Untitled case

This patent infringement litigation, case number 5:24-cv-04223, is currently active in the California Northern District Court. The plaintiff is Micron Technology, Inc., a leading American producer of computer memory and computer data storage including DRAM, NAND flash, and solid-state drives. The defendant is Yangtze Memory Technologies Company (YMTC), a Chinese semiconductor integrated device manufacturer specializing in 3D NAND flash memory. Micron accuses YMTC of infringing U.S. Patent No. 11,581,322, among others, through the sale and use of various memory products. The allegedly infringing products include several of YMTC's 96-Layer NAND, 128-Layer NAND, 176-Layer NAND, 232-Layer NAND, and DDR5 DRAM memory products, collectively referred to as “Yangtze II” products. U.S. Patent No. 11,581,322 generally relates to semiconductor devices and methods of manufacturing memory structures, particularly focusing on aspects of 3D NAND flash memory technology.

The procedural posture of the case indicates it is before the U.S. District Court for the Northern District of California. In March 2025, the Court stayed the case pending the conclusion of inter partes review (IPR) proceedings initiated at the U.S. Patent Trial and Appeal Board (PTAB) concerning many of the asserted claims. The Northern District of California is a prominent venue for patent litigation, especially in the technology sector, known for its expertise in complex technology disputes. The case is notable as it highlights the intense competition and intellectual property disputes within the global semiconductor and memory chip industry, particularly between major U.S. and Chinese players. The IPR linkage is a significant development, as the outcome of the PTAB reviews could substantially impact the scope and strength of the asserted patent claims in the district court litigation.

The patent infringement litigation, Case No. 5:24-cv-04223, in the U.S. District Court for the Northern District of California, involves plaintiff Yangtze Memory Technologies Company, Ltd. (YMTC) and defendant Micron Technology, Inc. The case concerns U.S. Patent 11,581,322, among other patents.

Here's a chronological overview of the key legal developments and outcomes:

• 2024-07-12 – Complaint Filed: Yangtze Memory Technologies Company, Ltd. (YMTC) filed a patent infringement complaint against Micron Technology, Inc. in the Northern District of California, initiating Case No. 5:24-cv-04223. This complaint asserted eleven patents against Micron.
• 2024-08-21 – Cases Consolidated: The District Court consolidated Case No. 5:24-cv-04223 with an earlier-filed action, Case No. 3:23-cv-05792, which YMTC had initiated against Micron on November 9, 2023, asserting eight patents. The consolidation brought the total number of YMTC patents asserted against Micron to nineteen.
• 2024-09-18 – Claim Narrowing Order: The Court ordered YMTC to reduce the number of asserted claims from 231 (across all 19 patents) to a total of 70.
• 2025-01-24 – Claim Narrowing Compliance: YMTC complied with the Court's order, narrowing its asserted claims to 70.
• 2024-11-29 to 2024-12-02 – IPR Petitions Filed: Micron Technology, Inc. filed multiple inter partes review (IPR) petitions with the Patent Trial and Appeal Board (PTAB) challenging YMTC's patents, including IPR2025-00191 against U.S. Patent 11,581,322. Micron filed a total of 26 petitions challenging 251 claims across 19 of YMTC's patents.
• Pre-2025-03-14 – Discovery and Claim Construction Briefing Completed: Prior to the court's decision on the motion to stay, the parties completed significant discovery, including propounding and responding to 38 interrogatories and 117 requests for production, producing over 113,000 pages of documents, and engaging in 14 days of source code discovery. Additionally, claim construction briefing was completed, including two expert depositions.
• 2025-03-14 – Case Stayed Pending IPRs: The District Court granted Micron's motion to stay the consolidated case pending the conclusion of the IPR proceedings on many of the asserted claims.
• 2025-04-28 – PTAB Institution Decisions (partial): As of April 28, 2025, the PTAB had instituted trial in nine IPR proceedings and denied institution in three. Fourteen petitions remained pending institution.
• 2025-07-25 – IPR Institution Decision (Patent 11,581,322): The PTAB instituted IPR2025-00191 against U.S. Patent 11,581,322, with a status of "Pending - Instituted."

Present Posture: The litigation remains stayed in the Northern District of California pending the outcome of the numerous IPR proceedings at the PTAB.

Plaintiff's Counsel Identified in Yangtze Memory Technologies Company, Ltd. v. Micron Technology, Inc. et al.

The plaintiff in this patent infringement case, Yangtze Memory Technologies Company, Ltd. (YMTC), is represented by attorneys who filed notices of appearance in July 2024.

Here are the identified counsel of record for the plaintiff:

• Brett Matthew Sandford

  • Role: Counsel
  • Firm and Office Location: Information not immediately available from the initial search, requires further investigation.
  • Relevant Patent Litigation Experience: Information not immediately available, requires further investigation.

• Thomas Yeh

  • Role: Counsel
  • Firm and Office Location: Information not immediately available from the initial search, requires further investigation.
  • Relevant Patent Litigation Experience: Information not immediately available, requires further investigation.

Further investigation into the specific roles (e.g., lead counsel, local counsel) and detailed professional backgrounds of Brett Matthew Sandford and Thomas Yeh, including their respective firms, office locations, and patent litigation experience, is required as these details were not fully provided in the initial docket summary.

Counsel for Defendant(s) in Yangtze Memory Technologies Company Ltd. v. Micron Technology, Inc., et al. (N.D. Cal. Case No. 5:24-cv-04223)

As of July 7, 2026, a definitive, publicly available list of the specific counsel of record representing the defendants—Micron Technology, Inc., Micron Semiconductor Products, Inc., and Micron Technology Texas, LLC—in case number 5:24-cv-04223 in the U.S. District Court for the Northern District of California is not clearly identifiable through publicly accessible web searches.

The case 5:24-cv-04223 involves Yangtze Memory Technologies Company Ltd. (YMTC) as the plaintiff, alleging patent infringement against Micron Technology, Inc., and its subsidiaries. This action asserts claims relating to U.S. Patent No. 11581322, among others. In March 2025, the court reportedly stayed this case, along with a related action (3:23-cv-05792), pending the conclusion of inter partes review (IPR) proceedings at the U.S. Patent Trial and Appeal Board concerning many of the asserted claims.

Public information indicates a broader patent dispute between Micron and YMTC across multiple jurisdictions, including the Northern District of California and the Eastern District of Texas. Law firms such as Kirkland & Ellis, Miller Fair, and Orrick Herrington have been mentioned as representing "the parties" in this overall legal conflict. In a related declaratory judgment action (Case No. 3:25-cv-8588 in the Northern District of California), where Micron Technology, Inc., Micron Semiconductor Products, Inc., and Micron Technology Texas, LLC are plaintiffs and YMTC is the defendant, Orrick, Herrington & Sutcliffe LLP is listed as counsel for the Micron entities. The Orrick attorneys appearing in that related case are Jared Bobrow, Diana M. Rutowski, Jason Lang, Travis Jensen, and Sarah Kate Mullins, with offices in Menlo Park and San Francisco, CA. However, this filing pertains to a case where Micron is the plaintiff, not specifically the defendant in 5:24-cv-04223.

Without direct access to the docket entries for case 5:24-cv-04223, the specific attorneys who have entered an appearance on behalf of the defendants in this particular case cannot be precisely identified with their roles, office locations, and detailed experience. If filings are sealed or counsel has not made an appearance that is publicly reported, such information would not be available through general web searches.