Cooper appears to offer better conductivity and reliability in ULSI metallization than aluminum, and the current research confirms copper potential in this regard. ULSI metallization is accomplished by electrodepositing copper from ethylenediamine complex baths using the additives glycine, ammonium sulfate, and a small quantity of thiodiglycollic acid. These baths produce good throwing powder and fill trenches and contact holes on silicon wafers with giant grains of void-free copper deposits. ULSI metallization using copper produced no voids as are formed due to the absorption of polyethylene glycol in the presence of chloride ions, thus avoiding a major drawback of ULSI metallization. Results of the current research have demonstrated the potential for use of copper in ULSI metallization accomplished through electrodeposition of copper using ethylenediamine complex baths.
To obtain a fundamental information about the mechanism of corrosion inhibition for mild steel by polyacrylic acid systems in cooling water systems, the effects of a simple model, i, e., a mixture system composed of polyacrylic acid and polyacrylamide (PAA/PAAm), on the corrosion of mild steel was investigated. Results indicated that the mixture system effectively inhibits corrosion. This effectiveness is attributed to the formation of polymer-polymer complex (PPC) and its action.
Preparation of a photosensitive composite electrode for an electrolytic cell aimed at energy conversion and photoredox reactions was attempted using the method of dispersion plating. Watt's bath containing photosensitive silver bromide powder as the dispersoid was used for dispersion plating. The conditions of current density, pH, and the rotation rate of the plating bath were investigated for the codeposition of matrix and dispersoid for preferable surface of the photosensitive electrode. The AgBr content also changed when these conditions changed. It was proven that were optimum conditions. The AgBr content increased about 1.6 times by addition of cationic surface active agent in comparison with the case that was not added. The composite electrode showed photosensitivity on the cyclic voltammetry under illumination by chopped light of Xe discharging lamp.
In order to obtain a SiO2 layer as a catalyst support on a surface of aluminum, silica coating on an anodized aluminum plate has been investigated. The catalyst support plate was prepared by impregnating an anodized aluminum plate into silica sol and calcinating it. Results indicated that adding oxalic acid to silica sol is effective in increasing the amount of silica, but adding other acids to the sol form a gel within 100h. The amount of silica applied increases with an increase in the temperature and the impregnation time. However, the amount decreased as the amount of alumina layer that had dissolved increased. The BET surface area of the coated specimens increased as the Si content increased. The maximum surface area relative to the apparent geometrical surface area was approximately 6000m2·m-2, which was more than twice that before coating, demonstrating that it is possible to apply the coating as a catalyst support. Results of plate characterization indicated that the alumina layer formed by anodizing dissolved in the presence of oxalic acids enlarging the pores that were then filled with silica particles.
The outer face of copper tubes used in a heat exchanger were coated with tin. The tubes were brazed with various types of solder in order to evaluate their corrosion resistance in a H2S gas environment. Results indicated that a copper tube coated with tin and brased with Sn-Pb and Sn-Ag demonstrates better corrosion resistance than conventional tubes.