Plasma processing apparatus and method

• US 7,951,262 B2
• Filed: 06/21/2005
• Issued: 05/31/2011
• Est. Priority Date: 06/21/2004
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Koshiishi, Akira, Yano, Daisuke, Hinata, Kunihiko, Kobayashi, Noriyuki, Matsumoto, Naoki, Saito, Masashi, Yamazaki, Hiroki, Sugimoto, Masaru, Ohtani, Ryuji, Kibi, Kazuo, Hanaoka, Hidetoshi, Hayami, Toshihiro, Koshimizu, Chishio, Iwata, Manabu, Yamazawa, Yohei, Sato, Manabu
• Primary Examiner(s): Chen; Keath T
• Application Number:
  US11/156,561
• Publication Number:
  US 20060037703A1
• Time in Patent Office: 2,170 Days
• Field of Search: 156/345.44
• US Class Current: 156/345.44
• CPC Class Codes: H01J 2237/334 Etching
• CPC Class Codes: H01J 37/32082 Radio frequency generated discharge H01J37/32357, H01J37/32366, H01J37/32394 and H01J37/32403 take precedence
• 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 37/3244 Gas supply means
• CPC Class Codes: H01J 37/32697 Electrostatic control
• CPC Class Codes: H01J 37/32706 Polarising the substrate
• CPC Class Codes: H01L 21/3065 Plasma etching; Reactive-ion etching

Abstract

An apparatus includes an upper electrode and a lower electrode for supporting a wafer disposed opposite each other within a process chamber. A first RF power supply configured to apply a first RF power having a relatively higher frequency, and a second RF power supply configured to apply a second RF power having a relatively lower frequency is connected to the lower electrode. A variable DC power supply is connected to the upper electrode. A process gas is supplied into the process chamber to generate plasma of the process gas so as to perform plasma etching.

Claims

1. A plasma processing apparatus comprising:

a process container that forms a process space to accommodate a target substrate;

an exhaust unit connected to an exhaust port of the process container to vacuum-exhaust gas from inside the process container;

an exhaust plate interposed between the process space and the exhaust port to rectify a flow of exhaust gas;

a first electrode and a second electrode disposed opposite each other within the process container, the first electrode being an upper electrode and the second electrode being a lower electrode configured to support the target substrate through a mount face;

an electrode support made of an insulating material and including a first portion interposed between the second electrode and a bottom of the process container and a second portion surrounding the second electrode;

a first RF power application unit configured to apply a first RF power to the second electrode;

a second RF power application unit configured to apply a second RF power to the second electrode, the second RF power having a frequency lower than that of the first RF power;

a DC power supply configured to apply a DC voltage to the first electrode;

a process gas supply unit configured to supply a process gas into the process container;

a first shield part covering a side surface of the electrode support and formed of a first conductive internal body and a first insulator covering the first conductive internal body; and

a conductive member disposed within the process container and grounded to release through plasma a current caused by the DC voltage applied from the DC power supply to the first electrode, the conductive member being supported by the first shield part and laterally protruding therefrom at a position between the mount face and the exhaust plate so as for the conductive member to be exposed to the plasma, and the conductive member being grounded through the first conductive internal body of the first shield part.

2. The plasma processing apparatus according to claim 1, wherein the DC power supply is configured such that any one of application voltage, application current, and application power to the first electrode is variable.

3. The plasma processing apparatus according to claim 1, further comprising a control unit configured to control any one of application voltage, application current, and application power from the DC power supply to the first electrode.

4. The plasma processing apparatus according to claim 3, wherein the control unit is configured to control whether the DC voltage is to be applied or not, from the DC power supply to the first electrode.

5. The plasma processing apparatus according to claim 3, further comprising a detector configured to detect a generated plasma state, wherein the control unit controls any one of application voltage, application current, and application power from the DC power supply to the first electrode, based on information from the detector.

6. The plasma processing apparatus according to claim 1, wherein the first RF power applied to the second electrode has a frequency of 27 MHz or more.

7. The plasma processing apparatus according to claim 6, wherein the first RF power applied to the second electrode has a frequency of 40 MHz or more.

8. The plasma processing apparatus according to claim 1, wherein the second RF power applied to the second electrode has a frequency of 13.56 MHz or less.

9. The plasma processing apparatus according to claim 1, wherein the DC power supply is configured to apply a voltage within a range of −

2,000 to +1,000V.

10. The plasma processing apparatus according to claim 1, wherein a surface of the first electrode facing the second electrode is made of a silicon-containing substance.

11. The plasma processing apparatus according to claim 1, wherein the first electrode is in a floating state relative to a ground potential in a sense of DC.

12. The plasma processing apparatus according to claim 11, further comprising a changeover device configured to change over the first electrode between the floating state and a grounded state, wherein, based on a command from an overall control unit, the changeover device sets the first electrode in the floating state relative to a ground potential when the DC voltage is applied to the first electrode, and the changeover device sets the first electrode in the floating state or the grounded state relative to the ground potential when the DC voltage is not applied to the first electrode.

13. The plasma processing apparatus according to claim 1, wherein the conductive member has a recess to prevent flying substances from being deposited during a plasma process.

14. The plasma processing apparatus according to claim 1, wherein a cover plate is disposed to partly cover the conductive member, and the cover plate is moved relative to the conductive member by a driving mechanism to change a portion of the conductive member to be exposed to plasma.

15. The plasma processing apparatus according to claim 1, wherein the conductive member is columnar and partly exposed to plasma, and the conductive member is rotated about a center thereof by a driving mechanism to change a portion of the conductive member to be exposed to plasma.

16. The plasma processing apparatus according to claim 1, wherein a cover film having a stepped shape and made of a material to be etched by plasma is disposed to partly cover the conductive member, and the cover film is configured to be etched to change a portion of the conductive member to be exposed to plasma.

17. The plasma processing apparatus according to claim 1, wherein an electrostatic chuck configured to hold the target substrate by an electrostatic attraction force is disposed on the second electrode, and the mount face is defined by the electrostatic chuck.

18. The plasma processing apparatus according to claim 1, wherein the exhaust plate is covered with an insulator present on its surface.

19. The plasma processing apparatus according to claim 1, wherein the apparatus further comprises a second shield part covering an inner sidewall of the process container and including a second insulator covering a surface of the second shield part.

20. The plasma processing apparatus according to claim 19, wherein the second shield part is formed of a second conductive internal body and the second insulator covering the second conductive internal body.

21. The plasma processing apparatus according to claim 20, wherein the first and second conductive internal bodies are made of aluminum and the first and second insulators are made of ceramic.