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Proceedings Paper

Studies of low-pressure helical resonator discharges for advanced etching
Author(s): Dale E. Ibbotson; Chorng Ping Chang
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Paper Abstract

We have performed diagnostic measurements and polysilicon etching experiments using a halfwave radio frequency helical resonator (HR) source with a 150 mm ? discharge to develop and characterize this technology for low-pressure, high density plasma processing. This discharge source was applied to submicron, anisotropic etching of polysilicon gates using Cl2 and Cl2 /HBr at low pressure (~ 10-3 torr). A solenoidal magnetic field ~60 G along the discharge tube axis enhances plasma density between the source and wafer by a factor of 3–4 to > 1011 cm-3 in a 1000W discharge. In a Cl2/20% HBr feed gas mixture we obtain >3000 Å/min for undoped polysilicon, vertical profiles, and no proximity effects using -10 Vdc additional bias imposed on the wafer. Selectivities for polysilicon over gate oxide and trilevel resist were 50:1 and 4:1, respectively, with no bias during the overetching step.

Paper Details

Date Published: 1 February 1992
PDF: 7 pages
Proc. SPIE 1593, Dry Etch Technology, (1 February 1992); doi: 10.1117/12.56929
Show Author Affiliations
Dale E. Ibbotson, AT&T Bell Labs. (United States)
Chorng Ping Chang, AT&T Bell Labs. (United States)

Published in SPIE Proceedings Vol. 1593:
Dry Etch Technology
Deepak Ranadive, Editor(s)

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