Laser irradiation method and method of manufacturing a semiconductor device

• US 7,560,397 B2
• Filed: 02/22/2007
• Issued: 07/14/2009
• Est. Priority Date: 12/11/2001
• Status: Expired due to Term

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Shibata, Hiroshi, Hiroki, Masaaki, Tanaka, Koichiro, Akiba, Mai, Yamazaki, Shunpei
• Primary Examiner(s): Garber; Charles D.
• Assistant Examiner(s): Isaac; Stanetta D
• Application Number:
  US11/709,200
• Publication Number:
  US 20070190810A1
• Time in Patent Office: 873 Days
• Field of Search: 438/164, 438/795, 257/E21.134, 257/E21.413, 257/E21.475
• US Class Current: 438/795
• CPC Class Codes: H01L 21/02381 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/0242 Crystalline insulating materials
• CPC Class Codes: H01L 21/02422 Non-crystalline insulating materials, e.g. glass, polymers
• CPC Class Codes: H01L 21/02425 Conductive materials, e.g. metallic silicides
• CPC Class Codes: H01L 21/02488 Insulating materials
• CPC Class Codes: H01L 21/02502 consisting of two layers
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02672 using crystallisation enhancing elements
• 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 27/12 the substrate being other than a semiconductor body, e.g. an insulating body
• CPC Class Codes: H01L 27/1281 by using structural features to control crystal growth, e.g. placement of grain filters
• 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 29/66757 Lateral single gate single channel transistors with non-inverted structure, i.e. the channel layer is formed before the gate
• CPC Class Codes: H01L 29/78621 with LDD structure or an extension or an offset region or characterised by the doping profile
• CPC Class Codes: H01L 29/78675 with normal-type structure, e.g. with top gate
• CPC Class Codes: Y10S 438/942 Masking

Abstract

A method of manufacturing a semiconductor device is provided which uses a laser crystallization method capable of increasing substrate processing efficiency. An island-like semiconductor film including one or more islands is formed by patterning (sub-island). The sub-island is then irradiated with laser light to improve its crystallinity, and thereafter patterned to form an island. From pattern information of a sub-island, a laser light scanning path on a substrate is determined such that at least the sub-island is irradiated with laser light. In other words, the present invention runs laser light so as to obtain at least the minimum degree of crystallization of a portion that has to be crystallized, instead of irradiating the entire substrate with laser light.

Claims

1. A laser irradiation method comprising:

determining, from pattern information of a sub-island obtained by patterning a semiconductor film formed over a substrate, a specific region on the substrate that is to be irradiated with laser light, the region including the sub-island;

using an optical system to partially overlap beam spots of plural laser lights that are outputted from plural laser oscillation apparatuses to form one beam spot;

using a slit to reduce a width in a direction perpendicular to a scanning direction of the beam spot formed;

running the beam spot with the reduced width over the specific region to enhance crystallinity of the sub-island wherein the sub-island is included in an area irradiated in the reduced width by the running of the beam spot; and

patterning the sub-island with enhanced crystallinity to form an island.

2. A laser irradiation method according to claim 1, wherein laser light irradiation takes place in a reduced pressure atmosphere or inert gas atmosphere.

3. A laser irradiation method according to claim 1, wherein the laser light is outputted from one or more kinds of lasers selected from the group consisting of a YAG laser, a YVO₄ laser, a YLF laser, a YAlO₃ laser, a glass laser, a ruby laser, an alexandrite laser, a Ti:

sapphire laser, and a Y₂O₃ laser.

4. A laser irradiation method according to claim 1, wherein the laser light is continuous wave laser light.

5. A laser irradiation method according to claim 1, wherein the number of the laser oscillation apparatuses is equal to or more than 2 and equal to or less than 8.

6. A laser irradiation method comprising:

determining, from pattern information of a sub-island obtained by patterning a semiconductor film formed over a substrate, a specific region on the substrate that is to be irradiated with laser light, the region including the sub-island;

using an optical system to partially overlap beam spots of plural laser lights that are outputted from plural laser oscillation apparatuses so that centers draw a straight line to form one beam spot;

using a slit to reduce a width in a direction perpendicular to a scanning direction of the beam spot formed;

running the beam spot with the reduced width over the specific region to enhance crystallinity of the sub-island wherein the sub-island is included in an area irradiated in the reduced width by the running of the beam spot; and

patterning the sub-island with enhanced crystallinity to form an island.

7. A laser irradiation method according to claim 6, wherein laser light irradiation takes place in a reduced pressure atmosphere or inert gas atmosphere.

8. A laser irradiation method according to claim 6, wherein the laser light is outputted from one or more kinds of lasers selected from the group consisting of a YAG laser, a YVO₄ laser, a YLF laser, a YAlO₃ laser, a glass laser, a ruby laser, an alexandrite laser, a Ti:

sapphire laser, and a Y₂O₃ laser.

9. A laser irradiation method according to claim 6, wherein the laser light is second harmonic.

10. A laser irradiation method according to claim 6, wherein the number of the laser oscillation apparatuses is equal to or more than 2 and equal to or less than 8.

11. A laser irradiation method comprising:

patterning a semiconductor film formed over a substrate to form a sub-island using a mask;

detecting pattern information of the sub-island using a CCD;

grasping a position of the substrate by checking pattern information of the mask against the detected pattern information of the sub-island;

determining, from the pattern information of the sub-island, a specific region on the substrate that is to be irradiated with a laser beam spot, the region including the sub-island;

using an optical system to partially overlap beam spots of plural laser lights that are outputted from plural laser oscillation apparatuses to form one beam spot as the laser beam spot;

using a slit to reduce a width in a direction perpendicular to a scanning direction of the beam spot formed;

running the beam spot with the reduced width over the specific region to enhance crystallinity of the sub-island wherein the sub-island is included in an area irradiated in the reduced width by the running of the beam spot; and

patterning the sub-island with enhanced crystallinity to form an island.

12. A laser irradiation method according to claim 11, wherein laser light irradiation takes place in a reduced pressure atmosphere or inert gas atmosphere.

13. A laser irradiation method according to claim 11, wherein at least one of the plural laser oscillation apparatuses is selected from the group consisting of a YAG laser, a YVO₄ laser, a YLF laser, a YAlO₃ laser, a glass laser, a ruby laser, an alexandrite laser, a Ti:

sapphire laser, and a Y₂O₃ laser.

14. A laser irradiation method according to claim 11, wherein the laser lights are continuous wave laser lights.

15. A laser irradiation method according to claim 11, wherein the number of the laser oscillation apparatuses is equal to or more than 2 and equal to or less than 8.

16. A laser irradiation method comprising:

patterning a semiconductor film formed over a substrate to form a sub-island using a mask;

detecting pattern information of the sub-island using a CCD;

grasping a position of the substrate by checking pattern information of the mask against the detected pattern information of the sub-island;

determining, from the pattern information of the sub-island, a specific region on the substrate that is to be irradiated with a laser beam spot, the region including the sub-island;

using an optical system to partially overlap beam spots of plural laser lights that are outputted from plural laser oscillation apparatuses so that centers draw a straight line to form one beam spot as the laser beam spot;

using a slit to reduce a width in a direction perpendicular to a scanning direction of the beam spot formed;

running the beam spot with the reduced width over the specific region to enhance crystallinity of the sub-island wherein the sub-island is included in an area irradiated in the reduced width by the running of the beam spot; and

patterning the sub-island with enhanced crystallinity to form an island.

17. A laser irradiation method according to claim 16, wherein laser light irradiation takes place in a reduced pressure atmosphere or inert gas atmosphere.

18. A laser irradiation method according to claim 16, wherein at least one of the plural laser oscillation apparatuses is selected from the group consisting of a YAG laser, a YVO₄ laser, a YLF laser, a YAlO₃ laser, a glass laser, a ruby laser, an alexandrite laser, a Ti:

sapphire laser, and a Y₂O₃ laser.

19. A laser irradiation method according to claim 16, wherein the laser lights are second harmonic.

20. A laser irradiation method according to claim 16, wherein the number of the laser oscillation apparatuses is equal to or more than 2 and equal to or less than 8.

21. A laser irradiation method comprising:

determining, from pattern information of a sub-island obtained by patterning a semiconductor film formed over a substrate with a marker as the reference, a specific region on the substrate that is to be irradiated with laser light, the region including the sub-island;

using an optical system to partially overlap beam spots of plural laser lights that are outputted from plural laser oscillation apparatuses to form one beam spot;

using a slit to reduce a width in a direction perpendicular to a scanning direction of the beam spot formed;

running the beam spot with the reduced width over the specific region to enhance crystallinity of the sub-island wherein the sub-island is included in an area irradiated in the reduced width by the running of the beam spot; and

patterning the sub-island with enhanced crystallinity to form an island.

23. A laser irradiation method according to claim 21, wherein the straight lines the centers draw are at angles of 10°

or larger and 80°

or less with the direction in which the substrate moves.

25. A laser irradiation method according to claim 21, wherein the straight lines the centers draw are almost at right angles with the direction in which the substrate moves.

27. A laser irradiation method according to claim 21, wherein laser light irradiation takes place in a reduced pressure atmosphere or inert gas atmosphere.

29. A laser irradiation method according to claim 21, wherein the laser light is outputted from one or more kinds of lasers selected from the group consisting of a YAG laser, a YVO₄ laser, a YLF laser, a YAlO₃ laser, a glass laser, a ruby laser, an alexandrite laser, a Ti:

sapphire laser, and a Y₂O₃ laser.

31. A laser irradiation method according to claim 21, wherein the laser light is continuous wave laser light.

33. A laser irradiation method according to claim 21, wherein the number of the laser oscillation apparatuses is equal to or more than 2 and equal to or less than 8.

22. A laser irradiation method comprising:

determining, from pattern information of the sub-island obtained by patterning a semiconductor film formed over a substrate with the marker as the reference, a specific region on the substrate that is to be irradiated with laser light, the region including the sub-island;

using an optical system to partially overlap beam spots of plural laser lights that are outputted from plural laser oscillation apparatuses so that centers draw straight lines to form one beam spot;

using a slit to reduce the width in the direction perpendicular to the scanning direction of the beam spot formed;

running the beam spot with the reduced width over the specific region to enhance crystallinity of the sub-island wherein the sub-island is included in an area irradiated in the reduced width by the running of the beam spot; and

patterning the sub-island with enhanced crystallinity to form an island.

24. A laser irradiation method according to claim 22, wherein the straight lines the centers draw are at angles of 10°

or larger and 80°

or less with the direction in which the substrate moves.

26. A laser irradiation method according to claim 22, wherein the straight lines the centers draw are almost at right angles with the direction in which the substrate moves.

28. A laser irradiation method according to claim 22, wherein laser light irradiation takes place in a reduced pressure atmosphere or inert gas atmosphere.

30. A laser irradiation method according to claim 22, wherein the laser light is outputted from one or more kinds of lasers selected from the group consisting of a YAG laser, a YVO₄ laser, a YLF laser, a YAlO₃ laser, a glass laser, a ruby laser, an alexandrite laser, a Ti:

sapphire laser, and a Y₂O₃ laser.

32. A laser irradiation method according to claim 22, wherein the laser light is second harmonic.

34. A laser irradiation method according to claim 22, wherein the number of the laser oscillation apparatuses is equal to or more than 2 and equal to or less than 8.