Plasma etching method and plasma etching apparatus

摘要

Provided is a plasma etching method of etching OCOC film in which HTO films and carbon films are alternately laminated by plasma of mixed gas containing first CF-based gas or second CF-based gas and oxygen gas using a silicon film formed on OCOC film as a mask. The etching of OCOC film includes a first etching process of etching a region spanning from the top surface to the middle of OCOC film by plasma of mixed gas containing first CF-based gas having a predetermined ratio of content of carbon to content of fluorine and oxygen gas and a second etching process of etching a region spanning from the middle of OCOC film to the lowest layer by plasma of mixed gas containing second CF-based gas having a ratio of content of carbon to content of fluorine, which is higher than the predetermined ratio of first CF-based gas, and oxygen gas.

主权项

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.