Excimer laser and line narrowing module

Abstract

An excimer laser and a line-narrowing module capable of increasing and maximizing production yield in semiconductor manufacturing are disclosed. The line-narrowing module utilizes a beam expander that passes laser light, produced by and incident from a generator of the excimer laser and collimates the laser light in one direction. A diffraction grating receives the collimated laser light and diffracts the laser light and causes a traveling direction of the laser light to be separated according to an associated wavelength of the laser light. A multi-wavelength reflector located at a reflecting position on one side between the diffraction grating and the beam expander in order to re-enter the laser light having a multi-wavelength into the generator through the beam expander. The multi-wavelength reflector reflects the laser light consisting of a plurality of wavelengths among the laser light whose traveling direction is separated from the diffraction grating onto the beam expander.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an excimer laser according to an exemplary embodiment of the present invention;

FIGS. 2 and 3 are diagrams illustrating the generator of FIG. 1;

FIG. 4 is a graph plotting change of output energy according to a change of concentration of fluorine supplied into the laser chamber of FIG. 2;

FIG. 5 is a graph plotting change of output energy according to change of the pressure of a mixture gas supplied into the laser chamber of FIG. 2;

FIG. 6 is a detailed diagram illustrating the line-narrowing module of FIG. 1;

FIG. 7 is sectional view illustrating the reflection diffraction grating of FIG. 6; and

FIG. 8 is a schematic diagram illustrating an exposure apparatus to which an excimer laser according to an exemplary embodiment of the present invention is employed.

Claims

1. A line-narrowing module of an excimer laser, comprising: a beam expander disposed on a first side of an excimer laser light generator, said beam expander configured to pass laser light produced by and incident from said generator and collimating said laser light in one direction;a diffraction grating disposed on a second side of said generator, said first side opposite from said second side, said grating configured to diffract the collimated laser light received from said beam expander such that a traveling direction of said laser light is separated according to a respective wavelength associated with said laser light; anda multi-wavelength reflector disposed at a reflecting position between said diffraction grating and said beam expander, said multi-wavelength reflector configured to reflect said multi-wavelength laser light separated by said diffraction grating back to said generator through said beam expander.

2. The line-narrowing module according to claim 1, wherein the multi-wavelength laser light includes laser light having a different plurality of single wavelengths.

3. The line-narrowing module according to claim 1, wherein the multi-wavelength reflector comprises: a mirror for reflecting said multi-wavelength laser light onto said beam expander; anda vibrator for vibrating one side of said mirror in order to collect the laser light having a plurality of single wavelengths and different traveling directions varied by said mirror.

4. The line-narrowing module according to claim 3, wherein said vibrator comprises a piezo actuator.

5. The line-narrowing module according to claim 3, wherein said vibrator vibrates one side of said mirror at a frequency higher than an oscillating frequency supplied to said generator of said excimer laser.

6. The line-narrowing module according to claim 1, further comprising a first slit formed on one side of said beam expander provided with a first aperture defining a cross section of the laser light when the laser light incident from said generator to said beam expander passes through said first aperture.

7. The line-narrowing module according to claim 1, wherein said beam expander reduces a cross section associated with said multi-wavelength laser light reflected and incident from said multi-wavelength reflector such that an optical path of said multi-wavelength laser light is varied

8. The line-narrowing module according to claim 1, wherein said diffraction grating comprises an Echelete grating.

9. The line-narrowing module according to claim 1, wherein said diffraction grating comprises a Littrow grating.

10. An excimer laser comprising: a generator exciting a light emitting material to produce laser light;a line-narrowing module positioned on a first side of said generator, said line-narrowing module comprising: a beam expander passing said laser light produced by and incident from said generator, said beam expander collimating said laser light in one direction;a diffraction grating configured to receive said laser light collimated through said beam expander, said grating diffracting said laser light such that a traveling direction of said laser light is separated according to a wavelength associated with said laser light; anda multi-wavelength reflector disposed between said diffraction grating and said beam expander toward a first side of said line-narrowing module, said multi-wavelength reflector reflecting said laser light having at least a different plurality of single wavelengths from the laser light whose traveling direction is separated by said diffraction grating onto said beam expander such that said laser light having a multi-wavelength re-enters said generator through said beam expander; andan output coupler module 30 positioned on a second side of said generator opposite from said first, said coupler emitting said laser light re-entered into said generator externally from said laser.

11. The excimer laser according to claim 10, wherein said generator comprises: a laser chamber filled with a light emitting material;a voltage supply configured outside of said laser chamber, said voltage supply for providing supply voltage having a predetermined oscillating frequency;a plurality of main electrodes disposed a predetermined distance apart and located at an upper end and a lower end of said laser chamber, said electrodes receiving supply voltage from said voltage supply and electrifying said light emitting material inside said laser chamber;a fan formed within said chamber to circulate said light emitting material between said main electrodes at a constant flow rate;a heat exchanger positioned below said fan for absorbing and cooling heat associated with said light emitting material;a storage capacitor formed on a cable connected from said voltage supply to any one of said main electrodes;a plurality of arc pins disposed around said main electrodes and along said cable, said arc pins discharging electricity induced in the proximity of said main electrodes in order to preliminarily ionize ultraviolet light from said light emitting material; andpeaking capacitors disposed between said arc pins and said storage capacitor, said peaking capacitors amplifying said supply voltage being charged or discharged by said storage capacitor.

12. The excimer laser according to claim 11, wherein said laser chamber comprises: a first window formed on a first sidewall of said laser chamber for providing laser light, produced between said main electrodes by said light emitting material, to be incident onto said line-narrowing module; anda second window formed on a second sidewall of said laser chamber for providing laser light to be incident onto said output coupler module.

13. The excimer laser according to claim 12, wherein said first window passes all of the laser light having various wavelengths produced in said laser chamber through to said line-narrowing module; andsaid second window reflects various wavelengths of all the laser light produced in said laser chamber onto said first window and selectively passes only laser light having the different plurality of single wavelengths split and extracted by said line-narrowing module.

14. The excimer laser according to claim 11, wherein said voltage supply comprising: a pulse transformer for transforming primary high voltage into secondary high voltage having a predetermined frequency; anda switch for switching the high voltages at the predetermined oscillating frequency so that the laser light is repetitively emitted from said light emitting material flowing between said main electrodes while the predetermined frequency of the secondary high voltage produced by said pulse transformer is charged or discharged in or from said storage capacitor.

15. The excimer laser according to claim 10, wherein said multi-wavelength reflector comprises: a mirror for reflecting the multi-wavelength laser light onto said beam expander; anda vibrator for vibrating one side of said mirror in order to collect the laser light having a plurality of single wavelengths and different traveling directions varied by said mirror.

16. The excimer laser according to claim 15, wherein said vibrator comprises a piezo actuator.

17. The excimer laser according to claim 15, wherein said vibrator vibrates one side of said mirror at a frequency higher than an oscillating frequency supplied to said generator of said excimer laser.

18. The excimer laser according to claim 10, wherein said line-narrowing module comprises a first slit formed on one side of said beam expander and a first aperture associated with said first slit defining a cross section of the laser light when the laser light incident from said generator to said beam expander passes therethrough.

19. The excimer laser according to claim 10, wherein said beam expander reduces a cross section of said multi-wavelength laser light reflected and incident from said multi-wavelength reflector, and varies an optical path associated with said multi-wavelength laser light.

20. The excimer laser according to claim 10, wherein the output coupler module includes a second slit that is formed with a second aperture defining a cross section of the laser light having the different plurality of single wavelengths, said second slit allowing said laser light having the different plurality of single wavelengths emitted through said generator from said line narrowing module to pass therethrough.

21. The excimer laser according to claim 19, wherein said output coupler module further comprises: a wavelength detector for detecting said laser light having the different plurality of single wavelengths that passes through said second aperture; anda wavelength controller for feeding back a detected signal detected by said wavelength detector to said line-narrowing module to allow said laser light having a corresponding one of the different plurality of single wavelengths to be selected by said line-narrowing module based on said detected signal.