Liquid crystal display device and method for manufacturing the same

• US 8,558,960 B2
• Filed: 09/07/2011
• Issued: 10/15/2013
• Est. Priority Date: 09/13/2010
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei, Hatano, Kaoru
• Primary Examiner(s): DUDEK, JAMES A
• Application Number:
  US13/227,092
• Publication Number:
  US 20120062814A1
• Time in Patent Office: 769 Days
• Field of Search: 349/43, 349/47
• US Class Current: 349/43
• CPC Class Codes: G02F 1/1333 Constructional arrangements; Manufacturing methodsG02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/1343 Electrodes reflective electrodes G02F1/133553
• CPC Class Codes: G02F 1/136213 Storage capacitors associated with the pixel electrode
• CPC Class Codes: G02F 1/136227 Through-hole connection of the pixel electrode to the active element through an insulation layer
• CPC Class Codes: G02F 1/136231 for reducing the number of lithographic steps
• CPC Class Codes: G02F 2201/50 Protective arrangements
• CPC Class Codes: H01L 27/1225 with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO
• 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 27/1259 Multistep manufacturing methods
• CPC Class Codes: H01L 29/24 including, apart from doping materials or other impurities, only semiconductor materials not provided for in groups H01L29/16, H01L29/18, H01L29/20, H01L29/22 including organic materials H10K99/00
• CPC Class Codes: H01L 29/78618 characterised by the drain or the source properties, e.g. the doping structure, the composition, the sectional shape or the contact structure silicide contacts, electrodes in general H01L29/458
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate
• CPC Class Codes: H01L 29/78696 characterised by the structure of the channel, e.g. multichannel, transverse or longitudinal shape, length or width, doping structure, or the overlap or alignment between the channel and the gate, the source or the drain, or the contacting structure of the channel H01L29/78612 takes precedence; transistors having a drain offset region or a lightly doped drain [LDD] H01L29/78621

Abstract

Provided is a method to manufacture a liquid crystal display device in which a contact hole for the electrical connection of the pixel electrode and one of the source and drain electrode of a transistor and a contact hole for the processing of a semiconductor layer are formed simultaneously. The method contributes to the reduction of a photography step. The transistor includes an oxide semiconductor layer where a channel formation region is formed.

Claims

1. A liquid crystal display device comprising a pixel over a substrate, the pixel comprising:

a thin film transistor comprising;

an oxide semiconductor layer; and

a source electrode and a drain electrode which are electrically connected to the oxide semiconductor layer; and

a liquid crystal element comprising;

a pixel electrode electrically connected to one of the source electrode and the drain electrode; and

a liquid crystal material over the pixel electrode,

wherein the pixel electrode is in direct contact with a side surface of the oxide semiconductor layer in the pixel.

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

wherein the thin film transistor further comprises a gate electrode and a gate insulating layer which is provided between the gate electrode and the oxide semiconductor layer, and

wherein the pixel electrode is in direct contact with a side surface of the gate insulating layer in the pixel.

3. The liquid crystal display device according to claim 2,

wherein the thin film transistor further comprises an insulating layer over the source electrode and the drain electrode,

wherein the insulating layer is in contact with the oxide semiconductor layer in a first region overlapping with the gate electrode, and

wherein the electrical contact of the pixel electrode with the one of the source electrode and the drain electrode is performed in a contact hole formed in the insulating layer.

4. The liquid crystal display device according to claim 1, further comprising a base layer between the thin film transistor and the substrate,

wherein the pixel electrode is in direct contact with the base layer in the pixel.

5. The liquid crystal display device according to claim 1, wherein the oxide semiconductor layer comprises an element selected from gallium and indium.

13. The liquid crystal display device according to claim 1, wherein the substrate is flexible.

15. The liquid crystal display device according to claim 3, wherein the insulating layer is further in direct contact with the oxide semiconductor layer in a second region which does not overlap with the gate electrode.

6. A liquid crystal display device comprising a pixel over a substrate, the pixel comprising:

a thin film transistor comprising;

an oxide semiconductor layer; and

a source electrode and a drain electrode which are electrically connected to the oxide semiconductor layer;

a liquid crystal element comprising;

a pixel electrode electrically connected to one of the source electrode and the drain electrode; and

a liquid crystal material over the pixel electrode; and

a capacitor comprising;

a capacitor wiring; and

a dielectric layer over the capacitor wiring,

wherein the pixel electrode extends over the dielectric layer so that the pixel electrode overlaps with the capacitor wiring with the dielectric layer interposed therebetween, and

wherein the pixel electrode is in direct contact with a side surface of the oxide semiconductor layer in the pixel.

7. The liquid crystal display device according to claim 6,

wherein the thin film transistor further comprises a gate electrode and a gate insulating layer which is provided between the gate electrode and the oxide semiconductor layer, and

wherein the pixel electrode is in direct contact with a side surface of the gate insulating layer in the pixel.

8. The liquid crystal display device according to claim 7,

wherein the thin film transistor further comprises an insulating layer over the source electrode and the drain electrode,

wherein the insulating layer is in contact with the oxide semiconductor layer in a region overlapping with the gate electrode, and

wherein the electrical contact of the pixel electrode with the one of the source electrode and the drain electrode is performed in a contact hole formed in the insulating layer.

9. The liquid crystal display device according to claim 6, further comprising a base layer between the thin film transistor and the substrate,

wherein the pixel electrode is in direct contact with the base layer in the pixel.

10. The liquid crystal display device according to claim 6, wherein the pixel electrode is in direct contact with a side surface of the dielectric layer.

11. The liquid crystal display device according to claim 6,

wherein the capacitor further comprises an electrode between the pixel electrode and the capacitor wiring, and

wherein the electrode is electrically connected to the pixel electrode.

12. The liquid crystal display device according to claim 6, wherein the oxide semiconductor layer comprises an element selected from gallium and indium.

14. The liquid crystal display device according to claim 6, wherein the substrate is flexible.

16. The liquid crystal display device according to claim 8, wherein the insulating layer is further in direct contact with the oxide semiconductor layer in a second region which does not overlap with the gate electrode.