“It’s a great place to work if you’ve got allergies,” said Dr. Henry Lee, who manages the clean rooms at the emerging communications technology institute, on the seventh floor of the Bahen Centre for Information Technology.
He was referring to the fact that the two rooms contain fewer than 10,000 and 1,000 dust particles respectively, per cubic metre of air. By contrast, there’s one to ten billion dust particles in the same volume of air in a typical lecture hall or university building-depending on its griminess.
One of the things made here are MEMS (micro electro mechanical systems): tiny pumps, gears, and motors often no more than ten microns in size-one-tenth the thickness of human hair. Applications are starting to appear in cars, as tiny sensors that trigger airbag deployment, and in electronics, as the tiny, quickly rotating mirrors that mix varying amounts of red, blue, and green to produce crisper colour images in the new-and pricey-television sets based on DLP (digital light processing) technology.
MEMS and other devices are made through a sort of high-tech photography, which uses beams of ultraviolet light to etch patterns onto thin silicon wafers. The wafer itself is coated with a compound called photosense, which hardens when exposed to ultraviolet light. This produces a negative of sorts.
“It’s just like when you do photography,” said Lee. Except that the slightest piece of dust might ruin the picture.
To keep dust out, the rooms are airtight, and kept at 20°C and constant humidity. “Before anything goes in, we’ve gotta get off all the dirt and grease,” explained Lee. Equipment is taken apart, and painstakingly wiped down with alcohol, then vacuumed and blown with nitrogen gas.
The clean rooms are one of several so-called open facilities at U of T. Students from different disciplines simply book time, get trained on equipment, pony up some user fees, and then set about cooking up various small silicon widgets.
Normally, the lab is teeming with up to a dozen white-coated students, according to Lee. But no one besides him, and Yimin Zhou, one of the lab technicians, was in when The Varsity came knocking: one of the students had pulled a no-show; another had called to cancel. Ahhh, to be a graduate student.
