| 摘要 |
PURPOSE:To eliminate the possibility of having an overetching as well as to unnecessitate a strict control by a method wherein a dry etching is performed on a silicon nitride film using reaction gas formed by mixing sulfur hexafluoride and methane difluoride. CONSTITUTION:A dry etching is performed on a silicon nitride film using reaction gas formed by mixing sulfur hexafluoride and methane difluoride. When an etchin is going to be performed, silicon nitride is etched by sulfur hexafluoride, but on the other hand, when silicon dioxide is exposed, the carbon component generated by the decomposition of methane difluoride is adhered to the surface of the methane difluoride, a coating is formed, and sulfur hexafluoride performs the action wherein the etching on the silicon dioxide is prevented. Accordingly, the silicon nitride film can be removed easily by the improvement of selectivity of reaction gas when a dry etching is performed, thereby enabling to manufacture the semiconductor element of good quality.
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