Electrostatic chuck

Abstract

To improve the uniformity of the temperature of a substrate held in an electrostatic chuck.SOLUTION: The electrostatic chuck includes: a dielectric member (a ceramic member 1111a) on which a substrate is placed; and an electrostatic electrode 1111b arranged in the dielectric member. The dielectric member includes: a first upper surface 200 having a gas exit part from which gas flows out; and an annular seal band 201 arranged outside the first upper surface, the annular seal band having a height larger than the height of the first upper surface. The seal band includes an outside peripheral part 240 and an inner peripheral part 241 having a height smaller than the height of the outer peripheral part. The electrostatic electrode is arranged immediately below the inner peripheral part of the seal band.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] Exemplary embodiments of the present disclosure relate to an electrostatic chuck. [Background technology]

[0002] Patent Document 1 describes a technique for providing an electrostatic chuck having an annular seal band that supports the outer periphery of a substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-15820 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides techniques that can improve the temperature uniformity of a substrate held by an electrostatic chuck. [Means for solving the problem]

[0005] An electrostatic chuck in one exemplary embodiment of the present disclosure includes a dielectric member on which a substrate is placed, and an electrostatic electrode disposed within the dielectric member, the dielectric member including a first upper surface having a gas outlet portion from which a gas flows out, and an annular seal band disposed outside the first upper surface and having a height higher than the first upper surface, the seal band including an outer periphery and an inner periphery having a height lower than the outer periphery, and the electrostatic electrode is disposed at least directly below the inner periphery of the seal band. Effect of the Invention

[0006] According to one exemplary embodiment of the present disclosure, a technique can be provided that can improve the temperature uniformity of a substrate held by an electrostatic chuck. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram for explaining a configuration example of a plasma processing system. [Diagram 2] FIG. 1 is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus. [Diagram 3] 1A and 1B are diagrams illustrating an example of the configuration of an electrostatic chuck according to an exemplary embodiment of the present invention. [Figure 4] FIG. 1 is a diagram showing an example of a ceramic configuration as viewed from above. [Diagram 5] 11A and 11B are diagrams showing an example of the configuration of a seal band with a peripheral portion of the seal band enlarged; [Figure 6] FIG. 11 is a diagram showing a configuration of a seal band as a comparative example. [Figure 7] FIG. 11 is a diagram showing a configuration of a seal band as a comparative example. [Figure 8] 11 is a table showing the relationship between the amount of bending of the substrate and the distance A. [Figure 9] 13A and 13B are diagrams showing an example of the configuration of a seal band whose inner periphery has a third upper surface and an inclined surface. [Figure 10] 13A and 13B are diagrams showing an example of the configuration of a seal band whose inner periphery has a third upper surface and an inclined surface. [Figure 11] 11A and 11B are diagrams showing an example of the configuration of a seal band in which the entire upper surface of the inner periphery is an inclined surface. [Figure 12] 1A to 1C are diagrams showing an example of the configuration of a seal band whose inner periphery has an inclined upper surface and a vertical surface. [Figure 13] 1A to 1C are diagrams showing an example of the configuration of a seal band whose inner periphery has an inclined upper surface and a vertical surface. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Each embodiment of the present disclosure will be described below.

[0009] In one exemplary embodiment, there is provided an electrostatic chuck for holding a substrate, the electrostatic chuck including: a dielectric member on which the substrate is placed; and an electrostatic electrode disposed within the dielectric member, the dielectric member including a first upper surface having a gas outlet portion through which gas flows out; and an annular seal band disposed outside the first upper surface and having a height higher than the first upper surface, the seal band including an outer periphery and an inner periphery having a height lower than the outer periphery, and the electrostatic electrode is disposed at least directly below the inner periphery of the seal band.

[0010] In one exemplary embodiment, the outer periphery of the sealing band has a flat second upper surface and the inner periphery of the sealing band has a flat third upper surface.

[0011] In one exemplary embodiment, the inner periphery of the seal band has an upper surface that further includes an inclined surface.

[0012] In one exemplary embodiment, the third top surface is lower than the second top surface and higher than the first top surface.

[0013] In one exemplary embodiment, the third top surface is at least 0.1 μm lower than the second top surface.

[0014] In one exemplary embodiment, the third top surface is at least 3 μm higher than the first top surface.

[0015] In one exemplary embodiment, the distance from the third upper surface to the electrostatic electrode is in the range of 100 μm to 750 μm.

[0016] In one exemplary embodiment, the inner periphery of the seal band has only a top surface that is the third top surface.

[0017] In one exemplary embodiment, the dielectric member further includes a plurality of protrusions disposed on the first upper surface and protruding upwardly relative to the first upper surface.

[0018] In one exemplary embodiment, the protrusion has a height equal to or less than the outer periphery of the seal band.

[0019] In one exemplary embodiment, the protrusions have a height in the range of 5 μm to 50 μm.

[0020] In one exemplary embodiment, the inner edge of the inner periphery of the seal band is located between the outer edge of the outermost protrusion and the inner edge of the outer periphery of the seal band.

[0021] In one exemplary embodiment, the inner end of the inner periphery of the seal band is located inside the radial midpoint between the outer end of the outermost protrusion and the inner end of the outer periphery of the seal band.

[0022] In one exemplary embodiment, the inner periphery of the sealing band has a height that is greater than or equal to half the height of the protrusion.

[0023] In one exemplary embodiment, the electrostatic electrode is positioned from just below the first upper surface to just below the seal band, and the outer end of the electrostatic electrode is located outboard of the radial center position of the inner circumference of the seal band.

[0024] In one exemplary embodiment, the electrostatic electrode has an outer edge that is located immediately below the outer periphery of the seal band.

[0025] In one exemplary embodiment, the outer periphery of the sealing band has a radial width in the range of 0.3 mm to 4 mm.

[0026] In one exemplary embodiment, the inner periphery of the seal band has a radial width in the range of 1 mm to 36 mm.

[0027] In one exemplary embodiment, the inner periphery of the sealing band has a radial width that is greater than the outer periphery of the sealing band.

[0028] In one exemplary embodiment, the entire upper surface of the inner periphery of the seal band is an inclined surface.

[0029] In one exemplary embodiment, the inner periphery of the seal band has an inclined upper surface and a vertical surface that are radially connected to one another.

[0030] In one exemplary embodiment, the dielectric member has a vertical thickness in the range of 0.5 mm to 5 mm.

[0031] Hereinafter, each embodiment of the present disclosure will be described in detail with reference to the drawings. In each drawing, the same or similar elements are given the same reference numerals, and duplicated explanations will be omitted. Unless otherwise specified, the positional relationship such as up, down, left, right, etc. will be described based on the positional relationship shown in the drawing. The dimensional ratio of the drawings does not indicate the actual ratio, and the actual ratio is not limited to the illustrated ratio.

[0032] <An example of a plasma processing device> FIG. 1 is a diagram for explaining a configuration example of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing device 1 and a control unit 2. The plasma processing system is an example of a substrate processing system, and the plasma processing device 1 is an example of a substrate processing device. The plasma processing device 1 includes a plasma processing chamber 10, a substrate support unit 11, and a plasma generation unit 12. The plasma processing chamber 10 has a plasma processing space. The plasma processing chamber 10 also has at least one gas supply port for supplying at least one processing gas to the plasma processing space, and at least one gas exhaust port for exhausting gas from the plasma processing space. The gas supply port is connected to a gas supply unit 20 described later, and the gas exhaust port is connected to an exhaust system 40 described later. The substrate support unit 11 is disposed in the plasma processing space, and has a substrate support surface for supporting a substrate.

[0033] The plasma generating unit 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma formed in the plasma processing space may be a capacitively coupled plasma (CCP), an inductively coupled plasma (ICP), an electron-cyclotron-resonance plasma (ECR plasma), a helicon wave plasma (HWP), a surface wave plasma (SWP), or the like. Also, various types of plasma generating units may be used, including an alternating current (AC) plasma generating unit and a direct current (DC) plasma generating unit. In one embodiment, the AC signal (AC power) used in the AC plasma generating unit has a frequency in the range of 100 kHz to 10 GHz. Thus, the AC signal includes a radio frequency (RF) signal and a microwave signal. In one embodiment, the RF signal has a frequency in the range of 100 kHz to 150 MHz.

[0034] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to execute various steps described in the present disclosure. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to execute various steps described herein. In one embodiment, a part or all of the control unit 2 may be included in the plasma processing apparatus 1. The control unit 2 may include, for example, a computer 2a. The computer 2a may include, for example, a processing unit (CPU: Central Processing Unit) 2a1, a storage unit 2a2, and a communication interface 2a3. The processing unit 2a1 may be configured to read a program from the storage unit 2a2 and execute the read program to perform various control operations. This program may be stored in the storage unit 2a2 in advance, or may be acquired via a medium when necessary. The acquired program is stored in the storage unit 2a2, and is read from the storage unit 2a2 by the processing unit 2a1 and executed. The medium may be various storage media readable by the computer 2a, or may be a communication line connected to the communication interface 2a3. The storage unit 2a2 may include a random access memory (RAM), a read only memory (ROM), a hard disk drive (HDD), a solid state drive (SSD), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication line such as a local area network (LAN).

[0035] The following describes a configuration example of a capacitively coupled plasma processing apparatus as an example of the plasma processing apparatus 1. Fig. 2 is a diagram for explaining the configuration example of a capacitively coupled plasma processing apparatus.

[0036] The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply 20, a power supply 30, and an exhaust system 40. The plasma processing apparatus 1 also includes a substrate support 11 and a gas inlet. The gas inlet is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas inlet includes a showerhead 13. The substrate support 11 is disposed in the plasma processing chamber 10. The showerhead 13 is disposed above the substrate support 11. In one embodiment, the showerhead 13 forms at least a part of a ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the showerhead 13, a sidewall 10a of the plasma processing chamber 10, and the substrate support 11. The plasma processing chamber 10 is grounded. The showerhead 13 and the substrate support 11 are electrically insulated from a plasma processing chamber 10 housing.

[0037] The substrate support 11 includes a main body 111 and a ring assembly 112. The main body 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 111 surrounds the central region 111a of the main body 111 in a plan view. The substrate W is disposed on the central region 111a of the main body 111, and the ring assembly 112 is disposed on the annular region 111b of the main body 111 so as to surround the substrate W on the central region 111a of the main body 111. Therefore, the central region 111a is also called a substrate support surface for supporting the substrate W, and the annular region 111b is also called a ring support surface for supporting the ring assembly 112.

[0038] 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 may 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 is an example of a dielectric member. 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, an RF or DC electrode may be disposed in the ceramic member 1111a, in which case the RF or DC electrode functions as the lower electrode. When a bias RF signal or DC signal, which will be described later, is connected to the RF or DC electrode, the RF or DC electrode is also called a bias electrode. Note that both the conductive member of the base 1110 and the RF or DC electrode may function as two lower electrodes.

[0039] 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 rings are formed of a conductive or insulating material, and the cover rings are formed of an insulating material.

[0040] The substrate support 11 may also include a temperature adjustment 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 adjustment module may include a heater, a heat transfer medium, a flow path 1110a, or a combination thereof. A flow path 1110a is formed in the substrate support 11, and a heat transfer fluid such as brine or gas may flow through the flow path 1110a. The flow path 1110a may be provided in the electrostatic chuck 1111 or the base 1110. A coolant supply device 1110b may be connected to the flow path 1110a. The coolant whose temperature is set by the coolant supply device 1110b may flow and circulate through the flow path 1110a, thereby cooling the electrostatic chuck 1111 and the substrate W held by the electrostatic chuck 1111. In one embodiment, the flow passage 1110a is formed in the base 1110, and one or more heaters are disposed in the ceramic member 1111a of the electrostatic chuck 1111. The substrate support 11 may also include a heat transfer gas supply configured to supply a heat transfer gas between the backside of the substrate W and the central region 111a.

[0041] The shower head 13 is configured to introduce at least one processing gas from the gas supply unit 20 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 multiple gas inlets 13c. The processing 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 multiple gas inlets 13c. The shower head 13 also includes an upper electrode. Note that the gas introduction unit may include, in addition to the shower head 13, one or more side gas injectors (SGIs) attached to one or more openings formed in the sidewall 10a.

[0042] The gas supply 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply 20 is configured to supply at least one process gas from a respective gas source 21 through a respective flow controller 22 to the showerhead 13. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas supply 20 may include at least one flow modulation device to modulate or pulse a flow rate of the at least one process gas.

[0043] The power source 30 includes an RF power source 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power source 31 is configured to supply at least one RF signal (RF power), such as a source RF signal and a bias RF signal, to at least one lower electrode and / or at least one upper electrode. This causes a plasma to be formed from at least one processing gas supplied to the plasma processing space 10s. Thus, the RF power source 31 can function as at least a part of the plasma generating unit 12. In addition, by supplying a bias RF signal to the at least one lower electrode, a bias potential is generated on the substrate W, and ion components in the formed plasma can be attracted to the substrate W.

[0044] In one embodiment, the RF power supply 31 includes a first RF generating unit 31a and a second RF generating unit 31b. The first RF generating 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 generating unit 31a may be configured to generate a plurality of source RF signals having different frequencies. The generated one or more source RF signals are supplied to at least one lower electrode and / or at least one upper electrode.

[0045] The second RF generating unit 31b is coupled to at least one lower electrode via at least one impedance matching circuit and 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 generating unit 31b may be configured to generate a plurality of bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to at least one lower electrode. Also, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0046] 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 generator 32a and a second DC generator 32b. In one embodiment, the first DC generator 32a is connected to at least one lower electrode and configured to generate a first DC signal. The generated first DC signal is applied to the at least one lower electrode. In one embodiment, the second DC generator 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 the at least one upper electrode.

[0047] In various embodiments, the first and second DC signals may be pulsed. In this case, a sequence of DC-based 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 of these pulse waveforms. In one embodiment, a waveform generator for generating a sequence of voltage pulses from the DC signal is connected between the first DC generator 32a and at least one lower electrode. Thus, the first DC generator 32a and the waveform generator constitute a voltage pulse generator. When the second DC generator 32b and the waveform generator constitute a voltage pulse generator, the voltage pulse generator is connected to at least one upper electrode. The voltage pulses may have a positive polarity or a negative polarity. Also, the sequence of voltage pulses may include one or more positive polarity voltage pulses and one or more negative polarity voltage pulses within one period. The first and second DC generating units 32a, 32b may be provided in addition to the RF power supply 31, or the first DC generating unit 32a may be provided in place of the second RF generating unit 31b.

[0048] The exhaust system 40 may be connected to, for example, a gas exhaust port 10e provided 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 in the plasma processing space 10s is adjusted by the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0049] <Example of electrostatic chuck configuration> 3 is a diagram showing an example of the configuration of the electrostatic chuck 1111 in this exemplary embodiment. In one embodiment, the electrostatic chuck 1111 has a ceramic member 1111a as a dielectric member and an electrostatic electrode 1111b.

[0050] In one embodiment, the ceramic member 1111a includes a first upper surface 200 and a seal band 201 that is an annular protrusion disposed on the outer side of the first upper surface 200. The seal band 201 has a height higher than the first upper surface 200. The seal band 201 may be formed integrally with other portions of the ceramic member 1111a, including the first upper surface 200, or may be formed separately.

[0051] 4 is a diagram showing an example of the configuration of the ceramic member 1111a as viewed from above. In one embodiment, the first upper surface 200 has a circular shape with its center at the center of the ceramic member 1111a. The seal band 201 has an annular shape with its center at the center of the ceramic member 1111a. By providing such an annular seal band 201, the electrostatically attracted substrate W comes into contact with the upper surface of the seal band 201, preventing the heat transfer gas from leaking out from the space between the back surface of the substrate W and the electrostatic chuck 1111 into the plasma processing space 10s.

[0052] 3, the first upper surface 200 has a gas outlet 210 through which the heat transfer gas flows out. In an embodiment, the gas outlet 210 is connected to a heat transfer gas supply unit 212 through a gas passage 211. The gas passage 211 may pass through the inside of the substrate support 11. The heat transfer gas supply unit 212 may be provided outside the chamber 10. One or more gas outlets 210 may be arranged. The heat transfer gas may include helium gas.

[0053] In one embodiment, a plurality of columnar protrusions 220 are arranged on the first upper surface 200. In one embodiment, the protrusions 220 protrude upward from the first upper surface 200. In one embodiment, the protrusions 220 have a cylindrical shape. In one embodiment, as shown in FIG. 4, the plurality of protrusions 220 may be arranged at equal intervals along the circumferential direction around the center of the first upper surface 200. The plurality of protrusions 220 may be arranged concentrically or radially with respect to the center of the first upper surface 200.

[0054] 3, the seal band 201 includes an annular outer circumferential portion 240 and an annular inner circumferential portion 241 having a height lower than that of the outer circumferential portion 240. The outer circumferential portion 240 is located outside the inner circumferential portion 241 in the radial direction X. FIG. 5 is a diagram showing an example of the configuration of the seal band 201 with a peripheral portion of the seal band 201 enlarged.

[0055] In one embodiment, the outer periphery 240 has a flat second upper surface 250. In one embodiment, the outer periphery 240 has a chamfer 251 at the outermost periphery of the upper surface.

[0056] In one embodiment, the inner circumferential portion 241 has only a flat third upper surface 260. That is, no protrusions or recesses are provided on the upper surface of the inner circumferential portion 241. However, as described below, a protrusion may be provided on the upper surface of the inner circumferential portion 241.

[0057] The third upper surface 260 may be lower than the second upper surface 250 and higher than the first upper surface 200. That is, the first upper surface 200, the third upper surface 260, and the second upper surface 250 may be formed in a stepped shape that increases in height in this order toward the outside in the radial direction X. The second upper surface 250 is configured so that the substrate W does not come into contact with the second upper surface 250 even if the substrate W is warped, in order to ensure a gap that allows the heat transfer gas to enter the space between the substrate W and the inner circumferential portion 241. For this reason, the third upper surface 260 is preferably lower than the second upper surface 250 by 0.1 μm or more.

[0058] The third upper surface 260 is higher than the first upper surface 200. This reduces the distance between the substrate W and the third upper surface 260, and the electrostatic attraction to the substrate W can be increased at the inner periphery 241. As a result, the electrostatic attraction to the substrate W in the seal band 201 can be secured. The third upper surface 260 is preferably 3 μm or more higher than the first upper surface 200. In addition, the difference in height ΔH between the third upper surface 260 and the second upper surface 250 (or the upper surface of the convex portion 220) is preferably 7 μm or less. The third upper surface 260 may have a height H2 that is half or more of the height H1 of the convex portion 220 based on the first upper surface 200. The vertical distance L1 from the third upper surface 260 to the electrostatic electrode 1111b may be within a range of 100 μm to 750 μm.

[0059] A columnar or annular protrusion may be provided on the third upper surface 260. By providing a protrusion closer to the substrate W than the third upper surface 260, the electrostatic attraction to the substrate W can be increased in the inner peripheral portion 241. However, if a protrusion is provided on the third upper surface 260, the contact pressure between the substrate W and the outer peripheral portion 240 may be weakened due to contact between the upper surface of the protrusion and the substrate W, and the heat transfer gas may leak. Therefore, it is preferable not to provide a protrusion on the third upper surface 260, or, even if a protrusion is provided, to make the upper surface of the protrusion lower than the second upper surface 250. In addition, from the viewpoint of increasing the electrostatic attraction, it is preferable to form the protrusion in an annular shape. However, if the protrusion is formed in an annular shape, the space between the protrusion and the outer peripheral portion 240 may be blocked by the bending of the substrate, and the heat transfer gas may not be able to enter the space. Therefore, if a protrusion is formed, it is preferable to form it in a columnar shape.

[0060] The inner circumferential portion 241 is provided between the outermost convex portion 220 and the outer circumferential portion 240. That is, the inner end portion 241a of the inner circumferential portion 241 is located between the outer end portion 220a of the outermost convex portion 220 and the inner end portion 240a of the outer circumferential portion 240. In order to ensure a sufficient electrostatic attraction, it is desirable that the area of ​​the inner circumferential portion 241 is large. For this reason, it is preferable that the inner end portion 241a of the inner circumferential portion 241 is located inside the midpoint P1 in the radial direction X between the outer end portion 220a of the outermost convex portion 220 and the inner end portion 240a of the outer circumferential portion 240. The inner circumferential portion 241 may be formed up to the outer end portion 220a of the outermost convex portion 220. In addition, it is preferable that the width D2 in the radial direction X of the inner circumferential portion 241 is larger than the width D1 in the radial direction X of the outer circumferential portion 240.

[0061] However, if the area of ​​the inner peripheral portion 241 is too large, the substrate W will bend and come into contact with the third upper surface 260. FIG. 8 is a table showing the relationship between the distance A (shown in FIG. 5) between the outermost convex portion 220 and the inner end portion 240a of the outer peripheral portion 240 and the amount of bending of the substrate W. The inner peripheral portion 241 can be extended inward up to the position of the outermost convex portion 220, but if the width D2 in the radial direction X of the inner peripheral portion 241 is set to 36 mm or less, the amount of bending of the substrate W will be approximately 7 μm or less. Therefore, the width D2 in the radial direction X of the inner peripheral portion 241 is preferably set to a range of 1 mm to 36 mm.

[0062] The protrusion 220 may have a height H1 that is equal to or lower than the outer periphery 240. The height H1 of the protrusion 220 may be within a range of 5 μm to 50 μm.

[0063] The width D1 of the outer periphery 240 in the radial direction X may be within a range of 0.3 mm to 4 mm.

[0064] 3, the electrostatic electrode 1111b may be disposed directly below the first upper surface 200 and the seal band 201 within the ceramic member 1111a. In one embodiment, the electrostatic electrode 1111b has a circular shape. In one embodiment, the electrostatic electrode 1111b is connected to a direct current (DC) power supply 301 via a switch 300. When a DC voltage from the DC power supply 301 is applied to the electrostatic electrode 1111b, an electrostatic attractive force (Coulomb force) is generated between the ceramic member 1111a and the substrate W. The substrate W is attracted to the ceramic member 1111a by the electrostatic attractive force and is adsorbed and held on the upper surface of the ceramic member 1111a.

[0065] 5 , the electrostatic electrode 1111b is disposed from immediately below the first upper surface 200 to immediately below the seal band 201. The electrostatic electrode 1111b may be disposed at least immediately below the inner circumferential portion 241. An outer end 1111b-1 of the electrostatic electrode 1111b may be located outside a center position P2 in the radial direction X of the inner circumferential portion 241. The outer end 1111b-1 may be located immediately below the outer circumferential portion 240.

[0066] As shown in FIG. 3, the thickness L2 of the ceramic member 1111a in the vertical direction may be within a range of 0.5 mm to 5 mm.

[0067] <An example of a plasma processing method> The plasma processing method includes an etching process in which plasma is used to etch a film on a substrate W. In one embodiment, the plasma processing method is performed by a control unit 2 in a plasma processing apparatus 1.

[0068] First, as shown in Fig. 2, the substrate W is carried into the chamber 10 and placed on the substrate support 11. The substrate W is attracted and held by the electrostatic chuck 1111 as shown in Fig. 3. At this time, the substrate W is placed on the ceramic member 1111a and comes into contact with the outer circumferential portion 240 of the seal band 201. A DC voltage is applied to the electrostatic electrode 1111b, generating an electrostatic attractive force between the seal band 201 and the substrate W, and the substrate W is attracted to the seal band 201.

[0069] In the substrate support part 11 shown in FIG. 2, a coolant is supplied from a coolant supply device 1110b to a flow path 1110a, and the electrostatic chuck 1111 and the substrate W held by the electrostatic chuck 1111 are regulated to a predetermined temperature.

[0070] The heat transfer gas is supplied from the heat transfer gas supply unit 212 to the gas outlet unit 210, and the heat transfer gas is supplied from the gas outlet unit 210 to the space formed between the substrate W and the first upper surface 200. The heat transfer gas is also supplied to the space formed between the substrate W and the third upper surface 260. The seal band 201 seals the space between the first upper surface 200 and the substrate W so that the heat transfer gas filled therein does not leak into the plasma processing space 10s. The heat transfer gas adjusts the temperature of the substrate W from its back surface side.

[0071] 2 to the shower head 13, and then to the plasma processing space 10s from the shower head 13. The processing gas supplied at this time contains a gas that generates active species required for etching the substrate W.

[0072] One or more RF signals are supplied from an RF power supply 31 to the upper electrode and / or the lower electrode. The atmosphere in the plasma processing space 10s may be exhausted from a gas exhaust port 10e, and the inside of the plasma processing space 10s may be depressurized. As a result, plasma is generated on the substrate support 11 in the plasma processing space 10s, and the substrate W is etched. During the plasma processing, the substrate W is cooled by a heat transfer gas supplied to the rear surface of the substrate W from a gas outlet 210 shown in FIG. 3 and an outer circumferential portion 240 of the seal band 201 whose temperature is adjusted by a refrigerant.

[0073] According to this exemplary embodiment, the ceramic member 1111a of the electrostatic chuck 1111 includes a first upper surface 200 and an annular seal band 201, the seal band 201 includes an outer periphery 240 and an inner periphery 241 having a height lower than that of the outer periphery 240, and the electrostatic electrode 1111b is disposed at least directly below the inner periphery 241. As a result, a gap is formed between the inner periphery 241 of the seal band 201 and the substrate W, the heat transfer gas reaches the gap above the inner periphery 241, and the temperature control of the substrate W by the heat transfer gas is performed up to the outer periphery of the substrate W. In addition, since the inner periphery 241 of the seal band 201 is closer to the substrate W than the first upper surface 200, the electrostatic attraction force to the substrate W is larger in the inner periphery 241 of the seal band 201 than in the central portion (the portion having the first upper surface 200). Therefore, the contact pressure (adsorption force per unit area) between the substrate W and the outer periphery 240 increases, and the substrate W is adsorbed to the outer periphery 240 with a strong force. As a result, minute gaps that may occur between the substrate W and the outer periphery 240 due to surface roughness or the like are reduced, the contact area between the substrate W and the outer periphery 240 is increased, and heat is efficiently transferred between the electrostatic chuck 1111 and the outer periphery of the substrate W. As a result of the above, in the plasma processing, the outer periphery of the substrate W can be sufficiently cooled, and the temperature uniformity of the substrate held by the electrostatic chuck 1111 can be improved.

[0074] <Example> (1) As an example, the seal band 201 has an inner periphery 241 lower than the outer periphery 240 as in this exemplary embodiment; (2) As a comparative example, the seal band 201 has an inner periphery 500 having the same height as the outer periphery 240 as shown in FIG. 6; and (3) As a comparative example, the seal band 201 has an inner periphery 501 having the same height as the first upper surface 200 as shown in FIG. 7. The contact pressure of the seal band 201 against the substrate was compared. The width of the outer periphery 240 in the radial direction X is 1.7 mm, and the width of the inner periphery 241 (500, 501) in the radial direction X is 1.8 mm. In (1), the difference in height ΔH between the third upper surface 260 and the second upper surface 250 is 5 μm. In the case of (2), the radial width of the outer periphery 240 of the seal band 20 is substantially larger than in the case of (1), and the contact area between the substrate W and the seal band 201 is larger. In the case of (3), the contact area between the substrate W and the seal band 201 is the same as in the case of (1), but the distance between the inner periphery 501 and the substrate W is greater than in the case of (1). When the same voltage was applied to the electrostatic electrode 1111b in the cases of (1) to (3), the contact pressure in the case of (1) was 17.7 kPa, the contact pressure in the case of (2) was 14.3 kPa, and the contact pressure in the case of (3) was 16.0 kPa. As a result, it was confirmed that in the case of (1), heat was transferred between the substrate W and the seal band 201 more than in the cases of (2) and (3). In fact, when the substrate W was held by the electrostatic chuck 1111 and the temperature of the outer periphery of the substrate W was measured when the substrate W was cooled by the electrostatic chuck 1111, a lower temperature effect of about 1.5°C to 2.2°C was obtained in the case of (1) compared to the cases of (2) and (3).

[0075] In the above embodiment, the upper surface of the inner peripheral portion 241 of the seal band 201 has only the third upper surface 260, but may further have an inclined surface. In one embodiment, as shown in FIG. 9, the upper surface of the inner peripheral portion 241 of the seal band 201 has the third upper surface 260 and an inclined surface 310. The inclined surface 310 and the third upper surface 260 may be connected to each other. The inclined surface 310 may be configured such that one end is connected to the first upper surface 200 and the other end is connected to the third upper surface 260. In one embodiment, as shown in FIG. 10, the inclined surface 310 may be configured such that one end is connected to the second upper surface 250 and the other end is connected to the third upper surface 260.

[0076] In one embodiment, as shown in FIG. 11, the entire upper surface of the inner circumferential portion 241 of the seal band 201 may be an inclined surface 310 .

[0077] 12 , the inner periphery 241 of the seal band 201 may have an inclined upper surface 320 and a vertical surface 321 that are connected to each other in the radial direction X. The inclined upper surface 320 may be configured to have one end connected to the first upper surface 200 and the other end connected to the vertical surface 321. The vertical surface 321 may be configured to have one end connected to the inclined upper surface 320 and the other end connected to the second upper surface 250.

[0078] 13, vertical surface 321 may be configured to have one end connected to first top surface 200 and the other end connected to angled top surface 320. Inclined top surface 320 may be configured to have one end connected to vertical surface 321 and the other end connected to second top surface 250.

[0079] By having such an inclined surface, the electrostatic attraction force on the substrate W can be made larger than when there is only a flat third upper surface 260 as shown in Figure 5, and the substrate W can be adsorbed to the outer periphery 240 with a strong force.

[0080] In the above embodiment, the electrostatic chuck 1111 is used in a capacitively coupled plasma device, but the present invention is not limited to this and may be used in other types of plasma devices. Moreover, the electrostatic chuck 1111 is not limited to a plasma processing device and may be used in other substrate processing devices.

[0081] The embodiments of the present disclosure further include the following aspects.

[0082] (Appendix 1) An electrostatic chuck for holding a substrate, comprising: a dielectric member on which the substrate is placed; an electrostatic electrode disposed within the dielectric member; The dielectric member is a first upper surface having a gas outlet portion through which gas flows out; an annular seal band disposed outside the first upper surface and having a height higher than the first upper surface; The seal band is The outer periphery and an inner periphery having a height less than that of the outer periphery; The electrostatic electrode is disposed at least directly below the inner circumferential portion of the seal band. Electrostatic chuck.

[0083] (Appendix 2) The outer periphery of the seal band has a flat second upper surface, The inner periphery of the seal band has a flat third upper surface. 2. The electrostatic chuck of claim 1.

[0084] (Appendix 3) The upper surface of the inner peripheral portion of the seal band further has an inclined surface. 3. The electrostatic chuck of claim 2.

[0085] (Appendix 4) The third upper surface is lower than the second upper surface and higher than the first upper surface. 4. The electrostatic chuck of claim 2 or 3.

[0086] (Appendix 5) The third upper surface is lower than the second upper surface by 0.1 μm or more. 5. The electrostatic chuck of claim 2.

[0087] (Appendix 6) The third upper surface is higher than the first upper surface by 3 μm or more. 6. The electrostatic chuck of claim 2.

[0088] (Appendix 7) The distance from the third upper surface to the electrostatic electrode is within a range of 100 μm to 750 μm. 7. The electrostatic chuck of claim 2.

[0089] (Appendix 8) The upper surface of the inner peripheral portion of the seal band has only the third upper surface. 8. The electrostatic chuck of claim 2.

[0090] (Appendix 9) The dielectric member is disposed on the first upper surface and further has a plurality of protrusions protruding upward from the first upper surface. 9. The electrostatic chuck of claim 1.

[0091] (Appendix 10) The protrusion has a height equal to or lower than the outer circumferential portion of the seal band. 10. The electrostatic chuck of claim 9.

[0092] (Appendix 11) The protrusions have a height in the range of 5 μm to 50 μm. 11. The electrostatic chuck of claim 9 or 10.

[0093] (Appendix 12) an inner end portion of the inner peripheral portion of the seal band is located between an outer end portion of the outermost protrusion and an inner end portion of the outer peripheral portion of the seal band; 12. The electrostatic chuck of claim 9.

[0094] (Appendix 13) an inner end portion of the inner peripheral portion of the seal band is located inside a midpoint in a radial direction between an outer end portion of the outermost convex portion and an inner end portion of the outer peripheral portion of the seal band; 13. The electrostatic chuck of claim 9.

[0095] (Appendix 14) The inner peripheral portion of the seal band has a height equal to or greater than half the height of the protruding portion. 14. The electrostatic chuck of claim 9.

[0096] (Appendix 15) the electrostatic electrode is disposed from directly below the first upper surface to directly below the seal band, an outer end portion of the electrostatic electrode is located outward from a radial center position of the inner circumferential portion of the seal band; 15. The electrostatic chuck of claim 1.

[0097] (Appendix 16) The outer end of the electrostatic electrode is located directly below the outer periphery of the seal band. 16. The electrostatic chuck of claim 15.

[0098] (Appendix 17) The radial width of the outer circumferential portion of the seal band is within a range of 0.3 mm to 4 mm. 17. The electrostatic chuck of any one of claims 1 to 16.

[0099] (Appendix 18) The radial width of the inner circumferential portion of the seal band is within a range of 1 mm to 36 mm. 18. The electrostatic chuck of any one of claims 1 to 17.

[0100] (Appendix 19) The radial width of the inner circumferential portion of the seal band is larger than the radial width of the outer circumferential portion of the seal band. 19. The electrostatic chuck of any one of claims 1 to 18.

[0101] (Appendix 20) The entire upper surface of the inner peripheral portion of the seal band is an inclined surface. 20. The electrostatic chuck of claim 1.

[0102] (Appendix 21) The inner periphery of the seal band has an inclined upper surface and a vertical surface connected to each other in a radial direction. 21. The electrostatic chuck of any one of claims 1 to 20.

[0103] (Appendix 22) The thickness of the dielectric member in the vertical direction is within a range of 0.5 mm to 5 mm. 22. The electrostatic chuck of any one of claims 1 to 21.

[0104] The above embodiments are described for the purpose of explanation and are not intended to limit the scope of the present disclosure. Various modifications can be made to the above embodiments without departing from the scope and spirit of the present disclosure. For example, some components in one embodiment can be added to other embodiments. Also, some components in one embodiment can be replaced with corresponding components in other embodiments. [Explanation of symbols]

[0105] 1: plasma processing apparatus, 10: chamber, 11: substrate support, 112: ring assembly, 1111: electrostatic chuck, 1111a: ceramic member, 1111b: electrostatic electrode, 200: first upper surface, 201: seal band, 240: outer periphery, 241: inner periphery, 250: second upper surface, 260: third upper surface, W: substrate

Claims

1. An electrostatic chuck for holding a substrate, A dielectric material on which the substrate is placed, The dielectric member includes an electrostatic electrode disposed within the dielectric member, The dielectric member is A first upper surface having a gas outlet from which gas flows out, An annular seal band positioned outside the first upper surface and having a height higher than the first upper surface, It includes a plurality of protrusions arranged on the first upper surface and projecting upward relative to the first upper surface, The aforementioned sealing band is An outer periphery having a second upper surface, It includes an inner circumferential portion having a third upper surface provided at a lower height than the second upper surface, The third upper surface is 3 μm or more higher than the first upper surface, and the height difference between it and the second upper surface is 7 μm or less. The electrostatic electrode is positioned at least directly below the inner circumference of the seal band. Electrostatic chuck.

2. The electrostatic chuck according to claim 1, wherein the distance between the outer end of the outermost of the plurality of protrusions and the inner end of the outer circumference of the seal band is 36 mm or less.

3. The electrostatic chuck according to claim 1, wherein the height difference between the third upper surface and the second upper surface is greater than 5 μm, and the distance between the outer end of the outermost of the plurality of protrusions and the inner end of the outer circumference of the seal band is within 32.7 mm.

4. The electrostatic chuck according to claim 1, wherein the height difference between the third upper surface and the second upper surface is greater than 1 μm, and the distance between the outer end of the outermost of the plurality of protrusions and the inner end of the outer circumference of the seal band is within 21.8 mm.

5. The distance from the third upper surface to the electrostatic electrode is within the range of 100 μm to 750 μm. The electrostatic chuck according to claim 1.

6. The upper surface of the inner circumference of the seal band has only the third upper surface. The electrostatic chuck according to claim 1.

7. The aforementioned protrusion has a height equal to or lower than the outer circumference of the seal band. The electrostatic chuck according to claim 1.

8. The aforementioned protrusion has a height in the range of 5 μm to 50 μm. The electrostatic chuck according to claim 7.

9. The inner circumference of the seal band has a height of at least half the height of the protrusion. The electrostatic chuck according to claim 1.

10. The outer end of the electrostatic electrode is located directly below the outer circumference of the seal band. The electrostatic chuck according to claim 1.

11. The radial width of the outer circumference of the seal band is in the range of 0.3 mm to 4 mm. The electrostatic chuck according to claim 1.

12. The thickness of the dielectric member in the vertical direction is in the range of 0.5 mm to 5 mm. The electrostatic chuck according to claim 1.

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