Cleanroom protocol required course at VA Tech
02/01/2001
Funds designed to lure semiconductor fabs to region speed microfab construction
Sheila Galatowitsch
BLACKSBURG, VA — Most University cleanrooms target seniors and graduate-level students conducting advanced research. Virginia Tech (Blacksburg, VA), one of the top engineering schools in the country, plans to build such a cutting-edge facility this year. But few schools make working in a cleanroom a requirement for sophomores and juniors pursuing engineering and science majors.
In January, Virginia Tech opened doors on an 1,800-square-foot cleanroom that will educate 500 undergraduates each year and serve as a required lab for electrical engineering, computer engineering, materials science and physics majors. "There's nothing special about it as a cleanroom, but as an undergraduate teaching facility it is unprecedented," says Robert Hendricks, professor of electrical and computer engineering and materials science. The $750,000 investment represents "one of the most expensive undergrad teaching labs we have ever built."
In addition to teaching cleanroom protocols and semiconductor manufacturing processes, the cleanroom will serve as the foundation of the university's microelectronics engineering minor, which is still under development. "Our objective is to have one of the top microelectronics programs by 2010," says Hendricks. To achieve that, Virginia Tech must capture students' interest in cleanroom manufacturing early in their undergraduate education.
Compared to other leading engineering schools, Virginia Tech is admittedly late in establishing a cleanroom capability. But funds it received as part of a state incentive plan to lure semiconductor fabs to the region is helping it catch up and create the undergraduate micro-fab. "Our first facility is not a traditional research cleanroom in terms of the tooling," says Hendricks. "But people interested in developing training programs will find it unique."
Only 16 students and their instructors—no more than 20 people—will enter the cleanroom at one time. Although it was designed as an ISO Class 7 (Fed-Std-209E Class 10,000) facility, the cleanroom will operate at ISO Class 6 (Class 1,000) at the request of local semiconductor fab managers who want potential student interns and employees to be familiar with more stringent protocols, including full gowning procedures. The students will work on a single four-inch wafer in teams of four, where they will build p-n junctions, MOSFETS and other simple devices using a solid-state diffusion process.
Safety of the students, some still in their teens, is paramount, says Hendricks. After attending a lecture on the theory of a specific process step, each student must view a digitized video of the step accessible over the Web. Then, they watch as an instructor demonstrates the step in the lab before they attempt to perform it themselves in the cleanroom. The entire process involves four masks and takes six lab periods to complete. The cleanroom houses a set of ModuLab educational tools from Electro-Mechanical Services (Albuquerque, NM).
The tools include an oxidation furnace, two diffusion furnaces (n-type and p-type), a photolithography station, two wet processing benches, a physical vapor deposition system and two computer-automated microprobe test stations.
The tools were delivered more than a year ago and set up in a non-clean lab, where a group of materials science and engineering students working on their senior projects developed an initial process. The students mastered several process steps, including oxidation, diffusion, photolithography, etching and PVD metallization, and later made working MOSFETS at 100-micron resolution. This same process is now used in the cleanroom.
Charlie French, a materials science and engineering major who helped develop the process, says the new cleanroom will be a big improvement over the lab. "There were problems with the wafers and devices [in the lab] that we weren't able to explain," French says, attributing the problems to particle contamination. "Besides giving us exposure to how an actual fab works, the cleanroom will allow us to develop a cleaner, more exact process with not as much particle contamination in the atmosphere."
Coursework in the undergrad cleanroom will be a pre-requisite to working in Virginia Tech's $7.8 million advanced research fab. The ISO Class 7 to 5 (Fed-Std-209E Class 10,000 to Class 100) 5,100-sq.-ft. facility is expected to open in 2002.
Other major engineering schools offer hands-on undergrad training in non-clean labs. Georgia Tech's Microelectronics Research Center (MiRC; Atlanta) has such a lab where laminar flow hoods protect key equipment. About 60 students, mostly seniors, learn about semiconductor manufacturing in the 650-sq.-ft. room by processing two-inch wafers. The elective class runs one term. Last fall, a class on MEMs also began using the lab.
The lab environment helps train students to use Georgia Tech's research cleanroom. Last year, the university added 1,500 sq. ft. to the predominately ISO Class 4 (Fed-Std-209E Class 10) cleanroom, which now totals 8,500 sq. ft. Some 150 people—graduate students, faculty and outside researchers—use the cleanroom for advanced research, says Gerald Hill, Sr., associate director of operations at MiRC.
In addition, six undergrad students work in the cleanroom helping technicians, installing equipment, ordering consumables and repair parts from vendors, and handling cleanroom laundry chores.
Emphasis on training is increasing as industry strives to find sufficient numbers of technologically skilled workers. As reported in the August 2000 issue of CleanRooms, the number of students enrolled in technical degree programs plummeted over the past decade. Nationally, there's a shortfall of 25,000 technicians over the next three years.