PTAB

IPR2018-00448

Applied Materials Inc v. Uri Cohen

Log In
Key Events
Petition
petition

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 aims to achieve void-free electrochemical filling of narrow, high-aspect-ratio openings by using a first "substantially conformal seed layer" followed by a second, thicker "substantially non-conformal seed layer."

3. Grounds for Unpatentability

Ground 1: Claims 1-4, 14, 16, 26, 28, 29, 36, 37, 40, and 42-44 are obvious over Hsiung.

  • Prior Art Relied Upon: Hsiung (Application # 2002/0045345).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Hsiung discloses all limitations of independent claim 1. Hsiung teaches a process to enhance copper damascene fabrication using a dual-layer seed structure to improve electroplating. Specifically, Hsiung discloses depositing a first Titanium Nitride (TiN) layer via chemical vapor deposition (CVD) over a barrier layer, followed by a second copper seed layer via physical vapor deposition (PVD). Petitioner contended that Hsiung's CVD TiN layer functions as the claimed "substantially conformal seed layer" (defined as having 25-100% sidewall-to-field thickness ratio), as CVD was known to produce highly conformal films with near 100% step coverage. Hsiung’s PVD copper layer, described as having "discontinuities," functions as the "substantially non-conformal seed layer" (defined as <25% ratio), as PVD was known to produce poor sidewall coverage, resulting in a ratio well within this range (often near 0% at points). Hsiung also discloses that its second (PVD) seed layer is thicker than its first (CVD) seed layer and is subsequently covered by an electroplated copper layer, thus meeting all elements of claim 1. Arguments for dependent claims followed from Hsiung's disclosure of specific materials (e.g., Ta/TaN barrier layer), deposition methods (CVD for first layer, PVD for second), and subsequent processing steps (chemical mechanical polishing).
    • Motivation to Combine (for §103 grounds): Not applicable (single reference ground).
    • Expectation of Success (for §103 grounds): Not applicable (single reference ground).

Ground 2: Claims 15 and 41 are 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:
    • Prior Art Mapping: This ground addressed dependent claims 15 and 41, which further require that the barrier layer is deposited by a CVD technique. While Hsiung teaches a barrier layer, it focuses on PVD deposition and explicitly recognizes its shortcomings, such as "poor sidewall coverage." Brown addresses this exact problem by teaching the use of various deposition techniques for a barrier layer, specifically including CVD as a method to achieve a more robust and conformal layer.
    • Motivation to Combine (for §103 grounds): Petitioner argued a person of ordinary skill in the art (POSITA), facing the "poor sidewall coverage" problem identified in Hsiung's PVD barrier layer, would be motivated to improve the process. A POSITA would have looked to known, predictable solutions and found Brown, which teaches using CVD to form a barrier layer precisely to overcome such issues. The combination represented the application of a known technique (CVD for barrier layers from Brown) to a known system (the dual seed layer structure of Hsiung) to solve a known problem.
    • Expectation of Success (for §103 grounds): Since CVD was a well-known and predictable method for forming conformal films at the time, a POSITA would have had a high expectation of success in substituting the PVD barrier layer process in Hsiung with a CVD process taught by Brown to improve performance.

4. Key Claim Construction Positions

  • "Substantially Conformal Seed Layer" / "Substantially Non-conformal Seed Layer": Petitioner argued these terms should be construed according to their explicit definitions provided in the ’668 patent specification. A "substantially conformal seed layer" is defined as "a layer whose thickness on the sidewalls of an opening (at about mid-depth) is about 25-100% of its thickness on the field." A "substantially non-conformal seed layer" is defined as a layer with a corresponding ratio of "less than about 25%." Petitioner asserted these definitions were created by the inventor for the ’668 patent and were not standard in the field.

5. Key Technical Contentions (Beyond Claim Construction)

  • Priority Date Challenge: A central contention was that the ’668 patent is not entitled to the priority date of its earlier-filed parent applications. Petitioner argued that the parent applications failed to provide adequate written description support under 35 U.S.C. §112 for the broad numerical ranges (25-100% and <25%) that define the key claim terms. Because these specific, broad definitions were first introduced in the application for the ’668 patent itself, Petitioner contended its effective priority date is its filing date of December 4, 2000. This later priority date is critical, as it establishes Hsiung (filed 1999) and Brown (filed 1998) as valid prior art under 35 U.S.C. §102.

6. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-4, 14-16, 26, 28, 29, 36, 37, and 40-44 of Patent 6,518,668 as unpatentable.