Browse Prior Art Database

Coaxial Interconnections Using Advanced Metallurgy Technology

IP.com Disclosure Number: IPCOM000036235D
Original Publication Date: 1989-Sep-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 3 page(s) / 46K

Publishing Venue

IBM

Related People

Pearson, DJ: AUTHOR [+2]

Abstract

A technique is described whereby electro-migration failures of interlevel metal via interconnections is minimized through use of the Advanced METallurgy (AMET) technology. The technique is unique in that it produces coaxial interlevel metal vias, providing enhanced electro- migration resistance and connector redundancy in integrated circuit wiring.

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Coaxial Interconnections Using Advanced Metallurgy Technology

A technique is described whereby electro-migration failures of interlevel metal via interconnections is minimized through use of the Advanced METallurgy (AMET) technology. The technique is unique in that it produces coaxial interlevel metal vias, providing enhanced electro- migration resistance and connector redundancy in integrated circuit wiring.

In prior art, the use of Al/Cu as an interconnection metallurgy and its failure under electrical stress is well known. The AMET material minimizes the failures by making use of an Al/Cu-Hf-Al/Cu sandwich structure to provide enhanced electro-migration resistance and connector redundancy. This improved resistance and redundancy is due to the formation of an intermetallic Hf/Al compound. The concept applies the AMET techniques to coaxial vias.

A coaxial AMET via consists of two concentric cylindrical conductors, such as Al/Cu, sandwiching a layer of Al/Hf intermetallic material, as shown in Fig. 1. The Al/Hf intermetallic compound provides the electro-migration resistance, which, in turn, results in connector redundance. The relative thickness of the two conductor layers is chosen to provide equal cross-sectional areas between the two conductors.

The fabrication process of the coaxial via utilizes procedures already known and practiced in VLSI facilities. The process is applicable at any of the metallization layers and begins after the definition of the insulator via. The following six processing steps provide electro-migration resistance and connector redundancy over the entire vertical dimension. In addition, the via provides minimal cross- sectional exposure of the Al/Hf intermetallic of the via for optimal via...