Sulfur Dioxide Contamination Analyzer Shipped (Press Release)

February 12, 2005

Particle Measuring Systems has shipped its first Sulfur Dioxide (SO2) analyzer that extends the capabilities of the AirSentry system for real-time monitoring of molecular contamination at ultra-low concentrations.

Molecular contamination monitoring of Sulfur Dioxide (SO2) is becoming a requirement in the semiconductor industry. In addition to the devastating results caused by its acidic nature on exposed product wafers, SO2 disrupts photolithography by reacting with bases such as ammonia, NMP, and amines to form ammonium sulfate, which deposits on and damages optical elements and lithography reticles, especially using 193 nm lithography. Over time, this contamination grows larger, becomes more opaque, and causes increasing transmission loss, among other effects. This increases the likelihood of critical dimension shifts, process yield loss, and equipment downtime.

The analyzer uses pulsed fluorescence technology to measure SO2 contamination. In the presence of UV light, SO2 molecules are excited. When the UV lamp is pulsed off, the excited SO2 molecules emit light at a specific wavelength as they decay to a lower energy state. The amount of emitted light is proportional to the SO2 concentration. In addition, the analyzer uses hydrocarbon filters and narrow bandpass optical filters, which allow the detector to see only the wavelength of the emitted light from the decaying SO2 molecules.

This analyzer can be coupled with other analyzers in the AirSentry-IMS System, allowing for real-time monitoring of SO2, ammonia, NMP, and Total Amines from a single unit. AirSentry's optional on-board calibration system insures accuracy and reduces maintenance costs by eliminating calibration costs. Capital costs are reduced by automated sampling from 16, 30, 45, or 60 user-defined locations with the integrated rotary sampling valves.

Particle Measuring Systems has 35 years experience designing, manufacturing, and servicing precision microcontamination monitoring instrumentation and software used for detecting contamination in air, liquids, slurries, gas streams, and vacuum processing environments as well as on surfaces.

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For more information contact:

Nina Akindele
Manager, Marketing and Communications
303.443.7100 ext. 258
nakindele@pmeasuring.com