Semiconductor device and method for manufacturing the same

• US 8,664,118 B2
• Filed: 07/02/2012
• Issued: 03/04/2014
• Est. Priority Date: 07/08/2011
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Ishizuka, Akihiro, Hanaoka, Kazuya, Sasagawa, Shinya, Nagamatsu, Sho
• Primary Examiner(s): Picardat, Kevin M
• Application Number:
  US13/539,907
• Publication Number:
  US 20130011961A1
• Time in Patent Office: 610 Days
• Field of Search: 438/149, 438/479, 438/690, 438/691, 438/778, 438/787, 438/692
• US Class Current: 438/692
• CPC Class Codes: H01L 21/02422 Non-crystalline insulating materials, e.g. glass, polymers
• CPC Class Codes: H01L 21/02488 Insulating materials
• CPC Class Codes: H01L 21/02554 Oxides
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/02658 Pretreatments cleaning in general H01L21/02041
• CPC Class Codes: H01L 21/02661 In-situ cleaning
• CPC Class Codes: H01L 21/3105 After-treatment
• 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 29/78636 with supplementary region or layer for improving the flatness of the device
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate

Abstract

An object is to provide a semiconductor device having excellent characteristics, in which a channel layer includes an oxide semiconductor with high crystallinity. In addition, a semiconductor device including a base film with improved planarity is provided. CMP treatment is performed on the base film of the transistor and plasma treatment is performed thereon after the CMP treatment, whereby the base film can have a center line average roughness Ra₇₅ of less than 0.1 nm. The oxide semiconductor layer with high crystallinity is formed over the base film having planarity, which is obtained by the combination of the plasma treatment and the CMP treatment, thereby improving the characteristics of the semiconductor device.

Claims

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

forming a base film over a substrate;

performing chemical mechanical polishing treatment on the base film;

performing plasma treatment on the base film after the chemical mechanical polishing treatment; and

forming an oxide semiconductor layer over a planar surface which is obtained by the plasma treatment and the chemical mechanical polishing treatment.

2. The method for manufacturing a semiconductor device according to claim 1, wherein the plasma treatment is plasma treatment using a rare gas.

3. The method for manufacturing a semiconductor device according to claim 1, wherein the substrate is a semiconductor substrate.

4. The method for manufacturing a semiconductor device according to claim 1, wherein the substrate is a glass substrate.

5. The method for manufacturing a semiconductor device according to claim 1, wherein the plasma treatment is performed with an inductively coupled plasma etching apparatus.

6. The method for manufacturing a semiconductor device according to claim 1, wherein the oxide semiconductor layer comprises In—

Ga—

Zn—

O-based oxide semiconductor.

7. The method for manufacturing a semiconductor device according to claim 1, wherein the oxide semiconductor layer includes a crystal having a c-axis alignment.

8. The method for manufacturing a semiconductor device according to claim 1, wherein the center line average roughness Ra₇₅ of the surface of the base film is less than or equal to 0.1 nm.

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

forming a base film over a substrate;

performing first plasma treatment on the base film;

performing chemical mechanical polishing treatment on the base film after the first plasma treatment;

performing second plasma treatment on the base film after the chemical mechanical polishing treatment; and

forming an oxide semiconductor layer over a planar surface which is obtained by the first plasma treatment, the chemical mechanical polishing treatment, and the second plasma treatment.

10. The method for manufacturing a semiconductor device according to claim 9, wherein the first plasma treatment and the second plasma treatment are each plasma treatment using a rare gas.

11. The method for manufacturing a semiconductor device according to claim 9, wherein the base film is any of a silicon oxide film, a gallium oxide film, a hafnium oxide film, and an aluminum oxide film.

12. The method for manufacturing a semiconductor device according to claim 9, wherein the substrate is a semiconductor substrate.

13. The method for manufacturing a semiconductor device according to claim 9, wherein the substrate is a glass substrate.

14. The method for manufacturing a semiconductor device according to claim 9, wherein the plasma treatment is performed with an inductively coupled plasma etching apparatus.

15. The method for manufacturing a semiconductor device according to claim 9, wherein the oxide semiconductor layer comprises In—

Ga—

Zn—

O-based oxide semiconductor.

16. The method for manufacturing a semiconductor device according to claim 9, wherein the oxide semiconductor layer includes a crystal having a c-axis alignment.

17. The method for manufacturing a semiconductor device according to claim 9, wherein the center line average roughness Ra₇₅ of the surface of the base film is less than or equal to 0.1 nm.