Deposition of barrier layer and CVD copper under no exposed wafer conditions: adhesion performance and process integration

Abstract

Describes the development of an integrated in-situ process for the sequential deposition of the barrier layer (Ti/TiN or Ta/TaN), and the CVD Cu layer under no-exposed-wafer (cluster tool) conditions. Results of a systematic and quantitative study of the adhesion strength of Cu CVD on various liners of interest for ULSI applications is discussed. The adhesion strength of the Cu films on air exposed and in-situ deposited barrier layers, as well as the chemical state and composition of the interface were compared. The investigations also explored the effects of various ex-situ wet chemical and in-situ plasma clean techniques to enhance the adhesion of Cu. The adhesion strength was measured quantitatively by a stud pull test and a peel test using an adhesive tape.