Semiconductor device and method for manufacturing semiconductor device

• US 9,985,056 B2
• Filed: 10/10/2016
• Issued: 05/29/2018
• Est. Priority Date: 10/12/2015
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei, Sato, Takahiro, Jintyou, Masami
• Primary Examiner(s): Nguyen, Cuong B
• Application Number:
  US15/289,621
• Publication Number:
  US 20170104018A1
• Time in Patent Office: 596 Days
• CPC Class Codes: H01L 27/1218 with a particular composition or structure of the substrate
• CPC Class Codes: H01L 27/1222 with a particular composition, shape or crystalline structure of the active 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 27/127 with a particular formation, treatment or patterning of the active layer specially adapted to the circuit arrangement
• CPC Class Codes: H01L 27/1288 employing particular masking sequences or specially adapted masks, e.g. half-tone mask
• 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 29/78621 with LDD structure or an extension or an offset region or characterised by the doping profile
• CPC Class Codes: H01L 29/78648 arranged on opposing sides of the channel
• 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: H01L 29/78696 characterised by the structure of the channel, e.g. multichannel, transverse or longitudinal shape, length or width, doping structure, or the overlap or alignment between the channel and the gate, the source or the drain, or the contacting structure of the channel H01L29/78612 takes precedence; transistors having a drain offset region or a lightly doped drain [LDD] H01L29/78621

Abstract

In a semiconductor device including an oxide semiconductor, a change in electrical characteristics is suppressed and reliability is improved. A miniaturized transistor including an oxide semiconductor is provided. A method for manufacturing a semiconductor device including an oxide semiconductor film includes the following steps: forming an oxide semiconductor film; forming an insulating film over the oxide semiconductor film; forming a conductive film over the insulating film; forming a first protective film over the conductive film; and forming a second protective film over the first protective film. The first protective film, the conductive film, and the insulating film are processed using the second protective film as a mask. After the second protective film is removed, the conductive film and the insulating film are processed using the first protective film as a mask to have a smaller area than that of the second protective film.

Claims

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

forming a semiconductor film;

forming an insulating film over the semiconductor film;

forming a conductive film over the insulating film;

forming a first protective film over the conductive film;

forming a second protective film over the first protective film;

processing the first protective film, the conductive film and the insulating film each using the second protective film as a mask;

removing the second protective film after processing using the second protective film as the mask; and

processing the conductive film and the insulating film each using the first protective film as a mask after removing the second protective film,

wherein each area of the conductive film and the insulating film after processing using the first protective film as the mask is smaller than an area of the second protective film at the time of processing using the second protective film as the mask.

2. The method for manufacturing a semiconductor device according to claim 1, wherein the area of the conductive film is greater than or equal to 15% and less than or equal to 50% of the area of the second protective film after processing using the first protective film as the mask.

3. The method for manufacturing a semiconductor device according to claim 1,

wherein the first protective film is formed using an inorganic material, and

wherein the second protective film is formed using an organic material.

4. The method for manufacturing a semiconductor device according to claim 1, wherein the conductive film comprises a metal oxide film and a metal film over the metal oxide film.

5. The method for manufacturing a semiconductor device according to claim 1, wherein the semiconductor film comprises an oxide semiconductor.

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

forming a semiconductor film;

forming an insulating film over the semiconductor film;

forming a conductive film over the insulating film;

forming a first protective film over the conductive film;

forming a second protective film over the first protective film;

processing the first protective film, the conductive film and the insulating film each using the second protective film as a mask;

removing the second protective film after processing using the second protective film as the mask;

processing the conductive film and the insulating film each using the first protective film as a mask after removing the second protective film;

performing plasma treatment on the semiconductor film from above the first protective film after processing using the first protective film as the mask;

removing the first protective film after the plasma treatment; and

forming a nitride insulating film over the conductive film and the semiconductor film after removing the first protective film,

wherein each area of the conductive film and the insulating film after processing using the first protective film as the mask is smaller than an area of the second protective film at the time of processing using the second protective film as the mask.

7. The method for manufacturing a semiconductor device according to claim 6, wherein the plasma treatment is performed under one or both of an argon atmosphere and a nitrogen atmosphere.

8. The method for manufacturing a semiconductor device according to claim 6, wherein the area of the conductive film is greater than or equal to 15% and less than or equal to 50% of the area of the second protective film after processing using the first protective film as the mask.

9. The method for manufacturing a semiconductor device according to claim 6,

wherein the first protective film is formed using an inorganic material, and

wherein the second protective film is formed using an organic material.

10. The method for manufacturing a semiconductor device according to claim 6, wherein the conductive film comprises a metal oxide film and a metal film over the metal oxide film.