Method for manufacturing semiconductor device

• US 20070020826A1
• Filed: 09/25/2006
• Published: 01/25/2007
• Est. Priority Date: 08/30/2001
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei
• Granted Patent: US 7,422,987 B2
• Time in Patent Office: Days
• US Class Current: 438/151
• 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 21/02488 Insulating materials
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02609 Crystal orientation
• 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 21/02691 Scanning of a beam
• CPC Class Codes: H01L 21/268 using electromagnetic radiation, e.g. laser radiation
• CPC Class Codes: H01L 21/3221 of silicon bodies, e.g. for gettering
• 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: H01L 29/78684 having a semiconductor body comprising semiconductor materials of Group IV not being silicon, or alloys including an element of the group IV, e.g. Ge, SiN alloys, SiC alloys H01L29/7869 takes precedence

Abstract

It is an object of the invention to provide a technique forming a crystalline semiconductor film whose orientation is uniform by control of crystal orientation and obtaining a crystalline semiconductor film in which concentration of an impurity is reduced. A configuration of the invention is that a first semiconductor region is formed on a substrate having transparent characteristics of a visible light region, a barrier film is formed over the first semiconductor region, a heat retaining film covering a top and side surfaces of the first semiconductor region is formed through the barrier film, the first semiconductor region is crystallized by scanning of a continuous wave laser beam from one edge of the first semiconductor region to the other through the substrate, the heat retaining film and the barrier film are removed, then a second semiconductor region is formed as an active layer of TFT by etching the first semiconductor region. A pattern of the second semiconductor region formed by etching is formed in a manner that a scanning direction of the laser beam and a channel length direction of the TFT are arranged in almost the same direction in order to smooth drift of carriers.

Claims

1. A method for manufacturing a semiconductor device comprising:

forming a semiconductor region comprising silicon over a substrate;

forming a barrier film covering the semiconductor region;

forming a heat retaining film over the barrier film so that the heat retaining film covers top surface and side surfaces of the semiconductor region through the barrier film;

after forming the heat retaining film, crystallizing the semiconductor region by scanning a laser beam from one edge to another of the semiconductor region from the substrate side;

after crystallizing the semiconductor region, removing the heat retaining film and the barrier film; and

after removing the heat retaining film, etching the semiconductor region in a manner that a scanning direction of the laser beam and a channel length direction of a thin film transistor are arranged in the same direction.

2. The method for manufacturing a semiconductor device according to claim 1, wherein the scanning the laser beam comprises a plurality of overlapped laser beams on the substrate.

3. The method for manufacturing a semiconductor device according to claim 1, wherein a wavelength of the laser beam is in the range of 400 to 700 nm.

4. The method for manufacturing a semiconductor device according to claim 1, wherein harmonics of the laser beam radiated from a solid state laser oscillation apparatus is used.

5. The method for manufacturing a semiconductor device according to claim 1, wherein the semiconductor device is incorporated into an electronic apparatus selected from the group consisting of a television set, a video camera, a note type of personal computer, a Personal Digital Assistant, a sound reproducing system, a digital camera, a cellular phone, a front type of projector, a rear type of projector, and a electronic book.

35. The method for manufacturing a semiconductor device according to claim 1, wherein the laser beam is irradiated obliquely to a normal of the substrate.

41. The method for manufacturing a semiconductor device according to claim 1, wherein the laser beam is continuous wave.

6. A method for manufacturing a semiconductor device comprising:

forming a semiconductor region comprising silicon over a substrate;

forming a barrier film covering the semiconductor region;

forming a heat retaining film over the barrier film so that the heat retaining film covers top surface and side surfaces of the semiconductor region through the barrier film;

after forming the heat retaining film, crystallizing the semiconductor region by scanning a laser beam from one edge to another of the semiconductor region from the substrate side;

after crystallizing the semiconductor region, removing the heat retaining film;

after removing the heat retaining film, forming an amorphous semiconductor film over the semiconductor region;

after forming the amorphous semiconductor film, segregating a metallic element included in the semiconductor region to the amorphous semiconductor film by heat treatment;

after segregating the metallic element, removing the amorphous semiconductor film and the barrier film; and

after removing the amorphous semiconductor film, etching the semiconductor region in a manner that a scanning direction of the laser beam and a channel length direction of a thin film transistor are arranged in the same direction.

7. The method for manufacturing a semiconductor device according to claim 6, wherein the scanning the laser beam comprises a plurality of overlapped laser beams on the substrate.

8. The method for manufacturing a semiconductor device according to claim 6, wherein a wavelength of the laser beam is in the range of 400 to 700 nm.

9. The method for manufacturing a semiconductor device according to claim 6, wherein harmonics of the laser beam radiated from a solid state laser oscillation apparatus is used.

10. The method for manufacturing a semiconductor device according to claim 6, wherein the semiconductor device is incorporated into an electronic apparatus selected from the group consisting of a television set, a video camera, a note type of personal computer, a Personal Digital Assistant, a sound reproducing system, a digital camera, a cellular phone, a front type of projector, a rear type of projector, and a electronic book.

36. The method for manufacturing a semiconductor device according to claim 6, wherein the laser beam is irradiated obliquely to a normal of the substrate.

42. The method for manufacturing a semiconductor device according to claim 6, wherein the laser beam is continuous wave.

11. A method for manufacturing a semiconductor device comprising:

forming an amorphous semiconductor film comprising silicon over a substrate;

adding a catalytic element to the amorphous semiconductor film;

heating the amorphous semiconductor film to form a crystalline semiconductor film;

forming a semiconductor region by etching the crystalline semiconductor film;

forming a barrier film covering the semiconductor region;

forming a heat retaining film over the barrier film so that the heat retaining film covers top surface and side surfaces of the semiconductor region through the barrier film;

after forming the heat retaining film, scanning a laser beam from one edge to another of the semiconductor region from the substrate side in order to improve crystalline characteristics of the semiconductor region;

after scanning the laser beam, removing the heat retaining film and the barrier film; and

after removing the heat retaining film, etching the semiconductor region in a manner that a scanning direction of the laser beam and a channel length direction of a thin film transistor are arranged in the same direction.

12. The method for manufacturing a semiconductor device according to claim 11, wherein after scanning the laser beam, the heat retaining film is removed and gettering treatment is performed for removing the catalytic element.

13. The method for manufacturing a semiconductor device according to claim 11, wherein the scanning the laser beam comprises a plurality of overlapped laser beams on the substrate.

14. The method for manufacturing a semiconductor device according to claim 11, wherein a wavelength of the laser beam is in the range of 400 to 700 nm.

15. The method for manufacturing a semiconductor device according to claim 11, wherein harmonics of the laser beam radiated from a solid state laser oscillation apparatus is used.

16. The method for manufacturing a semiconductor device according to claim 11, wherein the semiconductor device is incorporated into an electronic apparatus selected from the group consisting of a television set, a video camera, a note type of personal computer, a Personal Digital Assistant, a sound reproducing system, a digital camera, a cellular phone, a front type of projector, a rear type of projector, and a electronic book.

37. The method for manufacturing a semiconductor device according to claim 11, wherein the laser beam is irradiated obliquely to a normal of the substrate.

43. The method for manufacturing a semiconductor device according to claim 11, wherein the laser beam is continuous wave.

17. A method for manufacturing a semiconductor device comprising:

forming an amorphous semiconductor film comprising silicon over a substrate;

selectively adding a catalytic element to the amorphous semiconductor film;

heating the amorphous semiconductor film to form a crystalline semiconductor film, wherein the amorphous semiconductor film is crystallized in a direction parallel to the substrate from a region where the catalytic element was selectively added;

forming a semiconductor region by etching the crystalline semiconductor film;

forming a barrier film covering the semiconductor region;

forming a heat retaining film over the barrier film so that the heat retaining film covers top surface and side surfaces of the semiconductor region through the barrier film;

after forming the heat retaining film, scanning a laser beam from one edge to another of the semiconductor region from the substrate side in order to improve crystalline characteristics of the semiconductor region;

after scanning the laser beam, removing the heat retaining film and the barrier film; and

after removing the heat retaining film, etching the semiconductor region in a manner that a scanning direction of the laser beam and a channel length direction of a thin film transistor are arranged in the same direction.

18. The method for manufacturing a semiconductor device according to claim 17, wherein after scanning the laser beam, the heat retaining film is removed and gettering treatment is performed for removing the catalytic element.

19. The method for manufacturing a semiconductor device according to claim 17, wherein the scanning the laser beam comprises a plurality of overlapped laser beams on the substrate.

20. The method for manufacturing a semiconductor device according to claim 17, wherein a wavelength of the laser beam is in the range of 400 to 700 nm.

21. The method for manufacturing a semiconductor device according to claim 17, wherein harmonics of the laser beam radiated from a solid state laser oscillation apparatus is used.

22. The method for manufacturing a semiconductor device according to claim 17, wherein the semiconductor device is incorporated into an electronic apparatus selected from the group consisting of a television set, a video camera, a note type of personal computer, a Personal Digital Assistant, a sound reproducing system, a digital camera, a cellular phone, a front type of projector, a rear type of projector, and a electronic book.

38. The method for manufacturing a semiconductor device according to claim 17, wherein the laser beam is irradiated obliquely to a normal of the substrate.

44. The method for manufacturing a semiconductor device according to claim 17, wherein the laser beam is continuous wave.

23. A method for manufacturing a semiconductor device comprising:

forming a first amorphous semiconductor film over a substrate;

adding a catalytic element to the first amorphous semiconductor film;

heating the first amorphous semiconductor film to form a crystalline semiconductor film;

forming a seed crystal region by etching the crystalline semiconductor film;

forming a second amorphous semiconductor film comprising silicon over the substrate, overlapping with the seed crystal region,

etching the second amorphous semiconductor film to form a semiconductor region overlapping with the seed crystal region at least partly;

forming a barrier film covering the semiconductor region;

forming a heat retaining film over the barrier film so that the heat retaining film covers top surface and side surfaces of the semiconductor region through the barrier film;

after forming the heat retaining film, crystallizing the semiconductor region by scanning a laser beam from one edge overlapping with the seed region to another of the semiconductor region from the substrate side;

after crystallizing the semiconductor region, removing the heat retaining film and the barrier film; and

after removing the heat retaining film, etching the semiconductor region and the seed crystal region in a manner that a scanning direction of the laser beam and a channel length direction of a thin film transistor are arranged in the same direction.

24. The method for manufacturing a semiconductor device according to claim 23, wherein after crystallizing the semiconductor region, the heat retaining film is removed and gettering treatment is performed for removing the catalytic element.

25. The method for manufacturing a semiconductor device according to claim 23, wherein the scanning the laser beam comprises a plurality of overlapped laser beams on the substrate.

26. The method for manufacturing a semiconductor device according to claim 23, wherein a wavelength of the laser beam is in the range of 400 to 700 nm.

27. The method for manufacturing a semiconductor device according to claim 23, wherein harmonics of the laser beam radiated from a solid state laser oscillation apparatus is used.

28. The method for manufacturing a semiconductor device according to claim 23, wherein the semiconductor device is incorporated into an electronic apparatus selected from the group consisting of a television set, a video camera, a note type of personal computer, a Personal Digital Assistant, a sound reproducing system, a digital camera, a cellular phone, a front type of projector, a rear type of projector, and a electronic book.

39. The method for manufacturing a semiconductor device according to claim 23, wherein the laser beam is irradiated obliquely to a normal of the substrate.

45. The method for manufacturing a semiconductor device according to claim 23, wherein the laser beam is continuous wave.

47. The method for manufacturing a semiconductor device according to claim 23, wherein the seed crystal region has a shape projected from the semiconductor region.

29. A method for manufacturing a semiconductor device comprising:

forming a first amorphous semiconductor film containing silicon and germanium over a substrate,

adding a catalytic element to the first amorphous semiconductor film;

heating the first amorphous semiconductor film to form a crystalline semiconductor film;

forming a seed crystal region by etching the crystalline semiconductor film;

forming a second amorphous semiconductor film comprising silicon over the substrate, overlapping with the seed crystal region;

etching the second amorphous semiconductor film to form a semiconductor region overlapping with the seed crystal region at least partly;

forming a barrier film covering the semiconductor region;

forming a heat retaining film over the barrier film so that the heat retaining film covers top surface and side surfaces of the semiconductor region through the barrier film;

after forming the heat retaining film, crystallizing the semiconductor region by scanning a laser beam from one edge to another of the semiconductor region through the substrate;

after crystallizing the semiconductor region, removing the retaining film and the barrier film; and

after removing the retaining film, etching the semiconductor region and the seed crystal region in a manner that a scanning direction of the laser beam and a channel length direction of a thin film transistor are arranged in the same direction.

30. The method for manufacturing a semiconductor device according to claim 29, wherein after crystallizing the semiconductor region, the heat retaining film is removed and gettering treatment is performed for removing the catalytic element.

31. The method for manufacturing a semiconductor device according to claim 29, wherein the scanning the laser beam comprises a plurality of overlapped laser beams on the substrate.

32. The method for manufacturing a semiconductor device according to claim 29, wherein a wavelength of the laser beam is in the range of 400 to 700 nm.

33. The method for manufacturing a semiconductor device according to claim 29, wherein harmonics of the laser beam radiated from a solid state laser oscillation apparatus is used.

34. The method for manufacturing a semiconductor device according to claim 29, wherein the semiconductor device is incorporated into an electronic apparatus selected from the group consisting of a television set, a video camera, a note type of personal computer, a Personal Digital Assistant, a sound reproducing system, a digital camera, a cellular phone, a front type of projector, a rear type of projector, and a electronic book.

40. The method for manufacturing a semiconductor device according to claim 29, wherein the laser beam is irradiated obliquely to a normal of the substrate.

46. The method for manufacturing a semiconductor device according to claim 29, wherein the laser beam is continuous wave.

48. The method for manufacturing a semiconductor device according to claim 29, wherein the seed crystal region has a shape projected from the semiconductor region.