Plasma processing equipment

Abstract

To provide a technique of suppressing dissociation of gas in a plurality of gas holes of a shower head.SOLUTION: A plasma processing apparatus disclosed herein includes a chamber, a substrate support, an upper electrode, and at least one power supply. The chamber provides a processing space therein. The substrate support is provided in the chamber. The upper electrode configures a shower head that introduces a gas into the processing space from above the processing space. The upper electrode includes a first electrode and a second electrode. The first electrode provides a plurality of first gas holes opened toward the processing space. The second electrode is provided directly or indirectly on the first electrode and provides a plurality of second gas holes communicating with the plurality of first gas holes. The at least one power supply is configured to set a potential of the second electrode to a potential on the positive side with respect to a potential of the first electrode.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] An exemplary embodiment of the present disclosure relates to a plasma processing apparatus. [Background technology]

[0002] A plasma processing apparatus is used for plasma processing of a substrate. One type of plasma processing apparatus is equipped with a shower head. The shower head is provided above a substrate support part provided in a chamber. The shower head provides a plurality of gas holes. In Patent Document 1 listed below, gas grooves communicating with the plurality of gas holes are provided on the underside of the shower head in order to suppress abnormal discharge in the plurality of gas holes. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-117711 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides techniques for suppressing dissociation of gas within multiple gas holes in a showerhead. [Means for solving the problem]

[0005] In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a substrate support, an upper electrode, and at least one power supply. The chamber defines a processing space therein. The substrate support is provided within the chamber. The upper electrode forms a showerhead that introduces gas into the processing space from above. The upper electrode includes a first electrode and a second electrode. The first electrode defines a plurality of first gas holes that open toward the processing space. The second electrode is provided directly or indirectly on the first electrode and defines a plurality of second gas holes that respectively communicate with the plurality of first gas holes. The at least one power supply is configured to set the potential of the second electrode to a positive potential relative to the potential of the first electrode. [Effects of the Invention]

[0006] According to one exemplary embodiment, dissociation of gases within a plurality of gas holes in a showerhead can be suppressed. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a diagram illustrating a schematic diagram of a plasma processing apparatus according to an exemplary embodiment; [Figure 2] 1 is a partially enlarged cross-sectional view of an upper electrode of a plasma processing apparatus according to an exemplary embodiment; [Figure 3] FIG. 3(a) is a diagram showing the behavior of secondary electrons in a plasma processing apparatus according to one exemplary embodiment, and FIG. 3(b) is a diagram showing the behavior of secondary electrons when the potential of the first electrode and the potential of the second electrode are the same. [Figure 4] FIG. 2 illustrates at least one power supply employed in a plasma processing apparatus in another exemplary embodiment. [Figure 5] FIG. 10 illustrates at least one power supply employed in a plasma processing apparatus in yet another exemplary embodiment. [Figure 6] 6(a) and 6(b) are enlarged partial cross-sectional views of an upper electrode employed in a plasma processing apparatus according to yet another exemplary embodiment. [Figure 7] 10 is a partial enlarged cross-sectional view of an upper electrode employed in a plasma processing apparatus in yet another exemplary embodiment. [Figure 8] 10 is a cross-sectional view of an upper electrode employed in a plasma processing apparatus in yet another exemplary embodiment. [Figure 9] 10 is a cross-sectional view of an upper electrode employed in a plasma processing apparatus in yet another exemplary embodiment. [Figure 10] 10 is a cross-sectional view of an upper electrode employed in a plasma processing apparatus in yet another exemplary embodiment. [Figure 11] 1 is an example timing chart. [Figure 12] 1 is an example timing chart. [Figure 13] 1 is an example timing chart. [Figure 14] 1 is an example timing chart. [Figure 15] 15(a) and 15(b) are diagrams showing an example of a configuration related to power supply control. [Figure 16] 16(a) and 16(b) are diagrams showing an example of a configuration related to power supply control. DETAILED DESCRIPTION OF THE INVENTION

[0008] Various exemplary embodiments will be described in detail below with reference to the drawings, in which the same or equivalent parts are designated by the same reference numerals.

[0009] 1 is a schematic diagram of a plasma processing apparatus according to an exemplary embodiment. In one embodiment, a plasma processing system is provided as shown in FIG. The plasma processing system includes a plasma processing apparatus 1. The plasma processing apparatus 1 may further include a controller 2.

[0010] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform various processes. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to perform various processes. In one embodiment, part or all of the control unit 2 may be included in the plasma processing apparatus 1. The control unit 2 may include, for example, a computer 2a. The computer 2a may include, for example, a processing unit (CPU: Central Processing Unit) 2a1, a storage unit 2a2, and a communication interface 2a3. The processing unit 2a1 may be configured to perform various control operations based on programs stored in the storage unit 2a2. The storage unit 2a2 may include a random access memory (RAM), a read-only memory (ROM), a hard disk drive (HDD), a solid state drive (SSD), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication line such as a local area network (LAN).

[0011] The plasma processing apparatus 1 is a capacitively coupled plasma processing apparatus. The plasma processing apparatus 1 includes a chamber 10, a substrate support 12, and an upper electrode 14. The chamber 10 provides a processing space 10s therein. The chamber 10 has a substantially cylindrical shape. The sidewall of the chamber 10 is electrically grounded.

[0012] The plasma processing apparatus 1 may further include an exhaust system 40. The exhaust system 40 may be connected to a gas exhaust port 10e provided at the bottom of the chamber 10, for example. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure in the processing space 10s is regulated by the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0013] A substrate support 12 is provided in the chamber 10. The substrate support 12 is configured to support a substrate W placed thereon. The substrate support 12 may be configured to further support an edge ring ER placed thereon. The substrate W is disposed on the substrate support 12 within a region surrounded by the edge ring ER.

[0014] In one embodiment, the substrate support 12 may include a base 16 and an electrostatic chuck 18. The base 16 includes a conductive member. The conductive member of the base 16 functions as a lower electrode. The electrostatic chuck 18 is disposed on the base 16. The substrate W is placed on the electrostatic chuck 18. The electrostatic chuck 18 is configured to hold the substrate W by electrostatic attraction.

[0015] The substrate support 12 may include a temperature adjustment module configured to adjust at least one of the electrostatic chuck 18, the edge ring ER, and the substrate W to a target temperature. The temperature adjustment module may include a heater, a heat transfer medium, a flow path, or a combination thereof. A heat transfer medium such as brine or gas flows through the flow path. The substrate support 12 may further include a heat transfer gas supply unit configured to supply a heat transfer gas to the gap between the back surface of the substrate W and the electrostatic chuck 18.

[0016] The plasma processing apparatus 1 may further include a radio frequency power supply 31 and a bias power supply 32. The radio frequency power supply 31 is configured to supply source radio frequency power RF to generate plasma from gas in the chamber 10. The source radio frequency power RF has a frequency within a range of 13 MHz to 150 MHz. The radio frequency power supply 31 is connected to the radio frequency electrode via a matching device 31m. The matching device 31m includes a matching circuit for matching the impedance of the load of the radio frequency power supply 31 to the output impedance of the radio frequency power supply 31. The radio frequency electrode may be an electrode of the substrate support 12, for example, a conductive member of the base 16. The radio frequency electrode may be another electrode of the substrate support 12. Alternatively, the radio frequency electrode may be the upper electrode 14.

[0017] The bias power supply 32 is electrically connected to a bias electrode of the substrate support 12 (e.g., a conductive member of the base 16). The bias power supply 32 is configured to supply electrical bias energy BE to the bias electrode of the substrate support 12 to attract ions from the plasma to the substrate W placed on the substrate support 12. Note that the bias power supply 32 may be electrically connected to an electrode of the substrate support 12 that is separate from the conductive member of the base 16.

[0018] The electrical bias energy BE has a waveform period CY (see FIGS. 11-14) and is supplied periodically. The waveform period CY has a duration that is the reciprocal of the bias frequency. The bias frequency can be in the range of 100 kHz to 13.56 MHz.

[0019] The electrical bias energy BE may be bias RF power (see the substrate potential in FIG. 14) or may include voltage pulses (see the bias electrode potential in FIGS. 11 to 13). The bias RF power has a bias frequency. The waveform of the bias RF power is a sine wave having the bias frequency. When the electrical bias energy BE is bias RF power, the bias power supply 32 is connected to the bias electrode of the substrate support 12 via a matching device 32m. The matching device 32m includes a matching circuit for matching the impedance of the load of the bias power supply 32 to the output impedance of the bias power supply 32.

[0020] The voltage pulses are periodically generated at a time interval that is the reciprocal of the bias frequency. The voltage pulses may have negative polarity. The voltage pulses may be generated from a DC voltage. The voltage pulses may have any waveform, such as a rectangular pulse wave, a triangular pulse wave, or an impulse wave.

[0021] Hereinafter, reference will be made to FIG. 2 together with FIG. 1. FIG. 2 is a partially enlarged cross-sectional view of an upper electrode of a plasma processing apparatus according to one exemplary embodiment. The upper electrode 14 constitutes a showerhead that introduces gas into the processing space 10s from above. The upper electrode 14 closes the upper end opening of the sidewall of the chamber 10 and defines the processing space 10s. The upper electrode 14 is electrically insulated from the sidewall of the chamber 10.

[0022] The upper electrode 14 includes a first electrode 21 and a second electrode 22. The first electrode 21 has a substantially disk shape. The first electrode 21 is made of, for example, silicon, silicon carbide, or quartz. The lower surface of the first electrode 21 contacts the processing space 10s. The first electrode 21 has a plurality of first gas holes 21h. The plurality of first gas holes 21h penetrate the first electrode 21 in its plate thickness direction and open toward the processing space 10s.

[0023] The second electrode 22 is provided directly on the first electrode 21. Alternatively, the second electrode 22 may be provided indirectly on the first electrode 21. The second electrode 22 has a substantially disk shape. The second electrode 22 is made of a metal such as aluminum or silicon carbide. The surface of the second electrode 22 may be made of a film 22a. The film 22a is a corrosion-resistant film, such as an alumite film formed by anodizing. The second electrode 22 provides a plurality of second gas holes 22h. The second gas holes 22h extend vertically and are respectively connected to the plurality of first gas holes 21h.

[0024] The second electrode 22 may further include a gas diffusion chamber 22d and a gas introduction port 22p. The gas diffusion chamber 22d is provided in the second electrode 22. A plurality of second gas holes 22h extend downward from the gas diffusion chamber 22d. The gas introduction port 22p is connected to the gas diffusion chamber 22d. A gas supply unit 24 is connected to the gas introduction port 22p.

[0025] The gas supply unit 24 may include one or more gas sources 24s and one or more flow rate controllers 24c. The gas supply unit 24 is configured to supply one or more gases from the corresponding gas sources 24s to the gas inlet port 22p via the corresponding flow rate controllers 24c. The one or more gases supplied to the gas inlet port 22p are introduced into the chamber 10 via the gas diffusion chamber 22d, the plurality of second gas holes 22h, and the plurality of first gas holes 21h.

[0026] In one embodiment, the end 22t of each of the multiple second gas holes 22h on the first electrode 21 side may be tapered. That is, the end 22t of each of the multiple second gas holes 22h on the first electrode 21 side may have a diameter that increases as the vertical distance from the corresponding first gas hole 21h decreases. In one embodiment, the diameter of the opening (lower end opening) of the end 22t is larger than the diameter of the corresponding first gas hole 21h. According to this embodiment, even if a misalignment occurs between each second gas hole 22h and the corresponding first gas hole 21h due to a difference in the thermal expansion coefficients of the first electrode 21 and the second electrode 22, each second gas hole 22h and the corresponding first gas hole 21h can remain in communication with each other.

[0027] In one embodiment, the second electrode 22 may have a temperature adjustment mechanism. The temperature adjustment mechanism may include a flow path 22f formed in the second electrode 22. A supply device for a heat medium (e.g., a refrigerant) is connected to the flow path 22f. The supply device is provided outside the chamber 10. The heat medium supplied from the supply device to the flow path 22f flows through the flow path 22f and is returned to the supply device. Note that the temperature adjustment mechanism of the second electrode 22 may include a heater in addition to the flow path 22f.

[0028] The plasma processing apparatus 1 further includes at least one power supply. The at least one power supply is configured to set the potential of the second electrode 22 to a positive potential relative to the potential of the first electrode 21. That is, the at least one power supply sets the potential of the second electrode 22 to a potential higher on the positive side than the potential of the first electrode 21. The potential of the first electrode 21 may be a negative potential, 0 V (ground potential), or floating. For example, the potential of the first electrode 21 may be a positive potential, and the potential of the second electrode 22 may be higher on the positive side than the potential of the first electrode 21. Alternatively, the potential of the first electrode 21 may be 0 V, and the potential of the second electrode 22 may be a positive potential. Alternatively, the potential of the first electrode 21 may be a negative potential, and the potential of the second electrode 22 may be 0 V. Alternatively, the potential of the first electrode 21 may be a negative potential, and the potential of the second electrode 22 may be a negative potential that is more positive than the potential of the first electrode 21 .

[0029] 1 and 2, the plasma processing apparatus 1 includes a single DC power supply 51 as at least one power supply, and further includes a resistive divider circuit 52. The DC power supply 51 may be a variable DC power supply. The positive electrode of the DC power supply 51 is connected to ground. The negative electrode of the DC power supply 51 is connected to one end of the resistive divider circuit 52. Two nodes 52c and 52d having different potentials in the resistive divider circuit 52 are electrically connected to the first electrode 21 and the second electrode 22, respectively.

[0030] In one embodiment, the resistive divider circuit 52 includes resistors 52a and 52b. One end of the resistor 52a is connected to the negative electrode of the DC power supply 51. The node 52c is provided on an electrical path connecting one end of the resistor 52a and the negative electrode of the DC power supply 51 to each other, and is electrically connected to the first electrode 21. The node 52c may be connected to the first electrode 21 via a filter 53f and a switch 53s. The filter 53f is a low-pass filter that blocks or attenuates high-frequency power.

[0031] One end of resistor 52b is electrically connected to the other end of resistor 52a, and the other end of resistor 52b is connected to ground. Node 52d is provided on the electrical path connecting one end of resistor 52b and the other end of resistor 52a, and is electrically connected to second electrode 22. Node 52d may be connected to second electrode 22 via filter 54f and switch 54s. Filter 54f is a low-pass filter that blocks or attenuates high-frequency power.

[0032] As shown in Fig. 1, the resistor 52a may be a fixed resistor. Alternatively, as shown in Fig. 2, the resistor 52a may be a variable resistor. When the resistor 52a is a variable resistor, it becomes possible to adjust the potential difference between the first electrode 21 and the second electrode 22. Furthermore, the resistor 52b may be a fixed resistor or a variable resistor.

[0033] In the plasma processing apparatus 1 including such a resistive divider circuit 52, the potential of the first electrode 21 is negative. The potential of the second electrode 22 is negative and positive relative to the potential of the first electrode 21.

[0034] Reference will now be made to FIGS. 3(a) and 3(b). FIG. 3(a) illustrates the behavior of secondary electrons in a plasma processing apparatus according to an exemplary embodiment, and FIG. 3(b) illustrates the behavior of secondary electrons when the potentials of the first electrode and the second electrode are the same. In FIGS. 3(a) and 3(b), circles surrounding "+" indicate positive ions, and circles surrounding "-" indicate secondary electrons. In the plasma processing apparatus 1, the showerhead provides multiple gas holes. Each of the multiple gas holes includes one of the multiple first gas holes 21h and a second gas hole 22h communicating with the first gas hole 21h. When the potentials of the first electrode 21 and the second electrode 22 are the same, positive ions from the plasma enter the multiple gas holes and collide with the second electrode 22, generating secondary electrons, which can cause a discharge. Meanwhile, in the plasma processing apparatus 1, the potential of the second electrode 22 is set to a positive potential relative to the potential of the first electrode 21. Therefore, in the plasma processing apparatus 1, even if positive ions from the plasma in the processing space 10s enter the plurality of gas holes and collide with the second electrode 22, causing secondary electrons to be emitted from the second electrode 22, the secondary electrons are immediately attracted to the second electrode 22. Therefore, the secondary electrons are prevented from colliding with the gas in the plurality of gas holes and causing dissociation of the gas in the plurality of gas holes.

[0035] In one embodiment, the difference between the potential of the second electrode 22 and the potential of the first electrode 21 may be 5 V or more. Such a potential difference more effectively suppresses gas dissociation within the gas holes.

[0036] Reference will now be made to FIGS. 4 and 5. FIG. 4 is a diagram illustrating at least one power supply employed in a plasma processing apparatus in another exemplary embodiment. FIG. 5 is a diagram illustrating at least one power supply employed in a plasma processing apparatus in yet another exemplary embodiment. As shown in FIGS. 4 and 5, the plasma processing apparatus 1 may include, as at least one power supply, a first power supply and a second power supply, i.e., a DC power supply 511 and a DC power supply 512. Each of the DC power supply 511 and the DC power supply 512 may be a variable DC power supply.

[0037] In the embodiment shown in FIG. 4, the positive electrode of the DC power supply 511 is connected to ground. The negative electrode of the DC power supply 511 is connected to the first electrode 21 via a filter 53f and a switch 53s. The positive electrode of the DC power supply 512 is connected to ground. The negative electrode of the DC power supply 512 is connected to the second electrode 22 via a filter 54f and a switch 54s. In the embodiment shown in FIG. 4 as well, the potential of the first electrode 21 is a negative potential. The potential of the second electrode 22 is also a negative potential. The potential of the second electrode 22 is set to a positive potential relative to the potential of the first electrode 21.

[0038] In the embodiment shown in FIG. 5, the positive electrode of the DC power supply 511 is connected to ground. The negative electrode of the DC power supply 511 is connected to the first electrode 21 via a filter 53f and a switch 53s. The negative electrode of the DC power supply 512 is connected to the negative electrode of the DC power supply 511. The positive electrode of the DC power supply 512 is connected to the second electrode 22 via a filter 54f and a switch 54s. In the embodiment shown in FIG. 5 as well, the potential of the first electrode 21 is a negative potential. The potential of the second electrode 22 can also be a negative potential. The potential of the second electrode 22 is set to a positive potential relative to the potential of the first electrode 21.

[0039] The embodiment shown in Fig. 5 is similar to the embodiment shown in Fig. 4 in that it uses DC power supplies 511 and 512. However, in the embodiment shown in Fig. 4, there are cases where high-voltage power supplies must be used as DC power supplies 511 and 512. On the other hand, in the embodiment shown in Fig. 5, even if a relatively low-voltage power supply is used as DC power supply 512, the potential difference between first electrode 21 and second electrode 22 can be appropriately set.

[0040] 6(a) and 6(b) are referenced below. Each of FIGS. 6(a) and 6(b) is a partially enlarged cross-sectional view of an upper electrode employed in a plasma processing apparatus in yet another exemplary embodiment. As shown in FIGS. 6(a) and 6(b), the upper electrode 14 may further include a dielectric layer 23. The dielectric layer 23 is formed of silicon, silicon carbide, or aluminum oxide.

[0041] 6(a), the dielectric layer 23 is provided between the first electrode 21 and the second electrode 22. The dielectric layer 23 may be formed by thermal spraying on the upper surface of the first electrode 21 or the lower surface of the second electrode 22. Alternatively, the dielectric layer 23 may be a plate made of a dielectric material, and may be sandwiched between the upper surface of the first electrode 21 and the lower surface of the second electrode 22.

[0042] 6(b), the dielectric layer 23 may be formed on the lower surface of the first electrode 21. The dielectric layer 23 may be formed on the lower surface of the first electrode 21 by thermal spraying. Alternatively, the dielectric layer 23 may be a plate made of a dielectric material, and may be fixed to the lower surface of the first electrode 21. The dielectric layer 23 may also be formed on the upper surface of the second electrode 22.

[0043] Reference is now made to FIG. 7, which is a partially enlarged cross-sectional view of an upper electrode employed in a plasma processing apparatus in yet another exemplary embodiment. As shown in FIG. 7, the upper electrode 14 may further include a conductive layer 22g. The conductive layer 22g is formed on a surface region that defines each end 22t of the plurality of second gas holes 22h. The conductive layer 22g is made of a conductive material. The conductive layer 22g is made of, for example, silicon, silicon carbide, aluminum, or titanium.

[0044] At least one power supply may apply a voltage to the conductive layer 22g to set the potential of the second electrode 22 described above. In the example shown in Fig. 7, the node 52d is connected to the conductive layer 22g via a filter 54f and a switch 54s. When the DC power supplies 511 and 512 are used as shown in Fig. 4, the negative electrode of the DC power supply 512 is connected to the conductive layer 22g via the filter 54f and the switch 54s. When the DC power supplies 511 and 512 are used as shown in Fig. 5, the positive electrode of the DC power supply 512 is connected to the conductive layer 22g via the filter 54f and the switch 54s.

[0045] In the embodiment shown in Fig. 7, the resistor 52a may be a fixed resistor or a variable resistor, and in the embodiment shown in Fig. 7, the resistor 52b may be a fixed resistor or a variable resistor.

[0046] 8 to 10 are referenced below. Each of Figs. 8 to 10 is a cross-sectional view of an upper electrode employed in a plasma processing apparatus in yet another exemplary embodiment. In the upper electrode 14 employed in the plasma processing apparatus 1, the first electrode 21 or both the first electrode 21 and the second electrode 22 may be separated into a plurality of portions in the radial and / or circumferential directions.

[0047] In the embodiment shown in FIG. 8, the first electrode 21 includes a portion 21c and a portion 21e. The portions 21c and 21e are separated from each other. The portion 21c constitutes a central region of the first electrode 21 in the radial direction. The portion 21c is a circular region in a plan view. The portion 21e is a region radially outward of the portion 21c and constitutes a peripheral region of the first electrode 21. The portion 21e is an annular region in a plan view. A space may be provided between the portion 21c and the portion 21e, and an insulating material may be provided between the portion 21c and the portion 21e.

[0048] 8, each of the portion 21c and the portion 21e is electrically connected to a DC power supply 511 via a filter 53f and a switch 53s. The second electrode 22 is electrically connected to a DC power supply 512 via a filter 54f and a switch 54s.

[0049] In the embodiment shown in FIG. 9, similar to the embodiment shown in FIG. 8, the first electrode 21 includes a portion 21c and a portion 21e. In the embodiment shown in FIG. 9, the second electrode 22 includes a portion 22c and a portion 22e. The portions 22c and 22e are separated from each other. The portion 22c forms a central region of the second electrode 22 in the radial direction. The portion 22c is a circular region in a plan view. The portion 22c is provided on the portion 21c. The portion 22e is a region radially outward of the portion 22c and forms a peripheral region of the second electrode 22. The portion 22e is an annular region in a plan view. The portion 22e is provided on the portion 21e. A space may be provided between the portion 22c and the portion 22e, and an insulating material may be provided between the portion 22c and the portion 22e.

[0050] 9, a DC power supply 511 is electrically connected to each of the portions 21c and 21e via a filter 53f and a switch 53s. A DC power supply 512 is electrically connected to each of the portions 22c and 22e via a filter 54f and a switch 54s.

[0051] In the embodiment shown in FIG. 10 , the first electrode 21 includes a portion 21m in addition to the portion 21c and the portion 21e. The portions 21c, 21m, and 21e are separated from one another. The portion 21m is a region between the portion 21c and the portion 21e. The portion 21m is an annular region in a plan view. A space may be provided between the portion 21c and the portion 21m, and an insulating material may be provided between the portion 21c and the portion 21m. A space may be provided between the portion 21m and the portion 21e, and an insulating material may be provided between the portion 21m and the portion 21e.

[0052] 10, each of the portions 21c, 21m, and 21e is electrically connected to a DC power supply 511 via a filter 53f and a switch 53s. The second electrode 22 is electrically connected to a DC power supply 512 via a filter 54f and a switch 54s.

[0053] 11 to 14 are referenced below. Each of Figures 11 to 14 shows an example of a timing chart. Each of Figures 11 to 14 shows a timing chart of the potential of the bias electrode of the substrate support 12, the potential of the plasma generated in the chamber 10, and the potential of each of the first and second electrodes of the upper electrode.

[0054] As shown in Figures 11 to 14, the waveform period CY includes periods P1 and P2. Period P1 is a negative phase period within the waveform period CY. The potential of the substrate W or the potential of the bias electrode in period P1 is lower than the average potential of the substrate W or the average potential of the bias electrode in the waveform period CY. In period P1, the potential of the substrate W or the potential of the bias electrode may be a negative potential. Period P2 is a period within the waveform period CY other than period P1, and is a positive phase period within the waveform period CY. In period P2, the potential of the substrate W or the potential of the bias electrode may be 0 V or higher.

[0055] 11 to 14, at least one power supply of the plasma processing apparatus 1, i.e., DC power supply 51 or DC power supplies 511 and 512, may set the potential of the first electrode 21 to a constant value such as potential V21A. Also, at least one power supply of the plasma processing apparatus 1 may set the potential of the second electrode 22 to a constant value such as potential V22A.

[0056] 11 to 14, at least one power supply of the plasma processing apparatus 1, i.e., DC power supply 51 or DC power supplies 511 and 512, may change the potential of the first electrode 21 in synchronization with the electrical bias energy BE, such as potential V21B or V21C. Also, at least one power supply of the plasma processing apparatus 1 may change the potential of the second electrode 22 in synchronization with the electrical bias energy BE, such as potential V22B or V22C.

[0057] Specifically, at least one power supply of the plasma processing apparatus 1 may set the potential of the first electrode 21 during period P2 to a potential, such as potential V21B or V21C, that is higher on the positive side than the negative potential of the first electrode 21 during period P1. Furthermore, at least one power supply of the plasma processing apparatus 1 may set the potential of the second electrode 22 during period P2 to a potential, such as potential V22B or V22C, that is higher on the positive side than the negative potential of the second electrode 22 during period P1. In this case, it is possible to reduce the potential difference between the plasma and the upper electrode 14 during period P2. As a result, it is possible to reduce the velocity of ions moving from the plasma toward the upper electrode 14 and suppress the generation of secondary electrons.

[0058] Furthermore, at least one power supply of the plasma processing apparatus 1 may set the absolute value of the negative potential of the first electrode 21 in the period P1 to a value greater than the absolute value of the potential of the first electrode 21 in the period P2, as in potential V21B or V21C. At least one power supply of the plasma processing apparatus 1 may set the absolute value of the negative potential of the second electrode 22 in the period P1 to a value greater than the absolute value of the potential of the second electrode 22 in the period P2, as in potential V22B or V22C. In this case, even if secondary electrons are emitted from the substrate W due to collision of ions with the substrate W in the period P1, the speed of the secondary electrons moving toward the upper electrode 14 is reduced.

[0059] 11 to 14, the potential of each of the first electrode 21 and the second electrode 22 in the waveform period CY may take two potentials (the potential in period P1 and the potential in period P2), i.e., two values. In another example, the number of periods in the waveform period CY may be any number other than two. Furthermore, the potentials of the first electrode 21 and the second electrode 22 in the waveform period CY may change smoothly.

[0060] 15(a) and 15(b) are diagrams illustrating an example configuration related to power supply control. As shown in FIG. 15(a), the plasma processing apparatus 1 may further include a power supply controller 60 for changing the potentials of the first electrode 21 and the second electrode 22 in synchronization with the electrical bias energy BE. The power supply controller 60 provides a synchronization signal to the bias power supply 32 and the DC power supply 51. The power supply controller 60 also provides a phase signal to the DC power supply 51. The bias power supply 32 generates the electrical bias energy BE in synchronization with the provided synchronization signal. The DC power supply 51 changes the potentials of the first electrode 21 and the second electrode 22 in synchronization with the provided synchronization signal and in accordance with the phase signal. The waveform of the output voltage of the DC power supply 51 within the waveform period CY may be preset or may be set based on recipe data. Alternatively, as shown in FIG. 15(b), the bias power supply 32 may generate a synchronization signal and a phase signal and provide them to the DC power supply 51.

[0061] 16(a) and 16(b) are diagrams illustrating an example configuration related to power supply control. As shown in FIG. 16(a), the plasma processing apparatus 1 may further include a power supply controller 61 for changing the potentials of the first electrode 21 and the second electrode 22 in synchronization with the electrical bias energy BE. The power supply controller 61 provides synchronization signals to the bias power supply 32, the DC power supply 511, and the DC power supply 512. The power supply controller 61 also provides phase signals to the DC power supplies 511 and 512. The bias power supply 32 generates electrical bias energy BE in synchronization with the provided synchronization signal. Each of the DC power supplies 511 and 512 synchronizes with the provided synchronization signal and changes the potentials of the first electrode 21 and the second electrode 22 in response to the phase signal. The waveforms of the output voltages of the DC power supplies 511 and 512 within the waveform period CY may be preset or may be set based on recipe data. Alternatively, as shown in FIG. 16(b), the bias power supply 32 may generate a synchronization signal and a phase signal and provide them to the DC power supplies 511 and 512.

[0062] Although various exemplary embodiments have been described above, the present invention is not limited to the above-described exemplary embodiments, and various additions, omissions, substitutions, and modifications may be made. Furthermore, elements in different embodiments may be combined to form other embodiments.

[0063] For example, at least one of the plurality of second gas holes 22h or each of the plurality of second gas holes 22h may be in communication with two or more of the plurality of first gas holes 21h. Furthermore, each of the plurality of first gas holes 21h may be bent.

[0064] Various exemplary embodiments included in the present disclosure are now described in [E1] to [E16] below.

[0065] [E1] a chamber providing a processing space therein; a substrate support disposed within the chamber; an upper electrode constituting a shower head that introduces gas into the processing space from above the processing space; a first electrode providing a plurality of first gas holes opening toward the processing space; a second electrode provided directly or indirectly on the first electrode and providing a plurality of second gas holes respectively communicating with the plurality of first gas holes; the upper electrode comprising: at least one power supply configured to set the potential of the second electrode to a positive potential relative to the potential of the first electrode; A plasma processing apparatus comprising:

[0066] In the embodiment of [E1], the showerhead provides a plurality of gas holes. Each of the plurality of gas holes includes one of the plurality of first gas holes and a second gas hole communicating therewith. In the embodiment of [E1], even if positive ions from the plasma in the processing space enter the plurality of gas holes and collide with the second electrode, causing secondary electrons to be emitted from the second electrode, the secondary electrons are immediately attracted to the second electrode. Therefore, collisions of the secondary electrons with the gas in the plurality of gas holes and dissociation of the gas in the plurality of gas holes are suppressed.

[0067] [E2] The plasma processing apparatus according to [E1], wherein the potential of the second electrode is higher than the potential of the first electrode by +5 V or more.

[0068] [E3] The plasma processing apparatus according to [E1] or [E2], wherein the at least one power supply is configured to set the potential of the first electrode to a negative potential, 0 V, or floating.

[0069] [E4] the at least one power source comprises a single power source; further comprising a resistor divider circuit connected to the single power supply; The plasma processing apparatus according to any one of [E1] to [E3], wherein two nodes having different potentials in the resistive divider circuit are electrically connected to the first electrode and the second electrode, respectively.

[0070] [E5] The plasma processing apparatus according to any one of [E1] to [E3], comprising, as the at least one power supply, a first power supply electrically connected to the first electrode, and a second power supply separate from the first power supply and electrically connected to the second electrode.

[0071] [E6] The plasma processing apparatus according to any one of [E1] to [E5], further comprising a dielectric layer provided between the first electrode and the second electrode.

[0072] [E7] the second electrode has a conductive layer on a surface region that defines an end of each of the second gas holes on the first electrode side; the at least one power source is configured to apply a voltage to the conductive layer; The plasma processing apparatus according to any one of [E1] to [E6].

[0073] [E8] the first electrode includes a plurality of portions separated from one another; the at least one power source is configured to apply a voltage to the plurality of portions; The plasma processing apparatus according to any one of [E1] to [E6].

[0074] [E9] The plasma processing apparatus according to [E8], wherein the plurality of portions of the first electrode are separated from each other in a radial direction.

[0075] [E10] The plasma processing apparatus according to any one of [E1] to [E9], wherein the second electrode has a temperature control mechanism.

[0076] [E11] The plasma processing apparatus according to [E10], wherein the temperature adjustment mechanism is a flow path formed in the second electrode, and includes the flow path through which a heat medium flows.

[0077] [E12] an end portion of each of the second gas holes on the side of the first electrode is tapered; a diameter of the opening at the end of each of the plurality of second gas holes is larger than a diameter of each of the plurality of first gas holes; The plasma processing apparatus according to any one of [E1] to [E11].

[0078] [E13] the first electrode is formed from silicon, silicon carbide, or quartz; The second electrode is formed from a metal or silicon carbide. The plasma processing apparatus according to any one of [E1] to [E12].

[0079] [E14] configured to periodically supply electrical bias energy having a waveform period to the substrate support; the waveform period includes a negative phase period in which the potential of the substrate is lower than an average potential of the substrate within the waveform period, and a positive phase period which is a period within the waveform period other than the negative phase period; the at least one power supply is configured to set a potential of the first electrode during the positive phase period to a potential that is more positive than a negative potential of the first electrode during the negative phase period. The plasma processing apparatus according to any one of [E1] to [E13].

[0080] [E15] configured to periodically supply electrical bias energy having a waveform period to the substrate support; the waveform period includes a negative phase period in which the potential of the substrate is lower than an average potential of the substrate within the waveform period, and a positive phase period which is a period within the waveform period other than the negative phase period; the at least one power supply is configured to set an absolute value of the negative potential of the first electrode during the negative phase period to a value greater than an absolute value of the potential of the first electrode during the positive phase period; The plasma processing apparatus according to any one of [E1] to [E13].

[0081] [E16] The plasma processing apparatus according to [E14] or [E15], wherein the electrical bias energy is bias high frequency power or a voltage pulse generated periodically at the time interval of the waveform period.

[0082] From the foregoing, it will be understood that various embodiments of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope and spirit of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, with the true scope and spirit being indicated by the appended claims. [Explanation of symbols]

[0083] 1...plasma processing apparatus, 10...chamber, 12...substrate support portion, 14...upper electrode, 21...first electrode, 21h...first gas hole, 22...second electrode, 22h...second gas hole, 51...DC power supply.

Claims

1. a chamber providing a processing space therein; a substrate support disposed within the chamber; an upper electrode constituting a shower head that introduces gas into the processing space from above the processing space; a first electrode providing a plurality of first gas holes opening toward the processing space; a second electrode provided directly or indirectly on the first electrode and providing a plurality of second gas holes respectively communicating with the plurality of first gas holes; the upper electrode comprising: at least one power supply configured to set the potential of the second electrode to a positive potential relative to the potential of the first electrode; Equipped with the at least one power source comprises a single power source; further comprising a resistor divider circuit connected to the single power supply; two nodes having different potentials in the resistive divider circuit are electrically connected to the first electrode and the second electrode, respectively; Plasma processing equipment.

2. A chamber providing a processing space therein; a substrate support disposed within the chamber; an upper electrode constituting a shower head that introduces gas into the processing space from above the processing space; a first electrode providing a plurality of first gas holes opening toward the processing space; a second electrode provided directly or indirectly on the first electrode and providing a plurality of second gas holes respectively communicating with the plurality of first gas holes; the upper electrode comprising: at least one power supply configured to set the potential of the second electrode to a positive potential relative to the potential of the first electrode; Equipped with the second electrode has a conductive layer on a surface region that defines an end of each of the second gas holes on the first electrode side; the at least one power source is configured to apply a voltage to the conductive layer; Plasma processing equipment.

3. A chamber providing a processing space therein; a substrate support disposed within the chamber; an upper electrode constituting a shower head that introduces gas into the processing space from above the processing space; a first electrode providing a plurality of first gas holes opening toward the processing space; a second electrode provided directly or indirectly on the first electrode and providing a plurality of second gas holes respectively communicating with the plurality of first gas holes; the upper electrode comprising: at least one power supply configured to set the potential of the second electrode to a positive potential relative to the potential of the first electrode; Equipped with an end portion of each of the plurality of second gas holes on the side of the first electrode is tapered; a diameter of the opening at the end of each of the plurality of second gas holes is larger than a diameter of each of the plurality of first gas holes; Plasma processing equipment.

4. A method for manufacturing a substrate support, the method comprising: periodically supplying electrical bias energy having a waveform period to the substrate support; the waveform period includes a negative phase period in which the potential of the substrate is lower than an average potential of the substrate within the waveform period, and a positive phase period which is a period within the waveform period other than the negative phase period; the at least one power supply is configured to set an absolute value of the negative potential of the first electrode during the negative phase period to a value greater than an absolute value of the potential of the first electrode during the positive phase period; The plasma processing apparatus according to any one of claims 1 to 3.

5. A plasma processing apparatus as described in claim 4, wherein the electrical bias energy is bias high-frequency power or a voltage pulse generated periodically at the time interval of the waveform period.

6. A chamber providing a processing space therein; a substrate support disposed within the chamber; an upper electrode constituting a shower head that introduces gas into the processing space from above the processing space; a first electrode providing a plurality of first gas holes opening toward the processing space; a second electrode provided directly or indirectly on the first electrode and providing a plurality of second gas holes respectively communicating with the plurality of first gas holes; the upper electrode comprising: at least one power supply configured to set the potential of the second electrode to a positive potential relative to the potential of the first electrode; Equipped with configured to periodically supply electrical bias energy having a waveform period to the substrate support; the waveform period includes a negative phase period in which the potential of the substrate is lower than an average potential of the substrate within the waveform period, and a positive phase period which is a period within the waveform period other than the negative phase period; the at least one power supply is configured to set a potential of the first electrode during the positive phase period to a potential that is higher on the positive side than a negative potential of the first electrode during the negative phase period; Plasma processing equipment.

7. 7. The plasma processing apparatus of claim 6, wherein the electrical bias energy is a bias high frequency power or a voltage pulse generated periodically at a time interval of the waveform period.

8. the first electrode includes a plurality of portions separated from one another; the at least one power source is configured to apply a voltage to the plurality of portions; 7. The plasma processing apparatus according to claim 1, 2, 3, or 6.

9. The plasma processing apparatus of claim 8 , wherein the portions of the first electrode are radially separated from one another.

10. The plasma processing apparatus according to any one of claims 2 to 3 and 6, comprising, as the at least one power supply, a first power supply electrically connected to the first electrode, and a second power supply separate from the first power supply and electrically connected to the second electrode.

11. 7. The plasma processing apparatus according to claim 1, wherein the potential of the second electrode is higher than the potential of the first electrode by +5 V or more.

12. 7. The plasma processing apparatus according to claim 1, wherein the at least one power supply is configured to set the potential of the first electrode to a negative potential, 0 V, or to a floating potential.

13. 7. The plasma processing apparatus according to claim 1, further comprising a dielectric layer provided between the first electrode and the second electrode.

14. 7. The plasma processing apparatus according to claim 1, wherein the second electrode has a temperature control mechanism.

15. The plasma processing apparatus according to claim 14 , wherein the temperature adjustment mechanism is a flow path formed in the second electrode, and includes the flow path through which a heat medium flows.

16. the first electrode is formed from silicon, silicon carbide, or quartz; The second electrode is made of metal or silicon carbide.

7. The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus is a plasma processing apparatus.

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