Micron plans $9.6 billion HBM fab in Japan as AI memory race accelerates
U.S. chipmaker set to expand Hiroshima site with heavy support from Tokyo.
Micron is preparing a major expansion of its Hiroshima operations to build a dedicated high-bandwidth memory (HBM) facility, according to a report by Nikkei Asia. The report says the company intends to invest 1.5 trillion yen — US$9.6 billion — in a new plant on its existing site, with construction scheduled to begin in May next year. Shipments would follow around 2028. Japan’s Ministry of Economy, Trade and Industry (METI) is expected to contribute up to 500 billion yen in subsidies to support the project, though neither Micron nor METI has confirmed the report.
HBM has arguably become the most constrained component in the AI supply chain, giving the project some real weight in terms of government subsidies. SK hynix currently leads the market and has committed most of its HBM, DRAM and NAND output to Nvidia through 2026. Samsung is working to catch up with its 12-layer HBM3E stacks, while Micron has pushed hard to grow its own presence through HBM3E supply deals with Nvidia and AMD. TrendForce data shows Micron moving toward roughly a quarter of the HBM market with 20% of shipments as production increases; a dedicated Hiroshima expansion could shift that balance further once it comes online.
Japan has been aggressive in courting this kind of investment, offering substantial government incentives to foreign chipmakers as part of a wider effort to rebuild domestic semiconductor capacity. TSMC’s Kumamoto fabs and the state-backed Rapidus project are already part of this strategy.
Micron itself has been a significant beneficiary. Last year, Micron announced plans to introduce EUV-based DRAM production on the same Hiroshima campus, investing 500 billion yen of its own cash and supported by nearly 200 billion yen in subsidies. The first LPDDR5X memory devices produced on its 1γ process at this facility then began sampling in May of this year.
The scale of the planned plant aligns with expectations for the next generation of AI accelerators. Nvidia and AMD are both shifting towards HBM4 and HBM4E, both of which require tighter process control and higher layer counts. Capacity has been thin throughout the current GPU cycle, with long lead times and allocation limits driven by the mismatch between demand and available wafer starts. If Micron’s new plant reaches volume production in 2028, it will arrive just as those next-generation GPUs are.
For Micron, Hiroshima offers political and financial stability at a moment when both geopolitics and the market cause increasing uncertainty, and Tokyo’s willingness to fund a third of the project removes some of the risk from a multiyear build. The long runway to 2028 also gives Micron a clear path to expand its role
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Luke James is a freelance writer and journalist. Although his background is in legal, he has a personal interest in all things tech, especially hardware and microelectronics, and anything regulatory.