Hi there,

I have not tried this suggestion. However, it would seem to me that if you
mounted the substrate at an angle to the axis of rotation of the spinner (rather
than it being perpendicular), you might be able to achieve the difference in
height of the photoresist. Now it would be up to you to try and achieve that in
your spinner...

Good luck,
Dietrich

-----Original Message-----
From: Tsoll Doiiu [mailto:tsoll_doiiu@mail.ru]
Sent: 28 February 2011 02:44
To: mems-talk@memsnet.org
Subject: [mems-talk] Sloped microchannel[Scanned]

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!