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Method of Eliminating Aluminum Chloride Formation in an Aluminum Plasma Etcher

IP.com Disclosure Number: IPCOM000050111D
Original Publication Date: 1982-Sep-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Bondur, JA: AUTHOR [+4]

Abstract

The use of TEFLON* tape on the aluminum cathode of a reactive ion etching chamber eliminates unwanted formation of aluminum chloride on the etch sample anode.

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Method of Eliminating Aluminum Chloride Formation in an Aluminum Plasma Etcher

The use of TEFLON* tape on the aluminum cathode of a reactive ion etching chamber eliminates unwanted formation of aluminum chloride on the etch sample anode.

Chlorine based gases can be used to etch silicon in plasma reactors with electrodes constructed of aluminum material. The process capability is limited by the naturally formed aluminum oxide barrier that prevents a chemical reaction between the chlorine and the aluminum. If etch times become excessive, the aluminum oxide breaks down and aluminum chloride compounds are formed. This material deposits on the etch sample surfaces, causing a non uniform etch. In addition, this aluminum chloride material is hydroscopic and causes long pump down cycles with the etcher.

When TEFLON material is used to coat the internal surfaces of the plasma etch reactor, the material protects the metal surfaces from the chemical reaction with the plasma. Chlorine containing gases can be used to etch silicon without the aluminum chloride compound formation. Thus, system pump down times are short, and etch depths are uniform.

Deep vertical grooves can be etched into silicon by this technique using organic photoresist as an etch mask with good etch uniformity. * Trademark of
E. I. du Pont de Nemours & Co.

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