Etching method, pattern forming process, thin-film transistor fabrication process, and etching solution

• US 7,960,289 B2
• Filed: 11/20/2007
• Issued: 06/14/2011
• Est. Priority Date: 12/05/2006
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Chang, Chienliu
• Primary Examiner(s): Ghyka; Alexander G
• Assistant Examiner(s): Chang; Leonard
• Application Number:
  US12/514,209
• Publication Number:
  US 20100035378A1
• Time in Patent Office: 1,302 Days
• Field of Search: 438/104, 438689-692, 438/745, 438/754, 257/E21.245, 257/E21.246
• US Class Current: 438/745
• CPC Class Codes: H01L 21/465 Chemical or electrical treatment, e.g. electrolytic etching to form insulating layers H01L21/469
• 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

An etching method is provided in which selective etching can be carried out for an amorphous oxide semiconductor film including at least one of gallium and zinc, and indium. In the etching method, the selective etching is performed using an alkaline etching solution. The alkaline etching solution contains especially ammonia in a specific concentration range.

Claims

1. An etching method for etching an amorphous oxide semiconductor film including indium and at least one of gallium, zinc or a combination of gallium and zinc;

the method comprising subjecting the amorphous oxide semiconductor film to selective etching relative to indium tin oxide (ITO) with an alkaline etching solution.

2. The etching method according to claim 1, wherein the amorphous oxide semiconductor film contains gallium, zinc and indium.

3. The etching method according to claim 1, wherein the etching solution contains ammonia in a concentration selected within the range of 4.6% by mass or more and 28% by mass or less.

4. A pattern forming process for forming a pattern of an amorphous oxide semiconductor;

the process comprising the steps of;

forming an amorphous oxide semiconductor film including indium and at least one of gallium, zinc, or a combination of gallium and zinc; and

subjecting the amorphous oxide semiconductor film to selective etching relative to indium tin oxide (ITO) with an alkaline etching solution.

5. The pattern forming process according to claim 4, wherein the amorphous oxide semiconductor film is formed on an oxide layer different in compositional ratio from the amorphous oxide semiconductor film.

6. The pattern forming process according to claim 4, wherein the amorphous oxide semiconductor film includes gallium, zinc and indium.

7. The pattern forming process according to claim 4, wherein the etching solution contains ammonia in a concentration selected within the range of 4.6% by mass or more and 28% by mass or less.

8. A thin-film transistor fabrication process comprising the step of forming source and drain electrodes, a gate electrode, a gate insulating layer and a semiconductor layer;

wherein the step of forming the semiconductor layer comprises the steps of;

forming an amorphous oxide semiconductor film including indium and at least one of gallium, zinc, or a combination of gallium and zinc; and

subjecting the amorphous oxide semiconductor film to selective etching relative to indium tin oxide (ITO) with an alkaline etching solution.

9. The thin-film transistor fabrication process according to claim 8, wherein the etching solution contains ammonia in a concentration selected within the range of 4.6% by mass or more and 28% by mass or less.