PTAB

IPR2018-00452

Applied Materials 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 claimed methods involve depositing two sequential seed layers into openings (e.g., vias) to facilitate subsequent void-free filling by electroplating copper, addressing challenges with achieving continuous, conductive layers in high-aspect-ratio features.

3. Grounds for Unpatentability

Ground 1: Claims 4-11, 13-18, 26, 27, 29-34, 53, 54, 56-58, and 65-68 are obvious over Maydan in view of Rathore.

  • Prior Art Relied Upon: Maydan (Patent 6,372,633) and Rathore (Patent 6,069,068).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner asserted that Maydan taught the core method of all independent claims: a two-step seed layer process for filling vias. Maydan disclosed depositing a conformal copper "wetting layer" using chemical vapor deposition (CVD), which Petitioner equated to the claimed "first seed layer." Maydan then disclosed depositing a second metal layer, which could be a PVD seed layer, to facilitate subsequent electroplating. Petitioner argued this structure maps directly to the limitations of independent claims 4 and 6, which require a CVD first seed layer followed by a PVD second seed layer. For claims 10, 26, and 53, which require a "continuous" first seed layer, Petitioner argued that Maydan's conformal CVD layer inherently satisfied this limitation, as conformality was a known characteristic of CVD.

    • Motivation to Combine (for §103 grounds): Petitioner argued a person of ordinary skill in the art (POSITA) would combine Maydan and Rathore because both references addressed the same problem: improving copper interconnect formation. While Maydan disclosed the two-layer CVD/PVD process, it did not specify the relative thicknesses required by claims like claim 4 (wherein the second layer is thicker than the first). Rathore, however, provided specific guidance on this point. It warned that thicker CVD copper layers increase the risk of line contamination and taught preferable thickness ranges for both CVD (e.g., 100-700Å) and PVD (e.g., 600-2000Å) copper seed layers. A POSITA would combine Rathore's thickness optimization teachings with Maydan's process to achieve the predictable result of minimizing contamination while ensuring a sufficiently conductive PVD layer for uniform electroplating.

    • Expectation of Success (for §103 grounds): A POSITA would have a high expectation of success because combining the references involved applying known deposition techniques (CVD and PVD) and optimizing their well-understood parameters (thickness) to achieve predictable improvements in a known manufacturing process.

    • Key Aspects: A central element of Petitioner's argument was that the Patent Owner, during the re-examination of a parent patent (’707 patent), had previously characterized Maydan's "wetting layer 30" as a "seed layer," thereby strengthening the assertion that Maydan taught the first step of the claimed process. Furthermore, Petitioner noted that Maydan was never considered during the original prosecution of the ’052 patent.

  • Application to Other Key Claims:

    • Claims 10 and 26: These claims require the combined seed layers to provide a "low electrical resistance path." Petitioner argued that Rathore's disclosure of a PVD layer thickness of 600-2000Å, combined with admissions in the ’052 patent itself that a PVD layer of ~1000Å provides low resistance, taught this limitation. The combination of a thin, conformal CVD layer from Maydan and a thicker, low-resistance PVD layer from Rathore rendered the claims obvious.
    • Claim 65: This claim requires the two seed layers to be deposited using different "sets of deposition parameters." Petitioner asserted this was inherently taught by the combination, as using fundamentally different processes like CVD and PVD necessarily involves different parameters (e.g., precursor gas flow rates for CVD vs. sputtering target bias for PVD).
    • Dependent Claims: Petitioner argued that various dependent claims were obvious for reciting features also taught by the combination of Maydan and Rathore. This included limitations on layer material (copper, taught by both references), specific thickness ranges (taught by Rathore), and the presence of a prior barrier layer (taught by Maydan). For example, claim 7's requirement that the first layer be less than 100Å thick was obvious from Rathore's teaching to minimize CVD layer thickness to reduce contamination.

4. Key Claim Construction Positions

  • "Seed Layer": Petitioner argued this term should be given its broadest reasonable interpretation, which a POSITA would understand as "an electrically conductive layer that facilitates growth of a conductive material." This construction was critical to the invalidity argument, as it allowed Maydan's disclosed "wetting layer" to be properly considered a "seed layer" that meets the claim limitation. Petitioner supported this by citing the Patent Owner's own admissions during a related re-examination proceeding.

5. Relief Requested

  • Petitioner requests the institution of an inter partes review and cancellation of claims 4-11, 13-18, 26, 27, 29-34, 53, 54, 56-58, and 65-68 of Patent 7,199,052 as unpatentable under §103.