Return to fab after processing at SMI

[Samuel B. Schaevitz]

Hey All,

I have some wafers which have been through processing at SMI (Silicon 
Microstructures, Inc. in Milpitas), that I would like to bring back into 
the fab as clean wafers.

The wafers have no metals or other non-standard materials on them. These 
wafers have been through 3 steps at SMI: photo processing, plasma etching, 
and wet oxidation.

The photo is done in an area which also processes Au wafers. This is 
similar to SNF's policy, so I do not see why this would be a problem.

The plasma etching consists of a SiN etch in a Tegal parallel-plate etcher, 
followed by a resist strip in a Branson barrel asher. Au is not etched in 
either machine, however Au-coated wafers are allowed in both machines.

The final step at SMI is a diffusion clean in NH3OH:H2O2 and HCl:H2O2 (SC-1 
and SC-2), followed by a wet oxidation at 800C in a furnace. Au is not 
allowed into either the diffusion clean or the furnace.

I believe that the final clean in the diffusion bench should eliminate any 
possible contact contamination in the metal etchers.

If SNF will not accept these wafers as "clean", then I would like to 
specifically request that these wafers be allowed into the following equipment:
All Au-contaminated equipment, including the photo area
drytek2
amtetcher
stsetcher
matrix

Thank you,
Sam

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Samuel B. Schaevitz
Lilliputian Systems, Inc.
46560 Fremont Blvd, Suite 419
Fremont, CA 94538
Cell: 617 543-5875
Office: 510 656-5999
Fax: 510 656-4999

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