U.S. patent application number 10/849024 was filed with the patent office on 2004-12-02 for purge system for product container and interface seal used in the system.
This patent application is currently assigned to TDK CORPORATION. Invention is credited to Miyajima, Toshihiko, Suzuki, Hitoshi.
Application Number | 20040237244 10/849024 |
Document ID | / |
Family ID | 33455542 |
Filed Date | 2004-12-02 |
United States Patent
Application |
20040237244 |
Kind Code |
A1 |
Suzuki, Hitoshi ; et
al. |
December 2, 2004 |
Purge system for product container and interface seal used in the
system
Abstract
Disclosed is a sealing system for intake and exhaust ports used
when performing purging on the interior of a container
accommodating objects, such as an FOUP, wherein the sealing of the
intake and exhaust lines is effected in a satisfactory manner with
respect to the external environment. The sealing member has a
ring-shaped main body portion, an inner peripheral lip protruding
from the ring inner peripheral portion of the main body portion,
and an outer peripheral lip protruding from the ring outer
peripheral portion of the main body portion, wherein the space
formed by the inner peripheral lip, the outer peripheral lip, etc.
can be evacuated.
Inventors: |
Suzuki, Hitoshi; (Tokyo,
JP) ; Miyajima, Toshihiko; (Tokyo, JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
TDK CORPORATION
Tokyo
JP
103-8272
|
Family ID: |
33455542 |
Appl. No.: |
10/849024 |
Filed: |
May 20, 2004 |
Current U.S.
Class: |
15/301 |
Current CPC
Class: |
H01L 21/67126 20130101;
H01L 21/67393 20130101 |
Class at
Publication: |
015/301 |
International
Class: |
A47L 005/38 |
Foreign Application Data
Date |
Code |
Application Number |
May 26, 2003 |
JP |
2003-147643 |
May 26, 2003 |
JP |
2003-147653 |
Claims
What is claimed is:
1. A purge system for a product container in which a container-side
port formed in the product container and a stand-side port formed
in a stand on which the container is placed are substantially in
contact with each other via a sealing member, and a gas line for
performing at least one of gas supply and evacuation with respect
to an interior of the container is formed between the stand-side
port and the container-side port, wherein the sealing member has: a
ring-shaped main body portion to be fixed to an opening end portion
of a stand-side port opening so as to surround an outer periphery
of the stand-side port opening; a first lip portion substantially
extending from an inner peripheral portion of the ring-shaped main
body portion toward the other opening end portion different from
the opening end portion where the main body portion is fixed; a
second lip portion substantially extending from an outer peripheral
portion of the ring-shaped main body portion toward the other
opening end portion different from the opening end portion where
the main body portion is fixed; and a hole provided in the main
body portion between the first lip portion and the second lip
portion so as to extend to an end surface where the first lip
portion and the second lip portion are not formed, and wherein the
stand has a gas flow path communicating with the hole and connected
to an exhaust system.
2. A purge system for a product container according to claim 1,
wherein the first lip portion and the second lip portion are
adapted to be deformed in directions which are different from each
other and in which the first lip portion and the second lip portion
respectively extend, according to a pressure in a space insulated
from an ambient environment by the sealing member.
3. A purge system for a product container in which a container-side
port formed in the product container and a stand-side port formed
in a stand on which the container is placed are substantially in
contact with each other via a sealing member, and a gas line for
performing at least one of gas supply and evacuation with respect
to an interior of the container is formed between the stand-side
port and the container-side port, wherein the sealing member has: a
ring-shaped main body portion to be fixed to an opening end portion
of a container-side port opening so as to surround an outer
periphery of the opening; a first lip portion substantially
extending from an inner peripheral portion of the ring-shaped main
body portion toward the other opening end portion different from
the opening end portion where the main body portion is fixed; and a
second lip portion substantially extending from an outer peripheral
portion of the ring-shaped main body portion toward the other
opening end portion different from the opening end portion where
the main body portion is fixed, and wherein the stand has a gas
flow path which communicates with a portion formed between the
first lip portion and the second lip portion when the stand-side
port and the container-side port are held in contact with each
other and which is connected to an exhaust system.
4. A purge system for a product container according to claim 3,
wherein the first lip portion and the second lip portion are
adapted to be deformed in directions which are different from each
other and in which the first lip portion and the second lip portion
respectively extend, according to a pressure in a space insulated
from an ambient environment by the sealing member.
5. An interface seal device which, when connecting together a first
space and a second space which are insulated from an ambient
environment, which are capable of maintaining an internal pressure
different from a pressure of the ambient environment, and which
each have an opening, is arranged between an opening-forming
surface of the first space and an opening-forming surface of the
second space to thereby insulate the first space and the second
space from the ambient environment, comprising: a ring-shaped main
body portion to be fixed to one of the opening-forming surface of
the first space and the opening-forming surface of the second space
so as to surround an outer periphery of the opening; a first lip
portion substantially extending from an inner peripheral portion of
the ring-shaped main body portion toward the other opening-forming
surface different from the opening-forming surface where the main
body portion is fixed; and a second lip portion substantially
extending from an outer peripheral portion of the ring-shaped main
body portion toward the other opening-forming surface different
from the opening-forming surface where the main body portion is
fixed, wherein the first lip portion and the second lip portion are
adapted to be deformed in directions which are different from each
other and in which the first lip portion and the second lip portion
respectively extend, according to pressures in the first space and
the second space.
6. An interface seal device according to claim 5, wherein the main
body portion has a hole provided between the first lip portion and
the second lip portion so as to extend to an end surface where the
first lip portion and the second lip portion are not formed.
7. An interface seal device according to claim 5, wherein the first
lip portion has a configuration whose inner diameter gradually
diminishes as the first lip portion is departed from the main body
portion, and wherein the second lip portion has a configuration
whose inner diameter gradually increases as the second lip portion
is departed from the main body portion.
8. A sealing member which, when connecting together a first space
and a second space which are insulated from an ambient environment,
which are capable of maintaining an internal pressure different
from a pressure of the ambient environment, and which each have an
opening, is arranged between an opening-forming surface of the
first space and an opening-forming surface of the second space to
thereby insulate the first space and the second space from the
ambient environment, comprising: a ring-shaped main body portion to
be fixed to one of the opening-forming surface of the first space
and the opening-forming surface of the second space so as to
surround an outer periphery of the opening; a first lip portion
substantially extending from an inner peripheral portion of the
ring-shaped main body portion toward the other opening-forming
surface different from the opening-forming surface where the main
body portion is fixed; and a second lip portion substantially
extending from an outer peripheral portion of the ring-shaped main
body portion toward the other opening-forming surface different
from the opening-forming surface where the main body portion is
fixed, wherein the main body portion has a hole provided between
the first lip portion and the second lip portion so as to extend to
an end surface where the first lip portion and the second lip
portion are not formed.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a product container for
accommodating articles, such as semiconductors, panels for flat
panel displays, or optical disks, which are produced in a
high-cleanliness environment, during the production process
thereof, and to a so-called load port for opening and closing such
a product container. More specifically, the present invention
relates to a purge system for substituting a gas sealed in a
so-called FOUP (front-opening unified pod) accommodating articles
as mentioned above, mainly semiconductor wafers with a diameter of
300 mm during their treatment. Further, the present invention also
relates to a so-called interface seal (herein after referred to as
a sealing member) used to connect an FOUP (front-opening unified
pod) to a gas substitution system for substituting a gas sealed in
the FOUP.
[0003] 2. Related Background Art
[0004] Up to the present, in a semiconductor manufacturing process,
the requisite high cleanliness for the process has been achieved by
turning the plant for performing various treatments on wafers into
a cleanroom in its entirety. However, as wafers increase in
diameter, this method of obtaining a high-cleanliness environment
has come to involve a problem in terms of cost, and in recent
years, a system has come to be adopted in which a minienvironment
maintaining high cleanliness for each processing apparatus is
ensured.
[0005] More specifically, in this system, instead of enhancing the
cleanliness of the plant as a whole, high cleanliness is maintained
during the production device only in the interior of respective
processing apparatuses and in a storage container (hereinafter
referred to as a pod) during transport between the respective
processing apparatuses. As mentioned above, this pod is generally
referred to as an FOUP. By thus adopting the so-called
minienvironment system in which high cleanliness is achieved solely
in small spaces, it is possible to achieve the same effect as in
the case in which the entire plant is turned into a cleanroom, thus
achieving a reduction in equipment investment and maintenance cost
and realizing an efficient production process.
[0006] In the following, a semiconductor processing apparatus or
the like that is actually used and in conformity with the so-called
minienvironment system will be briefly described. FIG. 6 is a
general view of a semiconductor wafer processing apparatus 50. The
semiconductor wafer processing apparatus 50 is mainly composed of a
load port portion 51, a conveyance chamber 52, and a processing
chamber 59. These components are separated from each other by a
partition 55a and a cover 58a on the load port side and a partition
55b and a cover 58b on the process chamber side. In the conveyance
chamber 52 of the semiconductor wafer processing apparatus 50, an
airflow from above toward below is generated by a fan (not shown)
provided in the upper portion thereof in order to discharge dust to
maintain high cleanliness. Thus, dust is always discharged
downwardly.
[0007] The load port portion 51 has a pod 2 installed on a stand
53, the pod 2 serving as a storage container for products such as
silicon wafers (hereinafter simply referred to as wafers). As
stated above, high cleanliness is maintained in the interior of the
conveyance chamber 52 for processing of wafers 1, and, further, a
robot arm 54 is provided therein. By this robot arm 54, the wafers
are transferred between the interior of the pod 2 and the interior
of the processing chamber 59. Usually, the processing chamber 59
contains various mechanisms for performing various treatments on
the wafer surfaces, such as thin film formation and thin film
processing. However, since these components are not directly
related to the present invention, a description thereof will be
omitted.
[0008] The pod 2 has a space for containing the wafers 1
constituting the objects of treatment, and is equipped with a
box-shaped main body portion 2a having an opening in one surface
thereof and a cover 4 for tightly closing the opening. Inside the
main body portion 2a, there is arranged a shelf with a plurality of
stages for stacking the wafers 1 in one direction. The wafers 1 are
arranged at fixed intervals and accommodated in the pod 2. In the
example shown, the wafers 1 are stacked together in the vertical
direction. An opening 10 is provided on the load port 51 side of
the conveyance chamber 52. The opening 10 is situated such that it
is opposed to the opening of the pod 2 when the pod 2 is arranged
on the load port 51 so as to be close to the opening 10. Further,
an opener (not shown) is provided inside the conveyance chamber 52
and in the vicinity of the opening 10. After the opener removes the
cover 4 from the pod 2, the operation of carrying in or out the
wafers 1 is conducted by the robot arm 54.
[0009] FIG. 7 is a sectional view schematically showing the
construction of the stand 53 of FIG. 6 and the pod 2 placed
thereon. In the lower portion of the pod 2, there are provided
recesses 5, an intake port 7, and an exhaust port 9. Further,
provided on the surface of the stand 53 are positioning pins 12
adapted to be fitted into the recesses 5 to thereby regulate the
installing position of the pod 2, a stand 53 side intake port 14
abutting the pod 2 side intake port 7, and a stand 53 side exhaust
port 16 abutting the pod 2 side exhaust port 9. At the openings of
the stand 53 side intake and exhaust ports 14 and 16, there are
arranged sealing members 18 for enhancing the airtightness of these
portions when these ports abut the pod 2 side ports. In the
vicinity of the openings of the pod side intake and exhaust ports 7
and 9, there are arranged filter members 11, which prevent dust or
the like from entering the pod 2 through these ports. Further, the
stand 53 side intake port 14 and exhaust port 16 are respectively
connected to a substitution gas supply source and a substitution
gas exhaust source, constituting external devices, through check
valves, flow meters, etc (not shown).
[0010] The above-described construction is schematically disclosed,
for example, in Japanese Patent Application Laid-Open No.
2002-531934 or Japanese Patent Application Laid-Open No. 8-203993.
Usually, the wafers 1 for which adhesion of dust or the like is
restrained are brought into such a product accommodating pod 2, and
its internal atmosphere is substituted by an inert gas such as
clean nitrogen, thereby restraining generation of chemical change
such as natural oxidation or organic contamination on the wafer
surfaces in the accommodated state. This substitution of the
internal atmosphere is effected through the gas flow paths formed
by the intake and exhaust ports provided in the pod 2 and the stand
53, with the pod 2 being placed on the stand 53. Thus, it is
necessary to ensure, for the gas flow paths, a size large enough to
allow flowing of a sufficient amount of substitution gas or
internal atmosphere and a sufficient airtightness not to
contaminate the substitution gas or the internal atmosphere. It is
necessary for the sealing members 18 to ensure a sufficient sealing
property meeting these demands.
[0011] It is to be noted that, apart from the connecting portion
between an FOUP and a gas substitution system connected thereto,
such sealing members are applicable to various other uses. However,
when used for an FOUP, the sealing members are required to exhibit
a stable sealing property particularly with respect to the ambient
environment. Thus, in this specification, the sealing members will
be described as applied, in particular, to a technique related to
an FOUP.
[0012] Conventionally, as such a sealing member, a so-called
packing with a ring-like configuration has been used. FIGS. 8A and
8B are schematic sectional views of a pod side exhaust (intake)
port and a stand side exhaust (intake) ports using such packings.
FIG. 8A shows a case in which there is used a so-called dome-shaped
sealing member 18a with a curved inner surface configuration whose
inner diameter decreases toward the upper opening. FIG. 8B shows a
case in which there is used a so-called funnel-shaped sealing
member 18b with a curved inner surface configuration whose inner
diameter increases toward the upper opening.
[0013] When the pressure inside the packing, that is, the pressure
on the gas flow path side, is higher than the pressure outside the
packing, a pressure causing outward deformation of the dome
configuration is applied to the sealing member 18a shown in FIG.
8A. This will occur, for example, when the sealing member 18a is
used on the intake port side. In this case, a deforming pressure is
imparted so as to bring the seal surface of the sealing member 18a
into more intimate contact with the pod 2 side port end portion,
with the result that the sealing property is further enhanced and
becomes more stable. In contrast, when the pressure inside the
packing is lower than the external pressure, that is, when, for
example, the sealing member 18b is used on the exhaust port side,
this difference in pressure results in imparting of a deforming
pressure that causes inward deformation of the dome configuration
as indicated by the arrow in the drawing. As a result, the
intimateness in contact between the seal surface of the sealing
member 18a and the port end portion of the pod 2 deteriorates,
resulting in, in extreme cases, generation of a gap or the
like.
[0014] When the pressure inside the packing is lower than the
pressure outside the packing, a pressure causing inward deformation
of the funnel shape is applied to the sealing member 18b shown in
FIG. 8B. This will occur, for example, when the sealing member 18b
is used on the exhaust port side. In this case, deformation
pressure is imparted so as to bring the seal surface of the sealing
member 18b into more intimate contact with the pod 2 side port end
portion, with the result that the sealing property is enhanced and
stabilized. In contrast, when the pressure inside the packing is
higher than the pressure outside the packing, that is, when, for
example, the sealing member is used on the intake port side, this
difference in pressure results in application of deforming pressure
causing outward deformation of the funnel configuration as
indicated by the arrow in the drawing. As a result, the
intimateness in contact between the seal surface of the sealing
member 18b and the port end portion of the pod 2 deteriorates,
resulting in, in extreme cases, generation of a gap or the
like.
[0015] Thus, it is difficult for the dome-shaped sealing member and
the funnel-shaped sealing member to be commonly used, and it is
necessary to use them selectively according to whether the
environment to be sealed is under positive pressure or negative
pressure. Further, generally speaking, the environment to be sealed
by these sealing members is subject to change in pressure, so that
the sealing property of each seal changes as the ambient pressure
changes. Thus, to ensure a fixed sealing property, it is necessary
to apply beforehand a crushing load to the sealing members to
impart deformation thereto to a fixed degree or more. In this case,
it is necessary to apply a great load, so that as deformation is
repeatedly effected, the sealing members undergo plastic
deformation, resulting in an increase in the frequency with which
the sealing members are replaced. At the same time, to uniformly
deform these sealing members to ensure a satisfactory sealing
property, it is necessary to maintain a fixed surface precision on
the pod side, the stand side, and, further, on the seal surfaces of
the sealing members, resulting in an increase in machining cost for
these members.
[0016] Japanese Patent Application Laid-Open No. 2002-510150, U.S.
Pat. No. 6,164,664, and U.S. Pat. No. 5,988,233 disclose a grommet
of a curved-dome shape or a bellows type sealing member for
preventing plastic deformation due to such repeated load
application. Such configurations seem to provide a satisfactory
effect from the viewpoint of preventing plastic deformation.
However, they are deemed to be incapable of providing a particular
effect with respect to the problem to be solved by the present
invention, that is, change in sealing property due to pressure
change in the in-seal environment.
SUMMARY OF THE INVENTION
[0017] The present invention has been made in view of the above
problem in the prior art. It is an object of the present invention
to provide a sealing member capable of exhibiting a satisfactory
sealing property independently of changes in the positive pressure,
negative pressure, etc. in the in-seal environment and a purge
system using such a sealing member. Further, the present invention
aims to provide a sealing member capable of exhibiting a
satisfactory sealing property without involving a large deformation
load causing excessive deformation of the sealing member or having
to meet a strict demand regarding seal surface precision, and a
purge system using such a sealing member.
[0018] In order to solve the above problem, according to the
present invention, there is provided a purge system for a product
container in which a container-side port formed in the product
container and a stand-side port formed in a stand on which the
container is placed are substantially in contact with each other
via a sealing member, and a gas line for performing at least one of
gas supply and evacuation with respect to an interior of the
container is formed between the stand-side port and the
container-side port, characterized in that the sealing member has:
a ring-shaped main body portion to be fixed to an opening end
portion of a stand-side port opening so as to surround an outer
periphery of the stand-side port opening; a first lip portion
substantially extending from an inner peripheral portion of the
ring-shaped main body portion toward the other opening end portion
different from the opening end portion where the main body portion
is fixed; a second lip portion substantially extending from an
outer peripheral portion of the ring-shaped main body portion
toward the other opening end portion different from the opening end
portion where the main body portion is fixed; and a hole provided
in the main body portion between the first lip portion and the
second lip portion so as to extend to an end surface where the
first lip portion and the second lip portion are not formed, and
that the stand has a gas flow path communicating with the hole and
connected to an exhaust system.
[0019] Note that, in the above system, the first lip portion and
the second lip portion are preferably adapted to be deformed in
directions which are different from each other and in which the
first lip portion and the second lip portion respectively extend,
according to a pressure in a space insulated from an ambient
environment by the sealing member.
[0020] Further, in order to solve the above problem, according to
the present invention, there is provided a purge system for a
product container in which a container-side port formed in the
product container and a stand-side port formed in a stand on which
the container is placed are substantially in contact with each
other via a sealing member, and a gas line for performing at least
one of gas supply and evacuation with respect to an interior of the
container is formed between the stand-side port and the
container-side port, characterized in that the sealing member has:
a ring-shaped main body portion to be fixed to an opening end
portion of a container-side port opening so as to surround an outer
periphery of the opening; a first lip portion substantially
extending from an inner peripheral portion of the ring-shaped main
body portion toward the other opening end portion different from
the opening end portion where the main body portion is fixed; and a
second lip portion substantially extending from an outer peripheral
portion of the ring-shaped main body portion toward the other
opening end portion different from the opening end portion where
the main body portion is fixed, and that the stand has a gas flow
path which communicates with a portion formed between the first lip
portion and the second lip portion when the stand-side port and the
container-side port are held in contact with each other and which
is connected to an exhaust system.
[0021] Note that, in the above system, the first lip portion and
the second lip portion are adapted to be deformed in directions
which are different from each other and in which the first lip
portion and the second lip portion respectively extend, according
to a pressure in a space insulated from an ambient environment by
the sealing member.
[0022] It is to be noted that the above-mentioned products,
container, and stand respectively correspond to the wafer, pod, and
opener stand in the following embodiments. Further, the first lip
portion and the second lip portion respectively correspond to the
inner peripheral lip and the outer peripheral lip in the following
embodiments.
[0023] In order to solve the above problem, according to the
present invention, there is provided a sealing member which, when
connecting together a first space and a second space which are
insulated from an ambient environment, which are capable of
maintaining an internal pressure different from a pressure of the
ambient environment, and which each have an opening, is arranged
between an opening-forming surface of the first space and an
opening-forming surface of the second space to thereby insulate the
first space and the second space from the ambient environment, the
sealing member including: a ring-shaped main body portion to be
fixed to one of the opening-forming surface of the first space and
the opening-forming surface of the second space so as to surround
an outer periphery of the opening; a first lip portion
substantially extending from an inner peripheral portion of the
ring-shaped main body portion toward the other opening-forming
surface different from the opening-forming surface where the main
body portion is fixed; and a second lip portion substantially
extending from an outer peripheral portion of the ring-shaped main
body portion toward the other opening-forming surface different
from the opening-forming surface where the main body portion is
fixed, the sealing member being characterized in that the first lip
portion and the second lip portion are adapted to be deformed in
directions which are different from each other and in which the
first lip portion and the second lip portion respectively extend,
according to pressures in the first space and the second space.
[0024] Note that, in the above-mentioned sealing member, the main
body portion preferably has a hole provided between the first lip
portion and the second lip portion so as to extend to an end
surface where the first lip portion and the second lip portion are
not formed.
[0025] Further, in the above-described sealing member, the first
lip portion has a configuration whose inner diameter gradually
diminishes as the first lip portion is departed from the main body
portion, and wherein the second lip portion has a configuration
whose inner diameter gradually increases as the second lip portion
is departed from the main body portion.
[0026] Further, in order to solve the above problem, according to
the present invention, there is provided a sealing member which,
when connecting together a first space and a second space which are
insulated from an ambient environment, which are capable of
maintaining an internal pressure different from a pressure of the
ambient environment, and which each have an opening, is arranged
between an opening-forming surface of the first space and an
opening-forming surface of the second space to thereby insulate the
first space and the second space from the ambient environment, the
sealing member including: a ring-shaped main body portion to be
fixed to one of the opening-forming surface of the first space and
the opening-forming surface of the second space so as to surround
an outer periphery of the opening; a first lip portion
substantially extending from an inner peripheral portion of the
ring-shaped main body portion toward the other opening-forming
surface different from the opening-forming surface where the main
body portion is fixed; and a second lip portion substantially
extending from an outer peripheral portion of the ring-shaped main
body portion toward the other opening-forming surface different
from the opening-forming surface where the main body portion is
fixed, the sealing member being characterized in that the main body
portion has a hole provided between the first lip portion and the
second lip portion so as to extend to an end surface where the
first lip portion and the second lip portion are not formed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a perspective view, partly in section, of a
sealing member according to the present invention;
[0028] FIG. 2 is a sectional view of the sealing member of FIG.
1;
[0029] FIG. 3 is a schematic perspective view of a system according
to a first embodiment of the present invention, showing the sealing
member of FIG. 1 as installed on the stand of an FOUP load
port;
[0030] FIG. 4 is a schematic sectional view of the stand of FIG. 3
with an FOUP arranged thereon;
[0031] FIG. 5 is a schematic sectional view of the stand of FIG. 3
with an FOUP arranged thereon;
[0032] FIG. 6 is an overall schematic side view of a general
semiconductor wafer processing apparatus to which the present
invention and the prior-art technique are applicable;
[0033] FIG. 7 is a schematic sectional view of the stand of an FOUP
load port using conventional sealing members, with an FOUP placed
thereon;
[0034] FIG. 8A is a schematic sectional view of an intake/exhaust
port end portion of a stand using a conventional system, that is, a
conventional sealing member, and an intake/exhaust port end portion
of an opposing pod;
[0035] FIG. 8B is a schematic sectional view of an intake/exhaust
port end portion of a stand using a conventional system, that is, a
conventional sealing member, and an intake/exhaust port end portion
of an opposing pod;
[0036] FIG. 9 is a schematic sectional view corresponding to FIG. 4
which shows the first embodiment, showing a system according to a
second embodiment of the present invention; and
[0037] FIG. 10 is a schematic diagram showing a system to which the
sealing members of the present invention are suitably applied.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0038] The first embodiment of the present invention will now be
described with reference to the drawings. FIG. 1 is a perspective
view, partly in section, of a sealing member suitably applicable to
a system according to the present invention, and FIG. 2 is a
sectional view of the sealing member of FIG. 1, taken along the
line 2-2. A sealing member 20 used in a system according to the
present invention has a double seal structure, and is composed of a
main body portion 20a formed substantially in a ring-like
configuration, an inner peripheral lip 20b formed on the inner
peripheral side of an end surface of the main body portion 20a, and
an outer peripheral lip 20c formed on the outer peripheral side of
the end surface at which the inner peripheral lip 20b is formed.
Further, between the inner peripheral lip 20b and the outer
peripheral lip 20c of the main body portion 20a, there are formed a
plurality of suction holes 20d extending from one end surface to
the other end surface of the main body portion 20a.
[0039] The inner peripheral lip 20b has a dome-like configuration
with respect to the central axis of the sealing member 20,
gradually decreasing in inner diameter as it extends upwards. In
contrast, the outer peripheral lip 20c has a funnel-like
configuration with respect to the central axis of the sealing
member 20, gradually increasing in inner diameter as it extends
upwards. Due to this construction, when positive pressure is
maintained in the in-seal environment, the dome-shaped inner
peripheral lip 20b suitably provides a sealing effect, and, when
negative pressure is maintained in the in-seal environment, the
funnel-shaped outer peripheral lip 20c suitably provides a sealing
effect, so that it is possible to obtain a satisfactory sealing
property independently of the pressure in the in-seal environment.
Further, the two different lips perform different operations, so
that even when the seal surface precision is low or when the load
for crushing the sealing member is small, it is possible to obtain
a satisfactory sealing property.
[0040] Further, as stated above, the sealing member 20 of this
embodiment is equipped with the suction holes 20d. Due to the
intermediation of the suction holes 20d, when the inner peripheral
lip 20b and the outer peripheral lip 20c abut the pod side port
end, it is possible to evacuate the space defined by the inner
peripheral lip 20b, the outer peripheral lip 20c, and the port end.
Due to this evacuating operation, it is possible for the sealing
member 20 to be more firmly attached to the pod side port end,
thereby achieving a further improvement in terms of sealing
property. Further, through this operation, even if the seal surface
precision is low or if the load for crushing the sealing member is
small, the sealing member itself actively provides a sealing
effect, thereby making it possible to obtain a satisfactory sealing
property.
[0041] While in this example, suction holes are provided in the
sealing member, it is also possible to adopt a construction which
has no such suction holes and which has solely the plurality of
lips. While in this example, the lips of the double seal are
respectively formed in a dome-like and a funnel-like configuration,
this should not be construed restrictively. The same effect can be
obtained as long as configurations are adopted which cause
deformation of the lips in different directions according to the
pressure in the in-seal environment. Further, even when the lips
are formed in the same configuration, it is possible to obtain the
effect of enhancing the intimateness in contact between the sealing
members and port ends by providing between the plurality of lips a
construction having the same effect as the suction holes of this
embodiment.
[0042] An actual system using sealing members according to the
present invention will be briefly described with reference to the
relevant drawing. FIG. 10 shows such a system which is composed of
a first space 31 and a second space 41 insulated from the ambient
space. Connected to the first space 31 are a first gas introduction
system 32 used to increase the internal pressure thereof and a
first exhaust system 33 used to lower the internal pressure
thereof. Similarly, also connected to the second space 41 are a
second gas introduction system 42 used to increase the internal
pressure thereof and a second exhaust system 43 used to lower the
internal pressure thereof. The first space 31 has an opening 35 in
an opening-forming surface 31a, and the second space 41 has an
opening 45 in an opening-forming surface 41a.
[0043] A sealing member 20 according to the present invention is
arranged between the two openings 35 and 45, and is suitably used
to insulate the system from the ambient atmosphere. Further,
although not shown, it is also possible to provide, separately from
the gas introduction systems and the exhaust systems annexed to the
first and second spaces, a system connected to the suction holes
20d of the sealing member 20 of the present invention. Further, the
sealing member of the present invention can also be suitably used
in various modifications of the first and second spaces, e.g., a
construction in which the first space has no gas introduction
system or exhaust system and in which second system has solely an
exhaust system.
[0044] (First Embodiment)
[0045] Next, with reference to the drawings, a case will be
described in which a system according the first embodiment using a
sealing member according to the present invention is applied to a
system related to an FOUP in use at present. It is to be noted that
the semiconductor wafer processing apparatus and the pod to which
the present invention is applied are substantially the same in
construction as the conventional ones described above, so that a
redundant description thereof will be omitted. Further, regarding
the mechanism for opening and closing the cover 4 of the pod 2 such
as an opener, it is not directly pertinent to the present
invention, so that the description of the related-art technique
will be applied, and a detailed description thereof will be
omitted.
[0046] FIG. 3 is a schematic perspective view of the stand 53.
Provided on the surface of the stand 53 are positioning pins 12, an
intake port 14, and an exhaust port 16. Seal members 20 according
to the present invention are arranged in the openings of the intake
and exhaust ports 14 and 16. FIGS. 4 and 5 are schematic sectional
views showing the construction of the stand 53, etc. and the pod 2
placed thereon; FIG. 4 shows the state immediately before the
placing of the pod 2, and FIG. 5 shows the state in which the pod 2
has been placed. In this embodiment, there are provided inside the
stand 53 suction lines 19 for reducing the pressure in the spaces
formed between the sealing members 20 and the intake and exhaust
port end portions. The suction lines 19 communicate with the
above-mentioned spaces through the suction holes 20d, and are
connected to an evacuation system (not shown), which is an external
apparatus.
[0047] In the following, with reference to the drawings, the purge
operation, etc. in an FOUP system to which the present invention is
applied will be described. First, the pod 2 which accommodates
semiconductor wafers 1 in its interior and which is hermetically
closed by the cover 4 is conveyed to a position above the stand 53.
The pod 2 is placed on the stand 53, with the positioning pins 12
protruding from the stand 53 being substantially fitted into the
recesses 5 provided in the lower portion of the pod 2. In this
state, the intake port 7 and the exhaust port 9 on the pod side
abut the intake port 14 and the exhaust port 16 on the stand 53
side through the intermediation of the sealing members 20.
[0048] Here, using the suction lines 19, the operation of
evacuating the interior of the spaces 20e formed between the
sealing members 20 and the intake and exhaust port ends on the pod
2 side is conducted. Through the operation, the pressure in the
spaces 20e is reduced, and the sealing members 20 are firmly
attached to the intake and exhaust port ends on the abutting pod 2
side by the effect of the spaces 20e whose pressure has been
reduced. After the completion of the operation, or while the
operation is being continued, purging operation is performed on the
interior of the pod 0.2. In the purging operation, a substitution
gas is caused to circulated in the following order: the intake port
14 on the stand 53 side, the sealing member 20, the intake port 7
on the pod 2 side, the filter 11, the interior of the pod 2, the
filter 11, the exhaust port 9 on the pod 2 side, the sealing member
20, and the exhaust port 16 on the stand 53 side, whereby the
atmosphere in the pod 2 is substituted.
[0049] By applying the system of this embodiment to a load port as
stated above, it is possible for the intake line and the exhaust
line to maintain a given condition while maintaining a sufficient
sealing property with respect to the external environment
independently of whether it is positive pressure or negative
pressure that is maintained in these lines. Thus, it is possible,
for example, to supply substitution gas to the interior of the pod
2 at higher flow velocity as compared with the related art, thus
making it possible to perform atmosphere substitution more
effectively. Further, by monitoring the internal pressure of the
press-reduced spaces 20e through the intake line 19, it is also
possible to monitor the sealing condition of the sealing members
20.
[0050] In this embodiment, there are employed the stand 53 with
only one intake port system and one exhaust port system and the pod
2 corresponding thereto. However, the construction allowing
application of the present invention is not restricted to the
above-described one; it is desirable to increase or decrease their
number as appropriate taking into account the required gas
substitution speed, the content of the pod 2, etc. Further, it is
also possible to adopt a construction using intake ports only. In
this case, substitution gas is supplied into the pod through the
ports, and the pressure inside the pod is made higher than the
ambient atmospheric pressure, decreasing the sealing force between
the cover 4 and the pod main body 2a. In this way, the inner
atmosphere of the pod 2 is caused to flow out through the gap
between the cover 4 and the pod main body 2a which is generated as
a result of the reduction in sealing force, thereby effecting
evacuation of the interior of the pod.
[0051] (Second Embodiment)
[0052] While in the first embodiment described above the sealing
members are arranged on the stand side, this should not be
construed restrictively; it is also possible for the sealing
members to be arranged on the pod side. In this case, instead of
providing suction holes in the sealing members, it is possible to
connect, to the portion of the seal surface on the stand side which
is in contact with the space formed between the inner peripheral
lip and the outer peripheral lip, an exhaust system for evacuating
the interior of the space. Further, while this example is described
as applied to an FOUP, the application of the present invention is
not restricted to such a system. The sealing member of the present
invention can be applied to any system as long as it is a system
which has a container accommodating a plurality of objects and a
conveyance chamber for carrying the objects from the container to
convey them to an apparatus for processing the objects and which
requires purging of the atmosphere inside the container.
[0053] The second embodiment of the present invention will be
described in detail with reference to the drawings as applied to a
case as mentioned above. FIG. 9 is a drawing showing the second
embodiment, and corresponds to FIG. 4, which was referred to in
describing the first embodiment. In the drawing, the components
having functions similar to those of the corresponding components
of the first embodiment will be indicated by the same reference
numerals. In this embodiment, no suction holes 20d are provided in
the sealing members 20; instead, connected to the portions of the
seal surfaces on the stand side in contact with the spaces formed
between the inner peripheral lips 20b and the outer peripheral lips
20c, are exhaust systems 19 for evacuating the interior of the
spaces. In this embodiment also, the interior of the spaces formed
between the two kinds of lips is reduced in pressure by the exhaust
systems 19, whereby it is possible for the intake line and the
exhaust line to maintain a given condition while maintaining a
sufficient sealing property with respect to the external
environment independently of whether it is positive pressure or
negative pressure that is maintained in the intake and exhaust
lines.
[0054] While the systems of the first and second embodiments have
been described as applied to an FOUP, this should not be construed
restrictively. The present invention can be applied to any system
as long as it is a system which has a container accommodating a
plurality of objects and a conveyance chamber for carrying the
objects from the container to convey them to an apparatus for
processing the objects and which requires purging of the atmosphere
inside the container.
[0055] The sealing member of the present invention is characterized
by a plurality of lips which are deformed in different directions
by a pressure applied to the lip inner peripheral portion. Due to
this construction, it is possible to obtain a superior sealing
property without involving excessive deformation of the lips due to
large load or a high level of surface precision for the seal
surface and the surface opposed thereto. Further, it is possible to
obtain a superior sealing property independently of whether the
pressure in the space insulated from the exterior by the sealing
member is positive pressure or negative pressure with respect to
the external pressure.
[0056] Further, this sealing member has a main body portion, a
plurality of lips, and a space formed between them and the seal
surface of the member opposed thereto and, further, a suction hole
for evacuating the interior of the space. Due to this construction,
the interior of the above-mentioned space is evacuated to more
firmly attach the sealing member to the seal surface opposed
thereto, thereby achieving a superior sealing property. Thus, the
seal surface of the sealing member and the seal surface of the
opposing member are brought into close contact with each other by
physical attraction, whereby even if the surface precision required
of these seal surfaces is of a lower level than the surface
precision required of the conventional seal surfaces, such a
relatively low level of surface precision is permissible. Further,
by monitoring the pressure in the interior of the space, it is also
possible to check the sealing condition.
* * * * *