Smart laser with automated beam quality control
AssigneeCymer, Inc.
InventorsFrederic G. Erie, Jesse D. Buck, Palash P. Das
Life of this patent
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Abstract
A smart laser having automatic computer control of pulse energy, wavelength and bandwidth using feedback signals from a wavemeter. Pulse energy is controlled by controlling discharge voltage, wavelength by controlling the position of an RMAX mirror in a line narrowing module and bandwidth is controller by adjusting the curvature of a grating in the line narrowing module. Preferred embodiments include automatic feedback control of horizontal and vertical beam profile by automatic adjustment of a prism plate on which beam expander prisms are located and automatic adjustment of the RMAX tilt.
Claims13
A smart narrow band electric discharge laser for producing an output laser beam said laser comprising:
- A) a laser from;
- B) a laser chamber adjustably mounted in said frame;
- C) a laser gas contained within said chamber;
- D) two elongated spaced apart electrodes contained within said chamber, said electrodes and laser gas between them defining a gain medium;
- E) an output coupler;
- F) a line narrowing module comprising a prism beam expander, an RMAX mirror and a bendable grating defining a grating curvature, said line narrowing module and its optical components and the output coupler defining a resonance cavity;
- G) a wavemeter for detecting laser beam parameters including at least pulse energy, wavelength and bandwidth;
- H) a computer controller;
- and
- I) a grating curvature positioner controlled by said computer controller to adjust the grating curvature based on bandwidth information provided to said computer controller by said wavemeter.
Dependencies are inferred from the claim text.