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.

Wafer Cross-Section at Edge:Before Edge Trim: After Edge Trim: Film buildup Clean edge ↓ ╱──────────╲ ╱──────────╲ ╱ ╲ ╱ ╲ │ WAFER │ │ WAFER │ ╲ ╱ ╲ ╱ ╲──────────╱ ╲──────────╱ Edge bead risk Particle-free handling

Edge Trim Methods:
| Method | Application | Removal |
|--------|-------------|---------|
| Chemical (EBR) | Photoresist | 1-3mm |
| Wet trim | Metal films | 2-5mm |
| Bevel polish | CMP pre-treatment | Edge only |

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