Re: Selective dry etching of SiN from silicon

Donguk,

In a CHF3/O2 process if you up the O2 percentage you will increase your sel of nitride to oxide (See Stocker paper for work done on AMT type etcher). By using N2 instead of O2, you can get high sel of nitr to poly-Si at high percentages of N2 (See Li paper for work done in (MRC/Drytek4)RIE type tool. You can also get high sel to Si using CF4 or NF3 in high percentages of O2 (See Kastenmeier paper fpr work done in a downstream uwave etcher. The Gasonic is the closest tool like this which have but it dose not have Cf4 or NF3.).

Jim

Stocker, H.J. et al. "Selective reactive ion etching of silicon nitride on
oxide in a multifacet ('HEX') plasma etching machine" 35th National
Symposium of the American Vacuum Society. Held: Atlanta, GA, USA 2-7
Oct. 1988. J. Vac. Sci. Technol. A, Vac. Surf. Films (USA), Journal of
Vacuum Science & Technology A (Vacuum, Surfaces, and Films) (May-June
1989) vol.7, no.3, pt.1 p. 1145-9

Li, Y.X. et al. "Selective reactive ion etching of silicon nitride over
silicon using CHF/sub 3/ with N/sub 2/ addition" JOURNAL OF VACUUM
SCIENCE & TECHNOLOGY B (MICROELECTRONICS AND NANOMETER STRUCTURES)
Sept.-Oct. 1995. vol.13, no.5, p. 2008-12

Kastenmeier, B.E.E. et al. "Highly selective etching of silicon nitride
over silicon and silicon dioxide" JOURNAL OF VACUUM SCIENCE & TECHNOLOGY
A (VACUUM, SURFACES, AND FILMS) AIP for American Vacuum Soc, Nov. 1999.
vol.17, no.6, p. 3179-84

----- Original Message -----
From: "Donguk Nam" <dwnam83@gmail.com>
To: labmembers@snf.stanford.edu
Sent: Monday, June 11, 2012 11:07:53 PM
Subject: Selective dry etching of SiN from silicon

Dear Labmembers,

Does anyone have any experience in selective dry etching of SiN from silicon? I have been using CHF3/O2 in Drytek4 but the etch selectivity is not high enough for my process.

Please let me know if anyone has some experience.

Best regards,
Donguk