Semiconductor integrated circuit and method of fabricating same

• US 20070018167A1
• Filed: 09/26/2006
• Published: 01/25/2007
• Est. Priority Date: 05/26/1994
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Suzawa, Hideomi, Takemura, Yasuhiko
• Granted Patent: US 7,528,406 B2
• Time in Patent Office: Days
• US Class Current: 257/66
• CPC Class Codes: H01L 27/12 the substrate being other than a semiconductor body, e.g. an insulating body
• CPC Class Codes: H01L 27/1244 for preventing breakage, peeling or short circuiting
• 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 29/78636 with supplementary region or layer for improving the flatness of the device
• CPC Class Codes: Y10S 257/90 MOSFET type gate sidewall insulating spacer

Abstract

A semiconductor integrated circuit comprising thin-film transistors in each of which the second wiring is prevented from breaking at steps. A silicon nitride film is formed on gate electrodes and on gate wiring extending from the gate electrodes. Substantially triangular regions are formed out of an insulator over side surfaces of the gate electrodes and of the gate wiring. The presence of these substantially triangular side walls make milder the steps at which the second wiring goes over the gate wiring. This suppresses breakage of the second wiring.

Claims

1. A semiconductor device comprising:

a gate electrode of a transistor and a wiring which is an extension of the gate electrode formed over an insulating surface;

a side wall formed adjacent to a side surface of the gate electrode;

a first insulating film interposed between the side wall and the side surface of the gate electrode, and extending below the side wall; and

a second insulating film formed over and being in contact with the gate electrode of the transistor, the side wall, the first insulating film and the wiring.

2. A semiconductor device according to claim 1, wherein each of the gate electrode and the wiring comprises aluminum.

3. A semiconductor device according to claim 1, wherein the first insulating film comprises a silicon nitride film.

4. A semiconductor device according to claim 1, wherein the second insulating film comprises a silicon oxide film.

5. A semiconductor device according to claim 1, wherein the side wall comprises a silicon oxide film.

6. A semiconductor device according to claim 1, wherein the transistor is a thin film transistor.

7. A semiconductor device according to claim 1, wherein the gate electrode of the transistor is not overlapped with a lightly doped region of the transistor.

8. A semiconductor device according to claim 1, wherein an etching rate of the first insulating film is different from that of the side wall.

9. A semiconductor device according to claim 1, wherein a thickness of the gate electrode of the transistor and a thickness of the wiring are 4000 to 6000 Å

.

10. A semiconductor device according to claim 1, wherein the wiring is a gate wiring.

11. A semiconductor device comprising:

a gate electrode of a transistor and a first wiring which is an extension of the gate electrode formed over an insulating surface;

a side wall formed adjacent to a side surface of the gate electrode;

a first insulating film interposed between the side wall and the side surface of the gate electrode, and extending below the side wall;

a second insulating film formed over and being in contact with the gate electrode of the transistor, the side wall, the first insulating film and the first wiring; and

a second wiring formed over the second insulating film and crossing over the first wiring.

12. A semiconductor device according to claim 11, wherein each of the gate electrode, the first wiring and the second wiring comprises aluminum.

13. A semiconductor device according to claim 11, wherein the first insulating film comprises a silicon nitride film.

14. A semiconductor device according to claim 11, wherein the second insulating film comprises a silicon oxide film.

15. A semiconductor device according to claim 11, wherein the side wall comprises a silicon oxide film.

16. A semiconductor device according to claim 11, wherein the transistor is a thin film transistor.

17. A semiconductor device according to claim 11, wherein the gate electrode of the transistor is not overlapped with a lightly doped region of the transistor.

18. A semiconductor device according to claim 11, wherein an etching rate of the first insulating film is different from that of the side wall.

19. A semiconductor device according to claim 11, wherein a thickness of the gate electrode of the transistor and a thickness of the first wiring are 4000 to 6000 Å

.

20. A semiconductor device according to claim 11, wherein the first wiring is a gate wiring.