Semiconductor device and method for manufacturing the same

• US 8,846,459 B2
• Filed: 10/16/2012
• Issued: 09/30/2014
• Est. Priority Date: 10/24/2011
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Tochibayashi, Katsuaki, Higano, Satoshi, Yamazaki, Shunpei
• Primary Examiner(s): Green, Telly
• Application Number:
  US13/652,708
• Publication Number:
  US 20130099233A1
• Time in Patent Office: 714 Days
• Field of Search: 438/104, 257/43, 257/E29.296, 257/E21.467, 257/E21.476, 257/52
• US Class Current: 438/142
• CPC Class Codes: H01L 21/02071 the processing being a delineation, e.g. RIE, of conductive layers
• CPC Class Codes: H01L 21/32136 using plasmas
• CPC Class Codes: H01L 21/465 Chemical or electrical treatment, e.g. electrolytic etching to form insulating layers H01L21/469
• CPC Class Codes: H01L 29/66742 Thin film unipolar transistors
• 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: H01L 29/78693 the semiconducting oxide being amorphous

Abstract

A highly reliable semiconductor device and a method for manufacturing the semiconductor device are provided. The semiconductor device is manufactured with a high yield to achieve high productivity. In the manufacture of a semiconductor device including a transistor in which a gate electrode layer, a gate insulating film, and an oxide semiconductor film are sequentially stacked and a source electrode layer and a drain electrode layer are provided in contact with the oxide semiconductor film, the source electrode layer and the drain electrode layer are formed through an etching step and then a step for removing impurities which are generated by the etching step and exist on a surface of the oxide semiconductor film and in the vicinity thereof is performed.

Claims

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

forming a gate electrode layer over an insulating surface;

forming a gate insulating film over the gate electrode layer;

forming an island-shaped oxide semiconductor film over the gate electrode layer with the gate insulating film interposed therebetween;

forming a conductive film over the gate insulating film and the island-shaped oxide semiconductor film;

processing the conductive film by plasma treatment using an etching gas containing a halogen element, so that a source electrode layer and a drain electrode layer are formed; and

performing impurity removal treatment on the island-shaped oxide semiconductor film to remove the halogen element contained in the etching gas,

wherein the impurity removal treatment includes oxygen plasma treatment or dinitrogen monoxide plasma treatment, and

wherein a surface of the island-shaped oxide semiconductor film on which the impurity removal treatment has been performed has a halogen concentration lower than or equal to 5×

10¹⁸ atoms/cm³.

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

wherein cleaning treatment using a dilute hydrofluoric acid solution is performed as the impurity removal treatment.

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

wherein, as the impurity removal treatment, oxygen plasma treatment or dinitrogen monoxide plasma treatment is performed and then cleaning treatment using a dilute hydrofluoric acid solution is performed.

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

forming a gate electrode layer over an insulating surface;

forming a gate insulating film over the gate electrode layer;

forming an island-shaped oxide semiconductor film over the gate electrode layer with the gate insulating film interposed therebetween;

forming a conductive film electrically connected to the island-shaped oxide semiconductor film;

processing the conductive film by plasma treatment using an etching gas containing a halogen element, so that a source electrode layer and a drain electrode layer are formed; and

performing impurity removal treatment on the island-shaped oxide semiconductor film to remove the halogen element contained in the etching gas,

wherein the impurity removal treatment includes oxygen plasma treatment or dinitrogen monoxide plasma treatment, and

wherein a surface of the island-shaped oxide semiconductor film on which the impurity removal treatment has been performed has a halogen concentration lower than or equal to 5×

10¹⁸ atoms/cm³.

5. The method for manufacturing a semiconductor device according to claim 4,

wherein cleaning treatment using a dilute hydrofluoric acid solution is performed as the impurity removal treatment.

6. The method for manufacturing a semiconductor device according to claim 4,

wherein, as the impurity removal treatment, oxygen plasma treatment or dinitrogen monoxide plasma treatment is performed and then cleaning treatment using a dilute hydrofluoric acid solution is performed.