Thorsten,

  The key to Su8 bonding is in the pre-bake.  Try reducing the time for the soft
bake, this is dependant on Temp.  I would try a pre-bake of 65C for 1min,
followed by a ramp upto 95C for another minute or two (See MicroChem's website
for pre-bake details).  Then bonding should be done between 150C and 200C.  If
you want some more help feel free to contact me directly.

Best Regards,

Brian Douglas
Suss Microtec Inc.
Applications Engineer - Bonders
Phone: (802) 244 - 5181 x202
Fax:  (802) 244 - 5103