Mario,
I assume that your prebake temperatures are missing a decimal point and they
should be 50.0C and 90.0C.  Assuming you can measure the light intensity at 405
nm the exposure should be about 50 mj/sq.cm per micron of resist, thus if you
have 100 microns at an intensity of 23 mw/sq.cm (assuming 405 nm) the correct
exposure would be  (50 x100) / 23 equals about a 200 second exposure (I'm
assuming here that the light intesity was measured at 405 nm).

The pre bakes look fine, maybe a little long.  The post exposure bake should be
lower, near 65.0C, for about 90 to 180 seconds.

The develop should be a two stage develop, first bath about 3/4 of the time
required and second bath to rinse about 1/4 the total time required.

I've used this for 20 to 100 u films with good results.

Clif

Clif

>>> Mario Adamschik  08/31 3:02 AM >>>
Question for Discussion group:

Subject: SU-8 50 Patterning

I recently bought SU-8 50 resist and I tried to
pattern the resist with the following parameter:

Sample: Si wafer, about 2cm x 2cm

Dehydration Bake 1h, 2300C

Spinning: 700rpm 5s
          2000rmp 35s

10min sheet relaxation

pre bake 2min 500C  Hotplate
         30min 900C Hotplate

Exposure: 9, 12, 15, 17, 19s (5 samples), 23mW/cm^2

post-bake 500C 2min
          950C 5min slow cool down (2h)

developing: 10min

After developing the resolution was bad and there
were a lot of rifts on the resist surface. Can anyone help me with
optimized parameters to achieve sheet thicknesses of
approx. 100um and 50...60um with SU-8 50 ?!

Thank anyone very much in advance.

Mario