Effects of P on amorphous chemical vapor deposition Ru-P alloy films for Cu interconnect liner applications

Jinhong Shin, Hyun Woo Kim, Kyriacos Agapiou, Richard A. Jones, Gyeong S. Hwang, John G. Ekerdt

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

Amorphous Ru(P) films grown by chemical vapor deposition at 575 K using a single source precursor, cis -RuH2 (P (CH3) 3) 4, or dual sources, Ru3 (CO) 12 and P (CH3) 3 or P (C6 H5) 3, are studied. The phosphorus percentage affects the film microstructure, and incorporating >13% P resulted in amorphous Ru(P) films. While codosing P (CH3) 3 with Ru3 (CO) 12 improves film step coverage, the most conformal Ru(P) film is obtained with cis -RuH2 (P (CH3) 3) 4. A fully continuous 5 nm Ru(P) film is formed within 1 μm deep, 8:1 aspect ratio trenches. The barrier performance is tested using Cu/Ru/Si(100) stacks annealed at 575 K, and sheet resistance was used as a measure of barrier failure. Cu diffusivity in physical vapor deposition (PVD) Ru is approximated to be 6.6× 10-17 cm2 /s at 575 K, which indicates fast Cu diffusion along the grain boundaries. While 26 nm polycrystalline PVD Ru failed after 6 h annealing by Cu penetration, 28 nm amorphous Ru(P) survived after 67 h annealing. First principles density functional calculations suggest 16.7% P degraded the adhesion strength by 12% when compared to crystalline Cu/Ru, by the presence of P at the interface. However, due to the strong Ru-Cu bonds, amorphous Ru(P) still forms a stronger interface with Cu than do Ta and TaN to Cu, as observed when annealing 10 nm Cu films on these surfaces at 675 K.

Original languageEnglish
Pages (from-to)974-979
Number of pages6
JournalJournal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
Volume26
Issue number4
DOIs
StatePublished - 2008

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