Yangtze Memory urges U.S. district court to lift stay on three-year 3D NAND patent infringement litigation against Micron

Context:

• In late 2022, the United States Department of Commerce (DOC) added Yangtze Memory Technologies Corp. (YMTC) to the Entity List (a trade restriction list), effectively shutting it out of the U.S. market for 3D NAND flash memory. YMTC then sued Micron Technology in the U.S. District Court for the Northern District of California in November 2023, over the alleged infringement of eight patents related to 3D NAND technology. It filed another complaint in July 2024, asserting 11 more patents. The cases were consolidated a month later. Between April 2024 and January 2025, Micron filed 25 inter partes review (IPR) petitions and one post-grant review (PGR) petition challenging the validity of YMTC’s asserted patents. The District Court therefore stayed the case pending the IPRs, finding the IPRs “will likely simplify infringement, validity, and claim construction issues”. In June 2025, YMTC brought another complaint in the District of Columbia, this time accusing Micron of astroturfing in its campaign that led to YMTC’s exclusion from the U.S. market.
• In October, YMTC expanded its campaign overseas, filing suits in the High Court of Justice for England & Wales (October 7, 2025 ip fray article) and the UPC’s Dusseldorf Local Division (LD). The patents asserted in the latter include EP3909047 (“Double data rate circuit and data generation method implementing precise duty cycle control”) and EP3850660 (“Three-dimensional memory devices having through stair contacts and methods for forming the same”). Both UPC cases are still in the written phase.