10 min prebake is way too long with 1813. I do 1 min at 115 for silicon
or thin glass and 2 min at 115 for thicker glass slides. When you over
bake the resit becomes less soluble in developer so it takes a longer
time for your image to show up. I'm guessing that if you left it in
developer for a long time (several minutes) your image would eventually
appear.

hope that helps.
-Joe

yitianp@email.arizona.edu wrote:
> Thank you very much.
> I exposed at 8.8mw/cm2 about 10s
> What problem may be when the temperature is more than 100degree??
>
> Quoting Shay Kaplan :
>
>> Don't bake over 100 deg before exposure - 95 deg is better
>> Shay
>>
>> -----Original Message-----
>> From: mems-talk-bounces@memsnet.org
>> [mailto:mems-talk-bounces@memsnet.org]
>> On Behalf Of yitianp@email.arizona.edu
>> Sent: Tuesday, March 13, 2007 6:12 AM
>> To: mems-talk@memsnet.org
>> Subject: [mems-talk] hi for help about the develop
>>
>>  I spin S1813 at 4000rpm 45s.
>> Then hot bake 120Degree 10min
>> Exposure 10s, then develop 30s.After 30s, I can't see anything.
>> Why???
>> All paper recommend the develop time 30s.