Raman and DFT Study of the Reaction of Hydrazine and Hypophosphite on a Cu Surface in the Electroless Deposition Process

Abstract

Oxidation of the reductants is a dominant factor in the electroless deposition process. In order to obtain fundamental knowledge about the reaction mechanism of reductant oxidation for more precise control of the solid-liquid interface in this process, we have attempted to characterize the behavior of reductants adsorbed on Cu surface by using plasmon antenna enhanced Raman scattering. The concentric-patterned antenna coated with Cu, which consisted of a dimple array with single hole or a single hole with coaxial dimples, was designed by Finite Difference Time Domain (FDTD) calculation to enhance the electric field by focusing surface plasmons. By using this antenna and comparing the spectra to the results of Density Functional Theory (DFT) calculations, Raman peaks of adsorbed reductants on Cu were identified. Furthermore, we examined the conformation of adsorbed reductants by DFT calculation of the adsorption model of reductants on fcc-Cu(111) surface. As a result, the nature of reductant adsorption on Cu surface has been investigated from a computational point of view and an experimental point of view, and such in-situ characterization will be useful for analysis of a variety of systems at solid-liquid interface.

30 years of electroless plating for semiconductor and polymer micro-systems

“…The application of electroless Co film to magnetic recording media was first proposed by Electroless NiP film [110] [111,112]. Moreover, they studied the behavior of reductants adsorbed to the Cu surface by plasmon antenna enhanced Raman scattering and modeled this effect by Density Functional Theory (DFT) calculation [113].…”

Electroless Metallization of the Elements: Survey and Progress

“…490 Although Cu is prone to oxidation and exhibits a weaker SERS response than Au, it also readily chemisorbs a variety of organic analytes that favors its use for repetitive routine analyses. 491 The conformal nature of EL deposition is ideally suited for the fabrication of effective S E R S s u b s t r a t e s u s i n g n a n o s t r u c t u r e d t e mplates, 91,482,483,492,493 which require the deposition of reproducible, uniform metal surfaces to replicate the template structure.…”

“…Experimental evidence indicates that the H • (ads) species can react to form H 2 via eq , which is released from the surface, or reduce Ni II to Ni I via eq , which disproportionates to deposit additional Ni 0 metal per eq : In closing this section, we note the extensive DFT molecular modeling and experimental work concerning H 2 PO 2 – oxidation spanning more than two decades to date by the Homma group. ,− These researchers have utilized DFT modeling, in conjunction with plasmon-enhanced Raman measurements, to better understand and observe H 2 PO 2 – intermediates present during the oxidation reaction. Their efforts have demonstrated that oxidation requires the formation of 5-coordinate, rather than 3-coordinate, intermediates.…”

Electrochemical Processes for the Fabrication of Functional Micro–nano Structures and Devices: Mechanistic Understanding and Process Development

“…We also attempted to develop an approach to combine in situ surface-enhanced Raman spectroscopy with theoretical calculations for analyzing the behavior of reductants and additives in detail, [25][26][27] and these approaches will provide possibilities to achieve further precise control of deposition.…”