Electrostatic chuck

Abstract

The present invention provides a technique capable of improving temperature uniformity of a substrate held by an electrostatic chuck. The electrostatic chuck includes: a dielectric member on which the substrate is placed; and an electrostatic electrode disposed within the dielectric member. The dielectric member includes: a first upper surface having a gas outflow portion from which gas flows out; and a ring-shaped sealing tape disposed on the outside of the first upper surface and having a height higher than that of the first upper surface. The sealing tape includes: an outer peripheral portion; and an inner peripheral portion having a lower height than the outer peripheral portion. The electrostatic electrode is disposed at least directly below the inner peripheral portion of the sealing tape.

Description

[0001] This application is a divisional application of the patent application filed on March 11, 2024, with application number 202480003749.3 and invention title "Electrostatic Chuck". Technical Field

[0002] The exemplary embodiments of the present invention relate to electrostatic chucks. Background Technology

[0003] As a technology for providing an electrostatic chuck with an annular sealing strip that supports the outer periphery of a substrate, there is a technology described in Patent Document 1.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent document 1: Japanese Patent Application Publication No. 2021-15820. Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] This invention provides a technique that can improve the temperature uniformity of a substrate held by an electrostatic chuck.

[0009] Technical means for solving problems

[0010] An exemplary embodiment of the electrostatic chuck of the present invention includes: a dielectric component for mounting a substrate; and an electrostatic electrode disposed within the dielectric component. The dielectric component includes: a first upper surface having a gas outflow portion for gas outflow; and an annular sealing strip disposed outside the first upper surface, having a height higher than the first upper surface. The sealing strip includes: an outer peripheral portion; and an inner peripheral portion having a height lower than the outer peripheral portion. The electrostatic electrode is disposed at least directly below the inner peripheral portion of the sealing strip.

[0011] The effects of the invention

[0012] According to an exemplary embodiment of the present invention, a technique is provided that can improve the temperature uniformity of a substrate held by an electrostatic chuck. Attached Figure Description

[0013] Figure 1 This is a diagram illustrating a structural example of a plasma processing system.

[0014] Figure 2 This is a diagram illustrating a structural example of a capacitively coupled plasma processing device.

[0015] Figure 3 This is a diagram illustrating an example of the structure of the electrostatic chuck in the embodiment shown in this example.

[0016] Figure 4 This is a diagram showing an example of the structure of a ceramic when viewed from above.

[0017] Figure 5 This is a diagram showing an example of the structure of a sealing strip when the peripheral portion of the sealing strip is enlarged.

[0018] Figure 6 This is a diagram showing the structure of the sealing strip used as a comparative example.

[0019] Figure 7 This is a diagram showing the structure of the sealing strip used as a comparative example.

[0020] Figure 8 This is a table showing the relationship between the substrate's deflection and distance A.

[0021] Figure 9 This is a diagram illustrating a structural example of a sealing strip with a third upper surface and an inclined surface on its inner periphery.

[0022] Figure 10 This is a diagram illustrating a structural example of a sealing strip with a third upper surface and an inclined surface on its inner periphery.

[0023] Figure 11 This is a diagram illustrating a structural example of a sealing strip where the entire upper surface of the inner circumference is inclined.

[0024] Figure 12 This is a diagram illustrating a structural example of a sealing strip with an inclined upper surface and a vertical surface on its inner periphery.

[0025] Figure 13 This is a diagram illustrating a structural example of a sealing strip with an inclined upper surface and a vertical surface on its inner periphery. Detailed Implementation

[0026] Hereinafter, various embodiments of the present invention will be described.

[0027] In one exemplary embodiment, an electrostatic chuck for holding a substrate is provided. The electrostatic chuck includes: a dielectric component for holding the substrate; and an electrostatic electrode disposed within the dielectric component. The dielectric component includes: a first upper surface having a gas outflow portion for gas outflow; and an annular sealing strip disposed outside the first upper surface and having a height higher than the first upper surface. The sealing strip includes: an outer peripheral portion; and an inner peripheral portion having a height lower than the outer peripheral portion. The electrostatic electrode is disposed at least directly below the inner peripheral portion of the sealing strip.

[0028] In one exemplary embodiment, the outer periphery of the sealing strip has a flat second upper surface, and the inner periphery of the sealing strip has a flat third upper surface.

[0029] In one exemplary embodiment, the upper surface of the inner periphery of the sealing strip also has an inclined surface.

[0030] In one exemplary embodiment, the third upper surface is lower than the second upper surface and higher than the first upper surface.

[0031] In one exemplary embodiment, the third upper surface is at least 0.1 μm lower than the second upper surface.

[0032] In one exemplary embodiment, the third upper surface is at least 3 μm higher than the first upper surface.

[0033] 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.

[0034] In one exemplary embodiment, the upper surface of the inner periphery of the sealing strip has only a third upper surface.

[0035] In one exemplary embodiment, the dielectric component further has a plurality of protrusions disposed on the first upper surface and projecting upward relative to the first upper surface.

[0036] In one exemplary embodiment, the protrusion has a height that is the same as or lower than the outer periphery of the sealing strip.

[0037] In one exemplary embodiment, the protrusion has a height ranging from 5 μm to 50 μm.

[0038] In one exemplary embodiment, the inner end of the inner periphery of the sealing strip is located between the outer end of the outermost protrusion and the inner end of the outer periphery of the sealing strip.

[0039] In one exemplary embodiment, the inner end of the inner periphery of the sealing strip is located inside the radial midpoint between the outer end of the outermost protrusion and the inner end of the outer periphery of the sealing strip.

[0040] In one exemplary embodiment, the inner periphery of the sealing strip has a height that is more than half the height of the protrusion.

[0041] In one exemplary embodiment, an electrostatic electrode is disposed directly below the sealing strip from directly below the first upper surface, with the outer end of the electrostatic electrode located further outward than the radial center of the inner periphery of the sealing strip.

[0042] In one exemplary embodiment, the outer end of the electrostatic electrode is located directly below the outer periphery of the sealing strip.

[0043] In one exemplary embodiment, the outer periphery of the sealing strip has a radial width in the range of 0.3 mm to 4 mm.

[0044] In one exemplary embodiment, the radial width of the inner circumference of the sealing strip is in the range of 1 mm to 36 mm.

[0045] In one exemplary embodiment, the radial width of the inner periphery of the sealing strip is greater than the radial width of the outer periphery of the sealing strip.

[0046] In one exemplary embodiment, the upper surface of the inner periphery of the sealing strip is entirely inclined.

[0047] In one exemplary embodiment, the inner periphery of the sealing strip has an inclined upper surface and a vertical surface that are radially interconnected.

[0048] In one exemplary embodiment, the thickness of the dielectric component in the vertical direction is in the range of 0.5 mm to 5 mm.

[0049] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, identical or similar elements are labeled with the same reference numerals, and repeated descriptions are omitted. Unless otherwise specified, positional relationships (top, bottom, left, right, etc.) are described based on the positional relationships shown in the drawings. The scale of the drawings does not represent an actual scale, and the actual scale is not limited to the scale shown in the drawings.

[0050] <An example of a plasma processing device>

[0051] Figure 1 This is a diagram illustrating a structural example of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing apparatus 1 and a control unit 2. The plasma processing system is an example of a substrate processing system, and the plasma processing apparatus 1 is an example of a substrate processing apparatus. The plasma processing apparatus 1 includes a plasma processing chamber 10, a substrate support 11, and a plasma generation unit 12. The plasma processing chamber 10 has a plasma processing space. Furthermore, the plasma processing chamber 10 has at least one gas supply port for supplying at least one type of processing gas to the plasma processing space; and at least one gas outlet for discharging gas from the plasma processing space. The gas supply port is connected to the gas supply unit 20 (described later), and the gas outlet is connected to the exhaust system 40 (described later). The substrate support 11 is disposed within the plasma processing space and has a substrate support surface for supporting a substrate.

[0052] The plasma generation unit 12 is capable of generating plasma from at least one type of processing gas supplied to the plasma processing space. The plasma formed in the plasma processing space can be capacitively coupled plasma (CCP), inductively coupled plasma (ICP), electron-cyclotron-resonance plasma (ECR), helicon wave plasma (HWP), or surface wave plasma (SWP), etc. Furthermore, various types of plasma generation units, including AC (Alternating Current) plasma generation units and DC (Direct Current) plasma generation units, can be used. In one embodiment, the AC signal (AC power) used in the AC plasma generation unit has a frequency in the range of 100 kHz to 10 GHz. Therefore, the AC signal includes both RF (Radio Frequency) and microwave signals. In one embodiment, the RF signal has a frequency in the range of 100 kHz to 150 MHz.

[0053] The control unit 2 is capable of processing computer-executable commands to cause the plasma processing apparatus 1 to perform the various processes described herein. The control unit 2 is capable of controlling the various elements of the plasma processing apparatus 1 to perform the various processes described herein. In one embodiment, the control unit 2 may be part or entirely included in the plasma processing apparatus 1. The control unit 2 may, for example, include a computer 2a. The computer 2a may, for example, include a processing unit (CPU) 2a1, a storage unit 2a2, and a communication interface 2a3. The processing unit 2a1 is capable of reading programs from the storage unit 2a2 and performing various control actions by executing the read programs. The programs may be pre-stored in the storage unit 2a2 or retrieved via a medium when needed. The retrieved programs are stored in the storage unit 2a2 and read and executed by the processing unit 2a1. The medium may be various storage media readable by the computer 2a or a communication line connected to the communication interface 2a3. The storage unit 2a2 may include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof. The communication interface 2a3 can communicate with the plasma processing device 1 via a communication line such as a LAN (Local Area Network).

[0054] The following describes a structural example of a capacitively coupled plasma processing device, which is an example of plasma processing device 1. Figure 2 This is a diagram illustrating a structural example of a capacitively coupled plasma processing device.

[0055] The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply 30, and an exhaust system 40. Furthermore, the plasma processing apparatus 1 includes a substrate support 11 and a gas inlet. The gas inlet is capable of introducing at least one processing gas into the plasma processing chamber 10. The gas inlet includes a spray head 13. The substrate support 11 is disposed within the plasma processing chamber 10. The spray head 13 is disposed above the substrate support 11. In one embodiment, the spray head 13 constitutes at least a portion of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the spray head 13, the sidewall 10a of the plasma processing chamber 10, and the substrate support 11. The plasma processing chamber 10 is grounded. The spray head 13 and the substrate support 11 are electrically insulated from the housing of the plasma processing chamber 10.

[0056] The substrate support portion 11 includes a main body portion 111 and a ring assembly 112. The main body portion 111 has a central region 111a for supporting a substrate W and an annular region 111b for supporting the ring assembly 112. A wafer is an example of a substrate W. The annular region 111b of the main body portion 111 surrounds the central region 111a of the main body portion 111 when viewed from above. The substrate W is disposed on the central region 111a of the main body portion 111, and the ring assembly 112 is disposed on the annular region 111b of the main body portion 111 in such a way that it surrounds the substrate W on the central region 111a of the main body portion 111. Therefore, the central region 111a is also referred to as a substrate support surface for supporting the substrate W, and the annular region 111b is also referred to as an annular support surface for supporting the ring assembly 112.

[0057] In one embodiment, the main body 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive component. The conductive component of the base 1110 can function as a lower electrode. The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic component 1111a and an electrostatic electrode 1111b disposed within the ceramic component 1111a. The ceramic component 1111a is an example of a dielectric component. The ceramic component 1111a has a central region 111a. In one embodiment, the ceramic component 1111a also has an annular region 111b. Alternatively, other components surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating component, may have an annular region 111b. In this case, the ring assembly 112 may be disposed on the annular electrostatic chuck or the annular insulating component, or on both the electrostatic chuck 1111 and the annular insulating component. Furthermore, an RF or DC electrode can be disposed within the ceramic component 1111a, in which case the RF or DC electrode can function as a lower electrode. When the bias RF signal or DC signal is connected to the RF / DC electrode (described later), the RF or DC electrode is also referred to as a bias electrode. Alternatively, the conductive component of the base 1110 and the RF or DC electrode can both function as two lower electrodes.

[0058] The ring assembly 112 includes one or more annular components. In one embodiment, the one or more annular components 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.

[0059] Furthermore, the substrate support 11 may include a temperature control module for adjusting at least one of the electrostatic chuck 1111, the ring assembly 112, and the substrate to a target temperature. The temperature control module may include a heater, a heat transfer medium, a flow path 1110a, or a combination thereof. The flow path 1110a may be formed within the substrate support 11, in which a heat transfer fluid such as brine or gas flows. The flow path 1110a may also be disposed within the electrostatic chuck 1111 or the base 1110. The flow path 1110a can be connected to a refrigerant supply device 1110b. Refrigerant with a temperature set by the refrigerant supply device 1110b can circulate within the flow path 1110a, thereby cooling the electrostatic chuck 1111 and the substrate W held on the electrostatic chuck 1111. In one embodiment, the flow path 1110a is formed within the base 1110, and one or more heaters are disposed within the ceramic component 1111a of the electrostatic chuck 1111. In addition, the substrate support portion 11 may include a heat transfer gas supply portion for supplying heat transfer gas to the gap between the back surface of the substrate W and the central region 111a.

[0060] The spray head 13 is capable of introducing at least one type of process gas from the gas supply unit 20 into the plasma processing space 10s. The spray head 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and multiple gas inlets 13c. The process gas supplied to the gas supply port 13a can be introduced into the plasma processing space 10s through the gas diffusion chamber 13b and the multiple gas inlets 13c. In addition, the spray head 13 includes an upper electrode. Furthermore, the gas inlet unit may include, in addition to the spray head 13, one or more side gas injectors (SGIs) mounted in one or more openings formed on the sidewall 10a.

[0061] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is capable of supplying at least one type of processing gas from its respective gas source 21 to the spray head 13 via its respective flow controller 22. Each flow controller 22 may, for example, include a mass flow controller or a pressure-controlled flow controller. Furthermore, the gas supply unit 20 may include at least one flow modulation device for modulating or pulsed the flow rate of the at least one type of processing gas.

[0062] The power supply 30 includes an RF power supply 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is capable of supplying 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 allows plasma to be formed from at least one type of processing gas supplied to the plasma processing space 10s. Therefore, the RF power supply 31 can function as at least a part of the plasma generation unit 12. Furthermore, by supplying a bias RF signal to at least one lower electrode, a bias potential can be generated on the substrate W, introducing ionic components from the formed plasma into the substrate W.

[0063] In one embodiment, the RF power supply 31 includes a first RF generation unit 31a and a second RF generation unit 31b. The first RF generation unit 31a is coupled to at least one lower electrode and / or at least one upper electrode via at least one impedance matching circuit, and is capable of generating a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 10MHz to 150MHz. In one embodiment, the first RF generation unit 31a may be capable of generating multiple source RF signals with 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.

[0064] The second RF generation unit 31b is coupled to at least one lower electrode via at least one impedance matching circuit and is capable of generating 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 that of the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 100 kHz to 60 MHz. In one embodiment, the second RF generation unit 31b may be capable of generating multiple bias RF signals with different frequencies. The generated one or more bias RF signals are supplied to at least one lower electrode. Furthermore, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0065] Furthermore, the power supply 30 may include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generating unit 32a and a second DC generating unit 32b. In one embodiment, the first DC generating unit 32a is connected to at least one lower electrode and is capable of generating a first DC signal. The generated first DC signal is applied to at least one lower electrode. In one embodiment, the second DC generating unit 32b is connected to at least one upper electrode and is capable of generating a second DC signal. The generated second DC signal is applied to at least one upper electrode.

[0066] In various embodiments, the first DC signal and the second DC signal can 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 can have a pulse waveform with a rectangular, trapezoidal, triangular, or combination thereof shape. In one embodiment, a waveform generation unit for generating a sequence of voltage pulses from the DC signal is connected between the first DC generation unit 32a and at least one lower electrode. Therefore, the first DC generation unit 32a and the waveform generation unit constitute a voltage pulse generation unit. When the second DC generation unit 32b and the waveform generation unit constitute a voltage pulse generation unit, the voltage pulse generation unit is connected to at least one upper electrode. The voltage pulses can be positive or negative. Furthermore, the sequence of voltage pulses can include one or more positive voltage pulses and one or more negative voltage pulses within one cycle. Alternatively, the first DC generation unit 32a and the second DC generation unit 32b can be provided in addition to the RF power supply 31, or the first DC generation unit 32a can be provided instead of the second RF generation unit 31b.

[0067] The exhaust system 40 can be connected, for example, to a gas outlet 10e located at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure within the plasma processing space 10s can be regulated using the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0068] <Example of the structure of an electrostatic chuck>

[0069] Figure 3 This is a diagram illustrating a structural example of the electrostatic chuck 1111 according to the embodiment shown in this example. In one embodiment, the electrostatic chuck 1111 has a ceramic component 1111a as a dielectric component and an electrostatic electrode 1111b.

[0070] In one embodiment, the ceramic component 1111a has a first upper surface 200 and a sealing strip 201, which is an annular protrusion disposed outside the first upper surface 200. The sealing strip 201 has a height higher than the first upper surface 200. The sealing strip 201 can be integrally formed with other parts, including the first upper surface 200, in the ceramic component 1111a, or it can be formed separately.

[0071] Figure 4This diagram illustrates a structural example of the ceramic component 1111a as viewed from above. In one embodiment, the first upper surface 200 has a circular shape centered on the center of the ceramic component 1111a. The sealing strip 201 has an annular shape centered on the center of the ceramic component 1111a. By providing such an annular sealing strip 201, the electrostatically adsorbed substrate W contacts the upper surface of the sealing strip 201, preventing heat transfer gas from leaking from the space between the back of the substrate W and the electrostatic chuck 1111 into the plasma processing space 10s.

[0072] In one implementation, such as Figure 3 As shown, the first upper surface 200 has a gas outlet 210 through which heat transfer gas flows out. In one embodiment, the gas outlet 210 is connected to a heat transfer gas supply unit 212 via a gas flow path 211. The gas flow path 211 can pass through the interior of the substrate support 11. The heat transfer gas supply unit 212 can be located outside the chamber 10. One or more gas outlets 210 can be provided. The heat transfer gas can be a helium-containing gas.

[0073] In one embodiment, a plurality of columnar protrusions 220 are disposed on the first upper surface 200. In one embodiment, the protrusions 220 project upward relative to the first upper surface 200. In one embodiment, the protrusions 220 have a cylindrical shape. In one embodiment, as... Figure 4 As shown, the plurality of protrusions 220 can be arranged at equal intervals along the circumference around the center of the first upper surface 200. The plurality of protrusions 220 can be arranged in a concentric circle or radial pattern relative to the center of the first upper surface 200.

[0074] In one implementation, such as Figure 3 As shown, the sealing strip 201 includes an annular outer peripheral portion 240 and an annular inner peripheral portion 241 having a lower height than the outer peripheral portion 240. The outer peripheral portion 240 is located outside the radial direction X of the inner peripheral portion 241. Figure 5 This is a diagram showing an example of the structure of the sealing strip 201 after the peripheral portion of the sealing strip 201 has been enlarged.

[0075] In one embodiment, the outer peripheral portion 240 has a flat second upper surface 250. In another embodiment, the outer peripheral portion 240 has a chamfered portion 251 at the outermost periphery of the upper surface.

[0076] In one embodiment, the inner peripheral 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 peripheral portion 241. However, as will be described later, protrusions may be provided on the upper surface of the inner peripheral portion 241.

[0077] 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 sequentially with increasing radial direction X. To ensure that the heat transfer gas can enter the gap between the substrate W and the inner periphery 241, the second upper surface 250 is configured such that even if the substrate W warps, the substrate W will not contact the second upper surface 250. Therefore, it is preferable that the third upper surface 260 is at least 0.1 μm lower than the second upper surface 250.

[0078] 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, increasing the electrostatic attraction to the substrate W at the inner periphery 241. Consequently, the electrostatic attraction of the sealing strip 201 to the substrate W is ensured. Preferably, the third upper surface 260 is at least 3 μm higher than the first upper surface 200. Furthermore, the height difference ΔH between the third upper surface 260 and the second upper surface 250 (or the upper surface of the protrusion 220) is preferably within 7 μm. The third upper surface 260 can have a height H2 that is more than half the height H1 of the protrusion 220, based on the first upper surface 200. Additionally, the vertical distance L1 from the third upper surface 260 to the electrostatic electrode 1111b can be in the range of 100 μm to 750 μm.

[0079] A columnar or annular protrusion may also be provided on the third upper surface 260. By providing a protrusion that is closer to the substrate W than the third upper surface 260, the electrostatic attraction to the substrate W can be further increased in the inner periphery 241. However, when a protrusion is provided on the third upper surface 260, there is a problem that the contact pressure between the substrate W and the outer periphery 240 weakens due to the contact between the upper surface of the protrusion and the substrate W, leading to leakage of heat transfer gas. Therefore, it is preferable not to provide a protrusion on the third upper surface 260, or even if a protrusion is provided, its upper surface should be lower than the second upper surface 250. Furthermore, from the viewpoint of maximizing electrostatic attraction, it is preferable that the protrusion is formed in an annular shape. However, when the protrusion is formed in an annular shape, there is a problem that the space between the protrusion and the outer periphery 240 may be blocked due to the bending of the substrate, preventing heat transfer gas from entering the space. Therefore, it is preferable to form a columnar shape when a protrusion is formed.

[0080] An inner peripheral portion 241 is disposed between the outermost protrusion 220 and the outer peripheral portion 240. That is, the inner end portion 241a of the inner peripheral portion 241 is located between the outer end portion 220a of the outermost protrusion 220 and the inner end portion 240a of the outer peripheral portion 240. Furthermore, to ensure sufficient electrostatic attraction, the area of ​​the inner peripheral portion 241 is preferably as large as possible. Therefore, it is preferable that the inner end portion 241a of the inner peripheral portion 241 is located further inward than the midpoint P1 of the radial direction X between the outer end portion 220a of the outermost protrusion 220 and the inner end portion 240a of the outer peripheral portion 240. The inner peripheral portion 241 can be formed up to the outer end portion 220a of the outermost protrusion 220. Furthermore, it is preferable that the radial width D2 of the inner peripheral portion 241 is greater than the radial width D1 of the outer peripheral portion 240.

[0081] However, if the area of ​​the inner periphery 241 is too large, the substrate W will come into contact with the third upper surface 260 due to the bending of the substrate W. Figure 8 It represents the distance A between the outermost protrusion 220 and the inner end 240a of the outer peripheral portion 240. Figure 5 The table shows the relationship between the inner peripheral portion 241 and the deflection of the substrate W. The inner peripheral portion 241 can extend inward to the position of the outermost circumferential protrusion 220; however, when the radial width D2 of the inner peripheral portion 241 is within 36 mm, the deflection of the substrate W becomes approximately 7 μm or less. Therefore, it is preferable that the radial width D2 of the inner peripheral portion 241 is within the range of 1 mm to 36 mm.

[0082] The protrusion 220 may have a height H1 that is the same as or lower than that of the outer peripheral portion 240. The height H1 of the protrusion 220 may be in the range of 5 μm to 50 μm.

[0083] The radial width D1 of the outer peripheral portion 240 can be in the range of 0.3 mm to 4 mm.

[0084] like Figure 3 As shown, the electrostatic electrode 1111b is located within the ceramic component 1111a and can be disposed directly below the first upper surface 200 and the sealing strip 201. 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 attraction (Coulomb force) is generated between the ceramic component 1111a and the substrate W. The substrate W is attracted to the ceramic component 1111a by this electrostatic attraction and is held adsorbed on the upper surface of the ceramic component 1111a.

[0085] In one implementation, such as Figure 5As shown, the electrostatic electrode 1111b is positioned directly below the sealing strip 201 from directly below the first upper surface 200. The electrostatic electrode 1111b can be positioned at least directly below the inner peripheral portion 241. The outer end portion 1111b-1 of the electrostatic electrode 1111b can be located outside the center position P2 of the radial direction X of the inner peripheral portion 241. The outer end portion 1111b-1 can be located directly below the outer peripheral portion 240.

[0086] like Figure 3 As shown, the thickness L2 of the ceramic component 1111a in the vertical direction can be in the range of 0.5 mm to 5 mm.

[0087] <An example of a plasma processing method>

[0088] The plasma processing method includes an etching process that uses plasma 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.

[0089] First, such as Figure 2 As shown, the substrate W is fed into the chamber 10 and placed on the substrate support 11. The substrate W is as follows... Figure 3 As shown, it is held by the electrostatic chuck 1111. At this time, the substrate W is placed on the ceramic component 1111a and in contact with the outer periphery 240 of the sealing strip 201. A DC voltage is applied to the electrostatic electrode 1111b, generating electrostatic attraction between the sealing strip 201 and the substrate W, and the substrate W is attracted to the sealing strip 201.

[0090] exist Figure 2 The substrate support 11 shown supplies refrigerant from the refrigerant supply device 1110b to the flow path 1110a, and the electrostatic chuck 1111 and the substrate W held on the electrostatic chuck 1111 are heated to a specified temperature.

[0091] Heat transfer gas is supplied from the heat transfer gas supply section 212 to the gas outlet section 210, and from the gas outlet section 210, heat transfer gas is supplied to the space formed between the substrate W and the first upper surface 200. Heat transfer gas is also supplied to the space formed between the substrate W and the third upper surface 260. The sealing strip 201 seals the space between the first upper surface 200 and the substrate W in such a way that the heat transfer gas does not leak into the plasma processing space for 10 seconds. The heat transfer gas regulates the temperature of the substrate W from its inside.

[0092] Next, the processing gas was Figure 2 The gas supply unit 20 shown supplies gas to the spray head 13 and from the spray head 13 to the plasma processing space 10s. The processing gas supplied at this time contains the gas required to generate the active species for the etching process of the substrate W.

[0093] One or more RF signals are supplied from the RF power supply 31 to the upper electrode and / or the lower electrode. Alternatively, the atmospheric gas within the plasma processing space 10s can be exhausted from the gas outlet 10e, thus depressurizing the interior of the plasma processing space 10s. Consequently, plasma is generated on the substrate support 11 within the plasma processing space 10s, and the substrate W is etched. During plasma processing... Figure 3 The gas outlet 210 shown supplies heat transfer gas to the back side of the substrate W and cools the substrate W at the outer periphery 240 of the sealing strip 201 after it has been conditioned by the refrigerant.

[0094] In the embodiment illustrated here, the ceramic component 1111a of the electrostatic chuck 1111 has a first upper surface 200 and an annular sealing strip 201. The sealing strip 201 includes an outer peripheral portion 240 and an inner peripheral portion 241 having a lower height than the outer peripheral portion 240. The electrostatic electrode 1111b is disposed at least directly below the inner peripheral portion 241. This allows a gap to be created between the inner peripheral portion 241 of the sealing strip 201 and the substrate W. Heat transfer gas reaches this gap in the inner peripheral portion 241 and is transferred to the outer peripheral portion of the substrate W by adjusting the temperature of the substrate W using the heat transfer gas. Furthermore, since the inner peripheral portion 241 of the sealing strip 201 is closer to the substrate W than the first upper surface 200, the electrostatic attraction of the inner peripheral portion 241 of the sealing strip 201 to the substrate W is greater than that of 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 strongly adsorbed onto the outer periphery 240. As a result, the tiny gaps that may occur between the substrate W and the outer periphery 240 due to surface roughness, etc., are reduced, the contact area between the substrate W and the outer periphery 240 increases, and heat is efficiently transferred between the electrostatic chuck 1111 and the outer periphery of the substrate W. As a result, the outer periphery of the substrate W can be adequately cooled during plasma processing, and the temperature uniformity of the substrate held in the electrostatic chuck 1111 can be improved.

[0095] <Example>

[0096] (1) As an example, regarding the case where the inner peripheral portion 241 is lower than the outer peripheral portion 240 of the sealing strip 201, as in the embodiment shown in this example, (2) as a comparative example, regarding the case where the inner peripheral portion 241 is lower than the outer peripheral portion 240 of the sealing strip 201, Figure 6 As shown, when the sealing strip 201 has an inner peripheral portion 500 at the same height as the outer peripheral portion 240, (3) as a comparative example, regarding the case where ... Figure 7As shown, when the sealing strip 201 has an inner peripheral portion 501 with the same height as the first upper surface 200, the contact pressure of the sealing strip 201 on the substrate is compared. Furthermore, the radial width X of the outer peripheral portion 240 is 1.7 mm, and the radial width X of the inner peripheral portions 241 (500, 501) is 1.8 mm. In addition, in (1), the height difference ΔH between the third upper surface 260 and the second upper surface 250 is 5 μm. In (2), compared to (1), the radial width of the outer peripheral portion 240 of the sealing strip 20 is substantially larger, and the contact area between the substrate W and the sealing strip 201 is larger. In (3), compared to (1), the contact area between the substrate W and the sealing strip 201 is the same, but the distance between the inner peripheral portion 501 and the substrate W is larger. The result of applying the same voltage to the electrostatic electrodes 1111b in (1) to (3) is that the contact pressure is 17.7 kPa in (1), 14.3 kPa in (2), and 16.0 kPa in (3). As a result, it can be confirmed that, in case (1), heat is transferred between the substrate W and the sealing strip 201 compared to cases (2) and (3). In fact, the result of measuring the temperature of the outer periphery of the substrate W when the substrate W is held by the electrostatic chuck 1111 and cooled from the electrostatic chuck 1111 is that, in case (1), a low temperature effect of about 1.5°C to 2.2°C is obtained compared to cases (2) and (3).

[0097] In the above embodiment, the upper surface of the inner circumference 241 of the sealing strip 201 only has a third upper surface 260, but it may also have an inclined surface. In one embodiment, such as Figure 9 As shown, the inner circumference 241 of the sealing strip 201 has a third upper surface 260 and an inclined surface 310 on its upper surface. The inclined surface 310 and the third upper surface 260 can be connected to each other. The inclined surface 310 can be connected at one end to the first upper surface 200 and at the other end to the third upper surface 260. In one embodiment, it can be as follows: Figure 10 As shown, one end of the inclined surface 310 is connected to the second upper surface 250, and the other end is connected to the third upper surface 260.

[0098] In one implementation, it can be as follows: Figure 11 As shown, the upper surface of the inner periphery 241 of the sealing strip 201 is generally inclined surface 310.

[0099] In one implementation, it can be as follows: Figure 12As shown, the inner circumference 241 of the sealing strip 201 has an inclined upper surface 320 and a vertical surface 321 that are interconnected in the radial direction X. The inclined upper surface 320 may be connected at one end to the first upper surface 200 and at the other end to the vertical surface 321. The vertical surface 321 may be connected at one end to the inclined upper surface 320 and at the other end to the second upper surface 250.

[0100] In one implementation, it can be as follows: Figure 13 As shown, one end of the vertical surface 321 is connected to the first upper surface 200, and the other end is connected to the inclined upper surface 320. The inclined upper surface 320 may be connected to the vertical surface 321 at one end and to the second upper surface 250 at the other end.

[0101] Through this inclined surface, and Figure 5 Compared to the case shown which only has a flat third upper surface 260, the electrostatic attraction to the substrate W can be increased, and the substrate W can be strongly adsorbed to the outer periphery 240.

[0102] In the above embodiments, an example of using the electrostatic chuck 1111 in a capacitively coupled plasma device has been described; however, it is not limited to this and can also be used in other types of plasma devices. Furthermore, the electrostatic chuck 1111 is not limited to plasma processing devices and can also be used in other substrate processing devices.

[0103] The embodiments of the present invention include the following methods.

[0104] (Note 1)

[0105] An electrostatic chuck for holding a substrate, comprising:

[0106] Dielectric components for mounting a substrate; and

[0107] Electrostatic electrodes disposed within the dielectric component,

[0108] The dielectric component includes:

[0109] The first upper surface has a gas outlet for gas to flow out; and

[0110] An annular sealing strip, disposed on the outer side of the first upper surface, has a height higher than the first upper surface.

[0111] The sealing strip includes:

[0112] Peripheral part; and

[0113] An inner peripheral portion having a lower height than the outer peripheral portion,

[0114] The electrostatic electrode is disposed at least directly below the inner periphery of the sealing strip.

[0115] (Note 2)

[0116] The electrostatic chuck described in Appendix 1, among which,

[0117] The outer periphery of the sealing strip has a flat second upper surface.

[0118] The inner circumference of the sealing strip has a flat third upper surface.

[0119] (Note 3)

[0120] The electrostatic chuck described in Appendix 2, among which,

[0121] The upper surface of the inner periphery of the sealing strip also has an inclined surface.

[0122] (Note 4)

[0123] The electrostatic chuck described in Appendix 2 or 3, wherein,

[0124] The third upper surface is lower than the second upper surface and higher than the first upper surface.

[0125] (Note 5)

[0126] The electrostatic chuck described in any of notes 2 to 4, wherein,

[0127] The third upper surface is at least 0.1 μm lower than the second upper surface.

[0128] (Note 6)

[0129] The electrostatic chuck described in any of notes 2 to 5, wherein,

[0130] The third upper surface is more than 3 μm higher than the first upper surface.

[0131] (Note 7)

[0132] The electrostatic chuck described in any of notes 2 to 6, wherein,

[0133] The distance from the third upper surface to the electrostatic electrode is in the range of 100 μm to 750 μm.

[0134] (Note 8)

[0135] The electrostatic chuck described in any of notes 2 to 7, wherein,

[0136] The upper surface of the inner circumference of the sealing strip has only the third upper surface.

[0137] (Note 9)

[0138] The electrostatic chuck described in any of the notes 1 to 8, wherein,

[0139] The dielectric component also has a plurality of protrusions disposed on the first upper surface and protruding upward relative to the first upper surface.

[0140] (Postscript 10)

[0141] The electrostatic chuck described in Appendix 9, among which,

[0142] The protrusion has a height that is the same as or lower than the outer periphery of the sealing strip.

[0143] (Postscript 11)

[0144] The electrostatic chuck described in Appendix 9 or 10, wherein,

[0145] The protrusion has a height ranging from 5 μm to 50 μm.

[0146] (Postscript 12)

[0147] The electrostatic chuck described in any of notes 9 to 11, wherein,

[0148] The inner end of the inner periphery of the sealing strip is located between the outer end of the outermost protrusion and the inner end of the outer periphery of the sealing strip.

[0149] (Postscript 13)

[0150] The electrostatic chuck described in any of notes 9 to 12, wherein,

[0151] The inner end of the inner periphery of the sealing strip is located inside the radial midpoint between the outer end of the outermost protrusion and the inner end of the outer periphery of the sealing strip.

[0152] (Postscript 14)

[0153] The electrostatic chuck described in any of the notes 9 to 13, wherein,

[0154] The inner circumference of the sealing strip has a height that is more than half the height of the protrusion.

[0155] (Postscript 15)

[0156] The electrostatic chuck described in any of the notes 1 to 14, wherein,

[0157] The electrostatic electrode is positioned directly below the first upper surface and directly below the sealing strip.

[0158] The outer end of the electrostatic electrode is located further outward than the radial center of the inner circumference of the sealing strip.

[0159] (Postscript 16)

[0160] The electrostatic chuck described in Appendix 15, among which,

[0161] The outer end of the electrostatic electrode is located directly below the outer periphery of the sealing strip.

[0162] (Postscript 17)

[0163] The electrostatic chuck described in any of the notes 1 to 16, wherein,

[0164] The radial width of the outer periphery of the sealing strip is in the range of 0.3 mm to 4 mm.

[0165] (Postscript 18)

[0166] The electrostatic chuck described in any of the notes 1 to 17, wherein,

[0167] The radial width of the inner circumference of the sealing strip is in the range of 1 mm to 36 mm.

[0168] (Postscript 19)

[0169] The electrostatic chuck described in any of the notes 1 to 18, wherein,

[0170] The radial width of the inner circumference of the sealing strip is greater than the radial width of the outer circumference of the sealing strip.

[0171] (Postscript 20)

[0172] The electrostatic chuck described in any of the notes 1 to 19, wherein,

[0173] The upper surface of the inner periphery of the sealing strip is generally inclined.

[0174] (Postscript 21)

[0175] The electrostatic chuck described in any of the notes 1 to 20, wherein,

[0176] The inner periphery of the sealing strip has an inclined upper surface and a vertical surface that are radially connected to each other.

[0177] (Postscript 22)

[0178] The electrostatic chuck described in any of the notes 1 to 21, wherein,

[0179] The thickness of the dielectric component in the vertical direction is in the range of 0.5 mm to 5 mm.

[0180] The above embodiments are described for illustrative purposes only and are not intended to limit the scope of the present invention. Various modifications can be made to the above embodiments without departing from the scope and spirit of the present invention. For example, some components of one embodiment can be added to other embodiments. Furthermore, some components of one embodiment can be replaced with corresponding components of other embodiments.

[0181] Explanation of reference numerals in the attached figures

[0182] 1: Plasma processing device; 10: Chamber; 11: Substrate support; 112: Ring assembly; 1111: Electrostatic chuck; 1111a: Ceramic component; 1111b: Electrostatic electrode; 200: First upper surface; 201: Sealing strip; 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, comprising: Dielectric components that mount a substrate; and Electrostatic electrodes disposed within the dielectric component, The dielectric component includes: The first upper surface has a gas outlet for gas to flow out; and An annular sealing strip, disposed on the outer side of the first upper surface, has a height higher than the first upper surface. The sealing strip includes: Peripheral part; and An inner peripheral portion having a lower height than the outer peripheral portion, The electrostatic electrode is disposed at least directly below the inner circumference of the sealing strip. The dielectric component also has a plurality of protrusions disposed on the first upper surface and protruding upward relative to the first upper surface. The inner end of the inner periphery of the sealing strip is located inside the radial midpoint between the outer end of the outermost protrusion and the inner end of the outer periphery of the sealing strip.

2. The electrostatic chuck as described in claim 1, wherein, The outer periphery of the sealing strip has a flat second upper surface. The inner circumference of the sealing strip has a flat third upper surface.

3. The electrostatic chuck as described in claim 2, wherein, The upper surface of the inner periphery of the sealing strip also has an inclined surface.

4. The electrostatic chuck as described in claim 2, wherein, The third upper surface is lower than the second upper surface and higher than the first upper surface.

5. The electrostatic chuck as described in claim 4, wherein, The third upper surface is at least 0.1 μm lower than the second upper surface.

6. The electrostatic chuck as described in claim 5, wherein, The third upper surface is more than 3 μm higher than the first upper surface.

7. The electrostatic chuck as described in claim 2, wherein, The distance from the third upper surface to the electrostatic electrode is in the range of 100 μm to 750 μm.

8. The electrostatic chuck as described in claim 2, wherein, The upper surface of the inner circumference of the sealing strip has only the third upper surface.

9. The electrostatic chuck as described in claim 1, wherein, The protrusion has the same height as or lower than the outer periphery of the sealing strip.

10. The electrostatic chuck as claimed in claim 1, wherein, The protrusion has a height ranging from 5 μm to 50 μm.

11. The electrostatic chuck as claimed in claim 1, wherein, The inner circumference of the sealing strip has a height that is more than half the height of the protrusion.

12. The electrostatic chuck as described in claim 1, wherein, The radial width of the outer periphery of the sealing strip is in the range of 0.3 mm to 4 mm.

13. The electrostatic chuck as described in claim 1, wherein, The radial width of the inner circumference of the sealing strip is in the range of 1 mm to 36 mm.

14. The electrostatic chuck as described in claim 1, wherein, The radial width of the inner circumference of the sealing strip is greater than the radial width of the outer circumference of the sealing strip.

15. The electrostatic chuck as described in claim 1, wherein, The upper surface of the inner periphery of the sealing strip is generally inclined.

16. The electrostatic chuck as claimed in claim 1, wherein, The inner periphery of the sealing strip has an inclined upper surface and a vertical surface that are radially connected to each other.

17. The electrostatic chuck as claimed in claim 1, wherein, The thickness of the dielectric component in the vertical direction is in the range of 0.5 mm to 5 mm.

18. The electrostatic chuck as described in any one of claims 1 to 17, wherein, The electrostatic electrode is positioned directly below the first upper surface and directly below the sealing strip. The outer end of the electrostatic electrode is located further outward than the radial center of the inner circumference of the sealing strip.

19. The electrostatic chuck as claimed in claim 18, wherein, The outer end of the electrostatic electrode is located directly below the outer periphery of the sealing strip.

20. An electrostatic chuck for holding a substrate, comprising: Dielectric components that mount a substrate; and Electrostatic electrodes disposed within the dielectric component, The dielectric component includes: The first upper surface has a gas outlet for gas to flow out; and An annular sealing strip, disposed on the outer side of the first upper surface, has a height higher than the first upper surface. The sealing strip includes: Peripheral part; and An inner peripheral portion having a lower height than the outer peripheral portion, The electrostatic electrode is disposed at least directly below the inner circumference of the sealing strip. The radial width of the inner circumference of the sealing strip is greater than the radial width of the outer circumference of the sealing strip.

21. The electrostatic chuck as described in claim 20, wherein, The dielectric component also has a plurality of protrusions disposed on the first upper surface and protruding upward relative to the first upper surface. The inner circumference of the sealing strip has a height that is more than half the height of the protrusion.

22. The electrostatic chuck as described in claim 20, wherein, The electrostatic electrode is positioned directly below the first upper surface and directly below the sealing strip. The outer end of the electrostatic electrode is located further outward than the radial center of the inner circumference of the sealing strip.

23. The electrostatic chuck as described in claim 22, wherein, The outer end of the electrostatic electrode is located directly below the outer periphery of the sealing strip.

24. The electrostatic chuck as described in any one of claims 20 to 23, wherein, The radial width of the outer periphery of the sealing strip is in the range of 0.3 mm to 4 mm.

25. The electrostatic chuck as described in claim 24, wherein, The radial width of the inner circumference of the sealing strip is in the range of 1 mm to 36 mm.

26. An electrostatic chuck for holding a substrate, comprising: Dielectric components that mount a substrate; and Electrostatic electrodes disposed within the dielectric component, The dielectric component includes: The first upper surface has a gas outlet for gas to flow out; and An annular sealing strip, disposed on the outer side of the first upper surface, has a height higher than the first upper surface. The sealing strip includes: Peripheral part; and An inner peripheral portion having a lower height than the outer peripheral portion, The electrostatic electrode is disposed at least directly below the inner circumference of the sealing strip. The outer periphery of the sealing strip has a flat second upper surface. The inner circumference of the sealing strip has a flat third upper surface.

27. An electrostatic chuck for holding a substrate, comprising: Dielectric components that mount a substrate; and Electrostatic electrodes disposed within the dielectric component, The dielectric component includes: The first upper surface has a gas outlet for gas to flow out; and An annular sealing strip, disposed on the outer side of the first upper surface, has a height higher than the first upper surface. The sealing strip includes: Peripheral part; and An inner peripheral portion having a lower height than the outer peripheral portion, The electrostatic electrode is disposed at least directly below the inner circumference of the sealing strip. The inner periphery of the sealing strip has an inclined upper surface and a vertical surface that are radially connected to each other.

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