Influence of alkylpyridinium ionic liquids on copper electrodeposition from acidic sulfate electrolyte

The effect of two alkylpyridinium ionic liquids （py-iLs） including N-butylpyridinium hydrogen sulfate （BpyHSO4） and N-hexylpyridinium hydrogen sulfate （HpyHSO4） on the kinetics of copper electrodeposition from acidic sulfate solution was investigated by cyclic voltammetry and potentiodynamic polarization measurements. Results from cyclic voltammetry indicate that these py-iLs have a pronounced inhibiting effect on CuE＋ electroreduction and there exists a typical nucleation and growth process. Kinetic parameters such as Tafel slope, transfer coefficient and exchange current density obtained from Tafel plots, lead to the conclusion that py-iLs inhibit the charge transfer by slightly changing the copper electrodeposition mechanism through their adsorption on the cathodic surface. In addition, scanning electron microscope （SEM） and X-ray diffraction analyses reveal that the presence of these additives leads to more leveled and fine-grained cathodic deposits without changing the crystal structure of the electrodeposited copper but strongly affects the crystallographic orientation by significantly inhibiting the growth of （111）, （200） and （311） planes.

Microstructure and crystallographic characteristics of nanocrystalline copper prepared from acetate solutions by electrodeposition technique

Methane sulphonic acid is an alternative electrolyte for conventional sulphuric acid for copper deposition.Theelectrodeposition of copper from eco-friendly acetate-based electrolytes consisting of copper acetate,sodium acetate and methanesulphonic acid was dealt.Thamine hydrochloride(THC),saccharin and4-amino-3-hydroxynaphthalene1-suphonic acid were used asadditives in depositing electrolytes.The cathode current efficiency was calculated using the Faraday’s law.Metal distrbution ratio ofthe solutions was determined using Haring?Blum cell.These additives impact the surface morphology of deposited copper films bydowngrading,the grain size was analyzed by scanning electron microscopy(SEM)and X-ray diffiraction technique.XRD patternacquired for electrodeposited copper film shows polycrystalline and face centered cubic structure(FCC).The crystal size of thecopper film was calculated using the Debye?Scherrer’s equation.The crystal size revealed that deposits produced from additivecontaining electrolytes exhibited the lowest grain size.Texture coefficient analysis studies revealed that all copper film deposits arepolycrystalline and the crystals are preferentially oriented and parallel to the surface.A uniform and pin-hole free surfacemorphology and grain refining were brought about by the additives.

On the Role of Boric Acid in the Copper-Tin Alloy Bath

The role of boric acid in the copper tin alloy bath has been investigated by means of the cathodic polarization curves,cyclic voltammograms,rate of alloy electrodeposition and morphological analysis of deposits.The results indicate that the presence of boric acid in weak acidic solution for electrodeposition of Cu Sn alloy raises the overvoltage of hydrogen discharge and lowers the overvoltage of Cu,Sn and Cu Sn alloy deposition on the Pt,and accelerates the rate of depostion.Boric acid was adsorbed on the surface of cathode and inhibited reduction of hydrogen,then the adsorbed boric acid promoted electrodeposition of metals as a catalyzator.However,as the concentration of boric acid is more than 0.50 mol/L,the above effect was weakened due to the complexation reaction between the excessive boric acid and metallic ions.

Trace bis-(3-sulfopropyl)-disulfide enhanced electrodeposited copper foils

Smooth and strong copper foils are highly required for the development of printed circuit boards and Li-ion batteries.Adding additives is an efficient and low-cost method to enhance electrodeposited copper foils.Here we chose Bis-(3-sulfopropyl)-disulfide(SPS)as the additive and investigated its concentration on the surface roughness and tensile strength of the electrodeposited copper foils.A copper foil with the smoothest surface(Rz=2.1μm)and the highest tensile strength(~338 MPa)was prepared with1.5 mg/L SPS.The contact angle on the copper foil decreased with the reduction of surface roughness.The enhancing mechanism of the SPS was investigated by scanning electron microscopy and X-ray diffraction.The refined grain and enhanced(220)texture were considered to be the radical reason for the smooth and strong copper foils.The electrochemical results prove the suppressing effect is related to the SPS adsorption.