Manufacturing method of semiconductor device

• US 8,664,097 B2
• Filed: 08/30/2011
• Issued: 03/04/2014
• Est. Priority Date: 09/13/2010
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Jintyou, Masami, Aihara, Yamato, Tochibayashi, Katsuaki, Arakawa, Toru
• Primary Examiner(s): Geyer, Scott B
• Application Number:
  US13/220,761
• Publication Number:
  US 20120064703A1
• Time in Patent Office: 917 Days
• Field of Search: None
• US Class Current: 438/488
• CPC Class Codes: H01L 21/0237 Materials
• 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 21/441 Deposition of conductive or insulating materials for electrodes
• CPC Class Codes: H01L 21/47573 Etching the layer
• CPC Class Codes: H01L 29/045 by their particular orientation of crystalline planes
• 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 29/45 Ohmic electrodes
• 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 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate

Abstract

An object is to provide a technique by which a semiconductor device including a high-performance and high-reliable transistor is manufactured. A protective conductive film which protects an oxide semiconductor layer when a wiring layer is formed from a conductive layer is formed between the oxide semiconductor layer and the conductive layer, and an etching process having two steps is performed. In a first etching step, an etching is performed under conditions that the protective conductive film is less etched than the conductive layer and the etching selectivity of the conductive layer to the protective conductive film is high. In a second etching step, etching is performed under conditions that the protective conductive film is more easily etched than the oxide semiconductor layer and the etching selectivity of the protective conductive film to the oxide semiconductor layer is high.

Claims

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

forming an oxide semiconductor layer wherein the oxide semiconductor layer comprises an oxide including crystals having c-axis alignment;

forming a protective conductive film over the oxide semiconductor layer;

forming a conductive layer over the protective conductive film;

selectively etching the conductive layer under a condition that the protective conductive film is less etched than the conductive layer, so that the protective conductive film is exposed; and

selectively etching the protective conductive film under a condition that the protective conductive film is more easily etched than the oxide semiconductor layer, so that the oxide semiconductor layer is exposed.

2. The manufacturing method of a semiconductor device according to claim 1, further comprising a step of forming an insulating film over the oxide semiconductor layer, the protective conductive film, and the conductive layer.

3. The manufacturing method of a semiconductor device according to claim 1, wherein a thickness of the protective conductive film is equal to or less than a thickness of the oxide semiconductor layer.

4. The manufacturing method of a semiconductor device according to claim 1, wherein the conductive layer has a stacked-layer structure including a film including aluminum as a material.

5. The manufacturing method of a semiconductor device according to claim 1, wherein the protective conductive film comprises a tungsten film.

6. The manufacturing method of a semiconductor device according to claim 1, wherein the oxide semiconductor layer comprises a film containing indium, gallium, and zinc.

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

forming a gate electrode layer;

forming a gate insulating film over the gate electrode layer;

forming an oxide semiconductor layer over the gate insulating film wherein the oxide semiconductor layer comprises an oxide including crystals having c-axis alignment;

forming a protective conductive film over the oxide semiconductor layer;

forming a conductive layer over the protective conductive film;

selectively etching the conductive layer under a condition that a first etching selectivity of the conductive layer to the protective conductive film is greater than 1, so that the protective conductive film is exposed; and

selectively etching the protective conductive film under a condition that a second etching selectivity of the protective conductive film to the oxide semiconductor layer is greater than 1, so that the oxide semiconductor layer is exposed.

8. The manufacturing method of a semiconductor device according to claim 7, further comprising a step of forming an insulating film over the oxide semiconductor layer, the protective conductive film, and the conductive layer.

9. The manufacturing method of a semiconductor device according to claim 7, wherein a thickness of the protective conductive film is equal to or less than a thickness of the oxide semiconductor layer.

10. The manufacturing method of a semiconductor device according to claim 7,

wherein the first etching selectivity of the conductive layer to the protective conductive film is greater than or equal to 4, and

wherein the second etching selectivity of the protective conductive film to the oxide semiconductor layer is greater than or equal to 30.

11. The manufacturing method of a semiconductor device according to claim 7, wherein the conductive layer has a stacked-layer structure including a film including aluminum as a material.

12. The manufacturing method of a semiconductor device according to claim 7, wherein the protective conductive film comprises a tungsten film.

13. The manufacturing method of a semiconductor device according to claim 7, wherein the oxide semiconductor layer comprises a film containing indium, gallium, and zinc.