America is trying to build the one chip factory step it never kept at home

Amkor is nearly tripling an Arizona plant that finishes chips after they leave the fab, a step mostly done overseas today. Construction does not start until late 2027.

8 September 2026 · 6 min read

What happened

Amkor Technology, a chip-packaging company most people have never heard of, said on September 8 that it is nearly tripling its advanced packaging campus in Arizona, raising total planned investment to approximately $12 billion. The new phase adds 60,000 square metres of cleanroom, bringing the site to about 93,000 square metres, up from the 33,000 planned for phase one. Construction on the new phase does not start until late 2027, and the campus is not expected to be finished until the end of 2029. Amkor's release is datelined Tempe, where the company is headquartered; Arizona reporting places the campus itself in Peoria.

Advanced packaging is the step after a chip is manufactured: taking the finished piece of silicon and sealing it into the casing and connections that let it plug into a phone, a laptop or a server. It sounds like an afterthought. It is not. Arizona public radio reports that Apple will be the first customer at this campus, packaging chips made nearby by TSMC, which is itself spending billions expanding in the same state. Amkor's own release names no customer. Amkor describes the site as the first US production facility doing this work at high volume for outside customers, a claim about its own plant rather than an independent finding.

Why it matters

The US has spent years and tens of billions of dollars getting companies like TSMC and Intel to build chip factories on American soil. But a finished chip that comes out of one of those factories still has to go somewhere else to be packaged before it can be sold. A worked example: if a chip is made in Arizona by TSMC but flies overseas for packaging before flying back to a server farm in Texas, every step of that trip adds time, shipping risk, and a border outside US control. Amkor's expansion is a bet that closing that gap is worth $12 billion and a three-year wait.

Amkor's own release says the expansion is driven by strong customer commitments that have already surpassed the 33,000 square metres planned for phase one, before this expansion was announced, which suggests whoever is buying this capacity wanted more of it built in the US despite the extra wait. Independent financial analysis notes the risk on the other side: Amkor must convert customer demand into sustained capacity utilization and profitability once the plant is built, and points to competing packaging technology from Intel and competing test capability from FormFactor as alternatives customers could choose instead.

What would change it

The plan depends on two things holding for three years: that AI and consumer-electronics chip demand stays high enough to fill 93,000 square metres of cleanroom, and that Amkor's finances can carry a $12 billion commitment through a construction window that does not even open until late 2027. If AI chip demand cools before 2029, or a competitor's packaging technology becomes clearly better or cheaper, this bet gets harder to justify.

What we do not know

Independent sources disagree on the starting point. One outlet says the campus was announced at $2 billion in 2023 and has now grown to $12 billion. Another reports the immediately prior total was $7 billion. Amkor's own release states no prior figure at all, only the new $12 billion total, so this desk cannot say which comparison is right or reconcile the two secondary accounts. We also do not know which customer contracts back the expansion beyond the phrase customer commitments, or what state or federal incentives, if any, are attached; none were named in the sources this desk could read.

What this changes for you

If you own an iPhone or any device with a US-designed chip, this specific plant changes nothing for at least three years, and even then only indirectly, in how well the supply chain survives a shipping disruption or a trade dispute somewhere else in the world. The immediate effect is local: more than 3,500 people are expected to work at the combined campus once it is built, in a part of Arizona that is already one of the most concentrated chip manufacturing regions in the country.

Sources

Everything above is written from these. Each line says what that document proves.

1. ir.amkor.com: Amkor's own release: confirms the $12bn total, the 60,000 and 93,000 square metre cleanroom figures, the more than 3,500 workforce, the late 2027 to end 2029 timeline, the customer-commitments framing and the first-in-the-US claim. Datelined Tempe; it names no customer and no prior total.
2. kjzz.org: Independent Arizona public radio: source for Apple as first customer, the TSMC connection, the Peoria location, that packaging is mostly done overseas, and the $2bn/2023 starting figure.
3. finance.yahoo.com: Independent Zacks Investment Research analysis: confirms phase-1 capacity was already exceeded by customer commitments, and names Intel and FormFactor as competitive risks.
4. ktar.com: Independent Arizona news: source for the separate $7bn prior-total figure, disclosed as an unresolved discrepancy rather than reconciled.