Method for manufacturing semiconductor device

• US 10,170,633 B2
• Filed: 05/22/2017
• Issued: 01/01/2019
• Est. Priority Date: 01/12/2011
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei
• Primary Examiner(s): Galvin, III, Joseph
• Application Number:
  US15/601,301
• Publication Number:
  US 20170256646A1
• Time in Patent Office: 589 Days
• CPC Class Codes: H01L 29/41733 for thin film transistors with insulated gate
• 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

A transistor having an oxide semiconductor film in a channel formation region and a manufacturing method thereof are disclosed. The transistor is formed by the steps of: forming a base insulating over a substrate; forming an oxide semiconductor film over the base insulating film; forming a conductive film over the oxide semiconductor film; processing the conductive film to form a source electrode and a drain electrode; processing the oxide semiconductor film; forming a gate insulating film over the source electrode, the drain electrode, and the oxide semiconductor film; and forming a gate electrode over the gate insulating film. The aforementioned manufacturing method allows the formation of a transistor in which a side surface of the oxide semiconductor film is not in direct contact with bottom surfaces of the source electrode and the drain electrode, which contributes to the extremely small leak current of the transistor.

Claims

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

forming an oxide semiconductor film over a substrate;

forming a conductive film over the oxide semiconductor film;

heating the conductive film formed over the oxide semiconductor film;

forming a first resist mask over the conductive film;

etching the conductive film using the first resist mask to form a source electrode and a drain electrode;

forming a second resist mask over the oxide semiconductor film after etching the conductive film;

etching the oxide semiconductor film using the second resist mask,

forming a gate insulating film over the oxide semiconductor film; and

forming a gate electrode over the gate insulating film.

2. The method according to claim 1,

wherein the conductive film comprises W.

3. The method according to claim 1, further comprising the step of heating the substrate after forming the oxide semiconductor film and before forming the conductive film.

4. The method according to claim 1, further comprising the step of heating the substrate after forming the conductive film and before processing the conductive film.

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

forming a first oxide semiconductor film over a substrate;

forming a second oxide semiconductor film over the first oxide semiconductor film;

forming a conductive film over the second oxide semiconductor film;

heating the conductive film formed over the second oxide semiconductor film;

forming a first resist mask over the conductive film;

etching the conductive film using the first resist mask to form a source electrode and a drain electrode;

forming a second resist mask over the second oxide semiconductor film after etching the conductive film;

etching the second oxide semiconductor film using the second resist mask;

forming a gate insulating film over the second oxide semiconductor film; and

forming a gate electrode over the gate insulating film.

6. The method according to claim 5,

wherein the conductive film comprises W.

7. The method according to claim 5, further comprising the step of heating the substrate after forming the first oxide semiconductor film and before forming the conductive film.

8. The method according to claim 5, further comprising the step of heating the substrate after forming the conductive film and before processing the conductive film.