Diode-pumped solid-state laser device for laser annealing

Abstract

A laser annealing apparatus is provided that includes a plurality of triple frequency solid state lasers, each outputting a radiation beam having a wavelength between 340 nm and 360 nm. The beam figure of merit (M2) of each output beam is greater than 50 on one lateral axis and greater than 20 on the other lateral axis. The output beams are combined and form a wire harness that is projected onto the substrate being annealed. Each output beam contributes to the length of the wire beam.

Claims

1. Solid-state laser devices, include: a gain element in the form of a slab excited by the pump radiation to provide a gain volume in the gain element; The first nonlinear crystal; A second nonlinear crystal; two resonator mirrors, the two resonator mirrors are reflective to fundamental wave radiation, the gain element, the first nonlinear crystal, and the second nonlinear crystal are located in a resonator formed between the two resonator mirrors, the excited gain element generates a repetitive pulsed fundamental wave radiation beam, the repetitive pulsed fundamental wave radiation beam circulates in the resonator, the fundamental wave radiation beam has a first transverse axis and a second transverse axis that are orthogonal to each other; wherein (i) the cross-sectional dimensions of the gain volume, (ii) the resonator length between the two resonator mirrors, and (iii) the optical powers of the two resonator mirrors are selected to achieve a beam quality factor M of the fundamental radiation beam 2 (a) greater than 50 on the first horizontal axis and (b) greater than 10 on the second horizontal axis; wherein the first nonlinear crystal converts a portion of the fundamental radiation beam into a second harmonic radiation beam by second harmonic generation, leaving a residual fundamental radiation beam, and the second nonlinear crystal generates a third harmonic radiation beam from the residual fundamental radiation beam and the second harmonic radiation beam by sum frequency mixing; and wherein the propagation distance in the first nonlinear crystal is selected to achieve a beam quality factor M of the second harmonic radiation beam in the first transverse axis and the second transverse axis 2 Greater than the beam quality factor M corresponding to the fundamental radiation beam 2 , and another propagation distance in the second nonlinear crystal is selected to achieve a beam quality factor M of the third harmonic radiation beam in the first transverse axis and the second transverse axis 2 Greater than the beam quality factor M corresponding to the second harmonic radiation beam 2 . 2 . The solid-state laser device of claim 1 , further comprising an output mirror that directs the third harmonic radiation beam out of the resonator.

3. The solid-state laser device according to claim 2, in, The reflectivity of the output mirror and the pulse repetition frequency are selected to produce a pulse energy of the third harmonic radiation beam greater than 100 millijoules.

4. The solid-state laser device according to claim 1, wherein the third harmonic radiation has a full width at half maximum pulse with a duration greater than 10 nanoseconds.

5. The solid-state laser device according to claim 1, further comprising a Pockels cell and a quarter wave plate, the Pockels cell and the quarter wave plate being located in the resonator and cooperatively arranged for Q-switching operation.

6. The solid-state laser device according to claim 1, in, The gain elements are excited by pump radiation provided by one or more diode laser arrays.

7. The solid-state laser device according to claim 1, in, The gain element is made of neodymium-doped yttrium aluminum garnet (Nd 3+ Doped YAG) crystal.

8. The solid-state laser device according to claim 1, in, The first nonlinear crystal is made of lithium triborate (LBO).

9. The solid-state laser device according to claim 1, in, The first nonlinear crystal is arranged for type 1 frequency doubling of the fundamental radiation beam.

10. The solid-state laser device according to claim 1, in, The second nonlinear crystal is made of lithium triborate (LBO), beta barium borate (BBO), cesium borate (CB) or cesium lithium borate (CLBO).

11. The solid-state laser device according to claim 1, in, The second nonlinear crystal is arranged for type 1 sum frequency mixing of the residual fundamental radiation beam with the second harmonic radiation beam.

12. The solid-state laser device according to claim 1, in, The beam quality factor M of the second harmonic radiation beam on the first horizontal axis 2 is the beam quality factor M of the fundamental radiation beam on the first transverse axis 2 at least twice as much.

13. The solid-state laser device according to claim 1, in, The beam quality factor M of the third harmonic radiation beam on the first horizontal axis 2 is the beam quality factor M of the second harmonic radiation beam on the first horizontal axis 2 1.5 times of.

14. The solid-state laser device according to claim 1, in, The beam quality factor M of the third harmonic radiation beam on the first horizontal axis 2 is the beam quality factor M of the residual fundamental radiation beam on the first horizontal axis 2 1.5 times of.

15. The solid-state laser device according to claim 1, in, The beam quality factor M of the third harmonic radiation beam 2 Greater than 200 on the first horizontal axis.

16. The solid-state laser device according to claim 1, in, The gain element has a first cross-sectional dimension on the first transverse axis and a second cross-sectional dimension on the second transverse axis, the first cross-sectional dimension being greater than or equal to three times the second cross-sectional dimension.

17. The solid-state laser device according to claim 1, in, The third harmonic radiation beam has a wavelength in the range from 340 nanometers to 360 nanometers.

18. An optical device for annealing a layer on a substrate, comprising a line projector and a plurality of solid-state laser devices according to claim 1, wherein the line projector is arranged to receive the third harmonic radiation beam therefrom, form the third harmonic radiation beam into a line beam, and project the line beam onto the layer.

19. The optical device according to claim 18, in, Each third harmonic radiation beam contributes to the entire length of the beam.

20. The optical device according to claim 18, in, The layer is made of silicon.

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