Material or article handling – Apparatus for moving material between zones having different... – Including serially arranged valves in path having a vertical...
Reexamination Certificate
1999-03-18
2001-05-15
Fischetti, Joseph A. (Department: 3652)
Material or article handling
Apparatus for moving material between zones having different...
Including serially arranged valves in path having a vertical...
C414S805000, C414S935000, C414S938000, C414S411000
Reexamination Certificate
active
06231290
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a processing method for a substrate and a processing unit for a substrate.
2. Disclosure of the Prior Art
Processes for manufacturing semiconductor devices include steps in which semiconductors as substrates undergo processes such as oxidation, diffusion, CVD (Chemical Vapor Deposition) or the like. Thermal processing units are often used for conducting the various processes. A conventional thermal processing unit comprises: an operation area where an operator or an automatic conveying robot holds and conveys a carrier housing semiconductor wafers, and a loading area where semiconductor wafers in the carrier are transferred to a wafer-boat as a holder of substrates which is then loaded into or unloaded from a thermal processing furnace.
In such thermal processing units, it is preferable for a partition (bulkhead) to be provided between the operation area which is exposed to the atmosphere and the loading area. The partition allows the loading area to remain cleaner than the operation area and prevents a natural oxidation film from forming on the semiconductor wafers. The loading area should also be preferably filled with an inert gas such as nitrogen. A closed-type carrier, whose entrance for semiconductor wafers can be hermetically closed by a lid, should also be preferably used in the thermal processing unit in order to prevent the semiconductor wafers from being contaminated with particles.
An opening is provided in the partition between the operation area and the loading area. A door is provided at the opening to open and close it. When processing the semiconductor wafers, the lid of the carrier is aligned to be in contact with the opening, and the door and the lid are opened to communicate the interior of the carrier with the loading area. The semiconductor wafers are then conveyed from the interior of the carrier to the wafer-boat in the loading area via the opening. The wafer-boat is then loaded in the thermal processing furnace to perform the prescribed processes on the semiconductor wafers. The way of opening the door and the lid together is described in Japanese Patent Laid-Open No. 8-279546.
The interior of the carrier is full of the atmospheric air unless it is filled with another gas such as an inert gas. Because of this, the air in the carrier may flow into the loading area when the carrier is aligned with the opening and the door and the lid are opened. The concentration of the oxygen in the loading area increases if the air in the carrier flows into the loading area. This makes the replacement of the atmospheric air with an inert gas more time-consuming and increases the possibility of oxidation film forming on the semiconductor wafers. This may have a bad effect on processing.
SUMMARY OF THE INVENTION
Therefore, the object of this invention is to provide a processing unit and method for a substrate, which can perform the process of the substrate without increasing the concentration of the oxygen in the loading area by preventing the leakage of the air from the operation area into the loading area.
To achieve the above objects, this invention is characterized by a feature whrein a processing unit for a substrate comprises: a partition provided between an atmospheric area and an inert gas area, and having an opening to communicate the atmospheric area with the inert gas area, an door provided above the opening to open and close it, carrier holding means for holding a carrier of the substrate in such a manner that the carrier comes in contact with the opening on the side of the atmospheric area, and inert gas replacing means for replacing a gas in the carrier with an inert gas by introducing the inert gas into the carrier when the door closes the opening and the carrier comes in contact with the opening on the side of the atmospheric area by the carrier holding means.
In addition, to achieve the above objects, this invention is characterized by a feature wherein a processing method for a substrate by using a processing unit for the substrate comprising: a partition provided between an atmospheric area and an inert gas area, and having an opening to communicate the atmospheric area with the inert gas area, an door provided above the opening to open and close it, carrier holding means for holding a carrier of the substrate in such a manner that the carrier comes in contact with the opening on the side of the atmospheric area, and inert gas replacing means for replacing a gas in the carrier with an inert gas by introducing the inert gas into the carrier when the door closes the opening and the carrier comes in contact with the opening on the side of the atmospheric area by the carrier holding means, comprises; a step of closing the opening by the door, a step of holding the carrier including the substrate by the carrier holding means in such a manner that the carrier comes in contact with the opening on the side of the atmospheric area, a step of replacing the gas in the carrier with the inert gas by the inert gas replacing means, and a step of opening the door to communicate the interior of the carrier replaced with the inert gas with the inert gas area via the opening.
According to these features, the process of the substrate can be performed without increasing the concentration of the oxygen in the loading area by preventing the leakage of the air from the operation area into the loading area.
Preferably, the carrier may have an opening part to communicate with the opening when the carrier comes in contact with the opening on the side of the atmospheric area, and the inert gas replacing means may have an inert gas supplying hole and a gas exhausting hole which are openly provided in the opening.
Preferably, the carrier may have a lid to open and close the opening part of the carrier.
Preferably, a lid opening-closing mechanism may be mounted on the door for holding the lid of the carrier and for opening and closing it.
Preferably, a door opening-closing mechanism may be mounted on the partition for opening and closing the door, and the door opening-closing mechanism may be adapted to open the door in a state where the lid opening-closing mechanism holds the lid of the carrier.
Preferably, the carrier holding means may have carrier positioning means for positioning the carrier in such a manner that the carrier comes in sealing contact with the opening on the side of the atmospheric area.
Preferably, the carrier and the opening in the partition may be adapted to come in sealing contact with each other via a sealing element.
Preferably, the partition may have a second opening to communicate the atmospheric area with the inert gas area, and the unit further may comprise: a second door provided above the second opening to open and close it, second carrier holding means for holding a carrier of the substrate in such a manner that the carrier comes in contact with the second opening on the side of the atmospheric area, and second inert gas replacing means for replacing a gas in the carrier with an inert gas by introducing the inert gas into the carrier when the second door closes the second opening and the carrier comes in contact with the second opening on the side of the atmospheric area by the second carrier holding means.
Preferably, the door may be adapted to move downward to open the opening, and the second door is adapted to move upward to open the second opening.
REFERENCES:
patent: 5433574 (1995-07-01), Kawano et al.
patent: 5472086 (1995-12-01), Holliday et al.
patent: 5476176 (1995-12-01), Gregerson et al.
patent: 5562383 (1996-10-01), Iwai et al.
patent: 5575081 (1996-11-01), Ludwig
patent: 5607276 (1997-03-01), Muka et al.
patent: 5697749 (1997-12-01), Iwabuchi et al.
patent: 5810537 (1998-09-01), Briner et al.
patent: 5971696 (1999-10-01), Endo et al.
patent: 10321698 (1998-12-01), None
English Translation (Abstract Only) of Japanese Publication No. 10321698, Published Dec. 4, 1998.
Ishii Katsumi
Kikuchi Hisashi
Fischetti Joseph A.
Smith , Gambrell & Russell, LLP
Tokyo Electron
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