Hi,

   I am interested in knowing how you deposit teflon on the sides of cavity.

Richard

----- Original Message -----
From: "Yuchin" 
To: "General MEMS discussion" 
Sent: Monday, March 20, 2006 5:37 PM
Subject: [mems-talk] teflon deposit problem


> Hello all,
>
> the figure:  http://yuchin.kao.googlepages.com/02.jpg
> Purple: teflon  black: Si   Blue: Si3N4    Red: metal
>
> 1. Deposit Si3N4 layer (3000A) on the double side of the wafer.
> 2. Photolithography process to pattern the cavity and etch through the
> wafer(as the fighre)
>    the width of the cavity is about 1.5mm and the depth is 400um(etch
> through the wafer)
> 3. Deposit teflon on the topside(the thickness have not been designed.)
> 4. Remove teflon on Si3N4
> 5. Remove Si3N4 in the cavity to make the metal layer suspended (the metal
> layer will be the bottom of the cavity )
>    There are no teflon on the bottom of the cavity(metal layer)
>
> Step 4 is a big problem for me. The cavity is too deep to coat PR. So I
> can't use lift-off and photolithography process to pattern teflon.
> If the adhesion between teflon and Si3N4 is weak,  maybe I can use
> supersonic clean to lift off the teflon on Si3N4
>
> Is there any method to solve this problem?
>