| 摘要 |
The embodiments of methods described in this disclosure for removing a hard mask layer(s) over a polysilicon layer of a gate stack after the gate stack is etched allows the complete removal of the hard mask layer without the assistance of photolithography. A dielectric material is deposited over the substrate with the gate stacks. The topography of the substrate is removed by chemical mechanical polishing first. Afterwards, an etching gas (or vapor) is used to etch a portion of the remaining dielectric layer and the hard mask layer. The etching gas forms an etch byproduct that deposits on the substrate surface and can be subsequently removed by heating. The etching and heating to remove etch byproduct are repeated until the hard mask layer is completed removed. Afterwards, the remaining dielectric layer is removed by wet etch. The methods described are simpler and cheaper to use than conventional methods for hard mask removal.
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