Dear Dr Zeng,

The major flat on 3" can be 22.22mm +_ 3.17mm although normally it would
be specified  at 22+_2mm by most operations.
You need to note that for specific tight orientation dependant
processing, you would need to specify a very tight major flat
orientation of +_0.1 or +_0.2 degree ( best commercially available) as
normally the major flat would be +_1.0 degree or higher, depending on
how you specified it in procurement.
Most use this major flat for their primary orientation reference to
align the mask.

Should you have any other questions, please contact me directly.

Regards.
Ken Smith

Hongjun Zeng wrote:
> 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
>
>
>
>
> _______________________________________________
> [email protected] mailing list: to unsubscribe or change your list
> options, visit http://mail.mems-exchange.org/mailman/listinfo/mems-talk
> Hosted by the MEMS Exchange, providers of MEMS processing services.
> Visit us at http://www.memsnet.org/
>


--


Kmbh Associates
47 Rocket Circle
Rancho Cordova, CA 95742  U  S  A
510-714-5055 Efax- 510 217 4421 or 561 658 6136

High Purity Float Zone and Specialty CZ Silicon  for Power, IR and
Mirror Optics, Optoelectronics, MEMS, SOI, and other Semiconductor
applications. Service in SOI, Polishing SSP and DSP.
Quartz, Glass, Pyrex and Borofloat Wafer Supply. Anodic Bonding. SOG, SOS.