MST’s Semiconductor Clients Use Control Networks to Achieve Dramatic Savings

Founded in Munich, Germany, in 1983, MST Measurement Systems is the world’s leading supplier of LonWorks-based toxic gas life safety systems. MST gas monitoring equipment is used for the detection and measurement of dozens of different toxic, corrosive, flammable, and explosive gases. MST Measurement is a division of MST Analytics, which develops, manufactures, and markets gas monitoring and control systems for the semiconductor, chemical, and petrochemical industries.

MST works closely with its customers in the semiconductor industry to provide maximum life safety protection and control strategies against hazardous gas leaks and releases. The company uses electrochemical sensor technology, sophisticated microelectronics systems, and a LonWorks architectural network from Echelon Corporation. By using an Echelon-based solution, MST Measurement easily reduces installation and associated costs by an impressive 40 percent.

Digital Platform Key to Protecting Chip Operators

According to Michael Severino, regional sales manager, “To significantly enhance our communications capability, we required a digital platform for our gas detection technology.” He noted that most gas detection equipment companies typically rely on an established 4-20mA analog output, which limits the information that can be sent from gas detection devices in the field. “We needed to extract more information, including the status of alarms, sensor cells, and general system status, in addition to the gas concentration levels.”

“The savings in installation and related costs can reach $3 million for a large site.”

A digital protocol allows MST to more quickly obtain real-time gas concentration values. “It is critical to know the exact gas concentrations in the field,” states Severino. “This is what ultimately determines the health and well-being of the operators engaged in the chip manufacturing process.” Severino adds that bidirectional communication was also important. “The ability to readily access and receive information from field devices plays a key role in reducing costs for our semiconductor customers.”

Solution Focuses on Lower Costs and a Safer Environment

During the search for a digital communications protocol, MST’s development team highlighted four primary goals. First, the installation costs associated with wiring the network needed to be reduced. The clean room environment of a semiconductor fabrication facility requires an environment that is far more sterile than that of an operating room. There can be no dust particles or contaminants of any kind. During the installation phase of a system, the engineers follow strict clean room procedures relating to equipment, work clothes, and body contaminants. As the installation progresses, and as the wiring becomes more complex, additional preparation time is required. “The ability to preinstall the network infrastructure can significantly reduce costs, since we do not need to spend as much time in the clean room,” comments Severino.

Flexibility is also a key factor for semiconductor customers. “Life safety systems must be able to cope effortlessly with the continual technological changes of the industry,” says Severino. The ability to distribute intelligence to the field devices can help simplify wiring requirements while providing the requisite flexibility.

The conventional system architecture of an analog communications relies on a central controller. “A single point of failure is too great a risk, given the need to protect the health and safety of the operators,” comments Severino. MST’s solution was to distribute the intelligence to the field devices.

The final goal was to ensure the accuracy and reliability of the information communicated from the field. “Based on industry standards, and the need to meet various building and fire codes, it was imperative that the communication platform be very safe and fault tolerant,” emphasizes Severino. “With a truly distributed network architecture, data integrity must be guaranteed. This is possible with the full seven-layer OSI specification.”

Echelon Products Permit Flexible Monitoring Approach

After evaluating numerous options, MST selected the LonWorks control network platform from Echelon. “We felt that the networking solution from Echelon best suited both our needs and our customers’ requirements,” states Severino. Flexibility is very important to MST, since the company’s toxic gas monitoring and control systems are tailored to the specific requirements of its various semiconductor clients.

A typical infrastructure employs a free topology backbone with individual subnets. Each subnet, which is partitioned from the backbone with a router, contains the necessary hardware (nodes) for a designated area of the fabrication facility. MST also uses a PCLTA card from Echelon to interface with MST’s DVS visualization software package. The resulting control network can include a combination of different types of nodes. Each node—satellite gas detector, relay module, digital input module, or supervisory bus switch (SBS) module—is an intelligent device equipped with a Neuron Chip processor and transceiver. MST’s satellite gas detectors are continuous real-time gas-monitoring instruments used for the detection of a wide range of toxic, corrosive, and combustible gases. MST uses the Neuron Chip’s timing mechanism to initiate self-diagnostics in the field gas detection devices. The detectors receive power and data on a common twisted pair with virtually no topology restrictions.

White Oak Semiconductor, MST’s largest LonWorks installation with 1,000 nodes, is a typical implementation. The LonWorks architecture connects satellite gas detectors, relay output modules, and digital input modules. The network is completely redundant and distributed on two levels of the semiconductor manufacturing building.

The toxic gas functional shutdown matrix developed by White Oak binds satellites and digital input modules with different numbers of relay output modules. A toxic gas detection can set off different safety responses, including automatic gas shut-off at the source, gas shut-off to a particular process or tool, and building evacuations. The network also monitors the well-being of the specific on-board fire suppression equipment installed on process tools.

Large Fabrication Site Savings Can Reach $3 Million

Echelon’s LonWorks products have helped MST produce dramatic savings for its semiconductor clients. For example, free topology architecture requires only one single twisted-pair connection to each gas detection device. This permits quick online installation, relocation, and removal of gas detectors or other devices without compromising the safety, system control, or monitoring at any other connected “online” device.

As a result, MST’s customers can save up to 40 percent in installation and associated costs. “On average, we save $2,000 on each gas detection device,” states Severino. Depending on the size of the fabrication facility, the savings range from $20,000 for a 10-device installation to $3 million for a large site with 1,500 devices.

The Echelon-based solution also eliminates needless evacuations and site shutdowns. “This is a tremendous benefit for our customers,” says Severino. “Each eight-hour shift in a large facility can manufacture up to $1 million of products. All work-in-progress must be scrapped during evacuations.” Echelon’s LonWorks products provide the functionality and savings MST’s semiconductor clients require. For MST, such effective solutions are literally life savers.

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