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Method for Metallization Patterning

IP.com Disclosure Number: IPCOM000112510D
Original Publication Date: 1994-May-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 62K

Publishing Venue

IBM

Related People

Kitahara, H: AUTHOR [+2]

Abstract

Disclosed is a device and method for patterning aluminum film over tantalum-alloy film as expected. By exposing tantalum alloy in the oxygen, nitrogen or oxygen plasma atmosphere, tantalum-oxide or tantalum-nitride layer is made on the tantalum-alloy layer. Oxide or nitride layer prohibits tantalum to diffuse in the aluminium layer and also prohibits aluminum to diffuse in the tantalum-alloy layer, so no tantalum-aluminum alloy is made. As there is no tantalum-aluminum alloy that prevent aluminum from dissolving in the etchant, aluminum patterning without residue is available.

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Method for Metallization Patterning

      Disclosed is a device and method for patterning aluminum film
over tantalum-alloy film as expected.  By exposing tantalum alloy in
the oxygen, nitrogen or oxygen plasma atmosphere, tantalum-oxide or
tantalum-nitride layer is made on the tantalum-alloy layer.  Oxide or
nitride layer prohibits tantalum to diffuse in the aluminium layer
and also prohibits aluminum to diffuse in the tantalum-alloy layer,
so no tantalum-aluminum alloy is made.  As there is no
tantalum-aluminum alloy that prevent aluminum from dissolving in the
etchant, aluminum patterning without residue is available.

      Though aluminum is useful as material of wiring of transistor,
as the adhesion is relatively weak, aluminum wiring often swell or
have crack after heating processes to cause intrusion of etchant in
the defect.  In general, the adhesion of metal is improved by making
another film under it that is harder and have good adhesion.
Tantalum alloy is good for this purpose, but tantalum alloy makes
tantalum-aluminum alloy between tantalum and aluminum by diffusing to
each other's layer.  As tantalum-aluminum alloy does not dissolve in
aluminum etchant like the mixture of phosphoric acid, acetic acid,
nitric acid, and water, residue of tantalum-aluminum alloy remains
after aluminum etching.

      By making tantalum-oxide or tantalum-nitride layer between
tantalum alloy and aluminum, the diffusion is obstructed and to make
no tantalum-aluminu...