Liquid crystal display device and manfacturing method thereof

• US 7,714,975 B1
• Filed: 05/09/2000
• Issued: 05/11/2010
• Est. Priority Date: 03/17/2000
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Hirakata, Yoshiharu, Yamazaki, Shunpei
• Primary Examiner(s): Duong; Thoi V
• Application Number:
  US09/566,742
• Time in Patent Office: 3,654 Days
• Field of Search: 349/156, 349/155, 349/130, 349/43, 349/88, 349/86, 349/191, 349/94, 349/123, 349/132, 349/129, 349/157, 349/152, 349/38, 349/47, 349/178
• US Class Current: 349/155
• CPC Class Codes: G02F 1/1337 Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
• CPC Class Codes: G02F 1/133707 Structures for producing distorted electric fields, e.g. bumps, protrusions, recesses, slits in pixel electrodes
• CPC Class Codes: G02F 1/13394 spacers regularly patterned on the cell subtrate, e.g. walls, pillars G02F1/133377 takes precedence
• CPC Class Codes: G02F 1/136204 Arrangements to prevent high voltage or static electricity failures
• CPC Class Codes: G02F 1/136213 Storage capacitors associated with the pixel electrode
• CPC Class Codes: G02F 1/1393 the birefringence of the liquid crystal being electrically controlled, e.g. ECB-, DAP-, HAN-, PI-LC cells G02F1/1396, G02F1/141 take precedence
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 27/124 with a particular composition, shape or layout of the wiring layers specially adapted to the circuit arrangement, e.g. scanning lines in LCD pixel circuits wiring structures per se H01L23/52
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details

Abstract

An electro-optical device typified by an active matrix type liquid crystal display device, is manufactured by cutting a rubbing process, and in addition, a reduction in the manufacturing cost and an improvement in the yield are realized by reducing the number of process steps to manufacture a TFT.

By forming a pixel TFT portion having a reverse stagger type n-channel TFT, and a storage capacitor, by performing three photolithography steps using three photomasks, and in addition, by having a uniform cell gap by forming wall-like spacers by performing one photolithography step, without performing a rubbing process, a multi-domain perpendicular orientation type liquid crystal display device having a wide viewing angle display, and in which a switching direction of the liquid crystal molecules is controlled, can be realized.

Claims

1. A liquid crystal display device having first and second substrates and a liquid crystal maintained between the first and second substrates, comprising:

a gate wiring over one of the first and second substrates;

an insulating film over said gate wiring;

an amorphous semiconductor film over said insulating film;

a source region and a drain region over said amorphous semiconductor film;

a source wiring over one of said source region and said drain region;

an electrode over the other of said source and drain regions;

a pixel electrode formed over said electrode; and

at least first and second gap retaining elements provided for maintaining a gap between the first and second substrates,

wherein each of the first and second gap retaining elements has a first end surface facing the first substrate and a second end surface facing the second substrate,

wherein the first end surface of the first gap retaining element is smaller than the second end surface of the first gap retaining element,

wherein the first end surface of the second gap retaining element is larger than the second end surface of the second gap retaining element, and

wherein said pixel electrode covers edges of said amorphous semiconductor film, and one of said source region and said drain region, and contacts with said insulating film.

2. The liquid crystal display device according to claim 1, wherein at least one of the substrates has an orientation film.

3. The liquid crystal display device according to claim 1, wherein at least one of said gap retaining elements has a constant taper angle.

4. The liquid crystal display device according to claim 3, wherein the taper angle of at least one of said gap retaining elements is from 75.0°

to 89.9°

, preferably from 82°

to 87°

.

5. The liquid crystal display device according to claim 1, wherein at least one of said gap retaining elements comprises:

an organic resin material comprising at least one material chosen from the group consisting of acrylics, polyimides, polyimide amines, and epoxies as its main constituent;

or

an inorganic material chosen from the group consisting of silicon oxide, silicon nitride, and silicon nitride oxide or a lamination film of such materials.

6. The liquid crystal display device according to claim 1, wherein the major axis direction of the liquid crystal molecules in the vicinity of the at least one side face of said gap retaining elements has strongly regulated orientation so as to be roughly parallel with respect to the side face.

7. The liquid crystal display device according to claim 1, wherein the liquid crystal has negative dielectric anisotropy.

8. The liquid crystal display device according to claim 1, wherein one end surface of said drain region or said source region roughly coincides with an end surface of said amorphous semiconductor film and an edge surface of said electrode.

9. The liquid crystal display device according to claim 1,

wherein one end surface of said drain region or said source region roughly coincides with an end surface of said amorphous semiconductor film and an end surface of said electrode, and

wherein another end surface of said drain region or said source region roughly coincides with an end surface of said pixel electrode and another end surface of said electrode.

10. The liquid crystal display device according to claim 1, wherein said source region and said drain region are made from an amorphous semiconductor film containing an impurity element which imparts n-type conductivity.

11. The liquid crystal display device according to claim 1, wherein said insulating film, said amorphous semiconductor film, said source region, and said drain region are formed in succession without exposure to the atmosphere.

12. The liquid crystal display device according to claim 1, wherein said insulating film, said amorphous semiconductor film, said source region, or said drain region is formed by sputtering.

13. The liquid crystal display device according to claim 1, wherein said insulating film, said amorphous semiconductor film, said source region, or said drain region is formed by plasma CVD.

14. The liquid crystal display device according to claim 1, wherein said gate wiring is formed from a film of an element selected from the group consisting of Al, Cu, Ti, Mo, W, Ta, Nd, and Cr, from an alloy film of said elements, or from a lamination film of said elements.

15. The liquid crystal display device according to claim 1, wherein said source region and said drain region are formed by the same mask as said amorphous semiconductor film and said electrode.

16. The liquid crystal display device according to claim 1, wherein said source region and said drain region are formed by the same mask as said source wiring.

17. The liquid crystal display device according to claim 1, wherein said source region and said drain region are formed by the same mask as said source wiring and said pixel electrode.

18. The liquid crystal display device according to claim 1, wherein said pixel electrode contacts said insulating film.

19. The liquid crystal display device according to claim 1, wherein in said amorphous semiconductor film, the film thickness in a region contacting said source region and said drain region is formed thicker than the film thickness in a region between the region contacting said source region and the region contacting said drain region.

20. The liquid crystal display device according to claim 1, wherein said liquid crystal display device is a personal computer, a video camera, a portable information terminal, a digital camera, a digital video disk player, or an electronic amusement device.

21. The liquid crystal display device according to claim 1, wherein a pre-tilt angle of the liquid crystal is controlled by at least one side face of said at least first and second gap retaining elements to orient the liquid crystal.

22. The liquid crystal display device according to claim 1, wherein the second gap retaining element is adjacent to the first gap retaining element.

23. A liquid crystal display device comprising:

a gate wiring comprising a conductive material over one of first and second substrates;

an insulating film over the gate wiring;

an amorphous semiconductor film over said insulating film;

a pair of impurity regions over the amorphous semiconductor film;

a source wiring over one of said pair of impurity regions;

an electrode over the other of said pair of impurity regions;

a pixel electrode over the electrode and extending over said insulating film;

at least first and second gap retaining elements provided for maintaining a gap between the first and second substrates;

wherein each of the first and second gap retaining elements has a first end surface facing the first substrate and a second end surface facing the second substrate,

wherein the first end surface of the first gap retaining element is smaller than the second end surface of the first gap retaining element, and

wherein the first end surface of the second gap retaining element is larger than the second end surface of the second gap retaining element,

a capacitor portion comprising;

a layer comprising the conductive material over the substrate;

the insulating film over the conductive material; and

the pixel electrode extending over said insulating film,

wherein the layer comprising the conductive material is covered by the pixel electrode through the insulating film;

wherein said pixel electrode covers edges of said amorphous semiconductor film, and one of said pair of impurity regions, and contacts with said insulating film, and

wherein said source wiring includes a first portion formed over one of said pair of impurity regions and a second portion extending in an orthogonal direction with respect to said layer comprising the conductive material.

24. The liquid crystal display device according to claim 23, wherein at least one of the substrates has an orientation film.

25. The liquid crystal display device according to claim 23, wherein at least one of said gap retaining elements has a constant taper angle.

26. The liquid crystal display device according to claim 25, wherein the taper angle of at least one of said gap retaining elements is from 75.0°

to 89.9°

, preferably from 82°

to 87°

.

27. The liquid crystal display device according to claim 23, wherein at least one of said gap retaining elements comprises:

an organic resin material comprising at least one material selected from the group consisting of acrylics, polyimides, polyimide amines, and epoxies as its main constituent;

or an inorganic material selected from the group consisting of silicon oxide, silicon nitride, and silicon nitride oxide or a lamination film of such materials.

28. The liquid crystal display device according to claim 23, wherein the major axis direction of the liquid crystal molecules in the vicinity of the at least one side face of said gap retaining elements has strongly regulated orientation so as to be roughly parallel with respect to the side face.

29. The liquid crystal display device according to claim 23, wherein the liquid crystal has negative dielectric anisotropy.

30. The liquid crystal display device according to claim 23, wherein said gate wiring is formed from a film of an element selected from the group consisting of Al, Cu, Ti, Mo, W, Ta, Nd, and Cr, from an alloy film of said elements, or from a lamination film of said elements.

31. The liquid crystal display device according to claim 23, wherein said liquid crystal display device is a personal computer, a video camera, a portable information terminal, a digital camera, a digital video disk player, or an electronic amusement device.

32. The liquid crystal display device according to claim 23, wherein a pre-tilt angle of the liquid crystal is controlled by at least one side face of said at least first and second gap retaining elements to orient the liquid crystal.

33. The liquid crystal display device according to claim 23, wherein the second gap retaining element is adjacent to the first gap retaining element.

34. A liquid crystal display device comprising:

a gate wiring comprising a first conductive material over one of first and second substrates;

an insulating film over the gate wiring;

an amorphous semiconductor film over said insulating film;

a pair of impurity regions over the amorphous semiconductor film;

a source wiring over one of said pair of impurity regions;

an electrode over the other of said, pair of impurity regions;

a pixel electrode comprising a second conductive material over the electrode, said second conductive material extending over said first conductive material;

at least first and second gap retaining elements over the pixel electrode, wherein the at least first and second gap retaining elements are provided for maintaining a gap between the first and second substrates;

wherein each of the first and second gap retaining elements has a first end surface facing the first substrate and a second end surface facing the second substrate,

wherein the first end surface of the first gap retaining element is smaller than the second end surface of the first gap retaining element, and

wherein the first end surface of the second gap retaining element is larger than the second end surface of the second gap retaining element,

a terminal portion comprising;

a first layer comprising the first conductive material over the substrate; and

a second layer extending over the first layer, the second layer comprising the second conductive material,

wherein said pixel electrode covers edges of the amorphous semiconductor film, and one of said impurity regions, and contacts with said insulating film.

35. The liquid crystal display device according to claim 34, wherein at least one of the substrates has an orientation film.

36. The liquid crystal display device according to claim 34, wherein at least one of said gap retaining elements has a constant taper angle.

37. The liquid crystal display device according to claim 36, wherein the taper angle of at least one of said gap retaining elements is from 75.0°

to 89.9°

, preferably from 82°

to 87°

.

38. The liquid crystal display device according to claim 34, wherein at least one of said gap retaining elements comprises:

an organic resin material comprising at least one material selected from the group consisting of acrylics, polyimides, polyimide amines, and epoxies as its main constituent;

or an inorganic material selected from the group consisting of silicon oxide, silicon nitride, and silicon nitride oxide or a lamination film of such materials.

39. The liquid crystal display device according to claim 34, wherein the major axis direction of the liquid crystal molecules in the vicinity of the at least one side face of said gap retaining elements has strongly regulated orientation so as to be roughly parallel with respect to the side face.

40. The liquid crystal display device according to claim 34, wherein the liquid crystal has negative dielectric anisotropy.

41. The liquid crystal display device according to claim 34, wherein said gate wiring is formed from a film of an element selected from the group consisting of Al, Cu, Ti, Mo, W, Ta, Nd, and Cr, from an alloy film of said elements, or from a lamination film of said elements.

42. The liquid crystal display device according to claim 34, wherein said liquid crystal display device is a personal computer, a video camera, a portable information terminal, a digital camera, a digital video disk player, or an electronic amusement device.

43. The liquid crystal display device according to claim 34, wherein a pre-tilt angle of the liquid crystal is controlled by at least one side face of said at least first and second gap retaining elements to orient the liquid crystal.

44. The liquid crystal display device according to claim 34, wherein the second gap retaining element is adjacent to the first gap retaining element.

45. A liquid crystal display device comprising:

a gate wiring comprising a first conductive material over one of first and second substrates;

an insulating film over the gate wiring;

an amorphous semiconductor film over said insulating film;

a pair of impurity regions over the amorphous semiconductor film;

a source wiring over one of said pair of impurity regions;

an electrode over the other of said pair of impurity regions;

a pixel electrode comprising a second conductive material over the electrode, said second conductive material extending over said insulating film and over said first conductive layer;

at least first and second gap retaining elements provided for maintaining a gap between the first and second substrates;

wherein each of the first and second gap retaining elements has a first end surface facing the first substrate and a second end surface facing the second substrate,

wherein the first end surface of the first gap retaining element is smaller than the second end surface of the first gap retaining element, and

wherein the first end surface of the second gap retaining element is larger than the second end surface of the second gap retaining element,

a capacitor portion comprising;

a layer comprising the first conductive material over the substrate;

the insulating film over the first conductive material; and

said second conductive material extending over the insulating film,

wherein the layer comprising the first conductive material is covered by the second conductive material through the insulating film;

wherein said source wiring includes a first portion formed over one of said pair of impurity regions and a second portion extending in an orthogonal direction with respect to said layer comprising the first conductive material,

a terminal portion comprising;

a first layer comprising the first conductive material over the substrate; and

a second layer extending over the first layer, the second layer comprising the second conductive material,

wherein said pixel electrode covers edges of the amorphous semiconductor film, and one of said impurity regions, and contacts with said insulating film.

46. The liquid crystal display device according to claim 45, wherein at least one of the substrates has an orientation film.

47. The liquid crystal display device according to claim 45, wherein at least one of said gap retaining elements has a constant taper angle.

48. The liquid crystal display device according to claim 47, wherein the taper angle of at least one of said gap retaining elements is from 75.0°

to 89.9°

, preferably from 82°

to 87°

.

49. The liquid crystal display device according to claim 45, wherein at least one of said gap retaining elements comprises:

an organic resin material comprising at least one material selected from the group consisting of acrylics, polyimides, polyimide amines, and epoxies as its main constituent;

or an inorganic material selected from the group consisting of silicon oxide, silicon nitride, and silicon nitride oxide or a lamination film of such materials.

50. The liquid crystal display device according to claim 45, wherein the major axis direction of the liquid crystal molecules in the vicinity of the at least one side face of said gap retaining elements has strongly regulated orientation so as to be roughly parallel with respect to the side face.

51. The liquid crystal display device according to claim 45, wherein the liquid crystal has negative dielectric anisotropy.

52. The liquid crystal display device according to claim 45, wherein said gate wiring is formed from a film of an element selected from the group consisting of Al, Cu, Ti, Mo, W, Ta, Nd, and Cr, from an alloy film of said elements, or from a lamination film of said elements.

53. The liquid crystal display device according to claim 45, wherein said liquid crystal display device is a personal computer, a video camera, a portable information terminal, a digital camera, a digital video disk player, or an electronic amusement device.

54. The liquid crystal display device according to claim 45, wherein a pre-tilt angle of the liquid crystal is controlled by at least one side face of said at least first and second gap retaining elements to orient the liquid crystal.

55. The liquid crystal display device according to claim 45, wherein the second gap retaining element is adjacent to the first gap retaining element.

56. A liquid crystal display device comprising:

a gate wiring over one of first and second substrates;

an insulating film over the gate wiring;

an amorphous semiconductor film over said insulating film;

a pair of impurity regions over the amorphous semiconductor film;

a source wiring and an electrode over the pair of impurity regions;

a pixel electrode over the electrode; and

at least first and second gap retaining elements over the pixel electrode,

wherein each of the first and second gap retaining elements has a first end surface facing the first substrate and a second end surface facing the second substrate,

wherein the first end surface of the first gap retaining element is smaller than the second end surface of the first gap retaining element,

wherein the first end surface of the second gap retaining element is larger than the second end surface of the second gap retaining element, and

wherein said pixel electrode covers edges of the amorphous semiconductor film, and one of said pair of impurity regions, and contacts with said insulating film.

57. The liquid crystal display device according to claim 56, wherein at least one of the substrates has an orientation film.

58. The liquid crystal display device according to claim 56, wherein at least one of said gap retaining elements has a constant taper angle.

59. The liquid crystal display device according to claim 58, wherein the taper angle of at least one of said gap retaining elements is from 75.0°

to 89.9°

, preferably from 82°

to 87°

.

60. The liquid crystal display device according to claim 56, wherein at least one of said gap retaining elements comprises:

an organic resin material comprising at least one material selected from the group consisting of acrylics, polyimides, polyimide amines, and epoxies as its main constituent;

or an inorganic material selected from the group consisting of silicon oxide, silicon nitride, and silicon nitride oxide or a lamination film of such materials.

61. The liquid crystal display device according to claim 56, wherein the major axis direction of the liquid crystal molecules in the vicinity of the at least one side face of said gap retaining elements has strongly regulated orientation so as to be roughly parallel with respect to the side face.

62. The liquid crystal display device according to claim 56, wherein the liquid crystal has negative dielectric anisotropy.

63. The liquid crystal display device according to claim 56, wherein said gate wiring is formed from a film of an element selected from the group consisting of Al, Cu, Ti, Mo, W, Ta, Nd, and Cr, from an alloy film of said elements, or from a lamination film of said elements.

64. The liquid crystal display device according to claim 56, wherein said liquid crystal display device is a personal computer, a video camera, a portable information terminal, a digital camera, a digital video disk player, or an electronic amusement device.

65. The liquid crystal display device according to claim 56, wherein a pre-tilt angle of the liquid crystal is controlled by at least one side face of said at least first and second gap retaining elements to orient the liquid crystal.

66. The liquid crystal display device according to claim 56, wherein the second gap retaining element is adjacent to the first gap retaining element.