Comparative Study on Cu-CVD Nucleation Using beta-diketonato and Amidinato Precursors for Sub-10-nm-Thick Continuous Film Growth

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

来源：ECS Journal of Solid State Science and Technology, 2015, 4(8): P305-P313.

DOI：10.1149/2.0061508jss

We demonstrate the growth of sub-10-nm-thick continuous Cu films using chemical vapor deposition (CVD) for next-generation Cu interconnects for ultra-large-scale integration (ULSI). The thickness of such films is equivalent to that of Cu during coalescence, and optimized operating conditions and substrate materials are required to form high-density nucleates. Ru was used as an underlayer, and the time evolution of nucleation and grain growth were studied with systematically varied conditions using two Cu precursors: conventional beta-diketonato and newly developed amidinato precursor compounds. The revealed geometry of the initial nano-scale Cu grains prior to coalescence suggests the required nucleate density for 7-nm-thick continuous film growth, and which was 2.4 x 10(11) /cm(2). The maximum nucleate density was achieved with the lowest deposition temperature and highest precursor concentration for both precursors; i.e., 6.9 x 10(11) /cm(2) for beta-diketonato at 100 degrees C, and 4.6 x 10(11) /cm(2) for amidinato at 150 degrees C. A 10-nm-thick continuous Cu film was formed using amidinato under the optimized conditions. Furthermore, the framework used in this study to enable a high nucleate density suggests that it is possible to form thinner (4 nm similar to) Cu films using amidinato. Because of the inherent good step coverage of CVD, this process is a promising candidate for next-generation ULSI Cu interconnects.

• 出版日期2015