U.S. patent application number 12/472002 was filed with the patent office on 2009-12-03 for lid opening/closing system for closed container, contained object insertion/takeout system having same lid opening/closing system, and substrate processing method using same lid opening/closing system.
This patent application is currently assigned to TDK CORPORATION. Invention is credited to HIROSHI IGARASHI, TOSHIHIKO MIYAJIMA.
Application Number | 20090294442 12/472002 |
Document ID | / |
Family ID | 41378499 |
Filed Date | 2009-12-03 |
United States Patent
Application |
20090294442 |
Kind Code |
A1 |
IGARASHI; HIROSHI ; et
al. |
December 3, 2009 |
LID OPENING/CLOSING SYSTEM FOR CLOSED CONTAINER, CONTAINED OBJECT
INSERTION/TAKEOUT SYSTEM HAVING SAME LID OPENING/CLOSING SYSTEM,
AND SUBSTRATE PROCESSING METHOD USING SAME LID OPENING/CLOSING
SYSTEM
Abstract
A tunnel is provided between a portion on a support mechanism on
which a pod is loaded and a mini environment that is in
communication with a FIMS. The pod is located in the tunnel when a
lid of the pod is detached from the pod after the lid is held by a
door. The pod is also located in the tunnel when it is at a
position that allows transfer of wafers and to which the pod is
moved after detachment of the lid. The lid and the door that have
been separated from the pod can also be housed in a housing space
annexed to the tunnel. A light emitting portion and a light
receiving portion of an optical sensor are provided respectively on
opposed walls of the tunnel. A pod is provided with a detection
window that can transmit detection light.
Inventors: |
IGARASHI; HIROSHI; (Tokyo,
JP) ; MIYAJIMA; TOSHIHIKO; (Tokyo, 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: |
41378499 |
Appl. No.: |
12/472002 |
Filed: |
May 26, 2009 |
Current U.S.
Class: |
220/200 |
Current CPC
Class: |
H01L 21/67772 20130101;
H01L 21/67775 20130101; H01L 21/67778 20130101 |
Class at
Publication: |
220/200 |
International
Class: |
B65D 51/00 20060101
B65D051/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 27, 2008 |
JP |
2008-137932 |
Claims
1. A lid opening and closing system that detaches a lid of a
storage container having a substantially box-like main body having
an opening on one side thereof that can store an object to be
stored in the interior thereof and the lid that can be detached
from said main body and close said opening to form a closed space
in cooperation with said main body, to open said opening thereby
enabling transfer of said object to be stored into/out of said
storage container, comprising: a storage container support
mechanism that supports said storage container and can move said
storage container along a predetermined direction; a mini
environment separated from an exterior space, in which a mechanism
that transfers said object to be stored is housed under dust
control; a tunnel having an exterior space side opening portion
disposed near a position at which said storage container support
mechanism is loaded with said storage container and a mini
environment side opening portion that opens to said mini
environment to establish communication with said mini environment;
a door that can open and close said mini environment side opening,
said door having a holding mechanism that is in contact with and
holds said lid and being movable, in a posture in which it is
oriented perpendicular to the direction in which said tunnel
extends to substantially close said tunnel, along said
predetermined direction relative to said storage container that is
moved by said storage container support mechanism disposed in said
tunnel; and a mapping sensor provided within said tunnel, that
includes a light emitting portion that emits detection light to an
object to be stored held in said storage container and a light
receiving portion that receives said detection light to detect the
presence/absence of said object to be stored.
2. A lid opening and closing system according to claim 1, wherein
said light emitting portion and light receiving portion are
disposed in accordance with the position of said object to be
stored in the interior of said storage container in a state in
which said storage container is located at a position at which
transfer of said object to be stored into/out of said storage
container is performed.
3. A lid opening and closing system according to claim 1, wherein
there are a plurality of objects to be stored like said object to
be stored, there are a plurality of mapping sensors like said
mapping sensor provided for said objects to be stored respectively,
and at least one of a wavelength range and an emission frequency of
said detection light used by said mapping sensors differs among
said mapping sensors.
4. A lid opening and closing system according to claim 1, wherein
there are a plurality of objects to be stored like said object to
be stored, there are a plurality of mapping sensors like said
mapping sensor provided for said objects to be stored respectively,
and the light emitting portion of one of said mapping sensors and
the light receiving portion of the mapping sensor disposed just
above or below said one mapping sensor are disposed on an inner
surface of said tunnel and at a position opposed to one side of
said storage container.
5. A lid opening and closing system according to claim 1, wherein
there are a plurality of objects to be stored like said object to
be stored, there are a plurality of mapping sensors like said
mapping sensor provided for said objects to be stored respectively,
the light emitting portion of a first mapping sensor among said
plurality of mapping sensors and the light emitting portion of a
second mapping sensor among said plurality of mapping sensors that
is disposed just above or below said first mapping sensor are
disposed on an inner surface of said tunnel and at positions
opposed to one side of said storage container, and the distance
between an axis of detection light emitted from the light emitting
portion of said first mapping sensor and an axis of detection light
emitted from the light emitting portion of said second mapping
sensor increases away from said light emitting portions.
6. A lid opening and closing system according to claim 1, wherein a
light emission side end of said light emitting portion and a light
receiving side end of said light receiving portion are disposed in
such a way as to be flush with or recessed from the inner surface
of said tunnel.
7. A lid opening and closing system that detaches a lid of a
storage container having a substantially box-like main body having
an opening on one side thereof that can store an object to be
stored in the interior thereof and the lid that can be detached
from said main body and close said opening to form a closed space
in cooperation with said main body, to open said opening thereby
enabling transfer of said object to be stored into/out of said
storage container, comprising: a storage container support
mechanism that supports said storage container and can move said
storage container along a predetermined direction; a mini
environment separated from an exterior space, in which a mechanism
that transfers said object to be stored is housed under dust
control; a tunnel having an exterior space side opening portion
disposed near a position at which said storage container support
mechanism is loaded with said storage container and a mini
environment side opening portion that opens to said mini
environment to establish communication with said mini environment;
and a door that has a holding mechanism that is in contact with and
holds said lid, is disposed inside said tunnel, can swing about a
rotational axis perpendicular to said predetermined direction and
parallel to a plane in which said object to be stored extends, and
is movable, in a posture in which it is oriented perpendicular to
the direction in which said tunnel extends to substantially close
said tunnel, along said predetermined direction relative to said
storage container that is moved by said storage container support
mechanism disposed in said tunnel, wherein said tunnel allows the
opening of said storage container to be located in said tunnel when
said door has moved relative to said storage container to detach
said lid from said storage container and has a size large enough to
have a housing space that can house said door and said lid without
interfering with movement of said storage container in said
predetermined direction when said door with said lid held by it has
been swung about said rotational axis, and a mapping sensor that
includes a light emitting portion that emits detection light to an
object to be stored held in said storage container and a light
receiving portion that receives said detection light, to detect the
presence/absence of said object to be stored, is provided within
said tunnel.
8. A lid opening and closing system according to claim 7, wherein
said light emitting portion and light receiving portion are
disposed in accordance with the position of the object to be stored
in the interior of said storage container in a state in which said
storage container is located at a position at which transfer of
said object to be stored into/out of said storage container is
performed.
9. A lid opening and closing system according to claim 7, wherein
there are a plurality of objects to be stored like said object to
be stored, there are a plurality of mapping sensors like said
mapping sensor provided for said objects to be stored respectively,
and at least one of a wavelength range and an emission frequency of
said detection light used by said mapping sensors differs among
said mapping sensors.
10. A lid opening and closing system according to claim 7, wherein
a light emission side end of said light emitting portion and a
light receiving side end of said light receiving portion are
disposed in such a way as to be flush with or recessed from the
inner surface of said tunnel.
11. An object to be stored transfer system that transfers an object
to be stored into/out of a storage container using a lid opening
and closing system, comprising the lid opening and closing system
according to claim 1 and said storage container, wherein said
storage container is provided with a first detection window that
can transmit said detection light and allows said detection light
emitted from said light emitting portion to reach the corresponding
object to be stored and a second detection window that can transmit
said detection light and allows said detection light to reach said
light receiving portion from the interior of said storage
container.
12. An object to be stored transfer system according to claim 11,
wherein there are a plurality of objects to be stored like said
object to be stored, and said first detection window and said
second detection window are provided separately for the respective
corresponding objects to be stored.
13. An object to be stored processing method for detaching a lid of
a storage container having a substantially box-like main body
having an opening on one side thereof that can store an object to
be stored in the interior thereof and the lid that can be detached
from said main body and close said opening to form a closed space
in cooperation with said main body to open said opening thereby
enabling transfer of said object to be stored into/out of said
storage container, transferring said object to be stored into/out
of said storage container, and performing a predetermined
processing on said object to be stored in the exterior of said
storage container, comprising the steps of: preparing a lid opening
and closing system including a dust-controlled mini environment, a
transfer mechanism that transfers an object to be stored and is
provided in said mini environment, a door that can substantially
close an opening portion of said mini environment and hold said
lid, and a support mechanism that supports said storage container
and moves said storage container in a predetermined direction to
cause said door to hold said lid; causing said storage container to
be supported on said support mechanism and fixing said storage
container on said support mechanism; driving said support mechanism
to cause said lid to abut to said door thereby causing said door to
hold said lid; driving said support mechanism and said door in said
predetermined direction relative to each other to thereby separate
said storage container and said lid; swinging said lid and door
about an axis that is perpendicular to said predetermined direction
and contained in a plane in which said object to be stored extends
to thereby bring said lid and door out of a moving region of said
storage container; and driving said storage container in said
predetermined direction to set it at a position at which transfer
of said object to be stored into/out of said storage container is
performed, wherein said storage container is located inside a
tunnel that connects said mini environment and a space in which
operation of causing said storage container to be supported on said
support mechanism is performed at the time when said lid is
separated from said storage container, said lid and door are
located inside said tunnel after said swinging, and said storage
container is located inside said tunnel when it is located at the
position at which transfer of said object to be stored into/out of
it is performed, when said storage container is located at the
position at which transfer of said object to be stored is
performed, detection light is cast to said object to be stored
through a first detection window that can transmit the detection
light provided on said storage container, and whether said object
to be stored is present or absent is determined based on whether or
not the detection light reflected by said object to be stored is
received through a second detection window that can transmit the
detection light.
Description
[0001] This application claims priority from Japanese Patent
Application No. 2008-137932 filed on May 27, 2008, which is hereby
incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a type of a so-called FIMS
(Front-Opening Interface Mechanical Standard) system that is used
when reticles, wafers or the like stored in the interior of a
transfer container called a pod are transferred from one
semiconductor processing apparatus to another in a semiconductor
manufacturing process etc. More specifically, the present invention
relates to a FIMS system or a lid opening and closing system that
can handle, at the same time, a plurality of pods each storing a
few reticles or the like therein and open/close the lids of the
pods to bring reticles or the like into/out of the pods. Here, the
pod is what is called a FOUP (Front-Opening Unified Pod) or a low
profile closed container. The present invention also relates to a
substrate processing method using such a system.
[0004] 2. Description of the Related Art
[0005] Previously, the semiconductor manufacturing process had been
performed in what is called a clean room that is constructed by
establishing a high degree of cleanliness in the room in which
semiconductor wafers are handled. In recent years, however, in view
of an increase in the wafer size and with a view to reduce cost
incurred in maintenance of the clean room, use has been made of a
method of keeping clean only the interior of a processing
apparatus, a pod (or wafer container) and a mini-environment
through which substrates or wafers are transferred between the pod
and the processing apparatus.
[0006] The pod is composed of a substantially cubical body portion
having shelves provided therein that can hold a plurality of wafers
in a parallel and separated state and an opening provided on one
side thereof through which wafers can be brought into/out of it,
and a lid for closing the opening. Those pods which have an opening
portion provided not on the bottom but on one lateral side thereof
(i.e. the side to be directly opposed to the mini-environment) are
collectively called FOUPs (Front-Opening Unified Pods). The present
invention is directed mainly to technologies in which the FOUP is
used. Previously, pods that can each house ten or more wafers had
been used to increase the production efficiency. Recently, however,
with an increase in the diameter of wafers or an increase in the
number of steps of wafer processing, it has been considered
preferable that only a few wafers be stored in one pod and wafers
be supplied to each apparatus in a small lot. A low profile pod
that is specialized to house such a few wafers and handling of such
pods are described in detail in Japanese Patent Application
Laid-Open No. 2004-262654.
[0007] A system that constitutes the above mentioned mini
environment has a first opening portion opposed to the opening of
the pod, a door that closes the first opening portion, a second
opening portion or processing apparatus side opening portion
provided on the semiconductor processing apparatus side, and a
transferring robot that is adapted to reach into the interior of
the pod through the first opening portion to pick up a wafer and
transfer the wafer into the processing apparatus through the second
opening portion on the processing apparatus side. The system that
constitutes the mini environment also has a support table that
supports the pod in such a way that the pod opening is placed just
in front of the door. Typically, the support table is adapted to be
movable toward and away from the door over a predetermined
distance. When the wafers in the pod are to be transferred into the
processing apparatus, the pod placed on the support table is moved
until the lid of the pod abuts the door, and then after abutment,
the lid is detached by the door, whereby the opening of the pod is
opened. By this process, the interior of the pod and the interior
of the processing apparatus are bought into communication with each
other through the mini environment to allow wafer transferring
operations that will be performed repeatedly. All of the support
table, the door, the pod side first opening portion, a mechanism
for opening/closing the door and walls partly defining the mini
environment and having the first opening portion are included in
what is referred to as a lid opening and closing system or an FIMS
(Front-opening Interface Mechanical Standard) system in the context
of the present invention.
[0008] As described above, in the past, systems that handle only
one pod in which ten or more wafers are stored have mainly been
used. However, in the case where the above mentioned low profile
pods are used, it is demanded, in order to reduce the process time,
that a plurality of pods can be operated at the same time or the
time period over which a pod is on the table can overlap the time
period over which another pod is on the table when wafers are
supplied into the mini environment. This wafer handling operation
can also be applied to transfer of other objects such as reticles
that are used in exposure process. In the case where a plurality of
low profile pods are to be handled, the plurality of pods may be
arranged one above another along a vertical direction to make the
area occupied by the system small. A lid opening and closing system
in which pods are arranged in this way has been developed and
disclosed in Japanese Patent Application Laid-Open No. 2000-286319.
In this system, a plurality of pod side opening portions like that
described above are arranged along the vertical directions, and
each door that closes each opening portion is adapted to be swung
about a shaft extending in the longitudinal direction of the
opening portion having a rectangular shape, whereby the space
occupied by the mechanism for opening and closing the doors is made
small.
[0009] A conventional pod that stores a number of wafers at the
same time is transported between processing apparatuses so that the
all the wafers stored in the pod are subjected to a certain
processing in each processing apparatus. In some cases, however,
there may be a wafer(s) that does not satisfy a predetermined
standard after processing, and such a wafer(s) is removed from the
pod. Therefore, although all the shelves in the pod held wafers at
the time when the process was started, some of the shelves become
empty by removal of wafers as the process proceeds. Each of the
processing apparatuses is substantially automated. If there is a
lack of wafer(s) as described above, it is necessary to detect the
lack or absence of wafer(s) and perform appropriate transfer of
wafers out of/into the pod taking into account the absence of
wafer(s). Therefore, in the case where a conventional pod that
stores a number of wafers at the same time is used, it is necessary
to perform what is called a mapping operation, or the operating of
detecting in which storage shelves in the pod wafers are stored, in
each of the processing apparatuses (see Japanese Patent Application
Laid-Open No. 2004-153281).
[0010] In the case where the pod for storing a smaller number of
wafers according to the present invention is used, it is also
necessary to perform the mapping operation as with the above
described conventional pod. In a conventional mapping operation
described in the Japanese Patent Application Laid-Open No.
2004-153281, the presence/absence of wafers is detected by
inserting a so-called mapping sensor having a light emitting
portion and a light receiving portion that are paired into the
interior of the pod and moving the sensor along the direction of
arrangement of the wafers in a scanning manner. If, for example,
the mapping sensor etc. disclosed in the Japanese Patent
Application Laid-Open No. 2004-153281 is to be applied to the
apparatus disclosed in Japanese Patent Application Laid-Open No.
2000-286319, it is necessary that the mapping sensor and means for
carrying the mapping sensor into the interior of the pod and moving
it in a specific direction be provided in the mini environment.
However, in the case of the apparatus in which multiple pods are
arranged one above another as is the case with the apparatus shown
in Japanese Patent Application Laid-Open NO. 2000-286319, it is
difficult to provide a space for accommodating the mapping sensor
itself. Even if there is a space for the mapping sensor, it should
not be allowed to provide a plural number of such structures in the
mini environment, from which, by its nature, driving structure
should be eliminated as much as possible, since the mini
environment is to be kept clean. Therefore, there is a demand for a
mapping sensor has a structure different from that described above
and can suitably be used with a pod and load port for handling a
small number of wafers.
SUMMARY OF THE INVENTION
[0011] The present invention has been made in view of the
above-described problem, and has as an object to provide a lid
opening and closing system for a closed container or pod for
storing a small number of wafers that can map the wafers contained
in the pod. It is also an object of the present invention to
provide a substrate processing method using such a system.
[0012] To achieve the above described object, according to the
present invention, there is provided a lid opening and closing
system that detaches a lid of a storage container having a
substantially box-like main body having an opening on one side
thereof that can store an object to be stored (contained object) in
the interior thereof and the lid that can be detached from the main
body and close the opening to form a closed space in cooperation
with the main body, to open the opening thereby enabling transfer
of the object to be stored into/out of the storage container,
comprising: a storage container support mechanism that supports the
storage container and can move the storage container along a
predetermined direction; a mini environment separated from an
exterior space, in which a mechanism that transfers the object to
be stored is housed under dust control; a tunnel having an exterior
space side opening portion disposed near a position at which the
storage container support mechanism is loaded with the storage
container and a mini environment side opening portion that opens to
the mini environment to establish communication with the mini
environment; a door that can open and close the mini environment
side opening, the door having a holding mechanism that is in
contact with and holds the lid and being movable, in a posture in
which it is oriented perpendicular to the direction in which the
tunnel extends to substantially close the tunnel, along the
predetermined direction relative to the storage container that is
moved by the storage container support mechanism disposed in the
tunnel; and a mapping sensor provided within the tunnel, that
includes a light emitting portion that emits detection light to an
object to be stored held in the storage container and a light
receiving portion that receives the detection light, to detect the
presence/absence of the object to be stored.
[0013] In the above described lid opening and closing system, it is
preferred that the light emitting portion and light receiving
portion be disposed in accordance with the position of the object
to be stored in the interior of the storage container in a state in
which the storage container is located at a position at which
transfer of the object to be stored into/out of the storage
container is performed. It is also preferred that there be a
plurality of objects to be stored like the aforementioned object to
be stored, a plurality of mapping sensors like the aforementioned
mapping sensor be provided for the object to be stored
respectively, and at least one of a wavelength range and an
emission frequency of the detection light used by the mapping
sensors differ among the mapping sensors. In the case where there
are a plurality of objects to be stored, it is preferred that a
plurality of mapping sensors like the aforementioned mapping sensor
be provided for the respective objects to be stored, and the light
emitting portion of one of the mapping sensors and the light
receiving portion of the mapping sensor disposed just above or
below the one mapping sensor be disposed on an inner surface of the
tunnel and at a position opposed to one side of the storage
container. In the case where there are plurality of objects to be
stored, it is preferred that a plurality of mapping sensors be
provided for the respective objects to be stored, the light
emitting portion of a first mapping sensor among the plurality of
mapping sensors and the light emitting portion of a second mapping
sensor among the plurality of mapping sensors that is disposed just
above or below the first mapping sensor be disposed on an inner
surface of the tunnel and at positions opposed to one side of the
storage container, and the distance between an axis of detection
light emitted from the light emitting portion of the first mapping
sensor and an axis of detection light emitted from the light
emitting portion of the second mapping sensor increase away from
the light emitting portions. It is also preferred that a light
emission side end of the light emitting portion and a light
receiving side end of the light receiving portion be disposed in
such a way as to be flush with or recessed from the inner surface
of the tunnel.
[0014] To achieve the above object, according to the present
invention, there is provided a lid opening and closing system that
detaches a lid of a storage container having a substantially
box-like main body having an opening on one side thereof that can
store an object to be stored in the interior thereof and the lid
that can be detached from the main body and close the opening to
form a closed space in cooperation with the main body, to open the
opening thereby enabling transfer of the object to be stored
into/out of the storage container, comprising: a storage container
support mechanism that supports the storage container and can move
the storage container along a predetermined direction; a mini
environment separated from an exterior space, in which a mechanism
that transfers the object to be stored is housed under dust
control; a tunnel having an exterior space side opening portion
disposed near a position at which the storage container support
mechanism is loaded with the storage container and a mini
environment side opening portion that opens to the mini environment
to establish communication with the mini environment; and a door
that has a holding mechanism that is in contact with and holds the
lid, is disposed inside the tunnel, can swing about a rotational
axis perpendicular to the predetermined direction and parallel to a
plane in which the object to be stored extends, and is movable, in
a posture in which it is oriented perpendicular to the direction in
which the tunnel extends to substantially close the tunnel, along
the predetermined direction relative to the storage container that
is moved by the storage container support mechanism disposed in the
tunnel, wherein the tunnel allows the opening of the storage
container to be located in the tunnel when the door has moved
relative to the storage container to detach the lid from the
storage container and has a size large enough to have a housing
space that can house the door and the lid without interfering with
movement of the storage container in the predetermined direction
when the door with the lid held by it has been swung about the
rotational axis, and a mapping sensor that includes a light
emitting portion that emits detection light to an object to be
stored held in the storage container and a light receiving portion
that receives the detection light, to detect the presence/absence
of the object to be stored, is provided within the tunnel.
[0015] In the above described lid opening and closing system, it is
preferred that the light emitting portion and light receiving
portion be disposed in accordance with the position of the object
to be stored in the interior of the storage container in a state in
which the storage container is located at a position at which
transfer of the object to be stored into/out of the storage
container is performed. It is also preferred that there be a
plurality of objects to be stored like the aforementioned object to
be stored, a plurality of mapping sensors like the aforementioned
mapping sensor be provided for the object to be stored
respectively, and at least one of a wavelength range and an
emission frequency of the detection light used by the mapping
sensors differ among the mapping sensors.
[0016] To achieve the above object, according to the present
invention, there is provided an object to be stored transfer system
that transfers an object to be stored into/out of a storage
container using a lid opening and closing system, comprising any
one of the above described lid opening and closing system and a
storage container, wherein the storage container is provided with a
first detection window that can transmit the detection light and
allows the detection light emitted from the light emitting portion
to reach the corresponding object to be stored and a second
detection window that can transmit the detection light and allows
the detection light to reach the light receiving portion from the
interior of the storage container. In this system, in the case
where there are a plurality of objects to be stored like the
aforementioned object to be stored, it is preferred that the first
detection window and the second detection window be provided
separately for the respective corresponding objects to be
stored.
[0017] To achieve the above object, according to the present
invention, there is provided an object to be stored processing
method for detaching a lid of a storage container having a
substantially box-like main body having an opening on one side
thereof that can store an object to be stored in the interior
thereof and the lid that can be detached from the main body and
close the opening to form a closed space in cooperation with the
main body to open the opening thereby enabling transfer of the
object to be stored into/out of the storage container, transferring
the object to be stored into/out of the storage container, and
performing a predetermined processing on the object to be stored in
the exterior of the storage container, comprising the steps of:
preparing a lid opening and closing system including a
dust-controlled mini environment, an object transfer mechanism
which transfers an object and is provided in the mini environment,
a door that can substantially close an opening portion of the mini
environment and hold the lid, and a support mechanism that supports
the storage container and moves the storage container in a
predetermined direction to cause the door to hold the lid; causing
the storage container to be supported on the support mechanism and
fixing the storage container on the support mechanism; driving the
support mechanism to cause the lid to abut to the door thereby
causing the door to hold the lid; driving the support mechanism and
the door in the predetermined direction relative to each other to
thereby separate the storage container and the lid; swinging the
lid and door about an axis that is perpendicular to the
predetermined direction and contained in a plane in which the
object to be stored extends to thereby bring the lid and door out
of a moving region of the storage container; and driving the
storage container in the predetermined direction to set it at a
position at which transfer of the object to be stored into/out of
the storage container is performed, wherein the storage container
is located inside a tunnel that connects the mini environment and a
space in which operation of causing the storage container to be
supported on the support mechanism is performed at the time when
the lid is separated from the storage container, the lid and door
are located inside the tunnel after the swinging, and the storage
container is located inside the tunnel when it is located at the
position at which transfer of the object to be stored into/out of
it is performed, when the storage container is located at the
position at which transfer of the object to be stored is performed,
detection light is cast to the object to be stored through a first
detection window that can transmit the detection light provided on
the storage container, and whether the object to be stored is
present or absent is determined based on whether or not the
detection light reflected by the object to be stored is received
through a second detection window that can transmit the detection
light.
[0018] According to the present invention, it is possible to detect
whether wafers are stored in a pod for storing a small number of
wafers at any time during the lid opening or closing operation.
According to the present invention, sensors may be provided for
respective wafers, and detection errors attributed to interference
between sensors can be prevented. Thus, a reliable detection result
can be obtained. According to the present invention, the sensor is
fitted in a recess provided in the interior of the tunnel in which
ceaseless air flow directed from the mini environment side to the
exterior space side is created. Thus, the presence of the sensor
does not lead to a decrease in the degree of cleanness in the mini
environment.
[0019] The above and other objects, features, and advantages of the
invention will become apparent from the following detailed
description taken in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1A is a side view schematically shows the general
structure of the relevant portion of a lid opening and closing
system according to an embodiment of the present invention and a
pod set on that system.
[0021] FIG. 1B is a schematic cross sectional view taken along line
1B-1B in FIG. 1A.
[0022] FIG. 1C schematically shows the structure shown in FIG. 1A
as seen from the direction indicated by arrow 1C in FIG. 1A.
[0023] FIG. 1D schematically shows the structure shown in FIG. 1A
as seen from the direction indicated by arrow 1D in FIG. 1A.
[0024] FIG. 2 illustrates, in a manner similar to FIG. 1A, the
structure shown in FIG. 1A in the state in which a lid 4 is in
contact with and held by a door 15 after the pod 2 has been
moved.
[0025] FIG. 3A illustrates, in a manner similar to FIG. 1A, the
structure shown in FIG. 1A in the state in which the pod 2 has been
once moved backward and the lid 4 has been detached from the pod
main body 2a.
[0026] FIG. 3B is a schematic cross sectional view taken along line
3B-3B in FIG. 3A.
[0027] FIG. 4A illustrates, in a manner similar to FIG. 1A, the
structure shown in FIG. 1A in the state in which the lid 4 and the
door 15 has been received in the housing space 20c after the door
15 has been swung.
[0028] FIG. 4B is a schematic cross sectional view taken along line
4B-4B in FIG. 4A.
[0029] FIG. 5A illustrates, in a manner similar to FIG. 1A, the
structure shown in FIG. 1A in the state in which the pod 2 has been
moved to a wafer transfer position at which the operation of
transferring a wafer 1 into/out of the pod 2 can be performed.
[0030] FIG. 5B is a schematic cross sectional view taken along line
5B-5B in FIG. 5A.
[0031] FIG. 5C schematically shows the structure shown in FIG. 5A
as seen from the direction indicated by arrow 5C in FIG. 5A, where
illustrations of the lid and the pod main body are omitted.
[0032] FIG. 6 shows the definition of various dimensions in an
embodiment of the present invention.
[0033] FIG. 7A shows, in a manner similar to FIG. 5, an embodiment
of the present invention in which the structure like that shown in
FIG. 1A is equipped with sensors for wafer mapping. FIG. 7A shows
the state in which the pod 2 has been moved to a wafer transfer
position at which the operation of transferring a wafer 1 into/out
of the pod 2 can be performed.
[0034] FIG. 7B is a schematic cross sectional view taken along line
7B-7B in FIG. 7A.
[0035] FIG. 7C schematically shows the structure shown in FIG. 7A
as seen from the direction indicated by arrow 7C in FIG. 7A, where
illustrations of the lid and the pod main body are omitted.
[0036] FIG. 8 illustrates, in a manner similar to FIG. 7C, another
embodiment of the present invention.
[0037] FIG. 9 illustrates, in a manner similar to FIG. 7C, still
another embodiment of the present invention.
[0038] FIG. 10 illustrates, in a manner similar to FIG. 7C, yet
another embodiment of the present invention.
[0039] FIG. 11 schematically illustrates the general structure of a
substrate processing apparatus according to an embodiment of the
present invention.
[0040] FIG. 12 is an enraged view of the relevant portion of the
apparatus according to the present invention shown in FIG. 11.
[0041] FIG. 13 illustrates, in a manner similar to FIG. 12, another
embodiment of the present invention.
DESCRIPTION OF THE EMBODIMENTS
[0042] In the following embodiments of the present invention will
be described with reference to the accompanying drawings. In the
description of the present invention, the relevant structures other
than the sensor will be described first to facilitate description
of the embodiment of the present invention. FIG. 1A schematically
illustrates a part of a low profile pod and the relevant portion of
a lid opening and a closing system that can handle an individual
pod independently, as seen from the side. In practice, a plurality
of structures or systems like that shown in FIG. 1A are arranged
one above another along the vertical direction. To facilitate
explanation, the following description of the embodiment will be
directed to one system. FIG. 1B is a cross sectional view taken
along line 1B-1B in FIG. 1A, showing the structure shown in FIG.
1A. FIG. 1C illustrates the structure shown in FIG. 1A as seen from
the direction indicated by arrow 1C in FIG. 1A (i.e. as seen from
the mini environment). FIG. 1D illustrates the structure shown in
FIG. 1A except for the pod as seen from the direction indicated by
arrow 1D in FIG. 1A (i.e. as seen from the exterior space).
[0043] FIG. 1A illustrates a state in which the pod is set on a
predetermined position on the support table that will be described
later. FIG. 2A illustrates a state in which the lid of the pod is
held by a door after the pod has been once driven to advance. FIG.
3A illustrates a state in which the lid has been removed from the
pod after the pod has been once driven to retract. FIG. 4A
illustrates a state in which the lid opening and closing mechanism
and the lid have been moved by an operation of the lid opening and
closing mechanism to a housing space for them in the interior of a
tunnel. FIG. 5A illustrates a state in which the pod is at a
predetermined position that allows wafer transfer from/into it
after the pod has been driven to advance further. FIGS. 3B, 4B, and
5B illustrate the states shown in FIGS. 3A, 4A and 5A respectively,
in the same manner as FIG. 1B. FIG. 5C illustrates the state shown
in FIG. 5A in the same manner as FIG. 1C. Note that the pod and the
lid are not illustrated in FIG. 5C to facilitate understanding.
[0044] First, a description will be made of a pod to be set on this
lid opening and closing mechanism and wafers stored in the pod. In
the interior of the body 2a of the pod 2 is a space in which two
wafers or objects to be processed are to be housed or stored. The
pod main body 2a is of a low-profile box-like shape and has an
opening 2b on one of the lateral sides thereof. The pod 2 also has
a lid 4 that closes the opening 2b of the body 2a. In the interior
of the body 2a is provided a rack (not shown) having a plurality of
shelves (two shelves, in this embodiment, which are not shown in
the drawings) on which wafers 1 are held horizontally one above
another along the vertically direction. The wafers 1 placed on the
shelves are disposed at a constant interval in the interior of the
pod 2. The wafer 1 is an example of the object to be stored
according to the present invention. The pod 2 is an example of the
storage container according to the present invention. The body 2a,
which has a basically box-like shape, is an example of the body
that is defined to have a substantially box-like shape according to
the present invention. The opening 2b of the pod 2, which has a
basically rectangular shape, is an example of the opening having a
substantially rectangular shape according to the present
invention.
[0045] The lid opening and closing system 10 according to the
present invention includes a support table 13, a door 15, a tunnel
member 21 that defines a tunnel 20, a door opening and closing
mechanism 30 and a wall 11 which is a member that partly
constitutes the outer wall of a mini environment 25 (or a transfer
chamber that will be described later) with which the tunnel is in
communication. The support table 13 has a movable plate 14 having a
flat surface on the top thereof on which the pod 2 is actually to
be placed. The movable plate 14 can move the pod placed thereon
toward and away from a first opening portion 10. Positioning pins
14a are implanted on the flat surface of the movable plate 14. The
positioning pins 14a are adapted to be fit into positioning
recesses (not shown) provided on the bottom surface of the pod main
body 2a to uniquely determine the positional relationship between
the pod 2 and the movable plate 14. The movable plate 14a is
connected with a known drive mechanism (not shown) including a
stepping motor, a ball screw and other parts, and the movable plate
14a on which the pod 2 is set can be stopped at four positions that
will be described later. The four positions include the pod 2 load
position, the lid holding position, the lid detaching position and
the wafer transfer position. The structure including the support
table 13 and the movable plate 14 functions as the storage
container support mechanism or the support mechanism that supports
the pod and moves it in a predetermined direction according to the
present invention.
[0046] The tunnel member 21 includes a peripheral wall portion 21a
that extends from the wall 11 perpendicularly thereto or in the
direction parallel to the moving direction of the movable plate 14
toward the exterior space and has a rectangular cross section that
is perpendicular to the direction it extends and an end wall
portion 21b that partly limits the opening of the peripheral wall
21a that faces the exterior space. The width of the tunnel 20
defined by the tunnel member 21 (i.e. the horizontal dimension or
the dimension of the tunnel 20 in the direction parallel to the
longitudinal side of the surface of the pod that is just opposed to
the tunnel 20) is designed to be larger than the dimension of the
longitudinal side of surface of the pod 2 that is just opposed to
the tunnel 20 so that the pod 2 can be received in the tunnel 20.
The tunnel 20 opens at the mini environment side opening 20a and
the exterior space side opening 20b. Thus, the tunnel 20 functions
as a tunnel that opens in the vicinity of the space in which the
pod 2 is placed (or loaded) on the movable plate 14 to bring the
exterior space and the mini environment into communication with
each other.
[0047] The exterior space side opening 20b has a width or
horizontal dimension equal to the above mentioned width or
horizontal dimension of the tunnel 20 and a height or vertical
dimension that is designed to be slightly larger than the dimension
of the shorter side of the surface of the pod 2 opposed thereto.
Thus, the pod 2 can enter the exterior space side opening 20b. The
mini environment side opening 20a has a width or horizontal
dimension that is larger than the horizontal dimension of the
tunnel 20 that allows the pod 2 to pass. The width or horizontal
dimension of the mini environment side opening 20a is determined
taking into account the size of an L-shaped arm 16 so that an
L-shaped arm 16 that will be described later can be disposed aside
the pod 2. The height or vertical dimension of the mini environment
side opening 20a is slightly larger than the sum of a dimension
that is large enough to provide a housing space 20c in which the
door 15 holding the lid 4 of the pod 2 and a part of the door
opening and closing mechanism provided in the tunnel 20 are housed
and the above mentioned vertical dimension of the opposed surface
of the pod 2.
[0048] The length of the tunnel 20 (that is, the distance from the
exterior space side opening 20b to the mini environment side
opening 20a) is determined based on the relationship between the
length of two straight portions of the L-shaped arm 16 that
supports the door 15 (which will be described later) and the
dimension of the shorter side of the lid 4 of the pod 2 or the
dimension of the shorter side of the door 15. Specifically, the
length of the tunnel 20 is designed in such a way that the portion
of the door 15 or the lid 4 that is closest to the mini environment
in the state in which door 15 is at a retracted position (i.e. the
position that allows transfer of wafers) is kept away from the mini
environment and the opening of the pod 2 at the position at which
detachment of the lid 4 from the pod 2 is performed (i.e. the lid
detachment position) is present in the interior of the tunnel 20.
The end wall portion 21b is designed to limit the exterior space
side opening 20b to the above described size. The horizontal
dimension of the end wall portion 21b is determined according to
the relationship between the size of the opposed surface of the pod
2 and the size of the mini environment side opening portion 20a.
The end wall portion 21b also partly defines the above mentioned
housing space 20c.
[0049] The door 15 includes a contact member 15b and a door body
15a. The contact member 15b is a flat plate member having an
opposed surface that can be opposed to the lid 4 of the pod 2 and
has a shape substantially similar to the lid 4. The door body 15a
holds the contact member 15b by a flat surface to reinforce the
contact member 15b. The longitudinal dimension of the door body 15a
is shorter than the longitudinal dimension of the mini environment
side opening portion 20a so that the possibility of collision of
the door body 15a with the portion that defines mini environment
side opening portion 20a is prevented from occurring when the door
body 15a is swung upon opening or closing the lid 4. The contact
member 15b is disposed at the center of the door body 15a with
respect to the longitudinal direction thereof. On the surface of
the contact member 15b that is opposed to the pod 2 are provided a
suction pads 15c for holding or retaining the lid 4 by vacuum
suction and positioning pins 15d that determine the positional
relationship between the lid 4 and the contact member 15b. The
positioning pins 15d may have the function of retaining the lid 4.
When the positioning pins 15d have the retaining function, they
also serve as so-called latch keys. At positions on the door body
15a on both sides of the contact member 15b, there are provided
slits 15e that pass through the door body 15a from the mini
environment side (or the rear side) to the exterior space side (or
the front side) and extend parallel to the shorter side of the door
body 15a. Ends (or the fixed ends that will be described later) of
the L-shaped arms 16 are attached to portions of the door body 15a
on both sides of the contact member 15b. The suction pads 15c and
an exhaust system (not shown) that is connected thereto to generate
suction force operate as a holding mechanism for objects to be
stored or wafers.
[0050] The L-shaped arm 16 includes a rotation side straight
portion 16a that is connected at its end with the door opening and
closing mechanism 30 by a rotary shaft 30a that will be described
later and a door side straight portion 16b that is connected at its
end with the door body 15a. The end of the door side straight
portion 16b is the fixed end that is fixed to the door body 15a.
The door side straight portion 16b extends parallel to the plane of
the door body 15a. The rotary shaft 30a passes through the tunnel
member 21 and connected with the main body of the drive mechanism
30b of the door opening and closing mechanism 30. The main body of
the rotational drive mechanism 30b is disposed outside the tunnel
member 21. The main body of the drive mechanism 30b includes a
known air cylinder and a link mechanism etc. and rotationally
drives the rotary shaft 30a between two predetermined angular
positions. The rotary shaft 30a is oriented perpendicular to the
predetermined drive direction of the movable plate 14 and parallel
to a plane perpendicular to the pod opening 2b (i.e. the plane of
the wafers stored in the pod).
[0051] In the following, the relationship between various
dimensions of the space in the tunnel 20 and various dimensions of
the L-shaped arm 16 will be described with reference to FIG. 6. In
FIG. 6, t1 represents the thickness of the lid 4, w1 represents the
dimension of the shorter side of the lid 4, l1 represents the
distance from the end face of the fixed end portion of the rotary
shaft side straight portion 16a of the L-shaped arm 16 to the plane
of the suction surface of the suction pads 15c, l1' represents the
distance from the plane of the exterior space side opening 20b to
the plane of the above mentioned suction surface, t2 represents the
thickness of the door 15 (including the suction pads, contact
member and the door body), L1 represents the sum of the l1 and t2,
d1 represents the length of the tunnel 20, 12 represents the length
of the door side straight portion 16b (i.e. distance from the
bottom surface of the door 15 to the end face of the portion of the
door side straight portion 16b connected to the rotary shaft side
straight portion 16a that is opposite to the fixed end portion), w2
represents the length of the shorter side of the door 15 (that is,
the shorter side length of the contact member or the door body,
whichever is the longer in the shorter side dimension), L2
represents the sum of 12 and w2, d2 represents the distance from
the inner surface of the lower wall extending in the longitudinal
direction and partly constituting the peripheral wall 21a of the
portion of the tunnel 20 into which the door 15 is to be swung and
received to the bottom end of the exterior space side opening
portion 20b limited by the end wall portion 21b, and d3 represents
the dimension of the shorter side of the exterior space side
opening 20b. In addition, m1 represents the distance over which the
pod 2 is moved backward from the position at which the surface of
the lid 4 opposed to the door abuts the suction pads 15c after the
pod 2 has been moved forward to the position at which the pod 2 is
stopped after the lid 4 has been detached from the pod 2, and m2
represents the distance over which the pod 2 is moved from the
position at which the pod 2 is stopped after the lid 4 has been
detached from the pod 2 to the wafer transfer position.
[0052] The distance m1 from the position at which the lid 4 of the
pod 2 is held to the position at which the lid 4 has been detached
is designed to be shorter than the distance l1' from the surface of
the suction pads 15c to the exterior space side opening portion 20b
of the tunnel, and the thickness t1 of the lid 4 is designed to be
shorter than the distance m1. With this feature, the opening and
closing operations of the lid 4 are performed always in the
interior of the tunnel 20, and entrance of dust or the like into
the interior of the pod can be prevented during the opening and
closing operations. In addition, by creating air flow from the
interior of the tunnel 20 to the exterior space, the amount of dust
or the like that enters from the exterior space into the pod
through the tunnel before and after the opening and closing
operations can be greatly reduced. The travel distance m2 to the
wafer transfer position is designed to be shorter than the length
of the tunnel 20. Thus, the pod opening is located always in the
interior of the tunnel 20 when the wafer transfer is performed.
This can prevent the pod opening from being directly exposed to
down flow in the mini environment.
[0053] The length w2 of the shorter side of the door 15 is designed
to be shorter than the dimension d3 of the shorter side of the
exterior space side opening portion 20b of the tunnel 20. By
arranging the door at substantially the center of the exterior
space side opening portion 20b with respect to the vertical
direction, air flow paths that extend straightly from the mini
environment side opening portion 20a to the exterior space side
opening portion 20b are formed above the upper side of the door 15
and below the lower side of the door 15. These flow paths and the
slits 15e can create air flow toward the exterior space around the
door 15. The length w1 of the shorter side of the lid 4 is designed
to be equal to or shorter than the length w2 of the shorter side of
the door 15 so that the above mentioned air flow paths are formed
even when the door 15 is holding the lid 4.
[0054] The door 15 that is holding the lid 4 is swung about the
rotary shaft 30a, so that they are received in the housing space
20c. The above mentioned various dimensions are designed in such a
way as to allow this receiving operation. Specifically, the height
L2 of the portion including the L-shaped arm 16 and the door 15
before swinging or the sum of dimension 12 and dimension w2 (that
is, when the lid is held by the door, the distance between the
upper end face of the door or the lid, whichever the higher, and
the lowest surface of the L-shaped arm 16) is designed to be
shorter than the dimension obtained by subtracting the thickness of
the end wall portion 21b from the length d1 of the tunnel 20. With
this design, the door 15 and the lid 4 can be prevented from
extending from the interior of the tunnel 20 into the mini
environment when they are housed in the housing space in the
stationary state.
[0055] It is desirable that the sum t1+t2 of the thickness t1 of
the lid 4 and the thickness t2 of the door 15 be designed to be
smaller than the depth or height d2 of the housing space. It is
also desirable that dimension L1 be designed to be smaller than
dimension d2. By these designs, the lid 4 and the door 15 do not
interfere with the movement of the pod 2 at all when the pod 2 is
moved to the position at which the wafer transfer operation is
performed. In this embodiment, with a view to make the housing
space as small as possible, the L-shaped arms 16 are disposed
outside the moving range of the pod 2, and cut portions 21c are
provided on the end wall portion 21b to prevent it from interfering
with the L-shaped arms 16. By these designs, the housing space can
be made small, and a space in which air flow may stagnate can be
made smaller. Actually, a part of the door 15 or the lid 4
momentarily extends from the interior of the tunnel 20 into the
mini environment 25 as the door 15 is swung, but such the time
period over which it extends is very short and it does not disturb
the down flow significantly. In addition, making the housing space
20c smaller is more effective in preventing disturbance or
generation of dust. Therefore, in this embodiment, the positional
relationship of the components only in the stationary state has
been considered.
[0056] According to the present invention, what is called a mapping
sensor is provided for the above described pod and lid opening and
closing system for the pod in order to map the wafers stored in the
pod. FIGS. 7A, 7B, and 7C show a structure having a mapping sensor
in a manners similar to FIGS. 5A, 5B, and 5C. Components the same
as those shown in FIGS. 5A, 5B, and 5C are denoted by like
reference signs, and they will not be described further. As
mentioned before, in this embodiment, a pod that stores two wafers
arranged one above the other will be described by way of example.
The basic concept of the present invention is that when the pod 2
is kept stationary at a predetermined position, detection light of
a transmissive or reflective optical sensor is introduced into the
pod through a side wall of the pod to detect the presence/absence
of wafers using the detection light. To enable this, the pod 2 to
which the present invention is applied has a detection windows 2c
that is made of a material that can transmit the detection light
and provided in a side wall of the pod main body 2a at positions
corresponding to a light emitting portion and a light receiving
portion (which will be described later) of the sensor according to
the position of the sensor in the embodiment that will be described
later, as shown in FIG. 7A. The detection window 2c that allows
introduction of detection light from the light emitting portion to
the corresponding wafer 1 in the interior of the pod 2 serves as
the first detection window, and the detection window 2c that allows
detection light to travel from the interior of the pod 2 to the
light receiving portion serves as the second detection window.
[0057] In the embodiment shown in FIGS. 7B and 7C, a transmissive
sensor is used. As shown in FIGS. 7B and 7C, that apparatus
according to this embodiment is provided with a first sensor (or a
first mapping sensor) having a first sensor light emitting portion
22a and a first sensor light receiving portion 22b for detecting
the upper wafer 1 in the pod 2 and a second sensor (or a second
mapping sensor) having a second sensor light emitting portion 24a
and a second sensor light receiving portion 24b for detecting the
lower wafer 1. In this embodiment, the sensor light emitting
portions 22a, 24a and the sensor light receiving portions 22b, 24b
are fixed on the opposed side walls 21d, 21e of the tunnel member
21 that defines the tunnel 20. The sensor light emitting portions
22a, 24a and the sensor light receiving portions 22b, 24b are
arranged in such a way that the axis of the detection light
traveling between them obliquely intersects the respective
corresponding wafers to be detected. In this embodiment,
specifically, either one of the light emitting portion and the
light receiving portion of each of the first sensor 22 and the
second sensor 24 is disposed at a higher position and the other is
disposed at a lower position so that the corresponding wafer 1 is
located between them with respect to the thickness or height
direction of the pod 2.
[0058] More specifically, the first sensor light emitting portion
22a is disposed above the plane in which the upper wafer 1 extends,
and detection light emitted from the first sensor light emitting
portion 22a is emitted obliquely downward toward the plane in which
the wafer 1 extends. The corresponding first sensor light receiving
portion 22b is disposed below the plane in which the wafer 1
extends so that it receives the detection light when the wafer 1 is
not present and does not receive the detection light when the wafer
1 is present since the detection light is reflected by the wafer 1.
The second sensor light emitting portion 24a and the second sensor
light receiving portion 24b are disposed in such a way that the
axis of the sensing light traveling between them is parallel to the
axis of the sensing light traveling between the first sensor light
emitting portion 22a and the first sensor light receiving portion
22b. With respect to the direction along the tunnel 20, the light
emitting portions and the light receiving portions are disposed as
close to the wall 11 as possible inside the tunnel 20 and within
the region over which the wafers 1 in the pod 2 extend at the time
when the pod 2 is disposed at the wafer transfer position (i.e. the
position shown in FIGS. 5A, 5B, and 5C). The light emitting
portions and the light receiving portions of the sensors are
fixedly mounted on the side walls 21d and 21e respectively in such
a way that light emission side end and the light receiving side end
(i.e. the ends facing the inner space of the tunnel) of them do not
extend into the interior of the tunnel 20. In other words, the
light emission side end and the light receiving side end of them
are disposed in such a way as to be flush with or recessed from the
inner surface of the tunnel member 21 that define the tunnel
20.
[0059] The light emitting portion and the light receiving portion
used in this embodiment are optical members that function to
enhance the directivity of light, and they are separated from a
light emitting element that actually emits light and a light
receiving element that receives light. The light emitting portion
and the light receiving portion are connected respectively with the
light emitting element and the light receiving element via optical
fibers that are not shown in the drawings. This configuration helps
to make the light emitting portion and the light receiving portion
more compact and leads to advantages that these portions can be
provided on the side walls 21d, 21e more easily and attached
thereto more simply and that maintenance of cleanness in the
interior of the tunnel that will be described later is made more
easy. However, the light emitting element and the light receiving
element may be directly disposed at the position of the light
emitting portion and the light receiving portion in this
embodiment, on condition that a significant modification of the
tunnel member 21 is not necessitated. This may leads to some loss
of the advantages of this embodiment, but provides another
advantage of an increase in the stability in the intensity of
detection light upon emission and reception. In this embodiment,
the detection windows 2c on the pod 2 are provided separately for
the respective corresponding wafers 1. Although this configuration
has an advantage that the wall around the detection window 2c will
prevent unexpected light from entering into the light receiving
portion, this configuration suffers from disadvantages such as
complexity of the structure and an increase in the possibility of
entrance of dust or the like into the tunnel with an increase in
recesses and protrusions on the surface of the pod. In view of
this, the detection windows 2c may be only two large windows
including a first detection window and a second detection window
that can be used for all the wafers 1 stored in the pod 2 to make
the structure simple.
[0060] As described in the foregoing, by providing the sensor light
emitting portions and the sensor light receiving portions for wafer
mapping, the presence/absence of wafers 1 can be detected upon
performing transfer of wafers 1 into/out of the pod 2 before
actually taking out the wafers 1 by the robot. As described above,
the sensors are arranged in such a way as not to protrude into the
tunnel 20 from the opposed side walls 21d, 21e of the tunnel member
21 that defines the tunnel 20. Therefore, provisions of these
components do not cause additional protrusion into the mini
environment 25, which ensures reliability in the movement of the
pod 2. In addition, mapping function can be implemented only by
sensors etc. in regions adjacent the side walls 21d, 21e of the
tunnel member in which a space can be provide relatively easily.
Therefore, the components related to opening and closing the pod 2
can be arranged one above another along the thickness direction
with minimum intervals therebetween, whether the sensors are
provided or not. Inside the tunnel 20 is always present clean gas
flow coming from the mini environment 25 in which cleanness is
controlled toward the exterior space. Therefore, the sensors will
not cause contamination of the mini environment 25. In addition,
since the sensors are kept in a clean environment, deterioration in
its performance and detection errors caused by attachment of dust
or the like is prevented.
[0061] In the above described embodiment, the axes of light of the
sensors are arranged to be parallel to each other in order to
prevent interference of light beams for detecting the respective
wafers. However, in a case where the upper wafer is absent in this
embodiment, there is a possibility that detection light emitted
from the second sensor light emitting portion 24a is reflected by
the wafer 1 and a part of the reflected light reaches the first
sensor light receiving portion 22b due to a certain condition of
the surface of the wafer 1 to cause a detection error consequently.
FIGS. 8 and 9 show arrangements that can perform wafer detection
with reduced possibility of detection errors. FIGS. 8 and 9 show
the exterior space side opening portion 20b as seen from the mini
environment side opening portion 20a in a manner similar to FIG.
7C, where only the opening portions and the sensors are
illustrated.
[0062] In the embodiment shown in FIG. 8, the light emitting
portions and the light receiving portions of the first sensor 22
and the second sensor 24 are arranged in such a way that light
travels in opposite directions between the first sensor 22 and the
second sensor 24. In this arrangement, the arrangements of the
optical fibers and the arrangements of the light emitting elements
and the light receiving elements may be more complicated as
compared to the above described embodiment. However, the
possibility of incidence of unintended light reflected by an
unexpected region on a desired or predetermined light receiving
portion is much lower in this embodiment than the above described
embodiment, and it is considered that this embodiment has a
significant advantage in preventing detection errors. In the
embodiment shown in FIG. 9, the first sensor light emitting portion
22a is disposed below the level of the upper wafer 1, the first
sensor light receiving portion 22b is disposed above the level of
the upper wafer, and the second sensor light emitting portion 24a
and the second sensor light receiving portion 24b are disposed in
the same manner as the embodiment shown in FIG. 7C. Thus, the first
sensor light emitting portion 22a and the second sensor light
emitting portion 24a are arranged relatively close to each other,
while the first sensor light receiving portion 22b and the second
sensor light receiving portion 24b are arranged more distant from
each other than in the case of the embodiment shown in FIG. 7C.
Although this embodiment may be disadvantageous in providing a
space for the first sensor light emitting portion 22a and the
second sensor light emitting portion 24a that are arranged closed
to each other, the large interval between the light receiving
portions in this embodiment leads to a lower possibility of
incidence of reflected light from an unexpected region on a desired
light receiving portion as compared to the embodiment shown in
FIGS. 7A, 7B, and 7C. Thus, this embodiment is advantageous in
preventing detection errors.
[0063] In the above described embodiment, the same type of
detection light is used in both the first sensor 22 and the second
sensor 24. However, in order to eliminate the possibility of
incidence of reflected light from an unexpected region on a desired
light receiving portion, it is effective to differentiate the
wavelengths of the detection light between the first senor 22 and
the second sensor 24. In the case where the wavelength of the
detection light used in the first sensor 22 is different from the
wavelength of the detection light used in the second sensor, even
if detection light emitted from the light emitting portion of the
other sensor is received, it will be determined that the
predetermined detection light is not actually received, as the
received light has a different wavelength. It is also effective to
differentiate the emission frequency (or emission cycle) of the
detection light between the sensors. In this case, it is possible
to determine that light other than detection light received within
a predetermined period(s) in the cycle is light reflected from an
unexpected region. Thus, it is possible to determine whether true
detection light is received or not based on the above-described
determination. In this embodiment, the light emitting end of the
light emitting portion and the light receiving end of the light
receiving portion are arranged to be substantially flush with the
inner surface of the tunnel member 21. However, for example,
recesses may be provided on the side walls 21d, 21e, and the light
emitting end and the light receiving end may be arranged at the
bottom of the recesses. When this arrangement is adopted, the side
walls of the recesses serve as a kind of screens, which effectively
reduce the possibility of incidence of reflected light from an
unexpected region on a desired receiving portion. Alternatively,
wall plates that function as screens may be provided around the
light emitting end and the light receiving end to improve
directivity of the detection light.
[0064] Although transmissive sensors are used in the above
described embodiment, reflective sensors may also be used. FIG. 10
shows an embodiment using reflective sensors in a manner similar to
FIG. 8. In this embodiment, the portion that is intended to reflect
detection light is only the end face of the wafer 1. Therefore, it
can be practically challenging to obtain stable reflected light
having a sufficient light quantity and appropriate directivity.
However, if reflective sensors are used, the number of detection
windows 2c provided on the pod 2 can be reduced. Furthermore, it is
possible to arrange the light emitting portion and the light
receiving portion side by side. Therefore, reflective sensors can
easily be used even in the case where the available space for their
implementation is small.
[0065] In the following, the actual operation of the lid opening
and closing mechanism having the above described structure will be
described. The following description will be directed to a case
where the first sensor 22 and the second sensor 24 that are shown
in FIGS. 7A, 7B, and 7C are used. First, the pod 2 is placed on the
movable plate 14 at the loading position, while the opening of the
tunnel 20 is substantially closed by the door 15, as shown in FIGS.
1A to 1D. After the pod 2 has been set at a predetermined position
on the movable plate 14 with the aid of the positioning pins 14a,
the movable plate 14 is advanced toward the door 15 by a drive
mechanism that is not shown in the drawings. The movable plate 14
driven by the drive mechanism is stopped at the position at which
the lid 4 that closes the pod 2 comes into abutment with the
suction pads 15c. Upon abutment, the positioning pins 15d get into
positioning recesses (not shown) provided on the lid 4, whereby
inappropriate positioning in the abutment of the lid 4 and the door
15 is prevented from occurring. After the abutment, the exhaust
mechanism (not shown) is operated, so that the suction pads 15 hold
lid 4 by suction. The system in this state is illustrated in FIG.
2A.
[0066] After holding of the lid 4 by the door 15 by means of the
suction pads 15c has been achieved, the movable plates 14 on which
the pod 2 is set is moved backward to a predetermined lid
detachment position. With this backward movement, the lid 4 held by
the door 15 is detached from the opening 2b of the pod 2. At the
time of detachment, the lid 4 may possibly be sticking to the pod
main body 2a due to the effect of a sealing member (not shown) or a
pressure difference between the interior of the pod 2 and the
exterior space. In view of this, it is desirable that the pod main
body 2a be secured to the movable plate 14 by some means. In the
case of this embodiment, the positioning pins 14a are designed to
be significantly long so that the pins 14a retain the pod main body
2a against the force acting on the pod main body 2a from the lid 4
during backward movement of the movable plate. FIGS. 3A and 3B
illustrate the system in the state in which the movable plate 14 is
at the predetermined lid detachment position after it has been
moved backward, and the lid 4 has been detached from the pod main
body 2a.
[0067] While the movable plate 14 is kept stationary at the above
described position, the door 15 is swung by the door opening and
closing mechanism 30. The swinging of the door 15 is stopped in the
state illustrated in FIGS. 4A and 4B in which the door 15 and the
lid 4 are housed in the housing space 20C. Thereafter, the movable
plate 14 is moved forward, and at the time when the pod 2 comes to
the wafer transfer position (or the position at which the operation
of transferring wafers out of/into the pod is to be performed), the
movable plate 14 is stopped. The system in this state is
illustrated in FIGS. 5a and 5B. In this state, the first sensor 22
and the second sensor 24 are operated to perform the so-called
mapping or the operation of detecting the presence/absence of the
upper and lower wafers 1 in the pod 2. The wafer(s) 1 detected by
the mapping operation is taken out of the pod 2 and subjected to a
predetermined processing. In the aforementioned state, the lid 4
and the door 15 are located beneath the pod 2 with the movable
plate 14 between. For this reason and thanks to an additional
effect of down flow generated in the mini environment 25, dust or
the like on the lid 4 etc. cannot enter the interior of the pod 2
easily. In addition, by generating down flow, the interior of the
mini environment is kept at a pressure higher than the pressure in
the exterior space. Consequently, flow of gas directed from the
mini environment to the exterior space is always present in the
tunnel 20, whereby the possibility that dust on the lid 4 or other
parts is brought toward the opening 2b of the pod 2 is further
reduced. In the present invention, furthermore, an appropriate gap
is designed to be left between the inner surface of the tunnel 20
and the periphery of the door and the outer periphery of the pod in
order to achieve the above effect. This gap is designed in such a
way that the pressure difference between the mini environment and
the exterior space is not made unduly low, and gas flows through
that gap at a flow rate that is not unduly high).
[0068] In this embodiment, in order to separate the mini
environment 25 and the exterior space to a significant extent and
to limit the region that allows communication between these spaces,
the system is designed in such a way that air flow that flows from
inside the housing space 21 straightly to the exterior space cannot
be created. However, there is a small gap between the surface of
the lid 4 that faces the door 15 and the contact member 15b in the
region other than the region in contact with the suction pads 15c.
If there is dust or the like in that gap, it is considered to be
difficult for the above described system to efficiently remove it
out to the exterior space. In the case where the degree of dust
control in the external environment is not so high, the possibility
that dust or the like remains on the opposed surface of the lid 4
would be high. In such an environment, it is preferred that a slit
be provided on the end wall portion 21 at a position to be aligned
with the above mentioned gap so that an air flow path from the mini
environment 25 to the above mentioned gap and then to the slit to
facilitate removal of dust in the gap to the exterior space by
creating air flow flowing through the gap. In the above described
embodiment, the number of wafers 1 stored in the pod 2 is two, and
the system adapted to use this pod has been described by way of
example. However, the present invention is not limited to this
particular embodiment. It is preferred that the number of sensors
used for mapping be changed in accordance with the number of wafers
1 stored in the pod 2.
[0069] By providing the lid opening and closing system having the
above described structure, at the time when the lid of the pod is
detached from the pod main body, the lid and the mechanism for
opening and closing the lid can be disposed at a position at which
they stay out from downward air flow, or specifically, at a
position in the tunnel at which any part of them does not extend
into the mini environment. In this state, the presence/absence of
wafers or the like can be detected, and the operation of
transferring wafers or the like out of/into the pod can be
performed based on the detection result. Consequently, dust or the
like will not be blown off from the lid of the pod or the mechanism
for opening and closing the lid by down flow. Other pods, lids,
mapping sensors, and drive mechanisms for them etc. are also
disposed in the respective tunnels. Therefore, the possibility that
dust or the like coming from one lid etc. attaches to another lid
or other parts can be reduced. The system enables mapping of wafers
or the like stored in the pod without any decrease in the degree of
cleanness of the load port having a basic structure by using
minimum space.
[0070] In the following, a substrate processing apparatus in which
the lid opening and closing system described in the foregoing is
practically used will be described as an exemplary embodiment of
the present invention. FIG. 11 is a side view schematically showing
the general structure of a semiconductor wafer processing apparatus
(or substrate processing apparatus) 40 that can operate in a
so-called mini-environment system. The semiconductor wafer
processing apparatus 40 is mainly composed of a load port section
(or FIMS system, lid opening and closing apparatus) 10, a transfer
chamber (or mini environment) 25, and a processing chamber 29.
These sections are separated at their joining portions by the wall
11 on the load port side and the communication passage 28 on the
processing chamber side. In the transfer chamber 25 of the
semiconductor wafer processing apparatus 40, downward air flow
(down flow) from the top to the bottom of the transfer camber 25 is
created by a fan filter unit 33 provided in the top portion thereof
to keep a high degree of cleanliness by bringing out dust. The
bottom panel of the transfer chamber 25 has, for example, a mesh,
which provides outlet paths of the down flow. With the above
described structure, dust-controlled air is ceaselessly introduced
into the transfer chamber 25, and dust present in the chamber or
dust brought into the chamber from a pod or other components is
always brought downward by the down flow and discharged to the
exterior.
[0071] Pods 2 or storage containers for silicon wafers or the like
(which will be simply referred to as wafers hereinafter) are set on
support tables 14 of the load port section 10. In the apparatus
according to this embodiment, three pods are set one above another
and two wafers 1 are contained in each pod 2. As described before,
the interior of the transfer chamber 25 is kept in a highly clean
condition for transferring wafers 1. Inside the transfer chamber 25
is provided a transfer robot 35 serving as a wafer transfer
mechanism that can actually hold a wafer. The transfer robot 35 can
move in the direction along which the pods 2 are arranged (i.e. the
vertical direction). The robot arm 35a of the transfer robot 35 can
rotate 360 degrees about an axis. Wafers 1 are transferred between
the interior of the pods 2 and the interior of the processing
chamber 29 by the transfer robot 35. In the processing chamber 29
are generally provided various systems that perform various
processing such as film deposition and film processing on the
surface of the wafer. These systems will not be described in
further detail herein, since they do to have direct relevance to
the present invention.
[0072] The pod 2 is composed of a box-like main body 2a having an
opening on one side thereof and an interior space in which two
wafers 1 to be processed are to be stored, and a lid 4 that closes
the opening. In the interior of the main body 2a is provided a rack
having a plurality of shelves on which wafers are to be placed one
above another along one direction. The wafers 1 placed thereon are
stored or contained in the interior of the pod 2 at a certain
interval. In the exemplary system described herein, the tunnel
member 21 has a plurality of tunnels (three tunnels) 20 provided
therein at positions corresponding to the movable plates 14. The
details of the structure of each tunnel are the same as those of
the structure that has been already described above. The structures
of the principal components such as the tunnel 20 relevant to the
present invention have been discussed in the above description of
the embodiment. For this reason and to make understanding of the
drawings easier, further description and detailed illustration
thereof will not be made.
[0073] FIG. 12 is an enlarged view of the lid opening and closing
system 10 shown in FIG. 11. In conventional FISM systems adapted to
a pod in which a number of wafers are stored, since the lid of the
pod necessarily has a somewhat large size, the door that is adapted
to detach the lid and closes the opening portion of the mini
environment is necessarily required to be moved in the mini
environment and stopped in it. In the present invention, since the
door has an elongated plate-like shape, the state allowing transfer
of wafers out of/into the pod is achieved by enabling relative
movement of the pod and the door by an amount equal to the width or
thickness of the lid and swinging the door and the lid to outside
the moving region of the pod. Accordingly, the door opening and
closing mechanism can be disposed in the tunnel that is independent
from the mini environment 25 as shown in FIG. 1.
[0074] For example, in the case where the robot is driven by a
combination of operations of three systems such as X, Y, and Z
direction systems, if there are obstacles to be avoided in driving
the robot with respect to all the driving directions, a very
complex safety circuit is needed in order to achieve safe operation
of the robot. In the present invention, there is no structure that
extends into the mini environment 25 that can be obstacle to
driving of the robot with respect to the vertical direction (or the
Z-axis direction). Therefore, a safety circuit is actually needed
only when wafers are taken out of or inserted into the pod.
Accordingly, the circuit configuration can be made much simpler.
Furthermore, since no structure is provided in the mini environment
25 except for the robot 35, there is no structure that can disturb
down flow, particularly in the region near the pod opening.
Therefore, efficiency of dust removal by the down flow is enhanced.
In addition, the possibility of dust generation from the door or
other components caused by a disturbance in the down flow is
reduced. According to the SEMI (Semiconductor Equipment and
Materials International) standards established in the semiconductor
industry, it is not allowed to provide a projection on the inner
surface of the walls that define the mini environment in the
vicinity of the opening portion through which wafers are
transferred. The present invention is compliant with the
standards.
[0075] In the above described embodiment, the movable plate 14 is
provided on the support table 13, and the pod 2 is placed thereon.
However, the structure to which the present invention is applied is
not limited to this embodiment. For example, the pod 2 may be
suspended from above. Such a modification is shown in FIG. 13 in a
manner similar to FIG. 12. In the case where the pod 2 is
transported by so-called automatic handling, an upper flange 2c
fixedly provided on the top surface of the pod 2 is used. The pod 2
is suspended by the flange when transported. In this modification,
the pod 2 that has been transported is held by a suspension member
17, and the pod 2 is transferred with the suspension member 17 by a
suspension member drive mechanism 19.
[0076] In this modification, the movable plate 14 used in the above
described embodiment can be eliminated, and the entrance of the
plate into the interior of the tunnel 20 with the pod 2 can be
prevented. Therefore, it is possible to eliminate the space for
receiving the plate that enters, which is required to be provided
in the housing space 20c in the above described embodiment.
However, in the above described embodiment, the pod main body 2a
can be retained on the movable plate 14 with a strength that can
resist the force acting on the pod main body 2a upon detachment of
the lid 4 to some extent. In this modification, there is a
possibility that the simple suspension does not provide a force
strong enough to retain the pod main body 2a upon detachment of the
lid, and it may be necessary to design the structure in such a way
as to enable retaining of the pod main body or provide an
additional component for this purpose. However, since such a
component can be additionally used, the storage container support
mechanism or the support mechanism in the present invention should
be construed to include the structure like that component.
[0077] According to the present invention, there can be provided a
lid opening and closing system that can perform mapping of wafers
stored in a low profile pod upon opening and closing the lid of the
pod. This system does not have any component that extends into the
mini environment. Since the system does not have component or
structure that extends into the pod loading side, full use can be
made of the effect of down flow created in the mini environment. In
addition, the control program of the transfer robot used in the
wafer transferring operation can be made easy and high speed
movement of the robot can easily be achieved, since a component or
structure to be avoided by the robot upon movement along the
Z-axis, in which high speed movement is required, has been
eliminated. Furthermore, since the openings of pods are separated
by the tunnels, the possibility that dust or the like brought by a
certain pod or generated from a certain pod enters another pod can
be reduced. Still further, since during the time of wafer transfer,
the lid, door, and its drive mechanism are disposed beneath the
bottom of the pod and covered by the bottom portion of the pod, the
possibility that dust generated from them enters the interior of
the pod can be reduced.
[0078] Although the above described embodiments or examples have
been directed to FOUP and FISM systems, the applications of the
present invention are not limited to them. The lid opening and
closing apparatus according to the present invention can be applied
to any front open type container in which a plurality of objects
are to be stored and any system that opens and closes the lid of
the container and transfers objects out of/into the container.
[0079] As many apparently widely different embodiments of the
present invention can be made without departing from the spirit and
scope thereof, it is to be understood that the invention is not
limited to the specific embodiments thereof except as defined in
the appended claims.
* * * * *