BUILT TO SPEC: Cool and Clean Optoelectronics

Lucent&#39s opto-campus gets bigger and better cleanrooms for optical device manufacturing


by James F. Dormer, manager, MRC, Lucent Technologies, Inc.

Question: How did Lucent Technologies, Inc. keep products in a clean environment, yet eliminate people from the same environment?

Answer: They brought the cleanroom to the process facility.

New mini-cleanrooms with pick-and-place robots are used to build laser assemblies. These assemblies sare used in many applications, such as cable television or dense wave-division multiplexing (DWDM).
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When Lucent staff began brainstorming to build what is now the Manufacturing Realization Center (MRC), they made several observations that resulted in a new approach to facility design. For instance, not only were large cleanrooms very expensive, but maintenance costs were prohibitive when compared with expenditures for non-cleanroom work areas. All assembly and test operations requiring a low contamination environment are performed in modules, but the factory floor just outside the clean environment is considered ordinary workspace.

Another observation made were the existence of conditions limiting what the staff could accomplish within the new cleanrooms. These limitations include the inability to install carpeting in a cleanroom and the necessity of specific types of tile floors, mats, hoods, gloves, and shoe covers. By scaling a traditional cleanroom down to the minimum volume necessary to hold production equipment, a dividing line was drawn.

With a $10 million investment, Lucent opened the MRC in January 1997. By doing so, the company created a facility that re-engineers the manufacture of laser packages. By 1998, demand required the expansion of the MRC, and Lucent increased the floor space by 50 percent, which increased the area from approximately 20,000 ft2 to 30,000 ft2.

The forthcoming manufacturing facility at Lucent’s Optoelectronic headquarters in Breinigsville, PA, will produce an abundant supply of economical laser assemblies.
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By the end of the year, Lucent will complete construction on an additional 125,000-ft2 expansion for the assembly and test of laser components. The expansion also includes 18,000 ft2 for offices and laboratories. The new facility will be located near the optoelectronics headquarters, and will house the manufacturing, assembly, and testing facilities for a majority of Lucent&#39s optoelectronics devices. The remaining devices will be produced in Matamoros, Mexico and in two U.S. sites, Reading, PA and Murray Hill, NJ.

The nearby Reading building has received an additional $6 million to produce next-generation photodetector products, bringing the total investment in the latest round of new construction, expansion, and facility upgrade to $30 million. Twenty-five percent of the Reading facility is dedicated to optoelectronics.

Within Lucent&#39s operation, less than 10 percent of the total square footage is actually cleanroom space. In comparison, a traditional cleanroom in the past would have required 70 percent of the available square footage. The staff also modified many pieces of traditional equipment to incorporate their cleanroom concepts. Robotics are heavily relied upon within clean enclosures, HEPA filters are built into the top of clean structures, and structures are cut open on the underside to enable air to flow out.

Lucent based its modification of traditional cleanroom design on internally conducted experiments, especially those relating to equipment design and development. Ultimately, the conceptual changes initiated meant that employees could shed their masks and traditional cleanroom garb. The carpeting of floors in the areas surrounding the equipment provided a nicer work environment, yet left the inside of the equipment qualified as a clean environment. Employees and operations actually reside in areas not required to be within a “cleanroom.”

Employees wear a white smock used solely for ESD protection, but do not wear booties, masks, or hoods. Gloves are worn only when loading products into machines and working directly inside the machines. Within the enclosures, space is treated as traditional cleanrooms would be. These areas are paper free, aluminum fixtures are anodized to avoid particle shedding, and automatic mechanisms are designed to cleanroom standards. For example, encoders and lead screws are protected just as if in a cleanroom. Within the facility, clean areas are Class 100 and Class 1000.

Automating processes to avoid manual assembly or manual testing presents a difficult challenge. Moving production from the hands of a person sitting in a cleanroom environment to an isolated environment dramatically increases flexibility results. Lucent invented the equipment and methods, which provided greater flexibility. A Lucent-designed 2-inch2 ESD-safe waffle pack to house and handle optical devices addresses the protection of devices during material handling. Automated assembly and test equipment takes place within the housing, allowing for hands-off processing without loss, contamination, or damage.

Lucent discovers other benefits during this process. One: using small-volume clean areas eliminates the need for multiple air handlers and return air chases. Two: A major construction challenge is to make sure a sufficient volume of air is available within all of the facilities. Typically, seven to eight air-handlers provide airflow. However, in the new facility needs only one air-handler to provide all the clean air necessary to the equipment within the existing 30,000-ft2 facility. Clean air is funneled only to the interior of the minienvironments, where the process actually takes place. Although the concept is similar to minienvironments used in other industries, it is unique within the optoelectronics industry.

Strategic Facility Stats and Layout

Optical products are extremely sensitive to electrostatic damage, so building a Class 0 ESD area is critical to the cleanroom&#39s success. Therefore, all enclosures are non-static generating and constructed from such materials as ESD-safe plastic.

The humidity of the air within the building&#39s clean environment is extremely important to prevent a build-up of static charge. The volume of air has to be sufficiently humid and ESD controlled. Ideally, temperature and humidity is maintained at 45 percent relative humidity at 72°F, +2°F. The air conditioning has a built-in safety system, and the facility is unaffected by hot, humid, or dry weather outside of the building. If an overall power grid failure occurs and the facility shuts down because test equipment needs to run continually, the amount of time necessary to return the facility back to a cleanroom level is substantially reduced, given the small volume of air used. Airflow is positive within the facility and outside air is mixed in, although it is recirculated.

The staff reviews the entire layout of the process during the facility&#39s design phase, seeking to further eliminate boundary conditions inherent in a traditional cleanroom. By lining up the entire process so that the product flows exactly as it needs to in order to be assembled and tested, many of these boundaries are automatically removed. To improve communications between the manufacturing, engineering, and development staff, the offices for manufacturing, development, and management are placed directly on the shop floor in the center. The outside walls are lined with equipment. The move dramatically improves communications within the facility and gowns no longer are required to enter clean space.

Lucent created a new job classification specifically for technicians working at the facility. The technician is responsible not only for production, but also for preventive maintenance and equipment repair. Employment opportunities in this new category do not place the technician inside the clean environment, minimizing the amount of cleanroom culture training necessary. Training includes the ramifications of changing anything within a clean area, but general work is performed outside of the cleanroom itself.

Contamination and ESD Control

Upon opening each phase of the campus, all systems and equipment are closely monitored. Today, the ESD program is all encompassing. It includes such components as static dissipative carpeting and an ESD smock that reduces charge when mobile. Also, ESD shoes, heel, or toe straps are chosen based on personal preference. For some operations, wrist straps are used to connect personnel to a ground.

Each facility is designed from materials that dissipate, or from metal. Periodic checks are performed on the facility and each employee also checks their individual ESD status, with all points connected to the system to provide real-time analysis. Clean areas are completely paperless with no paper-based data generated during testing operations. Tracking of parts and history is also performed electronically through a central database.

Lucent designed and built more than 80 percent of the facility&#39s equipment. The company developed its own custom design and development group that continues to build necessary process and manufacturing equipment to spec.

Eliminating substantial cleanroom requirements also allows facility designers to enjoy flexibility in the choice of construction materials. The operation uses only non-toxic gases, which are typically high-purity helium and nitrogen and compressed air.

Comparative Cost

Operating a cleanroom with Lucent&#39s method is definitely less expensive. Providing ground-connected wandering capability and ESD smocks is substantially less costly than its traditional full-garment counterpart. One air-handling unit provides clean air rather than requiring seven units per cleanroom tunnel. Traditionally, approximately 10,000 to 20,000 ft2 would have been required to house the facility&#39s equipment resident, resulting in a very high cost.

The S1730 EDFA, measuring roughly 3 in. x 4 in. x 3/4 in., is the industry’s smallest full-amplifier module. Lucent will double its EDFA manufacturing capacity throughput next year.
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There is also a corresponding positive impact on product costs. One specific optical device, redesigned on campus, saw a cost reduction of more than 50 percent. Fortunately, Lucent has discovered a way to leave behind difficult manual assemblies by replacing them with automation that isolates the process from the person. These changes are paying off in revenues, employee satisfaction, and product reliability.

Not only is automation developed for specific product production, but these methods can be reused when introducing new product families and new generations of products. The result is a record time-to-market. The creation from the ground up of a no-boundary-condition facility solution to manufacturing and assembly involved many individuals from manufacturing, development, and research. The program gives Lucent an opportunity to rethink how they do business, resulting in the invention of new platforms and processes.


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