3" - no idea
4" - primary flat length = 32.5 mm
6" - primary flat length = 57.5 mm

http://microlab.berkeley.edu/labmanual/chap1/1.9.html

-Sunil Kumar
MuSquared, Inc
----- Original Message -----
From: "Hongjun Zeng" 
To: 
Cc: 
Sent: Thursday, February 27, 2003 2:05 PM
Subject: [mems-talk] crystalline direction alignment


> Dear colleagues,
>
> A basic question. How did you align the mask along the crystalline
> direction, i.e., <110> on the wafer? Right now we only have the way to
align
> a straight in mask with the primary flat. Any more precise way?
>
> Second, anybody knows precisely how long is the primary flat of a n-type
or
> p-type 3 inch 100 wafer?
>
> Thanks a lot,
>
> Hongjun Zeng, PhD
> Microfabrication Applications Laboratory (MAL)
> University of Illinois at Chicago
> ERF Building, 842 W. Taylor Street
> Chicago, IL 60607-7022
> Room 3014 ERF
> Tel.: 312-413-5889, Fax: 312-996-6465
>
>
>
>
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