With a black marker and a bit of construction dust in the air, Phoenix Mayor Kate Gallego joined crews Wednesday to sign and help place the final steel beam on TSMC’s third fabrication plant in north Phoenix. The topping‑out ceremony pushes the massive project past its structural phase and into the nitty‑gritty of tool installation and hiring, a step city leaders say cements Phoenix’s role in a rapidly expanding semiconductor hub that could remake the North Valley economy.
In a post on X, Gallego said crews "placed the final beam on TSMC’s Fab 3" and that she was "honored to add my signature to this milestone," while thanking the "skilled women and men building it." The mayor tagged key TSMC Arizona and construction figures, including Rose Castanares and Ray Chuang. Mayor Kate Gallego’s post on X also features photos from the ceremony.
Where Fab 3 fits in the campus
TSMC’s north Phoenix complex is being built in stages and is slated to hold multiple fabs, advanced packaging facilities and R&D support buildings as part of the company’s multibillion‑dollar U.S. buildout. Company filings and local coverage indicate the second fab has recently wrapped its structural work, while the third is now topped out as crews pivot toward equipment move‑ins. For more background on the broader expansion, see reporting on how TSMC’s second chip plant hits finish line along with TSMC’s filing with the U.S. Securities and Exchange Commission.
Local stakes: jobs, water and roads
Officials have highlighted the campus as a major jobs engine. Company leaders have told reporters that a full three‑fab buildout could support thousands of direct positions, on the order of 6,000 roles by TSMC’s own estimates, according to Axios Phoenix. On the infrastructure side, the company has broken ground on a 15‑acre industrial water‑reclamation plant that is expected to recycle roughly 85–90% of process water by around 2028, KJZZ reported. State and local transportation agencies, meanwhile, are fast‑tracking upgrades such as the Loop 303/I‑17 interchange project to cope with increased freight and commuter traffic tied to the site, as noted by the Phoenix Business Journal.
Wednesday’s beam‑signing might be ceremonial, but it also marks a practical turning point: the coming months shift to bringing in fab tools, scaling up training programs and turning a forest of steel and concrete into working clean rooms. TSMC Arizona’s leadership, including President Rose Castanares, who has spoken publicly about hiring and education partnerships, will be central to that transition, according to city and company accounts. ABC15 Phoenix has followed those leadership moves and workforce plans.
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