Hey Mike,

That sounds a nice idea! I have a question though. Do you heat the wafer
gradually from room temperature to 65C or you just heat it directly at 65C
after spincoating? The same question can also be applied to the 65C to 95C
situation.

Our hotplate heats up very quickly, I have to do ramped heating manually.
This give me a hard time. What kind of hotplate are you using?

I also read that covering a Petri dish on the wafer during softbaking may
also helpful, as this prevent the surface from drying too quickly.

Looking forward to hearing from you!

Peng Li

> Hi Peng,
>
> Yes, ramped heating will help you avoid wrinkling and cracking of the
> SU8 surface.  I usually have two hotplates set to 65C and 95C -- I
> first place my wafers on the 65C plate, then to 95C and finally back to
> 65C.
>
> Another thing I do to avoid wrinkled surface is to let the SU8 just sit
> at room temperature for 10 minutes right after I spin it on.  I found
> that the SU8 will "smooth out" quite a bit during these 10 minutes.
>
> Good luck,
>
> Mike
>