Atomic layer deposition of ruthenium (Ru) thin films using ethylbenzen-cyclohexadiene Ru(0) as a seed layer for copper metallization

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• 作者：Seungmin Yeo ; Sang-Hyeok Choi ; Ji-Yoon Park ; Soo-Hyun Kim ; Taehoon Cheon ; Byoung-Yong Lim ; Sunjung Kim
• 关键词：Ruthenium ; Atomic layer deposition ; Nucleation ; Seed layer
• 刊名：Thin Solid Films
• 出版年：2013
• 出版时间：1 November, 2013
• 年：2013
• 卷：546
• 期：Complete
• 页码：2-8
• 全文大小：1285 K

文摘

Ruthenium (Ru) thin films were grown on thermally-grown SiO₂ substrates using atomic layer deposition (ALD) by a sequential supply of (ethylbenzene)(1,3-cyclohexadiene)Ru(0) (EBCHDRu, C₁₄H₁₈Ru), and molecular oxygen (O₂) at deposition temperatures ranging from 140 to 350 ¡ãC. A self-limiting film growth was confirmed at the deposition temperature of 225 ¡ãC and the growth rate was 0.1 nm/cycle on the SiO₂ substrate with a negligible number of incubation cycles (approximately 2 cycles). Plan-view transmission electron microscopy analysis showed that nucleation was started after only 3 ALD cycles and the maximum nuclei density of 1.43 ¡Á 10¹²/cm² was obtained after 5 ALD cycles. A continuous Ru film with a thickness of ~ 4 nm was formed after 40 ALD cycles. The film resistivity was decreased with increasing deposition temperature, which was closely related to its crystallinity, microstructure, and density, and the minimum resistivity of ~ 14 ¦Ì¦¸-cm was obtained at the deposition temperature of 310 ¡ãC. The step coverage was approximately 100 % at trench (aspect ratio: 4.5) with the top opening size of ~ 25 nm. Finally, the ALD-Ru film was evaluated in terms of its performance as a seed layer for Cu electroplating.