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Etching Process for Tantalum Gold Composite Metallurgy

IP.com Disclosure Number: IPCOM000087517D
Original Publication Date: 1977-Feb-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Metzger, WC: AUTHOR [+3]

Abstract

A composite tantalum/gold/tantalum metallurgy is attractive as an inter connection metallurgy system for semiconductor materials because it has high conductivity, excellent electromigration resistance and good corrosion resistance. However, a significant problem exists in the formation of the microminiature patterns on the film composite due to the limitations of the subtractive chemical etching processes, unfavorable etch rate versus power input for RF sputter-etching, and temperature limitations of lift-off processes.

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Etching Process for Tantalum Gold Composite Metallurgy

A composite tantalum/gold/tantalum metallurgy is attractive as an inter connection metallurgy system for semiconductor materials because it has high conductivity, excellent electromigration resistance and good corrosion resistance. However, a significant problem exists in the formation of the microminiature patterns on the film composite due to the limitations of the subtractive chemical etching processes, unfavorable etch rate versus power input for RF sputter- etching, and temperature limitations of lift-off processes.

In this process, the tantalum/gold/tantalum metallurgy interconnection pattern is fabricated by depositing the composite blanket layers on a substrate, masking the metallurgy layer with a resist or other suitable masking layer utilizing conventional photolithographic techniques, and reactively ion etching the masked substrate in an atmosphere which includes a reactive gas such as CCl(4), Cl(2), Br(2), HCl, HBr, or CBr(4). Under these sputter-etching conditions, the chlorine or bromine ionic species form volatile compounds with the gold and tantalum.

Preferably, the atmosphere is a mixture of CCl(4) in argon with a total pressure of approximately 10 to 20 microns.

In applications where selective etching of tantalum is desired, the sputtering atmosphere can contain only CF(4), with or without argon. Under these conditions the fluorine ionic species forms volatile compounds with tantalum but not...