Innovators and educators: At Yale, cleanroom staff make research possible

Inside the Becton Engineering and Applied Science Center on Prospect Street, in a fifth-floor space known as the university cleanroom, researchers from across Yale build small devices like qubits and microchips, circuits to manipulate or detect light, and microfluidics that hold tiny amounts of liquid for biological sequencing. Inside this facility, an array of advanced machines enables each step of the process, from design and fabrication to replication and testing.

But perhaps what is not found in the lab is as important as what is.  It’s critical that the cleanroom be kept free of particles that might otherwise compromise the field-leading research being done here.

And it’s up to the cleanroom staff, a small team of technical and scientific experts, to make sure the facility remains clean, safe, and functional — and to enable researchers to turn their ideas into reality.

“I really think of them as part of our research team,” said Peter Rakich, an associate professor of applied physics in Yale’s School of Engineering & Applied Science, whose research team has benefitted from the expertise of the cleanroom staff.

“They’re innovators, helping us figure out how to make whatever crazy new thing we think up. They are collaborators and codevelopers of a lot of innovation strategies that we use to make new experiments possible or new technologies realizable.”

Since 2019, Yong Sun, a scientist with experience in micro-/nanofabrication, has been the cleanroom’s director. But it was years before that, as a postdoctoral researcher in the lab of professor Mark Reed, when he fell in love with the cleanroom.

“I remember Mark coming into a lab meeting one day and saying to me, ‘Congratulations! You use the cleanroom three times more than the rest of the group combined.’”

When Sun’s postdoc ended, he went on to manage the cleanroom at Princeton for four years before heading to Seattle to work for a startup. Two years and three patents later, Sun returned to the East Coast where he worked for a company whose product — Elionix electron beam lithography systems — gave him opportunities to visit various cleanrooms in the region. With that access, Sun began to develop a clear understanding on how to better run a cleanroom.

So when professsors Mark Reed and Hong Tang asked if he’d like to come back to Yale and run the university cleanroom, he was excited — and ready.

“Having started my career in university cleanrooms, they were always my ultimate goal,” said Sun.

Keep it clean

The chief concern of any cleanroom staff is preventing the accumulation of particulates, or microscopic-sized bits of matter. The researchers who use the cleanroom build very small devices with features often below a micrometer in size. At scales that small, a single dust particle can ruin a device.

The most common source of particulates is people, so everyone who uses the cleanroom has to be fully covered. The gowning procedure consists of donning shoe covers, hair nets, beard nets (when applicable), and gloves in one room. In a second room, researchers then put on boots, coveralls, hoods, and safety goggles. Only certain items can be brought into the cleanroom and must be wiped down first.

Maintenance consists of regular surface wipe downs and ensuring people aren’t compromising the cleanroom while working inside.

Electrical engineers and applied physicists make up the bulk of cleanroom users, but researchers in other departments, such as neurosurgery, energy sciences, biomedical engineering, materials science, and cell biology, use it as well, as do staff from local companies. In the past four years, nearly 200 people have worked in the cleanroom.

Lauren McCabe joined the team last year as a staff scientist with nearly a decade of cleanroom experience. After graduating from college with a major in physics and a minor in chemistry, McCabe worked in a government lab’s cleanroom.

“I fell in love with it,” she said. “But I wanted to get my Ph.D. in order to expand the types of roles I’d be able to take on.”

She was accepted to the University of Delaware, which was especially appealing as it had just opened a brand-new cleanroom of its own. McCabe was one of the first to use it and during her time there she gained a lot of experience both in the cleanroom and in equipment maintenance. Just as she was wrapping up her dissertation, a position at the Yale cleanroom opened.

Finding solutions, moving projects forward

For Sun and McCabe, a typical day involves the maintenance and care of the lab’s more than 30 pieces of equipment, including sophisticated optical lithography systems, etching and thin film deposition systems, metrology, and back-end processing systems. They also procure new tools constantly to expand the cleanroom capabilities and train all new users.

“We help researchers with whatever they need,” said McCabe, who oversees the metrology and deposition systems and also serves as the cleanroom safety officer.

This, Sun says, is the most rewarding part of the job.

“When someone comes to us and we’re able to help them find a solution and move their project forward, it feels pretty great,” he said.

Another key reason why Sun and McCabe are such valuable contributors is that they’re also educators, said Peter Rakich, whose research group in the Department of Applied Physics is focused on experimental nonlinear optics and spectroscopy.

“There’s a lot of knowledge you have to have to get this work right and they retain so much that would be lost without them,” he said. “And they teach our students, imparting a lot of skills that make our students incredibly highly sought after when they leave Yale.”

A new Physical Sciences and Engineering Building, which will be built on Science Hill in the coming years, will eventually house a much larger cleanroom, and Sun and McCabe will lead the enormous effort of moving everything in the current cleanroom to the new facility while expanding capabilities and staff.

“It’s exciting to be here at this particular moment while getting to do things I love every day,” said McCabe.

Sun agrees. Much like when he was a postdoc, he still spends more time in the cleanroom than most. (It’s true, McCabe says. “I see the sign-in logs!”)

Sun remembers when, as a young boy, he’d see his father, a carpenter, working in his own shop in a remote village of China’s Jiangxi Province.

“I would see him whistling, working on his own, and he seemed to really enjoy it. I feel the same way working in the cleanroom,” said Sun. “When I’m working on a project, time just flies.”