Method for manufacturing semiconductor device

• US 8,916,424 B2
• Filed: 01/31/2013
• Issued: 12/23/2014
• Est. Priority Date: 02/07/2012
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Isobe, Atsuo, Hosoya, Kunio
• Primary Examiner(s): STEVENSON, ANDRE C
• Application Number:
  US13/755,862
• Publication Number:
  US 20130203214A1
• Time in Patent Office: 691 Days
• US Class Current: 438/149
• CPC Class Codes: H01L 21/02178 the material containing aluminium, e.g. Al2O3
• CPC Class Codes: H01L 21/02244 of a metallic layer
• CPC Class Codes: H01L 21/0237 Materials
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/383 using diffusion into or out of a solid from or into a gaseous phase
• CPC Class Codes: H01L 21/425 producing ion implantation
• CPC Class Codes: H01L 21/441 Deposition of conductive or insulating materials for electrodes
• CPC Class Codes: H01L 21/47573 Etching the layer
• 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 29/24 including, apart from doping materials or other impurities, only semiconductor materials not provided for in groups H01L29/16, H01L29/18, H01L29/20, H01L29/22 including organic materials H10K99/00
• CPC Class Codes: H01L 29/41733 for thin film transistors with insulated gate
• CPC Class Codes: H01L 29/4908 for thin film semiconductor, e.g. gate of TFT
• CPC Class Codes: H01L 29/495 the conductor material next to the insulator being a simple metal, e.g. W, Mo H01L29/4908, H01L29/4983 take precedence
• CPC Class Codes: H01L 29/517 the insulating material comprising a metallic compound, e.g. metal oxide, metal silicate H01L29/518 takes precedence
• CPC Class Codes: H01L 29/66969 of devices having semiconductor bodies not comprising group 14 or group 13/15 materials comprising selenium or tellurium in uncombined form other than as impurities in semiconductor bodies of other materials, comprising cuprous oxide or cuprous iodide H01L21/02365
• 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: H10B 10/125 the MOSFET being a thin film transistor [TFT]
• CPC Class Codes: H10B 12/05 Making the transistor
• CPC Class Codes: H10B 41/70 the floating gate being an electrode shared by two or more components

Abstract

To improve productivity of a transistor that includes an oxide semiconductor and has good electrical characteristics. In a top-gate transistor including a gate insulating film and a gate electrode over an oxide semiconductor film, a metal film is formed over the oxide semiconductor film, oxygen is added to the metal film to form a metal oxide film, and the metal oxide film is used as a gate insulating film. After an oxide insulating film is formed over the oxide semiconductor film, a metal film may be formed over the oxide insulating film. Oxygen is added to the metal film to form a metal oxide film and added also to the oxide semiconductor film or the oxide insulating film.

Claims

1. A method for manufacturing a semiconductor device comprising the steps of:

forming an oxide semiconductor film over a first oxide insulating film;

etching the oxide semiconductor film to form an island-shaped oxide semiconductor film;

forming an insulating film over the island-shaped oxide semiconductor film;

forming a gate electrode over the insulating film;

forming sidewalls in contact with side surfaces of the gate electrode;

etching part of the insulating film where the gate electrode and the sidewalls do not overlap to form a gate insulating film;

forming a second oxide insulating film over the gate electrode, the sidewalls, and the island-shaped oxide semiconductor film;

forming a metal film over the second oxide insulating film;

adding oxygen to the metal film to form a metal oxide film, and adding oxygen also to the second oxide insulating film;

forming an interlayer insulating film over the metal oxide film; and

forming a pair of contact plugs electrically connected to the island-shaped oxide semiconductor film through openings in the interlayer insulating film, the metal oxide film, and the second oxide insulating film.

2. The method for manufacturing the semiconductor device, according to claim 1,

wherein a material of the metal film is aluminum, gallium, hafnium, or yttrium, and

wherein the metal oxide film is an oxide film or an oxynitride film corresponding to the metal film.

3. The method for manufacturing the semiconductor device, according to claim 1, further comprising the steps of:

forming low-resistance regions in the island-shaped oxide semiconductor film by adding a dopant to the island-shaped oxide semiconductor film with use of the gate electrode as a mask after the gate electrode is formed; and

forming the sidewalls over the island-shaped oxide semiconductor film including the low-resistance regions.

4. The method for manufacturing the semiconductor device, according to claim 1, wherein the island-shaped oxide semiconductor film comprises one or more elements selected from In, Ga, Sn, and Zn.

5. The method for manufacturing the semiconductor device, according to claim 1, further comprising the steps of:

forming a transistor over a semiconductor substrate;

forming a planarization insulating film over the transistor;

forming a wiring electrically connected to the transistor through a second opening in the planarization insulating film;

forming the first oxide insulating film over the planarization insulating film and the wiring; and

electrically connecting one of the pair of contact plugs to the wiring.

6. The method for manufacturing the semiconductor device, according to claim 1, wherein the semiconductor device is a central processing unit, a microprocessor, a random access memory, a converter, a power transistor, a thyristor, an image sensor, an electro-optical device, or a light-emitting display device.

7. A method for manufacturing a semiconductor device comprising the steps of:

forming an oxide semiconductor film over a first oxide insulating film;

etching the oxide semiconductor film to form an island-shaped oxide semiconductor film;

forming a first metal film over the island-shaped oxide semiconductor film;

adding oxygen to the first metal film to form a first metal oxide film, and

adding oxygen also to the island-shaped oxide semiconductor film;

forming a gate electrode over the first metal oxide film;

forming sidewalls in contact with side surfaces of the gate electrode;

etching part of the first metal oxide film where the gate electrode and the sidewalls do not overlap;

forming a second oxide insulating film over the gate electrode, the sidewalls, and the island-shaped oxide semiconductor film;

forming a second metal film over the second oxide insulating film;

adding oxygen to the second metal film to form a second metal oxide film, and adding oxygen also to the second oxide insulating film;

forming an interlayer insulating film over the second metal oxide film; and

forming a pair of contact plugs electrically connected to the island-shaped oxide semiconductor film through openings in the interlayer insulating film, the second metal oxide film, and the second oxide insulating film.

8. The method for manufacturing the semiconductor device, according to claim 7,

wherein a material of the first metal film is aluminum, gallium, hafnium, or yttrium, and

wherein the first metal oxide film is an oxide film or an oxynitride film corresponding to the first metal film.

9. The method for manufacturing a semiconductor device, according to claim 7,

wherein a material of the second metal film is aluminum, gallium, hafnium, or yttrium, and

wherein the second metal oxide film is an oxide film or an oxynitride film corresponding to the second metal film.

10. The method for manufacturing the semiconductor device, according to claim 7, further comprising the steps of:

forming low-resistance regions in the island-shaped oxide semiconductor film by adding a dopant to the island-shaped oxide semiconductor film with use of the gate electrode as a mask after the gate electrode is formed; and

forming the sidewalls over the island-shaped oxide semiconductor film including the low-resistance regions.

11. The method for manufacturing the semiconductor device, according to claim 7, wherein the island-shaped oxide semiconductor film comprises one or more elements selected from In, Ga, Sn, and Zn.

12. The method for manufacturing the semiconductor device, according to claim 7, further comprising the steps of:

forming a transistor over a semiconductor substrate;

forming a planarization insulating film over the transistor;

forming a wiring electrically connected to the transistor through a second opening in the planarization insulating film;

forming the first oxide insulating film over the planarization insulating film and the wiring; and

electrically connecting one of the pair of contact plugs to the wiring.

13. The method for manufacturing the semiconductor device, according to claim 7, wherein the semiconductor device is a central processing unit, a microprocessor, a random access memory, a converter, a power transistor, a thyristor, an image sensor, an electro-optical device, or a light-emitting display device.

14. The method for manufacturing the semiconductor device, according to claim 7, further comprising the steps of:

forming a third oxide insulating film over the island-shaped oxide semiconductor film before forming the first metal film.