Elimination of Si-C Defect on Wafer Surface in High-Temperature SPM Process Through Nitrogen Purge in 300-mm Single-Wafer Chamber

Abstract

During semiconductor manufacturing, the high temperature sulfuric acid peroxide mixture (SPM) and airborne molecule contaminants (AMCs) can result in the formation of defects such as Silicon-carbide (Si-C) on the wafer surface. Furthermore, defects adversely affect device performance, yield, and manufacturing productivity. In this work, a novel approach is proposed by introducing an additional nitrogen (N2) gas purge nozzle inside the single wafer chamber to reduce total volatile organic compounds (t-VOC). Additionally, we provide insights into the mechanism underlying defect formation in SPM which has not been previously explained. In SPM process, defects are formed by AMCs and high temperature. So, various AMCs were investigated in this work. Moreover, the correlation of the number of Si-C defect with temperature and duration of chemical flow was also analyzed. The experimental results demonstrated that defects and t-VOC follow the same concentration trend. Our nitrogen purge method effectively diluted the chamber environment, reducing the adhesion energy between contamination particles and the wafer surface. A suitable N2 purging rate inside the single-wafer chamber facilitated the elimination of around 63% of defects from wafer surface. Hence, this approach can be crucial in minimizing the Si-C defects and improving the chamber environment for high-temperature SPM wet-cleaning process.