EUV pellicle qualification on transmission and reflectance

Abstract

RI Research Instrument’s EUV pellicle transmission qualification tool EUV-PTT uses effective inband EUV measurement which is spectrally filtering emission of the EUV-Lamp to 2% bandwidth at 13.5 nm for measuring as seen by the scanner . Images of about 20x20 mm2 are recorded in less than 5 seconds. A full pellicle characterization with < 60 images taken is accomplished in less than one hour. The first prototype of the EUV-PTT is in production quality control since nearly one year at our customer and achieving targeted quality in measurement and cleanliness and meets uptime specifications. Amongst additional aspects to be addressed in quality control is the reflection from the pellicle, which - in worst case - may impair the printing performance in the scanner. Hence, recently, we have performed concept studies on applying the PTT technique to carbon nano tube pellicles and on measuring the reflectance of low reflectance samples are reported. The latter is heavily demanding as reflectances in the range of 0.02 % were measured with sensitivities and reproducibilities in the range of 0.002 %.