LIGHT-EMITTING DISPLAY DEVICE AND METHOD FOR MANUFACTURING THE SAME

• US 20120061664A1
• Filed: 09/07/2011
• Published: 03/15/2012
• 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
• Granted Patent: US 8,647,919 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• 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: H10K 2102/311 Flexible OLED
• CPC Class Codes: H10K 59/1201 Manufacture or treatment
• CPC Class Codes: H10K 59/1213 the pixel elements being TFTs
• CPC Class Codes: H10K 59/123 Connection of the pixel electrodes to the thin film transistors [TFT]
• CPC Class Codes: H10K 59/124 Insulating layers formed between TFT elements and OLED elements
• CPC Class Codes: H10K 71/80 using temporary substrates

Abstract

Provided is a method to manufacture a light-emitting 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 light-emitting display device comprising a pixel over a flexible substrate, the pixel comprising:

a first thin film transistor comprising;

a first oxide semiconductor layer; and

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

a second thin film transistor comprising;

a gate electrode; and

a second source electrode and a second drain electrode with a second oxide semiconductor layer between the gate electrode and the second source electrode and between the gate electrode and the second drain electrode, wherein the second source electrode and the second drain electrode are electrically connected to the second oxide semiconductor layer; and

a light-emitting element comprising;

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

an organic compound layer over the first pixel electrode; and

a second pixel electrode over the organic compound layer,

wherein the gate electrode is electrically connected to one of the first source electrode and the first drain electrode, and

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

2. The light-emitting display device according to claim 1,

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

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

3. The light-emitting display device according to claim 1,

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

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

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

4. The light-emitting display device according to claim 1, further comprising a base layer between the flexible substrate and the first thin film transistor and between the flexible substrate and the second thin film transistor.

5. The light-emitting display device according to claim 1,

wherein the first oxide semiconductor layer and the second oxide semiconductor layer comprise an element selected from gallium and indium.

6. A light-emitting display device comprising a pixel over a flexible substrate, the pixel comprising:

a first thin film transistor comprising;

a first oxide semiconductor layer; and

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

a second thin film transistor comprising;

a gate electrode; and

a second source electrode and a second drain electrode with a second oxide semiconductor layer between the gate electrode and the second source electrode and between the gate electrode and the second drain electrode, wherein the second source electrode and the second drain electrode are electrically connected to the second oxide semiconductor layer;

a light-emitting element comprising;

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

an organic compound layer over the first pixel electrode; and

a second pixel electrode over the organic compound layer; and

a capacitor comprising;

a capacitor wiring electrically connected to the gate electrode; and

a dielectric layer over the capacitor wiring,

wherein the gate electrode is electrically connected to one of the first source electrode and the first drain electrode, and

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

7. The light-emitting display device according to claim 6,

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

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

8. The light-emitting display device according to claim 6,

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

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

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

9. The light-emitting display device according to claim 6, further comprising a base layer between the flexible substrate and the first thin film transistor and between the flexible substrate and the second thin film transistor.

10. The light-emitting display device according to claim 6,

wherein the first oxide semiconductor layer and the second oxide semiconductor layer comprise an element selected from gallium and indium.

11. A method for manufacturing a light-emitting display device, the method comprising:

forming a separation layer over a substrate;

forming a first gate electrode and a second gate electrode over the separation layer;

forming a gate insulating layer over the first gate electrode and the second gate electrode;

forming an oxide semiconductor layer over the gate insulating layer;

forming a first source electrode, a first drain electrode, a second source electrode, and a second drain electrode over the oxide semiconductor layer so that one of the first source electrode and the first drain electrode is electrically connected to the second gate electrode;

forming an insulating layer over the first source electrode, the first drain electrode, the second source electrode, and the second drain electrode;

forming a first contact hole and a second contact hole simultaneously;

forming a first pixel electrode over the first contact hole and the second contact hole; and

separating the first gate electrode, the second gate electrode, the gate insulating layer, the oxide semiconductor layer, the first source electrode, the first drain electrode, the second source electrode, the second drain electrode, the insulating layer, and the first pixel electrode from the substrate,

wherein the first contact hole is formed in the insulating layer to expose part of one of the second source electrode and the second drain electrode, and

wherein the second contact hole is formed in the insulating layer and the oxide semiconductor layer to expose the gate insulating layer.

12. The method according to claim 11,

wherein the first pixel electrode is in contact with the one of the second source electrode and the second drain electrode in the first contact hole.

13. The method according to claim 11,

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

14. The method according to claim 11,

wherein the first pixel electrode is in contact with a top surface of the gate insulating layer in the second contact hole.

15. The method according to claim 11, further comprising a step of forming a base layer before the formation of the first gate electrode and the second gate electrode.

16. The method according to claim 11,

wherein the oxide semiconductor layer comprises an element selected from gallium and indium.