U.S. patent application number 17/516065 was filed with the patent office on 2022-02-24 for generation of hydrogen reactive species for processing of workpieces.
The applicant listed for this patent is Beijing E-Town Semiconductor Technology Co., Ltd., Mattson Technology, Inc.. Invention is credited to Hua Chung, Xinliang Lu, Michael X. Yang, Qi Zhang.
Application Number | 20220059321 17/516065 |
Document ID | / |
Family ID | 1000005943351 |
Filed Date | 2022-02-24 |
United States Patent
Application |
20220059321 |
Kind Code |
A1 |
Zhang; Qi ; et al. |
February 24, 2022 |
Generation of Hydrogen Reactive Species For Processing of
Workpieces
Abstract
Methods, systems, and apparatus for generating hydrogen radicals
for processing a workpiece, such as a semiconductor workpiece, are
provided. In one example implementation, a method can include
generating one or more species in a plasma chamber from an inert
gas by inducing a plasma in the inert gas using a plasma source;
mixing hydrogen gas with the one or more species to generate one or
more hydrogen radicals; and exposing the workpiece in a processing
chamber to the one or more hydrogen radicals.
Inventors: |
Zhang; Qi; (San Jose,
CA) ; Lu; Xinliang; (Fremont, CA) ; Chung;
Hua; (Saratoga, CA) ; Yang; Michael X.; (Palo
Alto, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Mattson Technology, Inc.
Beijing E-Town Semiconductor Technology Co., Ltd. |
Fremont
Beijing |
CA |
US
CN |
|
|
Family ID: |
1000005943351 |
Appl. No.: |
17/516065 |
Filed: |
November 1, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
16420542 |
May 23, 2019 |
11164725 |
|
|
17516065 |
|
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|
62683246 |
Jun 11, 2018 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 21/67028 20130101;
H01J 37/32357 20130101; H01J 37/32422 20130101; B08B 7/00 20130101;
H01J 37/3244 20130101; H01J 2237/006 20130101; H01L 21/02057
20130101; H01J 37/321 20130101; C01B 3/02 20130101; H01J 2237/335
20130101 |
International
Class: |
H01J 37/32 20060101
H01J037/32; H01L 21/67 20060101 H01L021/67; H01L 21/02 20060101
H01L021/02; B08B 7/00 20060101 B08B007/00; C01B 3/02 20060101
C01B003/02 |
Claims
1-18. (canceled)
19. A method for processing a workpiece, the method comprising:
generating one or more species in an inert gas in a first chamber;
filtering one or more ions in the first chamber using a separation
grid to generate a filtered mixture; injecting a hydrogen gas
downstream of the first chamber into the filtered mixture to
generate one or more hydrogen radicals; exposing the workpiece to
the one or more hydrogen radicals in a second chamber, the second
chamber being separated from the first chamber by the separation
grid.
20. (canceled)
21. The method of claim 19, wherein injecting a hydrogen gas
downstream of the first chamber into the filtered mixture to
generate one or more hydrogen radicals comprises mixing hydrogen
gas with neutral species passing through the separation grid.
22. The method of claim 19, wherein injecting a hydrogen gas
downstream of the first chamber into the filtered mixture to
generate one or more hydrogen radicals comprises mixing hydrogen
gas with neutral species in the separation grid.
23. The method of claim 19, wherein the inert gas comprises
helium.
24. The method of claim 19, wherein the plasma is generated using
an inductively coupled plasma source.
25. The method of claim 19, wherein exposing the workpiece in the
second chamber to the one or more hydrogen radicals at least
partially removes a photoresist layer on the workpiece.
26. The method of claim 19, wherein exposing the workpiece in a
processing chamber to the one or more hydrogen radicals at least
partially removes a residual organic material on the workpiece.
27. The method of claim 19, further comprising heating the
workpiece to a temperature greater than about 400.degree. C.,
wherein exposing the workpiece in the processing chamber to the one
or more hydrogen radicals modifies silicon atom mobility.
28. The method of claim 19, wherein exposing the workpiece in a
second chamber to the one or more hydrogen radicals at least
partially removes a damaged silicon layer.
29. The method of claim 19, wherein exposing the workpiece in the
processing chamber to the one or more hydrogen radicals at least
partially removes a suboxide layer.
30. The method of claim 19, further comprising mixing the one or
more hydrogen radicals with a metal-containing gas to deposit a
metal on the workpiece.
31. The method of claim 30, wherein the metal-containing gas
comprises titanium.
32. The method of claim 30, wherein the metal-containing gas
comprises tantalum.
33. The method of claim 30, wherein the metal-containing gas
comprises aluminum.
Description
PRIORITY CLAM
[0001] The present application claims the benefit of priority of
U.S. Provisional Application Ser. No. 62/683,246 titled "Generation
of Hydrogen Reactive Species for Processing of Workpieces," filed
on Jun. 11, 2018, which is incorporated herein by reference for all
purposes.
FIELD
[0002] The present disclosure relates generally to generation of
hydrogen reactive species for processing of workpieces using, for
instance, a plasma processing apparatus.
BACKGROUND
[0003] In semiconductor processing, device dimension and materials
thickness continue to decrease with shrinking critical dimension in
semiconductor devices. In advanced device nodes, materials surface
properties and interface integrity become increasingly important to
device performance.
SUMMARY
[0004] Aspects and advantages of embodiments of the present
disclosure will be set forth in part in the following description,
or may be learned from the description, or may be learned through
practice of the embodiments.
[0005] One example aspect of the present disclosure is directed to
a method for processing a workpiece. The method can include
generating one or more species in a plasma chamber from an inert
gas by inducing a plasma in the inert gas using a plasma source.
The method can include mixing hydrogen gas with the one or more
species to generate one or more hydrogen radicals. The method can
include exposing the workpiece in a processing chamber to the one
or more hydrogen radicals.
[0006] These and other features, aspects and advantages of various
embodiments will become better understood with reference to the
following description and appended claims. The accompanying
drawings, which are incorporated in and constitute a part of this
specification, illustrate embodiments of the present disclosure
and, together with the description, serve to explain the related
principles.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Detailed discussion of embodiments directed to one of
ordinary skill in the art are set forth in the specification, which
makes reference to the appended figures, in which:
[0008] FIG. 1 depicts an example plasma processing apparatus
according to example embodiments of the present disclosure;
[0009] FIG. 2 depicts a flow diagram of an example method according
to example embodiments of the present disclosure;
[0010] FIG. 3 depicts example mixing of a hydrogen gas with one or
more species generated from an inert gas according to example
embodiments of the present disclosure;
[0011] FIG. 4 depicts example mixing of a hydrogen gas with one or
more species generated from an inert gas according to example
embodiments of the present disclosure;
[0012] FIG. 5 depicts an example plasma processing apparatus
according to example embodiments of the present disclosure; and
[0013] FIG. 6 depicts an example plasma processing apparatus
according to example embodiments of the present disclosure.
DETAILED DESCRIPTION
[0014] Reference now will be made in detail to embodiments, one or
more examples of which are illustrated in the drawings. Each
example is provided by way of explanation of the embodiments, not
limitation of the present disclosure. In fact, it will be apparent
to those skilled in the art that various modifications and
variations can be made to the embodiments without departing from
the scope or spirit of the present disclosure. For instance,
features illustrated or described as part of one embodiment can be
used with another embodiment to yield a still further embodiment.
Thus, it is intended that aspects of the present disclosure cover
such modifications and variations.
[0015] Example aspects of the present disclosure are directed to
generation of hydrogen radicals for processing of a workpiece, such
as a semiconductor workpiece. Hydrogen radicals have various
applications in semiconductor processing. For instance, at low
temperature, hydrogen radicals can remove photoresist or other
polymer materials effectively with reduced underlying materials
damage and/or oxidation. At high temperature, hydrogen radicals can
selectively etch damaged silicon materials (e.g. for silicon fin
trimming in three-dimensional FINFET structures).
[0016] Hydrogen radicals can be generated, for instance, by passing
a hydrogen gas through a hot wire (e.g., a tungsten hot wire).
Hydrogen radicals can be generated, for instance, using capacitive
and/or inductive plasma sources. For instance, hydrogen radicals
can be generated from a process gas using an inductively coupled
plasma source in a remote plasma chamber. Ion filtering can be
implemented, for instance, using a grounded separation grid to
reduce ions generated in the plasma and allow neutral hydrogen
radicals to pass through the grid. The grid can have a distribution
of holes to facilitate control of radical distribution. Energy of
the hydrogen radicals can be controlled, for instance, using pulsed
RF power applied to the power source and/or via post-plasma
modification (e.g., mixing of other gases).
[0017] According to example embodiments, an inert gas (e.g.,
helium, argon, xenon, neon, etc.) can be activated using a plasma
source in a plasma chamber to generate excited species from the
inert gas. A hydrogen gas can be mixed with the excited species
(e.g., outside of the plasma chamber, such as downstream of the
plasma chamber) to generate one or more hydrogen radicals. The
hydrogen radicals can be exposed to a workpiece (e.g., in a
processing chamber) to implement various semiconductor fabrication
processes.
[0018] In some embodiments, the method can include generating one
or more excited inert gas molecules (e.g., excited He molecules) in
a plasma chamber that is separated from a processing chamber by a
separation grid. The excited inert gas molecules can be generated,
for instance, by inducing a plasma in a process gas using a plasma
source (e.g., inductive plasma source, capacitive plasma source,
etc.). The process gas can be an inert gas. For instance, the
process gas can be helium, argon, xenon, neon, or other inert gas.
In some embodiments, the process gas can consist of an inert
gas.
[0019] The method can include filtering ions while allowing the
passage of neutral species to generate a filtered mixture with
neutral radicals for exposure to the workpiece. For instance, a
separation grid can be used to filter ions generated in the plasma
chamber and allow passage of neutral species through holes in the
separation grid to the processing chamber for exposure to the
workpiece.
[0020] In some embodiments, the hydrogen radicals can be generated
by mixing hydrogen gas (H.sub.2) with the excited species at or
below (e.g., downstream) of the separation grid. For instance, in
some embodiments, the separation grid can have a plurality of grid
plates. The hydrogen gas can be injected into species passing
through the separation grid at a location below or downstream of
one of the grid plates. In some embodiments, the hydrogen gas can
be injected into species passing through the separation grid at a
location between two grid plates. In some embodiments, the hydrogen
gas can be injected into the species at a location beneath all of
the grid plates (e.g., in the processing chamber).
[0021] Mixing the hydrogen gas with the excited species from the
inert gas can result in the generation of one or more hydrogen
radicals, such as neutral hydrogen radicals. The hydrogen radicals
can be exposed to a workpiece in the processing chamber.
[0022] In some embodiments, the workpiece can be supported on a
pedestal or workpiece support. The pedestal or workpiece support
can include a temperature regulation system (e.g., one or more
electrical heaters) used to control a temperature of the workpiece
temperature during processing. In some embodiments, process can be
carried out with the workpiece at a temperature in the range of
about 20.degree. C. to about 500.degree. C.
[0023] The hydrogen radicals can be exposed to a workpiece in the
processing chamber for implementation of a variety of different
semiconductor fabrication processes. For example, the hydrogen
radicals can be used for removal of a photoresist layer on the
workpiece. As another example, the hydrogen radicals can be used to
remove a residual (e.g., residual organic) on the workpiece to
clean the workpiece. As another example, the hydrogen radicals can
be used to assist with silicon atom mobility and smoothing of the
workpiece surface (e.g., at high temperatures such as temperatures
greater than about 400.degree. C.). As another example, the
hydrogen radicals can be used to at least partially remove a
damaged silicon layer on the workpiece. As yet another example, the
hydrogen radicals can be used to remove a suboxide layer on the
workpiece. The hydrogen radicals can be used to implement other
semiconductor process applications without deviating from the scope
of the present disclosure.
[0024] In some embodiments, a metal-containing gas can be mixed
with the one or more hydrogen radicals to facilitate deposition of
a thin metal film on the workpiece. In some embodiments, the metal
can be titanium. In some embodiments, the metal can be tantalum. In
some embodiments, the metal can be aluminum.
[0025] Aspects of the present disclosure are discussed with
reference to a "wafer" or semiconductor wafer for purposes of
illustration and discussion. Those of ordinary skill in the art,
using the disclosures provided herein, will understand that the
example aspects of the present disclosure can be used in
association with any semiconductor substrate or other suitable
substrate. "Downstream" in reference to a plasma chamber refers to
a location in plasma processing apparatus that is exposed to
species generated in the plasma chamber, such as a location outside
the plasma chamber that is exposed to species generated in the
plasma chamber. In addition, the use of the term "about" in
conjunction with a numerical value is intended to refer to within
ten percent (10%) of the stated numerical value. A "pedestal"
refers to any structure that can be used to support a
workpiece.
[0026] FIG. 1 depicts an example plasma processing apparatus 100
that can be used to perform processes according to example
embodiments of the present disclosure. As illustrated, plasma
processing apparatus 100 includes a processing chamber 110 and a
plasma chamber 120 that is separated from the processing chamber
110. Processing chamber 110 includes a substrate holder or pedestal
112 operable to hold a workpiece 114 to be processed, such as a
semiconductor wafer. In this example illustration, a plasma is
generated in plasma chamber 120 (i.e., plasma generation region) by
an inductively coupled plasma source 135 and desired species are
channeled from the plasma chamber 120 to the surface of workpiece
114 through a separation grid assembly 200.
[0027] Aspects of the present disclosure are discussed with
reference to an inductively coupled plasma source for purposes of
illustration and discussion. Those of ordinary skill in the art,
using the disclosures provided herein, will understand that any
plasma source (e.g., inductively coupled plasma source,
capacitively coupled plasma source, etc.) can be used without
deviating from the scope of the present disclosure.
[0028] The plasma chamber 120 includes a dielectric side wall 122
and a ceiling 124. The dielectric side wall 122, ceiling 124, and
separation grid 200 define a plasma chamber interior 125.
Dielectric side wall 122 can be formed from a dielectric material,
such as quartz and/or alumina. The inductively coupled plasma
source 135 can include an induction coil 130 disposed adjacent the
dielectric side wall 122 about the plasma chamber 120. The
induction coil 130 is coupled to an RF power generator 134 through
a suitable matching network 132. Process gases (e.g., an inert gas)
can be provided to the chamber interior from gas supply 150 and
annular gas distribution channel 151 or other suitable gas
introduction mechanism. When the induction coil 130 is energized
with RF power from the RF power generator 134, a plasma can be
generated in the plasma chamber 120. In a particular embodiment,
the plasma processing apparatus 100 can include an optional
grounded Faraday shield 128 to reduce capacitive coupling of the
induction coil 130 to the plasma.
[0029] As shown in FIG. 1, a separation grid 200 separates the
plasma chamber 120 from the processing chamber 110. The separation
grid 200 can be used to perform ion filtering from a mixture
generated by plasma in the plasma chamber 120 to generate a
filtered mixture. The filtered mixture can be exposed to the
workpiece 114 in the processing chamber.
[0030] In some embodiments, the separation grid 200 can be a
multi-plate separation grid. For instance, the separation grid 200
can include a first grid plate 210 and a second grid plate 220 that
are spaced apart in parallel relationship to one another. The first
grid plate 210 and the second grid plate can be separated by a
distance.
[0031] The first grid plate 210 can have a first grid pattern
having a plurality of holes. The second grid plate 220 can have a
second grid pattern having a plurality of holes. The first grid
pattern can be the same as or different from the second grid
pattern. Charged particles can recombine on the walls in their path
through the holes of each grid plate 210, 220 in the separation
grid. Neutral species (e.g., radicals) can flow relatively freely
through the holes in the first grid plate 210 and the second grid
plate 220. The size of the holes and thickness of each grid plate
210 and 220 can affect transparency for both charged and neutral
particles.
[0032] In some embodiments, the first grid plate 210 can be made of
metal (e.g., aluminum) or other electrically conductive material
and/or the second grid plate 220 can be made from either an
electrically conductive material or dielectric material (e.g.,
quartz, ceramic, etc.). In some embodiments, the first grid plate
210 and/or the second grid plate 220 can be made of other
materials, such as silicon or silicon carbide. In the event a grid
plate is made of metal or other electrically conductive material,
the grid plate can be grounded.
[0033] FIG. 2 depicts a flow diagram of an example method (300)
according to example aspects of the present disclosure. The method
(300) can be implemented using the plasma processing apparatus 100.
However, as will be discussed in detail below, the methods
according to example aspects of the present disclosure can be
implemented using other approaches without deviating from the scope
of the present disclosure. FIG. 2 depicts steps performed in a
particular order for purposes of illustration and discussion. Those
of ordinary skill in the art, using the disclosures provided
herein, will understand that various steps of any of the methods
described herein can be omitted, expanded, performed
simultaneously, rearranged, and/or modified in various ways without
deviating from the scope of the present disclosure. In addition,
various additional steps (not illustrated) can be performed without
deviating from the scope of the present disclosure.
[0034] At (302), the method can include heating the workpiece. For
instance, the workpiece 114 can be heated in the processing chamber
to a process temperature. The workpiece 114 can be heated, for
instance, using one or more heating systems associated with the
pedestal 112. In some embodiments, the workpiece can be heated to a
process temperature in the range of about 20.degree. C. to about
500.degree. C., such as about 400.degree. C. or any other
temperature or range of temperatures therebetween.
[0035] At (304), the method can include admitting a process gas
(e.g., an inert gas) into the plasma chamber. For instance, a
process gas can be admitted into the plasma chamber interior 125
from a gas source 150 via annular gas distribution channel 151 or
other suitable gas introduction mechanism. The process gas can be
an inert gas, such as an inert gas with no reactive gas. For
instance, the process gas can consist of the inert gas. The process
gas can be, for instance, helium, argon, xenon, neon or other inert
gas.
[0036] At (306), the method can include energizing an inductively
coupled plasma source to generate a plasma in a plasma chamber. For
instance, induction coil 130 can be energized with RF energy from
RF power generator 134 to generate a plasma in the plasma chamber
interior 125. In some embodiments, the inductively coupled power
source can be energized with pulsed power to obtain species with
desired plasma energy. At (308), the plasma can be used to generate
one or more species (e.g., excited inert gas molecules) from the
process gas.
[0037] At (310), the method can include filtering one or more ions
generated by the plasma in the mixture to create a filtered
mixture. The filtered mixture can include species (e.g., excited
inert gas molecules, etc.) generated by the plasma in the process
gas. In some embodiments, the one or more ions can be filtered
using a separation grid assembly separating the plasma chamber from
a processing chamber where the workpiece is located. For instance,
separation grid 200 can be used to filter ions generated by the
plasma.
[0038] The separation grid 200 can have a plurality of holes.
Charged particles (e.g., ions) can recombine on the walls in their
path through the plurality of holes. Neutral particles (e.g.,
radicals) can pass through the holes. In some embodiments, the
separation grid 200 can be configured to filter ions with an
efficiency greater than or equal to about 90%, such as greater than
or equal to about 95%.
[0039] In some embodiments, the separation grid can be a
multi-plate separation grid. The multi-plate separation grid can
have multiple separation grid plates in parallel. The arrangement
and alignment of holes in the grid plate can be selected to provide
a desired efficiency for ion filtering, such as greater than or
equal to about 95%.
[0040] At (312), the method can include mixing hydrogen (e.g.,
H.sub.2 gas) with the species to generate one or more hydrogen
radicals. The hydrogen can be mixed with the species by injecting a
gas into post plasma mixtures (e.g., at or below a separation
grid).
[0041] FIG. 3 depicts an example separation grid 200 for injection
of hydrogen post plasma according to example embodiments of the
present disclosure. More particularly, the separation grid 200
includes a first grid plate 210 and a second grid plate 220
disposed in parallel relationship. The first grid plate 210 and the
second grid plate 220 can provide for ion/UV filtering.
[0042] The first grid plate 210 and a second grid plate 220 can be
in parallel relationship with one another. The first grid plate 210
can have a first grid pattern having a plurality of holes. The
second grid plate 220 can have a second grid pattern having a
plurality of holes. The first grid pattern can be the same as or
different from the second grid pattern. Species (e.g., excited
inert gas molecules) 215 from the plasma can be exposed to the
separation grid 200. Charged particles (e.g., ions) can recombine
on the walls in their path through the holes of each grid plate
210, 220 in the separation grid 200. Neutral species (e.g., excited
inert gas molecules) can flow relatively freely through the holes
in the first grid plate 210 and the second grid plate 220.
[0043] Subsequent to the second grid plate 220, a gas injection
source 230 can be configured to mix hydrogen 232 into the species
passing through the separation grid 200. A mixture 225 including
hydrogen radicals resulting from the injection of hydrogen gas can
pass through a third grid plate 235 for exposure to the workpiece
in the processing chamber.
[0044] The present example is discussed with reference to a
separation grid with three grid plates for example purposes. Those
of ordinary skill in the art, using the disclosures provided
herein, will understand that more or fewer grid plates can be used
without deviating from the scope of the present disclosure. In
addition, the hydrogen can be mixed with the species at any point
in the separation grid and/or after the separation grid in the
processing chamber. For instance, the gas injection source 230 can
be located between first grid plate 210 and second grid plate
220.
[0045] As shown in FIG. 4, in some embodiments, the grid assembly
200. For instance, the gas injection source 230 can inject hydrogen
gas into the species passing through the separation grid 200 at a
location in the processing chamber below a first grid plate 210 and
a second grid plate 220.
[0046] At (314) of FIG. 2, the method can include exposing the
workpiece to the hydrogen radicals. Exposing the workpiece to the
hydrogen radicals can be used to perform a variety of semiconductor
fabrication steps.
[0047] For example, the hydrogen radicals can be exposed to a
workpiece in the processing chamber for implementation of a variety
of different semiconductor fabrication processes. For example, the
hydrogen radicals can be used for removal of a photoresist layer on
the workpiece. As another example, the hydrogen radicals can be
used to remove a residual (e.g., residual organic) on the workpiece
to clean the workpiece. As another example, the hydrogen radicals
can be used to assist with silicon atom mobility and smoothing of
the workpiece surface (e.g., at high temperatures such as
temperatures greater than about 400.degree. C.). As another
example, the hydrogen radicals can be used to at least partially
remove a damaged silicon layer on the workpiece. As yet another
example, the hydrogen radicals can be used to remove a suboxide
layer on the workpiece. The hydrogen radicals can be used to
implement other semiconductor process applications without
deviating from the scope of the present disclosure.
[0048] In some embodiments, a metal-containing gas can be mixed
with the one or more hydrogen radicals to facilitate deposition of
a thin metal film on the workpiece. In some embodiments, the metal
can be titanium. In some embodiments, the metal can be tantalum. In
some embodiments, the metal can be aluminum.
[0049] FIG. 5 depicts an example plasma processing apparatus 400
that can be used to implement processes according to example
embodiments of the present disclosure. The plasma processing
apparatus 400 is similar to the plasma processing apparatus 100 of
FIG. 1.
[0050] More particularly, plasma processing apparatus 400 includes
a processing chamber 110 and a plasma chamber 120 that is separated
from the processing chamber 110. Processing chamber 110 includes a
substrate holder or pedestal 112 operable to hold a workpiece 114
to be processed, such as a semiconductor wafer. In this example
illustration, a plasma is generated in plasma chamber 120 (i.e.,
plasma generation region) by an inductively coupled plasma source
135 and desired species are channeled from the plasma chamber 120
to the surface of workpiece 114 through a separation grid assembly
200.
[0051] The plasma chamber 120 includes a dielectric side wall 122
and a ceiling 124. The dielectric side wall 122, ceiling 124, and
separation grid 200 define a plasma chamber interior 125.
Dielectric side wall 122 can be formed from a dielectric material,
such as quartz and/or alumina. The inductively coupled plasma
source 135 can include an induction coil 130 disposed adjacent the
dielectric side wall 122 about the plasma chamber 120. The
induction coil 130 is coupled to an RF power generator 134 through
a suitable matching network 132. Process gases (e.g., an inert gas)
can be provided to the chamber interior from gas supply 150 and
annular gas distribution channel 151 or other suitable gas
introduction mechanism. When the induction coil 130 is energized
with RF power from the RF power generator 134, a plasma can be
generated in the plasma chamber 120. In a particular embodiment,
the plasma processing apparatus 100 can include an optional
grounded Faraday shield 128 to reduce capacitive coupling of the
induction coil 130 to the plasma.
[0052] As shown in FIG. 5, a separation grid 200 separates the
plasma chamber 120 from the processing chamber 110. The separation
grid 200 can be used to perform ion filtering from a mixture
generated by plasma in the plasma chamber 120 to generate a
filtered mixture. The filtered mixture can be exposed to the
workpiece 114 in the processing chamber.
[0053] In some embodiments, the separation grid 200 can be a
multi-plate separation grid. For instance, the separation grid 200
can include a first grid plate 210 and a second grid plate 220 that
are spaced apart in parallel relationship to one another. The first
grid plate 210 and the second grid plate can be separated by a
distance.
[0054] The first grid plate 210 can have a first grid pattern
having a plurality of holes. The second grid plate 220 can have a
second grid pattern having a plurality of holes. The first grid
pattern can be the same as or different from the second grid
pattern. Charged particles can recombine on the walls in their path
through the holes of each grid plate 210, 220 in the separation
grid. Neutral species (e.g., radicals) can flow relatively freely
through the holes in the first grid plate 210 and the second grid
plate 220. The size of the holes and thickness of each grid plate
210 and 220 can affect transparency for both charged and neutral
particles.
[0055] In some embodiments, the first grid plate 210 can be made of
metal (e.g., aluminum) or other electrically conductive material
and/or the second grid plate 220 can be made from either an
electrically conductive material or dielectric material (e.g.,
quartz, ceramic, etc.). In some embodiments, the first grid plate
210 and/or the second grid plate 220 can be made of other
materials, such as silicon or silicon carbide. In the event a grid
plate is made of metal or other electrically conductive material,
the grid plate can be grounded.
[0056] As discussed above, a hydrogen gas can be injected into
species passing through the separation grid 200 to generate one or
more hydrogen radicals for exposure to the workpiece 114. The
hydrogen radicals can be used to implement a variety of
semiconductor fabrication processes.
[0057] The example plasma processing apparatus 400 of FIG. 5 is
operable to generate a first plasma 402 (e.g., a remote plasma) in
the plasma chamber 120 and a second plasma 404 (e.g., a direct
plasma) in the processing chamber 110. As used herein, a "remote
plasma" refers to a plasma generated remotely from a workpiece,
such as in a plasma chamber separated from a workpiece by a
separation grid. As used herein, a "direct plasma" refers to a
plasma that is directly exposed to a workpiece, such as a plasma
generated in a processing chamber having a pedestal operable to
support the workpiece.
[0058] More particularly, the plasma processing apparatus 400 of
FIG. 5 includes a bias source having bias electrode 410 in the
pedestal 112. The bias electrode 410 can be coupled to an RF power
generator 414 via a suitable matching network 412. When the bias
electrode 410 is energized with RF energy, a second plasma 404 can
be generated from a mixture in the processing chamber 110 for
direct exposure to the workpiece 114. The processing chamber 110
can include a gas exhaust port 416 for evacuating a gas from the
processing chamber 110.
[0059] FIG. 6 depicts a processing chamber 500 similar to that of
FIG. 1 and FIG. 5. More particularly, plasma processing apparatus
500 includes a processing chamber 110 and a plasma chamber 120 that
is separated from the processing chamber 110. Processing chamber
110 includes a substrate holder or pedestal 112 operable to hold a
workpiece 114 to be processed, such as a semiconductor wafer. In
this example illustration, a plasma is generated in plasma chamber
120 (i.e., plasma generation region) by an inductively coupled
plasma source 135 and desired species (e.g., excited inert gas
molecules) are channeled from the plasma chamber 120 to the surface
of workpiece 114 through a separation grid assembly 200.
[0060] The plasma chamber 120 includes a dielectric side wall 122
and a ceiling 124. The dielectric side wall 122, ceiling 124, and
separation grid 200 define a plasma chamber interior 125.
Dielectric side wall 122 can be formed from a dielectric material,
such as quartz and/or alumina. The inductively coupled plasma
source 135 can include an induction coil 130 disposed adjacent the
dielectric side wall 122 about the plasma chamber 120. The
induction coil 130 is coupled to an RF power generator 134 through
a suitable matching network 132. Process gas (e.g., an inert gas)
can be provided to the chamber interior from gas supply 150 and
annular gas distribution channel 151 or other suitable gas
introduction mechanism. When the induction coil 130 is energized
with RF power from the RF power generator 134, a plasma can be
generated in the plasma chamber 120. In a particular embodiment,
the plasma processing apparatus 100 can include an optional
grounded Faraday shield 128 to reduce capacitive coupling of the
induction coil 130 to the plasma.
[0061] As shown in FIG. 6, a separation grid 200 separates the
plasma chamber 120 from the processing chamber 110. The separation
grid 200 can be used to perform ion filtering from a mixture
generated by plasma in the plasma chamber 120 to generate a
filtered mixture. The filtered mixture can be exposed to the
workpiece 114 in the processing chamber.
[0062] In some embodiments, the separation grid 200 can be a
multi-plate separation grid. For instance, the separation grid 200
can include a first grid plate 210 and a second grid plate 220 that
are spaced apart in parallel relationship to one another. The first
grid plate 210 and the second grid plate can be separated by a
distance.
[0063] The first grid plate 210 can have a first grid pattern
having a plurality of holes. The second grid plate 220 can have a
second grid pattern having a plurality of holes. The first grid
pattern can be the same as or different from the second grid
pattern. Charged particles can recombine on the walls in their path
through the holes of each grid plate 210, 220 in the separation
grid. Neutral species (e.g., radicals) can flow relatively freely
through the holes in the first grid plate 210 and the second grid
plate 220. The size of the holes and thickness of each grid plate
210 and 220 can affect transparency for both charged and neutral
particles.
[0064] In some embodiments, the first grid plate 210 can be made of
metal (e.g., aluminum) or other electrically conductive material
and/or the second grid plate 220 can be made from either an
electrically conductive material or dielectric material (e.g.,
quartz, ceramic, etc.). In some embodiments, the first grid plate
210 and/or the second grid plate 220 can be made of other
materials, such as silicon or silicon carbide. In the event a grid
plate is made of metal or other electrically conductive material,
the grid plate can be grounded.
[0065] The example plasma processing apparatus 500 of FIG. 6 is
operable to generate a first plasma 402 (e.g., a remote plasma) in
the plasma chamber 120 and a second plasma 404 (e.g., a direct
plasma) in the processing chamber 110. As shown, the plasma
processing apparatus 500 can include an angled dielectric sidewall
522 that extends from the vertical side wall 122 associated with
the remote plasma chamber 120. The angled dielectric sidewall 522
can form a part of the processing chamber 110.
[0066] A second inductive plasma source 535 can be located
proximate the dielectric sidewall 522. The second inductive plasma
source 535 can include an induction coil 510 coupled to an RF
generator 514 via a suitable matching network 512. The induction
coil 510, when energized with RF energy, can induce a direct plasma
404 from a mixture in the processing chamber 110. A Faraday shield
528 can be disposed between the induction coil 510 and the sidewall
522.
[0067] The pedestal 112 can be movable in a vertical direction V.
For instance, the pedestal 112 can include a vertical lift 516 that
can be configured to adjust a distance between the pedestal 112 and
the separation grid assembly 200. As one example, the pedestal 112
can be located in a first vertical position for processing using
the remote plasma 402. The pedestal 112 can be in a second vertical
position for processing using the direct plasma 404. The first
vertical position can be closer to the separation grid assembly 200
relative to the second vertical position.
[0068] The plasma processing apparatus 500 of FIG. 6 includes a
bias source having bias electrode 410 in the pedestal 112. The bias
electrode 410 can be coupled to an RF power generator 414 via a
suitable matching network 412. The processing chamber 110 can
include a gas exhaust port 416 for evacuating a gas from the
processing chamber 110.
[0069] While the present subject matter has been described in
detail with respect to specific example embodiments thereof, it
will be appreciated that those skilled in the art, upon attaining
an understanding of the foregoing may readily produce alterations
to, variations of, and equivalents to such embodiments.
Accordingly, the scope of the present disclosure is by way of
example rather than by way of limitation, and the subject
disclosure does not preclude inclusion of such modifications,
variations and/or additions to the present subject matter as would
be readily apparent to one of ordinary skill in the art.
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