Hello,

I am wondering if PDMS can be spin-casted on the silicon wafer. There is
very limited literature talking about coating the sub-micron-thick PDMS
thin-film.

I have tried to dilute PDMS (Dow Corning Sylgard 184 PDMS 10:1 mixture) with
toluene in ratio of 10:1 to 20:1. The spin speed is controlled from 1000 rpm
to 3000 rpm in 40 seconds. However, the film uniformity is pretty bad. I can
even observe the uncovered region by naked eyes, especially in higher
spinning speed. I believe the bad uniformity maybe come from the high
evaporation rate of toluene, but have no idea about better candidate to
substitute it.

That will be very helpful if someone can share the experience on PDMS
spin-casting.

Thank you,

Yun-Ching