new process by using 3 % NaOH

Mary Tang mtang at snf.stanford.edu
Thu Sep 8 12:09:55 PDT 2005


Hi Paul --

Good question.  The hazardous waste should be labelled appropriately by
the user.  Since he says he's done it before and it's stable, I'm perhaps
presuming that he knows what he's doing.  But you're right -- we should
ask because it's possible that the waste may require special attention
(like it might explode if it isn't addressed in time -- this actually
happened to some people in the lab above mine when I was in grad school
-- blew out a bunch of windows and trashed the chemical bench, though
luckily no one was seriously injured.)  We can ask him.

M

On Thu, 8 Sep 2005, Paul Rissman wrote:

> I agree with Mary.  Don't we need to know what will be etched for disposal 
> reasons?
> 
> At 11:02 AM 9/8/2005, Mary Tang wrote:
> >Hi all --
> >
> >I think this, in general, sounds OK.  The conditions that would make me
> >feel better are:
> >
> >1.  Waste be collected locally and properly labeled for disposal (this
> >sounds like a lift-off process, and as we don't know what the materials
> >are, I don't feel comfortable putting it down the AWN.)
> >
> >2.  Mixing should be done outside the lab.  We should reiterate the
> >procedures and policies for transporting chemicals to SNF, especially as
> >I'm not sure who this is, much less that he is aware of these policies in
> >practice.
> >
> >How do these sound to you?
> >
> >Mary
> >
> >On Thu, 8 Sep 2005, Mr Liangliang Li wrote:
> >
> > > Dear Sir/Madam:
> > >    How are you?
> > >    I want to use 3% NaOH solution to strip the resist off from an 8-inch
> > > substrate, I hope I can get your permission. the following is the detailed
> > > process I want to do on the wet bench general:
> > >
> > >    1: I will get my own 3% NaOH solution and transfer it into the 
> > cleaning room
> > > to the wet bench. I will mix NaOH powder with water or dilute 50% NaOH 
> > solution
> > > outside of the cleanining room, to get 3% solution.
> > >    2: I will get a large beaker (9 or 10 inch round size and 6-8 inch 
> > tall) and
> > > bring it into the cleaning room.
> > >    3: one 8-inch Printed circuit board substrate with a mask (made of 
> > negative
> > > resist) on the top surface will be shipped from Intel. In our own lab, my
> > > magnetic material will be deposited to cover the whole substrate. And 
> > then, I
> > > will bring the substrate to the wet bench.
> > >    4: in the wet bench general, I will soak the 8-inch substrate into 
> > the 3%
> > > NaOH solution inside the big beaker and heat to 45 degree C for 30 
> > mins. The
> > > resist will be stripped off from the substate.
> > >    5: After stripping, I will clean the wet bench and waste accordding 
> > to the
> > > manual, the 8-inch substate will be taked out of the cleaning room 
> > immediately
> > > and shipped back to Intel.
> > >
> > >    In our own lab, I have tested the stability of the substate in 3% NaOH
> > > solution at 45 C. It is really stable. The hot plate size is 8 inch by 
> > 8 inch
> > > and the tank is 11-12 inch size. So we have enough space.
> > >
> > >    Dear Sir/Madam, if you think this process is ok in the wet bench 
> > general,
> > > please let me know.
> > >    Thank you very much
> > >
> > > best regards
> > > liangliang li
> > >
> 




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