PTAB

IPR2016-01683

AGIlTron Inc v. MemSCAp SA

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Thermally Actuated Microelectromechanical Systems Including Thermal Isolation Structures
  • Brief Description: The ’512 patent discloses a microelectromechanical (MEMS) device featuring a thermally actuated buckling beam connected to a substrate via one or more supports. To improve operational efficiency, the device incorporates a thermal isolation structure within the substrate to reduce heat conduction away from the beam during actuation.

3. Grounds for Unpatentability

Ground 1: Anticipation over Beatty - Claims 4 and 14 are anticipated by Beatty

  • Prior Art Relied Upon: Beatty (Patent 5,050,838).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Beatty, which was not considered during the original examination, discloses a MEMS microvalve that teaches every limitation of claims 4 and 14. Beatty’s device allegedly includes a microelectronic substrate (112), spaced apart supports (bonding material 132), and a beam (120) that expands and displaces upon the application of heat. Crucially, Petitioner asserted that Beatty discloses a solid thermal isolation structure, comprising silicon dioxide (210) and silicon nitride (220) layers, located in the substrate and adjacent to the supports, thereby meeting the key limitation added during prosecution of the ’512 patent.

Ground 2: Obviousness over Beatty and Tsai - Claims 1, 4, 10, and 14 are obvious over Beatty in view of Tsai

  • Prior Art Relied Upon: Beatty (Patent 5,050,838), Tsai (Patent 6,070,851).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Beatty teaches all elements of the challenged claims except for the specific "oxide filled trench in the substrate" limitation required by claims 1 and 10. This missing element, Petitioner argued, is supplied by Tsai. Tsai discloses a "thermally buckling micro structure" that incorporates a "heat isolating layer" (3) depicted as a trench within the device’s substrate (bridge pier 11). Tsai further teaches that this isolating layer can be a solid oxide structure formed by thermal oxidation.
    • Motivation to Combine: A POSITA would combine Beatty and Tsai because both references are in the identical field of thermally actuated MEMS microvalves and address the same need for thermal efficiency. Tsai explicitly teaches that including its thermal isolation trench improves device performance by reducing power consumption and increasing actuation force and precision. These stated benefits would have provided a strong motivation to incorporate Tsai's trench structure into Beatty's actuator design.
    • Expectation of Success: Petitioner argued it would be a simple engineering task to replace or augment the layered isolation structure in Beatty with the oxide-filled trench taught by Tsai. A POSITA would have a reasonable expectation of success in predictably achieving a greater degree of thermal isolation using well-understood fabrication techniques.

Ground 3: Anticipation over Klaassen - Claims 4 and 14 are anticipated by Klaassen

  • Prior Art Relied Upon: Klaassen ("Silicon Fusion Bonding and Deep Reactive Ion Etching," a 1995 conference paper).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner contended that Klaassen’s method for fabricating a bent-beam thermal actuator on a silicon-on-insulator (SOI) wafer meets all limitations of claims 4 and 14. Klaassen's actuator is formed from a top silicon layer that is bonded to a bottom "handle" wafer, with a 1µm thermal oxide layer between them. The supports and beam are etched from this top layer. Petitioner argued that this buried thermal oxide layer constitutes the claimed solid, thermally insulating structure in the substrate (the bonded wafer structure) and adjacent to the support (since the support sits on the oxide layer), thereby anticipating the claims.

  • Additional Grounds: Petitioner asserted additional obviousness challenges, including combinations of Beatty in view of Jang (Patent 5,741,740) and Klaassen in view of Bajor (Patent 4,771,016), Tsai, or Jang. These grounds followed a similar logic of combining a primary reference teaching a thermal actuator (Beatty or Klaassen) with a secondary reference teaching an alternative or improved method of creating thermal isolation structures (e.g., thicker oxide layers or different trench formations) to predictably enhance device efficiency. An additional ground alleged claims 4 and 14 are obvious over Wiszniewski (Patent 5,682,053) in view of Lisec (a 1994 publication).

4. Key Claim Construction Positions

  • "thermal isolation structure": Petitioner proposed a construction of "any structure that reduces thermal conduction compared to the absence of the said structure." This broad interpretation was central to arguing that the prior art's layered oxide/nitride structures and buried oxide layers met the claim limitation, even if they were not the trench structure shown in the patent's preferred embodiment.
  • "support": Petitioner proposed a construction of "a structure separate from the substrate that holds the beam spaced apart from the substrate." This construction was used to argue that the bonding materials and etched structures in the prior art, which sit on the substrate, qualified as the claimed "support."

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1, 4, 10, and 14 of Patent 6,262,512 as unpatentable.