It is common in extreme ultraviolet lithography (EUV) scanners for extremely clean dry air (XCDA) in-scanner cleaning to be performed in order to ensure cleanliness of parts. Cleaning such as this can be performed to reduce contamination of critical parts such that the system has the required defectivity performance (PRP). It is particularly important to use a cleaning method such as this to reduce contamination after system assembly or after the replacement of parts. For example, such cleaning might be performed in the reticle mini-environment (RME). A nozzle may be present in the scanner to create a protective hydrogen (H2) gas layer below the reticle in order to protect it against particles during exposure. The same nozzle may be used during cleaning of the scanner, for example to clean the reticle masking (REMA) blades and the reticle stage (RS). The disadvantage of having a single nozzle to perform these dual functions is that both functions, H2 protection and XCDA cleaning, can have conflicting requirements on the design of the nozzle. This means that the nozzle design will be a compromise between the two sets of requirements and/or the nozzle will not be as effective as desired in one or both functions.
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