Plasma processing apparatus, semiconductor component, and edge ring

Abstract

The present application provides a plasma processing apparatus, a semiconductor member, and an edge ring. The plasma processing apparatus includes a semiconductor member and a power supply portion. The semiconductor member constitutes at least a part of a chamber in which plasma processing is performed or is arranged in the chamber, and is made of a semiconductor material. The power supply portion supplies electric power to the semiconductor member or sets the semiconductor member to a GND potential. Further, the plasma processing apparatus is provided with a conductive portion at least at a contact surface at which the semiconductor member and the power supply portion are in contact. According to the present application, occurrence of abnormal discharge between the semiconductor member and the power supply portion can be suppressed.

Description

TECHNICAL FIELD

[0001] The present application relates to a plasma processing apparatus, a semiconductor member, and an edge ring. BACKGROUND

[0002] Patent Document 1 discloses a technique of applying a voltage to a focus ring to perform plasma processing.

[0003] PRIOR ART DOCUMENT

[0004] PATENT DOCUMENT

[0005] Patent Document 1: Japanese Patent Application Publication No. 2018-195817 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] The present application provides a technique of suppressing occurrence of abnormal discharge between a semiconductor member and a power supply portion.

[0008] MEANS FOR SOLVING THE PROBLEM

[0009] A plasma processing apparatus of one embodiment of the present application includes a semiconductor member and a power supply portion. The semiconductor member constitutes at least a part of a chamber in which plasma processing can be performed or is arranged in the chamber, and is made of a semiconductor material. The power supply portion supplies electric power to the semiconductor member or sets the semiconductor member to a GND potential. Further, the plasma processing apparatus includes an electrically conductive portion provided at least at a contact surface at which the semiconductor member and the power supply portion are in contact.

[0010] EFFECTS OF THE INVENTION

[0011] According to the present application, occurrence of abnormal discharge between a semiconductor member and a power supply portion can be suppressed. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 FIG. 1 is a view schematically showing one example of a cross section of a plasma processing apparatus of an embodiment.

[0013] Figure 2 FIG. 2 is a view schematically showing a structure of a plasma processing apparatus of an embodiment.

[0014] Figure 3 FIG. 3 is a view showing one example of a structure of a stage of an embodiment.

[0015] Figure 4 FIG. 4 is a view schematically showing a structure of a conventional power supply portion.

[0016] Figure 5A FIG. 5 is a view schematically showing a structure of a power supply portion of the present embodiment.

[0017] Figure 5BFig. 1 is a diagram schematically showing the structure of a power supply portion of the present embodiment.

[0018] Figure 5C Fig. 1 is a diagram schematically showing the structure of a power supply portion of the present embodiment.

[0019] Figure 6 Fig. 3 is a diagram showing the temperature distribution of the focus ring caused by the change in the specific resistance of the conductive portion.

[0020] Figure 7A Fig. 1 is a diagram schematically showing the structure of a power supply portion of the present embodiment.

[0021] Figure 7B Fig. 5 is a diagram showing one example of the results of a test for measuring the leakage amount of the heat transfer gas.

[0022] Figure 8A Fig. 1 is a diagram schematically showing the structure of a power supply portion of the present embodiment.

[0023] Figure 8B Fig. 5 is a diagram showing one example of the results of a test for measuring the leakage amount of the heat transfer gas.

[0024] Figure 9A Fig. 1 is a diagram schematically showing the structure of a power supply portion of the present embodiment.

[0025] Figure 9B Fig. 5 is a diagram showing one example of the results of a test for measuring the leakage amount of the heat transfer gas.

[0026] Explanation of Reference Numerals

[0027] 10 plasma processing apparatus

[0028] 12 chamber

[0029] 13 support table

[0030] 30 shower head

[0031] 48 baffle

[0032] 51 exhaust port

[0033] 73 upper electrode

[0034] 74 GND member

[0035] 70a to 70e power supply portion

[0036] 80a to 80e conductive portion DETAILED DESCRIPTION

[0037] Embodiments of a plasma processing apparatus, a semiconductor member, and an edge ring according to the present disclosure will be described below in detail with reference to the accompanying drawings. Note that the disclosed plasma processing apparatus, semiconductor member, and edge ring are not limited by the embodiments.

[0038] In a plasma processing apparatus, there are cases where a semiconductor member formed using a semiconductor material such as useful Si, SiC, or the like is used. For example, in a plasma processing apparatus, there are cases where an edge ring such as a focus ring disposed around a substrate, an upper electrode, a GND member set to a GND potential, a chamber wall, a baffle, or the like uses a semiconductor material. In a case where power is supplied to such a semiconductor member using a semiconductor material, there is a problem that abnormal discharge occurs between a power supply portion that supplies power to the semiconductor member and the semiconductor member.

[0039] Therefore, a technology capable of suppressing the occurrence of abnormal discharge between a semiconductor member and a power supply portion is desired.

[0040] [Structure of Plasma Processing Apparatus]

[0041] One example of a plasma processing apparatus according to an embodiment will be described. In the present embodiment, a case where a plasma processing apparatus performs plasma etching as plasma processing on a substrate will be described as an example. Note that the substrate is a wafer. Figure 1 FIG. 1 is a view schematically showing one example of a cross section of a plasma processing apparatus 10 according to the present embodiment. Figure 1 The plasma processing apparatus 10 shown in the drawing is a capacitively coupled plasma processing apparatus.

[0042] The plasma processing apparatus 10 includes a chamber 12. The chamber 12 is substantially cylindrical, for example, is made of aluminum or the like, and is airtightly configured. The chamber 12 provides an inner space thereof as a processing space 12c in which plasma processing is performed. The chamber 12 is formed with a coating film having plasma resistance on an inner wall surface thereof. The coating film can be an aluminum oxide film, or a film formed of yttrium oxide. The chamber 12 is grounded. An opening 12g is formed in a side wall of the chamber 12. A wafer W is passed through the opening 12g when the wafer W is carried into the processing space 12c from the outside of the chamber 12, and when the wafer W is carried out of the processing space 12c to the outside of the chamber 12. A gate 14 is installed in the side wall of the chamber 12 in order to open and close the opening 12g.

[0043] The chamber 12 is provided with a support table 13 that supports the wafer W near the center of the inside thereof. The support table 13 includes a support portion 15 and a placement table 16. The support portion 15 is substantially cylindrical, and is provided on the bottom of the chamber 12. The support portion 15 is made of, for example, an insulating material. The support portion 15 extends upward from the bottom of the chamber 12 in the chamber 12. The placement table 16 is provided in the processing space 12c. The placement table 16 is supported by the support portion 15.

[0044] The stage 16 is configured in a manner to hold a wafer W placed thereon. The stage 16 has a lower electrode 18 and an electrostatic chuck 20. The lower electrode 18 includes a first plate 18a and a second plate 18b. The first plate 18a and the second plate 18b are configured of a metal such as aluminum, for example, and have a substantially disc shape. The second plate 18b is provided on the first plate 18a and is electrically connected to the first plate 18a.

[0045] The electrostatic chuck 20 is provided on the second plate 18b. The electrostatic chuck 20 has an insulating layer and a film-like electrode provided in the insulating layer. The electrode of the electrostatic chuck 20 is electrically connected to a direct current power supply 22 via a switch 23. A direct current voltage is applied to the electrode of the electrostatic chuck 20 from the direct current power supply 22. When the direct current voltage is applied to the electrode of the electrostatic chuck 20, the electrostatic chuck 20 generates an electrostatic attractive force to attract and hold the wafer W thereto. In addition, a heater can be built in the electrostatic chuck 20 and can be connected to a heater power supply provided outside the chamber 12.

[0046] A focus ring 24 is provided on a peripheral portion of the second plate 18b. The focus ring 24 is a substantially ring-shaped plate. The focus ring 24 is disposed so as to surround the edge of the wafer W and the electrostatic chuck 20. The focus ring 24 is provided to improve the uniformity of etching. The focus ring 24 is formed of a semiconductor material. As the semiconductor material, for example, silicon (Si) and compound semiconductors such as GaAs, SiC, GaN, and the like can be cited. The focus ring 24 is formed so as to have a larger diameter than the stage 16, and the outer periphery thereof is disposed on the support portion 15.

[0047] Further, the plasma processing apparatus 10 is configured to be capable of supplying electric power to the focus ring 24. For example, the plasma processing apparatus 10 is configured to be capable of applying a direct current voltage to the focus ring 24 in order to attract the focus ring 24 to the stage 16. A power supply portion 70a is provided on the support portion 15 at a portion below the focus ring 24. The power supply portion 70a is in contact with the focus ring 24. The power supply portion 70a is connected to a power supply 72a via a wiring 71a. The power supply 72a supplies a direct current voltage to the focus ring 24 in a pulsed manner. By thus applying a voltage to the focus ring 24, the electric field on the focus ring 24 can be changed, and the thickness of the plasma sheath can be changed. The power supply 72a supplies a direct current voltage to the focus ring 24 in a pulsed manner in a manner such that the thickness of the plasma sheath is substantially uniform above the wafer W and above the focus ring 24, under the control of a control portion 90 described later.

[0048] A flow path 18f is provided inside the second plate 18b. Temperature adjustment fluid is supplied from a refrigeration unit provided outside the chamber 12 to the flow path 18f via a pipe 26a. The temperature adjustment fluid supplied to the flow path 18f is returned to the refrigeration unit via a pipe 26b. That is, the temperature adjustment fluid is circulated between the flow path 18f and the refrigeration unit. By controlling the temperature of this temperature adjustment fluid, the temperature of the stage 16 (or electrostatic chuck 20) and the temperature of the wafer W can be adjusted. In addition, as the temperature adjustment fluid, for example, "Galden" (registered trademark) can be cited.

[0049] Gas supply lines 28a, 28b are provided in the plasma processing apparatus 10. The gas supply lines 28a, 28b are supplied with heat transfer gas, such as He gas, from a heat transfer gas supply mechanism. The gas supply line 28a communicates with a through hole provided near the center of the stage 16, and supplies heat transfer gas between the upper surface of the electrostatic chuck 20 and the back surface of the wafer W. The gas supply line 28b communicates with a through hole provided near the outer periphery of the stage 16, and supplies heat transfer gas between the upper surface near the outer periphery of the stage 16 and the back surface of the focus ring 24.

[0050] The plasma processing apparatus 10 further includes a shower head 30. The shower head 30 is provided above the stage 16. The shower head 30 is supported to the upper portion of the chamber 12 via an insulating member 32. The shower head 30 can include an electrode plate 34 and a support body 36. The lower surface of the electrode plate 34 faces the processing space 12c. A plurality of exhaust holes 34a are provided in the electrode plate 34. The electrode plate 34 can be formed of a material such as silicon or silicon oxide.

[0051] The support body 36 is a member that detachably supports the electrode plate 34, and is formed of an electrically conductive material such as aluminum. In addition, both the electrode plate 34 and the support body 36 can be formed using a semi-conductive material.

[0052] A gas diffusion chamber 36a is provided inside the support body 36. A plurality of gas flow holes 36b that communicate with the exhaust holes 34a extend downward from the gas diffusion chamber 36a. A gas introduction port 36c that introduces gas to the gas diffusion chamber 36a is formed in the support body 36. A gas supply pipe 38 is connected to the gas introduction port 36c.

[0053] A gas source group 40 is connected to the gas supply pipe 38 via a gas valve group 42 and a flow controller group 44. The gas source group 40 includes gas sources of various gases used in plasma etching. The gas valve group 42 includes a plurality of gas valves. The flow controller group 44 includes a plurality of flow controllers such as mass flow controllers or pressure-controlled flow controllers. The plurality of gas sources of the gas source group 40 are connected to the gas supply pipe 38 via corresponding gas valves of the gas valve group 42 and corresponding flow controllers of the flow controller group 44, respectively. The gas source group 40 supplies various gases for plasma etching to the gas diffusion chamber 36a of the support body 36 via the gas supply pipe 38. The gases supplied to the gas diffusion chamber 36a are dispersed in a shower-like manner into the chamber 12 from the gas diffusion chamber 36a via the exhaust hole 34a and the gas throughflow hole 36b.

[0054] A first high-frequency power supply 62 is connected to the lower electrode 18 via a matching device 63. Further, a second high-frequency power supply 64 is connected to the lower electrode 18 via a matching device 65. The first high-frequency power supply 62 is a power supply that generates high-frequency power for plasma generation. The first high-frequency power supply 62 supplies, during plasma processing, high-frequency power of a prescribed frequency in the range of 27 to 100 MHz, in one example, 40 MHz, to the lower electrode 18 of the stage 16. The second high-frequency power supply 64 is a power supply that generates high-frequency power for ion attraction (bias). The second high-frequency power supply 64 supplies, during plasma processing, high-frequency power of a prescribed frequency in the range of 400 kHz to 13.56 MHz, which is lower than that of the first high-frequency power supply 62, in one example, 3 MHz, to the lower electrode 18 of the stage 16. In this way, the stage 16 can apply two high-frequency powers of different frequencies from the first high-frequency power supply 62 and the second high-frequency power supply 64. The shower head 30 and the stage 16 function as a pair of electrodes (upper electrode and lower electrode).

[0055] A variable DC power supply 68 is connected to the support body 36 of the shower head 30 via a low-pass filter (LPF) 66. The variable DC power supply 68 is configured to be able to supply power on and off by means of an on-off switch 67. The current and voltage of the variable DC power supply 68 and the on-off of the on-off switch 67 are controlled by a control section 90 described later. When high-frequency is applied to the stage 16 from the first high-frequency power supply 62 and the second high-frequency power supply 64 to generate plasma in the processing space, the on-off switch 67 is made to be on by the control section 90 as necessary to apply a prescribed DC voltage to the support body 36.

[0056] An exhaust port 51 is provided at the bottom of the side surface of the support table 13 of the chamber 12. The exhaust port 51 is connected to an exhaust device 50 via an exhaust pipe 52. The exhaust device 50 has a pressure controller such as a pressure regulating valve and a vacuum pump such as a turbo molecular pump. The exhaust device 50 is able to reduce the pressure in the chamber 12 to a desired pressure by exhausting the inside of the chamber 12 via the exhaust port 51 and the exhaust pipe 52.

[0057] A baffle 48 is provided in chamber 12 upstream of exhaust port 51 relative to the airflow heading towards exhaust port 51. The baffle 48 is positioned between the support platform 13 and the inner surface of chamber 12, surrounding the support platform 13. The baffle 48 is, for example, a plate-shaped component, which can be formed by coating the surface of an aluminum base material with a ceramic such as Y2O3. The baffle 48 is formed by components with numerous slits, a screen component, and numerous perforations, allowing exhaust gas to pass through. The internal space of chamber 12 is divided by the baffle 48 into a processing space 12c for plasma processing of the wafer W and an exhaust space connected to an exhaust system that exhausts gas from the exhaust pipe 52 and exhaust device 50 within chamber 12.

[0058] The plasma processing apparatus 10 also includes a control unit 90. The control unit 90 is, for example, a controller including a processor, a storage unit, an input device, a display device, etc. The control unit 90 controls each part of the plasma processing apparatus 10. In the control unit 90, the operator can use the input device to input commands and perform other operations to manage the plasma processing apparatus 10. Furthermore, in the control unit 90, the operating status of the plasma processing apparatus 10 can be visually displayed using the display device. Further, the storage unit of the control unit 90 stores control programs and processing scheme data for controlling various processes performed by the plasma processing apparatus 10 using the processor. By executing the control programs through the processor of the control unit 90, each part of the plasma processing apparatus 10 is controlled according to the processing scheme data, and the plasma processing apparatus 10 performs the desired processing.

[0059] Here, as described above, the plasma processing apparatus 10 sometimes includes a semiconductor component made of a semiconductor material in at least a portion of the chamber 12 or within the chamber 12. For example, the plasma processing apparatus 10 uses a semiconductor material in the focusing ring 24 and the spray head 30, which functions as an upper electrode. Furthermore, the plasma processing apparatus 10 sometimes uses a semiconductor material in at least a portion of the chamber 12 or in the baffle 48. Additionally, the plasma processing apparatus 10 sometimes includes a GND component made of a semiconductor material within the chamber 12 for setting a GND potential. When power is supplied to such a semiconductor component made of a semiconductor material, an abnormal discharge occurs between the power supply unit supplying power to the semiconductor component and the semiconductor component.

[0060] Figure 2 This is a simplified diagram illustrating the structure of the plasma processing apparatus 10 according to an embodiment. Figure 2 The structure of the plasma processing device 10 is simplified in the figure. Figure 2A chamber 12 is shown. A stage 16 is provided in the interior of the chamber 12 near the center. The stage 16 holds a wafer W near the center, and a focus ring 24 is disposed around the wafer W at the peripheral portion. High-frequency electric power is supplied from a first high-frequency power source 62 and a second high-frequency power source 64 to the stage 16. The focus ring 24 is formed using a semiconductor material. As the semiconductor material, for example, silicon (Si) and compound semiconductors such as GaAs, SiC, GaN, and the like can be cited. Direct-current electric power is supplied to the focus ring 24 in a pulsed manner from a power source 72a.

[0061] Further, in the interior of the chamber 12, an upper electrode 73 is provided at the upper portion of the stage 16. The upper electrode 73 is, for example, a showerhead 30 as shown. The upper electrode 73 is formed using a semiconductor material. The upper electrode 73 is connected to a variable direct-current power source 68, and electric power is supplied from the variable direct-current power source 68. Figure 1

[0062] A baffle 48 is provided around the stage 16. The baffle 48 is formed using a semiconductor material. The baffle 48 is connected to a power source 72c, and electric power is supplied from the power source 72c in a pulsed or periodic manner.

[0063] Further, in the interior of the chamber 12, an upper electrode 73 is provided at the upper portion of the stage 16. The upper electrode 73 is, for example, a showerhead 30 as shown. The upper electrode 73 is formed using a semiconductor material. The upper electrode 73 is connected to a variable direct-current power source 68, and electric power is supplied from the variable direct-current power source 68. Figure 2

[0064] The chamber 12 and the supply portion that supplies electric power can also be formed of a metal having electrical conductivity such as aluminum, for example. The electrical resistivity of aluminum is on the order of 10e -6 On the other hand, the semiconductor portion has a larger electrical resistivity than the metal having electrical conductivity. For example, although Si is a semiconductor, the electrical resistivity is reduced to about several Ω-cm by doping, and the electrical resistivity differs from that of aluminum by about six orders of magnitude. Further, the electrical contact of the semiconductor and the metal having electrical conductivity becomes a non-ohmic contact such as pn junction, hetero junction having a Schottky barrier, rectifying action, and the like, and the contact portion has a high resistance and a strong electric field, and abnormal discharge such as dielectric breakdown occurs.

[0065] Therefore, in the plasma processing apparatus 10 of the embodiment, at least an electrically conductive portion having electrical conductivity is provided at a contact surface at which the semiconductor portion and the supply portion that supplies electric power to the semiconductor portion or makes the semiconductor portion have a GND potential are in contact. The electrically conductive portion is provided at least at the contact surface in contact with the supply portion. That is, the electrically conductive portion can be provided only at the contact surface in contact with the supply portion, or can be provided at the contact surface and a surface other than the contact surface around the contact surface.

[0066] ​​For example, a conductive part is formed by transforming the contact between a semiconductor component and a power supply section from a non-ohmic contact to an ohmic contact. Examples of such transformation processes include sputtering, evaporation, plating, soldering, and annealing using conductive metals. These processes can also be combined. For instance, annealing can be performed after sputtering, evaporation, plating, or soldering to further reduce contact resistance.

[0067] Examples of conductive metals used in the transformation process include Al, Ni, Co, V, Ti, Zr, Hf, W, and Au. For instance, at the contact surface between the semiconductor component and the power supply unit, any conductive metal from Al, Ni, Co, V, Ti, Zr, Hf, W, and Au can be used for sputtering, evaporation, plating, welding, or annealing. Each transformation process (sputtering, evaporation, plating, welding) and a portion of the subsequent annealing process can also be performed within chamber 12.

[0068] In the plasma processing apparatus 10, siliconization is performed through a transformation process, and at least a conductive portion is provided on the contact surface where the semiconductor component contacts the power supply unit. For example, in Figure 2 In the plasma processing apparatus 10 shown, a conductive portion 80a is provided at the contact surface between the power supply section 70a, which supplies power from the power source 72a to the focusing ring 24, and the focusing ring 24. Furthermore, in the plasma processing apparatus 10, a conductive portion 80b is provided at the contact surface between the power supply section 70b, which supplies power from the variable DC power source 68 to the upper electrode 73, and the variable DC power source 68. Furthermore, in the plasma processing apparatus 10, a conductive portion 80c is provided at the contact surface between the power supply section 70c, which supplies power from the power source 72c to the baffle 48, and the baffle 48. Furthermore, in the plasma processing apparatus 10, a conductive portion 80d is provided at the contact surface between the power supply section 70d at the end of the grounded wiring 75 and the GND component 74. Furthermore, in the plasma processing apparatus 10, a conductive portion 80e is provided at the contact surface between the power supply section 70e at the end of the grounded wiring 76 and the chamber 12. Alternatively, the plasma processing apparatus 10 may also provide components made of Si ingots with increased doping levels as conductive parts, in addition to forming conductive parts through component transformation processing. For example, conductive parts 80a to 80e may also be components made of conductive Si ingots.

[0069] Therefore, the semiconductor component, power supply (metal), and grounding material (metal) form an ohmic contact, reducing the resistance value. Even with large high-frequency currents, abnormal heat generation and electrical losses are reduced. Furthermore, the reduced resistance suppresses abnormal discharges caused by potential difference drops, thus ensuring a stable processing flow.

[0070] Next, one example of a specific structure in which the contact surface of the semiconductor component and the power supply portion is provided with at least the conductive portion will be described. Hereinafter, one example of a specific structure in which the conductive portion 80a is provided at the contact surface of the power supply portion 70a and the focus ring 24 will be described.

[0071] Figure 3 FIG. 1 is a view showing one example of the structure of the stage 16 according to the embodiment. In Figure 3 FIG. 2 is a view showing a magnified view of the vicinity of the periphery of the stage 16.

[0072] The stage 16 has the lower electrode 18 and the electrostatic chuck 20. The lower electrode 18 has the first plate 18a and the second plate 18b. The second plate 18b is provided on the first plate 18a. The flow path 18f is provided inside the second plate 18b. The electrostatic chuck 20 is provided on the second plate 18b. The electrostatic chuck 20 generates electrostatic attraction to hold the wafer W and the focus ring 24 when a direct current voltage is applied from the direct current power supply 22 to the electrode formed inside. Alternatively, the electrostatic chuck 20 can be provided with electrodes corresponding to the regions of the wafer W and the focus ring 24, respectively, to individually hold the wafer W and the focus ring 24 by applying a direct current voltage from the direct current power supply 22 to the electrodes, respectively. In this case, a plurality of direct current power supplies 22 can be provided to be individually connected to the electrodes of the electrostatic chuck 20. Further, a direct current voltage can be individually applied from the plurality of direct current power supplies 22 to the electrodes of the electrostatic chuck 20 to individually hold the wafer W and the focus ring 24.

[0073] The stage 16 is provided with the support portion 15 made of an insulating material around the periphery. The stage 16 holds the wafer W at the center, and the focus ring 24 is arranged so as to surround the periphery of the wafer W. The focus ring 24 is formed so as to have a larger diameter than the stage 16, and the outer periphery is arranged on the support portion 15. The focus ring 24 is formed with the annular portion 24a protruding downward on the lower surface on the outer side. The annular portion 24a is formed annularly along the outer periphery of the lower surface of the focus ring 24.

[0074] The support portion 15 is provided with a power supply portion 70a that supplies electric power to the focus ring 24. The power supply portion 70a has a power supply pin 70aa, a circular arc portion 70ab, and a columnar portion 70ac. The power supply pin 70aa is provided in a plurality of numbers at intervals in the circumferential direction of the focus ring 24. For example, in the support portion 15, through holes are provided at intervals of a certain angle (for example, 30°) in the circumferential direction of the focus ring 24, and the power supply pins 70aa are arranged in the through holes. In the through holes, an insulating member 70ad made of an insulating material is arranged on the side of the placement table 16 so as to be insulated from the placement table 16. The upper surface of the tip portion of the power supply pin 70aa is spaced from the focus ring 24, and the side surface of the tip portion is in contact with the inner peripheral surface of the annular portion 24a of the focus ring 24.

[0075] The support portion 15 is provided with the circular arc portion 70ab in the interior in the circumferential direction. The lower portion of each power supply pin 70aa is connected to the circular arc portion 70ab. The columnar portion 70ac is connected to the circular arc portion 70ab.

[0076] The columnar portion 70ac is connected to the power supply 72a via the above-mentioned wiring 71a, and electric power is supplied from the power supply 72a. The electric power supplied from the power supply 72a is supplied to the focus ring 24 from the contact surface of the side surface of the tip portion of each power supply pin 70aa via the columnar portion 70ac, the circular arc portion 70ab, and the power supply pin 70aa. The contact surface of the tip portion of the power supply pin 70aa that is in contact with the focus ring 24 is provided with a conductive portion 80a that is conductive. For example, the conductive portion 80a is provided on the entire circumference of the inner peripheral surface of the annular portion 24a of the focus ring 24 in the circumferential direction.

[0077] Thus, the focus ring 24 and the power supply portion 70a are in ohmic contact, and the electric resistance value is reduced, so that even if a large high-frequency current flows, abnormal heating and electric loss at the contact surface portion are reduced. Further, by reducing the electric resistance, abnormal discharge due to a reduction in potential difference is suppressed, so that stable processing can be performed.

[0078] Next, a specific example of the effect of providing the conductive portion at the contact surface of the semiconductor member and the power supply portion will be described. First, the structure of a conventional power supply portion that is not provided with a conductive portion will be described. Figure 4 is a diagram that schematically shows the structure of a conventional power supply portion. In Figure 4 , a diagram that schematically shows the structure of a power supply portion 70a that supplies electric power to the focus ring 24. In Figure 4In the case where the conductive portion 80a is not provided at the contact surface of the focus ring 24 with the power supply portion 70a, the focus ring 24 is in direct contact with the power supply portion 70a. In this case, the electrical contact point of the focus ring 24 with the power supply portion 70a becomes a non-ohmic contact, and the contact point portion has a high resistance and a strong electric field, resulting in abnormal discharge such as dielectric breakdown. In addition, the current is concentrated at the contact surface portion of the focus ring 24 with the power supply portion 70a, and the contact surface portion of the focus ring 24 is partially heated. In the case where the focus ring 24 is partially heated as such, the focus ring 24 is deformed by heat.

[0079] Therefore, in the plasma processing apparatus 10 of the embodiment, the conductive portion 80a is provided at least at the contact surface of the focus ring 24 with the power supply portion 70a. Figures 5A-5C FIG. 6 is a diagram schematically showing the structure of the power supply portion of the embodiment. In Figures 5A-5C FIG. 7 is a diagram schematically showing the structure of the power supply portion 70a that supplies electric power to the focus ring 24. In Figure 5A In the case where the conductive portion 80a is provided at the entire surface of the lower surface of the focus ring 24 including the contact surface with the power supply portion 70a, the focus ring 24 is in contact with the power supply portion 70a via the conductive portion 80a. In this case, the electrical contact point of the focus ring 24 with the power supply portion 70a becomes an ohmic contact, and the contact point portion has a low resistance and a weak electric field, resulting in no abnormal discharge such as dielectric breakdown. In addition, the current is not concentrated at the contact surface portion of the focus ring 24 with the power supply portion 70a, and the contact surface portion of the focus ring 24 is not partially heated. In the case where the focus ring 24 is not partially heated as such, the focus ring 24 is not deformed by heat. Figure 5B In the case where the conductive portion 80a is provided at the entire surface of the inner peripheral surface of the annular portion 24a of the focus ring 24 including the contact surface with the power supply portion 70a, the focus ring 24 is in contact with the power supply portion 70a via the conductive portion 80a. In this case, the electrical contact point of the focus ring 24 with the power supply portion 70a becomes an ohmic contact, and the contact point portion has a low resistance and a weak electric field, resulting in no abnormal discharge such as dielectric breakdown. In addition, the current is not concentrated at the contact surface portion of the focus ring 24 with the power supply portion 70a, and the contact surface portion of the focus ring 24 is not partially heated. In the case where the focus ring 24 is not partially heated as such, the focus ring 24 is not deformed by heat. Figure 5C In the case where the conductive portion 80a is provided at the contact surface of the annular portion 24a of the focus ring 24 with the power supply portion 70a, the focus ring 24 is in contact with the power supply portion 70a via the conductive portion 80a. In this case, the electrical contact point of the focus ring 24 with the power supply portion 70a becomes an ohmic contact, and the contact point portion has a low resistance and a weak electric field, resulting in no abnormal discharge such as dielectric breakdown. In addition, the current is not concentrated at the contact surface portion of the focus ring 24 with the power supply portion 70a, and the contact surface portion of the focus ring 24 is not partially heated. In the case where the focus ring 24 is not partially heated as such, the focus ring 24 is not deformed by heat.

[0080] In the case where the conductive portion 80a is provided at the contact surface of the annular portion 24a of the focus ring 24 with the power supply portion 70a, the focus ring 24 is in contact with the power supply portion 70a via the conductive portion 80a. In this case, the electrical contact point of the focus ring 24 with the power supply portion 70a becomes an ohmic contact, and the contact point portion has a low resistance and a weak electric field, resulting in no abnormal discharge such as dielectric breakdown. In addition, the current is not concentrated at the contact surface portion of the focus ring 24 with the power supply portion 70a, and the contact surface portion of the focus ring 24 is not partially heated. In the case where the focus ring 24 is not partially heated as such, the focus ring 24 is not deformed by heat.

[0081] Figure 6 FIG. 8 is a diagram showing the temperature distribution of the focus ring 24 based on the change in the resistivity of the conductive portion 80a. In Figure 6 The position PI of the power supply pin 70aa of the power supply portion 70a is shown. In addition, in Figure 6 , the temperature distribution of the surface of the focus ring 24 is shown in patterns in the case where the resistivity of the conductive portion 80a is 20 Ω cm, 2 Ω cm, and 0.02 Ω cm. The focus ring 24, the darker the pattern of the region, the higher the temperature. At the electrical contact point of the focus ring 24 with the power supply portion 70a, for example, in the case where the current flowing in the power supply portion 70a is I and the resistivity of the conductive portion 80a is R, only the heat P shown in (1) below is generated.

[0082] P = R I 2 (1)

[0083] In the case where the electric resistivity of the conductive portion 80a is 20 Ω-cm, 2 Ω-cm, the current of the focus ring 24 is not sufficiently dispersed, the current density in the vicinity of the position PI of the power feeding pin 70aa of the focus ring 24 in contact with the power feeding portion 70a becomes high and local heating occurs. The focus ring 24 is deformed due to the temperature distribution caused by the local heating. The plasma processing apparatus 10 cannot stably hold the focus ring 24 when the focus ring 24 is deformed. The leakage of the heat transfer gas (He gas) supplied to the back surface of the focus ring 24 increases when the plasma processing apparatus 10 cannot hold the focus ring 24.

[0084] On the other hand, in the case where the electric resistivity of the conductive portion 80a is 0.02 Ω-cm, the current of the focus ring 24 is sufficiently dispersed, the temperature distribution is substantially uniform, and no deformation occurs. As a result, in the plasma processing apparatus 10, the focus ring 24 can be stably held.

[0085] Here, the change in the holding characteristics of the focus ring 24 will be described. Figure 7A is a view schematically showing the structure of a conventional power feeding portion. In Figure 7A , the structure of the power feeding portion 70a that supplies electric power to the focus ring 24 is schematically shown. In Figure 7A , the conductive portion 80a is not provided at the contact surface of the focus ring 24 with the power feeding portion 70a, and the focus ring 24 is in direct contact with the power feeding portion 70a. In this case, the electric resistivity of the electric contact point of the focus ring 24 with the power feeding portion 70a becomes 1 to 2 Ω-cm. Figure 7B is a view showing one example of the results of an experiment for measuring the leakage amount of the heat transfer gas. Figure 7B shows the time change in the leakage amount of the heat transfer gas (He gas) supplied to the back surface of the focus ring 24 in the case where the structure of Figure 7A is adopted. In addition, Figure 7B the pulse-shaped change in the leakage amount shown at the times tl to t3 is a temporary change caused by the start and end of the supply of the heat transfer gas. In Figure 7B , it can be judged that the leakage amount increases more as time passes. The reason why the leakage amount increases like this is considered to be the result of the local heating of the focus ring 24 and the deformation of the focus ring 24 caused by the local heating.

[0086] Figure 8A is a view schematically showing the structure of the power feeding portion of the present embodiment. In Figure 8A , the conductive portion 80a is provided at the entire surface of the inner peripheral surface of the annular portion 24a of the focus ring 24 including the contact surface with the power feeding portion 70a. Figure 8B is a view showing one example of the results of an experiment for measuring the leakage amount of the heat transfer gas. Figure 8B shows the time change in the leakage amount of the heat transfer gas (He gas) supplied to the back surface of the focus ring 24 in the case where the structure of Figure 8AThe time variation of the leakage amount of heat transfer gas (He gas) supplied to the back side of the focusing ring 24 under the structural condition. Additionally, Figure 8B The pulse-like leakage changes shown at times t1 to t3 are temporary changes caused by the start and end of the heat transfer gas supply. Figure 8B Even after time has passed, the leakage does not increase. Therefore, the focusing ring 24 remains stably adsorbed even after time has passed.

[0087] Figure 9A This is a diagram that schematically illustrates the structure of the power supply unit in this embodiment. Figure 9A In this process, a focusing ring 24 is formed using a conductive metal with a resistivity of 0.02 Ω·cm, and the entire focusing ring 24 is used as a conductive part 80a. Figure 9B This is a graph representing an example of the results of a test measuring the leakage of heat transfer gas. Figure 9B Indicates taking Figure 9A The time variation of the leakage amount of heat transfer gas (He gas) supplied to the back side of the focusing ring 24 under the structural condition. Additionally, Figure 9B The pulse-like leakage changes shown at times t1 to t3 are temporary changes caused by the start and end of the heat transfer gas supply. Figure 9B Even after time has passed, the leakage does not increase. Therefore, the focusing ring 24 remains stably adsorbed even after time has passed.

[0088] As described above, the plasma processing apparatus 10 of this embodiment includes semiconductor components (e.g., focusing ring 24, upper electrode 73 (spray head 30), baffle 48, GND component 74, chamber 12) and power supply units (e.g., power supply units 70a-70e). The semiconductor components constitute at least a portion of the chamber 12 in which plasma processing can be performed, or are disposed within the chamber 12 and are made of semiconductor material. The power supply units supply power to the semiconductor components or make the semiconductor components GND potential. Furthermore, the plasma processing apparatus 10 provides conductive portions (e.g., conductive portions 80a-80e) at least on the contact surfaces where the semiconductor components and the power supply units contact. As a result, the plasma processing apparatus 10 can suppress the occurrence of abnormal discharge between the semiconductor components and the power supply units.

[0089] Furthermore, in the plasma processing apparatus 10 of this embodiment, the semiconductor component is any one of the following components arranged on the support stage 16 of the substrate within the chamber 12, surrounding the substrate: an edge ring (e.g., a focusing ring 24), an upper electrode 73, a GND component 74 set to GND potential, the wall of the chamber 12, and a baffle 48. Therefore, the plasma processing apparatus 10 can suppress abnormal discharges between the edge ring, the upper electrode 73, the GND component 74 set to GND potential, the wall of the chamber 12, the baffle 48, and the power supply units 70a to 70e.

[0090] Further, the plasma processing apparatus 10 of the present embodiment forms the conductive portion by a prescribed conversion process that changes the contact surface with the power supply portion from a non-ohmic contact to an ohmic contact. Thus, the plasma processing apparatus 10 can suppress occurrence of abnormal discharge between the semiconductor portion and the power supply portion.

[0091] Further, the conversion process is any of sputtering, vapor deposition, plating, welding, and annealing using a conductive metal. Further, the conductive metal is any of Al, Ni, Co, V, Ti, Zr, Hf, W, and Au. Thus, the plasma processing apparatus 10 can suppress occurrence of abnormal discharge between the semiconductor portion and the power supply portion.

[0092] Further, in the plasma processing apparatus 10 of the present embodiment, the semiconductor portion is an edge ring (e.g., a focus ring 24) disposed on the stage 16 that supports a substrate within the chamber 12 in a manner that surrounds the periphery of the substrate. The power supply portion 70a is provided in the stage 16 in a manner that is spaced apart in the circumferential direction of the edge ring, and contacts the edge ring. The conductive portion 80a is provided in the entire circumferential direction at the position of the contact surface of the surface of the stage 16 side of the edge ring that contacts the power supply portion 70a. Thus, the plasma processing apparatus 10 can suppress local heating of the edge ring due to current spreading to the conductive portion 80a, and can suppress occurrence of deformation of the edge ring.

[0093] Further, the conductive portion 80a of the plasma processing apparatus 10 is provided on the entire surface of the surface of the stage 16 side of the edge ring. Thus, the plasma processing apparatus 10 can make the temperature distribution of the edge ring substantially uniform by spreading current to the entire surface of the surface of the stage 16 side of the edge ring, and can suppress occurrence of deformation of the edge ring.

[0094] The embodiments have been described above, and the embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. Indeed, the above-described embodiments can be modified in various ways. Additionally, the above-described embodiments can be omitted, replaced, or changed in various ways without departing from the scope and spirit of the claims.

[0095] For example, in the above-described embodiments, examples in which the plasma processing apparatus 10 is a capacitively coupled plasma processing apparatus have been described. However, the present technology is not limited thereto. The present technology can be employed in any plasma processing apparatus. For example, the plasma processing apparatus 10 can be any type of plasma processing apparatus, such as an inductively coupled plasma processing apparatus, a plasma processing apparatus that excites a gas using a surface wave such as a microwave, and the like.

[0096] Further, the above-described embodiment illustrates an example in the case where the lower electrode 18 is connected to the first high-frequency power source 62 and the second high-frequency power source 64, but the structure of the plasma source is not limited thereto. For example, the first high-frequency power source 62 for plasma generation can also be connected to the shower head 30. Further, the second high-frequency power source 64 for ion attraction (bias) can also not be connected to the lower electrode 18.

[0097] Further, the above-described plasma processing apparatus 10 is a plasma processing apparatus that performs etching as plasma processing, and can be employed in a plasma processing apparatus that performs arbitrary plasma processing. For example, the plasma processing apparatus 10 can be a single-wafer deposition apparatus that performs chemical vapor deposition (CVD), atomic layer deposition (ALD), physical vapor deposition (PVD), or the like, or can be a plasma processing apparatus that performs plasma annealing, plasma implantation, or the like.

[0098] Further, in the above-described embodiment, an example is described in the case where the substrate is a semiconductor wafer, but is not limited thereto. The substrate can also be another substrate such as a glass substrate.

Claims

1. A plasma processing device, characterized in that, include: The chamber contains a plasma processing space; A stage, which is disposed within the plasma processing space, has an electrostatic chuck. An edge ring, formed of a semiconductor material, is disposed on the mounting stage in such a way as to surround a substrate placed on the mounting stage. The edge ring has a main body portion and an annular portion protruding downward from the lower surface of the outer side of the main body portion. The power supply unit is disposed within the mounting platform and has a plurality of power supply pins arranged circumferentially on the edge ring, and an arc portion connected to the lower part of each of the plurality of power supply pins and extending along the circumferential direction. At least one conductive layer is formed on the inner circumferential surface of the annular portion and contacts the plurality of power supply pins, the at least one conductive layer having a resistivity of less than 0.02 Ω·cm; and The power supply is configured to apply a pulsed DC voltage to the edge ring via the power supply unit and the at least one conductive layer, thereby causing a change in the thickness of the plasma sheath above the edge ring. The sides of the front ends of the plurality of power supply pins are connected to the inner circumferential surface of the annular portion of the edge ring via the at least one conductive layer.

2. The plasma processing apparatus as described in claim 1, characterized in that: The conductive layer is in ohmic contact with the edge ring.

3. The plasma processing apparatus as described in claim 2, characterized in that: The conductive layer is formed of a conductive metal.

4. The plasma processing apparatus as described in claim 3, characterized in that: The conductive metal is any one of Al, Ni, Co, V, Ti, Zr, Hf, W, and Au.

5. The plasma processing apparatus as described in claim 4, characterized in that: The edge ring is formed from any of Si, GaAs, SiC, and GaN.

6. The plasma processing apparatus as described in claim 1, characterized in that: It also includes an insulating support portion, which is configured to surround the edge ring and is configured to support the annular portion of the edge ring.

7. The plasma processing apparatus as described in claim 1, characterized in that: A space is formed between the edge ring and the plurality of power supply pins.

8. The plasma processing apparatus as described in claim 1, characterized in that: The power supply pins are arranged at certain intervals in the circumferential direction.

9. The plasma processing apparatus as described in claim 1, characterized in that: It also includes a heat transfer gas supply mechanism configured to supply heat transfer gas between the mounting platform and the edge ring.

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