Hi Bin,

You might not have enough of XeF2 gas to react with Si. Try to reduce the cycle
time such as 1 min and run the etching for many cycles. On the other hand, The
total area needed to be etched may be large which causes the slow etch rate as
well.

Best,

Joseph

--
ChungHao Chen (Joseph)
Research Assistant
Purdue University
School of Electrical and Computer Engineering
EE Building Box 114
465 Northwestern Avenue
West Lafayette, IN 47907-2035
email: chen170@purdue.edu



Quoting Bin Liu :

> Dear All,
>
> I plan use XeF2 etch silicon. The XeF2 is designed to go through several
> 3*5um holes of photoresist and then etch away the silicon underneath. I
> want the etched area to be 20um in radius. I heated up the XeF2 to
> 75C-95C during the etching process, the pressure during etching is
> around 4 torr, I flush the XeF2 every 10 min, and got the sample sitting
> in the gas for 40 min, but I still get very limited etching area through
> the holes. I wonder if anyone have experience on XeF2 etching silicon,
> can you give me some suggestion? the temperature? the pressure? or is it
> because the holes are so small that limit the etching area?