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US-12620563-B2 - Plasma processing apparatus and plasma processing method

US12620563B2US 12620563 B2US12620563 B2US 12620563B2US-12620563-B2

Abstract

There is provided a technique capable of improving plasma uniformity in a parallel plate-type plasma processing apparatus having a plasma excitation frequency of a VHF band or an UHF band. A plasma processing apparatus according to an exemplary embodiment includes a process container, a stage provided in the process container, a dielectric plate provided above the upper surface of the stage via a space in the process container, and an upper electrode provided above the dielectric plate. An gap is provided between the upper electrode and the dielectric plate, and the width of the gap is non-uniform in a direction in which the dielectric plate extends.

Inventors

  • Masaki Hirayama

Assignees

  • TOKYO ELECTRON LIMITED
  • TOHOKU UNIVERSITY

Dates

Publication Date
20260505
Application Date
20191126
Priority Date
20181206

Claims (17)

  1. 1 . A plasma processing apparatus comprising: a process container; a stage provided in the process container; a dielectric plate provided above the stage via a space in the process container; an upper electrode provided above the dielectric plate; a waveguide that guides a high frequency of a VHF band or an UHF band; an end portion of the waveguide that is located toward the space and radiates the high frequency into the space; and a dielectric rod interposed between the upper electrode and the dielectric plate and extending along a central axial line of the process container, wherein a gap is provided between the upper electrode and the dielectric plate, wherein a width of the gap is non-uniform in a direction in which the dielectric plate extends, and wherein the gap is defined by separating the upper electrode and the dielectric plate from each other in a state where the end portion of the upper electrode and the end portion of the dielectric plate are in close contact with each other.
  2. 2 . The plasma processing apparatus of claim 1 , wherein an end portion of the dielectric plate and an end portion of the upper electrode are connected to each other by pressing by an elastic member.
  3. 3 . The plasma processing apparatus of claim 1 , wherein the width of the gap increases from the end portion of each of the upper electrode and the dielectric plate toward a center portion thereof.
  4. 4 . The plasma processing apparatus of claim 1 , wherein the width of the gap decreases from the end portion of each of the upper electrode and the dielectric plate toward a center portion thereof.
  5. 5 . The plasma processing apparatus of claim 1 , wherein a lower surface of the upper electrode exposed in the gap has a wavy shape.
  6. 6 . The plasma processing apparatus of claim 1 , further comprising: a drive mechanism that moves the dielectric rod in a reference direction intersecting a lower surface of the upper electrode exposed to the gap, wherein the dielectric rod is connected to or joined to the dielectric plate, or is integrated with the dielectric plate.
  7. 7 . The plasma processing apparatus of claim 6 , wherein the drive mechanism drives the dielectric rod in the reference direction to increase/decrease the width of the gap.
  8. 8 . The plasma processing apparatus of claim 7 , wherein the drive mechanism comprises: a motor, a first pulley, an insulating shaft, a belt, and a driving part, wherein the motor is provided on the upper electrode, wherein the first pulley, the belt, and the driving part are provided in the upper electrode, wherein the insulating shaft is connected to the motor, wherein the first pulley connects the insulating shaft and the belt, wherein the driving part connects the dielectric rod and the belt and drives the dielectric rod in the reference direction by using power of the motor transmitted via the insulating shaft and the belt, wherein the driving part includes a second pulley and a shaft, wherein the second pulley connects the belt and the shaft, and wherein the shaft is connected to the dielectric rod via a floating joint.
  9. 9 . The plasma processing apparatus of claim 6 , wherein the drive mechanism moves the dielectric rod along the reference direction so as to separate the upper electrode and the dielectric plate from each other, so that the width of the gap increases.
  10. 10 . The plasma processing apparatus of claim 9 , wherein the drive mechanism comprises: a motor, a first pulley, an insulating shaft, a belt, and a driving part, wherein the motor is provided on the upper electrode, wherein the first pulley, the belt, and the driving part are provided in the upper electrode, wherein the insulating shaft is connected to the motor, wherein the first pulley connects the insulating shaft and the belt, wherein the driving part connects the dielectric rod and the belt and drives the dielectric rod in the reference direction by using power of the motor transmitted via the insulating shaft and the belt, wherein the driving part includes a second pulley and a shaft, wherein the second pulley connects the belt and the shaft, and wherein the shaft is connected to the dielectric rod.
  11. 11 . The plasma processing apparatus of claim 1 , wherein the dielectric plate is a shower plate.
  12. 12 . The plasma processing apparatus of claim 11 , wherein the upper electrode has a plurality of first gas discharge holes, wherein the dielectric plate has a plurality of second gas discharge holes, wherein the plurality of first gas discharge holes and the plurality of second gas discharge holes communicate with each other through the gap, and wherein at least some of the plurality of first gas discharge holes and at least some of the plurality of second gas discharge holes are provided so as to overlap each other.
  13. 13 . The plasma processing apparatus of claim 1 , wherein the gap communicates with a gas pipe connected to an external gas supply part.
  14. 14 . The plasma processing apparatus of claim 1 , wherein the stage comprises: a main body formed of an insulator; and a conductive layer provided in the main body, wherein the conductive layer has a shortest distance from an upper surface of the stage among one or more conductive layers provided in the stage and is formed in an annular shape.
  15. 15 . The plasma processing apparatus of claim 14 , wherein the conductive layer has an outer diameter smaller than a diameter of a substrate placed on the stage.
  16. 16 . The plasma processing apparatus of claim 14 , wherein the conductive layer is any one of an electrode for generating an electrostatic attractive force between the stage and a substrate placed on the stage, an electrode to which a high frequency is supplied, and a grounded electrode.
  17. 17 . The plasma processing apparatus of claim 14 , wherein the conductive layer is formed in a mesh shape.

Description

This is a National Phase Application filed under 35 U.S.C. 371 as a national stage of PCT/JP2019/046237, filed Nov. 26, 2019, an application claiming the benefit of Japanese Application No. JP 2018-229232, filed Dec. 6, 2018, the content of each of which is hereby incorporated by reference in its entirety. TECHNICAL FIELD Exemplary embodiments of the present disclosure relate to a plasma processing apparatus and a plasma processing method. BACKGROUND A plasma processing apparatus is used to manufacture electronic devices. Patent Document 1 discloses a technique relating to a plasma processing apparatus. The plasma processing apparatus includes a vacuum container, a process chamber, a support electrode, an antenna and a radiation port, and a magnetic field forming means. The process chamber is provided inside the vacuum container and is supplied with a gas. The support electrode is provided in the process chamber and supports an object to be processed. The antenna and the radiation port supply the high frequency of a very high frequency (VHF) band or an ultra high frequency (UHF) band to the process chamber. The magnetic field forming means forms a magnetic field in the process chamber. The plasma processing apparatus includes an electric field control space. The electric field control space is composed of a dielectric and a metal partition plate or disc-shaped metal surrounding the dielectric. The VHF band is a frequency band in the range of about 30 to 300 [MHz]. The UHF band is a frequency band in the range of about 300 [MHz] to 3 [GHz]. PRIOR ART DOCUMENTS Patent Documents Patent Document 1: Japanese laid-open publication No. 2003-243376 The present disclosure provides some embodiments of a technique capable of improving plasma uniformity in a parallel plate-type plasma processing apparatus having a plasma excitation frequency of a VHF band or an UHF band. SUMMARY According to an exemplary embodiment, there is provided a plasma processing apparatus. The plasma processing apparatus includes a process container, a stage, a dielectric plate, an upper electrode, a waveguide, and an end portion of the waveguide. The stage is provided in the process container. The dielectric plate is provided above the upper surface of the stage via a space in the process container. The upper electrode is provided above the dielectric plate. The waveguide guides a high frequency of a VHF band or an UHF band. The end portion of the waveguide is located toward the space and radiates a high frequency into the space. An gap is provided between the upper electrode and the dielectric plate. The width of the gap is non-uniform in a direction in which the dielectric plate extends. According to the present disclosure, it is possible to provide a technique capable of improving plasma uniformity in a parallel plate-type plasma processing apparatus having a plasma excitation frequency of a VHF band or an UHF band. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a view illustrating the configuration of a plasma processing apparatus according to an exemplary embodiment. FIG. 2 is a view illustrating the configuration of a plasma processing apparatus according to another exemplary embodiment. FIG. 3 is a view illustrating in detail a portion of the configuration illustrated in FIG. 2. FIG. 4 is a view illustrating in more detail a portion of the configuration illustrated in FIGS. 2 and 3. FIG. 5 is a view illustrating in more detail another configuration that can be used in place of the configuration illustrated in FIG. 3. FIG. 6 is a view illustrating the configuration of a plasma processing apparatus according to another exemplary embodiment. FIG. 7 is a view illustrating an example of the shape of the lower surface of an upper electrode illustrated in each of FIGS. 1, 2, and 6. FIG. 8 is a view illustrating an example of the shape of an gap between the upper electrode and a dielectric plate. FIG. 9 is a view illustrating another example of the shape of the gap between the upper electrode and the dielectric plate. FIG. 10 is a view illustrating a stage according to another exemplary embodiment. FIG. 11 is a view illustrating a stage according to another exemplary embodiment. DETAILED DESCRIPTION Various exemplary embodiments will now be described. According to an exemplary embodiment, there is provided a plasma processing apparatus. The plasma processing apparatus includes a process container, a stage, a dielectric plate, an upper electrode, a waveguide, and an end portion of the waveguide. The stage is provided in the process container. The dielectric plate is provided above the upper surface of the stage via a space in the process container. The upper electrode is provided above the dielectric plate. The waveguide guides a high frequency of a VHF band or an UHF band. The end portion of the waveguide is located toward the space and radiates a high frequency into the space. An gap is provided between the upper electrode and the dielectric plate. T