Samsung bets 46 trillion won on Onyang HBM hub as Cheonan hits its limit

Samsung Electronics kicked off construction on November 12, 2026, turning its Onyang campus in Asan into a second major production base for advanced AI memory. The build-out covers five high-bandwidth memory packaging lines, backed by 46 trillion won — roughly $34 billion — aimed at expanding back-end capacity.

The trigger is a space problem, not a strategy deck. Cheonan, where much of Samsung's HBM packaging happens today, is out of room, and the squeeze has already forced the company to shuffle equipment and outsource some of its conventional memory module work. Onyang is no blank slate: the site has been assembling and testing conventional semiconductors since 1991.

Line 5 alone is expected to lift cleanroom space at the site to approximately 31,000 square meters. Campus floor space currently stands at 270,000 square meters; the project pushes that to 420,000, roughly 55% more room. Operations are slated to start in June 2028 — a year earlier than previously expected.

Onyang is the biggest slice of a larger regional push. Samsung has announced a total investment of 60 trillion won for its Chungcheong semiconductor initiative, which also covers upgrades at Cheonan, and the program lines up with a South Korean government effort called the “Three Great Leap Mega Projects.”

The timing tracks the shortage. HBM for AI servers has stayed persistently tight, with shortages projected through 2028, and reports indicate customer demand is outpacing contract supply into that same year. The new lines are built to close exactly that gap.

Markers to watch: progress on Line 5, whether the June 2028 operational target holds, and how much of Cheonan's outsourced conventional work stays outsourced once Onyang is running. The rest of the 60 trillion won Chungcheong plan, particularly the Cheonan upgrades, will decide how much advanced AI memory Samsung can actually ship later this decade.