METHOD OF WAFER MARKING FOR MULTI-LAYER METAL PROCESSES

摘要

A new method of forming a laser mark without damage to the wafer surface is described. A pad oxide layer is formed on a silicon wafer. A nitride layer is deposited overlying the pad oxide layer. A first trench is laser cut through the nitride layer and the pad oxide layer into the silicon wafer. The trench is etched to a second depth wherein the nitride layer is used as a hard mask and wherein the trench forms an identification mark.