Electrostatic chuck

Abstract

An electrostatic chuck device includes an electrostatic chuck plate having a dielectric substrate with a wafer placement surface and an electrode inside the dielectric substrate, a focus ring disposed at an outer peripheral portion of the electrostatic chuck plate and surrounding the placement surface, and a power supply connection portion connecting the electrode and a power supply. The electrostatic chuck plate has a first electrode in a region overlapping the placement surface in plan view and a second electrode in a region overlapping the focus ring in plan view. The power supply connection portion includes a power supply wiring electrically connecting the first electrode and the second electrode via a current regulator.

Description

Technical Field

[0001] This invention relates to an electrostatic chuck device.

[0002] This application claims priority under Japanese Patent Application No. 2020-111805, filed in Japan on June 29, 2020, the contents of which are incorporated herein by reference. Background Technology

[0003] As an electrostatic chuck device for supporting semiconductor wafers, for example as described in Patent Document 1, there is a known structure in which an electrostatic chuck capable of adsorbing a focusing ring is provided on a metal wafer susceptor. A power supply device for plasma generation is connected to the wafer susceptor.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2012-134375 Summary of the Invention

[0007] The technical problem to be solved by the invention

[0008] In electrostatic chuck devices, when a focusing ring is present around the wafer, the focusing ring thins over time. If the focusing ring thins, the capacitance between the plasma and the electrodes changes, causing the plasma to become non-uniform. Therefore, problems may arise, such as a larger difference in etching rate between the wafer's center and outer periphery, or a faster wear rate of the focusing ring.

[0009] The purpose of this invention is to provide an electrostatic chuck device capable of controlling plasma around a focusing ring.

[0010] means for solving technical problems

[0011] According to a first aspect of the present invention, an electrostatic chuck device is provided, comprising: an electrostatic chuck plate having a dielectric substrate and electrodes located inside the dielectric substrate, the dielectric substrate having a mounting surface for mounting a wafer; a focusing ring disposed on the outer periphery of the electrostatic chuck plate and surrounding the mounting surface; and a power connection portion for connecting the electrodes to a power source. The electrostatic chuck plate has: a first electrode located in a region overlapping the mounting surface when viewed from above; and a second electrode located in a region overlapping the focusing ring when viewed from above. The power connection portion includes a power wiring that electrically connects the first electrode and the second electrode via a current regulator.

[0012] The electrostatic chuck device of the first aspect of the present invention preferably includes the features described below. It is also preferable to combine two or more of the following features as needed.

[0013] It can be configured as follows: having a side cover that surrounds the electrostatic chuck plate from the radial outside, with the current regulator located on the back side of the dielectric substrate and inside the side cover.

[0014] The current regulator can be configured to include a variable resistor.

[0015] The current regulator can be configured to include a constant current circuit.

[0016] The structure can be configured as follows: the second electrode is divided into a plurality of electrode portions arranged along the extension direction of the focusing ring, and each of the electrode portions is connected to the first electrode via the power supply wiring.

[0017] The structure can be configured as follows: a metal base supporting the electrostatic chuck plate from the back side opposite to the mounting surface, the current regulator being located on the side of the metal base opposite to the electrostatic chuck plate and inside the side cover.

[0018] Invention Effects

[0019] According to one aspect of the present invention, an electrostatic chuck device capable of plasma control around a focusing ring can be provided. Attached Figure Description

[0020] Figure 1 This 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.

[0021] Figure 2 This is a rough top view of the electrostatic chuck plate viewed from the rear side.

[0022] Figure 3 This is a diagram showing a constant current circuit that can be used with a current regulator.

[0023] Figure 4 This is a diagram showing a constant current circuit that can be used with a current regulator.

[0024] Figure 5 This is a diagram showing a constant current circuit that can be used with a current regulator. Detailed Implementation

[0025] Hereinafter, preferred embodiments of the electrostatic chuck device of the present invention will be described with reference to the accompanying drawings. Furthermore, in all the following drawings, the dimensions or ratios of the constituent components are sometimes shown differently to facilitate clear reading. Without departing from the spirit of the present invention, omissions, additions, changes, substitutions, replacements, or other modifications may be made to the quantity, position, size, or components.

[0026] Figure 1This is a schematic cross-sectional view of a plasma processing apparatus equipped with the electrostatic chuck device of this embodiment. Figure 2 This is a top view of the electrostatic chuck plate from the rear side.

[0027] The plasma processing apparatus 100 includes a vacuum container 101 and an electrostatic chuck device 1 fixed inside the vacuum container 101. The vacuum container 101 has a bottom wall 102, a cylindrical side wall 103 extending upward from the outer peripheral end of the bottom wall 102, and a top wall 104 fixed to the upper end of the side wall 103 and opposed to the bottom wall 102 in the vertical direction.

[0028] An electrostatic chuck device 1 is fixed to the bottom of the internal space of the vacuum container 101. The electrostatic chuck device 1 is fixed to the inner side of the bottom wall 102 (the upper surface shown in the figure). In this embodiment, the electrostatic chuck device 1 is arranged inside the vacuum container 101 with the mounting surface 2a of the wafer W facing upwards. The arrangement of the electrostatic chuck device 1 is an example, but other arrangements are also possible.

[0029] The bottom wall 102 of the vacuum container 101 has an opening 102a extending through the bottom wall 102 along its thickness direction and an exhaust port 102b. An electrostatic chuck device 1 closes the opening 102a from the inside (top side of the diagram) of the vacuum container 101. The exhaust port 102b is located to the side of the electrostatic chuck device 1. A vacuum pump (not shown) is connected to the exhaust port 102b.

[0030] The electrostatic chuck device 1 includes an electrostatic chuck plate 10 for adsorbing and supporting a wafer W and a metal base 11 for supporting the electrostatic chuck plate 10. A focusing ring 5 is arranged on the outer periphery of the upper surface of the electrostatic chuck plate 10, which surrounds the mounting surface 2a (wafer W) when viewed from above.

[0031] The electrostatic chuck plate 10 has a dielectric substrate 2 with a mounting surface 2a for mounting a wafer W and an adsorption electrode 6 located inside the dielectric substrate 2.

[0032] The dielectric substrate 2 is circular when viewed from above. The dielectric substrate 2 is composed of a composite sintered body that possesses mechanical strength and durability against corrosive gases and their plasmas. As the dielectric material constituting the dielectric substrate 2, ceramics that possess both mechanical strength and durability against corrosive gases and their plasmas are preferably used. For example, alumina (Al2O3) sintered bodies, aluminum nitride (AlN) sintered bodies, and alumina (Al2O3)-silicon carbide (SiC) composite sintered bodies are preferably used.

[0033] The upper surface of the dielectric substrate 2 is a mounting surface 2a on which the wafer W is mounted. Multiple protrusions (not shown) are formed on the mounting surface 2a at predetermined intervals. Each of the multiple protrusions has a diameter smaller than the thickness of the wafer W. The multiple protrusions on the mounting surface 2a support the wafer W. The shape of the protrusions can be arbitrarily chosen; for example, a cylindrical shape can be used.

[0034] The electrostatic chuck plate 10 has a ring-shaped adsorption region 2d radially outside the mounting surface 2a of the dielectric substrate 2. In this embodiment, the upper surface of the ring-shaped adsorption region 2d is located lower than the mounting surface 2a in the vertical direction shown in the figure. A focusing ring 5 is disposed on the ring-shaped adsorption region 2d. Figure 1 As shown, the outer periphery of the focusing ring 5 disposed in the ring adsorption region 2d protrudes further radially outward than the dielectric substrate 2. The outer periphery of the focusing ring 5, protruding outward from the dielectric substrate 2, is disposed within the notch 4b of the side cover 4, which will be described later. The height position (vertical position) of the upper surface of the focusing ring 5 is approximately the same as the height position of the upper surface of the wafer W placed on the mounting surface 2a.

[0035] The focusing ring 5 is formed of a material having the same conductivity as the wafer W placed on the mounting surface 2a. Specifically, silicon, silicon carbide, quartz, alumina, etc., can be used as the constituent materials of the focusing ring 5. By configuring the focusing ring 5, the electrical environment for plasma at the periphery of the wafer W can be made approximately the same as that of the wafer W. As a result, differences or inhomogeneities in plasma processing are less likely to occur between the center and the periphery of the wafer W.

[0036] The adsorption electrode 6 is located inside the dielectric substrate 2. The adsorption electrode 6 is composed of a first electrode 6a located in the region that overlaps with the mounting surface when viewed from above, and a second electrode 6b located in the region that overlaps with the focusing ring 5 when viewed from above. That is, the electrostatic chuck plate 10 has a first electrode 6a and a second electrode 6b.

[0037] like Figure 2 As shown, the first electrode 6a is circular when viewed from above. The first electrode 6a has a diameter slightly smaller than that of the mounting surface 2a and the wafer W. The first electrode 6a can be divided into multiple electrode portions. The multiple electrode portions can be arranged radially along the dielectric substrate 2, circumferentially, or both.

[0038] like Figure 2 As shown, the second electrode 6b is an annular shape extending along the outer periphery of the dielectric substrate 2. The second electrode 6b is composed of six electrode portions 61 to 66 arranged circumferentially along the dielectric substrate 2. The six electrode portions 61 to 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 disposed in the region overlapping with the annular adsorption region 2d, adsorbing the focusing ring 5.

[0039] The segmentation method of the second electrode 6b is not limited to Figure 2 The example shown. The second electrode 6b can be divided into multiple annular electrode portions. Alternatively, it can be further divided radially into six electrode portions 61 to 66.

[0040] like Figure 1 As shown, 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 focusing 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 adsorption region 2d is equivalent to the height difference between the thickness of the focusing ring 5 and the wafer W. By adjusting the height positions of the first electrode 6a and the second electrode 6b, the adsorption force between the first electrode 6a and the wafer W and the adsorption force between the second electrode 6b and the focusing ring 5 can be adjusted to appropriate ranges.

[0041] The dielectric substrate 2 is bonded to the upper surface of the metal base 11 on the back side 2b.

[0042] The metal base 11 is a circular plate-shaped metal component when viewed from above. The metal base 11 is made of, for example, aluminum alloy. The metal base 11 supports the electrostatic chuck plate 10 from the back side 2b. The metal base 11 is supported from below on a cylindrical support member 3 extending downward from the outer periphery of the back side of the metal base 11. Cylindrical side covers 4 are arranged radially outside the electrostatic chuck plate 10, the metal base 11, and the support member 3, surrounding them.

[0043] The metal base 11 has heating elements 9 distributed throughout its interior. The heating elements 9 and the metal base 11 are insulated from each other. A heater (not shown) is connected to the heating elements 9 by a power supply. The heating elements 9 can be located outside the metal base 11. The heating elements 9 can also be located inside the electrostatic chuck plate 10. The heating elements 9 can also be located between the electrostatic chuck plate 10 and the metal base 11.

[0044] The support member 3 is a cylindrical component extending from the outer periphery 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 positioned along the periphery of the opening 102a of the bottom wall 102. The support member 3 and the bottom wall 102 are hermetically sealed, for example, by an O-ring or similar material.

[0045] The space inside the support member 3 is connected to the space outside the vacuum container 101 via the opening 102a of the bottom wall 102. The back surface 2b of the dielectric substrate 2 is exposed in the space inside the support member 3. Operators can access the back surface 2b of the dielectric substrate 2 through the opening 102a of the bottom wall 102.

[0046] The side cover 4 is a cylindrical component extending vertically. The side cover 4 covers the outer side of the support member 3. In this embodiment, the side cover 4 is radially opposed to the side end face 2c of the dielectric substrate 2 and the outer peripheral surface 3b of the support member 3. The side cover 4 protects the side end face 2c of the dielectric substrate 2 and the outer peripheral surface 3b of the support member 3 from the effects of plasma. The side cover 4 is made of, for example, alumina or quartz. The material of the side cover 4 is not particularly limited as long as it is a material with the required plasma resistance. The electrostatic chuck device 1 may also be configured without the side cover 4.

[0047] The upper end portion 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 periphery at the corner of the inner peripheral side of the upper end portion 4a. The outer periphery of the focusing ring 5 is disposed inside the notch 4b. The height position (vertical position shown in the figure) of the upper end face 4c of the side cover 4 is approximately the same as the height position of the upper surface of the focusing ring 5 and the height position of the upper surface of the wafer W.

[0048] In the electrostatic chuck device 1, the electrostatic chuck plate 10 and the metal base 11 have a power connection hole 12a and a plurality of power connection holes 12b opening on the lower surface 11a of the metal base 11. The power connection hole 12a is located in the center of the metal base 11 when viewed from above. The power connection hole 12a extends upward from the lower surface 11a and reaches the lower surface of the first electrode 6a.

[0049] Multiple power connection holes 12b are provided at six locations corresponding to the six electrode portions 61 to 66. Each power connection hole 12b extends upward from the lower surface 11a of the metal base 11 and reaches the lower surface of the electrode portions 61 to 66. In this embodiment, the power connection holes 12b at the six locations are arranged at equal intervals in the circumferential direction of the electrostatic chuck plate 10.

[0050] Cylindrical insulating tubes (not shown) are embedded in power connection holes 12a and 12b. The insulating tubes are made of, for example, alumina. Power cables 151-157 (described later) of the power connection portion 50 are inserted into the inner side of the insulating tubes and connected to the first electrodes 6a and 6b at the bottom (top) of the power connection holes 12a and 12b. Power cables 151-157 are connected to the first electrode 6a and the second electrode 6b, for example, by soldering or brazing. Power cables 151-157 can be connected to the first electrode 6a and the second electrode 6b via connectors.

[0051] like Figure 1 As shown, the power supply device 110 includes a high-frequency power supply 111 for plasma excitation, a matching device 112, a DC power supply 113 for electrostatic adsorption, a resistor 114, a high-frequency power supply 115 for substrate biasing, and a matching device 116.

[0052] A high-frequency power supply 111 for plasma excitation is electrically connected via a matching adapter 112 to a main power supply rod 8 extending downward from the lower surface of the metal base 11. The main power supply rod 8 is, for example, a rod-shaped metal component made of aluminum, copper, stainless steel, etc. The upper end of the main power supply rod 8 is fixed to the lower 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 supply rod 8.

[0053] A DC power supply 113 for electrostatic adsorption is connected to power line 150 via resistor 114. A high-frequency power supply 115 for substrate biasing is connected to power line 150 via matching adapter 116.

[0054] like Figure 1 and Figure 2 As shown, the electrostatic chuck device 1 has a power connection section 50 that connects the power supply device 110 to the adsorption electrode 6. The power connection section 50 has eight power cables 150-157 and six current regulators 51-56. The power connection section 50 is connected to the power supply device 110 via the power cables 150. In this embodiment, the power cables 150 are electrically connected to the DC power supply 113 for electrostatic adsorption and the high-frequency power supply 115 for substrate biasing in the power supply device 110.

[0055] Power cable 150 is electrically connected to seven power cables 151-157 at node N. Additionally, in Figure 1 In the accompanying diagram, for ease of display, node N is divided into two parts. For example... Figure 2 As shown, six power cables 151-156 extend radially from node N toward the outer periphery of the electrostatic chuck plate 10. Figure 1 As shown, power cable 157 is inserted from node N into power connection hole 12a and connected to the first electrode 6a.

[0056] Six power cables 151-156 are inserted into different power connection holes 12b on the outer periphery of the electrostatic chuck plate 10. Power cable 151 is electrically connected to the electrode portion 61 of the second electrode 6b. Similarly, power cable 152 is electrically connected to electrode portion 62, power cable 153 to electrode portion 63, power cable 154 to electrode portion 64, power cable 155 to electrode portion 65, and power cable 156 to electrode portion 66, respectively.

[0057] Current regulator 51 is connected between node N of power supply line 151 and the second electrode 6b. Similarly, current regulators 52 to 56 are respectively connected between node N of power supply lines 152 to 156 and the second electrode 6b.

[0058] With the circuit structure described above, electrode portion 61 of the second electrode 6b is electrically connected to the first electrode 6a via power lines 151, 157 and current regulator 51. Similarly, electrode portion 62 is electrically connected to the first electrode 6a via power lines 152, 157 and current regulator 52. The other electrode portions 63 to 66 are also electrically connected to the first electrode 6a via power lines 153 to 157 and current regulators 53 to 56, respectively.

[0059] That is, the electrostatic chuck device 1 has power supply lines 151 to 157 that connect the first electrode 6a and the second electrode 6b via any one of the current regulators 51 to 56.

[0060] A power supply device 110 is connected at node N via power supply line 150. Therefore, power input from DC power supply 113 and high-frequency power supply 115 is supplied to the first electrode 6a via power supply lines 150 and 157. On the other hand, power controlled by current regulators 51 to 56 is supplied to the electrode portions 61 to 66 of the second electrode 6b via power supply lines 151 to 156.

[0061] In the electrostatic chuck device 1, the focusing ring 5 becomes thinner over time. As a result, the capacity between the metal substrate 11 and the plasma generation space increases relatively, and the high-frequency power input to the area where the focusing ring 5 is located increases. Consequently, the plasma distribution changes, the etching rate difference between the center and the periphery of the wafer W increases, or the wear rate of the focusing ring 5 increases.

[0062] Therefore, in the electrostatic chuck device 1 of this embodiment, the structure is as follows: the first electrode 6a located on the lower side of the wafer W and the second electrode 6b located on the lower side of the focusing ring 5 are connected via current regulators 51 to 56, and at node N located closer to the first electrode 6a than the current regulators 51 to 56, it is connected to the power supply device 110.

[0063] According to this structure, the current flowing from the power supply device 110 to the second electrode 6b can be adjusted using current regulators 51 to 56. Therefore, when the current flowing through the second electrode 6b increases due to the loss of the focusing ring 5, by suppressing the current using current regulators 51 to 56, excessive high-frequency power can be prevented from being input at the position of the focusing ring 5, and good plasma distribution can be maintained. According to the electrostatic chuck device 1 of this embodiment, plasma control around the focusing ring 5 can be performed.

[0064] Figures 3 to 5 This is a diagram showing a constant current circuit that can be applied to current regulators 51 to 56.

[0065] Figure 3The constant current circuit 200 shown is a circuit in which resistor 201 and PTC thermistor 202 are connected in parallel. In the constant current circuit 200, if the current flowing from the input terminal IN to the output terminal OUT increases, the PTC thermistor 202 heats up and becomes highly resistant, thus reducing the current flowing through the constant current circuit 200. The amount of current flowing through the constant current circuit 200 can be adjusted using the value of resistor 201.

[0066] By using the constant current circuit 200 as the current regulator 51-56, the current flowing through the power supply lines 151-156 can be controlled within a specified range, thus suppressing the uneven distribution of plasma around the focusing ring 5.

[0067] Figure 4 The constant current circuit 300 shown has a first transistor 301, a resistor 302, and a second transistor 303 connected sequentially from the input terminal IN side. Both the first transistor 301 and the second transistor 303 are N-channel depletion-type field-effect transistors.

[0068] The drain of transistor 301 is connected to the input terminal IN. The source of transistor 301 is connected to the IN side terminal of resistor 302 and the gate of transistor 303. The gate of transistor 301 is connected to the OUT side terminal of resistor 302 and the source of transistor 303. The drain of transistor 303 is connected to the output terminal OUT. The gate of transistor 303 is connected to the IN side terminal of resistor 302 and the source of transistor 301.

[0069] in addition, Figure 4 The two diodes shown are parasitic diodes of transistor 301 and transistor 303.

[0070] In the constant current circuit 300, the first transistor 301 is a depletion-type FET and a normally open switch. Current input from the input terminal IN flows from the drain to the source of the first transistor 301 and then to resistor 302. The voltage drop across resistor 302 is used as a bias voltage input to the gate of the first transistor 301. Consequently, the gate potential of the first transistor 301 becomes lower than its source potential, reducing the current flowing between the drain and source to a predetermined value. Additionally, the current input from resistor 302 to the source of the second transistor 303 is output to the output terminal OUT through the parasitic diode of the second transistor 303.

[0071] When current flows from the output terminal OUT to the input terminal IN in the constant current circuit 300, the second transistor 303 adjusts the current flowing in the constant current circuit 300. The current flowing from the resistor 302 to the first transistor 301 is output to the input terminal IN through the parasitic diode of the first transistor 301.

[0072] By using the constant current circuit 300 described above as the current regulators 51 to 56, the current flowing through the power supply lines 151 to 156 can be controlled within a specified range. In the structure using the constant current circuit 300, it is also possible to suppress uneven plasma distribution around the focusing ring 5.

[0073] Figure 5 The constant current circuit 400 shown has a first transistor 401, a resistor 402, and a second transistor 403 connected sequentially from the input terminal IN side. Furthermore, the constant current circuit 400 has a first photodiode 404 connected between the gate of the first transistor 401 and the OUT side terminal of the resistor 402, and a second photodiode 405 connected between the gate of the second transistor and the IN side terminal of the resistor 402.

[0074] Both transistor 401 (first transistor) and transistor 403 (second transistor) are N-channel enhancement-mode field-effect transistors.

[0075] 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 side terminal of the resistor 402 and the anode of the second photodiode 405. The gate of the first transistor is connected to the cathode of the first photodiode 404.

[0076] 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.

[0077] In addition, the first transistor 401 and the second transistor 403 each have parasitic diodes.

[0078] The constant current circuit 400 can control the current using a light source device 410 that illuminates the first photodiode 404 and the second photodiode 405. The light source device 410 includes 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. Light emitted from the light-emitting diode 411 is emitted to the first photodiode 404 and the second photodiode 405, for example, via an optical fiber.

[0079] In the constant current circuit 400, the first transistor 401 is an enhancement-mode FET and a normally off switch. When no light is irradiated from the light source device 410 to the first photodiode 404, no current flows through the first transistor 401.

[0080] If light is shone from the light source device 410 onto the first photodiode 404, the cathode potential of the first photodiode 404 is input to the gate of the first transistor 401, and the first transistor 401 becomes switched on. As a result, the current input from the input terminal IN flows from the drain of the first transistor 401 to the source, and then to the resistor 402.

[0081] The voltage drop across resistor 402 is used as a bias voltage input to the gate of transistor 401, causing the gate potential of transistor 401 to become lower than its source potential, thus reducing the current flowing between the drain and source to a specified value. The current input from resistor 402 to the source of transistor 403 is output to the output terminal OUT through the parasitic diode of transistor 403.

[0082] When current flows from the output terminal OUT to the input terminal IN in the constant current circuit 400, the current flowing in the constant current circuit 400 is adjusted by the second transistor 403 and the second photodiode 405. The current flowing from the resistor 402 to the first transistor 401 is output to the input terminal IN through the parasitic diode of the first transistor 401.

[0083] By using the constant current circuit 400 described above as the current regulators 51-56, the current flowing through the power supply lines 151-156 can be controlled within a specified range. In the structure using the constant current circuit 400, it is also possible to suppress uneven plasma distribution around the focusing ring 5. Furthermore, in the constant current circuit 400, the amount of light irradiating the first photodiode 404 and the second photodiode 405 from the light source device 410 can be used to control the amount of current flowing through the constant current circuit 400. By using the constant current circuit 400, the plasma around the focusing ring 5 can be controlled with higher precision.

[0084] Furthermore, in this embodiment, an example of a circuit applicable to current regulators 51-56 is shown. Figures 3 to 5 The constant current circuit shown is not limited to these structures. Components capable of automatically or manually adjusting the current flowing through power lines 151-156 can be used as current regulators 51-56. For example, a variable capacitor can also be used as the current regulator 51-56. By electrically or mechanically changing the electrostatic capacitance of the variable capacitor, the current flowing through power lines 151-156 can be adjusted, and the uniformity of the plasma on the wafer W and focusing ring 5 can be maintained.

[0085] In the electrostatic chuck device 1 of this embodiment, a side cover 4 surrounds the electrostatic chuck plate 10 from the radially outer side, and current adjusters 51 to 56 are located on the back side 2b 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.

[0086] According to this structure, since the current regulators 51 to 56 are housed within the internal space of the electrostatic chuck device 1, the electrostatic chuck device 1 can be made compact. Furthermore, since no components are disposed on the outside of the electrostatic chuck device 1, it can be configured as an electrostatic chuck device that is easily installed even in conventional plasma processing apparatuses.

[0087] In the electrostatic chuck device 1 of this embodiment, it is possible to... Figure 3 The constant current circuit 200 shown is used for the current regulators 51 to 56. That is, the electrostatic chuck device 1 can be configured to include a variable resistor in the current regulators 51 to 56.

[0088] Based on this structure, a current regulator can be constructed using a simple circuit. Since the current regulators 51 to 56 can be easily miniaturized, the power connection part 50 can be easily disposed on the back of the electrostatic chuck plate 10.

[0089] In the electrostatic chuck device 1 of this embodiment, it is possible to... Figures 3-5 The constant current circuits 200, 300, and 400 shown are used in current regulators 51 to 56. By using these constant current circuits 200, 300, and 400 in current regulators 51 to 56, the current regulators 51 to 56 operate in a way that suppresses current changes associated with the loss of the focusing ring 5. As a result, the plasma distribution state can be maintained over a long period of time.

[0090] In the electrostatic chuck device 1 of this embodiment, such as Figure 2 As shown, the second electrode 6b is divided into multiple electrode portions 61 to 66 arranged along the extension direction of the focusing ring 5, and each electrode portion 61 to 66 is connected to the first electrode 6a via power lines 151 to 156. According to this structure, since the multiple electrode portions 61 to 66 are arranged circumferentially along the electrostatic chuck plate 10 and the current of each electrode portion 61 to 66 can be controlled, plasma non-uniformity can also be suppressed in the circumferential direction.

[0091] In the electrostatic chuck device 1 of this embodiment, there is a metal base 11 that supports the electrostatic chuck plate 10 from the back side 2b side opposite to the mounting surface 2a. The current regulators 51 to 56 are located on the side of the metal base 11 opposite to the electrostatic chuck plate 10 and inside the side cover 4.

[0092] According to this structure, the current regulators 51 to 56 can be housed within the internal space of the electrostatic chuck device 1, thus enabling the miniaturization of the electrostatic chuck device 1. Since no components are arranged on the outside of the electrostatic chuck device 1, it is easy to install the electrostatic chuck device 1 on existing plasma processing devices.

[0093] Industrial availability

[0094] This invention provides an electrostatic chuck device capable of plasma control around a focusing ring. This invention also provides an electrostatic chuck that maintains a constant power balance between the substrate and the focusing ring.

[0095] Label Explanation

[0096] 1-Electrostatic chuck device

[0097] 2-Dielectric substrate

[0098] 2a-Placement surface

[0099] 2b - Back

[0100] 2c-side end face

[0101] 2d-ring adsorption region

[0102] 3-Supporting components

[0103] 3b-Outer Peripheral Surface

[0104] 4-Side Cover

[0105] 4a-Upper end

[0106] 4b - Notch

[0107] 4c - Upper end face

[0108] 5-Focusing Ring

[0109] 6-Adsorption electrode

[0110] 6a-Electrode 1

[0111] 6b - Second Electrode

[0112] 8-Main power supply rod

[0113] 9-Heating element

[0114] 10-Electrostatic chuck plate

[0115] 11-Metal abutment

[0116] 11a-Lower Surface

[0117] 12a - Power connection hole

[0118] 12b - Power connection hole

[0119] 50-Power Connection Section

[0120] 51, 52, 53, 54, 55, 56 - Current Regulators

[0121] 61, 62, 63, 64, 65, 66 - Electrode sections

[0122] 150, 151, 152, 153, 154, 155, 156, 157 - Power wiring

[0123] 200, 300, 400 - Constant Current Circuit

[0124] 201-Resistor

[0125] 202-PTC Thermistor (Variable Resistor)

[0126] 301 - Transistor 1

[0127] 302-Resistor

[0128] 303 - Second Transistor

[0129] 401 - Transistor 1

[0130] 402 Resistor

[0131] 403 - Second Transistor

[0132] 404-First Photodiode

[0133] 405 - Second photodiode

[0134] 410-Light Source Device

[0135] 411-Light Emitting Diode

[0136] 412-Control Device

[0137] N-node

[0138] W-chip

Claims

1. An electrostatic chuck device, comprising: An electrostatic chuck plate has a dielectric substrate and electrodes located inside the dielectric substrate, the dielectric substrate having a mounting surface for placing a wafer; A focusing ring is disposed on the outer periphery of the electrostatic chuck plate and surrounds the mounting surface; and The power connection section connects the electrodes to a power source, wherein... The electrostatic chuck plate has: a first electrode located in the region overlapping the mounting surface when viewed from above; and a second electrode located in the region overlapping the focusing ring when viewed from above. The power connection section includes a power wiring that 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 located on the input terminal side. The source of the first transistor is connected to the IN side terminal of the resistor and the gate of the second transistor. The gate of the first transistor is connected to the OUT side terminal of the resistor and the source of the second transistor. The drain of the second transistor is configured on the output side. The gate of the second transistor is connected to the IN side terminal of the resistor and the source of the first transistor.

2. The electrostatic chuck device according to claim 1, wherein it has a side cover that surrounds the electrostatic chuck plate radially outward. The current regulator is located on the back side of the dielectric substrate and inside the side cover.

3. The electrostatic chuck device according to claim 1 or 2, wherein, The second electrode is divided into multiple electrode portions arranged along the extension direction of the focusing ring. Each of the electrode portions is connected to the first electrode via the power supply wiring.

4. The electrostatic chuck device according to claim 1 or 2, having a metal base supporting the electrostatic chuck plate from a rear side opposite to the mounting surface, the current regulator being located on the side of the metal base opposite to the electrostatic chuck plate and inside the side cover.

5. The electrostatic chuck device according to claim 1, wherein, The first electrode is a circular electrode when viewed from above. The second electrode is a plurality of annular electrodes extending along the outer periphery of the dielectric substrate.

6. The electrostatic chuck device according to claim 1, wherein, The second electrodes have the same size and shape as each other.

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

8. The electrostatic chuck device according to claim 7, wherein, The constant current circuit can control the current using a light source device that illuminates the first photodiode and the second photodiode.

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