Cozy Ban

Impact of Organic Contaminants from the Environment on Electrical Characteristics of Thin Gate Oxides

We have investigated the impact of organic contaminants from the environment on the electrical characteristics of gate oxides by evaluation of electrical characteristics of metal oxide semiconductor (MOS) capacitors and gas chromatography-mass spectrometry following thermodesorption (TD-GC/MS) analysis of organic species adsorbed on silicon surfaces. It was found that organic contaminants from the environment adsorbed on silicon surfaces deteriorate gate oxide reliability; the increase in both breakdown and infant failure of gate oxides is enhanced by organic contaminants from the environment and depends on gate oxide thickness and the kind of silicon substrate. These results are useful for clarifying the deterioration mechanism of gate oxides caused by organic contaminants on silicon surfaces.

Advanced water purification system for sub-half-micron devices

Summary form only given. Sub-half-micron devices have fine patterns and thin films. Therefore, the wafer surface is very sensitive to contamination. It is important to keep the wafer surface clean for producing high yield. Purified water plays a significant role in cleaning silicon wafers, because wafers are rinsed with water at the end of every process. So water, the final cleaning agent, has to be highly purified. In current water purifying systems, it is difficult to accomplish the water quality targets for sub-half-micron devices. We developed a new water purification system with three new technological innovations: the ion exchange resins capable of absorbing particles, the unit to ionize silicate impurities, and a two-stage vacuum tower. Optimal organization of these technologies makes it possible to achieve the highest purity with reduced cost. We present the technologies on effective removal of particles, efficient elimination of silicate impurities, and strict control of dissolved oxygen.