Yoshikazu Tanabe

Direct measurement of localized joule heating in silicon devices by means of newly developed high resolution IR microscopy

A high resolution IR microscope, especially designed for measuring localized joule heating effect in silicon devices, has been developed by combining a ZnS objective lens and a HgCdTe infrared detector. This microscope has achieved the practical spatial resolution of 10 mu m and practical temperature resolution of 0.24 K. With this IR microscope, the joule heating effect in poly-Si (polycrystalline silicon) thin film resistors formed on SiO/sub 2/ thin layer has been measured, simulating SOI (silicon on insulator) structures. A significant temperature rise was observed in this device structure, because of the low thermal conductivity of the SiO/sub 2/ layer, suggesting the possibility of new reliability problems caused by the joule heating effect in SOI structures.<<ETX>>

Diluted wet oxidation: a novel technique for ultra thin gate oxide formation

An ultra-pure water vapor generator that is compatible with RTP wet oxidation has been developed to meet the need for high quality gate oxides in deep sub-micron device process. This generator is based on a catalytic surface reaction of hydrogen gas and oxygen gas, and enables a precise control of H/sub 2/O/O/sub 2/ ratio in the processing gas at any desired percentage. Diluted Wet Oxidation (DWO) utilizes a low H/sub 2/O/O/sub 2/ ratio precisely controlled by the water vapor generator to obtain a low oxidation rate comparable to dry oxidation, which results in an accurate film thickness while maintaining the film characteristics of wet oxidation.

Surface inspection system with automatic discrimination of microscratches and particles on chemical mechanical polished wafers

Microscratches and particles are becoming a serious problem associated with the introduction of CMP to IC-processing. This paper describes a new surface inspection system for a blank wafer with emphasis on the discrimination technique between microscratches and particles. The system first detects both defects by means of the laser scattering technique as is the case of a conventional particle inspection tool, followed by a newly developed discrimination procedure based on the difference of angular distribution of the scattered light. The discrimination rate which is defined as the ratio of the correctly classified defects to the total defects detected was evaluated to be 85% or more on actual CMP-processed wafers.