Hi Yong,

I have managed to spin coat after release with very little damage to the
structures on the die. The
sample I was using was a 1 square centimeter die from the MUMPS process, and
included 4-micron-wide
wandering-beam tethers that might have a similar structure to the digits on your
comb drive. I ran
the spinner at 4000 RPM with Shipley 1813 photoresist. I repeated this with
multiple dice, and even
up to three times on the same die with only very slight damage.

I have found MEMS structures from the MUMPS process to be remarkably resilient.
I once accidentally
dropped a die butter-side-down in the spinner bowl, and was still able to
continue experimenting on
the chip!

You may find that you have trouble with stiction following the photolithography.
To resolve this
problem, I emmersed the chip in water after pattern transfer was complete, and
then performed a CO2
critical-point dry. This worked rather well for me.

Best of luck with your research!

-Craig McGray
 Dartmouth College



> From: "Yong Zhu" 
> To: 
> Date: Thu, 27 Sep 2001 01:22:48 -0500
> Subject: [mems-talk] spin photoresist after releasing the structure
>
> Hello, MEMS friends;
>
> Does anyone have experience to spin photoresist after releasing the structure,
such as comb drive?
>
> I am wondering if the spin will damage the suspended device. I would like to
get some idea before
> I make the design. Thank you.
>
> Yong