U.S. patent application number 10/698421 was filed with the patent office on 2004-05-27 for wafer processing apparatus capable of mapping wafers.
This patent application is currently assigned to TDK CORPORATION. Invention is credited to Igarashi, Hiroshi, Miyajima, Toshihiko, Okabe, Tsutomu.
Application Number | 20040099826 10/698421 |
Document ID | / |
Family ID | 32324602 |
Filed Date | 2004-05-27 |
United States Patent
Application |
20040099826 |
Kind Code |
A1 |
Igarashi, Hiroshi ; et
al. |
May 27, 2004 |
Wafer processing apparatus capable of mapping wafers
Abstract
A wafer processing apparatus on which a pod having an opening is
detachably mounted is provided with a door unit and a mapping unit
provided with a transmitting type sensor having an emitter and a
detector forming a slot therebetween. The emitter and the detector
are moved toward the opening in the pod and are plunged into the
interior of the pod after a door is opened by the door unit, and
the slot between the emitter and the detector crosses an end
portion of a wafer to thereby detect the presence or absence of the
wafer. Thereby, a mechanism portion liable to produce dust which
may adhere to the wafer and cause the contamination thereof can be
disposed separately from the pod.
Inventors: |
Igarashi, Hiroshi; (Chuo-ku,
JP) ; Okabe, Tsutomu; (Chuo-ku, JP) ;
Miyajima, Toshihiko; (Chuo-ku, JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
TDK CORPORATION
Chuo-ku
JP
|
Family ID: |
32324602 |
Appl. No.: |
10/698421 |
Filed: |
November 3, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10698421 |
Nov 3, 2003 |
|
|
|
10301841 |
Nov 22, 2002 |
|
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Current U.S.
Class: |
250/559.29 |
Current CPC
Class: |
G01V 8/12 20130101; H01L
21/67265 20130101; H01L 21/67772 20130101; Y10S 414/137
20130101 |
Class at
Publication: |
250/559.29 |
International
Class: |
G01V 008/00 |
Claims
What is claimed is:
1. A wafer mapping apparatus for determining whether a wafer is
present or not on each of shelves when a pod having a box which has
an opening and the shelves for taking custody of the wafer in
parallel along a vertical direction and a lid separably covering
said opening is fixed to a wafer processing apparatus, said wafer
mapping apparatus comprising: a first sensor for determining
whether the wafer is present or not on shelves; a mapping frame for
supporting said first sensor; a movable portion for supporting said
first sensor movable in the vertical direction through said mapping
frame in a state in which said sensor is plunged into said box; a
timing plate having index means disposed at predetermined
intervals; and second sensors provided so as to sandwich said index
means therebetween, wherein a signal in response to each of said
shelves is generated by said timing plate and said second sensor in
accordance with a vertical movement of said sensor.
2. A wafer mapping apparatus according to claim 1, wherein said
movable portion and said second sensors are located underside of
lower edge of said opening, and are provided within a substantially
closed space.
3. A wafer mapping apparatus according to claim 1, wherein said
movable portion is connected with a door which holds said lid of
said pod, apart said lid from said box, and moves said lid
substantially below said box.
4. A wafer mapping apparatus according to claim 2, wherein said
movable portion is connected with a door which holds said lid of
said pod, apart said lid from said box, and moves said lid
substantially below said box.
5. A wafer mapping apparatus according to claim 1, wherein said
mapping frame is tilted so that the upper side thereof is apart
from a plane forming said opening of said pod in a state that said
opening is closed bys said lid, and said sensor is plunged into
said box after said opening is opened.
6. A wafer mapping apparatus according to claim 2, wherein said
mapping frame is tilted so that the upper side thereof is apart
from a plane forming said opening of said pod in a state that said
opening is closed bys said lid, and said sensor is plunged into
said box after said opening is opened.
7. A wafer mapping apparatus according to claim 3, wherein said
mapping frame is tilted so that the upper side thereof is apart
from a plane forming said opening of said pod in a state that said
opening is closed bys said lid, and said sensor is plunged into
said box after said opening is opened.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to a wafer processing apparatus
including a wafer mapping apparatus having a function of detecting
the presence or absence of a wafer. Also, this invention
particularly relates to a wafer processing apparatus for detecting
the presence or absence of a wafer on each shelf of a rack
(shelves) on which the wafer is placed and which is provided in the
interior of a clean box for keeping a wafer in a good condition for
use in a semiconductor product, a product related to an electronic
part, an optical disc product or the like during the manufacture
thereof.
[0003] 2. Related Background Art
[0004] In recent years, in a wafer processing process in the
manufacture of a semiconductor product or the like which requires a
high degree of cleanness, there has been adopted a technique which
does not an entire room relating to the treating process into a
highly clean environment. In this technique, a small space
(hereinafter referred to as minienvironment) kept highly clean is
provided in each wafer processing apparatus in a wafer
manufacturing process. This aims at keeping a small space only in
the wafer processing apparatuses and a container (hereinafter
referred to as the pod) for keeping the wafer in a good condition
during the movement among those wafer processing apparatuses at a
high degree of cleanness. Thereby, facility investment and facility
maintenance expenses required when the entire room relating to the
wafer treating process is kept in a highly clean environment are
curtailed to thereby obtain the same effect as keeping the entire
room relating to the wafer processing process in a highly clean
environment and realize an efficient production process.
[0005] In the pod, there are disposed a rack having shelves on each
of which a wafer is placed. In these shelves, wafers are contained
in such a state that a shelf is allotted to a wafer. The wafers
placed on the shelves are moved in each wafer processing apparatus
with the movement of the pod. In some cases, however, there occurs
a wafer which does not satisfy a predetermined standard in the
processing process of each wafer processing apparatus, and the
wafer which does not satisfy the predetermined standard is removed
from the shelf in the pod. Accordingly, at the initial stage of the
manufacture, each shelf of the rack (shelves) is filled with the
wafer, but as each processing step of the wafer processing
apparatus progresses, the number of shelves in the pod on which the
wafer is absent increases.
[0006] The wafer processing apparatus automatically effects the
treatment of the wafer and therefore usually it is provided with a
wafer transport robot (hereinafter simply referred to as the
transport robot). The transport robot gains access to a shelf of
the rack in the pod, transports the wafer and executes the wafer
processing process. Although a wafer to be processed is absent on
that shelf, if the transport robot gains access to that shelf on
which the wafer is absent in order to transport the wafer, there
will occur a useless movement process from after the transport
robot gains access to that shelf until it returns to its original
position. Further, as such a useless movement process increases,
the amount of processed wafers is reduced as a whole. So, it
becomes necessary to detect the presence or absence of the wafer on
each shelf of the rack in the pod in each wafer processing
apparatus to thereby judge in which shelf of the shelves in the pod
in each wafer processing apparatus a wafer is contained and in
which shelf a wafer is not contained (mapping).
[0007] The detection of the presence or absence of the wafer for
mapping will now be described with reference to FIG. 1 and FIGS. 7A
and 7B to 9 of the accompanying drawings. FIG. 1 shows the whole of
wafer processing apparatus 50. The wafer processing apparatus
chiefly includes a load port portion 51 and a minienvironment
portion 52. The load port portion 51 and the minienvironment 52 are
partitioned by a partition 55 and a cover 58. A stand 53 is
disposed on the load port portion 51. A pod 2 can be placed on and
fixed to the stand 53. The stand 53 is movable on the load port
portion 51 toward or away from the minienvironment 52 side. The
interior of the minienvironment 52 is kept at a high degree of
cleanness to process a wafer 1. The robot arm 54 of a transport
robot for effecting the transport of the wafer 1 is provided in the
minienvironment 52. The pod 2 has an opening portion in one surface
thereof, and includes a box-shaped main body portion 2a having a
cavity space for containing the wafer 1 therein, and a lid 4 for
sealing the opening portion. A shelf having a plurality of shelves
is disposed in the main body portion 2a. The wafer 1 can be placed
on each of the plurality of shelves. Each of the shelves is
disposed with a predetermined spacing from the shelf adjacent
thereto so that adjacent wafers 1 may not contact with each
other.
[0008] An access opening 10 is formed in the minienvironment 52 on
the load port portion 51 side. The position at-which the access
opening 10 in the minienvironment 52 is disposed is a position at
which the pod 2 fixed onto the stand 53 is right opposed to the
opening portion of the pod 2 when it is moved on the load port
portion 51 toward the minienvironment 52 side so as to become
proximate to the access opening 10.
[0009] FIGS. 7A and 7B are enlarged views of an opener 3 in a
conventional wafer processing apparatus. The opener 3 is provided
near the access opening 10 inside the minienvironment 52. The
opener 3 includes a door 6 and a door arm 42 of an elongated shape.
A bar extending perpendicularly to the lengthwise direction of the
door arm 42 is disposed at one end of the door arm 42. On the other
hand, a fixing member 46 having a through-hole is attached to the
door 6, and the bar provided at one end of the door arm 42 extends
through this hole in the door 6, whereby the door 6 is pivotably
fixed to the door arm 42. The other end of the door arm 42 is
formed with a hole. The door arm 42 is rotatably supported by this
hole being coupled to a hole at the tip end of a rod 37 which is a
portion of an air-driven type cylinder 31 by a pivot 40. A
through-hole is formed between the aforementioned one end and the
other end of the door arm 42, and a pin extends through this hole
and a hole in a fixing member 39 fixed to the support member 60 of
a movable portion 56 to thereby constitute a fulcrum 41.
Accordingly, the door arm 42 is pivotable about the fulcrum 41 by
the expansion and contraction of the rod 37 by the driving of the
cylinder 31. The fulcrum 41 of the door arm 42 is fixed to the
support member 60 provided on an upwardly and downwardly movable
portion 56. The door 6 has holding ports 11a and 11b, and can hold
the lid 4 of the pod 2 by vacuum absorption. The opener 3 is
mounted on the movable portion 56 vertically movable to move up and
down the door arm 42 and the door 6 together with each other. The
movable portion 56 is vertically movable along the wall surface of
the minienvironment 52.
[0010] Accordingly, when the processing of the wafer is to be
effected, the pod 2 is first disposed on the stand 53 so as to
approach the access opening 10, and the lid 4 is held by the door
6. When the rod of the cylinder 31 is then contracted, the door arm
42 is moved about the fulcrum 41 so as to move away from the access
opening 10. By this movement, the door 6 is pivotally moved with
the lid 4, and the lid 4 is detached from the pod 2. Thereafter,
the movable portion 56 is moved downwardly and the lid 4 is
transported to a predetermined retracted position.
[0011] In the detection of the wafers 1 on the shelves of the rack
in the pod 2, it becomes necessary for a detector to scan each
shelf at least once while sweeping along a direction in which the
wafers 1 are stacked, to thereby effect the detection of the wafers
1. To effect this sweeping movement for detecting the wafers 1,
various methods are conceivable. For example, there is a method of
providing a detector on a portion of the robot arm 54 and moving
the detector by this robot arm 54 to thereby execute the detecting
operation. The robot arm 54, however, is a device originally
prepared to effect the transport of the wafer 1, and if the robot
arm 54 is to effect the detection of the wafer, the robot arm 54
cannot perform the transporting operation for the wafers 1 during
the detecting operation, and this leads to the disadvantage that
the amount of treated wafers 1 is reduced.
[0012] As another method, there is a method of providing a detector
on a portion of an opening and closing device for the lid 4 of the
pod 2 and detecting the wafer 1 by the detector during the
unsealing of the lid 4. FIGS. 7A and 7B show an apparatus adopting
this method. In this apparatus, there is provided a mapping frame 5
comprised of a frame member disposed so as to-surround the door 6.
A pair of bar-like members 13a and 13b are disposed on the upper
portion of the mapping frame 5. A transmitting type sensor 9 as a
detector is mounted on the tip end of each of these bar-like
members 13a and 13b. The transmitting type sensor 9 forms a pair by
an emitter 9a and a detector 9b. FIG. 8 is a view of the mapping
frame 5 of this apparatus as it is seen from its upper side. As
shown in this figure, these bar-like members 13a and 13b have their
respective one end fixed for the pivotal movement about shafts 36a
and 36b on the mapping frame 5, and are rotated by cylinders 34a
and 34b disposed also on the mapping frame 5 and can evolve so as
to protrude from the mapping frame 5 toward the interior of the pod
2. That is, when the detecting operation for the wafer 1 is not
executed, the bar-like members 13a and 13b are contained so as to
be within the width of the mapping frame 5 along the axis of the
frame of the mapping frame 5 (a bar-like member 13c and a bar-like
member 13d). When the detection of the wafer 1 is to be effected,
the bar-like member 13c and the bar-like member 13d are rotated by
nearly 90 degrees about shafts 36a and 36b, respectively, by a
cylinder 34a and a cylinder 34b and the bar-like members 13a and
13b evolve toward the wafer 1. In this state, the emitter 9a
attached to the tip end of the bar-like member 13a and the detector
9b attached to the tip end of the bar-like member 13b become
opposed to each other. When the bar-like members 13a and 13b evolve
so as to protrude from the mapping frame 5, slots are formed
between the emitter 9a and the detector 9b. The emitter 9a and the
detector 9b are mounted so that the edge portion of the wafer 1 may
be located between these slots. Also, the mapping frame 5 is
mounted on the movable portion 56 so as to be moved up and down
with the door 6. Further, the mapping frame 5 is supported also by
the rod of another cylinder 43 so as to be movable up and down
discretely from the door 6.
[0013] Reference is now had to FIG. 9 to describe the mapping of a
wafer processing apparatus having the wafer mapping function. To
carry out mapping in this apparatus, the pod 2 is disposed on the
stand 53 so as to be proximate to the access opening 10, and the
lid 4 is held by the door 6. When the rod of the cylinder 31 is
contracted, the door arm 42 is moved about the fulcrum 41 so as to
separate from the access opening 10. Then the door 6 is pivotally
moved with the lid 4 and the lid 4 is detached from the pod 2.
Here, when the emitter 9a and the detector 9b have evolved, the rod
of the cylinder 32 is contracted to a preparatory position in which
it becomes insertable into the interior of the pod 2 (a position
located from the edge of the opening in the pod 2 to the vertically
lower side which is the inner side of the pod 2) to thereby move
down the mapping frame 5. After the mapping frame 5 has been moved
down to the preparatory position, the cylinder 34a and the cylinder
34b are actuated to thereby evolved the emitter 9a and the detector
9b. Thereupon, the emitter 9a and the detector 9b become inserted
into the interior of the pod 2. In this state, as shown in FIG. 8,
when the wafer 1 is seen from a direction perpendicular to the
surface of the wafer 1, there is brought about such a positional
relation that the wafer 1 exists in the slot between the emitter 9a
and the detector 9b. When here, the movable portion 56 is moved
down, the mapping frame 5 is moved down with the door 6, and the
slot between the emitter and the detector crosses the end portion
of the wafer 1 to be located when the wafer 1 exists on each of the
shelves. The emitter 9a and the detector 9b can scan each shelf of
the shelves which sweeping along the direction in which the wafers
1 are stacked, to thereby detect the presence or absence of the
wafers 1 and effect mapping.
[0014] The above-described method, however, has suffered from the
following problems.
[0015] (1) The emitter 9a and the detector 9b disposed on the
mapping frame 5, in order to prevent them from interfering with the
pod 2, are designed to be capable of evolving so as to be rotated
by the cylinders 34a and 34b and protrude from the mapping frame 5
toward the interior of the pod 2. The evolving mechanism, including
such an air cylinder, is generally liable to produce dust. Further,
in this structure, it is necessary that the cylinder 34a and the
cylinder 34b be disposed in proximity to the pod 2. This leads to
the problem that the dust produced from the cylinder 34a and the
cylinder 34b adheres to the wafer 1 and causes the contamination of
the wafer 1.
[0016] (2) Also, an air-driven type cylinder is used in the
operation of opening and closing the door 6, the operation of
moving up and down the door 6 and the operation of moving up and
down the mapping frame 5. This is for obtaining a force necessary
to appropriately crush a seal provided on the lid 4 of the pod 2 to
keep the degree of cleanness in the pod. If a driving device for
opening and closing the lid is a motor, a great load corresponding
to a moment comprising the distance from the fulcrum 41 to the door
6 multiplied by a force necessary to appropriately crush this seal
becomes necessary, and this leads to a disadvantageous problem.
Accordingly, a driving device for pivotally moving the door 6 and a
driving device for retracting the door 6 to a predetermined
position are made discrete from each other, and both of them are
air-driven type cylinders. In the mapping operation, however, the
air-driven type cylinder poses the problem that there cannot be
generated a reference signal indicative of the distance over which
the emitter 9a and the detector 9b are actually moved, for
contrasting with a signal generated when the slot between the
emitter 9a and the detector 9b crosses the wafer 1, cannot be
generated.
[0017] (3) Also, in the opening and closing apparatus of the type
as previously described which is provided with a linear motor and
in which the opener 3 is opened in a horizontal direction with the
door 6, there is the problem that the production of dust from the
linear motor cannot be prevented.
SUMMARY OF THE INVENTION
[0018] It is an object of the present invention to provide a wafer
processing apparatus in which a mechanism for evolving and
containing a transmitting type sensor need not be disposed in
proximity to a wafer and dust produced from the wafer processing
apparatus to evolve and contain the transmitting type sensor during
the evolving and containing operation for the transmitting type
sensor can be prevented from contaminating the wafer.
[0019] It is another object of the present invention to provide a
wafer processing apparatus on which a pod is detachably mounted,
having an access port through which a wafer is put in and out, the
pod having a box having an opening, shelves for taking custody of
wafers, and a lid for separably covering the opening, the wafer
processing apparatus detecting whether the wafer is present on each
of the shelves, the wafer processing apparatus comprising: a door
unit including a door capable of holding the lid and for covering
the access port; a door arm for pivotally supporting the door near
one end thereof; the door arm being supported for pivoted movement
about a first fulcrum disposed on a door arm supporting member
disposed near the other end of the door arm by the door arm
supporting member; and a door opening and closing driver for
rotating the door arm about the first fulcrum; a mapping unit
including a transmitting type sensor having an emitter and a
detector; a mapping frame for holding the emitter and the detector
so as to protrude toward the access port, the emitter and the
detector being disposed in face-to-face relationship with each
other, a slot being formed between the emitter and the detector; a
mapping frame arm for supporting the mapping frame near one end
thereof, the mapping frame arm being supported for pivotal movement
about a second fulcrum disposed on a mapping frame arm supporting
member disposed near the other end of the mapping frame arm by the
mapping frame arm supporting member; and a mapping frame driver for
rotating the mapping frame arm about the second fulcrum; and a
movable portion for supporting the door arm supporting member and
the mapping frame arm supporting member, and moving the door unit
and the mapping frame; wherein the emitter and the detector are
moved toward the access port and the opening and are plunged into
the pod after the door is opened with the lid by the door unit, and
by the movable portion, the slot between the emitter and the
detector crosses an end portion of a wafer to be located when a
wafer is present on each of the shelves.
[0020] The above and other objects of the invention will appear
more fully hereinafter from the consideration of the following
description taken in connection with the accompanying drawings
wherein one example is illustrated by way of example.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 generally shows a wafer processing apparatus to which
the present invention is applied.
[0022] FIG. 2A is an enlarged view of the vicinity of the opener of
a wafer processing apparatus according to the present embodiment as
it is seen from a side thereof.
[0023] FIG. 2B is an enlarged view of the vicinity of the opener of
the wafer processing apparatus according to the present embodiment
as it is seen from the inside of a minienvironment.
[0024] FIG. 3A is a front view of the movable portion of the opener
of a wafer processing apparatus according to Embodiment 1 as it is
seen from a load port side.
[0025] FIG. 3B is a view of the movable portion of the opener of
the wafer processing apparatus according to Embodiment 1 as it is
seen from a side thereof.
[0026] FIG. 4 is a view showing the sequence of the mapping of a
wafer, and shows a state when the mapping preparation has been
completed.
[0027] FIG. 5 is a view showing the sequence of the mapping of the
wafer, and shows a state when the mapping operation has been
completed.
[0028] FIG. 6 is a view showing the sequence of the mapping of the
wafer, and shows a state when all of the mapping and the opening
operation of a lid have been completed.
[0029] FIG. 7A is an enlarged view of the vicinity of the opener of
a conventional wafer processing apparatus as it is seen from a side
thereof.
[0030] FIG. 7B is an enlarged view of the vicinity of the opener of
the conventional wafer processing apparatus as it is seen from the
inside of a minienvironment.
[0031] FIG. 8 shows the transmitting type sensor portion of the
conventional wafer processing apparatus.
[0032] FIG. 9 shows the details of the operation of a mapping frame
provided with the transmitting type sensor of the conventional
wafer processing apparatus.
[0033] FIG. 10 shows the arrangement of the emitter and the
detector of the transmitting type sensor with regard to the wafer
placed on a shelf.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
First Embodiment
[0034] Embodiment 1 will hereinafter be described with reference to
the drawings.
[0035] FIG. 1 shows the whole of a wafer processing apparatus 50.
The wafer processing apparatus 50 is comprised chiefly a load port
portion 51 and a minienvironment 52. In the minienvironment 52 of
the wafer processing apparatus 50, in order to exhaust dust and
keep a high degree of cleanness, a constant air flow is produced
from the upper portion toward the lower portion of the
minienvironment 52 by a fan (not shown) provided in the upper
portion of the minienvironment 52. Thus, the dust is always
exhausted downwardly.
[0036] The load port portion 51 and the minienvironment 52 are
comparted by a partition 55 and a cover 58. A stand 53 for placing
a pod 2 thereon is installed on the load port portion 51, and can
be moved on the load port portion 51 toward or away from the
minienvironment 52.
[0037] The pod 2 is provided with a main body 2a which is a box
having a space for containing a wafer 1 therein and provided with
an opening, and a lid 4 for detachably closing the opening. In the
main body 2a, there is disposed a rack having shelves arranged in a
predetermined direction. In the present embodiment, this
predetermined direction is a vertical direction. A wafer can be
placed on each of the shelves. The interior of the minienvironment
52 is kept at a high degree of cleanness to treat the wafer 1.
[0038] An access opening 10 somewhat larger than the lid 4 of the
pod 2 is formed in the minienvironment 52 on the load port portion
51 side. An opener 3 for opening and closing the lid 4 of the pod 2
is provided on a side of the access opening 10 which is the
interior of the minienvironment. 52. Also, the robot arm 54 of a
transport robot is provided in the interior of the minienvironment
52. After the lid 4 of the pod 2 is opened, the robot arm 54 puts
in and out the wafer 1 contained in the pod 2 through an opening in
the pod 2 and the access opening 10 to thereby effect predetermined
treatment.
[0039] The opener 3 will be described here with reference to FIGS.
2A and 2B. FIG. 2A is a magnified view of the load port portion 51,
the pod 2, the opener 3 and the lid 4 in FIG. 1, and FIG. 2B is a
view of the portions shown in FIG. 2A as they are seen from the
inside of the minienvironment 52. The opener 3 is provided with a
door 6 and a mapping frame 5. The door 6 is a plate-shaped member
of a size which can cover the access opening 10, and the surface
thereof is provided with holding portions 11a and 11b which are
vacuum intake holes. A surface located on the pod 2 side when the
door 6 covers the access opening 10 is such a flat surface as can
closely contact with the lid 4. A fixing member 46 having a hole is
attached to the door 6. It is fixed by a pivot shaft 45 which is
provided on the upper end of a door arm 42 pivotally extending
through this hole. A hole is formed in the lower end of the door
arm 42, and the door arm 42 is coupled and rotatably supported by a
pivot shaft 40 extending through that hole and a hole in the tip
end of a rod 37 which is a portion of an air-driven type door
opening and closing cylinder 31 which is a driving device for
opening and closing the door.
[0040] A mapping frame 5 is a structure comprising a frame member
disposed along the access opening 10 and so as to surround the
periphery of the door 6. The mapping frame 5 is mounted on the
upper ends of a mapping frame arm 12a and a mapping frame arm 12b
extending long in the frame member under it. Holes are formed in
the lower ends of the mapping frame arm 12a and the mapping frame
arm 12b, and a pivot shaft 44 extends through those holes and a
hole in the tip end of a rod 38 which is a portion of an air-driven
type mapping frame driving cylinder 35 which is a mapping frame
driving device, whereby the two mapping frame arms are coupled
together and rotatably supported. The mapping frame arm 12a and the
mapping frame arm 12b extend symmetrically and in parallel to each
other along the center axis of the mapping frame 5 and in a
vertical direction to equally support a load. A rod 47
perpendicular to each of the mapping frame arm 12a and the mapping
frame arm 12b is mounted between the upper ends and lower ends of
the mapping frame arm 12a and the mapping frame arm 12b. A fixing
member 39 which is a fulcrum supporting portion of a shape
extending perpendicularly from a support member 60 is disposed on
the support member 60. The fixing member 39 has a through-hole
parallel to the support member 60. A bearing (not shown) is
disposed in the through-hole in the fixing member 39, and the outer
ring of the bearing is fitted to the inner wall of the
through-hole, and the inner ring of the bearing pivotally supports
the rod 47. Thereby, the rod 47 constitutes a fulcrum 41 in a state
in which it is contained in the through-hole in the fixing member
39.
[0041] This fulcrum 41 is constituted as a coaxial fulcrum serving
as the fulcrum of the mapping frames 12a and 12b and the fulcrum of
the door arm in common. That is a discrete through-hole is formed
between the upper end and lower end of the door arm 42. The rod 47
extends through this through-hole and constitutes the fulcrum
41.
[0042] The door arm 42 is pivotally movable about the fulcrum 41 by
the expansion and contraction of the rod 37 by the driving of the
cylinder 31. The fulcrum 41 of the door arm 42 is fixed to the
support member 60 provided on an upwardly and downwardly movable
portion 56. The door 6 has holding ports 11a and 11b, and can hold
the lid 4 of the pod 2 by vacuum absorption. The door arm 42 is
disposed so as to be substantially vertical when the door 6 is
urged against the access opening 10 (hereinafter referred to as
waiting state), and the door arm 42 is rotated, whereby the door 6
is moved away from the wall surface of the minienvironment 52.
[0043] By the expansion and contraction of the rod 38 by the
driving of the mapping frame driving cylinder 35, the mapping frame
arm 12 is pivotally movable about the fulcrum 41. That is, the
mapping frame arm 12 is also fixed to the support member 60
provided on the upwardly and downwardly movable portion 56. The
mapping frame 5 is disposed so as to be inclined with separating
from the wall surface of the minienvironment 52 when the door 6 is
in its waiting state. That is, in this state, the mapping frame arm
12a and the mapping frame arm 12b are supported in a state in which
they are inclined so as to have a certain angle with respect to the
door arm 42, and the upper portion of the mapping frame 5 is spaced
apart by a predetermined distance from the wall surface of the
minienvironment 52. On the other hand, when from this waiting
state, the mapping frame 5 rotates the mapping frame arm 12a and
the mapping frame arm 12b in a direction to abut against the wall
surface of the minienvironment 52, the mapping frame 5
substantially abuts against the wall surface of the minienvironment
52. A sensor supporting bar 13a and a sensor supporting bar 13b are
fixed to a frame member disposed in the upper portion of the
mapping frame 5 so as to protrude toward the wall surface of the
minienvironment 52. The emitter 9a and detector 9b of transmitting
type sensor 9 which is a first transmitting type sensor are
attached to the tip ends of the sensor supporting bar 13a and the
sensor supporting bar 13b, respectively, in opposed relationship
with each other and so as to form a slot therebetween.
[0044] The wafer processing apparatus 50 is provided with a movable
portion 56 for moving up and down the opener 3. FIG. 3A is a view
of the movable portion 56 of the opener 3 as it is seen from the
load port portion 51 side, and FIG. 3B is a view taken along the
arrow X of FIG. 3A. The movable portion 56 is provided with an
air-driven type rodless cylinder 33 for effecting vertical movement
and a support member 60, and is disposed below the underside of the
pod 2 so as to be downstream of the pod 2 with respect to an air
flow. The fixing member 39, the air-driven type cylinder 31 and the
cylinder 35 are mounted on the support member 60. The movable
portion 56 is provided on the load port portion 51 side, and
supports the opener 3 on the minienvironment 52 side from a slot 57
formed in a partition 55 by the door arm 42, the mapping frame arm
12a and the mapping frame arm 12b. The slot 57 is formed with the
direction of movement of the movable portion 56, i.e., in the case
of the present embodiment, the vertical direction, as the
lengthwise direction. The load port portion 51 and the
minienvironment 52 are partitioned by a cover 58 so that the degree
of cleanness in the minienvironment 52 may not be lowered by the
slot 57. Further, a limiter 59 for preventing the overrun of the
opener 3 when the opener 3 is moved down is provided below a
partition 55. The partition 55 is provided with the rodless
cylinder 33, a guide 61a and a guide 61b along the slot 57. The
movable portion 56 effects upward and downward movement along the
guide 61a and the guide 61b by the rodless cylinder 33. A timing
plate 7 is provided sideways of the movable portion 56 along the
rodless cylinder 33.
[0045] The timing plate 7 is a plate-shaped member extending in a
direction along the rodless cylinder 33, and has in the lengthwise
direction thereof index means disposed at predetermined intervals.
In the present embodiment, the timing plate has notches as the
index means having a certain width and disposed at predetermined
intervals to form an uneven portion 12. The member of the uneven
portions corresponds to the number of the shelves of the wafer
arranging shelf in the pod, and the uneven portions are disposed so
that when the movable portion comes to any shelf, a notch
corresponds thereto without fail. In the movable portion 56 on the
timing plate 7 side, a transmitting type sensor 8 which is a second
transmitting type sensor is fixed onto the lateral partition 55.
The emitter and detector of the transmitting type sensor 8 are
disposed in opposed relationship with each other and slots are
formed therebetween. The emitter and detector of the transmitting
type sensor 8 are disposed so that the uneven portions 12 provided
with notches at predetermined intervals provided on the timing
plate 7 may be interposed among the slots of the transmitting type
sensor 8, and the uneven portions 12 of the timing plate 7 can be
detected in conformity with the movement of the movable portion
56.
[0046] A transmitting type sensor 62 is provided on the support
member. 60 of the movable portion 56, and a limiter 64 is provided
on the partition 55 near the lower side of the slot 57. Design is
made such that when a protruding portion 62 intercepts light from
the limiter 64, a stop signal is outputted to the movable portion
and the movement of the whole of the opener 3 is stopped.
[0047] Reference is now had to FIGS. 2A and 2B and FIGS. 4 to 6 to
describe how the detection of the wafer 1 for the mapping of the
wafer 1 is effected on the basis of these constructions. FIGS. 2A
and 2B show a waiting state, FIG. 4 shows a state in which the lid
4 is opened and closed and the mapping frame 5 is operated, FIG. 5
shows a state in which the detection of the wafer 1 has been
completed, and FIG. 6 shows a state in which the mapping frame 5
has been returned to the waiting state after the completion of the
detection of the wafer 1.
[0048] Wafers 1 which have satisfied the treatment standard of
pre-treatment are contained in the shelf in the pod 2 which has
terminated the preceding treating process, while on the other hand,
wafers 1 which have not satisfied the standard are eliminated from
the process at the stage of the pre-treatment. In the shelf for the
wafers 1, there are mixedly present shelves on which the wafers 1
are present and shelves on which the wafers 1 are not present. The
pod 2 in this state, as shown in FIGS. 2A and 2B, is placed on the
stand 53 on the minienvironment 52 and is moved so as to approach
the access opening 10.
[0049] In this state, the opener 3 is in the waiting state. That
is, the rod 37 of the cylinder 31 for opening and closing the door
is in its most expanded state and the door arm 42 is in a state in
which it urges the door 6 against the access opening 10 about the
fulcrum 41 to thereby cover the access opening. In the present
embodiment, in this state, the arm 42 is in its vertically erect
state. On the other hand, the rod 38 of the mapping frame driving
cylinder 35 is in its most contracted state and the mapping frame
arms 12a and 12b are in a state in which they act to pull the
mapping frame 5 apart from the wall surface of the minienvironment
52 about the fulcrum 41. That is, in the present embodiment, the
mapping frame arms 12a and 12b are in an oblique state at a certain
angle with respect to the door arm 42.
[0050] FIG. 4 shows a state in which the pod 2 becomes proximate to
the access opening 10 and the door 6 holds the lid 4. When the pod
2 becomes proximate to the access opening 10, the lid 4 of the pod
2 comes into close contact with the door 6, and the door 6 effects
the holding of the lid 4 of the pod 2 from holding portions 11a and
11b by vacuum suction. When the door 6 holds the lid 4, the
cylinder 31 for opening and closing the door works to contract the
rod 37. Thereupon the door arm 42 pulls a pivot shaft 40 provided
on the end portion of the door arm 42 toward a support base 60
side, and is pivotally moved by the fulcrum 41 so as to pull the
door 6 apart from the access opening 10 in accordance with the
principle of the lever, and opens the lid 4 from the pod 2.
[0051] Assuming that the mapping frame arms 12 are pivotally moved
after the lid 4 has been opened, the movable portion 56 is slightly
moved down to a position on which the upper end of the mapping
frame 5 enters the position of the access opening 10. After the
termination of this downward movement, the mapping frame arms 12
actually start their pivotal movement. That is, the mapping frame
arms 12 are pivotally moved until the rod 38 of the mapping frame
driving cylinder 35 is expanded and the mapping frame 5
substantially abuts against the periphery of the access opening 10.
Thereupon the transmitting type sensor 9 attached to the upper side
of the mapping frame 5 comes out of the access opening 10 and is
inserted into the pod 2. At this point of time, the emitter 9a and
the detector 9b, like the conventional transmitting type sensor 9
as shown in FIG. 8, constitute a slot which is a detection space
with the wafer 1 lying on a straight line linking the emitter 9a
and the detector 9b together.
[0052] When in this state., the movable portion 56 is vertically
moved, mapping is executed. That is, the opener 3 is moved down to
a position shown in FIG. 5 by the rodless cylinder 33. The emitter
9a and the detector 9b are moved down in a direction perpendicular
to the surface of the wafer 1 with the movable portion 56 and the
opener 3 and therefore, when the wafer 1 is present on a shelf of
the shelves, light emitted from the emitter 9a is intercepted, and
when the wafer 1 is absent on the shelf, the light of the emitter
9a is not intercepted.
[0053] If design is made such that the detector 9b generates a
non-transmission signal when it is interrupted by the wafer 1, and
the detector 9b generates a transmission signal when it is not
interrupted by the wafer 1, it can be judged that when the
non-transmission signal is detected, the wafer 1 is present, and it
can be judged that when the transmission signal is detected, the
wafer 1 is absent. Further, as will hereinafter be described,
general judgment is effected with a signal indicative of the
position of the wafer 1 added thereto.
[0054] The emitter and detector of the transmitting type sensor 8
are disposed so as to have interposed therebetween the uneven
portions 12 which are cut-aways at predetermined intervals which
are index means provided on the timing plate 7 and therefore, when
the movable portion 56 is moved down, the transmitting type sensor
8 is also moved down therewith and detects the uneven portions 12
of the timing plate 7. Design is made such that when at this time,
the transmitting type sensor 8 passes a notched portion, the light
from the emitter of the transmitting type sensor 8 is not
intercepted, but is sensed by the detector to thereby generate a
transmission signal, and when the transmitting type sensor 8 passes
an un-notched portion, the light from the emitter of the
transmitting type sensor 8 is intercepted and is not detected by
the detector to thereby generate a non-transmission signal.
Accordingly, if the uneven portions 12 of the timing plate 7 are
preset so that the point of time at which the emitter and detector
of the transmitting type sensor 9 pass each shelf of the shelves in
the pod 2 and point of time at which the emitter and detector of
the transmitting type sensor 8 pass the notched portion may
correspond to each other, the transmission or non-transmission
signal detected by the transmitting type sensor 8 is indicative of
the signal of a shelf of the shelves which the transmitting type
sensor 9 actually passes. If this is compared with the result of
the detection of the transmission or non-transmission signal
detected as a result of the transmitting type sensor 9 having its
light intercepted by the wafer 1 and when the transmitting type
sensor 8 detects a signal corresponding to a shelf of the shelves,
the transmitting type sensor 9 has its light intercepted, it can be
judged that the wafer 1 is present on that shelf, and if at that
time, the transmitting type sensor 9 has its light not intercepted,
it can be judged that the wafer 1 is absent on that shelf. This
detecting operation is executed for all wafers 1, and when the
detection terminating position of the opener 3 shown in FIG. 5 is
reached, the detecting operation is completed.
[0055] Of course, an un-notched portion can also be index means
having a certain width and disposed at predetermined intervals.
[0056] Thereafter, the rod 38 of the cylinder 35 for opening and
closing the mapping frame is again contracted, whereupon the
mapping frame arms 12 are pivotally moved and the mapping frame 5
is moved away from the access opening 10. When the rod 38 is most
contracted the movement of the mapping frame 5 is completed. The
movable portion 56 is then moved to the lowest point, thus opening
the lid 4 and completely a series of detecting operations for the
mapping of the wafer 1. This state is the state shown in FIG.
5.
[0057] As described above, the emitter and detector of the
transmitting type sensor 9 are fixed to the mapping frame, and
provision is made of the mapping frame arms 12 and the mapping
frame driving cylinder which are means for pivotally moving the
mapping frame 5, and further these devices are provided on the
movable portion 56 sufficiently spaced apart from the access
opening 10, whereby it has become unnecessary to provide a device
for performing the evolving operation of the transmitting type
sensor near the wafer 1.
[0058] Also, by utilizing the timing plate 7 and the transmitting
type sensor 8, a synchronizing signal corresponding to a shelf of
the shelves in the pod 2 can be easily generated and therefore,
even if a drive motor is not used as a driving device, the accurate
mapping of the wafer 1 becomes possible. If the timing plate 7 is
thus utilized, an air-driven type cylinder which cannot generate a
signal can be utilized for the mapping of the wafer 1.
[0059] While in the present embodiment, the shelves are disposed so
as to be arranged vertically and the movable portion 56 is
vertically moved up and down and the mapping frame 5 is a structure
comprising a frame member disposed along the access opening 10 and
so as to surround the door 6, the same effect is achieved as long
as the direction in which the shelves are arranged and the
direction in which the movable portion 56 is moved are
substantially the same and the mapping frame 5 has a member on
which a pair of transmitting type sensors 9 can be disposed so that
a line linking the pair of transmitting type sensors 9 together on
the starting point side of the movement of the movable portion 56
may cross the semiconductor wafer placed on a shelf of the shelves.
That is, the mapping frame can achieve a similar effect if as in
the present embodiment, the shelves are disposed so as to be
arranged vertically and a pair of transmitting type sensors 9 can
be disposed above the door so that when the movable portion 56 is
vertically moved up and down, a line linking the pair of
transmitting type sensors 9 together may cross the semiconductor
wafer placed on a shelf of the shelves.
[0060] Also, while in the present embodiment, the fulcrum of the
door arm 42 and the fulcrum of the mapping frame 5 are made common
to each other by the fulcrum 41, a similar effect will be achieved
even if the two fulcrums are made discrete from each other. That
is, an effect similar to that of the present invention will be
achieved even if different fulcrums are provided as a first fulcrum
to be provided on the door arm 42 and a second fulcrum to be
provided on the mapping frame.
[0061] While in the present embodiment, the movable portion 56, the
fulcrum 41, the cylinder 31 for opening and closing the door and
the mapping frame driving cylinder 35 are made integral with one
another, they need not always be made integral with one another in
obtaining the effect of the present invention. A similar effect
will be achieved as long as these mechanisms are disposed
downstream of the pod 2 with respect to the air flow.
[0062] Furthermore, in theory, the emitter 9a and the detector 9b
can be arranged so that the light beam (a center of the light beam)
from the emitter 9a to the detector 9b is parallel to the surface
of the wafer placed on each shelf. In practice, however, as shown
in Fig.10, the emitter 9a and the detector 9b should be arranged
with an angle to the surface of the wafer placed on each shelf.
This is because the light beam from the emitter 9a diffusely
reflects by the surface of the wafer on a shelf. That is, in order
to avoid the diffuse reflection, the emitter 9a and the detector 9b
may be arranged so that the light beam from the emitter 9a to the
detector 9b is inclined with an angle to the surface of the wafer
placed on each shelf. Preferably, the angle should be substantially
1 degree.
[0063] An actual solid angle of the light beam from the emitter 9a
is about 2 degree. If the emitter 9a and the detector 9b are
arranged so that the light beam from the emitter 9a to the detector
9b is parallel to the surface of the wafer placed on each shelf,
the light beam diffusely reflects on the surface of the wafer and
reach the detector 9b even though the direct light beam from the
emitter 9a is blocked by the wafer. In this case, ever though the
wafer should be detected, the detector 9b cannot detect the wafer
since the detector receives the diffuse reflection from the wafer.
Therefore, if the emitter 9a and the detector 9b are arranged with
an angle of about 1 degree to the surface of the wafer placed on
each shelf, it can avoid causing the diffuse reflection from the
wafer.
Second Embodiment
[0064] In Embodiment 1, a magnetic fluid seal is disposed in such a
state in which the rod 47 extends through the opposite end portions
of the through-hole in the fixing member 39, whereby dust produced
from the pivotally movable portion can be prevented from being
outputted to the outside to thereby further prevent the
contamination by the dust. Embodiment 2 will hereinafter be
described.
[0065] Magnetic fluid seals 48a and 48b attached to the opposite
end portions of the through-hole in the fixing member 39 in such a
state that the rod 47 extends therethrough. Each of the magnetic
fluid seal 48a and the magnetic fluid seal 48b is of structure in
which a magnetic member (e.g., a ferrite magnet) is sandwiched
between two annular thin plates. Further, when a magnetic fluid is
interposed between these plates, this magnetic fluid is held
between these plates by the magnetic force of the ferrite magnet,
and the held magnetic fluid is held in the gap with respect to an
object to be sealed by surface tension. As a result, film of the
magnetic fluid is forcibly forced on the magnetic fluid seals to
thereby achieve sealing. In the present apparatus, film of oil
including a magnetic material is disposed so as to be formed
between the peripheral surface of the rod 47 and the magnetic fluid
seals 48a and 48b. Thereby, dust produced from the rod 47 which is
a rotary shaft constituting the fulcrum 41 can be prevented.
[0066] Of course, Embodiment 2 can be applied to Embodiment 1, and
can be applied not only to the fulcrum 41 for opening and closing
the mapping frame 5 and the door 6, but also to the whole of the
pivotally movable portion. Accordingly, the magnetic fluid seal can
be applied to the whole of the pivotally movable portion in spite
of the fact that in the wafer processing apparatus, there is an air
flow flowing from the upper portion toward the lower portion of the
apparatus and that the first fulcrum and the second fulcrum are
located below the underside of the pod.
[0067] While the invention has particularly been shown and
described with respect to the preferred embodiments thereof, it
will be understood by those skilled in the art that the foregoing
and other changes in form and details can be made therein without
departing from the spirit and scope of the invention.
* * * * *