Patent ID: 9460897
Filing Date: 2016-10-04
CPC Classification: H01J,H01L

Claim Text:
1. A plasma etching method for etching a processing target film formed on a silicon substrate using a silicon film formed on the processing target film as a mask, the plasma etching method comprising: performing a first etching to etch the processing target film, in which an oxide film and a carbon film are alternately laminated, to a position of the processing target film in a film thickness direction by plasma of a mixed gas containing (i) a first CF-based gas in which a content ratio of C (carbon) in relation to F (fluorine) is predetermined and (ii) an oxygen gas; after performing the first etching, changing the first CF-based gas to a second CF-based gas in which a content ratio of C (carbon) in relation to F (fluorine) is higher than the predetermined ratio of the first CF-based gas; and performing a second etching to etch the processing target film from the position of the processing target film in the film thickness direction by plasma of the mixed gas containing the second CF-based gas and oxygen gas.