PTAB

IPR2017-01441

Composite Materials Technology Inc v. Greatbatch Ltd

Log In
Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Method of Making an Anode for a High Voltage Capacitor
  • Brief Description: The ’075 patent discloses a method for producing anodes for high-voltage implantable electrolytic capacitors. The process involves providing tantalum fibers with specific dimensions, agglomerating the fibers into a powder, pressing the powder into a pellet, sintering the pellet, and anodizing it at a high formation voltage to create a dielectric oxide layer.

3. Grounds for Unpatentability

Ground 1: Obviousness over Fife and Stephenson - Claims 1-11 and 13-18 are obvious over Fife in view of Stephenson.

  • Prior Art Relied Upon: Fife (Patent 5,217,526) and Stephenson (Patent 6,231,993).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Fife teaches every step recited in independent claim 1 for producing a tantalum anode except for the final anodizing voltage. Fife discloses providing tantalum fibers of overlapping dimensions, forming them into a primary powder, agglomerating the powder, pressing it into a pellet, and sintering the pellet. However, Fife teaches anodizing to a formation voltage of only 100V. Petitioner asserted that Stephenson, which is Applicant Admitted Prior Art (AAPA), remedies this deficiency by explicitly teaching the anodizing of sintered tantalum pellets at formation voltages of 380V and 405V, thus meeting the ’075 patent’s limitation of “at least 300 V.” Petitioner further mapped limitations of the dependent claims to disclosures within Fife, such as fiber aspect ratios, powder densities, and sintering temperatures.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine Fife and Stephenson because both references are directed to the same field of art: the production of tantalum capacitors. Petitioner noted that both Fife and Stephenson are cited as AAPA in the specification of the ’075 patent, confirming their relevance and indicating that a POSITA would have been aware of both. The motivation was to apply a known, effective high-voltage anodizing process from Stephenson to the anode structure created by Fife's method to achieve a high-voltage capacitor.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success in applying Stephenson’s higher anodizing voltage to the sintered pellet of Fife. The combination represented a simple substitution of one known process parameter (anodizing voltage) for another to achieve a predictable result, as Stephenson’s technique was designed for the same type of tantalum material.

Ground 2: Obviousness over Fife, Stephenson, and Liu - Claim 12 is obvious over Fife in view of Stephenson and Liu.

  • Prior Art Relied Upon: Fife (Patent 5,217,526), Stephenson (Patent 6,231,993), and Liu (Patent 6,965,510).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground built upon the combination in Ground 1 to address dependent claim 12, which adds the limitation of sintering the tantalum pellet in a vacuum. Petitioner argued that the base method from Fife and Stephenson lacked an explicit disclosure of vacuum sintering. Fife taught sintering as a "conventional practice" without specifying the atmosphere. To supply this element, Petitioner pointed to Liu, also AAPA in the ’075 patent, which explicitly describes an "exemplary sintering protocol" for tantalum anodes that includes sintering at a vacuum of 10⁻⁴ to 10⁻⁶ Torr.
    • Motivation to Combine: A POSITA, seeking to implement the "conventional" sintering step taught by Fife, would be motivated to consult other references in the field for specific, optimized protocols. Liu provided a known and advantageous method for sintering tantalum—performing it under a vacuum to improve purity and performance. The common subject matter and status of all three references as AAPA provided a clear motivation to combine their teachings to arrive at the claimed method.

Ground 3: Obviousness over Wong and Stephenson - Claims 1-11 and 13-18 are obvious over Wong in view of Stephenson.

  • Prior Art Relied Upon: Wong (Patent 5,896,196) and Stephenson (Patent 6,231,993).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner contended that the process for forming tantalum filaments detailed in the ’075 patent specification is "essentially verbatim copied" from Wong. Wong was alleged to teach the entire process of forming tantalum rods, embedding them in a copper matrix, extruding and drawing them into a composite wire, cutting the wire, and leaching out the copper to yield fine tantalum fibers. This process, Petitioner argued, inherently results in fibers meeting the dimensional limitations of claim 1. As with Fife in Ground 1, the Wong method was combined with Stephenson’s teaching of high-voltage anodizing (≥ 300V) to meet all limitations of the independent claim.
    • Motivation to Combine: The motivation to combine Wong and Stephenson was identical to that for combining Fife and Stephenson. A POSITA would apply the known high-voltage anodizing step from Stephenson to the tantalum anodes produced by the well-known method disclosed in Wong to create a high-performance capacitor.
    • Key Aspects: Petitioner emphasized that the textual description of the fiber manufacturing process and several figures in the ’075 patent were identical to those in Wong. The core of this argument was that products formed by identical processes cannot have patentably distinct properties, rendering the claims obvious.

  • Additional Grounds: Petitioner asserted an additional obviousness challenge against claim 12 based on the combination of Wong, Stephenson, and Liu, relying on the same rationale presented in Ground 2 but substituting Wong for Fife as the primary reference.

4. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-18 of Patent 9,312,075 as unpatentable under 35 U.S.C. §103.