The need for a next-generation chemical mechanical polishing (CMP) slurry for copper planarization, to meet the requirements posed by advanced copper damascene processes, has led to the conception and development of a new type of slurry. The new “micelle slurry” is based on a mixture of surfactant and heteropolyacid, which takes the form of surfactant micelles enveloping the copper-reactive heteropolyacid. When used in the CMP process in place of conventional slurries, it effects copper planarization by a chemical mechanism with little or no mechanical abrasion. The mechanism enables a high rate of copper removal under low polishing pressures with minimal copper “dishing,” largely free from the scratching or erosion that may be encountered in CMP with conventional slurries due to their abrasive particle contents. These characteristics are advantageous for planarization of advanced copper damascene interconnects and particularly those including the relatively fragile low-k dielectrics. The micelle slurry also reduces the need for frequent dressing of foamed pads and enables a remarkably high rate of copper planarization with nonfoamed hard pads under low polishing pressures. It may therefore lengthen the pad service life and reduce the complexity and cost of CMP, particularly for copper damascene interconnects incorporating low-k dielectrics. © 2003 The Electrochemical Society. All rights reserved.
Summary:In order to clarify the active species of MoO3-Al2O3 catalyst for hydrocracking of diarylmethane, the effects of MoO3 content and calcination temperature on catalytic activity were studied. Moreover, changes in the hydrocracking behavior of diarylmethane over pretreated catalysts with water and aqueous ammonia were investigated.The catalytic activity increased with increasing MoO3 content, calcination temperature, and reduction time. Molybdenum oxide, which is extractable with aqueous ammonia but not extractable with water, was favorable for hydrocracking reaction.These results were well correlated with Giordano's study1). It was suggested that the main active species for hydrocracking were weak acidic sites formed by the reduction of octahedral Mo (VI) interacting with .Al2O3.
Summary: The catalytic hydrocracking of diarylmethane using 2, 5, 3'-trimethyldiphenylmethane (TMDPM) as a model compound was studied with a flow system at atmospheric pressure.MoO3-Al2O3 was found to be the most selective catalyst for the fission between methylene group and aryl groups in the preliminary studies on various catalysts. The effect of the calcination temperature, MoO3 content, the reduction time, and the addition of a third component on MoO3-Al2O3 was studied in detail.Results can be summarized as follows; 1. The catalytic activity was constant showing a maximum value at the calcination temperature range from 2. The catalytic activity and the ratio of fission (b/a) between the methylene group and two aryl groups increased with MoO3 content until it reached approximately 17wt%. However, further increase in the MoO3 content showed no effect any longer.
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