Subject: Re: zep520a
From: "Deji A." <>
Date: Wed, 18 Jul 2007 11:17:19 -0700

From my previous experience, using the zep520a diluted solvent at the very bottom of the bottle does not give uniform coverage. There might be contaminants, dirt, non-uniform mixing at the bottom of the bottle that degrades the uniformity. I suggest a new dilution bottle should be made available.
Many Cheerz
Deji A.
EE rocks
Nature is the teacher of all things

James Conway wrote:
Dear Deji A. and ZEP-520A users:

Please be sure to record your usage on the side of the bottle's paper box so we can track use of this expensive material. It cost $15./ml to SNF.  A 100 ml bottle is enough for 150 - 200 wafers if used conservatively. Please be sure to spin up several wafers and not necessary just one wafer at a time.  This saves you time and reduces waste.  I normally can spin eight to twelve wafers using a 10 ml syringe that is filled to between 8 - 10 ml level. 

If you are using 1:1 ZEP520A:ANISOLE dilution for thin films below 100 nm thickness -- please use up the remaining material in the small glass jar.  There is sufficient material remaining for ten or more wafers.  You only need ~1 ml to completely cover a 100 mm wafer.  Once that batch is completed we can make up a new batch of 50 ML total.

I have a new bottle of
ZEP-520A material in the stockroom refrigerator -- once the old bottle is finished I will bring out the new bottle.  Please DO NOT DISPOSE OF THE OLD ZEP-520A bottle!

Also available upon request are qualified and measured thin films of ZEP-520A on 100 mm n+ b-prime
Silicon wafers in various thickness from my recent test. Please see me if you desire access to a few of these wafers. I have been getting very nice metal lift off and RIE etching results working with this material.

All the Best,

James Conway

Deji A. wrote:

I am writing coz the zep520a undiluted bottle is almost out of stock the rate i am using it, it will likely be out when you return from fto. Enjoy.
Many Cheerz
Deji A.