PTAB

IPR2018-00449

Applied Materials Inc v. Uri Cohen

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Petition
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1. Case Identification

2. Patent Overview

  • Title: Multiple Seed Layers For Metallic Interconnects
  • Brief Description: The ’668 patent discloses a multiple seed layer structure for fabricating metallic interconnects in semiconductor devices. The structure uses a first, "substantially conformal" seed layer and a second, thicker, "substantially non-conformal" seed layer to facilitate void-free filling of high-aspect-ratio openings via electroplating.

3. Grounds for Unpatentability

Ground 1: Obviousness over Maydan, Rathore, and Brown - Claims 1-4, 12-16, 26, 28, 29, 32, 34, 36, 37, 40-44, and 47 are obvious over Maydan in view of Rathore, further in view of Brown.

  • Prior Art Relied Upon: Maydan (Patent 6,732,633), Rathore (Patent 6,069,068), and Brown (Patent 6,187,670).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the primary reference, Maydan, discloses the fundamental structure recited in the independent claims: a substrate with a patterned insulating layer, a barrier layer, and the use of sequential seed layers followed by electroplating to fill vias. Specifically, Maydan teaches using a conformal copper wetting layer (the claimed "first seed layer") deposited by chemical vapor deposition (CVD), followed by a second seed layer deposited by physical vapor deposition (PVD). Petitioner asserted that Brown teaches that a conventional PVD process, such as sputtering, inherently results in a "substantially non-conformal" layer, meeting the patent’s specific definition (sidewall thickness less than 25% of field thickness). Rathore teaches the relative thicknesses, disclosing that for optimal performance, a thinner CVD layer should be used to minimize contamination, while a thicker PVD layer improves electromigration resistance. The combination of these teachings allegedly renders obvious the claimed structure, including a first conformal seed layer and a second, thicker, non-conformal seed layer. Dependent claims reciting specific materials (e.g., copper) and deposition methods (CVD for the first layer, PVD for the second) were argued to be expressly taught or suggested by the combination.
    • Motivation to Combine: Petitioner contended that a person of ordinary skill in the art (POSITA) would have been motivated to combine the references because they all address the same problem: improving the formation of electroplated copper interconnects. A POSITA would have looked to the teachings of Rathore and Brown to optimize the process disclosed in Maydan. Rathore provides a clear reason to make the PVD seed layer thicker than the CVD layer—to reduce contamination from the CVD process while improving electromigration resistance. Brown provides the known, conventional PVD technique to achieve the desired non-conformal profile. The combination was presented as a predictable implementation of known techniques to improve a known method.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success in combining the references. The proposed modifications—adjusting layer thicknesses and selecting conventional deposition methods as taught by Rathore and Brown for Maydan's process—were argued to be simple and predictable, leading to the expected benefits of reduced voids and improved interconnect reliability.

4. Key Claim Construction Positions

  • "Substantially Conformal Seed Layer" & "Substantially Non-conformal Seed Layer": Petitioner argued that these terms should be construed according to their express definitions in the ’668 patent specification, as the patent owner acted as his own lexicographer. The patent defines "substantially conformal" as a layer whose sidewall thickness is 25-100% of its field thickness, and "substantially non-conformal" as a layer whose sidewall thickness is less than 25% of its field thickness. Petitioner asserted these definitions are not standard in the art and are critical to the invalidity analysis, as the prior art is alleged to meet these specific, patent-defined numerical ranges.

5. Key Technical Contentions (Beyond Claim Construction)

  • Priority Date Entitlement: Petitioner contended that the challenged claims are not entitled to a priority date earlier than their December 4, 2000 filing date. The argument was that the parent applications fail to provide adequate written description for the specific numerical ranges (25-100% and <25%) used to define "substantially conformal" and "substantially non-conformal." Because these definitions were introduced for the first time in the application that led to the ’668 patent, Petitioner argued that the patent impermissibly broadened the scope of the invention and cannot claim priority from the earlier applications, making more prior art available for the challenge.

6. Relief Requested

  • Petitioner requests institution of an inter partes review (IPR) and cancellation of claims 1-4, 12-16, 26, 28, 29, 32, 34, 36, 37, 40-44, and 47 of the ’668 patent as unpatentable under 35 U.S.C. §103.