Funny you mentioned it.
Recently these " mousebites started appearing in our lithography too.
I have a suspicion,I hope to test the hypothesis one of these days:
I think we are getting little droplets of water in our Nitrogen line.
Since we often blow dry the samples with N2, even AFTER priming, these droplets
may be giving origin to
poor adhesion in localized spots.

Simple tests: 1) Blow dry sample and check under microscope, and look for
droplets.
        2) Skip any blow drying, use only spin dry, and se if that gets rid of
mousebites.

Jose Rberto Senna
LAS-INPE
CP 515
12201-970 Sao Jose dos Campos SP
BRAZIL