Hi Yuangfang,
Recently I did some experiments on the anisotropic etching on both sides of
the wafer.
At the 'intersection' of the piramides I found some material can be present,
if the masks are well aligned.
If you like I can send you an abstract of the paper I wrote on these
experiments, which I will present in september.
Regards,
Warner

________________________________________________________________
Warner J. Venstra                                       Delft University of
Technology
PhD student                                             Mekelweg 2
Department of Mechanical Engineering    2628CD Delft
                                                                The
Netherlands
                                                        tel: +31 (0) 15 27
86586
                                                        fax: +31 (0) 15 27
83910

w.j.venstra@wbmt.tudelft.nl

> -----Original Message-----
> From: Gao, Yuanfang  (UMC-Student) [SMTP:ygfff@mizzou.edu]
> Sent: Friday, August 09, 2002 5:17 PM
> To:   mems-talk@memsnet.org
> Subject:      [mems-talk] KOH etching from both sides
>
> Hi, folks,
>
> A question about KOH etching. If two exactly co-centered squares are
> opened on both sides of a DSP 100 nitride coated wafer, the sizes are
> different, but the etching deepth will overlap with each other, and a
> through hole is expected. The question is what happens at the intersection
> point of the two piramid hole? Will the sharp edges be etched away or well
> kept? If there is misalignment of the two square holes, then what will
> happen at the meet point?
>
> Any idear is appreciated, esp. those direct experiences on this.
>
> Y. Gao
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