Methods for plasma etching of silicon

US7166536B1 · kind B1 · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Franz Laermer · Stuttgart, DE
• Andrea Schilp · Schwäbisch Gmünd, DE
• Bernhard Elsner · Bad Berka, DE

Key dates

• Filing date: Mar 16, 2000
• Grant date: Jan 23, 2007
• Expiry date: Mar 16, 2020

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02P70/50
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

A method of plasma etching, in particular of anisotropic plasma etching, of laterally defined structures in a silicon substrate, using a process gas, includes having at least one passivating material precipitated on the side walls of the laterally defined structures at least from time to time prior to and/or during etching. In an exemplary method, at least one of the compounds selected from the group ClF3, BrF3, or IF5 is added to the process gas as a fluorine-delivering etching gas. In another exemplary method, NF3 is added to the process gas, at least from time to time, as an additive consuming the passivating material. Finally, in another exemplary method, a light and easily ionizable gas, in particular H2, He, or Ne, is added, at least from time to time, to the process gas. The three exemplary methods may be combined.