Hi~ I'm trying to make poly-Si deep trench with LAM9400 or AMAT MxP poly etcher. Mininum feature size is 3um and depth is 20um. And vertical profile is needed; over 89¢ª And hard mask for poly etch is PETEOS oxide of 1.5um. Oxide etch will be done with TEL IEM oxide etcher. I'll start with Cl2+O2 gas chemistry for poly etch. If there is anybody who have done similar experience, please give me comment. Best Regard, Sunghon Chi