Hi,

Can you provide a more detailed explanation of what you mean by scalloping?
Is it in the oxide and transferred into the silicon at the top of the
structure? Is it the sidewall of the etched silicon over the entire depth of
the etch? What is the finger width and the gap?

Also, what kind of DRIE are you doing? Is it a Bosch-type etch in an ICP
tool, or a Bosch variant in a parallel plate type etcher, or a biased HBr or
chlorine based process?

Peter

-----Original Message-----
From: [email protected] [mailto:[email protected]]
On Behalf Of Shankar Dutta
Sent: Saturday, September 09, 2006 3:25 AM
To: [email protected]
Subject: [mems-talk] DRIE etching

we are trying to do a DRIE etching (~15-20 micron deep) for comb like
structure. the masking layer is 0.3micron oxide layer. we patterned the
oxide layer by BOE etchant. after that we performed the DRIE experiment. but
surprisingly we find some scalopes in etched area, as if it does some
isotropic etching. is this problem related to paterning of oxide layer with
BOE.