Temperature cycling and thermal shock failure rate modeling

Combining the Coffin-Manson formula with a lognormal distribution continues to be an effective method to model the effects of thermal stressing upon VLSI IC package reliability. This approach is applied to Thin Film Cracking (TFC) and several other failure mechanisms relevant to IC packages. The Coffin-Manson exponent, m, is found to lie in one of three relatively narrow ranges: m for ductile metal fatigue is /spl sim/1-3 m for commonly used IC metal alloys and intermetallics is /spl sim/3-5, while m for brittle fracture is /spl sim/6-8.