Evaluation of molecular contaminants in the micro-environment between photomask and pellicle using analysis tool

摘要

The problem of haze and related defects become more serious as the dimension of lithography becomes smaller. Ithas been reported that the causes of haze defects are organic and inorganic molecular contamination deposited on masksurface. These haze problems influence the productivity of lithography process, but the formation mechanism of hazehas not been clear. So it is important to understand chemical composition and formation mechanism of haze to preventit. To analyze the chemical composition, several analytical techniques are useful, that is, ion chromatography (IC) orgas chromatography mass spectrometer (GC/MS) after liquid extraction of mask surface, surface analysis such astime-of-flight secondary ionization mass spectrometry (TOF-SIMS), X-ray photon spectrometry (XPS) and so on.However, these techniques are all destructive methods and are difficult to evaluate the airborne molecular contaminants(AMCs) with high sensitivity between mask and pellicle. We have successfully developed new and sensitive analysistool consists of two parts and applied it for the evaluation of micro-environment between photomask and pellicle. Oneis the equipment to collect AMCs effectively, that provides diagonal two holes with needles on the pellicle to collect thegas while ventilating the high-purity nitrogen gas. The other is sampler which is named BremS™ to collect andmeasure exhausted AMCs in the space with high sensitivity. We applied this method to masks with different exposuredosage rate and introduce the usefulness of our method.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.