Method of anisotropically etching silicon

US5501893A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Franz Laermer · Stuttgart, DE
• Andrea Schilp · Schwäbisch Gmünd, DE

Key dates

• Filing date: Aug 5, 1994
• Grant date: Mar 26, 1996
• Expiry date: Aug 5, 2014

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/24521
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

A method of anisotropic plasma etching of silicon to provide laterally defined recess structures therein through an etching mask employing a plasma, the method including anisotropic plasma etching in an etching step a surface of the silicon by contact with a reactive etching gas to removed material from the surface of the silicon and provide exposed surfaces; polymerizing in a polymerizing step at least one polymer former contained in the plasma onto the surface of the silicon during which the surfaces that were exposed in a preceding etching step are covered by a polymer layer thereby forming a temporary etching stop; and alternatingly repeating the etching step and the polymerizing step. The method provides a high mask selectivity simultaneous with a very high anisotropy of the etched structures.