Fluent material handling – with receiver or receiver coacting mea – Combined
Reexamination Certificate
1999-04-19
2001-03-13
Jacyna, J. Casimer (Department: 3751)
Fluent material handling, with receiver or receiver coacting mea
Combined
C141S063000, C141S348000, C220S212000, C220S240000, C215S270000
Reexamination Certificate
active
06199604
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a clean box constructed in such structure that objects to be transferred, necessary for production processes of semiconductors, electron-device-associated products, optical disks, etc., can be transferred in a sealed state with a clean gas containing no contaminants and, particularly, in such structure that the objects to be transferred can be transferred or stored in a sealed state with a non-oxidizing gas such as nitrogen gas, an inert gas, or the like so as to prevent oxidation of the objects to be transferred, and also relates to a clean transfer method and apparatus using the clean box.
2. Related Background Art
In general, the clean boxes of this type are arranged to have a box body having an aperture in one surface and an opening/closing lid for hermetically closing the aperture and include those using a mechanical seal with springs or the like for holding the opening/closing lid or those having the structure for vacuum suction of the opening/closing lid with higher adhesion, as described in Japanese Laid-open Patent Application No. 10-321696 (laid open on Dec. 4, 1998) of the invention invented by the same inventor and assigned to the same assignee as the present invention, than in the case of the mechanical seal using the springs or the like.
In use of such clean boxes, it was the conventional practice to put the objects to be transferred, such as semiconductor wafers or the like, in the clean box under the atmospheric pressure in a state filled with the clean air and prevent dust and various fine particles from attaching onto the objects to be transferred by hermetically closing the inside by the opening/closing lid.
Incidentally, with recent decrease in design rules of semiconductors to 0.25 &mgr;m or less, the thickness of film has to be controlled in the angstrom order. Particularly, there occurs a phenomenon that an unintended oxide film is naturally formed on a semiconductor wafer when it is exposed only to the atmosphere in the clean box and it becomes hard to control the film thickness in steps thereafter.
For preventing this, there was a technology in which nitrogen gas is introduced into the hermetically closed space while discharging the gas inside the hermetically closed space to the outside, thereby gradually decreasing the concentration of oxygen, but there was no conventional suggestion about a configuration for replacing the gas inside the clean box with nitrogen while maintaining good hermetic sealing.
SUMMARY OF THE INVENTION
A first object of the present invention is, in view of the above points, to provide a clean box having such structure that an inside space thereof can be replaced readily with a non-oxidizing gas such as nitrogen, an inert gas, or the like and permitting transfer or storage of the objects to be transferred, in a sealed state with the non-oxidizing gas.
A second object of the present invention is to provide a clean transfer method and apparatus permitting transfer of the objects to be transferred, in the sealed state with the non-oxidizing gas, using the clean box having such structure that the inside space thereof can be replaced readily with the non-oxidizing gas such as nitrogen, the inert gas, or the like.
The other objects and novel features of the present invention will become apparent in the description of embodiment hereinafter.
For accomplishing the above objects, a clean box of the present invention comprises a box body having an aperture in one surface, an opening/closing lid for hermetically closing the aperture, and a gas inlet valve and a gas outlet valve provided in the box body.
The clean box may be so constructed that the gas inlet valve and gas outlet valve have the same structure and each of the valves comprises a valve body urged in such a direction as to close a small aperture for inlet/exhaust of gas, and a filter for removal of dust disposed in a gas intake/exhaust passage running from the small aperture to an inside space of the box body.
A clean transfer method of the present invention is a clean transfer method using a clean box comprising a box body having an aperture in one surface, an opening/closing lid for hermetically closing the aperture, and a gas inlet valve and a gas outlet valve provided in the box body, the clean transfer method comprising steps of opening the gas inlet valve and gas outlet valve by a gas feeding/discharging mechanism in a state in which the aperture of said box body is closed by the opening/closing lid, introducing a non-oxidizing gas through the gas inlet valve into the clean box, and discharging a gas having filled the clean box before the introducing step of the non-oxidizing gas, through the gas outlet valve from the clean box.
Further, a clean transfer apparatus of the present invention is a clean transfer apparatus comprising:
a clean box comprising a box body having an aperture in one surface, an opening/closing lid for hermetically closing the aperture, and a gas inlet valve and a gas outlet valve provided in the box body; and
a gas feeding/discharging mechanism for opening the gas inlet valve and gas outlet valve in a state in which the aperture of the box body is closed by the opening/closing lid, introducing a non-oxidizing gas through the gas inlet valve into the clean box, and discharging a gas having filled the clean box before the introduction of the non-oxidizing gas, through the gas outlet valve from the clean box.
The clean transfer apparatus may be so constructed that the gas inlet valve and gas outlet valve have the same structure and each of the valves comprises a valve body urged in such a direction as to close a small aperture for intake/exhaust of gas, and a filter for removal of dust disposed in a gas intake/exhaust passage running from the small aperture to an inside space of the box body,
and that the gas feeding/discharging mechanism has intake/exhaust passages in communication with the respective small apertures for intake/exhaust of gas and actuating pins, each being arranged to push the valve body so as to open the small aperture.
Since the present invention presents the clean box in the structure comprising the box body having the aperture in one surface, the opening/closing lid for hermetically closing the aperture, and the gas inlet valve and gas outlet valve provided in the box body, the inside space can be replaced readily with the non-oxidizing gas such as the nitrogen gas, the inert gas, or the like in a perfect, hermetically closed state using the gas inlet valve and gas outlet valve, and the replacement operation can be automated. When each of the gas inlet valve and gas outlet valve is provided with the filter for removal of dust, the dust and other fine particles can be prevented from entering the clean box.
The clean box according to the present invention has neither evacuation means itself, such as a pump, for evacuating the inside of the box, nor transfer means for transferring the box.
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patent: 10-321696 (1998-12-01), None
patent: 10-321695 (1998-12-01), None
Jacyna J. Casimer
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
TDK Corporation
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