Patent ID: 7122480

Claim:
A method of plasma etching a semiconductor device, comprising: placing the device into a reactive chamber, wherein the device comprises at least two material layers formed over a semiconductor layer; introducing an etching gas comprising a plurality of gases into said chamber; generating a plasma of said etching gas at a first power level and contacting said device with said first power level plasma; generating a plasma of said etching gas at a second power level in said chamber; etching a first of said at least two material layers with said second power level plasma of said etching gas, wherein said plurality of gases have respective flow rates forming a first set of flow rates; subsequently, etching a second of said at least two material layers with said second power level plasma of said etching gas, wherein said plurality of gases have respective flow rates forming a second set of flow rates, said second set of flow rates being different from said first set of flow rates; and, wherein said second power level plasma is a higher power plasma than said first power level plasma.