Effect of Additives on the Microstructure of Electroplated Tin Films

Abstract

Electroplated tin films are important for several technologies such as microelectronics, Li-ion batteries, and corrosion-resistant coatings. In this paper, we demonstrate that the microstructure of tin films can be precisely controlled by addition of certain combinations of organic additives to a methanesulfonic acid based electroplating bath. Tin films are deposited on a copper substrate by varying the concentrations of two such additives, namely, hydroquinone and gelatin. The plating process is characterized by linear sweep voltammetry and insights into the resulting microstructure are obtained using imaging by scanning electron microscopy. It is found that the addition of hydroquinone alone results in non-uniform tin films having significant dendrites and does not affect the hydrogen gas evolution during electroplating. The addition of gelatin alone is found to suppress the evolution of hydrogen gas and affects the film nucleation process that controls its grain morphology, but also creates pinholes in the film and sludge in the bath. A combination of the two additives, however, yields a highly uniform grain structure with little to no dendrite formation and a delayed onset of hydrogen gas evolution, which is highly desirable during the electroplating process. Experiments are carried out that show that the mechanism of tin film nucleation and growth during electroplating is altered in the presence of the additives, where gelatin suppresses the tin nucleation rate (thereby controlling the grain size) as well as the formation of large dendrites; while hydroquinone, acting as an antioxidant, prevents pinholes, creates a uniform film, and avoids sludge formation in the presence of gelatin. This work demonstrates a path to control electroplated tin microstructures by varying bath chemistries and process parameters which will prove highly useful to industry.) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.237.114.176 Downloaded on 2018-12-20 to IP Journal of The Electrochemical Society, 165 (16) D816-D824 (2018) D817 ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.237.114.176 Downloaded on 2018-12-20 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.237.114.176 Downloaded on 2018-12-20 to IP

Early-Stage Growth Mechanism and Synthesis Conditions-Dependent Morphology of Nanocrystalline Bi Films Electrodeposited from Perchlorate Electrolyte

“…Thus, as the current density increases, the crystallite orientation changes towards decreasing the texture axis indices, which was shown in our previous work [ 52 ]. Such microstructural behavior was observed in electrodeposited Ni-Co films, where the presence of texture axes was noticed depending on the pH value of the electrolyte [ 61 ] and in work [ 62 ] during the electrodeposition of Sn with a layered microstructure with the introduction of various organic additives.…”

Effect of Glue, Thiourea, and Chloride on the Electrochemical Reduction in CuSO4–H2SO4 Solutions

“…Considering that the electrodeposition of the metal species happens only on the additive-free cathodic surface, the current density measured in the base solution, i, can be directly related to the maximum cathodic surface available for reduction. Then, the fraction of the cathodic surface covered by the adsorption of additives, θ, can be estimated as a function of the current density, i * , measured in the presence of additives, so that [41]:…”

Mechanism of surface rust defects on tinplate strip steel during storage and transportation

“…Wang 10 applied scanning electron microscopy, adhesion tests assessments to evaluate the effects of passivation process parameters—like resistance to flow, paint film adhesion and film thickness—on rust resistance. Arafat 11 examined the influence of additives on Sn coating grain size, hydrogen evolution, tin sludge and process defects like pinholes. Reis and others 12–15 used electrochemical impedance spectroscopy (EIS), x-ray diffraction and other techniques to analyse the rust rate and electrical parameters of tinplate in various food packaging environments, like corn and citric acid, determining the rust mechanisms under different real-world storage conditions.…”