Method for vapor phase etching of silicon

US7041224B2 · kind B2 · utility

Assignee

• Reflectivity, Inc. · US

Inventors

• Satyadev Patel · Palo Alto, US
• Gregory P. Schaadt · Santa Clara, US
• Douglas B. MacDonald · Caledonia, US
• Hongqin Shi · San Jose, US
• Andrew Huibers · Mountain View, US
• Peter Heureux · Felton, US

Key dates

• Filing date: Mar 22, 2002
• Grant date: May 9, 2006
• Expiry date: Mar 15, 2023

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B81C2201/0138
• WIPO field: Micro-structural and nano-technology
• WIPO sector: Chemistry

Abstract

The etching of a material in a vapor phase etchant is disclosed where a vapor phase etchant is provided to an etching chamber at a total gas pressure of 10 Torr or more, preferably 20 Torr or even 200 Torr or more. The vapor phase etchant can be gaseous acid etchant, a noble gas halide or an interhalogen. The sample/workpiece that is etched can be, for example, a semiconductor device or MEMS device, etc. The material that is etched/removed by the vapor phase etchant is preferably silicon and the vapor phase etchant is preferably provided along with one or more diluents. Another feature of the etching system includes the ability to accurately determine the end point of the etch step, such as by creating an impedance at the exit of the etching chamber (or downstream thereof) so that when the vapor phase etchant passes from the etching chamber, a gaseous product of the etching reaction is monitored, and the end point of the removal process can be determined. The vapor phase etching process can be flow through, a combination of flow through and pulse, or recirculated back to the etching chamber. A first plasma or wet chemical etch (or both) can be performed prior to the vapor phase etc…