Amkor to add 60,000 square metres of cleanroom in $12 billion Arizona buildout

Amkor Technology, a major outsourced chip-assembly and test (OSAT) contractor, is lifting planned investment in its Arizona advanced-packaging campus to about USD 12 billion, the company announced on September 9, 2026.

Phase 2 adds 60,000 square metres of cleanroom to a site that will total about 93,000 square metres once complete. Construction is expected to begin in late 2027 and finish by the end of 2029, with combined employment across both phases set to exceed 3,500 Arizona-based jobs.

Phase 2 is being driven by oversubscribed customer demand. Amkor sized Phase 1 for 33,000 square metres of cleanroom, and customer commitments for that footprint already outran capacity, the company said. The additional 60,000 square metres are being added because private orders did, not because federal incentives did.

Amkor describes the site as the first OSAT production site in the United States for advanced packaging at high volume, with wafer bump, probe, assembly, and test capabilities. OSAT contractors package and test finished silicon for chipmakers; they do not fabricate wafers.

Phase 2 cost figures, final cleanroom yield, and the names of anchor customers have not been disclosed.