new process by using 3 % NaOH

Mary Tang mtang at
Thu Sep 8 11:02:55 PDT 2005

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

How do these sound to you?


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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