PTAB

IPR2014-00863

Fujitsu Semiconductor Ltd v. Zond LLC

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Plasma Generation for Sputtering Applications
  • Brief Description: The ’142 patent describes a method and apparatus for generating plasma for applications like sputtering. The invention involves first creating a low-density "weakly-ionized plasma" and then applying a high-power electrical pulse to rapidly increase its density into a "strongly-ionized plasma," a process intended to reduce the probability of electrical arcing.

3. Grounds for Unpatentability

Ground I: Claim 14 is obvious over Mozgrin in view of Lantsman

  • Prior Art Relied Upon: Mozgrin (a 1995 journal article on plasma discharge) and Lantsman (Patent 6,190,512).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Mozgrin teaches the core limitations of the challenged claims. Mozgrin describes a two-stage plasma generation process: a "pre-ionization" stage (region 1) corresponding to the claimed "weakly-ionized plasma," followed by a "high-current magnetron discharge" stage (region 2) created by applying a high-voltage pulse, which corresponds to the "strongly-ionized plasma." Petitioner asserted that Mozgrin explicitly teaches this pre-ionization stage reduces the probability of transitioning to an arc discharge, thus meeting the claim limitation of "reducing the probability of developing an electrical breakdown condition." Lantsman was introduced to teach the limitation of continuously supplying feed gas during the entire process, a detail not explicitly described in Mozgrin.
    • Motivation to Combine: Petitioner contended a POSITA would combine Mozgrin and Lantsman because both references address the same field of plasma sputtering and share the common goal of avoiding arcing. Lantsman's disclosure of continuous gas flow to maintain stable chamber pressure was presented as a conventional and well-known technique. A POSITA would have found it obvious to apply this standard gas management technique from Lantsman to the plasma generation system of Mozgrin to ensure stable and predictable operation.
    • Expectation of Success: Success was expected because the combination involved applying a standard, known technique (continuous gas flow) to a known system (a sputtering apparatus) to achieve a predictable result (stable pressure).

Ground II: Claims 13 and 14 are obvious over Wang in view of Lantsman

  • Prior Art Relied Upon: Wang (Patent 6,413,382) and Lantsman (Patent 6,190,512).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Wang, which describes a commercial-grade sputtering system, teaches a process nearly identical to that claimed. Wang discloses using a low-level "background power" to maintain a plasma between pulses, which Petitioner mapped to the "weakly-ionized plasma." It then applies a high "peak power" pulse to increase plasma density for sputtering, corresponding to the "strongly-ionized plasma." Wang explicitly teaches that maintaining this background plasma reduces arcing during ignition. As in Ground I, Lantsman was cited for its teaching of supplying feed gas throughout the entire plasma process. Dependent claim 13, requiring a "quasi-static electric field," was allegedly met because Wang's pulse width (at least 50 µs) is significantly longer than the calculated electron collision time in the operating environment.
    • Motivation to Combine: The motivation was similar to Ground I. Both Wang and Lantsman are directed to plasma sputtering, use dual power supplies (one for pre-ionization/maintenance, one for deposition), and aim to avoid arcing. A POSITA would combine Lantsman’s conventional gas flow method with Wang’s sputtering system to achieve the well-known benefit of stable process pressure.
    • Expectation of Success: Petitioner argued success would be highly predictable, as it constituted the implementation of a basic process control element into a known system.

Ground III: Claims 2 and 11 are obvious over Mozgrin, Lantsman, and Kudryavtsev

  • Prior Art Relied Upon: Mozgrin (a 1995 journal article), Lantsman (Patent 6,190,512), and Kudryavtsev (a 1983 technical paper on ionization relaxation).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground built upon the combination of Mozgrin and Lantsman from Ground I to address the additional limitations of claims 2 and 11. These claims recite the specific mechanism for creating the strongly-ionized plasma: exciting atoms in the weakly-ionized plasma and then using secondary electrons to ionize those excited atoms (i.e., multi-step ionization). Petitioner argued that Kudryavtsev provides an explicit technical explanation of this "stepwise" ionization process, describing how an initial electric field creates a population of excited atoms, which then leads to an "explosive increase" in electron density.
    • Motivation to Combine: Petitioner asserted a powerful motivation to combine Mozgrin and Kudryavtsev because Mozgrin explicitly cites Kudryavtsev, stating its teachings on ionization relaxation were taken "into account" when designing the experiments described in Mozgrin. Therefore, a POSITA reading Mozgrin would have been directly led to Kudryavtsev to understand the underlying physics of the rapid plasma density increase observed.
    • Expectation of Success: The expectation of success was argued to be high, as the combination merely involved articulating the known physical principles (from Kudryavtsev) that were already being utilized and referenced by the primary prior art (Mozgrin).

  • Additional Grounds: Petitioner asserted additional obviousness grounds, including challenges to claims 2 and 11 over Wang, Lantsman, and Kudryavtsev, and challenges to claims 13 and 16 over combinations involving Mozgrin Thesis, a more detailed version of the Mozgrin article. These grounds relied on similar mapping and motivation arguments.

4. Key Claim Construction Positions

  • Petitioner argued for the following constructions based on the specification and the patent owner’s statements in a related European prosecution:
    • "weakly-ionized plasma": Proposed construction is "a lower density plasma."
    • "strongly-ionized plasma": Proposed construction is "a higher density plasma."
  • These constructions were central to Petitioner's strategy of mapping the prior art's descriptions of "pre-ionization" or "background" plasma to the "weakly-ionized" limitation, and "high-current discharge" or "peak power" plasma to the "strongly-ionized" limitation.

5. Relief Requested

  • Petitioner requested the institution of an inter partes review and cancellation of claims 2, 11, 13, 14, and 16 of the ’142 patent as unpatentable under 35 U.S.C. §103.