Laser system

• US 7,643,529 B2
• Filed: 10/31/2007
• Issued: 01/05/2010
• Est. Priority Date: 11/01/2005
• Status: Active Grant

• Current Assignee: Cymer Incorporated (ASML Holding NV)
• Original Assignee: Cymer Incorporated (ASML Holding NV)
• Inventors: Sandstrom, Richard L., Brown, Daniel J. W., Partlo, William N.
• Primary Examiner(s): Nguyen; Dung T
• Application Number:
  US11/982,103
• Publication Number:
  US 20080225904A1
• Time in Patent Office: 797 Days
• Field of Search: 372/55, 372/69, 372/92
• US Class Current: 372/55
• CPC Class Codes: G03F 7/70025 by lasers
• CPC Class Codes: G03F 7/70041 by pulsed sources, e.g. multiplexing, pulse duration, interval control or intensity control
• CPC Class Codes: G03F 7/70341 Details of immersion lithography aspects, e.g. exposure media or control of immersion liquid supply chemical composition of immersion liquids G03F7/2041
• CPC Class Codes: G03F 7/7055 Exposure light control in all parts of the microlithographic apparatus, e.g. pulse length control or light interruption
• CPC Class Codes: H01S 2301/02 ASE (amplified spontaneous emission), noise; Reduction thereof
• CPC Class Codes: H01S 3/005 Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping shaping laser beam for working metal or other materials B23K26/06; optical elements, systems or apparatus in general G02B
• CPC Class Codes: H01S 3/0057 Temporal shaping, e.g. pulse compression, frequency chirping soliton generation and propagation G02F1/3513, H01S3/063 and H01S3/108
• CPC Class Codes: H01S 3/08004 incorporating a dispersive element, e.g. a prism for wavelength selection H01S3/0811, H01S3/08022 take precedence
• CPC Class Codes: H01S 3/08009 using a diffraction grating
• CPC Class Codes: H01S 3/083 Ring lasers fibre ring lasers H01S3/06791
• CPC Class Codes: H01S 3/10092 Coherent seed, e.g. injection locking
• CPC Class Codes: H01S 3/225 comprising an excimer or exciplex
• CPC Class Codes: H01S 3/2251 ArF, i.e. argon fluoride is comprised for lasing around 193 nm
• CPC Class Codes: H01S 3/2258 F2, i.e. molecular fluoride is comprised for lasing around 157 nm
• CPC Class Codes: H01S 3/2333 Double-pass amplifiers
• CPC Class Codes: H01S 3/2383 Parallel arrangements

Abstract

An apparatus/method may comprise a line narrowed pulsed lithography laser light source which may comprise: a seed pulse providing laser system which may comprise: a first pulsed seed laser producing seed pulses at a rate of X kHz; a second pulsed seed laser producing seed pulses at a rate of X kHz; an amplification system which may comprise: a first amplifier gain system which may comprise a first and a second pulsed gas discharge amplifier gain medium, each with a nominal center wavelength in the UV range, and each operating at ½ X kHz on output pulses from the first seed laser; a second amplifier gain system which may comprise a first and a second pulsed amplifier gain medium, each with a nominal center wavelength in the UV range, and each operating at ½ X kHz on output pulses from the second seed laser.

Claims

1. An apparatus comprising:

a narrow band pulsed lithography laser light source comprising;

a seed pulse providing laser system comprising;

a single pulsed solid state seed laser with a nominal center wavelength outside of the UV range and operating at 2X kHz;

an amplification system comprising;

a first amplifier gain system comprising a first and a second pulsed gas discharge amplifier gain medium, each with a nominal center wavelength in the UV range, and each operating at ½

X kHz on output pulses from the first seed laser system; and

a second amplifier gain system comprising a first and a second pulsed amplifier gain medium, each with a nominal center wavelength in the UV range, and each operating at ½

X kHz on alternating output pulses from the second seed laser system;

a seed pulse divider providing pulses from the solid state seed laser to a first amplifier gain system pulse divider and to a second amplifier gain system pulse divider, the first amplifier gain system pulse divider providing pulses to the first and second pulsed amplifier gain mediums of the first amplifier gain system and the second amplifier gain system pulse divider providing pulses to the first and second amplifier gain mediums of the second amplifier gain system; and

a pulse combiner combining the output pulses from the first and second amplifier gain systems to produce a light source output laser light pulse beam at a pulse repetition rate of 2X kHz.

2. The apparatus of claim 1 further comprising:

a frequency converter converting the wavelength of the output of the seed laser to a UV wavelength suitable for amplification in the amplifier gain mediums.

3. The apparatus of claim 2 further comprising:

each pulsed amplifier gain medium comprising a gas discharge laser system.

4. The apparatus of claim 3 further comprising:

X kHz is at least 4 kHz.

5. The apparatus of claim 4 further comprising:

each respective amplifier gain medium comprising a ring power amplification stage.

6. An apparatus comprising:

a narrow band pulsed solid state seed laser operating at an output repetition rate;

a seed pulse divider that receives an output from the narrow band pulsed solid state seed laser and produces alternating output pulses;

an amplification system comprising a plurality of pulsed gas discharge amplifier gain systems each operating at repetition rate that is a fraction of the output repetition rate and each supplied with alternating output pulses from the seed pulse divider; and

a pulse combiner combining the output pulses from the plurality of pulsed gas discharge amplifier gain systems to produce an output laser light pulse beam having pulses firing at interleaving times and at the output repetition rate.

7. The apparatus of claim 6, wherein each pulsed gas discharge amplifier gain system comprises a ring power amplification stage.

8. The apparatus of claim 6, wherein the output laser light pulse beam has a wavelength of about 193 nm.

9. The apparatus of claim 6, wherein the alternating output pulses received at the amplification system have a wavelength of about 193 nm.

10. The apparatus of claim 6, further comprising a frequency converter converting the wavelength of the output of the seed laser to a wavelength suitable for amplification in the pulsed gas discharge amplifier gain systems.

11. An apparatus comprising:

a narrow band pulsed solid state seed laser operating at an output repetition rate;

a seed pulse divider that receives an output from the narrow band pulsed solid state seed laser and produces output pulses;

an amplification system comprising a plurality of pulsed gas discharge amplifier gain systems each operating at repetition rate that is a fraction of the output repetition rate and each supplied with output pulses from the seed pulse divider; and

a pulse combiner combining the output pulses from the plurality of amplifier gain systems to produce an output laser light pulse beam having pulses firing at the output repetition rate and having a wavelength of 193 nm.

12. The apparatus of claim 11, wherein each pulsed gas discharge amplifier gain system comprises a ring power amplification stage.

13. The apparatus of claim 11, further comprising a frequency converter converting the wavelength of the output of the seed laser to a wavelength suitable for amplification in the pulsed gas discharge amplifier gain systems.

14. An apparatus comprising:

a narrow band pulsed solid state seed laser operating at an output repetition rate;

a seed pulse divider that receives an output from the narrow band pulsed solid state seed laser and produces alternating output pulses;

an amplification system comprising a plurality of pulsed gas discharge amplifier gain systems each comprising a ring power amplification stage operating at repetition rate that is a fraction of the output repetition rate and each supplied with output pulses from the seed pulse divider; and

a pulse combiner combining the output pulses from the plurality of pulsed gas discharge amplifier gain systems to produce an output laser light pulse beam having pulses firing at interleaving times and at the output repetition rate.

15. The apparatus of claim 14, further comprising a frequency converter converting the wavelength of the output of the seed laser to a wavelength suitable for amplification in the pulsed gas discharge amplifier gain systems.