PTAB

IPR2018-00445

Applied Materials Inc v. Uri Cohen

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Multiple Seed Layers for Metallic Interconnects
  • Brief Description: The ’226 patent discloses a method for making metallic interconnects in semiconductor fabrication. The method involves forming a composite plating seed layer by sequentially depositing a "substantially conformal seed layer" (e.g., via Chemical Vapor Deposition) and a "substantially non-conformal seed layer" (e.g., via Physical Vapor Deposition) before electroplating copper to fill the interconnect structure.

3. Grounds for Unpatentability

Ground 1: Obviousness over Hsiung - Claims 1, 21-24, and 27 are obvious over Hsiung.

  • Prior Art Relied Upon: Hsiung (Application # 2002/0045345).
  • Core Argument for this Ground: Petitioner argued that Hsiung teaches every element of the challenged claims. Hsiung describes a method to enhance copper damascene performance by using a multiple seed layer structure to solve problems of poor sidewall coverage and voids associated with single-layer PVD techniques.
    • Prior Art Mapping: Petitioner asserted that Hsiung’s method maps directly to the limitations of independent claim 1. Hsiung teaches depositing a conformal TiN layer using Chemical Vapor Deposition (CVD), which Petitioner contended meets the ’226 patent’s definition of a “substantially conformal seed layer” (sidewall thickness of 25-100% of field thickness), as CVD was known to produce uniform, highly conformal films. Hsiung then teaches depositing a copper seed layer using Physical Vapor Deposition (PVD) over the TiN layer. Petitioner argued this PVD layer, which Hsiung describes as having “discontinuities,” inherently meets the definition of a “substantially non-conformal seed layer” (sidewall thickness <25% of field thickness), as PVD was well-known to produce such results. Hsiung further teaches that its PVD copper layer is thicker than its CVD TiN layer and that the structure is subsequently filled by electroplating copper. Petitioner also mapped Hsiung’s disclosure of depositing a barrier layer and removing excess material via chemical mechanical polishing (CMP) to the dependent claims.

Ground 2: Obviousness over Hsiung in view of Brown - Claim 28 is obvious over Hsiung in view of Brown.

  • Prior Art Relied Upon: Hsiung (Application # 2002/0045345) and Brown (Patent 6,187,670).
  • Core Argument for this Ground: Petitioner argued that claim 28, which depends from claim 27 and requires the barrier layer to be deposited by a CVD technique, would have been obvious by modifying Hsiung’s process with the teachings of Brown.
    • Prior Art Mapping: While Hsiung teaches depositing its barrier layer using PVD, it explicitly recognizes the shortcomings of PVD, such as poor sidewall coverage. Brown was cited for its teaching that a barrier layer can be deposited using CVD to achieve a more conformal layer, directly addressing the problem identified in Hsiung.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) reviewing Hsiung would have been motivated to improve the performance of its PVD barrier layer. Petitioner contended a POSITA would have looked to known, predictable solutions and found Brown’s teaching of using CVD for barrier layers to be an obvious modification to enhance conformality and overcome the deficiencies of PVD.
    • Expectation of Success: Because depositing a barrier layer using CVD was a well-known and predictable technique chosen from a finite number of solutions to improve film uniformity, a POSITA would have had a reasonable expectation of success in applying Brown’s teaching to Hsiung’s method.

Ground 3: Obviousness over Hsiung in view of Sherman - Claim 29 is obvious over Hsiung in view of Sherman.

  • Prior Art Relied Upon: Hsiung (Application # 2002/0045345) and Sherman (Patent 6,342,277).
  • Core Argument for this Ground: Petitioner argued that claim 29, which depends from claim 27 and requires the barrier layer to be deposited by an Atomic Layer Deposition (ALD) technique, would have been obvious by modifying Hsiung with the teachings of Sherman.
    • Prior Art Mapping: Sherman was cited for its disclosure of using ALD to deposit various films, including TiN barrier layers. Sherman teaches that ALD produces "perfectly conformal" films, making it an ideal technique for addressing the poor sidewall coverage issue associated with Hsiung’s PVD barrier layer.
    • Motivation to Combine: Similar to the motivation in Ground 2, a POSITA seeking to improve the non-uniform barrier layer in Hsiung would be motivated to employ Sherman’s ALD technique. ALD was a known method for achieving superior conformality, and its application to Hsiung’s process would directly address Hsiung’s stated goal of improving layer performance.
    • Expectation of Success: Applying Sherman’s known ALD technique to deposit Hsiung's barrier layer was presented as the application of a known technique to a known method to achieve a predictable result. Therefore, a POSITA would have had a reasonable expectation of successfully creating a more robust and uniform barrier layer.

4. Key Claim Construction Positions

  • "substantially conformal seed layer" and "substantially non-conformal seed layer": Petitioner argued that the patent owner acted as his own lexicographer by providing explicit, unconventional definitions for these terms in the specification of the ’226 patent.
    • Petitioner asserted the term "substantially conformal seed layer" must be construed to mean "a layer whose thickness on the sidewalls of an opening (at about mid-depth) is about 25-100% of its thickness on the field."
    • Petitioner asserted the term "substantially non-conformal seed layer" must be construed to mean "a layer whose thickness on the sidewalls of an opening (at about mid-depth) is less than about 25% of its thickness on the field."
  • These constructions were central to Petitioner’s argument that the prior art processes, which used standard CVD and PVD techniques, would inherently produce layers meeting these specific numerical definitions.

5. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1, 21-24, and 27-29 of the ’226 patent as unpatentable under 35 U.S.C. §103.