U.S. patent number RE47,440 [Application Number 15/678,883] was granted by the patent office on 2019-06-18 for apparatus and method for providing uniform flow of gas.
This patent grant is currently assigned to Applied Materials, Inc.. The grantee listed for this patent is Applied Materials, Inc.. Invention is credited to Mei Chang, David Chu, Faruk Gungor, Chien-Teh Kao, Hyman Lam, Paul F. Ma, Dien-Yeh Wu, Joseph Yudovsky.
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United States Patent |
RE47,440 |
Yudovsky , et al. |
June 18, 2019 |
Apparatus and method for providing uniform flow of gas
Abstract
Provided are gas distribution apparatus with a delivery channel
having an inlet end, an outlet end and a plurality of apertures
spaced along the length. The inlet end is connectable to an inlet
gas source and the outlet end is connectable with a vacuum source.
Also provided are gas distribution apparatus with spiral delivery
channels, intertwined spiral delivery channels, splitting delivery
channels, merging delivery channels and shaped delivery channels in
which an inlet end and outlet end are configured for rapid exchange
of gas within the delivery channels.
Inventors: |
Yudovsky; Joseph (Campbell,
CA), Chang; Mei (Saratoga, CA), Gungor; Faruk (San
Jose, CA), Ma; Paul F. (Santa Clara, CA), Chu; David
(Campbell, CA), Kao; Chien-Teh (Sunnyvale, CA), Lam;
Hyman (San Jose, CA), Wu; Dien-Yeh (San Jose, CA) |
Applicant: |
Name |
City |
State |
Country |
Type |
Applied Materials, Inc. |
Santa Clara |
CA |
US |
|
|
Assignee: |
Applied Materials, Inc. (Santa
Clara, CA)
|
Family
ID: |
48134979 |
Appl.
No.: |
15/678,883 |
Filed: |
August 16, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
61548942 |
Oct 19, 2011 |
|
|
|
Reissue of: |
13653952 |
Oct 17, 2012 |
9109754 |
Aug 18, 2015 |
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C23C
16/45565 (20130101); C23C 16/4412 (20130101); F17D
3/00 (20130101); C23C 16/45536 (20130101); F17D
3/00 (20130101); C23C 16/45578 (20130101); C23C
16/45544 (20130101); Y10T 137/7833 (20150401); Y10T
137/7833 (20150401) |
Current International
Class: |
F17D
3/00 (20060101); F16K 11/20 (20060101) |
Field of
Search: |
;137/561R,561A,597
;156/345.33,345.34 ;239/558 ;427/479 |
References Cited
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Other References
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|
Primary Examiner: Doerrler; William C
Attorney, Agent or Firm: Patterson + Sheridan, LLP
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority under 35 U.S.C. .sctn. 119(e) to
U.S. Provisional Application No. 61/548,942, filed Oct. 19, 2011.
Claims
What is claimed is:
1. A gas distribution apparatus for controlling flow of gas into a
process chamber, comprising: a spiral delivery channel having an
inlet end, an outlet end and a length, the delivery channel having
a plurality of apertures spaced along the length; an inlet on the
inlet end of the delivery channel, the inlet connectable to a gas
source, wherein flow of the gas is controllable by a gas valve in
communication with the inlet; and an outlet on the outlet end of
the delivery channel, the outlet connectable to a vacuum source,
wherein vacuum pressure through the outlet is controllable by an
outlet valve to provide a reduced pressure at the outlet; and a
controller to regulate the flow of the gas through the delivery
channel and into the process chamber by opening and closing the
outlet valve during gas delivery and gas purging in the channel to
control the flow of gas through the apertures along the length of
the channel.
2. The gas distribution apparatus of claim 1, wherein a flow of gas
through the gas distribution apparatus has a more uniform
conductance along an axial length of the gas distribution apparatus
than the flow of gas through a similar gas distribution apparatus
without the vacuum source connected to the outlet.
3. The gas distribution apparatus of claim 1, wherein when the gas
valve is closed, the gas is purged from the delivery channel faster
than a similar gas distribution apparatus without the vacuum
source.
4. The gas distribution apparatus of claim 1, wherein the delivery
channel is a recessed channel in a back side of a gas distribution
plate and the plurality of apertures extend through the gas
distribution plate to a front side of the gas distribution
plate.
5. The gas distribution apparatus of claim 4, wherein the gas
distribution plate is round and the delivery channel forms a spiral
shape with one of the inlet end and outlet end positioned in an
outer peripheral region of the gas distribution plate and the other
of the inlet end and outlet end positioned in a central region of
the gas distribution plate.
6. The gas distribution apparatus of claim .[.3.].
.Iadd.4.Iaddend., wherein the inlet end is positioned at an outer
peripheral region of the gas distribution plate and the outlet end
is positioned at a central region of the gas distribution
plate.
7. The gas distribution apparatus of claim .[.3.].
.Iadd.4.Iaddend., wherein the outlet end is positioned at an outer
peripheral region of the gas distribution plate and the inlet end
is positioned at a central region of the gas distribution
plate.
8. The gas distribution apparatus of claim 4, wherein there are two
delivery channels recessed in the back side of the gas distribution
plate.
9. The gas distribution apparatus of claim 8, wherein each of the
delivery channels forms a spiral shape with one of the inlet end
and outlet end positioned in an outer peripheral region of the gas
distribution plate and the other of the inlet end and outlet end
positioned in a central region of the gas distribution plate.
10. The gas distribution apparatus of claim 9, wherein the two
delivery channels are intertwined along the spiral shape.
11. The gas distribution apparatus of claim 9, wherein each
delivery channel has the inlet end positioned in the outer
periphery region of the gas distribution plate and the outlet end
positioned in the central region of the gas distribution plate.
12. The gas distribution apparatus of claim 9, wherein each
delivery channel has the outlet end positioned in the outer
periphery region of the gas distribution plate and the inlet end
positioned in the central region of the gas distribution plate.
13. The gas distribution apparatus of claim 9, wherein inlet end of
one delivery channel is positioned in the outer periphery region of
the gas distribution plate and the outlet end of the other delivery
channel is positioned in the outer periphery region of the gas
distribution plate.
14. The gas distribution apparatus of claim 4, further comprising a
back cover on the back side of the gas distribution plate, the back
cover covering the recessed channel.
15. The gas distribution apparatus of claim 1, wherein the delivery
channel is a tubular spiral having a substantially planar
shape.
16. The gas distribution apparatus of claim 15, wherein the gas
distribution apparatus comprises a plurality of delivery
channels.
17. The gas distribution apparatus of claim 16, wherein more than
one of the delivery channels are connected to the inlet so that a
gas flowing through the inlet flows through each of the delivery
channels.
18. The gas distribution apparatus of claim 17, wherein each of the
delivery channels connected to the inlet merge and are connected to
one outlet.
19. The gas distribution apparatus of claim 17, wherein each of the
delivery channels connected to the inlet has a separate outlet
connected to a separate outlet valve.
20. The gas distribution apparatus of claim 19, wherein the
controller independently adjusts each of the outlet valves to
maintain a substantially uniform flow of gas through each of the
delivery channels.
21. The gas distribution apparatus of claim 16, wherein the
plurality of delivery channels are shaped so that .[.the.]. .Iadd.a
.Iaddend.hole pattern seen by a substrate is uniform across the gas
distribution apparatus.
22. A processing chamber comprising the gas distribution apparatus
of claim 1.
23. The processing chamber of claim 22, wherein the gas
distribution apparatus comprises a tubular spiral having a
substantially planar shape, the gas distribution apparatus
positioned between a substrate support and a gas distribution
plate.
24. A gas distribution apparatus, comprising: a spiral gas delivery
channel recessed in a back side of a gas distribution plate, the
recessed gas delivery channel having an inlet end, an outlet end
and a length, the gas delivery channel having a plurality of
apertures spaced along the length extending through the gas
distribution plate to a front side of the gas distribution plate so
that gas flowing through the gas delivery channel can pass through
the apertures exiting the gas distribution plate; a back cover on
the back side of the gas distribution plate, the back cover
covering the recessed channel; an inlet connected to the inlet end
of the gas delivery channel through the back cover, the inlet
connectable to a gas source, wherein a flow of gas is controllable
by a gas valve in communication with the inlet; an outlet connected
to the outlet end of the gas delivery channel through the back
cover, the outlet connectable to a vacuum source, wherein vacuum
pressure through the outlet is controllable by an outlet valve to
provide a reduced pressure at the outlet; and a controller to
regulate the flow of the gas through the gas delivery channel and
into a process chamber by opening and closing the outlet valve
during gas delivery and gas purging to control the flow of gas
through the apertures along the length of the channel.
25. The gas distribution apparatus of claim 24, wherein the gas
distribution plate is round and the delivery channel forms a spiral
shape with one of the inlet end and outlet end positioned in an
outer peripheral region of the gas distribution plate and the other
of the inlet end and outlet end positioned in a central region of
the gas distribution plate.
26. The gas distribution apparatus of claim 25, wherein there are
two delivery channels recessed in the back side of the gas
distribution plate, the two delivery channels intertwined along the
spiral shape.
.Iadd.27. A gas distribution apparatus, comprising: a plate having
a front surface and a back surface; a first recessed channel formed
in the back surface of the plate and extending from a central
region of the back surface to an outer peripheral region of the
back surface; a second recessed channel formed in the back surface
of the plate and extending from the central region of the back
surface to the outer peripheral region of the back surface; a first
plurality of apertures along the first recessed channel, each of
the first plurality of apertures extending through the plate from
the front surface to the first recessed channel; and a second
plurality of apertures along the second recessed channel, each of
the second plurality of apertures extending through the plate from
the front surface to the second recessed channel, wherein the first
recessed channel and the second recessed channel are intertwined,
and a surface of the first recessed channel and a surface of the
second recessed channel each further comprise an upper portion that
is disposed between a lower portion and the back surface, and the
lower portion having a rounded shape..Iaddend.
.Iadd.28. The gas distribution apparatus of claim 27, wherein the
rounded shape is a half-round shape or a half-elliptical
shape..Iaddend.
.Iadd.29. The gas distribution apparatus of claim 27, wherein the
first plurality of apertures extends from the lower portion of the
surface of the first recessed channel to the front
surface..Iaddend.
.Iadd.30. The gas distribution apparatus of claim 29, wherein the
second plurality of apertures extends from the lower portion of the
surface of the second recessed channel to the front
surface..Iaddend.
.Iadd.31. The gas distribution apparatus of claim 27, wherein each
aperture of the first plurality of apertures and the second
plurality of apertures comprises a first section having a first
diameter, a second section, and a third section that has a second
diameter, wherein the second section is between the first and third
sections and has a shape that tapers from the first diameter to the
second diameter..Iaddend.
Description
BACKGROUND
Embodiments of the invention generally relate to an apparatus and a
method for flowing a gas into a processing chamber. More
specifically, embodiments of the invention are directed to linear
flow apparatus for directing a flow of gas to a processing chamber
such as an atomic layer deposition chamber or chemical vapor
deposition chamber.
In the field of semiconductor processing, flat-panel display
processing or other electronic device processing, vapor deposition
processes have played an important role in depositing materials on
substrates. As the geometries of electronic devices continue to
shrink and the density of devices continues to increase, the size
and aspect ratio of the features are becoming more aggressive,
e.g., feature sizes of 0.07 .mu.m and aspect ratios of 10 or
greater. Accordingly, conformal deposition of materials to form
these devices is becoming increasingly important.
During an atomic layer deposition (ALD) process, reactant gases are
introduced into a process chamber containing a substrate.
Generally, a region of a substrate is contacted with a first
reactant which is adsorbed onto the substrate surface. The
substrate is then contacted with a second reactant which reacts
with the first reactant to form a deposited material. A purge gas
may be introduced between the delivery of each reactant gas to
ensure that the only reactions that occur are on the substrate
surface.
Gas distribution apparatus, sometimes shaped like and referred to
as showerheads, distribute processing gases to a substrate (also
referred to as a wafer) at close proximity. Gas distribution
apparatuses, including showerheads, have large volumes which can be
very difficult to clean or purge between gases. Any gases remaining
in the showerhead may react with subsequent processing gases. For
ALD processes, separation of gases is important within a gas
distribution apparatus, including showerheads, that relies on
alternating pulses of gases, for example, an A pulse, a B pulse, an
A pulse, and a B pulse type delivery. Therefore, there is an
ongoing need in the art for improved gas distribution apparatuses,
including showerheads, that are easy to clean/purge and provide a
uniform supply of gases to the substrate.
SUMMARY
One or more embodiments of the invention are directed to gas
distribution apparatuses for controlling flow of gas into a process
chamber. The apparatus comprises a delivery channel having an inlet
end, an outlet end, a length and a plurality of apertures spaced
along the length. An inlet on the inlet end of the delivery channel
is connectable to a gas source, wherein flow of the gas is
controllable by a gas valve in communication with the inlet. An
outlet on the outlet end of the delivery channel is connectable to
a vacuum source, wherein vacuum pressure through the outlet is
controllable by an outlet valve to provide a reduced pressure at
the outlet. A controller to regulate the flow of the gas through
the delivery channel and into the process chamber by opening and
closing the outlet valve during gas delivery and gas purging in the
channel to control the flow of gas through the apertures along the
length of the channel.
In some embodiments, a flow of gas through the gas distribution
apparatus has a more uniform conductance along an axial length of
the gas distribution apparatus than the flow of gas through a
similar gas distribution apparatus without the vacuum source
connected to the outlet. In one or more embodiments, when the gas
valve is closed, the gas is purged from the delivery channel faster
than a similar gas distribution apparatus without the vacuum
source.
In some embodiments, the delivery channel is a recessed channel in
a back side of a gas distribution plate and the plurality of
apertures extend through the gas distribution plate to a front side
of the gas distribution plate.
In one or more embodiments, the gas distribution plate is round and
the delivery channel forms a spiral shape with one of the inlet end
and outlet end is positioned in an outer peripheral region of the
gas distribution plate and the other of the inlet end and outlet
end positioned in a central region of the gas distribution plate.
In some embodiments, the inlet end is positioned at the outer
peripheral region of the gas distribution plate and the outlet end
is positioned at the central region of the gas distribution plate.
In one or more embodiments, the outlet end is positioned at the
outer peripheral region of the gas distribution plate and the inlet
end is positioned at the central region of the gas distribution
plate.
In some embodiments, there are two delivery channels recessed in
the back side of the gas distribution plate. In some embodiments,
each of the delivery channels forms a spiral shape with one of the
inlet end and outlet end positioned in an outer peripheral region
of the gas distribution plate and the other of the inlet end and
outlet end positioned in a central region of the gas distribution
plate. In one or more embodiments, the two delivery channels are
intertwined along the spiral shape. In certain embodiments, each
delivery channel has the inlet end positioned in the outer
periphery region of the gas distribution plate and the outlet end
positioned in the central region of the gas distribution plate. In
some embodiments, each delivery channel has the outlet end
positioned in the outer periphery region of the gas distribution
plate and the inlet end positioned in the central region of the gas
distribution plate. In one or more embodiments, the inlet end of
one delivery channel is positioned in the outer periphery region of
the gas distribution plate and the outlet end of the other delivery
channel is positioned in the outer periphery region of the gas
distribution plate.
In some embodiments, the gas distribution apparatus further
comprises a back cover on the back side of the gas distribution
plate, the back cover covering the recessed channel. In one or more
embodiments the delivery channel is a tubular spiral having a
substantially planar configuration. In some embodiments, the gas
distribution apparatus comprises a plurality of delivery channels,
each delivery channel extending substantially straight and
substantially parallel to adjacent delivery channels.
In one or more embodiments, more than one of the delivery channels
are connected to the inlet so that a gas flowing through the inlet
flows through each of the delivery channels. In some embodiments,
each of the delivery channels connected to the inlet merge and are
connected to one outlet. In some embodiments, each of the delivery
channels connected to the inlet has a separate outlet connected to
a separate outlet valve. In one or more embodiments, the controller
independently adjusts each of the outlet valves to maintain a
substantially uniform flow of gas through each of the delivery
channels. In an embodiment, the plurality of delivery channels are
shaped to form one or more of words or logos.
In some embodiments, the plurality of delivery channels are shaped
so that the hole pattern seen by a substrate is uniform across the
gas distribution apparatus.
Additional embodiments of the invention are directed to processing
chambers comprising the gas distribution apparatus described. In
some embodiments, the gas distribution apparatus comprises a
tubular spiral having a substantially planar configuration, the gas
distribution apparatus positioned between a substrate support and a
gas distribution plate.
Additional embodiments of the invention are directed to gas
distribution apparatus, comprising a gas distribution plate, a back
cover, an inlet, an outlet and a controller. A gas delivery channel
is recessed in a back side of a gas distribution plate. The
recessed gas delivery channel has an inlet end, an outlet end, a
length and a plurality of apertures spaced along the length
extending through the gas distribution plate to a front side of the
gas distribution plate so that gas flowing through the gas delivery
channel can pass through the apertures exiting the gas distribution
plate. The back cover is on the back side of the gas distribution
plate covering the recessed channel. The inlet is connected to the
inlet end of the gas delivery channel through the back cover. The
inlet is connectable to a gas source, wherein a flow of gas is
controllable by a gas valve in communication with the inlet. An
outlet is connected to the outlet end of the gas delivery channel
through the back cover. The outlet is connectable to a vacuum
source, wherein vacuum pressure through the outlet is controllable
by an outlet valve to provide a reduced pressure at the outlet. The
controller regulates the flow of gas through the gas delivery
channel and into a process chamber by opening and closing the
outlet valve during gas delivery and gas purging to control the
flow of gas through the apertures along the length of the
channel.
In some embodiments, the gas distribution plate is round and the
delivery channel forms a spiral shape with one of the inlet end and
outlet end is positioned in an outer peripheral region of the gas
distribution plate and the other of the inlet end and outlet end
positioned in a central region of the gas distribution plate. In
one or more embodiments, there are two delivery channels recessed
in the back side of the gas distribution plate, the two delivery
channels intertwined along the spiral shape.
Further embodiments of the invention are directed to gas
distribution apparatuses comprising a plurality of elongate
delivery channels. Each delivery channel extends from an inlet end
along a length to an outlet end and has a plurality of apertures
spaced along the length. The inlet end is connectable to a gas
source, wherein flow of gas is controllable by a gas valve in
communication with the inlet end. The outlet end is connectable to
a vacuum source, wherein vacuum pressure through the outlet end is
controllable by an outlet valve to provide a reduced pressure at
the outlet end. A plurality of elongate vacuum channels with each
channel extending along a length. A controller regulates the flow
of gas through the gas delivery channel and into a process chamber
by opening and closing the outlet valve during gas delivery and gas
purging to control the flow of gas through the apertures along the
length of the channel. The plurality of apertures of each delivery
channel are separated from the plurality of apertures of an
adjacent delivery channel by at least one elongate vacuum
channel.
BRIEF DESCRIPTION OF THE DRAWINGS
So that the manner in which the above recited features of the
invention are attained and can be understood in detail, a more
particular description of the invention, briefly summarized above,
may be had by reference to the embodiments thereof 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.
FIG. 1 shows a view of a gas distribution apparatus in accordance
with one or more embodiments of the invention;
FIG. 2 shows a view of a gas distribution apparatus in accordance
with one or more embodiments of the invention;
FIG. 3 shows a view of a processing chamber including one or more
gas distribution apparatus in accordance with one or more
embodiments of the invention;
FIG. 4 shows a top view of a gas distribution apparatus in
accordance with one or more embodiments of the invention;
FIG. 5 shows a cross-section of a perspective view of a gas
distribution apparatus in accordance with one or more embodiments
of the invention
FIG. 6 shows a perspective view of a gas distribution apparatus in
accordance with one or more embodiments of the invention;
FIG. 7 shows a bottom view of a gas distribution apparatus in
accordance with one or more embodiments of the invention;
FIG. 8 shows a partial cross-sectional view of a gas distribution
apparatus in accordance with one or more embodiments,
FIG. 9 shows a top view of a gas distribution apparatus in
accordance with one or more embodiments of the invention;
FIG. 10 shows a partial cross-sectional view of a gas distribution
apparatus in accordance with one or more embodiments of the
invention;
FIG. 11 shows a view of an exploded partial cross-sectional view of
a gas distribution apparatus in accordance with one or more
embodiments of the invention
FIG. 12 shows a cross-section of a perspective view of a gas
distribution apparatus in accordance with one or more embodiments
of the invention
FIG. 13 shows a perspective view of a gas distribution apparatus in
accordance with one or more embodiments of the invention;
FIG. 14 shows a bottom view of a gas distribution apparatus in
accordance with one or more embodiments of the invention;
FIG. 15 shows a perspective view of a gas distribution apparatus in
accordance with one or more embodiments of the invention;
FIG. 16A shows a partial cross-sectional view of a gas distribution
apparatus in accordance with one or more embodiments of the
invention;
FIG. 16B shows a partial cross-sectional view of a gas distribution
apparatus in accordance with one or more embodiments of the
invention;
FIG. 17 shows a gas distribution apparatus in accordance with one
or more embodiments of the invention;
FIG. 18 shows a gas distribution apparatus in accordance with one
or more embodiments of the invention;
FIG. 19 shows a gas distribution apparatus in accordance with one
or more embodiments of the invention;
FIG. 20 shows a gas distribution apparatus in accordance with one
or more embodiments of the invention;
FIG. 21 shows a gas distribution apparatus in accordance with one
or more embodiments of the invention;
FIG. 22A shows a portion of a back side of a gas distribution
apparatus in accordance with one or more embodiments of the
invention; and
FIG. 22B shows the front side of the gas distribution apparatus of
FIG. 22A.
DETAILED DESCRIPTION
Embodiments of the invention are directed to gas distribution
apparatus for use in chemical vapor deposition type processes. One
or more embodiments of the invention are directed to atomic layer
deposition processes and apparatus (also called cyclical
deposition) incorporating the gas distribution apparatus described.
The gas distribution apparatus described may be referred to as a
showerhead or gas distribution plate, but it will be recognized by
those skilled in the art that the apparatus does not need to be
shaped like a showerhead or plate. The terms "showerhead" and
"plate" should not be taken as limiting the scope of the
invention.
A first embodiment of the invention is directed to an apparatus
with a single spiral gas delivery channel. All gases flow
sequentially through the same channel. An inlet is on the outer
radial edge of the spiral, also referred to as the outer periphery,
and may be attached to a gas source. A vacuum attachment is
connected to the internal end of the spiral. The inlet and outlet
can be reversed, either the gas source can be connected to the
inside of the spiral with the outlet valve at the outside end of
the spiral. The first embodiment can be used with a sequence as
shown in Table 1.
TABLE-US-00001 TABLE 1 Step Gas Source Outlet Valve 1 Precursor A
Closed 2a Purge Closed 2b Purge Open 2c Purge Closed 3 Precursor B
Closed
A second embodiment has two spiral channels intertwined. Each
channel has a gas inlet on the outer radial end of the spiral and
an outlet valve on the inner radial end of each spiral. The inlet
and outlet can be reversed or mixed. The different channels can be
used for different precursors.
In a third set of embodiments, the channel is a linear gas line.
The linear gas line can take any suitable shape, not just linear.
There can be multiple linear gas lines for different precursors.
Some embodiments have multiple parallel paths for all gases in
sequence, where conductance of the gas channels are substantially
the same.
In one or more embodiments, in an individual channel, conductance
of the gas through the channel and through the apertures is
controlled by modulating or changing the vacuum pressure at the
outlet end. Changing the vacuum pressure in turn creates a unique
flow dynamic that cannot be achieved in conventional gas
distribution apparatus. In some embodiments, a more uniform gas
flow is provided along the length of each channel and through the
apertures spaced along the length of the channel. A uniform gas
flow according to one or more embodiments means that there is
substantially no dead space that inhibits flow or pumping of gasses
through the channel. The provision of a vacuum with or without a
valve on one end of the channel with a valve at the other end of
the channel permits rapid switching between different types of
gases, such as precursor or reactant gases.
In some embodiments, the vacuum at the end of the gas delivery
channel enables the rapid purging of gases from within the channel.
A purge gas source can be connected to the inlet of the gas
delivery channel and work cooperatively with the vacuum at the
outlet of the channel to even more rapidly remove the reactive
gases from the channel. Additionally, vacuum ports can be spaced
along the length of the gas delivery channel, not just at the end
of the channel.
Embodiments of the invention may be capable of increasing the
conductance of gas through the holes spaced along the gas delivery
channel. Without being bound by any particular theory of operation,
it is believed that controlling the vacuum pressure at the outlet
end, or in the middle, of the channel changes the flow dynamics
relative to a conventional showerhead or gas distribution
plate.
Referring to FIGS. 1 and 2, one or more embodiments are directed to
gas distribution apparatus 100 to deliver a gas to a process
chamber (not shown). The gas distribution apparatus 100 comprises a
delivery channel 102 with an inlet end 104 and an outlet end 106.
The delivery channel 102 has a plurality of apertures 108 spaced
along the length of the delivery channel 102. An inlet 110 is
connected to and in fluid communication with the inlet end 104 of
the delivery channel 102. An outlet 112 is connected to and in
fluid communication with the outlet end 106 of the delivery channel
102. The inlet 110 is adapted to be connected to a gas source and
may include an inlet valve 114 capable of controlling the flow of
gas into (or out of) the delivery channel 102 or completely cut off
the flow of gas. The outlet 112 is adapted to be connected to a
vacuum source and may include an outlet valve 116 capable of
controlling the flow of gas into (or out of) the delivery channel
102 or completely cut off the flow of gas. The outlet 112 is
connectable to a vacuum source (not shown) so that vacuum pressure
through the outlet 112 is controllable by the outlet valve 116 to
provide a reduced pressure at the outlet 112.
A controller 150 regulates the flow of the gas through the delivery
channel 102 and into the process chamber. The controller 150 does
this by opening or closing (or any point in between fully open and
fully closed) the outlet valve during gas delivery and gas purging.
This controls the flow of gas through apertures (seen, for example,
in FIG. 4) spaced along the length of the channel.
The cross-sectional shape of the delivery channel 102 can be
controlled such that gas flowing through the delivery channel
experiences minimal resistance to flow. In some embodiments, the
delivery channel 102 has a round or oval cross-sectional shape. In
one or more embodiments, the delivery channel 102 has a
cross-sectional shape sufficient such that bends, turns, twists,
etc. provide substantially no dead space.
The overall shape (as opposed to the cross-sectional shape) of the
delivery channel 102 can be modified as desired. For example, the
delivery channel 102 can be shaped to fit within specific areas or
to match the shape of a substrate. The delivery channel 102 can be,
for example, straight, round, square, oval, rectangular or oblong.
Additionally, the overall shape of the delivery channel can be made
up of repeating units, parallel, perpendicular or concentric to
each other. In one or more embodiments, the delivery channel has an
overall shape in which there is substantially no dead space to
inhibit gas flow or purging. As used in this specification and the
appended claims, the term "substantially no dead space" means that
the flow of gas, or purging, is inhibited by less than about 10% or
by less than about 5% due to dead space.
In some embodiments, the delivery channel 102 is a tubular spiral
having a substantially planar configuration. This particular shape
is exemplified by the embodiment shown in FIGS. 1 and 2. As used in
this specification and the appended claims, the term "substantially
planar configuration" means that the plurality of apertures 108 in
the delivery channel 102 are in mostly the same plane. The
embodiment shown in FIGS. 1 and 2 has a substantially planar
configuration because the apertures are coplanar, even though the
inlet end and outlet end, and the portions of the delivery channel
near the inlet end and outlet end are not coplanar with the
plurality of apertures.
The delivery channel 102 can be used for plasma processing. For
example, the delivery channel 102 can be polarized relative to
another portion of the processing chamber to ignite a plasma within
the chamber. The delivery channel 102 can be biased relative to a
portion of the chamber, or a portion of the chamber can be biased
relative to the delivery channel 102. For example, the delivery
channel 102 can be polarized relative to the pedestal, or the
pedestal can be polarized relative to the delivery channel. The
frequency of the plasma can be tuned as well. In one or more
embodiments, the plasma is at a frequency of about 13.56 MHz. In
some embodiments, the plasma is at a frequency of about 40 MHz, 50
MHz, 60 MHz, 70 MHz, 80 MHz, 90 MHz, 100 MHz, 110 MHz or 120
MHz.
Any suitable material can be used for the delivery channel,
showerhead or gas distribution apparatus. Suitable materials
include, but are not limited to stainless steel and inert
materials. In some embodiments, the delivery channel, showerhead or
gas distribution plate is made of stainless steel.
FIG. 3 shows a cross-section of a portion of a processing chamber
according to one or more embodiments. A gas distribution apparatus
100 is placed between a substrate support pedestal 302 and a gas
distribution plate 306. The substrate support pedestal 302 is shown
supporting a substrate 304. The substrate support pedestal 302 can
be stationary or rotating, or can be stationary for part of the
processing and rotating for part of the processing. A rotating
support pedestal 302 may allow for more uniform processing of a
substrate by minimizing different gas flow patterns that may occur
throughout the processing chamber. The support pedestal 302 of some
embodiments includes a heater or heating mechanism. The heater can
be any suitable type of heater including resistive heaters.
The gas distribution apparatus 100 is shown as a tubular spiral
with a substantially planar configuration. The substrate 304 can be
processed with either, or both, the gas distribution plate 306 and
the gas distribution apparatus 100. The gas distribution apparatus
100 can be shaped so that it does not substantially interfere with
gas flowing from the gas distribution plate 306. As used in this
specification and the appended claims, the term "substantially
interfere" means that the gas distribution apparatus 100 does not
interfere with more than about 30% of the gas flowing from the gas
distribution plate. For example, the front surface 308 of the gas
distribution plate 306 has a plurality of apertures 310 through
which gases flow. The gas distribution apparatus 100 can be shaped
to avoid blocking the apertures 310.
The delivery channel positioned like that of FIG. 3 can also be
used for plasma processing. The apparatus 100 can be polarized
relative to a portion of the chamber, or a portion of the chamber
can be polarized relative to the apparatus 100. For example, the
delivery channel apparatus 100 can be polarized relative to the
pedestal 302, or the pedestal 302 can be polarized relative to the
apparatus 100. In some embodiments, the apparatus 100 is polarized
relative to the gas distribution plate 306. In one or more
embodiments, the gas distribution plate 306 is polarized relative
to the pedestal 302 and gas flowing from the apparatus 100 forms
the plasma. The frequency of the plasma can be tuned as well. In
one or more embodiments, the plasma is at a frequency of about
13.56 MHz. In some embodiments, the plasma is at a frequency of
about 40 MHz, 50 MHz, 60 MHz, 70 MHz, 80 MHz, 90 MHz, 100 MHz, 110
MHz or 120 MHz.
FIGS. 4 through 7 show another embodiment of a gas distribution
apparatus 400 in which the delivery channel 402 is a recessed
channel in the back side 401 of a gas distribution plate 403. The
embodiment shown has a large inner section is recessed in the back
side 401 of the gas distribution plate 403 with the delivery
channel 402 recessed even further. This allows for the addition of
a back cover 407 which can be placed in the recessed area in the
back side 401 enclosing the delivery channel 402. The back cover
407, when inserted into the recessed back side 401 of certain
embodiments creates a substantially flush back side surface of the
gas distribution plate. It will be understood by those skilled in
the art that the back cover 407 does not need to fit within a
recessed area of the back side 401 of the gas distribution plate
403, but can also rest directly on the back side 401 of the gas
distribution plate 403. In embodiments of this sort, there is no
large recessed area with the delivery channels being further
recessed. Instead, the delivery channels are recessed directly into
the back side 401 of the gas distribution plate 403.
The back cover 407 may have openings to allow for the passage of
inlet and outlet tubes to allow for fluid communication with the
delivery channel 402. This can be seen in FIGS. 5 and 6. The inlet
and outlet tubes can be an integral part of the back cover 407, or
can be separate pieces connected to the back cover 407 in such a
manner as to prevent or minimize fluid leakage. A plurality of
apertures 408 extend through the gas distribution plate 403 to a
front side 405 of the gas distribution plate 403. These apertures
can be seen in FIGS. 4, 5 and 7. The plurality of apertures 408 can
be evenly spaced along the length of the delivery channel, or can
have varied spacing along the length of the channel. Variable
spacing may help produce a more uniform gas flow from the delivery
channel at points along the delivery channel. For example, in gas
delivery channel that has an elaborate shape, the spacing of the
apertures can varied along the length.
In the embodiment shown in FIGS. 4-7, the gas distribution plate
403 is round and the delivery channel 402 forms a spiral shape. The
inlet end 404 is denoted at the outside of the spiral in an outer
peripheral region 420 of the gas distribution plate 403 with the
outlet end 406 at the center of the spiral in a central region 422
of the gas distribution plate 403. It will be understood by those
skilled in the art that the inlet end 404 and outlet end 406 can be
reversed with the inlet end 404 being located at the center of the
spiral and the outlet end 406 at the outside of the spiral. In some
embodiments, one of the inlet end 404 and outlet end 406 is
positioned in an outer peripheral region 420 of the gas
distribution plate 403 and the other of the inlet end 404 and
outlet end 406 is positioned in a central region 422 of the gas
distribution plate 403. In one or more embodiments, the inlet end
404 is positioned at the outer peripheral region 420 of the gas
distribution plate 403 and the outlet end 406 is positioned at the
central region 422 of the gas distribution plate 403. In certain
embodiments, the outlet end 406 is positioned at the outer
peripheral region 420 of the gas distribution plate 403 and the
inlet end 404 is positioned at the central region 422 of the gas
distribution plate 403.
In FIGS. 5 and 6, the inlet end 404 and outlet end 406 are
illustrated as a small tube extending from the back cover 407 of
the gas distribution plate 403. The tubes extend between the inlet
410 and the back cover 407 through an inlet valve 414. Another tube
can extend between the outlet 412 and the back cover 407 through
the outlet valve 416. The tubes can be connected to the back cover
407 by any suitable connection known to those skilled in the art
and may be sealed to prevent leakage of fluid flowing through the
tube into the delivery channel 402. Suitable sealing devices
include, but are not limited to, o-rings positioned between a
flange 424 and the back cover 407. The flange 424 can be integrally
formed with the tube or can be a separate piece that holds the tube
to the back cover. The flange 424 can be connected to the back
cover 407 by any suitable mechanical connection, including but not
limited to, screws.
FIG. 8 shows a cross-sectional view of one portion of a delivery
channel 402 and an aperture 408 in a gas distribution plate 403 in
accordance with one or more embodiments of the invention. It will
be understood by those skilled in the art that the delivery channel
and apertures described in FIG. 8 are merely illustrative and
should not be taken as limiting the scope of the invention. Those
skilled in the art will understand that there are other ways of
creating flow from the delivery channel 402 through the gas
distribution plate 403. The delivery channel 402 shown in FIG. 8
has two portions, an upper portion 832 and a lower portion 830.
While these portions are shown as separate areas, it will be
understood that there can be a seamless transition between the
upper portion 832 and the rounded lower portion 830.
Additionally, it will be understood that the upper portion 832 is
optional and does not need to be included in the delivery channel
402. When there is no upper portion 832, the lower portion 830 is
the only portion. Thus, the delivery channel can have any suitable
shape. In some embodiments, the shape of the delivery channel is
such that there is substantially no interference with the flow of
gases through the channel.
The upper portion 832 can have my suitable shape. In the embodiment
shown in FIG. 8, the upper portion 832 has walls which extend
normal to the surface of the back side 401 of the gas distribution
plate 403. However, it will be understood that the upper portion
832 can have walls which are canted from square to the back side
401. The canting can provide a larger opening at the back side 401
of the gas distribution plate 403, tapering to a smaller opening.
Additionally, the canting can provide a smaller opening at the back
side 401, tapering to a larger opening. The length of the upper
portion 832 can be modified as necessary.
In some embodiments, the upper portion has sides which are
substantially perpendicular to the back side 401 of the gas
distribution plate 403 and extend a length L below the surface of
the back side 401 in the range of about 0.01 inch to about 0.3
inches. As used in this specification and the appended claims, the
term "substantially perpendicular to" means that walls of the upper
portion have an angle relative to the back side of the gas
distribution plate in the range of about 85 degrees to about 95
degrees. In some embodiments, the upper portion extends below the
surface of the back side to a length L in the range of about 0.02
inches to about 0.2 inches, or in the range of about 0.05 inches to
about 0.15 inches, or in the range of about 0.08 inches to about
0.12 inches. In one or more embodiments, the upper portion extends
below the surface of the back side to a length about 0.1
inches.
The rounded lower portion 830 can have any suitable cross-section
including, but not limited to, half-round and half-elliptical. The
width of the rounded lower portion, also referred to as the
diameter of the rounded lower portion, can be modified as
necessary. The width of the upper portion can be modified as
necessary. The diameter of the delivery channel, in general, can
have an impact of the number of loops in the spiral. In some
embodiments, as shown in FIG. 8, the width of the upper portion is
about equal to the diameter of the lower portion. The delivery
channel of various embodiments has a diameter in the range of about
0.3 inches to about 0.45 inches, or in the range of about 0.325
inches to about 0.425 inches, or in the range of about 0.35 inches
to about 0.40 inches. In one or more embodiments, the delivery
channel has a diameter of about 0.375 inches.
The specific shape of the apertures 408 can vary depending on the
desired flow of gases through the apertures. In the embodiment of
FIG. 8, the aperture 408 has three distinct sections; a first
section 834, a second section 836 and a third section 838. Again,
the number of sections and the shape of the sections are merely
illustrative of one embodiment and should not be taken as limiting
the scope of the invention. The first section 834 extends from the
rounded lower portion 830 of the delivery channel 402 toward the
front side 405 of the gas distribution plate 403. The first section
834 has a first diameter D1. The second section 836 extends from
the first section 834 toward the front side 405 and has a diameter
which tapers from the first diameter D1 to a second diameter D2,
which is generally smaller than the first diameter. The third
section 838 extends from the end of the second section 836 and ends
at the front side 405 of the gas distribution plate 403. At the
intersection of the third section 838 and the front side 405, a
hole 840 is formed. Gases flowing through the delivery channel 402
exit the gas distribution plate 403 through this hole 840 into the
processing chamber. The hole 840 has about the same diameter as the
second diameter D2. In various embodiments, the diameter of the
hole 840 is in the range of about 0.01 inches to about 0.25 inches,
or in the range of about 0.02 inches to about 0.2 inches, or in the
range of about 0.03 inches to about 0.15 inches or in the range of
about 0.04 inches to about 0.1 inches. In some embodiments, the
hold 840 has a diameter less than about 0.1 inches, or less than
about 0.08 inches, or less than about 0.06 inches, or less than
about 0.04 inches, or less than about 0.02 inches, or less than
about 0.01 inch.
As the delivery channel spirals from the outer peripheral edge of
the gas distribution plate to the central region, or vice versa, a
seeming plurality of adjacent channels are observable in
cross-section, even though it may be a single channel. FIG. 5 shows
this seeming plurality of channels. The channels, or separation
between loops of the spiral, are separated by a distance. In some
embodiments, the distance between the channels, or the loops of the
single channel, measured from centers, are in the range of about
0.375 inches to about 0.475 inches, or in the range of about 0.40
inches to about 0.45 inches, or in the range of about 0.41 inches
to about 0.43 inches. In one or more embodiments, the average
distance between centers of the adjacent channels is about 0.42
inches.
The length of the gas channel shown in FIGS. 4 to 7 can vary
depending on a number of factors, including, but not limited to,
the diameter of the channel and the distance between the adjacent
channels. In various embodiments, the delivery channel has a length
in the range of about 140 inches to about 340 inches, or in the
range of about 180 inches to about 300 inches, or in the range of
about 200 inches to about 280 inches, or in the range of about 220
inches to about 260 inches. In one or more embodiments, the
delivery channel has a length of about 240 inches.
The number of apertures are also dependent on a number of factors,
including but not limited to, the length of the delivery channel
and the spacing of the apertures. In some embodiments having a
single spiral channel, there are in the range of about 300 and 900
apertures, or in the range of about 400 to about 800 apertures, or
in the range of about 500 to about 700 apertures. In various
embodiments, there are greater than about 300, 400, 500, 600, 700
or 800 apertures along the length of the channel. In one or more
embodiments, there are about 600 apertures along the length of the
delivery channel.
In an embodiment, as shown in FIG. 4, the gas delivery plate 403
comprises a single delivery channel 402 in a back side of the gas
delivery plate 403. The delivery channel 402 has an inlet end 404
located in an outer peripheral region 420 of the gas distribution
plate 403. The delivery channel 402 and follows an inward spiral
path from the inlet end 404 to an outlet end 406 located in a
central region 422 of the gas distribution plate 403. The delivery
channel 402 has an overall length, defined as the distance between
the inlet end 404 and the outlet end 406 of about 240 inches. A
plurality of apertures 408 are spaced along the overall length of
the delivery channel 402. Along the overall length of the delivery
channel 403 there are in the range of about 500 apertures and about
700 apertures. The delivery channel 403 has an average diameter of
about 0.375 inches and adjacent portions of the spiral channel are
spaced about 0.42 inches on center.
Some embodiments of the invention include more than one delivery
channel 402. These multiple channels can be intertwined or separate
depending on the needs of the processing system. Some channels can
be recessed into a gas distribution plate as shown in FIG. 4, or
can be individual tubes as shown in FIG. 1. In some embodiments,
there are a combination of individual tubes and recessed channels.
An exemplary embodiment of the sort is shown in FIG. 3, where the
gas distribution plate may have at least one recessed delivery
channel therein and an additional delivery channel is positioned
between the gas distribution plate and the substrate surface.
Another embodiment of the invention is shown in FIGS. 9 through 14.
A gas distribution apparatus 900 comprises two delivery channels
902a, 902b recessed in the back side 901 of a gas distribution
plate 903. It will be understood that the delivery channels do not
need to be recessed into the back of a gas distribution plate, but
can be individual tubes, as shown in FIGS. 1 and 15. The first
delivery channel 902a has a first inlet end 904a and a first outlet
end 906a and a plurality of first apertures 908a spaced along the
length of the first delivery channel 902a. The second delivery
channel 902b has a second inlet end 904b, a second outlet end 906b
and a plurality of second apertures 908b spaced along the length of
the second delivery channel 902b.
A first inlet 910a is connected to the first inlet end 904a of the
first delivery channel 902a. The first inlet 910a is adapted to be
connected to a gas source. A first outlet 912a is connected to the
first outlet end 906a of the first delivery channel 902a. The first
outlet 912a is adapted to be connected to a vacuum source. A second
inlet 910b is connected to the second inlet end 904b of the second
delivery channel 902b. The second inlet 910b is adapted to be
connected to a gas source. A second outlet 912b is connected to the
second outlet end 906b of the second delivery channel 902b. The
second outlet 912a is adapted to be connected to a vacuum
source.
In the embodiment shown in FIGS. 9 to 14, each of the delivery
channels 902a, 902b form a spiral shape. One or more embodiments,
as that shown in the Figures, have the two delivery channels 902a,
902b intertwined along the length of the spiral shape. It will be
understood by those skilled in the art that the two delivery
channels 902a, 902b can have shapes other than spiral and do not
need to intertwine. In certain embodiments, the plurality of first
apertures 908a and second apertures 908b extend through the gas
distribution plate 903 to the front side 905 of the gas
distribution plate 903.
In some embodiments, each of the delivery channels 902a, 902b form
a spiral shape with one of the inlet end 904a, 904b and outlet end
906a, 906b positioned in an outer peripheral region 920 of the gas
distribution plate 903 and the other of the inlet end 904a, 904b
and outlet end 906a, 906b positioned in a central region 922 of the
gas distribution plate 903. In one or more embodiments, the inlet
ends 904a, 904b of both channels 902a, 902b is positioned in the
outer peripheral region 920 and the inlet ends 904a, 904b of both
channels 902a, 902b are positioned in the central region 922 of the
gas distribution plate 903. In certain embodiments, the inlet ends
904a, 904b of both channels 902a, 902b is positioned in the central
region 922 and the inlet ends 904a, 904b of both channels 902a,
902b are positioned in the outer peripheral region 920 of the gas
distribution plate 903. In one or more embodiments, one or the
inlet ends 904a, 904b is positioned in the outer peripheral region
920 and the other inlet end 904b, 904a is positioned at the central
region 922, with the outlet ends 906a, 906b at the other end of
each individual delivery channel 902a, 902b.
FIG. 11 shows a back cover 907 for the gas distribution plate 903
shown in FIG. 9. There are four holes (not numbered) located in the
back cover 907 which align approximately with the inlet ends 904a,
904b and outlet ends 906a, 906b of the delivery channels 902a,
902b. The holes can be used to provide an access point for
connected in the inlet 910a, 910b and outlet 912a, 912b to the
channels 902a, 902b. In some embodiments, there inlet 910a, 910b
and outlet 912a, 912b are integrally formed with the back cover
907. Additionally, as seen in FIGS. 12 and 13, there can be one or
more inlet valves 914a, 914b and outlet valves 916a, 916b
FIGS. 12 and 13 show perspective views of a gas distribution
apparatus 900 in accordance with various embodiments of the
invention. The inlets 910a, 910b are shown connected to the back
cover 907 with a flange 924a, 924b. The connection and gas-tight
sealing of the flange 924a, 924b can be accomplished by any
suitable mechanism and techniques as known to those skilled in the
art. The outlets 912a, 912b can also be connected to the back cover
907 with a flange or with a block connection 925. The block 925 can
be integrally formed with the back cover 907 or can be a separate
piece. The block 925 may provide additional support and space for
the outlet valves 916a, 916b, allowing the connecting tubes to
protrude from the back cover 907 at an angle. Although the inlets
910a, 910b and inlet valves 914a, 914b are shown on the outside
peripheral region 920 of the gas distribution plate 903 and the
outlets 912a, 912b and outlet valves 916a, 916b are shown at the
central region 922 of the gas distribution plate 903, it will be
understood that these components can be reversed or intermixed and
that the drawings are merely illustrative of one embodiment.
As the delivery channels spiral from the outer peripheral edge of
the gas distribution plate to the central region, or vice versa, a
seeming plurality of adjacent channels are observable in
cross-section. With the spirals intertwined, the gas in every
adjacent channel is from the other inlet 910a, 910b. The channels
are separated by a distance from the adjacent channels. In some
embodiments, the distance between the channels, measured from the
center of the channel, are in the range of about 0.375 inches to
about 0.475 inches, or in the range of about 0.40 inches to about
0.45 inches, or in the range of about 0.41 inches to about 0.43
inches. In one or more embodiments, the average distance between
centers of the adjacent channels is about 0.42 inches.
The length of the gas channel shown in FIGS. 9-14 can vary
depending on a number of factors, including, but not limited to,
the diameter of the channel and the distance between the adjacent
channels. In various embodiments, each of the delivery channels has
a length in the range of about 70 inches to about 170 inches, or in
the range of about 90 inches to about 150 inches, or in the range
of about 100 inches to about 140 inches, or in the range of about
110 inches to about 130 inches. In one or more embodiments, the
delivery channel has a length of about 120 inches.
The number of apertures are also dependent on a number of factors,
including but not limited to, the length of the delivery channel
and the spacing of the apertures. In some embodiments having a
single spiral channel, there are in the range of about 150 and 450
apertures, or in the range of about 200 to about 400 apertures, or
in the range of about 250 to about 350 apertures. In various
embodiments, there are greater than about 150, 200, 250, 300, 350
or 400 apertures along the length of the channel. In one or more
embodiments, there are about 300 apertures along the length of each
of the delivery channels.
The apparatus shown in FIGS. 4 through 14 can be used for plasma
processing. For example, the delivery channel, gas distribution
apparatus or showerhead can be polarized relative to another
portion of the processing chamber to ignite a plasma within the
chamber. The delivery channel, gas distribution apparatus or
showerhead can be polarized relative to a portion of the chamber,
or a portion of the chamber can be biased relative to the delivery
channel, gas distribution apparatus or showerhead. For example, the
delivery channel, gas distribution apparatus or showerhead can be
polarized relative to the pedestal, or the pedestal can be
polarized relative to the delivery channel, gas distribution
apparatus or showerhead. The frequency of the plasma can be tuned
as well. In one or more embodiments, the plasma is at a frequency
of about 13.56 MHz. In some embodiments, the plasma is at a
frequency of about 40 MHz, 50 MHz, 60 MHz, 70 MHz, 80 MHz, 90 MHz,
100 MHz, 110 MHz or 120 MHz.
In some embodiments of the apparatus exemplified by FIGS. 4 through
14, there is an insulating material (not shown) positioned between
the back cover and the main body portion of the gas distribution
apparatus (i.e., the portion including the gas delivery channel).
This insulating material provides electrical isolation between the
back cover and the main body portion of the gas distribution
apparatus so that the back cover can be polarized relative to the
main body portion. Doing so may allow for the ignition of a plasma
within the gas distribution apparatus, or within the delivery
channels. The plasma can then be flowed through the plurality of
apertures into the processing region of the processing chamber, the
processing region being the region between the gas distribution
apparatus and the pedestal. This configuration may be referred to
as a remote plasma because the plasma is formed (e.g., ignited)
outside of the processing region.
FIGS. 15, 16A and 16B show another exemplary embodiment of a gas
distribution apparatus 1500. The gas distribution apparatuses shown
are particularly useful for spatially separated atomic layer
deposition processes in which different portions of the substrate
are simultaneously exposed to different deposition gases and the
substrate 1544 is moved relative to the gas distribution apparatus
so that all parts of the substrate are exposed sequentially to each
of the deposition gases. In these embodiments, the gas distribution
apparatus 1500 comprises a plurality of delivery channels 1502,
each delivery channel 1502 extending substantially straight and
substantially parallel to adjacent delivery channels. Each of the
delivery channels 1502 has an inlet end 1504 and an outlet end 1506
with a plurality of spaced apertures 1508 there between.
The gas distribution apparatus shown in FIGS. 15, 16A and 16B have
a plurality of elongate delivery channels 1502 and a plurality of
elongate vacuum channels 1550. Each of the delivery channels 1502
and vacuum channels 1550 are connected to a output channel 1552 at
the front face of the gas distribution apparatus. Each of the
delivery channels 1502 is adapted to flow one or more of a reactive
gas and a purge gas. Each delivery channel 1502 is connected to an
output channel 1552 by a plurality of spaced apertures 1508. Each
of the vacuum channels 1550 is connected to an inlet channel 1554
by a plurality of spaced vacuum apertures 1558. The plurality of
apertures 1508 of each delivery channel 1502 are separated from the
plurality of apertures 1508 of each adjacent delivery channel 1502
by at least one plurality of vacuum apertures 1558 from a vacuum
channel 1550.
In the embodiment shown in FIG. 16A, each of the central vacuum
channels 1550 (not the end vacuum channels) are connected to two
inlet channels 1554 by vacuum apertures 1508. The end vacuum
channels 1550 are only connected to a single inlet channel 1554. It
should be understood that this is merely exemplary and should not
be taken as limiting the scope of the invention. Each inlet channel
1554 can have a dedicated vacuum channel 1550, or a single vacuum
channel 1550 can be connected to more than two inlet channels 1554
through a plurality of vacuum apertures 1508.
While each of the delivery channels appear the same, there can be a
different gas flowing through each. For example, purge channels
(denoted P) may have a purge gas flowing there through, each of the
first reactive gas channels (denoted A) may have a first reactive
gas flowing there through and each of the second reactive gas
channels (denoted B) may have a second reactive gas flowing there
through. The vacuum channels (denoted V) are connected to a vacuum
source. With reference to FIG. 16A, a substrate 1544 (or more
specifically, a fixed point on a substrate) moving from left to
right would encounter in order a vacuum gas channel, a purge gas
channel, a vacuum gas channel, a first reactive gas channel, a
vacuum gas channel, a purge gas channel, a vacuum gas channel, a
second reactive gas channel, a vacuum gas channel, etc., depending
on the size of the gas distribution plate.
The use of the delivery channels with inlet and outlet ends allows
for the rapid exchange of gas within the delivery channel. For
example, after the substrate (or fixed point on the substrate) is
exposed to the second reactive gas channel (denoted B), the outlet
end of the delivery channel can be opened, allowing the gas within
the channel to be removed, and a different reactive gas (e.g., gas
C) can then be flowed into the delivery channel. Thus, when the
substrate passes back under that gas channel the substrate will be
exposed to gas C instead of gas B. While this example has been made
with respect to a second reactive gas, it will be understood by
those skilled in the art that an of the gas delivery channels
(first reactive gas, second reactive gas or purge gas) can be
purged and replaced with a different gas.
The delivery channel of FIGS. 15, 16A and 16B can be used for
plasma processing as well. The gas distribution apparatus 1500 can
be biased relative to another portion of the chamber. For example,
the gas distribution apparatus 1500 can be polarized relative to
the pedestal, or the pedestal can be polarized relative to the gas
distribution apparatus. The frequency of the plasma can be tuned as
well. In one or more embodiments, the plasma is at a frequency of
about 13.56 MHz. In some embodiments, the plasma is at a frequency
of about 40 MHz, 50 MHz, 60 MHz, 70 MHz, 80 MHz, 90 MHz, 100 MHz,
110 MHz or 120 MHz.
FIG. 16B shows an embodiment of a single delivery channel 1502 and
a single vacuum channel 1550. Each of the delivery channel 1502 and
vacuum channel 1550 have two sets of apertures extending therefrom.
In the case of the vacuum channel 1550, one set of apertures 1558a
connect to a first inlet channel 1554a and the other set of
apertures 1558b connects to a second inlet channel 1554b. The
delivery channel 1502, on the other hand, has two sets of apertures
1508 extending to a single output channel 1552.
In one or more embodiments, the gas distribution apparatus includes
more than one outlet connected to a vacuum source. FIG. 17 shows a
spiral shaped gas distribution apparatus 1700 which is similar to
the apparatus 100 shown in FIG. 1. The apparatus includes a
delivery channel 1702 with an inlet end 1704 and an outlet end
1706. An inlet 1710 is connected to and in communication with the
inlet end 1704 of the delivery channel 1702. An outlet 1712 is
connected to and in communication with the outlet end 1706 of the
delivery channel 1702. The inlet 1710 is connectable to a gas
source and may include an inlet valve 1714 that can control the
flow of gas into (or out of) the delivery channel 1702 or
completely cut off the flow of gas. The outlet 1712 is connectable
to a vacuum source (not shown) and may include an outlet valve 1716
that can control the flow of gas out of (or into) the delivery
channel 1702 or completely cut off the vacuum source from the
delivery channel 1702. An intermediate outlet 1742 which is
connectable to the vacuum source (not shown) is position along the
length of the delivery channel 1702. The intermediate outlet 1742
shown is connected to the delivery channel 1702 at about the middle
of the length of the channel 1702 and coupled to the delivery
channel 1702 through an intermediate outlet 1740. The intermediate
outlet 1742 may include an intermediate outlet valve 1744 that can
control the flow of gas out of (or into) the delivery channel 1702
or completely cut off the vacuum source from the delivery channel
1702. The inlet valve 1714 of the inlet 1710, the outlet valve 1716
of the outlet 1712 and the intermediate outlet valve 1744 of the
intermediate outlet 1740 are connected to a controller 1750. The
controller is capable of independently opening or closing any or
all of the valves to adjust the pressure of gases flowing through
the delivery channel 1702 or purge the delivery channel 1702 of an
existing gas. For example, Table 2 shows a processing sequence that
may be used with the embodiment shown in FIG. 17. It will be
understood by those skilled in the art that this is merely an
example and should not be taken as limiting the scope of the
invention.
TABLE-US-00002 TABLE 2 Intermediate Step Gas Source Outlet valve
Outlet valve 1a Precursor A Closed Partially Open 1b Precursor A
Closed Closed 2a Purge Open Closed 2b Purge Open Open 2c Purge Open
Closed 3a Precursor B Partially Open Closed 3b Precursor B Closed
Closed
The valves shown in Table 2 are open, closed or partially open at
any point during the processing. In Step 3a, after purging the
delivery channel of Precursor A, the intermediate outlet valve is
partially open to accelerate the flow of Precursor B through the
delivery channel and then closed in Step 3b. This is merely one
possible sequence that can be used and should not be taken as
limiting the scope of the invention.
The embodiment shown in FIG. 17 effectively includes two outlets,
one at the end of the delivery channel and one in the middle. Those
skilled in the art will understand that there can be any number of
outlets spaced along the length of the delivery channel and at any
position along the length of the channel. For example, the
intermediate outlet 1740 could be positioned at 1/3 of the length
of the channel. Additionally, there can be any number of outlets.
For example, the delivery channel may have four outlets, one at the
end and one positioned at each of 1/4, 1/2 and 3/4 of the length of
the delivery channel. In another example, the delivery channel
includes four outlets, one at the end and one position at each of
1/4, 3/4 and 9/10 of the length of the delivery channel. In some
embodiments, the delivery channel includes 2, 3, 4, 5, 6, 7, 8, 9,
10 or 11 total outlets (including an outlet at the outlet end of
the channel).
FIG. 18 shows another embodiment of the invention in which the gas
distribution apparatus 1800 includes a multipath delivery channel
1802. Here, the apparatus 1800 includes a delivery channel 1802
with an inlet end 1804 and an outlet end 1806. An inlet 1810 is
connected to and in communication with the inlet end 1804 of the
delivery channel 1802. An outlet 1812 is connected to and in
communication with the outlet end 1806 of the delivery channel
1802. The inlet 1810 is connectable to a gas source (not shown) and
may include an inlet valve 1814 that can control the flow of gas
into (or out of) the delivery channel 1802 or completely cut off
the flow of gas. The outlet 1812 is connectable to a vacuum source
(not shown) and may include an outlet valve 1816 that can control
the flow of gas out of (or into) the delivery channel 1802 or
completely cut off the vacuum source from the delivery channel
1802. The delivery channel 1802 splits near the inlet end 1804 into
three separate channels 1802a, 180b, 1802c and merges back into a
single channel near the outlet end 1806. A plurality of apertures
1808 are spaced along the length of each of the channels so that a
single gas flowing into the inlet 1810 can be directed along
multiple paths and connected to a single outlet 1812. The apertures
1808 can be evenly spaced or unevenly spaced along the length of
the channel 1802.
The embodiment shown splits the delivery channel into three
separate channels along the length of the channel. However, it will
be understood by those skilled in the art that this is merely
exemplary and that the delivery channel can be split into any
number of channels. In some embodiments, the delivery channel
splits into 2, 3, 4, 5, 6, 7, 8, 9 or 10 separate delivery
channels. Additionally, the delivery channel can split multiple
time along the length of the channel. For example, the channel can
split into two, merge into one and then split into 3 along the
length of the channel.
The flow of gas through the multi-channel gas distribution
apparatus shown in FIG. 18 may not be uniform among the three
channels. The uniformity of gas flow between the channels can be
affected by a number of factors including, but not limited to, gas
pressure, vacuum pressure, temperature, flow rate and from static
pressure drops along the length. FIG. 19 shows another embodiment
of a gas distribution apparatus 1900 in which the delivery channel
1902 splits into three separate channels 1902a, 1902b, 1902c each
with its own outlet valve 1912a, 1912b, 1912c. The apparatus 1900
shown includes an inlet end 1904 connected through an inlet valve
1914 to an inlet 1910. The delivery channel 1902 includes a
plurality of apertures 1908 spaced along the length of each of the
separate channels 1902a, 1902b, 1902c. The apertures can be evenly
spaced or unevenly spaced along the length of the channels. Each
channel has a separate outlet 1912a, 1912b, 1912c with separate
outlet valves 1916a, 1916b, 1916c. Each of the outlet valves 1916a,
1916b, 1916c is connected to a controller 1950 that can
independently control each of the outlet valves 1916a, 1916b,
1916c. In this embodiments, the controller 1950 can set the outlet
valves to closed, fully open, or at any point in between. For
example, if the flow of gas through one of the channels is lower
than the others, the controller 1950 may open the outlet valve of
that channel to accelerate the flow or may open the outlet valves
of the other channels to accelerate flow and cause less gas to exit
the channels through the apertures to cause a more uniform
flow.
Multiple separate channels can also be employed. FIG. 20 shows an
embodiment of a gas distribution apparatus 2000 with five separate
gas delivery channels 2002a, 2002b, 2002c, 2002d, 2002e. Each of
the delivery channels 2002a, 2002b, 2002c, 2002d, 2002e includes an
inlet valve 2014a, 2014b, 2014c, 2014d, 2014e and an outlet valve
2016a, 2016b, 2016c, 2016d, 2016e. Four spiral shaped delivery
channels 2002a-d are shown leaving a void area 2060 at the center
of the four channels. The fifth delivery channel 2002e passes
between the spirals and oscillates in the void area 2060 to prevent
dead space in the gas flow. The fifth delivery channel 2002e is
shown with an intermediate outlet valve 2044. Each of the delivery
channels can be configured to deliver the same gas, or can deliver
separate gases.
In one embodiment, the five channels cover a single substrate and
each channel delivers the same reactive gas. The substrate may be
rotated beneath the delivery channels, or the channels may rotate
or oscillate over the substrate. In another embodiment, alternative
delivery channels (e.g., 2002a, 2002c) can deliver a first reactive
gas and the other channels (e.g., 2002b, 2002d) can deliver a
second reactive gas. The fifth channel 2002e can be configured to
deliver an inert gas to form a curtain between the separate
channels to separate the gases and prevent gas-phase reactions.
Rotating the substrate beneath these channels would expose
alternating quarters to the same gas followed by the second
reactive gas to deposit a film. In this embodiment, the portion of
the substrate in the void area 2060 would not have a deposited
layer.
In another embodiment, each of the channels can deliver the same
gas but be sized so that a single substrate would be covered by a
single delivery channel allowing the processing of multiple
substrates by moving the substrates from one delivery channel to
the adjacent channel. Each channel can be configured to deliver the
same gas or separate gases and the fifth channel can be configures
to deliver an inert gas to form a curtain separating the reaction
regions adjacent the delivery channels. The fifth delivery channel,
and any other gas delivery channel described herein can have
multiple inlets and a single outlet, or multiple outlets. For
example the fifth delivery channel shown may have an inlet at
either end and a single outlet in the middle to create a stronger
gas curtain to separate the other delivery channels.
Again, the shape and number of outlets can vary depending on the
desired use. The spiral shape shown in FIG. 20 is merely exemplary
and should not be taken as limiting the scope of the invention. The
shape of the gas delivery channel(s) can be modified for a number
of reasons. In some embodiments, the gas delivery channel is shaped
for spell words (e.g., "Applied Materials") or form a logo. For
example, FIG. 21 shows three delivery channels 2102a, 2102b, 2102c
roughly forming the logo of Applied Materials, Inc. of Santa Clara,
Calif. The first gas delivery channel 2102a and second gas delivery
channel 2102b each have a single inlet valve 2114a, 2114b and a
single outlet valve 2116a, 2116b. The third gas delivery channel
2102c has a single inlet valve 2114c and two outlet valves 2116c,
2116d. Along the length, the third gas delivery channel 2102c
splits into two channels, reforms into a single channel and then
splits into two channels again. In another embodiment, inlet valves
and outlet valves of the third delivery channel are reversed so
that there are two inlet valves and a single outlet valve.
The gas flows coming from the surface of the gas distribution
apparatus seen by the substrate can be uniform or striated. For
example, a substrate passing beneath the dual spiral gas
distribution apparatus shown in FIG. 9 will see alternating rings
of gases. In some embodiments, the plurality of delivery channels
are shaped so that the hole pattern seen by a substrate is uniform
across the gas distribution apparatus. FIGS. 22A and 22B show part
an embodiment of a gas distribution apparatus 2203 in which the gas
flows seen by a substrate would be uniform. FIG. 22A shows the back
side 2201 of a gas distribution apparatus 2203 with a plurality of
alternating gas channels 2202a, 2202b. The gas channels 2202a,
2202b undulate with the holes 2208a, 2208b spaced along the length
of the gas channels so that hole 2208 pattern seen on the front
side 2205 in FIG. 22B is uniform. Additionally, the gas flows seen
by the substrate are uniform because there is a uniform
distribution of holes across the gas distribution apparatus front.
Looking at FIG. 22B, the top row of holes 2208 would alternate
between the first gas and the second gas, with the next row having
the reverse pattern. Thus, of the twelve holes 2208 shown, the
first gas will flow out of six of the holes and the second gas will
flow out of the other six holes.
There can be multiple inlet valves 2214a, 2214b, as shown in FIG.
22A, or can be a single valve split into multiple channels.
Additionally, there can be multiple outlet valves 2216a, 2216b, as
shown in FIG. 22B, or there can be a single outlet valve joining
each of the channels.
The gas distribution apparatus described can be used to form one or
more layers during a plasma enhanced atomic layer deposition
(PEALD) process. In some processes, the use of plasma provides
sufficient energy to promote a species into the excited state where
surface reactions become favorable and likely. Introducing the
plasma into the process can be continuous or pulsed. In some
embodiments, sequential pulses of precursors (or reactive gases)
and plasma are used to process a layer. In some embodiments, the
reagents may be ionized either locally (i.e., within the processing
area) or remotely (i.e., outside the processing area). Remote
ionization can occur upstream of the deposition chamber such that
ions or other energetic or light emitting species are not in direct
contact with the depositing film. In some PEALD processes, the
plasma is generated external from the processing chamber, such as
by a remote plasma generator system. The plasma may be generated
via any suitable plasma generation process or technique known to
those skilled in the art. For example, plasma may be generated by
one or more of a microwave (MW) frequency generator or a radio
frequency (RF) generator. The frequency of the plasma may be tuned
depending on the specific reactive species being used. Suitable
frequencies include, but are not limited to, 2 MHz, 13.56 MHz, 40
MHz, 60 MHz and 100 MHz. Although plasmas may be used during the
deposition processes disclosed herein, it should be noted that
plasmas may not be required.
According to one or more embodiments, the gas distribution
apparatus can be used to subject a substrate to processing prior to
and/or after forming the layer. This processing can be performed in
the same chamber or in one or more separate processing chambers. In
some embodiments, the substrate is moved from the first chamber to
a separate, second chamber for further processing. The substrate
can be moved directly from the first chamber to the separate
processing chamber, or it can be moved from the first chamber to
one or more transfer chambers, and then moved to the desired
separate processing chamber. Accordingly, the processing apparatus
may comprise multiple chambers in communication with a transfer
station. An apparatus of this sort may be referred to as a "cluster
tool" or "clustered system", and the like.
Generally, a cluster tool is a modular system comprising multiple
chambers which perform various functions including substrate
center-finding and orientation, degassing, annealing, deposition
and/or etching. According to one or more embodiments, a cluster
tool includes at least a first chamber and a central transfer
chamber. The central transfer chamber may house a robot that can
shuttle substrates between and among processing chambers and load
lock chambers. The transfer chamber is typically maintained at a
vacuum condition and provides an intermediate stage for shuttling
substrates from one chamber to another and/or to a load lock
chamber positioned at a front end of the cluster tool. Two
well-known cluster tools which may be adapted for the present
invention are the Centura.RTM. and the Endura.RTM., both available
from Applied Materials, Inc., of Santa Clara, Calif. The details of
one such staged-vacuum substrate processing apparatus is disclosed
in U.S. Pat. No. 5,186,718, entitled "Staged-Vacuum Wafer
Processing Apparatus and Method," Tepman et al., issued on Feb. 16,
1993. However, the exact arrangement and combination of chambers
may be altered for purposes of performing specific steps of a
process as described herein. Other processing chambers which may be
used include, but are not limited to, cyclical layer deposition
(CLD), atomic layer deposition (ALD), chemical vapor deposition
(CVD), physical vapor deposition (PVD), etch, pre-clean, chemical
clean, thermal treatment such as RTP, plasma nitridation, degas,
orientation, hydroxylation and other substrate processes. By
carrying out processes in a chamber on a cluster tool, surface
contamination of the substrate with atmospheric impurities can be
avoided without oxidation prior to depositing a subsequent
film.
According to one or more embodiments, the substrate is continuously
under vacuum or "load lock" conditions, and is not exposed to
ambient air when being moved from one chamber to the next. The
transfer chambers are thus under vacuum and are "pumped down" under
vacuum pressure. Inert gases may be present in the processing
chambers or the transfer chambers. In some embodiments, an inert
gas is used as a purge gas to remove some or all of the reactants
after forming the silicon layer on the surface of the substrate.
According to one or more embodiments, a purge gas is injected at
the exit of the deposition chamber to prevent reactants from moving
from the deposition chamber to the transfer chamber and/or
additional processing chamber. Thus, the flow of inert gas forms a
curtain at the exit of the chamber.
A substrate can be processed in single substrate deposition
chambers using, for example, the gas distribution apparatus
described. In such chambers, a single substrate is loaded,
processed and unloaded before another substrate is processed. A
substrate can also be processed in a continuous manner, like a
conveyer system, in which multiple substrate are individually
loaded into a first part of the chamber, move through the chamber
and are unloaded from a second part of the chamber. The shape of
the chamber and associated conveyer system can form a straight path
or curved path. Additionally, the processing chamber may be a
carousel in which multiple substrates are moved about a central
axis and are exposed to deposition, etch, annealing, cleaning, etc.
processes throughout the carousel path.
During processing, the substrate can be heated or cooled. Such
heating or cooling can be accomplished by any suitable means
including, but not limited to, changing the temperature of the
substrate support and flowing heated or cooled gases to the
substrate surface. In some embodiments, the substrate support
includes a heater/cooler which can be controlled to change the
substrate temperature conductively. In one or more embodiments, the
gases (either reactive gases or inert gases) being employed are
heated or cooled to locally change the substrate temperature. In
some embodiments, a heater/cooler is positioned within the chamber
adjacent the substrate surface to convectively change the substrate
temperature.
The substrate can also be stationary or rotated during processing.
A rotating substrate can be rotated continuously or in discreet
steps. For example, a substrate may be rotated throughout the
entire process, or the substrate can be rotated by a small amount
between exposure to different reactive or purge gases. Rotating the
substrate during processing (either continuously or in steps) may
help produce a more uniform deposition or etch by minimizing the
effect of, for example, local variability in gas flow
geometries.
Although the invention herein has been described with reference to
particular embodiments, it is to be understood that these
embodiments are merely illustrative of the principles and
applications of the present invention. It will be apparent to those
skilled in the art that various modifications and variations can be
made to the method and apparatus of the present invention without
departing from the spirit and scope of the invention. Thus, it is
intended that the present invention include modifications and
variations that are within the scope of the appended claims and
their equivalents.
* * * * *