Selectively etching metals and metal nitrides conformally

US9449843B1 · kind B1 · utility

Assignee

• Applied Materials, Inc. · US

Inventors

• Mikhail Korolik · San Jose, US
• Nitin K. Ingle · San Jose, US
• David Thompson · San Jose, US
• Jeffrey W. Anthis · San Jose, US
• David Knapp · Mineral Point, US
• Benjamin Schmiege · Santa Clara, US

Key dates

• Filing date: Jun 9, 2015
• Grant date: Sep 20, 2016
• Expiry date: Jun 9, 2035

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C23F1/12
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

Methods of selectively etching metals and metal nitrides from the surface of a substrate are described. The etch selectively removes metals and metal nitrides relative to silicon-containing layers such as silicon, polysilicon, silicon oxide, silicon germanium, silicon carbide, silicon carbon nitride and/or silicon nitride. The etch removes material in a conformal manner by including an oxidation operation which creates a thin uniform metal oxide. The thin uniform metal oxide is then removed by exposing the metal oxide to a metal-halogen precursor in a substrate processing region. The metal oxide may be removed to completion and the etch may stop once the uniform metal oxide layer is removed. Etches described herein may be used to uniformly trim back material on high aspect ratio features which ordinarily show higher etch rates near the opening of a gap compared to deep within the gap.