Beam homogenizer and laser irradiation apparatus and method of manufacturing semiconductor device

• US 20040058553A1
• Filed: 09/22/2003
• Published: 03/25/2004
• Est. Priority Date: 09/19/2002
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Tanaka, Koichiro
• Granted Patent: US 7,594,965 B2
• Time in Patent Office: Days
• US Class Current: 438/710
• CPC Class Codes: B23K 26/064 by means of optical elements, e.g. lenses, mirrors or prisms
• CPC Class Codes: B23K 26/0648 comprising lenses
• CPC Class Codes: B23K 26/0732 into a rectangular shape
• CPC Class Codes: B23K 26/0738 into a linear shape
• CPC Class Codes: G02B 27/09 Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for adapting the beam shape of a laser diode G02B19/0052; adapting the beam shape of an LED G02B19/0061; coupling into light guides using intermediate optical elements G02B6/4204; beam shaping specially adapted for lasers H01S3/005
• CPC Class Codes: G02B 27/0927 Systems for changing the beam intensity distribution, e.g. Gaussian to top-hat
• CPC Class Codes: G02B 27/0994 Fibers, light pipes optical fibers per se G02B6/02
• CPC Class Codes: Y10T 117/1008 with responsive control means

Abstract

The inhomogeneous energy distribution at the beam spot on the irradiated surface is caused by a structural problem and processing accuracy of the cylindrical lens array forming an optical system.

According to the present invention, in the optical system for forming a rectangular beam spot, an optical system for homogenizing the energy distribution of the shorter side direction of a rectangular beam spot of a laser light on an irradiated surface is replaced with a light guide. The light guide is a circuit that can confine emitted beams in a certain region and guide and transmit its energy flow in parallel with the axis of a path thereof.

Claims

1. A beam homogenizer for shaping a beam spot of a laser light on an irradiated surface into a line-shape, comprising a light guide for homogenizing an energy distribution of the laser light along a width direction of the line-shape on the irradiated surface.

2. The beam homogenizer according to claim 1, wherein said light guide comprises two reflective surfaces facing to each other.

3. A beam homogenizer for shaping a beam spot of a laser light on an irradiated surface into a line-shape, comprising a light pipe for homogenizing an energy distribution of the laser light along a width direction of the line-shape on the irradiated surface.

4. The beam homogenizer according to claim 3, wherein said light pipe comprises two reflective surfaces facing to each other.

5. A beam homogenizer for shaping a beam spot of a laser light on an irradiated surface into a line-shape, comprising:

a light guide for homogenizing an energy distribution of the laser light along a width direction of the line-shape on the irradiated surface; and

at least one cylindrical lens for condensing light output from said light guide along a width direction of the line-shape on the irradiated surface.

6. The beam homogenizer according to claim 5, wherein said light guide comprises two reflective surfaces facing to each other.

7. A beam homogenizer for shaping a beam spot of a laser light on an irradiated surface into a line-shape, comprising:

a light pipe for homogenizing an energy distribution of the laser light along a width direction of the line-shape on the irradiated surface; and

at least one cylindrical lens for condensing light output from said light pipe along a width direction of the line-shape on the irradiated surface.

8. The beam homogenizer according to claim 7, wherein said light pipe comprises two reflective surfaces facing to each other.

9. A beam homogenizer for shaping a beam spot of a laser light on an irradiated surface into a line-shape, comprising:

a unit for homogenizing an energy distribution of the laser light along a length direction of the line-shape on the irradiated surface; and

a light guide for homogenizing the energy distribution along a width direction of the line-shape on the irradiated surface,

wherein said unit has at least a cylindrical lens array.

10. The beam homogenizer according to claim 9, wherein said light guide comprises two reflective surfaces facing to each other.

11. A beam homogenizer for shaping a beam spot of a laser light on an irradiated surface into a line-shape, comprising:

a unit for homogenizing an energy distribution of the laser light along a length direction of the line-shape on the irradiated surface; and

a light pipe for homogenizing the energy distribution along a width direction of the line-shape on the irradiated surface,

wherein said unit has at least a cylindrical lens array.

12. The beam homogenizer according to claim 11, wherein said light pipe comprises two reflective surfaces facing to each other.

13. A laser irradiation apparatus for shaping a beam spot of a laser light on an irradiated surface into a line-shape, comprising:

a laser oscillator; and

a beam homogenizer,

wherein said beam homogenizer has a light guide for homogenizing an energy distribution of the laser light along a width direction of the line-shape.

14. The laser irradiation apparatus according to claim 13, wherein said laser oscillator is an excimer laser, a YAG laser, or a glass laser.

15. The laser irradiation apparatus according to claim 13, wherein said laser oscillator is a YVO₄ laser, a YLF laser, or an Ar laser.

16. A laser irradiation apparatus for shaping a beam spot of a laser light on an irradiated surface into a line-shape, comprising:

a laser oscillator;

a beam homogenizer,

wherein said beam homogenizer has a light guide for homogenizing an energy distribution of the laser light along a width direction of the line-shape, and

said light guide comprises two reflective surfaces facing to each other.

17. The laser irradiation apparatus according to claim 16, wherein said laser oscillator is an excimer laser, a YAG laser, or a glass laser.

18. The laser irradiation apparatus according to claim 16, wherein said laser oscillator is a YVO₄ laser, a YLF laser, or an Ar laser.

19. A laser irradiation apparatus for shaping a beam spot of a laser light on an irradiated surface into a line-shape, comprising:

a laser oscillator; and

a beam homogenizer,

wherein said beam homogenizer has a light pipe for homogenizing an energy distribution of the laser light along a width direction of the line-shape.

20. The laser irradiation apparatus according to claim 19, wherein said laser oscillator is an excimer laser, a YAG laser, or a glass laser.

21. The laser irradiation apparatus according to claim 19, wherein said laser oscillator is a YVO₄ laser, a YLF laser, or an Ar laser.

22. A laser irradiation apparatus for shaping a beam spot of a laser light on an irradiated surface into a line-shape, comprising:

a laser oscillator; and

a beam homogenizer,

wherein said beam homogenizer has a light pipe for homogenizing an energy distribution of the laser light along a width direction of the line-shape, and

said light pipe comprises two reflective surfaces facing to each other.

23. The laser irradiation apparatus according to claim 22, wherein said laser oscillator is an excimer laser, a YAG laser, or a glass laser.

24. The laser irradiation apparatus according to claim 22, wherein said laser oscillator is a YV0₄ laser, a YLF laser, or an Ar laser.

25. A method of manufacturing a semiconductor device, comprising the steps of:

forming a non-single-crystal semiconductor film on a substrate;

generating a laser beam with a laser beam oscillator;

using at least a cylindrical lens array and a light guide to shape the laser beam so as to form a linear beam spot of a laser light on an irradiated surface with its energy distribution homogenized;

setting the substrate with the non-single-crystal semiconductor film formed thereon on a stage to make a surface of the non-single-crystal semiconductor film coincide with the irradiated surface; and

performing a laser annealing of the non-single-crystal semiconductor film by irradiating the semiconductor film surface with the linear laser beam while causing said stage to scan relative to the laser beam,

wherein said cylindrical lens array acts on the linear beam spot along a length direction of the spot, and

said light guide acts on the linear beam spot along a width direction of the spot.

26. The method of manufacturing a semiconductor device according to claim 25, wherein said laser beam oscillator is an excimer laser, a YAG laser, or a glass laser.

27. The method of manufacturing a semiconductor device according to claim 25, wherein said laser beam oscillator is a YVO₄, a YLF laser, or an Ar laser.

28. A method of manufacturing a semiconductor device, comprising the steps of:

forming a non-single-crystal semiconductor film on a substrate;

generating a laser beam with a laser beam oscillator;

using at least a cylindrical lens array and a light guide to shape the laser beam so as to form a linear beam spot of a laser light on an irradiated surface with its energy distribution homogenized;

setting the substrate with the non-single-crystal semiconductor film formed thereon on a stage to make a surface of the non-single-crystal semiconductor film coincide with the irradiated surface; and

performing a laser annealing of the non-single-crystal semiconductor film by irradiating the semiconductor film surface with the linear laser beam while causing said stage to scan relative to the laser beam,

wherein said cylindrical lens array acts on the linear beam spot along a length direction of the spot,

said light guide acts on the linear beam spot along a width direction of the spot, and

said light guide comprises two reflective surfaces facing to each other.

29. The method of manufacturing a semiconductor device according to claim 28, wherein said laser beam oscillator is an excimer laser, a YAG laser, or a glass laser.

30. The method of manufacturing a semiconductor device according to claim 28, wherein said laser beam oscillator is a YV0₄, a YLF laser, or an Ar laser.

31. A method of manufacturing a semiconductor device, comprising the steps of:

forming a non-single-crystal semiconductor film on a substrate;

generating a laser beam with a laser beam oscillator;

using at least a cylindrical lens array and a light pipe to shape the laser beam so as to form a linear beam spot of a laser light on an irradiated surface with its energy distribution homogenized;

setting the substrate with the non-single-crystal semiconductor film formed thereon on a stage to make a surface of the non-single-crystal semiconductor film coincide with the irradiated surface; and

performing a laser annealing of the non-single-crystal semiconductor film by irradiating the semiconductor film surface with the linear laser beam while causing said stage to scan relative to the laser beam,

wherein said cylindrical lens array acts on the linear beam spot along a length direction of the spot, and

said light pipe acts on the linear beam spot along a width direction of the spot.

32. The method of manufacturing a semiconductor device according to claim 31, wherein said laser beam oscillator is an excimer laser, a YAG laser, or a glass laser.

33. The method of manufacturing a semiconductor device according to claim 31, wherein said laser beam oscillator is a YVO₄, a YLF laser, or an Ar laser.

34. A method of manufacturing a semiconductor device, comprising the steps of:

forming a non-single-crystal semiconductor film on a substrate;

generating a laser beam with a laser beam oscillator;

using at least a cylindrical lens array and a light pipe to shape the laser beam so as to form a linear beam spot of a laser light on an irradiated surface with its energy distribution homogenized;

setting the substrate with the non-single-crystal semiconductor film formed thereon on a stage to make a surface of the non-single-crystal semiconductor film coincide with the irradiated surface; and

performing a laser annealing of the non-single-crystal semiconductor film by irradiating the semiconductor film surface with the linear laser beam while causing said stage to scan relative to the laser beam,

wherein said cylindrical lens array acts on the linear beam spot along a length direction of the spot,

said light pipe acts on the linear beam spot along a width direction of the spot, and

said light pipe comprises two reflective surfaces facing to each other.

35. The method of manufacturing a semiconductor device according to claim 34, wherein said laser beam oscillator is an excimer laser, a YAG laser, or a glass laser.

36. The method of manufacturing a semiconductor device according to claim 34, wherein said laser beam oscillator is a YVO₄, a YLF laser, or an Ar laser.

37. A method of manufacturing a semiconductor device comprising:

providing a laser light;

passing said laser light through a light guide; and

irradiating a semiconductor film with said laser light after passing through said light guide to crystallize said semiconductor film,

wherein an energy distribution of the laser light at a surface of said semiconductor film is homogenized by said light guide.

38. The method of manufacturing a semiconductor device according to claim 37, wherein said light guide comprises two reflective surfaces facing to each other.

39. A method of manufacturing a semiconductor device comprising:

providing a laser light;

passing said laser light through a light pipe; and

irradiating a semiconductor film with said laser light after passing through said light pipe to crystallize said semiconductor film,

wherein an energy distribution of the laser light at a surface of said semiconductor film is homogenized by said light pipe.

40. The method of manufacturing a semiconductor device according to claim 39, wherein said light pipe comprises two reflective surfaces facing to each other.

41. A method of manufacturing a semiconductor device comprising:

providing a laser light having a cross section perpendicular to a propagation direction of said laser light wherein said cross section has a length and a width;

increasing only the length of the cross section of the laser light;

passing said light through a light guide; and

irradiating a semiconductor film with said light after passing through said light guide to crystallize said semiconductor film,

wherein an energy distribution of the laser light along a width direction of said cross section is homogenized by said light guide.

42. A method according to claim 41, wherein the length of the cross section of the laser light is increased by using a cylindrical lens array having a plurality of cylindrical lenses.

43. The method of manufacturing a semiconductor device according to claim 41, wherein said light guide comprises two reflective surfaces facing to each other.

44. A method of manufacturing a semiconductor device comprising:

providing a laser light having a cross section perpendicular to a propagation direction of said laser light wherein said cross section has a length and a width;

increasing only the length of the cross section of the laser light;

passing said light through a light pipe; and

irradiating a semiconductor film with said light after passing through said light pipe to crystallize said semiconductor film,

wherein an energy distribution of the laser light along a width direction of said cross section is homogenized by said light pipe.

45. A method according to claim 44, wherein the length of the cross section of the laser light is increased by using a cylindrical lens array having a plurality of cylindrical lenses.

46. The method of manufacturing a semiconductor device according to claim 44, wherein said light pipe comprises two reflective surfaces facing to each other.