Material or article handling – Apparatus for moving material between zones having different...
Utility Patent
1999-04-19
2001-01-02
Bratlie, Steven A. (Department: 3652)
Material or article handling
Apparatus for moving material between zones having different...
C414S940000
Utility Patent
active
06168364
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a vacuum clean box constructed such that objects to be transferred, necessary for fabrication processes of semiconductors, electron-device-associated products, optical disks, etc., can be transferred in a clean state with no contaminants and, particularly, the objects to be transferred are carried through a side aperture into or out of the box. Also, the present invention relates to a clean transfer method and apparatus using this vacuum clean box.
2. Related Background Art
Transfer boxes using the mechanical seal as illustrated in
FIG. 6
have been used heretofore for transferring semiconductor wafers or the like.
The assignee of the present invention suggested a clean transfer method for transferring the objects to be transferred, in a vacuum clean box in a vacuum sealed state in Japanese Laid-open Patent Application No. 7-235580.
FIG. 5
shows an example of the vacuum clean box used in this case.
The vacuum clean box
1
illustrated in
FIG. 5
is composed of a box body
2
and a bottom lid
3
also serving as a shutter for hermetic sealing, and a closed state thereof is maintained such that the bottom lid
3
is urged against the box body by a pressure difference between inside and outside the box (the inside of the box being a vacuum and the outside the atmospheric pressure). A holder
5
holds objects
4
to be transferred, for example, in a multiply stacked state on the bottom lid
3
. This vacuum clean box
1
is structured to open and close the bottom surface.
For opening the bottom lid
3
of the vacuum clean box
1
, the vacuum clean box
1
is mounted on a connection block
12
with an open/close aperture
11
of a vacuum changer
10
, which is indicated by fictitious lines in
FIG. 5
, the open/close aperture
11
is closed by an up-and-down type shutter
13
, and a hermetically closed space surrounded by the connection block
12
, the bottom lid
3
, and the up-and-down type shutter
13
is evacuated to cancel the pressure difference between inside and outside the bottom lid
3
. After that, the objects
4
on the bottom lid, together with the bottom lid
3
, are vertically lowered, as indicated by an arrow A, by a lid receiving up-and-down stage
14
on the vacuum changer
10
side to be drawn into the vacuum changer
10
and thereafter the objects
4
are horizontally transferred as indicated by an arrow B.
Incidentally, in the case of the vacuum clean box
1
of the bottom opening/closing type of
FIG. 5
, the vertical motion as indicated by the arrow A is essential to the operation of carrying the objects
4
into or out of the box. This involves change in the height of the objects
4
from the floor surface, so that the excess vertical motion is required, in addition to the horizontal motion for interface with various processing devices. In addition, since the vertical motion is necessary for carrying the objects
4
into or out of the box, there arises a problem that the placement height of the vacuum clean box
1
on the vacuum changer
10
also becomes high.
Meanwhile, standardization of the transfer boxes for semiconductors is under way in EIAJ (J300). The transfer boxes heretofore were of the type of taking the semiconductor wafers out of the bottom side of the box, but a laterally drawing method is being determined as a standardized method for the reason that the placement height of the box is high in the bottom opening/closing type. For example, the transfer box
20
for semiconductors of
FIG. 6
is also of the side open type having an aperture
21
in a side surface. This box, however, still leaves us the following challenges because of the mechanical seal; (1) a complex mechanism is necessary and sufficient reliability cannot be assured; (2) holding power sufficient for practical use cannot be obtained because of utilization of the mechanical holding power of springs or the like.
SUMMARY OF THE INVENTION
A first object of the present invention is, in view of the above points, to provide a vacuum clean box that does not have to use the conventional mechanical seal with the springs or the like even in the structure of the side open type, by employing a configuration in which a side lid can hermetically close a side aperture by a pressure difference between inside and outside thereof, and that has simple structure.
A second object of the present invention is to provide a clean transfer method and apparatus capable of transferring the objects to be transferred in the vacuum sealed state, using the vacuum clean box of the side open type in the simple structure without use of the mechanical seal.
The other objects and novel features of the present invention will become apparent in the description of embodiments hereinafter.
For accomplishing the above objects, a clean box of the present invention comprises a box body having an. aperture in one side surface and a small hole for intake/exhaust in another surface; a side lid for hermetically closing said aperture by a pressure difference between inside and outside thereof; and an additional lid for hermetically closing said small hole for intake/exhaust by a pressure difference between inside and outside thereof.
A clean transfer method of the present invention is a clean transfer method using a vacuum clean box comprising a box body having an aperture in one side surface and a small hole for intake/exhaust in another surface; a side lid for hermetically closing said aperture by a pressure difference between inside and outside thereof; and an additional lid for hermetically closing said small hole for intake/exhaust by a pressure difference between inside and outside thereof,
said clean transfer method comprising hermetically connecting said vacuum clean box to a gate aperture of a clean device, said gate aperture being formed in a side wall surface of said clean device and being hermetically closed by a gate valve; evacuating a hermetically closed space outside the box body, including said additional lid, by a vacuum changer to cancel the pressure difference between inside and outside of said additional lid and opening said small hole for intake/exhaust to turn the inside of said vacuum clean box into the atmospheric pressure through said small hole for intake/exhaust; thereafter drawing the side lid into said clean device while holding said side lid by said gate valve to establish communication between an inside space of said vacuum clean box and the inside of said clean device; and transferring objects to be transferred between said clean box and said clean device.
Further, a clean transfer apparatus of the present invention is a clean transfer apparatus comprising:
a vacuum clean box comprising a box body having an aperture in one side surface and a small hole for intake/exhaust in another surface; a side lid for hermetically closing said aperture by a pressure difference between inside and outside thereof; and an additional lid for hermetically closing said small hole for intake/exhaust by a pressure difference between inside and outside thereof;
a clean device having a gate aperture formed in a side wall surface thereof and a gate valve capable of opening or closing said gate aperture and capable of holding the side lid of the vacuum clean box connected to the gate aperture; and
a vacuum changer for evacuating a hermetically closed space outside the box body, including the additional lid of the vacuum clean box connected to said gate aperture,
wherein in a state in which said vacuum changer cancels the pressure difference between inside and outside of said additional lid and opens said small hole for intake/exhaust to turn the inside of said vacuum clean box into the atmospheric pressure through said small hole for intake/exhaust, said side lid is drawn into said clean device while being held by said gate valve, to establish communication between an inside space of said vacuum clean box and the inside of said vacuum clean device.
The clean transfer apparatus may also be so constructed that said vacuum changer has
Bratlie Steven A.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
TDK Corporation
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