Akihiro Hosokawa

Real‐time temperature monitoring using a noncontact thermocouple for the next‐generation sputtering system

Real‐time temperature monitoring of the glass substrate and the shield using noncontact thermocouples has been demonstrated in the Applied Komatsu Technology physical vapor deposition sputtering system. The substrate temperature was monitored in real time within ±5 °C at 250 °C during a pure aluminum deposition. The noncontact thermometry for the glass substrate requires a correction to account for the influence of the susceptor temperature on the sensing element. The equation for the corrected temperature was determined by both experimental and analytical methods, and the correlation between the sensor and the substrate temperature was confirmed to be within ±2%. The shield temperature was monitored and controlled without any correction. The noncontact thermocouple has many practical applications in both high vacuum and high voltage environments.

Real-time substrate misalignment monitor and automatic recalibration

Real-time substrate misalignment monitoring and automatic position recalibration were demonstrated in the Applied Komatsu Technology physical vapor deposition cluster tool. To accomplish this, two techniques were used to detect substrate misalignment and determine the source of the error. The cluster tool consists of an atmospheric cassette load station, a load lock station, a transfer chamber, a preheat chamber and four process chambers. Accelerometers were installed at each module of the cluster tool to detect any unexpected vibration of the substrate as it is lowered into processing position. The substrate misalignment is monitored at the atmospheric cassette load station with a ±0.5 mm threshold value using an optical sensor. If excessive substrate misalignment is detected at the atmospheric cassette load station, the accelerometer data is used to determine which specific module of the cluster tool was operating improperly. Using the monitored misalignment value at the atmospheric cassette load statio...

Low temperature polysilicon chemical vapor deposition system for thin film transistor liquid crystal diode

Polysilicon thin film transistor (TFT)-based displays are increasingly found in cell phones, mobile communicators, PDAs, portable DVD players, and mobile computers because they have high resolution and low power consumption. The AKT plasma-enhanced chemical vapor deposition system made by Applied Materials is used to deposit multilayer dielectric films including precursor low-hydrogen-content amorphous silicon for manufacturing these displays. The polysilicon film is converted from an amorphous precursor film by an excimer laser annealing process. Production of a good quality polysilicon precursor film requires that the hydrogen content of the film be controlled below 2%. Achieving low hydrogen content requires uniform treatment at high temperature (500±10 °C) after deposition. This article describes the design and performance of the large, high temperature heat chamber integrated in a cluster-tool-based deposition system for both preheat and postannealing of the substrate. [Q. Shang, J. K. Kardokus, and ...

Rapid cooling dual slot load locks for liquid crystal display

Rapid cooling of 680×880 mm glass substrates was demonstrated in the dual-slot load locks [S. Kurita, W. Blonigan, and A. Hosokawa, U.S. Patent pending No. 7828.7017 (December 1999)] of an AKT 5500 chemical vapor deposition system. Two complimentary techniques are used to cool a substrate from 400 to 60 °C within 33 s while maintaining a temperature uniformity of ±5 °C. Helium equivalent to a partial pressure of 9 Torr is injected at the initial stage of venting. Cooling plates are located as close as 8 mm above and below the substrate while cooling. Rapid-cool dual-slot load locks reduce cost by eliminating large vacuum pumps and machine components. Uniform cooling eliminated undesirable thermal stress during cooling and thus enabled reliable substrate handling.