Temperature-cycling acceleration factors for aluminium metallization failure in VLSI applications

Low-cycle fatigue data for four common aluminium failure mechanisms in VLSI applications are presented; fractured intermetallic bond failure, chip-out bond failure, shear-stress-induced metal movement and passivation cracking and tensile-stress-induced metal notching and voiding (stress migration). Except for the tensile-stress-induced notching and voiding, uniform acceleration exists when commonly used accelerated temperature cycling ranges are compared: 0 degrees C/125 degrees C, -40 degrees C/85 degrees C, -40 degrees C/140 degrees C, and -65 degrees C/150 degrees C. Tensile-stress induced metal notching and voiding is not uniformly accelerated by temperature cycling; it is accelerated more effectively by simple elevated temperature storage. A temperature-cycling acceleration factor model, based on the Coffin-Manson law, is presented. The problem of using only the temperature cycling range when calculating the acceleration factor is highlighted.<>