Hi, everybody
I tried to coat a 20um su8 mask on glass. Su8-50 is used in this process. After
developing, cracks are observed everywhere on su8. These cracks are run through
the entire su8 layer. It is really wired since I used the same protocol and get
succeed last year.

Here is the procedure I’ve followed:
Plasma cleaning―bakes 20mins @ 200c
Spin coating
Soft bake 3mins @65c, 15mins @95c, cool down to RT in 45mins
Expose 250mj/cm2
Post expose bake 1mins @65c, 4mins @95c, cool down to RT in 45mins
Develop

Also I noticed that the su8 which I used was expired last July. Is the
expiration the explanation for cracking? Or the incorrect exposure dose? Or
something else?

Thanks

--sonic