Comparative study on Cu-CVD nucleation using β-diketonato and amidinato precursors for sub-10-nm-thick continuous film growth

Kohei Shima, Hideharu Shimizu, Takeshi Momose, Yukihiro Shimogaki

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1 Citation (Scopus)

Abstract

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 β-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 × 1011 /cm2. The maximum nucleate density was achieved with the lowest deposition temperature and highest precursor concentration for both precursors; i.e., 6.9 ×1011 /cm2 for β-diketonato at 100°C, and 4.6 ×1011 /cm2 for amidinato at 150°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∼) 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.

Original languageEnglish
Pages (from-to)P305-P313
JournalECS Journal of Solid State Science and Technology
Volume4
Issue number8
DOIs
Publication statusPublished - 2015 Jan 1
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials

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