(Digital Presentation) Research on Single Wafer RCA Clean in High Aspect Ratio Trenches

High aspect ratios trench are commonly used in shallow trench isolation (STI) or Gate Poly-silicon structures by dry etching of a silicon substrate. During the dry etching process, polymerization residues are produced inside the trench. These polymerization residues must be removed before the next deposition process. Watermarks might also form by poor drying after the wet cleaning process of high aspect ratio structures, which can seriously affect the next process. In this paper, we show the performance of single wafer RCA cleaning technology in high aspect ratio structures. Polymer residues can be removed by diluted HF and SC1 with megasonic technology, without the appearance of watermarks after drying. This study focuses on polymerization residues and watermarks using inline defect detection to qualify the performance of single wafer RCA clean. Yield is the final verification for proving the single wafer RCA clean.