Both AZ9260 and AZ9620 (which one is it?) are very thick resists. I suspect that
you are having difficulty from a positive slope in your PR. The ways to remedy
this include: image reversal (new mask), surface treatment before developing (I
forget the name
of the most commnly used chemical), and switching to a thinner resist (less
space between the mask and the bottom of the PR).

As for the "grainy metal surface," you got me there. Is your mask of
professional quality, did it come from a mask maker, and not, say, a printer?

Jesse Fowler