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1. (WO2018044727) METHOD OF ANISOTROPIC EXTRACTION OF SILICON NITRIDE MANDREL FOR FABRICATION OF SELF-ALIGNED BLOCK STRUCTURES

Pub. No.:    WO/2018/044727    International Application No.:    PCT/US2017/048689
Publication Date: Fri Mar 09 00:59:59 CET 2018 International Filing Date: Sat Aug 26 01:59:59 CEST 2017
IPC: H01L 21/3065
H01L 21/3213
H01L 21/311
Applicants: TOKYO ELECTRON LIMITED
TOKYO ELECTRON U.S. HOLDINGS, INC.
Inventors: SHERPA, Sonam D.
RANJAN, Alok
Title: METHOD OF ANISOTROPIC EXTRACTION OF SILICON NITRIDE MANDREL FOR FABRICATION OF SELF-ALIGNED BLOCK STRUCTURES
Abstract:
A method of preparing a self-aligned block (SAB) structure is described. The method includes providing a substrate having raised features defined by a first material containing silicon nitride and a second material containing silicon oxide formed on side walls of the first material, and a third material containing an organic material covering some of the raised features and exposing some raised features according to a block pattern formed in the third material. The method further includes forming a first chemical mixture by plasma-excitation of a first process gas, and exposing the first material on the substrate to the first chemical mixture. Thereafter, the method includes forming a second chemical mixture by plasma-excitation of a second process gas, and exposing the first material on the substrate to the second plasma-excited process gas to selectively etch the first material relative to the second and third material.