Lithography laser with beam delivery and beam pointing control
First Claim
1. A modular, narrow band, high repetition rate ultraviolet laser light source for providing light in the form of laser output light pulses to a light receiving location in a production line machine comprising:
- A) a laser unit comprising;
1) a discharge chamber containing;
a) a laser gas and b) a pair of elongated spaced apart electrodes defining a discharge region in which said laser gas is discharged, 2) a gas circulation means for producing sufficient gas movement of said laser gas in said discharge region to clear from said discharge region, following each laser gas discharge, substantially all discharge produced ions prior to a next laser gas discharge when operating at a laser output light pulse repetition rate in the range of 2,000 pulses per second or greater, 3) a heat exchanger system removing heat energy from said laser gas, so as to maintain the temperature of said laser gas within a desired range, and 4) an electrical pulse power system providing electrical pulses to said pair of electrodes sufficient to produce laser output light pulses at rates of about 2,000 pulses per second or greater with precisely controlled pulse energies in excess of about 5 mJ, and;
B) a beam delivery unit comprising a beam path enclosure structure providing a laser output light pulse beam path, from a laser beam output port located on said laser unit to a remote laser beam output port at a terminus of said beam delivery unit;
C) a beam pointing means with feedback control for controlling the position and angle of said laser output light pulse beam at said remote laser beam output port;
D) a laser beam measurement means and control means for measuring pulse energy, wavelength and bandwidth of the laser light output pulses produced by said laser unit and controlling the laser output light pulses with a feedback controller; and
E) a purge means for purging said beam path enclosure structure.
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Accused Products
Abstract
The present invention provides a modular high repetition rate ultraviolet gas discharge laser light source for a production line machine. The system includes an enclosed and purged beam path with beam pointing control for delivery the laser beam to a desired location such as the entrance port of the production line machine. In preferred embodiments, the production line machine is a lithography machine and two separate discharge chambers are provided, one of which is a part of a master oscillator producing a very narrow band seed beam which is amplified in the second discharge chamber. This MOPA system is capable of output pulse energies approximately double the comparable single chamber laser system with greatly improved beam quality. A pulse stretcher more than doubles the output pulse length resulting in a reduction in pulse power (mJ/ns) as compared to prior art laser systems. This preferred embodiment is capable of providing illumination at a lithography system wafer plane which is approximately constant throughout the operating life of the lithography system, despite substantial degradation of optical components.
89 Citations
80 Claims
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1. A modular, narrow band, high repetition rate ultraviolet laser light source for providing light in the form of laser output light pulses to a light receiving location in a production line machine comprising:
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A) a laser unit comprising;
1) a discharge chamber containing;
a) a laser gas and b) a pair of elongated spaced apart electrodes defining a discharge region in which said laser gas is discharged, 2) a gas circulation means for producing sufficient gas movement of said laser gas in said discharge region to clear from said discharge region, following each laser gas discharge, substantially all discharge produced ions prior to a next laser gas discharge when operating at a laser output light pulse repetition rate in the range of 2,000 pulses per second or greater, 3) a heat exchanger system removing heat energy from said laser gas, so as to maintain the temperature of said laser gas within a desired range, and 4) an electrical pulse power system providing electrical pulses to said pair of electrodes sufficient to produce laser output light pulses at rates of about 2,000 pulses per second or greater with precisely controlled pulse energies in excess of about 5 mJ, and;
B) a beam delivery unit comprising a beam path enclosure structure providing a laser output light pulse beam path, from a laser beam output port located on said laser unit to a remote laser beam output port at a terminus of said beam delivery unit;
C) a beam pointing means with feedback control for controlling the position and angle of said laser output light pulse beam at said remote laser beam output port;
D) a laser beam measurement means and control means for measuring pulse energy, wavelength and bandwidth of the laser light output pulses produced by said laser unit and controlling the laser output light pulses with a feedback controller; and
E) a purge means for purging said beam path enclosure structure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 36, 37)
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20. A very narrow band two chamber high repetition rate gas discharge laser system for providing light in the form of laser output light pulses to a light receiving location comprising:
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A) a first laser unit comprising;
1) a first discharge chamber containing;
a) a first laser gas and b) a first pair of elongated spaced apart electrodes defining a first discharge region where said first laser gas is discharged, 2) a first fan producing sufficient gas movement of said first laser gas in said first discharge region to clear from said first discharge region, following each laser gas discharge, substantially all discharge produced ions prior to a next laser gas discharge when operating at a discharge rate in the range of 4,000 discharges per second or greater, 3) a first heat exchanger system removing at least 16 kw of heat energy from said first laser gas, 4) a line narrowing unit narrowing the spectral bandwidth of said first laser light output pulses produced in said first discharge chamber;
B) a second laser unit comprising;
1) a second discharge chamber comprising;
a) a second laser gas, b) a second pair of elongated spaced apart electrodes defining a second discharge region where said second laser gas is discharged, 2) a second fan producing sufficient gas movement of said second laser gas in said second discharge region to clear from said second discharge region, following each laser gas discharge, substantially all discharge produced ions prior to a next laser gas discharge when operating at a laser gas discharge rate in the range of 4,000 laser gas discharges per second or greater, 3) a second heat exchanger system removing at least 16 kw of heat energy from said second laser gas;
C) an electrical pulse power system providing electrical pulses to said first pair of electrodes and to said second pair of electrodes sufficient to produce said gas discharges in each of said first and second discharge chambers at rates of about 4,000 gas discharges per second with precisely controlled pulse energies in excess of about 5 mJ;
D) a pulse stretcher for increasing laser output light pulse duration of said second laser output light pulses produced in said second discharge chamber;
E) relay optics directing said first laser output light pulses produced in said first discharge chamber through said second discharge chamber to produce amplified second laser output light pulses;
F) a beam delivery unit comprising a beam pat enclosure structure providing a laser output light beam pat from said pulse stretcher to a laser output light beam output port at a terminus of said beam delivery unit said beam delivery unit further comprising;
a beam pointing means with feedback control for controlling the position and angle of the beam of said laser output light pulses at said output port at said terminus; and
G) a laser beam measurement means and control means for measuring pulse energy, wavelength and bandwidth of said laser output light pulses produced by said laser system and controlling said laser output light pulses with a feedback controller. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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38. A beam delivery unit for delivering a light beam from a laser light source to a light receiving location comprising:
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A) a beam path enclosure structure providing an enclosed beam path from an output port of said light source to an output port of said beam delivery unit at a terminus of said beam delivery unit, B) a beam pointing means with feedback control for controlling the position and angle of said laser light beam at said output port of said beam delivery unit;
C) a laser light beam measurement means and control means for measuring pulse energy, wavelength and bandwidth of laser output light pulses produced by said laser light source and controlling said laser output light pulses wit a feedback controller; and
D) a purge means for purging said beam path enclosure structure. - View Dependent Claims (39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49)
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50. A modular, narrow band, high repetition rate ultraviolet laser light source for providing light in the form of laser output light pulses to a light receiving location in a production line machine comprising:
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A) a first laser unit comprising;
1) a first discharge chamber containing;
a) a first laser gas and b) a first pair of elongated spaced apart electrodes defining a first discharge region in which said first laser gas is discharged, 2) a gas circulation means for producing sufficient gas movement of said first laser gas in said first discharge region to clear from said first discharge region, following each laser gas discharge, substantially all discharge produced ions prior to a next laser gas discharge when operating at a laser output light pulse repetition rate in the range of 2,000 pulses per second or greater, 3) a first heat exchanger system removing heat energy from said first laser gas, so as to maintain the temperature of said first laser gas within a desired range, and B) a second laser unit comprising;
1) a second discharge chamber containing;
a) a second laser gas and b) a second pair of elongated spaced apart electrodes defining a second discharge region in which said second laser gas is discharged, 2) a gas circulation means for producing sufficient gas movement of said second laser gas in said second discharge region to clear from said second discharge region, following each laser gas discharge, substantially all discharge produced ions prior to a next laser gas discharge when operating at a laser output light pulse repetition rate in the range of 2,000 pulses per second or greater, 3) a second heat exchanger system removing heat energy from said second laser gas, so as to maintain the temperature of said second gas within a desired range, and C) an electrical pulse power system providing electrical pulses to said first and second pairs of electrodes sufficient to produce laser output light pulses at rates of about 2,000 pulses per second or greater with precisely controlled pulse energies in excess of about 5 mJ, and;
D) a beam delivery unit comprising a beam path enclosure structure providing a laser output light pulse beam path, from a laser beam output port located on second laser unit to a remote laser beam output port at a terminus of said beam delivery unit;
E) a beam pointing means with feedback control for controlling the position and angle of said laser output light pulse beam at said remote laser beam output port;
F) a laser beam measurement means and control means for measuring pulse energy, wavelength and bandwidth of the laser light output pulses produced by said second laser unit and controlling the laser output light pulses with a feedback controller; and
G) a purge means for purging said beam path enclosure structure. - View Dependent Claims (51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65)
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66. A very narrow band two chamber high repetition rate gas discharge laser system for providing light in the form of laser output light pulses to a light receiving location comprising:
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A) a laser unit comprising;
1) a discharge chamber containing;
a) a laser gas and b) a pair of elongated spaced apart electrodes defining a discharge region where said laser gas is discharged, 2) a fan producing sufficient gas movement of said laser gas in said discharge region to clear from said discharge region, following each laser gas discharge, substantially all discharge produced ions prior to a next laser gas discharge when operating at a discharge rate in the range of 4,000 discharges per second or greater, 3) a first heat exchanger system removing at least 16 kw of heat energy from said first laser gas, 4) a line narrowing unit narrowing the spectral bandwidth of said first laser light output pulses produced in said first discharge chamber;
B) an electrical pulse power system providing electrical pulses to said pair of electrodes sufficient to produce said gas discharges in said discharge chamber at rates of about 4,000 gas discharges per second with precisely controlled pulse energies in excess of about 5 mJ;
C) a pulse stretcher for increasing laser output light pulse duration of said laser output light pulses produced in said discharge chamber;
D) a beam delivery unit comprising a beam path enclosure structure providing a laser output light beam path from said pulse stretcher to a laser output light beam output port at a terminus of said beam delivery unit, said beam delivery unit further comprising;
a beam pointing means with feedback control for controlling the position and angle of the beam of said laser output light pulses at said output port; and
E) a laser beam measurement means and control means for measuring pulse energy, wavelength and bandwidth of said laser output light pulses produced by said laser system and controlling said laser output light pulses with a feedback controller. - View Dependent Claims (67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78)
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79. A modular, narrow band, high repetition rate ultraviolet laser light source for providing light in the form of laser output light pulses to a light receiving location in a production line machine comprising:
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A) a laser unit comprising;
1) a discharge chamber containing;
a) a laser gas and b) a pair of elongated spaced apart electrodes defining a discharge region in which said laser gas is discharged, 2) a gas circulation means for producing sufficient gas movement of said laser gas in said discharge region to clear from said discharge region, following each laser gas discharge, substantially all discharge produced ions prior to a next laser gas discharge when operating at a laser output light pulse repetition rate in the range of 2,000 pulses per second or greater, 3) a heat exchanger system removing heat energy from said laser gas, so as to maintain the temperature of said laser gas within a desired range, and 4) an electrical pulse power system providing electrical pulses to said pair of electrodes sufficient to produce laser output light pulses at rates of about 2,000 pulses per second or greater;
B) a beam delivery unit comprising a beam path enclosure structure providing a laser output light pulse beam path, from a laser beam output port located on said laser unit to a remote laser beam output port at a terminus of said beam delivery unit;
C) a beam pointing means with feedback control for controlling the position and angle of said laser output light pulse beam at said remote laser beam output port;
D) a laser beam measurement means and control means measuring pulse energy, wavelength and bandwidth of the laser light output pulses produced by said laser unit and controlling the laser output light pulses with a feedback controller; and
E) a purge means for purging said beam path enclosure structure.
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80. A very narrow band two chamber high repetition rate gas discharge laser system for providing light in the form of laser output light pulses to a light receiving location comprising:
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A) a first laser unit comprising;
1) a first discharge chamber containing;
a) a first laser gas and b) a first pair of elongated spaced apart electrodes defining a first discharge region where said first laser gas is discharged, 2) a first fan producing sufficient gas movement of said first laser gas in said first discharge region to clear from said first discharge region, following each laser gas discharge, substantially all discharge produced ions prior to a next laser gas discharge when operating at a discharge rate in the range of 4,000 discharges per second or greater, 3) a first heat exchanger system removing heat energy from said first laser gas, 4) a line narrowing unit narrowing the spectral bandwidth of said first laser light output pulses produced in said first discharge chamber;
B) a second laser unit comprising;
1) a second discharge chamber comprising;
a) a second laser gas, b) a second pair of elongated spaced apart electrodes defining a second discharge region where said second laser gas is discharged, 2) a second fan producing sufficient gas movement of said second laser gas in said second discharge region to clear from said second discharge region, following each laser gas discharge, substantially all discharge produced ions prior to a next laser gas discharge when operating at a laser gas discharge rate in the range of 4,000 laser gas discharges per second or greater, 3) a second heat exchanger system removing heat energy from said second laser gas;
C) an electrical pulse power system providing electrical pulses to said first pair of electrodes and to said second pair of electrodes sufficient to produce said gas discharges in each of said first and second discharge chambers at rates at or above about 4,000 gas discharges per second with precisely controlled pulse energies;
D) a pulse stretcher for increasing laser output light pulse duration of said second laser output light pulses produced in said second discharge chamber;
E) relay optics directing said first laser output light pulses produced in said first discharge chamber through said second discharge chamber to produce amplified second laser output light pulses;
F) a beam delivery unit comprising a beam path enclosure structure providing a laser output light beam path from said pulse stretcher to a laser output light beam output port at a terminus of said beam delivery unit, said beam delivery unit further comprising;
a beam pointing means with feedback control for controlling the position and angle of the beam of said laser output light pulses at said output port at said terminus; and
G) a laser beam measurement means and control means for measuring pulse energy, wavelength and bandwidth of said laser output light pulses produced by said laser system and controlling said laser output light pulses with a feedback controller. feedback control for automatic control.
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Specification