Electrodeposition of Cu-Ag Film in Cyanide-Based Electrolyte

Abstract

Electromigration is considered a major concern of the decrease of Cu line reliability. Thus Copper-silver, a promising material for the next generation of interconnect in the aspect of electromigration resistance,has been studied. Electrodeposition in cyanide-based electrolyte was chosen as a Cu-Ag film formation method in this study. To carry out the electrodeposition, a linear sweep voltammetry was conducted to find an optimum reduction potential. Then, the Cu-Ag film was deposited with a static potential method. Film properties were investigated varying an applied potential, pH and electrolyte composition. High quality Cu-Ag film was obtained under the condition of - 1.6 V and pH 6.6. The composition of the film could be controlled by varying Ag concentration.

Preparation of Tunable Cu−Ag Nanostructures by Electrodeposition in a Deep Eutectic Solvent

“…[37] Nevertheless, we must consider for comparison that CuÀ Ag electrodeposition from aqueous media often employs metallic and/or Si working electrodes instead of carbon electrodes. [20,37,38] A study using a gas diffusion layer of carbon paper for the electrodeposition of CuÀ Ag from aqueous media exhibited the formation of wireshaped large particles covering the substrate. They observed that the presence of an additive provoked the wires to become porous and thinner, increasing the ECSA.…”

“…Our nanostructures are smaller and better distributed without agglomeration in comparison with the particles obtained in the literature from electrodeposition in aqueous media. Cu−Ag deposits from aqueous media commonly form films covering the whole substrate with agglomerated particles of irregular shape due to faster and uncontrolled deposition kinetics [20,21,37,38] . One of these studies also shows the formation of voids induced by hydrogen embrittlement [37] .…”

“…Cu−Ag deposits from aqueous media commonly form films covering the whole substrate with agglomerated particles of irregular shape due to faster and uncontrolled deposition kinetics [20,21,37,38] . One of these studies also shows the formation of voids induced by hydrogen embrittlement [37] . Nevertheless, we must consider for comparison that Cu−Ag electrodeposition from aqueous media often employs metallic and/or Si working electrodes instead of carbon electrodes [20,37,38] .…”

“…[34][35][36] For the electrodeposition of CuÀ Ag in aqueous media, cyanide-based electrolytes and other different additives have been commonly used to facilitate the deposition of both metals and to lead the growth of the NPs. [20,21,37] Since cyanide baths are extremely toxic, ammonia-based electrolytes have been proposed as a cyanide-free alternative for the electrodeposition of CuÀ Ag. [38] However, even though ammonia toxicity is lower than cyanide, it is a water contaminant in comparison with the non-toxic DES.…”

“…In addition to that, due to fast deposition kinetics in aqueous solution, undesirable growth mechanisms such as dendritic growth can occur, leading to a non‐homogenous deposit with low adherence [34–36] . For the electrodeposition of Cu−Ag in aqueous media, cyanide‐based electrolytes and other different additives have been commonly used to facilitate the deposition of both metals and to lead the growth of the NPs [20,21,37] . Since cyanide baths are extremely toxic, ammonia‐based electrolytes have been proposed as a cyanide‐free alternative for the electrodeposition of Cu−Ag [38] .…”