ALL USERS READ ME!! -- Last bottle of 5 % 495 PMMA in Anisole stocked in the lab
jwc at snf.stanford.edu
Mon Aug 7 11:40:59 PDT 2006
Greetings PMMA Users:
I am very disappointed that I must send out this notice again!
Previous message thread July 25, 06
Previous message thread March 15, 06
Every Friday before I leave for the weekend, I check the PMMA and Ebeam
resist supplies in the Cleanroom.
I checked the PMMA's supplies in the SNF Cleanroom at 5 PM last Friday
and there was ~ 30 ml or more of 5% 495K PMMA in anisole remaining in
that bottle. This is enough for 20 - 25 wafers! There was also a spare
75 - 100 ml of 5% 495K PMMA in anisole remaining in an additional
bottle with my name on it for emergency back up.
Saturday evening Hemanth came in the Lab to discover a empty 5% 495K
PMMA in anisole and that the spare bottle was also missing.
A search of the lab did not recover the missing bottle and I can only
now surmise that it was taken out of the SNF cleanroom.
We have also consumed nearly a liter of 5% 495K PMMA over the course of
the last month. A 250 ml bottle of 5% 495K PMMA in anisole would last
two to three months in normal usage as per our past PMMA inventory logs.
Recently this volume has been consumed in a week to ten days! There
have not been nearly enough exposures in the Ebeam lab to account for
this level of usage of PMMA! Clearly it is being handled
inappropriately by untrained users, being wasted as some users may be
not using syringes to dispense these materials, or simply be taken from
the SNF cleanroom.
I have just restocked the last remaining 250 ml bottle of 5% 495K PMMA
in anisole into the cleanroom. I ordered the last supply source bottle
7-25-06 and it shipped last Wednesday. We may run out of PMMA before it
arrives -- if users are not following proper dispense methods
established for the lab.
ALL Users are requested to review the Ebeam resist handling procedures
to review the proper methods to handle these materials.
ALL Users are instructed to be frugal in their usage of these
materials, make an effort at all times to minimize waste, and never are
any chemicals or engineering materials to be taken out of the SNF
cleanroom for any purpose whatsoever.
This will be the third and last warning I will make on this topic:
If usage of PMMA materials does not return to normal acceptable levels
-- I will change the method in which we supply and control the usage of
these expensive engineering materials and will require all users to
check out each volume of material individually and at greater expense to
all lab members.
Users as a Community are also requested to be vigilant observers and are
instructed to report any User who is taking material from the SNF
Cleanroom and/or not dispensing the material properly using syringes on
the spinners. You suggestions are welcomed.
Thank you for your support,
Hemanth Jagannathan wrote:
> Just wanted to send out and e-mail to everyone to inform you that we are
>out of 5% PMMA in the lab. I came in and search high and low (and at all the
>spinners) and only found a bottle with a few drops remaining.
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