SemiAnalysis: Flash memory manufacturing is “switching from tungsten to molybdenum”

On August 23, semiconductor industry research firm SemiAnalysis published a series of posts on platform X, outlining the technical rationale for the transition in 3D NAND flash production from tungsten (W) to molybdenum (Mo).

3D NAND stopped lateral shrinking about a decade ago, instead achieving increased storage density through more vertical stack layers. However, once the number of layers surpassed around 300, the tungsten word lines connecting each memory cell encountered a physical bottleneck: excessive resistance, fluorine-based chemical processes causing leakage, and ineffective filling in ultra-deep holes.

SemiAnalysis stated in the posts: “Molybdenum is not an optimization; it is the only option for NAND above 300 layers.”

Compared to tungsten, molybdenum offers three key advantages: lower resistance (resulting in faster read/write speeds), no need for fluorine-based chemicals, and better fill capability in high aspect ratio structures. These three strengths directly address the core shortcomings exposed by tungsten in deep stacking scenarios, making material replacement a technical necessity rather than just an optional engineering upgrade.

Industry status: mass production still at 2xx layers, turning point ahead

SemiAnalysis outlined the layer counts of major manufacturers: Kioxia/SanDisk at 218 layers, Micron at 276 layers, Samsung at 286 layers, and SK Hynix leading the industry with 321 layers.

The leap to the 3xx to 4xx layer range is now underway. SemiAnalysis estimates molybdenum’s share of total NAND capacity will rise from the mid-single digits in 2025 to approximately 30% by 2027.

Three major players fully commit

All major NAND manufacturers have committed to the transition to molybdenum processes, with clear timelines:

Samsung is the pioneer, with molybdenum word line products entering mass production in 2024.

Micron will launch mass production in 2025 using ALTUS Halo equipment from Lam Research.

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

Equipment suppliers: new market exceeds $1 billion

Every transition from tungsten to molybdenum requires new deposition equipment. SemiAnalysis estimates that in 2027 alone, sales of NAND molybdenum deposition equipment will exceed $1 billion, rising to about $2 billion per year by 2030 as DRAM and logic chips adopt the technology.

Regarding beneficiaries, Lam Research will benefit first, followed by TEL (Tokyo Electron); AMAT (Applied Materials), ASMI, and the Chinese equipment maker Naura will benefit more from the subsequent DRAM and logic chip transformation wave. SemiAnalysis notes that comprehensive market segment calculations are already included in its frontend equipment (WFE) model.