| 摘要 |
A dry etching method by which the surface of a variety of materials constituting a semiconductor device may be planarized or smoothed under clean state. Small-sized recesses existing on the surface of a layer of the material to be etched are filled with deposited free sulfur yielded from sulfur halides, such as S2F2 or S2Cl2, into the plasma under conditions of dissociation produced by electrical discharge. After the surface of the material to be etched is planarized in this manner, etching is carried out under conditions of simultaneously removing the small-sized projections and deposited sulfur to successfully eliminate step differences or roughness on the material surface. Etching may alternatively be carried out under the condition of competition of filling of recesses with sulfur and removal of the projections. Sulfur may easily be removed on sublimation by heating the wafer after completion of etching without producing pollution by particles. The present invention may be applied to trimming of cross-sectional shape of the trenches or connection holes, surface smoothing of the WSix layer formed by high temperature CVD or planarization of an interlayer insulating film used for covering the step differences.
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