Evaluation of Direct Copper CMP on Spin-on Low k Materials

摘要

The purpose of this study is evaluated the impact of the direct copper CMP processes to the low k porous SiLK dielectric resin film (k = 2.23 ) and the Ensemble CS dielectric solution film (k = 2.9) as the CMP stop layer. These two films as well as a stack of both films were polished at different process conditions with varied copper barrier CMP consumable sets. The removal rate ratios, film surface and bulk properties were investigated before and after CMP processes. It was found that the direct CMP processes had no impact on the mechanical property and electrical properties for porous SiLK dielectric resin and Ensemble dielectric solution films. However, there was difference in film surface properties after polishing processes with different consumable sets, especially in surface roughness. Therefore, it is critical to choose the adequate consumable sets to achieve better surface properties.