NEW EXCIMER LASER MEASUREMENT SERVICES AT NIST.

NIST recently has developed the capability to accurately measure pulse-energy density of deep ultraviolet (DUV) radiation produced by excimer lasers. This new capability now is being used to provide dose (i.e., energy density) measurement services for small-area detectors like those used in high-resolution semiconductor photolithography systems and other excimer laser applications. NIST is now offering absolute responsivity calibrations of laser dose meters at the laser wavelength of 193 nm. Additional excimer laser wavelengths will be added to this service in the near future.

The dose measurements are performed using a beam-splitter-based calibration system in which a spatially uniform beam from an ArF excimer laser is generated using a special beam homogenizer. The beam propagation properties, including uniformity or homogeneity, are fully characterized with a state-of-the-art beam profile measurement system based on a pyroelectric camera array. This uniform beam is then used to irradiate a NIST-calibrated aperture placed immediately in front of the test detector. Measurement traceability for these calibrations stems from an electrically Calibrated, primary standard calorimeter developed by NIST scientists.