`
`DOCKET NO.: 2003195-00123US3 and US4
`Filed By: David L. Cavanaugh, Reg. No. 36,476
`Dominic E. Massa, Reg. No. 44,905
`Michael H. Smith, Reg. No. 71,190
`1875 Pennsylvania Ave. NW
`Washington, DC 20006
`Tel: (202) 663-6000
`Email: David.Cavanaugh@wilmerhale.com
`Dominic.Massa@wilmerhale.com
`MichaelH.Smith@wilmerhale.com
`
`UNITED STATES PATENT AND TRADEMARK OFFICE
`____________________________________________
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`____________________________________________
`
`
`TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.
`Petitioner
`
`v.
`
`GODO KAISHA IP BRIDGE 1
`Patent Owner.
`
`Case IPR2017-018431
`
`
`PETITIONER’S REPLY TO PATENT OWNER’S RESPONSE
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`
`
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`1 Case IPR2017-01844 has been consolidated with this proceeding.
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`
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`
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`Table of Contents
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`I.
`II.
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`III.
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`Page
`Introduction ...................................................................................................... 1
`Patent Owner Does Not Dispute Misra’s Thermally Grown Sidewall
`Embodiments Disclose the Claimed Protruding Gate ..................................... 4
`Patent Owner’s Construction of “Silicon Nitride Film” Applies an
`Unreasonable Interpretation of “Layer” .......................................................... 6
`IV. No POSITA Would Have Thought the Layer 20 and the Spacer 23 Were the
`Same Film ........................................................................................................ 9
`A.
`The Petition’s Showing is Confirmed by the Prosecution
`History ................................................................................................. 10
`Patent Owner Cannot Overcome the Overwhelming Evidence
`of Invalidity with its Unreasonable Interpretation of “Silicon
`Nitride Film” ....................................................................................... 19
`V. Misra’s Gate Protrudes Above the Parts of the Silicon Nitride Film ............ 25
`VI. Conclusion ..................................................................................................... 29
`
`
`B.
`
`i
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`
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`I.
`
`INTRODUCTION
`The Patent Owner’s Response (“Response”) confirms that the challenged
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`claims are unpatentable. With the exception of the “protruding gate” limitation
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`(“the gate electrode protrudes upward from a surface level of parts of the silicon
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`nitride film located at both side surfaces of the gate electrode”), Patent Owner
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`(“PO”) does not dispute that the instituted grounds expressly disclose every
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`limitation recited by the challenged claims of the ’501 patent.2 Nor does PO
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`dispute that the references would have been obvious to combine. Instead, PO
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`merely repeats the same arguments that it already raised in its Patent Owner’s
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`Preliminary Response (“POPR”3) that Misra does not disclose a gate that protrude
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`2 PO does not even dispute that the protruding gate limitation was known in the art.
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`In fact, PO actually cites Igarashi—the primary prior art reference in the instituted
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`grounds in related IPR2017-01841—to explain in this proceeding that the
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`advantages of the “protruding gate” were well-known. POPR, 32 (“[A] POSA
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`would have understood that … causing the gate electrode to protrude above the
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`silicon nitride … would advantageously reduce parasitic capacitance. Indeed,
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`Igarashi teaches this explicitly.”), 30-36; Response, 23-25; Ex. 2208, ¶¶45-50.
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`3 Unless otherwise specified with the “-01844” prefix, references to exhibits and
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`papers herein are to those filed in Case IPR2017-01843.
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`U.S. Patent 7,893,501
`IPR2017-01843
`Petitioner’s Reply to Patent Owner’s Response
`
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`above a silicon nitride film. These arguments were correctly rejected by the Board
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`in the Institution Decision (“DI”) and fail again here.
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`There is no dispute that Misra’s gate 28b protrudes above Misra’s silicon
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`nitride film 20, just as gate 6a protrudes above silicon nitride film 8a in the ’501
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`patent. Ex. 1232, ¶5.
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`
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`Petition, 40-42. Instead, PO argues gate 28b must also protrude above spacers 23.
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`As an initial matter, PO’s arguments fail because they incorrectly assume
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`that the spacers 23 are necessarily made of silicon nitride. This assumption is
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`wrong. Misra expressly states with regard to spacers 23 that the “nitride spacers
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`formed by deposition may be replaced or composited with a sidewall thermal
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`growth,” Ex. 1204, 6:54-58 (emphasis added), as Dr. Shanfield confirmed on
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`cross-examination when questioned about this language. Ex. 2210, 262:6-24. It is
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`therefore undisputed that Misra discloses the “protruding gate” limitation in the
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`U.S. Patent 7,893,501
`IPR2017-01843
`Petitioner’s Reply to Patent Owner’s Response
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`embodiments where spacers 23 are replaced with sidewall thermal growth. Ex.
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`1232, ¶6.
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`Moreover, PO’s arguments fail to rebut Petitioner’s additional showing that
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`Misra discloses the “protruding gate” limitation “regardless of whether spacers 23
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`are constructed out of silicon nitride.” Petition, 42. PO raises the same principal
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`arguments it raised in the POPR. Each argument was already rejected by the
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`Board and fails again here:
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` PO again incorrectly argues that the “silicon nitride film” includes
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`both the plasma enhanced nitride layer 20 and silicon nitride spacers
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`23. See e.g., Response, 45.
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` PO again incorrectly argues that Misra’s gate does not protrude above
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`the parts of the silicon nitride film closest to the gate, which it argues
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`are the silicon nitride spacers 23. See e.g., Response, 71.
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`Ex. 1232, ¶7.
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`As set forth in the Petition and confirmed below, the challenged claims of
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`the ’501 patent would have been obvious under the cited prior art references and,
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`accordingly, Petitioner respectfully requests that the Board cancel all challenged
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`claims.
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`U.S. Patent 7,893,501
`IPR2017-01843
`Petitioner’s Reply to Patent Owner’s Response
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`II.
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`PATENT OWNER DOES NOT DISPUTE MISRA’S THERMALLY
`GROWN SIDEWALL EMBODIMENTS DISCLOSE THE CLAIMED
`PROTRUDING GATE
`Petitioner demonstrated that Misra discloses the “protruding gate” limitation
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`because gate 28b protrudes above silicon nitride film 20. Petition, 40-42.
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`Petitioner additionally showed that Misra discloses the “protruding gate” limitation
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`“regardless of whether spacers 23 are constructed out of silicon nitride.” Petition,
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`42. As discussed in the sections that follow, PO fails to rebut Petitioner’s
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`additional showing for the embodiments where the spacers 23 are made of silicon
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`nitride. PO’s arguments also fail for the simple reason that they are based on the
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`incorrect premise that spacers 23 are necessarily made of silicon nitride – they are
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`not. PO offers no response for Misra’s embodiments where spacers 23 are made of
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`other materials such as silicon oxide. Ex. 1232, ¶9.
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`Misra expressly states that the spacers 23 may be replaced with other
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`materials formed through a thermal growth: “While nitride spacers formed by
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`deposition may be replaced or composited with a sidewall thermal growth, some
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`silicides do not oxidize effectively and may at least some deposition process to
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`obtain adequate source/drain to gate isolation.” Ex. 1204, 6:54-58 (emphasis
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`added). In other words, the spacers 23 are made of a thermally grown silicon
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`dioxide rather than silicon nitride. Ex. 1232, ¶10.
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`U.S. Patent 7,893,501
`IPR2017-01843
`Petitioner’s Reply to Patent Owner’s Response
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`Well aware of this disclosure, PO specifically questioned Dr. Shanfield on
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`this language during cross-examination. Ex. 2210, 262:6-24. In response to PO’s
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`questioning, Dr. Shanfield confirmed that the silicon nitride may be “replac[ed]
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`with sidewalk thermal growth.” Ex. 2210, 262:6-24. PO next asked whether this
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`disclosure in Misra was at least “describing that it is preferred to have some
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`deposition portion, at least some silicon nitride 23.” Dr. Shanfield confirmed that
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`it was not stating a preference for making spacers 23 out of silicon nitride: “No,
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`it’s explaining that you can form spacers, or you can replace the nitride spacers
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`with sidewall thermal growth, but this [some silicides not oxidizing effectively] is
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`something to watch out for.” Ex. 2210, 263:6-14. Ex. 1232, ¶11.
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`PO ignores this disclosure and testimony, offering no response for Misra’s
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`embodiments where the spacers 23 are made of other materials than silicon nitride.
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`Instead, PO’s arguments are each based on the incorrect premise that the spacers
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`23 are necessarily made of silicon nitride. The express disclosure of Misra and Dr.
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`Shanfield’s unrebutted testimony confirms the silicon nitride may be replaced with
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`other materials formed through thermal growth. Thus, Petitioner’s showing that
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`Misra discloses the “protruding gate” limitation stands unrebutted. Petition, 40-42.
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`Ex. 1232, ¶12.
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`U.S. Patent 7,893,501
`IPR2017-01843
`Petitioner’s Reply to Patent Owner’s Response
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`PO’s attempt to rebut Petitioner’s additional showing that Misra discloses
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`the “protruding gate” limitation even for embodiments where “spacers 23 are
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`constructed out of silicon nitride,” (Petition, 42) also fails for the reason discussed
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`below. Ex. 1232, ¶13.
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`III. PATENT OWNER’S CONSTRUCTION OF “SILICON NITRIDE
`FILM” APPLIES AN UNREASONABLE INTERPRETATION OF
`“LAYER”
`PO argues that Misra’s silicon nitride film 20 and its sidewall spacers 23 are
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`somehow multiple layers of a single film. This is the same argument PO advanced
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`in the POPR through an unduly narrow construction of the term “the gate electrode
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`protrudes upward from a surface level of parts of the silicon nitride film located at
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`both side surfaces of the gate electrode.” The POPR proposed the following
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`construction: “the gate electrode protrudes upward from a surface level of parts of
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`the silicon nitride film (which can be formed of one or more layers) located closest
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`to both side surfaces of the gate electrode.” POPR, 58. The Board properly
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`rejected this argument in the Institution Decision (“DI”), explaining: “Patent
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`Owner, however, mischaracterizes Petitioner’s argument. Nowhere does Petitioner
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`argue that the claims exclude a silicon nitride film having multiple layers.
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`Petitioner simply argues that a silicon nitride film need not include every silicon
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`nitride structure in a prior art device.” DI, 8; see also, id., 8-9 (“[W]e disagree that
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`U.S. Patent 7,893,501
`IPR2017-01843
`Petitioner’s Reply to Patent Owner’s Response
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`the claim requires that the silicon nitride film must encompass all silicon nitride
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`structures in a prior art device.”). Ex. 1232, ¶14.
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`Now in its Response, PO has merely restructured its prior construction and
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`still attempts to interpret the claim in the same way already rejected by the Board
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`(compare “the gate electrode protrudes upward from a surface level of parts of the
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`silicon nitride film located at both side surfaces of the gate electrode” as “the gate
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`electrode protrudes upward from a surface level of parts of the silicon nitride film
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`(which can be formed of one or more layers) located closest to both side surfaces
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`of the gate electrode,” POPR, 58, with “silicon nitride film” as “thin coating of one
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`or more layers of silicon nitride.” Response, 28.) Ex. 1232, ¶15.
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`PO then applies an unreasonable interpretation of “layer” to this construction
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`to repeat the same arguments that were rejected in the POPR. That is, PO argues
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`that two adjacent structures made of silicon nitride are somehow layers of the same
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`film, even when they are separate structures, formed through separate processes,
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`different functions. See e.g., Response, 31. Ex. 1232, ¶16.
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`In the case of Misra, even a cursory visual inspection of Fig. 5 shows that
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`silicon nitride film 20 and spacers 23 are two separate structures, not different
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`layers of a single film. Ex. 1232, ¶¶17-18.
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`U.S. Patent 7,893,501
`IPR2017-01843
`Petitioner’s Reply to Patent Owner’s Response
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`Moreover, no person of ordinary skill in the art would have considered silicon
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`nitride film 20 and spacers 23 to be two layers of a single film because they are
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`separate structures, they are formed through separate process steps, and they
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`perform different functions, as demonstrated in the Petition and discussed further
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`below. Petition, 42-43. Ex. 1232, ¶19.
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`The ’501 patent simply states that “each of the internal stress films 8a and
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`8b does not have to be a single layer but may include multiple layers, as long as
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`each of the internal stress films 8a and 8b can apply a stress to the substrate as a
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`whole.” Ex. 1201, 5:60-63 (emphasis added). This description merely recognizes
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`that a film can have multiple layers deposited on top of each other. Nowhere does
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`the ’501 patent state that two adjacent films would be considered “layers” of a
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`single film, much less than any two adjacent structures made of the same material
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`U.S. Patent 7,893,501
`IPR2017-01843
`Petitioner’s Reply to Patent Owner’s Response
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`are somehow “layers” of a single film. Such an interpretation is plainly not the
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`reasonable. The ’501 patent itself merely recognizes that the film 8a could be
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`deposited with a single layer or it could be deposited in multiple layers (and the
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`same for goes for the separate, adjacent film 8b). This does not mean that other,
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`partially adjacent, or even fully adjacent, structures necessarily become part of the
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`same film simply as a result of being adjacent.4 Ex. 1232, ¶20.
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`Finally, as discussed in more detail below, PO also repeats its rejected
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`argument that the silicon nitride film must be “located closest to both side surfaces
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`of the gate electrode,” this time without expressly including this requirement in its
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`claim construction. See e.g., Response, 11, 20, 58. This argument again fails. Ex.
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`1232, ¶21.
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`IV. NO POSITA WOULD HAVE THOUGHT THE LAYER 20 AND THE
`SPACER 23 WERE THE SAME FILM
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`4 Patent Owner’s Responses in this proceeding and in related IPR2017-01841 make
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`clear its constructions are driven by attempting to avoid the prior art because PO
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`offers constructions for different terms in each Response, despite those Responses
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`both addressing the same challenged patent and claims. Compare IPR2017-01843
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`(construing only the term “silicon nitride film”) with IPR2017-01841 Response
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`(construing only the term “active region made of a semiconductor substrate”).
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`U.S. Patent 7,893,501
`IPR2017-01843
`Petitioner’s Reply to Patent Owner’s Response
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`A.
`The Petition’s Showing is Confirmed by the Prosecution History
`PO argues that the Petition’s interpretation of Misra is inconsistent with the
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`prosecution history, in that the claims “would not distinguish over Xiang or
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`Matsuda, and would read on those references in the same manner the Petitions seek
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`to read the claims onto Misra.” Response, 63-66. PO is wrong. Ex. 1232, ¶22.
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`In Xiang, both “etch stop layers” 80 and 82 (208 and 210 in Fig. 10) perform
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`the same function (“etch stop”) and are deposited in the same manufacturing step.
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`Ex. 2202, 4:9-14, 6:35-36 (“As illustrated in FIG. 10, etch stop layers 208 and 210
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`are deposited in step 212.”) Likewise, in Matsuda, “protective insulating film 9a”
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`is deposited together with “sidewall insulating film 10” and “underlying insulting
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`film 8” during a single manufacturing step, forming “sidewalls 11.” Ex. 2203,
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`8:11-14 (“[I]n a process step shown in FIG. 3B, the sidewall insulating film 10, the
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`protective insulating film 9 and the underlying insulating film 8 are etched in this
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`order by anisotropic dry etching, thereby forming sidewalls 11 each having a
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`multilayer structure including an underlying insulating film 8 a, a protective
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`insulating film 9 a and a sidewall insulating film 10 a.”) Accordingly, in both
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`Xiang and Matsuda, the layers cited during prosecution are each: deposited in a
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`single step; perform a single function; and comprise a singular structure. Ex. 1232,
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`¶23.
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`U.S. Patent 7,893,501
`IPR2017-01843
`Petitioner’s Reply to Patent Owner’s Response
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`In contrast, Misra’s layer 20 and spacer 23 are formed through different
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`process steps, serve different functions, and are part of separate structures. As
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`Misra describes for layer 20: “FIG. 2 illustrates that a thin plasma-enhanced nitride
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`(PEN or like material) layer 20 is deposited overlying the trench isolation regions
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`14 and the silicide layer 18. Preferably, the plasma enhanced nitride layer is
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`deposited to a thickness of roughly 500 angstroms. Plasma enhanced nitride layer
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`20 is provided for use as an etch stop layer when subsequently forming contact
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`openings to source and drain electrodes of the MOS transistors.” Ex. 1204, 5:20-
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`27 (emphasis added). Ex. 1232, ¶24.
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`Misra then describes a separate process to form spacer 23: “After formation
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`of the sacrificial oxide 25, silicon nitride is deposited and reactive ion etched to
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`form silicon nitride spacers 23 on top of the sacrificial oxide 25. The etch used to
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`form silicon nitride spacers 23 is selective to the sacrificial oxide 25…. Notice that
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`the spacers 23 provides a necessary offset not only to compensate for lateral
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`diffusion of the source and drain regions 26 and 28, but to electrically isolate
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`subsequent gate electrode formations from the silicide regions 18 whereby Miller
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`effects may be reduced.” Ex. 1204, 6:37-54. Ex. 1232, ¶25.
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`As shown in the figures below, the steps to form silicon nitride film 20 in
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`Fig. 2 and spacers 23 in Fig. 5 are not only separate steps that form completely
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`U.S. Patent 7,893,501
`IPR2017-01843
`Petitioner’s Reply to Patent Owner’s Response
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`different structures, they are also separated by multiple intervening steps shown in
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`Figs. 3-4.
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`Ex. 1204, Figs. 2-5. Ex. 1232, ¶26.
`In fact, Dr. Glew confirmed this understanding during his deposition,
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`agreeing that Misra describes forming silicon nitride layer 20 during the process
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`shown in Figure 2 (above), and that Figures 3 and 4 show intervening process steps
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`that occur before the spacers 23 are formed in Figure 5. Ex. 1231, 130:11-19 (“Q.
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`U.S. Patent 7,893,501
`IPR2017-01843
`Petitioner’s Reply to Patent Owner’s Response
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`In Figure 2, the silicon nitride film 20 has already been deposited, right? A. Layer
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`20 is shown being deposited in Figure 2.”), 130:20-25 (“Q. In Figure 2, spacers
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`23 have not yet been formed, correct? A. Column 6, Lines 34 through 56 describe
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`that spacers 23 are formed in Figure 5, and that's where it's shown, and it's not
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`yet present.”), 131:6-12 (“Q. Figures 3 and 4 show additional intermediate stages
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`in the manufacturing process in between the steps shown in Figure 2 and what's
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`depicted in Figure 5, correct? A. Yes, Figure 3 are intermediate in between
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`Figures 2 and 5 in the manufacturing process.”) (emphasis added). Ex. 1232,
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`¶27.
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`The disclosure in Misra for the silicon nitride layer 20 and the spacers 23 is
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`just like the description in the ’501 patent, where the silicon nitride film 8a and the
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`spacers 7 are formed through separate steps shown in Figs. 2A-2C.
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`U.S. Patent 7,893,501
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`Petitioner’s Reply to Patent Owner’s Response
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`Ex. 1201, Figs. 2A-2C. Ex. 1232, ¶28.
`By contrast, in Xiang and Matsuda, the film is deposited in a single step. As
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`shown below, “etch stop layers” 208 and 210 in Xiang are formed during a single
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`manufacturing step (namely, step 212, “Deposit Etch Stop Layer”).
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`U.S. Patent 7,893,501
`IPR2017-01843
`Petitioner’s Reply to Patent Owner’s Response
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`Dr. Shanfield confirms—consistent with the disclosure in Xiang—that a POSITA
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`would have understood that etch stop layer 208 on the left side of the gate and etch
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`stop layer 210 on the right side of the gate are formed by depositing a single silicon
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`nitride film on each side of the gate and that the activities associated with this
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`deposition process would be considered a single manufacturing step. Ex. 2202,
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`4:9-14, 6:35-36 (“As illustrated in FIG. 10, etch stop layers 208 and 210 are
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`deposited in step 212.”), Figs. 2, 9, 10. Ex. 1232, ¶29.
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`Likewise, in Matsuda, “protective insulating film 9a” is deposited together
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`with “sidewall insulating film 10” and “underlying insulting film 8” during a single
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`manufacturing step to form “sidewalls 11.” Ex. 2203, 8:11-14. Ex. 1232, ¶30.
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`U.S. Patent 7,893,501
`IPR2017-01843
`Petitioner’s Reply to Patent Owner’s Response
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`Additionally, and contrary to Dr. Glew’s assertions (Ex. 2208, ¶¶146-147), a
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`POSITA would have understood that the references to “etch stop layers 80 and 82”
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`in Xiang’s Fig. 1 refer to the etch stop layer 80 on the left side of the gate and etch
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`stop layer 82 on the right side of the gate, not to vertical and horizontal portions of
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`each etch stop layer. This is confirmed by the consistent usage of pairs of
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`identifiers for the left and right structures (e.g., left spacer 70 and right spacer 72,
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`left filler layer 84 and right filler layer 86, left silicide region 26 and right silicide
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`region 28, etc.). Dr. Glew’s testimony is also contrary to Figs. 10-12 in Xiang,
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`where the labels 208 and 210 both point to the same respective portions of the left
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`and right etch stops, confirming that the numerals identify a left etch stop and a
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`right etch stop, not upper and lower portions of each etch stop. This is also
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`confirmed by the shading in the figures in Xiang, where etch stop layer 80 and etch
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`stop layer 82 (as well as etch stop layers 208 and 210) are each shaded in a single
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`pattern of vertical lines. There is no distinction or separation within either etch
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`Petitioner’s Reply to Patent Owner’s Response
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`stop layer 80 or etch stop layer 82 to suggest that either etch stop somehow
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`comprises multiple separate structures. Likewise, in Matsuda, layer 9a is shaded in
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`a consistent pattern of diagonal lines, with no distinction or separation made to
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`denote two separate structures. Ex. 1232, ¶¶31-32.
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`Accordingly, simply positioning Misra’s silicon nitride film 20 and spacer
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`23 next to each other cannot make them a single structure when they have each
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`been formed using a different technique and will undisputedly have significant
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`differences in their individual properties and functions. Ex. 1232, ¶33.
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`B.
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`Patent Owner Cannot Overcome the Overwhelming Evidence of
`Invalidity with its Unreasonable Interpretation of “Silicon Nitride
`Film”
`As described above, PO again argues that the plasma enhanced layer 20 and
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`silicon nitride spacers 23 of Misra are both part of a single “silicon nitride film”
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`because a film can have multiple layers under its proposed interpretation. As noted
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`previously, ’501 patent merely recognizes that a film may have multiple layers in
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`the context of a film formed by stacking additional layers on top of previous
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`layers: “Furthermore, each of the internal stress films 8a and 8b does not have to
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`be a single layer but may include multiple layers, as long as each of the internal
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`stress films 8a and 8b can apply a stress to the substrate as a whole.” Ex. 1201,
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`U.S. Patent 7,893,501
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`5:60-63. The ’501 patent provides no support for the notion that two adjacent
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`structures would be considered multiple layers of a single film. Ex. 1232, ¶34.
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`Dr. Glew’s own testimony confirms that the term “layer” simply refers to
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`different layers of a film formed on top of each other. E.g., Ex. 2208, ¶71 (“It is
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`somewhat akin to spray painting where each spray of paint (even if from the same
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`spray paint can) is a different process that produces a layer.”). That is, a film can
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`be applied in a single layer or multiple layers, but that does not mean that adjacent
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`structures are somehow part of the same film. Ex. 1232, ¶35.
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`The processes of applying multiple layers of paint on top of each other or
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`depositing a film in a semiconductor device with multiple layers stacked on top of
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`each other is completely distinct from Misra. As described above, layer 20 and
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`spacer 23 are two different structures, formed through different process steps, and
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`performing different functions. That they happened to be adjacent does not make
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`them into a single film. Ex. 1232, ¶36.
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`There is a distinction between multiple stacked layers (as contemplated and
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`described by the ’501 patent and confirmed by Dr. Glew) and multiple separate
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`structures that are adjacent to each other. For example, looking at the diagram of
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`stacked layers provided in the Response (Response, 33), the stress field adds and
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`compressive stress is approximately double on the bottom. As the ’501 patent
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`U.S. Patent 7,893,501
`IPR2017-01843
`Petitioner’s Reply to Patent Owner’s Response
`
`
`describes, “Furthermore, each of the internal stress films 8a and 8b does not have
`
`to be a single layer but may include multiple layers, as long as each of the internal
`
`stress films 8a and 8b can apply a stress to the substrate as a whole.” Ex. 1201,
`
`5:60-63. That is, the film applies a stress based on the sum of the stresses of the
`
`stacked layers. By contrast, for separate structures that are adjacent to each other,
`
`the tensile stress profile of each structure dips on the edge of each structure
`
`because there is nothing for it to act on. Ex. 1232, ¶37.
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`To illustrate this distinction, as would be understood by a POSITA, Dr.
`
`Shanfield has provided the following diagrams. First, Dr. Shanfield illustrates a
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`single thin film (in gray) with intrinsic tensile stress that is deposited on a silicon
`
`substrate (blue). This single thin film applies a compressive stress (indicated by
`
`the arrows) downward into the substrate. The compressive stress has a magnitude
`
`and depth as shown by the compressive stress field profile (peach). The region of
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`maximum substrate stress is measured at the approximate center of the substrate in
`
`this arrangement, where the compressive stress profile (peach) is at its maximum
`
`depth. The stress level induced in the underlying substrate drops to approximately
`
`zero at each edge of the thin film. Ex. 1232, ¶38.
`
`- 21 -
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`U.S. Patent 7,893,501
`IPR2017-01843
`Petitioner’s Reply to Patent Owner’s Response
`
`
`
`
`Single thin film applying compressive stress into substrate
`
`
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`Next, Dr. Shanfield illustrates two films (one gray, one yellow), stacked one
`
`on top of the other as multiple layers that can apply a stress to the substrate (blue)
`
`as a whole, as is consistent with the disclosure of the ’501 patent (Ex. 1201, 5:60-
`
`63: “Furthermore, each of the internal stress films 8a and 8b does not have to be a
`
`single layer but may include multiple layers, as long as each of the internal stress
`
`films 8a and 8b can apply a stress to the substrate as a whole.”) In this example,
`
`the two films apply a compressive stress field that is the sum of the two stacked
`
`layers, resulting in a greater compressive stress field (orange) in the substrate –
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`approximately twice the magnitude of compressive stress as in the first example.
`
`Once again, the region of maximum substrate stress is measured at the approximate
`
`center of the substrate in this arrangement, where the compressive stress profile
`
`(orange) is at its maximum depth. The stress level induced in the underlying
`
`substrate drops to approximately zero at each edge of the thin film. Ex. 1232, ¶39.
`- 22 -
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`
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`U.S. Patent 7,893,501
`IPR2017-01843
`Petitioner’s Reply to Patent Owner’s Response
`
`
`
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`Multiple stacked film layers applying compressive stress into substrate
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`
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`Finally, Dr. Shanfield illustrates two films (gray and yellow) deposited side-
`
`by-side onto the substrate (blue). In this example, and in contrast with the stacked
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`arrangement shown above, each film applies its own compressive stress into the
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`substrate, resulting in two independent compressive stress fields (peach). Here,
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`there is a region of near zero compressive stress at the boundary between the two
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`side-by-side films, as identified by the large arrow. In other words, placing two
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`separately deposited (and, in this case, identical) thin films side-by-side does not
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`provide a higher magnitude stress field and, in contrast, results in each film
`
`generating its own separate stress film, with the condition of zero stress in the
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`underlying substrate at the point between the two separate films. Ex. 1232, ¶40.
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`- 23 -
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`
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`U.S. Patent 7,893,501
`IPR2017-01843
`Petitioner’s Reply to Patent Owner’s Response
`
`
`
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`Two films deposited side-by-side, each applying its own compressive stress
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`Dr. Glew provides similar examples of stacked layers and side-by-side films
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`deposited on substrates in his declaration, but omits the stress fields illustrating
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`how two side-by-side films differ from a single film (whether formed with a single
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`layer or multiple stacked layers). Ex. 2208, ¶70, Figure 1. Dr. Shanfield has
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`provided annotations of those examples in the same way as above to illustrate: (i)
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`the single added compressive stress field (orange) of the stacked layers (purple);
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`and (ii) the two separate compressive stress fields (peach) of each of the separate
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`side-by-side films (green). Ex. 1232, ¶41.
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`Figure 1 of Dr. Glew’s declaration (Ex. 2208) annotated by Dr. Shanfield
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`
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`(Ex. 1232, ¶41)
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`- 24 -
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`U.S. Patent 7,893,501
`IPR2017-01843
`Petitioner’s Reply to Patent Owner’s Response
`
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`Accordingly, each structure applies different stresses because they are
`
`separate structures and there is a discontinuity in the stress profile at the boundary
`
`between the two structures, even when they are adjacent. In fact, that “non-
`
`uniform stresses exist near the edges of thin films as a result of satisfying the
`
`boundary conditions” has been a well-known mechanical property of thin films for
`
`decades. Ex. 1233, Abstract. Ex. 1232, ¶42.
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`As Dr. Shanfield explains, because layer 20 and spacer 23 are separate
`
`structures, there will be a discontinuity at the boundary of 20 and 23 not present in
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`Xiang or Matsuda. Thus, a silicon nitride film can have one or more layers applied
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`on top of each other, but two wholly different structures—namely, a silicon nitride
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`film and a sidewall structure—cannot be considered layers of the same film, even
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`if the edge of the silicon nitride film is adjacent to the sidewall. Ex. 1232, ¶43.
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`
`
`V. MISRA’S GATE PROTRUDES ABOVE THE PARTS OF THE
`SILICON NITRIDE FILM
`PO’s argument that “Misra fails to satisfy the challenged claims even if
`
`silicon nitride layers 20, 23 are considered to be separate films” still implicitly
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`requires that the plasma enhanced layer 20 and silicon nitride spacers 23 both be
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`part of the “silicon nitride film” in order for the silicon nitride spacers 23 to be the
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`closest part of the film, rather than a separate structure. Response, 71-76. Thus,
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`this argument fails for the reasons above. Ex. 1232, ¶44.
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`- 25 -
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`U.S. Patent 7,893,501
`IPR2017-01843
`Petitioner’s Reply to Patent Owner’s Response
`
`
`Additionally, neither the plain language of the claims, the specification, nor
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`the file history, prohibit there being a silicon nitride spacer between the gate
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`electrode and the silicon nitride film. The claim language simply requires that “the
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`gate electrode protrudes upward from a surface level of parts of the silicon nitride
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`film located at both side surfaces of the gate electrode.” The claims in fact
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`expressly recognize that the silicon nitride film “located at both side surfaces of the
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`gate electrode” need not be located closest to the side surfaces of the gate, but
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`instead may be separated from the side surfaces of the gate by spacers. For
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`example, claim 7, which depends from claim 1, recites that “the silicon nitride film
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`is formed over the side surfaces of the gate electrode with the sidewall interpos
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