U.S. patent application number 13/184562 was filed with the patent office on 2012-01-26 for plasma processing apparatus and liner assembly for tuning electrical skews.
This patent application is currently assigned to APPLIED MATERIALS, INC.. Invention is credited to James D. Carducci, Zhigang Chen, Kenneth S. Collins, Shahid Rauf.
Application Number | 20120018402 13/184562 |
Document ID | / |
Family ID | 45492720 |
Filed Date | 2012-01-26 |
United States Patent
Application |
20120018402 |
Kind Code |
A1 |
Carducci; James D. ; et
al. |
January 26, 2012 |
PLASMA PROCESSING APPARATUS AND LINER ASSEMBLY FOR TUNING
ELECTRICAL SKEWS
Abstract
The invention discloses a plasma processing apparatus comprising
a chamber lid, a chamber body and a support assembly. The chamber
body, defining a processing volume for containing a plasma, for
supporting the chamber lid. The chamber body is comprised of a
chamber sidewall, a bottom wall and a liner assembly. The chamber
sidewall and the bottom wall define a processing volume for
containing a plasma. The liner assembly, disposed inside the
processing volume, comprises of two or more slots formed thereon
for providing an axial symmetric RF current path. The support
assembly supports a substrate for processing within the chamber
body. With the liner assembly with several symmetric slots, the
present invention can prevent electromagnetic fields thereof from
being azimuthal asymmetry.
Inventors: |
Carducci; James D.;
(Sunnyvale, CA) ; Chen; Zhigang; (Campbell,
CA) ; Rauf; Shahid; (Pleasanton, CA) ;
Collins; Kenneth S.; (San Jose, CA) |
Assignee: |
APPLIED MATERIALS, INC.
Santa Clara
CA
|
Family ID: |
45492720 |
Appl. No.: |
13/184562 |
Filed: |
July 17, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61366462 |
Jul 21, 2010 |
|
|
|
Current U.S.
Class: |
216/67 ;
118/723I; 156/345.48; 427/523; 427/569; 428/34.1 |
Current CPC
Class: |
H01J 37/32623 20130101;
H01J 37/32082 20130101; H01L 21/67069 20130101; Y10T 428/13
20150115; H01J 37/32495 20130101; H01J 37/32458 20130101 |
Class at
Publication: |
216/67 ;
156/345.48; 427/569; 427/523; 118/723.I; 428/34.1 |
International
Class: |
C23F 1/00 20060101
C23F001/00; B32B 3/24 20060101 B32B003/24; C23C 14/48 20060101
C23C014/48; B32B 1/08 20060101 B32B001/08; C23F 1/08 20060101
C23F001/08; H05H 1/24 20060101 H05H001/24 |
Claims
1. A liner assembly, for use in a plasma processing apparatus,
comprising: a cylindrical body having an outer wall dimensioned to
slip inside of a sidewall of the plasma processing apparatus,
comprising the body having a plurality of slots formed therethrough
and arranged in a polar array, wherein at least one of the slots is
configured to allow a substrate to pass through the liner.
2. The liner assembly of claim 1, wherein the plurality of slots
have the same size.
3. The liner assembly of claim 1, wherein the plurality of slots
are spaced equidistantly apart.
4. The liner assembly of claim 1, wherein the plurality of slots
are four slots spaced 90 degrees apart.
5. The liner assembly of claim 1, wherein the cylindrical body
further comprises: a bottom coupled to the outer wall; and an inner
wall coupled to the bottom and dimensioned to slip over a substrate
support of the processing apparatus.
6. The liner assembly of claim 1, wherein the cylindrical body
further comprises: a coolant passage formed therein.
7. A plasma processing apparatus, comprising: a chamber body having
a sidewall and bottom wall, wherein the chamber sidewall and the
bottom wall define a processing volume for containing a plasma, the
sidewall having a slit valve tunnel formed therethrough; a lid
assembly disposed on the chamber body; and a liner assembly
disposed inside the processing volume and comprising a plurality of
slots, the plurality of slots comprising a first slot aligned with
the slit valve tunnel and at least a second slot, the first and
second slots arranged to produce an axial symmetric RF return
current path through the liner assembly.
8. The plasma processing apparatus of claim 7, wherein first and
second slots have the same size.
9. The plasma processing apparatus of claim 8, wherein the
plurality of slots are spaced equidistantly apart.
10. The plasma processing apparatus of claim 8, wherein the
plurality of slots further comprises: a third slot formed through
the liner assembly, wherein the first, second and third slots are
spaced 120 degrees apart.
11. The plasma processing apparatus of claim 8, wherein the
plurality of slots further comprises: a third slot formed through
the liner assembly; and a fourth slot formed through the liner
assembly, wherein the first, second, third and fourth slots are
spaced 90 degrees apart.
12. The plasma processing apparatus of claim 7, wherein the liner
assembly further comprises: an outer wall dimensioned to slip
inside of the sidewall of the chamber body; and a bottom coupled to
the outer wall.
13. The plasma processing apparatus of claim 12, wherein the liner
assembly further comprises: an inner wall coupled to the bottom and
dimensioned to slip over the substrate support.
14. The plasma processing apparatus of claim 7, wherein the liner
assembly further comprises: a coolant passage formed therein.
15. A method for plasma processing a substrate, comprising:
transferring a substrate into a plasma processing apparatus having
a liner assembly lining a chamber body, the liner assembly having
two or more slots formed therethrough, the slots selected to
provide a symmetrical distribution of RF current flow through the
liner assembly during processing; introducing process gases into
the chamber body from a gas source; coupling power to an electrode
to excite the process gases within the chamber body into a plasma;
and processing the substrate in the presence of the plasma.
16. The method of claim 15, wherein processing the substrate in the
presence of the plasma comprises: performing at least one of an
plasma etch process, a plasma enhanced chemical vapor deposition
process, a physical vapor deposition process, a plasma treatment
process, or an ion implantation process.
17. The method of claim 15, wherein coupling power to the electrode
to excite the process gases within the chamber body into the plasma
further comprises: providing RF power to at least one of a
showerhead or substrate support.
18. The method of claim 15, wherein two or more slots formed
through the liner assembly further comprises: a plurality of slots
having a same size and are arranged in a polar array about a
centerline of the liner assembly, wherein one of the slots is
aligned with a slit valve tunnel formed through the chamber
body.
19. The method of claim 15 further comprising: flowing a coolant
through a passage formed in the liner assembly.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit of U.S. Provisional Patent
Application Ser. No. 61/366,462, filed Jul. 21, 2010, which is
incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to a plasma
processing apparatus for fabricating electronic substrates in which
plasma is excited by RF power applied between electrodes. More
specifically, the present invention relates to a liner assembly
disposed inside the plasma processing apparatus for balancing RF
current flow launched from the electrodes.
[0004] 2. Description of the Prior Art
[0005] Electronic devices, such as flat panel displays and
integrated circuits, commonly are fabricated by a series of process
steps in which layers are deposited on a substrate and the
deposited material is etched into desired patterns. The process
steps commonly include physical vapor deposition (PVD), chemical
vapor deposition (CVD), plasma enhanced CVD (PECVD) and plasma
process. Specifically, the plasma process requires supplying a
process gas mixture to a vacuum chamber called a chamber body, and
then applying electrical or electromagnetic power (RF power) to
excite the process gas to a plasma state. In other words, the
process gas is excited into the plasma by the RF current launched
from electrodes. The plasma decomposes the gas mixture into ion
species that perform the desired deposition or etch process.
[0006] Generally, the substrate can be delivered from the transfer
chamber to the chamber body via transfer mechanisms (e.g. robot
blade) and be placed on a support assembly (e.g. susceptor or
pedestal) of each chamber body for processing. Furthermore, the
chamber body may also comprise a chamber liner to protect the inner
walls of the chamber body. Please refer to FIG. 1A. FIG. 1A
illustrates a perspective view of the traditional chamber liner. As
shown in FIG. 1A, to receive the substrate delivered from the
transfer chamber, the chamber liner 90, disposed inside a chamber
body, usually has a corresponding slot 902 for receiving the
substrate which is aligned with the slit valve tunnel of the
chamber body.
[0007] During substrate processing, RF currently launched from the
electrodes returns to the power source on the surface of the
chamber liner. Since the RF return current does not travel across
the gap defined by the slot 902, the RF return current travels
"around" the slot 902. This causes an area of RF current
concentration at the lateral edges of the slot 902, and an area of
low RF current to the top and bottom of the slot, thereby causing
an azimuthal asymmetric perturbation in RF current flow, as
illustrated in FIG. 1B.
[0008] FIG. 1B illustrates a schematic view of the traditional
chamber liner 90 from line A-A to line B-B for indicating
asymmetric RF current flow according to FIG. 1A. As shown in FIG.
1B, RF current flow (shown by dotted lines I.sub.90) is perturbed
by the slot 902, that is, the slot 902 creates area of high
concentration I.sub.92 which can lead to an azimuthal asymmetry in
the electromagnetic fields and ultimately the plasma causing a
non-uniform etch rate relative to the slot 902.
[0009] The electrical skews could hardly be prevented in the plasma
process because the traditional chamber liner failed to provide a
balanced RF current flow and led to the defective plasma process.
It is important that the RF current distribution within the chamber
be symmetric, such that the electromagnetic fields for the plasma
to provide the uniform azimuthal etch or deposition rate.
Therefore, a need exists for balancing RF current flow along the
chamber liner that prevents the above-mentioned problems.
SUMMARY OF THE INVENTION
[0010] Embodiments of the invention provide a liner assembly
configured to balancing RF current flowing thereon. According to
one embodiment of the invention, a liner is provided that comprises
two or more slots to provide an axial symmetric RF current path,
wherein one slot is a substrate access port.
[0011] In another embodiment of the invention, a plasma processing
apparatus is provided that includes a liner for balancing RF
current flow within the apparatus.
[0012] In one embodiment of the invention, the plasma processing
apparatus includes a chamber body having a liner disposed therein.
The line includes two or more slots formed therethrough for
providing an axial symmetric RF current path.
[0013] The additional embodiments of the present invention will no
doubt become understood to those of ordinary skill in the art after
reading the following detailed description, which is illustrated in
following figures and drawings.
BRIEF DESCRIPTION OF THE APPENDED DRAWINGS
[0014] The teachings of the present invention can be readily
understood by considering the following detailed description in
conjunction with the accompanying drawings, in which:
[0015] FIG. 1A illustrates a perspective view of the conventional
chamber liner.
[0016] FIG. 1B illustrates a projection of the conventional chamber
liner of FIG. 1A taken along section line A-A to line B-B for
indicating asymmetric RF current distribution of the surface of the
liner.
[0017] FIG. 2 illustrates a schematic view of a plasma processing
apparatus according to one embodiment of the invention.
[0018] FIG. 3A illustrates a perspective view of the chamber liner
according to one embodiment of the invention.
[0019] FIG. 3B illustrates a projection of the chamber liner from
line C-C to line D-D for indicating substantially symmetric RF
current flow according to FIG. 3A.
[0020] FIG. 4 is a flow chart illustrating one embodiment of a
plasma process according to one embodiment.
[0021] To facilitate understanding, identical reference numerals
have been used, where possible, to designate identical elements
that are common to the figures. It is contemplated that elements
disclosed in one embodiment may be beneficially utilized on other
embodiments without specific recitation.
DETAILED DESCRIPTION
[0022] FIG. 2 illustrates a schematic view of a plasma processing
apparatus according to one embodiment of the invention. The plasma
processing apparatus may be a plasma etch chamber, a plasma
enhanced chemical vapor deposition chamber, a physical vapor
deposition chamber, a plasma treatment chamber, an ion implantation
chamber or other suitable vacuum processing chamber. As shown in
FIG. 2, the plasma processing apparatus 1 comprises a chamber lid
10, a chamber body 12 and a substrate support assembly 14. The
chamber body 12 supports the chamber lid 10 to enclose a processing
region. The substrate support assembly 14 is disposed in the
chamber body 12 below the lid 10. All components of the plasma
processing apparatus 1 are described below respectively.
[0023] In one embodiment, the chamber lid 10 includes a showerhead
assembly 102, a lid plate 104, an insulator 106 and a spacer 108.
The lid plate 104 is generally seated on the chamber body 12 and is
typically coupled thereto by a hinge (not shown) to allow the
chamber lid 10 to be opened, exposing the interior of the chamber
body 12. The showerhead assembly 102 is typically comprised of a
conductive material and coupled to a RF power source 42 to serve as
an electrode for driving a plasma 16 formed within the chamber body
12. In other embodiments, an RF power source 44 may be coupled to
the substrate support assembly 14, such that the support serves as
the electrode. The chamber lid 10 is generally connected to a gas
source 40 for introducing a process gas into the processing volume.
Specifically, the lid plate 104 may comprise of an injection port
104a for receiving the process gases from the gas source 40, the
gases then flowing into the interior of the chamber body 12 through
the showerhead assembly 102. The showerhead assembly 102
facilitates uniform process gas delivery to a substrate 2 disposed
on the substrate support assembly 14.
[0024] The showerhead assembly 102 is electrically isolated from
the chamber lid 10 by the insulator 106. The insulator 106 may
comprise an inner ledge (not shown) for supporting the showerhead
assembly 102. The spacers 108 are RF conductive and disposed
between the chamber body 12 and the lid plate 104 and provide part
of an RF return path, as further discussed below.
[0025] The chamber body 12 comprises a chamber sidewall 122 and a
bottom wall 124. The chamber sidewall 122 and bottom wall 124 may
be fabricated from a unitary block of aluminum. The chamber
sidewall 122 and the bottom wall 124 of the chamber body 12 define
a processing volume for confining the plasma 16. The processing
volume is typically accessed through a slit valve tunnel 1222 in
the chamber sidewall 122 that facilitates movement of a substrate 2
into and out of the chamber body 12. In practice, a slit valve
tunnel 1222 is formed on the chamber sidewall 122 for allowing
entry and egress of the substrate 2 to/from the chamber body
12.
[0026] A liner assembly 3 is disposed inside the processing volume.
In one embodiment, the liner assembly 3 includes a chamber liner 30
and a bottom liner 32. The liner assembly 3 is removable to allow
periodic cleaning and maintenance. The liner assembly 3 may also
include a passage 202 for flowing a coolant therethrough so that
the temperature of the liner may be regulated. The chamber liner 30
includes two or more slots 34 and is generally
cylindrically-shaped, but may alternatively take the shape of the
interior wall of chambers having other geometries. At least one of
the slots 34 is suitable for passage of the substrate 2, and is
aligned with the slit valve tunnel 1222. In one embodiment, the
slots 34 have an elongated horizontal orientation. The bottom liner
32, engaged to the chamber liner 30, comprises a bowl portion and
an optional innermost cylindrically portion, wherein the chamber
sidewall 122 and the bottom wall 124 are shielded from the plasma
16 by the chamber liner 30 and the bottom liner 32. In practice,
the liner assembly 3 is disposed about the substrate support
assembly 14 and circumscribes the interior, vertical surfaces of
the chamber body 12. The liner assembly 3 may further comprise an
outer ledge (not shown) for being detachably fixed the liner
assembly 3 to the chamber sidewall 122. The liner assembly 3 may be
constructed of any process compatible material, such as aluminum or
yttria.
[0027] The slots 34 are formed symmetrically through the chamber
liner 30 for providing an axial symmetric RF current path. As
discussed above, one of the slots 34 is aligned with the slit valve
tunnel 1222, while the other slots 34 are distributed around the
chamber liner 30 in a position that compensates for changes RF
current density and/or distribution present on the liner 30 due to
the apertures of the slot 34 aligned with the slit valve tunnel
1222. In one embodiment, the slots 34 are arranged in a polar
array, and may be spaced apart equidistantly in a substantially
horizontal orientation (i.e., in an orientation perpendicular to a
center axis of the liner assembly 3.
[0028] The substrate support assembly 14 supports the substrate 2
during the processes within the chamber body 12. In practice, the
substrate support assembly 14 may include at least one embedded
heating element (not shown). Moreover, the substrate 2 can be, but
not limited to, a flat panel display, round wafer, liquid crystal
display, glass panel substrate, plastic substrate, and the like.
The substrate support assembly 14 may also be electrically
connected to a RF power source 44 to provide the substrate 2 bias
as desired for particular processes. In this embodiment, the
showerhead assembly 102 (first electrode) and the substrate support
assembly 14 (second electrode) can apply an RF power across
processing volume for exciting the process gases into the plasma
16.
[0029] According to one embodiment of the invention, the
symmetrically slotted chamber liner 30 can be further shown in FIG.
3A. FIG. 3A illustrates a perspective view of the chamber liner
according to one embodiment of the invention. As shown in FIG. 3A,
the chamber liner 30 has a plurality of symmetrically formed slots
34, wherein one of the slots 34 sized for transferring substrates.
The other slots 34, for example, are designed for tuning the
electrical skews in the plasma process, for example, to compensate
of the RF current density concentrations at the edges of the slot
34 utilized for substrate transfer through the liner. It should be
noticed that the slots shall be spaced symmetrically (i.e., in a
polar array about the centerline of the liner 30) to provide an
axial and azimuthally symmetric RF current return path for the RF
current launched from the electrode(s) and returning to the power
source through chamber liner 30.
[0030] In one embodiment, the plurality of slots 34 of the have the
same size. In another embodiment, the plurality of slots 34 are two
slots spaced 180 degrees apart. In another embodiment, the
plurality of slots 34 are three slots spaced 120 degrees apart. In
another embodiment, the plurality of slots 34 are four slots spaced
90 degrees apart.
[0031] FIG. 3B illustrates a schematic projection of the chamber
liner 30 taken from line C-C to line D-D, illustrating symmetric RF
current flow across the liner 30. As shown in FIG. 3B, the slots 34
are of equal size and symmetrically formed through the chamber
liner 30 such that the paths of RF current flow (shown by dotted
lines I.sub.30) are symmetrically perturbed by the slots 34. This
causes symmetric areas of increase current density I.sub.32 to be
uniformly distributed around the chamber liner 30. It should be
noticed that the slots 34 do not need to be disposed on the chamber
liner 30 at the same vertical level as long as the pattern of slots
34 are symmetric. Designers can create a desired path of the RF
current flow I.sub.30 by changing the pattern/location of the slots
34. In practice, the symmetry of RF current flow I.sub.30 can
enhance azimuthal symmetry of the electromagnetic fields, and
thereby enhance the uniformity of plasma processing results. It is
also contemplated that the position of the slots 34 may be located
to create an asymmetry of RF return current flow through the liner
assembly 3 to tune out another electrical or conductance asymmetry
within the processing apparatus 1 such that the resultant effect is
a more uniformly distributed plasma within the processing chamber,
thereby substantially eliminating azimuthal plasma skews.
[0032] To clearly describe the features and spirits of the
invention, a flow diagram is provided in FIG. 4 for illustrating
one embodiment of a plasma process 400 performed in accordance to
one embodiment of the invention. The process 400 begins at S50 by
transferring a substrate into a plasma processing apparatus 1
having a liner assembly 3 with two or more slots 34 formed
therethrough, the slots 34 selected to provide a symmetrical
distribution of RF current flow through the liner assembly 3 during
processing. At S52, process gases are introduced into the chamber
body 12 from the gas source 40. At S54, power is provided to the
electrode (i.e., from one or both of the showerhead assembly 102 or
substrate support assembly 14) to excite the process gases within
the processing apparatus 1 into the plasma 16. At S56, the
substrate is processed in the presence of the plasma. While the
power is applied to the electrode during processing, RF current
flows symmetrically through the liner assembly 3 to return to the
power source as discussed above. The symmetrical RF current flow
through the liner assembly 3 enhances azimuthal uniformity of the
plasma within the chamber, thereby enhancing processing results.
Plasma processing the substrate may include, but is not limited to,
performing an plasma etch process, a plasma enhanced chemical vapor
deposition process, a physical vapor deposition process, a plasma
treatment process, an ion implantation process or other plasma
assisted semiconductor process.
[0033] In summary, the present invention provides the liner
assembly with symmetric slots for balancing RF current flow coupled
to the liner assembly. Furthermore, the slots can also be formed in
certain patterns for creating desired path of the RF current flow
to tune the azimuthal plasma skews.
[0034] With the example and explanations above, the features and
spirits of the embodiments of the invention are described. Those
skilled in the art will readily observe that numerous modifications
and alterations of the device may be made while retaining the
teaching of the invention. Accordingly, the above disclosure should
be construed as limited only by the metes and bounds of the
appended claims.
* * * * *