DISPLAY DEVICE AND MANUFACTURING METHOD THEREOF

• US 20070146592A1
• Filed: 12/21/2006
• Published: 06/28/2007
• 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
• Granted Patent: US 7,821,613 B2
• Time in Patent Office: Days
• 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;

a transparent electrode which is electrically connected to the transistor;

a reflective electrode which is electrically connected to the transparent electrode; and

a storage capacitor which is electrically connected to the transistor,

wherein at least a part of the storage capacitor is formed below the reflective electrode; and

wherein an entire under surface of the reflective electrode is in contact with a top surface of the transparent electrode.

6. The display device according to claim 1, wherein a liquid crystal layer is provided between the reflective electrode and an opposite electrode.

11. An electronic apparatus comprising the display device according to claim 1.

2. A display device comprising:

a transistor;

a transparent electrode which is electrically connected to the transistor; and

a reflective electrode which is electrically connected to the transparent electrode,

wherein at least one of the transparent electrode and the reflective electrode comprises a slit; and

wherein an entire under surface of the reflective electrode is in contact with a top surface of the transparent electrode.

7. The display device according to claim 2, wherein a liquid crystal layer is provided between the reflective electrode and an opposite electrode.

12. An electronic apparatus comprising the display device according to claim 2.

3. A display device comprising:

a transistor;

a transparent electrode which is electrically connected to the transistor;

a reflective electrode which is electrically connected to the transparent electrode; and

a storage capacitor which is electrically connected to the transistor,

wherein at least one of the transparent electrode and the reflective electrode comprises a slit;

wherein at least a part of the storage capacitor is formed below the reflective electrode; and

wherein an entire under surface of the reflective electrode is in contact with a top surface of the transparent electrode.

8. The display device according to claim 3, wherein a liquid crystal layer is provided between the reflective electrode and an opposite electrode.

13. An electronic apparatus comprising the display device according to claim 3.

4. A display device comprising:

a transistor;

a transparent electrode which is electrically connected to the transistor;

a reflective electrode which is electrically connected to the transparent electrode; and

a storage capacitor which is electrically connected to the transistor,

wherein at least a part of the storage capacitor is formed below the reflective electrode;

wherein at least a part of the transistor is formed below the reflective electrode; and

wherein an entire under surface of the reflective electrode is in contact with a top surface of the transparent electrode.

9. The display device according to claim 4, wherein a liquid crystal layer is provided between the reflective electrode and an opposite electrode.

14. An electronic apparatus comprising the display device according to claim 4.

5. A display device comprising:

a transistor; and

a pixel electrode which is electrically connected to the transistor,

wherein the pixel electrode comprises a transparent electrode and a reflective electrode;

wherein an entire under surface of the reflective electrode is in contact with a top surface of the transparent electrode; and

wherein a film thickness of the transparent electrode in a region in contact with the reflective electrode is thicker than a film thickness of the transparent electrode in a region not in contact with the reflective electrode.

10. The display device according to claim 5, wherein a liquid crystal layer is provided between the reflective electrode and an opposite electrode.

15. An electronic apparatus comprising the display device according to claim 5.

16. A manufacturing method of a display device, comprising the steps of:

forming a transistor over a substrate;

forming an insulating film over the transistor;

forming a transparent conductive film over the insulating film;

forming a reflective conductive film over the transparent conductive film;

forming a resist pattern which comprises a region having a thick film thickness and a region having a thinner film thickness than the region over the reflective conductive film by using a light exposure mask which comprises a semi-transmission portion; and

forming a transparent electrode formed of the transparent conductive film and a reflective electrode formed of the reflective conductive film by using the resist pattern.

17. A manufacturing method of a display device, comprising the steps of:

forming a transistor over a substrate;

forming an insulating film over the transistor;

forming a transparent conductive film over the insulating film;

forming a reflective conductive film over the transparent conductive film;

forming a resist pattern which comprises a region having a thick film thickness and a region having a thinner film thickness than the region over the reflective conductive film by using a light exposure mask which comprises a semi-transmission portion;

etching the reflective conductive film and the transparent conductive film by using the resist pattern;

removing a part of the resist pattern; and

etching the reflective conductive film by using the resist pattern a part of which is removed.