METHOD FOR PROTECTING BREAK DOWN OF GATE OXIDE

摘要

The method includes the steps of forming a gate oxide film, a poly-Si or/and silicide layer, and a photoresist mask on the Si substrate, and etching the poly-Si or/and silicide layer by a plasma etching method. The etching method includes the steps of main-etching the layer to the end point under the Cl2/SF6/HBr mixture gases circumstance at the predetermined power, over-etching the layer under the Cl2/HBr/He mixture gases circumstance at the power of 225W for 30 sec., maintaining the power to 150-180W for 1-5 sec., and to 100-120W for 1-5 sec., and interrupting the power, to thereby preventing the gate oxide film from being degraded or broken.