Plasma generating method

• US 10,615,005 B2
• Filed: 04/12/2019
• Issued: 04/07/2020
• Est. Priority Date: 04/12/2018
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Nagami, Koichi, Fujiwara, Kazunobu, Gondai, Tadashi, Yamada, Norikazu, Umehara, Naoyuki
• Primary Examiner(s): Taningco, Alexander H
• Assistant Examiner(s): Sathiraju, Srinivas
• Application Number:
  US16/382,586
• Publication Number:
  US 20190318915A1
• Time in Patent Office: 361 Days
• Field of Search: None
• CPC Class Codes: H01J 37/32091 the radio frequency energy being capacitively coupled to the plasma
• CPC Class Codes: H01J 37/32155 Frequency modulation
• CPC Class Codes: H01J 37/32183 Matching circuits
• CPC Class Codes: H01J 37/32577 Electrical connecting means
• CPC Class Codes: H01J 37/32935 Monitoring and controlling tubes by information coming from the object and/or discharge
• CPC Class Codes: H05H 1/46 using applied electromagnetic fields, e.g. high frequency or microwave energy H05H1/26 takes precedence
• CPC Class Codes: H05H 1/466 using capacitive coupling means, e.g. electrodes
• CPC Class Codes: H05H 2242/26 Matching networks

Abstract

In a method of an embodiment, radio-frequency power is supplied to an electrode via a matching device from a radio-frequency power supply in order to generate plasma within a chamber. During the supply of the radio-frequency power, it is determined whether or not plasma is generated within the chamber from one or more parameters reflecting plasma generation within the chamber. When it is determined that plasma is not generated, a frequency of the radio-frequency power output from the radio-frequency power supply is adjusted to set the load side reactance of the radio-frequency power supply to zero or to bring the load side reactance close to zero.

Claims

1. A plasma generating method comprising:

providing a plasma processing apparatus including a chamber;

a radio-frequency power supply;

an electrode electrically connected to the radio-frequency power supply to generate plasma within the chamber; and

a matching device provided between the radio-frequency power supply and the electrode in order to match a load side impedance of the radio-frequency power supply with an output impedance of the radio-frequency power supply, the matching device including a plurality of first series circuits connected in parallel to each other and each including a capacitor and a switching element connected to the capacitor in series, and a plurality of second series circuits connected in parallel to each other and each including a capacitor and a switching element connected to the capacitor in series;

supplying radio-frequency power to the electrode via the matching device from the radio-frequency power supply in order to generate plasma within the chamber;

determining whether or not plasma is generated within the chamber from one or more parameters reflecting plasma generation within the chamber during the supplying the radio-frequency power;

matching the load side impedance with the output impedance of the radio-frequency power by the matching device; and

when it is determined that plasma is not generated within the chamber in the determining, adjusting a frequency of the radio-frequency power output from the radio-frequency power supply so as to set the load side reactance of the radio-frequency power supply to zero or to bring the load side reactance close to zero.

2. The plasma generating method of claim 1, further comprising:

changing the frequency of the radio-frequency power output from the radio-frequency power supply and determining the frequency of the radio-frequency power that generates plasma within the chamber, when it is determined that plasma is not generated within the chamber from the one or more parameters after the adjusting the frequency of the radio-frequency power.

3. The plasma generating method of claim 2, wherein, in the changing the frequency of the radio-frequency power, the frequency is swept.

4. The plasma generating method of claim 2, wherein, in the changing the frequency of the radio-frequency power, the frequency is sequentially set to a plurality of frequencies.

5. The plasma generating method of claim 4, wherein the one or more parameters are one or more parameters selected from a peak value of a power of the radio-frequency power, a phase difference between a voltage and a current of the radio-frequency power, a magnitude of the load side impedance, a power level of a traveling wafer, a power level of a reflected wave, and a light emission amount within the chamber.

6. The plasma generating method of claim 1, wherein the one or more parameters are one or more parameters selected from a peak value of a power of the radio-frequency power, a phase difference between a voltage and a current of the radio-frequency power, a magnitude of the load side impedance, a power level of a traveling wafer, a power level of a reflected wave, and a light emission amount within the chamber.