Display device and manufacturing method thereof

• US 8,634,044 B2
• Filed: 03/24/2010
• Issued: 01/21/2014
• Est. Priority Date: 12/28/2005
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Kimura, Hajime
• Primary Examiner(s): Nguyen, Dung
• Assistant Examiner(s): DUONG, TAI V
• Application Number:
  US12/730,566
• Publication Number:
  US 20100177269A1
• Time in Patent Office: 1,399 Days
• Field of Search: 349/42, 349/43, 349/113, 349/114, 349/122, 349/138, 257/43, 257/59, 257/72, 257/E29.111, 257/E29.242, 345/92
• US Class Current: 349/114
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G02F 1/1333 Constructional arrangements; Manufacturing methodsG02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/133345 Insulating layers G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/133371 Cells with varying thickness of the liquid crystal layer
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/136231 for reducing the number of lithographic steps
• CPC Class Codes: G02F 1/136286 Wiring, e.g. gate line, drain line
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G02F 2202/36 Micro- or nanomaterials

Abstract

In a semi-transmission liquid crystal display device, two resist masks are required to form a reflective electrode and a transparent electrode; therefore, cost is high. A transparent electrode and a reflective electrode which function as a pixel electrode are stacked. A resist pattern which includes a region having a thick film thickness and a region having a thinner film thickness than the aforementioned region is formed over the reflective electrode by using a light exposure mask which includes a semi-transmission portion. The reflective electrode and the transparent electrode are formed by using the resist pattern. Therefore, the reflective electrode and the transparent electrode can be formed by using one resist mask.

Claims

1. A display device comprising:

a transistor over a substrate, the transistor comprising a semiconductor film comprising a compound semiconductor;

a first insulating film over the semiconductor film;

a second insulating film over the first insulating film;

a transparent electrode over the second insulating film, the transparent electrode comprising a slit; and

a reflective electrode over the transparent electrode, the reflective electrode comprising a slit,

wherein the transparent electrode and the reflective electrode overlap with each other, and

wherein the slit of the transparent electrode and the slit of the reflective electrode overlap with each other.

2. The display device according to claim 1, wherein the compound semiconductor comprises In and Zn.

3. The display device according to claim 1, wherein the transistor has a top gate structure.

4. The display device according to claim 1, wherein a portion of the first insulating film is configured to transmit a light passed through the substrate.

5. The display device according to claim 1, wherein the reflective electrode is electrically connected to the transparent electrode.

6. The display device according to claim 1, wherein the first insulating film is a silicon oxide film.

7. The display device according to claim 1, wherein the second insulating film comprises acrylic.

8. The display device according to claim 1, wherein the transparent electrode comprises an indium tin oxide.

9. The display device according to claim 1, wherein the reflective electrode comprises Al and Ti.

10. An electronic book comprising a display portion into which the display device according to claim 1 is incorporated.

11. A display device comprising:

a transistor over a substrate, the transistor comprising a semiconductor film comprising a compound semiconductor;

a first insulating film over the semiconductor film;

a second insulating film over the first insulating film, the second insulating film comprising a uneven surface;

a transparent electrode over the second insulating film, the transparent electrode comprising a slit; and

a reflective electrode over the transparent electrode so that the reflective electrode is uneven due to the uneven surface of the second insulating film, the reflective electrode comprising a slit,

wherein the transparent electrode and the reflective electrode overlap with each other, and

wherein the slit of the transparent electrode and the slit of the reflective electrode overlap with each other.

12. The display device according to claim 11, wherein the compound semiconductor comprises In and Zn.

13. The display device according to claim 11, wherein the transistor has a top gate structure.

14. The display device according to claim 11, wherein a portion of the first insulating film is configured to transmit a light passed through the substrate.

15. The display device according to claim 11, wherein the reflective electrode is electrically connected to the transparent electrode.

16. The display device according to claim 11, wherein the first insulating film is a silicon oxide film.

17. The display device according to claim 11, wherein the second insulating film comprises acrylic.

18. The display device according to claim 11, wherein the transparent electrode comprises an indium tin oxide.

19. The display device according to claim 11, wherein the reflective electrode comprises Al and Ti.

20. An electronic book comprising a display portion into which the display device according to claim 11 is incorporated.

21. A display device comprising:

a transistor over a substrate, the transistor comprising a semiconductor film comprising InGaZnO;

a first insulating film over the semiconductor film;

a second insulating film over the first insulating film;

a transparent electrode over the second insulating film, the transparent electrode comprising a slit; and

a reflective electrode over the transparent electrode, the reflective electrode comprising a slit,

wherein the transparent electrode and the reflective electrode overlap with each other, and

wherein the slit of the transparent electrode and the slit of the reflective electrode overlap with each other.

22. The display device according to claim 21, wherein InGaZnO is a-InGaZnO.

23. The display device according to claim 21, wherein the transistor has a top gate structure.

24. The display device according to claim 21, wherein a portion of the first insulating film is configured to transmit a light passed through the substrate.

25. The display device according to claim 21, wherein the reflective electrode is electrically connected to the transparent electrode.

26. The display device according to claim 21, wherein the first insulating film is a silicon oxide film.

27. The display device according to claim 21, wherein the second insulating film comprises acrylic.

28. The display device according to claim 21, wherein the transparent electrode comprises an indium tin oxide.

29. The display device according to claim 21, wherein the reflective electrode comprises Al and Ti.

30. An electronic book comprising a display portion into which the display device according to claim 21 is incorporated.

31. A display device comprising:

a transistor over a substrate, the transistor comprising a semiconductor film comprising InGaZnO;

a first insulating film over the semiconductor film;

a second insulating film over the first insulating film, the second insulating film comprising a uneven surface;

a transparent electrode over the second insulating film, the transparent electrode comprising a slit; and

a reflective electrode over the transparent electrode so that the reflective electrode is uneven due to the uneven surface of the second insulating film, the reflective electrode comprising a slit,

wherein the transparent electrode and the reflective electrode overlap with each other, and

wherein the slit of the transparent electrode and the slit of the reflective electrode overlap with each other.

32. The display device according to claim 31, wherein InGaZnO is a-InGaZnO.

33. The display device according to claim 31, wherein the transistor has a top gate structure.

34. The display device according to claim 31, wherein a portion of the first insulating film is configured to transmit a light passed through the substrate.

35. The display device according to claim 31, wherein the reflective electrode is electrically connected to the transparent electrode.

36. The display device according to claim 31, wherein the first insulating film is a silicon oxide film.

37. The display device according to claim 31, wherein the second insulating film comprises acrylic.

38. The display device according to claim 31, wherein the transparent electrode comprises an indium tin oxide.

39. The display device according to claim 31, wherein the reflective electrode comprises Al and Ti.

40. An electronic book comprising a display portion into which the display device according to claim 31 is incorporated.