Electrostatic chuck

Abstract

An electrostatic chuck device provided with: an electrostatic chuck plate having a dielectric substrate, which has a placement surface on which a wafer is placed, and an electrode, which is positioned in the interior of the dielectric substrate; a focus ring that is installed at the outer peripheral portion of the electrostatic chuck plate, and surrounds the placement surface; and a power supply connection part for connecting the electrode and a power supply. The electrostatic chuck plate has a first electrode which, in a planar view, is positioned in a region overlapping the placement surface, and a second electrode which, in a planar view, is positioned in a region overlapping the focus ring. The power supply connection part includes power supply wiring electrically connecting the first electrode and the second electrode via a current adjustment device.

Description

[Technical Field]

[0001] The present invention relates to an electrostatic chuck device. This application claims priority based on Japanese Patent Application No. 2020-111805, filed on June 29, 2020, the contents of which are incorporated herein by reference. [Background technology]

[0002] As an electrostatic chuck device for supporting a semiconductor wafer, a configuration in which an electrostatic chuck capable of attracting a focus ring is installed on a metal susceptor is known, as described in Patent Document 1. A power supply device for generating plasma is connected to the susceptor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-134375 Summary of the Invention [Problem to be solved by the invention]

[0004] In electrostatic chuck devices with a focus ring surrounding the wafer, the focus ring thins over time. As the focus ring thins, the capacitance between the plasma and the electrode changes, causing the plasma to become non-uniform. This can lead to issues such as a larger difference in etching rate between the center and periphery of the wafer, and an increased rate of focus ring wear.

[0005] An object of the present invention is to provide an electrostatic chuck device capable of controlling plasma around a focus ring. [Means for solving the problem]

[0006] According to a first aspect of the present invention, there is provided an electrostatic chuck device including: a dielectric substrate having a mounting surface on which a wafer is mounted; an electrostatic chuck plate having an electrode located inside the dielectric substrate; a focus ring disposed on the outer periphery of the electrostatic chuck plate and surrounding the mounting surface; and a power supply connector connecting the electrode to a power source. The electrostatic chuck plate has a first electrode located in an area overlapping the mounting surface in a plan view, and a second electrode located in an area overlapping the focus ring in a plan view. The power supply connector includes a power supply wiring that electrically connects the first electrode to the second electrode via a current regulator.

[0007] The electrostatic chuck device according to the first aspect of the present invention preferably includes the following features. Two or more of the following features may also be preferably combined as needed. The electrostatic chuck may have a side cover surrounding the electrostatic chuck plate from the outside in the radial direction, and the current regulator may be located on the back side of the dielectric substrate and inside the side cover.

[0008] The current regulator may include a variable resistor.

[0009] The current regulator may include a constant current circuit.

[0010] The second electrode may be divided into a plurality of electrode portions arranged along an extension direction of the focus ring, and each of the electrode portions may be connected to the first electrode via the power supply wiring.

[0011] The electrostatic chuck may be configured to include a metal base supporting the electrostatic chuck plate from a back surface side opposite the mounting surface, and the current regulator may be located on the opposite side of the metal base from the electrostatic chuck plate and inside the side cover. [Effects of the Invention]

[0012] According to one aspect of the present invention, an electrostatic chuck device capable of controlling plasma around a focus ring can be provided. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a preferred example of a plasma processing apparatus equipped with an electrostatic chuck device according to an embodiment. [Figure 2] FIG. 2 is a schematic plan view of the electrostatic chuck plate as viewed from the back surface side. [Figure 3] FIG. 3 is a diagram showing a constant current circuit applicable to a current regulator. [Figure 4] FIG. 4 is a diagram showing a constant current circuit applicable to a current regulator. [Figure 5] FIG. 5 is a diagram showing a constant current circuit applicable to a current regulator. DETAILED DESCRIPTION OF THE INVENTION

[0014] Preferred examples of each embodiment of the electrostatic chuck device of the present invention will be described below with reference to the drawings. In all of the following drawings, the dimensions and proportions of each component may be displayed differently as appropriate to make the drawings easier to understand. The number, position, size, members, etc. may be omitted, added, changed, substituted, replaced, or otherwise modified within the scope of the present invention.

[0015] Fig. 1 is a schematic cross-sectional view of a plasma processing apparatus equipped with an electrostatic chuck device according to this embodiment, and Fig. 2 is a plan view of an electrostatic chuck plate as viewed from the back surface side. The plasma processing apparatus 100 includes a vacuum vessel 101 and an electrostatic chuck device 1 fixed inside the vacuum vessel 101. The vacuum vessel 101 has a bottom wall 102, a cylindrical side wall 103 extending upward from the outer peripheral edge of the bottom wall 102, and a top wall 104 fixed to the upper end of the side wall 103 and facing the bottom wall 102 in the vertical direction.

[0016] An electrostatic chuck device 1 is fixed to the bottom of the internal space of a vacuum vessel 101. The electrostatic chuck device 1 is fixed to the inner surface (the upper surface in the figure) of a bottom wall 102. The electrostatic chuck device 1 of this embodiment is placed in the vacuum vessel 101 with a mounting surface 2a on which a wafer W is placed facing upward. The arrangement of the electrostatic chuck device 1 is one example, and other arrangements may also be used.

[0017] The bottom wall 102 of the vacuum vessel 101 has an opening 102a penetrating the bottom wall 102 in the thickness direction, and an exhaust port 102b. The electrostatic chuck device 1 closes the opening 102a from the inside (the upper side in the figure) of the vacuum vessel 101. The exhaust port 102b is located on the side of the electrostatic chuck device 1. A vacuum pump (not shown) is connected to the exhaust port 102b.

[0018] The electrostatic chuck device 1 includes an electrostatic chuck plate 10 that attracts and supports a wafer W, and a metal base 11 that supports the electrostatic chuck plate 10. A focus ring 5 that surrounds a mounting surface 2a (wafer W) in a plan view is disposed on the outer periphery of the upper surface of the electrostatic chuck plate 10.

[0019] The electrostatic chuck plate 10 includes a dielectric substrate 2 having a mounting surface 2 a on which a wafer W is placed, and an attraction electrode 6 located inside the dielectric substrate 2 . The dielectric substrate 2 has a circular shape in a plan view. The dielectric substrate 2 is made of a composite sintered body that has mechanical strength and durability against corrosive gases and their plasma. As a dielectric material that constitutes the dielectric substrate 2, ceramics that have mechanical strength and durability against corrosive gases and their plasma are preferably used. As the ceramic that constitutes the dielectric substrate 2, for example, aluminum oxide (Al2O3) sintered body, aluminum nitride (AlN) sintered body, aluminum oxide (Al2O3)-silicon carbide (SiC) composite sintered body, etc. are preferably used.

[0020] The upper surface of the dielectric substrate 2 is a mounting surface 2a on which the wafer W is placed. A plurality of protrusions (not shown) are formed at predetermined intervals on the mounting surface 2a. Each of the plurality of protrusions has a diameter smaller than the thickness of the wafer W. The plurality of protrusions on the mounting surface 2a support the wafer W. The shape of the protrusions can be selected arbitrarily, and may be, for example, cylindrical.

[0021] The electrostatic chuck plate 10 has a ring attraction region 2d radially outward from the mounting surface 2a of the dielectric substrate 2. In this embodiment, the upper surface of the ring attraction region 2d is located lower than the mounting surface 2a in the vertical direction in the figure. A focus ring 5 is placed on the ring attraction region 2d. As shown in FIG. 1, the outer periphery of the focus ring 5 placed on the ring attraction region 2d protrudes radially outward from the dielectric substrate 2. The outer periphery of the focus ring 5 protruding outward from the dielectric substrate 2 is placed in a notch 4b of a side cover 4, which will be described later. The height position (vertical position) of the upper surface of the focus ring 5 is approximately the same as the height position of the upper surface of the wafer W placed on the mounting surface 2a.

[0022] Focus ring 5 is made of, for example, a material having electrical conductivity equivalent to that of wafer W placed on mounting surface 2a. Specifically, silicon, silicon carbide, quartz, alumina, or the like can be used as the material for focus ring 5. By providing focus ring 5, the electrical environment relative to the plasma at the peripheral portion of wafer W can be made roughly the same as that of wafer W. This reduces the likelihood of differences or biases in plasma processing between the center and peripheral portions of wafer W.

[0023] The chucking electrode 6 is located inside the dielectric substrate 2. The chucking electrode 6 includes a first electrode 6a located in a region overlapping with the mounting surface in a plan view, and a second electrode 6b located in a region overlapping with the focus ring 5 in a plan view. That is, the electrostatic chuck plate 10 has the first electrode 6a and the second electrode 6b.

[0024] 2, the first electrode 6a has a circular shape in a plan view. The first electrode 6a has a diameter slightly smaller than that of the mounting surface 2a and the wafer W. The first electrode 6a may be divided into a plurality of electrode portions. The plurality of electrode portions may be arranged side by side in the radial direction of the dielectric substrate 2, in the circumferential direction, or in both the radial and circumferential directions.

[0025] As shown in FIG. 2, the second electrode 6b has an annular shape extending along the outer periphery of the dielectric substrate 2. The second electrode 6b is composed of six electrode portions 61-66 arranged in the circumferential direction of the dielectric substrate 2. The six electrode portions 61-66 have the same size and shape and are arranged at equal intervals along the outer periphery of the first electrode 6a. The second electrode 6b is arranged in an area overlapping with the ring adsorption area 2d and adsorbs the focus ring 5. The division of the second electrode 6b is not limited to the example shown in Fig. 2. The second electrode 6b may be divided into a plurality of annular electrode portions. Alternatively, the six electrode portions 61 to 66 may be further divided in the radial direction.

[0026] As shown in FIG. 1, the height position (vertical position) of the second electrode 6b is lower than the height position of the first electrode 6a. In this embodiment, the thickness of the focus ring 5 is greater than the thickness of the wafer W. The height difference between the mounting surface 2a of the dielectric substrate 2 and the ring attraction region 2d corresponds to the difference in thickness between the focus ring 5 and the wafer W. By adjusting the height positions of the first electrode 6a and the second electrode 6b, the attraction force between the first electrode 6a and the wafer W and the attraction force between the second electrode 6b and the focus ring 5 can be adjusted within appropriate ranges.

[0027] The dielectric substrate 2 has a rear surface 2b bonded to the upper surface of the metal base 11. The metal base 11 is a metal member having a disk shape in a plan view. The metal base 11 is made of, for example, an aluminum alloy. The metal base 11 supports the electrostatic chuck plate 10 from the back surface 2b side. The metal base 11 is supported from below by a cylindrical support member 3 that extends downward from the outer periphery of the back surface of the metal base 11. A cylindrical side cover 4 is disposed radially outward of the electrostatic chuck plate 10, the metal base 11, and the support member 3 to surround them.

[0028] The metal base 11 has a heater element 9 arranged throughout its interior. The heater element 9 and the metal base 11 are insulated from each other. A heater power supply (not shown) is connected to the heater element 9. The heater element 9 may be provided outside the metal base 11. The heater element 9 may be disposed inside the electrostatic chuck plate 10. The heater element 9 may be disposed between the electrostatic chuck plate 10 and the metal base 11.

[0029] The support member 3 is cylindrical and extends from the outer circumferential edge of the lower surface of the metal base 11 toward the bottom wall 102. The support member 3 is made of an insulating material such as alumina. The lower end of the support member 3 is fixed to the upper surface of the bottom wall 102. The support member 3 is disposed along the periphery of the opening 102a of the bottom wall 102. The gap between the support member 3 and the bottom wall 102 is airtightly sealed by, for example, an O-ring.

[0030] The space inside the support member 3 is connected to the space outside the vacuum vessel 101 via an opening 102a in the bottom wall 102. The back surface 2b of the dielectric substrate 2 is exposed in the space inside the support member 3. An operator can access the back surface 2b of the dielectric substrate 2 through the opening 102a in the bottom wall 102.

[0031] The side cover 4 is a cylindrical member extending in the vertical direction. The side cover 4 covers the outside of the support member 3. In this embodiment, the side cover 4 faces the side end surface 2c of the dielectric substrate 2 and the outer peripheral surface 3b of the support member 3 in the radial direction. The side cover 4 protects the side end surface 2c of the dielectric substrate 2 and the outer peripheral surface 3b of the support member 3 from plasma. The side cover 4 is made of, for example, alumina, quartz, or the like. There are no particular limitations on the material of the side cover 4 as long as it has the required plasma resistance. The electrostatic chuck device 1 may also be configured without the side cover 4.

[0032] An upper end 4a of the side cover 4 is located to the side of the dielectric substrate 2. The side cover 4 has a notch 4b extending along the inner peripheral edge at an inner corner of the upper end 4a. The outer peripheral portion of the focus ring 5 is disposed inside the notch 4b. The height position (vertical position in the figure) of the upper end face 4c of the side cover 4 substantially coincides with the height position of the upper surface of the focus ring 5 and the height position of the upper surface of the wafer W.

[0033] In the electrostatic chuck device 1, the electrostatic chuck plate 10 and the metal base 11 have a power supply connection hole 12a and a plurality of power supply connection holes 12b that open to a lower surface 11a of the metal base 11. The power supply connection hole 12a is located in the center of the metal base 11 in a plan view. The power supply connection hole 12a extends upward from the lower surface 11a and reaches the lower surface of the first electrode 6a.

[0034] The plurality of power supply connection holes 12b are provided at six locations corresponding to the six electrode portions 61 to 66. Each of the power supply connection holes 12b extends upward from the lower surface 11a of the metal base 11 and reaches the lower surface of each of the electrode portions 61 to 66. In the present embodiment, the six power supply connection holes 12b are arranged at equal intervals in the circumferential direction of the electrostatic chuck plate 10.

[0035] Cylindrical insulating tubes (not shown) are embedded in the power supply connection holes 12a and 12b. The insulating tubes are made of, for example, alumina. Power supply wires 151-157 of the power supply connection part 50, which will be described later, are inserted inside the insulating tubes and connected to the first electrodes 6a and 6b at the bottoms (upper ends) of the power supply connection holes 12a and 12b. The power supply wires 151-157 are connected to the first electrode 6a and the second electrode 6b by, for example, soldering or welding. The power supply wires 151-157 may be connected to the first electrode 6a and the second electrode 6b via connectors.

[0036] As shown in FIG. 1, the power supply device 110 includes a high-frequency power supply 111 for plasma excitation, a matching box 112, a DC power supply 113 for electrostatic attraction, a resistor 114, a high-frequency power supply 115 for substrate bias, and a matching box 116.

[0037] A high-frequency power supply 111 for plasma excitation is electrically connected via a matching box 112 to a main power feed rod 8 extending downward from the bottom surface of the metal base 11. The main power feed rod 8 is a rod-shaped member made of a metal such as aluminum, copper, or stainless steel. The upper end of the main power feed rod 8 is fixed to the bottom surface of the metal base 11. High-frequency power output from the high-frequency power supply 111 is supplied to the metal base 11 via the main power feed rod 8.

[0038] A DC power supply 113 for electrostatic attraction is connected to a power supply wiring 150 via a resistor 114. A high frequency power supply 115 for substrate bias is connected to the power supply wiring 150 via a matching unit .

[0039] 1 and 2, the electrostatic chuck device 1 has a power supply connection unit 50 that connects the power supply unit 110 and the chucking electrode 6. The power supply connection unit 50 has eight power supply wires 150 to 157 and six current regulators 51 to 56. The power supply connection unit 50 is connected to the power supply unit 110 via the power supply wires 150. In this embodiment, the power supply wires 150 are electrically connected to a DC power supply 113 for electrostatic chucking and a high-frequency power supply 115 for substrate bias, both of which are included in the power supply unit 110.

[0040] The power supply wiring 150 is electrically connected to seven power supply wirings 151 to 157 at a node N. In FIG. 1, for convenience of illustration, the node N is shown divided into two parts. As shown in FIG. 2, the six power supply wirings 151 to 156 extend radially from the node N toward the outer periphery of the electrostatic chuck plate 10. As shown in FIG. 1, the power supply wiring 157 is inserted from the node N into the power supply connection hole 12a and connected to the first electrode 6a.

[0041] The six power supply wires 151 to 156 are inserted into different power supply connection holes 12b at the outer periphery of the electrostatic chuck plate 10. The power supply wire 151 is electrically connected to the electrode portion 61 of the second electrode 6b. Similarly, the power supply wire 152 is electrically connected to the electrode portion 62, the power supply wire 153 is electrically connected to the electrode portion 63, the power supply wire 154 is electrically connected to the electrode portion 64, the power supply wire 155 is electrically connected to the electrode portion 65, and the power supply wire 156 is electrically connected to the electrode portion 66.

[0042] Current regulator 51 is connected between node N of power supply wiring 151 and second electrode 6b. Similarly, current regulators 52 to 56 are connected between node N of power supply wiring 152 to 156 and second electrode 6b, respectively.

[0043] With the above circuit configuration, electrode portion 61 of second electrode 6b is electrically connected to first electrode 6a via power supply wiring 151, 157 and current regulator 51. Similarly, electrode portion 62 is electrically connected to first electrode 6a via power supply wiring 152, 157 and current regulator 52. Other electrode portions 63 to 66 are also electrically connected to first electrode 6a via power supply wiring 153 to 157 and current regulators 53 to 56, respectively. That is, the electrostatic chuck device 1 has power supply wirings 151 to 157 that connect the first electrode 6a and the second electrode 6b via any of the current regulators 51 to 56.

[0044] Power supply device 110 is connected to node N via power supply wiring 150. Therefore, power input from DC power supply 113 and high frequency power supply 115 is supplied to first electrode 6a via power supply wiring 150, 157. On the other hand, power whose current is controlled by current regulators 51-56 is supplied to electrode portions 61-66 of second electrode 6b via power supply wiring 151-156, respectively.

[0045] In the electrostatic chuck device 1, the focus ring 5 becomes thinner with the passage of time. As a result, the capacitance between the metal base 11 and the plasma generation space becomes relatively larger, and the high-frequency power input to the region where the focus ring 5 is located increases. This causes a change in the plasma distribution, increasing the difference in etching rate between the center and the outer periphery of the wafer W and increasing the wear rate of the focus ring 5.

[0046] Therefore, in the electrostatic chuck device 1 of this embodiment, the first electrode 6a located below the wafer W and the second electrode 6b located below the focus ring 5 are connected via current regulators 51 to 56, and are connected to the power supply device 110 at a node N located closer to the first electrode 6a than the current regulators 51 to 56.

[0047] According to this configuration, the current regulators 51 to 56 can adjust the current flowing from the power supply device 110 to the second electrode 6b. Therefore, when the current flowing to the second electrode 6b increases due to wear of the focus ring 5, the current regulators 51 to 56 can suppress the current, thereby preventing excessive high-frequency power from being input to the position of the focus ring 5 and maintaining a good plasma distribution. The electrostatic chuck device 1 of this embodiment enables plasma control around the focus ring 5.

[0048] 3 to 5 are diagrams showing constant current circuits applicable to current regulators 51 to 56. FIG.

[0049] 3 is a circuit in which a resistor 201 and a PTC thermistor (Positive Temperature Coefficient Thermistor) 202 are connected in parallel. In the constant current circuit 200, when the current flowing from the input terminal IN to the output terminal OUT increases, the PTC thermistor 202 generates heat by itself and becomes highly resistant, and the current flowing through the constant current circuit 200 decreases. The amount of current flowing through the constant current circuit 200 can be adjusted by the size of the resistor 201. By using constant current circuit 200 as current regulators 51-56, the current flowing through power supply wiring 151-156 can be controlled within a predetermined range, thereby preventing the plasma distribution around focus ring 5 from becoming non-uniform.

[0050] 4 includes a first transistor 301, a resistor 302, and a second transistor 303, which are connected in this order from the input terminal IN side. The first transistor 301 and the second transistor 303 are both N-channel depletion-mode field-effect transistors.

[0051] The drain of the first transistor 301 is connected to the input terminal IN. The source of the first transistor 301 is connected to the IN terminal of the resistor 302 and the gate of the second transistor 303. The gate of the first transistor is connected to the OUT terminal of the resistor 302 and the source of the second transistor 303. The drain of the second transistor 303 is connected to the output terminal OUT. The gate of the second transistor 303 is connected to the IN terminal of the resistor 302 and the source of the first transistor 301. The two diodes shown in FIG. 4 are parasitic diodes of the first transistor 301 and the second transistor 303.

[0052] In the constant current circuit 300, the first transistor 301 is a depletion-mode FET and a normally-on switch. A current input from the input terminal IN flows from the drain to the source of the first transistor 301 and then flows into the resistor 302. The voltage drop across the resistor 302 is input to the gate of the first transistor 301 as a bias voltage. As a result, the gate potential of the first transistor 301 becomes lower than the source potential, and the current flowing between the drain and source decreases to a predetermined value. The current input from the resistor 302 to the source of the second transistor 303 passes through the parasitic diode of the second transistor 303 and is output to the output terminal OUT.

[0053] When a current flows from the output terminal OUT to the input terminal IN through the constant current circuit 300, the second transistor 303 adjusts the current flowing through the constant current circuit 300. The current flowing from the resistor 302 to the first transistor 301 passes through the parasitic diode of the first transistor 301 and is output to the input terminal IN.

[0054] By using the constant current circuit 300 described above as the current regulators 51-56, the currents flowing through the power supply lines 151-156 can be controlled within a predetermined range. Even in a configuration using the constant current circuit 300, it is possible to prevent the plasma distribution around the focus ring 5 from becoming non-uniform.

[0055] 5 includes a first transistor 401, a resistor 402, and a second transistor 403, which are connected in this order from the input terminal IN side. The constant current circuit 400 further includes a first photodiode 404 connected between the gate of the first transistor 401 and the OUT terminal of the resistor 402, and a second photodiode 405 connected between the gate of the second transistor 401 and the IN terminal of the resistor 402. The first transistor 401 and the second transistor 403 are both N-channel enhancement mode field effect transistors.

[0056] The drain of the first transistor 401 is connected to the input terminal IN. The source of the first transistor 401 is connected to the IN terminal of the resistor 402 and the anode of the second photodiode 405. The gate of the first transistor 401 is connected to the cathode of the first photodiode 404.

[0057] The source of the second transistor 403 is connected to the OUT terminal of the resistor 402 and the anode of the first photodiode 404. The drain of the second transistor 403 is connected to the output terminal OUT. The gate of the second transistor 403 is connected to the cathode of the second photodiode 405. The anode of the second photodiode 405 is connected to the IN terminal of the resistor 402 and the source of the first transistor 401. The first transistor 401 and the second transistor 403 each have a parasitic diode.

[0058] The constant current circuit 400 can control the amount of current by a light source device 410 that irradiates light onto a first photodiode 404 and a second photodiode 405. The light source device 410 has a light emitting diode 411 and a control device 412 that drives and controls the light emitting diode 411. The control device 412 can control the brightness of the light emitting diode 411. The light emitted from the light emitting diode 411 is irradiated onto the first photodiode 404 and the second photodiode 405 via, for example, an optical fiber.

[0059] In the constant current circuit 400, the first transistor 401 is an enhancement mode FET and a normally-off switch. When the light source device 410 does not irradiate the first photodiode 404 with light, no current flows through the first transistor 401. When light from the light source device 410 is irradiated onto the first photodiode 404, the cathode potential of the first photodiode 404 is input to the gate of the first transistor 401, turning on the first transistor 401. As a result, a current input from the input terminal IN flows from the drain to the source of the first transistor 401 and into the resistor 402. The voltage drop across resistor 402 is input as a bias voltage to the gate of first transistor 401, so that the gate potential of first transistor 401 becomes lower than the source potential, and the current flowing between the drain and source decreases to a predetermined value. The current input from resistor 402 to the source of second transistor 403 passes through the parasitic diode of second transistor 403 and is output to output terminal OUT.

[0060] When a current flows from the output terminal OUT to the input terminal IN through the constant current circuit 400, the second transistor 403 and the second photodiode 405 adjust the current flowing through the constant current circuit 400. The current flowing from the resistor 402 to the first transistor 401 passes through the parasitic diode of the first transistor 401 and is output to the input terminal IN.

[0061] By using the constant current circuit 400 described above as the current regulators 51-56, the current flowing through the power supply wiring 151-156 can be controlled within a predetermined range. Even in a configuration using the constant current circuit 400, it is possible to prevent the plasma distribution around the focus ring 5 from becoming non-uniform. Furthermore, the constant current circuit 400 can control the amount of current flowing through the constant current circuit 400 depending on the amount of light irradiated from the light source device 410 onto the first photodiode 404 and the second photodiode 405. By using the constant current circuit 400, it is possible to control the plasma around the focus ring 5 with higher precision.

[0062] In this embodiment, the constant current circuits shown in FIGS. 3 to 5 are used as examples of circuits applicable to the current regulators 51 to 56, but the present invention is not limited to these configurations. The current regulators 51 to 56 may be elements that can automatically or manually adjust the current flowing through the power supply wirings 151 to 156. For example, variable capacitors may be used as the current regulators 51 to 56. By electrically or mechanically changing the capacitance of the variable capacitor, the current flowing through the power supply wirings 151 to 156 can be adjusted, thereby maintaining the uniformity of the plasma on the wafer W and the focus ring 5.

[0063] The electrostatic chuck device 1 of this embodiment has a side cover 4 that surrounds the electrostatic chuck plate 10 from the radial outside, and the current adjusters 51 to 56 are located on the rear surface 2b side of the dielectric substrate 2 and inside the side cover 4. Furthermore, in this embodiment, a cylindrical support member 3 is disposed inside the side cover 4, and the current adjusters 51 to 56 are located inside the support member 3. According to this configuration, the current adjusters 51 to 56 are housed in the internal space of the electrostatic chuck device 1, thereby enabling the electrostatic chuck device 1 to be made compact. In addition, since no components are disposed outside the electrostatic chuck device 1, the electrostatic chuck device can be easily installed in a conventional plasma processing apparatus.

[0064] In the electrostatic chuck device 1 of the present embodiment, the constant current circuit 200 shown in Fig. 3 can be used for the current regulators 51 to 56. That is, the electrostatic chuck device 1 can be configured so that the current regulators 51 to 56 include variable resistors. According to this configuration, the current regulator can be configured using a simple circuit. Since the current regulators 51 to 56 can be easily made smaller, the power supply connection portion 50 can be easily disposed on the back surface of the electrostatic chuck plate 10.

[0065] 3 to 5 can be used for the current regulators 51 to 56. By using these constant current circuits 200, 300, and 400 for the current regulators 51 to 56, the current regulators 51 to 56 operate to suppress current changes due to wear of the focus ring 5. This makes it possible to maintain the plasma distribution state for a long period of time.

[0066] 2 , in the electrostatic chuck device 1 of the present embodiment, the second electrode 6b is divided into a plurality of electrode portions 61 to 66 arranged along the extension direction of the focus ring 5, and each of the electrode portions 61 to 66 is connected to the first electrode 6a via power supply wiring 151 to 156. According to this configuration, the plurality of electrode portions 61 to 66 are arranged along the circumferential direction of the electrostatic chuck plate 10, and the current of each of the electrode portions 61 to 66 can be controlled, thereby preventing the plasma from becoming non-uniform in the circumferential direction.

[0067] The electrostatic chuck device 1 of this embodiment has a metal base 11 that supports the electrostatic chuck plate 10 from the back surface 2b side opposite the mounting surface 2a, and the current adjusters 51 to 56 are located on the opposite side of the metal base 11 from the electrostatic chuck plate 10 and inside the side cover 4. According to this configuration, the current adjusters 51 to 56 can be accommodated in the internal space of the electrostatic chuck device 1, thereby making it possible to reduce the size of the electrostatic chuck device 1. Since no components are disposed outside the electrostatic chuck device 1, the electrostatic chuck device 1 can be easily installed in an existing plasma processing apparatus. [Industrial Applicability]

[0068] The present invention can provide an electrostatic chuck device capable of controlling plasma around a focus ring, and an electrostatic chuck that maintains a constant power balance between a substrate and a focus ring. [Explanation of symbols]

[0069] 1...Electrostatic chuck device 2...Dielectric substrate 2a...Placement surface 2b…Back side 2c…Side end surface 2d...Ring adsorption area 3...Support member 3b…Outer surface 4...Side cover 4a...Top end 4b...Notch 4c...Upper end face 5...Focus ring 6...Adsorption electrode 6a…1st electrode 6b…Second electrode 8…Main power supply rod 9...Heater element 10...Electrostatic chuck plate 11...Metal base 11a...Bottom surface 12a...Power connection hole 12b...Power connection hole 50...Power connection 51,52,53,54,55,56…Current regulator 61,62,63,64,65,66...Electrode section 150,151,152,153,154,155,156,157...Power supply wiring 200,300,400…constant current circuit 201...Resistance 202...PTC thermistor (variable resistor) 301...first transistor 302...Resistance 303...Second transistor 401...first transistor 402...Resistance 403...Second transistor 404...First photodiode 405...Second photodiode 410...Light source device 411...Light-emitting diode 412...Control device N...node W...wafer

Claims

1. an electrostatic chuck plate including a dielectric substrate having a mounting surface on which a wafer is placed and an electrode located inside the dielectric substrate; a focus ring disposed on an outer periphery of the electrostatic chuck plate and surrounding the mounting surface; a power supply connection portion that connects the electrode and a power supply; An electrostatic chuck device comprising: the electrostatic chuck plate includes a first electrode located in a region overlapping with the mounting surface in a plan view, and a second electrode located in a region overlapping with the focus ring in a plan view, the power supply connection portion electrically connects the first electrode and the second electrode via a current regulator; the current regulator is a constant current circuit in which a first transistor, a resistor, and a second transistor are connected in this order; the drain of the first transistor is disposed on the input terminal side; a source of the first transistor connected to an IN terminal of the resistor and a gate of the second transistor; a gate of the first transistor connected to an OUT terminal of the resistor and a source of the second transistor; The drain of the second transistor is disposed on the output side, the gate of the second transistor includes a power supply wiring connected to an IN terminal of the resistor and a source of the first transistor; Electrostatic chuck device.

2. a side cover that surrounds the electrostatic chuck plate from the radially outer side; the current regulator is located on the back side of the dielectric substrate and inside the side cover; 2. The electrostatic chuck device according to claim 1.

3. the current regulator includes a constant current circuit; 3. The electrostatic chuck device according to claim 1 or 2.

4. the second electrode is divided into a plurality of electrode portions arranged along an extension direction of the focus ring, Each of the electrode portions is connected to the first electrode via the power supply wiring. The electrostatic chuck device according to any one of claims 1 to 3.

5. a metal base supporting the electrostatic chuck plate from a back surface side opposite to the mounting surface; the current regulator is located on the opposite side of the metal base from the electrostatic chuck plate and inside the side cover; 3. The electrostatic chuck device according to claim 2.

6. the first electrode is a circular electrode in a plan view, the second electrode is an annular electrode divided into multiple parts and extending along the outer periphery of the dielectric substrate; 2. The electrostatic chuck device according to claim 1.

7. The second electrodes have the same size and shape.

7. The electrostatic chuck device according to claim 4 or 6.

8. the constant current circuit includes a first photodiode connected between the gate of the first transistor and an OUT terminal of the resistor, and a second photodiode connected between the gate of the second transistor and an IN terminal of the resistor, a source of the first transistor connected to an IN terminal of the resistor and an anode of the second photodiode; The drain of the first transistor is disposed on the input side, a gate of the first transistor connected to a cathode of the first photodiode; a source of the second transistor connected to an OUT terminal of the resistor and an anode of the first photodiode; The drain of the second transistor is disposed on the output side, a gate of the second transistor connected to a cathode of the second photodiode; an anode of the second photodiode is connected to an IN terminal of the resistor and a source of the first transistor; 2. The electrostatic chuck device according to claim 1.

9. the constant current circuit is capable of controlling the amount of current by a light source device that irradiates light onto the first photodiode and the second photodiode; 9. The electrostatic chuck device according to claim 8.

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