A new etching chemistry for carbon hard mask structures

An investigation was made to determine whether methane (CH4) could assist with polymer formation during fabrication of amorphous carbon hard masks. The results indicated that when CH4 is added to a simple O2/N2 chemistry superior sidewall profiles are seen. Profiles can be modified by addition of extra methane or by an increase in low frequency RF power. Subsequent tests with the simpler CH4/O2 chemistry showed similar profiles could be obtained suggesting this chemistry may also be suitable for etching carbon.