Sandip Agarwal wrote: > 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. > Hmmm comets. I guess you are trying to planarise the substrate so you are looking for ~10um of polymer? have you thought about doing it it in 2 spins? with a softbake?