A New Alternative Electrochemical Process for a Pre-Deposited UPD-Mn Mediated the Growth of Cu(Mn) Film by Controlling the Time during the Cu-SLRR

Abstract

A layer-by-layer deposition is essential for fabricating the Cu interconnects in a nanoscale-sized microelectronics because the gap-filling capability limits the film deposition step coverage on trenches/vias. Conventional layer-by-layer electrochemical deposition of Cu typically works by using two electrolytes, i.e., a sacrificial Pb electrolyte and a Cu electrolyte. However, the use of a Pb electrolyte is known to cause environmental issues. This study presents an Mn monolayer, which mediated the electrochemical growth of Cu(Mn) film through a sequence of alternating an underpotential deposition (UPD) of Mn, replacing the conventionally used UPD-Pb, with a surface-limited redox replacement (SLRR) of Cu. The use of the sacrificial Mn monolayer uniquely provides redox replacement by Cu2+ owing to the standard reductive potential differences. Repeating the sequence of the UPD-Mn followed by the SLRR-Cu enables Cu(Mn) film growth in an atomic layer growth manner. Further, controlling the time of open circuit potential (OCP) during the Cu-SLRR yields a technique to control the content of the resultant Cu(Mn) film. A longer OCP time caused more replacement of the UPD-Mn by the Cu2+, thus resulting in a Cu(Mn) film with a higher Cu concentration. The proposed layer-by-layer growth method offers a wet, chemistry-based deposition capable of fabricating Cu interconnects without the use of the barrier layer and can be of interest in microelectronics.

Flow Injection Electrochemical Quartz Crystal Microbalance with ICP-OES Detection: Recovery of Silver by Electrodeposition with Redox Replacement in a Flow Cell

“…31 In some of these studies, the elemental composition and total deposited amounts were calculated by removing the working electrode from the cell, and stripping off the deposited layer ex situ to analyze it through ICP-MS or ICP-OES. 25,27,29,32 Alternatively, metal recovery calculations were performed by analyzing the solution with ICP-MS before and after EDRR. 26 Static EQCM cells have also been used in EDRR and surface limited redox replacement (SLRR) studies to describe the electric potential and mass transients involved in deposition and redox replacement processes.…”