Cleanrooms 2013
06/01/2003
Experts in this CleanRooms virtual roundtable discussion predict the future of advanced manufacturing and build a futuristic facility from the ground up
By Sheila Galatowitsch
Molecular contamination will prove a greater threat, cleanrooms will ship in pre-assembled pieces, and equipment will clean itself. Step into the cleanroom of the future, however, and it will look much like today's facility. Although some of the anticipated changes will radically transform cleanroom design, construction and operation, they will be transparent to most users.
CleanRooms recently asked experts from a range of specialties to envision the cleanroom of the future; and while they didn't agree on every detail surrounding components, equipment and procedures, they all see new user groups adopting clean manufacturing principals.
In 10 years, "a cleanroom will have many different faces depending on who is using it and what the application is," says Michael O'Halloran, director of technology at IDC (Portland, Ore.).
The user base is going to grow beyond anyone's imagination, particularly outside the Western world, says R. Vijayakumar, vice president of technology and marketing for Air Techniques International (Baltimore, Md.). Experts say a global desire for clean air and high-purity products will push clean manufacturing principles deeper into such applications as general retail pharmaceuticals, printing, packaging, automotives, aerospace, cosmetics and food processing (including the retail of perishable foods), and perhaps even into private homes.
"It's not inconceivable that in 10 years a chronically ill or allergic person could adopt cleanroom practices in the home, because all the technologies—filtration, gaseous pollutant removal and materials handling—are currently available," says Vijayakumar. "Indoor air room cleaners are the first example of this. By 2013, cleanroom practices will be ubiquitous."
While new manufacturing users target particles in ISO Class 5-8 rooms, semiconductor and other electronics facilities will shift their focus to contamination control on a molecular level.
In addition, by 2013, a historical concern over airborne contamination will give way to an increasing emphasis on surface contamination and process contamination, says Conor Murray, chairman of the Irish Cleanroom Society and technical director for Ardmac (Dundalk, Ireland). "The challenge will be about removing surface contaminants and in-process contaminants as failure mechanisms."
To do that, engineers will incorporate intelligent monitoring agents as a component part of the product and as part of the in-line process, says Murray. Look for three key ways to combat surface contaminants in the not-too-distant future: self-cleaning cleanrooms with fewer people directly interfacing the process; intelligent devices in self-regulating processes; and intelligent products that have additives or integral components that either do not allow contaminants to cause failures or will flag a contaminant alert.
"Alternative pulsed air movement, nitrogen purging and vacuum operations within minienvironments will increasingly marginalize unidirectional flow to 'lower' grade cleanrooms," adds Murray.
With that introduction, here's a plan for the cleanroom of the future, built from the ground up.
Simplified construction
To Brian Mazur, head of product sales for Aketon Technologies (Corvallis, Ore.), construction will be greatly simplified in 10 years. Cleanroom floors, ceilings and walls will be manufactured in pre-assembled pieces, shipped in one package to the facility site, then snapped together by local contractors using only a few tools.
This Lego-set concept will allow construction of complex cleanrooms in low-tech environments where contractors often have limited experience in cleanroom construction. It will also reduce the cost and construction time of building a cleanroom facility.
The materials that go into the floors, ceilings and walls, says Mazur, will need to be significantly changed to provide more strength with better use of material, but still able to support the increasing weights of front-opening unified pops (FOUPs) and minienvironments.
For example, instead of a tertiary steel system, engineers will design ceiling systems with the structural integrity to be suspended directly to the base building steel, which typically involves longer spans. This approach would make ceiling systems strong enough to handle the weight of the FOUP, piping and a person walking on the ceiling, says Mazur.
Floors will undergo a similar transformation. "I see a change in the floor system from two-by-twos to four-by-fours to accommodate vibration and increasing weights of minienvironments and tools," adds Mazur. "We would like to eliminate all that understructure and have the floor be the final resting place of the tool."
Wall systems will get thinner, stronger and more flexible. "In some electronics and pharmaceutical laboratory cleanrooms, users want the flexibility to accommodate different size tools or to make bigger rooms. When the wall panels can be pulled in and out easily from each side, space can be used more effectively. In a week's time, users could set up for an entirely different process," says Mazur.
LED lights in hybrid settings
Also in the cleanroom of the future, energy costs and maintenance issues will drive out florescent lights and replace them with light-emitting diode (LED) technology.
"Florescent lamps have to be changed every two to three years, often over tools," adds IDC's Mazur. "This risks the possibility of dropping a florescent tube in the room, which can be devastating to the process. LED lights, by contrast, will be more energy efficient, perform for up to 10 years without any maintenance, and can be designed to dim, pulsate or change colors to indicate emergency situations and serve as evacuation guides. The widespread use of LED lights in cleanrooms is one prediction that's a sure bet," Mazur says.
It's also likely that cleanrooms of the future will become more hybrid, says Thomas Hansz, president of Facility Planning & Resources (FPR; Pittsburgh, Pa.). "It used to be if you saw one pharmaceutical formulation fill suite or semiconductor fab, you saw them all. By 2013, cleanrooms will be less generic and more specific to the usersays Vijayakumar.not necessarily specific to the process."
That means unusual combinations of bay and chase, ballroom and suite layouts in a single cleanroom plan, with equipment and utilities designed for easy modifications. "It's all about flexibility and control," says Hansz.
New cleanrooms, same classifications
Even with these construction and layout changes, cleanrooms in 10 years will look much the same as cleanrooms of today. In addition, classification levels will remain constant-not only for particle control, but also for maintenance and airflow.
Although process tools are increasingly isolated from ambient cleanroom air, they still require maintenance and thus periodic exposure to background cleanliness. But perhaps the prime reason why classification levels will stay the same is due to heat.
"A certain amount of air has to move through the cleanroom to provide cooling and remove sensible heat," says Bill Fosnight, vice president of factory hardware engineering at Brooks-PRI Automation (Chelmsford, Mass.).
Created by electrical power, sensible heat can build up to 30 watts per sq. ft. "Airflow entering the cleanroom needs to be 10 to 15 degrees cooler than room air to take away sensible heat, and in the case of wafer fabs, that requires airflow rates corresponding to ISO Class 5 and 6 to remove the heat load," says Fosnight.
Achieving airflow with unidirectional laminar flow, however, may be a thing of the past in 2013, as users replace large distributed fan systems and fan towers with smaller, more energy-efficient fan filter units. Adds Fosnight, "Turbulent flow allows you to get to Class 5 and 6 while still providing sufficient airflow to remove the heat."
Automation, isolation commonplace
Fosnight further predicts that semiconductor fab owners will boost their level of automation over the next 10 years. "Today, in most fabs, operators move process lots between production tools. Even with 300-mm wafers, there are a fair number of operator moves," he says. "By 2013, automation hardware and software will surely be sufficiently mature and reliable to virtually eliminate the need for manual moves."
Meanwhile, cleanroom owners will increase their use of minienvironments and isolators for critical processes; and at the same time, resolve some of the operational problems with these enclosures—which, in 2003, included difficulty in obtaining low noise and vibration levels as well as tight temperature and humidity controls.
"Problems that are not evident today will be more readily visible with the use of independent monitoring systems in 2013," says Mark Hemingway, vice president of mechanical engineering at Sterling Engineering Co. Inc. (Sturbridge, Mass.). "Sensors, computers and software will monitor, identify, record and analyze critical data in the environment itself, independent of the building management system."
Nanotechnology will yield some of these monitoring systems, adds Ardmac's Murray. Extremely small monitoring devices will be designed and built directly into the product and processes as "continuous or selective monitoring mechanisms, incorporating the metrology to measure contaminants and their likely effects on the product or process."
In both the cleanroom and minienvironment, contamination monitoring will move from daily and hourly readings to instantaneous results in 10 years' time. "Instead of having to go to a testing facility after scanning the room or minienvironment, cleanroom users want real-time monitoring results," says O'Halloran. "Right now, there are some patented devices that can do real-time monitoring of particles and gases, but it will be a routine technology in 2013."
Intelligent monitors, say our panelists, will give engineers the ability to remotely control cleanrooms, even when they are on another continent. Instrumentation/control systems will let engineers make repairs and fixes from a remote location.
AMC and airflow modeling
While the first half-century of cleanroom evolution focused on the understanding and control of particle contamination, the next decade will target airborne molecular contamination (AMC). Influencing this trend is the development of nanometer-sized semiconductor devices, where AMC can cause corrosion. In the life sciences industries, biological contaminates, molds and viruses are the AMC concern.
That's why airflow modeling via computational fluid dynamics will prove essential to future cleanrooms, says Andy Solberg, an airflow management engineer with IDC. Airflow modeling can trace back to the source of an AMC release and predict migration patterns—in cleanrooms, isolators and minienvironments—and indicate appropriate filter placement.
In 10 years, airflow modeling will prove so accurate at predicting AMC behavior that rooms and enclosures will be modeled in advance of implementation. The user will go "directly to preset and prelocated filter solutions instead of wasting time and money on manual trial-and-error experimentation," says O'Halloran.
Airflow modeling will also be used to monitor the quality of the air outside the facility and indicate best locations for intake air—an urgent need in highly polluted areas of the world.
Multi-purpose AMC filtration
By themselves, HEPA and ULPA filters are worthless against AMC, which can require a different type of filtration media for each type of molecular contaminant. Whereas today it takes two separate filters to control acids and bases, the future of AMC filtration is a single, multi-purpose filter.
"The technology exists today to remove almost all of the different AMC of concern, but may involve multiple media types and control technologies [adsorption, absorption, chemisorption, oxidation, catalysis, etc.]. That could mean as many as six different stages of filtration," says Chris Muller, technical services manager at Purafil Inc. (Doraville, Ga.). "Manufacturers want a little black box they can put into their air handler. They also want to achieve and maintain higher removal efficiencies than are available today. It's about doing more with less, because they won't have space in the air handlers, or the pressure drops available, or the weight loading in the ceiling grid to accommodate the required level of air cleaning."
By 2013, cleanroom users will adopt a more holistic approach to this contamination problem. That means not only identifying specific AMC of concern, but all other molecular contaminants in the environment that might adversely affect overall AMC control. They will also formalize their efforts by dedicating full-time personnel to manage AMC control.
Muller also sees more emphasis on AMC filtration in tools, minienvironments and makeup air as opposed to the general air handling system. In addition, look for more filtration of process fluids, says Vijayakumar.
More lethal ESD
Down on the cleanroom floor, there will be even fewer personnel in 10 years. But that doesn't mean fewer electrostatic discharge (ESD) incidents. "As things get smaller in all areas of technology, the possibility for ESD damage increases," says Arnold Steinman, chief technology officer at ION Systems Inc. (Berkeley, Calif.).
For example, if by 2013 the semiconductor industry migrates to 32-nanometer devices, static sensitivity levels will sink to 10-15 volts as opposed to 250 volts today. "With such low-static voltages, preventing damage before it occurs will be key," says Steinman.
To further compound the problem, "we're replacing human handling with equipment and robotic handling, which can produce a lethal type of ESD event 10 times more damaging than human handling," says Stephen Halperin, president of the ESD Association (Rome, N.Y.) and president of Stephen Halperin and Associates Ltd. and Prostat Corp. (Bensenville, Ill.).
While the fundamentals of electrostatic control will not change, a greater preponderance of equipment, tools and materials will incorporate anti-static properties as a standard feature rather than a premium add-on. Users will assess and select raw materials, production aids and packaging materials based on their electrostatic control properties, then combine these materials with ESD monitors throughout the cleanroom to prevent damage.
"All of these product areas are going through a full evolution in terms of design, with the emphasis on preventing damage—not just responding to damage after it has occurred," says Halperin. "That makes the future fascinating from an ESD standpoint."
Shift in consumables
Basic consumables will incorporate more anti-static qualities over the next 10 years, but don't look for dramatic technological enhancements in this area. Instead, with fewer personnel in the cleanest of cleanrooms, consumption of cleanroom products will shift to new user groups working in less stringent conditions.
"The cleanest fabs will continue to use mats, but not as many as they did 10 years ago," says Dennis Baldwin, president of Purus International Inc. (Indio, Calif.). "Fewer bodies in the cleanroom will mean fewer mats used on the floor."
Mats, whether washable and reusable or peel-off and disposable, will remain in use in all applications because they offer both a physical barrier and a psychological entrance marker to the cleanroom. "Wherever you've got people involved in critical environments, there will always be a need for contamination-control flooring," explains Mark Dalziel, managing director of Dycem (Bristol, U.K.; Warwick, R.I.).
The polyester knit fabrics currently used in cleanroom wipes will continue to provide the best cost/performance tradeoff in 2013, says Howard Siegerman, director of marketing for ITW Texwipe (Upper Saddle River, N.J.). In semiconductor fabs, the most significant change over the next 10 years will be in how the wipes are used—less for environmental surfaces and more for process tools. Pharmaceutical applications, meanwhile, will require cleaner wipes and sterile, ready-to-use products, says Kathy Miscioscio, also a director of marketing for ITW Texwipe.
Looks will be deceiving
Ten years from today, cleanrooms will resemble remodeled retro-classic autos, sums up Willy Kohne, a senior mechanical engineer at IDC.
Kohne, who worked on his first cleanroom in 1972, says those future facilities "may look the same, but creative engineering will embed a lot more technology under the hood than people realize."
Sheila Galatowitsch, a special correspondent to CleanRooms magazine, is based in Denver, Colo. She can be reached at [email protected]