Hi Ciro,

We also have a MA6. I never tried what you did, mainly due to the
following issue: We have small substrates. If you contact, release and
contact them again you see normally that you have a small disalignment
due to substrate shift upon releasing.

One possibility for your problem is: Expose, then develop it by e.g. 1/3
of the developing time. Now you can see the first exposure and may align
accordingly. Normally the resists are quite robust, so the second
exposure and developing (100% of normal time) work nicely. This even
works in the inverse process, however not as good. In both cases, this
requires more work by you, but if it is just for testing purposes, give
it a try.

Best
Daniel

-----Original Message-----
From: mems-talk-bounces+d.grimm=ifw-dresden.de@memsnet.org
[mailto:mems-talk-bounces+d.grimm=ifw-dresden.de@memsnet.org] On Behalf
Of Ciro Chiappini
Sent: Thursday, February 17, 2011 12:43 AM
To: General MEMS discussion
Subject: [mems-talk] K. SUSS MA6 Double exposure

Hello

I need to run a double exposure in vacuum contact mode with a K. Suss
MA6 tool. The two exposures must be shifted by roughly 5 microns, but
I don't have a way to visually align them.

The process I was going to run was: load, WEC, bring wafer to contact,
expose, bring back to alignment separation, slide 5um on the
micromanipulator, bring to contact, expose, unload.

If I run the standard exposure sequence, after the first exposure the
tool requires to unload the wafer (and thus I'll lose my rough
alignment)

The easiest way I see to accomplish this is to use the light intensity
check button on the tool, that allows to operate the UV light
independently. Unfortunately that button is not functional while a
substrate is present.

Has anyone ever been able to override the standard exposure sequence on
an MA6?

I Have easily run this protocol on an EVG620 with the low level IO,
but I need to expose 600nm features and our EVG620 cannot resolve
them.

Thanks for your help.