SK Hynix 321 Layer NAND

Hynix has started mass production of the world’s first 321-layer NAND – a triple level cell-based 4D memory with 1Tb capacity.

Following its launch of a  238-layer NAND in June last year, Hynix has become the world’s first supplier of tNAND with over 300 layers by finding a technological breakthrough for stacking.

The 321-layer device offers a 12% improvement write time and a  13% improvement in read time. Compared to the 238-layer device.

The company plans to provide the 321-layer 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.

The process  connects three plugs through an optimised follow-up process after three times of plug processes are finished. For the process, 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.