Material or article handling – Process – Of moving material between zones having different pressures...
Reexamination Certificate
2003-06-23
2004-09-28
Keenan, James W. (Department: 3652)
Material or article handling
Process
Of moving material between zones having different pressures...
C414S217100
Reexamination Certificate
active
06796763
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to transfer, under a clean environment, of various articles to be processed such as a semiconductor wafer in a manufacturing process of a semiconductor, an electronic part related product, an optical disk or the like, and more particularly to a clean box that makes it possible to transfer the articles among various processing devices in a clean condition without any contaminated substance, a clean transfer method and a clean transfer system using such a clean box.
2. Related Background Art
Recently, in a manufacturing process that needs a high level clean environment such as a semiconductor device manufacturing process, a method such as a mini-environment or a local clean space for keeping only the peripheral environment of a product under a clean condition without making the entire factory into a clean room state has been employed. Simply stating, this means that only an interior of each processing device in the manufacturing process is kept under a clean environment, and the transfer and the deposit of the articles to be processed is performed among the respective processing devices (clean devices) by using containers whose interior is kept clean (which will be referred to as clean boxes).
An example of such a local clean space system in the semiconductor manufacturing process will now be described with reference to
FIG. 1
that illustrates an embodiment of the present invention.
FIG. 1
shows a condition that a clean box
40
is mounted on a semiconductor wafer processing apparatus
10
as the local clean space (i.e., clean device).
The semiconductor wafer processing apparatus
10
is composed of an apparatus body
30
and a load port
20
for loading into the apparatus from the outside of the apparatus a semiconductor wafer that is an article to be processed by the apparatus body
30
.
FIG. 1
shows the apparatus body
30
on the left side and the load port on the right side of a straight line A. These load port
20
and the apparatus body
30
make the local clean space within the semiconductor wafer processing apparatus
10
together.
In such a local clean space system, in order to transfer the semiconductor wafer while keeping the clean condition among different processing devices, the clean box as a container whose interior is kept clean is used.
FIG. 1
shows a condition that the bottom open type clean box
40
is mounted on the load port
20
. The clean box
40
is composed of a box body
41
and a lid
42
. The lid
42
is removed downwardly and the wafer in the interior is taken out to be loaded on the processing device under the condition that the clean box
40
is laid on the load port
20
.
In the conventional clean box, the fixture of the lid to the box body has been carried out by a mechanical lock mechanism. For instance, a lock mechanism provided on the lid member and composed of a movable claw made of metal and a rotary cam member for moving the movable claw between a lock position where the movable claw projects by a predetermined amount from the outer periphery of the lid and a release position where the movable claw is retracted from the outer periphery of the of the lid, is used. In the case where the lid is to be fixed to the box body, the rotary cam member is rotated to thereby bring the movable claw to the lock position and the movable claw is engaged with a hole formed in the box body in this position so that the lid is locked to the box body. Such a lock mechanism of the clean box is operated by causing the above-described cam member to rotate by an opening/closing device provided in the load port under the condition that the clean box is mounted on the load port, to thereby perform the locking/releasing operation of the lid to/from the box body.
In order to keep the interior of the clean box clean, it is necessary to keep a sealed condition against the outside. Accordingly, a sealing means such as an O-ring for sealing the interface between the lid and the box body is provided. However, the above-described mechanical lock mechanism that has been used in the conventional clean box may impart a pressure of only several N's (Newton) at the largest so that the O-ring is not sufficiently deformed. For this reason, it is impossible to prevent dust or any other organic or inorganic substance from entering the interior, and it is impossible to maintain the clean space.
Also, in order to prevent the natural oxidation of the semiconductor wafer during the process waiting period, the interior air within the clean box is replaced with non-oxidizing gas such as nitrogen N
2
and inert gas, in some cases. However, the sealing force is small in the conventional mechanical lid lock mechanism, and therefore it is impossible to maintain the replacement condition of the non-oxidizing gas.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a bottom removal type clean box that is high in sealing property in comparison with a mechanical lock mechanism, and a transfer method and system using such a clean box.
In order to attain the above-mentioned object, a clean box according to a first aspect of the present invention has a structure comprising: a box body having an opening in a bottom; a lid member for closing the opening; an annular groove formed so as to surround the opening on at least one of the box body and the lid member to define a suction space sealed between the lid member and the box body under the condition that the lid member is mounted on the box body; and an intake/exhaust port for allowing vacuum exhaust/release of the annular groove from the outside.
The above-described annular groove may be formed on either box body side or lid member side or on both sides. In any case, in order to apply the present invention to a practical case, it is preferable that the periphery of the opening of the box body is in the form of a flanged shape and the annular groove is formed on the flange or on a portion of the lid member confronting the flange of the box body. In order to effect sealing, a sealing member such as an O-ring is provided along the groove. The clean box according to another aspect of the present invention to be described later also has the same structure with respect to the annular groove.
In this clean box, provision of the mechanical latch for preventing the lid member from falling apart from the box body is preferable, since even if the vacuum suction is damaged due to some reason during the transfer of the box, there is no fear that the lid member falls down. It is preferable that the mechanical latch has a mechanism for opening/closing the latch from the outside.
Also, as described above, if the semiconductor wafer is exposed in the air, an oxide film is naturally grown. This is undesirable. In order to prevent this, the gas within the clean box is replaced with the non-oxidizing gas such as nitrogen or inert gas. In accordance with this, a valve may be provided in the clean box according to the present invention for allowing the gas to be discharged or introduced for the replacement of the gas within the interior of the clean box.
It is preferable that the valve for replacement of gas in the interior of the clean box is composed of a gas input valve having a valve body for introducing the non-oxidizing gas into the interior of the clean box and a gas output valve having a valve body for discharging the gas in the clean box to the outside.
In a preferred mode of the clean box according to the present invention, an annular groove intake/exhaust port and the valves for gas replacement (gas input valve and gas output valve) are provided on the same single side surface of the clean box body. Thus, since the access directions for the vacuum discharge of the above-described annular groove and the various arrangements for replacement of the gas in the clean box, provided on the load port of a clean device such as a semiconductor wafer processing apparatus which receives clean box become the same, it is possible to simplify the structure of
Miyajima Toshihiko
Okabe Tsutomu
Keenan James W.
TDK Corporation
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