Dear all,

I have published a curve regarding to PDMS layer thickness with spin speed and
spin time. The following is the paper.

In the same paper, I also discussed the measurement methods to obtained the
thickness of PDMS film. For my experience, the results obtained using
ellipsometry is WRONG. I believe the film is too thick to measure using using
ellipsometer.

Spin-coating is not a good way to handle Sylgard 184 due to curing mechanism.
Sylgard 184 is 2 parts products. When you mix them together,
the curing agent (Pt particles) will distributed randomly. When you film
thick is smaller than the particle diameters (~10um-20um), you can observed
this very clearly. I do recommend using the SPIN-ON silicone (WL-5000,
Dow corning) if you want to have a uniform thin film.

W.Y. Zhang, G. S. Ferguson, S. Tatic-Lucic; "ELASTOMER-SUPPORTED COLD WELDING
FOR ROOM TEMPERATURE WAFER-LEVEL BONDING", Technical Digest of 17th IEEE Intl.
Conference on Micro Electro Mechanical Systems (MEMS 2004), The Netherlands,
January 2004. pp. 741-4.

http://www.lehigh.edu/~wez6/MEMS2004_ESCW_Lehigh.pdf

Good luck,

Lydia