Hi,
I have deposited 4 layers of SU-8 2002 on conductors of Gold-Titanium.  Each
layer was spin coated at 3000rpm to obtain a nominal thickness of 2um.  So I
should get a film of about 8um.  After exposure at 140mJ/cm2 and post-exposre
bakinbg at the recommended temperature of 95'C for 4mins, I observed that there
were always hairlines on the crosslinked SU-8.  Are these micro-cracks?  How do
I get rid of them?

Is it safe to spin coat another layer of SU-8 2150 on this layer to build a
multiple layer SU-8 film and develop without the whole film cracking or
delaminating?

Jeffrey