Manufacturing method of semiconductor device

• US 8,536,571 B2
• Filed: 01/09/2012
• Issued: 09/17/2013
• Est. Priority Date: 01/12/2011
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei
• Primary Examiner(s): Smith, Zandra
• Assistant Examiner(s): PATTON, PAUL E
• Application Number:
  US13/346,072
• Publication Number:
  US 20120175610A1
• Time in Patent Office: 617 Days
• Field of Search: 257/43, 257/E29.296, 257/E21.46, 438/104
• US Class Current: 257/43
• CPC Class Codes: H01L 21/477 Thermal treatment for modifying the properties of semiconductor bodies, e.g. annealing, sintering H01L21/38 - H01L21/449 and H01L21/461 - H01L21/475 take precedence
• 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

Abstract

A manufacturing method of a semiconductor device includes the steps of: forming a gate electrode over a substrate; forming a gate insulating film over the gate electrode; forming an oxide semiconductor film; performing heat treatment to form a second oxide semiconductor film after the step of forming the first oxide semiconductor film; forming a first conductive film; forming a first resist mask including regions whose thicknesses are different; etching the second oxide semiconductor film and the first conductive film using the first resist mask to form a third oxide semiconductor film and a second conductive film; reducing the size of the first resist mask to form a second resist mask; selectively etching the second conductive film using the second resist mask to remove a part of the second conductive film so that a source electrode and a drain electrode are formed.

Claims

1. A semiconductor device comprising:

a gate electrode;

a first insulating film over the gate electrode;

an oxide semiconductor layer over the gate electrode with the first insulating film interposed therebetween; and

a first electrode and a second electrode over the oxide semiconductor layer,

wherein the first electrode and the second electrode are provided inside an upper end of the oxide semiconductor layer when seen from the above.

2. The semiconductor device according to claim 1, wherein the second electrode is provided between parts of the first electrode when seen from the above.

3. The semiconductor device according to claim 1, further comprising a second insulating film over the gate electrode with the gate electrode, the first insulating film, and the oxide semiconductor layer interposed therebetween, wherein the first electrode and the second electrode are provided over the second insulating film.

4. The semiconductor device according to claim 1, wherein the oxide semiconductor layer comprises indium, gallium, and zinc.

5. The semiconductor device according to claim 1, wherein the oxide semiconductor layer is amorphous.

6. The semiconductor device according to claim 1, wherein the oxide semiconductor layer comprise a crystalline region.

7. The semiconductor device according to claim 1, wherein the oxide semiconductor layer partly overlaps with an end of the gate electrode.

8. The semiconductor device according to claim 1, wherein the first electrode and the second electrode partly overlap with an end of the gate electrode.

9. A semiconductor device comprising:

a gate electrode;

a first insulating film over the gate electrode;

an oxide semiconductor layer over the gate electrode with the first insulating film interposed therebetween; and

a first electrode and a second electrode on and in contact with the oxide semiconductor layer,

wherein the first electrode and the second electrode are provided inside an upper end of the oxide semiconductor layer when seen from the above.

10. The semiconductor device according to claim 9, wherein the second electrode is provided between parts of the first electrode when seen from the above.

11. The semiconductor device according to claim 9, further comprising a second insulating film over the gate electrode with the gate electrode, the first insulating film, and the oxide semiconductor layer interposed therebetween, wherein the first electrode and the second electrode are provided over the second insulating film.

12. The semiconductor device according to claim 9, wherein the oxide semiconductor layer comprises indium, gallium, and zinc.

13. The semiconductor device according to claim 9, wherein the oxide semiconductor layer is amorphous.

14. The semiconductor device according to claim 9, wherein the oxide semiconductor layer comprise a crystalline region.

15. The semiconductor device according to claim 9, wherein the oxide semiconductor layer partly overlaps with an end of the gate electrode.

16. The semiconductor device according to claim 9, wherein the first electrode and the second electrode partly overlap with an end of the gate electrode.

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

forming a gate electrode over a substrate;

forming a first insulating film over the gate electrode;

forming an oxide semiconductor film over the first insulating film;

forming a first conductive film over the oxide semiconductor film;

forming an oxide semiconductor layer and a second conductive film by etching the oxide semiconductor film and the first conductive film; and

forming a first electrode and a second electrode by etching the second conductive film so as to be inside an upper end of the oxide semiconductor layer when seen from the above.

18. The method for manufacturing a semiconductor device according to claim 17, further comprising the steps of

forming a first resist mask over the first conductive film, wherein the first resist mask has a depression which overlaps with the gate electrode;

and

forming a second resist mask and a third resist mask by removing the first resist mask,

wherein the oxide semiconductor layer and the second conductive film are formed by etching the oxide semiconductor film and the first conductive film using the first resist mask, and

wherein the first electrode and the second electrode are formed by etching the second conductive film using the second resist mask and the third resist mask.

19. The method for manufacturing a semiconductor device according to claim 17, further comprising the step of heating the oxide semiconductor film at a temperature of higher than or equal to 150°

C. and lower than a strain point of the substrate.

20. The method for manufacturing a semiconductor device according to claim 17, further comprising the step of heating the oxide semiconductor layer at a temperature of higher than or equal to 150°

C. and lower than or equal to 450°

C.

21. The method for manufacturing a semiconductor device according to claim 17, wherein the first electrode and the second electrode are formed so as to be in contact with the oxide semiconductor layer only on an upper surface of the oxide semiconductor layer.

22. The method for manufacturing a semiconductor device according to claim 17, wherein the oxide semiconductor layer comprises indium, gallium, and zinc.

23. The method for manufacturing a semiconductor device according to claim 17, wherein the oxide semiconductor layer is amorphous.

24. The method for manufacturing a semiconductor device according to claim 17, wherein the oxide semiconductor layer comprises a crystalline region.