United States Patent (19)
`Gorin
`
`11
`45
`
`Patent Number:
`Date of Patent:
`
`4,464,223
`Aug. 7, 1984
`
`54)
`
`75
`(73)
`21)
`22
`(51)
`52
`58
`
`PLASMA REACTOR APPARATUS AND
`METHOD
`Inventor: Georges J. Gorin, Pinole, Calif.
`Assignee: Tegal Corp., Novato, Calif.
`Appl. No.: 538,593
`Filed:
`Oct. 3, 1983
`Int. Cl....................... H01L 21/312; B44C 1/22;
`CO3C 15/00; C23F 1/02
`U.S. C. .................................... 156/643; 156/646;
`156/345; 204/192 E; 204/298
`Field of Search ................... 204/298, 192 E, 164:
`156/643, 646, 345, 657, 656, 659.1, 662, 665;
`427/38, 39
`
`56
`
`References Cited
`U.S. PATENT DOCUMENTS
`4,233,109 11/1980 Nishizawa ....................... 156/345 X
`4,349,409 9/1982 Shibayama et al. ................ 156/643
`
`4,352,725 10/1982 Tsukada .......................... 204/192 E
`4,399,016 8/1983 Tsukada et al. ................ 204/192 R
`Primary Examiner-William A. Powell
`57
`ABSTRACT
`An improved plasma reactor apparatus and method are
`disclosed. Improved uniformity of etching and etch rate
`are achieved in a reactor through the use of electrodes
`powered at high and low frequencies. In one embodi
`ment of the invention the workpiece which is to be
`etched rests on an electrode powered at a low AC fre
`quency of about 100 KHz. A second electrode is pow
`ered at a high AC frequency of about 13.56 MHz. A
`third electrode is maintained at ground potential. High
`and low frequency AC fields acting on a reactant mate
`rial optimize the dissociation of the reactant material
`and the ion energy of the plasma generated reactant
`species.
`
`11 Claims, 4 Drawing Figures
`
`COMMON
`GROUND
`
`
`
`SO
`
`3.56 MHz
`POWER SUPPLY
`
`
`
`100 KHz
`POWER SUPPLY
`
`35
`
`
`
`
`
`
`
`
`
`TUNEAT
`13.56 MHz
`
`DC SUPPLY
`
`POWER
`METER
`
`42
`
`Samsung Electronics Co., Ltd. v. Demaray LLC
`Samsung Electronic's Exhibit 1009
`Exhibit 1009, Page 1
`
`

`

`U.S. Patent Aug. 7, 1984
`
`Sheet 1 of 2
`
`4,464,223
`
`5
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`
`Ex. 1009, Page 2
`
`

`

`U.S. Patent
`
`Aug. 7, 1984
`
`Sheet 2 of 2
`
`4,464,223
`
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`Ex. 1009, Page 3
`
`Ex. 1009, Page 3
`
`
`
`
`
`

`

`1
`
`PLASMA REACTORAPPARATUS AND METHOD
`
`5
`
`15
`
`BACKGROUND OF THE INVENTION
`This invention relates to an improved plasma reactor
`apparatus and method, and more specifically to a multi
`ple frequency plasma reactor apparatus and to a method
`for etching workpieces within that apparatus.
`Plasma etching and reactive ion etching (RIE) have
`10
`become important processes in the precision etching of
`certain workpieces such as in the fabrication of semi
`conductor devices. Differences in the two processes,
`which generally can be carried out in the same equip
`ment, result from different pressure ranges employed
`and from the consequent differences in mean free path
`of excited reactant species. The two processes will
`herein be referred to collectively as plasma etching.
`Plasma etching is a "dry etching' technique and has a
`number of advantages over conventional wet etching in
`20
`which the workpiece is generally immersed in a con
`tainer of liquid etchant material. Some of the advan
`tages include lower cost, reduced pollution problems,
`reduced contact with dangerous chemicals, increased
`dimensional control, increased uniformity, improved
`25
`etch selectivity, and increased process flexibility. In
`existing plasma etch systems, however, it has not gener
`ally been possible to simultaneously achieve all of these
`advantages. A need therefore existed for equipment and
`process which would make several of the foregoing
`30
`advantages simultaneously attainable.
`It is therefore an object of this invention to provide
`an improved plasma reactor apparatus.
`It is another object of this invention to provide an
`improved plasma etch process which enhances process
`flexibility.
`It is another object of this invention to provide an
`improved plasma process which provides a higher de
`gree of control over ion density and ion energy than
`previously practical.
`It is a still further object of this invention to provide
`an improved plasma reactor apparatus, and a process
`for practice in that apparatus, which provides an im
`proved uniformity of etch, improved etch selectivity,
`and improved dimensional control.
`BRIEF SUMMARY OF THE INVENTION
`The foregoing and other objects and advantages are
`achieved in the present invention through the use of a
`multiple frequency plasma reactor apparatus. The
`50
`plasma reactor apparatus includes three electrodes. One
`of the electrodes is held at ground while the second is
`selectively coupled to a high frequency AC source and
`the third is selectively coupled to a low frequency AC
`source. A plasma generated by the high and/or low
`55
`frequency electric fields established between the elec
`trodes creates excited species of the reactants injected
`into the apparatus. The excited species act to precisely
`etch a workpiece positioned within the reactor.
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 illustrates percentage dissociation and ion
`energy as a function of plasma frequency;
`FIG. 2 illustrates in cross section one embodiment of
`plasma apparatus in accordance with the invention;
`65
`FIG. 3 schematically illustrates a second embodiment
`of plasma apparatus in accordance with the invention;
`and
`
`4,464,223
`2
`FIG. 4 illustrates coupling of the electrodes and
`power supplies of the second embodiment of the appa
`ratus.
`DETAILED DESCRIPTION OF PREFERRED
`EMBODIMENTS
`In the nomenclature associated with plasma reactors
`and plasma processes, it is common to describe as "high
`frequency' any frequency greater than about 10 MHz.
`"Low frequency" is correspondingly used to describe
`any frequency less than about 1 MHz. The frequency of
`RF power applied to a reactant gas has an appreciable
`effect on the plasma that is generated from that gas.
`FIG. 1 illustrates, for example, the effect of frequency
`on the amount of dissociation that occurs in the reactant
`gas making up the plasma. The dissociation remains low
`until the frequency exceeds about 10 MHz. FIG. 1 also
`illustrates the effect of frequency on the energy of the
`ions generated in the plasma. The ion energy is gener
`ally high at low frequencies and falls off rapidly as the
`frequency is increased. The amount of dissociation of
`the reactant gas and the energy of the ions within the
`plasma have a marked effect on the uniformity of etch
`ing and also upon the rate of etching. The uniformity of
`etch is a strong function of the high frequency power
`while etch rate, for example in the case of oxide etching,
`is a strong function of low frequency power.
`A high degree of etch uniformity and a high etch rate
`are achieved, in accordance with the invention, through
`the use of a plasma reactor apparatus employing three
`electrodes in combination with both a high frequency
`power source and a low frequency power source. One
`embodiment of apparatus in accordance with the inven
`tion is illustrated in cross section in FIG.2. The appara
`tus includes a first electrode 10, a second electrode 12,
`and a third electrode 14. The first and third electrodes
`are generally circular and the second electrode is ring
`shaped. Ring-shaped ceramic insulators 16 and 18 pro
`vide electrical isolation between the first and second
`and the second and third electrodes, respectively. To
`gether the three electrodes and two ceramic rings
`bound a generally cylindrical reaction volume 20. Al
`though not shown, the electrodes can be provided with
`temperature control means such as water cooling.
`A gas inlet 22 provides for the ingress of reactants to
`the reaction volume. A gas outlet 24 provides for the
`egress of reaction products from the reaction volume
`under the influence of a vacuum pump (not shown). A
`top plate 26 and a clamp ring 28 mechanically hold the
`plasma reactor components together.
`Lower electrode 14 is adapted for movement in the
`vertical direction. The electrode can be lowered to
`open the apparatus and to allow the placement of a
`workpiece within reaction volume 20. The workpiece
`can be placed directly on the electrode, which functions
`as a workpiece holder, and then the electrode raised to
`the closed position.
`In accordance with the invention, a high frequency
`power supply 30 and a low frequency power supply 36
`are coupled to the second and third electrodes, respec
`tively, so that high and low frequency electric fields can
`be established within the reaction volume to act upon
`reaction gases which enter the reactor through inlet 22.
`In a preferred embodiment of the invention the top
`electrode 10 is coupled to ground. This electrode func
`tions as the common ground for the system, being the
`ground reference for DC as well as high and low fre
`quency AC supplies. The second electrode, the cylin
`
`35
`
`45
`
`Ex. 1009, Page 4
`
`

`

`4,464,223
`3
`4.
`drical ring electrode 12, is coupled to a high frequency
`70 electrically isolate the three electrodes from each
`AC power supply 30 through a matching network 32.
`other.
`FIG. 4 schematically illustrates one way in which the
`Power, including both forward and reflected power, is
`three electrodes can be powered. A high frequency
`monitored on a power meter 34. Lower electrode 14 is
`coupled to a low frequency AC power supply 36
`power supply 72 such as a supply at 13.56 MHz is cou
`pled between electrodes 62 and 66. A low frequency
`through a matching network 38. Low frequency AC
`power supply 74, such as a supply having a frequency of
`power is monitored on a power meter 40. The high
`frequency power supply is preferably at a frequency of
`about 100 KHz is coupled between electrodes 64 and
`66. In addition, DC supplies 76 and 78 are coupled
`about 13.56 MHz (a frequency allocated for industrial
`between electrodes 62 and 64 and between electrodes 64
`uses by the FCC) and the low frequency power supply
`and 66, respectively. Each of the supplies can be turned
`is preferably at a frequency of about 100 KHz.
`on or off or adjusted in power to create the desired
`In one embodiment of the invention the lower elec
`plasma and to establish the desired DC bias on one or .
`trode is also coupled to a DC supply 42. Use of a DC
`more electrodes.
`power supply allows the amount of DC biasing induced
`The following are non-limiting examples which serve
`by the plasma to be changed, independently of pressure
`15
`to further illustrate practice of the invention and to
`or power.
`disclose preferred embodiments contemplated by the
`In a still further embodiment of the invention, a series
`inventor.
`circuit 44, including, for example, an inductor 46 and
`capacitor 48, tuned to the frequency of high frequency
`power supply 30, is coupled between lower electrode 14
`and ground. Switch 49 permits the selective coupling of
`series circuit 44 to electrode 14.
`During operation of the apparatus, in accordance
`with the invention, a workpiece, such as a semiconduc
`25
`tor wafer, is placed on electrode 14 and the reaction
`volume is evacuated to a desired low pressure. Reactant
`gases are then admitted to the reaction chamber and the
`power supplies are energized. Either one or both AC
`power supplies can be energized, with or without the
`30
`DC supply. Either AC supply creates a plasma within
`the reaction volume so that excited species of the reac
`tant gas are created. Energizing high frequency supply
`32 establishes an electric field which exists principally
`between upper electrode 10 and side electrode 12. Ener
`35
`gizing low frequency power supply 36 creates a low
`frequency field which exists principally between lower
`electrode 14 and upper electrode 10. The combination
`of the two fields within the reaction volume and in
`proximity to the workpiece located on the lower elec
`40
`trode causes maximum dissociation of the reaction gas
`as well as imparting a high ion energy to the ions within
`the plasma.
`The selective use of series circuit 44 by the closing of
`switch 49 has two effects. First, the tuned series circuit,
`45
`which effectively places the lower electrode 14 at
`ground with respect to the high frequency supply,
`changes the electrode area ratio between the high fre
`quency electrode and the ground electrode. This affects
`the plasma sheath potential above the wafer without
`physically changing the reactor. Second, coupling the
`series tank circuit to the lower electrode selectively
`couples the high frequency supply to the workpiece
`itself. This allows the optimizing of etch rates and etch
`selectivity for certain films. For example, the etch rate
`55
`of silicon is high at low frequencies and drops off rap
`idly at high frequencies. In contrast, aluminum etches
`only slowly at low frequencies but etches rapidly at
`high frequencies. Thus, by selectively turning on or off
`the low frequency power supply and by selectively
`60
`coupling or uncoupling the series circuit, the workpiece
`can be exposed to a high frequency, low frequency, or
`mixed frequency plasma.
`FIG. 3 schematically illustrates a further embodiment
`of the invention. In this embodiment a plasma reactor 60
`65
`includes a first top electrode 62, a screen electrode 64,
`and a bottom electrode 66. The bottom electrode can
`also function as a workpiece holder. Insulators 68 and
`
`EXAMPLE I
`A plurality of silicon wafers were thermally oxidized
`to grow a silicon dioxide layer about 500 nm in thick
`ness. Over the oxide layer was formed a layer of poly.
`crystalline silicon, heavily doped with phosphorous and
`having a thickness of about 500 nm. A patterned photo
`resist etch mask was then formed on the layer of poly
`crystalline silicon. The wafers were divided into groups
`for the patterned plasma etching of the polycrystalline
`layer in a reactor as illustrated in FIG. 2. The polycrys
`talline layer was first etched in a mixture of SF6 plus
`10% CCl3F. The pressure in the reactor was maintained
`at 0.25 torr. The AC power between the top and side
`electrodes was maintained at 100 watts CW at 13.56
`MHz. The polycrystalline silicon was etched until end
`point was detected, approximately 40 seconds. The
`polycrystalline silicon layer was then given an overetch
`in CCl3F for about 18 seconds. During the overetch the
`high frequency power was maintained at 100 watts. One
`group of wafers was overetched with an additional DC
`bias of 100-150 volts applied to the wafer support elec
`trode; one group was overetched without an additional
`DC bias. Wafers were examined after the etching.
`Those wafers overetched without a DC bias exhibited
`undercutting of the photoresist mask and a negative
`slope in the etched openings. That is, etched openings
`were narrower at the top of the polycrystalline silicon
`layer than at the bottom. Those wafers etched with a
`DC bias exhibited a decrease in undercutting and an
`increase in etched opening profile control. Additional
`groups of wafers were etched with a low frequency
`(100 KHz) supply coupled to the wafer support elec
`trode. The low frequency plasma increased the aniso
`trophy of the polycrystalline silicon etch, but the etch
`selectivity of polycrystalline silicon over silicon dioxide
`decreased.
`
`EXAMPLE II
`A plurality of silicon wafers were thermally oxidized
`to grow a 500 nm thick layer of silicon dioxide. A layer
`of aluminum plus 4% copper was applied over the sili
`con dioxide to a thickness of 1000 nm. A patterned
`photoresist mask was formed over the Al/Cu layer. The
`wafers were divided into two groups for the etching of
`the alumimum. Both groups were etched in a CCl4
`plasma at 0.2-0.3 torr in a reactor as illustrated in FIG.
`2. One group was etched using only a 13.56 MHz
`plasma with the high frequency plasma maintained at
`125 watts CW. The second group was etched using an
`
`10
`
`50
`
`Ex. 1009, Page 5
`
`

`

`5
`
`10
`
`15
`
`30
`
`35
`
`40
`
`4,464,223
`6
`5
`reactant gases, and applications of the invention. It is
`additional 100 KHz power supply maintained at 50-100
`intended that all such variations and modifications be
`watts CW. The Al/Cu film etched about 30% faster
`included within the appended claims.
`when using the two power supplies than when using the
`high frequency power supply alone. In addition, using
`I claim:
`1. A reactor apparatus including a reaction volume
`the two power supplies together resulted in a cleaner
`into which reactants are injected and from which reac
`resultant wafer with less residue than when using the
`high frequency supply alone.
`tion products are exhausted, and in which said reactants
`are acted upon by electric fields to form a plasma
`EXAMPLE III
`thereof, said apparatus comprising: first, second, and
`A number of silicon wafers were thermally oxidized
`third electrodes, said first electrode coupled to electri
`cal ground, said second electrode selectively coupled to
`to grow a 500 nm layer of silicon dioxide. A patterned
`a high frequency source of AC power, and said third
`photoresist mask was formed over the oxide layer. The
`electrode selectively coupled to a low frequency source
`oxide layer was pattern etched in a CF4 plasma at about
`of AC power.
`0.050 torr in a plasma apparatus as illustrated in FIG. 2.
`2. The reactor of claim 1 wherein said third electrode
`The wafers were divided into groups for etching. The
`is further coupled to a source of DC power.
`first group was etched in a high frequency plasma (13.56
`3. The reactor of claim 1 wherein said third electrode
`MHz, 200 watts). The etch rate of the oxide was mea
`is adapted for holding a workpiece.
`sured to be 9.5 nm per minute. The second group was
`4. The reactor of claim 3 wherein said third electrode
`etched in a low frequency plasma (100 KHz, 200 watts).
`is temperature controlled.
`The etch rate of the oxide in the low frequency plasma
`20
`5. The reactor of claim 3 wherein said third electrode
`was measured to be 93.7 nm per minute. The third
`group was etched in a high frequency/low frequency
`is water cooled.
`6. The reactor of claim 1 further comprising means
`plasma (13.56 MHz, 200 watts; 100 KHz, 200 watts).
`having a low impedance at the frequency of said high
`The etch rate was measured to be 122.7 nm per minute.
`frequency source selectively coupled between said third
`Additional groups were etched as above, but with a DC
`25
`electrode and electrical ground.
`bias of up to 500 volts applied to the wafer holder elec
`7. A plasma reactor apparatus comprising: first, sec
`trode to reduce the natural DC bias established by the
`ond, and third electrodes; a first insulator electrically
`plasma. The wafers etched with the additional DC bias
`separating said first and second electrodes; a second
`were found to have improved photoresist integrity and
`insulator electrically separating said second and third
`improved uniformity.
`electrodes; said electrodes and said insulators positioned
`EXAMPLE IV
`to bound a reaction volume; means for admitting reac
`tants to said reaction volume and for removing reaction
`Wafers were prepared and etched as in Example III
`products from said reaction volume; a first high fre
`except that the AC power supplies were pulsed, with
`quency AC power supply selectively coupled to said
`the high and low frequency power supplies operated
`second electrode; a second low frequency AC power
`alternately. One AC supply was operated for 1 msec.,
`supply selectively coupled to said third electrode; and
`AC power off for 0.2 m.sec., the other AC power supply
`an electrical ground coupled to said first electrode.
`was operated for 1 m.sec., AC power off for 0.2 msec.,
`8. A method for etching a workpiece positioned in a
`and so on. The etch rates of the oxide were nearly the
`plasma reactor apparatus which comprises the steps of:
`same as with continuously operated supplies and there
`providing first, second, and third electrodes in said
`was less attack of the photoresist. Very importantly,
`apparatus; injecting a reactant gas into said apparatus;
`harmonics were not generated as is possible when si
`and creating a reactant gas plasma by selectively apply
`multaneously operating the two AC supplies.
`ing a high frequency AC field between said first and
`Thus it is apparent that there has been provided, in
`second electrodes and a low frequency AC field be
`accordance with the invention, an improved plasma
`45
`tween said first and third electrodes.
`reactor apparatus and method which fully meet the
`9. The method of claim 8 further comprising the step
`objects and advantages set forth above. While the in
`applying a DC bias between said first and third elec
`vention has been described and illustrated with refer
`ence to specific embodiments thereof, it is not intended
`trodes.
`10. The method of claim 8 wherein said high fre
`that the invention be so limited. Those skilled in the art,
`quency and said low frequency AC fields are pulsed.
`after consideration of the foregoing description, will
`11. The method of claim 10 wherein said low fre
`recognize that many variations and modifications are
`quency and said high frequency AC fields are alter
`possible which still fall within the broad scope of the
`nately applied.
`invention. Such variations include the particular shape
`of the electrodes, positioning of gas inlets and outlets,
`
`k
`
`se
`
`k
`
`is
`
`sk
`
`50
`
`55
`
`60
`
`65
`
`Ex. 1009, Page 6
`
`

`

`REEXAMINATION CERTIFICATE (1447th)
`11 B1 4,464,223
`United States Patent (19)
`45 Certificate Issued
`Apr. 9, 1991
`Gorin
`
`(54) PLASMA REACTOR APPARATUS AND
`METHOD
`
`75) Inventor: Georges J. Gorin, Pinole, Calif.
`
`73 Assignee: Tegal Corp., Novato, Calif.
`Reexamination Reqsist:
`No. 90/001,809, Jul. 14, 1989
`No. 90/001,674, Dec. 20, 1988
`
`Reexamination Certificate for:
`Patent No.:
`4,464,223
`Issued:
`Aug. 7, 1984
`Appl. No.:
`538,593
`Filed:
`Oct. 3, 1983
`
`51) Int. Cl....................... H01L 21/312; B44C 1/22;
`CO3C 15/00; C23F 1/02
`52 U.S. C. .................................... 156/643; 156/646;
`156/345; 204/192.32; 204/192.34; 204/298.34
`58) Field of Search ............... 156/345, 643, 646, 653,
`156/656, 657, 659.1, 662, 665; 118/50.1, 728,
`620, 625; 427/38, 39; 204/164, 192.32, 192.35,
`298 TT, 298 E, 298 EP, 298 PP, 298 EM;
`219/121.4, 121.41, 121.43, 121.52, 121.53
`
`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`2,468,174 4/1949 Cotton ................................. 204/312
`3,458,817 7/1969 Cooper et al. ...................... 325/180
`FOREIGN PATENT DOCUMENTS
`0026604 4/1981 European Pat. Off. .
`52-127168. 10/1977 Japan.
`OTHER PUBLICATIONS
`Chapman, "Triode Systems for Plasma Etching', IBM
`Technical Disclosure Bulletin, vol. 21, No. 12, May
`1979, pp. 5006-5007.
`"Triode Plasma Etching' Minkiewicz and Chapman,
`Appl. Phys. Lett. 34(3), Feb. 1979, p. 192.
`Primary Examiner-William A. Powell
`57
`ABSTRACT
`An improved plasma reactor apparatus and method are
`disclosed. Improved uniformity of etching and etch rate
`are achieved in a reactor through the use of electrodes
`powered at high and low frequencies. In one embodi
`ment of the invention the workpiece which is to be
`etched rests on an electrode powered at a low AC fre
`quency of about 100 KHz. A second electrode is pow
`ered at a high AC frequency of about 13.56 MHz. A
`third electrode is maintained at ground potential. High
`and low frequency AC fields acting on a reactant mate
`rial optimize the dissociation of the reactant material
`and the ion energy of the plasma generated reactant
`species.
`
`26
`
`A
`
`COMMON
`GROUND
`
`|| ||
`
`20
`
`10
`
`NYNYNY
`
`MATCHING
`NETWORK
`
`(2)
`
`13.56 MHz
`POWER SUPPLY
`
`12
`1
`
`Z2ZZ 8
`IMO-2 38
`MATCHING
`NEWORK
`
`DC SUPPLY
`
`POWER
`METER
`
`40
`(2)
`POWER
`METER
`
`42
`
`100 KHz
`POWER SUPPLY
`
`35
`
`
`
`TUNED AT
`13.55 MHz
`
`Ex. 1009, Page 7
`
`

`

`U.S. Patent
`
`Apr. 9, 1991
`
`Sheet 1 of 1
`
`B1 4,464,223
`
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`Ex. 1009, Page 8
`
`Ex. 1009, Page 8
`
`
`
`
`

`

`1.
`REEXAMINATION CERTIFICATE
`ISSUED UNDER 35 U.S.C. 307
`
`THE PATENT IS HEREBY AMENDED AS
`INDICATED BELOW.
`
`5
`
`Matter enclosed in heavy brackets I appeared in the
`patent, but has been deleted and is no longer a part of the
`patent; matter printed in italics indicates additions made
`to the patent.
`
`10
`
`AS A RESULT OF REEXAMINATION, IT HAS
`15
`BEEN DETERMINED THAT:
`
`The patentability of claims 8–11 is confirmed.
`Claim 3 is cancelled.
`Claims 1, 2 and 4-7 are determined to be patentable as
`20
`amended.
`New claims 12-15 are added and determined to be pat
`entable.
`
`B1 4,464,223
`2
`5. The reactor of claim 3 1 wherein said third
`electrode is adapted for holding a workpiece and is water
`cooled.
`6. The reactor of claim 1 further comprising A
`reactor apparatus including a reaction volume into which
`reactants are injected and from which reaction products
`are exhausted, and in which said reactants are acted upon
`by electric fields to form a plasma thereof, said apparatus
`comprising
`first, second, and third electrodes,
`said first electrode coupled to electrical ground,
`said second electrode selectively coupled to a high fre
`quency source of AC power, and
`said third electrode selectively coupled to a low frequency
`source of AC power and
`means having a low impedance at the frequency of
`said high frequency source selectively coupled
`between said third electrode and electrical ground.
`7. A plasma reactor apparatus for treating a work
`piece in a glow discharge comprising:
`first, second, and third electrodes separated by insula
`tors for defining a reaction volume in which said work
`piece is located
`a first insulator electrically separating said first and
`second electrodes;
`a second insulator electrically separating said second
`and third electrodes;
`said electrodes and said insulators positioned to
`bound a reaction volume;
`means for admitting reactants to said reaction volume
`and for removing reaction products from said reac
`tion volume;
`a first high frequency AC power supply selec
`tively coupled to between said first electrode
`and said second electrode;
`a second low frequency AC power supply selec
`tively coupled to between said first electrode
`and said third electrode; and
`an electrical ground coupled to said first electrode,
`said first and second power supplies producing different
`frequencies respectively above about 10 Mhz and
`below about 1 Mhz for causing a glow discharge in
`said volume.
`12. The reactor of claim 1 wherein said first electrode is
`adapted for holding a workpiece.
`13. The reactor of claim 1 wherein said second electrode
`is adapted for holding a workpiece.
`14. The reactor of claim 1 wherein said third electrode is
`adapted for holding a workpiece.
`15. The reactor of claim 1 wherein said second electrode
`is cylindrical and one of said first and third electrodes is
`adapted for holding a workpiece.
`
`1. A reactor apparatus including a reaction volume
`25
`into which reactants are injected and from which reac
`tion products are exhausted, and in which said reactants
`are acted upon by electric fields to form a plasma
`thereof, said apparatus comprising:
`first, second, and third electrodes,
`30
`said first electrode coupled to electrical ground,
`said second electrode selectively coupled to a high
`frequency source of AC power, and
`said third electrode selectively coupled to a low fre
`quency source of AC power, and
`35
`wherein one of said electrodes is adapted for holding a
`workpiece.
`2. The reactor of claim 1 wherein said third elec
`trode is further coupled. A reactor apparatus including a
`reaction volume into which reactants are injected and from
`which reaction products are exhausted, and in which said
`reactants are acted upon by electric fields to form a plasma
`thereof, said apparatus comprising
`first, second, and third electrodes,
`45
`said first electrode coupled to electrical ground,
`said second electrode selectively coupled to a high fre
`quency source of AC power, and
`said third electrode selectively coupled to a low frequency
`source of AC power and to a source of DC power.
`4. The reactor of claim 3 1 wherein said third
`electrode is adapted for holding a workpiece and is tem
`perature controlled.
`
`50
`
`55
`
`65
`
`sk
`
`x
`
`k
`
`it
`
`is
`
`Ex. 1009, Page 9
`
`