Hi Vijay,

I've made 2" wafer samples from 4" wafers using anisotropic wet etching.
Just mask off both sides, open a ring of whatever diameter on the back
side, and etch (soak) for a few hours until the new wafer is cut out.
You could even pattern a flat if you want one.  The edges of the "new"
wafer will be a little sharp, but you could lightly sand it if it were an
issue.  I assume your wafers are very special, to go through this
trouble..

Dicing would be easier, but you would need to work with squares..

Good luck!

---Chris

Christopher C. Striemer, Ph.D.
Research Associate
Department of Electrical and Computer Engineering
University of Rochester
Rochester, NY 14627

Date: Tue, 12 Jun 2007 17:53:13 +0200
From: Vijay 
To: mems-talk@memsnet.org
Subject: [mems-talk] Wafer size reduction

Dear All,

I need to urgently reduce the size of my 8 and 6 inch wafers into 4 inch
ones. Could you please let me know if any such services (mechanical or
laser-based wafer cutting) are offered (/available) in Europe ? I guess
wafer edge trimming might also be necessary.

Many thanks in advance,
Vijay