Author(s)

R. Das & H. Lu

Abstract

Thermal fatigue life estimation based on CASE failure criterion with measured solder layer strain R. Das & H. Lu Department of Mechanical, Aerospace and industrial Engineering Ryerson University, Canada Abstract Thermal fatigue of interconnects is a common root cause of failure for microelectronics. The estimation of cycles to failure for a solder layer or joint is one of the critical requirements in the development of reliable electronic packages. For an assembly, the thermal-mechanical strains are induced mainly due to the temperature non-uniformity and the mismatch of Coefficients of Thermal Expansion (CTE) at multi-material joints. Temperature cycling results in stress cycling that in turn, causes fatigue damage to accumulate in the solder joints. Many previous studies have reported that the solder deformation due to the combination of plastic and creep is much larger than the values expected from a simple calculation based on the thermal expansion mismatch. And the time-dependent creep o

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