Nitto Denko Corp. v. Hutchinson Technology Incorporated

1. Case Identification

• Case #: IPR2018-01042
• Patent #: 7,781,679
• Filed: May 21, 2018
• Petitioner(s): Nitto Denko Corp.
• Patent Owner(s): Hutchinson Technology Inc.
• Challenged Claims: 1-7, 15-16, and 18-20

2. Patent Overview

• Title: Disk Drive Suspension Via Formation Using a Tie Layer and Product
• Brief Description: The ’679 patent discloses a hard drive suspension interconnect that provides an electrical ground connection. The ground is formed by filling an aperture in an insulating polymer layer with multiple sputtered and electroplated metal layers, avoiding the use of high-resistance conductive glue that was allegedly common in the prior art.

3. Grounds for Unpatentability

Ground 1: Claims 1-5 are obvious over Swanson

• Prior Art Relied Upon: Swanson (Patent 7,142,395).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Swanson discloses a hard drive suspension with a stainless steel layer, a polyimide dielectric layer, and an aperture with sloped walls, as required by claim 1. Swanson’s Figure 14 shows a ground structure formed by filling this aperture with layers of plated metal (gold-nickel-gold). While Swanson's primary example does not use the claimed chromium and copper layers, it explicitly teaches that a chromium seed layer can be applied to the stainless steel and that copper is an acceptable and interchangeable material for the conductive layers.
  • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine the teachings within Swanson itself. The reference explicitly stated that its grounding feature (Fig. 14) can be combined with other disclosed embodiments, such as those using a chromium seed layer, and that materials like copper can be substituted for gold and nickel.
  • Expectation of Success: Because Swanson itself teaches the interchangeability of these well-known metals and manufacturing steps for the same purpose, a POSITA would have had a high expectation of success in making these simple substitutions to arrive at the claimed invention.

Ground 2: Claims 1-3, 5-7, 15-16, and 18-20 are obvious over Aonuma combined with Naito

• Prior Art Relied Upon: Aonuma (Application # 2005/0282088) and Naito (Application # 2005/0062160).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Aonuma discloses a ground structure that is nearly identical to the invention, teaching the exact sequence of claimed layers: a sputtered chromium layer on stainless steel, followed by a sputtered copper layer, and an electroplated copper layer to fill an aperture. Aonuma, however, does not explicitly disclose the claimed wall slope ranges for its aperture. Naito was introduced to supply this teaching, as it discloses forming via holes with wall angles in the 40° to 70° range, which overlaps with the ’679 patent's requirements.
  • Motivation to Combine: A POSITA, seeking to optimize the fabrication process in Aonuma, would combine its teachings with Naito. Naito explicitly teaches that using its sloped wall angles improves the evenness and thickness of sputtered and plated metal layers within the via, preventing defects. A POSITA would be motivated to apply this known technique to Aonuma’s similar structure to achieve the same benefit.
  • Expectation of Success: The combination was portrayed as predictable, as both references relate to forming metalized vias in circuit boards using similar materials and processes (sputtering, electroplating, and laser drilling for aperture formation).

Ground 3: Claims 1-3, 5-7, 15-16, and 18-20 are obvious over Fu combined with Omote and Ayakuni

• Prior Art Relied Upon: Fu (Application # 2004/0070880), Omote (Patent 6,096,482), and Ayakuni (J.P. Application # 2002-009434A).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Fu provides the basic concept: a plated through-hole connection in a suspension to ground a component, avoiding conductive glue. However, Fu is not specific about the metal layers or wall geometry. Omote was cited to show that the specific layered structure claimed (sputtered chromium, sputtered copper, electroplated copper) was a well-known technique for creating conductive traces on stainless steel/polyimide substrates. Ayakuni was cited to show that forming apertures with wall slopes between 5 and 85 degrees was also a known technique to improve plating adhesion.
  • Motivation to Combine: A POSITA would combine these references as a matter of routine design. To implement Fu's general concept of a plated ground, a POSITA would naturally turn to well-known, optimized methods for layering (taught by Omote) and aperture formation (taught by Ayakuni) to ensure a reliable and robust connection.
  • Expectation of Success: Success would be expected because the combination involves applying standard, off-the-shelf process details (from Omote and Ayakuni) to a basic, known structure (from Fu). The similarities in technology and purpose across all three references would confirm the predictability of the outcome.
• Additional Grounds: Petitioner asserted an additional obviousness challenge against claims 6-7, 15-16, and 18-20 over Swanson in view of Naito. This ground relied on the same core arguments against Swanson from Ground 1, adding Naito solely to teach the specific aperture wall slope ranges required by these dependent and independent claims.

4. Key Claim Construction Positions

• "chromium": Petitioner argued that the ’679 patent is not entitled to its claimed provisional filing date (September 9, 2005) and is instead limited to its actual filing date (January 26, 2006). The argument centered on the term "chromium," for which the patent's specification provides an express definition that includes Monel—a nickel-copper alloy containing no chromium. Petitioner contended this broadened definition constituted new matter not supported by the provisional application, which only mentioned chromium or chromium alloys. This later effective filing date is critical to the petition, as it establishes several key references (e.g., Swanson, Aonuma) as prior art under 35 U.S.C. §102.

5. Relief Requested

• Petitioner requested institution of an inter partes review (IPR) and cancellation of claims 1-7, 15-16, and 18-20 of the ’679 patent as unpatentable.