A Raman Spectroscopic Study of Barium Copper Oxide

The rate of nucleation and number density of nuclei of tin and tin-silver deposits on copper and nickel substrates in acid sulfate and acid methanesulfonate baths were measured by application of a nucleation model to chronoamperometric data. Based on the dependence of nucleation rate on overpotential, the critical Gibbs free energy of nucleation and the critical nucleation size were calculated. A mechanism of alloy nucleation in the presence of thiourea is proposed.

Section: Resultsmentioning

confidence: 99%

Nucleation of Tin and Tin–Silver Alloy on Copper and Nickel in Acid Plating Baths

Zhang

Barkey

2007

“…There are three possibilities for ac voltage to improve the quality of the mixed film. First, the chloride ion and H 2 O in NaCl solution may be involved in complexation with PT and copper, 20,21 filling some pinholes or defects in the mixed self-assembled film. Second, several authors reported that there is a small amount of metal dissolutions during the selfassembled process; 22,23 therefore, some Cu cations must retain in the mixed film.…”

Section: Resultsmentioning

confidence: 99%

Inhibition Effect of AC-Treated, Mixed Self-Assembled Film of Phenylthiourea and 1-Dodecanethiol on Copper Corrosion

Wang

Chen

Zhao

2004

A new method for preparing effective inhibition film on copper has been developed. Phenylthiourea was first adsorbed to a copper surface to form a self-assembled film. 1-Dodecanethiol was then self-assembled on the surface for subsequent modification. Finally, ac voltage was loaded on copper covered with the mixed film to further modify the film. After these procedures, an effective inhibition film was obtained as indicated by the low corrosion current density in polarization curves. High charge-transfer resistance in electrochemical impedance spectra reveals that the film hinders corrosion electrochemical reaction between the copper surface and NaCl solution. Film coverage on the copper surface is more than 99.0%, and inhibition efficiency is more than 97.2% in 0.5 mol dm Ϫ3 NaCl solutions. The mixed films before and after ac treatment are stable in a wide region of potentials. X-ray photoelectron spectroscopy analysis reveals that the effect of ac treatment may associate with the formation of a new complex compound.

“…TU can slowly reduce Cu 2+ and form complexes, Cu ͑TU͒ n + ͑n = 1-4͒, with the product; 23 the bonding of TU to the surface copper atoms is assumed to involve Cu-S bond formation. 24 The charge transfer resistance plot for copper deposition in the presence of TU shows a maximum, Fig. 10b, at ca.…”

Section: Sc • Nhmentioning

confidence: 97%

AC Impedance Investigation of Copper in Acid Solution

Burke

Sharna

2008

As demonstrated earlier in Part I of this work ͓L. D. Burke and R. Sharna, J. Electrochem. Soc., 155, D83 ͑2008͔͒, the electrochemistry of copper in an acid solution is complicated by the involvement of an active surface state of the metal, which undergoes an interfacial redox transition within the double-layer region, at ca. −0.7 V vs saturated mercury/mercury͑1͒ sulfate electrode. Commonly used bath additives in this area, e.g., PEG, Cl − , SPS, JGB, and thiourea, are assumed to influence the plating reaction by coordinating to the oxidized form of the active state couple. The nature of such interactions was explored, over an extended range of potentials in the plating region, for single additives and a limited range of mixed additives, using ac impedance. The involvement of the active surface state of the metal has received little attention in plating electrochemistry to date; its possible involvement in trench superfilling ͑or damascene copper plating͒ is outlined.