DCT

2:26-cv-00916

Mago Barca IP LLC v. SK hynix Inc

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: Mago Barca IP LLC v. SK hynix Inc., 2:26-cv-00916, E.D. Tex., 10/08/2026
  • Venue Allegations: Venue is alleged to be proper under the alien-venue rule, 28 U.S.C. § 1391(c)(3), on the basis that Defendant is a foreign corporation not resident in the United States.
  • Core Dispute: Plaintiff alleges that Defendant’s High-Bandwidth Memory (HBM) and DDR4 semiconductor memory products, and the processes used to make them, infringe five U.S. patents related to advanced semiconductor structures and fabrication methods.
  • Technical Context: The technology at issue involves solutions to manufacturing challenges in high-density semiconductors, specifically related to through-silicon via (TSV) interconnects for 3D stacked-die devices and source/drain contact structures for transistor-level components.
  • Key Procedural History: The complaint alleges that Plaintiff provided Defendant with written notice of infringement for all five asserted patents, including claim charts, starting on June 11, 2025. It further alleges that the parties engaged in subsequent technical and licensing discussions prior to the filing of the lawsuit, establishing a basis for pre-suit knowledge.

Case Timeline

Date Event
2008-06-27 '170 Patent Priority Date
2012-11-15 '914, '690, and '971 Patents Priority Date
2012-12-18 '170 Patent Issued
2015-11-03 '914 Patent Issued
2016-12-27 '690 Patent Issued
2018-05-29 '971 Patent Issued
2018-07-30 '877 Patent Priority Date
2022-08-09 '877 Patent Issued
2025-06-11 Plaintiff notice to Defendant re: '690, '971, '170, '877 Patents
2026-05-07 Plaintiff notice to Defendant re: '914 Patent
2026-10-08 Complaint Filed

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

U.S. Patent No. 9,177,914 - "Metal Pad Structure Over TSV to Reduce Shorting of Upper Metal Layer", issued November 3, 2015

The Invention Explained

  • Problem Addressed: The patent's background describes a problem in 3D integrated circuit manufacturing where the chemical-mechanical polishing (CMP) of large metal pads over through-substrate vias (TSVs) creates a "dishing effect," a recess in the pad's center. This topography can cause unintended "metal stringers" to form in subsequent layers, leading to electrical shorts '914 Patent, col. 1:49-65
  • The Patented Solution: The invention proposes replacing a solid metal pad with a "slotted metal pad." This structure is comprised of multiple metal bars separated by slots that are filled with a dielectric material '914 Patent, abstract This composite structure is designed to be more resistant to the dishing effect during CMP, thereby ensuring a more planar surface and preventing the formation of short-circuiting metal stringers in overlying interconnect layers '914 Patent, col. 3:24-30 '914 Patent, Figs. 3A-3B
  • Technical Importance: This design enables the reliable fabrication of large, planar contact pads over TSVs, a critical component for creating vertical interconnects in high-density, high-performance stacked-die packages without introducing yield-killing defects '914 Patent, col. 1:24-34

Key Claims at a Glance

  • The complaint asserts independent Claim 1 and dependent Claims 8, 9, 14, 15, and 17 Compl. ¶32
  • Independent Claim 1 requires:
    • A semiconductor die for bonding with another die, comprising:
    • a through substrate via (TSV) formed in a substrate of the semiconductor die; and
    • a slotted metal pad formed directly over the TSV,
    • wherein the slotted metal pad has a top surface area larger than a top surface area of the TSV,
    • wherein the slotted metal pad has a plurality of metal bars in a first direction, and
    • wherein slots between the plurality of metal bars are filled with a dielectric material to form dielectric bars.

U.S. Patent No. 9,530,690 - "Metal Pad Structure Over TSV to Reduce Shorting of Upper Metal Layer", issued December 27, 2016

The Invention Explained

  • Problem Addressed: This patent, a division of the application that led to the '914 Patent, addresses the same manufacturing problem: the "dishing effect" during CMP of large metal pads over TSVs, which can lead to short-circuits in upper metal layers '690 Patent, col. 2:1-12
  • The Patented Solution: The '690 Patent claims the method of creating the slotted metal pad structure. The claimed process involves forming openings in a dielectric layer, filling them with conductive and barrier materials, and then performing a planarization step that "does not cause significant dishing effect near a center of the slotted metal pad" '690 Patent, abstract '690 Patent, col. 8:15-32
  • Technical Importance: The invention provides a defined manufacturing process to create the slotted pad structure, aiming to improve fabrication yield and electrical reliability for advanced 3D integrated circuits '690 Patent, col. 1:15-22

Key Claims at a Glance

  • The complaint asserts independent Claim 1 and dependent Claims 2 and 3 Compl. ¶44
  • Independent Claim 1 requires a method with the following steps:
    • providing the substrate with the TSV;
    • forming a dielectric layer over the TSV;
    • forming openings in the dielectric layer... wherein the openings are connected and expose portions of the TSV;
    • depositing a diffusion barrier layer to line the openings;
    • depositing a conductive layer to gap-fill the openings; and
    • planarizing the layers to form a slotted metal pad, wherein the planarizing step "does not cause significant dishing effect near a center of the slotted metal pad."

Multi-Patent Capsule: U.S. Patent No. 9,984,971

  • Patent Identification: U.S. Patent No. 9,984,971, "Methods of Forming Metal Pad Structures Over TSVs to Reduce Shorting of Upper Metal Layers", issued May 29, 2018 Compl. ¶19
  • Technology Synopsis: Continuing the same inventive theme, the '971 Patent claims a semiconductor device structure that includes a pad formed directly over a TSV. The pad is defined by a plurality of metal bars and dielectric bars arranged in an alternating pattern in a region directly over the TSV, a structure intended to mitigate manufacturing defects '971 Patent, abstract Compl. ¶57
  • Asserted Claims: Claims 1, 2, 3, 4, 7, and 9 are asserted, with Claim 1 being independent Compl. ¶55
  • Accused Features: The Accused HBM Products are alleged to contain a pad structure over a TSV comprising an alternating pattern of metal and dielectric bars Compl. ¶57

Multi-Patent Capsule: U.S. Patent No. 11,410,877

  • Patent Identification: U.S. Patent No. 11,410,877, "Source/Drain Contact Spacers and Methods of Forming Same", issued August 9, 2022 Compl. ¶20
  • Technology Synopsis: This patent addresses a different technical area: reducing contact resistance in advanced transistors. It describes a "source/drain contact spacer" that is intentionally separated from the source/drain feature by a portion of a contact etch-stop layer '877 Patent, abstract This separation is alleged to prevent encroachment and improve current flow between the contact and the transistor's channel region '877 Patent, col. 2:56-65 Compl. ¶69
  • Asserted Claims: Claims 1, 2, 4, 7, and 9 are asserted, with Claim 1 being independent Compl. ¶66
  • Accused Features: The Accused DDR4 Products are alleged to incorporate a source/drain contact spacer that is physically separated from the source/drain feature by a remaining portion of an etch-stop layer Compl. ¶69

Multi-Patent Capsule: U.S. Patent No. 8,334,170

  • Patent Identification: U.S. Patent No. 8,334,170, "Method for Stacking Devices", issued December 18, 2012 Compl. ¶21
  • Technology Synopsis: This patent claims a method for fabricating stacked semiconductor devices that aims to reduce thermal stress. Instead of curing the coating (underfill) material between each pair of stacked dies individually, the method involves applying multiple layers of uncured coating material between successive devices and then curing them all "in a same process" '170 Patent, abstract This single thermal cycle for multiple layers is intended to mitigate the cumulative stress and potential defects caused by repeated heating '170 Patent, col. 1:36-47
  • Asserted Claims: Claims 1, 3, and 4 are asserted, with Claim 1 being independent Compl. ¶¶77-78
  • Accused Features: Plaintiff alleges on information and belief that the manufacturing process for the Accused HBM Products involves applying successive layers of coating material between dies and subsequently curing multiple of these layers in the same process Compl. ¶81

III. The Accused Instrumentality

  • Product Identification: The complaint identifies two categories of accused products: "Accused HBM Products" and "Accused DDR4 Products" Compl. ¶¶4-5
    • Representative HBM products include the SK hynix H5UG7HMD83X020R HBM3 SDRAM Compl. ¶4
    • Representative DDR4 products include the SK hynix H5AN8G8NJJR-VKC DDR4 SDRAM and the HMA84GR7DJR4N-XN DDR4 module Compl. ¶5
  • Functionality and Market Context:
    • The Accused HBM Products are described as high-bandwidth memory developed for high-performance applications such as data centers, supercomputers, and artificial intelligence, which utilize "stacks of DRAM dies" Compl. ¶23 The infringement allegations against these products are based on reverse engineering of their TSV and metal-pad-over-TSV structures Compl. ¶¶24, 33
    • The Accused DDR4 Products are DRAM devices that allegedly incorporate specific source/drain-contact structures Compl. ¶5 The infringement allegations are based on reverse engineering that identified a source/drain contact spacer allegedly separated from the source/drain feature by an etch-stop layer Compl. ¶¶67, 69 The complaint includes a transmission electron microscopy (TEM) cross-section image from its analysis of the accused DDR4 device Compl. ¶67, Fig. 1

IV. Analysis of Infringement Allegations

'914 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
a through substrate via (TSV) formed in a substrate of the semiconductor die The Accused HBM Products are alleged to contain a TSV formed in a semiconductor substrate, as shown in a cross-sectional SEM image. ¶33 col. 3:3-5
a slotted metal pad formed directly over the TSV Reverse engineering allegedly identifies a slotted metal pad directly over the TSV. ¶34 col. 3:6-7
wherein the slotted metal pad has a top surface area larger than a top surface area of the TSV The complaint provides a top-view image comparing the pad and TSV areas, alleging the pad's area is larger. ¶34 col. 3:8-9
wherein the slotted metal pad has a plurality of metal bars in a first direction The accused pad allegedly comprises multiple metal bars oriented in a first direction. ¶34 col. 3:10-11
and wherein slots between the plurality of metal bars are filled with a dielectric material to form dielectric bars The complaint alleges that slots in the accused pad are filled with a dielectric material (identified as oxide) to form dielectric bars. ¶34 col. 3:12-14
  • Identified Points of Contention:
    • Technical Questions: The infringement analysis will likely depend on factual evidence derived from reverse engineering. A potential point of contention could be whether the accused structure's features meet the specific dimensional and material requirements of the asserted dependent claims, such as the width of the dielectric bars being "greater than about 0.4 µm" as required by Claim 15 Compl. ¶38
    • Scope Questions: The dispute may raise questions about the precise definition of a "slotted metal pad." For example, the defense may argue that the accused structure, while not a solid pad, does not meet the specific configuration of a "slotted" pad as contemplated by the patent, potentially arguing for a narrower construction based on the patent's embodiments.

'690 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
providing the substrate with the TSV; Plaintiff alleges the Accused HBM Products are made by a process that begins with a substrate containing a TSV. ¶45 col. 8:17-18
forming a dielectric layer over the TSV; Based on the observed final structure, it is alleged that the process includes forming a dielectric layer over the TSV. ¶45 col. 8:19
forming openings in the dielectric layer, wherein the openings are connected and expose portions of the TSV, wherein there are dielectric structures of the dielectric layer amongst the openings; Allegedly, the process involves forming connected openings in the dielectric layer that expose the TSV, based on inference from the final product structure. ¶46 col. 8:20-24
depositing a diffusion barrier layer to line the openings; Based on material analysis of the final product, Plaintiff alleges the process includes depositing a diffusion barrier layer. ¶47 col. 8:25-26
depositing a conductive layer to gap-fill the openings; and It is alleged the process includes depositing a conductive layer to fill the openings. ¶47 col. 8:27-28
planarizing the conductive layer and the diffusion barrier layer ... to form a slotted metal pad, wherein the step of planarizing does not cause significant dishing effect near a center of the slotted metal pad. Plaintiff alleges the process includes a planarization step that, based on the observed planarity of the final product, does not cause significant dishing. ¶48 col. 8:29-32
  • Identified Points of Contention:
    • Evidentiary Questions: As these are method claims asserted under 35 U.S.C. § 271(g), infringement hinges on proving that the imported Accused HBM Products were made by the patented process. The complaint infers the process steps from the final product's structure Compl. ¶24 A key challenge for the plaintiff will be to demonstrate that the observed structure could only be produced by the claimed method.
    • Technical Questions: A central dispute will likely concern the negative limitation "does not cause significant dishing effect." The complaint alleges this is met because the completed structure appears planar Compl. ¶48 The case may turn on the definition of "significant" and the evidence required to prove the absence of such an effect in a manufacturing process that is not directly observed.

V. Key Claim Terms for Construction

For the '914 Patent:

  • The Term: "slotted metal pad"
  • Context and Importance: This term defines the core structural element of the invention. Its construction will determine the range of pad designs that fall within the claim's scope. Practitioners may focus on this term because the defendant could argue its pad design, while non-solid, is a distinct alternative rather than a "slotted" one.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The patent generally describes the structure as having "openings filled with dielectric material" '914 Patent, col. 3:24-25, which could be argued to cover any pattern of metal and dielectric, not just linear slots.
    • Evidence for a Narrower Interpretation: The embodiments consistently depict the pad as comprising parallel, linear metal bars separated by parallel dielectric bars '914 Patent, Fig. 3B This could support an argument to limit the term to this specific geometric arrangement.

For the '690 Patent:

  • The Term: "does not cause significant dishing effect"
  • Context and Importance: This negative limitation is crucial for proving infringement of the method claim, as it defines the required outcome of the planarization step. Its inherent subjectivity makes it a prime candidate for claim construction. Practitioners may focus on this term because proving a negative, especially one qualified by "significant," is a high evidentiary bar.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation (Favorable to Plaintiff): The patent's goal is to prevent "metal stringers" '690 Patent, col. 2:9-12 One could argue that any dishing that is insufficient to cause stringers is not "significant" in the context of the patent.
    • Evidence for a Narrower Interpretation (Favorable to Defendant): The specification states the invention reduces the dishing "to none or almost none" '690 Patent, col. 3:43-45 This language may support a very strict interpretation, where nearly any measurable dishing is "significant," making infringement harder to prove.

VI. Other Allegations

  • Indirect Infringement: For method patents like the '690 and '170, the primary allegation is infringement under 35 U.S.C. § 271(g) for importing, selling, or using a product made by a patented process Compl. ¶¶44, 78 The complaint also alleges facts that could support inducement, stating that SK hynix supplies the Accused Products for incorporation into downstream systems and provides technical materials and customer support to facilitate their use Compl. ¶11
  • Willful Infringement: The complaint pleads willful infringement for all five asserted patents. The basis for willfulness is alleged pre-suit and post-suit knowledge of the patents and the infringement allegations. The complaint provides specific dates for written notices sent to SK hynix, which included claim charts, and alleges that the defendant continued its infringing conduct after receiving these notices and participating in licensing discussions Compl. ¶¶25-30 Compl. ¶40 Compl. ¶52 Compl. ¶63 Compl. ¶74 Compl. ¶86

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

  • A central issue will be one of process reconstruction and negative limitations: For method claims covering the TSV pad '690 Patent and die stacking '170 Patent, can the plaintiff prove, by analyzing the final imported products, that Defendant’s unobserved manufacturing process must have included the claimed steps, particularly the step of planarizing without causing "significant dishing"?
  • A second core issue will be one of structural scope: For the device patents ('914, '971, '877 Patents), the case will turn on whether the physical structures identified in Defendant’s HBM and DDR4 products, as revealed through reverse engineering, fall within the scope of key claim terms like "slotted metal pad" and a contact spacer that "does not physically contact the source/drain feature."
  • Finally, a key evidentiary question will be one of measurement and degree: Given claims that recite specific dimensions (e.g., "greater than about 0.4 µm") or relative characteristics (e.g., "larger than," "wider than"), the dispute will likely involve a battle of experts interpreting microscopic imaging evidence to determine if these quantitative and qualitative thresholds are met.