U.S. patent application number 11/399233 was filed with the patent office on 2007-10-11 for reactive sputtering chamber with gas distribution tubes.
This patent application is currently assigned to Applied Materials, Inc.. Invention is credited to Akihiro Hosokawa, John M. White, Yan Ye.
Application Number | 20070235320 11/399233 |
Document ID | / |
Family ID | 38573996 |
Filed Date | 2007-10-11 |
United States Patent
Application |
20070235320 |
Kind Code |
A1 |
White; John M. ; et
al. |
October 11, 2007 |
Reactive sputtering chamber with gas distribution tubes
Abstract
A sputtering apparatus for processing large area substrates is
provided. By introducing gas across the entire target surface, a
uniform composition film may be formed on the substrate. When the
gas is introduced merely at the perimeter, the gas distribution is
not uniform. By providing a gas introduction tube across the
processing area, the reactive gas will uniformly distribute to the
whole target. Also, providing the gas tube with multiple inner
tubes provides a quick, effective gas dispersion capability.
Inventors: |
White; John M.; (Hayward,
CA) ; Ye; Yan; (Saratoga, CA) ; Hosokawa;
Akihiro; (Cupertino, CA) |
Correspondence
Address: |
PATTERSON & SHERIDAN, LLP
3040 POST OAK BOULEVARD, SUITE 1500
HOUSTON
TX
77056
US
|
Assignee: |
Applied Materials, Inc.
|
Family ID: |
38573996 |
Appl. No.: |
11/399233 |
Filed: |
April 6, 2006 |
Current U.S.
Class: |
204/192.1 ;
204/298.02 |
Current CPC
Class: |
H01J 37/34 20130101;
H01J 37/32449 20130101; C23C 14/0063 20130101; H01J 37/3244
20130101 |
Class at
Publication: |
204/192.1 ;
204/298.02 |
International
Class: |
C23C 14/32 20060101
C23C014/32; C23C 14/00 20060101 C23C014/00 |
Claims
1. A sputtering apparatus for processing a substrate, comprising: a
vacuum chamber; a sputtering target mounted in the vacuum chamber;
a pedestal positioned in the vacuum chamber to support the
substrate; and a plurality of gas introduction tubes extending
across said vacuum chamber in an area between said target and said
pedestal wherein no collimator is present between said target and
said pedestal.
2. The sputtering apparatus as claimed in claim 1, wherein each
said tube comprises: at least one inner tube comprising a plurality
of openings; and an outer tube comprising a plurality of openings,
said outer tube surrounding said at least one inner tube; wherein
said openings of said outer tube do not line up with said openings
of said at least one inner tube.
3. The sputtering apparatus as claimed in claim 1, wherein each
said tube is grounded.
4. The sputtering apparatus as claimed in claim 1, wherein each
said tube is biased.
5. The sputtering apparatus as claimed in claim 1, wherein each
said tube is spaced greater than about 30 mm from said pedestal and
greater than about 30 mm from said target.
6. A sputtering apparatus for processing a substrate, comprising: a
vacuum chamber; a sputtering target; a pedestal positioned in the
vacuum chamber to support the substrate; and one or more gas
introduction tubes extending across said vacuum chamber in an area
between said target and said pedestal, each said tube comprising:
at least one inner tube comprising a plurality of openings; and an
outer tube comprising a plurality of openings, said outer tube
surrounding said at least one inner tube.
7. The sputtering apparatus as claimed in claim 6, wherein each
said gas introduction tube is grounded.
8. The sputtering apparatus as claimed in claim 6, wherein each
said gas introduction tube is biased.
9. The sputtering apparatus as claimed in claim 6, wherein each
said gas introduction tube is spaced greater than about 30 mm from
said pedestal and greater than about 30 mm from said target.
10. The sputtering apparatus as claimed in claim 6, wherein said
openings of said outer tube do not line up with said openings of
said at least one inner tube.
11. A method of sputtering a sputtering target in a sputtering
apparatus that comprises a vacuum chamber, a sputtering target, and
a plurality of gas introduction tubes extending across said vacuum
chamber in an area between said target and said substrate wherein
no collimator is present between said target and said substrate,
said method comprising: sputtering said target to deposit a layer
on a substrate while providing gas from said tubes.
12. The method as claimed in claim 11, wherein each said tube
comprises: at least one inner tube comprising a plurality of
openings; and an outer tube comprising a plurality of openings,
said outer tube surrounding said at least one inner tube; wherein
said openings of said outer tube do not line up with said openings
of said at least one inner tube.
13. The method as claimed in claim 11, wherein each said tube is
grounded.
14. The method as claimed in claim 11, wherein each said tube is
biased.
15. The method as claimed in claim 11, wherein each said tube is
spaced greater than about 30 mm from said substrate and greater
than about 30 mm from said target.
16. A method of sputtering a sputtering target in a sputtering
apparatus that comprises a vacuum chamber, a sputtering target, and
one or more gas introduction tubes extending across said vacuum
chamber in an area between said target and said substrate, each
said tube comprises at least one inner tube comprising a plurality
of openings and an outer tube comprising a plurality of openings,
said outer tube surrounding said at least one inner tube, said
method comprising: sputtering said target to deposit a layer on a
substrate while providing gas from said one or more gas
introduction tubes.
17. The method as claimed in claim 16, wherein each said gas
introduction tube is grounded.
18. The method as claimed in claim 16, wherein each said gas
introduction tube is biased.
19. The method as claimed in claim 16, wherein each said gas
introduction tube is spaced greater than about 30 mm from said
substrate and greater than about 30 mm from said target.
20. The method as claimed in claim 16, wherein said openings of
said outer tube do not line up with said openings of said at least
one inner tube.
21. A gas introduction tube comprising: at least one inner tube
comprising a plurality of openings; and an outer tube comprising a
plurality of openings, said outer tube surrounding said at least
one inner tube.
22. The gas introduction tube as claimed in claim 21, wherein said
openings of said outer tube do not line up with said openings of
said at least one inner tube.
23. The gas introduction tube as claimed in claim 21, wherein said
tube is grounded.
24. The gas introduction tube as claimed in claim 21, wherein said
tube is biased.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] Embodiments of the present invention generally relate to a
sputtering apparatus for forming films on large area substrate such
as flat panel, large screen televisions, and solar panels.
[0003] 2. Description of the Related Art
[0004] As demand for larger flat panel display screens increases,
so must the sputtering target area. As the sputtering target become
larger, it becomes increasingly more difficult to adequately
provide a uniform distribution of reactive gas to the sputtering
target. In the past, reactive gas has been introduced to the
sputtering chamber through a gas inlet. The gas inlet is typically
located on the side of the chamber. With an increase in target
size, the reactive gas tends to not adequately reach the center of
the target. When the reactive gas does not uniformly reach the
entire target, the film deposited on the substrate will not have a
uniform composition across the substrate. For a large area
sputtering targets with the gas introduced from the periphery of
the target, the gas concentration is highest at the chamber wall
where the gas inlet is located. The gas concentration decreases
moving across the chamber to a low point in the center of the
chamber.
[0005] U.S. Pat. No. 5,346,601 to Barada et al. shows a sputtering
apparatus in which two gas introduction tubes are provided within a
collimator. The gas introduction tubes are perpendicular to each
other and within the same plane. The gas tubes extend across the
processing area. By providing the gas introduction tubes within the
collimator, the reactive gas can adequately be provided to the
substrate while not shadowing the wafer from sputtering material. A
plurality of gas outlets are present across the tube. In order to
remove the gas tubes, the entire collimator structure must be
removed. The collimator cannot be removed without also removing the
gas tubes.
[0006] As shown by Barada et al., sometimes gas introduction tubes
can extend across the processing space between the target and the
substrate. The gas introduction tubes, such as that used by Barada
et al., usually only introduce gas through a series of gas outlet
holes formed in a gas introduction tube. A problem with prior art
gas introduction tubes is that they must provide the gas at a high
pressure through the tube in order to have a uniform pressure
passing through the tiny holes in the tube. When the process is
stopped and the gas is stopped, gas will continue to flow out of
the holes because of the pressure buildup within the tube. The gas
will continue to disperse into the processing chamber even after
the process has stopped. The excess gas introduced into the chamber
may contaminate the wafer or cause further, undesirable reactions
with the substrate.
[0007] There is a need in the art to provide reactive sputtering
gas to a chamber uniformly across a large area sputtering target.
There is also a need in the art to provide easily removable
reactive gas introduction tubes without disassembling the
sputtering chamber.
SUMMARY OF THE INVENTION
[0008] The present invention generally involves a sputtering
apparatus for forming films on large area substrates such as flat
panel, large screen televisions.
[0009] In a first embodiment, a sputtering apparatus has a vacuum
chamber, a sputtering target, a substrate support, and a plurality
of parallel gas introduction tubes. The gas introduction tubes
extend across the vacuum chamber in an area between the target and
the substrate support.
[0010] In a second embodiment, a sputtering apparatus has a vacuum
chamber, a sputtering target, a substrate support, and one or more
gas introduction tubes extending across the vacuum chamber in an
area between the target and the substrate support. Each tube has at
least one inner tube having a plurality of openings and an outer
tube having a plurality of openings. The outer tube surrounds the
at least one inner tube.
[0011] In a third embodiment, a method of sputtering a sputtering
target in a sputtering apparatus comprises sputtering the target to
deposit a layer on a substrate. The apparatus comprises a vacuum
chamber, a sputtering target, and a plurality of gas introduction
tubes extending across the vacuum chamber in an area between the
target and the substrate wherein no collimator is present between
the target and the substrate.
[0012] In a fourth embodiment, a method of sputtering a sputtering
target in a sputtering apparatus is provided that comprises
sputtering the target to deposit a layer on the substrate. The
sputtering apparatus comprises a vacuum chamber, a sputtering
target, and one or more gas introduction tubes extending across the
vacuum chamber in an area between the target and the substrate.
Each tube comprises at least one inner tube comprising a plurality
of openings and an outer tube comprising a plurality of openings.
The outer tube surrounds the at least one inner tube.
[0013] In a fifth embodiment, a gas introduction tube is disclosed
that comprises at least one inner tube comprising a plurality of
openings and an outer tube comprising a plurality of openings. The
outer tube surrounds the at least one inner tube.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] So that the manner in which the above recited features of
the present invention can be understood in detail, a more
particular description of the invention, briefly summarized above,
may be had by reference to embodiments, some of which are
illustrated in the appended drawings. It is to be noted, however,
that the appended drawings illustrate only typical embodiments of
this invention and are therefore not to be considered limiting of
its scope, for the invention may admit to other equally effective
embodiments.
[0015] FIG. 1 is a side view of a gas introduction tube used in the
instant invention.
[0016] FIG. 2 is a sputtering apparatus according to the instant
invention showing the spacing between the target, substrate, and
gas introduction tubes.
[0017] FIGS. 3A-3D are cross sectional representations of gas
introductions tubes.
[0018] FIG. 4 is an isometric view of a lower chamber assembly in
an exemplary physical vapor deposition chamber.
[0019] FIG. 5 is an isometric cross-sectional view of gas
introduction tubes formed in an exemplary physical vapor deposition
chamber.
[0020] FIG. 6 is an isometric cross-sectional view of a lower
chamber assembly in an exemplary physical vapor deposition chamber
according to this invention.
[0021] FIG. 7 is an isometric cross-sectional view of gas
introduction tubes formed in an exemplary physical vapor deposition
chamber according to this invention.
DETAILED DESCRIPTION
[0022] The present invention generally provides an apparatus to
introduce reactive gas to a sputtering target apparatus. The
sputtering apparatus can be small enough to process semiconductor
wafers or sufficiently large to process large area substrates used
in making flat panel television screens.
[0023] FIG. 2 is an exemplary schematic of a sputtering apparatus
incorporating the instant invention. An exemplary sputtering
apparatus which can be modified to incorporate the instant
invention is shown in U.S. patent application Ser. No. 11/247,705
filed Oct. 11, 2005 and hereby incorporated by reference in its
entirety. The target 9 rests on a backing plate 8 within a vacuum
chamber 7. The substrate 12 is positioned in opposition to the
target 9. The substrate 12 rests on a pedestal 13. Between the
target 9 and the pedestal 13, gas introductions tubes 14 are found.
These tubes 14 extend across the chamber. As few as one and as many
as necessary can be provided. If more than one tube 14 is provided,
the tubes 14 are substantially parallel to each other and in the
same plane as each other. In one embodiment, the gas introduction
tubes 14 are spaced about 100 mm to about 300 mm apart. In another
embodiment, the gas introduction tubes 14 are spaced about 150 mm
to about 180 mm apart as shown by arrow E. The tubes 14 are located
about halfway between the target 9 and the substrate 12, but the
tubes 14 should be greater than about 30 mm away from the substrate
12 and greater than about 30 mm away from the target 9. If the gas
tubes 14 are closer than 30 mm to the target 9, the tubes 14 will
likely disturb the plasma by sinking an excessive fraction of
electrons from it and form a layer on the target 9. If the gas
tubes 14 are closer than 30 mm to the substrate 12, then the gas
tubes 14 will block material from evenly reaching the substrate 12
so that a non-uniform film will be formed. The target 9 and
substrate 12 can be separated by about 300 mm to about 360 mm. The
target 9 would then be about 150 mm to about 180 mm from the tubes
14 as shown by arrow C. The substrate 12 would then be about 150 mm
to about 180 mm from the tubes 14 as shown by arrow D.
[0024] The gas tubes 14, while located between the target 9 and the
substrate 12, are not intended to provide any collimating effect.
In fact, it is preferable that the gas tubes 14 do not provide any
collimating effect. No collimator should be present. A collimator
will interfere with the uniform distribution of material on the
substrate 12. Therefore, only as many gas tubes 14 as are necessary
to ensure a uniform gas distribution should be present within the
chamber. One or more gas tubes 14 could be present. The gas tubes
14 can run in a substantially 2-dimensional plane and could be
parallel or substantially parallel. Alternatively, the gas tubes 14
can intersect or even overlap.
[0025] By extending the gas introduction tubes 14 across the
processing area, the reactive gas can be evenly provided to the
target 9 for reaction. When the gas is provided at the periphery,
the gas is not evenly distributed to the target 9. When the gas is
not evenly distributed, the resulting film will not be uniform in
composition across the surface. By providing the reactive gas along
the length of the target 9, the reactive gas will be uniformly
provided to the target 9 and the deposited film will have a uniform
composition across its surface. It is especially difficult to
provide reactive gas uniformly to the target 9 when the target 9 is
a large area target 9 used for forming flat panel television
screens.
[0026] As noted above, the prior art gas introduction tubes will
still emit gas into the processing region even after the gas has
been turned off and the process stopped. The gas continues to flow
into the processing region because of the high pressure buildup
within the gas introduction tube and the tiny holes through which
the gas will pass. Simply increasing the hole size would certainly
decrease the pressure and allow the reactive gas to stop flowing
upon shutdown, but more gas will leave the tube at the hole closest
to the edge than will leave at each additional hole along the gas
tube. The larger holes will decrease the pressure and, thus, allow
less gas to be introduced at the center of the target 9.
[0027] Because increasing the hole size will not solve the gas
introduction problem, another solution was found to maintain
sufficient pressure within the tube to uniformly provide gas to the
whole target surface and to also quickly reduce pressure within the
tube at shutdown. FIG. 1 shows an exemplary gas introduction tube
according to the instant invention. The gas introduction tube 3
contains numerous other tubes within the tube. For clarity, only
three tubes are shown in the figure, but it is understood that as
many tubes as are practically necessary could be provided. The
outer tube has a wall 4 with numerous holes along its length.
Within the outer tube is a middle tube that has a wall 5. The
middle tube has numerous holes along its length as well. Within the
middle tube is an inner tube that has a wall 6 with numerous holes
along its length.
[0028] The gas introduction tube 3 provides a uniform gas pressure
along the length of the tube and quick dispersion of gas at
shutdown. Gas flows into the tube 3 through the inner tube at a
high pressure. The gas passes through the tube 3 and passes through
the wall 6 to the middle tube. The gas in the middle tube is then
dispersed through the wall 5 to the outer tube. The gas in the
outer tube is then dispersed through wall 4 to the processing
chamber. The holes in the walls of the tubes are not lined up. If
the holes are lined up, then the gas would disperse directly from
the inner tube to the chamber. Such a situation would render the
tube 3 exactly the same as the tube of the prior art in
effectiveness. By misaligning the holes, the gas must snake through
the processing tubes and decrease in pressure as it passes through
the holes. By providing the gas in the inner tube at a high
pressure, the gas will snake through the middle tube and outer tube
until it reaches the processing chamber. Each time the gas passes
through a hole to another tube, the pressure will drop. When the
gas is turned off, the pressure will rapidly drop within the tube
and prevent unwanted gas introduction.
[0029] FIGS. 3A-3D show cross sections of gas tubes 3A-3D. The gas
tubes 3A-3D can be round (FIG. 3A), oval (FIG. 3B), square (FIG.
3C) or any conventional shape. So long as the shape of the tubes
does not interfere with sputtering target material, the shape of
the gas introduction tubes is not restricted. FIG. 3D shows a
circular gas instruction tube 3D that has a plurality of holes F.
The holes F are the outlets for the gas to pass into the chamber.
The holes F can face downward towards the substrate, upwards toward
the target, or sideways away from both the target and the
substrate. In one embodiment, the holes F face away from the target
and the substrate. The holes F should be present on less than about
10% of the gas introduction tube 3D. In one embodiment, about 10 to
about 50 holes F can span the length of the tube. In another
embodiment, about 25 to about 35 holes F can span the length of the
tube. The size of the holes F should be much smaller than the
diameter of the tubes. In one embodiment, the holes F are about 5
times smaller than the diameter of the tube. In another embodiment,
the holes F are about 10 times smaller than the diameter of the
tube. The diameter of the tubes can be about 1/8'' to about 7/8''.
In another embodiment, the diameter of the tubes can be about 1/4''
to about 3/4''.
[0030] The gas introduction tubes 14 can have a bias applied to
them. The bias can be applied to an individual tube 14 or
collectively to all tubes 14. The tubes 14 can have an RF bias
applied so that the gas introduction tubes 14 will function not
only as a gas source, but also as an ionization source. The gas
tubes 14 could also have an AC, DC, or pulsed bias applied from a
power source 2 or the tubes 14 can be grounded (see FIG. 2). The
gas introduction tubes could be used as an additional sputtering
target if desired. The gas tubes should be made of the same
material as the sputtering target to prevent contamination.
[0031] The gas introduction tubes 14 can also be tailored to suit
the needs of the user. For example, multiple tubes 14 can be used
with each tube 14 providing a different processing gas.
Additionally, the instant invention provides the added benefit of
functionality. The tubes 14 can be easily removed through the
access port. By removing the tubes 14 through the access ports, the
entire chamber does not need to be disassembled to simply change a
few tubes 14. Benefits of such an easy removal are clear. Downtime
is significantly reduced.
[0032] In one embodiment of the process chamber 10, illustrated in
FIG. 4, the lower chamber assembly 35 may contain one or more gas
introduction tubes 14. In one embodiment, each tube 14 extends
through the processing region 15. In this configuration the tubes
14 are in electrical contact with the grounded shield 50, so that
current flowing through the tubes 14 passes through the shield 50
to ground. In another configuration, the tubes 14 are biased and
not in contact with the shield 50. In one embodiment, the tubes 14
are positioned over the stationary conductive member support 97 and
is used to hide or isolate the conductive member support 97 from
the plasma generated in the processing region 15 (FIG. 6). The
ability to hide or isolate the conductive member 97 from the plasma
will reduce the amount of deposition that will land on the
stationary conductive member support 97 and thus minimize particle
generation as the tubes 14 are removed from processing region 15 of
the process chamber 10. In one embodiment, the tubes 14 are longer
than the target surface in the dimension in the direction in which
the tubes 14 extend and thus the conductive member support(s) 97
are not positioned below the target surface so as to limit the
interaction between the plasma generated in the processing region
15 and the conductive member support(s) 97.
[0033] In FIG. 4 the lid assembly has been removed, and is not
shown, to more clearly illustrate some of the components in the
lower processing chamber assembly 35. In the embodiment shown in
FIG. 4, the lower chamber assembly 35 generally contains a
substrate support assembly 60, chamber body assembly 40, a gas
delivery system 14 and a shadow frame 52. In one aspect, as shown
in FIG. 4 the chamber body assembly 40 generally contains a process
kit holder 140, one or more chamber walls 41 and a chamber base 42.
The process kit holder 140 is positioned on the chamber walls 41
and is adapted to support the shield 50, an upper shield 50E and
one or more tubes 14 (e.g., three shown in FIG. 4). In one aspect,
the process kit holder 140 electrically connects the shield 50 and
the upper shield 50E to the chamber walls 41 which are grounded.
The shield 50 and upper shield 50E are generally sized and adapted
to prevent the plasma and sputtered target material from escaping
from the process region 15 and depositing on the components in the
lower chamber assembly 35. In the configuration illustrated in FIG.
4 the lower chamber assembly 35 contains three tubes 14 that are
positioned above the substrate support 61. In one aspect, as shown
in FIG. 4, the conductive member support 97 is mounted on and
electrically connected to the grounded shield 50.
[0034] It should be noted that the cross-sectional area and the
material used to form the components in the tube 14, the conductive
member 93, and the conductive member support 97 is important since
it will affect the ability to withstand the high temperatures that
it will be seen during processing (e.g., resistive heating and
interaction with the plasma). The number of tubes 14 and the
surface area of the conductive member 93 exposed in the processing
region 15 is important since it will have an effect amount of
current carried by each conductive member 93 and thus the maximum
temperature achieved by each conductive member 93 and conductive
member support 97 during processing. The total surface area of the
conductive member 93 can be defined by the length of the conductive
member 93 in the processing region times the length of the exposed
perimeter of the conductive member 93 times the number of
conductive members positioned in the processing region. In one
aspect, the number of gas tubes 14 positioned in the processing
region 15 may be between about one and about twenty depending on
the desired process uniformity, cost and complexity allowed for a
desired application. Preferably, the number of gas tubes 14 that
pass through the processing region 15 is as few as possible with a
preferred range of between about two and about ten. The exposed
perimeter of the embodiment of the conductive member 93 illustrated
in FIG. 7 can generally be defined as twice the vertical length
plus the horizontal length of surface of the conductive member 93.
In one example, for a substrate that is 1800 mm.times.1500 mm in
size the exposed surface area of all of the conductive members 93
was about 5.0 m.sup.2, which is spread across seven conductive
members 93 that were 1.9 meters long. In one aspect, the
cross-sectional area of the conductive member 93 is sized to carry
the current delivered to the conductive members 93 from the plasma
generated by the target bias. In one example, the total current
that could be carried by all of the conductive members is about
1000 amps.
[0035] While FIGS. 4-7 illustrate embodiments of the tubes 14 that
are generally straight and are generally rod or bar shaped, this
configuration is not intended to limit the scope of the invention
described herein. In general, the term bar, or rod, shaped as used
herein is intended to described a component that is longer (e.g.,
X-direction) than its cross-section is wide or high. In one aspect,
the bar or rod shaped tubes 14 are not straight and thus have one
or more regions along their length that are curved or coiled. In
one embodiment, the tubes 14 are positioned throughout the
processing region to improve the sputter deposited film uniformity
on the substrate surface by increasing the tube surface area and
not appreciably obstructing or altering the amount and/or direction
of the flux of sputtered material passing from the target to the
substrate surface. Referring to FIGS. 3A-3D, in one embodiment, the
cross-section of the tubes 14 are oval, round, rectangular, or
other cross-sectional shape that will not appreciably obstruct or
alter the amount and/or direction of the flux of sputtered material
passing from the target to the substrate surface.
[0036] FIG. 5 illustrates an exploded isometric view of a tube 14
that has a conductive member electrical connection point 105 that
is adapted to electrically contact a support electrical connection
point 104 of the support 102. In one aspect, the conductive member
electrical connection point 105 and the support electrical
connection point 104 act as a pivot point 106 that allows the tube
14 to be positioned in and/or removed from the processing region 15
(discussed below). To hide the pivot point 106 a support cover 103
is positioned over this region to prevent the sputtered material
deposition from inhibiting the removal of these components from the
process region 15. The conductive member support 97 may have a
pivot point 106 at one end and an end that is detachable from the
other vertical support.
[0037] In one embodiment, not shown, the tubes 14 are cantilevered
over the substrate surface and thus do not extend all the way
across the substrate. In one aspect, the cantilevered end of the
tubes 14 may only extend to a point that is above the center of the
substrate positioned on the substrate support. In one aspect, the
cantilevered tubes 14 are evenly distributed throughout the
processing region 15.
[0038] While the embodiments of the process chamber 10 illustrated
herein all show the tubes 14 in contact with the shield 50, this
configuration is not intended to be limiting to the scope of the
invention described herein. Therefore, in some embodiments the
vertical support may be mounted on a bracket or supporting surface
positioned in the chamber body assembly 40.
Gas Tube Removal
[0039] FIG. 6 is an isometric cross-sectional exploded view as
viewed from outside the process chamber 10 that illustrates the
tubes 14 and plates 99 in a position that is partially removed from
the processing region 15 of the process chamber 10. In one
embodiment of the invention, the tubes 14 are adapted to be removed
from the process chamber 10 through an access port 98 formed in the
process kit holder 140. In one aspect, the access port 98 may be
formed in the chamber wall 41. In FIG. 6, the lid assembly has been
removed to more clearly illustrate some of the components in the
lower processing chamber assembly 35. The tube 14 has a handle 93A
that is attached or welded to the surface of the gas introduction
tubes 14 to facilitate the insertion and/or removal of the gas
introduction tubes 14 through the access port 98 formed in the
process kit holder 140.
[0040] When the tube 14 has reached its useable lifetime, the tube
14 can be removed from the processing region 15 by venting the
process chamber 10 and removing a plate 99 that is sealably
attached to the process kit holder 140 so that a user can access
the tube 14 through the access port 98. The process of removing the
tube 14 may include shutting "off" the vacuum pumps (not shown) and
then delivering a flow of an inert gas, such as argon, into the
vacuum processing area from the tubes 14 to create a pressure
greater than atmospheric pressure in the vacuum processing area.
Creating a positive pressure in the processing area during the
removal of the tube 14 may be advantageous since it can prevent the
contamination of the chamber components positioned in the
processing region 15 due to the exposure of the process kit
components to atmospheric contamination (e.g., atmospheric gases,
vapors or particles). In one aspect, the access ports 98 are
purposely kept as small as possible to minimize the area through
which atmospheric contamination can enter the processing region 15.
The down time of the processing chamber 10 can thus be minimized
since there is no need to remove and reposition the chamber lid
assembly 20 and/or other major chamber components, there is no need
to bake out of the chamber to remove adsorbed gases and water from
processing chamber components, and there is no need to replace
contaminated components due to their exposure to atmospheric
contamination.
Gas Introduction Tube Bias
[0041] In one embodiment of the process chamber 10, a biasable
shield 50F may be positioned in the processing region to change the
electric field and the plasma density generated near the edge of
the target and substrate. FIG. 7 illustrates one embodiment of the
biasable shield 50F that is positioned around the periphery of the
substrate 12 and is electrically connected to the shield 50, which
is grounded, by use of an electrical component 50G. In one aspect,
the electrical component 50G may be used as a "stand-off" to
physically space the biasable shield 50F from the shield 50. It
should be noted that the term "grounded" is generally intended to
describe a direct or in-direct electrical connection between a
component and the anode. The biasable shield 50F may be purposely
biased at a different potential versus the tube surfaces due to the
introduction of the electrical component 50G that may add
resistive, capacitive and/or inductive type elements to the
electrical path between the biasable shield 50F and the tube
surfaces. In one aspect, during processing a bias voltage, which
will generally be less anodic, may be "passively" induced in the
biasable shield 50F due to a bias applied between the target and
anodic surface (e.g., shield 50) and the interaction of the
biasable shield 50F with the plasma generated in the processing
region. In another aspect, not shown, the biasable shield 50F may
be separately biased by use of a power supply (not shown) which is
in electrical communication with the biasable shield 50F and the
anode surfaces. In this configuration the electrical component 50G
may act as an insulator.
[0042] In another embodiment of the processing chamber 10, the
tubes 14 may be purposely biased at a different potential versus
the anode surfaces by the introduction of a resistive, capacitive
and/or inductive components to the electrical path between the
tubes 14 and the anode surfaces. In one embodiment, as shown in
FIG. 7, a second electrical component 50H may be positioned in the
electrical path between the tube 14 and the shield 50 to allow the
tube 14 to be biased at a different potential than the shield 50.
In one aspect, during processing a bias voltage, which will
generally be less anodic, may be "passively" induced in the tube 14
due to a bias applied between the target and anodic surface (e.g.,
shield 50) and the interaction of the tube 14 with the plasma
generated in the processing region. In another aspect, the tube 14
may be separately biased by use of a power supply (see FIG. 2)
which is in electrical communication with the tubes 14. In this
configuration the second electrical component 50H may act as an
insulator.
[0043] While the foregoing is directed to embodiments of the
present invention, other and further embodiments of the invention
may be devised without departing from the basic scope thereof, and
the scope thereof is determined by the claims that follow.
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