Chinese 3D NAND champion YMTC has filed a lawsuit against Micron in the Northern District of California (via Blocks & Files) accusing the American company of infringing 11 of its patents covering various aspects of 3D NAND operation. Yangtze Memory asks the court to order Micron to stop the stop the sale of Micron's memory in the U.S. while awarding it with royalty fees.
YMTC says that Micron's 3D NAND memory with 96 layers (B27A), 128 layers (B37R), 176 layers (B47R), and 232 layers (B58R) as well as some of Micron's DDR5 SDRAM products (Y2BM-series) infringe 11 of its patents or patents applications filed in the U.S. The list of patent applications gathered by @lithos_graphein indicates that they cover general aspects of 3D NAND and DRAM functionality, which may essentially mean that YMTC is trying to make Micron's life harder in a get to gain a leverage against the U.S. government.
The U.S. Department of Commerce blacklisted YMTC in late 2022, which made it considerably harder for the company to obtain advanced fab equipment from American companies to build its market-leading 3D NAND devices. Last year the company faced even larger problems when the DoC barred sales of fab tools and technologies that could be used to build 3D NAND with more than 128 active layers, which was another blow for the company.
But Yangtze Memory has managed to persuade Chinese Cybersecurity Review Office to ban the use of Micron's memory in PCs used by government agencies as well as local governments.
Despite severe restrictions set by the U.S. government, YMTC continued to evolve its 3D NAND memory. The company's Xtacking 3.0 flash memory is in mass production (and some of such devices even do not infringe U.S. sanctions) and now the company is working on 3D NAND featuring its Xtacking 4.0 architecture. Also, earlier this year the company said that it had managed to dramatically improve endurance of 3D QLC NAND to a level of 3D TLC NAND (to 4,000 program/erase cycles), which significantly improves characteristics of inexpensive SSDs.
Interestingly, U.S.-based Patriot Memory is prepping a high-end PCIe Gen5 x4 SSD with an up to 14 GB/s read speed based on a controller from Maxiotek (a China-based company that evolved from JMicron) and 3D NAND memory from YMTC.
