U.S. patent application number 11/514676 was filed with the patent office on 2007-03-08 for apparatus and methods for using high frequency chokes in a substrate deposition apparatus.
This patent application is currently assigned to APPLIED MATERIALS, INC.. Invention is credited to Carl A. Sorensen.
Application Number | 20070051388 11/514676 |
Document ID | / |
Family ID | 37878104 |
Filed Date | 2007-03-08 |
United States Patent
Application |
20070051388 |
Kind Code |
A1 |
Sorensen; Carl A. |
March 8, 2007 |
Apparatus and methods for using high frequency chokes in a
substrate deposition apparatus
Abstract
In certain aspects, a substrate deposition apparatus, including
a gas tube coupled to a gas source, an RF power source and a
substrate processing chamber, is provided. The gas tube is adapted
to carry process gas and cleaning plasma from the gas source/remote
plasma gas source to the substrate processing chamber and the RF
power source is adapted to couple RF power to the substrate
processing chamber. Furthermore an RF choke coupled to the RF power
source and the gas source wherein the RF choke is adapted to
attenuate a voltage difference between the RF power source and the
gas source to prevent plasma formation in the gas tube during
substrate processing. Numerous other aspects are provided.
Inventors: |
Sorensen; Carl A.; (Morgan
Hill, CA) |
Correspondence
Address: |
DUGAN & DUGAN, PC
55 SOUTH BROADWAY
TARRYTOWN
NY
10591
US
|
Assignee: |
APPLIED MATERIALS, INC.
|
Family ID: |
37878104 |
Appl. No.: |
11/514676 |
Filed: |
September 1, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60714723 |
Sep 6, 2005 |
|
|
|
Current U.S.
Class: |
134/1.1 ;
118/715; 118/723I; 118/723IR; 118/723R; 427/569 |
Current CPC
Class: |
C23C 16/4405 20130101;
H05H 1/46 20130101; H01J 37/32174 20130101; C23C 16/507 20130101;
B08B 7/0035 20130101; H01J 37/32082 20130101; C23C 16/452
20130101 |
Class at
Publication: |
134/001.1 ;
118/715; 118/723.00R; 118/723.00I; 118/723.0IR; 427/569 |
International
Class: |
B08B 6/00 20060101
B08B006/00; H05H 1/24 20060101 H05H001/24; C23C 16/00 20060101
C23C016/00 |
Claims
1. A substrate deposition apparatus, comprising: a gas tube coupled
to a gas source, an RF power source and a substrate processing
chamber, wherein the gas tube is adapted to carry gas from the gas
source to the substrate processing chamber, and wherein the RF
power source is adapted to couple RF power to the substrate
processing chamber; and an RF choke coupled to the RF power source
and the gas source, wherein the RF choke is adapted to attenuate a
voltage difference between the RF power source and the gas
source.
2. The apparatus of claim 1, wherein the gas tube is disposed
within the RF choke.
3. The apparatus of claim 1, wherein the RF choke includes a wire
wrapped into a coil.
4. The apparatus of claim 3, wherein the RF choke further includes
a core disposed inside the wire wrapped into a coil.
5. The apparatus of claim 4, wherein the core is adapted to ensure
the pitch of the coil is substantially constant.
6. The apparatus of claim 3, wherein the wire is coated with a
dielectric material.
7. The apparatus of claim 6, wherein the RF choke further includes
a core disposed inside the wire wrapped into a coil.
8. The apparatus of claim 1, wherein the gas tube includes a
dielectric material.
9. The apparatus of claim 8, wherein the RF choke includes a wire
wrapped into a coil.
10. The apparatus of claim 9, wherein the RF choke further includes
a core disposed inside the wire wrapped into a coil.
11. The apparatus of claim 10, wherein the core is adapted to
ensure the pitch of the coil is substantially constant.
12. The apparatus of claim 3, wherein the wire is coated with a
dielectric material.
13. The apparatus of claim 12, wherein the gas tube is disposed
inside the coil.
14. The apparatus of claim 1, wherein the RF choke is further
adapted to approximately uniformly attenuate the voltage difference
between the RF power source and the gas delivery system.
15. A method, comprising: providing a gas tube, a gas source, an RF
power source and a substrate processing chamber; carrying gas from
the gas source to the substrate processing chamber via the gas
tube; coupling RF power to the substrate processing chamber;
providing an RF choke; attenuating a voltage difference between the
RF power source and the gas source with the RF choke.
16. The method of claim 15, wherein providing an RF choke includes
disposing the RF choke around the gas tube.
17. The method of claim 15, wherein providing an RF choke includes
providing a wire wrapped into a coil.
18. The method of claim 17, wherein providing a wire wrapped into a
coil includes disposing the wire around the gas tube.
19. The method of claim 18, wherein disposing the wire around the
gas tube further includes ensuring the pitch of the wire is
substantially constant.
20. The method of claim 15, wherein providing a gas tube includes
providing dielectric material.
21. The method of claim 20, wherein providing the RF choke includes
providing a wire wrapped into a coil.
22. The method of claim 21, wherein providing a wire wrapped into a
coil includes disposing the wire around the gas tube.
23. The method of claim 22, wherein disposing the wire around the
gas tube further includes ensuring the pitch of the wire is
substantially constant.
24. The method of claim 17, wherein providing a wire wrapped into a
coil includes providing a wire coated with dielectric material.
25. The method of claim 24, wherein providing a wire coated with a
dielectric material includes disposing the wire coated with a
dielectric material around the gas tube.
26. A choke for use with a substrate processing chamber,
comprising: a wire formed into a coil; and a form disposed inside
the coil, wherein the form is adapted to ensure the pitch of the
coil is substantially constant, and wherein the wire is coated with
a dielectric material.
27. The choke of claim 26, further including a gas tube disposed
inside the form.
28. The choke of claim 26, wherein the choke is adapted to
approximately uniformly attenuate a voltage difference between an
RF power source and a gas delivery system.
Description
RELATED APPLICATIONS
[0001] The present application claims priority to U.S. Provisional
Patent Application Ser. No. 60/714,723 filed Sep. 6, 2005 and
entitled "APPARATUS AND METHODS FOR AN RF CHOKE" which is hereby
incorporated by reference herein for all purposes.
FIELD OF THE INVENTION
[0002] The present invention relates generally to high or radio
frequency (RF) chokes and specifically to RF chokes for plasma
processing chambers.
BACKGROUND
[0003] With each successive technology generation, substrate
processing chambers may increase in size to accommodate larger
substrates. Larger substrate processing chambers may require an
increase in the RF power used to perform a substrate plasma process
in the substrate processing chamber. What is needed are improved
methods and apparatus that allow existing processing chambers to be
cost effectively enhanced to support processing operations that use
higher RF powers.
SUMMARY OF THE INVENTION
[0004] The invention provides a substrate deposition apparatus,
comprising a gas tube coupled to a gas source, an RF power source
and a substrate processing chamber. The gas tube is adapted to
carry gas from the gas source to the substrate processing chamber,
and the RF power source is adapted to couple RF power to the
substrate processing chamber. Furthermore, an RF choke is coupled
to the RF power source and the gas source wherein the RF choke is
adapted to attenuate a voltage difference between the RF power
source and the gas source.
[0005] Other features and aspects of the present invention will
become more fully apparent from the following detailed description,
the appended claims, and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a schematic diagram depicting a substrate
processing apparatus in accordance a first embodiment of the
present invention.
[0007] FIG. 2 is a perspective diagram depicting the RF choke of
FIG. 1 in accordance with the first embodiment of the present
invention.
[0008] FIG. 3 is a schematic diagram depicting a substrate
processing apparatus in accordance with a second embodiment of the
present invention.
[0009] FIG. 4 is a perspective diagram depicting the RF choke of
FIG, 3 in accordance with a second embodiment of the invention.
[0010] FIG. 5 is a perspective view of a top portion of a substrate
processing apparatus in accordance with a third embodiment of the
present invention.
[0011] FIGS. 6A, 6B, 6C and 6D are perspective, side, end, and
detail views, respectively, of an RF choke in accordance with a
third embodiment of the invention.
DETAILED DESCRIPTION
[0012] Substrate processing chambers may be adapted to perform a
cleaning process using a remotely generated "cleaning" plasma that
is delivered to the chamber via the same channel that is used for
delivering the regular process gases to the chamber. Thus, the
cleaning process may use a cleaning plasma tube, which may be
coupled to an RF power source, external to the substrate processing
chamber. Accordingly, an RF power source may be coupled to both the
substrate plasma processing chamber and the cleaning plasma tube.
The cleaning plasma tube may be coupled to a gas source and the RF
power source. However, this may lead to undesired electrical
coupling of the RF power source to the gas delivery device. To
avoid this according to the present invention, a device may be
employed to electrically decouple or attenuate the voltage
difference between the RF power and the gas source. This may be
accomplished by placing a device such as a dielectric gas tube
(e.g., ceramic plasma tube) between the RF power source and the gas
delivery device that may also serve as the cleaning plasma tube.
However, this may result in a localized high density electrical
field, due to non uniform attenuation of the voltage difference
between the gas source and the RF power source, which may cause
unintended plasma in the shared dielectric gas tube/cleaning plasma
tube during substrate processing.
[0013] A more uniform attenuation of the voltage may allow
relatively higher RF power to be delivered to the substrate
processing chamber before plasma is ignited in the plasma tube. In
other words, the present invention may be used to prevent process
plasma from forming in the cleaning plasma tube during substrate
processing using higher RF powers. A resistor may be placed between
RF power source and the gas delivery apparatus and may ensure an
approximately uniform attenuation of voltage difference between the
RF power source and the gas delivery system. However, the resistor
may be expensive, susceptible to damage and take up an undesired
amount of volume. Therefore, there may be a desire for an
inexpensive, compact apparatus adapted to ensure an approximately
uniform attenuation of the voltage from the RF power source and the
gas delivery apparatus.
[0014] In accordance with the present invention, an RF choke is
provided. In a first embodiment, the RF choke may include a wire
wrapped around a hollow plastic core or form. The plastic core may
include grooves machined into the surface so as to allow the wire
to form a coil traversing the length of the plastic core.
Alternatively, in a second embodiment of the RF choke, a wire with
a dielectric coating may be provided. The pitch between the wires
may be established by the thickness of the dielectric coating on
the conductive portion of the wire when the wire may be wrapped
around an object such as a form or a tube.
[0015] The RF choke may be electrically coupled to a gas source, an
RF power source and a substrate processing chamber. The coupling of
the RF choke, or specifically, the coiled wire to the RF power
source and the gas source, may induce a voltage drop along the
length of the wire. By providing a wire wrapped into a coil, in
accordance with the first two embodiments, an approximately uniform
voltage drop along the length of the wire may be realized. Thereby,
the voltage drop that induces plasma in the substrate processing
chamber and/or gas tube may be realized and/or repeatable. These
aspects of the invention are discussed below.
[0016] FIG. 1 is a schematic drawing depicting a substrate
processing apparatus 100 in accordance a first embodiment of the
present invention. The substrate processing apparatus 100 (e.g.,
embodied as Plasma Chamber Models 15K, 20K, 25K and/or 25KA
manufactured by AKT, Inc. of Santa Clara, Calif.) may include an
inventive RF choke 102 disposed coaxially around a gas tube 104.
The gas tube 104 (e.g., formed from ceramic, quartz, and/or the
like) may be coupled to a gas source 106 (e.g., a gas panel, gas
lines, and/or the like) via a gas delivery device 108 (e.g.,
stainless steel gas line, gas distribution block, and/or the like).
Furthermore, the gas tube 104 may be coupled to the substrate
processing chamber 110 via a chamber distribution device 112 (e.g.,
stainless steel tubing, machined copper block, shower head, and/or
the like). The RF choke 102, which may be disposed coaxially around
the gas tube 104, may be electrically coupled to the gas delivery
device 108. As previously discussed, the gas delivery device 108
may be coupled to the gas source 106. In addition, the RF choke 102
may be coupled to the RF power source 114 (e.g., RF generator and
matching network, variable frequency network, and/or the like) via
an RF delivery device 116 (e.g., a coaxial cable, bus bar, and/or
the like).
[0017] With reference to FIG. 1, during a substrate fabrication
process in the substrate processing apparatus 100, the RF power
source 114 may couple RF power to both the RF choke 102 and/or the
substrate processing chamber 110. Furthermore, the gas source 106
may provide process gases to the substrate processing chamber 110
via the gas delivery device 108, gas tube 104 and/or chamber
distribution device 112. In this manner, plasma may be formed in
the substrate processing chamber 110 and/or gas tube 104.
[0018] Still with reference to FIG. 1, plasma may be formed in the
substrate processing chamber 110 by flowing gas and coupling RF
power to the chamber distribution device 112. The plasma may be
employed to perform material removal and/or deposition processes
(e.g., CVD, etch and/or the like) on the substrate. During the
material removal and/or deposition processes, the voltage level of
the chamber distribution device 112 (Vbs) may be known and/or
repeatable so as to induce plasma in the substrate processing
chamber 110 without forming plasma in the gas tube 104.
[0019] Alternatively, there may be a need to perform a clean
process in the substrate processing chamber 110. The clean process
may be performed by flowing cleaning plasma gas to the gas tube 104
via the gas delivery device 108 (e.g., remote plasma clean source).
During the flow of the cleaning plasma gas, the RF power source 114
may couple RF power to the RF choke 102 via the RF delivery device
116. In this manner, plasma may be maintained in the gas tube 104.
Furthermore, the voltage level of the chamber distribution device
112 (Vbt) that induces plasma in the gas tube 104 may be known. The
plasma may provide reactive species such chlorine which may flow to
the substrate processing chamber 110 via the chamber distribution
device 112 to perform the clean process.
[0020] Still with reference to FIG. 1, plasma in the gas tube 104
may be maintained in a known and/or repeatable manner by
controlling the distribution of the voltage along the length of the
RF choke 102. For example, by having an approximately uniform
distribution of voltage along the length of the RF choke 102, the
RF power output by the RF power source 114 that may maintain plasma
(and/or in some embodiments, induce plasma or prevent reactive
species from recombining into a more stable state) in the gas tube
104 may be determined and thereby be more predictable and/or
repeatable. Additionally, different gas compositions flowed from
the remote plasma gas source 106 to the gas tube 104 may form
plasma at different Vbt voltage levels. Thus, for a variety of gas
compositions, the voltage level Vbt that may induce plasma in the
gas tube 104 may be known and/or repeatable.
[0021] FIG. 2 is a perspective drawing depicting the RF choke 102
in accordance the first embodiment of the present invention. The RF
choke 102 may include a core 200 (e.g., hollow plastic cylinder or
the like) a coiled wire 202 (e.g., 17 AWG nickel-chromium or the
like), a gas end bolt 204 (e.g., stainless steel threaded bolt or
the like) and a RF end bolt 206 (e.g., stainless steel threaded
bolt or the like).
[0022] With reference to FIG. 2, the core 200 may be disposed
internal to the approximately cylindrical geometry formed by the
coiled wire 202 and serve as a form to support the coiled wire 202.
Furthermore, the core 200 may include a continuous groove 208 on
the surface in which the coiled wire 202 may be disposed to
maintain the position of the wire and prevent short circuiting of
coils. On a first end of the core 200 the gas end bolt 204 may be
coupled to both the coiled wire 202 and the core 200. A portion of
the gas end bolt 204 may protrude from a first end of the core 200.
Additionally, the RF end bolt 206 may be coupled to both the coiled
wire 202 and the core 200. A portion of the RF end bolt 206 may
protrude from a second end of the core 200. The coiled wire 202 may
be coupled to the RF delivery device 116 via the RF end bolt 206.
In addition, the coiled wire 202 may also be coupled to the gas
delivery device 108 via the gas end bolt 204.
[0023] Still with reference to FIG. 2, during the substrate and/or
clean process the RF end bolt 206 may be electrically excited to a
voltage, Vbs and/or Vbt or any other suitable voltage, by the RF
power source 114. In addition, the gas end bolt 204 may be at or
near earth ground voltage (e.g., near zero voltage or the like).
Thus, the coiled wire 202 may have a voltage drop along the length
of the wire that is approximately equal to Vbs and/or Vbt or any
other suitable voltage. Furthermore, the voltage drop along the
length of the coiled wire 202 may be approximately uniform. By
having an approximately uniform voltage drop that may be
approximately equal to Vbs and/or Vbt or any other suitable
voltage, the RF power output from the RF power source 114 which may
maintain (or induce ignition of) the plasma in the gas tube 104
and/or substrate processing chamber 110 may be approximately
determined and/or repeatable.
[0024] FIG. 3 is a schematic drawing depicting a substrate
processing apparatus 300 in accordance a second embodiment of the
present invention. The substrate processing apparatus 300 may
include an insulated RF choke 302 disposed around the gas tube 104.
The gas tube 104 may be coupled to the gas source 106 via a gas
delivery device 108. Furthermore, the gas tube 104 may be coupled
to the substrate processing chamber 110 via a chamber distribution
device 112. The insulated RF choke 302, which may be disposed
around the gas tube 104, may be electrically coupled to the gas
delivery device 108. As previously discussed, the gas delivery
device 108 may be coupled to the gas source 106. In addition, the
insulated RF choke 302 may be coupled to the RF power source 114
(e.g., RF generator and matching network, variable frequency
network, and etc.) via a RF delivery device 116 (e.g., coaxial
cable, bus bar and etc.)
[0025] FIG. 4 is a perspective drawing depicting an RF choke 302 in
accordance with a second embodiment of the invention. The insulated
RF choke 302 may include an insulated coiled wire 304, the gas end
bolt 204 and the RF end bolt 206. The gas end bolt 204 may couple
the insulated RF choke 302 to the gas delivery device 108.
Furthermore, the RF end bolt 206 may couple the insulated RF choke
302 to the chamber distribution device 112.
[0026] Similar to the first embodiment in operation, during the
substrate and/or clean process, the RF end bolt 206 may be
electrically excited to a voltage by the RF power source 114. In
addition, the gas end bolt 204 may be at a voltage level near earth
ground. Thus, the insulated coiled wire 304 may have a voltage drop
along the length of the wire that is approximately equal to voltage
Vbs and/or Vbt or any other suitable voltage. Furthermore, the
voltage drop along the length of the insulated coiled wire 304 may
be approximately uniform. In this manner, the RF power output from
the RF power source 114 which may induce ignition of the plasma in
the gas tube 104 may be approximately known and/or repeatable.
[0027] Turning to FIG. 5, a lid 502 of a processing chamber is
depicted including a remote cleaning plasma source 504 in fluid
communication with a diffuser 506 (leading into the processing
chamber) via a gas tube 508 surrounded by an RF choke 510. The lid
502 may be employed to couple energy (e.g., RF, microwave, etc.) to
a fluid and distributing the fluid to the processing chamber. The
gas tube 508 may be coupled to the diffuser 506 via a gas input
512. A matching network 514 may be coupled to the RF choke 510 and
the lid 502. A grounded connector 516 may couple the remote
cleaning plasma source 504 and the RF choke 510 to electrical
ground (e.g., approximately zero volts).
[0028] With reference to FIG. 5, the remote cleaning plasma source
504 may provide a fluid. The fluid may be employed in the
processing chamber to process substrates, clean the chamber, or any
other suitable purpose. The fluid may be fluid (e.g., gas,
vaporized water, etc.) or any other fluid suitable for use in the
processing chamber. Additionally or alternatively, the fluid may be
ionized (e.g., into a plasma) or imparted other similar
characteristics so as to perform the processes in the processing
chamber. The remote cleaning plasma source 504 may comprise
aluminum and/or any material suitable to provide the fluid. For
example, in the same or alternative embodiments, portions of the
remote cleaning plasma source 504 may include ceramic parts to
ensure that energy (e.g., electrical) is not exchanged between the
fluid and the lid.
[0029] The remote cleaning plasma source 504 may be adapted to
provide a fluid for processing. For example, the remote cleaning
plasma source 504 may be adapted to vaporize water to form gaseous
water (e.g., steam). Such fluid may be employed by the processing
chamber.
[0030] The diffuser 506 may comprise anodized aluminum although any
suitable material may be employed to distribute the fluid. As
depicted in FIG. 5, the diffuser 506 may have a flat circular shape
although any suitable shape and/or configurations of shapes may be
employed. The diffuser 506 may also have holes adapted to pass the
fluid to the processing chamber. As discussed above the diffuser
506 may be in fluid communication with the remote cleaning plasma
source 504 via the gas tube 508.
[0031] The diffuser 506 may be employed to distribute the fluid in
a desired manner. For example, it may be desired to distribute the
fluid evenly inside the processing chamber to ensure uniform
processing. Alternatively, the diffuser 506 may distribute the
fluid in a non-uniform manner to ensure that the fluid concentrates
in desired regions of the processing chamber.
[0032] As depicted in FIG. 5, the gas tube 508 may be a single
circular tube 508 although any suitable shapes and/or configuration
of shapes may be employed. The gas tube 508 may comprise anodized
aluminum although any suitable material or combination of materials
may be employed.
[0033] The gas tube 508 may be adapted to convey the fluid from the
remote cleaning plasma source 504 to the diffuser 506. The gas tube
508 may also insulate (e.g., electrically) the fluid from
electrical or other energy sources. By insulating the fluid from
the energy sources, the gas tube 508 may ensure that a desired
amount of energy is coupled to the fluid. In addition or
alternatively, the gas tube 508 may be adapted to hold other
components of the present invention. For example, as will be
discussed below, the gas tube 508 may be adapted to mechanically
support other components of the present invention.
[0034] Still with reference to FIG. 5, the RF choke 510 may be
disposed around the gas tube 508. The RF choke 510 is depicted as a
single coil disposed around the gas tube 508 although other
suitable configurations may be employed. Similar to the embodiment
described above with reference to FIGS. 1-4, the RF choke 510 may
be employed to couple energy to the fluid being conveyed by the gas
tube 508. The gas input 512 may comprise aluminum although any
suitable material may be employed. The gas input 512 is depicted in
FIG. 5 as a cube shaped although any suitable shape may be
employed. The gas input 512 may be adapted to couple the gas tube
508 to the diffuser 506. The gas input 512 may be employed to
convey the fluid from the gas tube 508 to the diffuser 506. In the
same or alternative embodiments, the gas input 512 may be employed
to electrically insulate the diffuser 506 from the gas tube
508.
[0035] The matching network 514 may be coupled to the RF choke 510
and the lid 502. The matching network 514 may include other
components that are not discussed in detail in this application.
The components may be inductors and/or capacitors although other
suitable components may be employed. The external shell of the
matching network 514 may be aluminum although any suitable material
may be employed.
[0036] The matching network 514 may be adapted to couple a source
(e.g., electrical) to the lid 502 via the choke 510. The matching
network 514 may be employed to match the electrical load presented
to the matching network 514 (e.g., electrical load of the
processing chamber, RF choke, etc.) to the load of the source. In
the same or alternative embodiments, the matching network 514 may
couple energy to the processing chamber via the RF choke 510.
[0037] The grounded connector 516 may comprise aluminum although
any suitable material may be employed. The grounded connector 516
is depicted in FIG. 5 as a cube shaped device although any suitable
shape may be employed. The grounded connector 516 may be adapted to
couple an end of the RF choke 510 to ground. In the same or
alternative embodiments, the grounded connector 516 may also be
coupled to the remote cleaning plasma source 504. By coupling an
end of the RF choke 510 to ground, the energy being coupled to the
RF choke 510 via the matching network 514 may be coupled to ground
through the RF choke.
[0038] FIG. 6A depicts a perspective view of an RF choke form 602
adapted to receive and support a conductive coil 604 (which is
partially shown wrapped about the form) coaxially about the gas
tube 508 of FIG. 5. FIGS. 6B and 6C depict side and end views of
the form of FIG. 6A. FIG. 6D depicts a close-up detail view of
grooves milled into the surface of the form to space and insulate
the conductive coils from each other. Note that the drawings are
not to scale and the dimensions may be adjusted to accommodate
different sized chambers that use different amounts of RF power.
For example, the Plasma Chamber Model 40K manufactured by AKT, Inc.
may use a longer RF choke than the Model 25K or 15K mentioned
above.
[0039] The RF choke form 602 may comprise a plastic such as
polyamide although any suitable material may be employed. For
example, the RF choke form 602 may comprise a ceramic material in
addition to other materials. The RF choke form 602 may be adapted
to receive and support the conductive coil 604, as will be
described below with reference to FIGS. 6B and 6D.
[0040] With reference to FIG. 6B, the RF choke form 602 may have
the conductive coil 604 wrapped around the external surface 606 of
the RF choke form 602. Note that the conductive coil may comprise a
continuous wire wrapped around the RF choke form 602. In the same
or alternative embodiments, it may be desired to control the space
between each loop of the wire. Accordingly, the RF choke form 602
may be adapted to control the space, as will be described
below.
[0041] With reference to FIG. 6D, the RF choke form 602 may be
adapted to receive and hold the conductive coil 604 with a groove
608 in the external surface 606 of the RF choke form 602. The
conductive coil 604 may be disposed in the grooves 608.
[0042] Although the groove 608 is depicted as u-shaped valleys, any
suitable shape may be employed. For example, in an alternative
embodiment, the groove 608 may be v-shaped or rectangular shaped.
The groove 608 may be any suitable depth suitable for controlling
the depth of the wire of the conductive coil 604 in the groove 608.
Also, as depicted in FIG. 6D, the groove 608 is a continuous
feature along the length of the RF choke form 602. In alternative
embodiments, the groove 608 may comprise a plurality of
features.
[0043] The foregoing description discloses only exemplary
embodiments of the invention. Modifications of the above disclosed
apparatus and method which fall within the scope of the invention
will be readily apparent to those of ordinary skill in the art.
Accordingly, while the present invention has been disclosed in
connection with exemplary embodiments thereof, it should be
understood that other embodiments may fall within the spirit and
scope of the invention, as defined by the following claims.
* * * * *