SK Hynix's Yongin Timetable Is Now the Memory Market's Timetable

SK Hynix has put dates on the next stage of its giant chip complex in Yongin, south of Seoul, and those dates now set the pace for how much high-bandwidth memory the world's AI build-out can count on later this decade.

On Aug. 7 the company said it would build the second of four planned fabs at the Yongin Semiconductor Cluster, known as Y2, along with a new NAND plant, M17, in Cheongju. Together the two projects represent about 54 trillion won of investment. The decision, SK Hynix said, executes a master plan to invest 600 trillion won in Yongin and 100 trillion won to expand its Cheongju base.

The schedule is specific. Construction of the first Yongin fab, Y1, is under way, with its first cleanroom targeted to open in February 2027. Y2, a DRAM plant with about 1.13 million square meters of floor area, is scheduled to break ground in July 2027 and open its first cleanroom in June 2029, producing high-bandwidth memory and other advanced DRAM. M17 in Cheongju is to break ground in February 2027 and open its first cleanroom in December 2028.

Those dates matter because high-bandwidth memory, or HBM, has become one of the tightest inputs in AI hardware. Every large AI accelerator carries stacks of it. Capacity that opens in 2029 is capacity that customers planning AI systems for 2029 and 2030 are already trying to secure.

The company explained its choice of Cheongju for NAND by speed. The site already houses the M11, M12 and M15 fabs with power and water infrastructure in place, which SK Hynix said gives it "the fastest fab construction timeline."

Yongin is a different proposition. It is a greenfield complex that needs new power, water and road connections. In July 2023 the government designated Yongin-Pyeongtaek a national high-tech strategic industry specialized complex, a status that comes with faster permitting, tax and budget support, and help with infrastructure including power and water.

The risk for investors is in the gap between master plan and execution. A 600 trillion won commitment spread across four fabs and two decades will be paced by demand, by the availability of power and water, and by construction capacity. A cleanroom opening is also only the start of a ramp: tools must be installed and qualified, and HBM yields must be brought up before meaningful output reaches customers.

The markers to watch are concrete. The first is whether Y1's cleanroom opens on schedule in February 2027. The second is whether Y2 breaks ground in July 2027 as planned. Updates on power and water connections to the cluster will show whether the infrastructure keeps pace with the fabs.

If those dates are met, SK Hynix will have a clear path to adding memory capacity at the end of the decade. If they slip, so does the supply the AI industry is counting on.