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Preferential Control of Si(3)N(4) Sidewalls

IP.com Disclosure Number: IPCOM000049703D
Original Publication Date: 1982-Jul-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Gajda, JJ: AUTHOR [+3]

Abstract

This is a proposal for an improved control of silicon nitride sidewalls in contact areas to reduce a potential aluminum penetration through a chrome barrier. A glycerated Buffered HF solution is used as etchant, which is described in U.S. Patent 4,230,523, for the removal of silicon dioxide films.

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Preferential Control of Si(3)N(4) Sidewalls

This is a proposal for an improved control of silicon nitride sidewalls in contact areas to reduce a potential aluminum penetration through a chrome barrier. A glycerated Buffered HF solution is used as etchant, which is described in U.S. Patent 4,230,523, for the removal of silicon dioxide films.

Conventional processes to define Si(3)N(4) windows result in feathered Si(3)N(4) sidewalls which may not be sealed by a subsequently applied Cr layer in the course of forming the contact metallurgy. The Cr is rather discontinuous over the feathered edge, thus destroying the contact by Al-Cu penetration to the PtSi and the silicon substrate.

A conventional process uses a 10:1 Buffered HF solution to clean contacts from RIE (reactive ion etching) residue and to remove the PtSi passivation layer prior to Cr and Al-Cu evaporation. According to this proposal, a solution of glycerine HF NH(4)F with a 2:1:5 proportion is substituted for the 10:1 Buffered HF. The glycerine-based solution removes all RIE residue and also the PtSi passivation layer. The added feature of the glycerine-based solution is the preferential removal of the lower feathered edge of Si(3)N(4) and the elimination of the ragged Si(3)N(4) edges.

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