Importance

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Abstract

A method of etching a silicon-containing layer 170 on a substrate 45 comprises the steps of placing the substrate 45 on a support 75 in a process chamber 50. The substrate 45 is exposed to an energized process gas comprising a bromine-containing gas, a chlorine-containing gas, an inorganic fluorinated gas, and an oxygen gas. The volumetric flow ratio of the gas constituents is selected so that the energized process gas etches regions 180a,b having different concentrations of dopant in the polysilicon layer 170 at substantially the same etching rate. Optionally, the gas composition is also tailored to simultaneously clean off etch residue from the internal surfaces of a process chamber 50 during etching of the substrate 45.

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First Claim