United States Patent [191
`Collins et a1.
`
`‘[11] Patent Number:
`[451 Date of Patent:
`
`5,065,118
`Nov. 12, 1991
`
`[54] ELECTRONICALLY TUNED VHF/UHF
`MATCHING NETWORK
`[75] Inventors: Kenneth S. Collins, Morgan Hill;
`Craig A. Roderick, San Jose, both of
`Calif.
`[73] Assignee: Applied Materials, Inc., Santa Clara,
`Calif.
`[21] Appl. No.: 558,290
`[22] Filed:
`Jul. 26, 1990
`
`[51] Int. Cl.5 ............................................. .. H01? 5/04
`[52] US. Cl. ................................... .. 333/33; 333/24.1;
`333/160
`[58] Field of Search ............ .. 333/160, 161, 156, 17.3,
`333/32, 33, 24.1, 205, 207, 22 F, 24.2
`References Cited
`U.S. PATENT DOCUMENTS
`
`[56]
`
`3,384,841 5/1968 Di Piazza .......................... .. 333/160
`
`FOREIGN PATENT DOCUMENTS
`
`882121 11/1961 United Kingdom .............. .. 333/160
`
`OTHER PUBLICATIONS
`Moreno, Microwave Transmission Design Data, Dover
`Pub1., N.Y., N.Y., 1948, title page and pp. 103-106.
`Primary Examiner-Paul Gensler
`Attorney, Agent, or Firm-Robert J. Stern; Douglas L.
`Weller; Paul L. Hickman
`[57]
`ABSTRACT
`A matching network matches an output impedance of a
`source with an input impedance of a load. The matching
`network includes a plurality of transmission line stubs.
`Each transmission line stub includes a ?rst transmission
`line conductor, a second transmission line conductor
`running parallel to but not in electrical contact with the
`?rst transmission line conductor, and ferrite dielectric
`material between the ?rst transmission line conductor
`and the second transmission line conductor. A magnetic
`?eld is used to vary the relative permeability of the
`ferrite dielectric material.
`
`1214333 4/1960 France .............................. .. 333/160
`
`21 Claims, 3 Drawing Sheets
`
`21 33
`
`45
`
`29
`
`22
`
`SOURCE
`
`DC
`POWER
`SUPPLY
`
`DC
`POWER
`SUPPLY
`
`LAM Exh 1005-pg 1
`
`

`
`US. Patent
`
`Nov. 12, 1991
`
`Sheet 1 of 3
`
`5,065,118
`
`r 2‘ ‘*3
`
`Flgure 1/45 29'
`;\ A A n n
`
`41
`
`22
`)
`
`SOURCE
`
`1%: <
`
`LOAD
`
`34 <.
`46/-\<_____.>
`<-—--:
`42
`<"'",
`\/<""'>
`<I??m>
`
`<
`31 V r
`39 17$
`
`32
`
`30
`
`43
`1
`DC
`POWER
`SUPPLY
`
`44 x
`
`DC
`POWER
`SUPPLY
`
`1
`RF
`POWER j
`SUPPLY
`
`( 7
`
`13
`
`14
`J 9
`é
`
`~
`
`_. _ _ _ __
`
`8
`
`10
`
`T
`l
`|
`
`'
`
`r1
`11
`:
`
`12
`
`F
`
`l
`
`|
`
`l
`
`I
`
`6
`
`C
`,_
`
`PLASMA
`CHAMBER
`
`---
`
`\
`
`1
`2
`
`I
`Flgure 2 k 4
`
`3
`
`LAM Exh 1005-pg 2
`
`

`
`US. Patent
`
`Nov. 12, 1991
`
`Sheet 2 of 3
`
`5,065,118
`
`Figurs 3
`
`50
`
`59
`
`49
`
`Figure 4
`
`LAM Exh 1005-pg 3
`
`

`
`US. Patent
`
`Nov.12, 1991
`
`Sheet 3 of 3
`
`5,065,118
`
`wmm J
`
`@ 939m
`
`f1
`
`93.. a 1 558
`mi
`
`N2 N K % 5
`
`N \ 8m 8%? m2 :8
`\ \1
`3 N2 :2
`
`
`
`womm NoN Pom M mmm J
`
`N2 é m mSmE
`
`WUEDOw
`
`Pmm
`H
`
`LAM Exh 1005-pg 4
`
`

`
`1
`
`ELECI'RONICALLY TUNED VHF/UHF
`MATCHING NETWORK
`
`5,065,118
`
`2
`power which is due to dithering of the ?rst variable
`impedance element from the change in re?ected power
`which is due to dithering of the second variable impe
`dance element. Using the components of change, the
`control circuit continuously varies the steady state im
`pedance of the ?rst variable impedance and the steady
`state impedance of the second variable impedance in
`directions which minimize the reflected power. The
`dithered method of tuning and control always con
`verges to a unique matching solution, even for non-lin
`ear, dynamic loads. Convergence can be very fast by
`using high dither frequencies and magnetic dithering.
`The use of saturable reactors allows the variance of
`matching network impedance elements quickly and
`without moving parts.
`While the matching network discussed in US. Pat.
`No. 4,951,009 works well for signals in the radio fre
`quency range (frequency less than or equal to 30 Mega
`hertz), for high power signals in the very high fre
`quency (VHF) range (30-300 megahertz) or in the ultra
`high frequency (UHF) range (300-3000 megahertz),
`parasitic irnpedances within the magnetically saturable
`reactors are sufficiently large to cause non-ideal opera
`tional characteristics.
`One alternate approach for matching networks which
`handle high power signals in the VHF or UHF range is
`to use a distributed parameter approach. In the distrib
`uted parameter approach transmission line sections or
`stubs are used to match irnpedances. In the prior art, the
`impedance of each transmission line stub may be varied
`by mechanically moving a short circuit or tap which is
`connected to the transmission line stub. However, when
`it is desired to quickly change impedances of a matching
`network, for example in a dithering process, such me
`chanical movement is unacceptably slow and unreli
`able.
`
`SUMMARY OF THE INVENTION
`In accordance with the preferred embodiment of the
`present invention, a matching network is presented. The
`matching network matches an output impedance of a
`source with an input impedance of a load. The matching
`network includes a plurality of transmission line stubs.
`Each transmission line stub includes a ?rst transmission
`line conductor, a second transmission line conductor
`running parallel to but not in electrical contact with the
`?rst transmission line conductor, and ferrite dielectric
`material between the ?rst transmission line conductor
`and the second transmission line conductor. A magnetic
`?eld is used to vary the relative permeability of the
`ferrite dielectric material. Throughout the discussion of
`the present invention, the term ferrite dielectric mate
`rial means ferromagnetic or antiferromagnetic dielec
`tric material.
`In the preferred embodiment of the present invention
`the ?rst transmission line conductor and the second
`transmission line are coaxial. These may be imple
`mented by electrically conducting pipes placed one
`inside the other. Deionized water may be ?owed
`through the inner pipe to remove heat generated by the
`transmission line stub. Alternately, some other fluid,
`such as air, may be ?owed through the inner pipe to
`remove heat generated by the transmission line stub.
`Similarly air (or some other fluid such as deionized
`water) may be ?owed on the outside of the outer elec
`trically conducting pipe.
`
`20
`
`25
`
`BACKGROUND
`The present invention concerns the connection of a
`?rst electrical circuit to a second electrical circuit using
`a matching network so as to provide maximum power
`transfer between the first electrical circuit (the
`“source”) and second electrical circuit (the “load”).
`Maximum power is transferred from the source to the
`load when the output impedance of the source is the
`complex conjugate of the input impedance of the load.
`In most cases the output impedance of the source is not
`naturally equal to the complex conjugate of the input
`impedance of the load; therefore, matching networks
`are placed between the source and load when power
`control and efficiency are critical. A matching network
`operates properly when the input impedance of the
`matching network is the complex conjugate of the out
`put impedance of the source, and the output impedance
`of the matching network is the complex conjugate of
`the input impedance of the load. In this way power may
`be transferred from a source through a matching net
`work to a load with minimal loss of power through
`power reflection, heat dissipation, etc.
`In cases where the input impedance of the load varies
`during operation it is necessary to make adjustments to
`the matching network to maintain maximum power
`transfer from the source to the load. Typically, match
`ing networks are designed such that variations in the
`input impedance of the load will result in a variation of
`the impedance of the matching network, the input irnpe
`dance of the matching network being held constant.
`Further, in many applications the output impedance of
`35
`a source is an output resistance with a negligible imagi
`nary component. Therefore, in some prior art applica
`tions, the impedance magnitude and the impedance
`phase angle is measured at the input of the matching
`networks. Variable capacitors or inductors within the
`matching network are varied until the input impedance
`of the matching network matches the output impedance
`of the source network, that is until the impedance phase
`angle is zero and the impedance magnitude matches the
`magnitude of the output resistance of the source. The
`45
`variable capacitors or inductors are placed in the
`matching network so that for every predicted variance
`in the input impedance of the load there is a solution in
`which the variable capacitors are set to values so that
`for the input of the matching network the impedance
`phase angle is zero and the impedance magnitude
`matches the magnitude of the output resistance of the
`source.
`In US. Pat. No. 4,951,009 by Kenneth Collins et al.,
`entitled “Turning Method and Control System for Au
`tomatic Matching Network”, techniques are discussed
`in which variable impedance elements are used to re
`place variable capacitors and variable inductors. The
`variable impedance elements are constructed using
`magnetically saturable reactors, such as a transformer
`60
`composed of primary and secondary windings wound
`around a non-linear ferromagnetic core.
`Re?ective power is removed by “dithering”. What is
`meant by dithering is varying at a known-frequency or
`frequencies the impedance through the ?rst variable
`impedance element and the impedance through the
`second variable impedance element. A control circuit
`separates out the component of the change in reflected
`
`40
`
`50
`
`55
`
`65
`
`LAM Exh 1005-pg 5
`
`

`
`20
`
`25
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 shows an electronically tuned VHF/UHF
`matching network in accordance with the preferred
`embodiment of the present invention.
`FIG. 2 shows a electronically tuned matching net
`work as shown in FIG. 1 used in a system which
`supplies power to a plasma process in accordance with
`the preferred embodiment of the present invention.
`FIG. 3 and FIG. 4 show cross-sectional views of a
`design implementation of an electronically tuned
`matching network as shown in FIG. 2 in accordance
`with the preferred embodiment of the present inven
`tion.
`FIG. 5 shows an electronically tuned VHF/UHF
`35
`matching network in accordance with an alternate pre
`ferred embodiment of the present invention.
`FIG. 6 shows an electronically tuned VHF/UHF
`matching network in accordance with another alternate
`preferred embodiment of the present invention.
`
`30
`
`5,065,118
`4
`3
`Transmission line stub 46 consists of a transmission
`The transmission line stubs may be organized in a
`variety of topologies. For example, a ?rst transmission
`line conductor 31 and a transmission line conductor 32
`separated by a ferrite dielectric material. A magnetic
`line stub may extend from the source to the load. A
`?eld is applied to transmission line stub 46 by a current
`second transmission line stub may have one end con
`supplied by DC power supply 43 through a wire 42
`nected to the source and the other end terminated. Al
`wrapped around transmission line stub 46. Varying the
`ternately, two or more transmission line stubs may be
`current through wire 42, and thus the magnetic ?eld
`connected in series between the source and the load.
`applied to transmission line stub 46, varies the relative
`Another topology is to connect the source directly to
`permeability of transmission line stub 46. A terminator
`the load and connect a ?rst end of one or more transmis
`39 of transmission line stub 46 may be, for example, a
`sion line stubs to the connection between the source and
`the load. The unconnected end of each transmission line
`short circuit, an open circuit or some other circuit with
`a predetermined admittance. The admittance of termi
`stub would be terminated by a short circuit, open cir
`nator 39 is herein referred to as termination admittance.
`cuit, or other circuit of known admittance.
`A matching network designed according to the pre
`For the purpose of calculating the input admittance, the
`termination admittance of terminator stub 45 is the ad
`ferred embodiment of the present invention may be
`mittance of load 22. Also, throughout the following
`tuned by minimizing phase and magnitude errors, as
`described herein, or may be tuned by minimizing the
`discussion, values are given in terms of admittance,
`rather than its inverse (impedance), in order to simplify
`power re?ected from the input of the matching network
`the formulas used in the discussion.
`toward the source, as in the dithering technique de
`The matching network is adjusted so that admittance
`scribed in U.S. Pat. No. 4,951,009, referenced above.
`(Y ,-,,) between a line 33 and a line 34 of the matching
`network is equal to the output admittance (Y 8) of source
`21. This may be done in two steps. In the ?rst step, the
`magnetic ?eld applied to transmission stub 45 is varied
`so that the admittance of transmission stub 45 between
`line 33 and 34 is equal to Yg+/—jB, where B is a con
`stant and j is the imaginary number (— 1)l. In the second
`step, the magnetic ?eld applied to transmission stub 46
`is varied so that the admittance of transmission stub 46
`between line 33 and 34 is equal to -/+jB. Thus the
`admittance of transmission stub 46 cancels out the imag
`inary component of the admittance of transmission line
`stub 45 and leaves the total admittance of the matching
`network to be Y8.
`FIG. 2 shows a matching network of the type shown
`in FIG. 1 applied to a system which is used in a plasma
`process inside a plasma chamber 2. The load of the
`system is generated by the voltage across an electrode 5
`and walls 7 of plasma chamber 2, which act as a separate
`electrode. A capacitor 6, typically between 10 and 100
`picofarads isolates a dc voltage component on electrode
`5 from the matching network. The matching network
`matches the output admittance between a line 13 and a
`line 14 of a power supply 1. A ?rst transmission line stub
`of the matching network includes a coaxial transmission
`line conductor 9 enclosed by a coaxial transmission line
`conductor 8. A second transmission line stub of the
`matching network includes a coaxial transmission line
`conductor 11 enclosed by a coaxial transmission line
`conductor 10. As shown in FIG. 2, coaxial transmission
`line conductor 9 is electrically connected to capacitor 6,
`coaxial transmission line conductor 11 and line 13 of
`power supply 1. Also, coaxial transmission line conduc
`tor 8 is shown electrically connected to coaxial trans
`mission line conductor 10, line 14 of power supply 1,
`and walls 7 of plasma chamber 2. A short circuit, such
`as a disk 12, is used to electrically connect coaxial trans
`mission line conductor 11 to coaxial transmission line
`conductor 10 as shown. A vacuum pump 3 is used to
`pump out gasses within plasma chamber 2 through a
`conduit 4.
`FIG. 3 shows a cross-sectional side view of a possible
`implementation of the matching network shown in
`FIG. 2. Coaxial transmission line conductor 9 may be
`implemented using a copper tube 49 having an outside
`radius of approximately 0.0095 meters and a length as
`calculated below. Coaxial transmission line conductor 8
`may be implemented using a copper pipe 50 having an
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENT
`In FIG. 1, a source 21 is shown connected to a load
`22 through an electronically tuned VHF/UHF match~
`ing network. The electronically tuned VHF/UHF
`matching network consists of a transmission line stub 45
`and a transmission line stub 46, arranged in the shown
`topology.
`Transmission line stub 45, in general, may be of any
`transmission line type with two conductors separated
`by a ferrite dielectric material. Throughout the discus
`sion of the present invention, the term ferrite dielectric
`material means ferromagnetic or antiferromagnetic di
`electric material. For example transmission line stub 45
`may be twin leads with a ferrite dielectric material be
`tween each of the twin leads. Alternately transmission
`line stub 45 may be coaxial.
`In FIG. 1, transmission line stub 45 is shown to con
`sist of a transmission line conductor 29 and a transmis
`sion line conductor 30 separated by a ferrite dielectric
`material. A magnetic ?eld is applied to transmission line
`stub 45 by a current supplied by DC power supply 44
`through a wire 41 wrapped around transmission line
`stub 45. Varying the current through wire 41, and thus
`the magnetic ?eld applied to transmission line stub 45,
`varies the relative permeability of transmission line stub
`45.
`
`50
`
`55
`
`60
`
`65
`
`LAM Exh 1005-pg 6
`
`

`
`6
`ro=radius of the outer conductor (meters)
`ri=radius of the inner conductor (meters).
`Once the characteristic admittance of the transmis
`sion line stub is calculated, the input admittance of the
`transmission line stub (Y in) may be calculated using the
`following formula:
`
`5
`
`10
`
`where:
`,= termination admittance of the transmission line
`stub (Siemens)
`
`5,065,118
`5
`inside radius of approximately 0.0159 meters and a
`length as calculated below. A ferrite dielectric 53 is
`placed between copper tube 49 and copper pipe 50.
`Ferrite dielectric 53 may be for example, a plurality of
`ferrite toroidal cores, available as part number M3-665
`from National Magnetics Group, Inc. having a business
`address of 250 South Street, Newark, NJ. 07114. A
`magnetic ?eld, used to vary the relative permeability of
`ferrite dielectric 53, is generated by current through a
`solenoid coil 55 wrapped around copper pipe 50 as
`shown. Solenoid coil 55 is made of, for example,
`enamel, insulated, tightly wove 8 AWG copper wire.
`During operation the transmission stub is cooled by
`deionized water ?owing within a center region 59 of
`copper tube 49, and by air ?ow through an open region
`57 between copper pipe 50 and solenoid coil 55. While
`solenoid coil 55 may be placed directly upon copper
`pipe 50, in the preferred embodiment open region 57
`exists to allow ?uid to pass between solenoid coil 55 and
`copper pipe 50.
`Coaxial transmission line conductor 11 may be imple
`mented using a copper tube 51 having an outer radius of
`approximately 0.0095 meters and a length as calculated
`below. Coaxial transmission line conductor 10 may be
`implemented using a copper pipe 52 having a inner
`radius of approximately 0.0195 meters and a length as
`calculated below. A ferrite dielectric 54 is placed be
`tween copper tube 51 and copper pipe 52. Ferrite di
`electric 54 may be for example, a plurality of ferrite
`toroidal cores, available as part number M3-665 from
`National Magnetics Group, Inc. having the business
`address given above. A magnetic ?eld, used to vary the
`relative permeability of ferrite dielectric 54, is gener
`ated by current through a solenoid coil 56 wrapped
`around copper pipe 52 as shown. Solenoid coil 56 is
`made of, for example, tightly enamel, insulated wove 8
`AWG copper wire. During operation the transmission
`stub is cooled by deionized water (or some other ?uid
`such as air) ?owing within a center region 60 of copper
`tube 51, and by air ?ow (or the flow of some other ?uid
`such as deionized water) through an open region 58
`between copper pipe 52 and solenoid coil 56. While
`solenoid coil 56 may be placed directly upon copper
`pipe 52, in the preferred embodiment open region 58
`exists to allow ?uid to pass between solenoid coil 56 and
`copper pipe 52.
`FIG. 4 shows another cross-sectional front view of
`the matching network shown in FIG. 3. The cross-sec
`tional view shown in FIG. 4 is along an axis perpendicu
`lar to the axis of the cross-sectional view shown in FIG.
`3.
`In general, for each of the transmission line stubs
`shown in FIG. 3, the characteristic admittance of the
`transmission line (Y 0) may be calculated by the follow
`ing formula:
`
`20
`
`25
`
`30
`
`35
`
`45
`
`50
`
`55
`
`d=length of the transmission line stub (meters)
`7t=free space wavelength of the signal through the
`transmission line stub (c/f) (meters)
`c=free space speed of light (300>< 106 meters/
`second)
`f =frequency of oscillation of the signal through the
`transmission line stub (Hertz).
`A three step formula may be used in the designing of
`a matching network such as that shown in FIG. 3. In the
`?rst step, ferrite dielectric material for constructing
`ferrite dielectric 53 and ferrite dielectric 54 is chosen. In
`selecting the ferrite dielectric material it is important to
`select material which will have a low loss and a high
`relative permeability in the operating frequency range
`of the matching network. Solenoid coil 55 and solenoid
`coil 56 will respectively vary ferrite dielectric 53 and
`ferrite dielectric 54 between a minimum relative perme
`ability (pmin) and a maximum relative permeability
`(Puma)
`In the second step, the length of copper tube 49 and
`copper pipe 50 of the first transmission line stub is deter
`mined by iteration so that the real component of Y,-,, of
`the ?rst transmission line stub may be made equal to Y8
`over the range solenoid coil 55 varies the relative per
`meability of ferrite dielectric 53. Then the length of
`copper tube 51 and copper pipe 52 of the second trans
`mission line stub is determined by iteration so that the
`imaginary component of Yin of the ?rst transmission line
`stub may be canceled over the range solenoid coil 56
`varies the relative permeability of ferrite dielectric 54.
`When making the iterative determination of the
`length (d1) of the ?rst transmission line stub a good ?rst
`guess is three fourths the wavelength of the signal
`through the ?rst transmission line stub when the rela
`tive permeability of ferrite dielectric 53 is at its maxi
`mum value. That is when:
`
`d] = 30¢ (611m)‘) (meters)
`
`When making the iterative determination of the
`length (d;) of the second transmission line stub a good
`?rst guess is one half the wavelength of the signal
`through the second transmission line stub when the
`relative permeability of ferrite dielectric 54 is at its
`maximum value. That is when:
`
`where:
`po=permeability of free space (41rX 10-7 Henry/m
`eter).
`p.=relative permeability of the ferrite dielectric be
`tween the inner and the outer conductors.
`¢0=permittivity of free space (8.86 X10‘12 Farad/m
`eter)
`e=relative permittivity of the ferrite dielectric be
`tween the inner and the outer conductors (dielec
`tric constant).
`
`65
`
`In the third step, the number of turns of solenoid coil
`55, the number of turns of solenoid coil 56, the maxi
`mum current through solenoid coil 55 and the maximum
`current through solenoid coil 56 is determined so that a
`magnetic ?eld of suf?cient strength may be generated
`
`LAM Exh 1005-pg 7
`
`

`
`5,065,118
`7
`8
`to reach the desired minimum relative permeability of
`Applicant’s invention may be applied to a variety of
`matching network topologies. For example, in FIG. 5, a
`ferrite dielectric 53 and ferrite dielectric 54.
`matching network, consisting of a transmission line stub
`What follows is an example of the design of a typical
`system in which Yg=0.02 Siemens, the maximum signal
`101 and a transmission line stub 102 connected in paral
`frequency is 100 megahertz and the load admittance has
`lel, is shown between a source 121 and a load 122.
`Transmission line stub 101 includes a transmission line
`a real component only which varies from 0.05 Siemens
`conductor 131, a transmission line conductor 132 and a
`to 0.5 Siemens. For both the ?rst transmission line stub
`terminator 133. Transmission line stub 102 includes a
`and the second transmission line stub r,, is selected to be
`transmission line conductor 129, a transmission line
`0.0159 meters; and r; is selected to be 0.095 meters.
`conductor 130 and a terminator 128. A transmission line
`Ferrite dielectric 53 and ferrite dielectric 54 are se
`135 connects source 121 to load 122.
`lected to be made from a plurality of ferrite toroidal
`For best operation of the two stub system shown in
`cores, available as part number M3-665 from National
`FIG. 5, the part of transmission line extending from
`Magnetics Group, Inc. This material has a maximum
`source 121 to the connection of stub 101 should have a
`permeability (pm) of 20 when there is no magnetic
`characteristic admittance equal to the output admit
`field applied to it and a minimum permeability (p.,.,-,,) of
`tance of the source. Further, for best tuning range, the .
`5 when an external magnetic ?ux density (B) of 1000
`length of transmission line 135 measured from the con
`gauss is applied.
`nection of stub 101 to the connection of stub 102 should
`The length of the ?rst transmission line stub is chosen
`be three-eighths of a wavelength of the signal generated
`to be three-fourths the wavelength of the signal through
`by source 121, and the length of transmission line 135
`the ?rst transmission line stub when the relative perme
`measured from the connection of stub 102 to load 122
`ability of ferrite dielectric 53 is at its maximum value
`should be three-eighths of a wavelength of the signal
`(p,m=20), in this case the length equals 0.185 meters.
`generated by source 121.
`A check is made to see that at the maximum fre
`Alternatively, in FIG. 6, a matching network, con
`quency (100 megahertz) and for the range of variation
`sisting of a transmission line stub 201 and a transmission
`of load admittance, permeability of ferrite dielectric 53
`line stub 202 connected in series, is shown between a
`may be varied between pm, (20) and 1.1mm (5) to gener
`source 221 and a load 222. Transmission line stub 201
`ate a real component of Yin of the ?rst transmission line
`includes a transmission line conductor 231 and a trans
`stub that equals Yg (0.02 Siemens). The check veri?es
`mission line conductor 232. Transmission line stub 202
`that the length is acceptable because at the minimum
`includes a transmission line conductor 229 and a trans
`load admittance of 0.05 Siemens, when permeability (u)
`mission line conductor 230.
`of ferrite dielectric 53 is 13.5, Y,-,, equals 0.019- j(0.0l5);
`We claim:
`and, at the maximum load admittance of 0.5 Siemens,
`1. A transmission line stub in a matching network
`when permeability (u) of ferrite dielectric 53 is 10.3,
`coupled between a power supply and electrodes used in
`Yin cquals 0.019- j(0.092).
`a plasma process, the transmission line stub comprising:
`Next, the length of the second transmission line stub
`a ?rst electrically conducting pipe;
`is chosen to be one-half the wavelength of the signal
`a second electrically conducting pipe, the second
`through the second transmission line stub when the
`electrically conducting pipe being placed inside the
`relative permeability of ferrite dielectric 54 is at its
`?rst electrically conducting pipe;
`maximum value (pmax=20), in this case the length
`ferrite dielectric material between the ?rst electri
`equals 0.125 meters.
`cally conducting pipe and the second electrically
`A check is made to see that at the maximum fre
`conducting pipe, the ferrite dielectric material
`quency (100 megahertz) and for the range of variation
`being in thermal contact with the ?rst electrically
`of load admittance, permeability of ferrite dielectric 54
`conducting pipe and the second electrically con
`may be varied between pm“ (20) and p.,,,,-,, (5) to gener
`ducting pipe;
`45
`ate an imaginary component of Y,-,, of the second trans
`variance means for changing the relative permeabil
`mission line stub that cancels out the imaginary compo
`ity of the ferrite dielectric material; and,
`nent of Y,-,I of the ?rst transmission line. The check
`cooling means for cooling the second electrically
`veri?es that the length is acceptable. The imaginary
`conducting pipe and the ferrite dielectric material,
`component of Y,-,I of the ?rst transmission line varies
`the cooling means including fluid ?owing through
`between -j(0.0l5) when the load admittance is 0.05
`the second electrically conducting pipe.
`Siemens and —j(0.092) when the load admittance is 0.5
`2. A transmission line stub as in claim 1, wherein the
`Siemens. This range is covered. Speci?cally, when per
`?uid ?owing though the second electrically conducting
`meability (a) of ferrite dielectric 54 is 7.0, Yi,I of the
`pipe is deionized water.
`second transmission line is +j(0.0l2). Similarly, when
`3. A transmission line stub as in claim 1 wherein the
`55
`permeability (p) of ferrite dielectric 54 is 16.5, Y,-,, of the
`variance means includes a magnetic ?eld generator
`second transmission line is +j(0.l03). Thus the chosen
`which comprises:
`lengths of the ?rst transmission line stub and the second
`wire wrapped around the ?rst electrically conducting
`transmission line stub are acceptable.
`pipe, the second electrically conducting pipe and
`In order to generate a magnetic flux density of 1000
`the ferrite dielectric material; and,
`gauss when r,, is 0.0159 meters and r,- is 0.095 meters,
`a current generating means for generating current
`solenoid coil 55 and solenoid coil 56 are required to
`through the wire.
`produce a maximum magnetic ?eld intensity (H) of
`4. A transmission line stub as in claim 3 additionally
`96,000 amperes-turns per meter. This may be accom
`comprising ?ow means for ?owing ?uid between the
`plished, for example, by setting current through sole
`wire and the ?rst electrically conducting pipe.
`65
`noid coil 55 and solenoid coil 56 to have a maximum
`5. A transmission line stub as in claim 4 wherein the
`value of 4-0 amperes, and constructing solenoid coil 55
`?uid ?owing between the wire and the ?rst electrically
`conducting pipe is air.
`and solenoid coil 56 to have 2400 turns per meter.
`
`35
`
`LAM Exh 1005-pg 8
`
`

`
`5,065,118
`9
`6. A matching network with a plurality of transmis
`sion line stubs, the matching network being coupled
`between a power supply and electrodes used in a plasma
`process, wherein each transmission line stub comprises:
`a ?rst electrically conducting pipe;
`a second electrically conducting pipe, the second
`electrically conducting pipe being placed inside the
`?rst electrically conducting pipe;
`ferrite dielectric material between the ?rst electri
`cally conducting pipe and the second electrically
`conducting pipe;
`variance means for changing the relative permeabil
`ity of the ferrite dielectric material; and,
`cooling means for cooling the second electrically
`conducting pipe and the ferrite dielectric material,
`the cooling means including ?uid ?owing through
`the second electrically conducting pipe.
`7. A matching network as in claim 6 wherein the
`variance means includes a magnetic ?eld generator
`which comprises:
`wire wrapped around the ?rst electrically conducting
`pipe, the second electrically conducting pipe and
`the ferrite dielectric material; and,
`current generating means for generating current
`through the wire.
`8. A matching network as in claim 6 wherein wherein
`a ?rst transmission line stub from the plurality of trans
`mission line stubs is coupled between the power supply
`and the the electrodes, and wherein a ?rst end of a
`second transmission line stub from the plurality of trans
`mission line stubs is coupled to the power supply and a
`second end of the second transmission line stub is cou
`pled to a terminator.
`9. A matching network as in claim 8 wherein the
`terminator is a short circuit electrically coupling a ?rst
`electrically conducting pipe of the second transmission
`line stub to a second electrically conducting pipe of the
`second transmission line stub.
`10. A matching network as in claim 6 wherein a ?rst
`transmission line stub from the plurality of transmission
`line stubs and a second transmission line stub from the
`plurality of transmission line stubs are coupled in series
`between the power supply and the the electrodes.
`11. A matching network as in claim 6 wherein a ?rst
`end of a ?rst transmission line stub from the plurality of 45
`transmission line stubs is coupled to a connecting trans
`mission line connecting the power supply to the the
`electrodes, and a second end of the ?rst transmission
`line stub is coupled to a ?rst terminator, and wherein a
`?rst end of a second transmission line stub from the
`plurality of transmission line stubs is coupled to the
`connecting transmission line and a second end of the
`
`10
`second transmission line stub is coupled to a second
`terminator.
`12. A matching network as in claim 6, wherein the
`?uid ?owing through the second electrically conduct
`ing pipe is deionized water.
`13. A matching network as in claim 6 wherein each
`transmission line stub additionally comprises ?ow
`means for ?owing ?uid between the wire and the ?rst
`electrically conducting pipe.
`14. A matching network as in claim 13 wherein the
`?uid ?owing between the wire and the ?rst electrically
`conducting pipe is