IPR2014-00807
`U.S. Patent No. 7,604,716
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`UNITED STATES PATENT AND TRADEMARK OFFICE
`__________________
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`__________________
`
`TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY, LTD.,
`TSMC NORTH AMERICA CORPORATION,
`FUJITSU SEMICONDUCTOR LIMITED,
`FUJITSU SEMICONDUCTOR AMERICA, INC.,
`ADVANCED MICRO DEVICES, INC., RENESAS ELECTRONICS
`CORPORATION, RENESAS ELECTRONICS AMERICA, INC.,
`GLOBAL FOUNDRIES U.S., INC., GLOBALFOUNDRIES DRESDEN
`MODULE ONE LLC & CO. KG, GLOBALFOUNDRIES DRESDEN MODULE
`TWO LLC & CO. KG, TOSHIBA AMERICA ELECTRONIC COMPONENTS,
`INC., TOSHIBA AMERICA INC., TOSHIBA AMERICA INFORMATION
`SYSTEMS, INC., TOSHIBA CORPORATION, and
`THE GILLETTE COMPANY
`
`Petitioners
`
`v.
`
`ZOND, LLC
`Patent Owner
`__________________
`
`Case IPR2014-008071
`Patent 7,604,716 B2
`__________________
`
`PATENT OWNER’S RESPONSE
`35 USC § 316 AND 37 CFR § 42.120
`
`
`
`1 Cases IPR 2014-00846, IPR 2014-0974, and IPR 2014-01065 have been joined
`with the instant proceeding.
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`i
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`IPR2014-00807
`U.S. Patent No. 7,604,716
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`TABLE OF CONTENTS
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`I. INTRODUCTION ................................................................................................ 1
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`II. TECHNOLOGY BACKGROUND .................................................................... 6
`
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`A. Plasma Fundamentals. .................................................................................... 6
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`
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`B. Plasma Ignition ............................................................................................... 8
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`C. High-Density Plasmas ..................................................................................... 9
`
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`III. THE ‘716 PATENT ......................................................................................... 10
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`IV. ARGUMENT. ................................................................................................. 14
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`A. Wang. ............................................................................................................ 16
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`B. Kudryavtsev. ................................................................................................. 21
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`C. Wang and Kudryavtsev Do Not Suggest Generating a Strongly-Ionized
`Plasma Without Developing an Electrical Breakdown Condition as Required by
`the Challenged Claims of the ’716 Patent. .......................................................... 26
`
`D. It Would Not Have Been Obvious To Combine the Teachings of Wang and
`Kudryavtsev To Achieve the Invention Claimed in the ’716 Patent. .................. 31
`
`E. The Combination of Wang and Kudryavtsev Does Not Suggest The
`Invention Recited in Independent Claim 26. ....................................................... 34
`
`F. The Combination of Wang and Kudryavtsev Does Not Suggest That Either of
`“a rise time and magnitude of the electrical pulse” is “selected to increase an
`density of the weakly-ionized plasma,” as Recited in Dependent Claim 16. ...... 38
`
`G. The Combination of Wang and Kudryavtsev Does Not Suggest That
`Either of “a rise time and magnitude of the electrical pulse” is “selected to
`excite atoms in the weakly-ionized plasma to generate secondary electrons
`that increase an ionization rate of the weakly-ionized plasma,” as Recited in
`Dependent Claim 17 or “increase an ionization rate of the excited atoms in
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`IPR2014-00807
`U.S. Patent No. 7,604,716
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`the weakly-ionized plasma,” as Required by Dependent Claim 30. ................... 39
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`H. The Combination of Wang and Kudryavtsev Does Not Suggest a Cathode
`that is Positioned Adjacent to the Anode “form[ing] a gap there between,” as
`Recited in Claim 28. ............................................................................................ 41
`
`I. The Combination of Wang and Kudryavtsev Does Not Suggest “a dimension
`of the gap between the anode and the cathode is chosen to increase an ionization
`rate of the excited atoms in the weakly-ionized plasma,” as Required by
`Dependent Claim 29. ........................................................................................... 42
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`V. CONCLUSION ................................................................................................. 44
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`IPR2014-00807
`U.S. Patent No. 7,604,716
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`TABLE OF AUTHORITIES
`
`
`
`
`
`
`CASES
`Alza Corp. v. Mylan Labs., Inc.,
`464 F.3d 1286 (Fed. Cir. 2006) ........................................................................... 16
`
`
`Cross Med. Prods., Inc. v. Medtronic Sofamor Danek, Inc.,
`424 F.3d 1293 (Fed. Cir. 2005) ........................................................................... 16
`
`
`Heart Failure Technologies, LLC v. Cardiokinetix, Inc.,
`IPR2013-00183 (P.T.A.B. July 31, 2013) ........................................................... 15
`
`
`KSR Int’l Co. v. Teleflex Inc.,
`550 U.S. 398 (2007) ............................................................................................ 15
`
`
`Mintz v. Dietz & Watson, Inc.,
`679 F.3d 1372 (Fed. Cir. 2012) ........................................................................... 15
`
`
`Proctor & Gamble Co. v. Teva Pharm. USA, Inc.,
`566 F.3d 989 (Fed. Cir. 2009) ....................................................................... 14, 15
`
`
`
`STATUTES
`35 U.S.C. § 316 (e) ........................................................................................... 39, 40
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`IPR2014-00807
`U.S. Patent No. 7,604,716
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`EXHIBIT LIST
`
`Exhibit
`No.
`Ex. 2001 Affidavit of Etai Lahav in Support of Patent Owner’s Motion for Pro
`Hac Vice Admission
`
`Description
`
`Ex. 2002 Affidavit of Maria Granovsky in Support of Patent Owner’s Motion
`for Pro Hac Vice Admission
`
`Ex. 2003 Affidavit of Tigran Vardanian in Support of Patent Owner’s Motion
`for Pro Hac Vice Admission
`
`Ex. 2004 Declaration of Larry D. Hartsough, Ph.D.
`
`Ex. 2005 Transcript of Deposition of Dr. Uwe Kortshagen, IPR2014-00807,
`-00808, -01099 & -01100, Dec. 22, 2014.
`
`Ex. 2006 Eronini Umez-Eronini, SYSTEM DYNAMICS AND CONTROL,
`Brooks/Cole Publishing Co. (1999), pp. 10-13.
`
`Ex. 2007 Robert C. Weyrick, FUNDAMENTALS OF AUTOMATIC CONTROL,
`McGraw-Hill Book Company (1975), pp. 10-13.
`
`Ex. 2008 Chiang et al., U.S. Patent 6,398,929.
`
`
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` v
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`

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`I. INTRODUCTION
`All of the challenged claims are patentable over Wang and Kudryavtsev. The
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`IPR2014-00807
`U.S. Patent No. 7,604,716
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`‘716 patent requires generating a strongly-ionized plasma without developing an
`
`electrical breakdown condition in a chamber.1 Wang, however, merely describes
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`techniques for reducing, but not eliminating, electrical breakdown conditions such
`
`as arcing. The two are not the same. Kudryavtsev reports on “ionization relaxation”
`
`in a plasma when an external electric field is suddenly increased,2 but describes
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`experiments with an apparatus that does not include a magnetic field3 and, that are
`
`consistent with a flash caused by electrical breakdown, and very likely, arcing.4
`
`Thus, the combination of Wang and Kudryavtsev would not suggest supplying an
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`electrical pulse across the weakly-ionized plasma that excites atoms in the weakly-
`
`ionized plasma, thereby generating a strongly-ionized plasma without developing
`
`an electrical breakdown condition in the chamber,” as recited in independent claim
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`14 or “generating an electric field that excites atoms in the weakly-ionized plasma,
`
`1 Ex. 1201 at 21:9-11 (claim 14) (emphasis added); 22:13-15 (claim 26) (emphasis
`
`added).
`
`2 Ex. 1205 at p. 30, left col, ¶ 1.
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`3 Ex. 2004 at ¶ 73.
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`4 Id. at ¶ 75.
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`thereby forming a strongly-ionized plasma without developing an electrical
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`IPR2014-00807
`U.S. Patent No. 7,604,716
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`breakdown condition,” as recited in independent claim 26.5
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`
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`Wang describes applying DC power pulses to a plasma when sputtering
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`material from a target, but fails to teach or suggest controlling voltage during such
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`activities or when generating a high-density plasma. In fact, Wang does not explain
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`any electrodynamics of high-density plasmas.6 Control of power (as in Wang) is
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`very different from controlling voltage,7 and even Wang acknowledges this
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`distinction.8 Thus, unlike the ‘716 patent, in which the rise time of the electric field
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`is chosen to increase an ionization rate of excited atoms in a weakly-ionized
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`plasma to generate a strongly-ionized plasma,9 Wang discloses a very different
`
`approach to achieving a high density plasma.10
`
`
`5 Id. at ¶ 105.
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`6 Id. at ¶¶ 12, 71.
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`7 Id. at ¶¶ 58-62.
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`8 Ex. 1204 at 5:52-54 (“Where chamber impedance is changing, the power pulse
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`width is preferably specified rather than the current or voltage pulse widths.”).
`
`9 See, e.g., Ex. 1201 at 8:40-47; 22:29-32.
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`10 Ex. 2004 at ¶ 60.
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`2
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`“Wang’s elections in this regard have consequences.”11 The power pulses
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`IPR2014-00807
`U.S. Patent No. 7,604,716
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`will tend to produce an arc during the ignition of the plasma, as observed by Wang:
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`Plasma ignition, particularly in plasma sputter reactors, has a
`tendency to generate particles during the initial arcing, which
`may dislodge large particles from the target or chamber.12
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`This arcing is very problematic inasmuch as it leads to particle generation and can
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`damage the chamber and power equipment.13 Because Wang expects arcing when
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`his power pulses are used to ignite a plasma, the reference proposes only igniting
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`the plasma once and applying a fixed background power so that the plasma is
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`maintained in between power pulses.14
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`
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`Wang, however, does not solve the problem of arcing during plasma
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`initiation.15 Instead, Wang merely proposes reducing the amount of arcing by
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`keeping the plasma maintained so as not to require re-ignition with each pulse.16
`
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`11 Id. at ¶ 61.
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`12 Ex. 1204 at 7:3-6.
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`13 Id. at 7:1-12.
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`14 Id. at 7:13-31.
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`15 Ex. 2004 at ¶ 64.
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`16 Id.
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`3
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`Arcing is still possible when a pulse is applied across a pre-existing plasma,
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`IPR2014-00807
`U.S. Patent No. 7,604,716
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`particularly when there is a large, abrupt increase in the electric field as would
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`occur upon the sudden application of a power pulse, such as in the transition from
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`PB to PP shown in Wang’s Fig. 6.17 Wang does not discuss the risk of arcing in
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`connection with the application of power pulses, PP, or how to avoid it. Thus,
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`Wang does not teach or suggest that arcing could be avoided.18
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`The teachings of Kudryavtsev do not suggest any different result. As
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`discussed by Dr. Hartsough, a qualitative analysis reveals that Kudryavtsev’s flash
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`tube experiments had results consistent with arcing.19 Consequently, any
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`combination of Wang and Kudryavtsev would, at best, suggest techniques to
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`reduce, but not eliminate, arcing. It is also worth noting that Petitioners’ expert, Dr.
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`Kortshagen, testified that he understands the Board’s construction of the terms
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`“strongly ionized plasma” and “weakly ionized plasma” to require a range of
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`absolute magnitudes in peak density of ions, (namely, equal to or greater than 1012
`
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`17 Id. at ¶ 65.
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`18 Id.
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`19 Id. at ¶ 107 (discussing the rapid drop in voltage reported by Kudryavtsev—
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`characteristic of arcing).
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`and equal to or less than 109, respectively).20 Interestingly, this opinion conflicts
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`IPR2014-00807
`U.S. Patent No. 7,604,716
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`with that of Mr. Devito—Petitioner’s other expert—who requires that a strongly-
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`ionized plasma have a peak density of ions that is 3-4 orders of magnitude greater
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`than a weakly ionized plasma.21 But Dr. Kortshagen acknowledges that neither
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`Wang nor Kudryavtsev disclose a magnitude for the peak density of ions.22 Thus,
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`according to Dr. Kortshagen’s interpretation, it is impossible to conclude that
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`either Wang or Kudryavtsev teach a strongly ionized plasma at all.
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`
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`In contrast, the ‘716 patent demonstrates that arcing can be avoided, even on
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`plasma ignition, with proper control of electric field amplitude and rise time. This
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`is recited in the claims of the ‘716 patent, which require generating a strongly
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`ionized plasma without developing an electrical breakdown condition in the
`
`chamber.23 Inasmuch as the combination of Wang and Kudryavtsev fails to suggest
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`such features, the patentability of the challenged claims should be confirmed over
`
`these references.
`
`
`20 IPR2014-00818 Ex. 2010 at 44:13 – 58:12.
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`21 IPR2014-00799, Ex. 2014 at 169:10 – 170:25; 225:23 – 226:3.
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`22 IPR2014-00818 Ex. 2010 at 212:20-22; 216:2 – 217:21; 154:23 – 155:15.
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`23 Ex. 1201 at 21:9-11 (emphasis added); 22:13-15.
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`II. TECHNOLOGY BACKGROUND
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`IPR2014-00807
`U.S. Patent No. 7,604,716
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`The ‘716 patent relates to “[m]ethods and apparatus for generating a
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`strongly-ionized plasma.”24 Accordingly, we first review some fundamentals
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`concerning plasmas, and strongly-ionized (or high-density) plasmas in particular,
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`and then address Dr. Chistyakov’s particular solution for generating such a plasma.
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`
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`A.
`
`Plasma Fundamentals.
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`Plasma is a distinct state of matter characterized by a significant number of
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`electrically charged particles.25 In an ordinary gas, each atom or molecule contains
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`an equal number of positive and negative charges, so that each is electrically
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`“neutral.” When the atoms or molecules of the gas are subjected to heat or other
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`energy, they begin to lose electrons and are left with a positive charge. This
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`process is called ionization. When enough gas atoms or molecules have been
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`ionized such that the ions, together with the free electrons, significantly affect the
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`electrical characteristics of the substance it is said to be plasma. Although made up
`
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`24 Id. at Abstract.
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`25 Id. at 1:6-8.
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`of charged particles the plasma remains electrically neutral overall.26
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`IPR2014-00807
`U.S. Patent No. 7,604,716
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`Plasmas are used in a number of commercial and industrial applications,
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`including the manufacture of semiconductor devices. To that end, if a target (or an
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`object in its vicinity) is made electrically negative compared to the plasma,
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`positively charged ions in the plasma will be accelerated towards the target and a
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`number of different interactions may occur (see Figure 1, below).27
`
`(A)
`
`(B)
`
`(C)
`
`(D)
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`Plasma
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`Surface
`of
`Target
`
`FIG. 1
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`
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`Figure 1: Interactions at a target’s surface
`In Figure 1, an arriving ion is adsorbed onto the surface of the target at (A).
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`At (B), the incoming ion transfers some of its momentum to one of the target’s
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`surface atoms and causes it to be displaced. If the energy of the incoming ion is
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`sufficiently high, surface atoms of the target may be removed in a process referred
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`to as sputtering (shown in (C)). If the ion energy is even greater, then it may be
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`26 Ex. 2004 at ¶ 46.
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`27 Id. at ¶ 47.
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`implanted into the target (at (D)).28 Sputtering is often used to deposit layers of
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`IPR2014-00807
`U.S. Patent No. 7,604,716
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`material on a semiconductor substrate as part of an integrated circuit fabrication
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`process.29
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`
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`B.
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`Plasma Ignition
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`To ignite a plasma, a gas is introduced in a space between two electrodes,
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`for example in a tube or other container, and an electric field is applied between
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`the electrodes. An example of such an arrangement is shown in Figure 2.30
`
`Cathode
`
`Anode
`
`Tube
`
`Gas
`
`Electric Field
`
`+
`
`_
`
`Voltage
`Source
`Figure 2: Simplified plasma system
`Ions and electrons in the gas are accelerated towards the electrically negative
`
`
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`electrode (the “cathode”) and the electrically positive electrode (the “anode”),
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`28 Id. at ¶ 48.
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`29 Ex. 1204 at 1:10-15.
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`30 Ex. 2004 at ¶ 49.
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`respectively. As electrons collide with gas atoms, they produce new ions.31
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`U.S. Patent No. 7,604,716
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`When the ions are in close proximity to the cathode (e.g., on the order of a
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`few Angstroms), electrons can tunnel from the cathode, neutralizing the ions and
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`releasing energy. If sufficient energy is transferred to a surface electron at the
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`cathode, “secondary electrons” are emitted into the gas. The secondary electrons
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`are accelerated towards the anode, and when they collide with gas atoms they
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`generate new ions and free electrons. The process of ionization proceeds in this
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`fashion; and, if the applied power is sufficiently high, a plasma is created.32
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`
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`C. High-Density Plasmas
`
`The ‘716 patent is particularly concerned with high-density plasmas, for
`
`example, plasmas having a density greater than 1012 cm-3.33 Magnetron reactors
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`develop high-density plasmas using a magnetic field configured parallel to a target
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`surface to constrain the secondary electrons. The ions also concentrate in the same
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`region, maintaining the quasi-electrical neutrality of the plasma.34 This trapping of
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`31 Id.
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`32 Id. at ¶ 50.
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`33 See, e.g., Ex. 1201 at 21:45-7.
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`34 Id. at 3:13-28.
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`electrons and ions creates a dense plasma.35
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`IPR2014-00807
`U.S. Patent No. 7,604,716
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`Conventional magnetron systems suffer from undesirable, non-uniform
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`erosion or wear of the target that results in poor target utilization.36 To address
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`such problems, researchers tried increasing the applied power and later pulsing the
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`applied power. However, increasing the applied power increased “the probability
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`of generating an electrical breakdown condition leading to an undesirable electrical
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`discharge (an electrical arc) in the chamber . . . .”37 Even with the pulsed approach,
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`“very large power pulses can still result in undesirable electrical discharges
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`regardless of their duration.”38
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`
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`III. THE ‘716 PATENT
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`To overcome some of the deficiencies of the prior art, Dr. Chistyakov
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`invented a plasma processing apparatus and corresponding method in which:
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`An ionization source generates a weakly-ionized plasma
`proximate to the cathode. A power supply produces an electric
`
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`35 Ex. 2004 at ¶ 51.
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`36 Ex. 1201 at 3:29-31.
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`37 Id. at 3:38-41.
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`38 Id. at 3:50-52; and see Ex. 2004 at ¶¶ 52-54.
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`IPR2014-00807
`U.S. Patent No. 7,604,716
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`field in the gap between the anode and the cathode. The electric
`field generates excited atoms in the weakly-ionized plasma and
`generates secondary electrons from the cathode. The secondary
`electrons ionize the excited atoms, thereby creating a strongly-
`ionized plasma.39
`
`***
`
`Forming the weakly-ionized or pre-ionized plasma [ ]
`substantially eliminates the probability of establishing a
`breakdown condition in the chamber when high-power pulses
`are applied between the cathode [ ] and the anode [ ]. The
`probability of establishing a breakdown condition is
`substantially eliminated because the weakly-ionized plasma [ ]
`has a low-level of ionization that provides electrical
`conductivity through the plasma. This conductivity
`substantially prevents the setup of a breakdown condition,
`even when high power is applied to the plasma.40
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`As illustrated in Fig. 2A of the ‘716 patent, Dr. Chistyakov’s plasma
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`processing apparatus includes a cathode 204.41 An anode 216 is positioned “so as
`
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`39 Ex. 1201 at Abstract.
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`40 Id. at 4:16-25 (emphasis added).
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`41 Id. at 3:63-64.
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`to form a gap 220 between the anode 216 and the cathode 204 that is sufficient to
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`allow current to flow through a region 222 between the anode 216 and the cathode
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`204. . . . The gap 220 and the total volume of the region 222 are parameters in the
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`ionization process . . . .”42
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`
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`“[O]nce the weakly-ionized plasma 232 is formed, the pulsed power supply 202
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`generates high-power pulses between the cathode 204 and the anode 216 (FIG.
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`2C).”43
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`42 Id. at 4:30-39.
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`43 Id. at 6:51-53.
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`IPR2014-00807
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`“The high-power pulses generate a strong electric field 236 between the cathode
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`204 and the anode 216. . . . [and] generate a highly-ionized or a strongly-ionized
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`plasma 238 from the weakly-ionized plasma 232 . . . .”44 The strongly-ionized
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`plasma is also referred to as a high-density plasma.45
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`The challenged claims are all directed to generating a strongly-ionized
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`plasma using the multi-stage ionization described above. In particular, the claims
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`require generating a strongly-ionized plasma without developing an electrical
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`breakdown condition in a chamber.46
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`
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`44 Id. at 7:3-18.
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`45 Id. at 7:18-19.
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`46 Id. at 20:23-27; 22:47-50 (emphasis added).
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`13
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`IV. ARGUMENT.
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`IPR2014-00807
`U.S. Patent No. 7,604,716
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`In this proceeding, claims 14-18 and 25-32 are alleged to be unpatentable
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`under 35 U.S.C. § 103 as obvious in view of the combination of Wang and
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`Kudryavtsev. However, Petitioners cannot prevail on this proposed ground of
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`rejection because neither Wang nor Kudryavtsev, whether considered separately or
`
`in combination, teach or suggest generating a strongly-ionized plasma without
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`developing an electrical breakdown condition in a chamber as required by the
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`challenged claims. Accordingly, the patentability of the challenged claims should
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`be confirmed.
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`A party seeking to invalidate a patent claim as obvious must demonstrate
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`that a “skilled artisan would have been motivated to combine the teachings of the
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`prior art references to achieve the claimed invention, and that the skilled artisan
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`would have had a reasonable expectation of success in doing so.”47 This
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`47 See Proctor & Gamble Co. v. Teva Pharm. USA, Inc., 566 F.3d 989, 995 (Fed.
`
`Cir. 2009) (“To decide whether risedronate was obvious in light of the prior art, a
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`court must determine whether, at the time of invention, a person having ordinary
`
`skill in the art would have had ‘reason to attempt to make the composition’ known
`
`as risedronate and ‘a reasonable expectation of success in doing so.’”) (emphasis
`
`added).
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`determination is one that must be made at the time the invention was made.48 This
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`U.S. Patent No. 7,604,716
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`temporal requirement prevents the “forbidden use of hindsight.”49 Furthermore,
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`rejections for obviousness cannot be sustained by mere conclusory statements.50
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`“Petitioner[s] must show some reason why a person of ordinary skill in the art
`
`would have thought to combine particular available elements of knowledge, as
`
`evidenced by the prior art, to reach the claimed invention.”51 Inventions are often
`
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`48 Id.
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`49 See Mintz v. Dietz & Watson, Inc., 679 F.3d 1372, 1379 (Fed. Cir. 2012)
`
`(“Indeed, where the invention is less technologically complex, the need for
`
`Graham findings can be important to ward against falling into the forbidden use of
`
`hindsight.”).
`
`50 KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 418 (2007) (“[R]ejections on
`
`obviousness grounds cannot be sustained by mere conclusory statements; instead,
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`there must be some articulated reasoning with some rational underpinning to
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`support the legal conclusion of obviousness”).
`
`51 Heart Failure Technologies, LLC v. Cardiokinetix, Inc., IPR2013-00183, Paper
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`12 at p. 9 (P.T.A.B. July 31, 2013) (citing KSR, 550 U.S. at 418) (emphasis in
`
`original).
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`deemed nonobvious (and thus patentable) even when all of the claim elements are
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`IPR2014-00807
`U.S. Patent No. 7,604,716
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`individually found in the prior art because an “invention may be a combination of
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`old elements.”52 The motivation to combine inquiry focuses heavily on “scope and
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`content of the prior art” and the “level of ordinary skill in the pertinent art” aspects
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`of the Graham factors.53 Accordingly, we begin with a discussion of the references
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`at issue in this proceeding.
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`
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`A. Wang.
`Wang discusses “[a] pulsed magnetron sputter reactor [with] a high plasma
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`density.”54 In this reactor, “narrow pulses of negative DC power” are used to
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`sputter material from a target.55 In one example, Wang indicates that the pulses are
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`52 Cross Med. Prods., Inc. v. Medtronic Sofamor Danek, Inc., 424 F.3d 1293, 1321
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`(Fed. Cir. 2005).
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`53 Alza Corp. v. Mylan Labs., Inc., 464 F.3d 1286, 1290 (Fed. Cir. 2006) (“We
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`further explained that the ‘motivation to combine’ requirement ‘[e]ntails
`
`consideration of both the ‘scope and content of the prior art’ and ‘level of ordinary
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`skill in the pertinent art’ aspects of the Graham test.’”).
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`54 Ex. 1204 at 3:16-22.
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`55 Id. at 4:33-34.
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`U.S. Patent No. 7,604,716
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`applied to both ignite the plasma and maintain it,56 while in another example Wang
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`describes maintaining the plasma using a background power level with the pulses
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`applying a much greater peak power to increase the density of the plasma.57 In both
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`examples it is the power applied to a cathode target that is driven to a prescribed
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`level, not voltage.58
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`“This is not merely a difference in semantics.”59 Wang acknowledges there
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`is a substantive difference between controlling power and controlling voltage, and
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`chooses to control power parameters rather than those of current or voltage:
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`Where chamber impedance is changing, the power pulse width
`is preferably specified rather than the current or voltage pulse
`widths.60
`
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`56 Id. at 5:29-30.
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`57 Id. at 7:13-30.
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`58 Id. at 5:18-20; 7:13-30; and see 5:52-54 (“Where chamber impedance is
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`changing, the power pulse width is preferably specified rather than the current or
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`voltage pulse widths.”); and see Ex. 2004 at ¶ 58.
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`59 Ex. 2004 at ¶ 60.
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`60 Ex. 1204 at 5:52-54.
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`Thus, unlike the ‘716 patent, in which the rise time of the electric field is chosen to
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`increase an ionization rate of excited atoms in a weakly-ionized plasma to generate
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`a strongly-ionized plasma,61 Wang discloses a very different approach to achieving
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`a high density plasma.62
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`“[W]hen it comes to manipulating plasma density, configuring a power
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`supply to generate electrode power pulses can yield substantially different results
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`than configuring a power supply to generate voltage pulses with amplitude and rise
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`times.”63 Power pulses are the product of voltage and current. Therefore, to
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`maintain a constant power in the presence of a varying impedance (as in the case of
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`a weakly ionized plasma being transformed to a strongly ionized plasma), voltage
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`and current can vary significantly.64 A power supply will drive the voltage
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`extremely high when the current is near zero (e.g., before plasma ignition or when
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`the plasma density is low),65 producing an arc:
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`61 See, e.g., Ex. 1201 at 8:40-47; 22:29-32.
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`62 Ex. 2004 at ¶ 60.
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`63 Ex. 2004 at ¶ 61.
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`64 Id.
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`65 Id.; Ex. 1204 at 5:32-33.
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`Plasma ignition, particularly in plasma sputter reactors, has a
`tendency to generate particles during the initial arcing, which
`may dislodge large particles from the target or chamber.66
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`Indeed, in referring to the embodiment shown in Fig. 4, Wang admits that arcs
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`result when a power pulse ignites a plasma.
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`“Also, in this embodiment, each pulse 82 needs to ignite the
`plasma and maintain it. The effective chamber impedance
`dramatically changes between these two phases. A typical
`pulsed power supply will output relatively high voltage and
`almost no current in the ignition phase and a lower voltage and
`substantial current in the maintenance phase.”67
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`In a effort to reduce arcing, Wang proposes a Fig. 6 embodiment in which a
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`fixed background power is applied so that the plasma is maintained (and need not
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`be re-ignited) in between power pulses:
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`Accordingly, it is advantageous to use a target power waveform
`illustrated in FIG. 6 in which the target is maintained at a
`background power level PB between pulses 96 rising to a peak
`level PP corresponding to that contemplated in FIG. 4. The
`background level PB is chosen to exceed the minimum power
`
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`66 Ex. 1204 at 7:3-6.
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`67 Id. at 5:28-34; Ex. 2004 at ¶¶ 62-63.
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`necessary to support a plasma in the chamber at the operational
`pressure. Preferably, the peak power PP is at least 10 times the
`background power PB, more preferably at least 100 times, and
`most preferably 1000 times to achieve the greatest effect of the
`invention. A background power PB of 1 kW will typically be
`sufficient to support a plasma with the torpedo magnetron and a
`200 mm wafer although with little if any actual sputter
`deposition. As a result, once the plasma has been ignited at the
`beginning of sputtering prior to the illustrated waveform, no
`more plasma ignition occurs. Instead, the application of the
`high peak power PP instead quickly causes the already existing
`plasma to spread and increases the density of the plasma.68
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`This embodiment does not, however, solve the problem of arcing during
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`plasma initiation.69 Nor does Wang’s use of pre-ionization eliminate arcing during
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`application of the power pulses, it merely reduces the likelihood of same.70 Arcing
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`is still possible when a pulse is applied across a pre-existing plasma, particularly
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`when there is a large, abrupt increase in the electric field as would occur upon the
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`sudden application of a power pulse, such as in the transition from Wang's PB to
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`68 Ex. 1204 at 7:13-31.
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`69 Ex. 2004 at ¶ 64.
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`70 Id. at ¶ 65.
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`PP.71 Thus, Wang does not teach or suggest generating a strongly-ionized plasma
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`IPR2014-00807
`U.S. Patent No. 7,604,716
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`without developing an electrical breakdown condition in the chamber.72
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