Back to results
US 5,856,991 AGranted
Very narrow band laser
AssigneeCymer, Inc.
InventorAlexander I. Ershov
Life of this patent
Estimating the term…
Abstract
A very narrow band excimer laser. The very narrow bandwidth is achieved by using an etalon as an output coupler in combination with a line narrowing element located at the rear of the laser. Preferred embodiments are capable of producing 10 mJ laser pulses at 1000 Hz with a 95% integral bandwidth of less than 1.5 pm.
Claims15
A very narrow band excimer laser comprising:
- A. a laser chamber containing:
- (1) two elongated electrodes,
- (2) at least one preionizer, and
- (3) a laser gas,
- B. a line-narrowing unit positioned to accept a portion of the light generated in the laser chamber, narrow its spectrum to produce line-narrowed light, and return it to the laser chamber, said line narrowing unit comprising:
- (1) at least one beam expanding prism,
- (2) a grating, and
- (3) a grating tuning means for tuning the grating;
- C. an output coupler comprising an etalon, said output coupler being positioned to reflect a portion of light generated in said laser chamber and to output a portion of the light;
- wherein both the grating and the etalon are arranged to provide at least approximately maximum reflection into the chamber at a single desired wavelength.
7 more elements
A very narrow band KrF excimer laser comprising:
- A. a laser chamber comprised of fluorine compatible materials and containing:
- (1) two elongated electrodes,
- (2) at least one preionizer, and
- (3) laser gas defining a total pressure and comprised of krypton, fluorine and a buffer gas, said fluorine having a partial pressure of less than 0.08 of the total pressure;
- B. a tunable line narrowing unit comprised of:
- (1) at least one beam expanding prism, and
- (2) a tunable grating;
- C. an output coupler comprising an etalon;
- wherein both the grating and the etalon are arranged to provide at least approximately maximum reflection into the chamber at a single desired wavelength.
6 more elements
Dependencies are inferred from the claim text.