Possible contamination of wbdiff and wbnonmetal

Jaime Garate jgarate at snf.stanford.edu
Fri Nov 10 11:23:04 PST 2000


 I have talked to the user responsible for this. Not only for the safety
issue, but for the cross-
contamination issue. He is involve on the clean up. The WBNONMETAL- has
been decontaminate and it is
okay to use. The WBDIFF- still down under decontamination.

(1) You are not allow to dip your metal tweezers at these wet benches at

(2) You are not allow to go from 20:1 or 6:1 on wbnonmetal to a H2S04
dip and 
    HCL dip on wbdiff at all!!!

(3) We are all members so please follow the procedures and work safely.

Thanks, Jaime Garate

Amol Ramesh Joshi wrote:
>         Hi,
>         Today I found a user doing nonstandard 'cleaning' on wbdiff and
> wbnonmtal. He was etching oxide in 20:1 BOE and 6:1 BOE on wbnonmetal and
> H2SO4 dip and HCl dip on wbdiff. He was holding just one wafer with teflon
> tipped METAL tweezers, no cassette! As most users know, teflon on green
> tipped tweezers tends to wear out after some use. So there is a very high
> chance that metal may have entered the pots I mentioned above. I do not
> need to mention safety issue, no matter how careful one is. I have
> shutdown wbdiff and wbnonmetal.
>         - Amol

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