| 摘要 |
PROBLEM TO BE SOLVED: To provide a plasma etching method by which a silicon nitride film can be selectively and quickly etched and can be etched to have high anisotropy.SOLUTION: In a plasma etching method, a silicon nitride film 203 arranged on a polysilicon film 204 is plasma etched using a resist 201 as a mask. The plasma etching method includes: a first step of etching the silicon nitride film 203 until the polysilicon film 204 starts to be exposed; and a second step of etching the silicon nitride film 203 after the first step using mixed gas composed of CHF gas and COgas. The ratio of the flow rate of the COgas to the flow rate of the CHF is 1 or less. |
