PTAB

IPR2018-01597

Toshiba Memory Corp v. Anza Technology Inc

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1. Case Identification

2. Patent Overview

  • Title: Dissipative Ceramic Bonding Tip
  • Brief Description: The ’479 patent discloses a bonding tool tip for use in semiconductor manufacturing made from a dissipative ceramic material. The material is designed to have a specific electrical resistance range, high enough to prevent damaging current surges but low enough to safely dissipate electrostatic charge, thereby avoiding electrostatic discharge (ESD) damage to sensitive electronic components during the bonding process.

3. Grounds for Unpatentability

Ground 1: Anticipation - Claims 37 and 39 are anticipated by Shinji

  • Prior Art Relied Upon: Shinji (Patent 6,274,524)
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Shinji discloses every element of claims 37 and 39. Shinji teaches a wire bonding tool made from a zirconia sintering body mixed with conductive agents (e.g., iron oxide) to control its electrical properties. Petitioner asserted that the resulting material has a volume resistivity between 10⁵ and 10⁹ ohm·cm, which falls squarely within the "dissipative material" range recited in claim 37, under Petitioner’s proposed construction. For claim 39, Petitioner argued Shinji’s use of a zirconia-based material, known for its high strength and hardness, inherently meets the claim’s requirements for stiffness and abrasiveness, noting that the disclosed materials have a Vickers hardness corresponding to 68-72 HRC, exceeding the ’479 patent’s preferred hardness of 32 HRC.

Ground 2: Obviousness - Claims 37 and 39 are obvious over Shinji in view of Linn

  • Prior Art Relied Upon: Shinji (Patent 6,274,524) and Linn (Patent 5,816,472)
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner contended that even if Shinji alone does not teach a specific resistance value (as opposed to resistivity), the combination with Linn renders the claims obvious. Shinji taught the dissipative material composition, while Linn, which was directed to a commercial alumina-based bonding tool, provided specific, conventional dimensions for such a tool. Petitioner calculated that a bonding tool made with Shinji's material and Linn's dimensions would exhibit an end-to-end resistance of 1.56x10⁷ to 1.56x10¹¹ ohms, a range that falls within the ’479 patent’s preferred resistance of 10⁵ to 10¹² ohms.
    • Motivation to Combine: A POSITA would combine Linn’s known, commercially available bonding tool dimensions with Shinji’s improved dissipative material to create a tool compatible with existing bonding machines. Using standard dimensions would be a simple and predictable design choice to ensure interoperability.
    • Expectation of Success: A POSITA would have a reasonable expectation of success because combining a known material with standard tool dimensions involved applying well-understood engineering principles with predictable results.

Ground 3: Obviousness - Claims 37 and 39 are obvious over Alfaro in view of Shikata

  • Prior Art Relied Upon: Alfaro (Patent 4,974,767) and Shikata (Patent 5,830,819)

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued that Alfaro taught a conventional wire bonding capillary tool made from alumina, a ceramic material. However, Alfaro did not specify the alumina’s electrical properties. Shikata addressed the known problem of ESD in semiconductor manufacturing tools by teaching an aluminous sintered product with a volume resistivity controlled to be "between that of an insulator and that of an electric conductor" to prevent static charge issues. This directly corresponds to the "dissipative material" required by claim 37. For claim 39, both Alfaro and Shikata taught using alumina, a material known to possess the high stiffness and hardness required by the claim.
    • Motivation to Combine: A POSITA would combine Shikata's teachings with Alfaro's tool because Shikata identified a specific problem inherent in alumina-based tools like Alfaro's (i.e., potential for ESD) and provided a clear solution: modifying the alumina composition to achieve dissipative properties. This modification was presented as a direct improvement for such tools.
    • Expectation of Success: The combination was a predictable solution to a known problem, with Shikata providing explicit instructions on how to modify alumina to achieve the desired dissipative characteristics without compromising its mechanical properties.

  • Additional Grounds: Petitioner asserted additional obviousness challenges, including that the claims are obvious over Popp (German Patent DE 3743630) alone, and over Popp in view of Schneider (Patent 5,610,442). These grounds relied on Popp’s teaching of wear-resistant, dissipative ceramic materials for handling sensitive components.

4. Key Claim Construction Positions

Petitioner dedicated significant argument to claim construction, contending that several key terms are indefinite. For the purpose of the IPR, Petitioner analyzed unpatentability under its own and the Patent Owner's proposed constructions.

  • "bonding tip" (claim 37): Petitioner argued this term is indefinite because the ’479 patent used it inconsistently to refer to both the entire bonding tool and a small end portion of the tool, with no clear delineation.
  • "dissipative material" (claims 37 & 39): Petitioner proposed this term should be construed as a material with an electrical resistivity between 10⁵ and 10¹² ohms (per square), based on industry standards at the time and the patent's disclosure. Petitioner argued Patent Owner’s qualitative definition ("between that of insulative and conductive materials") was insufficient and ambiguous.
  • "a resistance low enough to prevent a discharge ... and high enough to avoid current flow large enough to damage said device" (claim 37): Petitioner argued this functional language is indefinite because the patent provided no guidance on how to determine what is "low enough" or "high enough" for any given device. Petitioner also contended the phrase is inoperable, as the "low enough" limitation (preventing any discharge) and the "high enough" limitation (allowing some current flow) are contradictory.

5. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 37 and 39 of the ’479 patent as unpatentable.