Tag Archives: Clean Rooms

By Hank Hogan

In the good old days-say, five years ago-shrinking semiconductor features meant contamination challenges due to eliminating smaller particles. However, as new materials are introduced at a rapid rate, that’s no longer the case. A look at lithography and back-end processing shows why this isn’t your father’s-or even your older brother’s-fabrication process and what that means for contamination control.

Larry Thompson, president of the consulting firm IPSSLP (Austin, TX), notes that the lithography critical dimension (CD) budget, like killer particles, tracks feature size. “Because that CD budget is shrinking, you have to have better and better control over the airborne contamination,” he says.

New materials, though, are now having an impact. Immersion lithography substitutes water for air between the last lens and the wafer, allowing finer imaging. However, contaminants in or under the resist can be struck by an intense laser, which could result in a bubble that scatters light and deposits volatiles nearby. Because of this, notes Thompson, companies are contemplating making the last lens a flat, replaceable element.

Now just being deployed, immersion lithography will someday play out. Extreme ultraviolet (EUV) lithography is a contender for the next imaging technology. EUV photons are about 13 nanometers wavelength, almost 15 times shorter than today’s state-of-the-art 193 nm. Producing those short wavelengths leads to a lot of particles, mainly in the tool itself.

An alternative involves imprinting, a technique in which a template with the desired features stamps out resist patterns. It allows very high resolution-if the mold is built correctly. Achieving that requires controlling contaminants, which is a significant challenge since the template is an exact reproduction and not a shrink as is the case currently. Contamination, “both airborne and in the material itself, [is] far more critical in imprint than in a 4X reduction,” says Thompson.

In back-end processing, new materials already can cause contamination. In an effort to boost circuit performance, manufacturers are turning to high-stress nitrides and oxides, along with low capacitance, or low-k, materials that are brittle and don’t adhere well.

Film stress is a problem, notes Chris Long, a senior engineer with IBM (Essex Junction, VT). “You take them through subsequent processing and at high-stress points…the film [starts] cracking and then popping off,” he says.

The problem occurs on wafers and tools. Exposed to varying humidity when the tool is opened for preventive maintenance, the film can form small airborne flakes. These can land on other tools, load ports, or elsewhere. Reducing airflow in a fab to save energy and money exacerbates the issue.

Ensuring that multiple tools spaced closely together aren’t opened at the same time can minimize the problem. Another solution might be to change tool cleaning procedures. Adding humidity control would also help, as would temporarily turning up area airflow.

Other new materials present their own contamination problems. Atomic layer deposition of a film, for example, offers great step coverage down microscopic trenches. However, it can also result in a nonuniform film on the back of a wafer, increasing potential backside contamination.

One solution is increased backside cleaning and inspection. A trend is for wafers to be divided into various cleanliness zones, including front and back.

Finally, Long notes the contamination impact will grow as feature sizes shrink below the current 65 nanometer state-of-the-art, requiring diligence in attacking such problems. “We may see issues if we don’t keep those [problems] on the radar screen and try to fix them ahead of time,” he says.

particles


November 1, 2006

compiled by Angela Godwin

DSM sells pharmaceutical production site

DSM Pharmaceutical Products, a Business Group of Royal DSM NV, has signed an agreement with Albemarle Corporation of Baton Rouge regarding the sale of the assets and business associated with DSM’s pharmaceutical production site in South Haven, MI., which is focused on the production of generic active pharmaceutical ingredients (APIs). “We are very pleased that through the transaction with Albemarle we have been able to secure the future of the site and to safeguard the employment of more than 100 of our people in South Haven”, says Leendert Staal, President of DSM Pharmaceutical Products. Terms of the deal were not disclosed.

Guidelines for modern ization of drug manufacturing

Last month, the Food and Drug Administration (FDA) issued a final guidance on quality systems, a set of formalized practices and procedures to ensure quality of human and veterinary drugs and human biological drug products during manufacturing. The guidance enhances FDA’s cGMP regulations. The document, “Quality Systems Approaches to Pharmaceutical Current Good Manufacturing Practice (cGMP) Regulations,” is expected to help manufacturers maintain consistent high quality and improve efficiency. It aims to demonstrate the benefits of incorporating modern quality principles-which should foster technical advancements-into manufacturing processes to better ensure the safety and efficacy of drugs for people and animals. Another goal of the guidance is to increase drug-production efficiency, which should help lower costs and prevent shortages of critical medicines due to manufacturing failures that can result in production stoppages and recalls. The full text of the guidance can be found at www.fda.gov/cder/guidance/7260fnl.htm.

EaglePicher Technologies, LLC (Inkster, MI; www.eaglepicher.com), a leading producer of batteries and energetic devices for the defense, space and commercial industries, and the City of Joplin, MO, announced the construction of a new 24,000-square-foot facility for the development and production of lithium-ion (Li-Ion) cells and batteries for U.S. military critical applications. The facility will be located in the Crossroads Industrial Park in Joplin, Missouri.

The new facility is being constructed by Crossland Construction Company, Inc. (Columbus, KS; www.crosslandconstruction.com) and will include dryrooms and cleanrooms fabricated by Scientific Climate Systems, Inc. (Houston, TX; www.dryrooms.com). The rooms will be used for critical process steps with dedicated air handling systems for each process. The facility will also have a full diagnostic laboratory on-site, paperless tracking of all cell and battery build and performance data, PLC capability and bar coding for all process steps. EaglePicher Technologies is investing over $10 million in the new facility.

The new building will be designed to maximize lean manufacturing and to minimize contamination risk. Internationally known independent laboratories will perform cell performance certification and environmental qualification. The facility will also include state-of-the-art security features.

Construction will be completed on or before December 29, 2006 and product production is expected to begin by the fourth quarter of 2007. EaglePicher expects up to 100 new high-tech employees in the facility within 3 to 5 years.

The Institute of Environmental Sciences and Technology (IEST) recently announced three scholarships for full-time students in the educational programs of science or engineering. A new scholarship in memory of Robert N. Hancock, a Fellow and Past President of IEST, long-time member of the Editorial Board of the Journal of the IEST, and a leader in the field of environmental engineering, is available. The Robert N. Hancock Memorial Scholarship, in the amount of $500, will be offered annually by IEST for the best original technical paper written by a student and published in the Journal of the IEST. The Eugene Borson Scholarship, in the amount of $500, is offered to a full-time high school senior, or undergraduate college or university student enrolled full-time in an accredited institution. Eugene (Gene) Borson was a Fellow of IEST, and was a leader in the field of aerospace environmental and contamination control engineering. Each applicant must submit a one-page essay describing his or her career goals and how IEST can help achieve these goals. A science, mathematics, or engineering faculty member must give a recommendation for each applicant. Finally, the Park Espenschade Memorial Scholarship, in the amount of $500, is offered by IEST for the best one-page essay on how IEST can help achieve your career goals. The Park Espenschade Education Fund was established to honor Park Espenschade’s enthusiasm, energy, devotion, and commitment to the education and training of young people in the environmental sciences. Each applicant must be recommended by a science, mathematics, or engineering faculty member, and be a full-time high-school senior, or undergraduate college or university student. For more information, visit the IEST Web site: www.iest.org.

With extensive industry feedback, the International SEMATECH Manufacturing Initiative (ISMI; http://ismi.sematech.org) has detailed the initial scope of its 300 mm Prime (300 Prime) effort, a strategy for improving 300 mm manufacturing productivity that draws on lessons learned from previous technology conversions, and recognizes the importance of collaboration, consensus-building, and compromise among chipmakers and equipment suppliers.

The ISMI program was launched in January and has subsequently involved discussions not only between ISMI member companies but with the industry in general. It now offers specific examples of how 300 Prime might be introduced in ways that encompass different levels of risk and investment. For example, a small-risk implementation might involve updating process tools with recipe and parameter management (RaP), a single wafer tool may replace a batch system for moderate risk, or implementation of a new high-speed factory-wide automated delivery system would represent higher risk.

Program Manager Tom Abell acknowledges that 300 Prime remains a work in progress, and actively encourages tool suppliers to become early contributors of ideas, skills and viewpoints through a set of advisory panels and discussions with ISMI. He characterizes 300 Prime as an evolutionary process scalable to 450 mm manufacturing, with timing dependent upon the possibilities that 300 Prime may hold. “Our view is that 300 Prime/450 mm transition should comprise a staged set of solutions that can be fine-tuned to a chipmaker’s particular business model,” he said.

A clear understanding of the scope of 300 Prime will enable the industry to make technology decisions to improve current productivity while ensuring a sound pathway for a future transition to larger wafers, Abell noted. These decisions range from issues on wafer thickness and carrier size to batch size, factory dimensions, wafer transport mechanisms, and standards for process control data.

To address these issues, ISMI has joined with SEMI (www.semi.org) to establish two engineering groups to collaboratively engage suppliers and chipmakers: the Manufacturing Technology Forum (MTF) and the Joint Productivity Working Group (JPWG). Inputs from both groups will help ISMI develop a 300 Prime capability assessment through 2006 and beyond.

According to Abell, ISMI will seek additional supplier views throughout the remainder of the year at key industry meetings around the globe, including a review of 2006 results and 2007 plans for 300 Prime and 450 mm during SEMICON Japan in Chiba, December 6-8.

The U.S. Food and Drug Administration (FDA) recently alerted the public to a voluntary recall being conducted by Perrigo Company (Perrigo) of Allegan, Michigan, for 383 lots of acetaminophen 500 mg caplets manufactured and distributed under various store brands. Metal fragments ranging in size from “microdots” to portions of wire 8 mm in length were found in about 200 caplets after 70 million caplets were passed through a metal detector. FDA is currently investigating the cause of the metal particles, but Perrigo originally informed FDA of the problem after discovering through its own regulatory quality control procedures that its tableting equipment was wearing down prematurely.

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Approximately 11 million bottles containing varying quantities of acetaminophen 500 mg caplets are affected by the recall. To date, no related illness or injuries have been reported and no consumer complaints have been received by the FDA or Perrigo. Based on information currently available, the FDA believes the probability of serious adverse health consequences is remote; however, swallowing an affected caplet could result in minor stomach discomfort and/or possible cuts to the mouth or throat. Consumers should consult their physician if they suspect they’ve been harmed by use of this product.

Consumers can determine whether they have a recalled product by locating the batch number printed on the container label. For a list of batches affected, visit www.fda.gov/oc/po/firmrecalls/perrigo/perrigobatchlist.html. A list of stores that carry store brands potentially affected by this recall is located on FDA’s Web site at www.fda.gov/oc/po/firmrecalls/perrigo/perrigocustlist.html.

According to a recent statement, FDA does not anticipate that this action will cause a shortage of acetaminophen.

The National Air Filtration Association (NAFA), the trade association for heating, ventilating and air conditioning air filter manufacturers and distributors around the world, has announced the recipients of the Clean Air Awards for 2006. The Clean Air Award is presented each year to building owners and managers that take steps to significantly improve the quality of their indoor air by increasing the level of air filter efficiency and improving the protocol involving indoor air quality components of their HVAC system in 10 categories. Recipients must accumulate a total of at least 52 combined points in the categories.

Candidates are nominated for the award by both NAFA members and members of the facility management community, and must submit detailed and specific steps taken towards cleaning the indoor environment. A NAFA Certified Air Filter Specialist then qualifies the submissions. Awards are judged by the NAFA Clean Air Award Committee and each recipient receives a custom designed trophy and recognition for their efforts.

This year, 21 organizations were recognized at the NAFA Annual Convention in September, including Toyoda Gosei Texas (TGTX). TGTX of San Antonio is a paint operations center and parts supplier for Toyota. The company was recognized for its three-stage make-up-air filtration system designed to remove particulates that might otherwise blemish or damage products manufactured by the company. TGTX installed prefilters of MERV 8 pleats, then MERV 11, MERV 13, and MERV 15 extended-surface pocket filters in series to remove particles prior to product coating.

For more information on the award and recipients, visit www.nafahq.org.

BSafE Innovations Inc. (BSafE), a joint venture company dedicated to veterinary applications of prion research, has announced preliminary findings from its most recent testing. Utilizing proprietary technologies developed by Pathogen Removal and Diagnostic Technologies Inc. (PRDT), which were used to develop the first human prion blood filter, PRDT scientists have been working on behalf of BSafE to demonstrate that the technology can be adapted to specifically target the bovine form of prions. Recent experiments have confirmed that the proprietary technology greatly enhances the sensitivity of post mortem testing for mad cow disease.

“These initial results are very encouraging and could enable the detection of mad cow disease in much younger animals and at much earlier stages of the disease to improve the safety of the food chain,” said Christian Frayssignes, president and CEO of BSafE.

Further testing is underway to replicate the experiments under different conditions. BSafE’s first objective is to provide the beef industry with a reliable and simple way to further improve the sensitivity of the current standard tests. Ultimately, the company believes it will be possible to detect the disease from a simple blood sample.

Understanding the wiping application enables cleanroom professionals to select the optimum wiper for their task

By Kimberly Dennis MacDougall, Kimberly-Clark Professional

Cleanrooms today need to be cleaner than ever. As a result, contamination and quality controls have become stricter and more complex. One example of this trend is the way cleanroom professionals now use wipers when cleaning. In the past, cleanroom wipers were used primarily to absorb spills and for general cleaning. Today, cleanroom wipers are engineered to accomplish those tasks and many more.


In the past, cleanroom wipers were used primarily to absorb spills and for general cleaning. Today, cleanroom wipers are engineered to accomplish those tasks and many more.
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Advanced wiper technology offers both performance and physical attributes to meet specific cleanroom needs. By carefully understanding and comparing the requirements of the wiping application (what the wiper needs to do) with the ability of the wiper to meet those requirements, cleanroom professionals will be in a position to select the optimum wiper for their task.

Wiper material and technology selection

For most cleanroom environments, synthetic fibers and blends are the materials of choice. The development and expansion of polymer technology, including polypropylene, polyester, and polyethylene, have improved to meet the ever-restricting requirements for cleanroom wipers. In combination with manufacturing process advancements (such as surface treatments that help make wipers more hydrophilic), these technological achievements have led to the development of new fabrics for use in wiper base sheets. In many ways, these new fabrics provide superior performance compared to traditional textile alternatives. Step-change advances in attributes such as purity and absorbency have become critical in the development of materials suitable for state-of-the-art cleanrooms.

Purity and extractables

The materials used to create a cleanroom wiper base sheet affect the wiper’s physical properties and performance. In cleanrooms, it is important for wipers to work without leaving residuals, which are materials or chemical residues originating from the wiping substrate that remain behind on a surface after wiping. Residuals can be divided into solid particles, classified as “lint,” and chemical elemental components, labeled as “extractables.”

Solid particles, or lint, are commonly quantified by measuring particles collected in fluid when the wiper is saturated and subjected to mechanical energy (agitation) to simulate use. This practice is known as a biaxial shake lint test, and it measures the number of particulates greater than 0.5 micron in size collected from the wiper in the fluid. Another way to evaluate lint is to measure the particles released into the air in response to mechanical energy input (flexing or twisting). The particles are usually quantified by weight or through automated counting of particles per unit of air. When the counting is completed, the particle sizes are also measured and grouped by size distribution. In general, a wiper made of 100 percent synthetic material will provide lower particulates than cellulose-based wipers because the synthetic single-filament fibers are less likely to shed.

Extractables are the second residual contaminant of concern in cleanrooms. These elemental materials-such as sodium, potassium and chloride-can be leached out of both disposable and woven wipers by solvents or other fluids being used on the wiper. They are subsequently deposited on the surface being cleaned or prepped. Elemental materials can cause various issues in cleanrooms: Electronics can be affected, corrosion can occur, and defects can be caused by ion transfer to critical surfaces. To avoid any of these issues, it is important to evaluate wipers for extractables with various solvents prior to purchasing. Normally, extractables data are provided for both water and a solvent, such as isopropyl alcohol (IPA). Cleanroom wipers made of synthetic fibers that are thermally bonded or are woven using processes that avoid glues, surfactants, binders or other additives typically have low extractables.

When evaluating different cleanroom wiper options, be sure to ask for test results from an independent laboratory that follows a recognized testing protocol, such as the IES-RP-CC004, Evaluating Wiping Materials Used in Cleanrooms and other Controlled Environments, from the Institute of Environmental Sciences.

Absorbency and residual fluid

As discussed above, because disposable cleanroom wipers are used to absorb fluid spills, they must be absorbent and have the ability to wipe a surface clean without leaving a residue and without generating lint particles and extractables that can contaminate the cleanroom.

Traditional test methods to measure the absorbent characteristics of cleanroom wipers include:

Dynamic wiping efficiency (DWE): This test method measures both the dry weight of a wiper and its weight after being manually pulled through a liquid insult at a predetermined speed. These two measurements, along with the density of the liquid and the volume of the insult, are used to calculate wiping efficiency. Because the wiping motion is performed manually, slight variances in wiping speed and method among different testers can lead to variable test results. Test results also do not give any indication of how the fluid is distributed on the surface after the wiping motion has been completed. Therefore, while DWE is a good indicator of the absorbent capacity of the wiper, it does not accurately represent a wiper’s ability to retain fluid and leave the surface free of residue.

Absorbent capacity and rate: This method, as measured by IEST-RP-CC004.3, places a wiper in a tray containing a selected liquid and allows the wiper to absorb as much of that liquid as possible. Once the wiper has absorbed to its full capacity, it is removed from the tray and suspended to allow excess liquid to drip into the tray. After 60 seconds of suspension, the mass of the wetted wiper is recorded. This measurement, along with the dry mass of the wiper, area of the wiper, and density of the liquid, can be used to calculate the absorbent capacity per unit area of the wiper. This method is sufficient for determining how much liquid the wiper can hold. However, the wiper is stationary throughout the test procedure, and therefore, the method does not indicate how the wiper would handle the fluid insult in a real-world wiping application. The second portion of this method tests the rate of absorption, measured by recording the time required for the disappearance of a drop of water dispensed onto the wiper from a fixed height. Again, while this method allows one to determine how quickly the wiper absorbs liquid, it does not address the wiper’s ability to remove fluid residue from the wiped surface.

A new test method has been introduced which is specifically designed to measure the residual fluid left on the surface after wiping:

Clean wiping efficiency test method: This test is more closely representative of the wiper’s actual use in a cleanroom. It displays a greater consistency in measuring the performance of a wiper and minimizes tester error. In the test, a wiper sample is quarter-folded and mounted so the folded edge is the first to come in contact with the surface to be wiped. A specified volume of fluid containing a fluorescent solution is applied to the wiping surface through a fixed syringe applicator. The system is then enclosed and the wiper is passed over the rotating wiping surface using a traverse arm, in a steady and fixed rate while applying a specified pressure. The moment the test movement is stopped, the remaining fluid on the platter is quantified via ultraviolet light and a computerized imaging system. The image is then analyzed to calculate the area of the surface that is free of the fluorescent solution, which is recorded in square centimeters.

The right wiper for the task

Choosing the right wiper for the task is a function of understanding a number of variables that can exist in a cleanroom, including:

the contaminant you are cleaning from the surface

the nature of any chemicals you are cleaning with or applying to the surface

the nature of the surface being wiped (texture, electrical properties, sensitivity, etc.)

the duration of the task (single-use or extended/multiple-use)

the risk involved (if work in progress is damaged)

the specific objective of the wiping task (what you want to accomplish by wiping the surface)


Because disposable cleanroom wipers are used to absorb fluid spills, they must be absorbent and have the ability to wipe a surface clean without leaving a residue and without generating lint particles and extractables that can contaminate the cleanroom.
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Cleanroom environments have very specific requirements in terms of the number of particles (equal to or larger than 0.5 micron in size) that can be present in the air. For example, under the old Federal Standard 209 classification system, a Class 10 cleanroom could have only 10 particles equal to or larger than 0.5 micron per cubic foot of air. Today, those limits are equivalent to those in an ISO 4 cleanroom. It is therefore crucial that wipers selected for any class of cleanroom be thoroughly assessed to understand their ability to minimize lint generation.

For cleanroom environments, the choice of wiper will generally be from one of the following base sheet options:

Woven: Usually made with 100 percent continuous filament double-knit polyester fibers, these wipers are most suited for high-end cleanroom applications. Some wipers in this class offer sealed edges, low linting and other attributes like controlled extractables and low ion contamination, as well as solvent and abrasion resistance, which are needed in ISO 3 and cleaner cleanrooms.

Spunlace: Usually made with polyester and cellulose, but sometimes made with a blend of rayon and polyester, these cloth-like wipers are ideal for higher classification cleanrooms, for virtually any surface cleaning/preparation task (with water and/or solvents). These materials are hydrophilic and offer fast absorption of water, solvents, bio fluids, and oil/grease. As with meltblown-based wipers, some spunlace wipers may be packaged specifically for use in controlled cleanrooms, while other versions are designed for use in clean manufacturing environments.

Meltblown: Usually made from polypropylene, these wipers are ideal for virtually any surface cleaning/preparation task or for use as surface liners. These wipers offer better resistance to acids, bases and solvents than many other wiping materials, while providing low extractables. Some meltblown-based wipers may be used for critical tasks in certain classes of cleanrooms, while others are designed for use in clean manufacturing environments. Meltblown-based wipers are also excellent for surface preparation tasks, due to their ability to efficiently carry and release solvents to surfaces. Because of their chemical resistance, meltblown base sheets are also commonly used for presaturated wipes.

In addition to absorbency and the other performance factors listed above, other questions for the selection process include:

Can the wiper be sterilized? While it is preferable to use a wiper that is sterile “out-of-the-box,” some users may want the option of sterilizing on premises using their existing equipment. If that’s the case, make sure the wiper can stand up to high temperatures (up to 280°F).

Will the wiper be used in contact with pharmaceutical, biotechnology or medical products? If so, it may need to meet the contact-safe requirements of the U.S. Food and Drug Administration (FDA). Some meltblown-based wipers (made of polypropylene) that contain no glues or binders meet USDA requirements for food processing establishments.

Is absorbency the most important attribute? If it is, look for wipers that absorb liquids on contact while still delivering low particle and extractables levels. Or, if the wiper is being used to deposit a solution to prepare a surface, perhaps fluid release is the more critical attribute. Here, you’ll want to make sure the wiper stands up to commonly used cleanroom solvents and releases few extractables when wet.

How durable is the wiper? A continuous filament fiber can provide an outer surface that helps to impart a high level of strength and durability, as well as a clothlike feel. However, if the expectation for the duration of use is minimal (single pass), a lighter weight, less durable wiper may meet the user’s needs.

What is the edge finish of the wiper? Some wipers have a sealed-seam edge as a result of passing the wiper through an ultrasonic welding device. About 1⁄4 inch around the outer edge of the product is melted together. This reduces lint, but it also makes the outer edge of the wiper non-absorbent and very harsh to the touch. Scratching from the edges may also be an issue. Other wipers use laser-sealed seaming technology to fuse the ends of the fiber bundles. This technology reduces the possibility of lint while leaving the entire wiper able to absorb to its capacity without the complication of dealing with a thick, harsh edge.

Are the wipers available in different packaging formats to meet various needs throughout the facility? If so, does the packaging properly protect the wipers from in-transit contamination and from static build-up during the dispensing process? Does the packaging allow the product to be conveyed in such a way that it arrives uncontaminated to the clean environment? Double-bag packaging helps to protect the wipers from static and other contaminants during transit and storage.

Is the wiper going to be used with a common solvent like isopropyl alcohol? Consider moving to a one-step application using a resealable, presaturated wiping product. Commonly available, these wipers are typically presaturated with a 70 percent isopropyl alcohol/30 percent deionized water solution.

Do you need to disinfect and/or sanitize surfaces? Make sure the base sheet is compatible with bleach and/or quaternary amine disinfectants and provides the highest possible levels of actives concentration during prolonged periods of use.

Conclusion

Cleanroom wipers can be highly designed, sophisticated tools capable of significantly improving processing, quality and contamination control. To select the correct wiper for cleanroom environments, use the information discussed here to be sure the wiper meets your needs. For more information on cleanroom wipers, visit www.kimtech.com.


Kimberly Dennis MacDougall is a research scientist with Kimberly-Clark Professional (Roswell, GA). She can be reached at [email protected].

Keeping research clean


November 1, 2006

Innovative cleanroom use helps cut time, money from product development cycles

By Sarah Fister Gale

The time it takes to transform a brilliant idea into a marketable product determines a company’s profitability, which means managers in every industry are searching for ways to cut time and money from their product development timelines. One of the many solutions they’ve hit upon is putting cleanroom facilities inside and next to research labs, giving scientists the opportunity to create, test and tweak in a clean environment-bringing them ever closer to their end goal of a finished product.

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This shift in the use of cleanrooms is part of a transition from basic research to more specific scientific applications, says Tom Mistretta, senior laboratory planner for CUH2A in Princeton, NJ. “It’s no longer enough for scientists to say ‘we understand how a new process works.’ Now they have to be focused on how that process can be applied to commercial products.”

It also means that scientists from multiple disciplines need facilities where they can work simultaneously on joint projects, combining their unique research and sciences together into finished products, such as biomedical or bionanotechnology devices.

“Scientific research is becoming more interdisciplinary, which means lab spaces need to accommodate multiple users,” Mistretta says.

The trend toward multidisciplinary cleanrooms for research is translating into new opportunities for cleanroom designers and equipment manufacturers, who are seeing a greater demand for both portable and permanent cleanroom spaces in university labs, research firms, pharmaceutical development houses-anywhere that a product is being created that may someday require the controlled atmosphere of a cleanroom environment.

“When researchers are focused on the commercial viability of their outcomes, they need an environment that is akin to a production facility [in which] to do their work,” says Pete Daniele, president of LM Air Technology, in Rahway, NJ. “They have to ensure a clean environment to be sure their results aren’t tainted.”

Birck Center sits on the cutting edge

No one understands this need better than John Weaver, facility manager at the Birck Nanotechnology Center. This state-of-the-art, 187,000-square-foot scientific research facility at Purdue University (West Lafayette, IN) was designed specifically to bring experts from different disciplines together under one roof where they can collaborate, share ideas, and transform the principles of nanotech design into marketable products and solutions for real-world problems.

“We are just beginning to explore nanotech research and development and we don’t know where it’s going to take us,” Weaver says, noting that the multidisciplinary design of the Birck Center, which includes shared lab and cleanroom spaces, increases opportunities for interaction among all of the disciplines. “It enables research that will speed our understanding of nanotechnology.”

Scientists, engineers, academics and administrators from academia, government and industry are invited to take advantage of the $58-million-dollar complex, which features more than 22,000 square feet of laboratory space, including special low-vibration rooms for nanostructures research, with temperature control to less than 0.1°C. Other laboratories in the building are specialized for nanophotonics, crystal growth, bionanotechnology, molecular electronics, MEMS and NEMS, surface analysis, SEM/TEM, electrical characterization, RF systems, instruction and training, and precision micromachining.

At the center of the facility is a state-of-the-art, 25,000-square-foot, Class 10-100-1,000 (ISO 3-4-5) nanofabrication cleanroom, part of which is configured as a biomolecular cleanroom with a biological-pharmaceutical-grade environment needed for work with pathogen-detecting biochips and other biological nanotechnology.

The cleanroom has a bay-and-chase layout, which is less common than a ballroom configuration, because the initial and operation costs were much lower, Weaver says. “The conditioned air in the cleanroom returns through the chase, so the chase air is free,” he explains. Each of the 13 cleanroom spaces, which open off of the central spine, are configured to ISO 3, 4, or 5. The cleanroom space features sheet-vinyl flooring, coved corners, pharmaceutical-grade floors, walls and ceilings, and a Hunt Air fan wall system. “The fan wall is very helpful to us because the fans are all man-liftable and pop in and out so we don’t need devices to lift or replace them,” Weaver says. The wall has six fans per unit, but five can run the system effectively, creating a cushion for equipment failure. “We keep a couple of fans on a shelf for back up.”


Figure 1. A sterile pass-through chamber, such as the one shown here, allows researchers to pass materials or work without having to leave their cleanroom space and regown. This pass-through features continuous-seam welds with coved corners that eliminate particle traps and simplify cleaning. Courtesy of Terra Universal.
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Each space has a separate entry, gowning areas and isolated airflow, and there are sterile pass-through chambers and glove boxes between the rooms where researchers from either side can pass materials or work without having to leave their cleanroom space and regown (see Fig. 1).

It is the first such blended cleanroom design and creates unique opportunities for scientists to work simultaneously in separate, specialized cleanrooms or to move back and forth between cleanroom spaces and lab spaces.

“We look at the cleanroom more for enabling purposes,” says Weaver. “Some people don’t believe you need cleanrooms in a research setting, but when it comes to airborne molecular contamination, you have to have a clean environment so as not to confound your research or produce misleading or clouded results.”

The cleanroom space also includes state-of-the-art equipment for research, including a Leica Vector Beam photolithography system to create nanoscale patterns on wafers with an electron beam; an optical pattern generator, donated by Raytheon Co., that creates photo masks for patterning silicon wafers; and six furnaces, donated by LSI Logic Corp., that achieve temperatures of up to 1,200°C to alter the electrical characteristics, or conductivity, in specific areas of the silicon wafer.

The hope is that by creating spaces where scientists can collaborate using this cutting edge facility and equipment they will hasten advances in nanotech research, Weaver says. It’s already seen some success toward this end in a project called “Lab on a Chip,” a Listeria monocytogenes bacteria detection device that was one of the first projects conducted in the Birck Center cleanroom. The biochip combines bioMEMS and bionanotechnology elements to create a micro-integrated system that can be used to detect the dangerous and deadly bacteria in food-processing operations.

Because the cleanroom spaces at the Birck Center are linked, the project team was able to create the MEMS elements in the semiconductor fab then pass the device through an isolated air-locked chamber to the biocleanroom, where they added the active biological species material to the chip without ever breaking the clean environment.

“Before we had the Birck Center, this research was done in three different buildings,” says Rachid Bashir, a nanobiologist at Purdue who is working on the Lab on a Chip project. “This building is a dramatic improvement, not just because it speeds things up, but because it enhances our understanding.”

From universities to machine shops

While the Birck Center is on the leading edge of high-tech cleanrooms, LM Air has been accommodating a growing demand for the design and installation of cleanroom spaces from universities and research centers, including a 1,100-square-foot hardwall cleanroom for Rutgers University (Piscataway, NJ). This recirculating cleanroom project included an epoxy floor, separate gown room, electrical, lighting, HEPA-filtered modules and the internal cleanroom equipment (see Fig. 2). It was a turnkey application that included three separate rooms, one of which had clear, acrylic wall panels (see Fig. 3).


Figure 2. LM Air handled the design and installation of a 1,100-square-foot hardwall cleanroom for Rutgers University. Courtesy of LM Air Technology.
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The company has completed similar projects for a number of universities, including the University of California-Los Angeles, the University of Maryland (College Park, MD), and the University of Arizona (Tucson, AZ).


Figure 3. This turnkey project included three separate rooms, one of which had clear, acrylic wall panels. Courtesy of LM Air Technology.
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LM Air has also seen demand for cleanrooms growing in less conventional cleanroom industries. For example, it recently installed a 16-foot x 10-foot, soft-sided, portable cleanroom in the warehouse of a Bayer aspirin facility to be used as a quality control booth where drums of product are dropped in, sampled, and removed. It completed a similar project in the machine shop of a steel foundry, creating a clean space where facility operators could manufacture steel wire (see Fig. 4).


Figure 4. There’s a growing demand for cleanrooms in less conventional cleanroom industries, including this project in the machine shop of a steel foundry. The goal was to create a clean space where facility operators could manufacture steel wire. Courtesy of LM Air Technology.
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“We are seeing a lot more broad-based need for cleanrooms in every industry,” Daniele says.

That demand will only increase as companies continue to try to short circuit the path to product development. “We are seeing the number of cleanrooms in labs growing in every industry,” Mistretta says. “If you can get to the pilot level in the lab, you can cut two years from your development cycle. Cleanrooms are a part of that.”

Shortening the time to market is only one of the benefits of having a cleanroom in the research lab. It also enables scientists to make immediate adjustments in response to changing needs or environmental issues; or to customize products, such as gene therapies in hospitals for patients on the spot. “When you have cleanrooms in the facility, there is much more immediate interaction between developers and users,” he says.

Cleanrooms that fit like a mitten

Designing these kinds of multidisciplinary research-based cleanrooms and labs is far different from building conventional cleanrooms that are planned for specific tasks, Mistretta points out. “They require more flexible spaces that can accommodate a greater variety of activities, and usually include portable equipment and furniture, and increased power availability and data connections to servers or local networks so that operators can download data off equipment onto their systems and add or change out equipment as necessary.”

Mistretta notes that, although clients in some industries still want cleanrooms that fit like a glove (sleek, carefully laid out, and designed for very specific uses), more often, new facility operators are prioritizing open spaces with room to expand. They need flexibility so they can change the way the space functions, but they don’t have the budgets to build huge cleanrooms that can accommodate any and all potential future tasks.

Mistretta likens these spaces to mittens: “They fit around your basic need, but leave you room to ‘make a fist’ or extend out.”

While not huge, these cleanrooms tend to be more open, with air handling systems that are designed to increase capacity or air quality as changes arise. “When making design decisions for these types of spaces, clients need ask themselves: Will I need to add fume hoods in the future? Do I have enough air circulation? Enough fan filter unit capacity? Enough duct work?” Mistretta says. “Open lab designs are more forgiving in these respects.”

Making the right choices to accommodate future flexibility with current costs isn’t easy he says. “Finding harmony between budget and what you want to do with the space is the magic of cleanroom design. That’s what we do.”

Full of hot air

When designing multidisciplinary spaces that must accommodate a host of different users and uses, operators must also factor rising fuel costs into their design decisions.

“The increasing amount of equipment and PCs in cleanroom spaces is generating a lot of heat, and the air conditioning system needs to accommodate that,” says Mistretta. “We are seeing more ventilation in these rooms than we saw 20 years ago.”

The problem, he says, is that venting all of the hot air out of the building is a waste of money, especially with soaring heating costs. “You don’t want to exhaust cleanroom air that you’ve conditioned to a high level of purity.”

This has caused a growing interest in heat exchange systems, which capture exhausted heat on heat wheels, plates, or pipes, and reuse it to heat incoming air to the facility. In some states, facilities can even receive fuel credits for their heat recovery systems to further offset energy costs.

“You have to look at these solutions carefully, however,” warns Michael Buckwalter, publications director for Terra Universal (Fullerton, CA), noting that operations must avoid reusing any air contaminated with fumes or toxic chemicals from the processing operation.

Along with heat recovery systems Mistretta has seen a lot of operations building larger equipment into the walls from the outside, so that heat and noise can be exhausted into the service corridors where the air is not as conditioned. “It’s another way to get the undesirable effects outside the room, and it creates more space inside the room.”

Besides fuel costs, operators are tightening their exhaust systems in response to increases in air quality and environmental safety standards relating to environmental issues from cleanroom operations.

One of the most well-known standards in this arena is the Leadership in Energy and Environmental Design (LEED) rating program for new construction and retrofit projects from the U.S. Green Building Council, a coalition of leaders across the building industry. The LEED rating system is a nationally accepted benchmark for the design, construction, and operation of high-performance green buildings, assessing performance in five key areas of human and environmental health: sustainable site development, water savings, energy efficiency, materials selection, and indoor environmental quality.

Some cleanroom equipment manufactur-ers are also pursuing green standard status, particularly by seeking Building Green certification for their products, which allows them to be listed in the GreenSpec product information service listing of environmentally preferable building products. The directory is available to architects and engineers searching for products to attain LEED credits for their building designs.

“Nationally the response has not been as quick as it should be,” says Mistretta, but he is optimistic that more communities will adopt tighter regulations for air quality as programs like LEED gain acceptance nationwide. “Every time you cross one hurdle, you wonder what you can do next to make it better, safer, or cheaper.”

Cleanroom in a box

For many facilities, ‘cheaper’ is a significant requirement. Tightened standards, increased quality control demands, and speed to market are pushing many industries to upgrade facilities, adding cleanrooms where they weren’t previously necessary or increasing the cleanliness of the existing environment, says Terra Universal’s Buckwalter. However, permanent cleanroom spaces don’t always make sense. For those facilities that have limited space and tight budgets, or that handle low-run or limited-lifespan products, portable cleanrooms are less expensive and more flexible (see Fig. 5).


Figure 5. For facilities that have limited space and tight budgets, or that handle low-run or limited-lifespan products, portable cleanrooms-such as the BioSafe Cleanroom shown here-are less expensive and more flexible. Courtesy of Terra Unviersal.
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While in the past choosing modular spaces wasn’t always feasible for certain industries, recent advances in hardwall modular cleanroom spaces are making portable rooms a viable economical option even for the most rigorous cleanroom operations requiring increased durability.

Buckwalter says that many of Terra’s clients are demanding more features from modular spaces, such as coved corners, walls and ceilings; microbial inhibitors for easier cleaning and sterilizing; aseptic and conditioning pass-through chambers; and a lot more stainless steel.

“Stainless-steel rooms meet requirements that plastic rooms just can’t,” he says. “They stand up to harsh disinfectants and feature rounded corners and smooth surfaces that are faster and easier to clean.”


Figure 6. The BioSafe cleanroom in stainless steel features smooth surfaces, inside and out, that can tolerate standard disinfectants and sterilization procedures and can also be specified with antimicrobial surface coatings. Shown with pass-through chambers and A/C modules. Courtesy of Terra Universal.
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To accommodate these requests, Terra Universal now offers an all-steel BioSafe Cleanroom, featuring smooth surfaces, inside and out, that can tolerate standard disinfectants and sterilization procedures and can also be specified with antimicrobial surface coatings (see Fig. 6).

“The BioSafe Cleanroom has a rigid, self-supporting structure without a separate frame or external bracing-a key advantage over other designs that require special permitting and contractor installation,” Buckwalter says.

The ceiling grid of the BioSafe room features bays for installation of HEPA or ULPA filter/fan units and lights, or optional UV sterilization and fluorescence detection modules. The rooms accommodate the full range of cleanroom configuration options, including air conditioning, dehumidification modules, and ventilation equipment. Double-wall panels create an installation zone for electrical conduit, gas and vacuum service lines, which can be insulated to optimize thermal stability and reduce energy costs.

He estimates that the portable room costs 10 times less than a fixed installation, and says that it can be built to spec and operational in two months. “BioSafe is a lot more economical than a fixed cleanroom and clients don’t have to sacrifice ruggedness.”

Terra’s hardwall modular system is currently being used in a revolutionary project that could become a model for companies seeking ways to improve quality control over projects outsourced overseas. The project involves a company that is developing a cancer therapy, which needs to be manufactured in a cleanroom comprising four suites, each requiring unique air pressure differentials and cleanroom ratings. To ensure the high-est quality control standards at the franchised offshore manufacturing sites, it created a model manufacturing environment using Terra’s BioSafe Cleanroom, ensuring that each operation use the exact same equipment, environment and specifications. “By using the model cleanroom, the company is able to control the production environment based on tested designs and processes,” Buckwalter explains. “It enables them to have all the advantages of a fixed room, without the cost.”

Whether a cleanroom is part of a state-of-the-art facility or is a lean, portable space designed for efficiency and cost effectiveness, fuel costs and environmental issues will continue to be a priority concern as operators look for ways to shave time and money from their product development process while giving their developers the space and tools they need to create the “next best thing.”

“When you work at a company, you share a single mission-to be successful,” Mistretta says. “We’re seeing our clients making certain investments in their infrastructure and their processes to accommodate that.”