Study on Wafer De-Chuck for High Aspect Ratio Etch Process

Higher aspect ratio feature etch is required with the increase of the layer count in 3D NAND technology. The arcing frequency in high aspect ratio etch process increases because charge accumulates due to the high power and more polymer deposition in the process. Thus, it is essential for the etching tool configure optimization to avoid arcing occurrence. In this study, we found that the helium detection for De-chuck charge release has high risk of arcing, while the soft-lifted pin charge release detection has wider window in avoiding the arcing happening. To acquire additional margin, the De-chuck parameters are optimized for healthier mass production.