Browsing by Author "Chiang, Wei-Shen"

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Formation of Cu/MnOx composite film by concurrent electroplating and electrophoresis in an organic solvent
(2018-08-30)
Chiang, Wei-Shen
;
Huang, Jun-Qian
;
Tso, Kuang-Chih
;
Hung, Pei-Sung
;
Chen, Po-Chun
A composite Cu/MnOx thin film was fabricated by conducting electroplating of Cu and electrophoresis of MnOx colloids simultaneously in an organic electrolyte. The organic electrolyte was prepared by dissolving copper (II) acetylacetonate and manganese (II) acetylacetonate in ethylene glycol, with addition of 10 vol% acetic acid to improve ionic conductivity. Since both Cu ions and MnOx colloids carry positive charges, the formation of a composite film was achieved by a pulse current mode in which a low current pulse was used for Cu2+ reduction, followed by a high current pulse for the electrophoresis of the MnOx colloids. The Cu/MnOx composite film was dense and its X-ray diffraction pattern revealed a mixture of Cu, Mn2O3, and Mn3O4. Both X-ray photoelectron spectroscopy and X-ray absorption spectroscopy show consistent results confirming the metallic nature of Cu and oxidized state of Mn.
Pulse electrodeposition of copper-manganese alloy in deep eutectic solvent
(2018-04-25)
Chiang, Wei-Shen
;
Huang, Jun-Qian
;
Chen, Po-Chun
;
Wu, Pu-Wei
;
Joi, Aniruddha
Copper-manganese alloy has been established to improve resistance toward electromigration for interconnects. In this work, we employ a deep eutectic solvent (DES) to formulate a nonaqueous electrolyte for pulse current electrodeposition of Cu-Mn alloyed film. Using impedance spectroscopy to record ionic conductivities of DES-based electrolytes, we determine the optimized bath with a Cu/Mn molar ratio of 1:20. We produce an uniform, smooth, and composition-controllable CuMn alloyed film after exploring various pulsing parameters. Signals from X-ray diffractometer (XRD) suggest successful alloying of Cu and Mn with minor presence of MnO2. Profiles from X-ray photoelectron spectroscopy (XPS) validate the metallic nature of Mn from the as-deposited film. Upon Ar annealing, both XRD and XPS exhibit strong signals of MnO2 formation. In addition, images from transmission electron microscope and qualitative elemental chemical mapping indicate Mn atoms in CuMn alloy either diffuse through the underlying Cu seed layer and segregate at the Cu/SiO2 interface, or migrate toward the external surface forming MnO2. (C) 2018 Elsevier B.V. All rights reserved.