Original author: Ada, TechFlow
According to industry research firm TrendForce, SK Hynix has completed the design verification of its 375-layer NAND flash memory, with mass production scheduled to begin at the end of 2026. The company will convert existing production capacity for production. The completion of SK Hynix's 375-layer NAND verification brings to the forefront a long-awaited industry turning point: tungsten, used in chips for nearly a quarter of a century, is being replaced by molybdenum. The real winners of this material substitution are not memory manufacturers, but rather those upstream suppliers of equipment and consumables.
Tungsten has held up for nearly 25 years, and scaling is pushing its physical boundaries.
It's worth noting that Samsung, not SK Hynix, was the first to introduce molybdenum into metallic wiring. Samsung had already adopted molybdenum in its 286-layer 9th-generation NAND flash memory, which entered mass production in April 2024, and is currently expanding the use of molybdenum to more process steps. This is the first time SK Hynix has used molybdenum in its own product line, placing it in a catch-up rather than pioneering position in the industry.
This 375-layer product itself has a history of downward revisions. According to TheElec, Hynix originally aimed for a 400-layer product, but due to the manufacturing complexity of high-layer stacking, it was ultimately revised down to 375 layers. Even so, it is still a key leap in Hynix's NAND roadmap, as the more advanced 480-layer and 604-layer products are believed to rely more heavily on molybdenum.
While molybdenum's replacement of tungsten isn't unique to memory, it has brought about an industry-wide turning point. Tungsten has reportedly been used as an interconnect metal in NAND, DRAM, and logic/foundry mid-processes for nearly 25 years, but scaling requirements are now pushing the boundaries of tungsten, making molybdenum the most promising replacement candidate.
Molybdenum's advantages extend beyond low resistance. Unlike tungsten and copper, molybdenum can prevent diffusion without a barrier layer, eliminating processing steps and improving yield. Its high melting point and oxidation resistance support direct deposition, making it more suitable for high aspect ratio structures such as 3D NAND and GAA (gate all around) structures in logic. In other words, the higher the number of layers and the lower the node, the more difficult it is for tungsten, while the greater the potential for molybdenum to penetrate. This is the foundation of the "shovel seller" logic; once alternatives are widely adopted, those providing the tools and materials will benefit.
Lam Research: The only shovel seller that has already mass-produced ALD molybdenum tools.
The most direct and compelling narrative in this line is that of Lam Research (LRCX). Its ALTUS Halo, launched in February 2025, is touted by the company as the industry's first atomic layer deposition (ALD) tool to utilize molybdenum in mass production, offering over 50% improvement in resistance compared to traditional tungsten metallization in most cases. Lam disclosed that early adoption has already begun in high-capacity 3D NAND and advanced logic factories in South Korea and Singapore, with Samsung and SK Hynix in South Korea and Micron in Singapore.
Business flexibility lies in the increasing complexity of the process. According to Zacks research, Lam is currently the only supplier with ALD molybdenum tools in mass production, serving both foundry and NAND customers. Although molybdenum deposition is slower and more complex, it allows Lam to triple its single-wafer metal deposition service market (SAM) at these advanced nodes. Increased process complexity actually translates into growth for equipment manufacturers.
Entegris sells consumables; Micron is the only pure memory stock listed on the US stock market.
Applied Materials (AMAT) is taking a different approach. In February of this year, it launched the Spectral ALD system, replacing tungsten in current transistor contacts with molybdenum to reduce resistance at this critical connection between the transistor and the copper wiring network. It has already been adopted by several leading logic foundries. It's important to distinguish that Lam's molybdenum story focuses on NAND/DRAM word lines, while AMAT's focuses on 2nm GAA logic contacts. Their downstream applications differ, and they cannot be considered the same beneficiary logic.
A representative on the materials side is Entegris (ENTG). This company supplies molybdenum dichlorodioxide (MoO₂Cl₂), a solid-state precursor for molybdenum, specifically customized for DRAM and 3D NAND, and equipped with the ProE-Vap delivery system. The logic lies in the cascading effects of material switching. According to Entegris, the shift from copper and tungsten to molybdenum will affect multiple stages, including precursor selection, polishing pad design, polishing slurry formulation, etching materials, and filtration. The process is more dispersed, but permeates multiple steps.
As for the memory manufacturers themselves, neither Samsung nor SK Hynix are listed on the US stock market. Micron (MU) is the only pure memory stock on the US stock market, and it has secured a leading position in molybdenum. Lam quoted Mark Kiehlbauch, Micron's VP of NAND Development, as saying that molybdenum metallization has enabled Micron to achieve industry-leading I/O bandwidth and storage capacity in the latest generation of NAND products. However, Micron is "the one who uses molybdenum" rather than "the one who benefits from selling molybdenum." Its stock price is mainly driven by memory cycles and HBM, with molybdenum merely being a performance bonus.
Molybdenum miners benefit? Semiconductor demand is just a drop in the ocean.
In theory, molybdenum miners could be considered marginal beneficiaries of this narrative, with Freeport-McMoRan (FCX) in the US stock market representing a company that uses molybdenum as a byproduct of copper mining. However, the scale of molybdenum consumption in the semiconductor industry is extremely small. According to estimates from The Elec and industry sources, Samsung purchased approximately 4 tons of molybdenum last year and about 10 tons this year, while SK Hynix started with about 4 tons. The entire industry is projected to consume only around 80 tons by 2030. Compared to the global molybdenum market, which is primarily used in steel alloys and consumes hundreds of thousands of tons annually, semiconductor demand is negligible. Linking miners' stock prices to the NAND narrative is a flawed causal relationship.
This also defines the true scope of the "tungsten retreat, molybdenum advance" story. Hynix's 375-layer technology is just the starting point; the real scope spans three major categories: NAND, DRAM, and materials. In this metal replacement, the links that sell tools and consumables are more certain. Memory manufacturers using molybdenum are the beneficiaries of performance rather than valuation, while the metal side basically doesn't benefit.
Disclaimer: This article does not constitute any investment advice.
