Laser annealing method and laser annealing device

• US 8,569,814 B2
• Filed: 08/31/2011
• Issued: 10/29/2013
• Est. Priority Date: 01/13/2006
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Nishida, Kenichiro, Kawakami, Ryusuke, Kawaguchi, Norihito, Masaki, Miyuki
• Primary Examiner(s): Nhu, David
• Application Number:
  US13/222,427
• Publication Number:
  US 20120057613A1
• Time in Patent Office: 790 Days
• Field of Search: 257/72, 257/293, 257/294, 257/428, 257/431, 257/432, 257/E21.17, 257/E21.134, 257/E21.347, 257/E21.475
• US Class Current: 257/294
• CPC Class Codes: B23K 26/0608 in the same heat affected zone [HAZ] B23K26/0613, B23K26/0619 take precedence
• CPC Class Codes: B23K 26/067 Dividing the beam into multiple beams, e.g. multifocusing
• CPC Class Codes: B23K 26/0732 into a rectangular shape
• CPC Class Codes: B23K 26/0738 into a linear shape
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02678 Beam shaping, e.g. using a mask
• CPC Class Codes: H01L 21/02691 Scanning of a beam
• CPC Class Codes: H01L 21/268 using electromagnetic radiation, e.g. laser radiation
• CPC Class Codes: H01L 27/1285 using control of the annealing or irradiation parameters, e.g. using different scanning direction or intensity for different transistors

Abstract

The energy distribution in the short-side direction of a rectangular laser beam applied to an amorphous semiconductor film (amorphous silicon film) is uniformized. It is possible to the energy distribution in the short-side direction of the rectangular laser beam by the use of a cylindrical lens array or a light guide and concentrating optical systems or by the use of an optical system including a diffracting optical element. Accordingly, since the effective energy range of a laser beam applied to the amorphous semiconductor film is widened and the transport speed of a substrate can be enhanced as much, it is possible to improve the processing ability of the laser annealing.

Claims

1. A laser irradiation device comprising:

a first cylindrical lens;

a second cylindrical lens;

an optical system interposed between the first cylindrical lens and the second cylindrical lens, the optical system including a first glass plate and a second glass plate,

wherein the first glass plate and the second glass plate are adjacent to each other, and

wherein a first length of the first glass plate is different from a second length of the second glass plate.

2. The laser irradiation device according to claim 1, further comprising:

a light guide provided so that a laser beam passing through the light guide enters the first cylindrical lens.

3. The laser irradiation device according to claim 1, further comprising:

a cylindrical lens array between the first cylindrical lens and the second cylindrical lens.

4. The laser irradiation device according to claim 1, further comprising:

a second optical system between the first cylindrical lens and the second cylindrical lens, the second optical system including a third glass plate and a fourth glass plate,

wherein a third length of the third glass plate is different from a fourth length of the fourth glass plate,

wherein the third glass plate and the fourth glass plate are arranged in a second direction, and

wherein a short-side direction of a laser beam is substantially parallel to the second direction.

5. The laser irradiation device according to claim 1, wherein the laser irradiation device is capable of being used for forming a film that includes polycrystal.

6. A laser irradiation device comprising:

a laser source;

a first cylindrical lens;

a second cylindrical lens;

an optical system interposed between the first cylindrical lens and the second cylindrical lens, the optical system including a first glass plate and a second glass plate,

wherein a first length of the first glass plate is different from a second length of the second glass plate,

wherein the first glass plate and the second glass plate are arranged in a first direction, and

wherein a long-side direction of a laser beam is substantially parallel to the first direction.

7. The laser irradiation device according to claim 6, further comprising:

a light guide between the laser source and the first cylindrical lens.

8. The laser irradiation device according to claim 6, further comprising:

a cylindrical lens array between the first cylindrical lens and the second cylindrical lens.

9. The laser irradiation device according to claim 6, further comprising:

a second optical system between the first cylindrical lens and the second cylindrical lens, the second optical system including a third glass plate and a fourth glass plate,

wherein a third length of the third glass plate is different from a fourth length of the fourth glass plate,

wherein the third glass plate and the fourth glass plate are arranged in a second direction, and

wherein a short-side direction of the laser beam is substantially parallel to the second direction.

10. The laser irradiation device according to claim 6, wherein the laser irradiation device is capable of being used for forming a film that includes polycrystal.

11. A laser irradiation device comprising:

a solid laser source;

a first cylindrical lens;

a second cylindrical lens;

an optical system interposed between the first cylindrical lens and the second cylindrical lens, the optical system including a first glass plate and a second glass plate,

wherein a first length of the first glass plate is different from a second length of the second glass plate,

wherein the first glass plate and the second glass plate are arranged in a first direction, and

wherein a long-side direction of a laser beam is substantially parallel to the first direction.

12. The laser irradiation device according to claim 11, further comprising a light guide between the solid laser source and the first cylindrical lens.

13. The laser irradiation device according to claim 11, further comprising a cylindrical lens array between the first cylindrical lens and the second cylindrical lens.

14. The laser irradiation device according to claim 11, further comprising:

a second optical system between the first cylindrical lens and the second cylindrical lens, the second optical system including a third glass plate and a fourth glass plate,

wherein a third length of the third glass plate is different from a fourth length of the fourth glass plate,

wherein the third glass plate and the fourth glass plate are arranged in a second direction, and

wherein a short-side direction of the laser beam is substantially parallel to the second direction.

15. The laser irradiation device according to claim 11, wherein the laser irradiation device is capable of being used for forming a film that includes polycrystal.