On August 23rd, semiconductor research firm SemiAnalysis released a series of posts on the X platform detailing the technical rationale behind the industry's transition from tungsten to molybdenum in 3D NAND flash memory production.

3D NAND stopped scaling laterally roughly a decade ago, pivoting instead to vertical stacking to boost storage density. However, as layer counts breach the ~300-layer threshold, the tungsten word lines connecting each memory cell have hit physical limitations: excessive resistance, fluorine-based chemical processes causing current leakage, and an inability to achieve effective filling in ultra-deep holes.

SemiAnalysis stated in its posts: "Molybdenum isn't an optimization; it's a requirement for NAND above 300 layers."

Compared with tungsten, molybdenum offers three key advantages: lower resistance for faster read/write speeds, no reliance on fluorine-based chemistry, and superior gap-fill capability in high-aspect-ratio structures. These three benefits directly counter the three core defects tungsten exhibits in deep stacking, making the material substitution a technical necessity rather than an optional engineering refinement.

Current Industry Landscape: Mass Production in the 2xx Layer Range, Inflection Point Reached

SemiAnalysis mapped out where each major manufacturer currently stands on layer counts: Kioxia/SanDisk at 218 layers, Micron at 276 layers, Samsung at 286 layers, and SK Hynix leading the pack at 321 layers.

The jump to the 3xx-to-4xx layer range is now underway. SemiAnalysis estimates that molybdenum's share of total NAND production capacity will climb from a mid-single-digit percentage in 2025 to approximately 30% by 2027.

All Three Major Players Committing Fully

The primary NAND manufacturers have all made clear commitments to transitioning to molybdenum-based processes, with well-defined timelines:

Samsung is the first mover, having already entered mass production with molybdenum word lines since 2024.

Micron kicked off high-volume manufacturing on Lam Research's ALTUS Halo equipment in 2025.

SK Hynix plans to introduce 375-layer NAND using molybdenum technology by the end of 2026.

Equipment Vendors: A New Market Exceeding US$1 Billion

Each tungsten-to-molybdenum conversion requires new deposition equipment. SemiAnalysis projects that NAND molybdenum deposition equipment sales will surpass US$1 billion in 2027 alone, growing to approximately US$2 billion annually by 2030 as DRAM and logic chips follow suit.

In terms of beneficiaries, Lam Research stands to gain first, with TEL (Tokyo Electron) close behind; AMAT (Applied Materials), ASMI, and Chinese equipment maker Naura (Beijing NAURA) are positioned to benefit more from the subsequent transition wave in DRAM and logic manufacturing. SemiAnalysis noted that full segment-level calculations have been incorporated into its front-end equipment (WFE) model.