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ISMI has been the leader in implementing small-lot manufacturing and single wafer processing for 300mm Prime and next-generation factory (NGF) 450mm manufacturing. By driving and gathering the implementation requirements from chip makers and equipment suppliers, ISMI makes it simpler for chip makers to select NGF MES supplier products and plan for their fab MES deployment. For the advanced 300mm Prime and the NGF 450mm, the main goal is to enhance the productivity improvements necessary to implement fully continuous processing. To achieve this goal, wafer processing interruptions and improving waste reduction in the fab are the keys to success.

Brandon Lee, Dennis Talbert, CIMAC, San Jose, CA USA

As global competition increases, semiconductor chip makers are constantly looking for ways to be more efficient and competitive. At a time when getting more for less has become a common buzzword in any business sector, it is an absolute requirement for everyone to re-evaluate what they have and initiate changes to lower costs and maximize profits. In the semiconductor industry in particular, there exists a continuous effort to raise manufacturing efficiency to a higher level.

Given the current economic environment, one may think it risky to start a new project — on the contrary, it is an ideal time to focus on productivity improvements and cycle time reduction. When the upturn hits, those who seek to get more for less will benefit most from investing in manufacturing efficiency.


MES deployment lifecycle.
Click here to enlarge image

For NGF projects, there are priority items from the 19 Point Guidelines published by ISMI. Many of them, including equipment availability and predictability, are related to improvements for equipment suppliers. This drives the factory manufacturing execution system (MES) to be smarter than the MES that are running in current 300mm fabs. The NGF MES must be able to adapt to predictive and preventive maintenance, wafer delay reduction, continuous processing of materials, and most importantly, provide a single point of control for the factory system.

MES: replacement or upgrade

Manufacturing execution systems are ofTen a leading factor in achieving the efficiencies required for 450mm manufacturing by coordinating the flow of materials, facilitating communication between tools, relaying vital information to operational management, etc. The application of new versions of sofTware (either the MES sofTware itself or supporting sofTware) is ofTen central to achieving these efficiencies and a competitive advantage. In addition, with new manufacturing technologies and increasing business and customer reporting demands, more functionality is required. All of these are reasons that may require upgrade or replacement of existing MES sofTware solutions.

However, the very thought of changing an operational MES can place significant stress on the operational organization of a fab. Do the lean fabs of today have the workforce to evaluate and implement possible alternatives? This article discusses many of the significant considerations involved with the evaluation of MES alternatives and upgrades; the strategies for requirements gathering, management, and tracking; the implementation of MES functionality; and, finally, the deployment of an operationally significant solution.

The decision process

There can be many driving forces to replace an existing MES. Several are discussed below.

Technology obsolescence. The end of life of a previously supported and successful technology can be a necessary driving force for change. An example of this would be the need to migrate the MES from one server platform to a current platform technology.

New technologies. The desire to take advantage of newer technologies is another motivator. Advancements in human/machine interfaces (HMI) have sparked the move to a change in operational sofTware as users sought to make operational personnel more productive and data inputs more accurate. Over the years, we have seen MES sofTware transform from character-based terminal interfaces to Windows-based GUIs to web-enabled operator and engineer user interfaces.

Business consolidation. The business/technical environment response to marketplace conditions has also brought about the need to change an MES at an operational organization. If companies merge, it is probably better in the long run to standardize on a single MES solution. As a result, at least one of the organizations will likely have to change its operational MES.

Tool connectivity. Another driving force for the change of MES sofTware solutions is tool connectivity. As more sophisticated tools and processing technologies are adopted, there is a need to introduce more automation to perform transactions previously done manually, and to reduce input processing errors by human operators. In the drive to reduce recurrent costs and make fabs less labor intensive, the capabilities of new or upgraded MES sofTware are essential for the cost-conscious fab operations of today. This frequently requires MES sofTware upgrades or even migration to a new MES.

The latest versions of MES sofTware have added security capabilities to allow users to access data that is required for them to conduct their tasks but at the same time restricting them to only the data that they have a need to know. This becomes essential in protecting an end user’s intellectual property (IP) and is a requirement for fabs acting as foundries. However, even when the MES is limited to only one end user, access to data can be limited by the role that user performs.

In addition, the introduction or change of manufacturing technology in the fab itself can be a motivation to change MES technology to the most current products. Many of the popular legacy MES products lack the capabilities to support a fab migrating to new product manufacturing sizes; such as the movement from 200 to 300mm technologies, for example.

In CIMAC’s latest two projects to upgrade MES, the major motivators to accomplish the transition were changes of manufacturing technology; the desire to take advantage of technological advancements; tool connectivity for new tools to support advances in manufacturing technology; and taking advantage of additional security features to protect customer’s intellectual property. It is anticipated that these conditions, as well as possible business consolidations sparked by the world’s current dynamic business climate, will continue to be the motivators for future MES upgrades and migrations.

Handling MES upgrades

We have identified the following factors as key to determining whether to manage and implement the changed MES sofTware environment with external assistance, or to manage and implement with internal resources: management of business requirements; availability of internal work force; internal work force’s expertise in MES nomenclature and capabilities; and the company culture of the operational fab. Clearly, it need not be a case of all internal resources or all external. However, the following discussion may provide some insights into what the considerations might be in order to evaluate whether to utilize external or internal resources.

Establish whether internal resources are knowledgeable and experienced with the scope of activities required to bring the fab’s business requirements into a viable, operational MES. This amounts to much more than operational domain or product processing knowledge. It includes critical tasks such as business analysis, requirements collection and management, rendering functional specifications in a way that sofTware can be produced to satisfy them, change management affecting the data, the sofTware development, the operational environment and other relevant processes and artifacts, as well as an understanding of sofTware validation and verification practices.

Fab management must be prepared to assign significant resources to a new MES implementation. Given that an operational fab is still going to require substantial engineering and legacy MES support, will the necessary internal work force be available? Ken Simpson, a long-time MES consultant, indicates that as much as 10% of engineering staff may be involved in the project [1]. In addition, will the fab engineering staff have the necessary expertise in MES nomenclature and capabilities? This is not typically a fab engineer’s core expertise.

CIMAC, for example, recently provided an end user service program that enabled a semiconductor manufacturer to assess the gap between its existing capabilities and what was desired, and evaluate different vendor proposals as solutions to alleviate problem areas. Senior CIMAC MES specialists analyzed the end user’s current manufacturing workflows and manufacturing applications to provide a complete picture of current manufacturing operations. Working in conjunction with internal management, they identified improvement opportunities, analyzed potential technology investments, and provided a recommendation as to the best proposed vendor alternative.

The company culture of the fab is also a determining factor in making the decision. Issues of concern are whether internal documentation is adequate to describe processes and procedures, or whether such processing is performed by rote, or by some collective memory of the operational culture. A lack of clear documentation of operational processes may hinder any vendor from translating perceived functional requirements into an implementation that reflects what fab operations really wants done. Are there areas of special concern that need attention and, if so, does internal staff have the expertise and the time to address these special concerns?

CIMAC’s latest experiences revealed several cases of de facto procedures that superseded all existing documentation of what was done by whom, how, and when. Requirements gathering personnel had to insist upon meeting with operational-level stake holders to clarify perceived operations from the real and the desired. In addition, the management of requirements changes brought about by changes in technology, personnel, or critical reviews of the documented requirements had to be managed and communicated to implementation personnel. These tasks were critical to the success of the implementation migration.

Defining requirements of an MES System

As shown in the figure, selecting a best of breed MES entails requirements collection, analysis, and management — very important to a successful implementation and deployment of a MES whether it be a mere upgrade or a completely new system. When evaluating different solutions it is important to ensure that the request for quotation (RFQ) matches what the operational fab requires. Several methodologies and techniques can be used to do this. However, there will be a need to define the important business processes. In many older fabs, documentation of these processes may be nonexistent or out of date. To avoid costly sofTware revisions in the future, business models and processes need to be rigorously defined and documented.

One must be able to trace these essential business requirements throughout the implementation and deployment process of the MES. To accomplish this, a change management process must be specified for requirements. In fact, not only might the requirements be changed during the selection, implementation, and deployment of the MES, but relevant processes, products, data, personnel, etc., will be changing as well. Successful deployment will depend to a great extent on how the changing environment is managed during this time. Will internal processes and resources have the expertise and bandwidth to accomplish these tasks while maintaining operational throughput?

Another concern is how to put the RFQ into MES language so that requirements are fulfilled as desired. In other words, the business logic and processes need to be translated into “MES speak” to better communicate with the MES sofTware vendors. The RFQ needs sufficient definition to cover details that could otherwise be overlooked. For example, requirements for specifying a state model to reflect processing capability of a tool should also require that the model be configurable with additional states the end user’s business practices may require at some later time. The requirements specification activity may be an area where there is a need for a company with core expertise in MES integration to take part.

Reducing risk during vendor selection

MES sofTware vendor selection can be a highly resource-consuming endeavor. How can fab operations management ensure that it gets the most out of this effort regardless of whether internal or external resources are used? Our experience has been that the following actions provide some valuable input to the MES vendor selection process and substantially enhance the probability of a successful implementation and deployment.

Product demonstration. A demonstration that shows the ability to solve problems that would realistically be encountered is key, along with reference site visits. These sites should use a configured system similar to the one being considered. Additionally, get the vendor product in front of staff that will use it, both operations as well as engineering personnel. This will provide valuable feedback on usability features as well as provide helpful initial insights into how the MES standard product is a match for your fab operations.

We specifically recommended a visit to the vendor’s demonstration lab for operational personnel to view the HMI that would assist with the movement of lots, the collection and analysis of data, and the changing of equipment status. An alternative to this would be the set-up of a functional demonstration in the customer’s environment to garner feedback and validate the operational functionality of the potential solution.

Staff a quality assurance function. A quality assurance staff that does more than merely functionally test the delivered sofTware is important. A successful deployment is dependent upon reviews of the development process from planning through the installation. On recent projects, we have recommended that operational personnel participate in functionally testing sofTware early in the development process, which enables significant feedback on the effectiveness of the HMIs, as well as providing validation of the completeness of the delivered functionality.

We also recommend an organization plan for a realistic performance simulation or characterization before the final deployment. It is important to know well beforehand how the manufacturing sofTware is likely to behave when your organization starts running a full load of product. A well-thought-out and developed performance characterization will protect your organization from future surprises and enable your organization to solve bottlenecks before they actually occur [2].

Staff a change management function. A change management function will be even more important if you are migrating from one MES to another. The production environment is dynamic, with products and manufacturing processes constantly changing and being refined. Business requirements are likewise dynamic and reporting requirements and customer requests continually need to be updated, which will have an impact on the MES sofTware and the system requirements. These changes need to be managed and controlled. It is likely that the fab’s existing infrastructure and processes will not be able to account for all of this new change in the environment. Consequently, a change management function focused on the MES implementation needs to be staffed and set to work from the requirements collection phase through data migration and final system deployment.

Successful deployment execution

First, and most importantly, one must have the highest level of management commitment. The support from the top levels of management is crucial to the success of the plan. At some point in time, whether ample use of internal or external resources is utilized, scarce resources will be requested and the backing of top management will be required.

Secondly, there is a definite need for strong, experienced project management — from the vendor and the end user sides. On one recent upgrade deployment, the vendor had three different project managers during the duration of a one-year project. This change in leadership led to some issues with the interpretation of requirements, as well as some issues in execution to schedule. Indeed, there were not only changes in project management by the vendor but also by the end user. This lack of continuity in management led to communication issues with regard to schedule and the interpretation of requirement commitments. All of these issues were resolved once stable project management was implemented.

Comprehensive schedules with details of all resources needed from the end user are essential to making a successful deployment possible. Our recent experience has indicated that it is necessary but not sufficient for the vendor to present and track a plan only specifying vendor-supplied resources without indicating the essential end-user-supplied resources. For example, an early validation of the HMI is not possible without having the operational personnel interacting with it.

MES upgrades or replacement projects need a risk management structure to identify risk and must have a mitigation plan ready. The risks and mitigation plans must be updated constantly to keep pace with the progress of the sofTware development as well as the constantly changing business and manufacturing process environment.

We recommend that sufficient resources from both the end user and the vendor be definitely committed before the project starts. This includes a clearly defined budget. Once again, periodic schedule and plan reviews will highlight the resource issue and management commitment and the risk and mitigation plans will assist in reacting to resource issues.

Finally, since we have stressed the dynamic environment in which these upgrades and migrations will be taking place, our experience has shown that the need for a change management process that is documented, staffed, and enforced is of tremendous value in ensuring the successful deployment of such a project. We recommend that a specific project resource for this task be assigned if it cannot be integrated into the end user’s existing organizational infrastructure.

Conclusion

Ultimately, it is not an easy task to improve equipment productivity, lower cycle time, and transition into small lot size and single wafer manufacturing. It requires significant factory operation improvements to extract the full benefit from these measures and that is why requirement gathering and careful planning of MES selection is one of the top priorities in the NGF productivity improvement lifecycle.

References

  1. Private discussion.
  2. B. Lee, S. Dash, “Performance Testing Manufacturing Execution Systems (MES),” Semiconductor Fabtech, 2008.

Brandon Lee received his two BS degrees, mathematics and computer and information science, from the U. of Oregon and wrote a post-undergraduate honor’s thesis in fractals and now is the director of marketing and business development at CIMAC, Inc., 1590 The Alameda, suite #100, San Jose, CA 95126 USA; ph.: 409-985-4300; email [email protected].

Dennis Talbert received his BA from Howard U. and is an MES and sofTware quality consultant.

March 27, 2009: The head of SPIE, the International Optics and Photonics Society, urged a panel in Washington, D.C., to push Congress for a more-comprehensive national policy on development of photonics research, according to a report in Photonics Online.

Eugene Arthurs told a three-person panel before the US-China Economic and Security Review Commission that the current photonics technology portfolio in the United States is “fragmented.” He said that a national policy would apply Department of Energy research, for example, into solar energy manufacturing, according to the report.

The commission reports to Congress on the trade and economic relationship between the United States and China.

“The US may continue to be world leaders in the science of LEDs or the semiconductor lasers that power the Internet, but the location of the semiconductor foundries and the know-how to manufacture in volume suggest that these ‘green manufacturing’ jobs will be outside the US,” Arthurs said.

March 19, 2009: NanoVentures Australia has registered a new company, Quintain NanoSystems, to develop nanoparticle-based imaging and diagnostic tools.

Quintain has a portfolio of contrast agent technologies developed with the University of Melbourne, the Baker Heart Research Institute, and RMIT University. Led by Jeanette Pritchard, the Qunitain team has had discussions with potential development partners and investors, and will be presenting to potential stakeholders through April and May of 2009, according to a NanoVentures news release.

Quintain NanoSystems (Quintain NS) is the vehicle established in 2007 from the bionanotechnology activities of Nanotechnology Victoria Ltd. Its focus is toward development and commercialization of diagnostic reagents and devices for human and animal health industries.

March 18, 2009: Researchers at Rensselaer Polytechnic Institute have developed a new technique for growing slimmer copper nanorods, a key step for advancing integrated 3-D chip technology.

These thinner copper nanorods fuse together, or anneal, at about 300°Cg temperature could make the nanorods ideal for use in heat-sensitive nanoelectronics, particularly for “gluing” together the stacked components of 3-D computer chips.

“When fabricating and assembling 3-D chips, and when bonding the silicon wafers together, you want as low a temperature as possible,” said Pei-I Wang, research associate at Rensselaer’s Center for Integrated Electronics. “Slimmer nanorods, by virtue of their smaller diameters, require less heat to anneal. These lower temperatures won’t damage or degrade the delicate semiconductors. The end result is a less expensive, more reliable device.”

Experimental 3-D computer chips are comprised of several layers of stacked components. Wang said these layers can be coated with thin nanorods, and then heated up to 300°C. Around that temperature, the thin nanorods anneal, turn into a continuous thin film, and fuse the layers together. This study was the first demonstration of slimmer nanorods enabling wafer bonding, according to Wang.

Fundamental research concerning the slimmer nanorods was led by Toh-Ming Lu, the R.P. Baker Distinguished Professor of Physics at Rensselaer. Results of the study were recently published in the journal Nanotechnology. Research into wafer bonding and incorporating the slimmer nanorods into 3-D integrated computer chips was led by James Jian-Qiang Lu, associate professor in the Department of Electrical, Computer, and Systems Engineering (ECSE) and the Center for Integrated Electronics (CIE) at Rensselaer. Results of the study were recently published in the journal Electrochemical and Solid-State Letters.


Scanning electron images, at the same magnification, of copper nanorods grown without interruption (top), with two interruptions (middle), and with six interruptions (bottom). (Photo courtesy of RPI)

The slimmer copper nanorods were formed by periodically interrupting the growth process. The vapor-deposition process was occasionally halted, and the fledgling nanorods were exposed to oxygen. This resulted in a forest of nanorods with diameters between 10-50nm — far smaller than the typical 100nm diameter copper nanorods grown conventionally without interruption.

Vast forests, or arrays, of copper nanorods are produced by vapor deposition at an oblique angle. In a conventional setting, with an uninterrupted stream of copper atoms deposited in a vacuum onto a substrate, the deposition angle naturally results in taller, thicker nanorods.

Periodically interrupting the deposition, and exposing the copper nanorods to ambient air, however, leads to oxygen being absorbed into the surface of the nanorods. During subsequent depositions, this oxidized copper helps to prevent the vaporized copper atoms from migrating away from the very tips of the nanorods. This ensures the nanorods grow taller, without necessarily growing in diameter. The more growth interruptions, the thinner the resulting nanorods, Wang said.

Wang and the research group have filed for a patent for this new technology. The patent is currently pending.

March 11, 2009: New research from Rice University and the University of Oulu in Oulu, Finland, finds that carbon nanotubes could significantly improve the performance of electrical commutators that are common in electric motors and generators.

The research, which Pulickel Ajayan, Rice’s Benjamin M. and Mary Greenwood Anderson Professor in Mechanical Engineering and Materials Science. “The technology is widely used in industry, both in consumer gadgets as well as larger electrical machinery, so this could be a very interesting, near-term application for nanotubes.” The combination of mechanical and electrical properties of nanotubes makes this possible.

The carbon nanotubes used in the study are hollow tubes of pure carbon that are about 30nm in diameter. By comparison, a human hair is about 100,000nm in diameter. In addition to being small, nanotubes are also extremely lightweight and durable, and they are excellent conductors of heat and electricity.

Because of these properties, the researchers decided to test nanotubes as brush contacts. Brush contacts are conducting pads held against a spinning metal disc or rod by spring-loaded arms. Current is passed from the spinning disc through the brush contacts to other parts of the device.

To test the feasibility of using carbon nanotube brush contacts, the research team replaced the ordinary copper-carbon composite brushes of an electric motor with small blocks that contain millions of carbon nanotubes. Under an electron microscope, these millimeter-square blocks look like a tightly packed forest.


Pads of nanotube “forests ” were tested as brush contacts. (Credit: P. Ajayan/Rice University)

From Ajayan’s previous work, the team knew that these nanotube forests react something like a “memory foam” pillow; they regain their shape very quickly after they are compressed.

“This elasticity is something that’s not found in existing composites that are used for brush contacts, and that’s the essence of why the nanotube brush contacts perform better: They keep much more of their surface area in contact with the spinning disc,” said Robert Vajtai, faculty fellow at Rice. Vajtai worked on the study with Ajayan and a group of researchers in Finland led by University of Oulu Researcher Krisztian Kordas.

The team believes that the improved contact between the surface of the spinning disc and the brush accounts for the 90% reduction in lost energy.

February 26, 2009: Evolutec Group plc has announced the proposed acquisition of Nanoco Tech plc, a nanotechnology company based in Manchester, UK. Once the acquisition is approved by shareholders, the enlarged group will be known as Nanoco Group plc and have a market capitalization of approximately $55.2 million.

The acquisition constitutes a reverse takeover, according to a company news release.

Nanoco is involved in the development and manufacture of fluorescent semiconducting materials called quantum dots.

Nanoco’s business strategy is to work in partnership with quantum dot application developers, the company said, adding that the developers tend to be large global technology companies working to incorporate quantum dots into a specific end use application such as LEDs, displays and solar cells.

February 23, 2009: Small is promising when it comes to illuminating tiny tumors or precisely delivering drugs, but many worry about the safety of nano-scale materials. Now a team of scientists has created miniscule flakes of silicon that glow brightly, last long enough to slowly release cancer drugs, then break down into harmless by-products.

“It is the first luminescent nanoparticle that was purposely designed to minimize toxic side effects,” said Michael Sailor, a chemistry professor at the University of California, San Diego who led the study.

Many nanoparticles tested in research labs are too poisonous for use in humans.

“This new design meets a growing need for non-toxic alternatives that have a chance to make it into the clinic to treat human patients,” Sailor said.

The particles inherently glow, a useful property that is most commonly achieved by including toxic organic chemicals or tiny structures called quantum dots, which can leave potentially harmful heavy metals in their wake.

When the researchers tested their safer nanoparticles in mice, they saw tumors glow for several hours, then dim as the particles broke down. Levels dropped noticeably in a week and were undetectable after four weeks, they report in Nature Materials February 22.

This is the first sudy to image tumors and organs using biodegradable silicon nanoparticles in live animals, the authors say.

The particles begin as thin wafers made porous with an electrical current then smashed to bits with ultrasound. Additional treatment alters the physical structure of the flakes to make them glow red when illuminated with ultraviolet light.


New silicon nanoparticles illuminate tissues without harm. (Credit: Luo Gu)

Luminescent particles can reveal tumors too tiny to detect by other means or allow a surgeon to be sure all of a cancerous growth has been removed.

These nanoparticles could also help deliver drugs safely, the researchers report. The cancer drug doxorubicin will stick to the pores and slowly escape as the silicon dissolves.

“The goal is to use the nanoparticles to chaperone the drug directly to the tumor, to release it into the tumor rather than other parts of the body,” Sailor said.

Targeted delivery would allow doctors to use smaller doses of the drug. At doses high enough to be effective, when delivered to the whole body, doxorubicin often has toxic side effects.

At about 100 nanometers, these particles are bigger than many designed to deliver drugs, which can be just a few nanometers across — a thousand times smaller than the diameter of a human hair.

Their larger size contributes to both their effectiveness and their safety. Large particles can hold more of a drug. Yet they self-destruct, and the remnants can be filtered away by the kidneys.

Close examination of vulnerable organs like liver, spleen and kidney, which help to remove toxins, revealed no lasting changes in mice treated with the new nanoparticles.

by Griff Resor, Resor Associates, SST advisory board

Moore’s Law predicts the supply side of ICs, but the demand side can be understood as a “virtuous cycle” of technology advancement, lower costs, and rising demand leading to reinvestment. This same principle is in play for the emerging market for photovoltaics (PV), noted Gilad Almogy, senior VP of Applied Materials, at today’s opening keynote session for SPIE’s Advanced Lithography Conference in San Jose, CA.

Almogy began with a short review of IC market history. Gordon Moore’s “law” predicted the supply side, the number of transistors on a IC chip would double every 12-18 months. This, however, did not predict the demand side. As transistor output doubled, costs dropped, which led to lower prices for ICs. As prices dropped, markets expanded rapidly; applications spread from computers to notebooks to games, to innovative devices like the iPod, and many other uses. As IC markets grew, the industry invested in technology — and learned how to lower costs more. As costs went down, demand grew; this funded more investment in technology, which lowered costs, and so on. This “Virtuous Cycle,” Almogy noted, has continued In the IC market for over 40 years.

About 20 years ago the liquid crystal display (LCD) began a similar cycle, launched by the market for notebook computers. As demand picked up, output rose; this funded more investment in technology, which led to more cost reduction. By borrowing key technologies from the IC industry, the LCD business was able to launch faster. Unlike IC’s, the FPD market drove rapid cost reduction by increasing the size of the glass substrate — a new size every two years, sometimes sooner.

Applied sees the opportunity to launch the same virtuous cycle in the thin-film PV solar market, explained Almogy. The firm has taken many years of deposition tool and process development directly from their FPD business to the PV business. Large gen-8 glass sheets (about 2.2m × 2.5m) are being used to make large solar panels. Many process steps (and costs) are eliminated by Applied’s thin-film process. He pointed out that the world is near the “transition zone” where the cost of a solar watt will be equal to or lower than the cost of a fossil fuel watt. By launching in PV markets the same kind of virtuous cycle used in IC and FPD markets, the PV market should grow rapidly to a scale where it will be self-sustaining. — G.R.

(Photo source: SPIE)

JANUARY 21, 2009–WEST LAFAYETTE, IN–A new analysis method can detect the kidney-damaging chemical melamine, used to contaminate infant formula in China last September, at very low levels within a matter of seconds.

A research team at Purdue University created the analysis method to detect levels of melamine in the low parts-per-billion (ppb) in milk and milk powder in about 25 seconds.

An estimated 50,000 Chinese children were sickened and several died after drinking the melamine-contaminated formula. Melamine, which is used in plastics, was deliberately added to the formula to artificially bump up apparent protein levels.

The chemical also was found in the contaminated pet food produced in China responsible for the deaths of a reported 8,500 dogs and cats in the United States in March 2007.

The U.S. Food and Drug Administration (FDA) issued new guidelines in November limiting melamine in dairy products to 1 part-per-million (ppm) or less.

“This situation created an immediate need for an analytical method that is highly sensitive, fast, accurate, and easy to use,” says R. Graham Cooks, Purdue’s Henry B. Hass distinguished professor of chemistry, who led the team that developed the analysis method. “We took it as a challenge to use simpler instrumentation and to develop a faster method that allows the testing to be done on site and does not require pretreatment of samples.”

In addition to Cooks, the team includes Guangming Huang, a postdoctoral research associate, and Zheng Ouyang, an assistant professor of biomedical engineering. A paper detailing their work was published online in the journal Chemical Communications and will appear in the next issue of the journal.

“Even without direct contamination, trace amounts of melamine sometimes make their way into consumable products because melamine is used in manufacturing and is found in many packaging materials,” Cooks says. “At trace levels, the chemical is not known to be a health threat and has been deemed safe by the FDA. Our analysis provides a way to determine whether the amounts present exceed safe levels.”

The new method pairs mass spectrometry with a low-temperature plasma ionization probe technique.

Mass spectrometry is a commonly used analysis method known for its sensitivity and accuracy; however, most available mass spectrometers require that a sample be pretreated and remain in the controlled environment of a vacuum for analysis, Cooks says.

The Purdue team took advantage of the recent availability of new ambient ionization methods in which samples are examined in their native environment with little or no preparation, he says.

“Ambient ionization methods, such as the low-temperature plasma ionization we used, can greatly reduce the time-intensive and sometimes difficult requirements of mass spectrometers,” Cooks says. “The experiment can be done in a high-throughput fashion, at a rate of two samples per minute. This method provides the sensitivity, specificity, and the quantitative accuracy needed to meet the current urgent requirements for a simple and reliable melamine determination in complex mixtures.”

The method directs a collection of charged particles, or plasma, onto the sample using a slow stream of helium or other gas. The plasma reacts with the sample and ionizes, or gives its charge to, some of the molecules in the sample. The charge gives the molecules mass and allows them to be identified by a mass spectrometer. The ionized sample molecules are then vacuumed into a mass spectrometer for analysis. Heating the sample assists in ionization, according to Cooks.

During the experiments, a solid melamine-containing material was heated to approximately 340 degrees Fahrenheit. Liquids, such as milk, evaporated as they were heated and the residues were examined.

“There is a growing need in our society for detailed chemical information that calls for the special capabilities of mass spectrometers,” Cooks says. “Researchers are working to make these devices faster, easier to use, and more portable. Perhaps one day everyone will have a mass spectrometer to analyze whatever comes their way.”

The Cooks and Ouyang groups have created several portable miniature mass spectrometers, including the most recent 9-pound Mini11, which is equipped with capabilities for ambient ionization. The team next will try to incorporate the new analysis method into the capabilities of the Mini11.

The Office of Naval Research Research Tools Program funded their research.

Cooks is co-founder of Purdue’s Center for Analytical Instrumentation Development located at the Bindley Biosciences Center in Purdue’s Discovery Park and also is affiliated with the Purdue Cancer Center.

Indianpolis-based Prosolia Inc. has commercialized the related Cooks’ ambient ionization technology called desorption electrospray ionization, or DESI.

Source: Purdue University News Service

Visit www.purdue.edu

February 20, 2009: The European Commission approved $606 million in government aid to a nanotechnology program led by STMicroelectronics, according to a Reuters report.

The money will help pay for Europe’s Nano2012 strategic investment program aimed at producing the next generation of integrated circuits.

“The Nano2012 program to develop new technologies for the manufacture of semiconductors in Europe is in line with the EU’s major research objectives,” EU Competition Commissioner Neelie Kroes said in a statement. “Its positive effects will far outweigh any distortion of competition that may result from the aid.”