Method for removing Si-needles of wafer

摘要

This application is about a method for removing the deep trench Si-needles on a wafer. The method includes steps of forming a photoresist layer on a frontside surface of the wafer, removing a specific area of the photoresist layer for exposing the Si-needles, proceeding a first etching and a second etching, and finally removing the photoresist layer on the frontside surface of the wafer. The first etching is a wet etching for removing the Si-needles by an etching solution etching from a backside surface of the wafer back to the frontside surface of the wafer. And, the second etching is a dry etching for removing the residual silicon nitride (SiN) slices formed during the first etching.