3D vertical NAND stacking architecture

Every solid-state drive, every smartphone, and every AI data centre depends on a memory technology that six countries can make and India cannot make at all. As of 2026, India imports 100% of its 3D NAND and advanced memory.

3D NAND stores data by stacking memory cells vertically rather than spreading them across a flat plane. To build it, manufacturers drill through alternating layers of silicon oxide and silicon nitride, forming channels that run down through the entire stack, then line them with a charge-trapping layer that holds each bit. Samsung mass-produced the world's first such structure in 2013 with its first-generation V-NAND. The roadmap since has been a race upward: imec projects stacks approaching 1,000 layers by 2030.

The difficulty scales with the height. Etching a channel that stays straight and uniform through six to ten microns of stacked material — an aspect ratio beyond 50:1 — sits at the edge of what plasma physics allows. Cryogenic etching, running the wafer at deep sub-zero temperatures, was developed specifically to keep those profiles clean at high layer counts; Lam Research's Cryo 3.0 system launched only in July 2024. Atomic layer etching, which removes material one atomic layer at a time, is what makes 200-plus-layer stacks feasible without damaging sidewalls. Wafer-to-wafer hybrid bonding, with alignment measured in fractions of a micron, lets makers place control logic directly beneath the memory array to maximise density.

India possesses none of this. It manufactures under 1% of the world's semiconductors and runs no indigenous 3D NAND production and no foundational R&D in the field. The market is held by Samsung (31%), SK Hynix (18%), Kioxia (17%), Western Digital/SanDisk (15%), Micron (11%), and China's YMTC (13%), whose Xtacking architecture reached 294 layers.

The gap is structural, and it lies in the tool chain. The etchers, bonders, and metrology systems that make 3D NAND come almost entirely from Lam Research, Tokyo Electron, Applied Materials, and EV Group. India expects to import over 90% of its chip-making equipment and 85–90% of its specialty chemicals and gases. Its first front-end fab, the Tata-PSMC facility at Dholera, targets mature 28–120nm logic nodes at 50,000 wafers a month by 2027 — not memory.

Closing the distance would mean more than a fab. It would mean building competence in high-aspect-ratio etch, atomic-scale profile control, and hybrid bonding — the deep processes beneath the architecture, each a mountain of its own. That climb has not yet begun.