Preliminary results on Cu diffusion through grain boundaries of thin ion-plated AgSn films

Abstract

The diffusion process of copper through grain boundaries of 500 nm thick ion-plated Ag-12at%Sn films was studied in the temperature range 100–250°C. The method is based on the determination of the time of first appearance of Cu on the AgSn surface using Auger electron spectroscopy for determining trace amounts of Cu. An activation energy of E a = 0.53 eV and a diffusivity of D′ o = 1.3 × 10 −7cm 2s −1 was obtained. For comparison, diffusion studies of Cu through ion-plated pure Ag layers have been performed. In this case an activation energy of E a = 0.68 eV and a diffusivity of D′ o = 2.3 × 10 −5cm 2s −1 have been found.