Method for manufacturing semiconductor device using oxide semiconductor

• US 9,142,679 B2
• Filed: 11/27/2012
• Issued: 09/22/2015
• Est. Priority Date: 12/02/2011
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei, Isobe, Atsuo, Ieda, Yoshinori, Nagai, Masaharu
• Primary Examiner(s): ARORA, AJAY
• Application Number:
  US13/686,281
• Publication Number:
  US 20130140554A1
• Time in Patent Office: 1,029 Days
• Field of Search: 438/149
• US Class Current: 1/1
• CPC Class Codes: H01L 29/41733 for thin film transistors with insulated gate
• 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 29/786 Thin film transistors, i.e. transistors with a channel being at least partly a thin film transistors having only the source or the drain region on an insulator layer H01L29/0653; thin film FinFETs H01L29/785
• 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 semiconductor device including a minute transistor with a short channel length is provided. A gate insulating layer is formed over a gate electrode layer; an oxide semiconductor layer is formed over the gate insulating layer; a first conductive layer and a second conductive layer are formed over the oxide semiconductor layer; a conductive film is formed over the first conductive layer and the second conductive layer; a resist mask is formed over the conductive film by performing electron beam exposure; and then a third conductive layer and a fourth conductive layer are formed over and in contact with the first conductive layer and the second conductive layer, respectively, by selectively etching the conductive film.

Claims

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

forming a gate insulating layer over a gate electrode layer;

forming an oxide semiconductor layer over the gate insulating layer;

forming a first conductive film over and in contact with the oxide semiconductor layer;

performing a light exposure using a photomask after forming the first conductive film;

forming first masks over the first conductive film after performing the light exposure;

forming a first conductive layer and a second conductive layer over the oxide semiconductor layer by selectively etching the first conductive film using the first masks;

forming a second conductive film over the first conductive layer and the second conductive layer after removing the first masks;

performing an electron beam exposure after forming the second conductive film;

forming a second mask over the second conductive film after performing the electron beam exposure; and

forming a third conductive layer over and in contact with the first conductive layer and a fourth conductive layer over and in contact with the second conductive layer by selectively etching the second conductive film using the second mask.

2. The method for manufacturing a semiconductor device according to claim 1, wherein a width of the oxide semiconductor layer in a channel length direction is larger than a width of the gate electrode layer in the channel length direction.

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

wherein a gap between the third conductive layer and the fourth conductive layer is determined by the electron beam exposure, and

wherein a gap between the first conductive layer and the second conductive layer is determined by the photomask.

4. The method for manufacturing a semiconductor device according to claim 1, wherein a channel length of the semiconductor device is equal to a gap between the third conductive layer and the fourth conductive layer.

5. The method for manufacturing a semiconductor device according to claim 1, wherein the second mask has one of a slit-like groove and a ring-like groove.

6. The method for manufacturing a semiconductor device according to claim 1, wherein the first masks and the second mask are resist masks.

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

forming a gate insulating layer over a gate electrode layer;

forming an oxide semiconductor layer over the gate insulating layer;

forming a first conductive film over and in contact with the oxide semiconductor layer;

performing an electron beam exposure after forming the first conductive film;

forming a first mask over the first conductive film after performing the electron beam exposure;

forming a first conductive layer and a second conductive layer over the oxide semiconductor layer by selectively etching the first conductive film using the first mask;

forming a second conductive film over the first conductive layer and the second conductive layer after removing the first mask;

performing a light exposure using a photomask after forming the second conductive film;

forming second masks over the second conductive film after performing the light exposure; and

forming a third conductive layer over and in contact with the first conductive layer and a fourth conductive layer over and in contact with the second conductive layer by selectively etching the second conductive film using the second masks.

8. The method for manufacturing a semiconductor device according to claim 7, wherein a width of the oxide semiconductor layer in a channel length direction is larger than a width of the gate electrode layer in the channel length direction.

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

wherein a gap between the first conductive layer and the second conductive layer is determined by the electron beam exposure, and

wherein a gap between the third conductive layer and the fourth conductive layer is determined by the photomask.

10. The method for manufacturing a semiconductor device according to claim 7, wherein an area of groove in the first mask is 5% of a total area of the first mask or less.

11. The method for manufacturing a semiconductor device according to claim 7, wherein the first mask has one of a slit-like groove and a ring-like groove.

12. The method for manufacturing a semiconductor device according to claim 7, wherein the first mask and the second masks are resist masks.

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

forming a first conductive film;

performing an electron beam exposure after forming the first conductive film;

forming a first mask over the first conductive film after performing the electron beam exposure;

forming a plurality of holes in the first conductive film by selectively etching the first conductive film using the first mask;

forming a second conductive film over the first conductive film after removing the first mask;

performing a light exposure using a photomask after forming the second conductive film;

forming second masks over the second conductive film after performing the light exposure; and

forming a first conductive layer and a second conductive layer by selectively etching the second conductive film using the second masks,

wherein the first conductive layer and the second conductive layer are over and in contact with a third conductive layer and a fourth conductive layer, respectively, and

wherein the third conductive layer and the fourth conductive layer are over and in contact with an oxide semiconductor layer.

14. The method for manufacturing a semiconductor device according to claim 13,

wherein a second gap between the first conductive layer and the second conductive layer is determined by the photomask, and

wherein a gap between the third conductive layer and the fourth conductive layer is determined by the electron beam exposure.

15. The method for manufacturing a semiconductor device according to claim 13, wherein an area where the electron beam exposure is performed is 5% of a total area of the first conductive film, or less.

16. The method for manufacturing a semiconductor device according to claim 13, wherein the first mask and the second masks are resist masks.

17. The method for manufacturing a semiconductor device according to claim 13,

wherein the first mask has a plurality of slit-like grooves,

wherein a narrow side of one of the plurality of slit-like grooves in the first mask has a first width, and

wherein the third conductive layer and the fourth conductive layer are separated with a gap substantially equal to the first width.