The etching of the waveguide has to be anisotropic, and increasing the SF6 will
give you more isotropic etching. Therefore, having vertical wall with less
sidewall roughness and higher etch rate is tricky. There has to be a balance
between SF6, CH4F8 and O2 flow.


--- On Sun, 9/26/10, Jie Zou  wrote:

From: Jie Zou 
Subject: Re: [mems-talk] Dry Etch - Room T continuous process
To: "General MEMS discussion" 
Date: Sunday, September 26, 2010, 1:05 PM

Increase SF6, decrease C4F8. Or increase power. This would make the
etching more isotropic, undirectional.

On Sun, Sep 26, 2010 at 12:12 AM, 杜 彦召  wrote:
> Hi all;
>
> Now i am making silicon rib waveguide using dry etcing . To decrease the
sidewall roughness as much as possible i plan to use Room T continuous process
instead of Bosch process. Anybody can give some suggstion to increase the etch
rate ?
>
> My  process parameter:SF6:C4F8:O2
>
> sccm:5sccm:80sccm,power=800w,time=120s,pressure=10mT,RF power=10w
>
>
> Andrew