Core Viewpoint - Yangtze Memory Technologies Co. (YMTC) has initiated a challenge against Micron Technology's patents in China, marking a significant development in the ongoing global patent disputes between the two companies [1]. Group 1: Patent Challenges - YMTC has filed for invalidation of three Micron patents related to 3D memory technology with the National Intellectual Property Administration of China [1]. - The patents challenged by YMTC include: a memory array with vertically adjacent semiconductor structures, a three-dimensional memory and its formation method, and charge storage devices, systems, and methods [1]. - Micron has also initiated invalidation challenges against at least eight of YMTC's patents in China, which are currently under review by the Chinese patent office [1]. Group 2: Regulatory Scrutiny - The United States Patent and Trademark Office (USPTO) is conducting a "national security review" of YMTC's requests for patent invalidation against Micron in the U.S. [1]. - On November 10, the USPTO requested YMTC to provide justification for its IPR applications despite being on the Entity List [1]. - The timing of YMTC's challenges in China occurred in late September and October, prior to the U.S. national security review, indicating no direct connection between the two events [1].