PTAB

IPR2017-01499

Hutchinson Technology Inc v. Nitto Denko Corp

Key Events

Petition

petition

Title: PRINTED CIRCUIT BOARD AND METHOD FOR MANUFACTURING SAME
Brief Description: The ’644 patent discloses a printed circuit board, such as those used in hard disk drive suspensions, with a specific wiring pattern configuration. The technology involves interleaving traces from first and second wiring patterns to reduce characteristic impedance at a low cost.

Prior Art Relied Upon: Contreras (Patent 8,154,827).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued that Contreras, which discloses an integrated lead suspension for a hard disk drive, teaches every limitation of claims 1-4. Contreras shows a printed circuit board with an insulating layer and first and second interleaved wiring patterns (traces 71-78) forming a signal pair. It discloses electrode pads (pads 54, 55, 56) connected to these patterns. Crucially, Contreras teaches a "first connecting layer" on the opposite surface of the insulator, in the form of an electrically isolated "island jumper" (island 90) made from the metal substrate. The petition mapped Contreras's "multiple-crossover coplanar connection" (MCC) to the claimed "intersection region," where wiring lines are divided and reconnected through vias (through-holes) to the island jumper. For dependent claim 2, Contreras’s island 90 is disclosed as part of a metal substrate layer but electrically separated by a gap, meeting the claim's requirements. For dependent claims 3 and 4, Contreras’s disclosure of a similar MCC at the opposite end of the flexure was argued to teach the claimed second intersection region and second connecting layer.

Prior Art Relied Upon: Contreras (Patent 8,154,827), Pro (Patent 8,379,349).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner asserted that claim 6, a method for manufacturing the circuit board of claim 1, is obvious. While Contreras discloses the claimed structure, it does not detail a manufacturing method. Pro, however, describes manufacturing an analogous integrated lead flexure with similar interleaved traces and jumper constructions. Pro explicitly teaches using known additive and subtractive processes, such as photolithography and etching, to form the flexure, traces, pads, connecting layer (conductive island), and through-holes.
- Motivation to Combine: A person of ordinary skill in the art (POSITA), seeking to manufacture the flexure disclosed in Contreras, would combine its structural teachings with the well-known fabrication methods for similar flexures taught by Pro. Both references describe flexures with a metal substrate, an insulating layer, interleaved wiring patterns, and jumper configurations for connecting trace ends. This structural similarity provided a clear reason to apply Pro’s manufacturing techniques to create the device of Contreras.
- Expectation of Success: Given the substantial structural similarities between the flexures in Contreras and Pro, a POSITA would have had a reasonable expectation of success in applying the manufacturing processes from Pro to produce the structure disclosed in Contreras.

Prior Art Relied Upon: Pro (Patent 8,379,349).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued that Pro, by itself, anticipates every element of claims 1-4 and 6. Pro discloses an integrated lead flexure with all structural features of independent claim 1: an insulating layer, interleaved transmission line arrays (first and second wiring patterns), terminal connector pads and head connector pads (electrode pads), and a jumper construction with an isolated conductive island (the connecting layer) on the other side of the insulator. Pro's jumper includes interconnects that function as the claimed through-holes. Because Pro teaches that its jumper construction can be located near the head connector pads and/or the terminal connector pads, it inherently discloses both a first and second intersection region. Furthermore, Pro explicitly describes the method for making its device, including using additive and subtractive processes like etching to form the jumper and through-holes, thereby teaching the manufacturing steps of method claim 6.

"connecting layer": Petitioner proposed that for the purposes of the inter partes review (IPR), this term should be construed as "a conductive layer that is part of the suspension body that allows electrical connection." This construction was based on the specification’s identification of "region RG1 of the suspension body 10" as an example of a connecting layer, which is itself described as an example of a metal layer. This construction is central to mapping the "island jumper" of Contreras and the "conductive island" of Pro to the claimed element.

Petitioner requested the institution of an IPR and the cancellation of claims 1-4 and 6 of the ’644 patent as unpatentable.