DCT

1:24-cv-00342

Godo Kaisha IP Bridge 1 v. Western Digital Tech Inc

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:24-cv-00342, D. Del., 07/08/2024
  • Venue Allegations: Venue is alleged to be proper in the District of Delaware because both Defendant entities are incorporated in the State of Delaware.
  • Core Dispute: Plaintiff alleges that Defendants’ hard disk drives and their internal read/write heads infringe nine U.S. patents related to Magnetic Tunnel Junction (MTJ) technology.
  • Technical Context: The patents relate to the structure of MTJs, a nanoscale component in hard disk drive read/write heads that enables the detection of magnetic bits, with the patented inventions claiming to significantly increase data storage density and performance.
  • Key Procedural History: The complaint alleges that Defendants were aware of the foundational work of the inventor, Dr. Shinji Yuasa, and had specific knowledge of the lead patent-in-suit (U.S. Patent No. 7,884,403) no later than September 2022, based on an international search report for one of Defendants' own patent applications that cited the '403 patent's published application as relevant prior art.

Case Timeline

Date Event
2004-03-12 Earliest Priority Date for all Asserted Patents
2011-02-08 U.S. Patent No. 7,884,403 Issued
2012-11-27 U.S. Patent No. 8,319,263 Issued
2013-03-26 U.S. Patent No. 8,405,134 Issued
2015-09-01 U.S. Patent No. 9,123,463 Issued
2017-03-28 U.S. Patent No. 9,608,198 Issued
2018-03-01 Alleged timeframe for infringing products begins
2019-07-30 U.S. Patent No. 10,367,138 Issued
2020-06-09 U.S. Patent No. 10,680,167 Issued
2022-09-01 Alleged knowledge date for '403 Patent by Defendant
2023-08-22 U.S. Patent No. 11,737,372 Issued
2024-04-23 U.S. Patent No. 11,968,909 Issued
2024-07-08 First Amended Complaint Filed

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 7,884,403 - "Magnetic Tunnel Junction Device and Memory Device Including the Same"

  • Patent Identification: U.S. Patent No. 7,884,403, "Magnetic Tunnel Junction Device and Memory Device Including the Same," issued February 8, 2011 (’403 Patent).

The Invention Explained

  • Problem Addressed: The patent’s background describes that conventional Magnetic Tunnel Junction (MTJ) devices, which are critical components in MRAM and hard drive read heads, used an amorphous aluminum-oxide (Al-O) tunnel barrier. These devices exhibited a relatively small magnetoresistance (MR) effect, which limited their output voltage and, consequently, the density and reliability of memory devices built with them (’403 Patent, col. 2:45-56).
  • The Patented Solution: The invention replaces the amorphous Al-O barrier with a highly-ordered, crystalline magnesium-oxide (MgO) layer, specifically one where the (001) crystal plane is preferentially oriented (’403 Patent, col. 4:1-4). This crystalline structure is intended to prevent the scattering of electrons as they "tunnel" through the barrier, a phenomenon described as coherent tunneling, which dramatically increases the MR ratio (’403 Patent, col. 5:26-34). The patent further discloses that creating oxygen vacancy defects in the MgO layer can lower its potential barrier height, which in turn reduces electrical resistance and increases tunneling current (’403 Patent, col. 7:6-12). A diagram from an HGST (a Western Digital company) presentation included in the complaint illustrates the inventor's groundbreaking results with this Fe/MgO/Fe structure (Compl. p. 10, ¶23).
  • Technical Importance: This shift from amorphous to crystalline tunnel barriers provided a significant leap in the MR ratio, reportedly doubling the output voltage over the prior art and enabling the development of much higher-density hard disk drives and MRAM (’403 Patent, col. 9:15-24).

Key Claims at a Glance

  • The complaint asserts at least claim 5, which depends on independent claim 1 (Compl. ¶50).
  • The essential elements of independent claim 1 are:
    • A magnetoresistive device comprising a tunnel barrier junction structure.
    • A first ferromagnetic material layer of a Body-Centered Cubic (BCC) structure.
    • A second ferromagnetic material layer of a BCC structure.
    • A tunnel barrier layer located between the first and second ferromagnetic layers.
    • The tunnel barrier layer is formed by a single-crystalline MgOx (001) layer or a poly-crystalline MgOx (0<x<1) layer in which the (001) crystal plane is preferentially oriented.
    • The tunnel barrier layer has a tunnel barrier height in a range of 0.2 to 0.5 eV.

U.S. Patent No. 8,319,263 - "Magnetic Tunnel Junction Device"

  • Patent Identification: U.S. Patent No. 8,319,263, "Magnetic Tunnel Junction Device," issued November 27, 2012 (’263 Patent).

The Invention Explained

  • Problem Addressed: The patent addresses the same technical challenge as the ’403 Patent: the low MR ratio and output voltage of prior art MTJ devices, which hindered the development of high-density memory technologies (’263 Patent, col. 2:45-56).
  • The Patented Solution: The invention is directed to a similar MTJ structure featuring a crystalline MgO tunnel barrier, but specifically claims the use of an amorphous magnetic alloy, CoFeB, for the ferromagnetic electrodes (’263 Patent, Fig. 11; col. 9:8-17). The patent explains that while the electrodes are initially amorphous, an annealing process after fabrication can cause them to crystallize, thereby achieving the high MR ratio associated with a fully crystalline structure (’263 Patent, col. 9:20-27). This approach potentially simplifies manufacturing compared to epitaxially growing crystalline electrodes from the start.
  • Technical Importance: The use of CoFeB electrodes that crystallize during annealing provided a commercially viable path to mass-produce high-performance MTJ devices with the high MR ratios enabled by crystalline MgO barriers (Compl. ¶¶ 10, 17, general context).

Key Claims at a Glance

  • The complaint asserts at least independent claim 1 (Compl. ¶87).

  • The essential elements of independent claim 1 are:

    • A magnetoresistive device having a tunnel barrier junction structure.
    • A first ferromagnetic material layer of a BCC structure.
    • A second ferromagnetic material layer of a BCC structure.
    • A tunnel barrier layer between the first and second ferromagnetic layers, comprising a single-crystalline or poly-crystalline magnesium oxide layer in which the (001) crystal plane is preferentially oriented.
    • The tunnel barrier layer has a tunnel barrier height in a range of 0.2 to 0.5 eV.
    • At least one of the first and second ferromagnetic material layers comprises a CoFeB alloy.
      The complaint asserts nine patents in total. Per the instructions for multi-patent cases, the remaining seven patents are summarized below.

  • Patent Identification: U.S. Patent No. 11,737,372, "Method of Manufacturing a Magnetoresistive Random Access Memory (MRAM)," issued August 22, 2023.

  • Technology Synopsis: This patent claims methods for manufacturing MTJ devices. The claimed steps involve forming amorphous CoFeB electrode layers on either side of a poly-crystalline MgO barrier layer and then performing an annealing step to crystallize the layers (’372 Patent, Claim 1).

  • Asserted Claims: At least claim 1 (Compl. ¶106).

  • Accused Features: The manufacturing processes used by Defendants to create the read/write heads in their HDDs (Compl. ¶106).

  • Patent Identification: U.S. Patent No. 11,968,909, "Method of manufacturing a magnetoresistive random access memory (MRAM)," issued April 23, 2024.

  • Technology Synopsis: This patent is also directed to manufacturing methods. It claims a process of forming a multi-layer MTJ stack and specifies that the tunnel barrier comprises crystalline MgO with oxygen vacancy defects (’909 Patent, Claim 1).

  • Asserted Claims: At least claim 1 (Compl. ¶125).

  • Accused Features: Defendants' manufacturing processes for the read/write heads in their HDDs (Compl. ¶125).

  • Patent Identification: U.S. Patent No. 10,367,138, "Magnetic tunnel junction device," issued July 30, 2019.

  • Technology Synopsis: This patent claims a device structure for an MTJ. The claims focus on a device with entirely crystallized CoFeB electrodes and a poly-crystalline MgO barrier layer with a preferentially oriented (001) crystal plane (’138 Patent, Claim 12).

  • Asserted Claims: At least claim 12 (Compl. ¶144).

  • Accused Features: The read/write heads within Defendants' HDD products (Compl. ¶144).

  • Patent Identification: U.S. Patent No. 9,608,198, "Magnetic tunnel junction device," issued March 28, 2017.

  • Technology Synopsis: This patent claims an MTJ device comprising a tunnel barrier layer disposed between first and second ferromagnetic material layers. The claims require the tunnel barrier to be a poly-crystalline magnesium oxide layer with a (001) crystal plane preferentially oriented, and for the first ferromagnetic layer to be a crystallized CoFeB alloy (’198 Patent, Claim 1).

  • Asserted Claims: At least claim 1 (Compl. ¶163).

  • Accused Features: The read/write heads within Defendants' HDD products (Compl. ¶163).

  • Patent Identification: U.S. Patent No. 9,123,463, "Magnetic tunnel junction device," issued September 1, 2015.

  • Technology Synopsis: This patent claims an MTJ device structure. It requires a tunnel barrier layer comprising a crystalline magnesium oxide layer with a (001) crystal plane, where the first ferromagnetic layer is a crystallized CoFeB alloy and the second may also be a crystallized CoFeB alloy (’463 Patent, Claims 1-2).

  • Asserted Claims: At least claim 1 (Compl. ¶182).

  • Accused Features: The read/write heads within Defendants' HDD products (Compl. ¶182).

  • Patent Identification: U.S. Patent No. 10,680,167, "Magnetic tunnel junction device," issued June 9, 2020.

  • Technology Synopsis: This patent claims a method of manufacturing an MTJ device. The method involves forming amorphous CoFeB layers around a poly-crystalline MgO barrier and then annealing to crystallize the stack, with the claims specifying the crystalline orientation and BCC structure of the final product (’167 Patent, Claim 1).

  • Asserted Claims: At least claim 1 (Compl. ¶201).

  • Accused Features: The manufacturing processes for the read/write heads in Defendants' HDDs (Compl. ¶201).

  • Patent Identification: U.S. Patent No. 8,405,134, "Magnetic tunnel junction device," issued March 26, 2013.

  • Technology Synopsis: This patent claims an MTJ device structure. It is directed to a crystallized CoFeB electrode, a crystalline MgO barrier, and specifies the method for determining the barrier height via J-V curve fitting using the Simmons' formula (’134 Patent, Claim 1).

  • Asserted Claims: At least claim 1 (Compl. ¶204).

  • Accused Features: The read/write heads within Defendants' HDD products (Compl. ¶204).

III. The Accused Instrumentality

Product Identification

The accused instrumentalities are read/write heads for hard disk drives (“HDDs”), the HDDs that incorporate them, and all associated hardware sold by Defendants since March 2018 (Compl. ¶41). The complaint lists numerous product lines, including WD Blue, WD Purple, WD Red, WD_BLACK, Ultrastar, HGST, My Passport, SanDisk Professional, and G-Technology HDDs (Compl. ¶42).

Functionality and Market Context

The complaint alleges that the accused products incorporate read/write heads that utilize the patented MTJ technology to read data from and write data to magnetic disks (Compl. ¶¶ 10, 41). The core of the allegation is that this technology, which allows for a high magnetoresistance ratio, is what enables the high-density storage capacity of modern HDDs (Compl. ¶10). The complaint includes a diagram explaining the basic principle of Tunnel MagnetoResistance (TMR), where the electrical resistance of the MTJ changes based on the magnetic alignment of its layers, allowing a bit to be read as a '0' or a '1' (Compl. p. 6). The complaint posits that this technology is fundamental to the operation and commercial success of Defendants' storage products (Compl. ¶¶ 11, 25).

IV. Analysis of Infringement Allegations

The complaint incorporates infringement allegations by reference to exhibits that are not provided in the filed document (Compl. ¶¶ 51, 88). Accordingly, a claim chart summary cannot be constructed. The narrative infringement theories are summarized below.

Summary for '403 Patent (Claim 5)

The complaint alleges that Defendants' HDDs contain MTJ devices that meet every limitation of claim 5 (Compl. ¶51). This implies the accused devices have a structure with first and second ferromagnetic layers of a BCC structure sandwiching a tunnel barrier. That barrier is alleged to be a single-crystalline or poly-crystalline MgOx layer with a preferentially oriented (001) crystal plane and a specific electrical barrier height between 0.2 and 0.5 eV, consistent with the patent's teachings on using crystalline MgO with oxygen vacancy defects (’403 Patent, Claim 1). A diagram from the patent, included in the complaint, illustrates this layered Fe/MgO/Fe structure (Compl. p. 8, Fig. 1(B), ¶18).

Summary for '263 Patent (Claim 1)

The complaint alleges that the accused HDDs meet all limitations of claim 1, which requires a similar MTJ structure but specifies that at least one of the ferromagnetic layers comprises a CoFeB alloy (Compl. ¶88). The infringement allegation therefore centers on the assertion that Defendants' devices use CoFeB electrodes in conjunction with a crystalline MgO barrier having the claimed electrical properties (’263 Patent, Claim 1).

Identified Points of Contention

  • Evidentiary Questions: The complaint's infringement theory relies heavily on the public recognition of Dr. Yuasa's work and its adoption by the HDD industry, including by Defendants (Compl. ¶¶ 23-28). A primary point of contention will be the direct evidence Plaintiff offers to prove that the accused products actually contain the specific material compositions (e.g., CoFeB), crystalline structures (e.g., preferentially oriented (001) MgO), and electrical properties (e.g., barrier height of 0.2-0.5 eV) recited in the claims.
  • Scope Questions: The case may raise questions about the scope of the claimed electrical properties. For instance, a dispute could arise over the precise method of measuring the "tunnel barrier height" and whether Defendants' products, if measured differently, would fall outside the claimed 0.2 to 0.5 eV range.

V. Key Claim Terms for Construction

  • The Term: "a tunnel barrier height . . . in a range of 0.2 to 0.5 eV" (present in independent claim 1 of both the ’403 and ’263 Patents).

  • Context and Importance: This limitation is central to defining the invention, as it quantifies a key physical property that distinguishes the patented device from the prior art. The infringement analysis for both lead patents will depend on whether the accused devices can be shown to possess this specific electrical characteristic. Practitioners may focus on this term because its definition is tied to a specific measurement methodology described in the patents.

  • Intrinsic Evidence for Interpretation:

    • Evidence for a Broader Interpretation: The claims themselves state the required range without tying it to a specific measurement technique. A party might argue that any scientifically valid method demonstrating the barrier height falls within this range is sufficient to prove infringement.
    • Evidence for a Narrower Interpretation: The specifications of the patents explicitly describe determining the barrier height by "fitting the electric conductance characteristics of the MTJ device ... onto the Simmons' formula" (’403 Patent, col. 7:30-35). A party could argue that this definition from the specification limits the claim scope, requiring that infringement be proven using the same methodology. The patent contrasts this 0.2-0.5 eV range with the much higher barrier height of an "ideal tunnel barrier height of a MgO crystal" (~3.6 eV), linking the claimed range to the presence of oxygen vacancy defects (’403 Patent, col. 7:6-18).

  • The Term: "poly-crystalline MgOx (0<x<1) layer in which a (001) crystal plane is preferentially oriented" (present in independent claim 1 of both the ’403 and ’263 Patents).

  • Context and Importance: This term defines the specific crystalline structure of the tunnel barrier, which is the core structural innovation alleged to enable coherent tunneling and high MR ratios. Infringement will require proof that the accused devices contain a barrier with this exact atomic-level arrangement.

  • Intrinsic Evidence for Interpretation:

    • Evidence for a Broader Interpretation: A party might argue that "preferentially oriented" does not require perfect or near-perfect alignment and could encompass a range of crystalline qualities, so long as a dominant (001) orientation exists.
    • Evidence for a Narrower Interpretation: The specification repeatedly contrasts the invention with the "amorphous Al-O" barrier of the prior art, emphasizing the importance of an "orderly fashion" of atoms (’403 Patent, col. 2:47-49; Compl. ¶18). The description of epitaxially growing the MgO layer on a Fe(001) layer suggests that a high degree of crystalline order is contemplated (’403 Patent, col. 6:37-43). This context may support a narrower construction requiring a significant and measurable preference for the (001) orientation.

VI. Other Allegations

Indirect Infringement

The complaint alleges that Defendants induce infringement by actively encouraging customers and third-party resellers (e.g., Best Buy) to use, sell, and offer for sale the accused HDDs. This encouragement is alleged to occur through websites, user manuals, product documentation, and other advertising materials (Compl. ¶¶ 63-66, 90-93). The complaint also alleges contributory infringement, stating the accused products are not staple articles of commerce and that their read/write heads are a material part of the invention (Compl. ¶¶ 74-76, 98-100).

Willful Infringement

The complaint makes detailed allegations of willful infringement regarding the '403 Patent based on alleged pre-suit knowledge (Compl. ¶¶ 78-83). The primary basis is Defendants' alleged awareness of the inventor's work and, specifically, the '403 patent application, dating to at least September 2022. The complaint provides an image of an International Search Report from the prosecution of one of Defendants' own patent applications, which lists the '403 patent's application as the "closest prior art" (Compl. p. 18, ¶55). The complaint follows this with an image of an Information Disclosure Statement (IDS) where Defendants submitted that reference to the USPTO, arguing this demonstrates direct knowledge (Compl. p. 19, ¶59).

VII. Analyst’s Conclusion: Key Questions for the Case

  • A core issue will be one of evidentiary proof: What direct technical evidence, such as from device teardowns or materials analysis, can Plaintiff produce to demonstrate that Defendants’ mass-produced HDD read/write heads contain the specific crystalline structures (e.g., preferentially oriented MgO) and exhibit the narrow electrical properties (e.g., a tunnel barrier height of 0.2 to 0.5 eV) recited in the asserted claims?
  • A central question for damages will be willfulness: Given the complaint's evidence that Defendants identified the '403 patent's application as highly relevant prior art during their own patent prosecution, the case will likely focus on what knowledge can be imputed to Defendants from that event and whether their subsequent conduct rises to the level of willful infringement.
  • A key legal question will be one of claim construction: How will the court construe the term "tunnel barrier height"? The outcome may depend on whether the definition is limited to the specific measurement methodology detailed in the patent's specification, which could significantly impact how infringement is proven or disproven.