etching high aspect ratio vias using STS etcher

[Steve Zhuang]

Dear labmembers,

Does anyone have experience in etching high aspect ratio vias using STS or 
STS2 etcher?  I'd like to etch 20-um diameter, 400-um deep vias on an SOI 
wafer, and the etching would stop at the burried oxide layer.  Is this 
doable?  Which recipe is best suited for this particular process?

Any input will be highly appreciated.

Thanks a lot!!

Steve Zhuang
Khuri-Yakub Group