Cleanrooms go from dust busters to molecular terminators
Today, contamination control technology is moving beyond its initial role: to eliminate dust and particulate, and to in ves tigate why contamination levels breached raised barriers. As the technology matures, its practitioners are beginning to revise the way they set up guidelines, share information among their respective industries, and create training methods and programs. These are the important issues as the year 2000 nears.
A contamination enemy is identified: molecular contamination, condensable vapors that form film on sensitive surfaces. This represents the primary contamination control battleground of the early years of the millennium.
According to Alvin Lieberman, “the electronics industry requires uniform coating on semiconductors, requiring the elimination of gaseous contaminants; and pharmaceutical companies attempt to eliminate the organic film coating inorganic powders, which may prevent capsule formation.” Lieberman is the chair of IEST Working Group 9, “Compendium of Standards, Practices, Methods and Similar Documents Relating to Contamination Control.”
The physical environment is also changing. The technology migrated from clean benches to large, but astronomically expensive, ballroom cleanrooms. Today, the shift is back to micro — from ballroom-type cleanrooms to relatively clean ballrooms, housing clean zones or enclosed and protected minienvironments. And within these smaller environments, personnel operating tools are increasingly being replaced by robotic systems to ensure fewer mistakes and less contamination than their human counterparts.
Another recent development, says Lieberman, “is the use of micromachines — capitalizing on technology used to deposit circuits on chips, gears and valve systems such as gas chromatographic systems, flow control systems, and analytical devices as small as one micron are now being placed on chips.” As geometries continue to decrease, and systems-on-a-chip become more prevalent, this type of manufacturing is expected to expand.
According to Charles Berndt, chair of the IEST Working Group on Automotive Paint Spray Applications, “now, and in the early years of 2000, other industries such as food and automotive will expand their awareness of the benefits of contamination control. Processing and packaging of food in a controlled environment, for example, eliminates microbial contamination, lengthens shelf life, and reduces the need for preservatives. This increase in shelf life goes straight to the company`s bottom line as profit.”
An expansion of contamination control methods includes increased interest on the part of the automotive industry and automotive aftermarket. The industry looks to cleanroom technology on two levels — first to avoid paint blemishes caused by particulate contamination during the painting process. Automotive paint includes automotive manufacture, assembly plants, parts plants, and body shop environments. “Through IEST`s efforts with the Specialty Equipment Manufacturer`s Association (SEMA; Diamond Bar, CA), the aftermarket is just beginning to be aware of the benefits of contamination control,” says Berndt.
The second automotive application involves a migration of technology from one area of contamination control to be used in another. “Air pollution is beginning to be such a critical problem in automotive cabins, the industry is considering using cabin ventilation based on cleanroom air systems — HEPA filters,” says Lieberman of IEST Working group 9. “The question then becomes, `will car owners maintain filters as would be necessary to be effective?` It`s easier to throw away a $5 relatively low-efficiency filter than a $20 HEPA filter.”
Finally, the expansion of the number of industries adopting contamination control policies will require an expansion of support products from cleanroom suppliers and vendors, tailored to the needs of emerging industries.
Can we talk?
Industries using cleanroom technology naturally approach problems from their unique vantage points and solve problems based on their own needs and research. Referring to contamination control in water systems within two industries — semiconductors and pharmaceuticals — Lieberman demonstrates the issue. “The pharmaceutical industry understands how to remove viable materials and keep them out of the water system, but is challenged by keeping the particle content of water down to a level two orders of magnitude dirtier than that handled by the semiconductor industry. Likewise, the semiconductor industry has mastered filtering water — removing inert particles and keeping them out at the point-of-use. Yet, they have a considerable challenge with their water systems being contaminated with viable materials — mold, yeast, and bacteria.”
The dilemma: industries seldom share information, a problem concerning not only the two largest industries, but aerospace, health care, and hydraulic fluid power systems camps.
IEST Working Group 902, chaired by Joyce Steakley, is spearheading an historic event on two counts. Military standards and military documents are imposed on military contracts for cleanliness and surfaces for cleanrooms, and are controlled and regulated by the government — until now. Private industry has advanced the state-of-the-art to the extent that government no longer leads in research and development. As a result, the government is finally encouraging the use of commercially available practices, standards, approaches, and technologies, eliminating the necessity for two sets of standards and practices.
The second important aspect is that, “although IEST normally publishes recommended practices, it will be replacing Mil-Std 1246 with an IEST standard during the first half of 1999,” says Steakley. “The difference between RPs and standards is that an RP says `here are some good ideas.` A standard says `here is a definition with hard criteria to define things like levels of cleanliness and cleanroom classification.` It`s a defining document containing methods to measure defined levels or limits that are repeatable, reliable, and demonstrated acceptable.”
Once the IEST standard replaces Mil-Std 1246, it will be taken to ANSI to become an ANSI/IEST standard. Eventually, there is hope it will become an ISO standard. Today, there`s also an increased willingness on the part of U.S. industries and government to accept ISO standards.
Hot topic: education
As with any rapidly evolving industry, a major challenge becomes getting information out into the hands of users in a concise and timely manner. Fueled by such changes as the imminent introduction of ISO documents, coupled with revisions of long-standing recommended practices, and the emergence of molecular contamination issues, courses are beginning to reach out to attendees nationwide and attendees are responding.
According to Bob Spector, IEST Working Group 16 chair, “for the IEST Fall Conference in Chicago, even with a 50-percent increase in hotel costs, a tripling of conference fees, and a marked slowdown in the semiconductor industry causing many austerity programs to kick in, the conference was better attended than in previous years.”
“An IEST certification program is beginning to be discussed seriously. IEST`s educational advisory group is reviewing options, including what kinds of classes need to be developed, potential partnerships with universities, and CD ROM for interactive training,” says Steakley. “It`s more work up front, but it`s sustainable, and will reach a more diverse and larger audience.”
“Every industry is financially driven these days. We need to constantly review ways of reaching our audience. You can`t put the information on the Web and have it make money — you still have to sell what you have to offer,” says Steakley.
Berndt agrees. “The biggest issue in this field today is one of awareness and education. That`s the transition that needs to occur to meet the challenges coming in the year 2000 and beyond,” he says. “We have to present enough information to give people an appreciation for potential applications.”