Semiconductor circuit and method of fabricating the same

• US 20070099400A1
• Filed: 12/01/2006
• Published: 05/03/2007
• Est. Priority Date: 03/26/2002
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Isobe, Atsuo, Atsumi, Tomoaki, Kato, Kiyoshi
• Granted Patent: US 7,704,812 B2
• Time in Patent Office: Days
• US Class Current: 438/486
• 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 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 29/78675 with normal-type structure, e.g. with top gate
• CPC Class Codes: H01L 29/78696 characterised by the structure of the channel, e.g. multichannel, transverse or longitudinal shape, length or width, doping structure, or the overlap or alignment between the channel and the gate, the source or the drain, or the contacting structure of the channel H01L29/78612 takes precedence; transistors having a drain offset region or a lightly doped drain [LDD] H01L29/78621

Abstract

According to the invention, a plurality of semiconductor devices which are required to have conformance are formed from crystalline semiconductor films having uniform crystallinity on the same line, and a semiconductor circuit in which variation between semiconductor devices is small can be provided, and a semiconductor integrated circuit having high conformance can be provided. The invention is characterized in that, in a part or whole of thin film transistors which configure an analog circuit such as a current mirror circuit, a differential amplifier circuit, or an operational amplifier, in which high conformance is required for semiconductor devices included therein, channel forming regions have crystalline semiconductor films on the same line. High conformance can be expected for an analog circuit which has the crystalline semiconductor films on the same line formed using the invention as the channel forming regions of the thin film transistors. That is, the invention is characterized in that, among the thin film transistors which configures the analog circuit, the channel forming regions of the thin film transistors having at least the same polarity are formed on the same line.

Claims

1. A method of fabricating a semiconductor device comprising:

forming a first insulating film over an insulating surface;

forming a second insulating film over the first insulating film;

forming at least first and second projections and a depression therebetween by patterning the second insulating film;

forming an amorphous semiconductor film over the first and second projections and the depression;

crystallizing the amorphous semiconductor film to form a crystalline semiconductor film by irradiating laser light to the amorphous semiconductor film; and

patterning the crystalline semiconductor film to form at least a first channel forming region for a first thin film transistor and a second channel forming region for a second thin film transistor, the first and second channel forming regions being located in the projection.

11. A method according to claim 1, wherein the laser light is a line-shaped continuous wave laser light.

21. A method according to claim 1, wherein the amorphous semiconductor film is melted and crystallized by the irradiation of the laser light so that a flat surface is formed.

31. A method according to claim 1, wherein an etching rate of the second insulating film is faster than that of quartz under the same measuring condition.

41. A method according to claim 1, wherein the hardness of the second insulating film is lower than that of quartz under the same measuring condition.

2. A method of fabricating a semiconductor device comprising:

forming a first insulating film over an insulating surface;

forming a second insulating film over the first insulating film;

forming at least first and second projections and a depression therebetween by patterning the second insulating film;

forming an amorphous semiconductor film over the first and second projections and the depression;

crystallizing the amorphous semiconductor film to form a crystalline semiconductor film by irradiating laser light to the amorphous semiconductor film; and

patterning the crystalline semiconductor film to form at least a first channel forming region for a first thin film transistor and a second channel forming region for a second thin film transistor, the first and second channel forming regions being located in the projection, wherein the first and second thin film transistors comprise gate electrodes having the same electric potentials.

12. A method according to claim 2, wherein the laser light is a line-shaped continuous wave laser light.

22. A method according to claim 2, wherein the amorphous semiconductor film is melted and crystallized by the irradiation of the laser light so that a flat surface is formed.

32. A method according to claim 2, wherein an etching rate of the second insulating film is faster than that of quartz under the same measuring condition.

42. A method according to claim 2, wherein the hardness of the second insulating film is lower than that of quartz under the same measuring condition.

3. A method of fabricating a semiconductor device comprising:

forming a first insulating film over an insulating surface;

forming a second insulating film over the first insulating film;

forming at least first and second projections and a depression therebetween by patterning the second insulating film;

forming an amorphous semiconductor film over the first and second projections and the depression;

crystallizing the amorphous semiconductor film to form a crystalline semiconductor film by irradiating laser light to the amorphous semiconductor film; and

patterning the crystalline semiconductor film to form at least a first channel forming region for a first thin film transistor and a second channel forming region for a second thin film transistor, the first and second channel forming regions being located in the projection, wherein the first and second thin film transistors comprise gate electrodes to which the same signals are inputted simultaneously.

13. A method according to claim 3, wherein the laser light is a line-shaped continuous wave laser light.

23. A method according to claim 3, wherein the amorphous semiconductor film is melted and crystallized by the irradiation of the laser light so that a flat surface is formed.

33. A method according to claim 3, wherein an etching rate of the second insulating film is faster than that of quartz under the same measuring condition.

43. A method according to claim 3, wherein the hardness of the second insulating film is lower than that of quartz under the same measuring condition.

4. A method of fabricating a semiconductor device comprising:

forming a first insulating film over an insulating surface;

forming a second insulating film over the first insulating film;

forming at least first and second projections and a depression therebetween by patterning the second insulating film;

forming an amorphous semiconductor film over the first and second projections and the depression;

crystallizing the amorphous semiconductor film to form a crystalline semiconductor film by irradiating laser light to the amorphous semiconductor film;

removing the crystalline semiconductor film formed over the first and second projections by etching; and

patterning the crystalline semiconductor film to form at least a first channel forming region for a first thin film transistor and a second channel forming region for a second thin film transistor, the first and second channel forming regions being located in the projection.

14. A method according to claim 4, wherein the laser light is a line-shaped continuous wave laser light.

24. A method according to claim 4, wherein the amorphous semiconductor film is melted and crystallized by the irradiation of the laser light so that a flat surface is formed.

34. A method according to claim 4, wherein an etching rate of the second insulating film is faster than that of quartz under the same measuring condition.

44. A method according to claim 4, wherein the hardness of the second insulating film is lower than that of quartz under the same measuring condition.

5. A method of fabricating a semiconductor device comprising:

forming a first insulating film over an insulating surface;

forming a second insulating film over the first insulating film;

forming at least first and second projections and a depression therebetween by patterning the second insulating film;

forming an amorphous semiconductor film over the first and second projections and the depression;

crystallizing the amorphous semiconductor film to form a crystalline semiconductor film by irradiating laser light to the amorphous semiconductor film;

removing the crystalline semiconductor film formed over the first and second projections by etching; and

patterning the crystalline semiconductor film to form at least a first channel forming region for a first thin film transistor and a second channel forming region for a second thin film transistor, the first and second channel forming regions being located in the projection,

wherein the first and second thin film transistors comprise gate electrodes to which the same signals are inputted simultaneously.

15. A method according to claim 5, wherein the laser light is a line-shaped continuous wave laser light.

25. A method according to claim 5, wherein the amorphous semiconductor film is melted and crystallized by the irradiation of the laser light so that a flat surface is formed.

35. A method according to claim 5, wherein an etching rate of the second insulating film is faster than that of quartz under the same measuring condition.

45. A method according to claim 5, wherein the hardness of the second insulating film is lower than that of quartz under the same measuring condition.

6. A method of fabricating a semiconductor device having a first thin film transistor and a second thin film transistor, comprising:

forming a first insulating film over an insulating surface;

forming a second insulating film over the first insulating film;

forming first to forth projections from the second insulating film, a first depression between the first and second projections and a second depression between the third and the forth depressions;

forming an amorphous semiconductor film over the first and second depressions and the first to forth projections;

crystallizing the amorphous semiconductor film to form a crystalline semiconductor film by irradiating laser light to the amorphous semiconductor film;

removing the crystalline semiconductor film formed over the first to fourth projections by etching; and

patterning the crystalline semiconductor film to form a first channel forming region in the first depression and a second channel forming region in the second depression,

wherein the first and second channel forming regions are formed in a same line,

wherein the length of the first and second projections are the same as that of the fist channel forming region, and

wherein the length of the third and fourth projections are the same as that of the second channel forming region

16. A method according to claim 6, wherein the laser light is a line-shaped continuous wave laser light.

26. A method according to claim 6, wherein the amorphous semiconductor film is melted and crystallized by the irradiation of the laser light so that a flat surface is formed.

36. A method according to claim 6, wherein an etching rate of the second insulating film is faster than that of quartz under the same measuring condition.

46. A method according to claim 6, wherein the hardness of the second insulating film is lower than that of quartz under the same measuring condition.

7. A method of fabricating a semiconductor device having a first thin film transistor and a second thin film transistor, comprising:

forming a first insulating film over an insulating surface;

forming a second insulating film over the first insulating film;

forming first to forth projections from the second insulating film, a first depression between the first and second projections and a second depression between the third and the forth depressions;

forming an amorphous semiconductor film over the first and second depressions and the first to forth projections;

crystallizing the amorphous semiconductor film to form a crystalline semiconductor film by irradiating laser light to the amorphous semiconductor film;

removing the crystalline semiconductor film formed over the first to fourth projections by etching; and

patterning the crystalline semiconductor film to form a first channel forming region in the first depression and a second channel forming region in the second depression,

wherein the first and second channel forming regions are formed in a same line,

wherein the length of the first and second projections are the same as that of the fist channel forming region,

wherein the length of the third and fourth projections are the same as that of the second channel forming region, and

wherein the first and second thin film transistors comprise gate electrodes having the same electric potentials.

17. A method according to claim 7, wherein the laser light is a line-shaped continuous wave laser light.

27. A method according to claim 7, wherein the amorphous semiconductor film is melted and crystallized by the irradiation of the laser light so that a flat surface is formed.

37. A method according to claim 7, wherein an etching rate of the second insulating film is faster than that of quartz under the same measuring condition.

47. A method according to claim 7, wherein the hardness of the second insulating film is lower than that of quartz under the same measuring condition.

8. A method of fabricating a semiconductor device having a first thin film transistor and a second thin film transistor, comprising:

forming a first insulating film over an insulating surface;

forming a second insulating film over the first insulating film;

forming first to forth projections from the second insulating film, a first depression between the first and second projections and a second depression between the third and the forth depressions;

forming an amorphous semiconductor film over the first and second depressions and the first to forth projections;

crystallizing the amorphous semiconductor film to form a crystalline semiconductor film by irradiating laser light to the amorphous semiconductor film;

removing the crystalline semiconductor film formed over the first to fourth projections by etching; and

patterning the crystalline semiconductor film to form a first channel forming region in the first depression and a second channel forming region in the second depression,

wherein the first and second channel forming regions are formed in a same line,

wherein the length of the first and second projections are the same as that of the fist channel forming region, and

wherein the length of the third and fourth projections are the same as that of the second channel forming region

wherein the first and second thin film transistors comprise gate electrodes to which the same signals are inputted simultaneously.

18. A method according to claim 8, wherein the laser light is a line-shaped continuous wave laser light.

28. A method according to claim 8, wherein the amorphous semiconductor film is melted and crystallized by the irradiation of the laser light so that a flat surface is formed.

38. A method according to claim 8, wherein an etching rate of the second insulating film is faster than that of quartz under the same measuring condition.

48. A method according to claim 8, wherein the hardness of the second insulating film is lower than that of quartz under the same measuring condition.

9. A method of fabricating a semiconductor device having a first thin film transistor and a second thin film transistor, comprising:

forming a first insulating film over an insulating surface;

forming a second insulating film over the first insulating film;

forming first to fourth projections from the second insulating film, a first depression between the first and second projections and a second depression between the third and the fourth depressions;

forming an amorphous semiconductor film over the first and second depressions and the first to fourth projections;

crystallizing the amorphous semiconductor film to form a crystalline semiconductor film by irradiating laser light to the amorphous semiconductor film; and

patterning the crystalline semiconductor film to form a first channel forming region in the first depression and a second channel forming region in the second depression,

wherein the first and second channel forming regions are formed in a same line.

19. A method according to claim 9, wherein the laser light is a line-shaped continuous wave laser light.

29. A method according to claim 9, wherein the amorphous semiconductor film is melted and crystallized by the irradiation of the laser light so that a flat surface is formed.

39. A method according to claim 9, wherein an etching rate of the second insulating film is faster than that of quartz under the same measuring condition.

49. A method according to claim 9, wherein the hardness of the second insulating film is lower than that of quartz under the same measuring condition.

51. A method according to claim 9, wherein the first and second thin film transistors comprise gate electrodes having the same electric potentials.

53. A method according to claim 9, wherein the first and second thin film transistors comprise gate electrodes to which the same signals are inputted simultaneously.

10. A method of fabricating a semiconductor device having a first thin film transistor and a second thin film transistor, comprising:

forming a first insulating film over an insulating surface;

forming a second insulating film over the first insulating film;

forming first to fourth projections from the second insulating film, a first depression between the first and second projections and a second depression between the third and the fourth depressions;

forming an amorphous semiconductor film over the first and second depressions and the first to fourth projections;

crystallizing the amorphous semiconductor film to form a crystalline semiconductor film by irradiating laser light to the amorphous semiconductor film;

removing the crystalline semiconductor film formed over the first to fourth projections by etching; and

patterning the crystalline semiconductor film to form a first channel forming region in the first depression and a second channel forming region in the second depression,

wherein the first and second channel forming regions are formed in a same line.

20. A method according to claim 10, wherein the laser light is a line-shaped continuous wave laser light.

30. A method according to claim 10, wherein the amorphous semiconductor film is melted and crystallized by the irradiation of the laser light so that a flat surface is formed.

40. A method according to claim 10, wherein an etching rate of the second insulating film is faster than that of quartz under the same measuring condition.

50. A method according to claim 10, wherein the hardness of the second insulating film is lower than that of quartz under the same measuring condition.

52. A method according to claim 10, wherein the first and second thin film transistors comprise gate electrodes having the same electric potentials.

54. A method according to claim 10, wherein the first and second thin film transistors comprise gate electrodes to which the same signals are inputted simultaneously.