Display device and method of fabricating the display device

• US 6,739,931 B2
• Filed: 09/17/2001
• Issued: 05/25/2004
• Est. Priority Date: 09/18/2000
• Status: Expired due to Term

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Suzawa, Hideomi, Yamazaki, Shunpei, Uehara, Ichiro
• Primary Examiner(s): Ramsey, Kenneth J.
• Application Number:
  US09/953,765
• Publication Number:
  US 20020074936A1
• Time in Patent Office: 981 Days
• Field of Search: 216/41-49, 445/24, 430/217, 430/317
• US Class Current: 445/24
• 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 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.

2. A method of fabricating a display device according to claim 1, wherein said mask is a resist film.

3. A method of fabricating a display device according to claim 1, 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.

4. A method of fabricating a display device according to claim 1, 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.

5. 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.

6. A method of fabricating a display device according to claim 5, wherein said mask is a resist film.

7. A method of fabricating a display device according to claim 5, 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.

8. 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.

9. A method of fabricating a display device according to claim 8, wherein said insulating film comprises an organic material.

10. A method of fabricating a display device according to claim 8, wherein said mask is a resist film.

11. A method of fabricating a display device according to claim 8, 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.

12. 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.

13. A method of fabricating a display device according to claim 12, wherein said insulating film comprises an organic material.

14. A method of fabricating a display device according to claim 12, wherein said mask is a resist film.

15. A method of fabricating a display device according to claim 12, 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.

16. 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;

heat treating said organic film; and

forming an electroluminescence film on said organic film and said electrode.

17. A method of fabricating a display device according to claim 16, wherein said mask is a resist film.

18. A method of fabricating a display device according to claim 16, 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.

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

forming an organic film on an electrode;

heating said organic film;

forming a mask on said organic film;

performing exposure of said mask;

removing said mask;

etching said organic film isotropically; and

forming an electroluminescence film on said organic film and said electrode.

20. A method of fabricating a display device according to claim 19, wherein said mask is a resist film.

21. A method of fabricating a display device according to claim 19, 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.

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

forming an organic film on an electrode;

heating said organic film;

forming a mask on said organic film;

performing exposure of said mask by irradiating an ultraviolet ray through a photomask;

removing said mask;

etching said organic film isotropically; and

forming an electroluminescence film on said organic film and said electrode.

23. A method of fabricating a display device according to claim 22, wherein said mask is a resist film.

24. A method of fabricating a display device according to claim 22, wherein in said performing exposure step, diffraction of said ultraviolet ray passed through said photomask is caused.

25. A method of fabricating a display device according to claim 22, 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.

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

forming a thin film transistor over a substrate;

forming an insulating film over said thin film transistor;

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;

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.

27. A method of fabricating a display device according to claim 26, wherein said insulating film comprises an organic material.

28. A method of fabricating a display device according to claim 26, wherein said mask is a resist film.

29. A method of fabricating a display device according to claim 26, 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.