Give China a domestic source of flash memory at world-class density, and grow from about 8% to 15% of the global NAND market despite US export controls.
267-layer Xtacking 4.0 NAND in mass production; 14% of world NAND shipments in Q2 2026.
Updated 3 Jun 2026Checked 11 Oct0 updates this week
Hundreds of thin layers are deposited, then deep holes are etched through them; each layer around a hole becomes one storage cell.
The read/write circuits are made on a separate wafer with a logic process, then bonded on top, so neither step compromises the other.
Each cell holds 3 bits (TLC) or 4 bits (QLC) by storing finely graded amounts of charge, trading endurance for capacity.
| Spec | Xtacking 3D NAND | Xtacking 3.0 (232 layers) | Change |
|---|---|---|---|
| Active layers | 267R (reported) | 232 | ▲ 35 |
| QLC die capacity (X4-6080) | 2 TbR (reported) | — | —no comparable change |
| TLC die capacity (X4-9070) | 1 TbR (reported) | — | —no comparable change |
| Global NAND shipment share | 14% (Q2 2026)R (reported) | — | —no comparable change |
| I/O speed, Xtacking 3.0 chip | 2,400 MT/sR (reported) | — | —no comparable change |
R reported by the company
YMTC (Yangtze Memory)
3D NAND flash, Xtacking, SSDs
Yangtze Memory Technologies (YMTC) in Wuhan is China's only maker of 3D NAND flash, the memory in SSDs and phones. Partly state-owned and on the US Entity List since 2022, it is now the world's third-largest NAND supplier by shipments and is preparing a Shanghai listing.
