Semiconductor, Flat Panel Display Industries Seize Lion`s Share of Monitoring Business
There are sensors out there for every environmental factor but the real trick is collecting, reading and interpreting the data and having it at your fingertips.
By Lisa A. Coleman
If a user can easily view, analyze and manipulate data via a cleanroom monitoring system, it`s simpler to solve problems that may arise in the environment. Critical environments can be monitored by sensors that detect ionization levels, particles, toxic gases and other environmental factors. However, integrating these systems into one is what a real-time facility monitoring system does.
The monitoring market is growing, just take a look at the particle monitoring instrumentation market. Particle counters are often a part of the overall facility monitoring system, however this instrumentation is also sold by itself. It`s no surprise that particle monitoring instrumentation for Class 1 to 10 cleanrooms was a $121,249,000 market in 1995, according to The McIlvaine Co. (Northbrook, IL). In 2000, these figures are expected to skyrocket to $341,533,000, a leap of $220,284,000 or about 180 percent! In addition, it`s predicted that in 2000 the lion`s share of monitors will be used in Class 1 to 10 critical environments–with the Asian market accounting for more than $146,122,000 in orders.
According to The McIlvaine Co., in 1995, monitoring orders for Class 1-10 cleanrooms in the semiconductor industry were $63.24 million worldwide. In 2000, the semiconductor industry alone is predicted to increase its spending to $221.48 million.
User needs
Users need reliable facility monitoring systems providing accurate, immediately accessible data. “What the industry wants,” says John Urmson, president of TeloSense (Fremont, CA), “is for these absolutely necessary functions to be as transparent as possible–flawless, automatic, and not any trouble to maintain. Always there, always working, and something you don`t have to worry about. It should be like electricity, but more reliable!” Urmson also notes that the industry is asking for more automation, remote operation, and direct integration into the facilities control schemes “so personnel are only involved when a problem or emergency occurs,” he adds.
Advances in distributed control and monitoring technology have made it possible for real-time critical environment monitoring to be developed.
Users need to keep these factors in mind when choosing a facility monitoring system.
Facility monitors
Finding a facility monitor system that meets the factors listed above may be a bit challenging. According to TeloSense`s Urmson: “The most cost effective way to fulfill this set of requests is based on centralized monitoring with analytical systems that do not involve consumables, coupled with a setup that delivers multiple, continuous sample streams to instruments that are self-checking, integrated into the facilities and do not require constant maintenance.”
TeloSense supplies air monitoring equipment and related services to the industry. Among its products are toxic gas, air composition and other gas sensing monitors. Its Air Composition Monitor (ACM) is now available with Emergency/Guard Station (EGS) software and LAN support. The ACM uses infrared analysis to detect low-level concentrations of nearly all airborne chemicals used in a semiconductor fab. ACM`s EGS software provides data manipulation and information processing at the ACM system level, allowing the ACM to send various types of useful information to targeted groups in the fab instead of just data. Information can be sent to safety personnel, the local security guard, the ERT, and the facilities monitoring group based on their predefined needs.
Plant personnel tell the ACM what standard response procedures and recommendations they want followed for both routine events and potential emergencies. For example, if an emergency gas leak is detected, the ACM notifies the security guard and presents the guard with the predefined recommended action list for the problem it detects. Simultaneously, the ACM shuts down the source if possible and sets off an audible alarm if the leak gets into the workplace. Information about the air composition is also sent to plant personnel and the ERT. “An extra benefit of the analytical system approach is that the gases monitored for can be changed via software, and unknown odors and leaks can be analyzed and identified even if the gas involved is not on the list of gases routinely monitored,” says Urmson.
Statistical process control
Another type of system is from Coventry Cleanroom Products (Kennesaw, GA). Its Cleanroom Monitoring System (CMS) uses statistical process control techniques which, according to Coventry, exceed the requirements of Federal Standard 209E, when it is used as a monitoring method. The CMS provides not only a pictorial indication of room cleanliness but also a numerical value that can be used for quality comparison. According to Stewart F. Scott, cleanroom engineering manager for Coventry, there are three main differences between CMS and 209E. First, CSM specifies that the air quality must be monitored daily while the cleanroom is in operation. “A particle concentration taken at rest will not indicate the effectiveness of the cleanroom protocol and the cleanliness of the manufacturing process,” says Scott. Federal Standard 209E doesn`t specify a time interval for monitoring or when the test is to be conducted.
Second, Coventry`s CSM methodology specifies that the room must have a process capability (Cpk) equal to or greater than 1 at the designated upper specification limit (USL). The Cpk stipulation requires the cleanroom operate 99.87 percent of the time within its specification or within its three sigma limits. This value states how well the room is being maintained to the established specifications and the efficaciousness of the cleanroom protocol. With it, an engineer could easily determine if the manufacturer is meeting its own specs, according to Scott.
The USL of Coventry`s CMS is determined from table 1 of 209E. It is the particulate concentration listed in the table at the specified classification and micron size. For example, a Class 10 (M2.5) operational room at 0.3 micron would have an USL of 30 particles/ft3. This is not the same as 209E, which states that no average reading can exceed the concentration listed in table 1. There are no upper specification limits listed in 209E for a single data point, only for average particle concentration at a location. The federal standard allows particle concentrations to exceed the values listed in the table as long as the average of the sample points is below the table listed value. Therefore, according to Scott, when using 209E as a monitoring method, it is possible to record particle concentrations in a cleanroom that exceed the listed concentration as long as the averages of the readings remain below the limit. The CMS does not use averages to determine location particle concentration or room classification. It uses individual data points of the sample to demonstrate protocol control and air cleanliness.
And, third, Coventry collects a specified number of particle readings or data points at each sample location.
Open architectures
Lighthouse Associates (Milpitas, CA) has a fully distributed modular system that offers networking support and full compatibility with all sensor manufacturers. The Lighthouse Monitoring System (LMS) is a completely automated facility monitoring system that works with a variety of sensors. LMS signals alarms, pagers, and displays real-time data in a wide variety of formats, including graphs, charts, data tables, SPC graphs and maps. LMS can serve as an engineering tool to provide continuous monitoring of cleanroom conditions, to act as an early warning system, or to analyze historical data for defect analysis, according to the company.
LMS modular, open architecture allows it to monitor a few sensors in one cleanroom, or form a fully integrated network worldwide. According to Lighthouse, LMS supports any sensor. It also works with voltage, current, frequency-based, and serial sensors (such as RS-232, RS-422, and RS-485) to monitor particle counts, temperature, relative humidity, differential pressure, resistivity, pH, vibration, conductivity, air velocity, TOC, DI water, in situ, and more. Each sensor can be individually configured. In addition, a building floor plan–in LMS–shows sensor locations throughout the plant. The sensors change colors to signal warning and alarm conditions. Detailed sensor information is available. Additional sensors can be located anywhere in the world.
The primary modules in the basic LMS system are the Engineering Control Station (ECS) and the Sensor Interface Unit (SIU). These components can monitor one or more facilities or areas in any one location. The SIU controls the data collection interface to the sensors. The SIU`s processor and LMS software allow the SIU to monitor sensors with different interfaces and to manage data collection. The ECS is a microcomputer system that runs LMS software in Windows. One ECS workstation can manage multiple SIUs.
The newest product from Teletrol Systems, Inc. (Manchester, NH) is the Integrator, a facility monitoring and control system for environmental systems supporting cleanrooms. Applications for the system are medical equipment manufacturing, semiconductor fabrication, pharmaceutical manufacturing and hospital operating rooms. The Integrator system consists of a family of controllers for use on all types of HVAC equipment, from packaged, unitary systems to large, built-up systems. Individual controllers connect together via a high-speed network for system-wide data sharing, alarming and coordinated control. Telephone modem support is also provided.
Teletrol`s Integrator also can be used for the following controls: precise temperature, pressure and humidity; interlocking of pressure controls with door operation; interface with smoke control systems; monitoring of particulate counts via direct communication with stand-alone particle counter systems; monitoring of HEPA filter status via differential pressure sensors; display of operating data via a single graphical user interface; and alarming and data logging.
Another company that provides centralized facility monitoring is Process Control & Engineering (PC&E; Auburn Hills, MI). Its system monitors relative humidity, temperature, airflow, air balance with respect to the surrounding, particle count, access door integrity, and other important environmental factors. PC&E`s system is modular with distributed data acquisition/control modules (DACs) for acquiring data from local sensors and activating local controls. A CPU is the supervisory station for all distributed DAC modules to display the data for monitored parameters on a facility map in real time, at a central location. Its air balance monitoring (ABMS) system is an alternative to pressure monitoring sensors that provides a much higher accuracy particularly for cleanrooms that must be maintained negatively pressurized with respect to the surrounding, according to PC&E. The system will have capabilities of alarming, data logging, real-time and historical trending, communication of information over networks or telephone lines.
Monitor, monitor, monitor
The Manufacturing Technology Division of The Fidelis Group, Inc. (Newton, MA) manufactures the RoomWatch System–a self-contained PC and sensor-based system which alarms critical cleanroom parameters. RoomWatch provides tabulated and graphic data on performance, and alarms in anticipation of product deterioration or failure. Measurements can be continually monitored and assessed, and cover a wide variety of conditions such as back-pressure, relative humidity, laminar airflow, temperature, vibration, power line characteristics, particulate and the presence of toxic gases. The measurement data can be graphically displayed or presented in a printed form. A “call-up” option is available to notify several remote operations if an environmental failure has occurred.
The FMS-1000 Facility Monitoring System from Biotest Diagnositics Corp. (Denville, NJ) can monitor and control a network of up to 32 APC-1000 particle counters with a PC-compatible computer. Each APC-1000 can count particles in four size ranges simultaneously, while also measuring temperature and relative humidity. The FMS-1000 can be configured to sample all locations at predetermined times or any individual location for a spotcheck. The data is stored in a file that can be imported into a spreadsheet program for analysis. Also, the FMS-1000 software alerts users if readings exceed cleanroom classifications according to Federal Standard 209E.
RION Company Ltd. (Tokyo, Japan) along with MGN International, Inc. (San Jose, CA) are introducing a new real-time liquid particle sensor, the KL-28A. Optional with this sensor is the LMS Lite System, a real-time data collection and monitoring system. The Lite System uses a MS-Windows interface, continuous data recording, central viewing, and data-to-event correlation–correlating particle and environmental data to events such as employee shifts, preventative maintenance, protocol changes, etc.
Particle Measuring Systems (Boulder, CO) has developed a software package, Facility-View, that provides an account of all environmental conditions within a cleanroom. Facility-View is a MS-Windows-based program that lets users view simultaneously tabular displays, real-time or retrieval time plots, 3-D histograms, status conditions, even logs and a facility map for every monitoring instrument. Networking capabilities are available. Each instrument can have user-defined sample intervals and be grouped to an alarm device.
The software program also has a paging function that uses a modem to send numerical codes to specified pagers to notify of alarm events or other occurrences. Other features include calculation capabilities that enable an operator to combine any number of sample points using a mathematical or logical expression to generate a new sample point. Facility-View also provides data management functions such as the ability to control the amount of data to be stored for each monitoring instrument. All data is automatically compressed into a format that reduces storage requirements.
Clestra Cleanroom, Inc. (N. Syracuse, NY) recently upgraded its Programmable Logic Controller (PLC) system for “validation guaranteed” facilities in the pharmaceutical and biotechnology industries. The PLC system provides 24-hour automated computer supervision, including remote capability, and generates hourly, daily and weekly trend charting and alarm reporting. Detailed monitoring and recording of critical data helps meet FDA validation requirements. Clestra`s PLC system assists in FDA validation by providing the tools necessary to save outputs and observe system response for IQ/OQ protocol execution.
Non-volatile residue monitor
Femtometrics (Irvine, CA) has a real-time Non-Volatile Residue (NVR) monitor which is specifically designed for facility monitoring. Multiple sensor heads can be connected to a single control unit via RS-485 hardware. The control unit will have the ability to sound an alarm if an out-of-specification contamination condition is detected. The alarm point levels are set by the user in the embedded software. Real-time graphical display software will be available in order to actively monitor molecular contamination graphically in real-time during critical processing steps.
This June, Femtometrics plans to introduce a small, completely self-contained battery operated real-time NVR monitor. This system is designed to be programmed by the user to “wake-up” and make a NVR measurement, store the time, date and contamination level then go back to “sleep” until the next measurement is scheduled to be made. “This will enable contamination control engineers to make specific strategic measurements in the fab without the need to install a complete instrument which requires space and usually disrupts the work being performed in the critical area,” says William D. Bowers, PhD and president of Femtometrics.
The real-time NVR monitor can also be used to measure the level of molecular contamination in high-purity semiconductor process gases and solvents. In addition, Femtometrics has also developed and engineered a gas introduction system to sample process gases for condensable contaminants. According to Bowers, Femtometrics has also demonstrated the ability to measure sub-ppm levels of NVR in high-purity solvents used by the semiconductor industry. Femtometrics is currently engineering the sample introduction system and plans to introduce this instrument to the market in mid-1996. The instrument requires approximately 1 ml of sample and takes 10 to 15 minutes per analysis. The analysis time will be reduced to approximately 5 minutes by the end of this year, says Bowers. n
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The McIlvaine Co. predicts that orders for monitoring instruments will increase dramatically by the year 2000.
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Coventry Cleanroom Products has de veloped a Clean room Monitoring System (CMS) which uses stat istical process control techniques that exceed the requirements of Federal Standard 209E when it is used as a monitoring method.
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TeloSense Corp.`s Air Composition Monitor (ACM) uses infrared analysis to detect low-level contamination of nearly all airborne chemicals used in semiconductor fabs. ACM is available with emergency/guard station software and LAN support.
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The Manufacturing Technology Division of the Fidelis Group, Inc.`s RoomWatch is a self-contained PC- and sensor-based system that provides tabulated and graphic data on performance and alarms in anticipation of product deterioration or failure.
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Teletrol`s Integrator facilities monitoring and control system for environmental systems supporting cleanrooms.
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Particle Measuring Systems software package, Facility View, provides a comprehensive account of all environmental conditions within a cleanroom. Users can view tabular displays, real-time or retrieval time plots, 3-D histograms, status conditions, etc.
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Femtometrics real-time Non-Volatile Residue (NVR) monitor for airborne molecular contamination. A new, enhanced version of the NVR Monitor will be available this month.