U.S. patent application number 12/780531 was filed with the patent office on 2011-11-17 for inductive plasma source with metallic shower head using b-field concentrator.
This patent application is currently assigned to APPLIED MATERIALS, INC.. Invention is credited to Canfeng Lai, Jose Antonio Marin, Peter I. Porshnev, Jeffrey Tobin.
Application Number | 20110278260 12/780531 |
Document ID | / |
Family ID | 44910845 |
Filed Date | 2011-11-17 |
United States Patent
Application |
20110278260 |
Kind Code |
A1 |
Lai; Canfeng ; et
al. |
November 17, 2011 |
INDUCTIVE PLASMA SOURCE WITH METALLIC SHOWER HEAD USING B-FIELD
CONCENTRATOR
Abstract
A method and apparatus for plasma processing of substrates is
provided. A processing chamber has a substrate support and a lid
assembly facing the substrate support. The lid assembly has a
plasma source that comprises an inductive coil disposed within a
conductive plate, which may comprise nested conductive rings. The
inductive coil is substantially coplanar with the conductive plate,
and insulated therefrom by an insulator that fits within a channel
formed in the conductive plate, or nests within the conductive
rings. A field concentrator is provided around the inductive coil,
and insulated therefrom by isolators. The plasma source is
supported from a conductive support plate. A gas distributor
supplies gas to the chamber through a central opening of the
support plate and plasma source from a conduit disposed through the
conductive plate.
Inventors: |
Lai; Canfeng; (Fremont,
CA) ; Tobin; Jeffrey; (Mountain View, CA) ;
Porshnev; Peter I.; (San Jose, CA) ; Marin; Jose
Antonio; (San Jose, CA) |
Assignee: |
APPLIED MATERIALS, INC.
Santa Clara
CA
|
Family ID: |
44910845 |
Appl. No.: |
12/780531 |
Filed: |
May 14, 2010 |
Current U.S.
Class: |
216/68 ;
118/723I; 156/345.33; 156/345.48; 427/569 |
Current CPC
Class: |
H01J 37/32532 20130101;
H01J 37/32541 20130101; H01J 37/3211 20130101; C23C 16/45565
20130101; H01J 37/3244 20130101; C23C 16/509 20130101; H01J 2237/33
20130101; C23C 16/5096 20130101 |
Class at
Publication: |
216/68 ;
156/345.48; 118/723.I; 156/345.33; 427/569 |
International
Class: |
H01L 21/306 20060101
H01L021/306; C23F 1/00 20060101 C23F001/00; B05D 1/00 20060101
B05D001/00; C23C 16/00 20060101 C23C016/00; H05H 1/24 20060101
H05H001/24 |
Claims
1. A lid assembly for a plasma chamber, comprising: a first annular
inductive coil nested with a first conductive ring.
2. The lid assembly of claim 1, wherein the first annular inductive
coil is disposed in an insulating channel nested with the first
conductive ring.
3. The lid assembly of claim 2, further comprising a field
concentrator disposed around the first annular inductive coil
inside the insulating channel.
4. The lid assembly of claim 3, further comprising a second annular
inductive coil disposed in a second insulating channel nested with
the first conductive ring.
5. The lid assembly of claim 4, wherein the first and second
annular inductive coils and the first conductive ring are arranged
concentrically.
6. The lid assembly of claim 4, wherein the first and second
annular inductive coils each comprise a metal tube.
7. The lid assembly of claim 6, wherein the first annular inductive
coil is nested in a central opening of the conductive ring and the
second annular inductive coil is nested about a peripheral edge of
the conductive ring.
8. A lid assembly for a plasma chamber, comprising: a gas
distributor; a support plate disposed around the gas distributor; a
conductive ring disposed around the gas distributor and coupled to
the support plate; an annular inductive coil disposed in an
insulating channel nested with the conductive ring; and a field
concentrator disposed in the insulating channel around the
inductive coil.
9. The lid assembly of claim 8, wherein the insulating channel is
concentrically disposed in a central opening of the conductive
ring, has an opening that faces the support plate, and has an
extension over an inner edge of the conductive ring.
10. The lid assembly of claim 9, wherein the support plate is
conductive and is electrically coupled to the conductive ring.
11. The lid assembly of claim 8, wherein the gas distributor is
coupled to a conduit through a central aperture of the support
plate, the conductive ring, and the annular inductive coil, the
support plate is electrically coupled to the conductive ring, the
annular conductive coil is electrically insulated from the support
plate and the conductive ring, and the annular conductive coil is
substantially coplanar with the conductive ring.
12. The lid assembly of claim 8, further comprising an isolator
disposed in the insulating channel, the isolator having a channel
into which the annular inductive coil fits.
13. The lid assembly of claim 12, wherein the annular inductive
coil is substantially coplanar with the conductive ring.
14. The lid assembly of claim 13, wherein the annular inductive
coil comprises a conduit for a thermal control medium.
15. A processing chamber for a semiconductor substrate, comprising:
a chamber body defining an interior region; a substrate support
disposed in the interior region; and a lid assembly disposed in the
interior region facing the substrate support, the lid assembly
comprising: a gas distributor; and a plasma source having a first
conductive surface that faces the substrate support, a second
conductive surface that faces away from the substrate support, and
a plurality of conductive coils disposed in the conductive plasma
source between the first surface and the second surface.
16. The processing chamber of claim 15, wherein each the conductive
coils is disposed in a conduit formed in the conductive plasma
source, and the conduit is lined with an insulating material.
17. The processing chamber of claim 16, wherein a magnetic field
concentrator is disposed within the conduit.
18. The processing chamber of claim 17, wherein each conductive
coil is formed with an internal pathway for a thermal control
medium.
19. The processing chamber of claim 18, wherein each conductive
coil comprises a plurality of conductive loops separated by
insulators.
20. A method of processing a substrate, comprising: disposing the
substrate on a substrate support in a processing chamber; providing
a plasma source facing the substrate support, the plasma source
comprising a plurality of conductive loops disposed in an
electrode, to define a processing region between the plasma source
and the substrate support; providing a gas mixture to the
processing region; grounding the electrode; and forming a plasma
from the gas mixture by applying electric power to the conductive
loops.
21. The method of claim 20, further comprising tuning the plasma
profile by applying different power levels to the conductive
loops.
22. The method of claim 21, further comprising circulating a
cooling medium through the conductive loops.
23. The method of claim 22, wherein the gas mixture is provided to
the processing region through an aperture in a central portion of
the plasma source.
24. The method of claim 22, wherein the gas mixture is provided to
the processing region through a plurality of apertures in the
plasma source.
Description
FIELD
[0001] Embodiments described herein generally relate to
manufacturing semiconductor devices. More specifically, embodiments
described herein relate to methods and apparatus for plasma
processing of substrates.
BACKGROUND
[0002] Plasma processing is commonly used for many semiconductor
fabrication processes for manufacturing integrated circuits,
flat-panel displays, magnetic media, and other devices. A plasma,
or ionized gas, is generated inside a processing chamber by
application of an electromagnetic field to a low-pressure gas in
the chamber, and then applied to a workpiece to accomplish a
process such as deposition, etching, or implantation. The plasma
may also be generated outside the chamber and then directed into
the chamber under pressure to increase the ratio of radicals to
ions in the plasma for processes needing such treatments.
[0003] Plasma may be generated by electric fields, by magnetic
fields, or by electromagnetic fields. Plasma generated by an
electric field normally uses spaced-apart electrodes to generate
the electric field in the space occupied by the gas. The electric
field ionizes the gas, and the resulting ions and electrons move
toward one electrode or the other under the influence of the
electric field. The electric field can impart very high energies to
ions impinging on the workpiece, which can sputter material from
the workpiece, damaging the workpiece and creating potentially
contaminating particles in the chamber. Additionally, the high
potentials accompanying such plasmas may create unwanted electrical
discharges and parasitic currents.
[0004] Inductively coupled plasmas are used in many circumstances
to avoid some effects of capacitively coupled plasmas. An inductive
coil is disposed adjacent to a plasma generating region of a
processing chamber. The inductive coil projects a magnetic field
into the chamber to ionize a gas inside the chamber. The inductive
coil is frequently located outside the chamber, projecting the
magnetic field into the chamber through a dielectric window. The
inductive coil is frequently driven by high-frequency
electromagnetic energy, which suffers power losses that rise faster
than the voltage applied to the inductive coil. Thus, strong
coupling of the plasma source with the plasma inside the chamber
decreases power losses. Control of plasma uniformity is also
improved by strong coupling between the plasma source and the
plasma.
[0005] As device geometry in the various semiconductor industries
continues to decline, process uniformity in general and plasma
uniformity in particular, becomes increasingly helpful for reliable
manufacture of devices. Thus, there is a continuing need for
inductive plasma processing apparatus and methods.
SUMMARY
[0006] Embodiments described herein provide a lid assembly for a
plasma chamber, the lid assembly having a first annular inductive
coil nested with a first conductive ring.
[0007] Other embodiments provide a processing chamber for a
semiconductor substrate, the processing chamber having a chamber
body that definines an interior region, a substrate support
disposed in the interior region, and a lid assembly disposed in the
interior region facing the substrate support, the lid assembly
having a gas distributor and a plasma source with a first
conductive surface that faces the substrate support, a second
conductive surface that faces away from the substrate support, and
a plurality of conductive coils disposed in the conductive plasma
source between the first surface and the second surface.
[0008] Other embodiments provide a method of processing a substrate
by disposing the substrate on a substrate support in a processing
chamber, providing a plasma source facing the substrate support,
the plasma source comprising a plurality of conductive loops
disposed in an electrode, to define a processing region between the
plasma source and the substrate support, providing a gas mixture to
the processing region, grounding the electrode, and forming a
plasma from the gas mixture by applying electric power to the
conductive loops.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] So that the manner in which the above recited features of
the present invention can be understood in detail, a more
particular description of the invention, briefly summarized above,
may be had by reference to embodiments, some of which are
illustrated in the appended drawings. It is to be noted, however,
that the appended drawings illustrate only typical embodiments of
this invention and are therefore not to be considered limiting of
its scope, for the invention may admit to other equally effective
embodiments.
[0010] FIG. 1 is a schematic cross-sectional view of a processing
chamber according to one embodiment.
[0011] FIG. 2 is a schematic cross-sectional view of a gas
distributor according to another embodiment.
[0012] FIG. 3 is an exploded view of a gas distributor according to
another embodiment.
DETAILED DESCRIPTION
[0013] FIG. 1 is a schematic cross-sectional diagram of a
processing chamber 100 according to one embodiment. The processing
chamber 100 comprises a chamber body 102, a substrate support 104,
and a gas distributor 106 facing the substrate support 104, which
cooperatively define a processing region 118. The gas distributor
106 comprises a showerhead 108 and a plasma source 110 surrounding
the showerhead 108. The plasma source 110 comprises a conductive
spacer 114 and a conductive coil 112 disposed inside the conductive
spacer 114. There may be one or more conductive coils 112 disposed
in the conductive spacer 114. The conductive spacer 114 may be a
disk-like member with channels or conduits housing the conductive
coils 112. Alternately, the conductive spacer 114 may be a
plurality of rings separating the conductive coils 112 and nesting
with the conductive coils 112. Each of the conductive coils 112 is
housed in a channel or recess 116 lined with an insulating
material. The insulating material of the channel or recess 116
prevents electric current travelling from the conductive coils 112
into the conductive spacer 114. The conductive coils 112 produce a
magnetic field in the processing region 118 that ionizes a
processing gas disposed therein to form a plasma. In some
embodiments, the conductive coil 112 may be a coil assembly
featuring a removable insulating member, as further described below
in connection with FIG. 2.
[0014] The conductive spacer 114 provides a large surface area
grounded electrode that faces the substrate support 104. The large
grounded electrode allows generation of higher voltages at the
substrate support using lower power levels. Disposing the
conductive coils 112 in the conductive spacer 114 also brings the
plasma source close to the plasma generation area of the processing
region 118, improving coupling efficiency with the plasma.
Additionally, the large grounded surface area of the conductive
spacer 114 reduces plasma sheath voltage in the chamber, which
reduces sputtering of chamber walls and chamber lid components,
reducing contamination of workpieces disposed on the substrate
support. Use of multiple conductive coils 112 also provides the
possibility of using different power levels on the coils to tune
the plasma profile in the processing region 118.
[0015] FIG. 2 is a schematic cross-sectional diagram of a lid
assembly 200 according to another embodiment. Similar to the gas
distributor 106 of FIG. 1, the lid assembly 200 comprises a
showerhead 202 and a plasma source 204. A gas conduit 206 connects
a gas source (not shown) to the showerhead 202, placing the gas
source in fluid communication with a processing chamber through
openings 208 in the showerhead 202.
[0016] The plasma source 204 comprises a conductive coil 210
disposed in a channel 212 formed between conductive gas
distribution members 214. The gas distribution members 214 may be
metal or metal alloy, and may be coated with a dielectric material,
if desired, or a chemically resistant or plasma resistant material,
such as yttria, in some embodiments. The conductive coil 210, of
which there may be more than one, may also be metal, metal alloy,
or a conductive composite such as a metal coated dielectric or a
metal composite featuring metals having different conductivities.
Material selection for the conductive coil 210 generally depends on
the desired thermal and electrical conductivity. Materials with
lower electrical conductivity are generally lower in cost, but a
conductive coil made from low conductivity materials may generate
unwanted heat, and may require excessive power to operate. Highly
conductive materials such as copper and silver may be used
proficiently for a conductive coil. Less conductive and lower cost
materials such as aluminum, zinc, or nickel may be included as
alloy or layer components.
[0017] Heat may be dissipated by forming the conductive coil 210
with a conduit for a thermal control medium, which may be a cooling
liquid such as water or a cooling gas such as nitrogen. The
conductive coil 210 may be an annular or torroidal tube in some
embodiments. The tube wall thickness may be specified based on
thermal and electrical conductivity needed. Cooling may be useful
when high power, for example greater than about 500 W, is to be
applied to the conductive coil 210. In one embodiment, a conductive
coil is a torroidal tube comprising a layer of copper and a layer
of silver.
[0018] The channel 212 is generally lined with an insulating member
216, which may be ceramic or plastic, Teflon, for example. The
insulating member 216 confines the electric current to the
conductive coil 210. The insulating material may be an insert that
fits into the channel 212, or in other embodiments, may be a liner
adhered to the inner surface of the channel 212. The embodiment of
FIG. 2 features two insulating members 216, each of which is an
annular member that fits inside a respective channel, one of the
insulating members 216 fitting inside the innermost channel 212,
which is a first channel in the embodiment of FIG. 2, and the other
insulating member 216 fitting inside the outermost channel 212,
which is a second channel in the embodiment of FIG. 2. Each of the
channels 212 has a conductive coil 210 disposed therein. In the
embodiment of FIG. 2, each conductive coil comprises two conductive
loops 218. A pair of conductive loops 218 rest inside the recesses
formed by the respective insulating members 216.
[0019] The two conductive loops 218 are electrically isolated, one
from the other, by respective isolators 220, which serve to
surround each conductive loop 218. In the embodiment of FIG. 2,
each isolator 220 is an annular dielectric member having a recess
224 into which a conductive loop 218 fits. The recess 224 of an
isolator 220 and the channel 212 into which the isolator 220 fits
generally face in opposite directions. Thus, each conductive loop
is surrounded on three sides by an isolator 220 and on one side by
an insulating member 216. It should be noted that the isolators 220
may have any convenient cross sectional shape. For example, in an
alternate embodiment, the isolators 220 may be rounded to follow
the contours of a rounded, tube-like, conductive loop 218, such
that the recess 224 has a rounded cross-sectional shape. In another
embodiment, the cross-sectional profile of each isolator 220 and/or
each recess 224 may be rectangular with beveled corners. In still
other embodiments, the conductive loops 218 may be formed with a
coating that isolates the loop. The isolators 220 may be any
insulating material, such as ceramic, glass, or plastic. In the
embodiment of FIG. 2, each isolator 220 is shown as a single piece
covering a single conductive loop 218, but in alternate
embodiments, an isolator may be formed to cover two neighboring
conductive loops 218 while disposing a wall between them.
[0020] A field concentrator 222 is disposed around each conductive
coil 210 to amplify the magnetic field produced by each conductive
coil 210. In the embodiment of FIG. 2, the concentrator 222 is
disposed around a pair of conductive loops 218 and their respective
isolators 220, but in other embodiments, each loop 218 may be
paired with a field concentrator 222, or more than two loops may be
coupled to a field concentrator 222. The field concentrator 222
focuses the magnetic field produced by each conductive coil 210
toward the plasma generation area of the processing chamber,
minimizing magnetic energy projecting away from the plasma
generation area. Each field concentrator 222 generally comprises
ferrite or other magnetically susceptible or magnetizable
materials, such as low coercivity materials. Thermal control of the
conductive coil 210 minimizes temperature variation of the field
concentrator 222, maintaining the magnetic properties thereof for
control of the magnetic field produced by the conductive coil
210.
[0021] The inductive coils 210 are interposed within the gas
distribution members 214 that nest with the insulating members 216
and cooperatively define the channels 212. Conductive members 226
may also be interposed with the inductive coils 210 and the gas
distribution members 214. In one embodiment, the conductive members
226 are rings that comprise metal, metal alloy, or metal mixtures,
each of which may be attached to a support member 228. The
insulating members 216 fit between the conductive members 226 and
the gas distribution members 214 to provide the channel 212 in a
substantially coplanar configuration with the conductive members
214 and 226, such that the inductive coils 210 are substantially
coplanar with the conductive members 214 and 226.
[0022] The support member 228 is generally also conductive. In some
embodiments, the support member 228 is a metal block. The support
member 228 has recesses 230 that, together with the conductive
members 226, define capture spaces 232 into which respective
shoulder portions 234 of each insulating member 216 are captured to
secure the insulating members 216 into the lid assembly 200. The
conductive members 214 and 226 allow for a large grounded surface
to be brought into close proximity to the plasma, enabling higher
bias voltage to be used on the substrate support at lower power
levels and lower heat input (FIG. 1). The lid assembly
configuration of FIG. 2 also brings the plasma source energy of the
inductive coils 210 into close proximity with gas in the processing
region, resulting in higher plasma density at lower power levels.
Use of multiple inductive coils such as the inductive coils 210
also enables tuning of the plasma profile generated in the chamber
by adjusting the power level applied to each individual coil.
[0023] The support member 228 comprises one or more conduits 236
that bring process gases to the conductive gas distribution members
214. Additionally, in some embodiments, the conductive gas
distribution members 214 may comprise conduits (not shown) to
disperse gas from the conduit 236 around the circumference of the
gas distribution member 214 for even gas distribution. By
interposing conductive gas distribution members 214 with inductive
coils 210, the apparatus 200 may be used as both a plasma source
and a showerhead. Gas flow is distributed evenly across the face of
the apparatus, and RF power is close-coupled to the process gas
exiting the various openings.
[0024] Thermal control may be enhanced by optionally including
thermal control conduits 240 in the support member 228. Locating
thermal control conduits in the support member 228 may enhance
thermal control of the field concentrators 222, which are otherwise
at least partially insulated from any thermal control fluid
circulating through the loops 218 by the isolators 220. Thermal
control in the vicinity of the field concentrators 222 may be
advantageous for maintaining electromagnetic properties of the
field concentrators 222. Also optionally, a cushion 238 may be
disposed between the field concentrators 222 and the support member
228 to avoid any damage to the field concentrators 222, which may
be easily damaged by direct contact with the metal surface of the
support member 228. The cushion 238 may be a thermally conductive
material such as Grafoil.RTM., which is a flexible graphitic
sealing material manufactured by Natural Graphite Operations, of
Lakewood, Ohio, a subsidiary of GrafTech International, and
distributed by Leader Global Technologies, of Deer Park, Tex.
[0025] In general, the lid assembly 200 may have any convenient
shape or size for processing substrates of any dimension. The lid
assembly 200 may be circular, rectangular, or any polygonal shape.
The lid assembly 200 may be of a size and shape adapted for
processing semiconductor wafers for making semiconductor chips of
any description, or the lid assembly 200 may be of a size and shape
adapted for processing semiconductor panels such as large-area
display or solar panels. Other types of substrates, such as LED
substrates or magnetic media substrates, may also be processed
using a lid assembly as herein described. In some embodiments, the
conductive coil (or coils) 210 may be disposed in a concentric
circular shape, in a concentric non-circular (rectangular,
polygonal, square, or irregular) shape, or in a non-concentric
shape such as a boustrophedonic or zig-zag pattern. In another
non-concentric embodiment, the conductive coil (or coils) 210 may
be disposed in a spiral pattern.
[0026] In some embodiments, a lid assembly may be similar to the
lid assembly 200 of FIG. 2, with some differences. In one
embodiment, the lid assembly may have a curved surface facing the
substrate support, curved in a convex or concave sense. In one
aspect, the entire plasma source may be curved (i.e. the surface of
the plasma source facing the substrate support and the surface
facing away from the substrate support are both convex or concave).
In another aspect, only the surface of the lid assembly facing the
substrate support may be curved. In one embodiment, multiple
showerheads may be provided, especially for large area lid
assemblies. In one embodiment, gas may be injected through the
conductive members 226 by providing one or more conduits through
the support member 228. In other embodiments, conductive coils may
be provided that comprise a single electrical circuit, rather than
multiple discrete circuits. For example, in one embodiment, the
conductive coil may be arranged in a planar, circular or
rectangular spiral shape nested with, or disposed in, a
complementary conductive member such that the conductive member and
the conductive coil form a substantially planar plasma source. Such
a spiral shape may also be z-displaced such that the plasma source
is not planar, but has a z-dimension in a convex or concave
sense.
[0027] FIG. 3 is an exploded view of a lid assembly 300 according
to another embodiment. The lid assembly 300 is similar in most
respects to the lid assembly 200 of FIG. 2, and identical features
are labeled with the same identifying labels. The lid assembly 300
comprises a conduit 206 for delivering gas to the process region of
the chamber on which the lid assembly 300 is installed. The lid
assembly 300 further comprises a first RF coil 302 and a second RF
coil 304 similar to the first RF coil, with the first RF coil 302
shown in exploded format. The first RF coil 302 comprises a
plurality of conductors 306 disposed in an insulating channel 308.
In the embodiment of FIG. 3, the conductors 306 are circular and
concentric, but in alternate embodiments the conductors 306 may be
disposed in any convenient configuration, as described herein. Each
of the conductors 306 has a contact 310 for supplying power to the
conductor 306. As described elsewhere herein, the conductors 306
may be conductive tubes configured to carry a coolant in addition
to electric power. Thus, the contacts 310 may also be used to
provide coolant to the conductors 306.
[0028] The conductors 306 are generally metal, or other
electrically conductive material. The metal may be a single metal,
an alloy, a mixture, or another combination of metals. The
conductors 306 may also be coated with a non-conductive material,
such as ceramic or polymer, in some embodiments. In one embodiment,
the conductors 306 are copper tubes plated with silver. The metals
to be used generally depend on the electrical and thermal
properties needed for the particular embodiment. In high power
applications, higher electrical conductivity will generally result
in lower thermal budget, so more conductive materials may be
advantageous. It should be noted that when multiple RF coils are
used, each of the coils may have a different composition. For
example, silver plated copper tubes may have different thicknesses
of silver plating or different tube wall thicknesses to provide
differential conductivity among the tubes. In other embodiments,
each RF coil may have only one conductor, or more than two
conductors.
[0029] An insulator 312 is disposed over the conductors 306 so that
the conductors 306 are surrounded by insulative material. This
prevents electric power from flowing to the conductive rings 314
and 316 interposed between the first and second RF coils 302 and
304. The insulator 312 comprises a wall that is not visible in the
top-perspective view of FIG. 3. The wall extends between the two
conductors 306 to prevent electrical cross-talk between the
conductors 306 in a given RF coil 302 or 304. Thus, each conductor
306 is surrounded by insulative material. When power is provided to
the conductors 306, a magnetic field is generated by the conductors
306. A field concentrator 318 is disposed partially around the
conductors 306 to focus and direct the magnetic field in the
direction of the processing zone for improved efficiency.
[0030] The insulator 312 further comprises a passage 320 for each
contact 310. The passages 320 pass through openings in the field
concentrator 318 to provide a pathway for the contacts 310 to be
coupled to electric power while preventing electrical contact
between the contacts 310 and the field concentrator 318. The
contacts protrude through the field concentrator 318, where they
may be coupled to an RF source.
[0031] As with the embodiment of FIG. 2, any number of RF coils may
be disposed in the lid assembly 300. Process gases may also be
provided through the conductive rings 314 and 316, in addition to
or in place of the conduit 206, by providing conduits in the
conductive rings 314 and 316 with openings to release process gases
into the processing zone. The lid assembly 300 may also be formed
with a curvature according to any of the embodiments described
herein.
[0032] Embodiments disclosed herein also provide a method of
processing a substrate on a substrate support in a process chamber.
A plasma source may be provided in a position facing the substrate
support to form a plasma for processing the substrate. The method
comprises providing a plasma source that has a plurality of
conductive loops disposed in an electrode, providing a processing
gas to the chamber, grounding the electrode, and forming a plasma
from the processing gas by applying power to the conductive loops.
The conductive loops may be electrically insulated from the
electrode by coating, wrapping, or situating the loops in an
electrically insulating material, which may be a container, such as
a channel formed in the electrode, a coating applied to the
conductive loops, or a liner disposed inside a channel formed in
the electrode. RF power is applied to the loops, and may be
controlled independently to shape the plasma density in the process
chamber. The conductive loops may be thermally controlled, if
desired, by circulating a thermal control medium, such as a cooling
fluid, through tubular conductive loops.
[0033] The conductive loops may be substantially coplanar with the
electrode in some embodiments. In other embodiments, the electrode
may be non-planar, with conductive loops disposed therein. In still
other embodiments, the conductive loops may be partially disposed
in the electrode and partially disposed outside the electrode, with
any portions of the conductive loops disposed outside the electrode
contained or encapsulated in an insulating material.
[0034] The plasma may be further enhanced by providing a field
concentrator disposed to concentrate the field inside the plasma
region of the processing chamber. For example, the field
concentrator may generally be disposed opposite the substrate
support, such that the conductive loops are between the field
concentrator and the substrate support. Such positioning prevents
development of magnetic field lines outside the chamber, and
focuses the plasma source energy in the processing gas.
[0035] While the foregoing is directed to embodiments of the
present invention, other and further embodiments of the invention
may be devised without departing from the basic scope thereof, and
the scope thereof is determined by the claims that follow.
* * * * *