Papers by Author: Dae Chol Kwon

Abstract: As the electrodeposition reaction is a heterogeneous reaction including both material transfer and electrochemical reaction, this study tries to find out the reaction mechanism about Ag electrodepostion used as semiconductor interconnection using rotating disk electrode system (RDE system). Considering the environmental problem, non-cyanide Ag electrodeposition solution has been carried out. With varying the process conditions of a certain range including the rotating speed of RDE, applied voltage, and temperature etc., obtained the electrodeposition rate of Ag according to the reaction time. The rate determining step was clarified with the activation energy(Ea) of the electrodeposition reactions for the each process conditions estimated from Arrhenius Plot. Activation energy of Ag in the temperature range between 18°C and 32°C was 3.2kcal/mole. The electrodeposition rate of Ag seems to be controlled mass transport. With the electrodepositon solution mentioned above, the characteristics of silver thin film and bottom-up filling capability were investigated by DC or pulsed electrodeposition method. Especially, the effects of additives on the properties of bottom-up filling of Ag were studied.

Abstract: The thin film resistors such as Ni-Cr alloy could be formed by the electrodeposition method for embedded passive device in printed circuit board. A kinetic study on the electrodeposition of nickel-chromium alloy on copper has been performed using a rotating disk geometry. Activation energies of nickel and chromium in the temperature range between 15°C and 35°C were 8.9kcal/mole and 3.5kcal/mole, respectively. The electrodeposition rate of nickel seems to be controlled partly by electrochemical reaction and partly by mass transport, namely mixed controlled. However, that of chromium seems to be controlled by mass transport. As the amount of chromium in deposit increased, the electric resistance of deposit surface increased. The maximum electric resistance of nickel-chromium alloy deposit was 78.6Ω /□.

Abstract: The purpose of this study is to develop non nitric acid desmut to cope with environment regulation and at the same time, to obtain the effect comparable to nitric acid in removing smut. For this, some desmut solutions were produced adding 2~3 chemical reagents to basic components such as peroxide, ammonium group, ferric group compounds and acid. And, electrochemical treatment was tried to remove ammoniacal nitrogen(NH3-N) in desmut solution after desmut treatment. Consequently, we could gain smut-removing ratio of 90% using the solution mixed with peroxide, ammonium group, ferric group compounds and sulfuric acid at 35°C for 70 seconds, and the ratio is almost the same with that using nitric acid type desmut solution. In this work, most nitrogen(T-N) was confirmed to be ammoniacal nitrogen(NH3-N). In addition, we succeeded in controlling ammonia-nitrogen below 60 ppm corresponding to environment regulation by electrochemical treatment in the wastewater.