Samsung is expected to ramp 64-layer NAND in H2 with a new plant coming on-stream in Pyeongtaek in July.

Micron is expected to be in volume production of 64-level 3D NAND in Q2.

Toshiba is producing 64-layer chips and Hynix says it has a 72-layer chip.

Yields, which were poor, have now improved and the general expectation for NAND is that supply constraints will ease in H2.