Seoul Semiconductor Co Ltd v. LED Wafer Solutions LLC

1. Case Identification

• Case #: IPR2021-01516
• Patent #: 8,941,137
• Filed: September 10, 2021
• Petitioner(s): Seoul Semiconductor, Co. Ltd.
• Patent Owner(s): LED Wafer Solutions LLC
• Challenged Claims: 1-4, 7-8

2. Patent Overview

• Title: Light Emitting Diode Package and Method of Manufacture
• Brief Description: The ’137 patent discloses a vertical light-emitting diode (LED) device structure. The described invention is a Gallium Nitride (GaN)-based LED featuring a stacked-layer design with a top contact metal pad and a bottom contact metallic interface, allegedly improving upon conventional LED designs by addressing manufacturing complexities and heat dissipation.

3. Grounds for Unpatentability

Ground 1: Obviousness over Herrmann, Schubert/Nakamura, and Lee - Claims 1-3 and 7 are obvious over Herrmann in view of Schubert or Nakamura and Lee.

• Prior Art Relied Upon: Herrmann (referring to Application # 2010/0276706 and WO 2009/003442), Schubert (a 2006 textbook, Light-Emitting Diodes), Nakamura (Patent 5,777,350), and Lee (Application # 2008/0023721).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Herrmann, which describes a method for producing optoelectronic components, disclosed nearly every limitation of independent claim 1. Herrmann’s vertical LED structure allegedly taught a semiconductor LED with doped regions, a thin conducting support layer separated from the LED by a metallic interface, an optically permissive layer with phosphor particles, and a metal pad. The primary limitation Herrmann allegedly failed to explicitly disclose was the semiconductor LED including “intrinsic regions.” For dependent claim 3, Petitioner argued Herrmann disclosed a non-conductive passivation layer and taught modifications that would include a pair of apertures for electrical connections.
  • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine the references to solve known problems. Schubert and Nakamura both taught the known advantages of using an undoped, or “intrinsic,” active layer in an LED to improve radiative efficiency, enhance crystallinity, and lower forward voltage. A POSITA would thus be motivated to modify Herrmann’s LED to include an intrinsic active region to achieve these well-understood performance benefits. Furthermore, Lee taught using a harder, flat cover substrate over a softer phosphor-containing resin to improve reliability and prevent deformation. A POSITA would combine Lee’s teaching with Herrmann to protect the device, thereby arriving at the claimed "optically permissive flat cover substrate."
  • Expectation of Success: The proposed combinations involved implementing known solutions (using an intrinsic layer, adding a protective harder layer) to address predictable problems in a standard LED architecture. A POSITA would have had a high expectation of success as these were routine design modifications.

Ground 2: Obviousness over Herrmann, Schubert/Nakamura, Lee, and Hashimoto - Claim 4 is obvious over the combination of Ground 1 and Hashimoto.

• Prior Art Relied Upon: The combination from Ground 1, further in view of Hashimoto (Application # 2004/0012958).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground builds upon the combination asserted for claim 3. Dependent claim 4 adds the limitation that the passivation layer has a "shaped edge configured to reflect light." Petitioner asserted that Herrmann’s passivation layer had a vertical edge.
  • Motivation to Combine: The motivation to add Hashimoto’s teaching was to improve light extraction efficiency. Hashimoto explicitly taught that a vertical surface on a passivation layer can "hinder light from being released to the outside" and disclosed that shaping the edge with an incline improves light output. A POSITA would combine Hashimoto’s shaped edge with the device from Ground 1 to overcome this known issue and increase the brightness of the LED, a primary goal in LED design.
  • Expectation of Success: Shaping the edge of an encapsulant or passivation layer was a known and predictable technique for improving light extraction in the art.

Ground 3: Obviousness over Herrmann, Schubert/Nakamura, Lee, and Rothchild - Claim 8 is obvious over the combination of Ground 1 and Rothchild.

• Prior Art Relied Upon: The combination from Ground 1, further in view of Rothchild (Application # 2006/0104855).

• Core Argument for this Ground:

  • Prior Art Mapping: Dependent claim 8 requires that the "conducting support layer comprises copper." The conducting support layer in Herrmann was disclosed as a solder, such as a gold-tin alloy.
  • Motivation to Combine: The motivation for this combination was cost reduction. Rothchild taught lead-free solder alloys containing tin and copper as inexpensive and effective alternatives to precious-metal solders (like the gold-tin alloy of Herrmann). A POSITA seeking to manufacture LEDs economically would be strongly motivated to replace Herrmann's expensive gold-based solder with the low-cost, high-performance copper-containing solder taught by Rothchild. Rothchild also noted benefits of copper alloys like high thermal conductivity and low electrical resistance, which are desirable properties for an LED support layer.
  • Expectation of Success: Substituting one known solder material for another to reduce cost was a routine and predictable modification in electronics manufacturing.

• Additional Grounds: Petitioner asserted an additional obviousness challenge against claims 1 and 7 based on Beeson (Application # 2009/0140272) as the primary reference, combined with Schubert/Nakamura and Toshiba or Herrmann.

4. Key Claim Construction Positions

• Petitioner argued that the term "intrinsic," as used in "doped and intrinsic regions," should be construed to mean "undoped or not-doped." This construction was supported by the patent's specification, which contrasted "intrinsic regions" with "doped regions," and by extrinsic evidence from technical dictionaries. This construction was central to the obviousness arguments, as it framed the "intrinsic" limitation as a well-known design choice (leaving a layer undoped) rather than a novel feature.

5. Arguments Regarding Discretionary Denial

• Petitioner noted that it became aware of a separate inter partes review (IPR) petition filed by Samsung against the same ’137 patent (IPR2021-01506) shortly before filing its own. Petitioner asserted that there was no interaction between itself and Samsung regarding the substance of the petitions and that its own positions were substantially finalized before learning of the Samsung filing. This argument was presented to distinguish its petition and preemptively argue against discretionary denial under §325(d).

6. Relief Requested

• Petitioner requested the institution of an inter partes review and the cancellation of claims 1-4, 7, and 8 of the ’137 patent as unpatentable.