Browse Prior Art Database

Thin Film Structure

IP.com Disclosure Number: IPCOM000040845D
Original Publication Date: 1987-Feb-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Protschka, H: AUTHOR

Abstract

An existing film for FET-metallization uses a composite of aluminum-copper layer 1 and polysilicon layer 2 as shown in Fig. 1. A positive resist on top of the polysilicon layer 2 must be developed with a base type of developer (KOH) after photo exposure Voids in the polycrystalline silicon layer 2 cause interaction with the corrosion-sensitive aluminum-copper layer 1 resulting in corrosion problems which produce a metal residue in etched metal spaces. When higher copper concentrations are used to guard against electromigration, the problem is increased.

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Thin Film Structure

An existing film for FET-metallization uses a composite of aluminum-copper layer 1 and polysilicon layer 2 as shown in Fig. 1. A positive resist on top of the polysilicon layer 2 must be developed with a base type of developer (KOH) after photo exposure Voids in the polycrystalline silicon layer 2 cause interaction with the corrosion-sensitive aluminum-copper layer 1 resulting in corrosion problems which produce a metal residue in etched metal spaces. When higher copper concentrations are used to guard against electromigration, the problem is increased.

By introducing an intermediate layer 3 of aluminum between layers 1 and 2, the sensitive aluminum-copper alloy film 1 is protected from attack during resist development and the metallic residue in the metal spaces is eliminated.

Disclosed anonymously

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