From the SEMI wafer standard spec (SMEI M1-0701), a {100}, n-type,
150 mm diameter silicon wafer should have a secondary flat at 135
degrees CW from the primary flat (effective January 1, 1990).
On Mar 22, 2006, at 2:47 AM, polly wrote:

>
> Dear Sir
> I have a query regarding the WAFER FLATS. I HAVE A WAFER WHOSE
> PRIMARY FLAT IS AT AN ANGLE OF 135 DEGREE WITH SECONDARY FLAT I
> DONT KNOW ITS TYPE OR ORIENTATION