Use of Gloved Hand to Transfer Wafers is NOT Allowed

Jim McVittie mcvittie at cis.Stanford.EDU
Tue Feb 27 18:12:57 PST 2001

Lab Users,

On Sunday I got the following note from one of the senior grad students in
the lab:

>      I wonder if certain lab practices have changed recently. Today I
>found a person trying to transfer wafers from nonmetal cassette to wbdiff
>cassette with just a pair of vinyl gloves. I stopped him from going into
>wbdiff and asked him why wasn't he using plastic tweezers. He said he did
>not want to scratch the wafers which he intended to bond. I suggested
>cassette to cassette dump transfer and he claimed it to be a dirty method
>and thought vinyl gloves out of bag are very clean! It is very easy for
>the clean gloves to touch several dirty surfaces without user knowing
>about it. Apart from that, I observed his method of adding chemicals and
>didn't find it particularly clean either.  Please explain to me and
>entire lab if there are new wbdiff policies in place (which I didn't see
>in last 4 years of my lab work).

There is long standing lab policy to never touch wafers during processing
with your hands with or with gloves on. Without gloves one contaminates
the wafers with finger oils which are loaded sodium and impossible to
completely remove. With gloves one still contaminates the wafers with
glove residues and particles picked up from previous surfaces touched the
gloves. Please follow the lab rules in processing your wafers. There are
good reasons for the rules and are consequences for not following them.

	Thanks,		Jim 	
James P. McVittie	                Senior Research Scientist
Allen Center for Integrated Systems     jmcvittie at
Stanford University             	Tel: (650) 725-3640	
Rm. 336, 330 Serra Mall			Fax: (650) 723-4659
Stanford, CA 94305-4075	

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