Yield is key in designing new facility for Input/Output

Yield is key in designing new facility for Input/Output

Cleanroom space keeps company on cutting edge

By Judy Keller

When a new high-technology facility is completed ahead of schedule, is under budget and everything works, what`s left to brag about? Plenty, claim company officials from Input/Output, Inc., the owners of a new 110,00-square-foot seismic tool manufacturing center in Stafford, TX. Lepco, Inc., a Houston-based firm providing turnkey construction, engineering, testing and service support for advanced technology facilities, finished the $12 million building in a scant 11 months.

The year-old plant is the only one in the country producing six-inch wafers using high yield, high volume Micro Machine Microsystems.

This pleases folks at both companies, but the bottom line is the cleanrooms and clean space in the facility are the enabling technology that allows Input/Output to keep its cutting edge. Without the new 19,000 square feet of Class 100 to Class 100,000 clean space, Input/Output would not be on the verge of unveiling its next generation of seismic data acquisition systems: 3-D and 4-D (three and four-component data) survey tools that could be used to collect data from underground reservoirs of gas or oil over time and display it on a high-resolution screen. Designed for gas and oil exploration, the technology could have military uses, too, because it is designed for use in harsh environments. Without the high yield possible in the new facility, however, it simply would not be commercially feasible to develop the micro-electromechanical systems (MEMS)-based technology.

MEMS are exactly what their name implies: microscopic machines about the same size as a semiconductor, using similar manufacturing techniques and requiring a clean manufacturing environment while using toxic chemical etches. Input/Output officials say they have found a way to work on both sides of the wafer at once, and this helps increase yield. Input/Output has been making seismic data acquisition tools for nearly three decades. It makes cabled land seismic data acquisition systems, radio telemetry systems, marine systems and sensors and energy sources.

Yield increases

“Without our new facility, none of this would be possible. MEMS are critical to us right now, as we literally use hundreds of thousands of sensors in one system,” says Axel M. Sigmar, vice president of corporate development at Input/Output. “It`s very significant that they [Lepco] could help us get ahead of the yield curve for MEMS. We are able to run with fewer people and get a yield above and better than anyone in the MEMS community could expect. We are very satisfied.” While most MEMS manufacturers are satisfied with a 50 percent yield, Input/Output executives have reported yields of higher than 90 percent.

The Lepco designers and builders brought more than a speedy finish to the project, however. Gary H. Devloo, Lepco president, points out that Lepco has pioneered many industry developments such as proprietary membrane diffusion technology for distribution of clean air and integration of natural gas fuel-based chillers for energy efficiency. “We brought 28 years of experience in building microelectronics factories to the table,” Devloo says. He adds that Lepco designers and builders considered several sites for the plant and finally chose one adjacent to Input/Output`s research and development center at its headquarters in Stafford, TX. The site won hands down over one in San Jose, CA, and another in Austin, TX, mostly due to lower land, material and labor costs.

For its new structure, Input/Output needed some 11,000 square feet of Class 100 to Class 100,000 clean space with temperatures controlled at 68 degrees Fahrenheit (&#1772 degrees Fahrenheit) and humidity controlled at 45 percent RH (&#177 5 percent RH), plus an additional 75,000 square feet of mechanically and process-intensive manufacturing space with a 4,500-square-foot equipment mezzanine. The plant includes a complete six-inch cleanroom wafer fab for photolithography, wet etch, chemical vapor deposition, bonding, testing, assembling and packaging. Its process systems include an 18 megaohm, 80 GPM deionized water system, clean/dry air system, high purity nitrogen, central process vacuum system, on-site waste neutralization system, acid and solvent exhaust systems totaling 18,000 CFM, acid and solvent drain and collection systems, process chilled water loops, and all gas cabinet and specialty hazard chemical storage and exhaust systems.

The facility`s mechanical mezzanine contains acid and solvent exhaust scrubbers, process chilled water systems, and primary and secondary HVAC systems that move more than 412,00 CFM of air. There are primary blowers and air handlers in the space envelope above the cleanrooms to recirculate the air required for the cleanliness class of each space. Extensive ductwork forms a gleaming, metallic maze in the space envelope, with primary distribution ductwork feeding to HEPA air filters. Fiberglass-reinforced ductwork takes care of plastic, acid, and solvent exhaust. The blowers recirculate the air required for each class of cleanroom.

A 900-ton central chilled water facility provides all the HVAC and chilled water for the offices and manufacturing areas. The system is redundant, using electrical centrifugal chillers from McQuay International (Minneapolis, MN) and gas-engine chillers from Tecogen, a division of Thermo Power Corp. (Waltham, MA). The two chillers work in tandem with two, separate 450-ton cooling towers from Baltimore Air Coil (Jessup, MD).

For higher efficiency, about 40 percent of the load is captured in a gas fuel-based unit, including a system that allows a large portion of the rejected heat to be used in the plant`s hot water and steam.

Power sources

All this uses energy — lots of energy. “In fact, that`s the largest component of the plant`s operating cost,” Devloo says. The facility is serviced by two Houston Lighting and Power grids and 6.6 megawatts of pad-mounted transformers — enough to light up a small town, Devloo notes. Lepco designers engineered the main building feeds as well as all process facility infrastructure. The two grids are connected to Lepco-designed static switches that can switch 2 megawatts of power in less than one quarter of a cycle, or 1/240th of a second — faster than most computers. He estimates that the Lepco design saves Input/Output about $250,000 annually in electrical operating costs.

The two power sources are constantly monitored and analyzed automatically to select which power source is the “most pure,” that is, which one has the fewest amperage fluctuations. In case the power fails, Lepco included a backup generator for the safety systems and for a non-interruptible power supply backup for critical equipment.

“Safety is a major factor in the design, too. We never forget that people work in the building,” Devloo says. “We have to not only provide the environment that`s best for the product manufacturing going on, but take care of keeping the toxins away from the people in there.”

A system of redundant direct digital control (DDC) and monitoring sensors allows Input/Output to monitor and control the entire plant from a computer screen, keyboard and mouse, locally or remotely.

“That means the plant manager could be in a grocery store wearing a pager that sounds an alarm. With a few keystrokes on a laptop computer, he can dial in and see a run-through of the plant faster than physically walking through the whole structure, and then, with a few more keystrokes, can take care of the situation,” Devloo says. “The whole plant is totally controlled with a Lepco Auto-Matrix DDC.” Lepco was the sole source engineer and general contractor, responsible for each phase of the project. The company handled all site evaluation, development engineering, building and site constructions, landscaping, office build out, cleanroom installation and process utility systems, permitting, testing and plant operations. Lepco personnel designed and engineered owner process tools, fit-up and commissioning. The company also handles all plant operations at the facility, and has maintained and operated the structure for its first year. Company officials report that “everything works” and only minor tweaks and adjustments were needed during the first 12 months.

Flexibility is key

Input/Output is putting its money on MEMS these days, and is seeking partnerships with other companies interested in applications of MEMS technology. And when business starts booming beyond the seismic data tool stage, the company`s new manufacturing structure can be readily adapted.

“The modules at Input/Output are laid out already so that the clean space could double in size. We`ve preplaced trenches in the concrete, allowed space for utilities and wiring and ductwork. It`s a flexible, forward-looking design, and could be modified quickly,” Devloo says.

As if to prove that the design is really flexible, Input/Output officials realized a humidity control room was needed for some other processes, not connected to the clean spaces.

“Lepco built us a 2,100-square-foot, temperature-controlled room in a weekend. We called them late on Friday, and when people came in for work that Monday, they were amazed to see a first class, permanent structure in place and recording responses,” Sigmar says.

Meanwhile, Input/Output races toward making a reliable reservoir monitoring instrumentation system, which may soon be breaking news for the fields of oil and gas exploration — and cause for more bragging rights, all possible because of a cost-effective, high-yield cleanroom environment. CR

Judy Keller is a freelance writer based in Milford, NH.

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View from a Class 100 front-end cleanroom tunnel looking through the clean viewing corridor into the Class 10,000 back-end assembly area with Lepco`s membrane diffusion ceiling system throughout for complete laminar air flow.

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View looking parallel to the 130-foot clean viewing corridor showing the ends of the Class 100 tunnels and chase systems.

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View from inside a Class 100 air return chase looking into a Class 100 tunnel containing six-inch wafer process tools in which Lepco designed, hooked-up and ran all process piping.


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