PTAB

IPR2017-01625

Hutchinson Technology Inc v. Nitto Denko Corp

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: PRINTED CIRCUIT BOARD AND METHOD FOR MANUFACTURING SAME
  • Brief Description: The ’644 patent discloses a printed circuit board for hard disk drive suspensions and its manufacturing method. The invention aims to reduce the characteristic impedance of signal lines by using an interleaved wiring pattern where traces of a first wiring pattern are located between traces of a second wiring pattern.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claims 1-2 and 6 by Rice

  • Prior Art Relied Upon: Rice (Patent 8,169,746).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Rice, which discloses an integrated lead head suspension flexure, teaches every limitation of independent claims 1 and 6 under 35 U.S.C. §102. Rice allegedly discloses an insulating layer supporting two pairs of interleaved wiring patterns and their associated electrode pads. Petitioner mapped Rice's "spring metal island 82" to the claimed "first connecting layer" located on the opposite side of the insulator, and Rice's conductive vias 84 to the claimed through-holes that electrically connect the wiring patterns to the connecting layer. For dependent claim 2, Petitioner asserted Rice's spring metal island is disclosed as being part of, but electrically isolated from, the main spring metal layer, thus anticipating the claim.

Ground 2: Obviousness of Claims 3-4 over Rice

  • Prior Art Relied Upon: Rice (Patent 8,169,746).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued claims 3-4 are obvious over Rice. Dependent claim 3 adds a "second connecting layer." While Rice discloses only one such layer (the spring metal island in Fig. 4), it also discloses a different crossover structure using a conductive jumper (Fig. 2). Petitioner contended it would have been obvious to modify Rice by using the superior Fig. 4 island structure for both of the required crossover regions, thereby providing a second connecting layer and meeting the limitations of claims 3 and 4.
    • Motivation to Modify: A POSITA would modify Rice to achieve design simplicity and improve manufacturability. Using a single, consistent crossover design (the island structure) would be simpler than using two different types. Furthermore, the island structure avoids additional processing steps associated with the jumper and advantageously keeps all electrode connections on a single plane.
    • Expectation of Success: A POSITA would have a high expectation of success, as the island-based structure from Rice's Fig. 4 was known to perform the exact same electrical crossover function as the jumper-based structure in Fig. 2 within the same device.

Ground 3: Obviousness of Claims 1-4 and 6 over Young in view of Yang

  • Prior Art Relied Upon: Young (Patent 5,717,547) and Yang (Patent 7,342,750).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that claims 1-4 and 6 are obvious over the combination of Young and Yang. Young was argued to teach the basic printed circuit board with interleaved wiring patterns on an insulating layer. However, Young does not teach the specific crossover structure recited in the claims, which requires a connecting layer on the opposite side of the insulator connected by through-holes. Yang was introduced to supply this missing element, as it explicitly teaches a crossover feature for hard disk drive suspensions that uses a conductive island on the opposite surface of an insulator, connected via through-holes, to allow traces to cross.
    • Motivation to Combine: A POSITA would combine Young and Yang to create a complete, functional device. Young expressly requires "bridge interconnect paths" for its traces to cross over but fails to specify their structure. A POSITA, faced with this design problem, would look to known solutions in the hard disk suspension art. Yang provided a known, elegant, and effective solution to this exact problem. The motivation was therefore to implement a functional crossover for Young's trace layout using the known technique taught by Yang.
    • Expectation of Success: The combination was presented as having a high likelihood of success because Yang's crossover technology was designed for the same technical environment and solved the precise problem left open by Young. The combination represented a straightforward application of a known technique to solve a known problem.

4. Key Claim Construction Positions

  • Term: "connecting layer" (recited in claims 1-4 and 6).
  • Petitioner's Proposed Construction: Petitioner proposed construing the term as "a conductive layer that is part of the suspension body that allows electrical connection."
  • Significance: This construction was asserted to be consistent with the ’644 patent’s specification. It was critical to Petitioner's invalidity arguments, as it supported mapping the "spring metal island 82" of Rice and the "conductive island area 450" of Yang—both of which are conductive islands formed from a larger support structure—to this specific claim limitation.

5. Relief Requested

  • Petitioner requested the institution of an inter partes review for all asserted grounds and the cancellation of claims 1-4 and 6 of the ’644 patent as unpatentable.