METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE

• US 20110003428A1
• Filed: 06/29/2010
• Published: 01/06/2011
• Est. Priority Date: 06/30/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: YAMAZAKI, Shunpei, SASAKI, Toshinari, SAKATA, Junichiro, OHARA, Hiroki
• Granted Patent: US 8,216,878 B2
• Time in Patent Office: Days
• US Class Current: 438/104
• 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 27/124 with a particular composition, shape or layout of the wiring layers specially adapted to the circuit arrangement, e.g. scanning lines in LCD pixel circuits wiring structures per se H01L23/52
• CPC Class Codes: H01L 29/24 including, apart from doping materials or other impurities, only semiconductor materials not provided for in groups H01L29/16, H01L29/18, H01L29/20, H01L29/22 including organic materials H10K99/00
• CPC Class Codes: H01L 29/42356 Disposition, e.g. buried gate electrode H01L29/42324 and H01L29/4234 take precedence
• CPC Class Codes: H01L 29/42384 for thin film field effect transistors, e.g. characterised by the thickness or the shape of the insulator or the dimensions, the shape or the lay-out of the conductor
• 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 29/78606 with supplementary region or layer in the thin film or in the insulated bulk substrate supporting it for controlling or increasing the safety of the device H01L29/78642, H01L29/78645 take precedence
• CPC Class Codes: H01L 29/78618 characterised by the drain or the source properties, e.g. the doping structure, the composition, the sectional shape or the contact structure silicide contacts, electrodes in general H01L29/458
• 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

It is an object to provide a highly reliable semiconductor device which includes a thin film transistor having stable electric characteristics. It is another object to manufacture a highly reliable semiconductor device at lower cost with high productivity. In a method for manufacturing a semiconductor device which includes a thin film transistor where a semiconductor layer having a channel formation region, a source region, and a drain region are formed using an oxide semiconductor layer, heat treatment (heat treatment for dehydration or dehydrogenation) is performed so as to improve the purity of the oxide semiconductor layer and reduce impurities such as moisture. Moreover, the oxide semiconductor layer subjected to the heat treatment is slowly cooled under an oxygen atmosphere.

Claims

1. A method for manufacturing a semiconductor device comprising:

forming a gate electrode layer over a substrate having an insulating surface;

forming a gate insulating layer over the gate electrode layer;

forming a first oxide semiconductor film over the gate insulating layer;

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

heating the first oxide semiconductor film and the second oxide semiconductor film to be dehydrated or dehydrogenated;

then slowly cooling the first oxide semiconductor film and the second oxide semiconductor film in an oxygen atmosphere;

selectively etching the first oxide semiconductor film and the second oxide semiconductor film after the slowly cooling to form a first oxide semiconductor layer and a second oxide semiconductor layer;

forming a conductive film over the first oxide semiconductor layer and the second oxide semiconductor layer;

selectively etching the first oxide semiconductor layer, the second oxide semiconductor layer, and the conductive film to form a semiconductor layer, a source region, a drain region, a source electrode layer, and a drain electrode layer; and

forming an oxide insulating film which is contact with part of the semiconductor layer over the gate insulating layer, the semiconductor layer, the source region, the drain region, the source electrode layer, and the drain electrode layer so that carrier density is reduced.

2. The method for manufacturing a semiconductor device according to claim 1, wherein the second oxide semiconductor layer is formed into the source region and the drain region by the selectively etching for the first oxide semiconductor layer, the second oxide semiconductor layer, and the conductive film.

3. The method for manufacturing a semiconductor device according to claim 1, wherein the conductive film is formed into the source electrode layer and the drain electrode layer by the selectively etching for the first oxide semiconductor layer, the second oxide semiconductor layer, and the conductive film.

4. The method for manufacturing a semiconductor device according to claim 1, wherein the first oxide semiconductor layer is shaped into the semiconductor layer.

5. The method for manufacturing a semiconductor device according to claim 1, wherein the semiconductor device is incorporated into one selected from the group consisting of an electronic book reader, a television set, a digital photo frame, a portable amusement machine, a slot machine, a portable computer, and a cellular phone.

6. The method for manufacturing a semiconductor device according to claim 1, wherein the heating is conducted under an inert gas atmosphere.

7. The method for manufacturing a semiconductor device according to claim 6, wherein the inert gas atmosphere contains a gas selected from the group consisting of nitrogen, helium, neon and argon.

8. A method for manufacturing a semiconductor device comprising:

forming a gate electrode layer over a substrate having an insulating surface;

forming a gate insulating layer over the gate electrode layer;

forming a first oxide semiconductor film over the gate insulating layer;

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

heating the first oxide semiconductor film and the second oxide semiconductor film under an inert gas atmosphere so that carrier density is increased;

then slowly cooling the first oxide semiconductor film and the second oxide semiconductor film in an oxygen atmosphere;

selectively etching the first oxide semiconductor film and the second oxide semiconductor film after the slowly cooling to form a first oxide semiconductor layer and a second oxide semiconductor layer;

forming a conductive film over the first oxide semiconductor layer and the second oxide semiconductor layer;

selectively etching the first oxide semiconductor layer, the second oxide semiconductor layer, and the conductive film to form a semiconductor layer, a source region, a drain region, a source electrode layer, and a drain electrode layer; and

forming an oxide insulating film which is contact with part of the semiconductor layer over the gate insulating layer, the semiconductor layer, the source region, the drain region, the source electrode layer, and the drain electrode layer so that the carrier density is reduced.

9. The method for manufacturing a semiconductor device according to claim 8, wherein the inert gas atmosphere is a nitrogen atmosphere or a rare gas atmosphere.

10. The method for manufacturing a semiconductor device according to claim 8, wherein the first oxide semiconductor film and the second oxide semiconductor film are heated at 400°

C. or higher under an inert gas atmosphere.

11. The method for manufacturing a semiconductor device according to claim 8, wherein the first oxide semiconductor film and the second oxide semiconductor film are heated at 400°

C. or higher under an inert gas atmosphere and then slowly cooled to higher than or equal to room temperature and lower than 100°

C. under an oxygen atmosphere.

12. The method for manufacturing a semiconductor device according to claim 8, wherein the second oxide semiconductor layer is formed into the source region and the drain region by the selectively etching for the first oxide semiconductor layer, the second oxide semiconductor layer, and the conductive film.

13. The method for manufacturing a semiconductor device according to claim 8, wherein the conductive film is formed into the source electrode layer and the drain electrode layer by the selectively etching for the first oxide semiconductor layer, the second oxide semiconductor layer, and the conductive film.

14. The method for manufacturing a semiconductor device according to claim 8, wherein the first oxide semiconductor layer is shaped into the semiconductor layer.

15. The method for manufacturing a semiconductor device according to claim 8, wherein the semiconductor device is incorporated into one selected from the group consisting of an electronic book reader, a television set, a digital photo frame, a portable amusement machine, a slot machine, a portable computer, and a cellular phone.

16. A method for manufacturing a semiconductor device comprising:

forming a gate electrode layer over a substrate having an insulating surface;

forming a gate insulating layer over the gate electrode layer;

forming a first oxide semiconductor film over the gate insulating layer;

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

heating the first oxide semiconductor film and the second oxide semiconductor film under reduced pressure so that carrier density is increased;

then slowly cooling the first oxide semiconductor film and the second oxide semiconductor film in an oxygen atmosphere;

selectively etching the first oxide semiconductor film and the second oxide semiconductor film after the slowly cooling to form a first oxide semiconductor layer and a second oxide semiconductor layer;

forming a conductive film over the first oxide semiconductor layer and the second oxide semiconductor layer;

selectively etching the first oxide semiconductor layer, the second oxide semiconductor layer, and the conductive film to form a semiconductor layer, a source region, a drain region, a source electrode layer, and a drain electrode layer; and

forming an oxide insulating film which is contact with part of the semiconductor layer over the gate insulating layer, the semiconductor layer, the source region, the drain region, the source electrode layer, and the drain electrode layer so that the carrier density is reduced.

17. The method for manufacturing a semiconductor device according to claim 16, wherein a carrier density of the first oxide semiconductor layer whose carrier density is increased is 1×

10¹⁸/cm³ or higher.

18. The method for manufacturing a semiconductor device according to claim 16, wherein the second oxide semiconductor layer is formed into the source region and the drain region by the selectively etching for the first oxide semiconductor layer, the second oxide semiconductor layer, and the conductive film.

19. The method for manufacturing a semiconductor device according to claim 16, wherein the conductive film is formed into the source electrode layer and the drain electrode layer by the selectively etching for the first oxide semiconductor layer, the second oxide semiconductor layer, and the conductive film.

20. The method for manufacturing a semiconductor device according to claim 16, wherein the first oxide semiconductor layer is shaped into the semiconductor layer.

21. The method for manufacturing a semiconductor device according to claim 16, wherein the semiconductor device is incorporated into one selected from the group consisting of an electronic book reader, a television set, a digital photo frame, a portable amusement machine, a slot machine, a portable computer, and a cellular phone.

22. A method for manufacturing a semiconductor device comprising:

forming a first oxide semiconductor film over a substrate having an insulating surface;

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

heating the first oxide semiconductor film and the second oxide semiconductor film to be dehydrated or dehydrogenated;

then slowly cooling the first oxide semiconductor film and the second oxide semiconductor film in an oxygen atmosphere;

selectively etching the first oxide semiconductor film and the second oxide semiconductor film after the slowly cooling to form a first oxide semiconductor layer and a second oxide semiconductor layer;

forming a conductive film over the first oxide semiconductor layer and the second oxide semiconductor layer;

selectively etching the first oxide semiconductor layer, the second oxide semiconductor layer, and the conductive film to form a semiconductor layer, a source region, a drain region, a source electrode layer, and a drain electrode layer; and

forming an oxide insulating film which is contact with part of the semiconductor layer, the semiconductor layer, the source region, the drain region, the source electrode layer, and the drain electrode layer so that carrier density is reduced.

23. A method for manufacturing a semiconductor device comprising:

forming a first oxide semiconductor film over a substrate;

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

heating at least the first oxide semiconductor film to remove at least a portion of hydrogen contained in the first oxide semiconductor film;

cooling the first oxide semiconductor film in an oxygen atmosphere;

selectively etching the first oxide semiconductor film and the second oxide semiconductor film after the cooling to form a first oxide semiconductor layer and a second oxide semiconductor layer;

forming a conductive film over the first oxide semiconductor layer and the second oxide semiconductor layer;

selectively etching the first oxide semiconductor layer, the second oxide semiconductor layer, and the conductive film to form a semiconductor layer, a source region, a drain region, a source electrode layer, and a drain electrode layer; and

forming an oxide insulating film which is contact with part of the semiconductor layer, the semiconductor layer, the source region, the drain region, the source electrode layer, and the drain electrode layer so that carrier density is reduced.