Yangtze Memory Technologies
Yangtze Memory Technologies Corp (YMTC) is a Chinese memory semiconductor manufacturer of dynamic random-access memory (DRAM) chips and flash memory 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 will enter mass production by late 2020 to early 2021.

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.

News agencies reported in January 2022 that YMTC has scrapped its intention to build a $24 billion 3D NAND fab announced in 2017, citing serious financial issues at Tsinghua Unigroup, its parent firm.

References 

Computer hardware companies
Computer memory companies
Consumer electronics brands
Computer storage companies
Semiconductor companies of China
Chinese companies established in 2016