UNITED STATES PATENT AND TRADEMARK OFFICE
`___________________
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`___________________
`
`INTEL CORPORATION,
`Petitioner,
`
`v.
`
`DSS Technology Management, Inc.,
`Patent Owner
`___________________
`
`Case No. IPR2016-00288
`U.S. Patent 6,784,552
`___________________
`
`
`PATENT OWNER PRELIMINARY RESPONSE TO PETITION
`PURSUANT TO 37 C.F.R. § 42.107
`
`
`
`
`
`
`
`
`
`

`
`IPR2016-00288
`Patent 6,784,552
`
`TABLE OF CONTENTS
`
`Page
`TABLE OF AUTHORITIES ................................................................................... iii
`
`I. 
`
`II. 
`
`III. 
`
`IV. 
`
`V. 
`
`INTRODUCTION .............................................................................................................. 2 
`A. 
`Grounds in Petition ................................................................................................. 3 
`
`THE ‘552 PATENT ............................................................................................................ 3 
`A. 
`Overview ................................................................................................................. 3 
`B. 
`Prosecution History Summary ................................................................................ 9 
`
`PETITION PROCEDURAL DEFICIENCIES ................................................................. 10 
`
`CLAIM CONSTRUCTION AND ORDINARY SKILL IN THE ART ........................... 14 
`A. 
`Person Having Ordinary Skill In The Art ............................................................. 14 
`B. 
`Claim Construction ............................................................................................... 15 
`“a side of the electrically insulative spacer has an angle relative to
`1. 
`the substrate surface that is either a right angle or an acute angle of
`more than 85°” .......................................................................................... 15 
`
`THE CHALLENGED CLAIMS ARE PATENTABLE OVER HEATH ......................... 19 
`A. 
`Summary of Heath ................................................................................................ 20 
`B. 
`Heath Does Not Anticipate Independent Claim 8 ................................................. 24 
`Anticipation By Heath Premised On Petitioner’s Construction
`1. 
`Must Be Denied ........................................................................................ 24 
`Heath Does Not Disclose Using A Low Selectivity Etch To Avoid
`The Sloped Spacer Problems Of The Prior Art ........................................ 26 
`Obviousness Grounds Based On Heath Must Be Denied ..................................... 30 
`
`C. 
`
`2. 
`
`VI. 
`
`THE CHALLENGED CLAIMS ARE PATENTABLE OVER HEATH IN VIEW
`OF DENNISON ................................................................................................................ 30 
`
`VII.  CONCLUSION ................................................................................................................. 35 
`
`
`i
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`

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`IPR2016-00288
`Patent 6,784,552
`
`TABLE OF AUTHORITIES
`
`Page(s)
`
`
`CASES
`Cisco Systems, Inc. v. AIP Acquisition, LLC, Case No. IPR2014-00247 ................ 13
`Enzo Biochem, Inc. v. Applera Corp., 599 F.3d 1325 (Fed. Cir. 2010) .................. 24
`Kinetic Techs., Inc. v. Skywork Solutions, Inc., Case No. IPR2014-00530 ............. 11
`Kinetic Techs., Inc. v. Skywork Solutions, Inc., Case No. IPR2014-00529 ....... 11, 12
`LG Display, Ltd. v. Innovative Display Technologies LLC, Case No.
`IPR2014-01094 ............................................................................................. 10, 12
`Microsoft Corp. v. Proxyconn, Inc., Case No. IPR2012-00026 .............................. 24
`Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (en banc) ............. 13, 18, 24
`In re Rambus, Inc., 694 F.3d 42 (Fed. Cir. 2012) .................................................... 13
`Wowza Media Sys, LLC and Coffee Cup Partners, Inc. v. Adobe Sys. Inc.,
`Case No. IPR2013-00054 ................................................................................... 11
`ZTE Corporation v. ContenGuard Holdings, Inc., Case No. IPR2013-00139 ....... 24
`STATUTES
`35 U.S.C. § 312 ............................................................................................. 9, 13, 14
`35 U.S.C. § 313 .......................................................................................................... 1
`OTHER AUTHORITIES
`37 C.F.R. § 42.22 ................................................................................................. 9, 13
`37 C.F.R. § 42.104 ............................................................................................... 9, 14
`37 C.F.R. § 42.107 ..................................................................................................... 1
`77 Fed. Reg. 48,756 (proposed Aug. 14, 2012) ....................................................... 10
`
`
`
`1
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`

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`IPR2016-00288
`Patent 6,784,552
`
`PATENT OWNER PRELIMINARY RESPONSE
`UNDER 37 C.F.R. § 42.107
`Pursuant to 37 C.F.R. § 42.107, DSS Technology Management, Inc.,
`
`(“Patent Owner”) hereby submits the following Preliminary Response to the
`
`Petition (Paper 2) seeking inter partes review of U.S. Patent No. 6,784,552 (the
`
`“’552 Patent”) filed by Intel Corporation (“Petitioner”). This filing is timely under
`
`35 U.S.C. § 313 and 37 C.F.R. § 42.107, as it is filed within three months of the
`
`mailing date of the Notice of Filing Date Accorded to Petition and Time for Filing
`
`Patent Owner Preliminary Response (Paper 4), mailed December 14, 2015.
`
`I.
`
`INTRODUCTION
`The Patent Trial and Appeal Board (the “Board”) should deny the Petition’s
`
`request to institute an inter partes review of U.S. Patent No. 6,784,552 (the “‘552
`
`Patent”) because the grounds in the petition do not demonstrate a reasonable
`
`likelihood that the Petitioner would prevail with respect to any of the claims
`
`challenged in the Petition. None of the prior art cited in this Petition suggests the
`
`solution to lateral spacer erosion invented and claimed by the inventors of the ‘552
`
`patent. Petitioner attempts to rely upon simplified and misleading figures in the
`
`cited references which are at best, merely cumulative of the prior-art figures
`
`included in the Background of the Invention portion of the ‘552 patent
`
`specification.
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`2
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`IPR2016-00288
`Patent 6,784,552
`
`In consideration of the evidence and arguments below, Patent Owner
`
`submits that Petitioner has failed to demonstrate a reasonable likelihood of success
`
`with respect to any of the challenged claims. A trial should not be instituted.
`
`Patent Owner has limited its identification of deficiencies in Petitioner’s argument
`
`in this Preliminary Response, but does not waive any additional arguments by not
`
`addressing them herein.
`
`A. Grounds in Petition
`Petitioner challenges claims 8-12 of the ‘552 Patent on the following
`
`grounds:
`
`1.
`
`Claims 8-12 and 4-7 are allegedly anticipated by U.S. Patent No.
`
`4,686,000 (“Heath”) (Ex. 1103);
`
`2.
`
`Claims 8-12 are allegedly obvious over Heath in view of U.S. Patent
`
`No. 5,338,700 (“Dennison”) (Ex. 1104).
`
`II. THE ‘552 PATENT
`A. Overview
`The ‘552 Patent, entitled “Structure Having Reduced Lateral Spacer
`
`Erosion” issued to James E. Nulty et al. on August 31, 2004. The ‘552 Patent
`
`issued from U.S. App. No. 09/540,610 (“the ‘610 Application”), which was filed
`
`on March 31, 2000, and was a division of application No. 08/577,751, filed on
`
`December 22, 1995, which is now U.S. Patent No. 6,066,555 (the “’555 patent”).
`
`3
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`IPR2016-00288
`Patent 6,784,552
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`The ‘552 Patent is generally directed to improved methods for etching
`
`openings in insulating layers and a semiconductor device with well-defined contact
`
`openings. Ex. 1101 at 1:9-12. In the past, the practice with respect to forming
`
`contact openings during the fabrication of semiconductor devices, particularly self-
`
`aligned contact openings, was to use etchants with high selectivity to protect
`
`underlying regions. Id. at 4:61-5:17. However, the properties of a highly selective
`
`etch of the overlying etch layer can transform a substantially rectangular spacer
`
`adjacent to the contact region into a sloped spacer. Id. Before the conductor
`
`materials are added to the contact opening, the opening was cleaned with a sputter
`
`etchant which can erode a portion of the sloped insulating spacer. Id. at 5:35-41.
`
`Thus in conventional self-aligned contact structures, the diagonal thickness of the
`
`spacer, rather than the vertical thickness of the insulating layer, determined the
`
`minimum insulating layer thickness for the gate. Id. at 6:8-12. Sloping spacers
`
`limit the number of structures that can be included on a device. The present
`
`invention avoids this problem by retaining the substantially rectangular profile of
`
`the insulating spacers.
`
`An embodiment of the ‘552 Patent is captured in Figure 4(L), which shows a
`
`cross-sectional planar side view of the inventive structure:
`
`4
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`IPR2016-00288
`Patent 6,784,552
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`
`
`Figure 4(L) depicts conductive contacts (480) deposited into contact
`
`openings on top of diffusion regions (405). A conductive layer (415), such as a
`
`gate, is separated from the conductive contact by an insulating spacer (420) and an
`
`etch stop material (440). The substantially rectangular insulating spacer (420 and
`
`435) is expressly shown in Figure 4(D):
`
`
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`5
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`Patent 6,784,552
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`The etch stop material that remains adjacent to the insulating spacer serves
`
`as additional spacer material to insulate the gate from the conductive contact. Ex.
`
`1101 at 12:61-65, and 13:63-65. Figure 4(K) depicts a close-up view of the cross-
`
`sectional portion of the contact opening (460).
`
`
`The etchant utilized to remove the silicon nitride etch stop material (440)
`
`from the contact opening (460) has a low selectivity for etching the silicon nitride
`
`etch stop material compared to the underlying insulation layer (420). Ex. 1101 at
`
`12:66-13:2. The low selectivity etch yields an insulating layer spacer portion
`
`(435) that retains a rectangular or “boxy” profile. Id. at 13:4-6.
`
`The ‘552 Patent is aimed at providing a process for minimizing lateral
`
`spacer erosion of an insulating layer on an enclosed contact region, and a device
`
`including a contact opening with a small alignment tolerance relative to a gate
`
`6
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`Patent 6,784,552
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`electrode or other structure. The features of the ‘552 Patent are captured by the
`
`challenged claims. For example, independent claim 8 recites:
`
`8. A structure, comprising:
`
`(a) a first electrically conductive material formed in and/or on a surface
`
`of a substrate;
`
`(b) a contact opening in a region adjacent to a second electrically
`
`conductive material formed on the substrate;
`
`(c) an electrically insulative spacer in the contact opening adjacent
`
`to the second electrically conductive material;
`
`(d) an etch stop material over the electrically insulative spacer and
`
`the first and second electrically conductive materials, the
`
`etch stop material being a different material from the insulative
`
`spacer;
`
`(e) a blanket layer over the etch stop material; and
`
`(f) an opening through a first part of the etch stop material to
`
`the first electrically conductive material,
`
`wherein a side of the electrically insulative spacer has an
`
`angle relative to the substrate surface that is either a right
`
`angle or an acute angle of more than 85°.
`
`7
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`Patent 6,784,552
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`The claimed structure requires that a side of the electrically insulative spacer
`
`has an angle relative to the substrate surface of more than 85° in order for the
`
`shape to be “substantially rectangular.” Ex. 1101 at 8:41-43. A person of ordinary
`
`skill in the art would understand that to retain the substantially rectangular profile
`
`of the insulating spacer, the etching conditions utilized for the etch-stop etch must
`
`have a low selectivity for etching the etch-stop layer compared to the underlying
`
`insulating material. See id. at 7:58-60.
`
`As described in the background of the invention, one of skill in the art would
`
`understand that the current practice at the time of the invention was to utilize a
`
`high selectivity etch to remove the etch-stop layer, which will transform a
`
`substantially rectangular insulating spacer into a sloped spacer. See id. at 4:61-
`
`5:17. This sloped spacer can be subsequently eroded in the lateral direction in later
`
`processing steps thereby potentially causing an unwanted electrical short circuit.
`
`Id. at 6:13-21. This lateral erosion and potential electrical short circuit are the
`
`problems solved by the ‘552 Patent.
`
`Challenged claims 9-12 depend from claim 8 and include various additional
`
`limitations. For example, challenged claim 9 requires that the electrically
`
`insulative spacer has a surface portion without overlying etch stop material. Id. at
`
`claim 9. Challenged claim 10 requires that the insulating spacer surface portion
`
`8
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`

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`IPR2016-00288
`Patent 6,784,552
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`without overlying etch stop material comprises a surface portion most distant from
`
`said substrate. Id. at claim 10.
`
`B.
`Prosecution History Summary
`The ‘552 patent was filed on March 31, 2000. The ‘552 patent is a
`
`divisional of, and claims priority to, U.S. Patent No. 6,066,555 (the “’555 patent”),
`
`which was filed on December 22, 1995.
`
`The original claims of the ‘552 patent were directed to forming a transistor
`
`structure with a “substantially rectangular” spacer portion adjacent to a contact
`
`opening. Ex. 1109 at 28-32. During the course of the prosecution of the
`
`application, the applicants amended the specification to define “substantially
`
`rectangular” as follows: “The phrase ‘substantially rectangular’ means that a side
`
`of the spacer has an angle relative to the substrate surface of more than 85°.” Ex.
`
`1119 at 2, 6. The applicants also amended the independent claims again to require
`
`“wherein a side of the insulating spacer has an angle relative to the substrate
`
`surface that is either a right angle or an acute angle of more than 85°.” Id. at 3-4.
`
`Following this amendment, the Examiner allowed the claims. Ex. 1120. During
`
`the amendment and response to the office action, the applicants explained that the
`
`prior art methods of transistor fabrication “use[d] etchants with high selectivity”
`
`that could “transform a substantially rectangular spacer adjacent to the contact
`
`region into a sloped spacer.” Ex. 1118 at 4 (emphasis added).
`
`9
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`Patent 6,784,552
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`III. PETITION PROCEDURAL DEFICIENCIES
`The Board may initially dispose of the Petition on procedural grounds for
`
`failure to comply with statutory requirements. If the Board is unwilling to deny the
`
`Petition outright, then it should give no weight to the unsupported and conclusory
`
`arguments that make up the entirety of the Petition and the accompanying
`
`Declaration of Dr. Bravman (Ex. 1102, Paper 8).
`
`A petition for inter partes review must “identif[y], in writing and with
`
`particularity, each claim challenged, the grounds on which the challenge to each
`
`claim is based, and the evidence that supports the grounds for the challenge to each
`
`claim.” 35 U.S.C. § 312(a)(3). According to 37 C.F.R. § 42.104(b)(4), a petition
`
`for inter partes review must identify “[h]ow the construed claim is unpatentable
`
`under the statutory grounds” on which the petitioner challenges the claims, and
`
`“must specify where each element of the claim is found in the prior art patents or
`
`printed publications relied upon.” Section 42.104(b)(5) of the Code of Federal
`
`Regulations adds that the Petition must “identify[] specific portions of the evidence
`
`that support the challenge.” Similarly, 37 C.F.R. § 42.22(a)(2) states that each
`
`petition must include “[a] full statement of the reasons for the relief requested,
`
`including a detailed explanation of the significance of the evidence including
`
`material facts, and the governing law, rules, and precedent.” The Office Patent
`
`Trial Practice Guide suggests that parties requesting inter partes review should
`
`10
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`

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`IPR2016-00288
`Patent 6,784,552
`
`“avoid submitting a repository of all the information that a judge could possibly
`
`consider, and instead focus on concise, well-organized, easy-to-follow arguments
`
`supported by readily identifiable evidence of record.” 77 Fed. Reg. 48,756, 48,763
`
`(proposed Aug. 14, 2012) (to be codified at 37 C.F.R. pt. 42). The Board is
`
`empowered to exclude or give no weight to the evidence where a party has failed
`
`to state its relevance or to identify specific portions of the evidence that support the
`
`challenge. LG Display, Ltd. v. Innovative Display Technologies LLC, Case No.
`
`IPR2014-01094, Paper 10 at 9 (PTAB, Jan. 13, 2015) and Paper 18 at 3-4 (April 9,
`
`2015).
`
`Here, the Petition is virtually devoid of analysis and consists almost entirely
`
`of claim charts with misleading figures from the cited references along with
`
`conclusory parentheticals generally equating the claim elements to those figures.
`
`This is all done under the imprimatur of the Petitioner’s declarant, Dr. Bravman. A
`
`review of Dr. Bravman’s Declaration, however, reveals that it is merely a recitation
`
`of the Petition’s information with no further analysis and certainly no detailed
`
`explanation of the significance of the quotations and citations from the applied
`
`references. Id., Paper 18 at 4 (denying institution and according the petition and
`
`supporting declaration minimal weight for failing to discuss the relevance of the
`
`evidence to the challenge raised or include a detailed explanation of the
`
`significance of the quotations and citations from the applied references). See also
`
`11
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`IPR2016-00288
`Patent 6,784,552
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`Kinetic Techs., Inc. v. Skywork Solutions, Inc., Case No. IPR2014-00529, Paper 8,
`
`at 15 (PTAB, Sept. 23, 2014) (“Merely repeating an argument from the Petition in
`
`the declaration of a proposed expert does not give that argument enhanced
`
`probative value.”); Kinetic Techs., Inc. v. Skywork Solutions, Inc., Case No.
`
`IPR2014-00530, Paper 8 (PTAB, Sept. 29, 2014) (affording little to no weight to a
`
`declaration that is merely a copy of the petition); Wowza Media Sys, LLC and
`
`Coffee Cup Partners, Inc. v. Adobe Sys. Inc., Case No. IPR2013-00054, Paper 12,
`
`at 12 (PTAB, Apr. 8, 2013) (finding a declaration that simply tracks and repeats
`
`the Petition unhelpful).
`
`For example, large portions of Dr. Bravman’s Declaration appear to be exact
`
`copies of the arguments in the Petition that have been wholesale cut-and-pasted
`
`from the Petition. For example, see the following images, infra:
`
`
`
`12
`
`

`
`To illustrate yet another example of the ubiquitous similarities between the
`
`Petition and the Declaration, please see the following set of images:
`
`IPR2016-00288
`Patent 6,784,552
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`
`
`A comparison of the Petition with Exhibit 1102, such as the one above,
`
`reveals that the expert analysis is nearly indistinguishable from the Petitioner’s
`
`claim charts that attempt to read the cited references upon the claimed inventions.
`
`See e.g., Kinetic Techs., IPR2014-00529, Paper 8 at 15 (“Merely repeating an
`
`argument from the Petition in the declaration of a proposed expert does not give
`
`that argument enhanced probative value.”) In addition, Dr. Bravman fails to
`
`explain the significance regarding the meaning of the disputed claim terms as
`
`understood by one skilled in the art. See Ex. 1102 at 31-37. Further, as in LG
`
`Display, Ltd., the Board should give minimal weight to Petitioner’s cited evidence,
`
`as previously discussed.
`
`13
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`Patent 6,784,552
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`Because the Petition fails to meet the threshold standards as required under
`
`35 U.S.C. § 312(a)(3), 37 C.F.R. § 42.22(a)(2), and 37 C.F.R. § 42.104(b)(4)–(5),
`
`the Board should determine that the information presented in the Petition cannot
`
`demonstrate a reasonable likelihood that any of the challenged claims are
`
`unpatentable based on the asserted grounds.
`
`IV. CLAIM CONSTRUCTION AND ORDINARY SKILL IN THE ART
`Claims of an expired patent, as is the present case, are construed in a manner
`
`similar to that of a district court’s review. In re Rambus, Inc., 694 F.3d 42, 46
`
`(Fed. Cir. 2012). Specifically, claim terms are given their ordinary and customary
`
`meanings, as would be understood by a person of ordinary skill in the art, at the
`
`time of the invention, having taken into consideration the language of the claims,
`
`the specification, and the prosecution history of record. Phillips v. AWH Corp.,
`
`415 F.3d 1303 (Fed. Cir. 2005) (en banc). In rendering its construction under
`
`Phillips, the Board does not apply a presumption of validity and does not apply a
`
`rule of construction with an aim to preserve the validity of claims. Cisco Systems,
`
`Inc. v. AIP Acquisition, LLC, Case No. IPR2014-00247, Paper 20 at 2-3 (PTAB,
`
`July 10, 2014).
`
`A.
`Person Having Ordinary Skill In The Art
`Petitioner alleges that a hypothetical person of ordinary skill in the field of
`
`the ‘552 Patent “would have had at least a B.S. degree in Electrical Engineering or
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`IPR2016-00288
`Patent 6,784,552
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`materials science (or equivalent experience), and would have at least two or three
`
`years of experience with semiconductor device fabrication and design.” Paper 2 at
`
`33-34. For purposes of this paper, Patent Owner applies Petitioner’s proposed
`
`standard without prejudice.
`
`B. Claim Construction
`The statutory and regulatory requirements that govern these proceedings
`
`require that the Petition identify “with particularity” the grounds on which the
`
`challenge to each claim is based (35 U.S.C. § 312(a)(3)), how the challenged claim
`
`is to be construed (37 C.F.R. § 42.104(b)(3)), and how the construed claim is
`
`unpatentable under the asserted grounds (37 C.F.R. § 42.104(b)(4)). Though the
`
`Petition’s claim construction section includes the proposed construction of only
`
`one term, Patent Owner believes that constructions for the following terms prove
`
`dispositive of the Petition at this preliminary stage:
`
`1.
`
`“a side of the electrically insulative spacer has an angle
`relative to the substrate surface that is either a right angle
`or an acute angle of more than 85°”
`A person of ordinary skill in the art at the time of the invention would
`
`understand that the phrase “a side of the electrically insulative spacer has an angle
`
`relative to the substrate surface that is either a right angle or an acute angle of more
`
`than 85°” in the context of the ‘552 Patent’s intrinsic record has a plain and
`
`ordinary meaning. That plain and ordinary meaning is evidenced by the consistent
`
`15
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`IPR2016-00288
`Patent 6,784,552
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`usage in the specification that the insulating spacer retains a substantially
`
`rectangular profile through the use of a low selectivity etch.1
`
`The Patentee’s characterization of “the invention” in the specification sheds
`
`light on the intended construction of the phrase “a side of the electrically insulative
`
`spacer has an angle relative to the substrate surface that is either a right angle or an
`
`acute angle of more than 85°” in which “the spacer portions of the insulating
`
`material further have substantially rectangular profiles.” Ex. 1101 at 13:55-57.
`
`The patentee specifically characterized the present invention as follows:
`
`The invention also contemplates that a portion of the etch stop layer
`
`material may remain adjacent to the spacer portion of the insulating
`
`layer following an anisotropic etch of the etch stop material with a
`
`low selectivity etch for the etch stop material relative to the insulating
`
`layer material.
`
`Ex. 1101 at 13:58-62 (emphasis added).
`
`The Patentee’s understanding of the claim term and the present invention is
`
`contrasted with the Patentee’s description of the problems of the prior art systems.
`
`The Patentee described in the specification, the problem with the prior art that the
`
`
`1 Patent Owner notes that Petitioner failed to accurately represent the term in its
`
`entirety by omitting “electrically” as recited in claim 8 of the ‘552 Patent.
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`16
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`IPR2016-00288
`Patent 6,784,552
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`present invention was aimed at solving. Specifically, the specification describes
`
`known prior art practice to form self-aligned contact regions that:
`
`The properties of the highly selective etch of the overlying etch stop
`
`layer 240 will transform a substantially rectangular spacer into a
`
`sloped spacer.
`
`Ex. 1101 at 5:11-14 (emphasis added).
`
`The Patentee consistently utilized the understanding of the claim phrase “a
`
`side of the electrically insulative spacer has an angle relative to the substrate
`
`surface that is either a right angle or an acute angle of more than 85°” to mean that
`
`the structure “retains the substantially rectangular lateral spacer profile” through an
`
`etch-stop etch that is performed in etching conditions that have a “low selectivity
`
`for etching the etch stop layer compared to the underlying insulating material” in
`
`the patent and the prosecution history to distinguish over the prior art. See Ex.
`
`1101 at 7:58-60 (“the etching conditions utilized for the etch-stop etch have a low
`
`selectivity for etching the etch stop layer compared to the underlying insulating
`
`material”); and 8:41-43 (“The phrase ‘substantially rectangular’ means that a side
`
`of the spacer has an angle relative to the substrate surface of more than 85°.”)
`
`Further, for example, during an amendment and response to office action, the
`
`patent applicants contrasted the use of highly selective etches in the prior art when
`
`they stated:
`
`17
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`Patent 6,784,552
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`The present Invention relates to a semiconductor device with
`
`well-defined contact openings. In the past, the practice with respect to
`
`forming contact openings during the fabrication of semiconductor
`
`devices, particularly self-aligned contact openings, was to use etchants
`
`with high selectivity to protect underlying regions. However, the
`
`properties of a highly selective etch of the overlying etch layer can
`
`transform a substantially rectangular spacer adjacent to the contact
`
`region into a sloped spacer. Before the conductor materials are added
`
`to the contact opening, the opening was cleaned with a sputter etchant,
`
`which can erode a portion of the sloped insulating spacer. Thus in
`
`conventional self-aligned contact structures, the diagonal thickness of
`
`the spacer, rather than the vertical thickness of the insulating layer,
`
`determined the minimum insulating layer thickness for the gate.
`
`Sloping spacers limit the number of structures that can be included on
`
`a device.
`
`The present invention avoids this problem by retaining the
`
`substantially rectangular profile of the insulating spacers. As
`
`illustrated in Figure 4K of the present specification, the spacer retains
`
`a substantially rectangular or "boxy" profile, i.e. the sides of the
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`spacer are not sloping.
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`18
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`IPR2016-00288
`Patent 6,784,552
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`Ex. 1118 at 4 (emphasis added).
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`Indeed, the Petitioner’s proposed construction of this term does not even
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`match the Petitioner’s own description of what the ‘552 Patent is directed to and
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`affirmatively claims. For example, on page 19 of the Petition (emphasis added),
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`the Petitioner states:
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`[T]he patent claims as its novel concept the use of a known etchant in
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`such a way that retains the “substantially rectangular” shape of the
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`sidewall spacer.
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`Therefore, a person of ordinary skill in the art at the time of the invention
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`would understand that the phrase “a side of the electrically insulative spacer has an
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`angle relative to the substrate surface that is either a right angle or an acute angle
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`of more than 85°” in the context of the ‘552 Patent’s intrinsic record, and
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`consistent with Phillips, means that the electrically insulative spacer retains a
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`substantially rectangular profile through the use of a low selectivity etch.
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`V. THE CHALLENGED CLAIMS ARE PATENTABLE OVER HEATH
`The Petition alleges that claims 8-12 are anticipated by Heath. The Petition
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`further alleges that claims 8-12 are obvious over Heath in view of Dennison.
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`However, as discussed in detail below, the Petitioner fails to demonstrate a
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`reasonable likelihood that Heath, alone or in combination with Dennison, discloses
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`or renders obvious the inventions recited in the challenged claims.
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`19
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`Patent 6,784,552
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`A.
`Summary of Heath
`Heath, is generally directed to a process for self-aligned contact window
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`formation in an integrated circuit. See Ex. 1103 at Abstract and 1:10-13. The
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`process in Heath “allows the simultaneous formation of self-aligned contacts to
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`field oxide, field-shield, and gate electrode edges.” Id. at Abstract. Heath Figure 2
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`depicts a semiconductor structure near completion of establishing a self-aligned
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`contact window, which illustrates a single poly process “for ease of explanation.”
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`Id. at 7:28-35. FIG. 2 is reproduced below.
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`As shown in FIG. 2, supra, oxide layer 24 has a relatively thick portion 24a
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`and a thin portion 24b. Id. at 42-43. Contact window 32 is situated between gate
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`electrodes 14 and 16, permitting contact to the source or drain. Id. at 46-48. A
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`very thick layer of BPSG (borophosphosilicate glass) dielectric 34 covers the etch
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`stop layer 10 in all places except for contact windows 30 and 32. Id. at 48-50. The
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`structure of FIG. 2 is ready for etching through etch stop layer 10 in contact
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`window openings 30 and 32 and also through the thin oxide layer 24b at opening
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`20
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`32 to open a contact window. Id. at 50-53. However, the issues surrounding
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`fabrication of a self-aligned contact window is precisely what the ‘552 Patent
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`Patent 6,784,552
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`solves.
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`0.3μm (1000-3000 (cid:1344)), which is an issue that the ‘552 Patent addresses. Heath
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`Heath discloses a large, conventional sidewall spacer on the order of 0.1-
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`states “The invented process can be used to protect a gate electrode when there is a
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`sidewall spacer… spacer 16a formed illustratively of oxide, is 0.1-0.3 μm thick
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`and remains in the structure after completion of the circuit. The thickness of
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`spacer oxide 16a is determined by considerations of optimized device
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`performance.”2 Id. at 10:12-28 (emphasis added). However, the ‘552 Patent
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`specifically addresses the limitations surrounding the fabrication of structures with
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`small feature sizes, such as self-aligned contacts. In particular, the ‘552 Patent
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`states that “eliminating alignment sensitivity for conventional small feature size
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`structures, including self-aligned contact structures, requires a final (i.e., at the
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`time of contact deposition) minimum insulating spacer of more than 500 (cid:1344) and
`preferably on the order of 1000-1500 (cid:1344) or greater to fulfill requirements for an
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`adequate process margin, complete gap fill, and device reliability.” Ex. 1101 at
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`2 Note, Heath fails to disclose any “considerations of optimized device
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`performance.”
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`21
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`6:27-33 (emphasis added). The ‘552 discloses a spacer, in a preferred
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`embodiment, having a minimum thickness of 400 (cid:1344), with spacer portions having
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`Patent 6,784,552
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`“substantially rectangular portions.” Id. at 13:53-58. Therefore, the structure
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`disclosed in Heath falls into the conventional category of structures with small
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`feature sizes required to prevent electrical ‘shorts’ that the ‘552 Patent remedies by
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`its novel fabrication process yielding a smaller and more uniformly shaped 400 (cid:1344)
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`spacer.
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`Heath Figures 8A, 8B, and 8C show the result when a misalignment of the
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`contact window occurs in accordance with the process of Heath. Ex. 1103at 9:42-
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`44. In particular, FIGS. 8A, 8B, and 8C, relate to establishing a contact window to
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`a source/drain region next to a gate electrode or field-shield electrode. Id. at 9:44-
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`47. FIGS. 8A, 8B, and 8C are reproduced below.
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`22
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`
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`As shown in FIGS 8A, 8B, and 8C, supra, Heath discloses a contact window
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`32 to source/drain area 20 has been located at the position designated by arrow 52,
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`which overlaps the left edge of field oxide 16a due to misalignment. Id. at 9:56-
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`62. Etching occurs along dotted lines 54 and stops when the etchant reaches
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`nitr