Liquid crystal display device, EL display device, and manufacturing method thereof

1. A display device comprising:

a first wiring;

a semiconductor layer over the first wiring with a first insulating layer interposed therebetween;

a second insulating layer over and in direct contact with the semiconductor layer;

a second wiring over the second insulating layer, the second wiring electrically connected to the semiconductor layer through an opening formed in the second insulating layer;

a capacitor wiring;

a third insulating layer over the second wiring; and

a pixel electrode electrically connected to the semiconductor layer,

wherein a part of the first wiring is a gate electrode,

wherein a part of the second insulating layer overlaps with a channel region of the semiconductor layer,

wherein the semiconductor layer includes an oxide semiconductor containing indium and zinc,

wherein the second insulating layer contains oxygen, indium and zinc,

wherein the second insulating layer and the semiconductor layer overlap with the first wiring, the second wiring, and the pixel electrode,

wherein a first groove is formed at least in the first insulating layer, the second insulating layer, the third insulating layer, and the semiconductor layer to cross the first wiring,

wherein a second groove is formed at least in the first insulating layer, the second insulating layer, the third insulating layer, and the semiconductor layer between the pixel electrode and the first wiring,

wherein a first part of the first groove overlaps first edges of the first wiring,

wherein a second part of the first groove overlaps second edges of the first wiring,

wherein a third part of the first groove overlaps third edges of the capacitor wiring,

wherein a fourth part of the first groove overlaps fourth edges of the first wiring,

wherein a fifth part of the second groove is between the channel region of the semiconductor layer and the pixel electrode,

wherein the first part, the fourth part and the second part are aligned in a first direction,

wherein the first part, and the third part are aligned in a second direction that is perpendicular to the first direction,

wherein the fourth part, the channel region of the semiconductor layer and the fifth part are aligned in the second direction,

wherein the first groove and the second groove are separated.

2. The display device according to claim 1 , further comprising:

a terminal portion outside a pixel portion that comprises the first wiring, the semiconductor layer, the first insulating layer, the second insulating layer, and the second wiring,

wherein, in the terminal portion, the semiconductor layer, the second insulating layer, and the second wiring are stacked in this order, and

wherein the terminal portion comprises an electrode that is a different layer from the pixel electrode over and electrically connected to the second wiring.

3. The display device according to claim 1 , further comprising:

a third wiring electrically connected to the semiconductor layer through a second opening formed in the second insulating layer; and

a second pixel electrode electrically connected to the semiconductor layer through a third opening formed in the second insulating layer,

wherein the first groove is formed between the first wiring and the third wiring, and

wherein the pixel electrode and the second pixel electrode are adjacent to each other with the third wiring provided therebetween.

4. The display device according to claim 1 ,

wherein the first insulating layer is in direct contact with the semiconductor layer, and

wherein the first insulating layer contains indium, zinc and oxygen.

5. The display device according to claim 4 ,

wherein the oxide semiconductor contains gallium, and

wherein the first insulating layer contains cerium.

6. The display device according to claim 4 ,

wherein the oxide semiconductor contains gallium, and

wherein the first insulating layer contains yttrium.

7. A display device comprising:

a transistor including a gate electrode, a semiconductor layer, a protective layer, a first electrode, and a second electrode;

a first wiring electrically connected to the gate electrode;

a second wiring electrically connected to the first electrode;

a pixel electrode electrically connected to the second electrode;

a capacitor wiring;

a first groove; and

a second groove,

wherein a part of the protective layer overlaps with a channel region of the semiconductor layer,

wherein the semiconductor layer includes an oxide semiconductor containing indium and zinc,

wherein the protective layer contains oxygen, indium and zinc,

wherein the protective layer is provided over and in direct contact with the semiconductor layer, and the semiconductor layer and the protective layer overlap with the first wiring, the second wiring, the pixel electrode, and the capacitor wiring,

wherein the first electrode and the second electrode are electrically connected to the semiconductor layer through first and second openings formed in the protective layer, respectively,

wherein the display device further comprises:

a first insulating layer between the gate electrode and the semiconductor layer; and

a second insulating layer over the protective layer,

wherein the first groove is formed at least in the first insulating layer, the protective layer, the second insulating layer, and the semiconductor layer to cross the first wiring in a line width direction of the first wiring and to cross the capacitor wiring in a line width direction of the capacitor wiring,

wherein, in a direction parallel to a direction in which the second wiring extends, the first groove is longer than the pixel electrode,

wherein the second groove is formed at least in the first insulating layer, the protective layer, the second insulating layer, and the semiconductor layer between the pixel electrode and the first wiring,

wherein a first part of the first groove overlaps a first part of the first wiring,

wherein a second part of the first groove overlaps a second part of the first wiring,

wherein a third part of the first groove overlaps a first part of the capacitor wiring,

wherein a fourth part of the first groove overlaps edges of the first wiring,

wherein a fifth part of the second groove is between the channel region of the semiconductor layer and the pixel electrode,

wherein the first part, the fourth part, and the second part are aligned in a first direction,

wherein the first part and the third part are aligned in a second direction that is perpendicular to the first direction,

wherein the fourth part, the channel region of the semiconductor layer, and the fifth part are aligned in the second direction,

wherein the first groove and the second groove are separated.

8. The display device according to claim 7 , wherein the semiconductor layer is not provided on a bottom surface of the first groove.

9. The display device according to claim 7 , wherein the semiconductor layer is provided on a side surface of the first groove.

10. The display device according to claim 7 , wherein the first groove overlaps with an alignment film.

11. The display device according to claim 7 , wherein the first groove overlaps with the pixel electrode.

12. The display device according to claim 7 , wherein the protective layer includes an oxide insulating material.

13. The display device according to claim 12 , wherein the oxide insulating material is a material in which, in an oxide containing indium, gallium, and zinc, part of the gallium is replaced with at least one element selected from titanium, zirconium, hafnium, and germanium.

14. The display device according to claim 7 , wherein the display device is a liquid crystal display device.

15. The display device according to claim 7 ,

wherein the first insulating layer is in direct contact with the semiconductor layer, and

wherein the first insulating layer contains indium, zinc and oxygen.

16. The display device according to claim 15 ,

wherein the oxide semiconductor contains gallium, and

wherein the first insulating layer contains cerium.

17. The display device according to claim 15 ,

wherein the oxide semiconductor contains gallium, and

wherein the first insulating layer contains yttrium.