As the global appetite for sending and receiving voice, data and video continues to increase, networks will need to become more powerful and more efficient to keep pace.
In turn, optical networks require optical switch systems that directly route multi-wavelength photonic signals between thousands of different destinations, or ports. Recent estimation of the worldwide market for optical switch systems is forecasted to grow from $234 million in 2000 to $7.4 billion by 2004.
The healthy projections have yielded many new facilities, and a Southern California based company recently completed a fab for the production of micro electro-mechanical systems (MEMS) optical switches, the basis for communication over a telecommunications network.
This way, not that way
Clean Rooms West (Tustin, CA) was contracted for the design/build construction of the cleanroom, as well as, the general contractor for all related processes and as a consulant in choosing the facility.
The actual request for a quote was drafted and bid upon before the building was even leased, and all the while, the customer remained poised to select another building if the cleanroom could not be "built to spec" the way the chip maker wanted. The 37,000-square-foot-facility features a 6,000-square-foot E-shaped ISO Class 6 and ISO Class 7 cleanroom.
Gowning, testing, assembly and measurement areas are housed in the Class 7 space, while lithography, wet processing and etching deposition are conducted in the Class 6 area.
The cleanroom uses two 80-ton chillers from Trane Co. (Lacrosse, WI), incorporates 11,500 cubic feet per minute (CFM) of exhaust and a 33,500-CFM Trane air handler for supply air. The room, the second portion of a multi-phase project, was completed ahead of schedule and took seven months to complete.
Designing the cleanroom to follow the layout of the building was also a key factor. The "E" shape of the room followed constraints from the building and the landlord, because the wall that makes the "E" could not be torn down.
Adding to the challenge, the landlord also insisted that an underground trench, relying on gravity and not sumps, be burrowed under existing concrete slabs for waste removal. Tim Allison, of Clean Rooms West, served as on-site project manager and managed all phases of construction.The project presented many design challenges, forcing Allison to make decisions on the fly. One of which was during the installation of the process piping for wet benches and the gravity waste system, designed by locally based Murray Co.
"A measurement taken during planning by another of the subcontractors was off by about three feet and the waste system would not fit in the area designed for the piping. We were able to recognize the problem quickly and determine a solution within hours of the situation being recognized," Allison says. "Without a project manager in place, a situation like this could have easily delayed the project by weeks before a solution was found." Download the PDF of the piping system
Keeping it clean
The cleanroom has very specific protocols for gowning as well as entering and exiting. Booties are required before entry to the gown room and full gowns are used, including facemasks, gloves and goggles. Cleanrooms are maintained at a temperature of 69 degrees Fahrenheit, plus or minus one degree, with a relative humidity of 45 percent, plus or minus five percent.
The facility was built to exceed the requirements set by the South Coast Air Quality Management District of California. Dual volatile organic compound (VOC) carbon units and scrubbers from Air Chem Systems Inc. (Huntington Beach, CA) were installed to accommodate expansion without installing an ancillary system in the future. The dual units were used in case one unit went bad or was shut down. With two units, the potential for hazardous material escaping into the outside air is dramatically lessened.Engineers, however, had another problem to deal with once the scrubbers, chillers and pumps were fired up: Noise. Because the equipment was outside, the constant shriek was causing neighbors to complain.
Sound attenuating panels were then installed around the scrubbers, chillers and pumps, and later extra panels were installed to ensure the surrounding neighborhood would be undisturbed with the noise level from the facility.
"The entire facility also meets California building requirements for seismic zone 4. This provides added protection in case of earthquakes," Allison adds.
Working with a team
In this case, the project would never have started had everyone not bought into the specs presented or the ability to modify those same plans during construction. The electrical contractor, Quintero's Electric, started with 400 amps coming into the building. By the time the project was complete, there were 2,400 amps coming into the building for the cleanroom and equipment.
The local building inspectors were brought in to see the facility and gave their blessings to begin construction without full permits being issued. CRW went to the city planners to coordinate planning/build, off-site sewers, SCAQMD restrictions, industrial waste concerns and fire safety issues.
Additionally, the waste system needed to be fed directly into the city sewer system and additional systems needed to be installed to meet waste requirements. Having met and worked with the city planners early in the process, the planners knew the project and were able to accommodate these needs in a timely manner.
Size of facility: 37,256 square feet, of which more than 6,000 square feet is ISO Class 6 and 7 cleanroom space.Purpose of facility: Manufacture of optical switch subsystems.Designer(s): Clean Rooms West Inc. designed and built cleanroom and HVAC systems; Quintero's electric installed electrical systems.
Reprinted from CleanRooms Magazine, March 2002
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