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Title: In-situ spectroscopic ellipsometry study of copper selective-area atomic layer deposition on palladium

Selective area copper atomic layer deposition on palladium seed layers has been investigated with in-situ real-time spectroscopic ellipsometry to probe the adsorption/desorption and reaction characteristics of individual deposition cycles. The reactants are copper bis(2,2,6,6-tetramethyl-3,5-heptanedionate) vapor and hydrogen gas. Self-limiting atomic layer deposition was observed in the temperature range of 135–230 °C in a low pressure reactor. Under optimal conditions, growth occurs selectively on palladium and not on silicon dioxide or silicon nitride layers. Based on in-situ ellipsometry data and supporting experiments, a new mechanism for growth is proposed. In the proposed mechanism, precursor adsorption is reversible, and dissociatively adsorbed hydrogen are the stable surface intermediates between growth cycles. The mechanism is enabled by continuous diffusion of palladium from the seed layer into the deposited copper film and strong H* binding to palladium sites. Less intermixing can be obtained at low growth temperatures and short cycle times by minimizing Cu/Pd inter-diffusion.
Authors:
; ; ;  [1]
  1. Department of Chemical and Biomolecular Engineering University of Connecticut, Storrs, Connecticut 06269-3222 (United States)
Publication Date:
OSTI Identifier:
22318053
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films; Journal Volume: 32; Journal Issue: 4; Other Information: (c) 2014 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; COPPER; ELLIPSOMETRY; HYDROGEN; PALLADIUM; SILICON NITRIDES; SILICON OXIDES