Laser annealing apparatus and annealing method of semiconductor thin film using the same

• US 20050170572A1
• Filed: 11/15/2004
• Published: 08/04/2005
• Est. Priority Date: 01/30/2004
• Status: Active Grant

• Current Assignee: Panasonic Liquid Crystal Display Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Hitachi Displays Limited (Japan Display Incorporated)
• Inventors: Hatano, Mutsuko, Hongo, Mikio, Yazaki, Akio
• Granted Patent: US 7,397,831 B2
• Time in Patent Office: Days
• US Class Current: 438/166
• CPC Class Codes: B23K 26/0738 into a linear shape
• CPC Class Codes: B23K 26/0853 Devices involving movement of the workpiece in at least in two axial directions, e.g. in a plane
• CPC Class Codes: G02B 27/0927 Systems for changing the beam intensity distribution, e.g. Gaussian to top-hat
• CPC Class Codes: G02B 27/0966 Cylindrical lenses cylindrical lenses per se G02B3/06
• CPC Class Codes: H01L 21/02422 Non-crystalline insulating materials, e.g. glass, polymers
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02595 polycrystalline
• CPC Class Codes: H01L 21/02678 Beam shaping, e.g. using a mask
• CPC Class Codes: H01L 21/02683 Continuous wave laser beam
• CPC Class Codes: H01L 21/02686 Pulsed laser beam
• CPC Class Codes: H01L 21/02691 Scanning of a beam
• 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
• CPC Class Codes: H01L 27/1296 adapted to increase the uniformity of device parameters

Abstract

A laser beam temporally modulated in amplitude by a modulator and shaped into a long and narrow shape by a beam shaper is rotated around the optical axis of an image rotator inserted between the beam shaper and a substrate. Thus, the longitudinal direction of the laser beam having the long and narrow shape is rotated around the optical axis on the substrate. In order to perform annealing in a plurality of directions on the substrate, the laser beam shaped into the long and narrow shape is rotated on the substrate while a stage mounted with the substrate is moved only in two directions, that is, X- and Y-directions. In such a manner, the substrate can be scanned at a high speed with a continuous wave laser beam modulated temporally in amplitude and shaped into a long and narrow shape, without rotating the substrate. Thus, a semiconductor film can be annealed.

Claims

1. A laser annealing apparatus comprising:

a stage for moving a substrate mounted thereon in two directions crossing each other at right angles;

a laser oscillator for oscillating a laser beam;

a beam shaper for shaping said laser beam into a long and narrow shape;

an imaging lens disposed in a positional relationship such that said laser beam shaped into said long and narrow shape is projected onto said substrate mounted on said stage; and

a unit for rotating said laser beam shaped into said long and narrow shape around an optical axis of said laser beam.

3. A laser annealing apparatus according to claim 1, wherein said unit for rotating said laser beam shaped into said long and narrow shape around said optical axis of said laser beam is an image rotator inserted after said beam shaper for shaping said laser beam into a linear shape or a rectangular shape and before said imaging lenses.

5. A laser annealing apparatus according to claim 3, wherein said beam shaper for shaping said laser beam into said long and narrow shape is one of a combination of a Powell'"'"'s lens and a cylindrical lens, a kaleidoscope, a diffractive optical element, and a combination of a multi-lens array and a cylindrical lens.

7. A laser annealing apparatus according to claim 1, wherein said unit for rotating said laser beam shaped into said long and narrow shape around said optical axis is a mechanism by which at least said beam shaper for shaping said laser beam into said long and narrow shape can be rotated desirably around said optical axis of said laser beam.

9. A laser annealing apparatus according to claim 1, wherein said beam shaper for shaping said laser beam into said long and narrow shape is one of a combination of a Powell'"'"'s lens and a cylindrical lens, a kaleidoscope, and a diffractive optical element.

11. A laser annealing apparatus according to claim 1, wherein said laser oscillator is an oscillator for generating a continuous wave laser beam, and a temporal amplitude modulator is placed before said beam shaper for shaping said laser beam into said long and narrow shape so that said continuous wave laser beam temporally modulated in amplitude by said temporal amplitude modulator can be shaped into said long and narrow shape.

2. A laser annealing apparatus comprising:

a stage for moving a substrate mounted thereon in two directions crossing each other at right angles;

a laser oscillator for oscillating a laser beam;

a beam shaper for shaping said laser beam into a long and narrow shape;

a relay lens for converting said laser beam shaped into said long and narrow shape to a collimated beam;

an imaging lens disposed in a positional relationship such that said collimated laser beam is projected onto said substrate mounted on said stage in a state where said laser beam has been shaped into said long and narrow shape; and

a unit for rotating said laser beam shaped into said long and narrow shape around an optical axis of said laser beam.

4. A laser annealing apparatus according to claim 2, wherein said unit for rotating said laser beam shaped into said long and narrow shape around said optical axis of said laser beam is an image rotator inserted after said beam shaper for shaping said laser beam into a linear shape or a rectangular shape and before said imaging lenses.

6. A laser annealing apparatus according to claim 4, wherein said beam shaper for shaping said laser beam into said long and narrow shape is one of a combination of a Powell'"'"'s lens and a cylindrical lens, a kaleidoscope, a diffractive optical element, and a combination of a multi-lens array and a cylindrical lens.

8. A laser annealing apparatus according to claim 2, wherein said unit for rotating said laser beam shaped into said long and narrow shape around said optical axis is a mechanism by which at least said beam shaper for shaping said laser beam into said long and narrow shape can be rotated desirably around said optical axis of said laser beam.

10. A laser annealing apparatus according to claim 2, wherein said beam shaper for shaping said laser beam into said long and narrow shape is one of a combination of a Powell'"'"'s lens and a cylindrical lens, a kaleidoscope, and a diffractive optical element.

12. A laser annealing method comprising the steps of:

mounting a substrate on a stage, said substrate having an amorphous silicon film or a polycrystalline silicon film formed in one principal surface thereof; and

scanning a desired region of said amorphous silicon film or said polycrystalline silicon film on said substrate while irradiating said desired region with a laser beam shaped into a long and narrow shape;

wherein in order to scan said substrate with said laser beam in a plurality of directions, said laser beam shaped into said long and narrow shape is rotated around an optical axis of said laser beam without rotating said substrate, while said stage mounted with said substrate is moved only in two directions crossing each other at right angles, so that said desired region can be irradiated at any position and in any direction with said laser beam shaped into said long and narrow shape.

13. A laser annealing method according to claim 12, wherein said laser beam to irradiate said substrate having said amorphous silicon film or said polycrystalline silicon film on said principal surface is a continuous wave laser beam modulated temporally in amplitude and shaped into a long and narrow shape.

14. A laser annealing method according to claim 12, wherein said laser beam to irradiate said substrate having said amorphous silicon film or said polycrystalline silicon film on said principal surface is a laser beam pulsed and shaped into a long and narrow shape.