Browse Prior Art Database

Buffered HF Etch Barrier

IP.com Disclosure Number: IPCOM000050838D
Original Publication Date: 1982-Dec-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Flachbart, RH: AUTHOR [+2]

Abstract

In an existing process for via etching it is the functional metallurgy itself that is relied upon to prevent the BHF (buffered hydrofluoric acid) etchant from attacking the material beneath the functional metallurgy. The etchant could, due to the over-etch employed in most processes, travel along grain boundaries or through discontinuities in the film and attack the underlying material, thereby causing either time zero fails or reliability fails in the field.

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Buffered HF Etch Barrier

In an existing process for via etching it is the functional metallurgy itself that is relied upon to prevent the BHF (buffered hydrofluoric acid) etchant from attacking the material beneath the functional metallurgy. The etchant could, due to the over-etch employed in most processes, travel along grain boundaries or through discontinuities in the film and attack the underlying material, thereby causing either time zero fails or reliability fails in the field.

A scheme to prevent this from happening is to deposit a barrier film, e.g., approximately 1000 Angstroms chrome or any other such film, on top of the functional film which is not attacked by BHF, thereby preventing further etching. This film could be subsequently removed chemically or reactively in situ after via etch and prior to the next level of metal deposition. This scheme is applicable in all single and multi-level wiring products where the underlying material requires etch protection from BHF.

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