Liquid crystal display device

• US 20030164911A1
• Filed: 02/28/2003
• Published: 09/04/2003
• Est. Priority Date: 03/01/2002
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Eguchi, Shingo, Tsuji, Yuriko
• Granted Patent: US 7,212,265 B2
• Time in Patent Office: Days
• US Class Current: 349/113
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/13685 Top gates

Abstract

With an object of providing a transflective type liquid crystal display device having a transparent electrode of an uneven structure formed without particularly increasing steps, in fabricating the transflective type liquid crystal display device, a amorphous transparent conductive film is formed on a substrate, a crystalline portion is formed in the amorphous transparent conductive film to thereby form the transparent conductive film including the crystalline portion, a amorphous portion is removed at a film surface of the transparent conductive film including the crystalline portion to thereby form the transparent conductive film having an uneven shape formed by a remaining crystalline portion at a film surface and a reflecting electrode having the uneven shape is formed by forming a reflective conductive film above the transparent electrode having the uneven shape.

Claims

1. A liquid crystal display device comprising:

a transparent electrode having uneven surface over a substrate;

a reflection electrode formed on the transparent electrode; and

liquid crystal over the transparent electrode and the reflection electrode.

2. A liquid crystal display device according to claim 1, wherein the transparent electrode having uneven surface is formed by forming an amorphous transparent conductive film over a substrate, forming a crystalline portion in the amorphous transparent conductive film, and removing an amorphous portion at a surface of the transparent conductive film including the-crystalline portion.

3. A liquid crystal display device according to claim 1, wherein the transparent electrode having uneven surface is formed by forming an amorphous transparent conductive film over a substrate, forming a crystalline portion in the amorphous transparent conductive film by sintering, and removing an amorphous portion at a surface of the transparent conductive film including the crystalline portion by etching.

4. A liquid crystal display device according to claim 3, wherein the sintering step is conducted at 150 through 200°

C.

5. A liquid crystal display device according to claim 3, wherein the etching step is conducted by using one or a plural kinds of acidic solution selected from the group constituting of hydrofluoric acid, nitric acid, sulfuric acid, and hydrochloric acid.

6. A liquid crystal display device according to claim 1, wherein the transparent electrode having uneven surface is formed by forming an amorphous transparent conductive film over a substrate, forming a crystalline portion in the amorphous transparent conductive film by sintering, polishing the transparent conductive film including the crystalline portion, and etching the transparent conductive film including the crystalline portion.

7. A liquid crystal display device according to claim 6, the polishing step is conducted by CMP.

8. A liquid crystal display device according to claim 1, wherein a rate of an area occupied by the reflection electrode is 50 through 90% of an area occupied by the transparent electrode.

9. A liquid crystal display device according to claim 1, wherein the liquid crystal display device is incorporated into an electronic device selected from the group constituting of a digital still camera, a notebook type personal computer, a mobile computer, a portable image reproducing device having a record medium, a video camera, and a portable telephone.

41. A method according to claim 3, wherein the sintering step is conducted at 150 through 200°

C.

48. A method according to claim 6, the polishing step is conducted by CMP.

49. A method according to claim 1, wherein a rate of an area occupied by the reflection electrode is 50 through 90% of an area occupied by the transparent electrode.

50. A method according to claim 1, wherein the liquid crystal display device is incorporated into an electronic device selected from the group constituting of a digital still camera, a notebook type personal computer, a mobile computer, a portable image reproducing device having a record medium, a video camera, and a portable telephone.

10. A liquid crystal display device comprising:

a thin film transistor formed over a substrate;

a transparent electrode having uneven surface over the thin film transistor;

a reflection electrode formed on the transparent electrode; and

liquid crystal over the transparent electrode and the reflection electrode,

wherein the thin film transistor is electrically connected to the transparent electrode and the reflection electrode.

11. A liquid crystal display device according to claim 10, wherein the transparent electrode having uneven surface is formed by forming an amorphous transparent conductive film over a substrate, forming a crystalline portion in the amorphous transparent conductive film, and removing an amorphous portion at a surface of the transparent conductive film including the crystalline portion.

12. A liquid crystal display device according to claim 10, wherein the transparent electrode having uneven surface is formed by forming an amorphous transparent conductive film over a substrate, forming a crystalline portion in the amorphous transparent conductive film by sintering, and removing an amorphous portion at a surface of the transparent conductive film including the crystalline portion by etching.

13. A liquid crystal display device according to claim 12, wherein the sintering step is conducted at 150 through 200°

C.

14. A liquid crystal display device according to claim 12, wherein the etching step is conducted by using one or a plural kinds of acidic solution selected from the group constituting of hydrofluoric acid, nitric acid, sulfuric acid, and hydrochloric acid.

15. A liquid crystal display device according to claim 10, wherein the transparent electrode having uneven surface is formed by forming an amorphous transparent conductive film over a substrate, forming a crystalline portion in the amorphous transparent conductive film by sintering, polishing the transparent conductive film including the crystalline portion, and etching the transparent conductive film including the crystalline portion.

16. A liquid crystal display device according to claim 15, the polishing step is conducted by CMP.

17. A liquid crystal display device according to claim 10, wherein a rate of an area occupied by the reflection electrode is 50 through 90% of an area occupied by the transparent electrode.

18. A liquid crystal display device according to claim 10, wherein the liquid crystal display device is incorporated into an electronic device selected from the group constituting of a digital still camera, a notebook type personal computer, a mobile computer, a portable image reproducing device having a record medium, a video camera, and a portable telephone.

19. A liquid crystal display device comprising:

a first substrate comprising a first transparent electrode having uneven surface and a reflection electrode formed on the first transparent electrode;

a second substrate comprising a second transparent electrode; and

a liquid crystal;

wherein electrodes forming face of the first substrate and an electrode forming face of the second substrate are arranged to be opposed to each other and the liquid crystal is interposed between the first substrate and the second substrate.

20. A liquid crystal display device according to claim 19, wherein the transparent electrode having uneven surface is formed by forming an amorphous transparent conductive film over a substrate, forming a crystalline portion in the amorphous transparent conductive film, and removing an amorphous portion at a surface of the transparent conductive film including the crystalline portion.

21. A liquid crystal display device according to claim 19, wherein the transparent electrode having uneven surface is formed by forming an amorphous transparent conductive film over a substrate, forming a crystalline portion in the amorphous transparent conductive film by sintering, and removing an amorphous portion at a surface of the transparent conductive film including the crystalline portion by etching.

22. A liquid crystal display device according to claim 21, wherein the sintering step is conducted at 150 through 200°

C.

23. A liquid crystal display device according to claim 21, wherein the etching step is conducted by using one or a plural kinds of acidic solution selected from the group constituting of hydrofluoric acid, nitric acid, sulfuric acid, and hydrochloric acid.

24. A liquid crystal display device according to claim 19, wherein the transparent electrode having uneven surface is formed by forming an amorphous transparent conductive film over a substrate, forming a crystalline portion in the amorphous transparent conductive film by sintering, polishing the transparent conductive film including the crystalline portion, and etching the transparent conductive film including the crystalline portion.

25. A liquid crystal display device according to claim 24, the polishing step is conducted by CMP.

26. A liquid crystal display device according to claim 19, wherein a rate of an area occupied by the reflection electrode is 50 through 90% of an area occupied by the transparent electrode.

27. A liquid crystal display device according to claim 19, wherein the liquid crystal display device is incorporated into an electronic device selected from the group constituting of a digital still camera, a notebook type personal computer, a mobile computer, a portable image reproducing device having a record medium, a video camera, and a portable telephone.

34. A liquid crystal display device according to claim 24, the polishing step is conducted by CMP.

28. A liquid crystal display device comprising:

a first substrate comprising a thin film transistor, a first transparent electrode having uneven surface over the thin film transistor, and a reflection electrode formed on the first transparent electrode;

a second substrate comprising a second transparent electrode; and

a liquid crystal;

wherein electrodes forming face of the first substrate and an electrode forming face of the second substrate are arranged to be opposed to each other and the liquid crystal is interposed between the first substrate and the second substrate,

wherein the thin film transistor is electrically connected to the first transparent electrode and the reflection electrode.

29. A liquid crystal display device according to claim 28, wherein the transparent electrode having uneven surface is formed by forming an amorphous transparent conductive film over a substrate, forming a crystalline portion in the amorphous transparent conductive film, and removing an amorphous portion at a surface of the transparent conductive film including the crystalline portion.

30. A liquid crystal display device according to claim 28, wherein the transparent electrode having uneven surface is formed by forming an amorphous transparent conductive film over a substrate, forming a crystalline portion in the amorphous transparent conductive film by sintering, and removing an amorphous portion at a surface of the transparent conductive film including the crystalline portion by etching.

31. A liquid crystal display device according to claim 30, wherein the sintering step is conducted at 150 through 200°

C.

32. A liquid crystal display device according to claim 30, wherein the etching step is conducted by using one or a plural kinds of acidic solution selected from the group constituting of hydrofluoric acid, nitric acid, sulfuric acid, and hydrochloric acid.

33. A liquid crystal display device according to claim 28, wherein the transparent electrode having uneven surface is formed by forming an amorphous transparent conductive film over a substrate, forming a crystalline portion in the amorphous transparent conductive film by sintering, polishing the transparent conductive film including the crystalline portion, and etching the transparent conductive film including the crystalline portion.

35. A liquid crystal display device according to claim 28, wherein a rate of an area occupied by the reflection electrode is 50 through 90% of an area occupied by the transparent electrode.

36. A liquid crystal display device according to claim 28, wherein the liquid crystal display device is incorporated into an electronic device selected from the group constituting of a digital still camera, a notebook type personal computer, a mobile computer, a portable image reproducing device having a record medium, a video camera, and a portable telephone.

37. A method of manufacturing a liquid crystal display device comprising:

forming an amorphous transparent conductive film over a substrate;

forming a crystalline portion in the amorphous transparent conductive film;

removing an amorphous portion at a surface of the transparent conductive film including the crystalline portion.

forming a reflection electrode on the transparent conductive film including the crystalline portion; and

forming liquid crystal layer over the transparent conductive film including the crystalline portion and the reflection electrode.

38. A method according to claim 37, wherein a rate of an area occupied by the reflection electrode is 50 through 90% of an area occupied by the transparent electrode.

39. A method according to claim 37, wherein the liquid crystal display device is incorporated into an electronic device selected from the group constituting of a digital still camera, a notebook type personal computer, a mobile computer, a portable image reproducing device having a record medium, a video camera, and a portable telephone.

40. A method of manufacturing a liquid crystal display device comprising:

forming an amorphous transparent conductive film over a substrate;

forming a crystalline portion in the amorphous transparent conductive film by sintering;

removing an amorphous portion at a surface of the transparent conductive film including the crystalline portion by etching;

forming a reflection electrode formed on the transparent conductive film including the crystalline portion; and

forming liquid crystal layer over the transparent conductive film including the crystalline portion and the reflection electrode.

42. A method according to claim 40, wherein the etching step is conducted by using one or a plural kinds of acidic solution selected from the group constituting of hydrofluoric acid, nitric acid, sulfuric acid, and hydrochloric acid.

43. A liquid crystal display device according to claim 40, wherein a rate of an area occupied by the reflection electrode is 50 through 90% of an area occupied by the transparent electrode.

44. A liquid crystal display device according to claim 40, wherein the liquid crystal display device is incorporated into an electronic device selected from the group constituting of a digital still camera, a notebook type personal computer, a mobile computer, a portable image reproducing device having a record medium, a video camera, and a portable telephone.

45. A method of manufacturing a liquid crystal display device comprising:

forming an amorphous transparent conductive film over a substrate;

forming a crystalline portion in the amorphous transparent conductive film by sintering;

polishing the transparent conductive film including the crystalline portion;

etching the transparent conductive film including the crystalline portion;

forming a reflection electrode formed on the transparent conductive film including the crystalline portion; and

forming liquid crystal layer over the transparent conductive film including the crystalline portion and the reflection electrode.

46. A method according to claim 45, wherein the sintering step is conducted at 150 through 200°

C.

47. A method according to claim 45, wherein the etching step is conducted by using one or a plural kinds of acidic solution selected from the group constituting of hydrofluoric acid, nitric acid, sulfuric acid, and hydrochloric acid.

51. A method of manufacturing a liquid crystal display device comprising:

forming a thin film transistor over a substrate;

forming an amorphous transparent conductive film over the thin film transistor;

forming a crystalline portion in the amorphous transparent conductive film;

removing an amorphous portion at a surface of the transparent conductive film including the crystalline portion;

forming a reflection electrode formed on the transparent conductive film including the crystalline portion; and

forming a liquid crystal layer over the transparent conductive film including the crystalline portion and the reflection electrode,

wherein the thin film transistor is electrically connected to the transparent conductive film including the crystalline portion and the reflection electrode.

52. A method according to claim 51, wherein step of forming a crystalline portion in the amorphous transparent conductive film is conducted by sintering.

53. A liquid crystal display device according to claim 52, wherein the sintering step is conducted at 150 through 200°

C.

54. A liquid crystal display device according to claim 51, wherein the removing step is conducted by etching.

55. A method according to claim 54, wherein etching step is conducted by using one or a plural kinds of acidic solution selected from the group constituting of hydrofluoric acid, nitric acid, sulfuric acid, and hydrochloric acid.

56. A liquid crystal display device according to claim 51, wherein the liquid crystal display device is incorporated into an electronic device selected from the group constituting of a digital still camera, a notebook type personal computer, a mobile computer, a portable image reproducing device having a record medium, a video camera, and a portable telephone.

57. A method of manufacturing a liquid crystal display device comprising:

forming a transparent conductive film comprising a amorphous portion and a crystalline portion over a substrate;

removing the amorphous portion at a surface of the transparent conductive film;

forming a reflection electrode on the transparent conductive film; and

forming a liquid crystal layer over the transparent conductive film and the reflection electrode.

58. A method according to claim 57, wherein step of forming the transparent conductive film comprising a amorphous portion and a crystalline portion is conducted by sintering.

59. A liquid crystal display device according to claim 58, wherein the sintering step is conducted at 150 through 200°

C.

60. A liquid crystal display device according to claim 57, wherein the removing step is conducted by etching.

61. A method according to claim 60, wherein etching step is conducted by using one or a plural kinds of acidic solution selected from the group constituting of hydrofluoric acid, nitric acid, sulfuric acid, and hydrochloric acid.

62. A liquid crystal display device according to claim 57, wherein the liquid crystal display device is incorporated into an electronic device selected from the group constituting of a digital still camera, a notebook type personal computer, a mobile computer, a portable image reproducing device having a record medium, a video camera, and a portable telephone.