edge trim

**Edge Trim** is a wafer process step that removes material from the wafer edge to eliminate particles, films, or defects that could cause contamination or handling issues. ## What Is Edge Trim? - **Method**: Chemical etching or mechanical grinding of outer 1-3mm - **Purpose**: Remove edge bead, prevent film delamination, reduce particles - **Timing**: After film deposition, CMP, or photoresist coating - **Equipment**: Spin processors with edge-targeted nozzles ## Why Edge Trim Matters Film buildup at wafer edges causes particles during handling and robot contact. Edge trim maintains clean handling surfaces throughout the process flow. ```svg ``` **Edge Trim Methods**: | Method | Application | Removal | |--------|-------------|---------| | Chemical (EBR) | Photoresist | 1-3mm | | Wet trim | Metal films | 2-5mm | | Bevel polish | CMP pre-treatment | Edge only |