薄膜界面強度評価法の開発と先進LSI用銅薄膜のはく離への適用

概要

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This paper aims to develop a method for evaluating interface strength of thin films on a substrate of LSI chip. Although several methods have been proposed, plastic deformation and fracture of thin metal film bring ambiguity on the interface strength evaluated by the methods in use. In this study, a sandwich specimen, where the deformation of thin films is tightly constraint by substrate and steel bar, is proposed for preventing the plastic strain and the fracture. The validity is examined by experiments for the interface between copper conductor film (thickness: 300nm) and TaN barrier metal layer (thickness: 50nm) in an advanced LSI. The delamination crack initiates from the free edge of interface where the tensile singular stress field, δ=K_fγ^<-λ> (δ: stress and γ: distance from the edge), dominates. The criterion for the crack initiation is successfully evaluated as λ=0.08 and K_f=9MPa・m^λ by the results of the proposed experiment and the boundary element analysis.There is little fluctuation of strength among the experiments.
一般社団法人日本機械学会の論文
2000-08-25