Petition for Inter Partes Review of U.S. 5,652,084
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`UNITED STATES PATENT AND TRADEMARK OFFICE
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`
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`BEFORE THE PATENT TRIAL AND APPEAL BOARD
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`SAMSUNG ELECTRONICS CO., LTD
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`Petitioner
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`v.
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`DSS TECHNOLOGY MANAGEMENT, INC.
`Patent Owner
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`
`
`
`U.S. Patent No. 5,652,084
`Title: METHOD FOR REDUCED PITCH LITHOGRAPHY
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`
`
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`Inter Partes Review No. IPR2014-01493
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`
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`CORRECTED PETITION FOR INTER PARTES REVIEW OF
`U.S. PATENT NO. 5,652,084
`CHALLENGING CLAIMS 1-16
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`Petition for Inter Partes Review of U.S. 5,652,084
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`TABLE OF CONTENTS
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`I.
`Introduction .................................................................................................. 1
`II. Mandatory Notices ........................................................................................ 1
`A.
`Real Party-in-Interest .......................................................................... 1
`B.
`Related Matters ................................................................................... 1
`C.
`Lead and Back-up Counsel and Service Information........................... 2
`III. Grounds for Standing .................................................................................... 2
`IV. Relief Requested ........................................................................................... 2
`V.
`Summary of the 084 Patent ........................................................................... 3
`A.
`Summary of the Related Technology and the 084 Patent .................... 3
`B.
`The Prosecution History...................................................................... 6
`C.
`Claim Construction ............................................................................. 9
`1.
`Imaging Layer........................................................................... 9
`2.
`Stabilizing ............................................................................... 10
`3.
`Single Patterned Layer ............................................................ 10
`4.
`Disposable Post....................................................................... 11
`5.
`PRIST ..................................................................................... 12
`6.
`Second Feature Distinct From the First Feature ...................... 13
`VI. The Prior Art of the Present Petition ........................................................... 13
`A. Anticipation References .................................................................... 13
`1.
`Jap. Patent App. No. HEI 4[1992]-71222 (“Jinbo”)
`(Samsung-1013) (English Translation Samsung-1005) ........... 14
`2.
`U.S. Patent No. 5,667,940 (“Hsue”) (Samsung-1006) ............. 16
`Obviousness Combination References .............................................. 19
`1. McColgin (U.S. Patent No. 4,931,351) (Samsung-1007)......... 19
`2. Matthews (U.S. Patent No. 4,548,688) (Samsung-1008) ......... 20
`3.
`Cooper (U.S. Patent No. 5,158,910) (Samsung-1009) ............. 21
`VII. Identification of Challenges ........................................................................ 23
`A.
`Challenged Claims ............................................................................ 23
`B.
`Statutory Grounds for Challenges ..................................................... 23
`C. Obviousness Rationales .................................................................... 23
`1.
`Substitution of Known Stabilization Techniques to
`Obtain Predictable Results (Claims 8, 9, 10, and 11) .............. 23
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`B.
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`Petition for Inter Partes Review of U.S. 5,652,084
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`D.
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`2. Motivation to Combine the Prior Art References to Use
`the Patterned Photoresist as a Disposable Post (Claims 13
`and 14) .................................................................................... 26
`Challenges ........................................................................................ 26
`1.
`Claims 1-8, 12, and 15-16 are anticipated under § 102(b)
`by Jinbo .................................................................................. 26
`Claim 9 is obvious under § 103(a) over Jinbo in view of
`McColgin ................................................................................ 39
`Claims 10 and 11 are obvious under § 103(a) over Jinbo
`in view of Matthews ............................................................... 40
`Claims 13 and 14 are obvious under § 103(a) over Jinbo
`in view of Cooper ................................................................... 41
`Claims 1-7, 10, 12, and 15-16 are anticipated under §
`102(e) by Hsue........................................................................ 44
`Claim 8 is obvious under § 103(a) over Hsue in view of
`Jinbo ....................................................................................... 55
`Claim 9 is obvious under § 103(a) over Hsue in view of
`McColgin ................................................................................ 56
`Claim 11 is obvious under § 103(a) over Hsue in view of
`Matthews ................................................................................ 56
`Claims 13 and 14 are obvious under § 103(a) over Hsue
`in view of Cooper ................................................................... 57
`VIII. Conclusion .................................................................................................. 60
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`2.
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`3.
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`4.
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`5.
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`6.
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`7.
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`8.
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`9.
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`Petition for Inter Partes Review of U.S. 5,652,084
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`SAMSUNG’S EXHIBIT LIST
`September 12, 2014
`The 084 Patent, U.S. Patent No. 5,652,084
`Prosecution History of U.S. Patent No.
`5,652,084
`IBM Technical Disclosure, volume 32,
`number 8A (January 1990) (Disclosure 1)
`The 061 Patent, U.S. Patent No. 5,710,061
`Jinbo, Japanese Patent App. No. 04-71222
`(English Translation with Certification)
`Hsue, U.S. Patent No. 5,667,940
`McColgin, U.S. Patent No. 4,931,351
`Matthews, U.S. Patent No. 4,548,688
`Cooper, U.S. Patent No. 5,158,910
`W.H.-L. Ma., Plasma Resist Image
`Stabilization Technique (PRIST), IEEE
`Electron Devices Meeting, 1980 International,
`vol. 26, pp. 574-76, 1980
`Declaration of Bruce Smith
`Curriculum Vitae of Bruce Smith
`Jinbo, Japanese Patent App. No. 04-71222
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`Samsung-1001
`Samsung-1002
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`Samsung-1003
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`Samsung-1004
`Samsung-1005
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`Samsung-1006
`Samsung-1007
`Samsung-1008
`Samsung-1009
`Samsung-1010
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`Samsung-1011
`Samsung-1012
`Samsung-1013
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`iii
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`Petition for Inter Partes Review of U.S. 5,652,084
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`I.
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`INTRODUCTION
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`Pursuant to the provisions of 35 U.S.C. §§ 311-319, Petitioner Samsung
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`Electronics Co., Ltd. (“Samsung”) hereby petitions the Patent Trial and Appeal
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`Board to institute an inter partes review of claims 1-16 (all claims) of United
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`States Patent No. 5,652,084 (“the 084 Patent,” Samsung-1001) that issued on July
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`29, 1997, to James M. Cleeves. According to USPTO records, the 084 Patent is
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`currently assigned to DSS Technology Management, Inc. The 084 Patent is
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`currently the subject of the petition for inter partes review by Taiwan
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`Semiconductor Manufacturing Company, Ltd., IPR2014-01030 (“IPR-1030”),
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`filed on June 24, 2014. This petition includes challenges based on the same
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`primary reference as IPR-1030 (Japanese Patent Application No. HEI 4[1992]-
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`71222 (“Jinbo”) (Samsung-1013) as well as challenges based on an additional
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`primary reference (U.S. Patent No. 5,667,940 (“Hsue”)) (Samsung-1006).
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`II. MANDATORY NOTICES
`A. Real Party-in-Interest
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`The real party in interest is Samsung.
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`B. Related Matters
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`As of the filing date of this petition and to the best knowledge of Samsung, the
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`084 Patent is involved in the following litigation: (1) Petition for Inter Partes
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`Review by Taiwan Semiconductor Manufacturing Company, Ltd., IPR2014-
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`Petition for Inter Partes Review of U.S. 5,652,084
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`01030, filed on June 24, 2014; and (2) DSS Technology Mgmt., Inc. v. Taiwan
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`Semiconductor Manufacturing Company, Ltd. et al., 2-14-CV-00199 (EDTX).
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`C. Lead and Back-up Counsel and Service Information
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`Lead Counsel
`Christopher T. Marando
`Weil, Gotshal & Manges LLP
`1300 Eye Street NW, Suite 900
`Washington, DC 20005-3314
`Phone: (202) 682-7094
`Fax: (202) 857-0940
`christopher.marando@weil.com
`USPTO Customer No. 506499
`USPTO Reg. No. 67,898
`
`
`
`Back-up Counsel
`Brian E. Ferguson
`Weil, Gotshal & Manges LLP
`1300 Eye Street NW, Suite 900
`Washington, DC 20005-3314
`Phone: (202) 682-7516
`Fax: (202) 857-0940
`brian.ferguson@weil.com
`USPTO Customer No. 506499
`USPTO Reg. No. 36,801
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`Please address all correspondence to lead and back-up counsel. Samsung also
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`consents to electronic service by email.
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`III. GROUNDS FOR STANDING
`Samsung certifies that the 084 Patent for which review is sought is available for
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`inter partes review and that Samsung is not barred or estopped from requesting
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`inter partes review challenging the patent claims on the grounds identified in the
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`petition.
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`IV. RELIEF REQUESTED
`Samsung asks that the Board review the accompanying prior art and analysis,
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`institute a trial for inter partes review of claims 1-16 (all claims) of the 084 Patent,
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`and cancel those claims as unpatentable.
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`Petition for Inter Partes Review of U.S. 5,652,084
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`V.
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`SUMMARY OF THE 084 PATENT
`The full statement of the reasons for the relief requested is as follows:
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`A. Summary of the Related Technology and the 084 Patent1
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`Photolithography (or “lithography”) is the use of light or other radiation to form
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`a pattern in a material. Photolithographic techniques are commonly used in
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`semiconductor fabrication to form the minute features of modern integrated circuit
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`devices. As the 084 Patent describes, a typical photolithography process involves
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`depositing photoresist over a layer of material to be patterned, exposing the
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`photoresist to ultraviolet radiation through a mask, developing the photoresist to
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`form a patterned photoresist layer over the layer of material to be patterned, and
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`subsequently utilizing the patterned photoresist layer to etch the underlying layer to
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`be patterned. See Samsung-1001, 084 Patent at 1:19-27.
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`Driven in part by the demand for smaller and more efficient devices, circuit
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`fabrication presses the limits of photolithography, and many circuit features are
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`sized at or near the minimum lithographic resolution. The 084 Patent recognizes
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`the limits imposed by conventional lithography and the potential for alleged
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`lithographic improvements to enable the fabrication of integrated circuit devices
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`with relatively smaller sizes. Id. at 1:14-35, 12:28-38.
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`
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`1 The following description of the 084 Patent and the related technology is
`substantially similar to the description provided in IPR-1030.
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`Petition for Inter Partes Review of U.S. 5,652,084
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`The 084 Patent is particularly concerned with reducing the spacing between
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`adjacent features (i.e., photoresist shapes) in a single patterned layer of photoresist.
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`To reduce the spacing, the 084 Patent describes that a single patterned layer of
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`photoresist is formed through two exposures to radiation. In particular, the 084
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`Patent teaches that a first layer of photoresist (imaging layer 220) is formed over a
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`material layer 210 and exposed using a lithographic mask as shown in FIG. 2,
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`reproduced below.
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`The 084 Patent states that “[t]he radiation serves to render soluble in a suitable
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`developer that portion of imaging layer 220 exposed to radiation through clear
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`features 221 and 223,” while the “portion of imaging layer 220 that has not been
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`exposed to radiation remains relatively insoluble in the developer.” Id. at 3:66-4:4.
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`The first imaging layer 220 is then developed, leaving a first patterned layer 232
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`with a photoresist feature as shown in FIG. 3, reproduced below.
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`Petition for Inter Partes Review of U.S. 5,652,084
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`The first patterned layer 232 is “stabilized” before applying the second resist.
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`With respect to this stabilization, the 084 Patent teaches the following:
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`First patterned layer 232 may be stabilized to withstand subsequent
`lithographic processing steps. First patterned layer 232 may be
`stabilized to withstand chemical transformation as a result of any
`subsequent exposure to radiation, for example. First patterned layer
`232 may also be stabilized to withstand dissolution by solvents during
`a subsequent spin-on of photoresist, for example. First patterned layer
`232 may further be stabilized to withstand dissolution by a
`subsequent developer, for example.
`Id. at 4:34-42.2 After the first patterned layer 232 has been stabilized, a second
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`resist (second imaging layer 240) is formed over the first patterned layer 232 and
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`exposed in a lithographic process. The second imaging layer 240 is then
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`developed, which leaves some photoresist features from the first imaging layer
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`(e.g., feature 232) and some photoresist features (e.g., features 251 and 253) from
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`the second imaging layer. This is shown in FIGS. 4 and 5, reproduced below.
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`2 Emphases in this petition are added unless otherwise noted.
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`5
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`Petition for Inter Partes Review of U.S. 5,652,084
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`The 084 Patent refers to this structure having adjacent features from two
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`different imaging layers as a “single patterned layer.” Id. at 7:36-40. Subsequent
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`processing, such as etching layer 210, takes advantage of the shape of the
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`remaining features within the single patterned layer to process portions of the
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`underlying layers selectively. Alternatively, the features of single patterned layer
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`could be utilized as a disposable post (described below). The 084 Patent teaches
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`that “features for the resulting single patterned layer, such as the patterned layer
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`illustrated in FIGS. 5, 11, and 16 respectively, may be formed relatively closer to
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`one another” when compared with a single exposure process. Id. at 12:28-34.
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`B. The Prosecution History
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`The 084 Patent issued on July 29, 1997, from U.S. Patent App. No. 08/740,145
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`(“the 145 Application”), filed by James M. Cleeves on October 22, 1996. The 084
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`Patent is a continuation of U.S. Patent Application No. 08/361,595 (“the 595
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`Application”), filed on December 22, 1994 (now abandoned). The file wrapper of
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`the 595 Application was used as the basis for 145 Application, and the 145
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`Application includes all amendments made to the 595 Application. During
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`prosecution of the 595 Application, the claims were repeatedly rejected in view of
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`the prior art. Of particular interest, Applicant amended claim 1 to recite, for
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`example, “a first patterned layer having a first feature” and “a second patterned
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`layer having a second feature distinct from the first feature,” “wherein the first and
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`Petition for Inter Partes Review of U.S. 5,652,084
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`second features which are formed relatively closer to one another than is possible
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`through a single exposure to radiation.” Samsung-1002 at pp. 129-30, Applicant’s
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`Amendment dated 9-24-1996 at pp. 1-2. Regarding the “second feature distinct
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`from the first feature,” Applicant’s amendments were made to distinguish IBM
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`Technical Disclosure, volume 32, number 8A (January 1990) (Disclosure 1). For
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`reference, the features of Disclosure 1 relating to Applicant’s arguments are shown
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`below:
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`Samsung-1003, Disclosure 1, Fig. 1
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`Further, Disclosure 1 provides the following description of Figure 1:
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`[A] first photoresist layer 2 is deposited on substrate 4. Openings
`having width A and width B are formed in photoresist 2 by exposure
`to a first mask and development. Remaining photoresist 2 is then
`hardened, e.g., by a heat treatment. Next, photoresist 6 is applied and
`exposed to a second mask whereupon an opening having width C is
`created by exposure and development. A patterned defined by
`coincidence of openings having width A and C (D) can then be etched
`in substrate 4.
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`Samsung-1003, Disclosure 1, at 219. Applicant distinguished Disclosure 1 as
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`follows:
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`Petition for Inter Partes Review of U.S. 5,652,084
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`Disclosure 1 forms overlapping openings A, C, D, and E in order to
`incorporate three sets of patterns in two photomasking steps. Thus,
`Disclosure 1 teaches away from amended claim 1, because openings
`A, C, D, and E are overlapping non-distinct features … There is no
`teaching in Disclosure 1 to motivate A POSITA in the art to perform a
`subsequent patterning of photoresist 6 to form a second distinct
`feature which is relatively closer to openings A or B than is possible
`through a single exposure to radiation. Furthermore, there is no
`teaching in Disclosure 1 that openings C, D, or E are formed relatively
`closer to opening B than is possible in a single exposure to radiation.
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`Samsung-1002 at pp. 132-33, Applicant’s Amendment dated 9-24-1996 at pp. 4-5.
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`Applicant’s amendments were received but not entered in the prosecution of the
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`595 Application. However, upon being entered in the 145 Application, the
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`Examiner allowed the claims, stating that Disclosure 1 “does not teach the
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`formation of two distinct features in the two layers,” and a second cited reference
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`“forms two distinct patterns in two different layers[,] but the patterns are not
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`formed closer to one another than possible in a single exposure.” Id. at pp. 157-58,
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`Notice of Allowance dated 2-10-1997 at pp. 2-3. Thus, in light of Applicant’s
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`arguments and the Examiner’s reasons for allowance, the “second feature distinct
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`from the first feature” requires that the second feature be spatially separated from
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`the first feature on the x axis.
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`Petition for Inter Partes Review of U.S. 5,652,084
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`C. Claim Construction
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`For a non-expired patent, a claim subject to an IPR is interpreted in a manner
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`that is consistent with the broadest reasonable interpretation in light of the
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`specification. See 37 C.F.R. § 42.100(b). This means that the words of the claim
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`are given their plain meaning unless that meaning is inconsistent with the
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`specification. In re Zletz, 893 F.2d 319, 321 (Fed. Cir. 1989). For expired patents,
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`the claims are interpreted in accordance with the principles outlined in Phillips v.
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`AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (en banc). See In re Rambus, Inc., 753
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`F.3d 1253, 1256 (Fed. Cir. 2014). The 084 Patent will expire on December 22,
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`2014, which may occur prior to the Board’s institution decision. Accordingly, this
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`petition proposes constructions below consistent with the standard for both non-
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`expired and expired patents. These constructions are proposed for the sole purpose
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`of this petition and to comply with 37 C.F.R. §§ 42.100(b) and 42.104(b)(3).
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`1.
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`Imaging Layer
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`The claims recite first and second imaging layers. According to the 084 Patent,
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`an imaging layer may include “a suitable positive photoresist,” “a suitable negative
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`photoresist,” “a suitable radiation-sensitive polyimide,” or “other suitable
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`radiation-sensitive materials.” Samsung-1001, 084 Patent at 3:34-42. Accordingly,
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`the term imaging layer should be construed to mean a photoresist or other
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`radiation-sensitive material. See Samsung-1011, Smith Decl. ¶ 32.
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`Petition for Inter Partes Review of U.S. 5,652,084
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`2.
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`Stabilizing
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`The claims refer to stabilizing the first patterned layer. The 084 Patent discloses
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`stabilizing a patterned imaging layer “to withstand subsequent lithographic
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`processing steps.” Samsung-1001, 084 Patent at 4:34-35. As described above, the
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`084 Patent states that the first patterned layer “may” be stabilized to withstand
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`“chemical transformation as a result of any subsequent exposure to radiation,”
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`“dissolution by solvents,” or “dissolution by a subsequent developer.” See id. at
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`4:35-42. These three examples are repeated throughout the specification. See, e.g.,
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`id. at 5:12-22, 5:32-36, 8:51-57. Thus, the term stabilizing means performing a
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`process that renders a material able to withstand subsequent processing steps,
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`such as exposure to radiation, exposure to a solvent, or exposure to a developer.3
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`See Samsung-1011, Smith Decl. ¶ 33.
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`3.
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`Single Patterned Layer
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`The claims recite that “the second patterned layer and the first patterned layer
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`form a single patterned layer.” The 084 Patent teaches that “[t]his single patterned
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`layer is formed from the patterning of imaging layer 220 and the subsequent
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`
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`3 To the extent the Board finds that stabilizing requires rendering the material able
`to withstand all three subsequent processing steps, this is disclosed by both primary
`references discussed below as well as each of the combination references for the
`dependent claims concerning stabilization. See also Samsung-1011, Smith Decl. ¶
`40.
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`Petition for Inter Partes Review of U.S. 5,652,084
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`patterning of imaging layer 240,” Samsung-1001, 084 Patent at 7:36-40. This is
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`illustrated in FIG. 5 of the 084 Patent, reproduced below.
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`FIG. 5 shows that the single patterned layer is one layer that includes features
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`
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`from the first patterned layer (e.g., feature 232) and features from the second
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`patterned layer (e.g., features 251 and 253). Thus, the recited single patterned layer
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`should be construed to mean a single layer of patterned features, which may be
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`formed from one or more imaging layers. See Samsung-1011, Smith Decl. ¶ 35.
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`4.
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`Disposable Post
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`Claim 13 recites “patterning the first imaging layer in accordance with a first
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`pattern to form a first patterned layer having a first disposable post.” The
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`specification of the 084 Patent discloses that “disposable posts are removed to
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`form openings for a subsequent layer, such as a contact, via, or interconnect layer
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`for example” and refers to U.S. App. No. 08/179,615 for more details. Samsung-
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`1001, 084 Patent at 12:53-62. U.S. App. No. 08/179,615 issued (through a
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`continuation) as U.S. Patent No. 5,710,061 (Samsung-1004, the “061 Patent”).
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`Samsung-1004, 061 Patent. The 061 Patent describes a post as a patterned
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`material—such as a photoresist—that may be surrounded by a second material.
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`Petition for Inter Partes Review of U.S. 5,652,084
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`The post may then be removed to form an opening in the second material.
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`Samsung-1004, 061 Patent at 2:43-49. In the embodiments of Figs. 2A-2E, the 061
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`Patent teaches “photosensitive material 220 has been patterned to form post 221
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`over diffusion region 201 so as to later form a contact opening in an insulative
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`layer to be formed over the surface of the wafer.” Id. at 5:39-42.
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`Samsung-1004, 061 Patent, FIG. 2C
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`Thus, the term disposable post should be construed to mean a patterned feature
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`that may be surrounded by another layer of material, and that may be removed to
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`define an opening such as a contact, via, or interconnect layer opening. See
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`Samsung-1011, Smith Decl. ¶ 37.
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`5.
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`PRIST
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`Claim 8 requires stabilization through a PRIST technique. The specification of
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`the 084 Patent discloses that “[a]s one example, a pirst [sic] technique may be used
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`to form a carbon fluorine (CF4) skin over first patterned layer 232 by exposing the
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`photoresist to a fluorine ambient.” Samsung-1001, 084 Patent at 4:67-5:3. Plasma
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`Resist Image Stabilization Technique (or PRIST) was a well-known technique for
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`stabilizing photoresist in use since at least the early 1980s. See, e.g., Samsung-
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`1010, W.H.-L. Ma., Plasma Resist Image Stabilization Technique (PRIST), IEEE
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`Petition for Inter Partes Review of U.S. 5,652,084
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`Electron Devices Meeting, 1980 Int’l, vol. 26, pp. 574-75, 1980. Thus, a PRIST
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`technique should be construed as a Plasma Resist Image Stabilization Technique,
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`including techniques such as the fluorine plasma stabilization described in the
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`084 Patent. See Samsung-1011, Smith Decl. ¶ 38.
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`6.
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`Second Feature Distinct From the First Feature
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`Claim 1 requires that the second patterned layer have “a second feature distinct
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`from the first feature.” The term “distinct” is not defined in the specification. As
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`discussed above, this term was added during prosecution to distinguish the prior
`
`art. Specifically, Applicant added this limitation to distinguish Disclosure 1’s
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`“overlapping non-distinct features.” See Samsung-1002 at pp. 132-33, Applicant’s
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`Remarks dated 9-24-1996, at pp. 4-5. Meanwhile, dependent claim 12 requires that
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`“the first and second features do not overlap.” Notwithstanding claim 12,
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`Applicant’s arguments during prosecution overcome any claim differentiation
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`argument that the first and second features may overlap. Thus, in view of the
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`Applicant’s arguments, a second feature distinct from the first feature is a second
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`patterned feature that is spatially separated from the first feature on the x axis.
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`This is also consistent with the plain meaning of a “distinct” feature. See Samsung-
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`1011, Smith Decl. ¶ 39.
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`VI. THE PRIOR ART OF THE PRESENT PETITION
`A. Anticipation References
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`13
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`Petition for Inter Partes Review of U.S. 5,652,084
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`1.
`
`Jap. Patent App. No. HEI 4[1992]-71222 (“Jinbo”) (Samsung-
`1013) (English Translation Samsung-1005)4
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`Jinbo is directed to a double patterning technique for forming shapes that are
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`closer than is possible using a comparable single exposure technique. Further
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`reference is made to a certified English translation of the published Japanese Patent
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`Application (Samsung-1005, “Jinbo”). Just like the 084 Patent, Jinbo recognizes
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`that single patterning techniques have been limited by the minimum resolvable
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`distance, an optical property of a photolithographic system. In order to reduce
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`device spacing beyond this resolution limit, Jinbo discloses exposing and
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`developing a first resist to form a first resist pattern. The first resist is then exposed
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`to a plasma to fix the resist and render it “insoluble” to the solvents and developers
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`used in forming subsequent resists (examples 2 and 3 of subsequent processing
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`steps described in the 084 Patent). Specifically, Jinbo discloses a PRIST
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`technique—i.e., exposing the first resist to a fluorine-containing plasma. See
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`Samsung-1005, Jinbo at p. 5; Samsung-1011, Smith Decl. ¶ 45. Thus, Jinbo’s
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`insoluble-ization process is describing stabilization as that term is used in the 084
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`Patent because it allows the first photoresist layer to withstand subsequent
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`processing steps, such as exposure to a solvent and/or exposure to a developer. In
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`addition, a person of ordinary skill in the art (“POSITA”) would understand that
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`4 The following description of Jinbo is substantially similar to the description
`provided in IPR-1030.
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`such a technique would also make the resist able to withstand subsequent exposure
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`to radiation, the third and final exemplary processing step. Samsung-1011, Smith
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`Decl. ¶ 45. Thus, the stabilization described in Jinbo enables the photoresist to
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`withstand all three subsequent processing steps described in the 084 Patent. To the
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`extent that DSS argues that Jinbo’s and the 084 Patent’s processes are different,
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`using a stabilization process as recited in the claims would have been obvious.
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`A second resist is then formed on the patterned first resist. The second resist is
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`exposed and developed to form a second resist pattern interleaved with the first
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`resist pattern. The two resist patterns are then used to etch an underlying material
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`layer. Jinbo discloses that this technique provides reduced shape spacing than
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`single resist techniques using the same lithographic system. To compare the 084
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`Patent and Jinbo, FIG. 5 from the 084 Patent is reproduced below next to FIG. 1(e)
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`from Jinbo. As annotated, both figures show a single patterned layer with a first
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`feature from a first patterned layer and a second feature from a second patterned
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`layer that is distinct from the first feature, as recited in claim 1 of the 084 Patent.
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`Claim 1 also recites that the first and second features ... are formed relatively
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`closer to one another than is possible through a single exposure to radiation. Jinbo
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`discloses the same thing: “[W]hen the resolution limit is 0.4 µm, a 0.3 µm line and
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`space pattern, which exceeds the resolution limit of the system, can be obtained by
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`applying the pattern forming method of this invention to the system.” Samsung-
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`1005, Jinbo at p. 6.
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`2.
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`U.S. Patent No. 5,667,940 (“Hsue”) (Samsung-1006)
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`The application that led to the issuance of Hsue was a continuation of an
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`application filed on May 11, 1994. Therefore, Hsue is prior art to the 084 Patent
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`under 35 U.S.C. § 102(e). Hsue was not identified to the Examiner during the
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`prosecution of the 084 Patent. Hsue discloses that a layer 12 to be etched is
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`deposited over a substrate 10. A first layer of photoresist is deposited over the layer
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`to be etched, patterned using a mask, and developed to produce a first patterned
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`layer 14. The resulting first patterned layer 14 has openings of the size R+2M,
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`where R is the line width and M is the misalignment tolerance. See Samsung-1006,
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`Hsue at 2:19-37. The first patterned layer 14 is shown in Figure 2.
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`Subsequently, the first patterned layer is baked (i.e., heated) using an ultraviolet
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`(UV) baking process at a temperature between about 140° to 160°C to prevent it
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`from being removed during subsequent development steps. See Samsung-1006,
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`Hsue at 2:38-42; 2:48-50. Thus, the first patterned layer is stabilized to withstand
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`subsequent developers (example 3) by simultaneously heating the layer as well as
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`exposing it to UV radiation. A POSITA would know that, so long as the UV
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`radiation is in the sub-320 nm range (UV light has a wavelength between 10 nm
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`and 400 nm, see Smith Decl. ¶ 47 n.4), the UV radiation would also cause the
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`photoresist to crosslink. See Samsung-1011, Smith Decl. ¶ 47 (citing Samsung-
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`1008, Matthews at 3:57-61). A POSITA would also know that when photoresist
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`“crosslinks,” it becomes able to withstand to radiation, solvents, and developers.
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`Thus, the stabilization described in Hsue enables the photoresist to withstand all
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`three subsequent processing steps described in the 084 Patent. See id. ¶ 47.
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`A second photoresist layer is then deposited in the openings between the
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`features of the first patterned layer. The second photoresist layer is patterned
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`through a mask 20 and developed to produce a second patterned layer 18. See
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`Samsung-1006, Hsue at 2:43-47. This is shown in Figure 3:
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`Following development of the second patterned layer, the features of the first
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`patterned layer (14) and the features of the second patterned layer (18) are distinct
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`(i.e., spatially separated on the x axis) and combine to form a single patterned
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`layer. This is shown in Figure 4:
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`The resulting features of the single patterned layer are a distance M apart
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`instead of a distance R as in the prior art. See id. at 2:51-53. Because M is much
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`smaller than R, the spacing of the features is reduced dramatically through the use
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`of the double exposure technique as compared to the prior art technique of a single
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`exposure to radiation. See id. at 2:53-55. See also id. at 1:22-31 (describing the
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`prior art technique of patterning photoresist through a single exposure to radiation).
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`A comparison between the result of the process of the 084 Patent and the process
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`of Hsue is provided below:
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`Dependent claim 10 requires that the stabilizing step of claim 1 include
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`exposing the first patterned layer to radiation and heating the first patterned layer.
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`This is disclosed in Hsue, but not Jinbo. Thus, Hsue is not cumulative because, as
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`further described below, Hsue anticipates claim 10 while Jinbo does not.
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`B. Obviousness Combination References
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`1. McColgin (U.S. Patent No. 4,931,351) (Samsung-1007)
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`McColgin issued on June 5, 1990, and therefore is prior art under 35 U.S.C. §
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`102(b). McColgin was cited prior art to the 084 Patent. McColgin discloses a
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`silylation technique (silylation is a stabilization technique required by dependent
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`claim 9 of the 084 Patent) to impart etch resistance to a layer of developed
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`photoresist. See, e.g., Samsung-1007, McColgi