| 摘要 |
PURPOSE: A plasma etching method is provided to present a good balance between the etching selectivity and the etching planar uniformity of silicon nitride relative to silicon oxide and silicon. CONSTITUTION: An etching gas is supplied into a process chamber(16) and turned into plasma so as to etch a silicon nitride film(12) arranged on a field silicon oxide film(4) on a wafer(w). A mixture gas containing at least CH2F2 gas and O2 gas is used as the etching gas. Parameters for planar uniformity, by which the etching apparatus is set in light of a set value of the planar uniformity, include the process pressure and the mixture ratio (CH2F2/O2) of the mixture gas. As the set value of the planar uniformity is more strict, either one of the process pressure and the mixture ratio is set higher.
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