MANUFACTURING METHOD OF FIN-TYPE FIELD EFFECT TRANSISTOR

• US 20080171407A1
• Filed: 01/11/2008
• Published: 07/17/2008
• Est. Priority Date: 01/17/2007
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Kobayashi, Takashi, Kitagawa, Junichi, Tanaka, Yoshitsugu, Nakabayashi, Hajime, Sugawara, Takuya
• Granted Patent: US 7,955,922 B2
• Time in Patent Office: Days
• US Class Current: 438/151
• CPC Class Codes: H01L 29/66818 the channel being thinned after patterning, e.g. sacrificial oxidation on fin

Abstract

A method for manufacturing a fin-type field effect transistor simply and securely by using a SOI (Silicon On Insulator) wafer, capable of suppressing an undercut formation, is disclosed. The method includes forming a fin-shaped protrusion by selectively dry-etching a single crystalline silicon layer until an underlying buried oxide layer is exposed; forming a sacrificial oxide film by oxidizing a surface of the protrusion including a damage inflicted thereon; and forming a fin having a clean surface by removing the sacrificial oxide film by etching, wherein an etching rate r₁ of the sacrificial oxide film is higher than an etching rate r₂ of the buried oxide layer during the etching.

Claims

1. A method for manufacturing a fin-type field effect transistor by using a SOI (Silicon On Insulator) wafer including, on a Si substrate, a buried oxide layer made of an insulating material and a single crystalline silicon layer formed thereon, the method comprising:

forming a fin-shaped protrusion by selectively dry-etching the single crystalline silicon layer until the underlying buried oxide layer is exposed;

forming a sacrificial oxide film by oxidizing a surface of the protrusion including a damage inflicted thereon; and

forming a fin having a clean surface by removing the sacrificial oxide film by etching,

wherein an etching rate r₁ of the sacrificial oxide film is higher than an etching rate r₂ of the buried oxide layer during the etching.

2. The method of claim 1, wherein the sacrificial oxide film is formed through a plasma oxidation process.

3. The method of claim 1, wherein the sacrificial oxide film is formed through a plasma oxidation process of a RLSA (Radial Line Slot Antenna) microwave plasma type.

4. The method of claim 3, wherein a processing gas containing a rare gas and an oxygen gas is used in the plasma process of the RLSA microwave plasma type.

5. The method of claim 4, wherein the processing gas containing an argon gas and an oxygen gas is used in the plasma process of the RLSA microwave plasma type.

6. The method of claim 3, wherein a processing gas containing an argon gas, an oxygen gas and a hydrogen gas is used in the plasma process of the RLSA microwave plasma type.

7. The method of claim 3, wherein a processing temperature is about 300 to 600°

C. in the plasma process of the RLSA microwave plasma type.

8. The method of claim 3, wherein a processing temperature is about 400 to 500°

C. in the plasma process of the RLSA microwave plasma type.

9. The method of claim 1, wherein an etching rate ratio r₁/r₂ between the etching rate of the sacrificial oxide film and the etching rate of the buried oxide layer is greater than or equal to about 1.2.

10. The method of claim 1, wherein the sacrificial oxide film is removed by wet etching.

11. The method of claim 10, wherein hydrofluoric acid is used as an etching solution for the wet etching.

12. A method for manufacturing a fin-type field effect transistor by using a SOI wafer including, on a Si substrate, a buried oxide layer made of an insulating material and a single crystalline silicon layer formed thereon, the method comprising:

forming a fin-shaped protrusion by selectively dry-etching the single crystalline silicon layer until the underlying buried oxide layer is exposed;

forming a sacrificial oxide film by oxidizing a surface of the protrusion including a damage inflicted thereon; and

forming a fin having a clean surface by removing the sacrificial oxide film by wet etching,

wherein an etching rate of the sacrificial oxide film is higher than an etching rate of the buried oxide layer for an etching solution used in the wet etching.