PTAB

IPR2018-00618

SPTS Technologies Ltd v. Plasma Therm LLC

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Key Events
Petition

1. Case Identification

2. Patent Overview

  • Title: Method of Forming Individual Device Chips from a Semiconductor Wafer
  • Brief Description: The ’332 discloses a method for plasma dicing a semiconductor wafer to form individual device chips. The method involves handling a workpiece, comprising a substrate mounted on a support film and frame, using a transfer arm and a lifting mechanism within a plasma processing chamber.

3. Grounds for Unpatentability

Ground 1: Claims 1-2 are obvious over Singh in view of Yamamoto or Kobayashi.

  • Prior Art Relied Upon: Singh (Application # 2012/0322239), Yamamoto (Patent 7,896,047), and Kobayashi (Application # 2005/0229370).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Singh discloses nearly every element of the challenged claims. Specifically, Singh taught a method for plasma dicing a workpiece (a substrate on a support film and frame) within a process chamber. Crucially, Singh also disclosed the workpiece handling system, including a transfer arm that supports the workpiece without contacting the substrate, and a lifting mechanism (a capture ring) that engages only the frame of the workpiece to lift it from the transfer arm. Petitioner contended that the only element of claim 1 not expressly taught by Singh is a workpiece frame having an "exposed lower surface." This limitation, however, was taught by both Yamamoto and Kobayashi, which disclosed conventional, automated techniques for preparing a workpiece by joining a support film to a dicing frame in a way that leaves an outer portion of the frame's lower surface exposed. Dependent claim 2, reciting an "alignment fixture," was also allegedly taught by Singh's use of support edges on its transfer arm to align the workpiece.
    • Motivation to Combine: Petitioner asserted that a person of ordinary skill in the art (POSITA) would have been motivated to use the automated workpiece preparation methods of Yamamoto or Kobayashi to create the workpiece for use in Singh's plasma dicing process. The motivation stemmed from the well-known benefits of such automated front-end processes, including improved efficiency, cost savings, repeatability, and accuracy. A POSITA would have viewed this as simply combining a known method of making a workpiece with a known method of processing that workpiece.
    • Expectation of Success: Petitioner argued there would be a high expectation of success because the combination involved the straightforward application of a conventional workpiece (from Yamamoto or Kobayashi) in a compatible plasma dicing and handling system (from Singh). Nothing in Singh would have precluded the use of a workpiece with an exposed lower frame surface.

4. Key Claim Construction Positions

  • "lifting mechanism": Petitioner proposed this term be construed broadly as "any device configured to allow a work piece to be placed thereon and operative to lift the work piece." This broad construction was important for mapping Singh's capture ring and pin system to the claimed limitation, as the ’332 patent provided little structural detail for the term.
  • "lower surface" of the frame: Petitioner proposed construing this term as "any surface of the frame facing downwardly when the work piece is supported for transfer and/or processing." This construction was central to both the priority date arguments and the mapping of the Yamamoto and Kobayashi references, which showed downward-facing frame surfaces that were purposefully left exposed.
  • "a portion of the work piece overlapped by the frame": Petitioner proposed this term means "the frame itself, or a portion of one side of the support film that is in contact with the frame on the opposite side of that same portion of the support film." This construction was necessary to argue that Singh’s lifting mechanism, which contacted the workpiece frame, met this claim limitation.

5. Key Technical Contentions (Beyond Claim Construction)

  • Denial of Priority Date: A central contention of the petition was that the ’332 patent was not entitled to the earlier filing dates of its parent or provisional applications, making the cited references valid prior art. Petitioner presented two primary arguments for this position:
    • First, Petitioner argued the Patent Owner procedurally waived any claim to the provisional application’s priority date by failing to timely and correctly identify the priority claim in an Application Data Sheet (ADS) during prosecution, as required by PTO rules.
    • Second, Petitioner argued that the earlier-filed applications lacked an adequate written description for the key limitation of "an exposed lower surface" of the frame. The petition contended that the priority documents not only failed to describe this feature but actively taught away from it, emphasizing the need to cover and protect the frame from plasma exposure, contrary to the claim language.

6. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1-2 of the ’332 patent as unpatentable under 35 U.S.C. §103.