You can try to reduce the CHF3/CF4 ratio if you haven't done this already.
This should decrease the polymer deposition on the sidewalls.

Regards

Simone Capecchi

Simone Capecchi
Optical Engineer
Terahertz Photonics Limited
Rosebank park
Livingston
EH54 7EJ
Tel :- 01506-818534
Fax :- 01506-818577

 -----Original Message-----
From:   Carl Arft [mailto:[email protected]]
Sent:   02 January 2003 22:56
To:     [email protected]
Subject:        [mems-talk] Contamination problems when etching silicon
oxynitride

Hello

I am currently using PECVD silicon oxynitride to fabricate optical
waveguides.  However, I am running into a contamination problem when
etching the waveguides.  I am using chromium as an etch mask, and
perfoming the RIE using CF4 and CHF3 in Helium.  The black/grey
contamination appears around the chromium lines, and EDS has shown it to
be mainly carbon-based.

Has anyone else run into a similar problem, or knows how to solve this
problem?  Any help is appreciated!  Please send responses to:
[email protected]


********************************************
Carl Arft
Dept. of Electrical and Computer Engineering
University of California, Davis
Phone: (530) 754-9249
Email: [email protected]
********************************************


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