test structures have also been measured. It appeared that 300 h of HAST nearly destroyed the adhesion between chip and mold whereas a 500 TCT caused delamination only to initiate from the die corners. The HAST caused a large number of corrosion failures, and the TCT a number of mechanical deformation failures.<>