Trials@uspto.gov
`571-272-7822
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` Paper No. 34
` Entered: June 6, 2018
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`
`UNITED STATES PATENT AND TRADEMARK OFFICE
`____________
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`____________
`
`MICRON TECHNOLOGY, INC.,
`INTEL CORPORATION, GLOBALFOUNDRIES U.S., INC., and
`SAMSUNG ELECTRONICS COMPANY, LTD.,
`Petitioner,
`
`v.
`
`DANIEL L. FLAMM,
`Patent Owner.
`____________
`
`Case IPR2017-003921
`Patent 5,711,849
`____________
`
`
`Before CHRISTOPHER L. CRUMBLEY, JO-ANNE M. KOKOSKI, and
`KIMBERLY McGRAW, Administrative Patent Judges.
`
`KOKOSKI, Administrative Patent Judge.
`
`
`
`FINAL WRITTEN DECISION
`35 U.S.C. § 318(a) and 37 C.F.R. §42.73
`
`
`1 Samsung Electronics Company, Ltd. was joined as a party to these
`proceedings via a Motion for Joinder in IPR2017-01747.
`
`
`571-272-7822
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`
`
`
`
`
` Paper No. 34
` Entered: June 6, 2018
`
`
`
`UNITED STATES PATENT AND TRADEMARK OFFICE
`____________
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`____________
`
`MICRON TECHNOLOGY, INC.,
`INTEL CORPORATION, GLOBALFOUNDRIES U.S., INC., and
`SAMSUNG ELECTRONICS COMPANY, LTD.,
`Petitioner,
`
`v.
`
`DANIEL L. FLAMM,
`Patent Owner.
`____________
`
`Case IPR2017-003921
`Patent 5,711,849
`____________
`
`
`Before CHRISTOPHER L. CRUMBLEY, JO-ANNE M. KOKOSKI, and
`KIMBERLY McGRAW, Administrative Patent Judges.
`
`KOKOSKI, Administrative Patent Judge.
`
`
`
`FINAL WRITTEN DECISION
`35 U.S.C. § 318(a) and 37 C.F.R. §42.73
`
`
`1 Samsung Electronics Company, Ltd. was joined as a party to these
`proceedings via a Motion for Joinder in IPR2017-01747.
`
`
`
`IPR2017-00392
`Patent 5,711,849
`
`
`I. INTRODUCTION
`We have jurisdiction to conduct this inter partes review under
`35 U.S.C. § 6, and this Final Written Decision is issued pursuant to
`35 U.S.C. § 318(a) and 37 C.F.R. § 42.73. For the reasons that follow, we
`determine that Petitioner has shown by a preponderance of the evidence that
`claims 1–29 of U.S. Patent No. 5,711,849 (“the ’849 patent,” Ex. 1001) are
`unpatentable.
`A.
`Procedural History
`Micron Technology, Inc., Intel Corporation, and
`GLOBALFOUNDRIES U.S., Inc. (collectively, “the Micron Petitioners”)2
`filed a Petition (“Pet.”) to institute an inter partes review of claims 1–29 of
`the ’849 patent based on the following grounds:
`References
`Basis
`Challenged Claims
`Alkire3 and Kao4
`§ 103
`1–29
`
`Alkire, Kao, and Flamm5
`
`§ 103
`
`1–29
`
`
`2 On September 15, 2017, we granted the Motion for Joinder filed by
`Samsung Electronics Company, Ltd. (“Samsung”) in IPR2017-01747, and
`authorized Samsung to participate in this proceeding only on a limited basis.
`See Paper 13. We refer to Micron Technology, Inc., Intel Corporation,
`GLOBALFOUNDRIES U.S., Inc., and Samsung collectively as “Petitioner”
`throughout this Decision.
`3 Transient Behavior during Film Removal in Diffusion-Controlled Plasma
`Etching, J. Electrochem. Soc.: Solid-State Science and Technology,
`Vol. 132, No. 3 (1985) 648–656 (Ex. 1005).
`4 Analysis of Nonuniformities in the Plasma Etching of Silicon with CF4/O2,
`J. Electrochemical Soc., Vol. 137, No. 3 (1990) 954–960 (Ex. 1006).
`5 The Reaction of Fluorine Atoms with Silicon, J. Appl. Phys., Vol. 52, No. 5
`(1981) 3633–3639 (Ex. 1007).
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`Paper 1, 5–6. Daniel L. Flamm (“Patent Owner”) filed a Preliminary
`Response (“Prelim. Resp.”). Paper 9. Pursuant to 35 U.S.C. § 314(a), we
`instituted an inter partes review of claims 1–29 based on our determination
`that the information presented in the Petition demonstrated a reasonable
`likelihood that Petitioner would prevail on its challenge that at least one of
`the challenged claims is unpatentable under 35 U.S.C. § 103 as obvious over
`the combined teachings of Alkire and Kao. Paper 10 (“Dec. on Inst.”), 19.
`We subsequently modified our institution decision to include “all of the
`grounds presented in the Petition.” Paper 32, 2.
`After institution of trial, Patent Owner filed a Patent Owner Response
`(Paper 12, “PO Resp.”), and Petitioner filed a Reply (Paper 14, “Reply”).
`Petitioner relies on the Declaration of Dr. David Graves (“the Graves
`Declaration,” Ex. 1003) and the Reply Declaration of Dr. David Graves
`(“the Graves Reply Declaration,” Ex. 1024). Patent Owner relies on the
`Declaration of Daniel L. Flamm (“the Flamm Declaration,” Ex. 2003). An
`oral hearing was held on March 7, 2018. A transcript of the hearing is
`included in the record. Paper 31.
`B.
`Related Proceedings
`The parties indicate that the ’849 patent is at issue in five related
`patent infringement actions. Pet. 4; Paper 7, 2. The ’849 patent previously
`was the subject of IPR2016-00466 (filed by Lam Research Corp., institution
`denied on July 19, 2016), and currently is the subject of IPR2017-00406,
`also filed by the Micron Petitioners (and joined by Samsung). Pet. 4.
`C.
`The ’849 Patent
`The ’849 patent, titled “Process Optimization in Gas Phase Dry
`Etching,” is directed to “a plasma etching method that includes determining
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`a reaction rate coefficient based upon etch profile data.” Ex. 1001, 1:51–53.
`The method “includes steps of providing a plasma etching apparatus having
`a substrate therein[,]” where the substrate has a film overlaying the top
`surface, and the film has a top film surface. Id. at 1:59–63. It “also includes
`chemically etching the top film surface to define an etching profile on the
`film, and defining etch rate data which includes an etch rate and a spatial
`coordinate from an etching profile.” Id. at 1:63–67. Steps of extracting a
`reaction rate constant from the etch rate data, and using the reaction rate
`constant to adjust the plasma etching apparatus are also described. Id. at
`1:67–2:2. According to the ’849 patent, the method “provides for an easy
`and cost effective way to select appropriate etching parameters such as
`reactor dimensions, temperature, pressure, radio frequency (rf) power, flow
`rate and the like by way of the etch profile data.” Id. at 1:53–57.
`Figure 1A of the ’849 patent is reproduced below:
`
`
`Figure 1A is an example of an etched substrate. Id. at 3:66–67. Substrate 21
`includes bottom surface 23, sides 25, and top surface film 27, and is defined
`in spatial coordinates z and r. Id. at 3:67–4:2. “[T]op surface film [27]
`includes a convex region, or etching profile.” Id. at 4:3–4. “The etching
`profile occurs by way of different etch rates along the r-direction of
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`[substrate 21], corresponding to different etchant species concentrations.”
`Id. at 4:4–6. Concentration profile no(r,z) shows that “the greatest
`concentration of reactant species exists at the outer periphery of [] top
`surface film [27].” Id. at 4:6–9.
`The ’849 patent describes an embodiment of a method of extracting
`an etch rate constant in which a substrate with an overlying film is placed
`into a plasma etching apparatus, and the plasma etching step occurs at
`constant pressure, and, preferably, isothermally. Id. at 5:11–19. Plasma
`etching of the film stops before etching into an etch stop layer underneath
`the overlying film “[in order] to define a ‘clean’ etching profile.” Id. at
`5:24–26. The plasma etching step produces an etching profile, which
`“converts into a relative etch rate, relative concentration ratio, a relative etch
`depth and the like at selected spatial coordinates.” Id. at 5:28–32.
`Using x-y-z coordinates, the relative etch rate is in the z-direction, and
`x-y are the spatial coordinates. Id. at 5:38–40. “The etching profile is
`thereby characterized as a relative etch rate u, [an] x-location, and a y-
`location u, (x, y),” and an array of data points in the x-y coordinates define
`the etching profile. Id. at 5:40–41, 45–47. An etch constant over diffusivity
`(kvo/D) and an etch rate at the substrate edge is then calculated, where “[t]he
`etch constant over diffusivity correlates with data points representing the
`etch rate profile.” Id. at 5:62–65. After the etch rate constant kvo is
`extracted, the surface reaction rate constant ks can be determined using the
`formula ks = (kvo)dgap, where dgap is the space above the substrate, between
`the substrate and the adjacent substrate. Id. at 3:35–36, 6:58–62, 9:27–29,
`Fig 7.
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`Claims 1, 10, 20, 22, and 26 are the challenged independent claims.
`Claim 1 is representative, and is reproduced below.
`1. A device fabrication method comprising the steps of:
`providing a plasma etching apparatus comprising a substrate
`therein, said substrate comprising a top surface and a film
`overlying said top surface, said film comprising a top film
`surface;
`etching said top film surface to define a relatively non-uniform
`etching profile on said film, and defining etch rate data
`comprising an etch rate and a spatial coordinate which
`defines a position within said relatively non-uniform
`etching profile on said substrate, said etching comprising
`a reaction between a gas phase etchant and said film; and
`extracting a surface reaction rate constant from said etch rate
`data, and using said surface reaction rate constant in the
`fabrication of a device.
`Ex. 1001, 17:35–50.
`
`A.
`
`II. ANALYSIS
`Level of Ordinary Skill in the Art
`Petitioner argues that a person of ordinary skill in the art at the time of
`the ’849 patent would have had “a Bachelor of Science degree in chemical
`engineering, electrical engineering, material science, chemistry, or physics
`or a closely related field, along with at least 3–4 years of experience in the
`development of plasma etching or chemical vapor deposition.” Pet. 19.
`Petitioner further argues that a person with a master’s degree “would require
`2–3 years of experience in the development of plasma etching or chemical
`vapor deposition,” and a person with a Ph.D. “would not require additional
`experience.” Id. (citing Ex. 1003 ¶ 73). Patent Owner does not dispute
`Petitioner’s assessment in its Response.
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`Petitioner’s assessment appears consistent with the level of ordinary
`skill in the art at the time of the invention as reflected in the prior art in this
`proceeding. See Okajima v. Bourdeau, 261 F.3d 1350, 1355 (Fed. Cir.
`2001) (explaining that specific findings regarding ordinary skill level are not
`required “where the prior art itself reflects an appropriate level and a need
`for testimony is not shown” (quoting Litton Indus. Prods., Inc. v. Solid State
`Sys. Corp., 755 F.2d 158, 163 (Fed. Cir. 1985))). Accordingly, we adopt
`Petitioner’s assessment of the level of ordinary skill in the art.
`Claim Interpretation
`B.
`The ’849 patent has expired. Ex. 1001, [22] (application filed on May
`3, 1995); see Pet. 15. For claims of an expired patent, the Board’s claim
`interpretation is similar to that of a district court, i.e., consistent with Phillips
`v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (en banc). See In re Rambus,
`Inc., 694 F.3d 42, 46 (Fed. Cir. 2012). Under the Phillips standard, claim
`terms are given their ordinary and customary meaning as would be
`understood by a person of ordinary skill in the art at the time of the
`invention, and in the context of the entire patent disclosure and prosecution
`history. Phillips, 415 F.3d at 1312–14. Only those terms in controversy
`need to be construed, and only to the extent necessary to resolve the
`controversy. See Nidec Motor Corp. v. Zhongshan Broad Ocean Motor Co.,
`868 F.3d 1013, 1017 (Fed. Cir. 2017) (“we need only construe terms ‘that
`are in controversy, and only to the extent necessary to resolve the
`controversy’”) (quoting Vivid Techs., Inc. v. Am. Sci. & Eng’g, Inc.,
`200 F.3d 795, 803 (Fed. Cir. 1999)).
`For purposes of the Decision on Institution, we interpreted “surface
`reaction rate constant” as set forth in claims 1, 5, 10, 14, 20, 22, 26, 27, and
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`29 to mean “a temperature-dependent reaction rate constant for the chemical
`reaction between a gas phase etchant and the surface of an etchable
`material.” Dec. on Inst. 7. The parties do not contest our interpretation of
`this term, and we see no reason to modify it in light of the record developed
`at trial.
`C.
`Principles of Law
`To prevail on its challenges to the patentability of the claims, a
`petitioner must establish facts supporting its challenge by a preponderance
`of the evidence. 35 U.S.C. § 316(e); 37 C.F.R. § 42.1(d). “In an [inter
`partes review], the petitioner has the burden from the onset to show with
`particularity why the patent it challenges is unpatentable.” Harmonic Inc. v.
`Avid Tech., Inc., 815 F.3d 1356, 1363 (Fed Cir. 2016) (citing 35 U.S.C.
`§ 312(a)(3) (requiring inter partes review petitions to identify “with
`particularity . . . the evidence that supports the grounds for the challenge to
`each claim”)). This burden of persuasion never shifts to the patent owner.
`See Dynamic Drinkware, LLC v. Nat’l Graphics, Inc., 800 F.3d 1375, 1378–
`79 (Fed. Cir. 2015) (discussing the burdens of persuasion and production in
`inter partes review).
`A claim is unpatentable under 35 U.S.C. § 103 if the differences
`between the subject matter sought to be patented and the prior art are such
`that the subject matter as a whole would have been obvious to a person
`having ordinary skill in the art to which the subject matter pertains. KSR
`Int’l Co. v. Teleflex, Inc., 550 U.S. 398, 406 (2007). The question of
`obviousness is resolved on the basis of underlying factual determinations,
`including (1) the scope and content of the prior art; (2) any differences
`between the claimed subject matter and the prior art; (3) the level of ordinary
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`skill in the art; and (4) objective evidence of nonobviousness. See Graham
`v. John Deere Co., 383 U.S. 1, 17–18 (1966).
`A patent claim “is not proved obvious merely by demonstrating that
`each of its elements was, independently, known in the prior art.” KSR, 550
`U.S. at 418. An obviousness determination requires finding “both ‘that a
`skilled artisan would have been motivated to combine the teachings of the
`prior art references to achieve the claimed invention, and that the skilled
`artisan would have had a reasonable expectation of success in doing so.’”
`Intelligent Bio-Sys., Inc. v. Illumina Cambridge Ltd., 821 F.3d 1359, 1367–
`68 (Fed. Cir. 2016) (citation omitted); see KSR, 550 U.S. at 418 (for an
`obviousness analysis, “it can be important to identify a reason that would
`have prompted a person of ordinary skill in the relevant field to combine the
`elements in the way the claimed new invention does”). A reason to combine
`or modify the prior art may be found explicitly or implicitly in market
`forces, design incentives, the “interrelated teachings of multiple patents,”
`“any need or problem known in the field of endeavor at the time of invention
`and addressed by the patent,” and “the background knowledge, creativity,
`and common sense of the person of ordinary skill.” Perfect Web Techs., Inc.
`v. Info USA, Inc., 587 F.3d 1324, 1329 (Fed. Cir. 2009) (quoting KSR, 550
`U.S. at 418–21).
`D. Overview of the Prior Art
`1.
`Overview of Alkire
`Alkire is directed to the formulation of a mathematical model “to
`analyze transient behavior during film removal from closely spaced wafers
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`in a barrel plasma etching reactor.” Ex. 1005, 1.6 “The analysis relates the
`effect of geometric and operating variables to process characteristics such as
`etch uniformity, over-etch exposure, and throughput.” Id. “Regions of
`operating conditions that permit etch uniformity within specified tolerances
`are found, and optimum settings for inter-wafer spacing and reactor pressure
`to achieve maximum throughput are calculated.” Id. Alkire teaches that
`“[e]tch uniformity and throughput are of particular importance in any plasma
`etching process,” and that “[p]arameters that affect uniformity and
`throughput include RF power input, chamber pressure, gas flow rate and
`distribution, wafer spacing, wafer diameter, and temperature.” Id. at 1–2.
`Alkire Figure 2 is reproduced below.
`
`
`Figure 2 is a schematic of the radially symmetric region between two
`successive wafers that are facing each other. Id. at 2. Before etching begins,
`a uniform-thickness film exists on the wafer surface. Id. “To an extent that
`
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`6 The cited page numbers in Ex. 1005 refer to the numbers added by
`Petitioner in the bottom right corner of the page.
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`depends upon operating conditions, the etch rate is highest on the periphery
`of the wafer,” and, therefore, film in this region clears first. Id. Figure 2
`illustrates this, showing that the “film has been cleared entirely from the
`outer portion of the wafer, while the inner region is yet to clear.” Id.
`Alkire makes several assumptions to “preserve the salient features of
`the system and also streamline the task of computation,” including that
`“[t]he spacing between the adjacent wafers is sufficiently smaller than the
`wafer radius so that significant concentration variations occur only in the
`radial direction,” “the etching reaction is first order” and “proceeds to
`completion at or near the film surface,” and “[t]he concentration of etchant
`at the wafer remains constant during the etch cycle.” Id. Alkire provides
`two governing equations: Equation [1] that gives “the thickness of etchable
`material left at a certain location and time,” and Equation [2] that is the
`conservation equation for the etching species, as set forth below.
`
`
`
`with the boundary conditions
`
`ℎ(𝑟𝑟,𝑡𝑡)=ℎ𝑜𝑜− �𝑘𝑘2𝑥𝑥 𝑐𝑐(𝑟𝑟,𝑡𝑡) 𝑑𝑑𝑡𝑡
`𝑡𝑡
` [1]
`𝑜𝑜
`𝐷𝐷 1𝑟𝑟 𝑑𝑑𝑑𝑑𝑟𝑟 �𝑟𝑟 𝑑𝑑𝑐𝑐𝑑𝑑𝑟𝑟�= 2𝑘𝑘2𝐿𝐿 𝑐𝑐+2𝑘𝑘1𝑐𝑐2[𝐴𝐴2]+ 𝑣𝑣𝑜𝑜𝑤𝑤2𝐿𝐿𝑐𝑐 [2]
`𝑐𝑐=𝑐𝑐𝑜𝑜 at 𝑟𝑟=𝑅𝑅𝑜𝑜
`𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑=0 at 𝑟𝑟=0
`
`Id. Alkire defines h0 as the initial film thickness (cm), k2 as the etch rate
`constant (cm/s), Χ as the moles of etchant species consumed per cm3 of film
`etched (mol/cm3), c as the etchant concentration (mol/cm3), h as the film
`thickness (cm), r as the radial position (cm), t as time (s), D as the etchant
`diffusivity (cm2/s), L as the wafer separation distance (cm), k1 as the volume
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`recombination reaction rate constant (cm6/(mol)2/s), A2 as the parent
`molecule, vo as the random thermal velocity of etchant species (cm/s), w as
`the wall recombination coefficient, c0 as the etchant concentration at the
`wafer edge (mol/cm3), and R0 as the wafer radius (cm). Id. at 8–9.
`Alkire then “rewrite[s] the governing equations in terms of
`dimensionless quantities” that it defines, resulting in dimensionless
`Equations [6] and [7]. Id. at 3. According to Alkire, “[b]y solving Eq. [6]
`and [7], the effect of process parameters (c0, P, D, k’s) and of geometric
`factors (L, R0) on etch uniformity, overetch exposure, and total etch time can
`be determined,” and, “[i]n particular, optimum conditions for high
`throughput can be identified.” Id. Alkire states that these “[d]imensionless
`groupings of system parameters were used to compile behavior and to reveal
`scale-up principles,” and that “[t]he model can be extended without much
`difficulty to handle more complex situations.” Id. at 8. Alkire concludes
`that “[t]he use of mathematical models can assist in organizing scientific
`concepts into strategies for engineering design.” Id.
`2.
`Overview of Kao
`Kao describes experimental and modeling work that “examine[s] the
`effect of reactor pressure, etchant gas flow rate, and wafer location on the
`uniformity of plasma etching silicon using CF4/O2 in a parallel-plate-radial
`flow reactor.” Ex. 1006, 1.7 Kao “presents the results of a series of
`experiments aimed at quantifying the dependencies of etch uniformity on
`process parameters,” and develops a quantitative model that “helps explain
`several trends in the data.” Id.
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`7 The cited page numbers in Ex. 1006 refer to the numbers added by
`Petitioner in the bottom right corner of the page.
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`Kao measured etch depths at various stages of the experimental
`process, including prior to etching (to measure the initial film thickness) and
`immediately after etching (to measure the amount of film removed), and
`calculated etch rates as etch depth divided by etch time. Id. at 2. Etch rate
`profiles were measured from the point closest to the reactor exit to the point
`closest to the reactor entrance, and plotted as (i) average absolute etch rate at
`any position across the wafer and (ii) etch rates normalized to the minimum
`etch rate over the wafer in order “to indicate the degree of nonuniformity
`across the wafer.” Id.
`Kao’s model “takes a simplified approach to the plasma etching
`system,” and “assume[s] that plasma etching occurs via three lumped
`reaction steps: (i) dissociation of etchant gas molecules by electron
`bombardment (or chemical reaction with free radicals),” “(ii) a surface
`reaction between the substrate atoms and the reactive etching species
`produced in the plasma, and (iii) chemically reactive species (free radicals)
`recombining to form a nonreactive species through loss reactions.” Id. at 3.
`“Designating k*d to be the rate constant for the dissociation of CF4, ke to the
`rate constant for the surface etching reaction, and kl to be the loss reaction
`rate constant,” Kao gives the rate of reaction in the gas phase for fluorine,
`CF4, and silicon, and the component continuity equations for CF4 and F. Id.
`at 4. Kao ultimately presents its model in dimensionless form in Equations
`[8a-b], which “were solved using the finite element program TWODEPEP.”
`Id. at 5.
`Kao explains that “[t]he unknown reaction rate constants, kl, kd, and ke
`were varied in each call to TWODEPEP to allow minimizing the error
`between the observed and the calculated etch rate.” Id. “The three runs
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`which varied flow rate (data of Fig. 3) were used to determine the set of
`three constants.” Id. Kao states that “[t]he agreement is good” between
`observed etch rates and predicted etch rates “at 60 and 80 sccm flow rates,
`with a small deviation observed at 100 sccm near the center of the wafer.”
`Id. Kao observes that “decreasing flow rate enhances the etch rate,” “higher
`pressures resulted in higher etch rates,” and “the location of the wafer has
`only a small effect on etch uniformity.” Id. at 6.
`Kao concludes that its experimental results “show a large degree of
`nonuniformity in etch rate when etching silicon with CF4/O2.” Id.
`According to Kao, “[a]n approximate kinetic model coupled with a radial
`flow reactor model shows promise in predicting the etch rate
`nonuniformities and the magnitude of the etch rate,” and “[r]ate parameters
`determined by best fitting the model to the experimental data are of
`reasonable magnitudes compared to those reported elsewhere.” Id. at 7.
`3.
`Overview of Flamm
`Flamm describes an investigation in which “the etching of silicon by
`F atoms and intensity of concomitant luminescence were measured as a
`function of temperature (223–403K) and F-atom concentration
`(nF = 1.6x1015 – 7.7x1015 cm-3).” Ex. 1007, 1.8 Flamm reports that the
`saturated intensity “was measured as a function of temperature,” and
`provides “a typical data set taken at constant pressure and mole fraction of F
`atoms (constant discharge power), which has been corrected for the effect of
`temperature on the gas-phase F-atom density.” Id. at 3. Flamm explains
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`8 The cited page numbers in Ex. 1007 refer to the numbers added by
`Petitioner in the bottom right corner of the page.
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`that “[t]he intensity is well described by an Arrhenius expression” using a
`factor that “corrects for the temperature dependencies of atom concentration
`and atom flux to the surface.” Id.
`Flamm also “shows the temperature dependence of etch rates
`similarly corrected for the effect of temperature on atom density,” where the
`“etch rates are described by the regression equation R(Si) = 2.91 ±
`0.20x10-12nFT1/2e-Eetch/kT.” Id. Flamm reports that “[w]ithin experimental
`error the etch rate and chemiluminescent intensity have the same activation
`energy.” Id. Flamm concludes that “[t]he present rates and activation
`energy are consistent with those reported for in situ etching of Si and SiO2 in
`F atoms containing plasmas at 0.3–0.5 Torr” and, consequently, “the F atom
`solid reaction alone can generally account for these data.” Id. at 6.
`E.
`Obviousness over Alkire and Kao
`Petitioner contends that the subject matter of claims 1–29 is
`unpatentable under 35 U.S.C. § 103(a) as having been obvious over the
`combined teachings of Alkire and Kao. Pet. 34–77; Reply 4–29. Petitioner
`relies on the Graves Declaration and the Graves Reply Declaration in
`support of its contentions. Id. Patent Owner disagrees with Petitioner’s
`assertions. PO Resp. 2–19, 21–32.
`1. Motivation to Combine Alkire and Kao
`Petitioner contends that a person having ordinary skill in the art
`(“PHOSITA”) “would have combined Alkire and Kao in order to improve
`the theoretical model of Alkire with the use of experimental data in order to
`test and validate Alkire’s theoretical model, as taught in Kao.” Pet. 30
`(citing Ex. 1003 ¶ 114). Petitioner contends that Kao discloses, “and a
`PHOSITA would have recognized, that Alkire provides a robust model for
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`the reaction between a gas phase etchant and a substrate film, but that no
`experimental data to support or inform that model was provided,” and that
`“[a] PHOSITA would have been motivated to improve the model disclosed
`in Alkire by using experimental data to provide independent confirmation of
`the accuracy of the model as taught in Kao.” Id. at 30–31 (citing Ex. 1006,
`1; Ex. 1003 ¶ 115). According to Petitioner, “a PHOSITA would have been
`motivated to combine the teachings of Kao with those of Alkire in order to
`increase the predictive capability of Alkire’s model to better drive process
`development and reactor design to improve throughput and yield while
`avoiding costly trial and error.” Id. at 31 (citing Ex. 1003 ¶ 116).
`Petitioner also contends that “both Alkire and Kao disclose the known
`technique of modeling a plasma etching reaction between a gas-phase and
`substrate,” and “Kao further teaches measuring the etch rate profile of the
`substrate and using that etch rate data to calculate a surface reaction rate
`constant by performing a best-fit calculation on the etch rate data.” Pet. 31
`(citing Ex. 1003 ¶ 117; Ex. 1006, 3–5). Petitioner contends that “Alkire and
`Kao are both directed to plasma etching reactors for manufacturing
`semiconductor devices and address non-uniformity in semiconductor plasma
`etching.” Id. at 32 (citing Ex. 1005, 1–2, Fig. 1; Ex. 1006, 1–2, Fig. 1;
`Ex. 1003 ¶ 119). Petitioner further contends that “Kao teaches that its
`experiments were intended to build upon the earlier work of Alkire in
`analyzing the use of a barrel plasma etcher to etch a film in an ashing
`model.” Id. (citing Ex. 1006, 1; Ex. 1003 ¶ 119).
`Patent Owner argues that “[i]t would not have been obvious for a
`PHOSITA to combine Alkire with the experimental measurement of reaction
`rate and the use of that data in modeling as taught by Kao.” PO Resp. 6.
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`Patent Owner argues that “Kao emphasizes solving his model for the radius
`of the reactor, which is completely different from the model of Alkire, which
`solves for the radius of the wafer.” Id. Patent Owner argues that “[t]he
`twelve distinct etch rate measurements plotted in Figures 8 through 11 of
`Kao are not symmetrical across the wafer” and a PHOSITA would not use
`these measurements “due to the lack of symmetry for analysis of a plasma
`etching model to the plasma etching techniques and model of Alkire.” Id. at
`7.
`
`Patent Owner further argues that “Alkire specifically teaches away
`from the use of ‘purely empirical programs of development’ (Ex. 1005 at 1),
`which would teach away from the use of the etch rate data disclosed by
`Kao.” PO Resp. 9. According to Patent Owner, “Alkire’s statement that
`‘purely empirical programs of development can be time consuming’ does
`criticize, discredit, or disparage the use of empirical data to improve the
`fabrication of a device.” Id. Patent Owner also argues that Kao
`“emphasizes that ‘the model predicts a larger effect of pressure on etch rate
`than observed,’ which confirms incompatibility to discredit or discourage
`investigation,” and “admits that ‘the pressure dependence of ki is unknown
`and further work is warranted’ tacitly acknowledging that a PHOSITA could
`not rely on his models or data and further discredits or discourages
`investigation.” Id. at 9–10 (internal citation omitted).
`Patent Owner additionally argues that “a PHOSITA would never use
`the actual experimental data or related techniques reported by Kao in
`combination with any modeling technique or with any other re[a]ctor design
`and related process” because “Kao was etching wafers in a tragically
`deficient geometry using a feed gas mixture known to generate a complex
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`product composition that shifts widely responsive to variations in flow,
`pressure, and electrical discharge parameters.” PO Resp. 14. Patent Owner
`argues that “Kao did not measure chemical composition or any products of
`his complex plasma chemistry, the identity, relative concentrations, and
`spatial distributions of species interacting with his silicon wafers were
`unknown,” and “[a]ccordingly, a PHOSITA could not combine the etching
`data from Kao with Alkire or any other reference in view of established
`knowledge that Kao’s chemistries and reactor design would yield a wide
`range of variation.” Id. at 16.
`Based on our review of the record, we find that Petitioner has
`established that a PHOSITA would have had reason to combine the
`teachings of Alkire and Kao to achieve the claimed subject matter. Alkire
`discloses that the mathematical model developed therein “represents a
`simplified view by virtue of several assumptions,” but “can serve as a basis
`for studying more complex systems.” Ex. 1005, 8. Alkire also states that
`“[e]xperimental work aimed at testing the model predictions is currently in
`progress in our laboratory.” Id. Kao identifies Alkire as one of “[s]everal
`papers [that] have been published which discuss the problem of etch
`nonuniformities,” noting that Alkire “examined the nonuniform stripping of
`photoresist with O2 in a barrel reactor,” which “results in a depletion of the
`etching species across the wafer, thus causing nonuniform etching.”
`Ex. 1006, 1. Kao goes on to present “the results of a series of experiments
`aimed at quantifying the dependencies of etch uniformity on process
`parameters.” Id. In this regard, we credit Dr. Graves’s testimony that
`[o]ne of ordinary skill in the art would have understood that one
`could, and would have been motivated to, improve the theoretical
`model of Alkire with the use of actual experimental data as
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`disclosed in Kao. Kao specifically discusses Alkire, and
`discloses that while Alkire provides a robust model for the
`reaction between a gas phase etchant and a substrate film, no
`experimental data to support or inform the model was provided.
`See Ex. 1006 at p. 1 (discussing the model of Alkire and
`recognizing that “only model results were given with no
`experimental data”). The use of actual experimental data to
`extract the surface reaction rate constant would provide
`independent confirmation of the accuracy of Alkire’s model. A
`person of ordinary skill in the art would have been motivated to
`test and validate the model of Alkire with actual data, as taught
`in Kao.
`Ex. 1003 ¶ 115.
`We have considered Patent Owner’s arguments to the contrary and do
`not agree with them for the following reasons. Patent Owner contends that
`Alkire and Kao solve for different radii using different models, i.e., Alkire
`solves for the radius of the wafer and Kao solves for the radius of the
`reactor. PO Resp. 6. Petitioner, however, shows that Kao’s Figure 8
`“teaches three sets of measurements (circles, squares, and triangles) taken at
`twelve distinct positions across each wafer.” Reply 18 (citing Ex. 1003
`¶ 143; Ex. 1006, 5). With respect to Figure 8, Kao explains that the data of
`Figure 3 “were used to determine the set of three constants,” and that
`Figure 8 shows “[o]bserved etch rates (data points) vs. predicted etch rates
`(lines) . . . for the single wafer case at three different flow rates.” Ex. 1006,
`5. Kao explains that the etch rate profiles shown in Figure 3 were the result
`of experiments
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