Container

Details Container Container

2001-07-28

2002-06-04

Bratlie, Steven A. (Department: 3652)

Material or article handling

Apparatus for moving material between zones having different...

C414S217100, C414S939000, C206S710000, C206S711000

Reexamination Certificate

active

06398475

ABSTRACT:

This application is the U.S. National Phase under 35 U.S.C. §371 of International Application PCT/JP98/05417, filed Dec. 2, 1998.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a container for receiving and transporting an article such as a substrate necessary to be kept under the condition of high cleanliness during being transported. It is described hereunder in relation to a semiconductor substrate such as a silicon wafer or a liquid crystal substrate, in particular a silicon wafer as an example, however, the present invention is not limited to the above. The present invention is applicable to any article necessary to be kept under the condition of high cleanliness during being transported.
2. Background of the Invention
The semiconductor substrate, in particular silicon wafer is contaminated when dust or vaporized organic compounds (hereinafter simply referred to as “dust”) are attached thereto, thus leading to a lower productivity, i.e., the rate of producing a high-quality of product is low. It is therefore necessary to maintain high cleanliness in surrounding environment of the silicon wafer when the silicon wafer is transported. More specifically, the silicon wafer is one of the articles necessary to be kept under the condition of high cleanliness during transported (hereinafter referred to as “dust free article”).
In general, the silicon wafer is worked in a room where cleanliness is high (hereinafter referred to as a “high cleanliness room”), i.e., so called a clean room. On the other hand, when the silicon wafer is transported in a room where cleanliness is low, the silicon wafer is received in a hermetically sealed container, the inside of which is kept under the condition of high cleanliness (hereinafter referred to as “container”), and then, the container with the silicon wafer received therein is transported. Thus, the silicon wafer can be transported through a room in which the degree of cleanliness is low or outdoor (hereinafter referred to as “low cleanliness room”), avoiding the silicon wafer from being contaminated during transported.
There is disposed a loader with an opening portion, which can be closed, in the border portion between the high cleanliness room and the low cleanliness room. The silicon wafer is transported through the above loader from the inner space of the container with high cleanliness to the high cleanliness room for working the silicon wafer or the like (hereinafter referred to as “loading”), in addition, from the high cleanliness room to the inner space of the container with high cleanliness for transferring the worked silicon wafer to an another treatment step (hereinafter referred to as “unloading”). More specifically, the silicon wafer is moved through the above opening portion, when loaded and unloaded. The container has a cover (i.e., lid) in a direction to the opening portion of the loader, which cover is opened when the silicon wafer is transferred into or out of the container.
When the silicon wafer is not transported, the opening portion of the loader is kept closed so as to prevent dust from floating into the high cleanliness room from the low cleanliness room. A door may be disposed in the opening portion so that the opening portion can be opened or closed by the door.
In this case, the door may be large enough to completely close the opening portion. In addition, the door may be the size in which the door is about 5 mm smaller in each side than respective side of the opening portion in such manner that there is provided aperture (open space) between the door and the opening portion, while the air pressure in the high cleanliness room is kept higher than that in the low cleanliness room, thus air flows through the aperture from the high cleanliness room to the low cleanliness room.
The following standards for the above container and loader are proposed and applied: SEMI (Semiconductor Equipment and Material International) Standard E47.1 [Box/Pod (FOUP)], E15.1[Tool Load Port], E57[Kinematic Coupling], E62[Front-Opening Interface Standard (FIMS), E63 [Box/Opener to Tool Standard (BOLTS) and the like (hereinafter referred to as “Standard”).
RELATED ART
The container with the dust free article received therein is transported in the low cleanliness room by hand or a robot. Then, the container is mounted on a loader disposed in the border portion between the high cleanliness room and the low cleanliness room by hand or a robot. The cover disposed in the frontal surface of the container is opened or closed by an opener mechanism installed in the loader, thus the opening portion of the container is connected to or shut off the high cleanliness room.
A positioning pin and a key are provided in the opener mechanism, and a positioning hole and a key hole are provided in the front side of the container. In opening the cover of the container, the positioning pin is inserted into the positioning hole, and then the key is inserted into the key hole, and then the key is turned so as to operate an lock mechanism installed in the cover of the container in such manner that a lock claw of the lock mechanism is released from a portion to be hooked which is disposed on an edge portion of the container in the opening portion. Then, the opener mechanism is relatively retreated while the positioning pin and the key are kept inserted, thus opening the cover.
However, the above-mentioned operation has not been successfully performed because the scale of the parts in the container vary slightly. More specifically, the opener mechanism which is made of metal and has mechanical construction, i.e., the positioning pin and the key has very small tolerance when manufactured (for example, ±0.01 mm), whereas the body or the cover of the container is made of resin and has a relatively large tolerance when manufactured (for example, at least ±0.5 mm).
Furthermore, since the material of the container has elasticity so as to cause the whole body of the container to be deflected downward, there exist the following problems:
A. The container is deflected against the metal base portion which is directly placed on the loader in such manner that the location of the positioning hole slightly varies to cause the positioning pin to fail to enter into the positioning hole.
B. Even though the positioning pin is successfully inserted into the positioning hole, the key fails to be entered into the key hole. The reason thereof is that the relative relationship of the positioning hole and the key hole changes slightly. More specifically, if the relative relationship thereof changes only 0.4 mm, the key is not successfully inserted into the key hole.
C. The cover which closes the opening portion of the container is dislocated and lowered by the weight thereof, thus further causing the problems described in items A an B above to occur.
In order to overcome the problem described in item A above, (1) the inner diameter of the positioning hole
65
is made larger than the outer diameter of the positioning pin
39
so as to provide a larger play E (refer to FIG.
13
). However, If the larger play E is provided, the cover is deflected downward by the same amount as the play E by the weight thereof, when the cover is opened. Accordingly, it is not easy to fittingly close the cover again.
Furthermore, in order to overcome the above-mentioned downward dislocation (i.e., downward movement) of the cover, there is proposed a technique in which a rubber cap
40
is provided around the positioning pin
39
so that the air inside the rubber cap
40
is sucked to be in a reduced pressure so as to support the cover
33
, thus preventing the cover from deflecting downward (refer to FIG.
2
). However, since the rubber cap
40
also has elasticity, the rubber cap does not satisfactorily function to support the cover.
In addition, in order to overcome the problem described in item A above, (2) chamfering is implemented on an edge of the positioning hole
65
, and the amount of play is reduced (refer t

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