Contactless real-time in-situ monitoring of a chemical etching

US5516399A · kind A · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Michael J. Balconi-Lamica · Poughquag, US
• Steven G. Barbee · Beekman, US
• Tony F. Heinz · Chappaqua, US
• Yiping Hsiao · San Jose, US
• Leping Li · Poughkeepsie, US
• Eugene H. Ratzlaff · Hopewell Junction, US
• Justin W. Wong · South Burlington, US

Key dates

• Filing date: Jun 30, 1994
• Grant date: May 14, 1996
• Expiry date: Jun 30, 2014

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L2924/0002
• WIPO field: Machine tools
• WIPO sector: Mechanical engineering

Abstract

A contactless method and apparatus for real-time in-situ monitoring of a chemical etching process for the etching of at least one wafer in a wet chemical etchant bath are disclosed. The method comprises the steps of providing at least two conductive electrodes in the wet chemical bath, wherein the at least two electrodes are proximate to but not in contact with the at least one wafer, and further wherein said two electrodes are positioned on the same side of the wafer; and monitoring an electrical characteristic between the at least two electrodes, wherein a prescribed change in the electrical characteristic is indicative of a prescribed condition of the etching process. Such a method and apparatus are particularly useful in a wet chemical etch station.