U.S. patent application number 12/683803 was filed with the patent office on 2010-05-06 for clean device with clean box-opening/closing device.
This patent application is currently assigned to TDK CORPORATION. Invention is credited to SHIGEKI ISHIYAMA, TOSHIHIKO MIYAJIMA.
Application Number | 20100108564 12/683803 |
Document ID | / |
Family ID | 33455473 |
Filed Date | 2010-05-06 |
United States Patent
Application |
20100108564 |
Kind Code |
A1 |
MIYAJIMA; TOSHIHIKO ; et
al. |
May 6, 2010 |
CLEAN DEVICE WITH CLEAN BOX-OPENING/CLOSING DEVICE
Abstract
In a load port portion of a conventional clean device, it can
happen that cleanliness is reduced by dust caused by wear of
bellows and a lid is not separated by its weight from a main body.
In order to solve such problems, a clean device is structured as
follows: a lid of a clean box has a non-circular reception hole, a
load port portion of the clean device has an opening/closing
mechanism with a projection fittable in the receiving hole and has
a buffer chamber, one end of bellows of the buffer chamber is
connected to the bottom surface of the buffer chamber, and the
other end of the bellows is fixed, on the outside of the buffer
chamber, to raising/lowering means of a port door.
Inventors: |
MIYAJIMA; TOSHIHIKO;
(Chuo-ku, JP) ; ISHIYAMA; SHIGEKI; (Chuo-ku,
JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND MAIER & NEUSTADT, L.L.P.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
TDK CORPORATION
Tokyo
JP
|
Family ID: |
33455473 |
Appl. No.: |
12/683803 |
Filed: |
January 7, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10556723 |
Nov 16, 2006 |
7674083 |
|
|
PCT/JP04/06604 |
May 11, 2004 |
|
|
|
12683803 |
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Current U.S.
Class: |
206/710 |
Current CPC
Class: |
H01L 21/67751 20130101;
Y10S 414/14 20130101; H01L 21/67126 20130101; H01L 21/67772
20130101 |
Class at
Publication: |
206/710 |
International
Class: |
H01L 21/673 20060101
H01L021/673; B65D 85/86 20060101 B65D085/86 |
Foreign Application Data
Date |
Code |
Application Number |
May 15, 2003 |
JP |
2003-137026 |
May 30, 2003 |
JP |
2003-154078 |
Claims
1. A clean device comprising: a lid and a main body having in a
vertically lower portion thereof an opening that is closed by the
lid, the clean device having an inside environment kept cleaner
than an outside environment to receive a substrate from a clean
box, which is kept highly clean inside and has the substrate stored
in the inside, and process the substrate; a load port portion
equipped with an opening/closing mechanism having a turnable latch
pin to separate the lid from the main body or couple the lid to the
main body with the clean box laid thereon; wherein: the lid of the
clean box has: a cam plate configured to engage with the latch pin
and actuating in accordance with a turning movement of the latch
pin; and a latch member protruding to an outside of the lid to
engage a latch hole of the main body of the clean box or being
confined within the lid to be released from the latch hole of the
main body of the clean box in accordance with an actuation of the
cam plate; the lid of the clean box further comprises a
non-circular receiving hole; the opening/closing mechanism further
comprises a protrusion that can be fittingly inserted into the
receiving hole; the latch pin becomes configured to engage the cam
plate and the protrusion of the opening/closing mechanism is
fittingly inserted into the lid of the clean box when the clean box
is laid on the load port portion; and the protrusion and the
receiving hole become configured to engage with each other in
accordance with a turning movement of the latch pin.
2. A clean device according to claim 1, wherein: the protrusion
comprises a brim portion at a tip thereof; and the opening/closing
mechanism is coupled to the lid through engagement of the brim
portion with a seat of the receiving hole after the protrusion is
inserted into the receiving hole.
3. A clean device according to claim 2, wherein: the brim portion
has a cross-sectional area that is smaller than and substantially
similar in shape to the receiving hole so that the brim portion can
be fittingly inserted into the receiving hole; the protrusion
further comprises a root portion smaller in cross-sectional area
than the brim portion; and the opening/closing mechanism and the
lid are coupled to each other through engagement between the brim
portion and the seat of the receiving hole resulting from rotation
of the root portion after the protrusion is inserted from the brim
portion into the receiving hole.
4. A clean device according to claim 2, wherein: the brim portion
has a cross-sectional area that is smaller than and substantially
similar in shape to the receiving hole so that the brim portion can
be fittingly inserted into the receiving hole; the protrusion
further comprises a root portion smaller in cross-sectional area
than the brim portion; the brim portion and the seat of the
receiving hole have faces spaced apart from each other by a
predetermined distance when the protrusion is inserted from the
brim portion into the receiving hole to a predetermined position;
and the brim portion and the seat of the receiving hole engage each
other when the protrusion is moved by the predetermined distance by
rotating the root portion.
5. A clean device according to claim 3, wherein: the root portion
is rotated while the latch member is rotated.
6. A clean device according to claim 1, wherein the load port
portion comprises: a port door that is raised and lowered and has
one face on which the lid is laid; a buffer chamber defined by wall
surfaces arranged surrounding an outer periphery of the port door
in a region where the port door is raised and lowered, and by a
bottom face arranged opposed to the other face of the port door;
raising/lowering means joined to the port door, for raising and
lowering the port door along a direction perpendicular to a face of
the port door; and a bellows arranged along an outer periphery of
the raising/lowering means; wherein the bellows is coupled at one
end thereof to the bottom face of the buffer chamber; and the
bellows is fixed at the other end thereof to the raising/lowering
means outside the buffer chamber.
7. A clean device according to claim 4, wherein: the root portion
is rotated while the latch member is rotated.
Description
CROSS REFERENCE
[0001] This application is a division of and is based upon and
claims the benefit of priority under 35 U.S.C. .sctn.120 for U.S.
Ser. No. 10/556,723, filed Nov. 16, 2006, the entire contents of
each which are incorporated herein by reference, which is a
National Stage of PCT/JP04/06604, filed May 11, 2004, and claims
the benefit of priority under 35 U.S.C. .sctn.119 from Japanese
Patent Application No. 2003-137026, filed May 15, 2003, and
Japanese Patent Application No. 2003-154078, filed May 30,
2003.
TECHNICAL FIELD
[0002] The present invention relates to an opening/closing
mechanism for opening and closing a lid of an SMIF-type clean box,
and to a load port portion of a clean device having the
opening/closing mechanism in a substrate processing device, in
which a substrate, such as a substrate of a semiconductor product
or the like as an object for a processing requiring high
cleanliness, is accommodated in the clean box and sealed up by its
lid and main body so as to ensure high cleanliness inside. The
substrate processing device loads/unloads the substrate into/from
the clean box. In loading and unloading the substrate, the lid is
vertically moved to be opened and closed.
[0003] The present invention also relates to an article
accommodating container for accommodating an article to be
processed in a highly clean environment such as a semiconductor, a
panel for a flat panel display, or an optical disk, and various
articles used together with that article, during a manufacturing
process thereof. More specifically, the present invention also
relates to the structure of a main body of the article
accommodating container having an opening portion located at
vertical side and to the structure of a lid for closing the opening
portion.
BACKGROUND ART
[0004] The processing of a substrate of a semiconductor product or
the like needs to be carried out in an environment in which high
cleanliness is ensured. In general, the processing is carried out
in a clean room that is entirely kept highly clean. However, heavy
investment in facilities and immense expenses of maintenance are
required in order to keep the entire room having a large cubic
volume highly clean. Even after an investment in facilities has
been made, further heavy investment in facilities would be needed
in changing the layout of the room associated with a change in
manufacturing process, which is not economical.
[0005] Further, substrates such as silicon wafers have been
increasing in size, so such a measure is problematic in terms of
the cost to ensure a required clean environment.
[0006] In view of the above, a method as disclosed in the
specification of Japanese Patent No. 3167970 has been known in
recent years, according to which the inside of a substrate
processing device (hereinafter referred to as a clean device) for
processing a substrate such as a semiconductor is kept highly clean
as a micro environmental space (hereinafter referred to as a
mini-environment portion), instead of keeping the entire room
highly clean, thereby achieving the same effect as in the case
where the entire room is kept highly clean.
[0007] That is, the substrate processing device is laid out in a
room where substrates are manufactured, and a substrate storing
container (hereinafter referred to as a clean box) whose inside is
kept highly clean is used to transfer substrates into and from the
clean device. Then, the clean box is coupled to a predetermined
substrate gateway provided in the substrate processing device so as
to prevent the entrance of dust from the outside. If substrates are
transferred via the predetermined gateway, the entire environment
to which those substrates are exposed can be kept highly clean
without enhancing the cleanliness of the room where those
substrates are manufactured. Thus, the same effect as in the case
where the entire room is turned into a clean room can be achieved.
As a result, an efficient production process can be realized by
cutting down on the amount of investment in facilities and the
expense of maintenance. In this specification, a substrate should
be construed to include, for example, an exposure mask (reticle), a
semiconductor wafer. Therefore, a substrate processing device
should be construed to include a reticle processing device and a
semiconductor wafer processing device.
[0008] A pod having an opening portion in a vertically lower side
as described above and adapted to open and close the opening
portion by vertically moving a lid is generically referred to as a
standard mechanical interface (SMIF) type pod. The present
invention relates to this SMIF type pod. As described above, an
efficient production process is realized while reducing the amount
of investment in facilities and the expense of maintenance and
achieving the same effect as in the case where an entire plant is
turned into a clean room, by adopting a so-called mini-environment
method in which only limited space is kept highly clean.
[0009] A clean device 1 will be described with reference to FIG. 9.
FIG. 9 is a view showing a cross-section of the entire clean device
1. The clean device 1 is provided with a processing room 60, a
transfer room 50, and a load port portion 10.
[0010] Various substrate processings to be carried out in the clean
device 1 are carried out in the processing room 60.
[0011] The transfer room 50 has therein a sealed-up space shut off
from the outside. A robot arm 55 for transferring substrates is
arranged in the transfer room 50.
[0012] A clean box 2 is laid on the load port portion 10 to
transfer substrates into the processing room 60 of the clean device
1. The load port portion 10 has a function of removing a lid 2b
from a main body 2a of the clean box 2.
[0013] A port door 3 that is substantially horizontally held is
arranged in the load port portion 10. The port door 3 is raised and
lowered vertically (see, Japanese Patent Application Laid-open No.
2001-203253). Referring to FIG. 9, the port door 3 is in its
lowered state. The port door 3 is surrounded by wall surfaces
surrounding the port door 3 on all four sides and a bottom portion
located substantially parallel to a lower face of the port door 3.
The wall surfaces and the bottom portion constitute a buffer
chamber 6 inside the load port portion 10. The buffer chamber 6 is
open at its top, thus constituting an access opening 5 that is
substantially equal in size to the port door 3. Therefore, when
viewed from the access opening 5, there is formed the buffer
chamber 6 having a predetermined depth. The size of the access
opening 5 is substantially equal to or smaller than that of an
envelope region of an opening of the clean box 2. The port door 3
is raised and lowered along the wall surfaces of the buffer chamber
6. The access opening 5 is covered with the main body 2a of the
clean box 2 as shown in FIG. 9 when the clean box 2 is laid on the
load port portion 10. The buffer chamber 6 of the load port portion
10 remains sealed up even when the lid 2b is removed.
[0014] In this example, a pod 2 accommodates, instead of a
substrate, a photomask called a reticle used in a semiconductor
processing process. The inside of the pod 2 is filled with a gas
such as dry nitrogen which is usually kept highly clean, when an
article is accommodated therein. Using this gas, the pressure
inside the pod 2 is thus held equal to or higher than an
atmospheric pressure to thereby reduce the possible internal
contamination resulting from an ambient environment.
[0015] The buffer chamber 6 in the load port portion 10 and an
inside 50a of the transfer room 50 communicate with each other
through a transfer opening 51. The inside 50a of the transfer room
50 and an inside 60a of the processing room 60 communicate with
each other through a transfer opening 52. The inside of the load
port portion 10, the inside 50a of the transfer room 50, and the
inside of the processing room 60 are sealed up to be shut off from
the external environment, thus forming a mini-environment
portion.
[0016] Further, the transfer opening 51 is opened and closed by an
opening/closing door 53 driven by an opening/closing gate valve
53a. On the other hand, the transfer opening 52 is opened and
closed by an opening/closing door 54 driven by an opening/closing
gate valve 54a.
[0017] Referring now to FIG. 10, the load port portion 10 will be
described in detail. FIG. 10 is a view showing the load port
portion 10 of FIG. 9 on an especially enlarged scale. As shown in
FIG. 10, the port door 3 is in its raised state unlike in the case
of FIG. 9. Referring to FIG. 10, the lid 2b is laid on the port
door 3. Note that, the port door 3 in its lowered state is
indicated by a chain double-dashed line in FIG. 10.
Raising/lowering means 4 is connected to the port door 3. The
raising/lowering means 4 is provided with a latch opening/closing
shaft 4a, a frame 4b for holding an actuator within the latch
opening/closing shaft, a raising/lowering shaft 4c, and an electric
actuator 7. The latch opening/closing shaft 4a is a vertically
extending rod-like member that is joined at one end thereof to the
lower face as an inner face of the port door 3, thus serving to
directly transmit a raising/lowering movement of the
raising/lowering means 4 to the port door 3. The latch
opening/closing shaft 4a is joined at the other end thereof, which
is located on the side opposite to the port door 3, to the frame
4b. The frame 4b is connected to the raising/lowering shaft 4c. The
raising/lowering shaft 4c is connected to the electric actuator 7.
Thus, the raising/lowering means 4 causes a raising/lowering
movement of the port door 3. A through-hole through which the latch
opening/closing shaft 4a extends is arranged at a lower center of
the buffer chamber 6. The size of the through-hole is substantially
equal to or smaller than that of the latch opening/closing shaft
4a.
[0018] A rotary shaft 33 rotatable around a center of the latch
opening/closing shaft 4a is mounted therein. Rod-like latch pins 32
arranged so as to protrude vertically from the surface of the port
door 3 are arranged at a tip of the rotary shaft 33. The latch pins
32 are arranged at arbitrary positions on a circumference of a
circle spreading around a rotation axis of the rotary shaft 33. It
is preferable that the latch pins 32 be circular holes arranged
point-symmetrically on the circumference of the circle.
[0019] The port door 3 is a rectangular flat plate substantially
corresponding in shape to the access opening 5. When being raised,
the port door 3 is fittingly inserted into the access opening 5 and
closes it as shown in FIG. 10, thus sealing up the buffer chamber 6
and shutting it off from the external world. A positioning pin 3c
as a protrusion, which protrudes from a top face of the port door 3
substantially perpendicularly thereto, is arranged on the top face
side of the port door 3 corresponding to the outer face side of the
load port portion 10 so as to position the lid 2b of the clean box
2. A hole corresponding to the positioning pin 3c extends through
the lid 2b of the clean box 2. When the clean box 2 is laid on the
load port portion 10 and the port door 3 is raised to abut on the
lid 2b of the clean box 2, the positioning pin 3c is fittingly
inserted into the hole so that the lid 2b is located at a right
position with respect to the port door 3.
[0020] A lower portion of the port door 3 constitutes a flange-like
brim 3a that is larger than the access opening 5. A sealing member
3b is fitted in the brim 3a. When the electric actuator 7 is driven
to raise the latch opening/closing shaft 4a to thereby fittingly
insert the port door 3 into the access opening 5, the brim 3a comes
into abutment with an edge portion 5a of the access opening 5,
thereby sealing up the buffer chamber 6. On the other hand,
conversely, when the electric actuator 7 is driven to lower the
latch opening/closing shaft 4a to thereby lower the port door 3,
the access opening 5 opens widely.
[0021] A bellows 31 is so fitted as to range from a lower face of
the port door 3 to at least an outer periphery of the latch
opening/closing shaft 4a in the buffer chamber 6 (e.g., see
Japanese Patent Application Laid-open No. 2001-203253 or Japanese
Patent Application Laid-open No. 06-268046). When the electric
actuator 7 is driven to raise the latch opening/closing shaft 4a,
the bellows 31 expands because the port door 3 moves away from the
bottom face. When the electric actuator 7 is driven to lower the
latch opening/closing shaft 4a, the bellows 31 contracts because
the port door 3 moves toward the bottom face.
[0022] A measure against falloff of the lid 2b from the main body
2a of the clean box 2 during transfer is taken by means of a latch
mechanism. FIG. 11 shows a latch mechanism inside the lid 2b.
[0023] A conventional latch mechanism typically has the following
structure. A rotatably arranged circular rotary cam plate 21 is
rotatably located substantially at a central position of the lid
2b. Latch holes 21a located at arbitrary positions on a
circumference of a circle spreading around a center of the rotary
cam plate 21 are formed therethrough. Note that the latch holes 21a
are preferably circular holes arranged point-symmetrically on the
circumference of the circle. The latch pins 32 engage the latch
holes 21a. The latch holes 21a are shaped so as to receive the
latch pins 32 therein, and are so arranged as to correspond in
position to the latch pins 32.
[0024] Arranged outside the latch holes 21a of the rotary cam plate
21 are two cam grooves 23, which are point-symmetrical to each
other with respect to the center of the rotary cam plate 21. Given
that each of the cam grooves 23 has one end as a starting point 23a
and the other end as an end point 23b, the distance between the
starting point 23a of the cam groove 23 and the center of the
rotary cam plate 21 is the shortest, whereas the distance between
the center of the cam groove 23 on the end point 23b side of the
cam groove 23 and the center of the rotary cam plate 21 is the
longest. On the other hand, the lid 2b has a latch member 26
movable parallel to the plane of the lid 2b. A driven pin 24 is
arranged on the rotary cam plate 21 side of the latch member 26.
The driven pin 24 is engaged with the cam groove 23. The latch
member 26 includes a tip portion protruding from a lateral face of
the lid 2b.
[0025] Now, when the latch pins 32 arranged at the tip of the
rotary shaft 33 in the latch opening/closing shaft 4 of the port
door 3 on which the lid 2b is laid are fittingly inserted into the
latch holes 21a and the rotary cam plate 21 is rotated by rotating
the rotary shaft 33, the driven pin 24 of the latch pin 26 moves
along the cam groove 23b from its starting point 23a toward its end
point 23b. In accordance therewith, the position of the driven pin
24 moves from the center of the rotary cam plate 21 toward the
outside thereof. In accordance with a moving distance of the driven
pin 24, a tip portion 22a of the latch member 26 moves toward the
outside of the lid 2b. The latch member 26 is set to be confined
within the lid 2b when the driven pin 24 is located at the starting
point 23a, and to protrude from the lid 2b when the driven pin 24
is located at the end point 23b. On the other hand, a latch hole 30
for engagement with the latch member 26a is arranged at the
position where the latch hole 30 abuts on the lid 2b for the main
body 2a of the clean box 2, so the lid 2b can be fixed to the clean
box 2 by rotating the rotary cam plate 21.
[0026] The rotatable latch pins 32 for engaging the cam grooves 23
of the rotary cam plate 21 are arranged as an opening/closing
mechanism on the top face of the port door 3. The latch pins 32 are
coupled to the rotary shaft 33 arranged within the latch
opening/closing shaft 4a. The rotary shaft 33 is coupled to a
rotary actuator 34 as rotation means.
[0027] Next, how a substrate 9 is exchanged between the load
portion 10, the transfer room 50, and the processing room 60 in the
clean device 1 will be described.
[0028] The clean box 2 is first laid on the load port portion and
fixed as shown in FIG. 9. At this moment, the substrate 9 is laid
on the lid 2b. When the latch opening/closing shaft 4a is raised by
driving the electric actuator 7, the port door 3 is raised while
the bellows 31 expands, and the latch pins 32 protruding from the
top face of the port door 3 are fittingly inserted into the latch
holes 21a. Then, the port door 3 comes into abutment with the lid
2b of the clean box 2. When the rotary actuator 34 is rotated at
this stage, the rotary shaft 33 rotates. In response thereto, the
latch pins 32 press the edges of the latch holes 21a, thus causing
the rotary cam plate 21 to rotate. When the rotary cam plate 21
rotates, the driven pin 24 rotates and the latch member 26 is
confined within the door 2b. In this state, the lid 2b fixed to the
main body 2a of the clean box 2 is then released therefrom.
[0029] When the electric actuator 7 is then driven to lower the
latch opening/closing shaft 4a, the port door 3 is also lowered
while the bellows 31 contracts. The lid 2b moves due to its own
weight away from the main body 2a of the clean box 2 as the port
door 3 is lowered. After the port door 3 has been completely
lowered, the lid 2b on which the substrate 9 is laid is located on
a bottom portion of the buffer chamber 6. In this state, the robot
arm 55 can then perform a transfer operation.
[0030] The buffer chamber 6 in the load port portion 10 and the
inside 50a of the transfer room 50 communicate with each other
through the transfer opening 51, and the inside 50a of the transfer
room 50 and the inside 60a of the processing room 60 communicate
with each other through the transfer opening 52. The inside of the
load port portion 10, the inside 50a of the transfer room 50, and
the inside of the processing room 60 are sealed up and shut off
from the external environment, thus forming a mini-environment
portion.
[0031] When the opening/closing gate valve 53a is driven to open
the opening/closing door 53, the buffer chamber 6 in the load port
portion 10 and the inside 50a of the transfer room 50 communicate
with each other. The substrate 9 is transferred from the buffer
chamber 6 in the load port portion 10 by operating the robot arm
55. Furthermore, the inside 50a of the transfer room 50 and the
inside 60a of the processing room 60 communicate with each other by
driving the opening/closing gate valve 54a to open the
opening/closing door 54. The substrate 9 is transferred from the
transfer room 50 into the processing room 60 by operating the robot
arm 55.
[0032] Note that included in related art documents about the
above-described constructions are Japanese Patent No. 3084827 and
Japanese Patent No. 2960540 as well as the aforementioned Japanese
Patent Application Laid-open No. 2001-203253 and Japanese Patent
Application Laid-open No. 06-268046.
[0033] In an SMIF type container, a latch member arranged on a lid
or a tip portion of the latch member engages a hole or a groove
formed in a main body of a pod, so that the lid is fixed to the
main body of the pod. That is, this fixation is accomplished when
the latch member comes into contact with a latch member receiving
face formed on the main body, and a load toward a central portion
of the lid and a load toward the main body are applied from the
latch member receiving face to the latch member. In this case, as
described in Japanese Patent No. 3167970 as well, a physical "rub"
occurs between the surface of the latch member and the latch member
receiving face so as to obtain the aforementioned loads, which may
result in generation of particles. As far as a single operation is
concerned, such particles are generated with very low frequency.
However, in a working process consisting of several tens of steps
or more, a considerable amount of particles may be generated.
[0034] In order to reduce the factors for generation of such
particles, according to the aforementioned Japanese Patent No.
2960540, two cam faces acting in different directions are provided
for a latch member. That is, a latch tip portion moves without
coming into contact with a latch receiving face in advancing or
retreating with respect to an inside of a main body portion such as
a groove. The latch tip portion moves substantially perpendicularly
to the latch receiving face in the process of engagement.
Therefore, in the construction disclosed in the above document, the
latch tip portion and the latch receiving face seldom rub each
other. Accordingly, with this construction, it seems possible to
suppress the generation of particles resulting from the rubbing of
the latch tip portion which has been conventionally deemed
problematic. However, the latch tip portion usually operates as a
fulcrum for pressing the entire lid against the main body portion.
Therefore, as is the case with the foregoing construction, loads
tend to converge on a contact point when this contact point is
obtained by a movement of the latch tip portion in the direction
substantially perpendicular to the latch receiving portion. As a
result of the convergence of the loads, there may occur a serious
local abrasion. In this case, the generation of particles due to a
cause slightly different from those of conventional cases seems to
raise a problem.
[0035] Note that, the pressure inside a pod and the pressure inside
a buffer chamber in a load port are generally held equal to or
higher than an atmospheric pressure by means of a clean gas. Thus,
even when the aforementioned particles and the like are generated,
they hardly enter the inside of the pod or the like. Thus, even
with the construction disclosed in Japanese Patent No. 2960540, it
is possible to achieve an effect of reducing the amount of
particles to some extent. However, in the case of an SIMF type
container used for a specific purpose such as accommodation of a
reticle, the inside of a pod is usually maintained in a
depressurized state, and an operation of taking out the reticle as
an accommodated article is also performed with the inside of a
buffer chamber depressurized. In this case, generated particles are
extremely likely to enter the inside of the pod or the like.
[0036] In consideration of the foregoing circumstances, there is
known a construction in which a vacuum space is formed on a lid
face on a main body side instead of employing a latch mechanism and
the atmospheric pressure applied to the lid due to the existence of
the vacuum space is used to ensure tight contact between the lid
and the main body and seal up of an inner space. This construction
eliminates the necessity of a latch mechanism, so it is absolutely
unnecessary to consider the generation of particles resulting from
the mechanism. In this construction, the lid is unlikely to fall
off even when the pressure in the vacuum space has become equal to
the atmospheric pressure for some reason, as long as the
construction is applied to a container having an opening in its
lateral face, such as a so-called FOUP. It is also relatively easy
to cope with such a situation. However, a vacuum break in the space
can cause the lid to fall off when the above-described construction
is applied to a container having an opening in its vertically lower
face, such as an SMIF type pod, so it is desirable to take an
appropriate measure. In this case, when the above-mentioned latch
mechanism is employed as a corresponding measure, the amount of the
aforementioned particles needs to be reduced as well.
DISCLOSURE OF INVENTION
[0037] As described above, the conventional clean device 1 has the
following problems.
[0038] (1) Although the opening/closing mechanism arranged on the
port door 3 of the load port portion 10 in the conventional clean
device 1 releases the latch mechanism serving as a device for
fixing the lid 2b, it simply holds the lid 2b itself and does not
forcibly remove the lid 2b from the main body 2a of the clean box 2
while keeping the lid 2b fixed to the port door 3. The lid 2b is
supposed to move spontaneously, due to its own weight away from the
main body 2a of the clean box 2.
[0039] This is because of the following reasons. Usually, the
internal pressure of the clean box 2 is substantially equal to the
atmospheric pressure, even in the state in which the inside of the
clean box 2 is filled with an inactive gas. Also, the lid 2b
itself, including the substrate 9, is heavy enough to move
spontaneously away from the clean box 2a owing to the gravity.
[0040] However, in the case of processing a substrate, in
particular a reticle, the entire clean device 1 including the
processing room 60 and the transfer room 50 needs to be kept not
only highly clean but also vacuum. In addition, the inside of the
clean box 2 also needs to be kept vacuum. In such a case, the
weight of the lid 2b may not allow the lid 2b to move away from the
main body 2a of the clean box 2. Further, as the sealing effect of
a sealing material arranged at a joint between the main body 2a and
the lid 2b of the clean box 2 for maintaining a vacuum state
increases, the tightness of contact between the sealing member and
the clean box 2 improves and the lid 2b becomes more unlikely to
fall off the clean box 2. This tendency is noticeable particularly,
for example, in the case where the substrate 9 is not laid.
[0041] (2) In the load port portion 10 in the conventional clean
device 1, the bellows 31 is mounted in the buffer chamber 6 between
the lower face of the port door 3 and the bottom portion of the
buffer chamber 6. The buffer chamber 6 is evacuated when the port
door 3 is lowered. However, abrasion of the bellows 31 resulting
from its expansion/contraction produces dust, which causes a
problem of a decrease in the degree of cleanliness in the buffer
chamber 6.
[0042] To solve the above-mentioned problems, the present invention
provides a clean device including a lid and a main body and having
an inside environment kept cleaner than an outside environment to
receive a substrate from a clean box, which is kept highly clean
inside and has the substrate stored in the inside, and process the
substrate, characterized in that: the clean device includes a load
port portion equipped with an opening/closing mechanism having a
turnable latch pin to separate the lid from the main body or couple
the lid to the main body with the clean box laid thereon; the lid
of the clean box has: a cam plate capable of engaging with the
latch pin and actuating in accordance with a turning movement of
the latch pin; and a latch member protruding to an outside of the
lid to engage a latch hole of the main body of the clean box or
being confined within the lid to be released from the latch hole of
the main body of the clean box in accordance with an actuation of
the cam plate; the lid of the clean box further includes a
non-circular receiving hole; the opening/closing mechanism further
includes a protrusion that can be fittingly inserted into the
receiving hole; the latch pin becomes capable of engaging the cam
plate and the protrusion of the opening/closing mechanism is
fittingly inserted into the lid of the clean box when the clean box
is laid on the load port; and the protrusion and the receiving hole
become capable of engaging with each other in accordance with a
turning movement of the latch pin. This makes it possible for the
port door to fix the lid in the clean device. Thus, the lid can be
positively moved away from the main body of the clean box not
solely due to the weight of the lid itself.
[0043] Further, to solve the above-mentioned problems, the present
invention provides a clean device including a lid and a main body
and having an inside environment kept cleaner than an outside
environment to receive a substrate from a clean box, which is kept
highly clean inside and has the substrate stored in the inside, and
process the substrate, characterized in that: the clean device
includes a load port portion for separating the lid from the main
body or coupling the lid to the main body with the clean box laid
thereon, to receive the substrate from the clean box; the load port
portion includes: a port door that is raised and lowered and has
one face on which the lid is laid; a buffer chamber defined by wall
surfaces arranged surrounding an outer periphery of the port door
in a region where the port door is raised and lowered, and by a
bottom face arranged opposed to the other face of the port door;
raising/lowering means joined to the port door, for raising and
lowering the port door along a direction perpendicular to the face
of the port door; and a bellows arranged along an outer periphery
of the raising/lowering means; the bellows is coupled at one end
thereof to the bottom face of the buffer chamber; and the bellows
is fixed at the other end thereof to the raising/lowering means
outside the buffer chamber. That is, the port door can be raised
and lowered in the clean box without producing dust.
[0044] Further, the present invention also provides a method in
which a clean device including a lid and a main body and having an
inside environment kept cleaner than an outside environment to
receive a substrate from a clean box, which is kept highly clean
inside and has the substrate stored in the inside, and process the
substrate, is used to separate the lid from the main body of the
clean box to prepare for extraction of the substrate, characterized
in that: the clean device includes a load port portion equipped
with an opening/closing mechanism having a turnable latch pin to
separate the lid from the main body or couple the lid to the main
body with the clean box laid thereon; the load port portion
includes: a port door capable of being raised and lowered and
having one face on which the lid is laid with an outer face of the
lid being in contact with the one face; and a buffer chamber
defined by wall surfaces arranged surrounding an outer periphery of
the port door in a region where the port door is raised and
lowered, and by a bottom face arranged opposed to the other face of
the port door; the lid of the clean box has: a cam plate capable of
engaging with the latch pin and actuating in accordance with a
turning movement of the latch pin; and a latch member protruding to
an outside of the lid to engage a latch hole of the main body of
the clean box or being confined within the lid to be released from
the latch hole of the main body of the clean box in accordance with
an actuation of the cam plate; the lid of the clean box further
includes a non-circular receiving hole; the opening/closing
mechanism further includes a protrusion that can be fittingly
inserted into the receiving hole; the clean device includes a first
exhaust port arranged close to the port door in the buffer chamber
and a second exhaust port arranged apart from the first exhaust
port of the buffer chamber; and the method includes: making the
latch pin capable of engaging with the cam plate when the clean box
is laid on the load port, and fittingly inserting the protrusion of
the opening/closing mechanism into the lid of the clean box;
evacuating an interface portion where the port door and the lid are
joined to each other, from the first exhaust port; evacuating the
buffer chamber from the second exhaust port; and lowering the port
door and transferring the substrate into the buffer chamber. Owing
to this method, in a clean device whose internal environment is
kept cleaner than an external environment to receive a substrate
from a clean box so as to process the substrate, the cleans device
having a lid and a main body, being kept highly clean inside, and
having the substrate stored in the inside, the substrate can be
taken out easily and reliably by separating the lid from the main
body of the clean box.
[0045] Further, to solve the above-mentioned problems, the present
invention provides a substrate processing device load port on which
a clean box including a main body and a lid, which is laid with a
substrate and fitted to the main body, is laid, for extracting the
substrate from an inside of the cleaning box, including: a port
door having an outer face on which the lid is laid; a buffer
chamber defined by wall surfaces arranged surrounding an outer
periphery of the port door, and by a bottom face arranged opposed
to an inner face of the port door; raising/lowering means joined to
the inner face of the port door, for raising and lowering the port
door along a direction perpendicular to the face of the port door;
and a bellows arranged along an outer periphery of the
raising/lowering means, the substrate processing device load port
being characterized in that: the bellows is coupled at one end
thereof to the bottom face of the buffer chamber; and the bellows
is fixed at the other end thereof to the raising/lowering means
outside the buffer chamber. That is, the port door can be raised
and lowered without producing dust.
[0046] Further, to solve the above-mentioned problems, the present
invention provides an opening/closing mechanism arranged in a
substrate processing device to extract a substrate from a clean box
and process the substrate by means of the substrate processing
device, the cleaning box having: a lid which has a cam plate and a
latch member that moves to protrude from the lid or to be confined
within the lid by means of the cam plate, and on which the
substrate can be laid; and a main body that is coupled to the lid
by means of a latch hole for receiving a tip of the latch member
when the latch member protrudes from the lid, characterized in
that: the opening/closing mechanism includes a rotatable latch pin
for engaging the cam plate; the lid further includes a non-circular
receiving hole; the opening/closing mechanism includes a protrusion
that can be fittingly inserted into the receiving hole; and the
opening/closing mechanism and the lid are coupled to each other
through engagement between the protrusion and the receiving hole to
remove the lid from the clean box. That is, the port door becomes
thereby capable of fixing the lid, so the lid can be positively
moved away from the main body of the clean box not solely due to
the weight of the lid itself.
[0047] Further, the present invention has been made in view of the
above-described circumstances, and it is an object of the present
invention to provide an article accommodating container for
accommodating an article such as a pod, for example, an SMIF type
pod, in which a lid is prevented from falling off etc. at the time
of a vacuum break and the generation of particles resulting from a
latch mechanism is suppressed. More specifically, it is an object
of the present invention to provide an article accommodating
container capable of suppressing the generation of particles
resulting from a latch mechanism and also preventing particles or
the like from entering the inside of the container when the
pressure in the container is lower than an atmospheric pressure
(i.e., when the inside of the container is depressurized).
[0048] To solve the above-mentioned problems, an article
accommodating container according to the present invention relates
to an article accommodating container including: a main body having
an inner space capable of accommodating an article and an opening
provided vertically below the inner space; and a lid for sealing
the inner space by closing the opening, characterized in that: the
main body and the lid have a depressurized space arranged
therebetween; the lid has a falloff preventing member capable of
protruding from an outer periphery of the lid; the main body has a
depressed portion for accommodating the falloff preventing member
without coming into contact with the falloff preventing member when
the falloff preventing member protrudes from the outer periphery of
the lid; and the falloff preventing member comes into contact with
an inner periphery of the depressed portion when a depressurized
state of the depressurized space for sealing the inner space by
means of the lid is broken with the falloff preventing member
protruding from the outer periphery of the lid.
[0049] In the aforementioned article accommodating container, it is
preferable that the depressurized space be either identical to or
different from the internal space. In the aforementioned article
accommodating container, it is preferable that the main body and
the lid have horizontally opposed first and second planes
respectively, and that the falloff preventing member protrude
horizontally from the second plane, and that the depressed portion
be formed in the first plane. It is preferable that the internal
space be circular or rectangular in its horizontal cross-section,
and that four corners of the internal space belong to an arc of a
circle having a predetermined radius.
BRIEF DESCRIPTION OF THE DRAWINGS
[0050] FIG. 1A is a side view of a load port portion of a clean
device according to the present invention.
[0051] FIG. 1B is a top view of the load port portion of the clean
device according to the present invention.
[0052] FIG. 2 is a view showing a lid of the clean box according to
the present invention.
[0053] FIG. 3A is a view showing a rotary cam plate of the lid of
the clean box according to the present invention.
[0054] FIG. 3B is a sectional view showing in detail a positional
relationship between the rotary cam plate of the lid of the clean
box according to the present invention and a port door of the load
port portion, taken along the line 3B-3B in FIG. 3A.
[0055] FIG. 4A is a view showing the rotary cam plate of the lid of
the clean box according to the present invention.
[0056] FIG. 4B is a sectional view showing in detail a positional
relationship between the rotary cam plate of the lid of the clean
box according to the present invention and the port door of the
load port portion, taken along the line 4B-4B in FIG. 4A.
[0057] FIG. 5A is a view showing the load port portion according to
the present invention with the port door in its lowered state.
[0058] FIG. 5B is a view showing the load port portion according to
the present invention with the port door in its raised state.
[0059] FIG. 6 is a flow chart showing a loading operation in the
load port portion according to the present invention.
[0060] FIG. 7 is a flow chart showing an unloading operation in the
load port portion according to the present invention.
[0061] FIG. 8A is a view showing a positional relationship of the
port door in the flow of the loading operation and the unloading
operation performed in the load port portion according to the
present invention.
[0062] FIG. 8B is a view showing a positional relationship of the
port door in the flow of the loading operation and the unloading
operation performed in the load port portion according to the
present invention.
[0063] FIG. 8C is a view showing a positional relationship of the
port door in the flow of the loading operation and the unloading
operation performed in the load port portion according to the
present invention.
[0064] FIG. 8D is a view showing a positional relationship of the
port door in the flow of the loading operation and the unloading
operation performed in the load port portion according to the
present invention.
[0065] FIG. 9 is a view showing a relationship between a load port
portion and an entire clean device according to a conventional art
and the present invention.
[0066] FIG. 10 is a view showing a load port portion of the
conventional art.
[0067] FIG. 11 is a view showing an example of a clean box of the
conventional art.
[0068] FIG. 12 is a view showing an example of a clean device in
the case where a common vacuum pump is employed.
[0069] FIG. 13 is a schematic sectional view showing a pod
according to another embodiment of the present invention.
[0070] FIG. 14 is a bottom view of a main body of the pod shown in
FIG. 13.
[0071] FIG. 15 is a bottom view showing the main body of the pod of
FIG. 13 with a lid fitted thereto, and further showing a part
relating to a falloff preventing mechanism formed inside the
lid.
[0072] FIG. 16A is an enlarged sectional view of a main part of a
pod according to still another embodiment of the present
invention.
[0073] FIG. 16B is an enlarged sectional view of a main part of a
pod according to still another embodiment of the present
invention.
BEST MODES FOR CARRYING OUT THE INVENTION
[0074] Referring to FIGS. 1A and 1B to FIG. 6, an embodiment of a
load port portion 10 of a clean device 1 of the present invention
will be described. FIG. 1A is an enlarged view of the load port
portion 10 of the present invention. The overall construction of
the load port portion 10 in the clean device 1 is the same as the
construction described as the conventional art referring to FIG. 9.
The clean device 1 and that of FIG. 9 have the following respects
in common. The clean device 1 is provided with a processing room
60, a transfer room 50, and the load port portion 10. A clean box 2
is laid on the load port portion 10 so as to transfer a substrate 9
into a semiconductor device. The load port portion 10 has a
function of removing a lid 2b from a main body 2a of the clean box
2. In other words, as is the case with the conventional clean
device 1, the load port portion 10 is connected to the transfer
room 50 via a transfer opening 51, and the load port portion 10 and
the transfer room 50 are separated from each other by an
opening/closing door 53. A substantially horizontally held port
door 3 is arranged within the load port portion 10.
[0075] The load port portion 10 has a buffer chamber 6, which is
surrounded by wall surfaces surrounding the port door 3 on all four
sides and a bottom portion located substantially parallel to a
lower face of the port door 3. As is the case with the conventional
device, the buffer chamber 6 is classified into two parts for the
sake of convenience. That is, one of the parts is an interface
space 6a on an upper face side of the port door, the other part is
the buffer chamber 6 on a lower face side of the port door 3.
[0076] The lower face of the port door 3 is connected to a latch
opening/closing shaft 4a arranged below the port door 3. The latch
opening/closing shaft 4a is arranged so as to extend outward and
downward through a hole arranged through a bottom face of the
buffer chamber 6. The latch opening/closing shaft 4a is connected
to an electric actuator 7 as raising/lowering means via a frame 4b.
The frame 4b is connected to the electric actuator to raise and
lower the latch opening/closing shaft 4a vertically. A rotary shaft
33 is arranged within the latch opening/closing shaft 4a in a
penetrating manner. Unlike the conventional device, the rotary
shaft 33 performs a raising/lowering operation as well as a
rotating operation. In order to perform the raising/lowering and
rotating operations, a rotary actuator 8a for rotating the rotary
shaft 33 and a raising/lowering cylinder 8b for raising/lowering
the rotary shaft 33 in the latch opening/closing shaft 4a are
arranged within the frame 4b. A substrate detecting sensor 77 is
arranged in the load port portion 10 so as to face the wall
surfaces surrounding the port door 3 on all four sides. The
substrate detecting sensor 77 is composed of emitters 77a for
radiating infrared rays from loopholes and detectors 77b for
receiving infrared rays emitted from the emitters. The emitters 77a
and the detectors 77b are arranged on opposed wall surfaces
respectively. FIG. 1B is a vertical top view of the load port
portion 10 shown in FIG. 1A, showing a positional relationship
between the emitters 77a and the detectors 77b. The substrate
detecting sensor 77 is not limited to an infrared sensor. As shown
in FIG. 1B, the emitters 77a and the detectors 77b are arranged
such that the substrate 9 crosses optical axes of rays emitted from
the emitters 77a and reaches the detectors 77b when the substrate 9
is raised and lowered. Therefore, if the optical axes are
interrupted at a position where the substrate 9 is supposed to
cross them when the port door 3 is raised or lowered, it turns out
that the substrate 9 is laid on the lid 2b.
[0077] Then, the following description will focus especially on
differences between the load port portion 10 of the present
invention and the conventional load port portion. The load port
portion 10 of the present invention and the conventional clean
device 1 mainly share the following two features.
[0078] The first feature is that coupling means is provided as an
opening/closing mechanism for coupling the port door 3 to the lid
2b of the clean box 2 to open and close the lid 2b. Owing to this
feature, the lid 2b can be forcibly removed from the main body 2a
of the clean box 2 without counting on the weight of the lid
2b.
[0079] The second feature is that, while in the conventional art
the bellows 31 is mounted in the buffer chamber 6 between the lower
face of the port door 3 and the bottom portion of the buffer
chamber 6, in the present invention, the bellows 31, which is
coupled at one end 31a thereof to the bottom face portion of the
buffer chamber 6 and fixed at the other end 31b thereof to the
raising/lowering means 4, is mounted outside the buffer chamber 6.
Thus, it is possible to suppress generation of dust in the buffer
chamber 6.
[0080] In this specification, the term "coupling" means that the
lid 2b is coupled so as to move in accordance with a
raising/lowering movement of the port door. Those features will be
described hereinafter.
[0081] (Coupling Means)
[0082] The port door 3 is provided with the opening/closing
mechanism of the present invention. The opening/closing mechanism
has coupling means for coupling the lid 2b of the clean box 2 and
the port door 3 to each other. Referring first to FIG. 2, the clean
box 2, especially the lid 2b of the clean box 2 will be described.
FIG. 2 is a top view showing an internal structure of the lid 2b of
the clean box 2. As is the case with the conventional rotary cam
plate 21, the lid 2b of the clean box 2 is mounted with a latch
mechanism. The latch mechanism includes a generally circular rotary
cam plate 21 arranged at the center of the lid 2b, and a latch
member 26. The rotary cam plate 21 is arranged substantially at the
center of the lid 2b of the conventional clean box 2 rotatably
around the center. Latch holes 21a arranged on a circle concentric
with the rotary cam plate 21 are defined in a central region of the
rotary cam plate 21.
[0083] Two cam grooves 23, which are point-symmetrical to each
other with respect to the center of the rotary cam plate 21, are
arranged outside the latch holes 21a of the rotary cam plate 21.
Given that each of the cam grooves 23 has one end as a starting
point 23a and the other end as an end point 23b, the distance
between the starting point 23a of the cam groove 23 and the center
of the rotary cam plate 21 is the shortest, whereas the distance
between the center of the cam groove 23 on the end point 23b side
of the cam groove 23 and the center of the rotary cam plate 21 is
the longest. Each of the cam grooves 23 has such a smooth arcuate
shape that the distance from the center of the cam plate 21
gradually changes from the starting point 23a to the end point 23b.
On the other hand, the lid 2b has the latch member 26 movable
parallel to a plane thereof. A driven pin 24 is arranged at an end
portion 26b of the latch member 26 on the rotary cam plate 21 side.
This driven pin 24 is in engagement with the cam groove 23. The
latch member 26 also includes a tip portion 26a protruding from a
lateral face of the lid 2a. The latch member 26 is slidably held
between a guide member 28a and a guide member 28b in such a manner
that the latch member 26 penetrates through guide holes formed
therein. The guide holes are substantially identical to the latch
member 26 in cross-sectional shape. A spring 27 is fitted between
the guide member 28a and the guide member 28b, urging the latch
member 26 to expand to the outside of the lid 2b. The setting of
the urging direction of the spring 27 can be modified as required
either to the direction in which the latch member 26 expands
outwardly or to a direction in which the latch member 26 contracts
inwardly. When the rotary cam plate 21 rotates, the cam groove 23
also rotates in response thereto, so the latch member 26 is
accommodated inside the lid 2b or protrudes outside the lid 2b. A
latch hole 30 is arranged through an edge of the main body 2a of
the clean box 2 abutting on the lid 2b, at a position corresponding
to the tip portion 26a of the latch member 26. When the latch
member 26 protrudes with the tip portion 26a protruding outside the
lid 2b, the tip portion 26 of the latch member 26 is received in
the latch hole 30 and engaged therewith, so the lid 2b is fixed to
the clean box 2. On the other hand, when the latch member 26 is
drawn furthest inside the lid 2b due to rotation of the rotary cam
plate 21, the tip portion 26a of the latch member 26 is
accommodated in the lid 2b, so the lid 2b is not coupled to the
clean box 2. The diameter of the latch hole 30 is sufficiently
larger than that of the latch member 26 received in the latch hole
30, thus preventing dust from being generated through sliding
friction between the latch hole 30 and the latch member 26. With
this construction as well, since the lid sticks to the clean box 2
in an attractive manner when the clean box 2 is a vacuum, there is
no possibility of the lid 2b falling off from the main body 2a of
the clean box 2.
[0084] The lid 2b and the port door 3 of the present invention are
coupled to each other and therefore equipped with coupling means
composed of what are called male-side coupling means and
female-side coupling means. It is optional which one of the
male-side coupling means and the female-side coupling means is
arranged on the lid 2b side. This embodiment will be described as a
representative example on the premise that the female-side coupling
means is arranged on the lid 2b side and the male-side coupling
means is arranged on the port door 3 side.
[0085] First of all, the female-side coupling means on the lid 2b
side will be described. A counter boring 42 and a receiving hole 41
as the female-side coupling means are arranged through a central
portion of the lid 2b. The receiving hole 41 is arranged so as to
extend through from the face of the lid 2b abutting on the port
door 3 to a bottom portion of the counter boring 42. The receiving
hole 41 typically assumes a non-circular shape. For instance, the
receiving hole 41 may assume a rectangular or elliptical shape. It
is appropriate that the counter boring 42 is larger in size than
the receiving hole 41, and that a bearing surface of the counter
boring 42 remains as a seat 41a of the receiving hole 41.
[0086] Then, the coupling means on the port door 3 side will be
described with reference to FIGS. 3A, 3B, 4A, and 4B. In this
state, namely, the latch opening/closing shaft 4a has been raised
and the port door 3 abuts on the lid 2b, as described above as to
the conventional art. Each of FIGS. 3A and 4A is an enlarged view
showing the rotary cam plate 21 portion when the port door 3 abuts
on the lid 2b. On the other hand, FIGS. 3B and 4B are sectional
views taken along a line 3B-3B of FIG. 3A and a line 4B-4B of FIG.
4A, respectively.
[0087] The male-side coupling means is arranged at a position
corresponding to the center of a rotary circular plate 21 at the
end portion of the rotary shaft 33 on the lid 2b side. A protrusion
45 as the male-side coupling means is equipped with a cylindrical
root portion 45b extending from an end face of the rotary shaft 33,
and a brim portion 45a arranged on a tip portion side of the root
portion 45b. The brim portion 45a achieves its effect if it is
larger in cross-sectional area than the root portion 45b. When a
projection plane of the brim portion 45a is viewed along a center
axis of the rotary shaft 33 from the lid 2b side toward the plane
of the port door 3, the projection plane of the brim portion 45a is
substantially similar in shape to and slightly smaller than a
through-hole 42 to the extent that the brim portion 45a can be
fittingly inserted into the receiving hole 41. When viewed from
that direction after having been further rotated, the brim portion
45a deviates in shape from the receiving hole 41, thus creating an
overlapping region. This overlapping region enables engagement with
the seat 41a of the receiving hole 41 as the bearing surface of the
counter boring 42. In this embodiment, the receiving hole 41 is a
substantially rectangular long hole, and the brim portion 45a has a
substantially rectangular shape allowing insertion into the
receiving hole 41 and is slightly smaller than it.
[0088] The rotary shaft 33 arranged inside the latch
opening/closing shaft 4a can be raised and lowered in such a manner
that the rotary shaft 33 slides along a central axis of a
raising/lowering shaft 3 within the latch opening/closing shaft 4a.
On the other hand, the latch pins 32 are arranged at the tip of the
latch opening/closing shaft 4a so as to protrude vertically from
the port door 3. The latch pins 32 are located at positions
corresponding to the latch holes 21a of the rotary cam plate 21 on
a circumference of a circle substantially concentric with the
rotary cam plate 21, and arranged point-symmetrically to each other
with respect to the center of the rotary cam plate 21.
[0089] In this case, when the rotary shaft 33 is raised within the
latch opening/closing shaft 4a as shown in, for example, FIG. 3B,
the brim portion 45a is fittingly inserted into the receiving hole
41, and the latch pins 32 are fittingly inserted into the latch
holes 21a. At this stage, the shapes of the brim portion 45a and
the receiving hole 41 projected onto the plane of the rotary cam
plate 21 are substantially identical to each other. When the rotary
shaft 33 is rotated at this stage, the projections of the brim
portion 45a and the receiving hole 41 onto the plane of the rotary
cam plate 21 are different in shape from each other as shown in
FIG. 4A and create overlapping regions, respectively. Those
overlapping regions correspond to the seat 41a of the receiving
hole 41. The port door 3 and the lid 2b can be coupled to each
other through mutual contact of the overlapping regions.
[0090] The fragile substrate 9 is laid on the lid 2b and thus may
be damaged when strong vibrations are transmitted to the lid 2b.
Thus, the brim portion 45a and the seat 41a of the receiving hole
41 do not engage each other when the rotary shaft 33 is rotated.
The projections of the brim portion 45a and the receiving hole 41
onto the rotary cam plate 21 are different in shape from each other
and create overlapping regions when the rotary shaft 33 is rotated.
The influence on the substrate 9 can be reduced by thereafter
lowering the rotary shaft 33 to bring the overlapping regions into
contact with each other. More specifically, the height between the
face of the seat 41a of the receiving hole 41 as the bearing
surface of the counter boring 42 and the face of the brim portion
45a contactable with the seat 41a (the lower face in this
embodiment) is set to a predetermined height (t) as a backlash. As
soon as this predetermined height (t) is ensured, the rotary shaft
33 is operated to be rotated and then moved downward. Then, as soon
as the rotary shaft 33 is lowered by the predetermined height (t),
the seat 41a of the receiving hole 41 as the bearing surface of the
counter boring 42 and the face of the brim portion 45a contactable
with the seat 41a engage each other, thus completing the process of
coupling.
[0091] If the rotary shaft 33 is set to become as high as the face
of the lid 2b when being raised to the highest position, the end
face 33a of the rotary shaft 33 and the face 3b of the port door 3
are substantially equal in height to each other, thus allowing
abutment on the face of the lid 2b. The latch pins 32 are fitted
into the latch holes 21a and turned by rotating the rotary shaft
33. The latch member 26 thereby moves with respect to the lid 2b,
thus making it possible to open the lid 2b from the main body 2a of
the clean box 2 and fix the lid 2b to the port door 3 at the same
time.
[0092] By combining the aforementioned coupling means with the
clean box 2 described with regard to the conventional art, it
becomes possible to realize an efficient step of simultaneously
performing the operation of fixing/releasing the lid 2b to/from the
port door 3 and the operation of coupling the lid 2b to the port
door 3. This step will be described with reference to FIGS. 2, 3A,
3B, 4A, and 4B.
[0093] In this case, a representative example in which the lid 2b
fixed to the main body 2a of the clean box 2 is released from the
main body 2a will be described. In fixing the lid 2b fixed to the
main body 2a of the clean box 2 to the main body 2a, the following
steps should be carried out in reverse order. At first, the port
door 3 is located at the highest position. The end face of the
latch opening/closing shaft 4a and the end face of the port door 3
are located at the same position. In this state, the clean box 2 is
laid on the load port portion 10. At this moment, the clean box 2
is laid such that the protrusion 45 is fittingly inserted into the
lid 2b and that the latch pins 32 are fittingly inserted into the
latch holes 21a. At this moment, the protrusion 45 and the latch
pins 32 are fittingly inserted into the receiving hole 41 and the
latch holes 21a, respectively. In this state, the latch member 26
protrudes from the lid 2b and is received in the latch hole 30
arranged through the lateral face of the clean box 2, so the lid 2b
is fixed to the clean box 2. When the rotary shaft 33 is rotated at
this stage, the latch pins 32 press the edges of the latch holes
21a to rotate the rotary cam plate 21. The driven pin 24 moves
along the cam groove 23 as the rotary cam plate 21 rotates. In
accordance with this movement of the driven pin 24, the latch
member 26a moves so as to be accommodated in the lid 2b and is
released from the latch hole 30 of the clean box 2. The brim
portion 45a of the protrusion 45 also rotates as the rotary cam
plate 21 rotates by being pressed by the latch pins 32. The brim
portion 45a and the receiving hole 41 are positioned so as to
create overlapping regions when viewed from the lid 2b side in the
direction of the plane of the port door 3 along the central axis of
the rotary shaft 33, such that the brim portion 45a can be engaged
with the seat 41a of the receiving hole 41. As a result, a
preparation for coupling is completed (which is referred to as an
unlock preparation completion state). Then, when the rotary shaft
33 is lowered by the height t as the backlash, the overlapping
regions of the projections of the brim portion 45a and the
receiving hole 41 abut on each other and engage each other to
couple the lid 2b to the port door 3, so the clean box 3 is also
fixed to the lid 2b (which is referred to as a hold-down
preparation completion state).
[0094] (Arrangement of Bellows)
[0095] Then, the bellows 31 of the present invention will be
described with reference to FIGS. 1A, 5A, and 5B.
[0096] The bellows 31 is tightly coupled at one end 31a thereof to
the bottom face outside the buffer chamber 6, and is fixed at the
other end 31b thereof to the frame 4b and the latch opening/closing
shaft 4a for performing raising/lowering operations by means of the
electric actuator outside the buffer chamber 6. Thus, the bellows
31 is always arranged outside the buffer chamber 6. If this
arrangement is adopted, the bellows 31 always performs its
expansion/contraction movements outside the buffer chamber 6 both
when the port door 3 is lowered as shown in FIG. 5A and when the
port door 3 is raised as shown in FIG. 5B. By adopting this
arrangement, the clearance between the bellows 31 and the latch
opening/closing shaft 4a located inside the bellows 31 as well as
the buffer chamber 6 can maintain vacuum even when the buffer
chamber 6 is evacuated through an exhaust port 58. Although
conventionally the bellows 31 generates dust in the buffer chamber
6, adoption of the arrangement of the present invention produces
effects unachievable by the conventional device. That is, (i) the
amount of dust can be limited to that of dust flowing into the
buffer chamber 6 from a clearance 31c between the inside of the
bellows 31 and the buffer chamber 6, and (ii) the bellows 31
usually falls downward due to the gravity and can be prevented from
rising.
[0097] Then, the operation of the load port portion 10 of the clean
device 1 of the present invention will be described with reference
to FIGS. 6, 7, and 8A to 8D.
[0098] First of all, a loading operation will be described with
reference to FIG. 6.
[0099] At first, the port door 3 is located in the load port
portion 10 with its load port having been raised to the highest
position (a state shown in FIG. 8A). At this stage, a robot (not
shown) or a transfer vehicle (not shown) arranged outside the clean
device 1 lays the clean box 2 on the port door 3 of the load port
portion 10 of the clean device 1. In this process, the latch pins
23 and the protrusion 45 are fitted into the latch holes 21a and
the receiving hole 41, respectively (S601). Then, the presence or
absence of the clean box 2 is confirmed by means of a clean box
presence/absence detecting sensor on the port door 3 (S602). Then,
the interface space 6a is evacuated by carrying out suction and
discharge using a first vacuum pump 72 connected to a first exhaust
port 81 arranged in the vicinity of the port door 3 that is in its
waiting state in the buffer chamber (S603). The interface space 6a
is theoretically an interface between the port door 3 and the lid
2b and practically a narrow clearance created between the port door
3 and the lid 2b when the port door 3 is in its raised state. Then,
a vacuum pressure of the interface space 6a is detected by an
interface pressure sensor 71 arranged in the vicinity of the
interface space 6a, and it is confirmed whether or not the detected
vacuum pressure has reached a predetermined pressure. When the
vacuum pressure has not reached the predetermined pressure, further
evacuation is carried out from the first exhaust port 81 using the
first vacuum pump 72 (S604). By making the interface space 6a
itself a vacuum, the port door 3 and the lid 2b stick to each
other. Subsequently, a vacuum pressure in the buffer chamber 6 is
detected by a buffer chamber pressure sensor 74, and it is
confirmed whether or not the detected vacuum pressure has reached a
predetermined pressure. When the detected vacuum pressure has not
reached the predetermined pressure, the buffer chamber 6 is
evacuated by performing suction and discharge from a second exhaust
port 82 arranged apart from the first exhaust port 81 at a position
most effective for discharge of the volume of the buffer chamber 6,
namely, at a position close to the center or bottom portion of the
buffer chamber 6, using a second vacuum pump 75 connected to the
second exhaust port 82 (S605). The rotary shaft 33 is rotated by
driving the rotary actuator 8a. Thus, the unlock preparation
completion state is achieved as described above (S606). The steps
described hitherto create the state shown in FIG. 8A.
[0100] Then, when the rotary shaft 33 is lowered by the
raising/lowering cylinder 8b, the hold-down preparation state is
achieved as described above (S607). The port door 3 is lowered by
drive means, so the lid 2b is separated from the main body 2a of
the clean box 2, lowered to a predetermined position, and then
stopped (S608). The substrate detecting sensor 77 in the buffer
chamber 6 detects the presence/absence of the substrate 9 on the
lid 2b (S609). The robot arm 55 in the transfer room 50 transfers
the substrate 9 to the processing room 60 (S610). The steps
described hitherto create a state shown in FIG. 8B.
[0101] First of all, an unloading operation will be described with
reference to FIG. 7. Basically, the loading operation is performed
in reverse order.
[0102] The robot arm 55 in the transfer room 50 fetches the
processed substrate 9 from the processing room 60 and lays it at a
predetermined position of the lid 2b on the port door 3 waiting in
the buffer chamber 6 of the load port portion 10 (S701). The
substrate detecting sensor 77 confirms whether or not the substrate
9 is appropriately laid on the port door (S702). A vacuum pressure
in the buffer chamber 6 is detected by the buffer chamber pressure
sensor 74, and it is confirmed whether or not the detected vacuum
pressure has reached a predetermined pressure. When the detected
vacuum pressure has not reached the predetermined pressure, further
evacuation is carried out from the second exhaust port 82 using the
second vacuum pump 75 (S703). It is confirmed whether or not the
rotary actuator 8a is in the unlock preparation completion state
and whether or not the raising/lowering cylinder 8b is in the
hold-down preparation state (S704). The electric actuator 7 raises
the port door 3 and closes the buffer chamber 6. In this state, the
lid 2b closes the main body 2a of the clean box 2. Then, when the
rotary shaft 33 is raised by the raising/lowering cylinder 8b, the
shape of the brim portion 45a and the receiving holes 41 are
disengaged from each other. When the rotary actuator 8a is driven
at this stage to rotate the rotary shaft 33, the latch member 26 of
the lid 2b is inserted into the latch hole 30 through rotation of
the rotary cam plate 21. The brim portion 45a becomes drawable from
the receiving hole 41 (S705). Subsequently, the vacuum interface
space 6a is charged with high-purity nitrogen gas from an N.sub.2
bomb 73 and purged of the nitrogen gas to be held again at the
atmospheric pressure. This is confirmed using the interface space
pressure sensor 71 (S706). This step is intended to prevent the
port door 3 and the lid 2b from remaining stuck to each other as in
the case where the interface space 6a is a vacuum. The robot (not
shown) or the transfer vehicle (not shown) transfers the clean box
2 out from the load port portion 10 of the clean device 1
(S707).
[0103] Although the foregoing embodiment has been described on the
premise that the first vacuum pump 72 and the second vacuum pump 75
are separate from each other, the first vacuum pump 72 and the
second vacuum pump 75 can be integrated into a single common vacuum
pump. In this case, the second vacuum pump 75 is employed as the
common vacuum pump instead of the first vacuum pump 72 as shown in,
for example, FIG. 12. In this embodiment, the second vacuum pump 75
which is the common vacuum pump is connected to a flow channel 85.
The flow channel 85 is connected to a first flow channel 83 leading
to the first exhaust port 81 and a second flow channel 84 leading
to the second exhaust port 82. The first flow channel 83 is
provided with a valve 87 for discharging gas from flow channels on
the first exhaust port 81 side by means of the vacuum pump. When
the valve 87 is opened, it is possible to suck/discharge gas
into/from the flow channels of a system on the first exhaust port
81 side including the first flow channel 83, and thus
suck/discharge gas into/from the interface space 6a. On the other
hand, the second flow channel 84 is provided with a valve 86 for
discharging gas from flow channels on the second exhaust port 82
side by means of the vacuum pump. When the valve 86 is opened, it
is possible to suck/discharge gas into/from the flow channels of a
system on the second exhaust port 82 side including the second flow
channel 84, and thus suck/discharge gas into/from the buffer
chamber 6. Thus, the same effect as in the foregoing embodiment in
which the first vacuum pump 72 and the second vacuum pump 75 are
separate from each other is achieved even when the single common
vacuum pump is employed.
[0104] The present invention achieves the following effect.
[0105] By coupling the port door of the load port portion to the
lid of the clean box and mounting the bellows outside the buffer
chamber, the lid and the main body of the clean box can be
coupled/decoupled to/from each other while the clean device is kept
highly clean.
[0106] Next, the construction of a pod according to still another
embodiment of the present invention will be described with
reference to the figures. FIG. 13 is a schematic sectional view of
an article accommodating container according to the present
invention, that is, a pod. FIG. 14 is a bottom view of a main body
of the pod with its lid having been removed. FIG. 15 is a bottom
view of the pod with its lid fitted thereto, partially showing an
internal structure thereof. In those figures, components performing
operations similar to those of the components described in the
conventional art will be described using the same reference symbols
as used in FIGS. 9 to 11. The load port and the like described in
the conventional art with reference to FIG. 10 are employed.
[0107] (Shape of Pod)
[0108] The pod 2 according to the present invention is composed of
the main body 2a and the lid 2b. The main body 2a has an outward
appearance of a generally cubic shape having a generally tubular
first inner space 111a and a generally cubic second inner space
111b formed therein. The first inner space 111a assumes a circular
shape or a generally rectangular shape whose four corners each are
formed of a part of a circular arc having an arbitrary diameter
when viewed from above. The second inner space 111b continues to
the first inner space 111a below the first inner space 111a. The
first inner space 111a has a size large enough to accommodate an
article to be held therein, in this case, the reticle (or
substrate) 9 having a contour indicated by a chain double-dashed
line in the figure. The main body 2a has on its lateral portion a
brim portion 112 used in transferring the pod. A circular window
portion 113 for observing an inner space, to which a glass or the
like is fixed to maintain airtightness of the inner space, is
arranged on the upper face of the main body 2a.
[0109] A plurality of work holding-down pins 114 extending downward
from above to restrict the vertical movement of the reticle are
arranged at equal intervals in the circumferential direction of the
reticle in the first inner space 111a. The work holding-down pins
114 are in contact at their protruding tip portions with the
reticle so as to reduce the area of contact with the reticle. Each
of the work holding-down pins 114 is fixed to the main body 2a via
a support member 114b so as to prevent an excessive load from being
applied to the reticle. The second inner space 111b has a size
large enough to accommodate the later-described lid 2b and groove
portions 115, which will be described later, formed in two opposed
lateral faces of the second inner space 111b.
[0110] A work guide 116 and work pins 117 are provided on the upper
face of the lid 2b, which is on the main body 2a side in closing
the main body 2a. The work guide 116 has a generally annular shape
allowing insertion through the first inner space 111a. A guide
portion 116a for guiding an outer periphery portion of the reticle
in the inner space on all four sides protrudes from an outer
periphery portion of an upper face of the work guide 116. The work
pins 117 are arranged so as to be substantially opposed to the
aforementioned work holding-down pins 114, and their tip portions
support the reticle. An O-ring 118 is arranged along an outer
periphery of the work guide 116 on the upper face of the lid 2b.
The O-ring 118 is in tight contact with a face 111c defining an
upper face of the second space 111b, so the first space 111a
defined by the main body 2a and the lid 2b is sealed up.
[0111] The pod 2 according to the present invention keeps the
pressure in the first space 111a lower than an ambient pressure
(atmospheric pressure), thereby holding the main body 2a and the
lid 2b while ensuring firm contact therebetween. In the pod 2, the
first space 111a maintained as a depressurized space has a
generally circular cross-sectional shape. As a result, the pod 2
becomes robust against a load resulting from the atmospheric
pressure even when there is a great difference between the pressure
in the space and the ambient pressure or when the cross-sectional
area of the inner space has increased. It is easy to form the pod 2
assuming this shape from a metal such as aluminum, and it is also
easy to subject an inner surface thereof to an electrolytic
polishing treatment. Generation of particles from the inner surface
of the pod or the like can be suppressed by performing the
treatment.
[0112] (Falloff Preventing Mechanism)
[0113] Next, a falloff preventing mechanism, which is a component
added to the pod according to the present invention as a
countermeasure against a case where the state of tight contact
between the main body 2a and the lid 2b is broken through a loss of
the depressurized state in the aforementioned first space 111a,
will be described in detail. A falloff preventing mechanism 120 for
preventing the lid 2b from falling off is arranged inside the lid
2b. The falloff preventing mechanism is composed of a cam plate 121
in the shape of a circular plate, falloff preventing plates 124,
and preventing plate holders 126. The cam plate 121 is turnably
arranged substantially at a central position of the lid 2b.
Engagement holes 121a arranged on arbitrary positions on a
circumference of a circle spreading around the center of the rotary
cam plate 121 are formed therethrough. It is preferable that the
engagement holes 121a are circular holes arranged
point-symmetrically on the circumference of the circle.
[0114] The engagement holes 121a, with which the latch pins 32 of
the load port portion 10 are engaged, are shaped so as to be able
to receive the latch pins 32 and arranged so as to correspond in
position to the latch pins 32. Two cam grooves 123 located
point-symmetrically with respect to the center of the cam plate 121
are arranged outside the engagement holes 121a of the cam plate
121. Given that each of the cam grooves 123 has one end as a
starting point 123a and the other end as an end point 123b, the
distance between the starting point 123a of the cam groove 123 and
the center of the cam plate 121 is the shortest, whereas the
distance between the center of the cam groove 123 on the end point
123b side of the cam groove 123 and the center of the cam plate 121
is the longest.
[0115] Each of the falloff preventing plates 124 is constructed of
a generally rod-like member extending on a line connecting the
center of the cam plate 121 to substantially central portions of
the groove portions 115 provided in the main body 2a. Each of the
preventing plate holders 126 is constructed of a plate-like member
extending parallel to the direction in which the falloff preventing
plates 124 extend. The preventing plate holders 126 are fixed to
the lid 2b and support the falloff preventing plates 124 via two
bushes 125 such that the falloff preventing plates 124 can be
driven in the direction in which they extend. Driven pins 127 are
fixed to end portions of the falloff preventing plates 124 on the
cam plate 121 side. The driven pins 127 are inserted into the cam
grooves 123 in a penetrating manner. Spring members 128 are
arranged around spaces between the two bushes 125 of the falloff
preventing plates 124. Stoppers 128a fixed to the falloff
preventing plates 124 restrict the movement of the spring members
128 in the direction in which the falloff preventing plates 124
extend. Owing to loads applied from the spring members 128 in the
direction in which the falloff preventing plates 124 extend, the
falloff preventing plates 124 are prevented from trembling at
respective positions along their movements and causing vibrations
or the like.
[0116] When the lid 2b is laid on the load port portion 10, the
latch pins 132 protruding above the surface of the port door 3 are
fittingly inserted into the latch holes 121a. When the rotary shaft
133 is rotated in this state, the cam plate 121 rotates together
with the latch pins 132, and each of the driven pins 127 at the end
of the falloff preventing plate 124 moves from the starting point
123a toward the end point 123b of a corresponding one of the cam
grooves 123. That is, the driven pins 124 move outward from the
center of the rotary cam plate 121, along the direction in which
the falloff preventing plates 124 extend. In accordance with the
movements of the driven pins 127, tip portions 124a of the falloff
preventing plates 124 move toward the outside of the lid 2b. The
tip portions 124a are set to be confined within the lid 2b when
each of the driven pins 127 is located at the cam groove starting
point 123a, and to protrude from the lid 2b when each of the driven
pins 127 is located at the cam groove end point 123b.
[0117] As described above, the groove portions 115 are formed at
the positions corresponding to the tip portions 124a of the falloff
preventing plates 124 in the main body 2a of the clean box 2. The
tip portions 124a are located within the groove portions 115 when
they protrude outside the lid 2b. The width, height, and depth of
the groove portions 115 are set such that the tip portions 124a do
not come into contact with any part in the inside of the groove
portions 115 in performing a normal operation. Accordingly, no
particles or the like are generated as a result of the falloff
preventing member according to the present invention, especially
the tip portions 124a of the falloff preventing plates 124. In
other words, only when the depressurized state of a space operating
to keep the main body 2a and the lid 2b in tight contact with each
other is broken, the falloff preventing member operates to prevent
the tip portions 124a and inner walls of the groove portions 115
from being substantially separated from each other through mutual
contact and engagement therebetween.
Modified Example
[0118] Next, a modified example of the pod according to another
embodiment of the present invention will be described.
[0119] Components achieving the same operations and effects as
those of the components described in the foregoing embodiment will
be described using the same reference symbols. Each of FIGS. 16A
and 16B is an enlarged sectional view showing an essential part of
the pod 2 in this embodiment. In this embodiment, the lid 2b is
kept in tight contact with the main body 2a not by depressurizing
the inner space 111a but by depressurizing a space 119 provided to
keep them in tight contact with each other. FIG. 16A shows a case
where the space 119 is formed in a region of the lid 2b opposed to
the face 111c. FIG. 16B shows a case where the space 119 is formed
in the face 111c. To seal up the space, O-rings 118 are arranged in
inner and outer peripheral portions of the space 119 having a
generally annular shape at such positions as to allow tight contact
with the face 111c.
[0120] By thus providing the dedicated space 119 operating to keep
the main body 2a and the lid 2b in tight contact with each other,
it becomes possible to hold the pressure in the first inner space
111a substantially equal to or higher than the atmospheric pressure
using, for example, dry nitrogen. The lid 2b can be prevented from
separating from the main body 2a due to the operation of the
falloff preventing mechanism even if the depressurized state of the
space 119 has been broken. Therefore, in comparison with the
conventional SMIF type pod, a reticle and the like can be held
inside under the condition of a wider pressure range. The present
invention also makes it possible to completely eliminate the
phenomena of engagement, abrasion, and the like of the latch member
and the like as is inevitably the case with the conventional SMIF
type pod. Thus, the amount of particles and the like generated at
the time when the main body 2a and the lid 2b are kept in tight
contact with each other can be reduced drastically.
[0121] In the foregoing embodiment, the tip portion of the falloff
preventing member is caused to protrude outside the lid 2b by
rotating the cam plate in the shape of a circular disc and
transmitting this rotational movement to the falloff preventing
member via a cam mechanism. However, various known mechanisms can
be employed as a drive mechanism for the falloff preventing member
as long as its tip portion can be driven reciprocally. In other
words, the falloff preventing member can adopt various
constructions as long as a part of the falloff preventing member
can protrude from the outer periphery portion of the lid when the
lid is in tight contact with the main body. The groove portions
provided on the main body 2a side to accommodate the tip portion of
the falloff preventing member are not limited in shape to those of
this embodiment either. The groove portions can assume various
shapes as long as an inner volume for preventing contact between
the tip portion of the falloff preventing member and inner
peripheral faces of the groove portions is ensured when the falloff
preventing member is normally driven. It is also appropriate to
arrange elastic members made of rubber or the like on the inner
peripheral faces to absorb an impact caused, for example, when the
lid falls off.
[0122] In this embodiment, the falloff preventing member protrudes
in such a direction that the falloff preventing member protrudes
between the horizontally opposed faces provided on the main body
and the lid, respectively, and the groove portions are provided in
those opposed faces. However, the embodiment of the present
invention is not limited to this construction. It is also
acceptable to adopt a construction in which the falloff preventing
member protrudes toward a face vertically opposed thereto, for
example, the face 111c and a protruding portion of the falloff
preventing member, after having protruded into a groove portion
provided in the face 111c, can be engaged with a part of the groove
portion. More specifically, a hook-like portion may be provided at
the tip of the protruding portion to be rotated within the groove
portion to allow engagement. Alternatively, the hook-like portion
may further protrude from the tip portion after having been
arranged within the groove portion.
[0123] According to the present invention, the depressurized space
formed inside the main body of the pod and the lid serves to ensure
tight contact therebetween. The falloff preventing mechanism for
preventing the lid from falling off usually does not perform
engagement accompanied with friction or the like with the main body
portion but comes into contact with a part of the main body portion
only when the depressurized state of the depressurized space is
broken. In addition, it is not absolutely required that the
depressurized space is the article accommodating space within the
pod. That is, the depressurized space may be formed for the sole
purpose of ensuring tight contact. By adopting this construction,
it becomes possible to drastically reduce the amount of particles
and the like generated as a result of the construction for actually
performing the operations of sealing and the like, in performing
the operation of sealing or opening the main body of the pod by
means of the lid.
[0124] Since the falloff preventing mechanism has been added, an
accident such as falloff of the lid separated from the main body
can be prevented even when the depressurized state of the
depressurized space has been broken. Moreover, the falloff
preventing mechanism according to the present invention can be
substantially composed of the same elements as those constituting a
so-called latch mechanism used in fixing the lid to the pod in the
conventional art, and can be directly applied to the conventional
load port or the like.
[0125] The main body of the pod according to the present invention
is structured such that the space for actually accommodating an
accommodated article such as a reticle has a generally circular
cross-sectional shape. Thus, the resistance against a differential
pressure between the outside and inside of the container is
enhanced, so the container can be used as a robust vacuum
container. It is easy to form the pod assuming this shape from a
metal, and it is possible to easily subject the inside thereof to a
treatment of suppressing generation of particles, such as an
electrolytic polishing treatment.
* * * * *