Substrate processing equipment

Abstract

To provide a substrate processing apparatus that suppresses electrical discharge while controlling an incident angle of an ion in an outer periphery of a substrate.SOLUTION: In a substrate processing apparatus comprising a plasma processing chamber storing a substrate and a ring assembly provided around the substrate, the ring assembly comprises: a dielectric body; and a potential forming part that is arranged on the dielectric body and is formed of a conductive material. A bottom surface of the potential forming part is arranged at a position being higher than a top surface of the substrate, and the substrate processing apparatus comprises a power supply that supplies a DC signal or an RF signal to the potential forming part.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a substrate processing apparatus.

Background Art

[0002] Patent Document 1 discloses a plasma processing apparatus characterized in that current path correction means is provided to correct a current path portion near the outer periphery of a wafer in a high-frequency current path by a high-frequency bias so as to face the wafer-facing surface of a counter electrode.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] On one side, the present disclosure provides a substrate processing apparatus that suppresses discharge while controlling the incident angle of ions at the outer peripheral portion of a substrate.

Means for Solving the Problems

[0005] In order to solve the above problems, according to one aspect, there is provided a substrate processing apparatus including a plasma processing chamber that houses a substrate and a ring assembly provided around the substrate, the ring assembly having a dielectric and a potential forming portion disposed on the dielectric and formed of a conductive material, a lower surface of the potential forming portion being disposed at a position higher than an upper surface of the substrate, and including a power supply that supplies a DC signal or an RF signal to the potential forming portion.

Effects of the Invention

[0006] According to one aspect, it is possible to provide a substrate processing apparatus that suppresses fluctuations in the incident angle of ions at the outer peripheral portion of a substrate. [Brief explanation of the drawing]

[0007] [Figure 1] An example of a diagram illustrating an example configuration of a capacitively coupled plasma processing apparatus according to the first embodiment. [Figure 2] An example of a cross-sectional view of a substrate support portion in a plasma processing apparatus according to the first embodiment. [Figure 3] An example of simulation results showing ion orbitals near the outer edge of the substrate. [Figure 4] An example of simulation results showing ion orbitals near the outer edge of the substrate. [Figure 5] An example of simulation results showing ion orbitals near the outer edge of the substrate. [Figure 6] An example of a graph showing simulation results. [Figure 7] An example of a diagram illustrating the configuration of a capacitively coupled plasma processing apparatus according to the second embodiment. [Figure 8] An example of a cross-sectional view of a substrate support portion in a plasma processing apparatus according to the second embodiment. [Figure 9] An example of simulation results showing ion orbitals near the outer edge of the substrate. [Figure 10] An example of a cross-sectional view of a substrate support portion in a plasma processing apparatus according to the third embodiment. [Figure 11] An example of a cross-sectional view of a substrate support portion in a plasma processing apparatus according to the fourth embodiment. [Figure 12] An example of a cross-sectional view of a substrate support portion in a plasma processing apparatus according to the fifth embodiment. [Figure 13] An example graph showing the relationship between the height of the third ring and the discharge. [Modes for carrying out the invention]

[0008] Various exemplary embodiments will be described in detail below with reference to the drawings. In each drawing, the same or corresponding parts will be denoted by the same reference numerals.

[0009] The following describes an example of the configuration of a plasma processing system. Figure 1 is an example of a diagram illustrating an example of the configuration of a capacitively coupled plasma processing apparatus according to the first embodiment.

[0010] The plasma processing system includes a capacitively coupled plasma processing apparatus 1 and a control unit 2. The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply 30, and an exhaust system 40. The plasma processing apparatus 1 also includes a substrate support unit 11 and a gas introduction unit. The gas introduction unit is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas introduction unit includes a shower head 13. The substrate support unit 11 is located inside the plasma processing chamber 10. The shower head 13 is located above the substrate support unit 11. In one embodiment, the shower head 13 constitutes at least a portion of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the shower head 13, the side walls 10a of the plasma processing chamber 10, and the substrate support unit 11. The plasma processing chamber 10 has at least one gas supply port for supplying at least one processing gas to the plasma processing space 10s and at least one gas outlet for discharging gas from the plasma processing space. The plasma processing chamber 10 is grounded. The shower head 13 and the substrate support part 11 are electrically insulated from the housing of the plasma processing chamber 10.

[0011] The substrate support portion 11 includes a main body portion 111 and a ring assembly 112. The main body portion 111 has a central region 111a for supporting the substrate W and an annular region 111b for supporting the ring assembly 112. A wafer is an example of the substrate W. The annular region 111b of the main body portion 111 surrounds the central region 111a of the main body portion 111 in a plan view. The substrate W is placed on the central region 111a of the main body portion 111, and the ring assembly 112 is placed on the annular region 111b of the main body portion 111 so as to surround the substrate W on the central region 111a of the main body portion 111. Therefore, the central region 111a is also called the substrate support surface for supporting the substrate W, and the annular region 111b is also called the ring support surface for supporting the ring assembly 112.

[0012] In one embodiment, the main body 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive member. The conductive member of the base 1110 can function as a lower electrode. The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic electrode 1111b disposed within the ceramic member 1111a. The ceramic member 1111a has a central region (111a). In one embodiment, the ceramic member 1111a also has an annular region 111b. Note that other members surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member, may have the annular region 111b. In this case, the ring assembly 112 may be disposed on the annular electrostatic chuck or the annular insulating member, or may be disposed on both the electrostatic chuck 1111 and the annular insulating member. Also, at least one RF / DC electrode coupled to an RF (Radio Frequency) power supply 31 and / or a DC (Direct Current) power supply 32 described later may be disposed within the ceramic member 1111a. In this case, the at least one RF / DC electrode functions as a lower electrode. When a bias RF signal and / or a DC signal described later is supplied to the at least one RF / DC electrode, the RF / DC electrode is also referred to as a bias electrode. Note that the conductive member of the base 1110 and the at least one RF / DC electrode may function as a plurality of lower electrodes. Also, the electrostatic electrode 1111b may function as a lower electrode. Therefore, the substrate support portion 11 includes at least one lower electrode.

[0013] The ring assembly 112 includes one or more annular members. In one embodiment, the one or more annular members include one or more edge rings and at least one cover ring. The edge ring is formed of a conductive material or an insulating material, and the cover ring is formed of an insulating material.

[0014] Here, the ring assembly 112 has a first ring 112a, a second ring 112b, and a third ring 112c. Note that the ring assembly 112 will be described later with reference to FIG. 2.

[0015] In addition, in the annular region 111b of the main body 111, a gas supply passage 113 for supplying backside gas for heat transfer is provided between the back surface of the ring assembly 112 (first ring 112a) and the annular region 111b. The backside gas is supplied from a gas supply source 114 to the gas supply passage 113. For example, He gas can be used as the backside gas.

[0016] Further, the substrate support 11 may include a temperature control module configured to adjust at least one of the electrostatic chuck 1111, the ring assembly 112, and the substrate to a target temperature. The temperature control module may include a heater, a heat transfer medium, a flow path 1110a, or a combination thereof. A heat transfer fluid such as brine or gas flows through the flow path 1110a. In one embodiment, the flow path 1110a is formed in the base 1110, and one or more heaters are disposed in the ceramic member 1111a of the electrostatic chuck 1111. Further, the substrate support 11 may include a heat transfer gas supply unit configured to supply heat transfer gas to the gap between the back surface of the substrate W and the central region 111a.

[0017] The shower head 13 is configured to introduce at least one process gas from the gas supply unit 二十 into the plasma processing space 10s. The shower head 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and a plurality of gas introduction ports 13c. The process gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space 10s from the plurality of gas introduction ports 13c. Further, the shower head 13 includes at least one upper electrode. The gas introduction unit may include, in addition to the shower head 13, one or more side gas injection parts (SGI: Side Gas Injector) attached to one or more openings formed in the side wall 10a.

[0018] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one processing gas to the shower head 13 from a corresponding gas source 21 via a corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Furthermore, the gas supply unit 20 may include one or more flow modulation devices that modulate or pulse the flow rate of at least one processing gas.

[0019] The power supply 30 includes an RF power supply 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply at least one RF signal (RF power) to at least one lower electrode and / or at least one upper electrode. This causes plasma to be formed from at least one processing gas supplied to the plasma processing space 10s. Thus, the RF power supply 31 can function as at least part of a plasma generation unit configured to generate plasma from one or more processing gases in the plasma processing chamber 10. In addition, by supplying a bias RF signal to at least one lower electrode, a bias potential is generated on the substrate W, and ionic components in the formed plasma can be drawn into the substrate W.

[0020] In one embodiment, the RF power supply 31 includes a first RF generation unit 31a and a second RF generation unit 31b. The first RF generation unit 31a is coupled to at least one lower electrode and / or at least one upper electrode via at least one impedance matching circuit and is configured to generate a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 10 MHz to 150 MHz. In one embodiment, the first RF generation unit 31a may be configured to generate a plurality of source RF signals having different frequencies. One or more generated source RF signals are supplied to at least one lower electrode and / or at least one upper electrode.

[0021] The second RF generation unit 31b is coupled to at least one lower electrode via at least one impedance matching circuit and is configured to generate a bias RF signal (bias RF power). The frequency of the bias RF signal may be the same as or different from the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency lower than the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 100 kHz to 60 MHz. In one embodiment, the second RF generation unit 31b may be configured to generate a plurality of bias RF signals having different frequencies. One or more generated bias RF signals are supplied to at least one lower electrode. In various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0022] The power supply 30 may also include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generation unit 32a, a second DC generation unit 32b, and a third DC generation unit 32c. In one embodiment, the first DC generation unit 32a is connected to at least one lower electrode and configured to generate a first DC signal. The generated first bias DC signal is applied to at least one lower electrode. In one embodiment, the second DC generation unit 32b is connected to at least one upper electrode and configured to generate a second DC signal. The generated second DC signal is applied to at least one upper electrode. In one embodiment, the third DC generation unit 32c is connected to the third ring 112c of the ring assembly 112 and configured to generate a third DC signal. The generated third bias DC signal is applied to the third ring 112c of the ring assembly 112.

[0023] In various embodiments, at least one of the first and second DC signals may be pulsed. In this case, a sequence of voltage pulses is applied to at least one lower electrode and / or at least one upper electrode. The voltage pulses may have a rectangular, trapezoidal, triangular, or combination thereof pulse waveform. In one embodiment, a waveform generation unit for generating a sequence of voltage pulses from a DC signal is connected between the first DC generation unit 32a and at least one lower electrode. Thus, the first DC generation unit 32a and the waveform generation unit constitute a voltage pulse generation unit. When the second DC generation unit 32b and the waveform generation unit constitute a voltage pulse generation unit, the voltage pulse generation unit is connected to at least one upper electrode. The voltage pulses may have positive or negative polarity. The sequence of voltage pulses may also include one or more positive voltage pulses and one or more negative voltage pulses within one cycle. The first and second DC generation units 32a and 32b may be provided in addition to the RF power supply 31, and the first DC generation unit 32a may be provided in place of the second RF generation unit 31b.

[0024] The exhaust system 40 may be connected to, for example, a gas outlet 10e located at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure regulating valve regulates the pressure in the plasma processing space 10s. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0025] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform various processes described herein. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to perform the various processes described herein. 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 a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The control unit 2 is implemented, for example, by a computer 2a. The processing unit 2a1 may be configured to perform various control operations by reading a program from the storage unit 2a2 and executing the read program. This program may be stored in the storage unit 2a2 in advance, or it may be obtained via a medium when needed. The obtained program is stored in the storage unit 2a2 and read from the storage unit 2a2 and executed by the processing unit 2a1. The medium may be various storage media readable by the computer 2a, or it may be a communication line connected to the communication interface 2a3. The processing unit 2a1 may be a CPU (Central Processing Unit). The memory unit 2a2 may include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing device 1 via a communication line such as a LAN (Local Area Network).

[0026] Next, the substrate support portion 11 of the plasma processing apparatus 1 according to the first embodiment will be further described with reference to Figures 2 to 6. Figure 2 is an example of a cross-sectional view of the substrate support portion 11 in the plasma processing apparatus 1 according to the first embodiment. In Figure 2, an example of equipotential lines when plasma 200 is generated is shown as a dashed line.

[0027] The ring assembly 112 includes a first ring 112a, a second ring 112b, and a third ring 112c.

[0028] The first ring 112a is an annular member formed of a conductive material and is arranged to surround the substrate W. Si, SiC, etc., can be used as the conductive material for the first ring 112a. The first ring 112a is positioned in the annular region 111b. The first DC generation unit 32a (see Figure 1) applies a first DC signal to the lower electrode of the base 1110 (see Figure 1), generating a potential in the substrate W and the first ring 112a placed on the electrostatic chuck 1111. The first ring 112a is also referred to as the edge ring.

[0029] The second ring 112b is an annular member formed of a dielectric material and is provided on top of the first ring 112a. SiO2 or the like can be used as the dielectric material for the second ring 112b.

[0030] The third ring 112c is an annular member formed of a conductive material and is provided on the second ring 112b. Si, SiC, etc., can be used as the conductive material for the third ring 112c. Furthermore, the third DC generation unit 32c applies a third DC signal to the third ring 112c, generating a potential in the third ring 112c. The third DC generation unit 32c is a variable power supply and is configured to allow for variable strength of the DC signal (voltage) applied to the third ring 112c. In the ring assembly 112 according to the first embodiment, the third ring 112c is an example of a potential forming unit.

[0031] Furthermore, the lower surface of the third ring 112c is positioned higher than the upper surface of the substrate W placed on the electrostatic chuck 1111.

[0032] Furthermore, the inner diameter of the second ring 112b is larger than the inner diameter of the first ring 112a. Also, the inner diameter of the third ring 112c is larger than the inner diameter of the first ring 112a and is equal to the inner diameter of the second ring 112b. As a result, the upper surface of the ring assembly 112 has a stepped portion.

[0033] Figures 3 to 5 show examples of simulation results illustrating ion orbitals near the outer periphery of the substrate W. The horizontal axis represents the radial position R [mm] from the center of the substrate W, and the vertical axis represents the height direction. The edge of the substrate W is at a radius of 150 mm. In Figures 3 to 5, the potential of the substrate W is set to -800 V, and the potential of the first ring 112a is also set to -800 V. The DC signal applied from the third DC generation unit 32c to the third ring 112c was also varied. An example of equipotential lines when Ar gas is supplied from the gas supply unit 20 via the showerhead 13 and an Ar gas plasma is generated is shown as a dashed line.

[0034] Figure 3 shows the orbital 310 of the Ar ion when the potential of the third ring 112c is -100V. In this case, on the inner circumference side of the substrate W (left side of Figure 3), equipotential lines are arranged almost uniformly in the height direction. On the other hand, on the outer circumference side of the substrate W (right side of 150mm in Figure 3), the potential difference between the first ring 112a and the third ring 112c is larger than in the cases of Figures 4 and 5 described later, and an equipotential line shape is formed in which more equipotential lines pass between the first ring 112a and the third ring 112c than in the cases of Figures 4 and 5 described later. As a result, as shown in the orbital 310 of the Ar ion in Figure 3, the incident angle of the Ar ion near the outer circumference of the substrate W can be made inward. In addition, the number of equipotential lines passing over the third ring 112c is less than in the cases of Figures 4 and 5 described later. Therefore, the thickness of the sheath above the third ring 112c is thinner than in the cases of Figures 4 and 5 described later.

[0035] Figure 4 shows the orbital 320 of the Ar ion when the potential of the third ring 112c is -300V. In this case, on the inner circumference side of the substrate W (left side of Figure 4), equipotential lines are arranged almost uniformly in the height direction. On the other hand, on the outer circumference side of the substrate W (to the right of 150mm in Figure 4), the potential difference between the first ring 112a and the third ring 112c is smaller than in the case of Figure 3 described above, and an equipotential line shape is formed such that there are fewer equipotential lines passing between the first ring 112a and the third ring 112c than in the case of Figure 3 described above. As a result, as shown in the orbital 320 of the Ar ion in Figure 4, the incident angle of the Ar ion near the outer circumference of the substrate W can be made almost vertical. In addition, there are more equipotential lines passing over the third ring 112c than in the case of Figure 3 described above. For this reason, the thickness of the sheath above the third ring 112c is thicker than in the case of Figure 3 described above.

[0036] Figure 5 shows the orbital 310 of the Ar ion when the potential of the third ring 112c is -500V. In this case, on the inner circumference side of the substrate W (left side of Figure 5), equipotential lines are arranged almost uniformly in the height direction. On the other hand, on the outer circumference side of the substrate W (right side of 150mm in Figure 5), the potential difference between the first ring 112a and the third ring 112c is smaller than in the cases of Figures 3 and 4 described above, and an equipotential line shape is formed such that there are fewer equipotential lines passing between the first ring 112a and the third ring 112c than in the cases of Figures 3 and 4 described above. As a result, as shown in the orbital 330 of the Ar ion in Figure 5, the incident angle of the Ar ion near the outer circumference of the substrate W can be made outward. In addition, there are more equipotential lines passing over the third ring 112c than in the case of Figure 4 described above. For this reason, the thickness of the sheath above the third ring 112c is thicker than in the case of Figure 4 described above.

[0037] Figure 6 is an example of a graph showing the simulation results shown in Figures 3 to 5. The horizontal axis represents the radial position R [mm] from the center of the substrate W, which has a radius of 150 mm, and the vertical axis represents the angle of incidence (Tilting) [deg] of Ar ions onto the substrate W. Note that a negative value on the vertical axis of the angle of incidence of Ar ions indicates that the ions are tilted towards the inner circumference of the substrate W, and a positive value indicates that the ions are tilted towards the outer circumference of the substrate W.

[0038] Furthermore, the incident angle of Ar ions when the potential of the third ring 112c is -100V (see Figure 3) is shown by a solid line, the incident angle of Ar ions when the potential of the third ring 112c is -300V (see Figure 4) is shown by a dashed line, and the incident angle of Ar ions when the potential of the third ring 112c is -500V (see Figure 5) is shown by a dashed line.

[0039] As shown in Figures 3 to 5 and 6, by changing the potential of the third ring 112c, the thickness of the sheath on the third ring 112c can be changed, and the state of the equipotential lines passing between the first ring 112a and the third ring 112c can be changed. This makes it possible to control the incident angle (tilting) of Ar ions at the outer periphery of the substrate W.

[0040] For example, by increasing the height of the third ring 112c, the incident angle of Ar ions at the outer periphery of the substrate W is shifted outward. In this case, by applying a DC signal to the third ring 112c such that the potential difference between the first ring 112a and the third ring 112c becomes large (see Figure 3), the incident angle of Ar ions can be shifted inward. This makes the incident angle of Ar ions incident on the outer periphery of the substrate W closer to vertical.

[0041] Furthermore, plasma treatment causes the third ring 112c to wear down, reducing its thickness in the height direction, which shifts the incident angle of Ar ions at the outer periphery of the substrate W inward. In this case, by applying a DC signal to the third ring 112c such that the potential difference between the first ring 112a and the third ring 112c becomes small (see Figure 5), the incident angle of Ar ions can be shifted outward. This makes the incident angle of Ar ions incident at the outer periphery of the substrate W closer to vertical.

[0042] Here, the ring assembly of the plasma processing apparatus according to the reference example will be described. The ring assembly according to the reference example has an annular member (corresponding to the first ring 112a shown in Figure 2) made of a conductive material that is arranged to surround the substrate W. In addition, in the ring assembly according to the reference example, the thickness of the sheath on the annular member is increased by applying a voltage directly to the annular member, thereby controlling the incident angle of ions on the outer periphery of the substrate W.

[0043] However, in the ring assembly configuration shown in the reference example, applying a voltage to the annular member can shift the incident angle of Ar ions incident on the outer periphery of the substrate W outward, but it cannot shift it inward. Therefore, it is not possible to correct the incident angle of Ar ions, which has been shifted outward by increasing the height of the annular member, by applying a voltage.

[0044] In contrast, the configuration of the ring assembly 112 in the first embodiment allows for the inclination angle of Ar ions incident on the outer periphery of the substrate W to be controlled inward and outward. As a result, even if the thickness of the third ring 112c, which is consumed by plasma processing, is increased, the inclination angle of the Ar ions can be controlled to be approximately vertical, thereby extending the maintenance interval of the ring assembly 112. In other words, the productivity of the plasma processing apparatus 1 can be improved.

[0045] Furthermore, in the ring assembly configuration shown in the reference example, if the potential difference between the substrate W and the annular member becomes large, there is a risk of discharge occurring between the substrate W and the annular member. Also, under processing conditions where a large amount of reaction by-products are generated during the processing of the substrate W, the risk of discharge occurring between the substrate W and the annular member increases. In addition, a potential difference between the annular member and the base 1110 may cause a potential difference within the gas supply path 113, which may lead to discharge occurring within the gas supply path 113.

[0046] In contrast, in the configuration of the ring assembly 112 of the first embodiment, a voltage is applied to the third ring 112c. Furthermore, the inner diameter of the third ring 112c is formed to be larger than the inner diameter of the first ring 112a, which is arranged to surround the substrate W. That is, in the radial direction of the substrate W, the distance from the substrate W to the third ring 112c is longer than the distance from the substrate W to the first ring 112a. In addition, the third ring 112c is also positioned away from the substrate W in the height direction. This makes it possible to suppress the occurrence of discharge between the substrate W and the third ring 112c. Furthermore, it is possible to suppress the occurrence of discharge within the gas supply passage 113.

[0047] In other words, the ring assembly 112 of the first embodiment can increase the potential difference with the substrate W while preventing the occurrence of discharge, compared to the ring assembly of the reference example. This expands the control range of the ion incident angle (tilting).

[0048] Figure 7 is an example of a diagram illustrating an example configuration of a capacitively coupled plasma processing apparatus 1 according to the second embodiment. Figure 8 is an example of a cross-sectional view of the substrate support portion 11 in the plasma processing apparatus 1 according to the second embodiment.

[0049] That is, the power supply 30 may include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generation unit 32a, a second DC generation unit 32b, a third DC generation unit 32c, and a fourth DC generation unit 32d. In one embodiment, the fourth DC generation unit 32d is connected to the first ring 112a of the ring assembly 112 and is configured to generate a fourth DC signal. The generated fourth bias DC signal is applied to the first ring 112a of the ring assembly 112. In the ring assembly 112 according to the second embodiment, the third ring 112c is an example of a potential forming unit.

[0050] Figure 9 shows an example of simulation results illustrating ion orbitals near the outer periphery of the substrate W. The horizontal axis represents the radial position R [mm] from the center of the substrate W, and the vertical axis represents the height direction. In Figure 9, the potential of the substrate W is -100V, the potential of the first ring 112a is -20V, and the potential of the third ring 112c is -100V. An example of equipotential lines when Ar gas is supplied from the gas supply unit 20 via the showerhead 13 to generate an Ar gas plasma is shown as a dashed line.

[0051] The third DC generation unit 32c controls the potential of the third ring 112c, and the fourth DC generation unit 32d controls the potential of the first ring 112a, thereby further improving the controllability of the equipotential line passing between the first ring 112a and the third ring 112c. As a result, by changing the potentials of the first ring 112a and the third ring 112c, the controllability of the incident angle (tilting) of Ar ions at the outer periphery of the substrate W can be further improved, as shown in the Ar ion orbital 340 in Figure 9.

[0052] Furthermore, the fourth DC generation unit 32d controls the potential of the first ring 112a, thereby controlling the potential difference between the first ring 112a and the substrate W. As a result, as shown in Figure 9, Ar ions can be directed to the back side of the substrate W, and Ar ions can be incident on the outer periphery of the back side of the substrate W. Here, reaction byproducts adhering to the outer periphery of the back side of the substrate W can cause electric field concentration and may generate a discharge between the substrate W and the first ring 112a. By incidenting Ar ions on the back side of the substrate W, reaction byproducts adhering to the back side of the substrate W can be removed. This suppresses the occurrence of discharge.

[0053] Furthermore, Ar ions can be directed to the back side of the substrate W, causing them to be incident on the side surface of the electrostatic chuck 1111. This makes it possible to remove reaction by-products adhering to the side surface of the electrostatic chuck 1111. This suppresses the generation of electrical discharge.

[0054] Although the explanation described uses a configuration in which DC signals are applied to the third ring 112c and the first ring 112a from a DC power supply 32, the system is not limited to this configuration. A configuration in which RF signals are applied to the third ring 112c and the first ring 112a from an RF power supply (not shown) is also possible.

[0055] Figure 10 is an example of a cross-sectional view of the substrate support portion 11 in the plasma processing apparatus 1 according to the third embodiment. In the ring assembly 112 according to the third embodiment, an electrode 112d is formed within the second ring 112b. In the ring assembly 112 according to the third embodiment, the electrode 112d is an example of a potential forming portion. The third DC generation unit 32c applies a DC signal to the electrode 112d. By forming a capacitor between the electrode 112d and the third ring 112c, a potential is generated in the third ring 112c. As a result, the third DC generation unit 32c controls the potential of the third ring 112c, thereby controlling the state of equipotential lines and controlling the incident angle (tilting) of Ar ions at the outer periphery of the substrate W.

[0056] Figure 11 is an example of a cross-sectional view of the substrate support portion 11 in the plasma processing apparatus 1 according to the fourth embodiment. In the ring assembly 112 according to the fourth embodiment, an electrode layer 112e is formed on the surface of the second ring 112b. In the ring assembly 112 according to the fourth embodiment, the electrode layer 112e is an example of a potential forming portion. The third DC generation unit 32c applies a DC signal to the electrode layer 112e. The electrode layer 112e is a metal film formed on the upper surface of the second ring 112b. By forming a capacitor between the electrode 112d and the third ring 112c, a potential is generated in the third ring 112c. As a result, the third DC generation unit 32c controls the potential of the third ring 112c, thereby controlling the state of equipotential lines and controlling the incident angle (tilting) of Ar ions at the outer periphery of the substrate W.

[0057] Figure 12 is an example of a cross-sectional view of the substrate support section 11 in the plasma processing apparatus 1 according to the fifth embodiment. In the ring assembly 112 according to the fifth embodiment, a plurality of third rings 112c are provided in the height direction. In the example shown in Figure 12, the third rings 112c are provided in four stages, numbered 112c1 to 112c4. In the ring assembly 112 according to the fifth embodiment, the third rings 112c1 to 112c4 are an example of a potential forming section.

[0058] Furthermore, the third DC generation unit 32c has third DC generation units 32c1 to 32c4 that can individually apply DC signals to the third rings 112c1 to 112c4. The number of DC generation units 32c1 to 32c4 may be reduced by connecting multiple third rings 112c1 to 112c4 via a voltage divider.

[0059] Plasma 200 is generated between the lower surface 131 of the shower head 13 and the substrate W. Furthermore, the plasma 200 is confined in the circumferential direction by the formation of a sheath around the third rings 112c1 to 112c4. This increases the density of the plasma 200 and improves the etching rate.

[0060] Furthermore, as the density of the plasma 200 increases, the impedance of the path from the first ring 112a to the upper electrode (showerhead 13) increases. This increases the efficiency of using the RF signal contributing to the plasma 200. As a result, the density of the plasma 200 increases, and the etching rate improves.

[0061] Furthermore, the shape of the plasma 200 can be controlled by the voltage applied to the third rings 112c1 to 112c4.

[0062] Next, the height position of the third ring 112c in the ring assembly 112 according to the first embodiment shown in Figure 2 will be further explained using Figure 13. Figure 13 is an example of a graph showing the relationship between the height position of the third ring 112c and discharge. The horizontal axis shows the distance from the top surface of the first ring 112a to the bottom surface of the third ring 112c (ring distance) [mm]. The vertical axis shows the value [V / mm] obtained by dividing the potential difference between the first ring 112a and the third ring 112c (ring potential difference) by the distance to the top surface (ring distance) [mm]. In the graph, the shaded area is the area where discharge occurs.

[0063] As shown in Figure 13, by setting the distance from the upper surface of the first ring 112a to the lower surface of the third ring 112c to 1.25 mm or more, discharge between the first ring 112a and the third ring 112c can be prevented. Therefore, by setting the distance D (see Figure 2) from the upper surface of the substrate W to the lower surface of the third ring 112c to 1.25 mm or more, discharge between the substrate W and the third ring 112c can be prevented.

[0064] Furthermore, if the heights of the second ring 112b and the third ring 112c increase, reaction by-products will adhere to the stepped portion between the first ring 112a and the second ring 112b and the third ring 112c. In addition, the adhered reaction by-products may peel off and scatter onto the substrate W, potentially becoming particles. Therefore, by setting the distance from the upper surface of the first ring 112a to the lower surface of the third ring 112c to 2.00 mm or less, the adhesion of reaction by-products at the stepped portion can be suppressed, and the scattering of peeled-off reaction by-products onto the substrate W can be suppressed.

[0065] While embodiments of the plasma processing system have been described above, this disclosure is not limited to the embodiments described above, and various modifications and improvements are possible within the scope of the gist of this disclosure as described in the claims. [Explanation of Symbols]

[0066] W board 1. Plasma processing equipment 2 Control Unit 10 Plasma processing chamber 10s Plasma Processing Space 11. Substrate support section 111 Main body 112 Ring Assembly 112a First Ring 112b Second Ring 112c Third Ring 112d electrode 112e Electrode layer 113 Gas supply lines 114 Gas supply sources 1110 base 1111 Electrostatic Chuck 20 Gas Supply Department 30 power supply 31 RF power supply 32 DC power supply 40 Exhaust System

Claims

1. A plasma processing chamber for housing the substrate, A ring assembly provided around the substrate within the plasma processing chamber, The aforementioned substrate is surrounded by a first ring, which is an annular shape formed of a conductive material, A second ring, which is an annular shape and made of a dielectric material, is placed on the first ring, A third ring, which is an annular shape and is positioned on the second ring and is made of a conductive material, The ring assembly comprises an element formed of a conductive material, configured to receive an applied potential, distinct from the third ring, wherein the element is positioned inside or on the second ring without contact with the first ring, and the lower surface of the element is positioned higher than the upper surface of the substrate. The system comprises a power supply that provides a DC signal or an RF signal to the aforementioned element. Circuit board processing equipment.

2. The distance between the substrate and the lower surface of the element is 1.25 mm or more. The substrate processing apparatus according to claim 1.

3. The ring assembly is The electrodes embedded within the aforementioned second ring and forming the element are The substrate processing apparatus according to claim 1.

4. The ring assembly is Having an electrode layer formed on the second ring and forming the element, The substrate processing apparatus according to claim 1.

5. A plasma processing chamber for housing a substrate, A ring assembly provided around the substrate within the plasma processing chamber, Dielectrics and An element disposed on the dielectric, formed of a conductive material, and configured to receive an applied potential, wherein the lower surface of the element is positioned higher than the upper surface of the substrate, The aforementioned substrate is surrounded by a first ring, which is an annular shape formed of a conductive material, A ring-shaped second ring, which is the dielectric, is placed on the first ring, The ring assembly comprises a plurality of third rings, which are positioned on the second ring, have an annular shape, and form the element, The system comprises a power supply that provides a DC signal or an RF signal to the aforementioned element. Circuit board processing equipment.

6. The inner diameter of the second ring is formed to be larger than the inner diameter of the first ring. A substrate processing apparatus according to any one of claims 1 to 5.

7. The inner diameter of the third ring is formed to be larger than the inner diameter of the first ring. A substrate processing apparatus according to any one of claims 1 to 5.

8. The inner diameter of the third ring is formed to be equal to the inner diameter of the second ring. A substrate processing apparatus according to any one of claims 1 to 5.

9. The element is an electrode disposed inside or on the second ring. The substrate processing apparatus according to claim 1.

10. The distance from the upper surface of the first ring to the lower surface of the third ring is 1.25 mm or more and 2.00 mm or less. A substrate processing apparatus according to any one of claims 1 to 5.

11. A plasma processing chamber for housing the substrate, A ring assembly provided around the substrate within the plasma processing chamber, The aforementioned substrate is surrounded by a first ring, which is an annular shape formed of a conductive material, A second ring, which is an annular shape and made of a dielectric material, is placed on the first ring, A third ring, which is an annular shape and is positioned on the second ring and is made of a conductive material, The ring assembly comprises an element formed of a conductive material and configured to directly receive an applied potential, wherein the element is positioned inside or on the second ring without contacting the first ring, and the lower surface of the element is positioned higher than the upper surface of the substrate. The system comprises a power supply that provides a DC signal or an RF signal as an electric potential to the aforementioned element, Circuit board processing equipment.

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