Are you trying to etch polymer to make waveguide? If yes, you can try low
pressure/high power process to get vertical wall. But this process also
increases the sidewall roughness. So you have to compromise between your etched
wall angle and side wall roughness. You can mix O2 into your SF6 + C4F8
chemistry.

Good luck.

With regards,

Pramod Gupta
21084 Red Fir Court
Cupertino, CA 95014
Phone: (408) 253-1646

--- On Wed, 7/21/10, 杜 彦召  wrote:


From: 杜 彦召 
Subject: [mems-talk] rib waveguide using dry etch
To: [email protected]
Date: Wednesday, July 21, 2010, 5:07 PM


Hi all,

I am making rib waveguide using a dry etch method.  I have two problems:

(1) How to get vertical sidewall, SF6 + C4F8 process
(2) How to minimize the sidewall roughness


杜彦召