Tag Archives: Clean Rooms

January 25, 2007 — /IEST/ — ROLLING MEADOWS, IL — Registrants will receive a complimentary copy of IEST-RP-CC023.3: Microorganisms in Cleanrooms with their attendance at the Institute of Environmental Sciences and Technology (IEST) online education class “Biocontamination Control — An Applicable Approach.” The course will be presented on Wednesday, February 21, 2007 at 11:00 a.m. (CST). Learn from your desk, conference room, or auditorium without travel expenses. The per-location fee has no limit on the number of students who may participate at each location.*

This online tutorial will present a general approach to biocontamination control that can be adapted by various industries based on the critical requirements of specific products or processes. The session will explain how to perform microbial environmental monitoring and interpret the data. Reference documents will include the ISO 14698 series of International Standards: Cleanrooms and associated controlled environments — Biocontamination control, and IEST-RP-CC023.2: Microorganisms in Cleanrooms.

Instructor Gordon M. Ely is QC/Validation Manager at Nelson Laboratories, where he has worked for more than 16 years. Ely is a certified Specialist Microbiologist (SM) in Consumer and Industrial Microbiology and a Registered Microbiologist (RM). He is a member of IEST, AAMI, and ASTM and involved on various working groups within these organizations, as well as a US delegate for working groups within ISO/TC 198 and ISO/TC 209. Ely is the current President of IEST.

More information is available online at www.iest.org or by calling IEST at (847) 255-1561.

* Access will be granted to one computer per location.

Founded in 1953, IEST is an international technical society of engineers, scientists, and educators that serves its members and the industries they represent (simulating, testing, controlling, and teaching the environments of earth and space) through education and the development of recommended practices and standards.

IEST is an ANSI-accredited standards-developing organization; Secretariat of ISO/TC 209 Cleanrooms and associated controlled environments; Administrator of the ANSI-accredited US TAG to ISO/TC 209; Administrator of the ANSI-accredited US TAG to ISO/TC 142 Cleaning equipment for air and other gases; and a founding member of the ANSI-accredited US TAG to ISO/TC 229 Nanotechnologies.

Serving myriad functions, new building set to increase productivity and enhance customer support capabilities

January 31, 2007 — /PRNewswire/ — OYAMA, Japan — Gigaphoton Inc., a major lithography light source manufacturer for the global semiconductor industry, announced today that it has completed construction of a new building at its headquarters campus. Slated to open February 1, this new facility will house a state-of-the-art, Class 1,000 cleanroom that features expanded research and development capabilities and laser light source maintenance training for field service engineers. With training and R&D transitioned to the new facility, the existing building will now be fully dedicated to production of Gigaphoton’s advanced laser systems. This will enable Gigaphoton to nearly double its manufacturing capability as early as April.

In addition to the expanded cleanroom area for research and development activities, the training facilities have increased significantly. This expansion investment will allow Gigaphoton to further augment its already high-quality customer support capabilities to address its growing installed base. The new facility will also house Gigaphoton’s customer support administrative functions, as well as a spare parts warehouse.

Known for their extremely high reliability and lower cost of ownership, Gigaphoton’s laser light sources are widely used by most of the world’s major chipmakers. Over the past four years, Gigaphoton has dramatically increased its market share — capturing 30 percent of the global market for laser light sources (based on number of units sold) in 2006, according to company data. This is due to its popular “G41K” series krypton fluoride (KrF) laser units, which are installed in the mass-production factories of the world’s leading semiconductor manufacturers, as well as its GigaTwin series, a twin-chamber argon fluoride (ArF) laser. Gigaphoton reports that the number of GigaTwin units shipped has doubled every 6 months since the product’s introduction in 2005.

According to Dr. Yuji Watanabe, president and representative director of Gigaphoton, increased demand for its advanced light sources led the company to expand its existing facilities. “Gigaphoton’s high-quality, extremely reliable, and high-uptime products enable chipmakers’ fabs to run at benchmark levels. As a result, customers continue to turn to us as they realize the benefits afforded by our advanced lithography light source solutions, for which we provide superior service and support. All of this, together with our newly expanded production capabilities, will position us to capture a larger share of the excimer light source market over the next few years.”

About Gigaphoton
Gigaphoton Inc. was founded in 2000 as a joint venture of Komatsu Ltd., the world’s No. 2 construction machinery manufacturer, and Ushio Inc., the world’s No. 1 lithography lamp manufacturer. Since then, Gigaphoton has been developing and marketing user-friendly, highly innovative laser light sources that make a great contribution to lithography technology so as to meet the stringent requirements of the ultra-fine circuit patterns of the gigabit era, and is delivering them to major lithography tool suppliers in the global semiconductor industry. As the world’s no. 2 excimer laser light source manufacturer, Gigaphoton holds a strong position in Asian market, including Japan, while also continuing to enjoy rapid growth in the U.S. and European markets. More information about Gigaphoton can be found on the company’s website at http://www.gigaphoton.com/ .

The company name, logo, and designations GT40A, GT60A, and GT61A are trademarks of Gigaphoton, Inc. The content of this release may be revised without prior notice. Gigaphoton shall not be liable for updating or announcing a correction if the content of this release is changed for any reason in the future.

Source: Gigaphoton Inc.

CONTACT:
Hideichi Satou, +81-285-28-8410, or fax, +81-285-28-8439, or [email protected]

Yutatsu Matsui, +81-285-28-8415, or fax +81-285-28-8439, or [email protected]

Marie Labrie of MCA, +1-650-968-8900, or fax, +1-650-968-8990, or [email protected]

Web site: http://www.gigaphoton.com/

By Hank Hogan

When it comes to next-generation lithography, the semiconductor industry may be doing a double take-and that could mean double duty for contamination control. There’s concern within the industry about a lithography shortfall when the 32-nanometer half-pitch node enters production in about five years. Doubts have arisen that the leading contender, extreme ultraviolet lithography (EUVL), will be ready in time.

To counter this, technologists are considering double patterning, in which only part of the pattern is imaged and etched on the first pass. A second pass takes care of the rest. By splitting up the lithography process, the achievable minimum pitch is decreased without having to use a shorter imaging wavelength or make other changes (see Figure).

“You’re basically using what’s available today-no new materials. Everything is more or less standard,” says Kurt Ronse, director of the lithography department at the nanotechnology and nanoelectronics research center, IMEC (Leuven, Belgium).

Although double patterning does require a stringent overlay tolerance between the two halves, Ronse notes that achieving this doesn’t require new fundamental research and development. Also, because future lithography processes will need to attain tight overlays anyway, hitting the specification required for double patterning will be required no matter what lithography technique is used.

The downside of double patterning is twofold. First, the most critical layers must go through lithography and etch twice, which cuts throughput. Second, there could be a yield hit. Two passes, plus extra handling, means doubling the chance of picking up a particulate, contaminant or other killer defect. Hence, double patterning will demand an even greater emphasis on contamination control in the most sensitive parts of the manufacturing process.

As a result, double patterning could be both the easiest way to achieve 32 nm manufacturing and the most expensive, at least for volume production. Thus, it may only be practical for the initial ramp up, which could start in two to three years.

As for EUVL, Michael Lercel, director of lithography for the research consortium SEMATECH (Austin, TX), says there has in fact been progress. In November, SEMATECH engineers reported shipping and handling lithography masks without adding defects. They also reported developing an integrated smoothing and deposition process to make more perfect mask blanks, a fundamental requirement that Lercel says isn’t easy to achieve. “You need completely defect-free mask blanks, and this involves a tremendous number of depositions of multilayer reflector material.”

For his part, Lercel believes that EUVL is on track but notes that double patterning is also attracting attention. A May 2006 SEMATECH survey listed the technique as a second choice for 32 nm manufacturing, with EUVL being the first. In the previous survey, done in 2004, the two-step process didn’t even make the list, in part because it was thought EUVL would be ready in time.


Double patterning is seen as a likely strategy in future semiconductor manufacturing because it allows the use of well-known optical lithography instead of new extreme ultraviolet lithography (EUVL). It requires taking a circuit pattern (on left), splitting it into two masks (middle) and then using both in succession to pattern a single layer in the final chip circuit. Image courtesy Kurt Ronse, IMEC.
Click here to enlarge image

With the deployment date approaching, and concerns growing, however, the two-step strategy is suddenly now being seriously considered. The final determinant may not be a technical issue. “The industry is now evaluating how feasible the economics are of introducing 193-nanometer double exposure,” says Lercel.

Applied Mechanical Corporation (Austin, TX), provider of outsourced technical, engineering and project management services to the semiconductor industry, has announced its acquisition of Phoenix-based Cleanroom Sciences (CRS). Applied Mechanical will now offer test, certification and maintenance services for cleanrooms and minienvironments.

Applied Mechanical expects the acquisition to strengthen its position as a leading outsource provider of on-site engineering, management, technical, and logistical support for advanced technology manufacturing.

According to Johannes Brinkmann, CFO of Applied Mechanical, “The acquisition is part of our strategy to achieve consistently strong, stable growth by delivering the scope and quality of services that our customers expect.”

Fabrinet, provider of manufacturing services for complex optical components, recently announced that its third and latest factory, completed in Nov 2005, is near capacity. The company plans to build a fourth factory in its Pinehurst campus manufacturing complex near Bangkok, Thailand. A ground-breaking ceremony was held last month.


With its latest facility near capacity, Fabrinet plans to build a fourth factory in its Pinehurst campus manufacturing complex near Bangkok, Thailand. Photo courtesy of Fabrinet.
Click here to enlarge image

The company expects its new 300,000-square-foot facility to accommodate the fast-growing demand for its optical components, module manufacturing and system assembly services. Anticipated growth in capital equipment, automotive and medical markets is also a factor. The facility is scheduled for completion in late 2007.

The new factory’s numerous assembly lines can be customized to support Class 100,000 to Class 100 cleanrooms for high-precision optoelectronic manufacturing, and sophisticated “dry rooms” to meet the ultralow-humidity requirements of medical devices. Additionally, the factory will accommodate Fabrinet’s unique, customer-specific “factory within a factory” operations, ensuring complete IP security and exact adherence to each customer’s desired manufacturing processes.

According to Tom Mitchell, chairman and CEO of Fabrinet, “The new building reflects the continued investment we’re making in Thailand, which we believe continues to offer a compelling manufacturing value proposition for complex high-mix, low- to medium-volume products.”

Last month I spoke about the relative role of tool manufacturers in the quest for efficient contamination control in the manufacture of ever more sensitive microelectronics. This is indeed an important question but only one among many constantly faced by the entire universe of contamination control user industries. How to achieve efficient contamination control and, specifically, across how large an environment, has been an age old question for everyone with a contamination control requirement. And, of course, the answer has been widely different depending on the specific application. Equally important to note, however, is that it has also been widely different depending on when the question is raised and the current state of the technology and market of the user industry.

Certainly, we’ve seen this in the semiconductor industry, where companies and facilities have shifted emphasis back and forth between minienvironments, large ballroom cleanrooms and hybrid approaches, depending on the level of technology of the product being manufactured and the cost/performance pressures of the marketplace. Likewise, major changes are in the works for the bio/pharmaceutical industry, which is increasingly faced with downward pricing pressures at the same time that it must ramp up production scales for increasingly contamination-sensitive products, particularly biologics.

And, for the bio/pharmaceutical industry, this challenge now expands outward to new users, such as compounding pharmacies, which must balance critical space limitations with exponentially growing demand for aseptically-handled products and stricter contamination control requirements. Some of the terminology is different (safety cabinets, gloveboxes, barrier/isolators, RABS), but the question is the same.

In the food industry, the complexities of implementing very large-scale aseptic processing operations and retrofitting improved contamination control approaches into existing conventional manufacturing lines (and manufacturing mindsets) are just beginning to be openly addressed.

Finally, looking ahead into the not-too-distant future, nanotechnology-scale products will upset the entire universe of existing contamination control solutions-raising all new challenges not only in product protection but in personnel and environmental safety as well.

The point is that the answer to the question of “how-and-how-large” has always been, and always will be-it depends on the time and place. For that reason, we’ll keep calling it the cleanroom question.

John Haystead,
Editor-in-Chief

Particles


February 1, 2007

Compiled by Angela Godwin

Partnership to develop food-safety compliance system
Smart Online Inc., provider of Software-as-a-Service (“SaaS”) for the small-business market, will partner with FoodLogiQ, LLC, designer of workflow, compliance and traceability systems, to develop branded food-safety compliance systems for industry associations. Under the partnership, Smart Online’s business application suite will incorporate FoodLogiQ food-industry traceability and compliance functionality. The new application is expected to help farmers, food manufacturers, grocers and restaurants meet their business and compliance needs at the same time. It will be customized to provide anonymous, aggregate data to industry associations to confirm their memberships’ level of compliance. Through the application, audit results from the associations’ members can be scheduled and recorded to help assure compliance to label claims of quality and safety.

Lithography light source manufacturer opens new facility

Gigaphoton Inc., a lithography light source manufacturer for the global semiconductor industry, announced that it has completed construction of a new building at its headquarters campus in Oyama, Japan. The new facility will house a state-of-the-art, Class 1,000 cleanroom that features expanded research and development capabilities and laser light source maintenance training for field service engineers. The new facility will also house Gigaphoton’s customer support administrative functions, as well as a spare parts warehouse.

According to Dr. Yuji Watanabe, president and representative director of Gigaphoton, the company’s decision to expand its existing facilities was based on the increased demand for its advanced light sources. “Gigaphoton’s high-quality, extremely reliable, and high-uptime products enable chipmakers’ fabs to run at benchmark levels. As a result, customers continue to turn to us as they realize the benefits afforded by our advanced lithography light source solutions, for which we provide superior service and support,” said Watanabe.

Dates announced for STAR Center training

Baxa Corporation has published the 2007 dates for training at its STAR (Skills Training, Academics and Resources) Center, a facility designed for cleanroom and pharmacy practice demonstration. The center (www.baxa.com/starcenter) is located at the company’s world headquarters south of Denver, Colorado. Baxa Corporation built the facility to provide professional education on pharmacy practice, cleanroom principles and compliance to regulatory requirements.

The STAR Center’s initial course offering, “Compliance Tools and Aseptic Certification for USP <797>,” debuted in September 2006, with sessions repeated in October and November. The USP 797 course will also be held: March 20-22; May 22-24; July 24-26; September 18-20; and October 23-25.

The ACPE-certified training targets pharmacy and IV managers, as well as personnel who compound sterile products or who are implementing cleanroom principles and practices that comply with USP <797> and industry best practice. Topics include cleanroom physical design and layout, engineering controls and airflow science, media fill testing, and principles associated with workflow, staff training, cleaning, monitoring, validation and documentation.

The rapidly building need for standards is driving increased committee activity and frequency of meetings

By David S. Ensor, PhD, IEST Fellow and director of IEST SPC 7: Nanotechnologies

In 2005, Technical Committee (TC) 229, Nanotechnologies (ISO/TC 229), was established by the International Organization for Standardization (ISO) with the British Standards Institute (BSI) serving as the secretariat and Dr. Peter Hatto of the United Kingdom as the chairman. The formation of this ISO technical committee was in response to the extraordinary worldwide growth of the nanotechnology field.

In 2004, the expenditures for nanotechnology research and development were estimated to exceed $4 billion USD. Forecasts indicate that, in the foreseeable future, nanotechnology will experience significantly accelerating worldwide activity. It is clear that international standards tailored specifically to nanotechnology are needed to support commerce.

The United States, represented by the American National Standards Institute (ANSI), joined ISO/TC 229 as a charter participating country. The Institute of Environmental Sciences and Technology (IEST) joined the ANSI-sanctioned U.S. Technical Advisory Group (TAG) to ISO/TC 229 as a charter member to represent the fields of contamination control and environmental testing. The role of the U.S. TAG to ISO/TC 229 is to develop and represent the position of the United States in the ISO process. I have had the pleasure of serving as IEST’s representative since its inception.

Because of the rapidly building need for standards, the committee activity and frequency of meetings have been greater than most standards committees. ISO/TC 229 has been meeting biannually and national advisory groups have been meeting much more frequently. The U.S. TAG has been meeting bimonthly.

ISO/TC 229 currently has 28 “Participating” countries and 8 “Observer” countries. The inaugural plenary meeting was held in London, England, in November 2005. The United States delegation at this and the following plenary meetings was led by Dr. Clayton Teague, director to the National Nanotechnology Coordination Office and chairman of the United States TAG. At the London meeting, the scope of ISO/TC 229 was established as follows:

Standardization in the field on nanotechnologies that includes either or both of the following:

  1. Understanding and control of matter and processes at the nanoscale, typically but not exclusively below 100 nanometers in one or more dimensions where the onset of size-dependent phenomena usually enables novel applications.
  2. Utilizing the properties of nanoscale materials that differ from the properties of individual atoms, molecules and bulk matter, to create improved materials, devices and systems that exploit these new properties. Specific tasks include developing standards for: terminology and nomenclature; metrology and instrumentation, including specifications for reference materials; test methodologies; modeling and simulation; and science-based health, safety and environmental practices.

At the meeting in London, the following working groups were established:

  • Working Group 1-Terminology and Nomenclature, with the convenorship held by Canada.
  • Working Group 2-Measurement and Characterization, with the convenorship held by Japan.
  • Working Group 3-Health, Safety and Environment, with the convenorship held by the United States.

One principle established at the first meeting was that the interdisciplinary nature of nanotechnology will require liaison and coordination with a large number of other ISO technical committees and other international standards bodies. For example, I was elected to represent ISO/TC 229 as liaison to ISO/TC 209, Cleanrooms and Associated Controlled Environments.

As the nanotechnology industry matures, facility requirements will need to be defined for the development and production of the wide range of potential products containing nanomaterials. It should be noted that at the national level, IEST, in anticipation of the need for information on designing, constructing and operating nanotechnology facilities, organized in 2005 a new working group, IEST-WG-CC210: Forum for Nanoscale Research Facilities. This IEST working group is lead by Ahmad Soueid of HDR Architecture, Inc. and Hal Amick of Colin Gordon and Associates.

The second plenary meeting of ISO/TC 229 was held in Tokyo, Japan, in June 2006. The emphasis of the Tokyo meeting was on organizing the work of the committee. For example, because the effort in TC 229 is expected to become quite large, a Chairman’s Advisory Group (CAG) was organized to work on policy issues. The CAG consists of the chairman, working group convenors, and other national members elected by region.

At the working group level, the priority in Japan was to develop “road maps,” structures or strategies so that appropriate standards are developed on a timely basis. Development of a structure is particularly important in the area of ISO/TC 229 Working Group 1-Terminology and Nomenclature. Because of the wide range of disciplines involved in nanotechnology, vocabularies are currently being developed in a haphazard manner. This may lead to imprecision and confusion as the field matures, thereby adversely affecting commerce and safety considerations. The principle activity within the TC at this point is the definition and writing of work item proposals for the development of documents. These work item proposals are championed by various national organizations and submitted to the TC for a formal vote by the participating member countries for approval by ISO. Upon approval, these proposals become work items within specific working groups. The first approved work item within ISO/TC 229 was ISO/AWI TS 27687 Nanoparticle-Terminology and Definitions, submitted and lead by the United Kingdom in Working Group 1. This document will be derived from BSI Publicly Available Specification (PAS) 71:2005 Vocabulary-Nanoparticles.

The third plenary meeting of ISO/TC 229 was held in Seoul, Korea, in December 2006. The primary purpose of the meeting was to refine working group strategic plans. A survey conducted during the last six months was used to support working-group planning sessions. Work was continued on the second approved work item, Health and Safety Practices in Occupational Settings Relative to Nanotechnologies, lead by the United States in Working Group 3.

The national bodies of Japan, Korea and the United States within Working Group 2 were encouraged to submit work item proposals on the measurement of carbon nanotubes. Further development of liaisons with other organizations was an important item of business. For example, plans for coordination by ISO/TC 229 with the newly organized International Electromechanical Commission (IEC), a standards committee on nanotechnology related to electrical and electronic products and systems, are currently being developed.

The next planned plenary meetings of ISO/TC 229 will be held in Berlin, Germany, in June 2007 and in Singapore, Malaysia, in December 2007.

Click here to enlarge image

David S. Ensor is the director of the Center for Aerosol Technology and an RTI senior fellow. Dr. Ensor received his PhD in engineering from the University of Washington. He has conducted contamination control, aerosol and indoor air quality research for over 30 years, and is a founding editor of Aerosol Science and Technology. Dr. Ensor has served as President of the American Association for Aerosol Research and the International Aerosol Research Assembly, and he is the convenor of ISO/TC 209 WG 7. Dr. Ensor is a Fellow of the IEST and of the American Society of Heating Refrigerating and Air-Conditioning Engineers.

About IEST

IEST is an international technical society of engineers, scientists, and educators that serves its members and the industries they represent (simulating, testing, controlling, and teaching the environments of earth and space) through education and the development of recommended practices and standards. IEST is the Secretariat for ISO Technical Committee 209, Cleanrooms and associated controlled environments, charged with writing a family of international cleanroom standards. IEST is also an ANSI-accredited standards-development organization. For more information, contact IEST at [email protected] or visit the IEST Web site at www.iest.org.

Additional resources

  1. http://www.ansi.org/news_publications/news_story.aspx?menuid=7&articleid=1389
  2. http://www.bsi-global.com/Manufacturing/Nano/index.xalter
  3. http://www.iest.org
  4. http://www.iso.org/iso/en/commcentre/pressreleases/archives/2005/Ref980.html
  5. http://www.iso.org/iso/en/commcentre/pressreleases/archives/2005/Ref978.html
  6. http://www.nano.gov/NNI_07Budget.pdf

ESTECH, the IEST’s 53rd annual technical meeting and exposition, will take place April 29-May 2 at the Indian Lakes Resort in Bloomingdale, Illinois. With seminars and tutorials focused on contamination issues, the event offers contamination control professionals a unique opportunity to learn from and network with their peers and colleagues in the industry.

New this year, a special seminar topic for contamination control professionals is avail-able. “Compounding Sterile Pharmaceuticals,” presented by members of the USP <797> committee and CleanRooms magazine, will focus on U.S. Pharmacopeia (USP) Chapter 797, Pharmaceutical Compounding: Sterile Preparations.

The American Society of Health Systems Pharmacists (ASHP) recommends that all “persons who compound sterile preparations should exercise their professional judgment to obtain the education and training necessary to prove their competence in managing sterile compounding facilities and in sterile compounding processes and quality assurance.” USP <797> is the first set of relevant standards to address this requirement.

Published in 2004, USP <797> is currently under revision. Proposed changes to the 2004 standards were released in May 2006 to address inadequacies and clarify ambiguities in the document and, as a result, new concerns and questions have arisen.

“CleanRooms is very pleased to sponsor this special session at this year’s ESTECH,” said John Haystead, chief editor of CleanRooms magazine. “Hospital pharmacies, and specifically the compounding of sterile pharmaceuticals (CSPs), are among the most dynamic and expanding segments of the contamination control industry right now. Our live Webcasts on the topic have had unprecedented audience sizes and participation, and I’m certain this program’s topics and distinguished speakers will draw major interest as well.”

Presenting the seminar are members of the USP <797> committee, including Jim Wagner, president of Controlled Environment Consulting, and Eric Kastango, president and CEO of Clinical IQ. Also presenting: Kenneth Mead, research mechanical engineer for NIOSH, and R. Vijayakumar, consultant to the contamination control industry.

The upcoming seminar and panel discussion will provide a forum in which to explore the latest information on the status and implementation of USP <797>.

For more information on the seminars and tutorials ESTECH will offer, or to register for the event, visit the IEST Web site at www.iest.org.

World market for AMC control


February 1, 2007

Importance of controlling airborne molecular contamination impacts filter manufacturers and media suppliers

By Robert McIlvaine and Karen Vacura, The McIlvaine Company

Airborne molecular contamination (AMC) is non-particulate chemical contamination in the form of vapors or aerosols that has a detrimental effect on a product or process. The need for AMC control in cleanrooms continues to grow as technology advances.

A necessity in the lithography process, AMC control is becoming more important in other cleanroom processes. As processing moves to faster speeds, manufacturers are seeing increasing sensitivity to contaminants, affecting yields.

Some common reasons for instituting AMC control are to prevent corrosion during processing and to protect reticles during transport or storage, according to Christopher Muller, technical director for Purafil, Inc., a leader in the engineering and manufacture of gas-phase air filtration media, systems and monitors. In leading-edge fabs, a large amount of outside air is pulled in for ventilation and pressurization purposes, and an even greater amount of air is recirculated, all of which needs to be monitored for molecular contamination. Additionally, reticles are at risk of damage due to haze formation from molecular contamination.

The International Organization for Standardization (ISO) has recently published ISO 14644-8, Cleanrooms and associated controlled environments–Part 8: Classification of airborne molecular contamination. This part of ISO 14644 covers the classification of airborne molecular contamination in terms of airborne concentrations of specific chemical substances (individual, group or category) and provides a protocol for test methods, analysis and time-weighted factors within the specification for classification. The document is designed for use in a wide range of industries, including microelectronics, pharmaceuticals and medical devices.

Applications for AMC control

AMC sources fall into two categories: internal and external. Some internal sources could be chemicals used in the manufacturing process, accidental spills, and off-gassing of cleanroom components. External sources vary by plant location and include factory emissions and auto exhaust. For example, in Taiwan, one fab’s exhaust can be the next fab’s intake. Proximity to farm fields can also raise the need for AMC control. In general, outside pollutants are removed from the make-up air, and indoor-generated contaminants are removed from the recirculating air.

AMC control is needed at different points in a facility, including: make-up air; re-circulated air in the ballroom, minienvironments and enclosed areas; fan filter units for localized control; and exhaust air. With the decrease in wafer carrier sizes, certain processes may only require AMC control in a smaller enclosed area, rather than for the whole ballroom. In a 200,000-square-foot semiconductor cleanroom, about 30 to 40 percent of the area is devoted to lithography processes. Only this area, roughly 60,000 to 80,000 square feet, needs AMC control.

According to Michael O’Halloran, director of technology at CH2MHill, engineering firms look at specifics for each application to find the most efficient and economical solution, balancing near-term and future costs. For example, engineers try to determine whether a contamination event is temporary, perhaps due to outgassing of new construction, or whether it’s a potential long-term problem.

CH2MHill uses a virtual airflow-modeling program, Computational Fluid Dynamics (CFD), to monitor contamination during process operations. This tool allows for the characterization of overall cleanroom airflow patterns, pressurization and temperature effects during the design phase of the cleanroom. The general approach is to improve the overall airflow patterns by minimizing recirculation zones that collect and transport contaminants, and to select areas for AMC control. CFD can also be used to track down the source of contamination in an existing cleanroom.

O’Halloran explains that the incorporation of a minienvironment into the lithography tool is part of a standard setup. Some tools require the background air to be controlled to a certain level in the cleanroom, and others rely on the minienvironment of the tool to do it. The life of the tool’s AMC filter is determined by the extent of challenges it receives: If the cleanroom AMC is controlled, the minienvironment filter will have a longer life.

Solutions and products

When choosing a system for AMC control, the most important consideration is what types of gases affect the process and personnel, and at what level. In general, AMC is specified to be less than 1 part per billion (ppb) over the service life of the system.

AMC control requires a combination of media and filter types, including prefilter usage, according to Purafil’s Muller. Types of common AMC filtration systems are:

  • Adsorption/Chemisorption: Adsorption uses granular activated carbon and/or activated aluminas. The removal capacity is directly related to total surface area. Chemisorbent systems use adsorption and specific chemicals added to activated carbons and/or aluminas.
    A reaction occurs with contaminants to form stable chemical compounds that either bind to the media or are harmlessly released into air.
  • Bonded media panels use granular adsorbents, such as activated carbon, bonded and formed into monolithic (single-piece) panels.
  • Ion exchange systems use synthetic polymers with positive or negative charged sites on pleated membrane or spongelike, flat sheets. This type of contamination control is mainly used in liquid applications but is finding specific niches as AMC control, such as for ammonia.

Practically all chemical filtration media today are manufactured from activated carbons and/or alumina. Specific chemical additives are utilized to impart special characteristics to the media. The target contaminant determines what chemicals are impregnated on the carbon or alumina. Potassium permanganate is a common, broad-spectrum chemical used almost exclusively on activated alumina since it cannot be effectively used with activated carbon. Pore size and structure of activated carbon can also affect how impurities are adsorbed.

Blended media for multiple contaminants are also used. For instance, alumina impregnated with potassium permanganate used in conjunction with plain or impregnated granular activated carbon provides a very broad-spectrum, gas-phase air filtration system. However, many manufacturers prefer to focus their AMC control on the specific contaminant type. Also, blended media have a shorter service life due to the reduction in the quantity of each media as compared to a system employing both media in individual stages. Filter life is based on capacity, with variables of temperature, airflow velocity, and contaminant.

Chris Hicks, a sales representative for Calgon Carbon Corp., explains that activated carbon works for most applications. Calgon manufactures several hundred carbon products to address almost any contaminant, and also offers activated alumina products. Hicks points out that AMC control needs to change as new exhaust regulations are passed. There is currently a shift toward adsorption from combustion. Calgon Carbon is starting to look at workstation filtration, targeting exhaust at site generation of contaminants. In this application, a separate module not integral to lab hoods would be employed.

Major suppliers of AMC filters are M&W Zander, Camfil Farr, and Purafil. American Air Filter (AAF) has developed a line of chemical filters as well. Asian companies Takuma, Takasago Singapore, and Taiwan Nitta also supply chemical filters, primarily aimed at minienvironments.

Cost considerations

Purafil’s Muller explains that costs can differ widely with application needs and whether the system is customized or integrated into an existing system. Chemical filter costs can range from $40 to $50 for a 24-inch x 24-inch x 2-inch outside

filter to $3,000 for a 24-inch x 24-inch x 12-inch tool filter. Chemical filters can have a higher pressure drop than HEPA filters, so increased energy costs should also be considered.

Monitoring filter life is another cost issue. According to Lighthouse Worldwide Solutions, depending on what chemicals are being monitored and how many locations are sampled, the cost can range from $3,000 for a single sensor to $400,000 for an entire system that samples multiple locations.

Performance and service life of filter systems differ with contaminant gas. CH2MHill’s O’Halloran says that monitoring must be a continuous process since failure load of chemical filters can be very sudden, over a span of just days or weeks. One efficient monitoring technique is to take a sample of the filter and test it; another method, although with less ability to predict future failure, is to monitor filter discharge.

AMC market forecast

Revenues for AMC removal have been projected based on the expected penetration in the microelectronics industry. A high penetration of the semiconductor industry and lower penetration of other microelectronics applications has been assumed. Other factors include filter life and cost.

Definition of the product is difficult. The filter element itself could be a stand-alone product or part of the total filter system. In either case, there is some additional ductwork, fan and housing cost for the extra treatment step. Forecasts for both filters and systems have been calculated.

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AMC filter sales are projected to rise from $50 million in 2006 to $67 million in 2010, with the bulk of the sales to the semiconductor industry (see Fig. 1).

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AMC system sales are projected to rise from $100 million to $136 million during the same period (see Fig. 2).

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By 2010, China will account for 7 percent of the sales but will also be increasing purchases at double-digit annual rates. Asian countries will account for the majority of AMC filter purchases (see Fig. 3).

Robert McIlvaine is president and founder of The McIlvaine Company in Northfield, IL. The company first published Cleanrooms: World Markets in 1984 and has since continued to publish market and technical information for the cleanroom industry. He can be reached at [email protected].

Karen Vacura is the air filtration market editor for The McIlvaine Company. She can be reached at [email protected].

References:

  1. Polen, Morgan, Peter Maquire. “AMC Measurement and Control,” Lighthouse Worldwide Solutions, application note, http://www.golighthouse.com.