A direct electrodeposition technique for Cu nanotube array fabrication and the subsequent conversion of the deposited Cu into Cu2O was developed. The Cu2O nanotube arrays showed high capacity, cyclability, and rate capability. The cycling performance of the Cu2O nanotubes showed a high level of structural integrity with capacity retention even after 94 cycles when cycled at 1C to 3C rates. The enhanced electrochemical performance of the Cu2O nanotubes came from a high surface area, electrolyte access, high electrical conductivity of Cu core support, and structural integrity of the oxide shell active material.

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While dual damascene integration for current technologies is often cited for its challenges in regard to patterning and demands on lithography hard-and software. Metallization for features with aspect ratios in the range of 4:1 as well as line widths with 40nm and shrinking is thought to be manageable with established technologies. Void free fill of lines and vias is mandatory yet reliability and line resistance gaining importance from one technology node to the next. Methods to enhance reliability are abound however which of the solutions are extendible to future technology nodes depends on a variety of parameters. The before mentioned topics on metallization challenges as well as choices to enhance reliability will be discussed in the paper.

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Stress changes in electrodeposited copper films during room temperature aging were monitored by measuring the bending of the substrate using an optical fiber displacement sensor. Electrodeposition was carried out galvanostatically on evaporated copper films on borosilicate glass substrates in a stirred acidic copper sulphate bath at room temperature. It was observed that stress increases rapidly in the tensile direction reaching a plateau after ~1 hour of room temperature aging. The magnitude of the change was observed to increase with increasing current density but to decrease with increasing film thickness. The effect of additives to the bath was investigated. Films deposited in the presence of added chloride ions subsequently showed an increased change in stress during room-temperature aging but the effect did not increase significantly with concentration. Films deposited with BTA as an additive also showed an increased change in stress during aging and the effect increased significantly with increasing concentration. The effect of added PEG was small while the addition of thiourea had a significant and complex effect.