Hi,

Apart from micromilling techniques, the best one will  be grayscale lithography.
Tilting the wafer could give you a sloped layer of PDMS, but if you use a binary
mask, might be you don´t get the sloped microchannel, at least in the way you
want.

Good luck



________________________________
Från: Tsoll Doiiu 
Till: [email protected]
Skickat: mån 28 februari 2011 3:43:55
Ämne: [mems-talk] Sloped microchannel

Hello MEMS community!

Does anybody have an idea how to prepare a sloped microchannel in PDMS?

Initially I've tried to do like this: spin-coat PR on Si wafer, than hold the
wafer vertically,

for like a 1h-4h, hoping  that gravity will make gradient in PR thickness, than
make UV.
Unfortunatelly, I did not achieve the slope. I used SU 25 for this.

Is there some other way to prepare oblique microchannel?
The desired sizes are: length - approx. 4cm, initial heigth 200um, final heigth
20um.

I want to make like this:
http://img193.imageshack.us/img193/5440/46006411.jpg

Also the ways to prepare slopes with angles 30-70 degrees are strongly wanted.

Thanks in advance!