Abstract: A method of extreme ultraviolet lithography includes: generating within a source vessel extreme ultraviolet (EUV) light by striking a stream of droplets of target material shot across the source vessel with pulses from a laser to create a plasma from which EUV light is emitted; directing the generated EUV light out of the source vessel through an intermediate focus cap along a pathway toward a reticle of a scanner; creating a longitudinal mechanical wave extending across the pathway; and exposing a photoresist layer on a semiconductor substrate to pattern a circuit layout by the generated EUV light.