U.S. patent application number 11/740249 was filed with the patent office on 2007-11-15 for cassette conveyance method and cassette conveyance apparatus.
Invention is credited to Minoru Ametani, Isamu Kawashima, Hideo Kino, Hideshi Sato.
Application Number | 20070262276 11/740249 |
Document ID | / |
Family ID | 38468855 |
Filed Date | 2007-11-15 |
United States Patent
Application |
20070262276 |
Kind Code |
A1 |
Kawashima; Isamu ; et
al. |
November 15, 2007 |
CASSETTE CONVEYANCE METHOD AND CASSETTE CONVEYANCE APPARATUS
Abstract
A cassette conveyance apparatus (10) includes: a first
conveyance means (20) for conveying a first cassette (40) in a
horizontal and vertical direction; and a second conveyance means
(30) for conveying a second cassette (50) in a horizontal and
vertical direction. In the cassette conveyance apparatus (10), the
first and second cassettes are circulated between a predetermined
wafer accommodation position (P1), at which a wafer (2) is
accommodated in the cassette, and a predetermined cassette
replacement position (P0) at which a cassette accommodating a
plurality of wafers is replaced with an empty cassette. Due to the
foregoing, the wafers are continuously accommodated in the cassette
without stopping an operation of a pretreatment step.
Inventors: |
Kawashima; Isamu; (Tokyo,
JP) ; Sato; Hideshi; (Tokyo, JP) ; Kino;
Hideo; (Tokyo, JP) ; Ametani; Minoru; (Tokyo,
JP) |
Correspondence
Address: |
CHRISTIE, PARKER & HALE, LLP
PO BOX 7068
PASADENA
CA
91109-7068
US
|
Family ID: |
38468855 |
Appl. No.: |
11/740249 |
Filed: |
April 25, 2007 |
Current U.S.
Class: |
250/589 ;
414/217; 414/222.01 |
Current CPC
Class: |
H01L 21/67769
20130101 |
Class at
Publication: |
250/589 ;
414/222.01; 414/217 |
International
Class: |
B65H 5/00 20060101
B65H005/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 12, 2006 |
JP |
2006-133985 |
Claims
1. A cassette conveyance apparatus comprising: a first conveyance
means for conveying a first cassette in a horizontal and vertical
direction; and a second conveyance means for conveying a second
cassette in a horizontal and vertical direction, wherein the first
and the second cassettes are circulated by the first and second
conveyance means between a workpiece accommodation position, at
which a workpiece is accommodated in the cassette, and a cassette
replacement position at which the cassette accommodating a
plurality of workpieces is replaced with an empty cassette.
2. A cassette conveyance apparatus according to claim 1, the first
conveyance means including: a first horizontal rail; a first
horizontal slider sliding on the first horizontal rail; a first
vertical rail attached to the first horizontal slider; a first
vertical slider sliding on the first vertical rail; and a first
table, which is attached to the first vertical slider, on the top
face of which the first cassette is arranged, and the second
conveyance means including: a second horizontal rail arranged in
parallel with the first horizontal rail; a second horizontal slider
sliding on the second horizontal rail; a second vertical rail
attached to the second horizontal slider; a second vertical slider
sliding on the second vertical rail; and a second table, which is
attached to the second vertical slider, on the top face of which
the second cassette is arranged.
3. A cassette conveyance apparatus according to claim 1, wherein
the first table extends toward the second horizontal rail, the
second table extends toward the first horizontal rail, and the
first and the second table can be at least partially overlapped
with each other on a face vertical to the first and the second
horizontal rail.
4. A cassette conveyance apparatus according to claim 3, wherein
distances, by which the first and the second table extend from the
vertical sliders corresponding to the first and the second table,
are shorter than the distance between the first and the second
horizontal rail.
5. A cassette conveyance apparatus according to one of claims 2 to
4, wherein the lengths of the first and the second vertical rails
are set in such a manner that the second table and the second
cassette can pass under the first table when the first vertical
slider is located at the lowermost position of the first vertical
rail and when the second vertical slider is located at the
uppermost position of the second vertical rail.
6. A cassette conveyance apparatus according to one of claims 2 to
4, wherein the lengths of the first and the second vertical rails
are set at minimum values in such a manner that the second table
and the second cassette can pass under the first table when the
first vertical slider is located at the lowermost position of the
first vertical rail and when the second vertical slider is located
at the uppermost position of the second vertical rail.
7. A cassette conveyance method comprising: a first accommodation
step in which a workpiece is accommodated in a first cassette at a
workpiece accommodation position for accommodating the workpiece in
the cassette; a first conveyance step in which the first cassette
is conveyed to a cassette replacement position at which a cassette
accommodating a plurality of workpieces is replaced with an empty
cassette and in the first conveyance step the second cassette
replaced at the cassette replacement position is conveyed to the
workpiece accommodation position; a second accommodation step in
which the workpiece is accommodated in the second cassette at the
workpiece accommodation position; and a second conveyance step in
which the second cassette accommodating a plurality of workpieces
is conveyed to the cassette replacement position and in the second
conveyance step the first cassette replaced at the cassette
replacement position is conveyed to the workpiece accommodation
position, wherein the first accommodation step, the first
conveyance step, the second accommodation step and the second
conveyance step are repeated.
8. A cassette conveyance method according to claim 7, wherein the
cassette is lowered by a predetermined distance each time the
cassette accommodates one workpiece at the workpiece accommodation
position, the cassette accommodating all of the plurality of
workpieces is located at a position lower than the workpiece
accommodating position, and in the first and the second conveyance
step, the one cassette of the first and the second cassettes
conveyed from the cassette replacement position to the workpiece
accommodation position passes above the other cassette conveyed
from the workpiece accommodation position to the cassette
replacement position.
9. A cassette conveyance method according to claim 8, wherein the
first and the second conveyance step include a process in which the
other cassette is raised.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a cassette conveyance
method for conveying cassettes, in which a plurality of wafers are
accommodated, in the field of manufacturing semiconductor devices.
The present invention also relates to a cassette conveyance
apparatus in which this cassette conveyance method is executed.
[0003] 2. Description of the Related Art
[0004] In the field of manufacturing semiconductors, there is a
tendency for large-sized wafers to be used year after year.
Further, in order to enhance the packing density, the wafer
thickness has been reduced. In order to reduce the wafer thickness,
back-grinding the surfaces of wafers is carried out. After
back-grinding is finished, a dicing tape is adhered to the back
surface of each wafer, so that the wafer can be integrated with a
mount frame into one body.
[0005] After that, a surface protective film, which has been
previously adhered onto the front surface of the wafer, is peeled.
Then, an ID number formed on the surface of each wafer is read.
After a bar code label corresponding to the ID number is adhered,
the wafer is accommodated in a cassette (refer to Japanese Patent
Application No. 2006-35259). Japanese Unexamined Patent Publication
No. 5-82625 discloses a technique in which a wafer, which has
already been subjected to predetermined processing although the
wafer is not integrated with a mount frame into one body, is
accommodated in a cassette.
[0006] FIGS. 6a to 6c are sectional schematic illustrations showing
actions of cassettes of the prior art, for example described in
Japanese Patent Application No. 2006-35259. As shown by arrow a1 in
FIG. 6a, a first cassette 400 is conveyed to a predetermined
position p0 in a processing device 100 through an opening portion
111 of the processing device 100 by a conveyance means (not
shown).
[0007] On the other hand, a wafer 2, on which final processing has
been conducted in a processing unit 150 of the processing device
100, for example, on which a bar code label has been adhered, is
accommodated in a first cassette 400 by a robot hand (not shown) as
shown by arrow a2. The first cassette 400 is lowered by a
predetermined distance each time one wafer 2 is accommodated in the
first cassette, and the next wafer 2 is successively accommodated
in the first cassette. The first cassette 400, in which a
predetermined number of wafers 2 are accommodated, is lowered to a
predetermined position. Then, the first cassette 400 is conveyed in
the horizontal direction and temporarily stocked at first stock
position p1 (refer to arrow a3).
[0008] Next, as shown in FIG. 6b, a second cassette 500 is conveyed
to predetermined position p0 through an opening portion 111. In the
same manner as that of the first cassette 400, in the second
cassette 500, the wafers 2 are accommodated. Then, the first
cassette 400 is conveyed to second stock position p2 located at a
lower position of first stock position p1 (refer to arrows a4 and
a5).
[0009] After the cassettes 400, 500 are charged at two stock
positions p1, p2 respectively, the processing unit 150 is stopped.
Then, as shown by arrow a7 in FIG. 6c, the first cassette 400 is
discharged outside the processing device 100 through the opening
portion 111. As shown by arrow a8, the second cassette 500 is
discharged outside the processing device 100 in the same manner as
that of the first cassette 400. After these two cassettes 400, 500
have been discharged, a new empty cassette is conveyed to a
predetermined position p0. After the processing unit 150 is started
again, the wafer 2 is accommodated in the new cassette in the same
manner as that described above.
[0010] However, in the case where the wafers 2 are accommodated in
both the first cassette 400 and the second cassette 500 in the
cassette conveyance action of the prior art shown in FIGS. 6a and
6c, before the new cassette is used, it is necessary to stop the
processing unit 150 and pick up the two cassettes 400, 500 from the
processing device 100.
[0011] That is, it is necessary to stop the operation of the
processing unit 150 during a period of time from when the wafers 2
have been accommodated in the second cassette 500 to when the new
cassette is conveyed to predetermined position P0. Accordingly,
processing of the wafers 2 is delayed due to the stoppage of
operation of the processing unit 150. Recently, in the field of
manufacturing semiconductors, high production capacity is required.
Therefore, it is desirable to avoid the delay of the processing
time described above.
[0012] The present invention has been accomplished in view of the
above circumstances. It is an object of the present invention to
provide a cassette conveyance method in which wafers can be
continuously accommodated in a cassette without stopping an
operation of a pretreatment step. It is another object of the
present invention to provide a cassette conveyance apparatus in
which this cassette conveyance method is executed.
SUMMARY OF THE INVENTION
[0013] In order to accomplish the above object, according to the
first embodiment, a cassette conveyance apparatus comprises: a
first conveyance means for conveying a first cassette in the
horizontal and the vertical direction; and a second conveyance
means for conveying a second cassette in the horizontal and the
vertical direction, wherein the first and the second cassette are
circulated by the first and the second conveyance means between a
workpiece accommodation position, at which a workpiece is
accommodated in the cassette, and a cassette replacement position
at which the cassette accommodating a plurality of workpieces is
replaced with an empty cassette.
[0014] In the first embodiment, when one cassette is arranged at
the workpiece accommodation position, the other cassette is
replaced at the cassette replacement position. After accommodation
has finished for one cassette, a new cassette, which has been
replaced, is conveyed to the workpiece accommodation position, so
that workpieces, for example, wafers can be continuously
accommodated. Due to the foregoing, without stopping an operation
of a pretreatment step, the workpieces, for example, wafers can be
continuously accommodated.
[0015] According to the second embodiment, as in the cassette
conveyance apparatus of the first embodiment, the first conveyance
means includes: a first horizontal rail; a first horizontal slider
sliding on the first horizontal rail; a first vertical rail
attached to the first horizontal slider; a first vertical slider
sliding on the first vertical rail; and a first table, which is
attached to the first vertical slider, on the top face of which the
first cassette is arranged, and the second conveyance means
includes: a second horizontal rail arranged in parallel with the
first horizontal rail; a second horizontal slider sliding on the
second horizontal rail; a second vertical rail attached to the
second horizontal slider; a second vertical slider sliding on the
second vertical rail; and a second table, which is attached to the
second vertical slider, on the top face of which the second
cassette is arranged.
[0016] That is, in the second embodiment, it is possible to compose
the first and the second conveyance means by a relatively simple
configuration.
[0017] According to the third embodiment, as in the second
embodiment, the first table extends toward the second horizontal
rail, the second table extends toward the first horizontal rail,
and the first and the second table can be at least partially
overlapped with each other on a face vertical to the first and the
second horizontal rail.
[0018] That is, in the third embodiment, it is possible to reduce
the width of the cassette conveyance apparatus by a portion where
the first and the second table are overlapped with each other.
[0019] According to the fourth embodiment, as in the third
embodiment, distances, by which the first and the second table
extend from the vertical sliders corresponding to the first and the
second table, are a little shorter than the distance between the
first and the second horizontal rail.
[0020] Therefore, according to the fourth embodiment, the width of
the cassette conveyance apparatus can be minimized.
[0021] According to the fifth embodiment, as in one of the second
to the fourth embodiments, lengths of the first and the second
vertical rail are set in such a manner that the second table and
the second cassette can pass through under the first table when the
first vertical slider is located at the lowermost position of the
first vertical rail and when the second vertical slider is located
at the uppermost position of the second vertical rail.
[0022] Therefore, according to the fifth embodiment, the cassettes
are conveyed in such a manner that the one cassette can pass
through above the other cassette. Therefore, it is possible to
convey the first and the second cassette at the same time.
[0023] According to the sixth embodiment, as in one of the second
to the fourth embodiments, lengths of the first and the second
vertical rail are set at the minimum values in such a manner that
the second table and the second cassette can pass through under the
first table when the first vertical slider is located at the
lowermost position of the first vertical rail and when the second
vertical slider is located at the uppermost position of the second
vertical rail.
[0024] Therefore, according to the sixth embodiment, lengths of the
first and the second vertical rail can be minimized.
[0025] According to the seventh embodiment, a cassette conveyance
method comprises: a first accommodation step in which a workpiece
is accommodated in a first cassette at a workpiece accommodation
position for accommodating the workpiece in the cassette; a first
conveyance step in which the first cassette is conveyed to a
cassette replacement position at which a cassette accommodating a
plurality of workpieces is replaced with an empty cassette and in
the first conveyance step the second cassette replaced at the
cassette replacement position is conveyed to the workpiece
accommodation position; a second accommodation step in which the
workpiece is accommodated in the second cassette at the workpiece
accommodation position; and a second conveyance step in which the
second cassette accommodating a plurality of workpieces is conveyed
to the cassette replacement position and in the second conveyance
step the first cassette replaced at the cassette replacement
position is conveyed to the workpiece accommodation position,
wherein the first accommodation step, the first conveyance step,
the second accommodation step and the second conveyance step are
repeated.
[0026] That is, in the seventh embodiment, when one cassette is
being arranged at the workpiece accommodation position, the other
cassette is replaced at the cassette replacement position. After
the accommodation has been finished for one cassette, the new
cassette, which has been replaced, is conveyed to the workpiece
accommodation position, for example, so that the workpiece
continuously accommodate the wafer. Due to the foregoing, without
stopping an operation of the pretreatment step, for example, the
workpieces, wafers can be continuously accommodated in the
cassette.
[0027] According to the eighth embodiment, as in the seventh
embodiment, the cassette is lowered by a predetermined distance
each time the cassette accommodates one workpiece at the workpiece
accommodation position, the cassette accommodating all of the
plurality of workpieces is located at a position lower than the
workpiece accommodating position, and in the first and the second
conveyance steps, one cassette of the first and the second cassette
conveyed from the cassette replacement position to the workpiece
accommodation position passes above the other cassette conveyed
from the workpiece accommodation position to the cassette
replacement position.
[0028] Therefore, according to the eighth embodiment, one cassette
can pass above the other cassette. Therefore, it is possible to
reduce the size needed for executing the cassette conveyance
method. Due to the foregoing, it is possible to convey both
cassettes at the same time.
[0029] According to the ninth embodiment, as in the eighth
embodiment, the first and the second conveyance steps include a
process in which the other cassette is raised.
[0030] That is, the ninth embodiment is advantageous especially
when the workpiece accommodation position and the cassette
replacement position are located on substantially the same
plane.
[0031] These and other objects, features and advantages of the
present invention will be more apparent in light of the detailed
description of exemplary embodiments thereof as illustrated by the
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] In the drawings:
[0033] FIG. 1 is a side view showing a cassette conveyance
apparatus according to the present invention;
[0034] FIG. 2 is a plan view showing the cassette conveyance
apparatus shown in FIG. 1;
[0035] FIG. 3 is a partial enlarged front view showing the cassette
conveyance apparatus shown in FIG. 1;
[0036] FIG. 4 is a flow chart showing an operation of the cassette
conveyance apparatus of the present invention;
[0037] FIG. 5a is a first sectional schematic illustration showing
an operation of the cassette conveyance apparatus of the present
invention;
[0038] FIG. 5b is a second sectional schematic illustration showing
an operation of the cassette conveyance apparatus of the present
invention;
[0039] FIG. 5c is a third sectional schematic illustration showing
an operation of the cassette conveyance apparatus of the present
invention;
[0040] FIG. 5d is a fourth sectional schematic illustration showing
an operation of the cassette conveyance apparatus of the present
invention;
[0041] FIG. 6a is a first sectional schematic illustration showing
a conveyance operation of conveying a cassette of the prior
art;
[0042] FIG. 6b is a second sectional schematic illustration showing
a conveyance operation of conveying a cassette of the prior art;
and
[0043] FIG. 6c is a third sectional schematic illustration showing
a conveyance operation of conveying a cassette of the prior
art.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0044] Referring to the accompanying drawings, an embodiment of the
present invention will be explained below. Similar reference
numerals are used to indicate similar parts in the following
drawings. In order to facilitate the understanding, the scale of
these drawings has been changed appropriately.
[0045] FIG. 1 is a side view showing a cassette conveyance
apparatus according to the present invention. FIGS. 2 and 3 are a
plan view and a partial enlarged front view showing the cassette
conveyance apparatus shown in FIG. 1, respectively. As shown in
these drawings, the cassette conveyance apparatus 10 of the present
invention includes: a first conveyance means 20 for conveying a
first cassette 40 in the vertical and the horizontal direction; and
a second conveyance means 30 for conveying a second cassette 50 in
the vertical and the horizontal direction. These conveyance actions
are conducted by motors 29, 39 arranged in the first conveyance
means 20 and the second conveyance means 30.
[0046] As shown in FIG. 1, on the housing 11 of the cassette
conveyance apparatus 10, a lid portion 12 is pivotably arranged
around a shaft portion 12a. As shown in FIG. 1, a processing unit
15 is arranged on the right of the cassette conveyance apparatus
10. The processing unit 15 can conduct predetermined processing on
a wafer 2, for example, the processing unit 15 can adhere a bar
code label (not shown) on the wafer 2. However, a processing unit
15 for conducting another processing may be arranged.
[0047] In the present invention, a back surface of the wafer 2
supplied to the processing unit 15 is ground. Therefore, the
thickness of the wafer 2 is greatly reduced. On the back surface of
the wafer 2, a dicing tape 3 is adhered, and the wafer 2 is
integrated with a mount frame 58 into one body. When the wafer 2 is
supplied to the processing unit 15, a surface protective film,
which was adhered to the front surface of the wafer 2, has already
been peeled. In this connection, in an embodiment not shown in the
drawing, a wafer 2, which is not integrated with the mount frame
58, but subjected to another processing, may be supplied to the
processing unit 15.
[0048] As shown in FIG. 3, the first conveyance means 20 includes a
first horizontal rail 21 extending in the horizontal direction. A
first horizontal slider 22 slides on the first horizontal rail 21.
To the first horizontal slider 22, a first vertical rail 23
extending in the vertical direction is attached. On this first
vertical rail 23, a first vertical slider 24 is slid. A bracket
type first table 25, on the top face 26 of which a first cassette
40 can be arranged, extends in the horizontal direction from the
first vertical slider 24.
[0049] In the same manner, the second conveyance means 30 includes
a second horizontal rail 31 extending parallel to the first
horizontal rail 21. A second horizontal slider 32 slides on the
second horizontal rail 31. To the second horizontal slider 32, a
second vertical rail 33 extending in the vertical direction is
attached. On this second vertical rail 33, a second vertical slider
34 is slid. A bracket type second table 35, on the top face 36 of
which a second cassette 50 can be arranged, extends in the
horizontal direction from the second vertical slider 34.
[0050] As can be seen from FIGS. 2 and 3, the first table 25
extends in a direction from the first vertical slider 24 to the
second horizontal rail 31, and the second table 35 extends in a
direction from the second vertical slider 34 to the first
horizontal rail 21. The sizes of the first 25 and second tables 35
are sufficiently large for arranging the first 40 and second
cassettes 50, respectively, on the top faces of the tables.
[0051] In the embodiment shown in FIGS. 2 and 3, the distances of
the extensions of the first 25 and second tables 35 are a little
shorter than the distance between the first rail 21 and second
horizontal rails 31. Accordingly, in the present embodiment, the
width of the cassette conveyance apparatus 10 can be minimized.
[0052] As can be seen from FIG. 3, when the first table 25 is
located at the uppermost position of the first vertical rail 23 and
the second table 35 is located at the lowermost position of the
second vertical rail 33, a gap, in which the second cassette 50 can
pass through, is formed between the first table 25 and the second
table 35. This gap shown in FIG. 3 is the minimum size necessary
for the second cassette 50 to pass through the gap. In this case,
the lengths of the first rail 23 and second vertical rails 33 are
minimized. That is, in this case, the height of the cassette
conveyance apparatus 10 can be minimized.
[0053] As shown in FIG. 3, on the inner faces of the respective
side portions of the first 40 and second cassette 50, a plurality
of slits 41, 51, which are opposed to each other, are formed. The
distance between the slits, which are opposed to each other, is
substantially the same as the outer diameter 58 of the mount frame
58, which is integrated with the wafer 2. However, in the case of
an embodiment in which the mount frame 58 is not used, the distance
between the slits, which are opposed to each other, is
substantially the same as the outer diameter of the wafer 2.
[0054] Referring to FIG. 1 again, the first cassette 40 is
positioned at the uppermost position of the first vertical rail 23.
As shown in the drawing, this position P1 is adjacent to the
processing unit 15. At this position P1, the wafer 2, which has
been processed by the processing unit 15, is conveyed from the
processing unit 15 to the first cassette 40 by a robot hand (not
shown in the drawing) and accommodated into the slit 41 formed in
the first cassette 40. Position P1 at which the wafer 2 can be
accommodated in the cassette will be referred to as the wafer
accommodation position P1 hereinafter.
[0055] In FIG. 1, the second cassette 50 is positioned at the
uppermost position of the second vertical rail 33. This position P0
is at the same height as that of the wafer accommodation position
P1 and located on the left of the wafer accommodation position P1.
As can be seen from FIG. 1, the cassette arranged at this position
P0 can be picked up from the cassette conveyance apparatus 10 when
the lid portion 12 is opened. Then, another cassette (not shown)
can be set on the table. This position P0, at which the cassette
can be replaced with another cassette, will be referred to as
cassette replacement position P0 hereinafter.
[0056] Although not shown in FIG. 1 and the other drawings, the
cassette conveyance apparatus 10 includes a control unit connected
to the first conveyance means 20 and the second conveyance means
30. The control unit controls the cassette conveyance apparatus 10
according to the flow of operation as showing FIG. 4, and also
according to the operation of the cassette conveyance apparatus 10
as shown in FIGS. 5a to 5d.
[0057] Referring to FIG. 4 and FIGS. 5a to 5d, the operation of the
cassette conveyance apparatus 10 of the present invention will be
explained below. In this connection, at the initial stage of
operation of the cassette conveyance apparatus 10, as shown in FIG.
1, both the first 40 and second cassettes 50 are empty and
respectively arranged at the wafer accommodation position P1, and
the cassette replacement position P0. Further, the lid portion 12
of the housing 11 is closed.
[0058] In step 101 shown in FIG. 4, the processing unit 15 and the
related robot arm are started so as to convey the wafer 2 from the
processing unit 15 to the first cassette 40. The wafer 2 is
accommodated in the lowermost slit 41 in the first cassette 40.
[0059] The first vertical slider 24 of the first table 25, which
supports the first cassette 40, is lowered along the first vertical
rail 23 by a distance corresponding to one slit 41 and stops at the
position. Due to the foregoing, the wafer 2, which has been
successively processed by the processing unit 15, is accommodated
in the slit 41, which is arranged just above the lowermost
slit.
[0060] Then, the first table 25 is lowered by a distance
corresponding to one slit 41 and the next wafer 2 is accommodated
(refer to arrow A1 in FIG. 5a). By repeating this operation, a
plurality of wafers 2 are successively accommodated in a plurality
of slits 41 in the first cassette 40. When the wafers 2 are
accommodated in all of the slits 41 in step 102, the accommodation
operation in the first cassette 40 is finished.
[0061] Since the first cassette 40 is lowered by a predetermined
distance each time one wafer 2 is accommodated in the first
cassette 40, when the accommodation operation is finished in the
first cassette 40, the first cassette 40 is located at a position
lower than the second table 35 of the second cassette 50 located at
the cassette replacement position P0 (refer to FIG. 5a).
[0062] As can be seen from FIG. 3, in the specification of this
patent application, the region containing the cassette located at
the uppermost position of the first vertical rail 23 (or the second
vertical rail 33) is referred to as upper region Z1. Further, the
region located at a position lower than the table of the cassette
located in upper region Z1 is referred to as lower region Z0.
[0063] Next, as shown by arrow A2 in FIG. 5b, the first horizontal
slider 22 is slid to the left along the first horizontal rail 21.
Due to the foregoing, the first cassette 40 is retracted to the
lower region Z0 (step 103). That is, the first cassette 40 is
conveyed away from the wafer accommodation position P1.
[0064] At the same time, as shown by arrow A3, the second
horizontal slider 32 is slid to the right along the second
horizontal rail 31. Due to the foregoing, the second cassette 50 is
advanced to upper region Z1. That is, in this case, the second
cassette 50 is conveyed from the cassette replacement position P0
to the wafer accommodation position P1.
[0065] When the second cassette 50 has arrived at the wafer
accommodation position P1, the first cassette 40 is located right
below the cassette replacement position P0. As shown by arrow A4 in
FIG. 5c, the first vertical slider 24 of the first cassette 40 is
raised along the first vertical rail 23 (step 104). Due to the
foregoing, the first cassette 40 can be conveyed to the cassette
replacement position P0.
[0066] After that, the lid portion 12 is opened and the first
cassette 40 is picked up from the cassette conveyance apparatus 10.
Another empty cassette 40 (not shown) is arranged on the second
table 35. The first cassette 40 (or the second cassette 50) may be
manually picked up and replaced by an operator. Alternatively, the
first cassette 40 may be automatically picked up and replaced by a
robot.
[0067] After the first cassette 40 has been raised in step 104 or
simultaneously when the first cassette 40 has been raised in step
104, the second cassette 50 starts accommodating the wafer 2 in
step 105. In this case, in the same manner as that of the first
cassette 40, each time a wafer 2 is accommodated, the second
cassette 50 is lowered by a predetermined distance (refer to arrow
A5 in FIG. 5d).
[0068] When all of the plurality of wafers 2 are accommodated in
the second cassette 50, that is, when the second cassette 50
finishes accommodating the wafers 2, the second cassette 50 is
lowered to lower region Z0.
[0069] Although not shown in the drawing, the second horizontal
slider 32 is slid to the left along the second horizontal rail 31
in step 107. Due to the foregoing, the second cassette 50 is
retracted in lower region Z0. At the same time, the first
horizontal slider 22 is slid to the right along the first
horizontal rail 21. Due to the foregoing, the second cassette 50 is
advanced in upper region Z1. Then, in step 108, the second vertical
slider 34 is raised along the second vertical rail 33 and conveyed
to the cassette replacement position P0. In this way, the cassette
is replaced with another second cassette 50.
[0070] Next, the program is returned to step 101 and wafers 2 are
successively accommodated in the first cassette 40, which has
arrived at the wafer accommodation position P1. After that, steps
101 to 108 described above are repeated.
[0071] In the present invention, the first cassette 40 and the
second cassette 50 are alternately circulated between the wafer
accommodation position P1 and the cassette replacement position P0.
When one cassette is arranged at the wafer accommodation position
P1, the other cassette can be picked up and/or replaced at the
cassette replacement position P0. When the other cassette is
arranged at the wafer accommodation position P1, one cassette can
be picked up and/or replaced at the cassette replacement position
P0.
[0072] In the cassette conveyance apparatus 10 of the present
invention, the wafer 2 can always be accommodated in either of the
two cassettes. Accordingly, in the present invention, it is not
necessary to stop the processing unit 15, which is the pretreatment
step. Therefore, in the present invention, there is no delay in
time since the processing unit 15 is not stopped. Consequently, it
is possible to exhibit a high production capacity.
[0073] In the embodiment described above, both the wafer
accommodation position P1 and the cassette replacement position P0
are located in upper region Z1. However, in the case where either
the wafer accommodation position P1 or the cassette replacement
position P0 is located at another position, for example, in the
case where either the wafer accommodation position P1 or the
cassette replacement position P0 is located in lower region Z0, the
same effect can be obtained by using the cassette conveyance
apparatus 10 of the present invention.
[0074] Further, in the embodiment described above, for example, the
first conveyance means 20 includes: a first horizontal rail 21, a
first horizontal slider 22, a first vertical rail 23, a first
vertical slider 24 and a first table 25. However, another
conveyance means capable of conveying the first cassette 40 (and
the second cassette 50) in the horizontal and the vertical
direction may be employed. The above case is included in the scope
of the present invention.
[0075] Furthermore, in the embodiment explained above referring to
the drawings, region Z1, in which one cassette is conveyed, is
located at a position higher than region Z0 in which the other
cassette is conveyed. However, regions Z1 and Z0, in which the
cassette is conveyed, may be located on the same plane. In this
case, the second cassette 50 is shown on the right or the left of
the first cassette 40, which is being conveyed in FIG. 3. This case
is also included in the scope of the present invention.
[0076] In the embodiment explained above, the cassette, in which
the wafer 2 integrated with the mount frame 58 is accommodated, is
conveyed. However, the cassette conveyance apparatus and the
cassette conveyance method of the present invention can be applied
to a case in which the cassette for accommodating only the wafer 2
is conveyed. In other words, the cassette conveyance apparatus of
the present invention may be incorporated into another apparatus.
For example, the cassette conveyance apparatus of the present
invention may be incorporated into a adhering device in which a
surface protective tape is adhered on a surface of the wafer 2.
Alternatively, the cassette conveyance apparatus of the present
invention may be incorporated into a peeling device in which a
surface protective tape adhered onto the surface of the wafer 2 is
peeled.
[0077] Although the invention has been shown and described with
exemplary embodiments thereof, it should be understood by those
skilled in the art that the foregoing and various other changes,
omissions and additions may be made therein and thereto without
departing from the scope of the invention.
* * * * *