Prototype`s Success Leads to Company`s First Cleanroom
By Sheila Galatowitsch
Woburn, MA–The transition from bench-top to full-scale manufacturing sometimes happens at lightning speed. For Applied Science and Technology Inc. (ASTeX; Woburn, MA), it happened in six months. This is the story of how a rapidly growing start-up built its first cleanroom, from concept to finish, and in less than a week after moving into the building, started shipping products manufactured in the room.
In early 1995, ASTeX had a problem. Semiconductor capital equipment manufacturers were snapping up prototype versions of its latest product and the company knew its bench-top manufacturing setting wouldn`t be able to keep up with demand much longer. Full-volume production capacity was needed immediately.
And, while its customers had not yet insisted on cleanroom manufacturing, ASTeX knew they soon would be as the semiconductor industry increasingly requires its suppliers to adopt cleanroom standards. The obvious solution was for ASTeX to build a full-scale cleanroom manufacturing facility, but it had to be done quickly and cheaply.
MIT spin-off
ASTeX is a classic case of a high-tech university spin-off. Company founders were engaged in fusion energy research on the campus of the Massachusetts Institute of Technology (MIT; Cambridge, MA) in the early 1980s. After the Department of Energy ceased funding, ASTeX was founded in 1987. “We hit the ground running,” says CFO John Tarrh, one of the founders. “We had so much fusion technology and physics under our belt, we were able to develop products quickly and bring them to market.” ASTeX was profitable in its first year and in eight of the last nine years.
The company sells turnkey production systems to producers of chemical vapor deposition (CVD) diamond, and microwave power generators, plasma sources, and ozone generators to semiconductor capital equipment manufacturers. It is the success of the ozone generator product that led to the need for a cleanroom.
ASTeX is the largest company in the U.S., and one of a few worldwide, manufacturing ozone generators for the semiconductor industry. Customers use the generators to grow insulating layers of silicon dioxide dielectric in semiconductor devices. In most cases, the generators are delivered directly to a customer`s cleanroom.
By March 1995, the company had decided to construct its cleanroom using the “design-build” approach: Designers work intimately with the builders, decisions are implemented at once without rebidding, and there is a fixed price for the project that can`t be exceeded. ASTeX allotted approximately $1 million for the project–$500,000 for construction and $500,000 for equipment purchases.
John Lloyd, ASTeX`s vice president for manufacturing operations, had just been hired when the prototype was launched. Designing and constructing a cleanroom turned out to be one of his first tasks. Mechanical engineer Gordon Hill, who started with the company eight years ago as a summer intern, was appointed technical project manager. Robert Kaplan served as the business project manager, negotiating contracts and managing schedules.
Planning and designing
Hill based the cleanroom layout on ozone generator production goals. Initial capacity had to number 700 generators a year. With the purchase of new semiautomated equipment, production would nearly double. Hill ultimately designed the cleanroom to support production of three times its current capacity.
At this point, ASTeX was leasing 30,000 ft2 of a 60,000 ft2 building. Half of the space contained office and development labs, and half was a manufacturing area. Based on Hill`s initial specs, the company decided to lease another 8,000 ft2 that would be totally dedicated to the ozone generator product. This “miniplant” concept included 4,000 ft2 for office space and storage, and 4,000 ft2 for the manufacturing area, which would ultimately feature a 2,400 ft2 cleanroom.
Working with AutoCad software, Hill experimented with process flow, layout and equipment placement. Edmund Britt, an industrial designer hired as a consultant to the project, suggested building a wooden block model of the design. The model was set up in the company cafeteria, allowing employees from all departments to try out different layouts and floor plans. “We actually went through several iterations of laying out the area to accommodate efficient use of space and process flow,” Hill says. The final layout was ready on June 1, and the company started looking for a general contractor.
ASTeX eventually hired Patrick Maloney, owner of Architectural Environments Inc. (Chelmsford, MA), who had experience building cleanrooms for area biotech firms. Maloney says his first task was to decide what options were available within ASTeX`s budget. This is a “backwards” approach, according to Maloney. “Typically you do a design, the budget and value engineering–in that order,” he says. “We did value engineering first to define what kind of a room we could give them. The design was almost the last thing to come.”
Maloney quickly hired mechanical engineer Norman Springer of Poirier Springer Inc. (Billerica, MA), a 40-year veteran of cleanroom construction projects. Springer specified equipment needs to meet the cleanroom criteria. ASTeX initially planned to build the entire space to Class 100 specs, but that turned out to be too expensive, Springer says. He suggested enclosing only critical tasks in Class 100 areas and building the overall room to Class 100,000.
Once the mechanical design was laid out, the remaining subcontractors were hired. Electricians and Co., Inc. (Malden, MA) and Thomson Engineering (Boston, MA) did the electrical engineering. Barstow Engineering (Boston, MA) assisted Poirier Springer with the mechanical engineering. Amescor! Inc. (Concord, NH) and O`Keefe Plumbing and Heating (Malden, MA) were responsible for the nitrogen piping and plumbing systems, and Marc Hershman of MSH Architecture Associates (Arlington, MA) was called in as the design architect.
Construction
In 12 weeks, the team directed by Maloney defined, designed and built the new facility. Construction itself was finished in just under eight weeks. “We spent an extra week or two working out bugs,” Maloney says. “Those couple of extra weeks helped shorten construction time.”
The cleanroom has a drywall construction with epoxy paint; sealed walls, caulked top and bottom; cleanroom ceiling tiles; low wall air returns; and a large central bag filter. Although it was built to a 100,000 classification, Hill says recent particulate counts show the room to be operating under Class 10,000. Class 100 is maintained in two softwall rooms, each measuring 6 ¥ 6 ft, where the most critical steps of the manufacturing process are completed. The design also features a room that houses the particulate-generating activities of the manufacturing process.
A series of transfer rooms–a gowning room, a wash room, a parts-in and a parts-out room–occupy one end of the cleanroom. Each measures approximately 8 䁾 ft. On one side of an access hallway, there are two other 26- ¥ 12-ft Class 100,000 rooms used for R&D and manufacturing subassemblies. Another room measuring 100 ft2 houses a water chiller controller and gas bottles.
Positive air pressure in the cleanroom is reduced to intermediate pressure in the transfer rooms with the lowest pressure room being the room which houses the particulate-generating part of the manufacturing process. Fifteen people currently work in the manufacturing area, producing several ozone generators a day. After the assembled generator comes off the production line, it is bagged in the parts-out room and leaves the area in a shipping crate.
Special features
Eight-foot-high double doors were installed in the parts-in and parts-out rooms to accommodate the bulky rack-mounted configurations. The team also designed two-foot-cube pass-thru boxes to transfer parts from room to room without impacting cleanliness. The pass-thrus have plexiglass doors, are fully gasketed and maintain room pressures. “These are the type of things that are designed as you go,” Maloney says.
The cleanroom features a high-purity gas distribution system, plumbing that meets semiconductor industry standards, an electrostatic discharge station, and a 3,000-gallon liquid oxygen tank located in the rear of the building on an external pad. It was halfway through the project when ASTeX decided it needed the bulk storage oxygen tank. This “curve ball” required a redesign of the gas and process piping, Maloney says. It also called for backup systems that could switch from the tank to bottles to keep the plant in operation in an emergency.
The need for future expansion led ASTeX to install a 40-kW chilled water system, even though it is consuming only 15 to 20 kW at present capacity. To avoid running process water outside the cleanroom where it could freeze in winter months, and having the condenser inside the room itself, the condenser and compressor were placed on a steel platform on the roof, and the pump and evaporator were placed in a service room. This positioning exhausts heat directly to the outdoors.
Even with the addition of an air handling unit on the roof platform, half of it is still available for more equipment. The design allows the entire operation to double with no disruption to manufacturing activities. Extra stations are also available within the cleanroom for water cooling, power and gas service.
ASTeX`s insistence upon a large observation window made it challenging to fit in equipment, piping and the low wall air returns, according to Maloney. “It got very busy in the room,” he says. “We ended up making rack systems so that they could move pieces of equipment and just plug into services.”
By September 5, the facility was completed and ready for move-in. Despite the fast-track schedule, all parties agree the project went surprisingly smoothly. Now, seven months later, only a couple of hiccups remain. The wash room could have been a little bigger, Hill says, and the lack of a telephone near the observation window has led to a lot of shouting when people try to talk through the window. A phone by the window is expected to solve this problem. n
 |
The ASTeX ozone group includes plasma scientists, electrical, mechanical and manufacturing engineers, technicians, assemblers and administration personnel, some of whom are shown here with the first generator produced in the new cleanroom.
 |
Manufacturing personnel work on cell subassemblies in ASTeX`s cleanroom.