THIN-FILM TRANSISTOR ELEMENT AND METHOD FOR PRODUCING SAME, ORGANIC EL DISPLAY ELEMENT AND METHOD FOR PRODUCING SAME, AND ORGANIC EL DISPLAY DEVICE

• US 20140042417A1
• Filed: 10/22/2013
• Published: 02/13/2014
• Est. Priority Date: 06/21/2011
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: OKUMOTO, Yuko, MIYAMOTO, Akihito, UKEDA, Takaaki
• Granted Patent: US 9,024,449 B2
• Time in Patent Office: Days
• US Class Current: 257/40
• CPC Class Codes: H01L 27/1292 using liquid deposition, e.g. printing
• CPC Class Codes: H10K 10/462 Insulated gate field-effect transistors [IGFETs]
• CPC Class Codes: H10K 10/484 characterised by the channel regions
• CPC Class Codes: H10K 50/80 Constructional details
• CPC Class Codes: H10K 59/123 Connection of the pixel electrodes to the thin film transistors [TFT]
• CPC Class Codes: H10K 59/125 including organic TFTs [OTFT]
• CPC Class Codes: H10K 71/00 Manufacture or treatment specially adapted for the organic devices covered by this subclass

Abstract

A thin film transistor element includes: a gate electrode; a source electrode and a drain electrode; an insulating layer; partition walls; and an organic semiconductor layer. The partition walls define a first aperture. Within the first aperture, at least a part of the source electrode and at least a part of the drain electrode are in contact with the semiconductor layer. The partition walls have side face portions facing the first aperture, and some of the side face portions have gentler slopes than the rest of the side face portions.

Claims

1. A thin film transistor element comprising:

a gate electrode;

an insulating layer disposed on the gate electrode;

a source electrode and a drain electrode disposed on the insulating layer with a gap therebetween;

partition walls surrounding at least a part of the source electrode and at least a part of the drain electrode, the partition walls having liquid-repellant surfaces and defining a first aperture; and

an organic semiconductor layer disposed on the source electrode and the drain electrode within the first aperture so as to cover the source electrode and the drain electrode and fill the gap between the source electrode and the drain electrode, the organic semiconductor layer being in contact with the source electrode and the drain electrode, wherein

the partition walls have side face portions facing the first aperture, and some of the side face portions have gentler slopes than the rest of the side face portions.

2. The thin film transistor element of claim 1, wherein

the first aperture with the organic semiconductor layer formed inside the first aperture functions as a channel portion,

the partition walls define a second aperture with a gap between the first aperture and the second aperture, the second aperture not functioning as a channel portion, and

among the side face portions facing the first aperture, said some of the side face portions having the gentler slopes do not include a side face portion that is adjacent to the second aperture.

3. The thin film transistor element of claim 2, wherein

among the side face portions facing the first aperture, said some of the side face portions having the gentler slopes are located opposite the side face portion that is adjacent to the second aperture with respect to the first aperture.

4. The thin film transistor element of claim 2, wherein

at least a part of the source electrode, at least a part of the drain electrode, or a connection wire electrically connected with the source electrode or the drain electrode is formed at a bottom of the second aperture.

5. The thin film transistor element of claim 2, wherein

among the side face portions facing the first aperture, the side face portion that is adjacent to the second aperture has the steepest slope.

6. The thin film transistor element of claim 1, wherein

an inclination of each of the side face portions is defined as an angle thereof with respect to an upper surface of an underlayer on which the partition walls are formed.

7. The thin film transistor element of claim 1, wherein

inclination angles of the gentler slopes of said some of the side face portions are smaller than inclination angles of the rest of the side face portions by 5 degrees or more.

8. An organic EL display element comprising:

the thin film transistor element of claim 1;

a planarizing film formed above the thin film transistor element and having a contact hole formed therein;

a lower electrode formed on the planarizing film so as to cover the planarizing film and a side surface of the planarizing film defining the contact hole, and electrically connected with one of the source electrode and the drain electrode;

an upper electrode formed above the lower electrode; and

an organic light-emitting layer interposed between the lower electrode and the upper electrode.

9. An organic EL display element comprising:

2. n film transistor element of claim 2;

a planarizing film formed above the thin film transistor element and having a contact hole formed therein;

a lower electrode formed on the planarizing film so as to cover the planarizing film and a side surface of the planarizing film defining the contact hole, and electrically connected with one of the source electrode and the drain electrode;

an upper electrode formed above the lower electrode; and

an organic light-emitting layer interposed between the lower electrode and the upper electrode, wherein

a bottom of the contact hole is in communication with the second aperture.

10. An organic EL display device comprising the organic EL display element of claim 8.

11. An organic EL display device comprising the organic EL display element of claim 9.

12. A method of manufacturing a thin film transistor element comprising:

a first step of forming a gate electrode on a substrate;

a second step of forming an insulating layer above the gate electrode;

a third step of forming a source electrode and a drain electrode on the insulating layer so as to be adjacent to each other with a gap therebetween;

a fourth step of depositing a layer of photosensitive resist material such that, above the insulating layer, the layer of photosensitive resist material covers the source electrode and the drain electrode as well as areas therearound;

a fifth step of forming partition walls on the insulating layer by performing mask exposure and patterning of the layer of photosensitive resist material, the partition walls having liquid-repellant surfaces and defining a first aperture, the first aperture surrounding at least a part of the source electrode and at least a part of the drain electrode; and

a sixth step of forming an organic semiconductor layer so as to be in contact with the source electrode and the drain electrode by applying organic semiconductor material within the first aperture and drying the organic semiconductor material so applied, wherein

in the fifth step, the partition walls are formed such that the partition walls have side face portions facing the first aperture, and such that some of the side face portions have gentler slopes than the rest of the side face portions.

13. The method of claim 12, wherein

in the fifth step,

the first aperture is formed to function as a channel portion with the organic semiconductor layer to be formed inside the first aperture,

the partition walls are formed to define a second aperture with a gap between the first aperture and the second aperture, the second aperture not functioning as a channel portion, and

the partition walls are formed such that among the side face portions facing the first aperture, said some of the side face portions having the gentler slopes do not include a side face portion that is adjacent to the second aperture.

14. The method of claim 12, wherein

in the fifth step,

said rest of the side face portions are formed by a greater degree of exposure to light relative to said some of the side face portions having the gentler slopes.

15. The method of claim 12, wherein

in the fifth step,

after sections of the layer of photosensitive resist material corresponding in position to the side face portions facing the first aperture are exposed to light,

sections of the layer of photosensitive resist material corresponding in position to said rest of the side face portions are further exposed to light.

16. The method of claim 12, wherein

in the fifth step,

the layer of photosensitive resist material is exposed to light through a mask, and sections of the mask corresponding in position to said rest of the side face portions have a higher optical transmission rate than sections of the mask corresponding in position to said some of the side face portions having the gentler slopes.

17. A method of manufacturing an organic EL display element comprising:

forming a thin film transistor element;

forming a planarizing film with a contact hole therein on the thin film transistor element;

forming a lower electrode on the planarizing film so as to cover the planarizing film and a side surface of the planarizing film defining the contact hole, the lower electrode being electrically connected with the thin film transistor element;

forming an organic light-emitting layer above the lower electrode; and

forming an upper electrode above the organic light-emitting layer,

the forming of the thin film transistor element comprising;

a first step of forming a gate electrode on a substrate;

a second step of forming an insulating layer above the gate electrode;

a third step of forming a source electrode and a drain electrode on the insulating layer so as to be adjacent to each other with a gap therebetween;

a fourth step of depositing a layer of photosensitive resist material such that, above the insulating layer, the layer of photosensitive resist material covers the source electrode and the drain electrode as well as areas therearound;

a fifth step of forming partition walls on the insulating layer by performing mask exposure and patterning of the layer of photosensitive resist material, the partition walls having liquid-repellant surfaces and defining a first aperture, the first aperture surrounding at least a part of the source electrode and at least a part of the drain electrode; and

a sixth step of forming an organic semiconductor layer so as to be in contact with the source electrode and the drain electrode by applying organic semiconductor material within the first aperture and drying the organic semiconductor material so applied, wherein

in the fifth step, the partition walls are formed such that the partition walls have side face portions facing the first aperture, and such that some of the side face portions have gentler slopes than the rest of the side face portions.

18. The method of claim 17, wherein

in the fifth step of the forming of the thin film transistor element,

the first aperture is formed to function as a channel portion with the organic semiconductor layer to be formed inside the first aperture,

the partition walls are formed to define a second aperture with a gap between the first aperture and the second aperture, the second aperture not functioning as a channel portion, and

the partition walls are formed such that among the side face portions facing the first aperture, said some of the side face portions having the gentler slopes do not include a side face portion that is adjacent to the second aperture.