Laser gas supply path structure in an exposure apparatus

摘要

A gas supply path structure forms a fluid path for allowing a laser gas to flow into or out of a pair of fluid inlet and outlet 11a and a laser gas is controlled to a predetermined subsonic speed at a throat portion. Gas supplies for controlling the speed of the gas are connected each to the fluid inlet and to the fluid outlet of the gas supply path structure and, together with a cooling device, compose a circulation system for controlling the speed and pressure of the laser gas at the fluid inlet and/or at the fluid outlet.