| 摘要 |
PURPOSE:To prevent the influence of a dry etching one step before by plasma- ashing each time the etching is finished. CONSTITUTION:After a first etching is finished, the supplies of high frequency and reactive gas are stopped, oxygen gas into an etching reaction chamber is then supplied, a high frequency (13.56MHz) is supplied, and an ashing with plasma discharge is performed. Reactive product of reactive gas with a silicon substrate 1 to be etched used for a first etching, an organic reactive product including a photoresist of a mask for etching, adhered on the inner wall of an etching reaction chamber or the substrate 1 to be etched by the plasma- ashing are evaporated by oxidizing or ashing to be evacuated to be removed by a vacuum pump. Then, a second etching for patterning a polycrystalline silicon film 3 of lower layer is executed. Further, after the second etching is finished, plasma-ashing with oxygen gas is similarly performed.
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