| 摘要 |
A method is provided for selectively etching materials on a semiconductor wafer (10, 30) that have similar etch rates. The semiconductor wafer (10, 30) is provided with at least a first layer. An etch mask is provided on the first layer. The layer with the etch mask (13) is partially etched to a predetermined point. A polymer film (21, 38) is deposited on the partially etched layer. The polymer film (21, 38) is etched in an anisotropic manner creating open or clear areas (14, 34) in the horizontal polymer film, while leaving polymer coating (22, 37) on vertical walls (12, 36). The open areas (14, 34) are chemically etched, while the remaining polymer coating (22, 37) on the vertical walls (12, 36) protects the vertical walls (12, 36) from being chemically etched. This method also protects the top surface of the semiconductor wafer.
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