Research Disclosure

摘要

This research disclosure relates to a method of reducing contamination of pans of an apparatus. The apparatus may be a lithographic apparatus. The Lithographic apparatus may be an extreme-ultraviolet (EUV) lithographic apparatus. In a lithographic apparatus an illumination system conditions a beam of radiation and a patterned mask is illuminated with the conditioned beam of radiation. The patterned mask imparts a pattern to the conditioned radiation beam to form a patterned radiation beam. The patterned radiation beam is projected onto a substrate via a projection system in order to transfer the pattern onto the substrate. EUV lithographic apparatus use EUV radiation to form the pattern on the substrate. The EUV radiation may contribute to the generation of contamination within the lithographic apparatus. For example, the EUV radiation may interact with matter present in the lithographic apparatus (e.g. small amounts of gas) to form a plasma. The plasma may provide suitably strong electromagnetic forces to release contaminant particles from surfaces within the lithographic apparatus. In general, increasing the power of the EUV radiation increases the number of particles that are released from surfaces by EUV generated plasma. The contaminant particles may be transported to and be incident upon sensitive optical surfaces. For example, contaminant particles may be incident upon the reticle. Said contaminant particles may be imaged onto rhc substrate and disrupt the desired projected pattern, resulting in a defective product being manufactured by the lithographic apparatus. As another example, contaminant particles may damage parts of the lithographic apparatus (e.g. they may rupture a pellicle that protects the reticle), thereby increasing the frequency of maintenance activity and reducing a throughput of the lithographic apparatus.