Polar Semiconductor Fab Expansion and Renovation, Bloomington, Minnesota

Polar Semiconductor’s Bloomington fab can’t stop for its own expansion. Mortenson is building new cleanrooms beside active production bays at the 1969-vintage campus while the plant keeps running around the clock, the core of a $525 million program Polar says will roughly double its output of power and sensor chips.

The job got fresh attention this week. On Nov. 3, Construction Owners profiled the work Mortenson describes on its own project page: phased MEP tie-ins across several buildings, temporary utility reroutes and tool moves timed so capacity comes online area by area. Polar was the first commercial fab to get a finalized CHIPS award, a $123 million package from the U.S. Commerce Department in September 2024, and Minnesota added about $75 million in state support.

Project Scope

The work touches nearly every building on the campus at 2800 E. Old Shakopee Road. Crews are building new cleanroom space next to fab areas that stay at full production, upgrading aging infrastructure and tying new systems into old ones without dropping a tool.

That last part is where the schedule lives. Mortenson set up temporary feeds for gas piping, deionized water, heating and chilled water, process water and electrical service while permanent systems went in, working with the mechanical and electrical trade partner and Polar’s facilities staff. Existing MEP had decades of add-ons, so the team had to sort live lines from dead ones before anything moved.

A new elevator needed a 25-foot-deep pit with active cleanrooms on three sides. Driving piles wasn’t an option because of vibration, so the team used a non-vibratory earth retention system. In the P1 building, where overhead clearance is tight, point cloud laser scans fed reroute plans. BWBR, the St. Paul architect that designed Polar’s earlier fab addition, worked with Mortenson on details such as hanging H-frame steel on the exterior face of the existing precast so crews didn’t have to work inside the plant.

Each production tool follows its own sequence: decommission, decontaminate, upgrade utilities, reinstall and check. Mortenson’s Advanced Manufacturing Group runs that through pull planning and weekly work plans with Polar.

Why It Matters

Most CHIPS money has gone to giant greenfield fabs. Polar is the other model: an older 200 mm plant making power, sensor and, increasingly, gallium nitride devices for automotive, industrial and defense buyers. It’s now majority U.S.-owned after a 2024 investment by Niobrara Capital and Prysm Capital, and it has signed foundry and technology deals with UMC, Nexperia and imec’s IC-Link.

For builders, the lesson is about risk. A brownfield fab expansion avoids a new site and a new utility plant, but it trades that for zero-tolerance shutdowns and MEP archaeology. Polar’s plan expects about 160 new jobs. Whether the plant hits its doubled output on time will say a lot about how many other legacy fabs try the same move.

Project Team & Details