Method for etching tungsten

US4849067A · kind A · utility

Assignee

• TEXAS INSTRUMENTS INCORPORATED · US

Inventors

• Rhett B. Jucha · Celeste, US
• Cecil J. Davis · Greenville, US
• Duane E. Carter · Plano, US
• Sue Crank · Coppell, US
• John I. Jones · Plano, US

Key dates

• Filing date: Jul 16, 1987
• Grant date: Jul 18, 1989
• Expiry date: Jul 16, 2007

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L21/32136
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

A fluorine based metal etch chemistry, wherein an admixture of etch products (or species which are closely related to etch products) is added during the post etch stage, i.e. during the stage when the pattern has partially cleared by overetch is not yet completed, to maintain the balance of chemistries which provides selectivity and anisotropy. In a tungsten etch, WF.sub.6 is usefully added during the post etch period to provide this loading.