[mems-talk] Striations during spin-coating

[Matthew Walker]

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?