Temperature characteristics due to stress-induced migration

Abstract

The stress-induced migration phenomenon causes voids and disconnections in metal interconnections in semiconductor devices during high-temperature storage. This phenomenon is one of the problems related to the reliability of metal interconnections. The following discrepancies with respect to high-temperature storage are found among results reported by researchers concerning the temperature dependence of the interconnection lifetime: maximum failure rate appears at a certain temperature; failure rate increases with temperature; and failure rate is independent of temperature. The reasons for these discrepancies have not been clarified as yet. The purpose of this work is to theoretically clarify the temperature characteristic of stress-induced migration. First, we present the theoretical model for the vacancy behavior due to stress-induced migration. Next, the theoretical model is applied to void formation and disconnection to confirm its validity. Finally, the results of the theoretical analysis are compared with the experimental results of high-temperature storage. We find that the temperature characteristics of void formation change depending on the void interval, and those of disconnection change depending on the void interval and the void radius. The presented model can qualitatively explain that the discrepancies among various researchers’ findings concern the temperature dependence of the interconnection lifetime.