Patent ID: 8906248
Filing Date: 2014-12-09
Classification: H01L

Abstract:
1. A method for etching features through a stack of a silicon nitride or silicon carbide layer over a silicon layer over a silicon oxide layer in a plasma processing chamber, comprising: etching the silicon nitride or silicon carbide layer in the plasma processing chamber, wherein the silicon nitride or silicon carbide layer is disposed below a silicon oxide layer, the etching comprising: flowing a silicon nitride or silicon carbide etch gas into the plasma processing chamber; forming the silicon nitride or silicon carbide etch gas into a plasma to etch the silicon nitride or silicon carbide layer; and stopping the flow of the silicon nitride or silicon carbide etch gas; etching the silicon layer positioned directly below the silicon nitride or silicon carbide in the plasma processing chamber, comprising: flowing a silicon etch gas into the plasma processing chamber that is different than the silicon nitride or silicon carbide etch gas and wherein the silicon etch gas comprises SF forming the silicon etch gas into a plasma to etch the silicon layer; and stopping the flow of the silicon etch gas; and etching the silicon oxide layer positioned below the silicon layer that is below the silicon nitride or silicon carbide layer in the plasma processing chamber, comprising: flowing a silicon oxide etch gas into the plasma processing chamber that is different than the silicon etch gas; forming the silicon oxide etch gas into a plasma to etch the silicon oxide layer; and stopping the flow of the silicon oxide etch gas, wherein the etching the silicon nitride or silicon carbide layer etches most of the silicon layer.