High-aspect-ratio SiO 2 contact-hole etching is one of the key processes in the fabrication of ultralarge-scale integrated devices. However, there are many serious problems, such as charge-buildup damage, etching-stop, and microloading effects. Charge accumulation in high-aspect-ratio contact holes during etching is one of the main causes of these problems. In SiO 2 etching using fluorocarbon gases, it is well known that fluorocarbon film is deposited on the underlayer surface and sidewall of contact holes. It is expected that such deposited fluorocarbon polymer will exert a great influence on the etching characteristics and charge accumulation in SiO 2 contact holes. Therefore, it is necessary to measure the conductivity of the sidewall surfaces of contact holes with deposited fluorocarbon polymer. We made a monitoring device on a silicon wafer to evaluate the sidewall current of SiO 2 contact holes and determined the relationship between the chemical structure and electrical conductivity of the fluorocarbon films deposited in the contact holes as a function of fluorocarbon gases and incident ion flux. We found that the electrical conductivity of the sidewall surface in SiO 2 contact holes depends on the chemical structure of the deposited fluorocarbon polymer. It was also clear that the chemical structure of the deposited fluorocarbon polymer depended on nature of the radical species and ion flux incident on the etching surface. These results indicate that by controlling the chemical structure of the deposited fluorocarbon polymer one may be able to mitigate the influence of charge accumulation.

A new type insulation diagnostic system has been developed that makes automatic measurements of dielectric dissipation factor and dc component in a hot-line XLPE cable and makes an overall judgment of cable insulation deterioration. This system was tested on XLPE cables in hot-line conditions, the criteria for judgment of insulation deterioration were established based on the results o f measurements.

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In situ on-wafer monitoring of the electron and ion energies at the contact-hole bottom is primarily achieved in Ar ultrahigh-frequency plasma. The on-wafer probe reveals a lower electron density and higher electron temperature at the contact-hole bottom due to the electron-shading effect, as compared with that in the bulk plasma. The on-wafer probe also shows the ion energy distribution function (IEDF) at the contact-hole bottom. The peak energy of IEDF corresponded to the sheath potential. Accordingly, the authors found that the on-wafer probe is a very effective tool for investigating the electron and ion energies in real SiO2 contact structures.

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