US 6,661,097 B1Granted

Ti liner for copper interconnect with low-k dielectric

AssigneeInternational Business Machines Corporation

InventorsLarry Clevenger, Stanley J. Klepeis, Hsiao-Ling Lu, Jeffrey R. Marino, Andrew Herbert Simon, Yun-Yu Wang, Kwong Hon Wong, Chih-Chao Yang

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Abstract

In copper backend integrated circuit technology, advanced technology using low-k organic-based interlayer dielectrics have a problem of carbon contamination that dos not occur in circuits using oxide as dielectric. A composite liner layer for the copper lines uses Ti as the bottom layer, which has the property of gettering carbon and other contaminants. The known problem with Ti of reacting with copper to form a high resistivity compound is avoided by adding a layer of TiN, which isolates the Ti and the copper.

Claims20

Dependent claims

A method of forming an electrical interconnect structure comprising the steps of:

providing a set of refractory material contacts embedded in a first interlevel dielectric;
providing a second interlevel dielectric containing carbon disposed above said first interlevel dielectric;
forming a set of openings in said second interlevel dielectric, at least some of which expose top surfaces of some of said contacts, whereby a contaminant from the group comprising carbon, oxygen and nitrogen deposits on said top surfaces;
depositing a first liner layer of Ti in said set of openings, whereby said Ti getters said contaminant;
depositing a second liner layer above said first liner layer;
and depositing copper above said second liner layer in said openings to form a layer of interconnect.

3 more elements

Dependencies are inferred from the claim text.