Study on the Adhesion Strength of CVD-Cu Films with ALD-Co(W) Underlayers Made Using Amidinato Precursors

作者：Shima Kohei^*; Shimizu Hideharu; Momose Takeshi; Shimogaki Yukihiro

来源：ECS Journal of Solid State Science and Technology, 2015, 4(2): P20-P29.

DOI：10.1149/2.0061502jss

We investigated the adhesion strength of Cu films grown using chemical vapor deposition (CVD) on a Co(W) layer, which was grown using atomic layer deposition (ALD), for Cu interconnect applications in. ultra-large scale integration (ULSI). Co(W) forms an effective bather to the diffusion of Cu and forms an adhesion layer in a single bather. Amidinato precursors were used in the deposition of Co and W, which contain neither O nor F, and yielded high-purity Co(W) films. Furthermore, the use of an amidinato Cu precursor was also found to be important in enabling Cu deposition without interfacial contamination. The W content of the Co(W) layer was optimized to 14 at% via an evaluation of the diffusion barrier properties, the electrical conductivity, and the adhesion strength with the Cu layer. A CVD-Cu/ALD-Co(W) stack was formed using amidinato precursors for the growth of both films, and was found to exhibit favorable properties compared with a conventional PVD-Cu/PVD-Ta/TaN stack. It was also favorable to a PVD-Cu/PVD-Ru/TaN stack in terms of the diffusion barrier properties and electrical conductivity, with a similar adhesion strength for Cu. For these reasons, our Co(W) films have potential applications in reliable and high-performance Cu interconnects in next-generation ULSI.

• 出版日期2015