Hi,


I ran BOSCH process on a ICP-DRIE system to make some high-aspect-ratio
structure by etching through a 400 micron thick single crystal Si (110)
wafer. The structure turned out to be very brittle and can't withstand
perturbation in horizontal directions. I checked the sidewalls and found
they are pretty rough and there are many straw-like features in vertical
directions (from the top to bottom). I think they result in serious stress
concentration and cause this problem.

I was wondering if there are some methods or post-process which could make
the sidewalls smoother. Please let me know if you have some suggestions or
comments. Thanks!



Best Regards,


Qing Yao
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M&IE @ UIUC