METHOD FOR MANUFACTURING LIGHT-EMITTING DISPLAY DEVICE

• US 20120061673A1
• Filed: 09/07/2011
• Published: 03/15/2012
• Est. Priority Date: 09/10/2010
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei, Koyama, Jun, Hatano, Kaoru
• Granted Patent: US 9,142,568 B2
• Time in Patent Office: Days
• US Class Current: 257/59
• 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 27/1255 integrated with passive devices, e.g. auxiliary capacitors
• CPC Class Codes: H01L 27/127 with a particular formation, treatment or patterning of the active layer specially adapted to the circuit arrangement
• CPC Class Codes: H01L 29/41733 for thin film transistors with insulated gate

Abstract

It is an object of one embodiment of the present invention to manufacture a light-emitting display device by simplifying a manufacturing process of a transistor, without an increase in the number of steps as well as the number of photomasks as compared to those in the conventional case. A step for processing a semiconductor layer into an island shape is omitted by using a high-resistance oxide semiconductor which is intrinsic or substantially intrinsic for the semiconductor layer, used to form transistors. Formation of an opening in the semiconductor layer or an insulating layer formed over the semiconductor layer and etching of an unnecessary portion of the semiconductor layer are performed at the same time; thus, the number of photolithography steps is reduced.

Claims

1. An electronic device comprising:

an insulating substrate;

a semiconductor layer formed over the insulating substrate;

a first thin film transistor formed over the insulating substrate and comprising a first channel formation region in a first region of the semiconductor layer; and

;

a second thin film transistor formed over the insulating substrate and comprising a second channel formation region in a second region of the semiconductor layer,

wherein the semiconductor layer is continuously formed in the first region, in the second region, and along a path linking the first region and the second region.

4. An electronic device according to claim 1,

wherein the semiconductor layer comprises an opening forming a separation region over a gate wiring.

7. An electronic device according to claim 1,

wherein the semiconductor layer comprises an oxide semiconductor layer.

10. An electronic device according to claim 1,

further comprising a capacitor making use of a third region of the semiconductor layer,

wherein the semiconductor layer is continuously formed in the third region, and along a path linking the first region, the second region, and the third region.

13. An electronic device according to claim 1,

wherein the electronic device is one of a television set, a monitor of a computer, a camera, a digital photo frame, a mobile phone set, a portable game machine, a portable information terminal, an audio reproducing device, and a large-sized game machine.

2. A display device comprising:

an insulating substrate;

a semiconductor layer formed over the insulating substrate;

a first thin film transistor formed over the insulating substrate and comprising a first channel formation region in a first region of the semiconductor layer, a first gate layer, and a first source or drain layer;

a second thin film transistor formed over the insulating substrate and comprising a second channel formation region in a second region of the semiconductor layer, a second gate layer electrically connected to the first source or drain layer, a second source layer, and a second drain layer;

an insulating film formed over the semiconductor layer, the first thin film transistor, and the second thin film transistor; and

a pixel electrode formed over the insulating film and electrically connected to one of the second source layer and the second drain layer,

wherein the semiconductor layer is continuously formed in the first region, in the second region, and along a path linking the first region and the second region.

5. A display device according to claim 2,

wherein the semiconductor layer comprises an opening forming a separation region over a gate wiring made of a portion of the first gate layer.

8. A display device according to claim 2,

wherein the semiconductor layer comprises an oxide semiconductor layer.

11. A display device according to claim 2,

further comprising a capacitor in which a portion of the second gate layer, a third region of the semiconductor layer, and a portion of the other of the second source layer and the second drain layer overlap with each other,

wherein the semiconductor layer is continuously formed in the third region, and along a path linking the first region, the second region, and the third region.

14. A display device according to claim 2,

wherein the display device is one of a television set, a monitor of a computer, a camera, a digital photo frame, a mobile phone set, a portable game machine, a portable information terminal, an audio reproducing device, and a large-sized game machine.

3. A display device comprising:

an insulating substrate;

a semiconductor layer formed over the insulating substrate;

a first thin film transistor formed over the insulating substrate and comprising a first channel formation region in a first region of the semiconductor layer, a first gate layer, and a first source or drain layer;

a second thin film transistor formed over the insulating substrate and comprising a second channel formation region in a second region of the semiconductor layer, a second gate layer electrically connected to the first source or drain layer, a second source layer, and a second drain layer;

an insulating film formed over the semiconductor layer, the first thin film transistor, and the second thin film transistor;

a first pixel electrode formed over the insulating film and electrically connected to one of the second source layer and the second drain layer;

an EL layer formed over the first pixel electrode;

a second pixel electrode formed over the EL layer; and

a connection portion where the first gate layer is not covered by the insulating film,

wherein the semiconductor layer is continuously formed in the first region, in the second region, and along a path linking the first region and the second region.

6. A display device according to claim 3,

wherein the semiconductor layer comprises an opening forming a separation region over a gate wiring made of a portion of the first gate layer.

9. A display device according to claim 3,

wherein the semiconductor layer comprises an oxide semiconductor layer.

12. A display device according to claim 3,

further comprising a capacitor in which a portion of the second gate layer, a third region of the semiconductor layer, and a portion of the other of the second source layer and the second drain layer overlap with each other,

wherein the semiconductor layer is continuously formed in the third region, and along a path linking the first region, the second region, and the third region.

15. A display device according to claim 3,

wherein the display device is one of a television set, a monitor of a computer, a camera, a digital photo frame, a mobile phone set, a portable game machine, a portable information terminal, an audio reproducing device, and a large-sized game machine.

16. A method for manufacturing a light-emitting display device comprising the steps of:

forming a first conductive film over a substrate having an insulating surface;

performing a first photolithography step on the first conductive film to form a first gate layer and a second gate layer;

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

forming a semiconductor film over the first insulating film;

forming a second conductive film over the semiconductor film;

performing a second lithography step on the second conductive film to form a first source layer and a first drain layer of a first transistor comprising the first gate layer, and a second source layer and a second drain layer of a second transistor comprising the second gate layer;

forming a second insulating film over the first transistor, the second transistor, and the semiconductor film;

performing a third lithography step, after formation of the second insulating film, to form;

a first opening exposing part of one of the first source layer and the first drain layer and a second opening exposing part of one of the second source layer and the second drain layer by selectively etching the second insulating film; and

a third opening exposing part of the second gate layer and a fourth opening exposing part of the substrate by selectively etching the second insulating film, the semiconductor film, and the first insulating film,

forming a third conductive film over the second insulating film so as to cover the first opening, the second opening, the third opening, and the fourth opening; and

performing a fourth lithography step on the third conductive film to form;

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

a connection layer electrically connecting the one of the first source layer and the first drain layer to the second gate layer through the first opening and the third opening,

wherein the first transistor and the second transistor comprise respectively a first region and a second region of the semiconductor layer; and

wherein the semiconductor layer is continuously formed in the first region, in the second region, and along a path linking the first region and the second region.

18. A method for manufacturing a light-emitting display device according to claim 16,

wherein the semiconductor layer is an oxide semiconductor layer, and

further comprising a step of heating the semiconductor layer.

20. A method for manufacturing a light-emitting display device according to claim 16,

further comprising formation of a fourth opening by the same steps as formation of the first opening and the second opening, the fourth opening exposing part of a wiring portion of the second gate layer to form a separation region in the semiconductor layer.

22. A method for manufacturing a light-emitting display device according to claim 16,

wherein a capacitor is formed, capacitor in which a portion of the second gate layer, a third region of the semiconductor layer, and a portion of the other of the second source layer and the second drain layer overlapped with each other,

wherein the semiconductor layer is continuously formed in the third region, and along a path linking the first region, the second region, and the third region.

24. A method for manufacturing a light-emitting display device according to claim 16, further comprising the step of:

forming a photosensitive planarization layer over the second insulating film before performing the third lithography step,

wherein the photosensitive planarization layer is used as a mask for selectively etching the second insulating layer, the semiconductor layer, and the first insulating layer when forming the first opening, the second opening, the third opening, and the fourth opening.

25. A method for manufacturing a light-emitting display device according to claim 16, further comprising the step of:

forming a photosensitive planarization layer over the second insulating film before performing the fourth lithography step,

wherein the photosensitive planarization layer is used as a mask for selectively etching the second insulating layer when forming the third opening.

26. A method for manufacturing a light-emitting display device according to claim 16,

wherein the light-emitting display is applied to one of a television set, a monitor of a computer, a camera, a digital photo frame, a mobile phone set, a portable game machine, a portable information terminal, an audio reproducing device, and a large-sized game machine.

17. A method for manufacturing a light-emitting display device comprising the steps of:

forming a first conductive film over a substrate having an insulating surface;

performing a first photolithography step on the first conductive film to form a first gate layer and a second gate layer;

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

forming a semiconductor film over the first insulating film;

performing a second lithography step, after formation of the semiconductor film, to form a first opening exposing part of the second gate layer and a second opening exposing part of the substrate by selectively etching the semiconductor film and the first insulating film;

forming a second conductive film so as to cover the semiconductor film, the first opening, and the second opening;

performing a third lithography step on the second conductive film to form a first source layer and a first drain layer of a first transistor comprising the first gate layer, and a second source layer and a second drain layer of a second transistor comprising the second gate layer, one of the first source layer, and the second drain layer being electrically connected to the second gate layer through the first opening;

forming a second insulating film over the first transistor, the second transistor, and the semiconductor film;

performing a fourth lithography step, after formation of the second insulating film, to form a third opening exposing part of one of the second source layer and the second drain layer;

forming a third conductive film over the second insulating film so as to cover the third opening; and

performing a fifth lithography step on the third conductive film to form a pixel electrode electrically connected to the one of the second source layer and the second drain layer through the third opening,

wherein the first transistor and the second transistor comprise respectively a first region and a second region of the semiconductor layer; and

wherein the semiconductor layer is continuously formed in the first region, in the second region, and along a path linking the first region and the second region.

19. A method for manufacturing a light-emitting display device according to claim 17,

wherein the semiconductor layer is an oxide semiconductor layer, and

further comprising a step of heating the semiconductor layer.

21. A method for manufacturing a light-emitting display device according to claim 17,

further comprising formation of a fourth opening by the same steps as formation of the first opening and the second opening, the fourth opening exposing part of a wiring portion of the second gate layer to form a separation region in the semiconductor layer.

23. A method for manufacturing a light-emitting display device according to claim 17,

wherein a capacitor is formed, capacitor in which a portion of the second gate layer, a third region of the semiconductor layer, and a portion of the other of the second source layer and the second drain layer overlapped with each other,

wherein the semiconductor layer is continuously formed in the third region, and along a path linking the first region, the second region, and the third region.

27. A method for manufacturing a light-emitting display device according to claim 17,

wherein the light-emitting display is applied to one of a television set, a monitor of a computer, a camera, a digital photo frame, a mobile phone set, a portable game machine, a portable information terminal, an audio reproducing device, and a large-sized game machine.