Gas mixture for etching a polysilicon electrode layer and etching method using the same

摘要

A gas mixture for etching a polysilicon electrode layer in a plasma etching apparatus, and a method for etching the electrode layer using the same. The etching gas mixture is a mixture of Cl2 gas and N2 gas, wherein the N2 gas is in the range of about 30% by volume of the total volume of Cl2 gas and N2 gas combined. In the electrode layer etching method of the present invention, the polysilicon electrode layer is formed on a semiconductor substrate. A mask pattern of an oxide or photoresist is then formed on the electrode layer. The electrode layer is etched using a plasma formed by the gas mixture of Cl2 gas and N2 gas, with the mask pattern functioning as an etching mask. An upper power source of the plasma etching apparatus delivers power in the range of about 500 to 1000 W, while the etching gas mixture is formed by supplying Cl2 gas at a rate of about 100 to 400 sccm, and N2 gas at a rate of about 3 to 15 sccm.