A reliability model for interlayer dielectric cracking during temperature cycling

The temperature cycling performance of three different mold compounds is compared using a device known to experience interlayer dielectric cracking. The cumulative failure rate is represented well by a Weibull distribution. The distribution parameter is the same for the three mold compounds and stress ranges studied. The location of the failure rate curve with respect to the number of temperature cycles is found to follow a power law formula which is a function of the applied stress. It is concluded that the difference in temperature cycle performance of the three mold compounds studied can be explained on the basis of the stress applied to the die surface which is controlled by the elastic modulus and thermal expansion coefficient of the plastic and the coldest temperature of the cycle.<>