Plasma oxidation processing method

• US 7,989,364 B2
• Filed: 08/27/2007
• Issued: 08/02/2011
• Est. Priority Date: 08/28/2006
• Status: Active Grant

• Current Assignee: Nagoya University, Tokyo Electron Limited
• Original Assignee: Nagoya University, Tokyo Electron Limited
• Inventors: Hori, Masaru, Shiozawa, Toshihiko, Kabe, Yoshiro, Kitagawa, Junichi
• Primary Examiner(s): Sarkar; Asok K
• Application Number:
  US12/439,019
• Publication Number:
  US 20090263919A1
• Time in Patent Office: 1,436 Days
• Field of Search: 257/E21.282, 257/E21.283, 257/E21.301, 438/772, 438/787, 438/788
• US Class Current: 438/788
• CPC Class Codes: C23C 8/10 Oxidising
• CPC Class Codes: C23C 8/36 using ionised gases, e.g. ionitriding
• CPC Class Codes: H01L 21/02238 silicon in uncombined form, i.e. pure silicon
• CPC Class Codes: H01L 21/02252 formation by plasma treatment, e.g. plasma oxidation of the substrate after treatment of an insulating film by plasma H01L21/3105 and subgroups
• CPC Class Codes: H01L 21/31662 of silicon in uncombined form
• CPC Class Codes: H01L 22/20 Sequence of activities consisting of a plurality of measurements, corrections, marking or sorting steps

Abstract

A plasma oxidation process is performed to form a silicon oxide film on the surface of a target object by use of plasma with an O(¹D₂) radical density of 1×10¹² [cm⁻³] or more generated from a process gas containing oxygen inside a process chamber of a plasma processing apparatus. During the plasma oxidation process, the O(¹D₂) radical density in the plasma is measured by a VUV monochromator 63, and a correction is made to the plasma process conditions.

Claims

1. A plasma oxidation processing method comprising:

generating plasma with an O(¹D₂) radical density of 1×

10¹² [cm<sup>−

3</sup>] or more from a process gas containing O₂ gas and Ar gas inside a process chamber of a plasma processing apparatus; and

performing an oxidation process on a surface of a target object by the plasma,

wherein the plasma is generated from the process gas by microwaves supplied from a planar antenna including a plurality of slots into the process chamber,

the microwaves have a power of 0.97 to 2.67 W/cm²,

the plasma oxidation process uses a pressure of 1.33 to 334 Pa inside the process chamber, and

the process gas has an oxygen ratio of 0.2 to 1%, which is represented by a ratio of the O₂ gas in gas flow rate relative to the Ar gas.

2. The plasma oxidation processing method according to claim 1, wherein the oxidation process is performed on silicon of the surface of the target object to form a silicon oxide film.

3. The plasma oxidation processing method according to claim 2, wherein the plasma is used to oxidize a silicon surface exposed in a recessed portion formed on the target object, so as to form the silicon oxide film.

4. The plasma oxidation processing method according to claim 3, wherein the silicon oxide film is formed while a curved surface shape is formed on a silicon corner portion at an upper end of a sidewall of the recessed portion.

5. The plasma oxidation processing method according to claim 2, wherein the silicon is mono-crystalline silicon or poly-crystalline silicon.

6. The plasma oxidation processing method according to claim 1, wherein the process gas contains H₂ gas at a ratio of 0.01 to 1% in gas flow rate relative to the entire process gas.

7. The plasma oxidation processing method according to claim 1, wherein the power of the microwaves is 1.46 W/cm² or more.

8. The plasma oxidation processing method according to claim 1, wherein the process gas consists of O₂ gas and Ar gas or consists of O₂ gas, Ar gas, and H₂ gas with the H₂ gas set at a ratio of 0.01 to 1% in gas flow rate ratio relative to the entire process gas.

9. A plasma oxidation processing method comprising:

generating plasma by microwaves from a process gas containing O₂ gas and Ar gas inside a process chamber of a plasma processing apparatus;

measuring an O(¹D₂) radical density in the plasma;

performing an oxidation process on a target object by plasma with an O(¹D₂) radical density of 1×

10¹² [cm<sup>−

3</sup>] or more; and

making a correction to plasma generating conditions with reference to a measurement result of the O(¹D₂) radical density,

wherein the microwaves have a power of 0.97 to 2.67 W/cm²,

the plasma oxidation process uses a pressure of 1.33 to 334 Pa inside the process chamber, and

the process gas has an oxygen ratio of 0.2 to 1%, which is represented by a ratio of the O₂ gas in gas flow rate relative to the Ar gas.

10. The plasma oxidation processing method according to claim 9, wherein the process gas contains H₂ gas at a ratio of 0.01 to 1% in gas flow rate relative to the entire process gas.

11. The plasma oxidation processing method according to claim 9, wherein the microwaves are supplied from a planar antenna including a plurality of slots into the process chamber.

12. The plasma oxidation processing method according to claim 9, wherein the target object includes a silicon layer of mono-crystalline silicon or poly-crystalline silicon on a surface thereof, and the oxidation process is performed to oxidize the silicon layer to form a silicon oxide film thereon.

13. The plasma oxidation processing method according to claim 9, wherein the power of the microwaves is 1.46 W/cm² or more.

14. The plasma oxidation processing method according to claim 9, wherein the process gas consists of O₂ gas and Ar gas or consists of O₂ gas, Ar gas, and H₂ gas with the H₂ gas set at a ratio of 0.01 to 1% in gas flow rate ratio relative to the entire process gas.