Barrier-free Cu metallization with a novel copper seed layer containing various insoluble substances

This article reports novel copper seed layers containing various insoluble substances for applications in barrierless metallization. Based on XRD, FIB, TEM, SIMS, resistivity and leakage current measurement results, we conclude that the doping trace amounts of insoluble substances (W, WN) in the seed layer can inhibit the diffusion of copper into barrier-free Si, and that copper does not react with Si at temperatures up to ∼530 °C. Our results reveal that these layers can possibly be used in the advanced barrierless metallization process.