Semiconductor device and method for manufacturing semiconductor device

• US 9,780,219 B2
• Filed: 11/15/2016
• Issued: 10/03/2017
• Est. Priority Date: 07/20/2012
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Koezuka, Junichi, Sasaki, Toshinari, Tochibayashi, Katsuaki, Yamazaki, Shunpei
• Primary Examiner(s): MILLER, JAMI VALENTINE
• Application Number:
  US15/351,775
• Publication Number:
  US 20170062623A1
• Time in Patent Office: 322 Days
• Field of Search: 257 43, 438104
• CPC Class Codes: G02F 1/13306 Circuit arrangements or driving methods for the control of single liquid crystal cells G02F1/132, G02F1/133382 take precedence
• CPC Class Codes: G02F 1/133345 Insulating layers G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/1339 Gaskets; Spacers; Sealing of cells
• CPC Class Codes: G02F 1/134309 characterised by their geometrical arrangement
• CPC Class Codes: G02F 1/13439 characterised by their electrical, optical, physical properties; materials therefor; method of making
• 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 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G02F 2201/121 common or background
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• 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 27/1248 with a particular composition or shape of the interlayer dielectric specially adapted to the circuit arrangement
• CPC Class Codes: H01L 27/14612 involving a transistor
• CPC Class Codes: H01L 27/14616 characterised by the channel of the transistor, e.g. channel having a doping gradient
• CPC Class Codes: H01L 27/15 including semiconductor components having potential barriers, specially adapted for light emission
• CPC Class Codes: H01L 29/66742 Thin film unipolar transistors
• CPC Class Codes: H01L 29/78606 with supplementary region or layer in the thin film or in the insulated bulk substrate supporting it for controlling or increasing the safety of the device H01L29/78642, H01L29/78645 take precedence
• 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: H10K 59/1213 the pixel elements being TFTs
• CPC Class Codes: H10K 59/124 Insulating layers formed between TFT elements and OLED elements

Abstract

A change in electrical characteristics of a semiconductor device including an interlayer insulating film over a transistor including an oxide semiconductor as a semiconductor film is suppressed. The structure includes a first insulating film which includes a void portion in a step region formed by a source electrode and a drain electrode over the semiconductor film and contains silicon oxide as a component, and a second insulating film containing silicon nitride, which is provided in contact with the first insulating film to cover the void portion in the first insulating film. The structure can prevent the void portion generated in the first insulating film from expanding outward.

Claims

1. A display device comprising:

a substrate;

a pixel portion;

a transistor in the pixel portion and on the substrate, the transistor comprising;

a gate electrode on the substrate;

a gate insulating film comprising a first oxide insulating film over the gate electrode;

an oxide semiconductor film on the gate insulating film and in contact with the first oxide insulating film;

a source electrode and a drain electrode on the oxide semiconductor film;

a second oxide insulating film on and in contact with the source electrode, the drain electrode, and the oxide semiconductor film; and

a nitride insulating film over the second oxide insulating film;

an interlayer insulating film formed from an organic material over the nitride insulating film; and

an electrode over the interlayer insulating film and electrically connected to the drain electrode through an opening formed in the interlayer insulating film,

wherein side end surfaces of the source electrode and the drain electrode form steps,

wherein portions of the second oxide insulating film covering the steps comprise void portions, and

wherein the nitride insulating film covers the void portions of the second oxide insulating film.

4. The display device according to claim 1,

wherein the second oxide insulating film has a thickness larger than the nitride insulating film.

7. The display device according to claim 1,

wherein the second oxide insulating film comprises a stack of layers.

10. The display device according to claim 1,

wherein the second oxide insulating film has a density higher than or equal to 2.26 g/cm³ and lower than or equal to 2.50 g/cm³.

13. The display device according to claim 1,

wherein the void portions are due to the steps of the side end surfaces of the source electrode and the drain electrode.

16. The display device according to claim 1, further comprising a flexible printed circuit electrically connected to the pixel portion.

2. A display device comprising:

a substrate;

a pixel portion;

a transistor in the pixel portion and on the substrate, the transistor comprising;

a gate electrode on the substrate;

a gate insulating film comprising a first oxide insulating film over the gate electrode, the first oxide insulating film being a first silicon oxide film;

an oxide semiconductor film on the gate insulating film and in contact with the first oxide insulating film;

a source electrode and a drain electrode on the oxide semiconductor film;

a second oxide insulating film on and in contact with the source electrode, the drain electrode, and the oxide semiconductor film, the second oxide insulating film being a second silicon oxide film; and

a silicon nitride film over the second oxide insulating film;

an interlayer insulating film formed from an organic material over the silicon nitride film; and

an electrode over the interlayer insulating film and electrically connected to the drain electrode through an opening formed in the interlayer insulating film,

wherein side end surfaces of the source electrode and the drain electrode form steps,

wherein portions of the second oxide insulating film covering the steps comprise void portions, and

wherein the silicon nitride film covers the void portions of the second oxide insulating film.

5. The display device according to claim 2,

wherein the second oxide insulating film has a thickness larger than the silicon nitride film.

8. The display device according to claim 2,

wherein the second oxide insulating film comprises a stack of layers.

11. The display device according to claim 2,

wherein the second oxide insulating film has a density higher than or equal to 2.26 g/cm³ and lower than or equal to 2.50 g/cm³.

14. The display device according to claim 2,

wherein the void portions are due to the steps of the side end surfaces of the source electrode and the drain electrode.

17. The display device according to claim 2, further comprising a flexible printed circuit electrically connected to the pixel portion.

3. A display device comprising:

a substrate;

a pixel portion;

a transistor in the pixel portion and on the substrate, the transistor comprising;

a gate electrode on the substrate;

a gate insulating film comprising a first oxide insulating film over the gate electrode, the first oxide insulating film being a first silicon oxide film;

an oxide semiconductor film on the gate insulating film and in contact with the first oxide insulating film;

a source electrode and a drain electrode on the oxide semiconductor film;

a second oxide insulating film on and in contact with the source electrode, the drain electrode, and the oxide semiconductor film, the second oxide insulating film being a second silicon oxide film; and

a first silicon nitride film over the second oxide insulating film;

an interlayer insulating film formed from an organic material over the first silicon nitride film; and

a liquid crystal element on the interlayer insulating film, the liquid crystal element comprising;

a first electrode electrically connected to the drain electrode through an opening formed in the interlayer insulating film;

a second electrode;

a second silicon nitride film between the first electrode and the second electrode; and

a liquid crystal layer over the first electrode, the second electrode, and the second silicon nitride film,

wherein side end surfaces of the source electrode and the drain electrode form steps,

wherein portions of the second oxide insulating film covering the steps comprise void portions, and

wherein the first silicon nitride film covers the void portions of the second oxide insulating film.

6. The display device according to claim 3,

wherein the second oxide insulating film has a thickness larger than the first silicon nitride film.

9. The display device according to claim 3,

wherein the second oxide insulating film comprises a stack of layers.

12. The display device according to claim 3,

wherein the second oxide insulating film has a density higher than or equal to 2.26 g/cm³ and lower than or equal to 2.50 g/cm³.

15. The display device according to claim 3,

wherein the void portions are due to the steps of the side end surfaces of the source electrode and the drain electrode.

18. The display device according claim 3, further comprising a flexible printed circuit electrically connected to the pixel portion.