Yangtze Memory Technologies
Yangtze Memory Technologies Corp (YMTC) is a Chinese semiconductor integrated device manufacturer specializing in flash memory (NAND) chips. Founded in Wuhan, China in 2016, the company received backing from Tsinghua Unigroup. Its consumer products are marketed under the brand Zhitai. As of 2020, YMTC is using a 20nm process to make 64-layer 3D NAND flash. In April 2020, the company unveiled its first 128 layers vertical NAND chip based on XTacking architecture, which has since entered production. History. Tsinghua Unigroup founded YMTC in July 2016, together with Hubei provincial government and the Chinese national "Big  Fund" China Integrated Circuit Industry Investment Fund with a total investment of $24 billion. In 2018, YMTC released its XTacking architecture designed for Vertical NAND chips at the Flash Memory Summit, receiving the "Best of Show" award. Xtracking enables YMTC to manufacture the memory and the logic circuits on separate wafers and connect them using plasma activation and thermal annealing. According to YMTC, this enables a higher speed for the production process and increases NAND performance. YMTC's 3D NAND flash memory chips were the first to be domestically mass-produced in China. Later in 2018, YMTC announced mass  production of its 32-layer 3D NAND flash memory chip, and in September 2019, YMTC reported that it had started mass-producing its 64-layer TLC 3D NAND flash memory chip, with both chips using its Xtacking architecture. In April 2020, YMTC announced that it had developed a 128-layer 1.33 Tb flash memory chip. In September 2020, YMTC unveiled its first consumer line products under the brand name Zhitai. Products include SATA and M2 SSDs based on its 64 layers Xtracking NAND chips. From 2020 to 2021, YMTC suffered from unsatisfactory yield from its initial risk production of the  128-layer memory chip, averaging around 30 to 40 percent. In September 2021, the company's chief operating officer announced YMTC had shipped over 300 million 64-layer flash chips, and its 128-layer QLC memory chip is ready for volume production. As of 2021, YMTC was planning its second fab with a capacity of 100,000 wafers per month which will double its total output to 200,000 wpm. News agencies reported in January 2022 that YMTC has scrapped its intention to build a second 3D NAND fab announced in 2017, citing serious financial issues at Tsinghua Unigroup, its parent firm . Bloomberg reported in March 2022 that Apple is exploring purchasing NAND chips from YMTC to diversify its NAND chip vendors. Controversies. In July 2021, U.S. Representatives Michael McCaul and Bill Hagerty wrote a letter to the U.S. Secretary of Commerce arguing that YMTC should be placed on the department's Entity List. The letter stated that YMTC will assist the Chinese government in using unfair trade tactics to force American competitors out of the memory-chip sector, thereby putting US national security at jeopardy. It also highlights YMTC's alleged close ties with the Chinese Communist Party and Chinese military , as some YMTC executives previously worked for Semiconductor Manufacturing International Corporation, which was added to the Entity List in December 2020. In April 2022, U.S. Senator Marco Rubio voiced his displeasure with reports that Apple was considering procuring NAND chips from YMTC. YMTC, according to Rubio, has ties to the Chinese Communist Party and the People's Liberation Army.