Laser irradiation method and laser irradiation apparatus

Patent metadata

Field	Value
Publication number	US-9296068-B2
Application number	US-89998310-A
Country	US
Kind code	B2
Filing date	Oct 7, 2010
Priority date	Mar 26, 2004
Publication date	Mar 29, 2016
Grant date	Mar 29, 2016

Abstract

An object of the present invention is to provide a laser irradiation method and a laser irradiation apparatus for irradiating an irradiation surface with a linear beam having more homogeneous intensity by blocking a low-intensity part of the linear beam without forming the fringes due to the diffraction on the irradiation surface. In the laser irradiation, a laser beam emitted from a laser oscillator 101 passes through a slit 102 so as to block a low-intensity part of the laser beam, the traveling direction of the laser beam is bent by a mirror 103 , and an image formed at the slit is projected to an irradiation surface 106 by a convex cylindrical lens 104.

First claim

What is claimed is:

1. A laser irradiation method comprising:
blocking a low-intensity part of a first laser beam emitted from a laser oscillator which is either a YAG laser or a YVO 4 laser to form a second laser beam, by making the first laser beam pass through a slit;
bending a traveling direction of the second laser beam by a predetermined angle by a mirror; and
projecting an image formed at the slit to an irradiation surface by a convex cylindrical lens,
wherein the second laser beam is shaped into a linear beam on the irradiation surface,
wherein the slit, the convex cylindrical lens, and the irradiation surface are arranged so that a distance (M1) between the slit and the convex cylindrical lens and a distance (M2) between the convex cylindrical lens and the irradiation surface satisfy following equations 1 and 2:
M 1= f ( s+D )/ D   [Equation 1]

M 2= f ( s+D )/ s   [Equation 2]

where s is a width of the slit, D is a length of the linear beam in a long-side direction, and f is a focal length of the convex cylindrical lens,
wherein the mirror is provided between the slit and the convex cylindrical lens,
wherein the convex cylindrical lens acts in the long-side direction of the linear beam, and
wherein the slit acts in the long-side direction of the linear beam.

2. The laser irradiation method according to claim 1 ,
wherein a second convex cylindrical lens is provided between the convex cylindrical lens and the irradiation surface in such a way that the second convex cylindrical lens is rotated by 90° from the convex cylindrical lens.

3. A laser irradiation apparatus comprising:
a laser oscillator which is either a YAG laser or a YVO 4 laser;
a slit for blocking a low-intensity part of a first laser beam emitted from the laser oscillator to form a second laser beam;
a mirror for bending a traveling direction of the second laser beam by a predetermined angle; and
a convex cylindrical lens for projecting to an irradiation surface an image formed at the slit in which the low-intensity part is blocked,
wherein the second laser beam is shaped into a linear beam on the irradiation surface,
wherein the slit, the convex cylindrical lens, and the irradiation surface are arranged so that a distance (M1) between the slit and the convex cylindrical lens and a distance (M2) between the convex cylindrical lens and the irradiation surface satisfy following equations 1 and 2:
M 1= f ( s+D )/ D   [Equation 1]

M 2= f ( s+D )/ s   [Equation 2]

where s is a width of the slit, D is a length of the linear beam in a long-side direction, and f is a focal length of the convex cylindrical lens,
wherein the mirror is provided between the slit and the convex cylindrical lens,
wherein the convex cylindrical lens acts in the long-side direction of the linear beam, and
wherein the slit acts in the long-side direction of the linear beam.

4. The laser irradiation apparatus according to claim 3 , wherein a second convex cylindrical lens is provided between the convex cylindrical lens and the irradiation surface in such a way that the second convex cylindrical lens is rotated by 90° from the convex cylindrical lens.

5. A laser irradiation method comprising:
blocking a low-intensity part of a first laser beam emitted from a laser oscillator which is either a YAG laser or a YVO 4 laser to form a second laser beam, by making the first laser beam pass through a slit;
bending a traveling direction of the second laser beam by a predetermined angle by a mirror; and
projecting an image formed at the slit to an irradiation surface by a convex spherical lens,
wherein the second laser beam is shaped into a linear beam on the irradiation surface,
wherein the slit, the convex spherical lens, and the irradiation surface are arranged so that a distance (M1) between the slit and the convex spherical lens and a distance (M2) between the convex spherical lens and the irradiation surface satisfy following equations 1 and 2:
M 1= f ( s+D )/ D   [Equation 1]

M 2= f ( s+D )/ s   [Equation 2]

where s is a width of the slit, D is a length of the linear beam in a long-side direction, and f is a focal length of the convex spherical lens,
wherein the mirror is provided between the slit and the convex spherical lens,
wherein the convex spherical lens acts in the long-side direction of the linear beam, and
wherein the slit acts in the long-side direction of the linear beam.

Assignees

• Tanaka Koichiro
• Yamamoto Yoshiaki
• Semiconductor Energy Lab

Inventors

• Tanaka Koichiro
• Yamamoto Yoshiaki

Classifications

• B23K26/0738

  into a linear shape · CPC title

• B23K26/066 Primary

  by using masks · CPC title

• H10D86/0229

  characterised by control of the annealing or irradiation parameters · CPC title

• B23K26/0656 Primary

  Operations & Transport · mapped topic

• H01L27/1285

  Electricity · mapped topic