Display device and method of fabricating the display device

• US 20040195964A1
• Filed: 04/20/2004
• Published: 10/07/2004
• Est. Priority Date: 09/18/2000
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Suzawa, Hideomi, Yamazaki, Shunpei, Uehara, Ichiro
• Granted Patent: US 7,514,868 B2
• Time in Patent Office: Days
• US Class Current: 313/504
• CPC Class Codes: H01L 27/1214 comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• 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 27/1248 with a particular composition or shape of the interlayer dielectric specially adapted to the circuit arrangement
• CPC Class Codes: H10K 59/122 Pixel-defining structures or layers, e.g. banks
• CPC Class Codes: H10K 59/40 OLEDs integrated with touch screens
• CPC Class Codes: Y10S 428/917 Electroluminescent

Abstract

In an EL element having an anode, an insulating film (bump) formed on the anode, and an EL film and a cathode formed on the insulating film, each of a bottom end portion and a top end portion of the insulating film is formed so as to have a curved surface. The taper angle of a central portion of the insulating film is set within the range from 35° to 70°, thereby preventing the gradient of the film forming surface on which the EL film and the cathode are to be formed from being abruptly changed. On the thus-formed film forming surface, the EL film and the cathode can be formed so as to be uniform in thickness, so that occurrence of discontinuity in each of EL film and the cathode is prevented.

Claims

1. A display device comprising:

a first electrode on an insulating surface;

an electroluminescence film on said first electrode;

a second electrode on said electroluminescence film; and

a bump selectively formed for covering an end portion of said first electrode,

wherein said bump has a bottom end portion contacting with an upper surface of said electrode and a top end portion connecting continuously to a flat upper surface of said bump,

wherein a surface of said bottom end portion is rounded, and a surface of said top end portion is rounded.

2. A display device according to claim 1, wherein an angle between a tangent of said bump and the upper surface of said electrode changes continuously from said bottom end portion to said top end portion, said angle being within 0°

to 70°

.

3. A display device according to claim 1, wherein said bump comprises an organic material.

4. A display device according to claim 1, wherein the thickness of said bump is within 1.0 to 3.0 μ

m.

5. A display device according to claim 1, wherein said electroliminescence film comprises an organic material.

6. A display device according to claim 1, wherein said second electrode is formed by superposed on said bottom end portion and said top end portion.

7. A display device according to claim 1, wherein each of said electrodes is one of an anode and a cathode.

8. An electronic equipment comprising said display device according to claim 1, wherein said electronic equipment is selected the group consisting of a personal computer, a video camera, a portable information terminal, a digital camera, a digital video disc player, and an electronic game machine.

9. A display device comprising:

a first electrode on an insulating surface;

an electroluminescence film on said first electrode;

a second electrode on said electroluminescence film; and

a bump selectively formed for covering an end portion of said first electrode,

wherein said bump has a bottom end portion contacting with an upper surface of said electrode, a top end portion connecting continuously to a flat upper surface of said bump, and a central portion between said bottom end portion and said top end portion,

wherein each of said bottom end portion and a surface of said top end portion is rounded, and a tangent of said central portion has a taper angle of 35°

to 70°

with respect to said upper surface of said electrode.

10. A display device according to claim 9, wherein an angle between a tangent of said bump and the upper surface of said electrode changes continuously from said bottom end portion to said top end portion, said angle being within o0 to 70°

.

11. A display device according to claim 9, wherein said bump comprises an organic material.

12. A display device according to claim 9, wherein the thickness of said bump is within 1.0 to 3.0 μ

m.

13. A display device according to claim 9, wherein said electroliminescence film comprises an organic material.

14. A display device according to claim 9, wherein said second electrode is formed by superposed on said bottom end portion and said top end portion.

15. A display device according to claim 9, wherein each of said electrodes is one of an anode and a cathode.

16. An electronic equipment comprising said display device according to claim 9, wherein said electronic equipment is selected the group consisting of a personal computer, a video camera, a portable information terminal, a digital camera, a digital video disc player, and an electronic game machine.

17. A display device comprising:

a first electrode on an insulating surface;

an electroluminescence film on said first electrode;

a second electrode on said electroluminescence film; and

a bump selectively formed for covering an end portion of said first electrode,

wherein said bump has a bottom end portion contacting with an upper surface of said electrode and a top end portion connecting continuously to a flat upper surface of said bump,

wherein said bottom end portion has a curved surface having a first radius of a curvature and a center of curvature located above said first electrode, and said top end portion has a curved surface having a second radius of a curvature and a center of curvature located inside said bump.

18. A display device according to claim 17, wherein an angle between a tangent of said bump and the upper surface of said electrode changes continuously from said bottom end portion to said top end portion, said angle being within 0°

to 70°

.

19. A display device according to claim 17, wherein said bump comprises an organic material.

20. A display device according to claim 17, wherein the thickness of said bump is within 1.0 to 3.0 μ

m.

21. A display device according to claim 17, wherein said electroliminescence film comprises an organic material.

22. A display device according to claim 17, wherein said second electrode is formed by superposed on said bottom end portion and said top end portion.

23. A display device according to claim 17, wherein each of said electrodes is one of an anode and a cathode.

24. A display device according to claim 17, wherein each of said first radius of curvature and said second radius of curvature is within 0.2 to 3.0 μ

m.

25. An electronic equipment comprising said display device according to claim 17, wherein said electronic equipment is selected the group consisting of a personal computer, a video camera, a portable information terminal, a digital camera, a digital video disc player, and an electronic game machine.

26. A display device comprising:

a first electrode on an insulating surface;

an electroluminescence film on said first electrode;

a second electrode on said electroluminescence film; and

a bump selectively formed for covering an end portion of said first electrode.

wherein said bump has a bottom end portion contacting with an upper surface of said electrode, a top end portion connecting continuously to a flat upper surface of said bump, and a central portion between said bottom end portion and said top end portion,

wherein said bottom end portion has a curved surface having a first radius of a curvature and a center of curvature located above said first electrode, said top end portion has a curved surface having a second radius of a curvature and a center of curvature located inside said bump, and a tangent of said central portion has a taper angle of 35°

to 70°

with respect to said upper surface of said electrode.

27. A display device according to claim 26, wherein an angle between a tangent of bump and the upper surface of said electrode changes continuously from said bottom end portion to said top end portion, said angle being within 0°

to 70°

.

28. A display device according to claim 26, wherein said bump comprises an organic material.

29. A display device according to claim 26, wherein the thickness of said bump is within 1.0 to 3.0 μ

m.

30. A display device according to claim 26, wherein said electroliminescence film comprises an organic material.

31. A display device according to claim 26, wherein said second electrode is formed by superposed on said bottom end portion and said top end portion.

32. A display device according to claim 26, wherein each of said electrodes is one of an anode and a cathode.

33. A display device according to claim 26, wherein each of said first radius of curvature and said second radius of curvature is within 0.2 to 3.0 μ

m.

34. An electronic equipment comprising said display device according to claim 26, wherein said electronic equipment is selected the group consisting of a personal computer, a video camera, a portable information terminal, a digital camera, a digital video disc player, and an electronic game machine.

35. A display device comprising:

a first electrode on an insulating surface;

an electroluminescence film on said first electrode;

a second electrode on said electroluminescence film; and

a bump selectively formed for covering an end portion of said electrode, said bump having a bottom end portion contacting with an upper surface of said electrode and a top end portion connecting continuously to a flat upper surface of said bump,

wherein an angle between a tangent of said bump and the upper surface of said electrode changes continuously from said bottom end portion to said top end portion, said angle being within 0°

to 70°

.

36. A display device according to claim 35, wherein said bump comprises an organic material.

37. A display device according to claim 35, wherein the thickness of said bump is within 1.0 to 3.0 μ

m.

38. A display device according to claim 35, wherein said electroliminescence film comprises an organic material.

39. A display device according to claim 35, wherein said second electrode is formed by superposed on said bottom end portion and said top end portion.

40. A display device according to claim 35, wherein each of said electrodes is one of an anode and a cathode.

41. An electronic equipment comprising said display device according to claim 35, wherein said electronic equipment is selected the group consisting of a personal computer, a video camera, a portable information terminal, a digital camera, a digital video disc player, and an electronic game machine.

42. A display device comprising:

a first electrode on an insulating surface;

an electroluminescence film on said first electrode;

a second electrode on said electroluminescence film; and

a bump selectively formed for covering an end portion of said electrode,

wherein said bump has a bottom end portion contacting with an upper surface of said electrode and a top end portion connecting continuously to a flat upper surface of said bump,

wherein said bottom end portion has an elliptic or circular surface having a center located above said first electrode, and said top end portion has an elliptic or circular surface having a center located inside said bump.

43. A display device according to claim 42, wherein an angle between a tangent of said bump and the upper surface of said electrode changes continuously from said bottom end portion to said top end portion, said angle being within 0°

to 70°

.

44. A display device according to claim 42, wherein said bump comprises an organic material.

45. A display device according to claim 42, wherein the thickness of said bump is within 1.0 to 3.0 μ

m.

46. A display device according to claim 42, wherein said electroliminescence film comprises an organic material.

47. A display device according to claim 42, wherein said second electrode is formed by superposed on said bottom end portion and said top end portion.

48. A display device according to claim 42, wherein each of said electrodes is one of an anode and a cathode.

49. An electronic equipment comprising said display device according to claim 42, wherein said electronic equipment is selected the group consisting of a personal computer, a video camera, a portable information terminal, a digital camera, a digital video disc player, and an electronic game machine.

50. A method of fabricating a display device, comprising the steps of:

forming an electrode;

forming an insulating film on said electrode;

patterning a mask on said insulating film;

shaping said insulating film by etching using at least a first reactive gas and a second reactive gas;

removing said mask; and

forming an electroluminescence film on said insulating film,

wherein said etching comprises a first etching step in which the flow rate of said first reactive gas to said second reactive gas is increased with time, a second etching step in which the flow rates of said first reactive gas and said second reactive gas is constant, and a third etching step in which the flow rate of said first reactive gas to said second reactive gas is reduced with time.

51. A method of fabricating a display device according to claim 50, wherein said mask is a resist film.

52. A method of fabricating a display device according to claim 50, wherein said first reactive gas is CF₄, said second reactive gas is O₂, and said insulating film is formed of an acrylic resin film or a polyimide resin film.

53. A method of fabricating a display device according to claim 50, wherein said display device is incorporated an electronic equipment selected from the group consisting of a personal computer, a video camera, a portable information terminal, a digital camera, a digital video disc player, and an electronic game machine.

54. A method of fabricating a display device, comprising:

applying an organic film having polyamic acid as a main component on an electrode;

heat-treating said organic film at a temperature within the range from 50 to 150°

C;

forming a mask on said organic film;

performing exposure of said mask;

selectively dissolving portions of said mask and said organic film in a basic developer;

removing said mask;

heat-treating said organic film at a temperature within the range from 180 to 350°

C. to form a polyimide resin film; and

forming an electroluminescence film on said polyimide resin film.

55. A method of fabricating a display device according to claim 54, wherein said mask is a resist film.

56. A method of fabricating a display device according to claim 54, wherein said display device is incorporated an electronic equipment selected from the group consisting of a personal computer, a video camera, a portable information terminal, a digital camera, a digital video disc player, and an electronic game machine.

57. A method of fabricating a display device, comprising the steps of:

forming an electrode on an insulating surface;

forming an insulating film over said first electrode;

forming a mask on said insulating film;

selectively etching a portion of said insulating film in accordance with said mask by using at least first and second reactive gases, thereby, exposing a portion of said electrode from said insulating film, said first reactive gas comprising a fluoride gas,

wherein a flow rate of said first reactive gas with respect to said second reactive gas is kept constant during a certain period, and said flow rate is decreased during the next period.

58. A method of fabricating a display device according to claim 57, wherein said insulating film comprises an organic material.

59. A method of fabricating a display device according to claim 57, wherein said mask is a resist film.

60. A method of fabricating a display device according to claim 57, wherein said display device is incorporated an electronic equipment selected from the group consisting of a personal computer, a video camera, a portable information terminal, a digital camera, a digital video disc player, and an electronic game machine.

61. A method of fabricating a display device, comprising the steps of:

forming an electrode on an insulating surface;

forming an insulating film over said first electrode;

forming a mask on said insulating film;

selectively etching a portion of said insulating film in accordance with said mask by using at least first and second reactive gases, thereby, exposing a portion of said electrode from said insulating film, said first reactive gas comprising a fluoride gas,

wherein a flow rate of said first reactive gas with respect to said second reactive gas is increased during a first period of the etching, said flow rate is kept constant during a second period of the etching after said first period, and said flow rate is decreased during a third period of the etching after said second period.

62. A method of fabricating a display device according to claim 61, wherein said insulating film comprises an organic material.

63. A method of fabricating a display device according to claim 61, wherein said mask is a resist film.

64. A method of fabricating a display device according to claim 61, wherein said display device is incorporated an electronic equipment selected from the group consisting of a personal computer, a video camera, a portable information terminal, a digital camera, a digital video disc player, and an electronic game machine.

65. A method of fabricating a display device, comprising the steps of:

forming an organic film on an electrode;

heat treating said organic film;

forming a mask on said organic film;

performing exposure of said mask;

immersing said mask and said organic film in a basic developer;

removing said mask; and

heat treating said organic film.

66. A method of fabricating a display device according to claim 65, wherein said mask is a resist film.

67. A method of fabricating a display device according to claim 65, wherein said display device is incorporated an electronic equipment selected from the group consisting of a personal computer, a video camera, a portable information terminal, a digital camera, a digital video disc player, and an electronic game machine.