Do you mean the wagon wheel mask for finding the required etching
parameters? If so 'Silicon Machining' Elwenspoek & Jansen (Cambridge
University Press, 1998) makes mention of it. There are some formulae but
they really need the diagram which is on page 17 of the book. This seems to
be only necessary where the substrate has multiple orientations on the
surface to be etched.
Hope this helps.
Daniel

-----Original Message-----
From: Duan [mailto:brokenspoon@gmail.com]
Subject: [mems-talk] Could someone tell me where I can get some
informationabout wagon wheel pattern?

Such as how big are those spikes? and how many spikes are included in
one wagon wheel pattern? and normally how deep will going to be
etched?