U.S. patent application number 09/804233 was filed with the patent office on 2001-08-16 for method and apparatus for dry-in, dry-out polishing and washing of a semiconductor device.
Invention is credited to Aoki, Riichirou, Ishikawa, Seiji, Okumura, Katsuya, Tsujimura, Manabu, Yajima, Hiromi.
Application Number | 20010014572 09/804233 |
Document ID | / |
Family ID | 27580466 |
Filed Date | 2001-08-16 |
United States Patent
Application |
20010014572 |
Kind Code |
A1 |
Okumura, Katsuya ; et
al. |
August 16, 2001 |
Method and apparatus for dry-in, dry-out polishing and washing of a
semiconductor device
Abstract
A polishing apparatus includes an arrangement of a plurality of
units to deal with various operations and a robot having at least
one arm. The plurality of units are disposed around the robot and
include a loading unit for receiving thereon a, e.g. dry, workpiece
to be polished, a polishing system including at least one polishing
unit for polishing the workpiece, a washing system and a drying
system at least including one washing unit for washing and drying
the polished workpiece, and an unloading unit for receiving thereon
a resultant clean and dry polished workpiece.
Inventors: |
Okumura, Katsuya;
(Yokohama-shi, JP) ; Aoki, Riichirou; (Tokyo,
JP) ; Yajima, Hiromi; (Kanagawa-ken, JP) ;
Ishikawa, Seiji; (Yokohama-shi, JP) ; Tsujimura,
Manabu; (Yokohama-shi, JP) |
Correspondence
Address: |
WENDEROTH, LIND & PONACK, L.L.P.
2033 "K" Street N.W., Suite 800
Washington
DC
20006
US
|
Family ID: |
27580466 |
Appl. No.: |
09/804233 |
Filed: |
March 13, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09804233 |
Mar 13, 2001 |
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09233039 |
Jan 20, 1999 |
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09233039 |
Jan 20, 1999 |
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08767060 |
Dec 16, 1996 |
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5885138 |
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08767060 |
Dec 16, 1996 |
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08309193 |
Sep 20, 1994 |
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5616063 |
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Current U.S.
Class: |
451/41 ;
348/E5.108; 348/E5.113 |
Current CPC
Class: |
B24B 55/12 20130101;
F24F 3/167 20210101; B24B 37/345 20130101; H01L 21/67778 20130101;
H01L 21/67161 20130101; B24B 51/00 20130101; H01L 21/67028
20130101; H03M 13/39 20130101; H01L 21/67167 20130101; H01L
21/67219 20130101; B24B 27/0023 20130101; H01L 21/67745 20130101;
H01L 21/67057 20130101; B08B 1/04 20130101; H01L 21/67046 20130101;
H04N 5/455 20130101; H04N 21/426 20130101; B24B 37/04 20130101 |
Class at
Publication: |
451/41 |
International
Class: |
B24B 001/00; B24B
007/19 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 21, 1993 |
JP |
259396/1993 |
Nov 29, 1994 |
JP |
319289/1994 |
Dec 6, 1994 |
JP |
330209/1994 |
Dec 6, 1994 |
JP |
330210/1994 |
Dec 28, 1994 |
JP |
339165/1994 |
Dec 28, 1994 |
JP |
339166/1994 |
Dec 28, 1994 |
JP |
339167/1994 |
Claims
What is claimed is:
1. An apparatus for polishing and then washing a semiconductor
wafer, said apparatus comprising: an enclosing structure capable of
containing and preventing an atmosphere within said enclosing
structure from escaping therefrom to exterior thereof; a loading
unit for receipt of a semiconductor wafer to be polished; a
polishing system within said enclosing structure for polishing the
semiconductor wafer to form a polished semiconductor wafer; a
washing system within said enclosing structure for washing the
polished semiconductor wafer to form a clean polished semiconductor
wafer; a drying system within said enclosing structure for drying
the clean polished semiconductor wafer to form a clean and dry
polished semiconductor wafer; an unloading unit for receiving the
clean and dry polished semiconductor wafer; and at least one robot
for transferring the semiconductor wafer after said loading unit
receives the semiconductor wafer and before said unloading unit
receives the clean and dry polished semiconductor wafer.
2. An apparatus as claimed in claim 1, wherein said loading unit
and said unloading unit are separate.
3. An apparatus as claimed in claim 1, wherein said loading unit
and said unloading unit are integrated into a single unit.
4. An apparatus as claimed in claim 1, wherein said washing system
includes plural washing stations operable to achieve plural washing
operations.
5. An apparatus as claimed in claim 4, wherein said plural washing
operations include a primary washing operation and a secondary
washing operation.
6. An apparatus as claimed in claim 1, further comprising a rinsing
device for rinsing the polished semiconductor wafer at a first
position that is upstream of and separate from a second position at
which is located said primary washing station.
7. An apparatus as claimed in claim 1, wherein said clean and dry
polished semiconductor wafer is transferred with at least one first
mechanism that is discrete from at least one second mechanism
employed to transfer said polished semiconductor wafer.
8. An apparatus as claimed in claim 7, wherein said at least one
robot comprises a first robot comprising said at least one first
mechanism and a second robot comprising said at least one second
mechanism.
9. An apparatus as claimed in claim 1, wherein said drying system
comprises a spin-dryer.
10. An apparatus as claimed in claim 1, wherein said enclosing
structure is a housing.
11. An apparatus for polishing and then washing a semiconductor
wafer, said apparatus comprising: a housing adapted for
installation in a clean room; a loading unit for receipt of a
semiconductor wafer to be polished; a polishing system within said
housing for polishing the semiconductor wafer to form a polished
semiconductor wafer; a washing system within said housing for
washing the polished semiconductor wafer to form a clean polished
semiconductor wafer, said washing system including plural washing
stations operable to achieve plural washing operations; a
spin-dryer within said housing for spin-drying the clean polished
semiconductor wafer to form a clean and dry polished semiconductor
wafer; and an unloading unit for receiving the clean and dry
polished semiconductor wafer.
12. An apparatus as claimed in claim 11, wherein said loading unit
and said unloading unit are separate.
13. An apparatus as claimed in claim 11, wherein said loading unit
and said unloading unit are integrated into a single unit.
14. An apparatus as claimed in claim 11, wherein said plural
washing operations include a primary washing operation and a
secondary washing operation.
15. An apparatus as claimed in claim 11, further comprising a
rinsing device for rinsing the polished semiconductor wafer at a
first position that is upstream of and separate from a second
position at which is located said primary washing station.
16. An apparatus as claimed in claim 11, wherein said clean and dry
polished semiconductor wafer is transferred with at least one first
mechanism that is discrete from at least one second mechanism
employed to transfer said polished semiconductor wafer.
17. An apparatus as claimed in claim 16, wherein said at least one
first mechanism comprises a first robot and said at least one
second mechanism comprises a second robot.
18. A method for manufacturing a semiconductor device using a
semiconductor wafer, said method comprising: introducing the
semiconductor wafer from the interior of a clean room into an
enclosing structure installed in said clean room; chemical
mechanical polishing said semiconductor wafer to form a polished
semiconductor wafer; washing said polished semiconductor wafer to
form a clean polished semiconductor wafer; spin-drying said clean
polished semiconductor wafer to form a clean and dry polished
semiconductor wafer; and removing said clean and dry polished
semiconductor wafer from said enclosing structure to said interior
of said clean room.
19. A method as claimed in claim 18, wherein said polishing
comprises conducting plural polishing operations by plural
polishing tables.
20. A method as claimed in claim 19, wherein said plural polishing
operations comprise plural sequential polishing operations
conducted on said semiconductor wafer by said plural polishing
tables.
21. A method as claimed in claim 18, wherein said washing comprises
conducting plural washing operations.
22. A method as claimed in claim 21, wherein said plural washing
operations include a primary washing operation and a secondary
washing operation.
23. A method as claimed in claim 18, further comprising rinsing
said polished semiconductor wafer before said washing.
24. A method as claimed in claim 23, comprising conducting said
rinsing at a first position and then conducting said washing at a
second position different from said first position.
25. A method as claimed in claim 18, comprising transferring said
clean and dry polished semiconductor wafer with at least one first
mechanism that is discrete from at least one second mechanism
employed to transfer said polished semiconductor wafer.
26. An apparatus as claimed in claim 25, wherein said at least one
first mechanism comprises a first robot and said at least one
second mechanism comprises a second robot.
27. A method as claimed in claim 18, wherein said washing and
spin-drying are carried out at a washing and drying station in a
washing unit.
28. A method as claimed in claim 18, wherein said washing and
spin-drying are carried out at a washing station and a drying
station which are separately provided.
29. A method as claimed in claim 18, wherein said polishing is
conducted by a polishing apparatus including a top ring for holding
said semiconductor wafer, and further comprising washing said top
ring after releasing said polished semiconductor wafer.
30. A method as claimed in claim 18, further comprising inverting
said semiconductor wafer before said polishing.
31. A method as claimed in claim 30, further comprising inverting
said polished semiconductor wafer after said polishing and before
said clean and dry polished semiconductor wafer is removed from
said enclosing structure.
32. A method as claimed in claim 18, wherein said semiconductor
wafer is taken out from a first container on a loading unit
containing semiconductor wafers to be polished, and said clean and
dry polished semiconductor wafer is put into a second container at
an unloading unit.
33. A method as claimed in claim 18, wherein said semiconductor
wafer is taken out from a container on a loading unit containing
semiconductor wafers to be polished, and said clean and dry
polished semiconductor wafer is returned into said container.
34. A method for manufacturing a semiconductor device using a
semiconductor wafer, said method comprising: introducing the
semiconductor wafer from the interior of a clean room into a
housing installed in said clean room; polishing said semiconductor
wafer to form a polished semiconductor wafer; washing said polished
semiconductor wafer at plural washing operations to form a clean
polished semiconductor wafer; spin-drying said clean polished
semiconductor wafer to form a clean and dry polished semiconductor
wafer; and removing said clean and dry polished semiconductor wafer
from said housing to said interior of said clean room.
35. A method as claimed in claim 34, wherein said plural washing
operations include a primary washing operation and a secondary
washing operation.
36. A method as claimed in claim 34, further comprising rinsing or
washing said polished semiconductor wafer before said washing.
37. A method as claimed in claim 34, comprising transferring said
clean and dry polished semiconductor wafer with at least one first
mechanism that is discrete from at least one second mechanism
employed to transfer said polished semiconductor wafer.
38. A method as claimed in claim 37, wherein said at least one
first mechanism comprises a first robot and said at least one
second mechanism comprises a second robot.
39. An apparatus for polishing and then washing a semiconductor
wafer, said apparatus comprising: an enclosing structure capable of
containing and preventing an atmosphere within said enclosing
structure from escaping therefrom to exterior thereof; a loading
unit for receipt of a semiconductor wafer to be polished; a
polishing system within said enclosing structure for polishing the
semiconductor wafer to form a polished semiconductor wafer; a
washing system within said enclosing structure for washing the
polished semiconductor wafer to form a clean polished semiconductor
wafer, said washing system including plural washing stations
operable to achieve plural washing operations and a transfer robot
for transferring said polished semiconductor wafer from a preceding
washing station to a subsequent washing station in said washing
stations; a spin-dryer within said enclosing structure for
spin-drying the clean polished semiconductor wafer to form a clean
and dry polished semiconductor wafer; and an unloading unit for
receiving the clean and dry polished semiconductor wafer.
40. An apparatus as claimed in claim 39, wherein said loading unit
and said unloading unit are separate.
41. An apparatus as claimed in claim 39, wherein said loading unit
and said unloading unit are integrated into a single unit.
42. An apparatus as claimed in claim 39, wherein said plural
washing operations include a primary washing operation and a
secondary washing operation.
43. An apparatus as claimed in clam 39, further comprising a
rinsing device for rinsing the polished semiconductor wafer at a
first position that is upstream of and separate from a second
position at which is located said preceding washing station.
44. An apparatus as claimed in claim 39, wherein said clean and dry
polished semiconductor wafer is transferred with at least one first
mechanism that is discrete from at least one second mechanism
employed to transfer said polished semiconductor wafer.
45. An apparatus as claimed in claim 44, wherein said at least one
robot comprises a first robot comprising said at least one first
mechanism and a second robot comprising said at least one second
mechanism.
46. An apparatus as claimed in claim 39, wherein said enclosing
structure is a housing.
47. An apparatus for polishing and then washing a semiconductor
wafer, said apparatus comprising: an enclosing structure capable of
containing and preventing an atmosphere within said enclosing
structure from escaping therefrom to exterior thereof; a loading
unit for receipt of a semiconductor wafer to be polished; a
polishing system within said enclosing structure for polishing the
semiconductor wafer to form a polished semiconductor wafer; a
washing system within said enclosing structure for washing the
polished semiconductor wafer to form a clean polished semiconductor
wafer; a drying system within said enclosing structure for drying
the clean polished semiconductor wafer to form a clean and dry
polished semiconductor wafer; an unloading unit for receiving the
clean and dry polished semiconductor wafer; and at least two robots
for transferring the semiconductor wafer after said loading unit
receives the semiconductor wafer before said unloading unit
receives the clean and dry polished semiconductor wafer, one of
said at least two robots being operable to transfer a wet polished
semiconductor wafer, and the other of said at least two robots
being operable to transfer a dry semiconductor wafer.
48. An apparatus as claimed in claim 47, wherein said washing
system includes plural washing stations operable to achieve plural
washing operations.
49. An apparatus as claimed in claim 48, wherein said plural
washing operations include a primary washing operation and a
secondary washing operation.
50. An apparatus as claimed in claim 47, further comprising a
rinsing device for rinsing the polished semiconductor wafer at a
first position that is upstream of and separate from a second
position at which is located a primary washing station.
51. An apparatus as claimed in claim 47, wherein said drying system
comprises a spin-dryer.
52. An apparatus as claimed in claim 47, wherein said enclosing
structure is a housing.
Description
[0001] This is a continuation of U.S. patent application Ser. No.
09/233,039, filed Jan. 20, 1999, which is a division of application
Ser. No. 08/767,060, filed Dec. 16, 1996, now U.S. Pat. No.
5,885,138, which is a Continuation-In-Part of application Ser. No.
08/309,193, filed Sep. 20, 1994, now U.S. Pat. No. 5,616,063, of
application Ser. No. 08/563,295, filed Nov. 28, 1995, now U.S. Pat.
No. 5,679,059, and of application Ser. No. 08/580,312, filed Dec.
28, 1995, now U.S. Pat. No. 5,827,110.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a polishing method and
apparatus, and more particularly to such a method and apparatus for
polishing a workpiece such as a semiconductor wafer. Further
particularly, the present invention relates to such a method and
apparatus wherein a workpiece to be polished and washed,
particularly a dry workpiece, is loaded into the apparatus, is
polished and then washed and dried therein, and wherein the
resultant clean and dry polished workpiece is transferred from the
apparatus. When a dry workpiece to be polished is loaded into the
apparatus and a clean and dry polished workpiece is transferred
from the apparatus, the method is referred to hereinafter as a
"dry-in, dry-out" method. Still further particularly, the present
invention relates to such a "dry-in, dry-out" method and apparatus
including a plurality of operating units disposed in an array or
cluster around at least one center robot having at least one robot
arm, and having a transfer structure including separate and
discrete transfer mechanisms including at least one first transfer
mechanism for transferring a dry workpiece into the apparatus and
for transferring the clean and dry polished workpiece from the
apparatus, and at least one second transfer mechanism for
transferring the workpiece between polishing and washing units of
the apparatus.
[0004] 2. Description of Related Art
[0005] Recent rapid progress in semiconductor device integration
demands smaller and smaller wiring patterns or interconnections and
also narrower spaces between interconnections which connect active
areas. One of the processes available for forming such
interconnections is photolithography. Although a photolithographic
process can form interconnections that are at most 0.5 .mu.m wide,
such process requires that surfaces on which pattern images are to
be focused by a stepper be as flat as possible because the depth of
focus of the optical system is relatively small.
[0006] It is therefore necessary to make the surfaces of
semiconductor wafers flat to enable use of photolithography. One
customary way of flattening the surfaces of semiconductor wafers is
to polish them with a polishing apparatus.
[0007] Conventionally, such a polishing apparatus has a single
function of polishing a semiconductor wafer. Therefore, in the case
of washing a semiconductor wafer after polishing, the semiconductor
wafer must be transferred or transported from the polishing
apparatus to a washing apparatus. Further, in the case of polishing
a semiconductor wafer again under different conditions after a
first polishing operation, the semiconductor wafer must be
transferred or transported from one polishing apparatus to another
polishing apparatus. In such cases, the semiconductor wafers are
manually transferred or transported by a movable container in which
they are immersed in water to keep them from drying during
transportation. However, since various apparatuses including a
polishing apparatus and a washing apparatus are independently
installed and the semiconductor wafers are transferred or
transported by the movable container containing water therein, it
is difficult to install the polishing apparatus, the washing
apparatus and the like in a clean room of a semiconductor
manufacturing plant and to automate completely various processes
including a polishing process and a washing process.
[0008] In order to solve the above problems, there has been
proposed an apparatus which has a polishing unit and a washing unit
provided in a common housing. Further, if necessary, a plurality of
polishing units can be provided in a common housing. In a polishing
apparatus which has a polishing unit and a washing unit, or a
plurality of polishing units in a common housing, it is conceivable
to construct a cluster type of polishing apparatus which integrates
a plurality of units including a polishing unit and a washing unit,
as employed in a semiconductor manufacturing process such as
etching or chemical vapor deposition (CVD).
[0009] However, in the case of constructing a cluster type of
polishing apparatus which integrates a plurality of units and
incorporates a universal transfer robot at a central position of
the units, it is necessary to handle both a dirty and wet
semiconductor wafer soiled with abrasive slurry or particles
generated by the polishing operation and a clean and dry
semiconductor wafer which is placed on a loading unit or an
unloading unit. Therefore, a conventional robot incorporated in a
cluster type of a semiconductor manufacturing processing apparatus
cannot be used in a cluster type of polishing apparatus because
such robot is not capable of handling separately both a clean
semiconductor wafer and a dirty semiconductor wafer. If such
conventional robot is incorporated into the polishing apparatus, a
washing process and a drying process of the robot or a robot arm
additionally are required, thus lowering throughput efficiency of
the apparatus. Further, when such robot or the robot arm is left
for a long time as it is, abrasive material or particles generated
by the polishing operation adhere to the robot or the robot arm,
resulting in contamination of subsequent semiconductor wafers or
respective units of the polishing apparatus.
SUMMARY OF THE INVENTION
[0010] Therefore, it is an object of the present invention to
provide an improved polishing method and apparatus wherein it is
possible to achieve polishing of a workpiece and then to achieve
washing and drying of the workpiece.
[0011] It is a further object of the present invention to provide
such a method and apparatus wherein workpieces to be polished that
are introduced to the apparatus are dry and wherein polished and
cleaned workpieces that are discharged from the apparatus also are
dry, wherein the method and apparatus operate according to a
dry-in, dry-out principle.
[0012] It is a yet further object of the present invention to
provide such a method and apparatus wherein it is possible to
overcome the above discussed and other prior art disadvantages and
to provide a much greater degree of manufacturing flexibility than
has been possible in the prior art.
[0013] It is an even still further object of the present invention
to provide such a polishing method and apparatus employing a
cluster type arrangement of a plurality of units that perform
various operations, as well as a transfer structure including
exclusive means for handling a clean semiconductor wafer and
exclusive means for handling a dirty semiconductor wafer. Thus, a
transfer mechanism or mechanisms that handle a dry semiconductor
wafer to be loaded into the apparatus and that handle a clean and
dry semiconductor wafer that has been polished and then washed and
dried and that is discharged from the apparatus are exclusive,
discrete and separate from a transfer mechanism or mechanisms that
transfer semiconductor wafers among polishing and washing systems
of the apparatus. Thus, dry semiconductor wafers are loaded into
the apparatus, and dry semiconductor wafers that have been polished
and washed are transferred from the apparatus.
[0014] In accordance with one aspect of the present invention,
there is provided a method and apparatus wherein a workpiece to be
polished is transferred from a loading unit to a polishing system,
whereat the workpiece is polished to form a polished workpiece. The
polished workpiece is transferred from the polishing unit to a
washing unit defining washing and drying systems. The workpiece is
washed and then dried at the washing unit to form a clean and dry
polished workpiece. The thus clean and dry polished workpiece then
is transferred from the washing unit to an unloading unit. In
accordance with a further feature of the present invention, the
workpiece to be polished is transferred in a dry condition from the
loading unit to the polishing unit.
[0015] According to another aspect of the present invention, there
is provided a polishing method and apparatus for polishing a
surface of a workpiece and washing the workpiece which has been
polished. A universal transfer robot has at least one arm for
transferring the workpiece. A plurality of units are disposed
around the universal transfer robot and include a loading unit for
receiving thereon the dry workpiece to be polished, a polishing
system including at least one polishing unit for polishing the
workpiece which is transferred from the loading unit, a washing
system and a drying system defined by at least one washing unit for
washing and drying the workpiece which has been polished and an
unloading unit for receiving thereon the resultant washed and dried
polished workpiece. A transfer structure includes an exclusive
transfer mechanism that transfers a clean workpiece and another
exclusive transfer mechanism that transfers a dirty workpiece. The
loading unit, the unloading unit, the polishing unit and the
washing unit are disposed around the universal transfer robot. A
workpiece, i.e. a dry workpiece, is picked up from the loading unit
by the universal transfer robot, transferred to the polishing unit,
and polished by the polishing unit. After the polishing operation,
the thus dirty workpiece is transferred from the polishing unit to
the washing unit by another exclusive transfer mechanism and is
washed and dried by the washing unit. After such washing and drying
operations, the resultant clean and dry polished workpiece is
transferred from the washing unit to the unloading unit by the
universal transfer robot.
[0016] According to a further aspect of the present invention, the
universal transfer robot has an arm for exclusively handling a
clean workpiece and an arm for exclusively handling a dirty
workpiece. The loading unit, the unloading unit, the polishing unit
and the washing unit are disposed around the universal transfer
robot. A workpiece, e.g. a dry workpiece, is picked up from the
loading unit by the arm for exclusively handling a clean workpiece
of the universal transfer robot, transferred to the polishing unit,
and polished by the polishing unit. After such polishing operation,
the thus dirty workpiece is transferred from the polishing unit to
the washing unit by the arm for exclusively handling a dirty
workpiece of the universal transfer robot, and is washed and dried
by the washing unit. After such washing and drying operations, the
resultant clean and dry polished workpiece is transferred from the
washing unit to the unloading unit by the arm for exclusively
handling a clean workpiece of the universal transfer robot
[0017] According to a still further aspect of the present
invention, the transfer structure includes two universal transfer
robots each having at least one arm for transferring the workpiece,
and the plurality of units are disposed around the two universal
transfer robots. One of the universal transfer robots transfers a
clean workpiece and the other of the universal transfer robots
transfers a dirty workpiece. The loading unit, the unloading unit,
the polishing unit and the washing unit are disposed around the two
universal transfer robots. A workpiece, e.g. a dry workpiece, is
picked up from the loading unit by the universal transfer robot for
exclusively handling a clean workpiece, transferred to the
polishing unit, and polished by the polishing unit. After such
polishing operation, the thus dirty workpiece is transferred from
the polishing unit to the washing unit by the universal transfer
robot for exclusively handling a dirty workpiece, and is washed and
dried by the washing unit. After such washing and drying
operations, the resultant clean and dry polished clean workpiece is
transferred from the washing unit to the unloading unit by the
universal transfer robot for exclusively handling a clean
workpiece.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a schematic plan view of an embodiment of a
polishing apparatus according to the present invention;
[0019] FIG. 2A is a schematic plan view of part of the polishing
apparatus according to the present invention;
[0020] FIG. 2B is a schematic plan view of a washing unit in the
polishing apparatus according to the present invention;
[0021] FIG. 3 is a cross-sectional view taken along line A1-A2 of
FIG. 2A;
[0022] FIG. 4 is a cross-sectional view taken along line B1-B2 of
FIG. 2A;
[0023] FIG. 5 is a cross-sectional view taken along line
D1-C3-C2-C1 of FIG. 2A;
[0024] FIG. 6 is a cross-sectional view taken along line D1-D2 of
FIG. 2A;
[0025] FIG. 6A is a view similar to FIG. 6, but showing a modified
washing unit;
[0026] FIG. 7 is a schematic plan view of a second embodiment of a
polishing apparatus according to the present invention;
[0027] FIG. 8 is a schematic plan view of a third embodiment of a
polishing apparatus according to the present invention,
[0028] FIG. 9 is a schematic plan view of a fourth embodiment of a
polishing apparatus according to the present invention;
[0029] FIG. 10 is a schematic plan view of a fifth embodiment of a
polishing apparatus according to the present invention; and
[0030] FIG. 11 is a schematic plan view of a sixth embodiment of a
polishing apparatus according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] Each of the embodiments will be described with reference to
polishing a workpiece in the form of a semiconductor wafer.
[0032] A first embodiment of a polishing apparatus according to the
present invention will be described below with reference to FIG. 1.
As shown in FIG. 1, the polishing apparatus has a center robot 10
having arms 10-1 and 10-2 at a central part thereof. The center
robot 10 constitutes a universal transfer robot. Around the center
robot 10 and in the area that can be accessed by the arm 10-1,
there are provided a loading unit 11 on which a semiconductor wafer
S to be polished, e.g. a dry semiconductor wafer, is placed, an
unloading unit 12 on which a clean and dry semiconductor wafer S
which has been polished and then cleaned and dried is placed, a
polishing system including polishing units 13 and 14 each for
polishing the semiconductor wafer S, and a washing system and
drying system including washing unit 15 for washing and drying the
polished semiconductor wafer S.
[0033] The polishing unit 13 has a polishing head supporting am
13-3, a turntable 13-4 and a top ring rotatably provided on the
polishing head supporting an 13-3. The polishing unit 14 has a
polishing head supporting arm 14-3, a turntable 14-4 and a top ring
rotatably provided on the polishing head supporting arm 14-3. An
abrasive cloth is attached to each of respective upper surfaces of
the turntables 13-4 and 14-4. Each of the polishing head supporting
arms 13-3 and 14-3 constitutes an exclusive transferring device for
transferring the semiconductor wafer S from a loading position
13-1, 14-1 of the polishing unit to the turntable 13-4, 14-4.
Further, each of the polishing head supporting arms 13-3 and 14-3
constitutes an exclusive transferring device for transferring the
polished semiconductor wafer S from the polishing unit 13, 14 to
the washing unit 15. The polishing apparatus has a table 16 for a
dressing tool 16-1 for dressing the abrasive cloth on the turntable
13-4 and a table 17 for a dressing tool 17-1 for dressing the
abrasive cloth on the turntable 14-4.
[0034] In the polishing apparatus, the semiconductor wafer S to be
polished is picked up under vacuum by the arm 10-1 of the center
robot 10, is inverted to dispose a surface thereof to be polished
downwardly, and is transferred to the loading position 13-1 of the
polishing unit 13. The top ring of the polishing head supporting
arm 13-3 holds the semiconductor wafer S and presses the
semiconductor wafer S against the abrasive cloth attached to the
upper surface of the turntable 13-4. At this time, the turntable
13-4 is rotated, and the top ring is rotated about its own axis and
swung on the turntable 13-4 by the polishing head supporting arm
13-3, whereby the semiconductor wafer S is polished.
[0035] After such polishing operation, the polished semiconductor
wafer S is transferred to a loading position 15-1 of the washing
unit 15 by the polishing head supporting arm 13-3. The polishing
head supporting arm 13-3 which releases the semiconductor wafer S
at the loading position 15-1 chucks dressing tool 16-1 on the table
16 and presses the dressing tool 16-1 against the abrasive cloth on
the turntable 13-4, thereby dressing such abrasive cloth. This
dressing operation may be performed by an exclusive dressing
mechanism.
[0036] The semiconductor wafer S which has been transferred to the
loading position 14-1 of the polishing unit 14 by the arm 10-1 of
the center robot 10 also is held by the top ring of the polishing
head supporting arm 14-3 and pressed against the abrasive cloth
attached to the upper surface of the turntable 14-4. After such
polishing operation, the polished semiconductor wafer S is
transferred to a loading position 15-2 of the washing unit 15.
Further, the polishing head supporting arm 14-3 which releases the
semiconductor wafer S chucks dressing tool 17-1 on the table 17 and
presses the dressing tool 17-1 against the abrasive cloth on the
turntable 14-4, thereby dressing such abrasive cloth.
[0037] The polished semiconductor wafer S transferred to the
loading position 15-1 or the loading position 15-2 is washed and
dried in the washing unit 15, and then is transferred to an
unloading position 15-3. The polished semiconductor wafer S thus is
cleaned and dried and is transferred from the unloading position
15-3 to the unloading unit 12 by the arm 10-2 of the center robot
10. All of the above described operations are performed entirely
automatically.
[0038] Next, the polishing unit 14 and the washing unit 15 will be
described in detail with reference to FIGS. 2A through 6A that
further illustrate the embodiment of the present invention shown in
FIG. 1. However, FIGS. 2A-6A do not illustrate a dressing tool and
a table therefor, but rather illustrate an exclusive dressing
mechanism 15-11.
[0039] As shown in FIG. 2A, the semiconductor wafer S placed on the
loading unit 11 is picked up by the arm 10-1 of the center robot
10, inverted to direct its surface to be polished downwardly by a
reversing mechanism 11-2, and transferred to the loading position
14-1 of the polishing unit 14. As shown in FIG. 3, the
semiconductor wafer S is held under vacuum by the top ring 14-5
provided at the forward end of the polishing head supporting arm
14-3 and moved above the turntable 14-4. Thereafter, the top ring
14-5 is lowered, and the semiconductor wafer S held by the top ring
14-5 is pressed against the abrasive cloth on the turntable 14-4,
whereby the semiconductor wafer S is polished. The turntable 14-4
is rotated by a motor 14-6 through a timing belt 14-7 (see FIG. 4).
As shown in FIG. 5, after such polishing operation, the arm 14-3
and top ring 14-5 put the semiconductor wafer S into a washing
receptacle 15-4 which is standing by at an opening of the loading
position 15-2 of the washing unit 15, and top ring 14-5 is washed
by cleaning solvent. During such washing operation, the opening of
the loading position 15-2 is closed by a shutter 15-5. The top ring
14-5 which releases the semiconductor wafer S is washed at the
loading position by a washing mechanism of the washing unit 15.
[0040] After such washing operation, the semiconductor wafer S is
moved in direction a (FIG. 5) and transferred to a reversing or
inverting mechanism 15-6 by which the semiconductor wafer S is
inverted to dispose its surface which has been polished upwardly
and supplied to a primary washing station 15-7. A primary washing
operation is carried out using cleaning solvent such as pure water
at the primary washing station 15-7. Thereafter, the semiconductor
wafer S is picked up by a transfer robot 15-8 in the washing unit
15, moved in directions of arrows b and c and fed to a secondary
washing station 15-9. A secondary washing operation is carried out
using cleaning solvent such as pure water at the secondary washing
station 15-9.
[0041] After the secondary washing operation, the semiconductor
wafer S is dried. Thus, the workpiece may be dried in the manner
shown schematically in FIG. 6, wherein after the secondary washing
operation at station 15-9, the wafer is dried by a drying system,
in this embodiment spin-dried by spinning a wafer holding station
at high speed, for example by a motor. This spinning is indicated
schematically by the circular arrow in FIG. 6. The thus washed and
dried polished wafer then is picked up by the arm 10-2 of the
center robot 10, moved in directions of arrows d and e as shown in
FIG. 6, and transferred to the unloading unit 12. As shown in FIG.
2A, dressing mechanism 15-11 dresses the abrasive cloth on the
turntable 14-4. The dressing mechanism 15-11 has a rotating brush
15-12 as shown in FIG. 3.
[0042] An alternative drying arrangement is shown schematically in
FIG. 6A. Thus, the washing and drying system include a washing unit
having a separate secondary washing station 15-9A and a separate
drying station 15-9B. After secondary washing in station 15-9A, the
thus cleaned wafer is transferred, for example by arm 10-2 of robot
10, to drying station 15-9B whereat the wafer is dried. The thus
cleaned and dried polished wafer then is transferred by arm 10-2 of
robot 10 and moved further in direction e to unloading unit 12.
[0043] The drying arrangements shown schematically in FIGS. 6 and
6A may be in accordance with the structures shown in Ser. No.
08/563,295 and Ser. No. 08/580,312, the disclosures of which hereby
are incorporated herein by reference.
[0044] In accordance with the present invention, the entire
apparatus is compact in size and therefore may be positioned in
enclosing structure, e.g. a housing unit 30, shown schematically in
FIGS. 6 and 6A. When housing unit 30 is provided with a necessary
exhaust duct system, the polishing apparatus can be installed in a
clean room without lowering the cleanliness thereof, without
requiring a large amount of space in the clean room, and at any
suitable and flexibly movable position within the clean room.
[0045] According to the first embodiment, the polishing apparatus
comprises a center robot 10 having arms 10-1 and 10-2 and
constituting a universal transfer robot for transferring the
semiconductor wafer S to the respective units, a plurality of units
disposed around the center robot 10 and including a loading unit 11
for receiving thereon the semiconductor wafer S to be polished, an
unloading unit 12 for receiving thereon the clean and dry
semiconductor wafer S which has been polished, polishing units 13
and 14 each for polishing the semiconductor wafer S, and a washing
unit for washing and drying the polished semiconductor wafer S. The
polishing apparatus further comprises a polishing head supporting
arm 13-3 having a top ring for transferring the semiconductor wafer
S between two adjacent units and a polishing head supporting arm
14-3 having a top ring for transferring the semiconductor wafer S
between two adjacent units. A transfer structure includes center
robot 10 that handles clean and dry semiconductor wafers S, and the
polishing head supporting arms 13-3 and 14-3 that handle dirty and
wet semiconductor wafers S Particularly, center robot 10 handles a,
e.g. dry, semiconductor wafer S from the loading unit 11 to the
loading position of the particular polishing unit, and center robot
10 also handles a clean and dry polished semiconductor wafer S from
the unloading position 15-3 of the washing unit 15 to the unloading
unit 12 On the other hand, the polishing head supporting arms 13-3
and 14-3 handle dirty and wet semiconductor wafers S from the
respective polishing units to the washing unit.
[0046] The center robot 10 has the arm 10-1 which is exclusively
used for loading the semiconductor wafer to be polished and the arm
10-2 which is exclusively used for unloading the clean and dry
semiconductor wafer which has been polished. This arrangement is
preferable in a case where the degree of cleanliness of the
semiconductor wafer S transferred from the loading unit 11 is
different from that of the semiconductor wafer S transferred to the
unloading unit 12.
[0047] Next, a further embodiment of the polishing, apparatus
according to the present invention will be described below with
reference to FIG. 7. The parts shown in FIG. 7 which are identical
to those of FIG. 1 are denoted by identical reference numerals. The
polishing apparatus has a center robot 10 having arms 10-1 and 10-2
at a central part thereof. Around the center robot 10 and in an
area that can be accessed by the arm 10-1, there are provided a
loading unit 11, an unloading unit 12, polishing units 13 and 14, a
washing unit 15, and auxiliary spaces 18 and 19 for accommodating
additional units, in a hexagonal arrangement
[0048] In the auxiliary spaces 18 and 19 are installed, for
example, thickness meters for measuring a thickness of the
semiconductor wafer. In such case, the, e.g. dry, semiconductor
wafer S is held by the arm 10-1 of the center robot 10 and fed to
the thickness meter in the auxiliary space 18. Before a polishing
operation, the thickness of the semiconductor wafer S is measured
by the thickness meter, and then the wafer S is transferred to the
loading position 13-1 of the polishing unit 13.
[0049] After a polishing operation, the polished semiconductor
wafer S is transferred to the washing unit 15 in the same manner as
in the first embodiment and is washed and dried in the washing unit
15. After such washing operation, the clean and dry polished
semiconductor wafer S is fed to the thickness meter in the
auxiliary space 18 by the arm 10-1 of the center robot. After
measuring the thickness of the semiconductor wafer S which has been
polished, the clean and dry polished semiconductor wafer S is
transferred to the unloading unit 12 by the arm 10-2 of the center
robot 10.
[0050] FIG. 8 shows another embodiment of the polishing apparatus
according to the present invention. The parts shown in FIG. 8 which
are identical to those of FIG. 1 are denoted by identical reference
numerals. Around a center robot 10 having arms 10-1 and 10-2 and in
the area that can be accessed thereby, there are provided, in a
hexagonal arrangement, a loading unit 11, an unloading unit 12, a
polishing system including two polishing units 13 and a polishing
unit 14, a washing unit 15 provided between the polishing unit 14
and the unloading unit 12. This arrangement is preferable in the
case where the polishing unit 13 requires twice as much time as the
polishing unit 14 to polish a wafer.
[0051] In this case, the transfer of the semiconductor wafer S from
the polishing units 13 to the washing unit 15 and the transfer of
the semiconductor wafer S from the polishing unit 14 to the washing
unit 15 are performed, not by the center robot 10, but by another
transfer means such as the polishing head supporting arms 13-3 and
14-3. However, the loading of the dry semiconductor wafer to the
polishing units 13 and 14 and the removal of the clean and dry
polished semiconductor wafer from the washing units 15 are
performed by the arms 10-1 and 10-2, respectively, of the center
robot 10. That is, the center robot 10 does not handle the
semiconductor wafer polished by the polishing units 13 and 14 so
that the arms 10-1 and 10-2 of the center robot 10 are not
contaminated by the semiconductor wafer which has been polished and
to which abrasive slurry adheres.
[0052] FIG. 9 shows a still further embodiment of the polishing
apparatus according to the present invention. The parts shown in
FIG. 9 which are identical to those of FIG. 1 are denoted by
identical reference numerals. The polishing apparatus is provided
with a transfer structure including center robot 10 having only one
arm 10-1. In the case of providing only the arm 10-1, the transfer
structure also includes exclusive transferring devices provided
between the polishing units 13 and 14, and between the polishing
units 13, 14 and the washing unit 15. This system is applicable to
a case where the degree of cleanliness of the dry semiconductor
wafer which is transferred from the loading unit 11 is
substantially the same as that of the clean and dry polished
semiconductor wafer which is transferred to the unloading unit
12.
[0053] FIG. 10 shows a still further embodiment of the polishing
apparatus according to the present invention. The parts shown in
FIG. 10 which are identical to those of FIG. 1 are denoted by
identical reference numerals. Around a center robot 10 having arms
and in the area that can be accessed by the arms, there are
provided in a hexagonal arrangement a loading unit 11, a polishing
system including four polishing units 13, 14, 21 and 22, and a
washing unit 15. An unloading unit 12 is disposed at the end of the
washing unit 15. Further, a storage unit 23 is disposed adjacent to
the loading unit 11 and the unloading unit 12. An automatic guided
vehicle 24 is employed to transfer a semiconductor wafer S which
has been polished form the storage unit 23 and to convey a
semiconductor wafer to be polished to the storage unit 23.
[0054] Loading of the semiconductor wafer S onto the polishing
units 13, 14, 21 and 22 and the washing unit 15 and removal of the
semiconductor wafer S from the loading unit 11 and the polishing
units 13, 14, 21 and 22 are carried out entirely by the center
robot 10. Further, the transfer of the semiconductor wafer from the
washing unit 15 to the unloading unit 12 is carried out by the
center robot 10. The center robot 10 of this embodiment forms the
transfer structure including an arm for exclusively handling, a
clean semiconductor wafer (hereinafter referred as clean wafer
handling arm) and an arm for exclusively handling a dirty
semiconductor wafer (hereinafter referred as dirty wafer handling
arm). The transfer of the, e.g. dry, semiconductor wafer from the
loading unit 11 to one of the polishing units 13, 14, 21 and 22 and
the transfer of the clean and dry polished semiconductor wafer from
the washing unit 15 to the unloading unit 12 are carried out by the
clean wafer handling arm, and the transfer of the semiconductor
wafer between the polishing units 13, 14, 21 and 22 and the
transfer of the polished semiconductor wafer from one of the
polishing units 13, 14, 21 and 22 to the washing, unit 15 are
carried out by the dirty wafer handling arm. For example, in the
case of using the center robot 10 of FIG. 1, the arm 10-1 serves as
the clean wafer handling arm and the arm 10-2 serves as the dirty
wafer handling, arm. This structure prevents as much as possible
the semiconductor wafer from being contaminated.
[0055] According to this embodiment, the polishing apparatus
comprises a center robot 10 having arms 10-11 and 10-2 and
constituting a universal transfer robot for transferring, a
semiconductor wafer S to the respective units, a plurality of units
disposed around the center robot 10 and including a loading unit 11
for receiving thereon the semiconductor wafer S to be polished,
e.g. a dry wafer, an unloading, unit 12 for receiving thereon the
clean and dry semiconductor wafer S which has been polished, a
polishing system including polishing units 13, 14, 21 and 22 each
for polishing the semiconductor wafer S and a washing, unit 15 for
washing and drying the semiconductor wafer S. The center robot 10
is provided with an arm exclusively for handling a clean
semiconductor wafer and an arm exclusively for handling a dirty
semiconductor wafer. The arm for exclusively handling a dirty
semiconductor wafer is washed by a washing mechanism provided in
the washing unit 15 after handling the dirty semiconductor
wafer.
[0056] FIG. 11 shows still another embodiment of the polishing
apparatus according to the present invention. The parts shown in
FIG. 11 which are identical to those of FIG. 1 are denoted by
identical reference numerals. In this embodiment, the polishing
apparatus comprises a transfer structure including a center robot
10A for exclusively handling a clean semiconductor wafer and a
center robot 10B for exclusively handling a dirty semiconductor
wafer. Further, the polishing apparatus comprises a polishing
system including two polishing units 13, 14 and a washing unit
15.
[0057] With the above structure, a, e.g. dry, semiconductor wafer S
is picked up from a loading unit 11 by the center robot 10A and
transferred thereby to a loading position 13-1 of the polishing
unit 13. After a polishing operation, the polished semiconductor
wafer S is picked up from the polishing unit 13 by the center robot
10B and transferred thereby to a loading position 15-1 of the
washing unit 15. After washing and drying operations by washing and
drying systems, the resultant clean and dry polished semiconductor
wafer S is picked up from a loading position 15-3 of the washing
unit 15 by the center robot 10A and transferred thereby to an
unloading unit 12. By the above manner, a polishing process and
washing and drying processes are carried out. A polishing operation
is conducted by the polishing unit 14 in the same manner as
described above.
[0058] According to this embodiment, the semiconductor wafers S are
polished simultaneously or at a certain time lag by the polishing
units 13 and 14, and each of the semiconductor wafers S polished by
the polishing units 13 and 14 is washed and dried by washing and
drying systems in the washing unit 15. That is, it is possible to
deal with two semiconductor wafers with one washing unit for every
two polishing units. Especially in the case where the cycle of the
washing unit, i.e. the time interval between washing of a preceding
semiconductor wafer and washing of a subsequent semiconductor
wafer, is sufficiently shorter than the time required to polish
semiconductor wafers, there is no downtime during the polishing
operations. Thus, the processing speed of the overall apparatus is
prevented from being lowered and the total system can be more
compact in size.
[0059] Further, the polishing units 13 and 14 can be set to polish
semiconductor wafers under different conditions and selected in
accordance with properties of the semiconductor wafers.
Furthermore, a semiconductor wafer can be polished by the polishing
unit 13, washed by the washing unit 15, and then polished by the
polishing unit 14. Thereafter, the semiconductor wafer S can be
washed and dried by the washing unit 15. That is, the semiconductor
wafer can be polished twice. Such polishing apparatus has auxiliary
spaces 18 and 19 as shown in FIG. 11.
[0060] According to this embodiment, the polishing apparatus
comprises two center robots 10A, 10B each constituting a universal
transfer robot for transferring a semiconductor wafer S to
respective units, a plurality of units disposed around the center
robots 10A and 10B and including a loading unit 11 for receiving
thereon a semiconductor wafer S to be polished, e.g. a dry wafer,
an unloading unit 12 for receiving thereon a clean and dry
semiconductor wafer S which has been polished, polishing units 13
and 14 each for polishing a semiconductor wafer S and a washing
unit 15 for washing and drying a semiconductor wafer S which has
been polished. The center robot 10A handles only a clean
semiconductor wafer, and the center robot 10B handles only a dirty
semiconductor wafer. The center robot 10B is washed by a washing
mechanism provided in the washing unit 15 after handling the dirty
semiconductor wafer
[0061] According to the above embodiments, since at least one
polishing unit for performing chemical/mechanical polishing and at
least one washing and drying unit are disposed around a center
robot, the entire system is compact in size. Therefore, by
providing an enclosing structure such as a housing unit (e.g. as
shown at 30 in FIG. 6, 6A) to cover the entire system and an
exhaust duct, the polishing apparatus can be installed in a clean
room without lowering the cleanliness thereof. Further, the amount
of space in the clean room required for installation of the
polishing apparatus can be reduced.
[0062] In the above embodiments, although the loading unit 11 and
the unloading unit 12 are provided separately, the loading unit 11
and the unloading unit 12 may be formed integrally. For example, in
the case where a semiconductor wafer is picked up from a basket
containing semiconductor wafers and is put into the same basket
after undergoing a polishing operation and washing and drying
operations, the loading unit and the unloading unit are formed
integrally.
[0063] The basket comprises a cassette which is placed on the
loading unit and/or the unloading unit. A semiconductor wafer may
be picked up from a cassette on the loading unit and the unloading
unit and may be put into the same cassette on the loading unit and
the unloading unit after undergoing a polishing operation and
washing and drying operations. Further, a semiconductor wafer may
be picked up from a cassette on the loading unit and may be put
into a cassette on the unloading unit after undergoing a polishing
operation and washing and drying operations.
[0064] The cassette which is placed on the loading unit and/or the
unloading unit may be in accordance with the structures shown in
Ser. No. 08/563,295 and Ser. No. 08/580,312, the disclosures of
which hereby are incorporated herein by reference.
[0065] According to the present invention, a cluster type of
polishing apparatus which integrates a plurality of units including
a polishing unit defining a polishing system and a washing and
drying unit defining washing and drying systems and which employs a
universal transfer robot can be constructed. The polishing
apparatus performs a series of processes including a polishing
operation and washing and drying operations while saving
installation space and improving processing speed by efficiently
combining a plurality of units including at least one polishing
unit and at least one washing and drying unit. In the case where
the time required for polishing is longer than the cycle time of
the washing and drying operations, the polishing system can include
a plurality of polishing units to polish a plurality of
semiconductor wafers and be associated washing and drying systems
formed in one washing and drying unit. On the contrary, in the case
where the cycle time of the washing and drying operations is longer
than the time required for polishing, the washing and drying
systems can be formed by a plurality of washing and drying units to
wash and dry a plurality of semiconductor wafers and be associated
with a polishing system in the form of one polishing unit. Further,
according to the present invention, one or more polishing
operations and one or more of each of washing and drying operations
can be fully automated and can be changed or modified easily.
[0066] Furthermore, according to the present invention, since the
transfer structure includes exclusive means for handling a clean
semiconductor wafer and exclusive means for handling a dirty
semiconductor wafer that are provided separately, contamination of
subsequent semiconductor wafers or of respective units of the
polishing apparatus caused by the dirty semiconductor wafer can be
prevented.
[0067] Although the present invention has been described and
illustrated with regard to specific features and embodiments
thereof, it is to be understood that the present invention is not
intended to be limited to such specifically described and
illustrated features and embodiments. Rather, various modifications
and changes to such specifically described and illustrated features
and embodiments as would be apparent to one of ordinary skill in
the art are contemplated as being within the scope of the present
invention.
* * * * *