Cu 박막과 SiO₂ 절연막사이의 TaNₓ 박막의 접착 및 확산방지 특성

Adhesion and Diffusion Barrier Properties of TaNₓ Films between Cu and SiO₂

Formation of an adhesion/barrier layer and a seed layer by sputtering techniques followed by electroplating has been one of the most widely used methods for the filling of through-Si via (TSV) with high aspect ratio for 3-D packaging. In this research, the adhesion and diffusion-barrier properties of the TaNₓ film deposited by reactive sputtering were investigated. The adhesion strength between Cu film and SiO₂/Si substrate was quantitatively measured by 180° peel test and topple test as a function of the composition of the adhesive TaNₓfilm. As the nitrogen content increased in the adhesive TaNₓfilm, the adhesion strength between Cu and SiO₂/Si substrate increased, which was attributed to the increased formation of interfacial compound layer with the nitrogen flow rate. We also examined the diffusion-barrier properties of the TaNₓfilms against Cu diffusion and found that it was improved with increasing nitrogen content in the TaNₓfilm up to N/Ta ratio of 1.4.