Flow shaping electrode with erosion pad for gas discharge laser

Abstract

An excimer laser with a laser chamber containing a circulating laser gas containing fluorine and a set of long life electrode structures. At least one of the electrode structures has an erosion pad and a cross section shape designed to provide in conjunction with other chamber structure a gradual increasing flow cross section between the discharge region and the circulating tangential fan blade. In a preferred embodiment, electrode lifetime is increased by annealing the erosion rod after it is are machined. This annealing relieves the surface stress caused by the machining operation and reduces the exposed metallic grain boundary length per unit area on the surface of the electrodes, which provides substantial reduction in erosion caused by fluorine chemical attack. Annealing after machining also reduces the stress throughout the bulk of the electrode material. In preferred embodiments the anode is a copper-aluminum alloy and the cathode is a copper-zinc alloy.

Dependencies are inferred from the claim text.