Coating apparatus – Gas or vapor deposition – Having means to expose a portion of a substrate to coating...
Patent
1990-11-28
1993-07-06
Bueker, Richard
Coating apparatus
Gas or vapor deposition
Having means to expose a portion of a substrate to coating...
118715, 118725, 118728, 427239, 427237, 266252, 266254, 266255, 266258, C23C 1600
Patent
active
052249980
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to an apparatus for the oxidation treatment of metal, and particularly to an oxidation treatment apparatus for the passivation of metal tubular parts having a curved portion, which are to be used for ultra-high clean gas piping system or ultra-high vacuum equipment.
BACKGROUND OF THE INVENTION
In recent years, the technique for attaining ultra-high vacuum or the technique for producing ultra-high clean reduced pressure atmosphere by introducing a gas at a low flow rate into vacuum chamber is becoming increasingly important. These techniques are applied for the research of material characteristics, for the formation of various types of thin film, for the manufacture of semiconductor devices, etc. As the result, higher degree of vacuum is attained, while there is a strong demand on the reduced atmosphere, where the intermingling of impure elements and impure molecules could be reduced to utmost extent.
For example, in the manufacture of semiconductor devices, the dimensions of unit elements are being reduced year by year to attain higher integration of integrated circuit. Fervent research and development activities are carried out for the practical application of semiconductor devices having a dimension of 1 .mu.m to submicron, or 0.5 .mu.m or less.
Such semiconductor devices are manufactured by repeating the process for forming thin film and the etching process of the film thus formed into the specified circuit pattern. Usually, such processes are performed in ultra-high vacuum conditions or in reduced pressure atmospheres with the specified gas by placing the silicon wafers into the vacuum chamber. If the impurities are intermingled during these processes, the quality of thin film may be reduced or the precision fabrication may not be achieved. This is the reason why an ultra-high vacuum and an ultra-high clean reduced pressure atmosphere is wanted.
One of the major reasons hindering the actualization of an ultra-high vacuum and an ultra-high clean reduced pressure atmosphere has been the gas released from the surface of stainless steel widely used for the chamber of the gas pipe. Above all, the source of the worst contamination has been the moisture adsorbed on the surface, which is released under vacuum or reduced pressure atmosphere.
FIG. 9 is a graphic representation showing the relation between total leakage of the system, including the gas piping system and reaction chamber in each apparatus (the sum of gas quantity released from inner surface of the piping system and reaction chamber with the external leakage), and gas contamination. It is assumed that the original gas does not contain the impurities. The lines in the diagram indicate the results when the values are changed with gas flow rate as a parameter. Naturally, the lower the gas flow rate is, the more the impurities concentration increases as the influence of the released gas from the inner surface becomes conspicuous.
In the semiconductor manufacturing process, there is a trend to increasingly reduce the gas flow rate in order to attain a process of higher accuracy by opening and filling the holes with a high aspect ratio. For example, it is now normal to use the flow rate of several tens of cc/min. or less for the process of manufacturing ULSI of submicron order. Suppose that the flow rate is 10 cc/min. and that the total leakage of the system is 10.sup.-3 to 10.sup.-6 Torr l/sec. such as the apparatus currently in use, the purity of the gas is 1% to 10% ppm, this being far from the high clean process.
The present inventors have invented the ultra-high clean gas supply system and have succeeded in reducing the leakage from outside the system to less than 1.times.10.sup.-11 Torr l/sec. which is the detection limit of the detectors presently in use. However, the concentration of the impurities in the reduce pressure atmosphere could not be reduced due to the leakage from inside the system or due to the components of the related gas from the stainless steel surface. In the case of stainless st
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Mizokami Satoshi
Nakahara Fumio
Ohmi Tadahiro
Sugiyama Kazuhiko
Bueker Richard
Ohmi Tadahiro
Sanso Kogyo Kabushiki Kaisha
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