Hi,
I am trying to etch Nb with SF6. I noticed that there is lot of polymer
formation on the Si Substrate surrounding my desired Nb feature. I was thinking
of using SF6+O2 to avoid polymer formation. Adding O2 to SF6 means photoresist
will be etched at a greater rate. It also means that polymer which is most
likely acting as a etch stopper for Si will in its absence cause Si to etch
faster, which is even more detrimental because it will end up in making a big
trench next to Nb feature.(I already noticed the Si etch of 500nm in 4 min)
Any alternative that anybody knows to avoid Si etch?????
Thanks!
~T