Taiwan has formally launched Phase 3 of the Chiayi Science Park expansion, a buildout that reportedly anchors plans by TSMC to add five additional advanced packaging plants at the site, according to a report from finance.biggo.com.

The National Science and Technology Council (NSTC), which administers Taiwan's science parks, opened the third-phase expansion as demand for advanced packaging capacity — particularly TSMC's CoWoS family of chip-on-wafer-on-substrate processes used for AI accelerators — continues to outstrip supply across the industry. The report characterizes TSMC's five-plant plan at Chiayi as a reported roadmap rather than a confirmed capital commitment, and the company has not published capacity or investment figures for the site.

Chiayi entered TSMC's manufacturing map in 2024, when the company confirmed it would build advanced packaging facilities in the southern Taiwan park. The Phase 3 expansion now underway expands the land available for that buildout. TSMC already operates advanced packaging capacity at its Zhongke and Nanke campuses and in Chiayi's earlier phases, and it has added overseas packaging and testing capacity in Tongluo, Miaoli County, as well as in Osaka, Japan, through its JASM-adjacent operations and a planned facility announced with partners.

The commercial logic behind the Chiayi push is straightforward. Nvidia, AMD, and a growing roster of AI accelerator designers depend on CoWoS and related 2.5D packaging technologies to bond large compute dies to high-bandwidth memory stacks. Packaging, not front-end wafer capacity, has been the recurring bottleneck for AI chip shipments over the past two years, and TSMC has been racing to expand CoWoS output on its N5 and N3-class products that feed into those packaged modules.

The expansion also carries geopolitical weight. Taiwan's government has prioritized keeping advanced packaging onshore even as TSMC builds leading-edge fabs in Arizona and integrates its Innolux-acquired Chiayi site commitments. Advanced packaging capacity concentrated in central and southern Taiwan reinforces the island's position in the AI supply chain, a factor that shapes both government land allocation through the science park system and TSMC's site selection.

According to the finance.biggo.com report, the five additional plants would join existing and under-construction packaging facilities at Chiayi, though no timeline, investment value, or capacity figures were disclosed. TSMC typically does not comment on unannounced site plans, and the NSTC has not tied specific tenant commitments to the Phase 3 land release.

For equipment suppliers, each advanced packaging plant represents demand for bonding, testing, and substrate-handling tools from vendors such as Besi, ASMPT, and Kulicke & Soffa, which have all cited CoWoS-driven orders in recent earnings cycles. A five-plant program at a single park, if realized, would rank among the largest packaging site commitments TSMC has made in Taiwan.

The next concrete signals to watch are land-handover milestones from the NSTC, environmental review filings for individual plants, and any capacity disclosures in TSMC's quarterly earnings calls, which remain the authoritative source for confirmed packaging capacity and revenue figures.