Review-In-Situ Surface X-ray Diffraction Studies of Copper Electrodes: Atomic-Scale Interface Structure and Growth Behavior



Gruender, Y ORCID: 0000-0002-5295-0927, Stettner, J and Magnussen, OM
(2018) Review-In-Situ Surface X-ray Diffraction Studies of Copper Electrodes: Atomic-Scale Interface Structure and Growth Behavior. JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 166 (1). D3049-D3057.

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Abstract

The electroplating of copper by the damascene process is the predominantly used technique for on-chip wiring in the fabrication of ultra-large scale integrated microchips. In this process, void-free superconformal filling of trenches is achieved by multicomponent electrolytes, containing chloride and organic additives in addition to the Cu ions. In this paper we review studies of the atomic-scale Cu interface structure and homoepitaxial Cu electrodeposition behavior in acidic (pH 1-3) Cl-containing electrolyte by in-situ surface X-ray diffraction. This technique provides detailed insight on the 3D atomic arrangement at the electrode surface and fast time-resolved data on the kinetic growth mode. On Cu(111) a complex potential-dependent adlayer structure is found, involving transitions between a chemisorbed oxygen species to a hexagonal close-packed incommensurate chloride adlayer. In contrast, on Cu(001) a simple disorder-order transition to a c(2 × 2) Cl adlayer is found. Parallel to the latter, a crossover from step-flow to layer-by-layer and finally 3D growth occurs during Cu(001) electrodeposition, indicating a decreasing Cu surface mobility toward more positive potentials. The presence of the organic additive polyethylene glycol (PEG) stabilizes the partial c(2 × 2) Cl adlayer on the Cu(001) surface and leads to an inhibition of Cu deposition with a tendency to rougher growth.

Item Type: Article
Depositing User: Symplectic Admin
Date Deposited: 19 Nov 2018 10:48
Last Modified: 19 Jan 2023 01:12
DOI: 10.1149/2.0071901jes
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3028929