PTAB

IPR2018-00172

Broadcom Ltd v. Tessera Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Microelectronic Assemblies and Connection Components
  • Brief Description: The ’609 patent describes connection components for packaging microelectronic devices. The core technology involves using a two-part interposer structure, comprising a rigid first interposer and a more flexible second interposer, to manage thermal stress between a microelectronic element and a substrate.

3. Grounds for Unpatentability

Ground 1: Anticipation over Iyogi - Claims 1-3, 6-8, 10, 22-28, 40-42, 45-47, 55-58, and 70-72 are anticipated by Iyogi.

  • Prior Art Relied Upon: Iyogi (Japanese Patent Application Publication No. H8-64711).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Iyogi discloses every limitation of the challenged claims. Specifically, Iyogi’s "joined board," which consists of a "multilayer ceramic circuit board" and a "resin board," corresponds to the claimed "first interposer" and "second interposer." Petitioner asserted that the ceramic board is inherently more rigid than the "glass-cloth epoxy resin" board, meeting the relative flexibility limitation of claim 1. Iyogi’s through-holes filled with conductor (e.g., through-hole 5) and surface wiring layers (e.g., layer 4) were identified as the claimed "plurality of conductive structures." Finally, Petitioner contended that Iyogi’s disclosure of forming positions for solder balls inherently teaches the "plurality of planar leads" required to redistribute connections from the first interposer to an area-array pattern on the second interposer.
    • Key Aspects: The anticipation argument hinged on mapping the claimed two-interposer structure onto Iyogi's single "joined board" composed of two distinct materials with different mechanical properties.

Ground 2: Obviousness over Iyogi and Kato - Claims 4, 9, 11-21, 29-39, 43-44, 48-54, 59-69, and 73 are obvious over Iyogi in combination with Kato.

  • Prior Art Relied Upon: Iyogi (Japanese Patent Application Publication No. H8-64711) and Kato (Japanese Patent Application Publication No. H9-64236).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Iyogi teaches the base structure of a two-part interposer, and Kato provides teachings for specific features recited in the remaining dependent claims. For claims requiring flexible planar leads (e.g., claim 4), Kato was cited for its disclosure of flexible gold bumps. For claims requiring conductive portions extending along different axes (e.g., claim 9), Petitioner pointed to Kato’s disclosure of vertical direct through-holes (DTHs) and horizontal interstitial through-holes (IVHs). For claims reciting additional interposers (e.g., claim 14), Kato was cited for its teaching of stacking an "advanced layer" and a "base layer" which function as third and fourth interposers. Kato was also argued to teach packaging multiple microelectronic elements (e.g., claim 59) by disclosing the use of multiple SRAM chips.
    • Motivation to Combine: Petitioner asserted a person of ordinary skill in the art (POSITA) would combine Iyogi and Kato as both references are in the same field of chip packaging and address the same goals of high-density, high-reliability connections and stress resistance. A POSITA would have looked to Kato to implement or improve upon the basic structure in Iyogi, viewing Kato’s teachings as known, predictable solutions for enhancing connection configurations and accommodating more complex designs.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success in combining the references, as it involved applying known packaging techniques (e.g., using flexible leads, horizontal traces, stacking layers) from Kato to the analogous structures in Iyogi.

Ground 3: Obviousness over Iyogi - Claim 5 is obvious over Iyogi.

  • Prior Art Relied Upon: Iyogi (Japanese Patent Application Publication No. H8-64711).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that claim 5, which adds the limitation that the "planar leads are curved," would have been obvious based on Iyogi’s disclosure. While Iyogi does not explicitly show curved leads, its inherent disclosure of planar leads for signal redistribution would have led a POSITA to use well-known lead structures.
    • Motivation to Combine (with POSA Knowledge): Petitioner contended that at the time of the invention, it was well-known that surface leads in redistribution patterns were capable of bending or being formed with curvature (e.g., S-shaped) to manage stress. Therefore, modifying Iyogi’s planar leads to be curved was a simple and obvious design choice for a POSITA.

4. Key Claim Construction Positions

  • "first interposer": Petitioner proposed this term should be construed to include "relatively rigid interposers with two surfaces and electrical contacts on one of those surfaces." This construction was based on the specification’s description of the first interposer as "rigid."
  • "second interposer": Petitioner proposed this term should be construed to include "relatively flexible interposers with two surfaces, apertures, and terminals on one of those surfaces." This was based on the specification’s description of the second interposer as "flexible."
  • Importance: These constructions were central to Petitioner’s argument that Iyogi’s "joined board"—comprising a rigid ceramic part and a flexible resin part—met the limitations for the claimed first and second interposers.

5. Relief Requested

  • Petitioner requested the institution of an inter partes review and cancellation of claims 1-73 of the ’609 patent as unpatentable.