PTAB

IPR2018-00447

Applied Material Inc v. Uri Cohen

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Multiple Seed Layers for Metallic Interconnects
  • Brief Description: The ’052 patent describes methods for making metallic interconnects in semiconductor fabrication. The technology focuses on using a composite seed layer structure, comprising two sequentially deposited seed layers, to facilitate the void-free electrochemical filling of high-aspect-ratio openings (vias and trenches) with copper.

3. Grounds for Unpatentability

Ground 1: Anticipation Under §102 - Claims 4-6, 8-10, 13-18, 26, 27, 29-34, 53, 54, 56-58, and 65-68 are anticipated under 35 U.S.C. §102 by Hsiung.

  • Prior Art Relied Upon: Hsiung (Application # 2002/0045345)
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Hsiung, which describes a method for enhancing copper damascene processes, discloses every element of the challenged claims. Hsiung teaches forming a patterned insulating layer with openings, depositing a barrier layer, and then sequentially depositing two distinct seed layers before a final electroplating step. Specifically, Hsiung discloses depositing a first seed layer of Titanium Nitride (TiN) using chemical vapor deposition (CVD) over the barrier layer. Subsequently, Hsiung deposits a second seed layer of copper (Cu) using physical vapor deposition (PVD) over the first TiN seed layer. This two-layer structure is then used to facilitate the complete filling of the openings via electrochemical deposition (ECD), which is synonymous with the claimed electroplating.
    • Prior Art Mapping (Key Independent Claims):
      • Claim 4: Petitioner mapped Hsiung’s CVD TiN layer to the "first seed layer" and its PVD copper layer to the "second seed layer." Hsiung was alleged to explicitly teach that the second PVD copper seed layer (disclosed as up to 3000 Å thick) is thicker than the first CVD TiN seed layer (100-200 Å thick) over the field.
      • Claim 6 & 53: Hsiung's figures and the description of completely filling the openings after seed layer deposition were argued to inherently disclose that the two seed layers do not seal the opening, a key limitation of these claims.
      • Claim 10 & 26: Petitioner asserted that Hsiung’s disclosure of a "conformal" CVD TiN layer inherently means it provides the "continuous coverage" required by these claims. The subsequent thick PVD copper layer provides the required "low electrical resistance path" for uniform plating, a fact the ’052 patent itself acknowledges as common knowledge.
      • Claim 65: Petitioner contended that because Hsiung teaches using two fundamentally different deposition techniques (CVD and PVD), it inherently discloses using two different "sets of deposition parameters" as claimed.
    • Prior Art Mapping (Key Dependent Claims): Hsiung's disclosure of a PVD copper seed layer was argued to anticipate dependent claims requiring at least one seed layer to be copper. Its disclosure of depositing a barrier layer prior to the seed layers was argued to anticipate dependent claims requiring this step. Finally, Hsiung's specific thickness disclosures for its TiN layer (100-200 Å) and copper layer (>1000 Å) were argued to fall within the ranges recited in several dependent claims.

Ground 2: Obviousness Under §103 - Claims 7 and 11 are obvious over Hsiung.

  • Prior Art Relied Upon: Hsiung (Application # 2002/0045345)
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that even if not directly anticipated, the specific thickness limitations in dependent claims 7 and 11 would have been obvious over Hsiung's teachings. Claim 7 requires the first seed layer to be less than about 100 Å thick, while Hsiung discloses a range of "about 100 Å to 200 Å" for its first (TiN) seed layer. Petitioner asserted this overlapping range renders the claimed limitation obvious. Hsiung's disclosed range for the second seed layer (up to 3000 Å) directly meets the corresponding limitation in claim 7. Claim 11 contains similar thickness limitations dependent on claim 10.
    • Motivation to Combine: Not applicable as only one reference is used. However, Petitioner argued a person of ordinary skill in the art (POSITA) would have been motivated to slightly reduce the thickness of Hsiung's TiN layer to a sub-100 Å level.
    • Expectation of Success: A POSITA would have had a high expectation of success in creating a slightly thinner TiN layer (sub-100 Å) because the 100 Å value was not presented as a critical threshold in Hsiung, and achieving such a thickness was well within the known capabilities of standard CVD equipment at the time.

4. Key Claim Construction Positions

  • "Seed Layer": Petitioner argued that should the Board require construction, the term "seed layer" should be interpreted as "an electrically conductive layer that facilitates growth of a conductive material." This broad interpretation supports viewing both Hsiung's TiN layer and its copper layer as components of a seed layer structure.

5. Key Technical Contentions (Beyond Claim Construction)

  • "Conformal" implies "Continuous": A central technical assertion was that a layer described as "conformal," as Hsiung describes its CVD TiN layer, is inherently "continuous" for the purposes of claims 10 and 26. A discontinuity would be a severe form of non-conformality.
  • Different Processes Imply Different Parameters: Petitioner contended that using two distinct deposition processes (CVD and PVD), as taught by Hsiung, necessarily requires using different sets of deposition parameters (e.g., precursor gases and flow rates for CVD vs. target biasing for PVD). This was argued to satisfy the limitation of claim 65 without an explicit statement in the prior art.

6. Relief Requested

  • Petitioner requests institution of an inter partes review (IPR) and cancellation of claims 4-11, 13-18, 26, 27, 29-34, 53, 54, 56-58, and 65-68 of the ’052 patent as unpatentable.