Subject: Notice on reports of differences in the 5% 950K PMMA -A spin thicknesses.
From: James Conway <>
Date: Fri, 10 Nov 2006 11:12:35 -0800


On the most recent batch of 2% 950K MW PMMA in anisole delivered from
Microchem I have been alerted to a change in the spin speed to film
thickness characteristic.  This may also be the reason that one user have
reported a change in the dose to clear having increased slightly.

Request that all users to be vigilant,  to carefully measure their thin
films after spinning and soft bake, and to report their thickness and dose
to clear determinations to the mail list.

I have inspected the bottle in the Lab and it appears normal with no evident
gelation or solids having been formed.  Viscousity appears also to be

I will be calling microchem in Mass. to see if they have other people
reporting any changes in their material.