Evaluation Methods of Fundamental Properties and Reliabilities of Joining Materials for Power Semiconductor Devices

Abstract

We studied a method of evaluating joining materials for power semiconductor device packaging such as Ag sintering materials. For the fundamental properties, Young's modulus values were measured by three-point bending tests using joining materials deposited on thin Cu plates. Coefficients of thermal expansion were evaluated by warpage of the same samples using a Shadow Moiré measurement in an electrical furnace over a range of temperatures from 25°C to 250°C. Power cycling tests were performed using an Al plate contacted on the upper electrode of SiC diodes to avoid any effects from the other packaging materials. Electro-migration reliability tests were carried out by joining materials deposited on metalized Al₂O₃ substrates with high current densities.