PLASMA PROCESSING METHOD AND PLASMA PROCESSING APPARATUS

• US 20070227665A1
• Filed: 03/30/2007
• Published: 10/04/2007
• Est. Priority Date: 03/30/2006
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Koshimizu, Chishio, Iwata, Manabu, Tanaka, Satoshi, Matsumoto, Naoki
• Granted Patent: US 7,829,463 B2
• Time in Patent Office: Days
• US Class Current: 156/345.470
• CPC Class Codes: H01J 37/32091 the radio frequency energy being capacitively coupled to the plasma
• CPC Class Codes: H01J 37/32174 Circuits specially adapted for controlling the RF discharge
• CPC Class Codes: H01J 37/32623 Mechanical discharge control means
• CPC Class Codes: H01J 37/32706 Polarising the substrate
• CPC Class Codes: H01J 37/32935 Monitoring and controlling tubes by information coming from the object and/or discharge
• CPC Class Codes: H01L 21/31116 by dry-etching

Abstract

A plasma processing method performs a desired plasma process on substrates by using a plasma generated in a processing space. A first and a second electrode are disposed in parallel in a processing vessel that is grounded, the substrate is supported on the second electrode to face the first electrode, the processing vessel is vacuum evacuated, a desired processing gas is supplied into the processing space formed between the first electrode, the second electrode and a sidewall of the processing vessel, and a first radio frequency power is supplied to the second electrode. The first electrode is connected to the processing vessel via an insulator or a space, and is electrically coupled to a ground potential via a capacitance varying unit whose electrostatic capacitance is varied based on a process condition of the plasma process performed on the substrate.

Claims

1. A plasma processing method for performing a desired plasma process on substrates by using a plasma generated in a processing space,

wherein a first and a second electrode are disposed in parallel to each other with a specific interval in a processing vessel that is grounded and capable of being vacuum evacuated, the substrate is supported on the second electrode to face the first electrode, the processing vessel is vacuum evacuated to a specific pressure level, a desired processing gas is supplied into the processing space formed between the first electrode, the second electrode and a sidewall of the processing vessel, and a first radio frequency power is supplied to the second electrode to generate the plasma in the processing space, and

wherein the first electrode is connected to the processing vessel via an insulator or a space, and is electrically coupled to a ground potential via a capacitance varying unit whose electrostatic capacitance is variable, and the electrostatic capacitance of the capacitance varying unit is controlled based on a process condition of the plasma process performed on the substrate.

2. The plasma processing method of claim 1, wherein, in a process in which a deposit film is easily attached to the first electrode, the electrostatic capacitance of the capacitance varying unit is set to be high;

and, in a process in which a deposit film is not easily attached to the first electrode, the electrostatic capacitance of the capacitance varying unit is set to be low.

3. The plasma processing method of claim 1, wherein, in a multi-step process including a plurality of steps, the electrostatic capacitance of the capacitance varying unit is set to be high during all of the steps except a final step of the multi-step process;

and the electrostatic capacitance of the variable capacitor is set to be low during the final step.

4. The plasma processing method of claim 1, wherein the capacitance varying unit includes a variable capacitor.

5. The plasma processing method of claim 1, wherein a second radio frequency power, whose frequency is lower than that of the first radio frequency power, is applied to the second electrode.

6. The plasma processing method of claim 1, wherein a DC voltage is controllably applied to the first electrode.

7. A plasma processing apparatus comprising:

a processing vessel that is grounded and capable of being vacuum evacuated;

a first electrode connected to the processing vessel via an insulator or a space;

a capacitance varying unit whose electrostatic capacitance is variable, electrically connected between the first electrode and a ground potential;

a second electrode disposed in the processing vessel to be in parallel to the first electrode with a specific interval, for supporting a target substrate thereon to face the first electrode;

a processing gas supply unit for supplying a processing gas into a processing space between the first electrode, the second electrode and a sidewall of the processing vessel;

a first radio frequency power supply unit for applying a first radio frequency power to the second electrode to generate a plasma of the processing gas in the processing space; and

a capacitance control unit for controlling the electrostatic capacitance of the capacitance varying unit based on a process condition of a plasma process performed on the substrate.

8. The plasma processing apparatus of claim 7, wherein the capacitance control unit sets the electrostatic capacitance of the capacitance varying unit to be high in a process in which a deposit film is easily attached to the first electrode, and to be low in a process in which a deposit film is not easily attached to the first electrode.

9. The plasma processing apparatus of claim 7, wherein, in a multi-step process including a plurality of steps, the capacitance control unit sets the electrostatic capacitance of the capacitance varying unit to be high during all of the steps except a final step of the multi-step process, and to be low during the final step.

10. The plasma processing apparatus of claim 7, wherein the capacitance varying unit includes a variable capacitor.

11. The plasma processing apparatus of claim 7, further comprising:

a second radio frequency power supply unit for applying a second radio frequency power, whose frequency is lower than that of the first radio frequency power, to the second electrode.

12. The plasma processing apparatus of claim 7, further comprising:

a DC power supply for controllably applying a DC voltage to the first electrode.

13. A plasma processing method for performing a desired plasma process on substrates by using a plasma generated in a processing space,

wherein a first and a second electrode are disposed in parallel to each other with a specific interval in a processing vessel that is grounded and capable of being vacuum evacuated, the substrate is supported on the second electrode to face the first electrode, the processing vessel is vacuum evacuated to a specific pressure level, a desired processing gas is supplied into the processing space formed between the first electrode, the second electrode and a sidewall of the processing vessel, and a first radio frequency power is supplied to the second electrode to generate the plasma in the processing space, and

wherein the first electrode is connected to the processing vessel via an insulator or a space, and is electrically coupled to a ground potential via a capacitance varying unit whose electrostatic capacitance is variable, and the electrostatic capacitance of the capacitance varying unit is controlled based on the number of substrates on which the plasma process is performed.

14. The plasma processing method of claim 13, wherein the electrostatic capacitance of the capacitance varying unit is set to be high in advance, and reduced as the number of substrates on which the plasma process is performed increases.

15. A plasma processing apparatus comprising:

a processing vessel that is grounded and capable of being vacuum evacuated;

a first electrode connected to the processing vessel via an insulator or a space;

a capacitance varying unit whose electrostatic capacitance is variable, electrically connected between the first electrode and a ground potential;

a second electrode disposed in the processing vessel to be in parallel to the first electrode with a specific interval, for supporting a target substrate thereon to face the first electrode;

a processing gas supply unit for supplying a processing gas into a processing space between the first electrode, the second electrode and a sidewall of the processing vessel;

a first radio frequency power supply unit for applying a first radio frequency power to the second electrode to generate a plasma of the processing gas in the processing space; and

a capacitance control unit for controlling the electrostatic capacitance of the capacitance varying unit based on the number of substrates on which the plasma process is performed.

16. The plasma processing apparatus of claim 15, wherein the capacitance control unit sets the electrostatic capacitance of the capacitance varying unit to be high in advance, and to be reduced as the number of substrates on which the plasma process is performed increases.