What’s Striking About Wolfspeed’s New Silicon Carbide Fab In Marcy, New York

I recently had the opportunity to visit Wolfspeed’s new silicon carbide (SiC) semiconductor fab in Marcy, New York. I’m a big fan of SiC, and with conventional silicon devices reaching their limits, SiC power semiconductors will play an increasingly critical role in future electric vehicles and anything that handles electrical power. The fab looks very different than ones that makes logic chips. Nonetheless to one who has visited many fabs around the world, there are two things that make this one striking: the use of automation, and the support the company received from the State of New York.

The site sits on top of a hill and includes a 500,000 ft² building on four levels with a 120,000 ft² class 100 cleanroom for device production, and an additional 10,000 ft² space dedicated to backend processes like material grinding and bonding. This fab will produce SiC MOSFET devices on 200 mm diameter (eight inch) wafers, which is a step up from the 150 mm or smaller sizes that historically have been used. A 200 mm wafer holds 1.78 times as many chips as 150 mm, and this combined with tool investments will make Marcy the world’s largest and most productive SiC device fab.

SiC is a very difficult material to work with, and you have to do things like grow epitaxial layers, bake things, and construct features using ion implantation. The company also grinds the chips during fabrication, which is challenging because SiC is one of the hardest materials in the world. That means you have to grind with the hardest substance – diamond, which is a messy process. As predecessor company Cree (the company changed its name to Wolfspeed last year), it was a pioneer in device design and manufacturing process innovations, which led to smaller chips for a given power rating, which meant more chips per wafer and higher device yields.

Logic chip manufacturers like IntelINTC
, TSMC, and nearby GlobalFoundries in Malta, NY switched to 300 mm wafers long ago because of the need for much higher chip volumes. They all use extensive automation, moving batches of wafers around in FOUPs (front opening unified pods) with overhead transport systems that move them between individual tools on the floor of the fab in the sequence dictated by the chip recipe. But nobody yet had gone back and done the automation work to enable 200 mm. Here the Marcy fab is the pioneer. The Wolfspeed team adapted some of the tools used for 300 mm, such as the overhead transport system, and worked with tool manufacturers to develop automated load ports. They will be using SMIF (for Standard Mechanical Interface) pods that are more or less standard for 200 mm to transport the wafers.

This will be a “lights out” fab, which means even though there will ultimately be around 600 people working at the site, there won’t be any operators in the clean room – just the occasional technicians to maintain the tools and robotics. This should have a positive impact on yield, as humans moving around a cleanroom are a major source of particle contamination and consequent yield loss. It also means that even when there is a major winter snowstorm (that part of upstate New York can receive lots of snow), production can keep humming along.

That brings me to the second striking thing about this fab. It has the feel of an industrial development project in Asia. The site is in the Marcy Nanocenter, on top of a forested hill adjacent to the SUNY Polytechnic Institute, just off the New York State Thruway. New York State had been developing the site for some time, and Adam Milton, VP of the Mohawk Valley Fab and my host for the visit told me it was “shovel ready, plug-and play … water, drains, sewers, power, all the things you need to build a high volume scalable semiconductor factory were already here.” The site spans 434 acres and Wolfspeed occupies 55 of them, so there is room for more companies to come in. The state also helped to expedite permitting approvals and anything else the company needed.

The ability to hire a workforce is essential for a complex manufacturing operation like Marcy. “SUNY Poly already had pretty strong electrical engineering technology and mechanical engineering technology programs,” Milton explained. “That very much aligned with what we needed in terms of process engineers, device engineers, or industrial and mechanical engineers.” Also, during the construction of the fab, Wolfspeed sent a team of its engineers to the College of Nanoscale Engineering (CNSE) in Albany. As part of the New York State incentive package, CNSE provided cleanroom space and engineering support for the company to first transfer a 150 mm pilot process from its facility in North Carolina, and then set up a full flow 200 mm pilot line. “That kind of prototyping is absolutely essential,” Milton added. “Because you really want to do that before you scale up. We were able to demonstrate yields and reliability out of that facility, and that saves a lot of time.”

In nearby Utica, NY, the company established a partnership with Mohawk Valley Community College (MVCC) to help develop technicians. MVCC developed a curriculum aligned with company needs. “We can send them there for a six week course or a one quarter long course to get that supplemental training they need,” Milton added. MVCC also had a lab space in downtown Utica where Milton’s team was able to set up an entire prototype automation line with all the software and hardware infrastructure that they planned to use in Marcy. “As this building was completed, we could basically take that automation work that was already done in the lab in Utica and plug it in place right here into this building,” explained Milton. “That was another huge feather in our cap to really hit the ground running with the startup for this factory.” By his estimate, all of these things took a year off the time to build, equip, and get the fab running.

Construction of the Marcy fab is complete and all of the tools have been moved in. It is in the qualification phase right now, and customer shipments are planned before yearend. The whole approach, and more importantly the speed made it feel like an industrial development project in Taiwan, or maybe South Carolina.

Wolfspeed’s new fab will establish Marcy, New York as a major supply link in the energy transition. It could also be a model for how to do industrial development.