`US 7,808,184 B2
`(45) Date of Patent:
`*Oct. 5, 2010
`Chistyakov
`
`(10) Patent No.:
`
`US007808184B2
`
`(54)
`
`METHODS AND APPARATUS FOR
`GENERATING STRONGLY-IONIZED
`PLASMAS WITH IONIZATIONAL
`INSTABILITIES
`
`(75)
`
`Inventor: Roman Chistyakov, Andover, MA (US)
`
`(73)
`
`Assignee: Zond, Inc., Mansfield, MA (US)
`
`(*)
`
`Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 882 days.
`
`This patent is subject to a terminal dis-
`claimer.
`
`(21)
`
`Appl. No.: 11/465,574
`
`(22)
`
`Filed:
`
`Aug. 18, 2006
`
`Prior Publication Data
`
`4,458,180 A *
`4,588,490 A
`4,931,169 A
`
`7/1984 Sohval et a1.
`5/ 1986 Cuomo et a1.
`6/1990 Scherer et a1.
`
`.......... 315/lll.81
`
`(Continued)
`FOREIGN PATENT DOCUMENTS
`
`DE
`
`3700633 Cl
`
`5/1998
`
`(Continued)
`OTHER PUBLICATIONS
`
`Kouznetsov, et a1., A Novel Pulsed Magnetron Sputter Technique
`Utilizing Very High Target Power Densities, Surface and Coatings
`Technology, 1999, pp. 290-293, vol. 122, Elsevier.
`
`(Continued)
`
`Primary ExamineriDouglas W Owens
`Assistant ExamineriTung X Le
`(74) Attorney, Agent, or FirmiKurt Rauschenbach;
`Rauschenbach Patent Law Group, LLP
`
`US 2006/0279223 A1
`
`Dec. 14, 2006
`
`(57)
`
`ABSTRACT
`
`Related U.S. Application Data
`
`Continuation of application No. 10/708,281, filed on
`Feb. 22, 2004, now Pat. No. 7,095,179.
`
`Int. Cl.
`
`(2006.01)
`H05B 31/26
`U.S. Cl.
`............................ 315/111.21; 315/111.41;
`315/1 1 1.71
`Field of Classification Search ........................ 315/
`11121711191; 216/67,71; 118/723VE,
`118/723 R; 156/345.33; 204/192.12, 192.1,
`204/298.08
`
`See application file for complete search history.
`References Cited
`
`U.S. PATENT DOCUMENTS
`9/1963 Wilcox et a1.
`
`3,104,345 A
`
`Methods and apparatus for generating strongly-ionized plas-
`mas are disclosed. A strongly-ionized plasma generator
`according to one embodiment includes a chamber for confin-
`ing a feed gas. An anode and a cathode assembly are posi-
`tioned inside the chamber. A pulsed power supply is electri-
`cally connected between the anode and the cathode assembly.
`The pulsed power supply generates a multi-stage voltage
`pulse that includes a low-power stage with a first peak voltage
`having a magnitude and a rise time that is sufficient to gen-
`erate a weakly-ionized plasma from the feed gas. The multi-
`stage voltage pulse also includes a transient stage with a
`second peak voltage having a magnitude and a rise time that
`is sufficient to shift an electron energy distribution in the
`weakly-ionized plasma to higher energies that increase an
`ionization rate which results in a rapid increase in electron
`density and a formation of a strongly-ionized plasma.
`
`20 Claims, 16 Drawing Sheets
`
`l-V(vo|ts)|, l(amps), P(kW)
`A
`
`(65)
`
`(63)
`
`(51)
`
`(52)
`
`(58)
`
`(56)
`
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`650’
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`450’
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`350'—
`CURRENT
`300*
`(I)
`287
`288 a
`
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`
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`
`20077
`150—
`100—
`’
`POWER (P)
`
`>
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`
`|
`l
`TIME
`l
`l
`|
`1
`|
` 600.0psec700.0usec
`1.4msec
`
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`0.01Lsec
`400.0psec
`8001111560
`1.0msec
`1.2msec
`1.3msec
`300.0usec
`900.011.5120
`1.1msec
`1011011531:
`500014560
`
`
`
`290
`
`A
`
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`
`m
`252 j
`‘
`
`
`
`¥6%LTAGE (V)
`
`______
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`
`50—-
`
`INTEL 1001
`
`INTEL 1001
`
`
`
`US 7,808,184 B2
`Page 2
`
`U.S. PATENT DOCUMENTS
`
`3/1991 Giapis etal.
`5,002,631 A
`5/1991 Gruen
`5,015,493 A
`4/1994 Mark
`5,303,139 A
`.................... 427/577
`12/1995 Lee et a1.
`5,476,693 A
`7/1996 Goebeletal.
`.......... 315/111.81
`5,537,005 A
`10/1996 Suzuki etal.
`5,565,247 A
`4/1997 Boiling
`5,616,224 A
`2/1998 Drummond et al.
`5,718,813 A
`3/1998 Okamura et a1.
`5,728,278 A
`5,828,176 A * 10/1998 Goebel
`.................. 315/111.41
`5,844,195 A
`12/1998 Fairbairn et al.
`6,124,675 A
`9/2000 Bertrandet al.
`6,197,165 B1
`3/2001 Dreweryet al.
`6,222,321 B1
`4/2001 Schollet al.
`6,254,745 B1
`7/2001 Vukovic
`6,296,742 B1
`10/2001 Kouznetsov
`6,327,163 B1
`12/2001 Petr
`6,342,132 B1
`1/2002 Rossnagel
`6,355,992 B1
`3/2002 Via
`6,359,424 B2
`3/2002 Iida et al.
`6,413,382 B1
`7/2002 Wang et a1.
`6,416,634 B1
`7/2002 Mostovoy et al.
`6,521,099 B1
`2/2003 Drummond et al.
`6,621,674 B1
`9/2003 Zahringer et al.
`6,633,017 B1
`10/2003 Drummond et al.
`6,735,099 B2
`5/2004 Mark
`6,805,779 B2
`10/2004 Chistyakov
`6,806,651 B1
`10/2004 Chistyakov
`6,806,652 B1
`10/2004 Chistyakov
`6,808,607 B2
`10/2004 Christie
`6,853,142 B2
`2/2005 Chistyakov
`6,896,773 B2
`5/2005 Chistyakov
`6,896,775 B2
`5/2005 Chistyakov
`6,903,511 B2
`6/2005 Chistyakov
`2002/0008480 A1*
`1/2002 Yamazaki et a1.
`2004/0020760 A1
`2/2004 Kouznetsov
`2004/0060813 A1
`4/2004 Chistyakov
`2004/0086434 A1
`5/2004 Gadgil et a1.
`2004/0094411 A1
`5/2004 Chistyakov
`2004/0112735 A1
`6/2004 Saigaletal.
`2004/0124077 A1
`7/2004 Christie
`2005/0092596 A1
`5/2005 Kouznetsov
`2005/0103620 A1
`5/2005 Chistyakov
`2005/0109607 A1
`5/2005 Ehiasarian et a1.
`2005/0173239 A1
`8/2005 Somekh et a1.
`2005/0184669 A1
`8/2005 Chistyakov
`2005/0247554 A1
`11/2005 Saigaletal.
`2009/0263966 A1
`10/2009 Weichart et a1.
`
`...... 315/111.21
`
`FOREIGN PATENT DOCUMENTS
`
`EP
`EP
`EP
`JP
`RU
`RU
`WO
`WO
`
`1046726 A2
`1 260 603 A1
`1046726 B1
`2004 010979 A
`2029411 C1
`2 058 429 C1
`98/40532
`02/103078 A1
`
`10/2000
`11/2002
`7/2009
`1/2001
`2/1995
`4/1996
`9/1998
`12/2002
`
`OTHER PUBLICATIONS
`
`Steinbruchel, A Simple Formula for Low-Energy Sputtering Yields,
`Applied Physics A., 1985, pp. 37-42, vol. 36, Springer, Verlag.
`Daugherty, et al., Attachment-Dominated Electron-Beam-Ionized
`Discharges, Applied Physics Letters, May 15, 1976, pp. 581-583, vol.
`28, No. 10, American Institute of Physics.
`Fajans, et al., Bifurcations in Elliptical, Asymmetric Non-Neutral
`Plasmas, Physics of Plasmas, Oct. 2000, pp. 3929-3933, vol. 7, No.
`10, American Institute of Physics.
`
`Dekoven, et al., Carbon Thin Film Deposition Using High Power
`Pulsed Magnetron Sputtering, 46th Annual Technical Conference
`Proceedings, 2003, pp. 158-165, Society ofVacuum Coaters.
`Stark, et al., Electron Heating in Atmospheric Pressure Glow Dis-
`charges, Journal oprplied Physics, Apr. 2001, p. 3568, vol. 89, No.
`7, American Institute of Physics.
`Gudmundsson, et al., Evolution of the Electron Energy Distribution
`and Plasma Parameters in a Pulsed Magnetron Discharge, Applied
`Physics Letters, May 28, 2001, pp. 3427-3429, American Institute of
`Physics.
`Mozgrin, et al., High-Current Low-Pressure Quasi-Stationary Dis-
`charge in a Magnetic Field: Experimental Research, Plasma Physics
`Reports, 1995, vol. 21, No. 5, pp. 400-409, Interperiodica Publishing.
`Garrigues, et al., Hybrid and Particle-In-Cell Models of a Stationary
`Plasma Thruster, Plasma Sources Sci. Technol., 2000, pp. 219-226,
`vol. 9, IOP Publishing Ltd., UK.
`Kudiyavtsev, et al., Ionization Relaxation in a Plasma Produced by a
`Pulsed Inert-Gas Discharge, Sov. Phys. Tech. Phys., Jan. 1983, pp.
`30-35, vol. 28, No. 1, American Institute of Physcis.
`Biberman, et al., Low-Temperature Plasmas with Nonequilibrium
`Ionization, Sov. Phys. Usp.. Jun. 1979, pp. 411-432, vol. 22, No. 6.
`Thornton, Magnetron Sputtering: Basic Physics and Application to
`Cylindrical Magnetrons, J. Vac. Sci. Technol. Mar/Apr. 1978, pp.
`171-177, vol. 15, No. 2.
`Helmersson, Metallization by Pulsed High-Power Sputtering,
`[online]. [retrieved on Nov. 21, 2003]. Retrieved from WWW.inf.liu.
`se/thinprogram/projects/p2.html.
`Pisarev, Modification of the Surface of Perforated Polymer MF-4SK
`in Low-Pressure, High Current Quasi-Stable Discharge Plasma in
`Magnetic Field, [online]. [retrieved on Dec. 30, 2003]. Retrieved
`from WWW.tech-db.ru/lstc/db/pra.nsf/we/0624.
`Gudmundsson, et al., Observation of Ion-Acoustic Solitons in a
`Pulsed Magnetron Sputtering Discharge, 56th-Gaseous Electronics
`Conference-2003, Oct. 24, 2003, pp. 1-14.
`Matossian, et al., Operating Characteristics of a 100kV, 100kW
`Plasma Ion Implantation Facility, Surface Coatings & Technology,
`1996, pp. 92-97, vol. 85.
`Fajans, et al., Second Harmonic Autoresonant Control of the 1:1
`Diocotron Mode in Pure-Electron Plasmas, Physical Review E, Sep.
`2000, pp. 4131-4136, vol. 62, No. 3.
`J.T. Gudmundsson, et al., Spatial and Temporal Behavior of the
`Plasma Parameters in a Pulsed Magnetron Discharge, Surface &
`Coatings Technology, 2002. pp. 249-256, vol. 161, Elsevier Science.
`Biberman, et al., Chapter Eight: Transient Nonequilibrium Plasmas,
`Kinetics of Nonequilibrium Low Temperature Plasmas, 1987, pp.
`321, 360-372, Plenum Publishing Corporation, New York, USA.
`Gudmundsson, et al., Observation of Solitons in a Pulsed Magnetron
`Sputtering Discharge [online]. [retrieved on Dec. 8, 2003]. Retrieved
`from WWW.eps.org/aps/meet/GECO3/baps/abs/s300.html.
`The State of the Art in Pulsed High Power [online]. [retrieved on Jul.
`15,
`2002].
`Retrieved
`from WWthysiqueindustrie.
`com/,pulseipowerhtml.
`Encyclopedia of Low Temperature Plasma, Editor V.E. Fortov, 2000,
`vol. 3, p. 123.
`Encyclopedia of Low Temperature Plasma, Editor V.E. Fortov, 2000,
`vol. 3, p. 119.
`Hart, et al., Growth of Soliton-like Structures From Normal Modes
`and Particle Loss From a Nonneutral Plasma, [online]. Non-Neutral
`Plasmas, Archibald/Cochran, 3rd Floor, Tower, Nov. 7, 1995.
`Vladimirov, V., Voltage-Current Characteristics of a Gas Magnetron
`in the Case of Intense Cathode Sputtering, Sov. J. Plasma Phys.,
`Jan-Feb. 1981, pp. 114-118, vol. 7, No. 1.
`Lutsenko, E.I., Instability Mechanisms in a High-Current Straight
`Discharge at a Low Gas Pressure, Sov. J. Plasma Phys., Jan-Feb.
`1984, pp. 87-95, vol. 10, No. 1.
`“Notification of Transmittal of the International Search Report and
`the Written Opinion of the International Searching Authority, or the
`Declaration” for PCT/US08/004644, Aug. 21, 2008, 14 pages, the
`International Searching Authority/EPO, Rij swijk, The Netherlands.
`“Notification of Transmittal of the International Search Report and
`the Written Opinion of the International Searching Authority, or the
`Declaration” for PCT/USO 5/005022, Jul. 8, 2005, 14 pages, the Inter-
`national Searching Authority/EPO, Rij swijk, The Netherlands.
`
`
`
`US 7,808,184 B2
`Page 3
`
`
`
`
`
`
`
`“Office Action” for L
`.S.App1. No. 10/065,277, Jan. 15, 2004, 12
`pages, The LSPTO, LS.
`“Office Action” for L
`.s. Appl. No. 10/065,277, Aug. 30, 2004, 14
`pages, The LSPTO, LS.
`“Office Action” for L
`.S.App1. No. 10/065,277, May 27, 2005, 13
`pages, The LSPTO, LS.
`“Office Action” for L.
`S. Appl. No. 10/065,277, Jan. 11, 2006, 15
`pages, The L SPTO, L S.
`“Office Action” for US. Appl. No. 10/065,277, Jul. 18,2006, 6
`pages, The L SPTO, L S.
`“Office Action” for US Appl. No. 10/065, 629, Oct. 7, 2003,11
`pages, TheLSPTO, LS.
`“Office Action” for L
`.S. Appl. No. 10/065,739, Feb. 18, 2004, 14
`pages, The L SPTO, L S.
`“Office Action” for L
`.S.App1. No. 10/065,739, May 20, 2004, 14
`pages, The L SPTO, L S.
`“Office Action” for L
`.s. Appl. No. 10/249,202, Feb. 11, 2004, 6
`pages, The L SPTO, L S.
`“Office Action” for L
`.s. Appl. No. 10/249,595, Apr. 22, 2004, 5
`pages, The L SPTO, L S.
`“Office Action” for L
`.s. Appl. No. 10/249,774, Aug. 27, 2004, 6
`pages, The L SPTO, L S.
`“Office Action” for L
`.S. Appl. No. 10/249,844, Apr. 23, 2004, 5
`pages, The L SPTO, L S.
`“OfficeAction” for US. Appl. No. 10/553,893, Mar. 7, 2008, 6 pages,
`The USPTO, US.
`“Office Action” for L
`.S.App1. No. 10/708,281, May 18, 2005, 15
`pages, The L SPTO, L S.
`“Office Action” for L
`.S.App1.No. 10/708,281, Dec. 20, 2005, 14
`pages, The L SPTO, L S.
`“Office Action” for L
`.8. Appl. No. 10/710,946, Nov. 16, 2007, 7
`pages, The L SPTO, L S.
`“Office Action” for L
`.S. Appl. No. 10/710,946, Feb. 21, 2008, 18
`pages, The L SPTO, L S.
`“Office Action” for L
`.S. Appl. No. 10/710,946, Apr. 10, 2009, 18
`pages, The L SPTO, L S.
`“Office Action” for L
`.s. Appl. No. 10/897,257, Mar. 27, 2008, 13
`pages, The L SPTO, L S.
`“Office Action” for L
`.S. Appl. No. 10/897,257, Jan. 14, 2009, 7
`pages, The L SPTO, L S.
`“Office Action” for L
`.S. Appl. No. 10/949,427, Apr. 21, 2006, 6
`pages, The L SPTO, L S.
`“Office Action” for L
`.8. Appl. No. 11/091,814, Jul. 14, 2008, 19
`pages, The LSPTO, LS.
`“Office Action” for L
`.S. Appl. No. 11/130,315, Jul. 3, 2008, 10
`pages, The L SPTO, L S.
`“Office Action” for L
`.S. Appl. No. 11/162,824, Apr. 28, 2008, 8
`pages, The LSPTO, LS.
`“Office Action” for L
`.S.App1. No. 11/162,824, Jan. 23, 2009, 10
`pages, The LSPTO, LS.
`“Office Action” for L
`.S. Appl. No. 11/162,824, May 18, 2009, 9
`pages, The L SPTO, L S.
`“Office Action” for L
`.S. Appl. No. 11/183,463, Oct. 24, 2008, 7
`
`pages, The L SPTO, L S.
`
`“Office Action” for L
`S. Appl. No. 11/376,036, Jul. 25, 2007, 7
`pages, The L SPTO, L S.
`“Office Action” for L.
`S. Appl. No. 11/608, 833, Mar. 11, 2009, 8
`pages, The L SPTO, L S.
`“OfficeAction”forU. S. Appl. No. 12/245, 193, Apr. 2, 2009, 4pages,
`The USPTO, US.
`“Notification Concerning Transmittal of International Preliminary
`Report on Patentability (Chapter I ofthe Patent Cooperation Treaty)”
`for PCT/US2008/004644, Nov. 5, 2009, 10 pgs., The International
`Bureau of WIPO, Geneva, Switzerland.
`“Notification Concerning Transmittal of International Preliminary
`Report on Patentability (Chapter I ofthe Patent Cooperation Treaty)”
`for PCT/US2008/004605, Oct. 29, 2009, 9 pgs., The International
`Bureau of WIPO, Geneva, Switzerland.
`Bugaev, S. P., et al.,
`Investigation of a High-Current Pulsed
`Magnetron Discharge Initiated in the Low-Pressure Diffuse Arc
`Plasma, XVIIth International Symposium on Discharges and Elec-
`trical Insulation in Vacuum, 1996, pp. 1074-1076.
`
`Bugaev, S. P., et al., Ion-Assisted Pulsed Magnetron Sputtering
`Deposition of Ta-C Films, Thin Solid Films, 2001, pp. 16-26, vol.
`389, Elsevier Science B.V.
`D’Couto, G. C., et al., In Situ Physical Vapor Deposition ofIonized Ti
`and TiN Thin Films Using Hollow Cathode Magnetron Plasma
`Source, J.Vac. Sci. Technol. B, Jan/Feb. 2001,pp. 244-249, vol. 19.
`No. 1, American Vacuum Society.
`Ehiasarian, A. P, et al., High Power Pulsed Magnetron Sputtered
`CrNX Films, Dunnschicht-/Plasmatechnik, 2003, pp. 1480-1487.
`Ehiasarian, A. P, et al., Influence of High Power Densities on the
`Composition of Pulsed Magnetron Plasmas, Vacuum, 2002, pp. 147-
`154, vol. 65, Elsevier Science Ltd.
`Gudmundsson, J. T. et al., Spatial and Temporal Behavior of the
`Plasma Parameters in a Pulsed Magnetron Discharge, Surface and
`Coatings Technology, 2002, pp. 249-256, vol. 161, Elsevier Science
`B.V.
`Gudmundsson, J. T. et al., Evolution of the Electron Energy Distri-
`bution and Plasma Parameters in a Pulsed Magnetron Discharge,
`Applied Physics Letters, May 28, 2001, pp. 3427-3429, vol. 78, No.
`22, American Institute of Physics.
`Hopwood, J., Ionized Physical Vapor Deposition of Integrated Cir-
`cuit Interconnects, Physics of Plasmas, May 1998, pp. 1624-1631,
`vol. 5, No. 5, American Institute of Physics.
`Kervalishvii, N. A., eta1., Low-Pressure Discharge in Crossed Fields
`(E.H) in a Magnetron and Penning Cell, Sov. Phys. Tech. Phys., 1976,
`pp. 1591-1596, vol. 20, No. 12, American Institute of Physics.
`Korneev, V.V., Electric Fields in a Nonequilibrium Inhomogeneous
`Weakly Ionized Plasma, Sov. J. Plasma Phys., Nov-Dec. 1978, pp.
`784-785, vol. 4, No. 6, American Institute of Physics.
`Lebedev, S. Ya., et al., Cathode Sputtering Under the Action of
`Cesium Ions, Soviet PhysicsiTechnical Physics, Dec. 1964, pp.
`854-856, vol. 9, No. 6.
`Oks, E. M., et al., Plasma Emission Properties of a Superdense Glow
`Discharge Excited in Crossed Electric and Magnetic Fields, Sov.
`Phys. Tech. Phys., Jun. 1991, pp. 712-714, vol. 36, No. 6, American
`Institute of Physics.
`Rasmussen, C. E., et al., Ionization and Current Growth in an E X B
`Discharge, Plasma Physics, 1969, pp. 183-195, vol. 11, Pergamon
`Press, Northern Ireland.
`Redhead, P. A., Instabilities in Crossed-Field Discharges At Low
`Pressures, Vacuum, 1988, pp. 901-906, vol. 38, No. 8-10, Pergamon
`Press, Great Britain.
`Steinbruchel, Ch., A Simple Formula for Low-Energy Sputtering
`Yields, Appl. Phys. A., 1985, pp. 37-42, vol. 36, Springer-Verlag.
`Westwood, W. D., The Current-Voltage Characteristic of Magnetron
`Sputtering Systems, J. Appl. Phys., Dec. 1983, pp. 6841-6846, vol.
`54, No. 12, American Institute of Physics.
`“Office Action” for European Patent Application No. 03 -781-508.1-
`1226, Apr. 1, 2008, 5 pages, the European Patent Office.
`“Response to Office Action” for European Patent Application No.
`03-781-508.1-1226, Oct. 13,2008, 13 pages.
`“Supplement to Response to Office Action” for European Patent
`Application No. 03-781-508.1-1226, Oct. 23, 2008, 4 pages.
`“Office Action” for European Patent Application No. 03 -781-508.1-
`1226, Apr. 7, 2010, 3 pages, the European Patent Office.
`“Office Action” for European Patent Application No. 03 -779-3 87 .4-
`1215, Oct. 10, 2007, 4 pages, the European Patent Office.
`“Response to Office Action” for European Patent Application No.
`03-779-387.4-1215, Apr. 21, 2008, 15 pages.
`“Summons to Oral Proceedings” for European Patent Application
`No. 03 -779-3 87 .4-1215, Dec. 15, 2009, 6 pages, the European Patent
`Office.
`“Office Action” for European Patent Application No. 03 -776-584.9-
`1226, Sep. 18, 2008, 6 pages, the European Patent Office.
`“Response to Office Action” for European Patent Application No.
`03-776-584.9-1226, Jul. 23, 2009, 12 pages.
`“Office Action” for European Patent Application No. 04-749-844.9-
`2208, Jan. 28, 2009, 2 pages, the European Patent Office.
`“Office Action” for European Patent Application No. 04-750-797.5-
`2208, Oct. 16, 2008, 5 pages, the European Patent Office.
`“Office Action” for European Patent Application No. 04-716-928.9-
`2208, Dec. 15, 2006, 5 pages, the European Patent Office.
`
`
`
`US 7,808,184 B2
`
`Page 4
`
`“Response to Office Action” for European Patent Application No.
`04-716-928.9-2208, Jul. 24, 2007, 20 pages.
`“Office Action” for European Patent Application No. 04-810-268.5.
`2208, Apr. 23, 2009, 3 pages, the European Patent Office.
`“Response to Office Action” for European Patent Application No.
`04-810-268.5.2208, May 29, 2009, 2 pages.
`“Office Action” for European Patent Application No. 05-723-194.6-
`1226, Nov. 5, 2009, 6 pages, the European Patent Office.
`
`“Office Action” for European Patent Application No. 05-800-880.6-
`1226, Jan. 25, 2010, 3 pages, the European Patent Office.
`“Office Action” for Japanese Patent Application No. 2004-551595,
`Aug. 24, 2009, 2 pages, the Japanese Patent Office.
`“Response to Office Action” for Japanese Patent Application No.
`2004-551595, Feb. 18, 2010, 3 pages.
`
`* cited by examiner
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`US 7,808,184 B2
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`Sheet 10 of 16
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`US 7,808,184 B2
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`Oct. 5, 2010
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`Sheet 11 0f 16
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`US 7,808,184 B2
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`Sheet 12 0f 16
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`US 7,808,184 132
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`US 7,808,184 B2
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`Oct. 5, 2010
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`Sheet 14 of 16
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`US 7,808,184 B2
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`PRIMARY SECONDARY
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`PRIOR ART
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`Sheet 16 of 16
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`US 7,808,184 B2
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`US 7,808,184 B2
`
`1
`METHODS AND APPARATUS FOR
`GENERATING STRONGLY-IONIZED
`PLASMAS WITH IONIZATIONAL
`INSTABILITIES
`
`RELATED APPLICATION SECTION
`
`This application is a continuation application of US.
`patent application Ser. No. 10/708,281 , filed on Feb. 22, 2004,
`entitled “Methods and Apparatus for Generating Strongly
`lonized Plasmas with Ionizational Instabilities,” the entire
`application of which is Incorporated herein by reference.
`
`BACKGROUND OF INVENTION
`
`A plasma can be created in a chamber by igniting a direct
`current (DC) electrical discharge between two electrodes in
`the presence of a feed gas. The electrical discharge generates
`electrons in the feed gas that ionize atoms thereby creating the
`plasma. The electrons in the plasma provide a path for an
`electric current to pass through the plasma. The energy sup-
`plied to the plasma must be relatively high for applications,
`such as magnetron plasma sputtering. Applying high electri-
`cal currents through a plasma can result in overheating the
`electrodes as well as overheating the work piece in the cham-
`ber. Complex cooling mechanisms can be used to cool the
`electrodes and the work piece. However, the cooling can
`cause temperature gradients in the chamber. These tempera-
`ture gradients can cause non-uniformities in the plasma den-
`sity which can cause non-uniform plasma process.
`Temperature gradients can be reduced by pulsing DC
`power to the electrodes. Pulsing the DC power can allow the
`use of lower average power. This results in a lower tempera-
`ture plasma process. However, pulsed DC power systems are
`prone to arcing at plasma ignition and plasma termination,
`especially when working with high-power pulses. Arcing can
`result in the release of undesirable particles in the chamber
`that can contaminate the work piece.
`Plasma density in known plasma systems is typically
`increased by increasing the electrode voltage. The increased
`electrode voltage increases the discharge current and thus the
`plasma density. However, the electrode voltage is limited in
`many applications because high electrode voltages can effect
`the properties of films being deposited or etched. In addition,
`high electrode voltages can also cause arcing which can dam-
`age the electrode and contaminate the work piece.
`
`BRIEF DESCRIPTION OF DRAWINGS
`
`This invention is described with particularity in the
`detailed description and claims. The above and further advan-
`tages of this invention may be better understood by referring
`to the following description in conjunction with the accom-
`panying drawings, in which like numerals indicate like struc-
`tural elements and features in various figures. The drawings
`are not necessarily to scale, emphasis instead being placed
`upon illustrating the principles of the invention.
`FIG. 1 illustrates a cross-sectional view of a plasma sput-
`tering apparatus having a pulsed direct current (DC) power
`supply according to one embodiment of the invention.
`FIG. 2 is measured data of discharge voltage as a function
`of discharge current for a prior art low-current plasma and a
`high-current plasma according to the present invention.
`FIG. 3 is measured data of a particular voltage pulse gen-
`erated by the pulsed power supply of FIG. 1 operating in a
`low-power voltage mode.
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`2
`
`FIG. 4 is measured data of a multi-stage voltage pulse that
`is generated by the pulsed power supply of FIG. 1 that creates
`a strongly-ionized plasma according to the present invention.
`FIG. SA-FIG. 5C are measured data of other illustrative
`
`multi-stage voltage pulses generated by the pulsed power
`supply of FIG. 1.
`FIG. 6A and FIG. 6B are measured data of multi-stage
`voltage pulses generated by the pulsed power supply of FIG.
`1 that illustrate the effect of pulse duration in the transient
`stage of the pulse on the plasma discharge current.
`FIG. 7A and FIG. 7B are measured data of multi-stage
`voltage pulses generated by the pulsed power supply of FIG.
`1 that show the effect of the pulsed power supply operating
`mode on the plasma discharge current.
`FIG. 8 is measured data for an exemplary single-stage
`voltage pulse generated by the pulsed power supply of FIG. 1
`that produces a high-density plasma according to the inven-
`tion that is useful for high-deposition rate sputtering.
`FIG. 9 illustrates a cross-sectional view of a plasma sput-
`tering apparatus having a pulsed direct current (DC) power
`supply according to another embodiment of the invention.
`FIG. 10 illustrates a schematic diagram of a pulsed power
`supply that can generate multi-step voltage pulses according
`to the present invention.
`FIG. 11 illustrates a schematic diagram of a pulsed power
`supply having a magnetic compression network for supplying
`high-power pulses.
`FIG. 12 illustrates a schematic diagram of a pulsed power
`supply having a Blumlein generator for supplying high-
`power pulses.
`FIG. 13 illustrates a schematic diagram of a pulsed power
`supply having a pulse cascade generator for supplying high-
`power pulses.
`
`DETAILED DESCRIPTION
`
`FIG. 1 illustrates a cross-sectional view of a plasma sput-
`tering apparatus 100 having a pulsed direct current (DC)
`power supply 102 according to one embodiment ofthe inven-
`tion. The plasma sputtering apparatus 100 includes a vacuum
`chamber 104 for containing a plasma. The vacuum chamber
`104 can be coupled to ground 105. The vacuum chamber 104
`is positioned in fluid communication with a vacuum pump
`106 that is used to evacuate the vacuum chamber 104 to high
`vacuum. The pressure inside the vacuum chamber 104 is
`generally less than 10'1 Torr for most plasma operating con-
`ditions. A process or feed gas 108 is introduced into the
`vacuum chamber 104 through a gas inlet 112 from a feed gas
`source 110, such as an argon gas source. The flow of the feed
`gas is controlled by a valve 114. In some embodiments, the
`gas source is an excited atom or metastable atom source.
`The plasma sputtering apparatus 100 also includes a cath-
`ode assembly 116. The cathode assembly 116 shown in FIG.
`1 is formed in the shape of a circular disk, but can be formed
`in other shapes. In some embodiments, the cathode assembly
`116 includes a target 118 for sputtering. The cathode assem-
`bly 116 is electrically connected to a first terminal 120 of the
`pulsed power supply 102 with an electrical transmission line
`122.
`
`A ring-shaped anode 124 is positioned in the vacuum
`chamber 104 proximate to the cathode assembly 116. The
`anode 124 is electrically connected to ground 105. A second
`terminal 125 of the pulsed power supply 102 is also electri-
`cally connected to ground 105. In other embodiments, the
`anode 124 is electrically connected to the second terminal
`125 of the pulsed power supply 102 which is not at ground
`potential.
`
`
`
`US 7,808,184 B2
`
`3
`A housing 126 surrounds the cathode assembly 116. The
`anode 124 can be integrated with or electrically connected to
`the housing 126. The outer edge 127 of the cathode assembly
`116 is electrically isolated from the housing 126 with insula-
`tors 128. The gap 129 between the outer edge 127 of the
`cathode assembly 116 and the housing 126 can be an air gap
`or can include a dielectric material.
`
`I11 some embodiments, the plasma sputtering apparatus
`100 includes a magnet assembly 130 that generates a mag-
`netic field 132 proximate to the target 118. The magnetic field
`132 is less parallel to the surface ofthe cathode assembly 116
`at the poles of the magnets in the magnet assembly 130 and
`more parallel to the surface ofthe cathode assembly 116 in the
`region 134 between the poles of the magnets in the magnetic
`assembly 130. The magnetic field 132 is shaped to trap and
`concentrate secondary electrons emitted from the target 118
`that are proximate to the target surface 133. The magnet
`assembly can consist of rotating magnets.
`The magnetic field 132 increases the density of electrons
`and therefore, increases the plasma density in the region 134
`that is proximate to the target surface 133. The magnetic field
`132 can also induce an electron Hall current 135 that is
`
`formed by the crossed electric and magnetic fields. The
`strength of the electron Hall current 135 depends, at least in
`part, on the density of the plasma and the strength of the
`crossed electric and magnetic fields.
`The plasma sputtering apparatus 100 also includes a sub-
`strate support 136 that holds a substrate 138 or other work
`piece for plasma processing. In some embodiments, the sub-
`strate support 136 is biased with a RF field. In these embodi-
`ments, the substrate support 136 is electrically connected to
`an output 140 of a RF power supply 142 with an electrical
`transmission line 144. A matching network (not shown) may
`be used to coupled the RF power supply 142 to the substrate
`support 136. In some embodiments, a temperature controller
`148 is thermally coupled to the substrate support 136. The
`temperature controller 148 regulates the temperature of the
`substrate 138.
`
`I11 some embodiments, the plasma sputtering apparatus
`100 includes an energy storage device 147 that provides a
`source of energy that can be controllably released into the
`plasma. The energy storage device 147 is electrically coupled
`to the cathode assembly 116. In one embodiment, the energy
`storage device 147 includes a capacitor bank.
`In operation, the vacuum pump 106 evacuates the chamber
`104 to the desired operating pressure. The feed gas source 110
`injects feed gas 108 into the chamber 104 through the gas inlet
`112. The pulsed power supply 102 applies voltage pulses to
`the cathode assembly 116 that cause an electric field 149 to
`deve