https://www.techpowerup.com/329078/sk-hynix-starts-mass-production-of-worlds-first-321-high-nand
 
SK hynix Inc. announced today that it has started mass production of the world's first triple level cell-based 321-high 4D NAND Flash with 1 Tb capacity. Following its previous record as the industry's first provider of the world's highest 238-layer NAND since June last year, SK hynix has become the world's first supplier of the NAND with more than 300 layers by finding a technological breakthrough for stacking. The company plans to provide the 321-high products to customers from the first half of next year.

Stacking more than 300 layers came into reality as the company successfully adopted the "3 plugs" process technology. Known for its excellent production efficiency, the process electrically connects three plugs through an optimized follow-up process after three times of plug processes are finished. For the process, SK hynix developed a low-stress material, while introducing the technology that automatically corrects alignments among the plugs.
 
With the adoption of the same development platform from the 238-high NAND on the 321-high product, the company could also improve the productivity by 59%, compared with the previous generation, by minimizing any impacts from a process switch.

The latest product comes with an improvement of 12% in data transfer speed and 13% in reading performance, compared with the previous generation. It also enhances data reading power efficiency by more than 10%.

SK hynix plans to steadily expand the use of the 321-high products by providing them to the nascent AI applications, which require low power and high performance.

Jungdal Choi, Head of NAND Development at SK hynix, said that the latest development brings the company a step closer to the leadership of the AI storage market represented by SSD for AI data centers and on-device AI. "SK hynix is on track to advancing to the Full Stack AI Memory Provider by adding a perfect portfolio in the ultra-high performance NAND space on top of the DRAM business led by HBM."
 
A rather amazing achievement.