U.S. patent application number 09/866114 was filed with the patent office on 2001-10-18 for system and method for transporting and sputter coating a substrate in a sputter deposition system.
Invention is credited to Lee, Ke Ling, Lee, Ken, Martinson, Robert M., Mazur, Mikhail.
Application Number | 20010030128 09/866114 |
Document ID | / |
Family ID | 24184978 |
Filed Date | 2001-10-18 |
United States Patent
Application |
20010030128 |
Kind Code |
A1 |
Lee, Ke Ling ; et
al. |
October 18, 2001 |
System and method for transporting and sputter coating a substrate
in a sputter deposition system
Abstract
A substrate handling system auxiliary to a plasma sputtering
system is described. The substrate handling system inserts an
unprocessed substrate (e.g., an optical disk), an inner mask, and
an outer mask into a loadlock of the sputtering system, and then
seals the access opening to the loadlock. The substrate and the
masks then are moved to a sputtering chamber where the substrate is
coated by sputtering. Subsequently, the substrate handling system
moves a processed substrate, and its accompanying inner mask and an
outer mask, from the loadlock to an external disk change station,
where the processed substrate is removed from the masks, which are
still gripped by the substrate handling system. Subsequently,
another unprocessed disk is placed on the inner mask and within the
outer mask, and the sequence repeats. The substrate handling system
only contacts the masks on surfaces thereof that are not subjected
to direct sputter deposition, so that the masks can be gripped
without causing particulate contamination. A coated surface of the
inner mask and outer mask has numerous asperities to trap sputtered
material and reduce contamination.
Inventors: |
Lee, Ke Ling; (Cupertino,
CA) ; Mazur, Mikhail; (San Francisco, CA) ;
Lee, Ken; (Mountain View, CA) ; Martinson, Robert
M.; (San Mateo, CA) |
Correspondence
Address: |
SKJERVEN MORRILL MACPHERSON LLP
25 METRO DRIVE
SUITE 700
SAN JOSE
CA
95110
US
|
Family ID: |
24184978 |
Appl. No.: |
09/866114 |
Filed: |
May 25, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09866114 |
May 25, 2001 |
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09547522 |
Apr 12, 2000 |
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6264804 |
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Current U.S.
Class: |
204/298.11 ;
204/192.12; 204/298.15 |
Current CPC
Class: |
C23C 14/566 20130101;
C23C 14/042 20130101 |
Class at
Publication: |
204/298.11 ;
204/298.15; 204/192.12 |
International
Class: |
C23C 014/34; C23C
014/35 |
Claims
1. A mask for use in a sputtering system wherein a substrate having
a central opening is to be coated with a material, said mask
comprising: a body having a central aperture at a first end
thereof, said body sized to be insertable into said central opening
in the substrate; and an annular head at the first end of said body
around said central aperture, said head extending away from the
central aperture.
2. The mask of claim 1, wherein a surface of the annular head
includes numerous asperities, said surface being oriented so as to
be exposed to direct sputter deposition.
3. The mask of claim 1, wherein an outer surface of said body
includes a means for capturing the substrate under said head.
4. A mask for use in a sputtering system wherein a substrate is to
be coated with a material, said mask comprising: a hollow body
having a central aperture and a vertically extending sidewall
bounding said aperture, said central aperture sized so that the
substrate can be horizontally disposed within said aperture; and a
lip at a first end of the body around said central aperture, said
lip extending toward said central aperture.
5. The mask of claim 4, wherein the sidewall includes an outer
surface, said outer surface having at least one groove therein,
6. The mask of claim 4, where the sidewall includes an outer
surface, and at least one flange extends outwardly from the outer
surface.
7. The mask of claim 4, wherein a surface of said lip includes
numerous asperities, said surface being oriented so as to be
exposed to direct sputter deposition.
8. A masking system for use in a sputtering system, wherein a
substrate having a central first aperture is to be coated with a
material, said masking system assembly comprising: an inner mask
and an outer mask; said inner mask including a first body having a
central second aperture at a first end thereof, said first body
sized to be insertable into said first aperture in the substrate,
and an annular head at the first end of said first body around said
second aperture, said head extending away from the second aperture;
and said outer mask including a hollow second body having a central
third aperture and a vertically extending sidewall bounding said
third aperture, said third aperture sized so that the substrate can
be horizontally disposed within said third aperture, and a lip at a
first end of the second body around said third aperture, said lip
extending toward said third aperture.
9. The masking system of claim 8, wherein at least one of said
annular head and said lip include a surface having numerous
asperities thereon, said surface being oriented so as to be exposed
to direct sputter deposition.
10. The masking system of claim 9, wherein said annular head and
said lip include a surface having numerous asperities thereon, said
surface being oriented so as to be exposed to direct sputter
deposition.
11. A substrate handling system auxiliary to a sputtering system,
said substrate handling system for handling a substrate, an inner
mask for masking a central portion of the substrate, and an outer
mask for masking a circumferential portion of the substrate, said
substrate handling system comprising: an inner mask gripper and an
outer mask gripper, wherein said inner mask gripper grips the inner
mask on a surface thereof that is not subjected to direct sputter
deposition, and the outer mask gripper grips the outer mask on a
surface thereof that is not subjected to direct sputter
deposition.
12. The substrate handling system of claim 11, further comprising:
at least one arm upon which an inner mask gripper and outer mask
gripper are mounted; and a lid sized so as to seal a loadlock
opening of said sputtering system when said inner mask gripper and
said outer mask gripper are within said opening.
13. The substrate handling system of claim 11, further comprising
an actuator, wherein actuation of said actuator operates both said
inner mask gripper and said outer mask gripper.
14. The substrate handling system of claim 11, further comprising
plurality of outer mask grippers for gripping an outer mask.
15. The substrate handling system of claim 11, wherein said inner
mask gripper includes at least one member that is adapted to be
inserted into an aperture of said inner mask and to grip said inner
mask within said aperture.
16. The substrate handling system of claim 11, wherein said outer
mask gripper includes a member that is adapted to engage a groove
in the outer mask.
17. The substrate handling system of claim 11, wherein the outer
mask gripper includes a member that is adapted to contact the outer
mask beneath an outward extension of said outer mask.
18. A method of handling a substrate assembly in association with a
sputtering system, said substrate assembly including a substrate,
an inner mask for masking a central portion of the substrate, and
an outer mask for masking a circumferential portion of the
substrate, said method comprising: selectively gripping said inner
mask on a surface thereof that is not subjected to direct sputter
deposition; and selectively gripping said outer mask on a surface
thereof that is not subjected to direct sputter deposition.
19. The method of claim 18, wherein the inner mask includes a body
having a first end and an aperture at said first end, and the inner
mask is gripped within said aperture.
20. The method of claim 18, wherein the outer mask includes a
hollow body having a vertically extending sidewall and the outer
mask is gripped on an outer surface of said sidewall.
21. The method of claim 20, wherein the inner mask includes a body
having a first end and an aperture at said first end, and the inner
mask is gripped within said aperture.
22. The method of claim 21, further comprising using a single
actuator to cause the gripping of the inner mask and the outer
mask.
23. The method of claim 18, wherein the inner mask and the outer
mask are gripped at a plurality of points.
24. The method of claim 18, further comprising covering an external
opening of a loadlock of the sputtering system.
25. A method of masking a substrate that is to be coated in a
sputtering system, said substrate having a central first aperture,
the method comprising: providing an inner mask having a first body
with a central second aperture at a first end thereof, said body
sized to be insertable into said first aperture in the substrate,
and an annular head at the first end of said first body around said
second aperture, said head extending away from the central
aperture; inserting the first body through said first aperture of
the substrate so that a portion of the first surface of the disk is
superimposed by the annular head.
26. The method of claim 25, further comprising: providing an outer
mask that includes a hollow second body having a central third
aperture and a vertically extending sidewall bounding said third
aperture, said third aperture sized so that the substrate can be
horizontally disposed within said third aperture, and a lip at a
first end of the second body around said third aperture, said lip
extending toward said third aperture; and inserting the substrate
horizontally into the third aperture of the second body so that a
peripheral portion of the substrate is superimposed by the lip.
27. The method of claim 26, further comprising trapping sputtered
material on a surface of at least one of the annular head and lip
that is exposed to direct sputter deposition.
28. A method of masking a substrate that is to be coated in a
sputtering system, said method comprising: providing an outer mask
that includes a hollow body having a central aperture and a
vertically extending sidewall bounding said aperture, said aperture
sized so that the substrate can be horizontally disposed within
said sidewall, and a lip at a first end of the body around said
aperture, said lip extending toward said aperture; and inserting
the substrate horizontally into the aperture of the body so that a
peripheral portion of the substrate is superimposed by the lip.
29. A method of sputter coating a substrate, said method
comprising: positioning a substrate assembly at a sputtering
station in a vacuum chamber, wherein said substrate assembly
includes a substrate having a central first aperture, an inner
mask, and an outer mask; said inner mask including a first body
having a central second aperture at a first end thereof, said first
body being within said first aperture in the substrate, and an
annular head at the first end of said first body around said second
aperture, said head superimposing a surface of the substrate; and
said outer mask including a hollow second body having a central
third aperture and a vertically extending sidewall bounding said
third aperture, and a lip at a first end of the second body around
said third aperture, wherein said substrate is horizontally
disposed within said third aperture and said lip superimposes a
circumferential portion of said substrate; and sputter depositing
material onto the surface of substrate, the annular head, and the
lip.
30. The method of claim 29, further comprising trapping sputtered
material on a surface of at least one of the annular head and lip.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 09/547,522, which was filed on Apr. 12, 2000, and is
incorporated herein by reference in its entirety. This application
also is related to U.S. patent application Ser. No. 09/547,986,
which was filed on Apr. 12, 2000, and is incorporated herein by
reference in its entirety.
FIELD OF THE INVENTION
[0002] This invention relates generally to a system for loading and
masking substrates in association with a sputter deposition
system.
BACKGROUND OF THE INVENTION
[0003] A conventional optical disk includes a plastic base upon
which layers of various materials, such as metals, alloys, or
dielectrics, are applied. One method of applying the layers of
materials is to use a sputter deposition process.
[0004] A conventional sputter deposition process is performed using
a plasma formed in a vacuum chamber of a sputter deposition system.
The plasma is generated by applying electric power to a low
pressure gas in the vacuum chamber. Ions originating within the
plasma bombard a target formed of a material that is to be
deposited on the optical disk. The bombarding ions eject material
from the target. The ejected material deposits in a layer on the
disk.
[0005] A conventional sputtering system known as the BALZERS.TM.
BIG SPRINTER.TM. is believed to include a loadlock between a main
vacuum chamber and a disk loader robot. The disk loader robot
includes two opposing arms, each of which includes an identical
disk holder. An external robot loads an unprocessed optical disk
(or other substrate) into the disk holder, and unloads a processed
disk from the disk holder. The disk loader robot rotates
180.degree., and thereby alternatively positions each disk holder
at the loadlock and the external robot.
[0006] During the sputtering operation, the two masks, one known as
an inner mask and one as an outer mask, prevent deposition on the
central and peripheral portions of the disk, respectively. The
inner mask consists of a solid cylindrical body with an annular
head attached to one end of the cylindrical body. At the outside of
the cylindrical body is a spring mechanism that traps the disk
under the annular head. The outer mask is in shape of a flat ring.
The disk holders and the carrier arm hold the masks using magnets.
The annular head of the inner mask and the surface of the outer
mask that faces in the same direction as the sputtered surface of
the disk both get a coating of the sputtered material. Magnetized
components of the disk holder and the carrier arm contact the
sputtered surfaces of the inner and outer masks during loading and
handling processes.
[0007] The sputter-coated inner and outer masks need to be replaced
periodically. To do this, the disk loader robot is rotated
90.degree., thereby placing the disk holder with the masks that are
to be replaced at a station dedicated to changing of the masks.
[0008] There are drawbacks to the above described system that
heretofore have not been resolved. First, contacting the sputtered
surfaces of the inner and outer masks dislodges sputtered material
from the masks, causing particulate contamination on the disk and
in the sputtering system. Second, the masks get hot in the vacuum
chamber, and have limited opportunities to cool. The hot masks can
cause heat damage to the surface of the disk. Third, the use of
magnets near the substrate to hold the masks affects the plasma,
thereby affecting the uniformity of the film. Fourth, the
sputtering system includes a station dedicated to changing of the
masks, which consumes valuable space in the machine.
SUMMARY OF THE INVENTION
[0009] The present invention overcomes the aforesaid shortcomings
of the prior art, while at the same time providing a high
throughput and reliable system for loading, unloading, handling,
and masking substrates, such as optical disks, that are to be
coated with a sputtered material. The surfaces of the masks that
are subjected to direct sputter deposition (i.e., the surfaces that
face in the same direction as the coated surface of the substrate)
are not handled, which avoids the particulate contamination seen in
the prior art system.
[0010] A sputtering system within the present invention includes a
substrate handling system. The substrate handling assembly moves
individual unprocessed disks (i.e., disks to be sputter coated)
between a disk change station, which is external to the sputtering
system, and a loadlock of the sputtering system. The substrate
handling assembly moves individual processed disks (i.e., coated
disks) between the loadlock and the disk change station. An inner
mask and an outer mask accompany each unprocessed disk from the
external disk change station, through the sputtering system, and
back to the disk change station.
[0011] The substrate handling system includes one or more arms. At
the end of each arm is a disk and mask handling assembly, which is
called an "end effector" herein. In one embodiment, the end
effector comprises a lid that fits over an access opening to the
loadlock. The end effector also includes an inner mask gripper and
an outer mask gripper. The inner mask gripper grips the inner mask,
and the outer mask gripper grips the outer mask.
[0012] The inner mask is generally mushroom shaped and fits in a
hole in the center portion of the disk. Unlike the prior art inner
mask, however, the inner mask of the present invention has a
central cylindrical opening that is accessed through the annular
head. The inner mask gripper grips the inner mask on a sidewall
surface within the cylindrical opening that is not subjected to
direct sputter deposition.
[0013] The outer mask has a hollow vertically-extending body with a
central opening that is sized so that a disk can be horizontally
disposed within the central opening. A lip at the top of the body
superimposes a circumferential portion of the disk. The outer mask
gripper grips the outer mask on an outer surface of a
vertically-extending sidewall of the body of the outer mask. The
gripped surface is not subjected to direct sputter deposition.
[0014] In one embodiment, the substrate handling system operates by
positioning an end effector that is gripping an inner mask and an
outer mask at the external disk change station. An unprocessed disk
is placed and centered on the inner mask and within outer mask. The
substrate handling system moves the end effector to the loadlock,
places the unprocessed disk and masks into the loadlock, and seals
the access opening to the loadlock with the lid. The end effector
pushes the inner mask and outer mask onto a substrate transfer tray
positioned in the loadlock. The masks are released by the end
effector. The disk and its accompanying inner and outer masks then
move on the tray to a sputtering station. Subsequently, after a
tray having a processed disk and inner and outer masks is moved
into the loadlock, the load lock is vented, and the end effector at
the loadlock grips the inner and outer masks on unsputtered
surfaces thereof, thereby capturing the processed disk. The
substrate handling system moves the end effector to the disk change
station, where the processed disk is removed from the inner and
outer masks. The cycle subsequently repeats. The design of the
system allows high throughput loading and unloading of the
disks.
[0015] Further features and advantages of the invention will become
apparent in view of the drawings and detailed description of the
exemplary embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a cross-sectional side view of a substrate
handling system mounted on a sputtering system.
[0017] FIG. 2 is a simplified top plan view an alternative
substrate handling system having three arms.
[0018] FIG. 3 is a cross-sectional side view of an inner mask.
[0019] FIG. 4 is a cross-sectional side view of an alternative
inner mask.
[0020] FIG. 5 is a cross-sectional side view of an outer mask.
[0021] FIG. 6 is a cross-sectional side view of an alternative
outer mask.
[0022] FIG. 7 is a cross-sectional side view of an end
effector.
[0023] FIG. 8 is a perspective view of a rotary actuated outer mask
gripper.
[0024] FIG. 9A is a simplified top plan view of an end effector
having four rotary actuated outer mask grippers.
[0025] FIG. 9B is a simplified top plan view of an end effector
having one rotary actuated outer mask gripper and a belt.
[0026] FIG. 10 is a cross-sectional side view of a portion of an
alternative outer mask gripper for use with an outer mask.
[0027] FIG. 11 is a cross-sectional side view of an end effector
having an alternative outer mask gripper.
[0028] FIGS. 12a-12f are cross-sectional side views of stages in
the operation of substrate handling system.
DETAILED DESCRIPTION
[0029] FIG. 1 illustrates portions of an embodiment of a sputtering
system within the present invention. Sputtering system 20 sputters
layers of material onto the surface of a substrate using a plasma
formed in each of several sequential sputtering stations. The disks
and their accompanying inner and outer masks move from station to
station on a carousel. In the example embodiments described herein,
the substrate is an optical disk, but the type of substrate may
vary. Other features that may be part of sputtering system 20 are
disclosed in a commonly-assigned co-pending U.S. patent application
entitled "Magnetic Array for Sputtering System," Ser. No.
09/499,092, which was filed on Feb. 4, 2000, and is incorporated
herein by reference in its entirety.
[0030] Sputter system 20 includes a loadlock 24 that is used for
loading and unloading optical disks. A substrate handling system 21
is mounted to sputtering system 20 adjacent to loadlock 24. In this
embodiment, substrate handling system 21 includes two opposing arms
26 on a shaft 23 that rotates and moves vertically. The number of
arms can vary, however, as is discussed below. Handling system 21
loads unprocessed disks into loadlock 24 and unloads processed
disks from loadlock 24 through access opening 24A in loadlock 24.
This loading and unloading process is repeated over and over by
handling system 21.
[0031] An end effector 28A is present at the end of one arm 26 of
substrate handling system 21, and an end effector 28B is attached
to the opposing arm 26. Each end effector 28A, 28B includes an
inner mask gripper and an outer mask gripper. When handling system
21 rotates, end effectors 28A and 28B are moved between loadlock 24
and the external disk change station. A conventional electric motor
23A rotates and lifts arms 26 and shaft 23.
[0032] The number of arms on substrate handling system 21 can vary.
At a minimum, handling system 21 has one arm 26 that supports a
single end effector. FIG. 2 is a simplified top plan view of
alternative handling system 21-1 that includes three arms 26, which
respectively support identical end effectors 28A, 28B, and 28C.
When such a system is in use, end effector 28A may be positioned at
loadlock 24 (FIG. 1), end effector 28B may be at an external
station where processed disks are removed from end effector 28B,
and end effector 28C may be at an external station where
unprocessed disks are placed on end effector 28C. Rotation of
substrate handling system 21-1 moves each arm to the next station.
The methods used at the external disk change station to remove
processed disks from the end effector and to load unprocessed disks
onto the end effector may vary.
[0033] Each end effector 28A, 28B of FIG. 1 includes a lid 32 that
is located vertically between arm 26 and the inner mask gripper and
the outer mask gripper. During the loading and unloading process,
lid 32 is placed over opening 24A in loadlock 24. When lid 32 is
placed over opening 24A, lid 32 closes the opening and forms a
vacuum seal. An 0-ring seal may be provided around opening 24A or
on lid 32 to help form the gas tight seal.
[0034] FIG. 3 is a cross-sectional view of a first embodiment of an
inner mask 42. Inner mask 42 is generally mushroom shaped, and
includes an annular head 43 integrally connected to a first end of
a vertically-extending body 44. Body 44 has tapered sides 46 at an
opposite second end of body 44, and an orthogonal portion between
head 43 and tapered sides 46. Body 44 has a hollow cylindrical
aperture 45 that begins at the center of annular head 43 and
extends vertically into body 44. While the circumference of
aperture 45 is circular in this embodiment, the shape may vary. The
width and depth of central aperture 45 are sufficient to allow the
gripper fingers of the inner mask gripper to be inserted into
aperture 45 and achieve a firm grip on sidewall 45A of aperture 45.
A groove 47 is present around the orthogonal portion of the outer
surface of body 44 adjacent to aperture 45 and just below head 43.
A circular steel helical spring 48 is in groove 47 around body 44
and extends slightly beyond the sides of body 44.
[0035] An optical disk having a central aperture is captured on
inner mask 42 by inserting the tapered end of body 44 through the
aperture in the disk. Spring 48 deflects and allows the disk to
move upward toward head 43. Once the disk is past, spring 48
springs back, and captures the disk under head 43. Head 43 extends
over the surface that is to be coated, and thereby masks a central
circular portion of the disk during the sputtering process.
[0036] Inner mask 42 may be formed from aluminum, steel, or other
materials. All or part of the upper surface of annular head 43
(which is exposed to direct sputter deposition) has a rough surface
that includes many asperities 49 that can trap sputtered material.
Accordingly, material sputtered onto annular head 43 does not fall
on and contaminate the disk. The asperities may be provided by
spraying the upper surface of annular head 44 with an aluminum ARC
spray. The coating gets rougher going from the outer perimeter of
head 43 toward aperture 45.
[0037] FIG. 4 is an exploded view of an alternative inner mask 50.
Features similar to inner mask 42 of FIG. 3 have similar reference
numbers. Mask 50 is an assembly of several parts, including a first
body 51 having a vertically-extending cylindrical portion 51A and
an integral annular head 43 with asperities 49 thereon. Cylindrical
portion 51A has a central cylindrical aperture 45 with an inner
vertical sidewall 45A. A screw hole 52 is at the bottom of
cylindrical portion 51A. First body 51 is within a hollow second
body 53. The outer surface of second body 53 includes an orthogonal
upper portion 56 and a tapered lower portion 57. A strip 58 of
spring steel is between first body 51 and second body 53. A screw
54 extends through a hole 55 in second body 53 and a hole in strip
58 and engages the threads of screw hole 52 of first body 51. Screw
54 thus secures first body 51 to second body 52. Orthogonal portion
56 of second body 53 includes one or more (e.g., two or four)
chamfered openings in which a steel ball 59 is held. As a disk
passes up second body 53, the sidewall of the central aperture of
the disk contacts balls 59 and causes balls 59 to deflect inward.
After the disk moves past balls 59, spring 58 pushes balls 59
outward, which causes the disk to be captured under head 43.
[0038] FIG. 5 is a cross-sectional side view of a first embodiment
of an outer mask 60. Outer mask 60 is formed of aluminum, steel, or
another material.
[0039] Outer mask 60 includes a hollow, vertically-extending body
61. Outer mask 60 is sized so that a disk 22 will fit horizontally
within the round central aperture 67 of body 61. A lip 62 is at an
upper first end of body 61 and extends inwardly around aperture 67.
Lip 62 extends over a circumferential portion of disk 22, and
thereby masks the outer periphery of disk 22 during the sputtering
process. Lip 62 does not contact the sputtered surface of the disk.
The upper surface of lip 62 (which is exposed to direct sputter
deposition) has numerous asperities 49 thereon to catch sputtered
material, although asperities 49 may be omitted. A horizontal
flange 63 extends outwardly from an outer surface of body 61. In
one embodiment, flange 63 may be present around the entire outer
surface 65 of body 61. In other embodiments, one or more (e.g.,
four) discrete flanges or other protrusions maybe spaced around the
outer surface 65 of body 61. The inner surface of body 61 includes
a tapered portion 66 adjacent to end 64, where disk 22 enters
aperture 67. The inner surface of body 61 also includes a groove
68, which is engaged by a helical spring 41 (FIG. 7) in the tray 39
upon which disk 22 rests during the sputtering process. The outer
mask gripper of the end effector grips mask 60 on the unsputtered
outer surface 65 of body 61 beneath flange 63, and may use the
lower surface of flange 63 to lift outer mask 60.
[0040] FIG. 6 is a cross-sectional side view of an alternative
outer mask 69. Most of the features of outer mask 69 are the same
as those of outer mask 60 of FIG. 5. Instead of having a flange 63,
however, outer mask 69 has a groove 70 in outer surface 65 that is
engaged by the outer mask gripper of the end effector.
[0041] FIG. 7 is a cross-sectional view of a first embodiment of an
end effector 28A (or 28B) of FIG. 1. In this view, end effector 28A
is positioned at loadlock 24 (FIG. 1) so that lid 32 is covering
loadlock opening 24A. End effector 28A includes an inner mask
gripper 29 and an outer mask gripper 30, the component parts of
which are described below. Inner mask gripper 29 is gripping inner
mask 42, and outer mask gripper 30 is gripping outer mask 60.
[0042] Disk 22 of FIG. 7 is captured and centered on inner mask 42,
and is horizontally disposed within outer mask 60. Disk 22 rests
horizontally on a metal tray 39, which in turn rests on a
vertically moveable pedestal 27 (FIG. 1). In particular, disk 22 is
supported on flat-topped annular protrusions that extend from the
top surface of tray 39. The protrusions are located near the center
of disk 22 and at the periphery of disk 22, respectively.
[0043] Tray 39 also supports inner masks 42 and outer mask 60. Body
44 (FIG. 3) of inner mask 42 is supported in a central aperture in
tray 39. Spring 48 (FIG. 3) of inner mask 42 presses against the
sidewall of the central aperture in tray 39, and thus provides a
supportive engagement with tray 39. Second end 64 (FIG. 4) of outer
mask 60 is supported above an outwardly extending flange 40 of tray
39. A helical spring coil 41 in a groove around tray 39 engages
groove 58 (FIG. 5) on the inside surface of body 61 of outer mask
60 and applies an outward force, thereby supporting and securing
outer mask 60 to tray 39. The metal to metal contacts between inner
mask 42 and outer mask 60, on the one hand, and tray 39 on the
other allow heat from the plasma to be conducted from inner mask 42
and outer mask 60 to tray 39, which prevents heat damage to disk
22.
[0044] Pedestal 27 is vertically raised to bring a processed disk
22, tray 39, inner mask 42, and outer mask 60 from the carousel
carrier in the main vacuum chamber to loadlock 24. Pedestal 27 is
vertically lowered to bring an unprocessed disk 22, tray 39, inner
mask 42, and outer mask 60 to the carousel carrier from loadlock
24.
[0045] Inner mask gripper 29 includes gripper fingers 34 that are
inserted into aperture 45 of inner mask 42. Gripper fingers 34 are
connected to gripper arms 33. A linear actuator 31 and a bellows 3
1A cause gripper arms 33 and gripper fingers 34 to move laterally
back and forth, as shown by the two headed arrow of FIG. 7. When
gripper arms 33 are moved apart (the "open" position), gripper
fingers 34 push against inner wall 45A of aperture 45 of inner mask
42 with sufficient force to allow inner mask 42 and disk 22 to be
lifted and moved. When gripper fingers 34 are moved together (the
"closed" position), inner mask 42 is released onto tray 39. Gripper
fingers 34 may be threaded to enhance their grip on inner mask 42.
Inner mask 50 of FIG. 4 maybe used instead of inner mask 42.
[0046] A feature of inner mask gripper 29 is that inner masks 42
and 50 are only gripped on vertically-extending sidewall 45A within
aperture 45, which is not subjected to direct sputter deposition.
Artisans will appreciate that numerous methods may be implemented
for gripping the inner mask within central aperture 45.
[0047] Outer mask gripper 30 of FIG. 7 is shown in an enlarged view
in FIG. 8. Threads 35 mount outer mask gripper 30 to lid 32. Outer
mask gripper 30 includes a rotary actuator 37 that rotates an "L"
shaped cam 36 that grips outer mask 60 (FIG. 5). When actuator 37
rotates cam 36 into the "open" position, the horizontal portion of
cam 36 is positioned beneath flange 63 (FIG. 5) so that outer mask
60 may be lifted by cam 36. When actuator 37 rotates cam 36 into a
"closed" position, cam 36 is positioned so that there is no overlap
between cam 36 and flange 63, thereby releasing outer mask 60.
[0048] The number of outer mask grippers 30 of end effector 28A may
vary. For example, FIG. 9A is illustrates an end effector 28A
having four outer mask grippers 30 at 90 degree angles to each
other. In an alternative embodiment, two or three outer mask
grippers 30 may be used.
[0049] FIG. 9B illustrates another embodiment an outer mask gripper
30-1 for end effector 28A. In this embodiment, one rotational
actuator 37 is used to control three cams 36. The cams 36 are
connected by a timing belt 38 that provides for synchronized
motion. The rotation of actuator 37 to the "open" position moves
each of the cams 36 beneath flange 63 in a coordinated fashion.
Inner mask gripper 29 is within timing belt 38.
[0050] FIG. 10 is a simplified view alternative embodiment of end
effector 28A for use with outer mask 69 of FIG. 6. For simplicity,
inner mask gripper 29 is not shown. In this embodiment, each of
four outer mask grippers 80 includes a pneumatic actuator, air
passage 81 (shown in part), and bellows 82. When outer mask gripper
80 is in an "open" position, a plunger 83 is moved toward outer
mask 69. Plunger 83 moves toward outer mask 69 and engages groove
70 of outer mask 69 (FIG. 6), thereby gripping outer mask 69. When
the pneumatic pressure is released, springs 93 in hollow
cylindrical body 92 force plunger 83 outward, thereby moving
gripper 20 to the "closed" position and releasing outer mask
69.
[0051] In FIG. 10, end 64 of outer mask 69 is resting on a flange
85 of a metal substrate transport tray 84. Tray 84 supports disk
22, inner mask 50 and outer mask 69 on the carousel and in the
sputtering chambers, similar to tray 39 of FIG. 7. Tray 84 has a
central aperture in which inner mask 50 is inserted and supported.
Tray 84 is on a vertically moveable pedestal 27-1, which is similar
to pedestal 27 of FIG. 7.
[0052] FIG. 11 illustrates pertinent portions of an alternative
embodiment of an end effector 28A. In this embodiment, only a
single actuator and a single feed-through are used to grip both the
inner mask and the outer mask. In addition, lid 32-1 is flat,
rather than peaked like lid 32 of FIG. 7.
[0053] In FIG. 11, inner mask gripper 29 is the same as shown in
FIG. 7, except that inner mask gripper arm 33 includes a flange 86
that extends outwardly from each arm 33. A flexure 88 of steel,
spring steel, or the like is connected between flange 86 and a
metal (e.g., steel or aluminum) outer mask gripper 87. Outer mask
gripper 87 has roughly a "C" shape and is supported on pin 90. Pin
89 links movement from gripper arm 33 and slides and rotates pin
90. Flexure 88 is connected to pin 89.
[0054] When inner mask gripper 29 moves gripper arms 33 and gripper
fingers 34 to an "open" position so as to engage inner mask 42,
flexure 88 moves laterally outward, which causes outer mask gripper
87 to rotate towards outer surface 65 of outer mask 60 (FIG. 5). A
horizontal gripper finger 91 of outer mask gripper 87 is thereby
positioned closely beneath flange 63 of outer mask 60 (FIG. 5) so
that outer mask 60 may be lifted by finger 91 of outer mask gripper
87. When inner mask gripper 29 moves gripper arms 33 and gripper
fingers 34 to a closed position, flexure 88 moves laterally inward,
which causes outer mask gripper 87 to be rotated away from outer
mask 60 so that there is no longer any overlap between flange 63
and finger 91, and thereby releases outer mask 60.
[0055] Thus, in the embodiment of FIG. 11, the motion of inner mask
gripper 29 is used to cause a gripping of both inner mask 42 and
outer mask 60. Other ways of borrowing the motion of inner mask
gripper 29 to grip outer masks 60 or 69 (FIGS. 5 and 6) will be
readily apparent to practitioners of the mechanical arts. Such
methods include using cables and/or linkages. Conversely, the
motion of an outer mask gripper 30 of FIG. 7 could be borrowed to
grip inner masks 42 or 50 in alternative embodiments.
[0056] A feature of the outer mask grippers shown in FIGS. 7
through 11 is that outer masks 60 and 69 are only gripped on an
outer surface that is not subject to direct sputter deposition.
Artisans will appreciate that numerous methods may be implemented
for gripping the unsputtered portion of the outer mask other than
using the example methods shown herein.
[0057] The operation of the substrate handling system 21 of FIG. 1
will be described with the aid of FIGS. 12a-12f. FIG. 12a shows
substrate handling system 21 in a down position. End effector 28A
is located at an external disk change station 100. Inner mask 42
and outer mask 60 are gripped (i.e., "open" position) by the inner
mask gripper and outer mask gripper, respectively, of end effector
28A. A vacuum system or some other disk loading system at disk
change station 30 is used to place an unprocessed disk 22 onto
inner mask 42 and within outer mask 60. While inner mask 42 and
outer mask 60 are at disk changing station 30, and in route to and
from disk changing station 30, masks 42 and 60 are exposed to
ambient and therefore can cool.
[0058] Meanwhile, the opposing end effector 28B is located at
loadlock 24 of sputtering system 20. End effector 28B is not
engaged with a disk 22, inner mask 42, or outer mask 60, but the
carousel of sputtering system 20 has been indexed to position a
processed optical disk 22, inner mask 42, outer mask 60, and tray
39 beneath end effector 28B. As mentioned above, inner mask 42,
outer mask 60, and tray 39 accompany disk 22 on the carousel and to
the sputtering stations of sputtering system 20. The inner mask
gripper and outer mask grippers are in a "closed" position. Lid 32
of end effector 28B covers opening 24A of loadlock 24. FIG. 12b has
pedestal 27 of sputtering system 20 (FIG. 1) in up position.
Pedestal 27 moves a processed disk 22, masks 42 and 60, and tray 39
to meet loadlock 24 and end effector 28B. Tray 39 also seals the
lower access to loadlock 24 when pedestal 27 is in its up position,
which isolates loadlock 24 from the main vacuum chamber of
sputtering system 20. After pedestal 27 has risen, loadlock 24
vents to the atmosphere. After the venting is complete or during
venting, the inner mask gripper and outer mask gripper of end
effector 28B are moved to their respective open positions so that
processed inner mask 42 and outer mask 60 are gripped by end
effector 28B, thereby capturing disk 22A.
[0059] FIG. 12c shows substrate handling system 21 in an up
position, which raises end effectors 28A and 28B. End effector 28B
is gripping a processed disk 22, inner mask 42, and outer mask 60,
and end effector 28A is gripping an unprocessed disk 22, inner mask
42, and outer mask 60. Tray 39 stays in loadlock 24 and pedestal 27
stays up.
[0060] Next, as illustrated in FIG. 12d, substrate handling system
21 is rotated by 180 degrees, thereby locating end effector 28B at
disk change station 100, and end effector 28A at loadlock 24.
Pedestal 27 remains in an up position at loadlock 24.
[0061] FIG. 12e shows substrate handling system 21 having returned
to a down position. At disk change station 100, the unloading of
processed disk 22 from inner mask 42 of end effector 28B (and the
subsequent loading of another unprocessed disk 22 onto inner mask
42 and within outer mask 60 of end effector 28B) is accomplished by
the vacuum apparatus or other mounting system at disk change
station 100.
[0062] At loadlock 24 of FIG. 12e, lid 32 of end effector 28A is
placed over access opening 24A of loadlock 24 so as to form a
vacuum tight seal. End effector 28A pushes inner mask 42 and outer
mask 60 onto tray 39, securing masks 42 and 60 to tray 39. The
inner mask gripper and outer mask gripper are moved to the "closed"
position, thereby releasing the unprocessed disk 22, inner mask 42
and outer mask 60 onto tray 39. Next, loadlock 24 is pumped down to
create a vacuum.
[0063] FIG. 12f illustrates processed disk 22 after its separation
from end effector 28B at disk changing station 100. Disk changing
station 100 subsequently exchanges the processed disk with an
unprocessed disk 22. Meanwhile, at loadlock 24, pedestal 27 is
lowered through an aperture in the carousel so that unprocessed
disk 22, inner mask 42, outer mask 60, and tray 39 are placed on
the carousel system of sputtering system 20. Subsequently, the
carousel indexes while the plasma is off. The indexing of the
carousel locates another processed disk 22, inner mask 42, outer
mask 60, and tray 39 under end effector 28A. Whereupon, the cycle
described above is repeated, so that end effector 28A removes a
processed disk 22 from loadlock 24, and end effector 28B provides
an unprocessed disk 22 to loadlock 24. Substrate handling system 21
is capable of handling several thousand disks per day.
[0064] The material that is being sputtered onto disk 22 also coats
the upper surfaces of annular head 43 of inner mask 42 and lip 62
of outer mask 60 (FIGS. 3 and 5). Over time, the edges of annular
head 43 and circular lip 62 become irregular and extended further.
The combined effect of the deposition on the annular head 43 and
circular lip 62 is a reduction in coated surface area on the disk
and irregularity in the coated area boundaries. When this
deposition or other maintenance issues have made inner mask 42 and
outer mask 60 unusable, they are replaced by a new or refurbished
inner mask 42 and outer mask 60. Deteriorated inner mask 42 and
outer mask 60 are removed at disk change station 100 by closing the
inner mask gripper and outer mask gripper, thereby releasing inner
mask 42 and outer mask 60. A new inner mask 42 and outer mask 60
are provided for gripping by the end effector. There is no need for
a special mask change station, nor is there any need for venting
sputtering system 20 to change the masks.
[0065] The embodiments described above are exemplary only.
Variations will be apparent to artisans in view of the above
disclosure. The invention is limited only by the following
claims.
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