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1. (WO2017151958) ISOTROPIC SILICON AND SILICON-GERMANIUM ETCHING WITH TUNABLE SELECTIVITY

Pub. No.:    WO/2017/151958    International Application No.:    PCT/US2017/020503
Publication Date: Sat Sep 09 01:59:59 CEST 2017 International Filing Date: Fri Mar 03 00:59:59 CET 2017
IPC: H01L 21/306
H01L 21/02
H01L 21/205
Applicants: TOKYO ELECTRON LIMITED
TOKYO ELECTRON U.S. HOLDINGS, INC.
Inventors: KAL, Subhadeep
KANDABARA N., Tapily
MOSDEN, Aelan
Title: ISOTROPIC SILICON AND SILICON-GERMANIUM ETCHING WITH TUNABLE SELECTIVITY
Abstract:
Isotropic silicon and silicon-germanium etching with tunable selectivity is described. The method includes receiving a substrate having a layer of silicon and a layer of silicon-germanium with sidewall surfaces of silicon and silicon-germanium being uncovered, positioning the substrate in a processing chamber configured for etching substrates, and modifying uncovered surfaces of silicon and silicon-germanium by exposing the uncovered surfaces of silicon and silicon-germanium to radical species. The method further includes executing a gaseous chemical oxide removal process that includes flowing a mixture of a nitrogen-containing gas and a fluorine-containing gas at a first substrate temperature to form a fluorine byproduct followed by executing a sublimation process to remove the fluorine byproduct at a second substrate temperature that is higher than the first substrate temperature, and controlling the second substrate temperature to tune the sublimation rate and etch selectivity of a silicon oxide material relative to a silicon-germanium oxide material.