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Micron files plan for Boise expansion: would rival the Pentagon in size, with manufacturing, offices, gas plant, parking, more


Micron Technology has filed the first set of permits for the planned large-scale expansion of its Boise headquarters. The plan includes a dizzying array of new buildings and features to support its plan to bring the manufacturing of semiconductors back to the US.

In all, the plan would add more than 6.5 million square feet of space to the site – about the size of the Pentagon.

To get there, Micron will need a number of permits. To start, it will need to annex additional land it owns into Boise City Limits. The land is on what the city calls the Columbia Bench – the area south of Idaho 21 and roughly north of Interstate 84 in southeast Boise. Micron also hopes the city will give it the approval to change the zoning on a sliver of land.

What’s planned

Site plan for proposed Micron campus expansion. Via Micron

The fab

A conditional use permit application for the campus expansion details a significant number of new buildings or an expansion of existing buildings.

The largest, by far, is the planned new “fab” – short for fabrication plant. The building will go up four stories and include 4.85 million square feet of space. At 160 feet in height, it would be about as tall as the Idaho Power building downtown.

Though there’s not a reliable source of record-keeping, it’s likely this would be the largest building in the State of Idaho. The Amazon distribution center in Nampa, for instance, is roughly half as large at 2.65 million square feet. The Amazon Nampa building takes up about 650,000 square feet on the ground floor, whereas the Micron fab is 1.2 million for the first floor alone.

“The size, scale, and complexity of the fab requires many new employees and support facilities to function,” Micron Facilities Architect Paul Marcolina wrote in an application letter. “In support of the fab we will be adding office, manufacturing, administration, and utility facilities.”

The building will include 600,000 square feet of cleanroom space – an area controlled for a low amount of airborne particles used in developing and producing semiconductors.

During a ceremonial groundbreaking last month, Micron said the Boise cleanroom would be the largest in the US. However, it later said it would build 2.4 million square feet of cleanroom space in a separate expansion in New York.

Support buildings

Administration building

While the fab is the star of the show, the rest of the expansion adds significant new facilities to the already extensive Boise campus.

A new administration building would parallel Federal Way and sit near the fab. The plan calls for a large podium-style parking garage on the lower levels, with room for 3,600 cars. For comparison, the Capital City Development Corp. operates six public parking garages in Downtown Boise, which, taken together only include 3,179 parking spaces.

Beyond the significant parking, the building will have office space, plus a wellness center and fitness center. It will include 440,000 square feet of space.

This building is separate from a project BoiseDev told you about in August to build a new “world-class” office building elsewhere on the campus.

Probe building

Running parallel to the admin building, and connected by a courtyard, is a structure Micron calls the Probe building. It will be 365,000 square feet in size, and also connects to the FB, as well as another building nearby via a sky bridge.

“The upper floor of the probe building is predominately clean room space (approximately 85,000 square feet) where the final stage of the wafer manufacturing process, functionality testing, is completed,” Marcolina wrote.

On the lower floors of the probe building, Micron plans additional office space, a cafeteria, and other uses.

Building B51X

A current fabrication building, which Micron calls B51, will add 92,000 square feet of space.

“We will be expanding our existing TD wafer manufacturing facility to include an Automated Material Handling System that will automatically transfer wafers produced onsite to the probe facility for testing and ultimately to the FAB for fabrication of microchips,” Marcolina wrote.

This building expansion will connect to the Probe facility, and, ultimately the new fab itself.

Central utility building

Just to the north of the fab, Micron will build a new central utility building. At 450,000 square feet, it will include support systems the company says will help operate the fab, and “power the manufacturing and fabrication processes such as boilers and chillers.”

Mask manufacturing building

An existing manufacturing facility for masks – or “reticles,” will also see expansion with another 30,000 square feet.

But wait, there’s more…

The project also includes several production support buildings, a construction warehouse, vendor building and more. It also includes several elements for support from utilities.

Gas plant

A large new gas plant will be built, and the City of Boise will need to sign off on a height exemption for a tall new structure.

“Semiconductor manufacturing requires high-purity gasses,” Marcolina wrote. “The gas plant will use two gas columns and cold rooms to separate out gasses like oxygen and nitrogen from ambient air to be used in the FAB. For the gas plant to function, the columns need to be approximately 185’ in height.”

The columns will be roughly as tall as the Wells Fargo building in Downtown Boise.

The gas plant sits on the far eastern edge of the campus expansion

Water treatment facility

Micron says it will operate its own onsite water treatment plant.

“This state-of-the-art water treatment facility will have multiple functions,” Marcolina wrote. “t will treat incoming water to ensure it meets our high-purity specifications for manufacturing use in the FAB, and it will serve as a wastewater treatment facility.”

Marcolina’s letter said they will use both water from the municipal water system operated by Veolia, as well “on-site groundwater sources.”

“Water conservation and reuse are paramount and Micron plans to treat and reuse the majority of our wastewater on-site,” he wrote. “Any excess wastewater will be fully treated before being discharged to City’s treatment facility.”

Electrical yard

A 22-acre portion of the campus will be converted for use as an electrical yard. Micron says the facility will act as a substation and will help support power needs for the fab. The company said the equipment will be operated by Idaho Power.

What’s next

The Micron expansion will need approval for a conditional use permit, as well as annexation and rezoning. Hearing dates for the approvals have not yet been set.

Micron has said the project will be built out between now and 2030.

Don Day - BoiseDev Editor & Founder
Don Day - BoiseDev Editor & Founder
Don is the founder and publisher of BoiseDev. He is a National Edward R. Murrow Award winner and a Stanford University John S. Knight Fellow. Contact him at [email protected].

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