A Study on the Fluid Flow for Effective Polishing Process in CMP Equipment

Abstract

The CMP (Chemical Mechanical Polishing) process is an essential process in the semiconductor manufacturing for MLM (Multilevel metal) with high-integration of devices. The targets of CMP process are such as: obtaining the uniform polishing rate on the wafer surface and high-grade flatness in each chip and removing the foreign substances with uniform cleaning. However, as the wiring density increases and the wafer size becomes larger for MLM structuring, some problems have been encountered such as: size of the CMP equipment, non-uniformity of the slurry distribution. The CMP in this research supplies the slurry from 12 nozzles for polishing process and it is important to decide the locations and the flow rates of the nozzles. In this research, we verified that the polishing rate on the wafer is related with the uniformity of slurry distribution. The locations of the slurry nozzles are investigated to distribute the slurry uniformly on the polishing pad using numerical analysis. The results of the research were applied to manufacture a revised CMP equipment.