Hi!

Good points! Just add something more. I think your colleague Ken Sautter point
out something interesting about the solvent. I assume the same will happen to
the moisture in the photoresist, which is important for the speed of develop
process. That is why somebody hold their sample for a long period for the thick
photoresist process. I think the name is rehydration.

Hopefully this helps!

Best regards,
Ningyuan Wang

> Date: Thu, 19 Aug 2010 13:37:07 -0700
> From: BMoffat@yieldengineering.com
> To: mems-talk@memsnet.org
> CC: KSautter@yieldengineering.com
> Subject: Re: [mems-talk] Hard vs. Vacuum Contact Lithography
>
> Zak,
>
>     Great question.  You did not say positive or negative resist.  I
> guessed positive.  My first input hard contact implies sometrapped air
> and the UV exposure breaks down the oxygen in the trapped air to Ozone
> and or oxygen plasma.  If Ozone it eats the resist and gives thinner
> resist so faster develop.  If Oxygen plasma it eats the resist and the
> olasma has a strong UV component so it exposes harder and you get faster
> develop.  Colleague Ken Sautter says probably easier  Vacuum exposure
> pulls solvent out of resist giving denser resist longer develop.  At
> least 3 possibilities.
>
> Bill Moffat