Micron Technology broke ground this week on a $9.3 billion expansion of its Hiroshima fabrication plant, committing the largest single capital outlay by a U.S. semiconductor firm in Japan since the 1990s. The investment adds lithography lines and clean-room square footage specifically for high-bandwidth memory and next-node DRAM, both categories where supply remains structurally short. Construction timelines place first wafer output in mid-2027, with volume ramp through 2028.

The facility sits inside Japan's southern semiconductor corridor, where the government has allocated ¥2 trillion in subsidies to onshore advanced chip production. Micron's expansion qualifies for roughly 15 percent of project cost in direct incentives under the Economic Security Promotion Act, a figure that does not include tax credits on capital equipment or accelerated depreciation schedules. The Hiroshima site already produces 1α-node DRAM; the new wings will house 1γ-node tooling and dedicated HBM3E packaging lines. Micron has not disclosed wafer-per-month targets, but facility blueprints reviewed by local planning boards suggest an additional 60,000 wafer starts monthly at full build.

The timing reflects a calculated bet on AI infrastructure demand persisting through the second half of the decade. HBM pricing has held above $800 per gigabyte since Q3 2024, a level that makes even high-capex expansions accretive within 24 months. Micron's two largest customers—both hyperscale cloud providers—have already pre-committed to offtake agreements covering roughly 40 percent of the Hiroshima expansion's first-year output, according to supply-chain trackers. That early lock-in insulates Micron from a near-term memory glut, but it also means the facility is unlikely to serve merchant markets before 2029. The company is effectively building a captive line with public subsidy.

Operators should watch three follow-on events. First, Samsung and SK Hynix will face pressure to announce offsetting capacity by Q3 2025; both have delayed capex decisions pending clarity on U.S. export controls, and Micron's move forces their hand. Second, Japanese equipment suppliers—Tokyo Electron, Screen Holdings—will report Hiroshima-related orders starting in Q2 2025, offering a read-through on actual build pace versus public schedules. Third, Micron's quarterly capex guidance through fiscal 2026 will clarify whether this is the anchor project or the first of multiple expansions. The company has hinted at a second Hiroshima phase, contingent on HBM attach rates in next-generation accelerators.

Micron's Hiroshima groundbreaking arrives eight months after TSMC's Kumamoto fab began pilot production, and four months after Intel committed to Magdeburg. The global memory market has not seen simultaneous greenfield builds of this scale since 2010. By 2028, Japan will account for 12 percent of global leading-edge memory capacity, up from 3 percent today.