Hi,

Su-8 adhesion is highly dependent on the chemical environment of the
resist. A lot of tips (about adhesion and other issues) can be found
on memscyclopedia (http://memscyclopedia.org/su8.html).

However, i recommend you to start incrementing the dose of UV
exposure. As su-8 is a negative epoxy-based resist, the curing process
is from top to bottom, resulting in poor adhesion if you no expose the
resist above the critical dose for this thickness.

Best regards,

Karim

On Tue, Apr 5, 2011 at 12:10 AM, 첸로  wrote:
> Dear all,
>
> I am using su-8 in photolithography technique. I'm having difficulty when
handling it.
>
> The adhesion strength of su-8 and silicon is not very even.  I clean the
silicon wafer in piranha solution, give it a oxygen plasma treatment and use the
Mcc primer (microchem).
> After 1.5 minutes developing some patterns will peel off.   M mask dimension
is only 10microns.
>
> Has anybody encountered this problem?
>
> Is the adhesion strength decided by the softbake time or post bake time or
both?
> Should I increase the baking time for both?
>
> Any suggestions will be highly appreciated.
>
> Thanks a lot in advance.