I am trying to spin-coat a polymer (1% PMMA-butadiene copolymer in
toluene) on a substrate that has topographical features that are 50x50
micron posts and 10 microns tall. I observe striations or ripples that
run from the center of the substrate to the periphery after
spin-coating. Any solutions? I have tried varying the concentration and
dynamic dispensing without any success.