PTAB

IPR2018-00775

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 ’226 patent describes a method for fabricating metallic interconnects on a semiconductor substrate. The method involves depositing multiple distinct seed layers—including at least one "substantially conformal" layer and one "substantially non-conformal" layer—to improve the subsequent filling of vias and trenches with electroplated metal.

3. Grounds for Unpatentability

Ground 1: Obviousness of Claims 71-73, 76, 79, 80 over Maydan in view of Brown

  • Prior Art Relied Upon: Maydan (Patent 6,372,633) and Brown (Patent 6,187,670).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that independent claim 71, which recites depositing three or more seed layers using at least one substantially conformal technique and one substantially non-conformal technique, is rendered obvious by the combination. Maydan was asserted to disclose a process for forming copper interconnects that includes depositing a conformal Chemical Vapor Deposition (CVD) wetting layer followed by combinations of CVD and Physical Vapor Deposition (PVD) seed layers, resulting in at least three seed layers. Petitioner contended that while Maydan does not explicitly describe the PVD layers as "substantially non-conformal," Brown teaches that traditional PVD sputtering, a known non-conformal technique, results in a sidewall-to-field thickness ratio of 5% or less, which falls squarely within the ’226 patent's explicit definition of "substantially non-conformal" (less than 25%). Maydan's CVD layer was argued to be inherently "substantially conformal" (25-100% coverage), a fact acknowledged in the art.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine Maydan and Brown because both references address the same problem of improving copper interconnects for electroplating. A POSITA implementing Maydan's process would have naturally turned to a well-known, simple PVD process like the one described in Brown to form the non-conformal layers, as it was a standard technique for that purpose.
    • Expectation of Success: A POSITA would have had a high expectation of success because the combination involves applying a standard, predictable PVD technique (from Brown) to a known multi-layer interconnect process (from Maydan) to achieve the desired seed layer structure.

Ground 2: Obviousness of Claims 14, 15, 64, 65 over Maydan in view of Rathore, Brown, and Fukui

  • Prior Art Relied Upon: Maydan (Patent 6,372,633), Rathore (Patent 6,069,068), Brown (Patent 6,187,670), and Fukui (Patent 5,755,938).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground challenged independent claim 64 and dependent claims requiring that the seed layers be deposited in a single chamber. Petitioner argued that the base combination of Maydan and Brown teaches the layered structure, as in Ground 1. Rathore was introduced to teach the specific relative thicknesses of the layers, disclosing that a thinner CVD layer could be combined with a thicker PVD layer to avoid defects and contamination. This addresses the limitation that the non-conformal layer is thicker than the conformal layer. Fukui was added to teach performing both CVD and PVD processes sequentially in a single deposition chamber, directly mapping to the "single chamber" limitation in claims 14 and 64.
    • Motivation to Combine: A POSITA would combine these references to optimize the process taught by Maydan. Rathore would be consulted to solve known problems of void formation and contamination by specifying layer thicknesses. Fukui would be incorporated for its explicit teaching of a single-chamber CVD/PVD apparatus, which provides clear advantages in efficiency, cost, and reduced footprint, motivating a POSITA to integrate its design.
    • Expectation of Success: Success was predictable, as it involved combining known process enhancements (Rathore's thickness ratios, Fukui's single-chamber design) with a known foundational method (Maydan's layering) to create an improved, more efficient manufacturing process.

Ground 3: Obviousness of Claim 77 over Maydan in view of Brown and Sherman

  • Prior Art Relied Upon: Maydan (Patent 6,372,633), Brown (Patent 6,187,670), and Sherman (Patent 6,342,277).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground targeted claim 77, which requires the substantially conformal layer to be deposited via Atomic Layer Deposition (ALD). Petitioner asserted that Maydan and Brown establish the basic two-layer structure. Sherman was introduced for its teaching of using ALD to deposit "perfectly conformal" and pure copper films at low temperatures.
    • Motivation to Combine: Petitioner argued a POSITA, seeking to form the conformal layer in Maydan's process, would have been motivated to use Sherman’s ALD technique. The motivation stems from ALD's known ability to produce superior conformal layers, which directly addresses the goal of Maydan's process, while also offering benefits like higher purity and lower cost.

  • Additional Grounds: Petitioner asserted additional obviousness challenges against other dependent claims by adding single references to the core combination of Maydan, Rathore, Brown, and Fukui. These included: Teer (Patent 5,556,519) to teach an ion plating deposition chamber (claims 16, 66); Fu (Patent 6,692,617) to teach a Self-Ionized Plasma (SIP) sputtering chamber (claims 18, 68); Hong (Patent 6,376,807) to teach an Ionized Metal Plasma (IMP) sputtering chamber (claims 19, 69); and Ikegami (Patent 6,200,735) to teach forming openings with a width less than 0.13µm (claims 20, 70).

4. Key Claim Construction Positions

  • Petitioner argued that several key terms should be construed based on explicit definitions provided by the patent owner in the specification, as the inventor acted as his own lexicographer.
  • "A substantially conformal seed layer": Proposed construction is "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": Proposed construction is "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." Petitioner asserted these definitions are critical because its obviousness arguments rely on prior art techniques (like PVD) inherently producing layers that meet the patent's specific quantitative definition for "non-conformal."

5. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial under §314(a) or §325(d) was not warranted. Petitioner acknowledged having filed two prior IPR petitions (IPR2018-00445 and IPR2018-00446) against the ’226 patent. However, it contended that the present petition was not abusive because it challenges an entirely different set of claims (e.g., 14-16, 64-66, 71-73) than those challenged in the earlier petitions (1, 21-24, 27-29).

6. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 14-16, 18-20, 64-66, 68-70, 71-73, 76-77, 79, and 80 of the ’226 patent as unpatentable.