Method for manufacturing semiconductor device

• US 8,790,960 B2
• Filed: 04/13/2011
• Issued: 07/29/2014
• Est. Priority Date: 04/28/2010
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei
• Primary Examiner(s): MULPURI, SAVITRI
• Application Number:
  US13/085,812
• Publication Number:
  US 20110269266A1
• Time in Patent Office: 1,203 Days
• Field of Search: 438/104, 438149-158
• US Class Current: 438/104
• CPC Class Codes: H01L 21/02554 Oxides
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/02631 Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation
• CPC Class Codes: H01L 21/02664 Aftertreatments planarisation in general H01L21/304
• CPC Class Codes: H01L 21/465 Chemical or electrical treatment, e.g. electrolytic etching to form insulating layers H01L21/469
• 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 29/4908 for thin film semiconductor, e.g. gate of TFT
• 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 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate

Abstract

A semiconductor device including an oxide semiconductor with stable electric characteristics and high reliability is provided. An island-shaped oxide semiconductor layer is formed by using a resist mask, the resist mask is removed, oxygen is introduced (added) to the oxide semiconductor layer, and heat treatment is performed. The removal of the resist mask, introduction of the oxygen, and heat treatment are performed successively without exposure to the air. Through the oxygen introduction and heat treatment, impurities such as hydrogen, moisture, a hydroxyl group, or hydride are intentionally removed from the oxide semiconductor layer, whereby the oxide semiconductor layer is highly purified. Chlorine may be introduced to an insulating layer over which the oxide semiconductor layer is formed before formation of the oxide semiconductor layer. By introducing chlorine, hydrogen in the insulating layer can be fixed, thereby preventing diffusion of hydrogen from the insulating layer into the oxide semiconductor layer.

Claims

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

forming a cap layer over an oxide semiconductor layer;

forming a resist mask over the cap layer;

forming an island-shaped oxide semiconductor layer and an island-shaped cap layer by using the resist mask;

removing the resist mask;

introducing oxygen to the island-shaped oxide semiconductor layer through the island-shaped cap layer;

performing a heat treatment on the island-shaped oxide semiconductor layer; and

etching the island-shaped cap layer to form a channel protective layer after performing the heat treatment.

3. The method for manufacturing a semiconductor device according to claim 1, wherein the oxide semiconductor layer comprises In and Ga.

4. The method for manufacturing a semiconductor device according to claim 1, wherein the oxygen introduced to the island-shaped oxide semiconductor layer comprises an oxygen radical or an oxygen ion.

5. The method for manufacturing a semiconductor device according to claim 1, wherein the step of removing the resist mask, the step of introducing oxygen to the island-shaped oxide semiconductor layer, and the step of performing the heat treatment on the island-shaped oxide semiconductor layer are performed in a reduced pressure atmosphere, an inert gas atmosphere, or an oxygen gas atmosphere.

6. The method for manufacturing a semiconductor device according to claim 1, wherein the step of removing the resist mask, the step of introducing oxygen to the island-shaped oxide semiconductor layer, and the step of performing the heat treatment on the island-shaped oxide semiconductor layer are successively performed without exposure to air.

2. The method for manufacturing a semiconductor device according to claim , wherein the cap layer comprises gallium oxide.

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

forming a cap layer over an oxide semiconductor layer;

forming a resist mask over the cap layer;

forming an island-shaped oxide semiconductor layer and an island-shaped cap layer by using the resist mask so that a side surface of the island-shaped cap layer is aligned with a side surface of the island-shaped oxide semiconductor layer;

removing the resist mask;

introducing oxygen to the island-shaped oxide semiconductor layer through the island-shaped cap layer;

performing a heat treatment on the island-shaped oxide semiconductor layer; and

etching the island-shaped cap layer to form a channel protective layer after performing the heat treatment.

8. The method for manufacturing a semiconductor device according to claim 7, wherein the cap layer comprises gallium oxide.

9. The method for manufacturing a semiconductor device according to claim 7, wherein the oxide semiconductor layer comprises In and Ga.

10. The method for manufacturing a semiconductor device according to claim 7, wherein the oxygen introduced to the island-shaped oxide semiconductor layer comprises an oxygen radical or an oxygen ion.

11. The method for manufacturing a semiconductor device according to claim 7, wherein the step of removing the resist mask, the step of introducing oxygen to the island-shaped oxide semiconductor layer, and the step of performing the heat treatment on the island-shaped oxide semiconductor layer are performed in a reduced pressure atmosphere, an inert gas atmosphere, or an oxygen gas atmosphere.

12. The method for manufacturing a semiconductor device according to claim 7, wherein the step of removing the resist mask, the step of introducing oxygen to the island-shaped oxide semiconductor layer, and the step of performing the heat treatment on the island-shaped oxide semiconductor layer are successively performed without exposure to air.