CONTAMINANT DETECTION METROLOGY SYSTEM, LITHOGRAPHIC APPARATUS, AND METHODS THEREOF

摘要

A system can include a light source configured to illuminate a surface of a pellicle, a scanner configured to scan the surface of the pellicle; a spectrometer configured to measure a Raman spectra of a reference signal and a test signal, the reference signal being based on a measurement from a surface of the pellicle and/or a reticle and the test signal being based on the illuminated surface of the pellicle, and a processor. The processor can be configured to determine a difference between the Raman spectra of the reference signal and the lest signal and identify a presence of a contaminant on the surface of the pellicle in response to detecting a deviation in the Raman spectra of the reference signal and the test signal.