Electrostatic chuck

Abstract

Provided is a technique capable of improving the temperature uniformity of a substrate held by an electrostatic chuck, the electrostatic chuck including: a dielectric member on which a substrate is placed; and an electrostatic electrode disposed in the dielectric member, the dielectric member including: a first upper surface having a gas outlet portion through which a gas flows out; and a ring-shaped seal band disposed outside the first upper surface and having a height higher than that of the first upper surface, the seal band including: an outer peripheral portion; and an inner peripheral portion having a height lower than that of the outer peripheral portion, the electrostatic electrode being disposed at least directly below the inner peripheral portion of the seal band.

Description

TECHNICAL FIELD

[0001] An exemplary embodiment of the present application relates to an electrostatic chuck. BACKGROUND

[0002] As a technique of providing an electrostatic chuck having a ring-shaped seal band that supports an outer peripheral portion of a substrate, there is a technique described in Patent Literature 1.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2021-15820 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] The present application provides a technique capable of improving temperature uniformity of a substrate held by an electrostatic chuck.

[0008] TECHNICAL MEANS FOR SOLVING THE PROBLEMS

[0009] An electrostatic chuck of one exemplary embodiment of the present application includes a dielectric member on which a substrate is placed, and an electrostatic electrode disposed in the dielectric member, the dielectric member including a first upper surface having a gas outlet portion through which a gas flows out, and a ring-shaped seal band disposed outside the first upper surface and having a height higher than that of the first upper surface, the seal band including an outer peripheral portion, and an inner peripheral portion having a height lower than that of the outer peripheral portion, the electrostatic electrode being disposed at least directly below the inner peripheral portion of the seal band.

[0010] EFFECTS OF THE INVENTION

[0011] According to one exemplary embodiment of the present application, a technique capable of improving temperature uniformity of a substrate held by an electrostatic chuck can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 is a view for explaining a structure example of a plasma processing system.

[0013] Figure 2 is a view for explaining a structure example of a plasma processing apparatus of a capacitive coupling type.

[0014] Figure 3 is a view showing a structure example of an electrostatic chuck in the present exemplary embodiment.

[0015] Figure 4 is a view showing a structure example of a ceramic as viewed from above.

[0016] Figure 5is a view showing a structure example of a seal tape after a peripheral portion of the seal tape is enlarged.

[0017] Figure 6 is a view showing a structure of a seal tape as a comparative example.

[0018] Figure 7 is a view showing a structure of a seal tape as a comparative example.

[0019] Figure 8 is a table showing a relationship between a deflection amount of a substrate and a distance A.

[0020] Figure 9 is a view showing a structure example of a seal tape in which an inner peripheral portion has a third upper surface and an inclined surface.

[0021] Figure 10 is a view showing a structure example of a seal tape in which an inner peripheral portion has a third upper surface and an inclined surface.

[0022] Figure 11 is a view showing a structure example of a seal tape in which an upper surface of an inner peripheral portion is entirely an inclined surface.

[0023] Figure 12 is a view showing a structure example of a seal tape in which an inner peripheral portion has an inclined upper surface and a vertical surface.

[0024] Figure 13 is a view showing a structure example of a seal tape in which an inner peripheral portion has an inclined upper surface and a vertical surface. DETAILED DESCRIPTION

[0025] Hereinafter, each embodiment of the present application will be described.

[0026] In one example embodiment, an electrostatic chuck that holds a substrate includes a dielectric member on which the substrate is placed, and an electrostatic electrode disposed in the dielectric member, the dielectric member including a first upper surface having a gas outlet portion through which a gas flows out, and a ring-shaped seal tape disposed outside the first upper surface and having a height higher than that of the first upper surface, the seal tape including an outer peripheral portion, and an inner peripheral portion having a height lower than that of the outer peripheral portion, the electrostatic electrode being disposed at least directly below the inner peripheral portion of the seal tape.

[0027] In one example embodiment, the outer peripheral portion of the seal tape has a flat second upper surface, and the inner peripheral portion of the seal tape has a flat third upper surface.

[0028] In one example embodiment, the upper surface of the inner peripheral portion of the seal tape further has an inclined surface.

[0029] In one example embodiment, the third upper surface is lower than the second upper surface and higher than the first upper surface.

[0030] In one illustrative embodiment, the third upper surface is lower than the second upper surface by 0.1 μm or more.

[0031] In one illustrative embodiment, the third upper surface is higher than the first upper surface by 3 μm or more.

[0032] In one illustrative embodiment, the third upper surface is located within a range of 100 μm to 750 μm from the electrostatic electrode.

[0033] In one illustrative embodiment, the upper surface of the inner peripheral portion of the sealing tape has only the third upper surface.

[0034] In one illustrative embodiment, the dielectric member further has a plurality of protrusions arranged on the first upper surface and protruding upward with respect to the first upper surface.

[0035] In one illustrative embodiment, the protrusions have a height that is the same as or lower than the outer peripheral portion of the sealing tape.

[0036] In one illustrative embodiment, the protrusions have a height within a range of 5 μm to 50 μm.

[0037] In one illustrative embodiment, the inner side end portion of the inner peripheral portion of the sealing tape is located between the outer side end portion of the protrusion located at the outermost side and the inner side end portion of the outer peripheral portion of the sealing tape.

[0038] In one illustrative embodiment, the inner side end portion of the inner peripheral portion of the sealing tape is located inward of a point that is radially intermediate between the outer side end portion of the protrusion located at the outermost side and the inner side end portion of the outer peripheral portion of the sealing tape.

[0039] In one illustrative embodiment, the inner peripheral portion of the sealing tape has a height that is half or more of the height of the protrusion.

[0040] In one illustrative embodiment, the electrostatic electrode is arranged directly below the sealing tape from directly below the first upper surface, and the electrostatic electrode has an outer side end portion located outward of a position that is radially central of the inner peripheral portion of the sealing tape.

[0041] In one illustrative embodiment, the electrostatic electrode has an outer side end portion located directly below the outer peripheral portion of the sealing tape.

[0042] In one illustrative embodiment, the outer peripheral portion of the sealing tape has a radial width within a range of 0.3 mm to 4 mm.

[0043] In one illustrative embodiment, the inner peripheral portion of the sealing tape has a radial width within a range of 1 mm to 36 mm.

[0044] In one illustrative embodiment, the inner peripheral portion of the seal band has a radial width that is greater than a radial width of the outer peripheral portion of the seal band.

[0045] In one illustrative embodiment, the upper surface of the inner peripheral portion of the seal band is an inclined surface as a whole.

[0046] In one illustrative embodiment, the inner peripheral portion of the seal band has an inclined upper surface and a vertical surface that are connected to each other in the radial direction.

[0047] In one illustrative embodiment, the dielectric member has a thickness in the vertical direction that is in a range of 0.5 mm to 5 mm.

[0048] Hereinafter, each embodiment of the present application will be described in detail with reference to the drawings. In the drawings, the same or similar elements are marked by the same reference numerals, and repetitive description is omitted. If not specifically reminded, the positional relationship of up, down, left, right, and the like is described based on the positional relationship shown in the drawings. The dimensional proportions of the drawings do not represent actual proportions, and furthermore, the actual proportions are not limited to the proportions shown in the drawings.

[0049] <Example of Plasma Processing Apparatus>

[0050] Figure 1 is a drawing for explaining a structure example of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing apparatus 1 and a control portion 2. The plasma processing system is one example of a substrate processing system, and the plasma processing apparatus 1 is one example of a substrate processing apparatus. The plasma processing apparatus 1 includes a plasma processing chamber 10, a substrate support portion 11, and a plasma generating portion 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 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 portion 20 described later, and the gas exhaust port is connected to an exhaust system 40 described later. The substrate support portion 11 is disposed in the plasma processing space, and has a substrate support surface for supporting a substrate.

[0051] The plasma generation portion 12 is capable of generating plasma from at least one kind of processing gas supplied into the plasma processing space. The plasma formed in the plasma processing space can be a capacitively coupled plasma (CCP), an inductively coupled plasma (ICP), an electron-cyclotron-resonance plasma (ECR), a helicon wave plasma (HWP), a surface wave plasma (SWP), or the like. Further, various types of plasma generation portions including an AC (Alternating Current) plasma generation portion and a DC (Direct Current) plasma generation portion can be used. In one embodiment, an AC signal (AC electric power) used in the AC plasma generation portion has a frequency in the range of 100 kHz to 10 GHz. Thus, the AC signal includes an RF (Radio Frequency) signal and a microwave signal. In one embodiment, the RF signal has a frequency in the range of 100 kHz to 150 MHz.

[0052] The control section 2 can process a computer executable command for causing the plasma processing apparatus 1 to execute various processes described in the present application. The control section 2 can control each element of the plasma processing apparatus 1 to execute various processes described herein. In one embodiment, a part or all of the control section 2 can be included in the plasma processing apparatus 1. The control section 2 can include, for example, a computer 2a. The computer 2a can include, for example, a processing section (CPU: Central Processing Unit) 2al, a storage section 2a2, and a communication interface 2a3. The processing section 2al can read a program from the storage section 2a2, and perform various control actions by executing the read program. The program can be stored in the storage section 2a2 in advance, or can be acquired via a medium as needed. The acquired program is stored in the storage section 2a2, and read from the storage section 2a2 by the processing section 2al to be executed. The medium can be various storage media readable by the computer 2a, or can be a communication line connected to the communication interface 2a3. The storage section 2a2 can include a RAM (Random Access Memory), a ROM (Read Only Memory), an HDD (Hard Disk Drive), an SSD (Solid State Drive), or a combination thereof. The communication interface 2a3 can communicate with the plasma processing apparatus 1 via a communication line such as a LAN (Local Area Network).

[0053] Next, a configuration example of a plasma processing apparatus of a capacitively coupled type as one example of the plasma processing apparatus 1 will be described. Figure 2 is a view for describing a configuration example of a plasma processing apparatus of a capacitively coupled type.

[0054] The plasma processing apparatus 1 of the capacitively coupled type includes a plasma processing chamber 10, a gas supply section 20, a power source 30, and an exhaust system 40. Further, the plasma processing apparatus 1 includes a substrate support section 11 and a gas introduction section. The gas introduction section can introduce at least one kind of processing gas into the plasma processing chamber 10. The gas introduction section includes a shower head 13. The substrate support section 11 is disposed in the plasma processing chamber 10. The shower head 13 is disposed above the substrate support section 11. In one embodiment, the shower head 13 constitutes 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 shower head 13, a side wall 10a of the plasma processing chamber 10, and the substrate support section 11. The plasma processing chamber 10 is grounded. The shower head 13 and the substrate support section 11 are electrically insulated from a housing of the plasma processing chamber 10.

[0055] 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 a ring-shaped region 111b for supporting the ring assembly 112. A wafer is an example of the substrate W. The ring-shaped region 111b of the main body portion 111 encloses the central region 111a of the main body portion 111 in plan view. 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 ring-shaped region 111b of the main body portion 111 so as to enclose 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 ring-shaped region 111b is also referred to as a ring support surface for supporting the ring assembly 112.

[0056] In one embodiment, the main body portion 111 includes a susceptor 1110 and an electrostatic chuck 1111. The susceptor 1110 includes an electrically conductive member. The electrically conductive member of the susceptor 1110 can function as a lower electrode. The electrostatic chuck 1111 is disposed on the susceptor 1110. The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic electrode 1111b disposed in the ceramic member 1111a. The ceramic member 1111a is an example of a dielectric member. The ceramic member 1111a has the central region 111a. In one embodiment, the ceramic member 1111a also has the ring-shaped region 111b. Alternatively, another member, such as a ring-shaped electrostatic chuck or a ring-shaped insulating member, which encloses the electrostatic chuck 1111, can have the ring-shaped region 111b. In this case, the ring assembly 112 can be disposed on the ring-shaped electrostatic chuck or the ring-shaped insulating member, or can be disposed on both the electrostatic chuck 1111 and the ring-shaped insulating member. Further, an RF or DC electrode can be disposed in the ceramic member 1111a, in which case the RF or DC electrode can function as a lower electrode. In the case where a bias RF signal or a DC signal is connected to the RF or DC electrode as described later, the RF or DC electrode is also referred to as a bias electrode. Alternatively, both the electrically conductive member of the susceptor 1110 and the RF or DC electrode can function as two lower electrodes.

[0057] The ring assembly 112 includes one or more ring-shaped members. In one embodiment, the one or more ring-shaped members include one or more edge rings and at least one cover ring. The edge ring is formed of an electrically conductive material or an insulating material, and the cover ring is formed of an insulating material.

[0058] Further, the substrate support 11 can include a temperature adjustment module for adjusting at least one of the electrostatic chuck 1111, the ring assembly 112, and the substrate to a target temperature. The temperature adjustment module can include a heater, a heat transfer medium, a flow path 1110a, or a combination thereof. The flow path 1110a, in which a heat transfer fluid such as brine or gas flows, can be formed in the substrate support 11. The flow path 1110a can also be provided in the electrostatic chuck 1111 or the susceptor 1110. The flow path 1110a can be connected to a refrigerant supply device 1110b. Refrigerant having a temperature set by the refrigerant supply device 1110b can flow and circulate in 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 in the susceptor 1110, and one or more heaters are disposed in a ceramic member 1111a of the electrostatic chuck 1111. Further, the substrate support 11 can include a heat transfer gas supply portion for supplying a heat transfer gas to a gap between a back surface of the substrate W and the central region 111a.

[0059] The shower head 13 can introduce at least one process gas from the gas supply portion 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 a plurality of gas introduction ports 13c. Process gas supplied to the gas supply port 13a can be introduced into the plasma processing space 10s through the gas diffusion chamber 13b from the plurality of gas introduction ports 13c. Further, the shower head 13 includes an upper electrode. In addition, the gas introduction portion can include one or more side gas injectors (SGIs) installed in one or more opening portions formed in the sidewall 10a, in addition to the shower head 13.

[0060] The gas supply portion 20 can include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply portion 20 can supply at least one process gas from each corresponding gas source 21 to the shower head 13 via each corresponding flow controller 22. Each flow controller 22 can include, for example, a mass flow controller or a pressure-controlled flow controller. Also, the gas supply portion 20 can include at least one flow modulation device for modulating or pulsing the flow of at least one process gas.

[0061] The power supply 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 capable of supplying at least one RF signal (RF electric power) such as a source RF signal and a bias RF signal to the at least one lower electrode and / or the at least one upper electrode. Thereby, a plasma can be formed from the 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 generation section 12. Further, by supplying the bias RF signal to the at least one lower electrode, a bias potential can be generated at the substrate W to introduce ion components in the formed plasma to the substrate W.

[0062] In one embodiment, the RF power source 31 includes a first RF generation section 31a and a second RF generation section 31b. The first RF generation section 31a is coupled to the at least one lower electrode and / or the at least one upper electrode via at least one impedance matching circuit, and is capable of generating a source RF signal (source RF electric power) for plasma generation. In one embodiment, the source RF signal has a frequency in a range of 10 MHz to 150 MHz. In one embodiment, it can be that the first RF generation section 31a is capable of generating a plurality of source RF signals having different frequencies. The generated one or more source RF signals are supplied to the at least one lower electrode and / or the at least one upper electrode.

[0063] The second RF generation section 31b is coupled to the at least one lower electrode via at least one impedance matching circuit, and is capable of generating a bias RF signal (bias RF electric power). The frequency of the bias RF signal can 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 a range of 100 kHz to 60 MHz. In one embodiment, it can be that the second RF generation section 31b is capable of generating a plurality of bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to the at least one lower electrode. Further, in various embodiments, at least one of the source RF signal and the bias RF signal can be pulsed.

[0064] Further, the power supply 30 can include a DC power source 32 coupled to the plasma processing chamber 10. The DC power source 32 includes a first DC generation section 32a and a second DC generation section 32b. In one embodiment, the first DC generation section 32a is connected to the at least one lower electrode, and is capable of generating a first DC signal. The generated first DC signal is applied to the at least one lower electrode. In one embodiment, the second DC generation section 32b is connected to the at least one upper electrode, and is capable of generating a second DC signal. The generated second DC signal is applied to the at least one upper electrode.

[0065] In various embodiments, the first DC signal and the second DC signal can be pulsed. In this case, a sequence of voltage pulses based on the DC is applied to the at least 1 lower electrode and / or the at least 1 upper electrode. The voltage pulses can have a pulse waveform of a shape of a rectangle, a trapezoid, a triangle, or a combination thereof. In one embodiment, a waveform generating section for generating a sequence of voltage pulses from the DC signal is connected between the first DC generating section 32a and the at least 1 lower electrode. Thus, the first DC generating section 32a and the waveform generating section constitute a voltage pulse generating section. In the case where the second DC generating section 32b and the waveform generating section constitute the voltage pulse generating section, the voltage pulse generating section is connected to the at least 1 upper electrode. The voltage pulses can have a positive polarity, or can have a negative polarity. Further, the sequence of voltage pulses can contain one or more positive polarity voltage pulses and one or more negative polarity voltage pulses in one cycle. In addition, it can be that the first DC generating section 32a and the second DC generating section 32b are provided in addition to the RF power source 31, or it can be that the first DC generating section 32a is provided instead of the second RF generating section 31b.

[0066] The exhaust system 40 can be connected to a gas exhaust port 10e provided at the bottom of the plasma processing chamber 10, for example. The exhaust system 40 can include a pressure regulating valve and a vacuum pump. The pressure within the plasma processing space 10s can be regulated with the pressure regulating valve. The vacuum pump can include a turbo molecular pump, a dry pump, or a combination thereof.

[0067] <Structure Example of Electrostatic Chuck>

[0068] Figure 3 FIG. 1 is a diagram showing a structure example of an electrostatic chuck 1111 according to the present embodiment. In one embodiment, the electrostatic chuck 1111 has a ceramic member 1111a as a dielectric member and an electrostatic electrode 1111b.

[0069] In one embodiment, the ceramic member 1111a has a first upper surface 200 and a seal band 201 as a ring-shaped protrusion provided outside the first upper surface 200. The seal band 201 has a height higher than that of the first upper surface 200. The seal band 201 can be integrally formed with other portions of the ceramic member 1111a including the first upper surface 200, or can be separately formed.

[0070] Figure 4is a drawing showing a structure example of the ceramic member 1111a when viewed from above. In one embodiment, the first upper surface 200 has a circular shape with the center of the ceramic member 1111a as the center. The seal band 201 has a circular ring shape with the center of the ceramic member 1111a as the center. By providing such a circular ring-shaped seal band 201, the substrate W electrostatically attracted contacts the upper surface of the seal band 201, and the heat transfer gas is prevented from leaking from the space between the back surface of the substrate W and the electrostatic chuck 1111 to the plasma processing space 10s.

[0071] In one embodiment, as shown in Figure 3 , the first upper surface 200 has a gas outflow portion 210 from which the heat transfer gas flows out. In one embodiment, the gas outflow portion 210 is connected to a heat transfer gas supply portion 212 through a gas flow path 211. The gas flow path 211 can pass through the inside of the substrate support portion 11. The heat transfer gas supply portion 212 can be provided outside the chamber 10. The gas outflow portion 210 can be configured one or more. The heat transfer gas can be a gas containing helium.

[0072] In one embodiment, a plurality of columnar convex portions 220 are provided on the first upper surface 200. In one embodiment, the convex portions 220 protrude upward with respect to the first upper surface 200. In one embodiment, the convex portions 220 have a cylindrical shape. In one embodiment, as shown in Figure 4 , the plurality of convex portions 220 can be provided at equal intervals along the circumferential direction around the center of the first upper surface 200. The plurality of convex portions 220 can be provided in a concentric circle shape or a radial shape with respect to the center of the first upper surface 200.

[0073] In one embodiment, as shown in Figure 3 , the seal band 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 on the outer side in the radial direction X of the inner peripheral portion 241. Figure 5 is a drawing showing a structure example of the seal band 201 after the peripheral portion of the seal band 201 is enlarged.

[0074] In one embodiment, the outer peripheral portion 240 has a flat second upper surface 250. In one embodiment, the outer peripheral portion 240 has a chamfered portion 251 at the outermost periphery of the upper surface.

[0075] In one embodiment, the inner peripheral portion 241 has only a flat third upper surface 260. That is, no protruding portion and recessed portion is provided on the upper surface of the inner peripheral portion 241. However, as described later, a protruding portion can also be provided on the upper surface of the inner peripheral portion 241.

[0076] The third upper surface 260 can 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 can be formed in a stepped shape that becomes higher in order toward the outside in the radial X direction. In order to secure a gap that allows the heat transfer gas to enter the space between the substrate W and the inner circumferential portion 241, 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. Therefore, it is preferable that the third upper surface 260 be lower than the second upper surface 250 by 0.1 μm or more.

[0077] The third upper surface 260 is higher than the first upper surface 200. Thereby, the distance between the substrate W and the third upper surface 260 becomes closer, and the electrostatic attraction to the substrate W can be increased in the inner circumferential portion 241. As a result, the electrostatic attraction to the substrate W of the seal band 201 can be secured. It is preferable that the third upper surface 260 be higher than the first upper surface 200 by 3 μm or more. Further, the difference ΔH in height between the third upper surface 260 and the second upper surface 250 (or the upper surface of the convex portion 220) is preferably within 7 μm. The third upper surface 260 can have a height H2 that is more than half of the height HI of the convex portion 220, with the first upper surface 200 as a reference. In addition, the distance LI in the vertical direction from the third upper surface 260 to the electrostatic electrode 1111b can be within the range of 100 μm to 750 μm.

[0078] A columnar or annular protruding portion can also be provided on the third upper surface 260. By providing a protruding portion 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 circumferential portion 241. However, when a protruding portion is provided on the third upper surface 260, there is a problem in that the contact pressure of the substrate W against the outer circumferential portion 240 becomes weak due to the contact of the upper surface of the protruding portion with the substrate W, and the heat transfer gas leaks. Therefore, it is preferable that no protruding portion be provided on the third upper surface 260, or that even if a protruding portion is provided, the upper surface of the protruding portion be lower than the second upper surface 250. Further, from the viewpoint of increasing the electrostatic attraction, it is preferable that the protruding portion be formed in an annular shape. However, when the protruding portion is formed in an annular shape, there is a problem in that the space between the protruding portion and the outer circumferential portion 240 is closed due to the deflection of the substrate, and the heat transfer gas cannot enter the space. Therefore, in the case where a protruding portion is formed, it is preferable that the protruding portion be formed in a columnar shape.

[0079] 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.

[0080] 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 portion 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 in the range of 1 mm to 36 mm.

[0081] 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.

[0082] The radial width D1 of the outer peripheral portion 240 can be in the range of 0.3 mm to 4 mm.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] <An example of a plasma processing method>

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] RF power source 31 supplies one or more RF signals to the upper electrode and / or the lower electrode. The atmosphere gas in the plasma processing space 10s is exhausted from the gas exhaust port 10e, and the inside of the plasma processing space 10s is reduced in pressure. Thus, plasma is generated on the substrate support portion 11 of the plasma processing space 10s, and the substrate W is subjected to etching processing. During the plasma processing, the heat transfer gas supplied to the back surface of the substrate W from the gas outflow portion 210 shown in FIG. 6 and the outer peripheral portion 240 of the seal band 201 cooled by the refrigerant cool the substrate W. Figure 3 The heat transfer gas supplied to the back surface of the substrate W from the gas outflow portion 210 shown in FIG. 6 and the outer peripheral portion 240 of the seal band 201 cooled by the refrigerant cool the substrate W.

[0093] With the present example embodiment, the ceramic member 1111a of the electrostatic chuck 1111 has the first upper surface 200 and the annular seal band 201 including the outer peripheral portion 240 and the inner peripheral portion 241 having a lower height than the outer peripheral portion 240, and the electrostatic electrode 1111b is disposed at least directly below the inner peripheral portion 241. Thus, a gap can be generated between the inner peripheral portion 241 of the seal band 201 and the substrate W, and the heat transfer gas reaches the gap on the inner peripheral portion 241, and the temperature adjustment of the substrate W by the heat transfer gas proceeds to the outer peripheral portion of the substrate W. Further, since the inner peripheral portion 241 of the seal band 201 is closer to the substrate W than the first upper surface 200, the electrostatic attraction of the substrate W by the inner peripheral portion 241 of the seal band 201 is greater than that by the central portion (the portion having the first upper surface 200). Therefore, the contact pressure (the adsorption force per unit area) of the substrate W to the outer peripheral portion 240 becomes large, and the substrate W is strongly adsorbed to the outer peripheral portion 240. As a result, the minute gap that can be generated between the substrate W and the outer peripheral portion 240 due to surface roughness or the like is reduced, the contact area of the substrate W to the outer peripheral portion 240 becomes large, and heat is efficiently transferred between the electrostatic chuck 1111 and the outer peripheral portion of the substrate W. As a result of the above, during the plasma processing, the outer peripheral portion of the substrate W can be sufficiently cooled, and the temperature uniformity of the substrate held by the electrostatic chuck 1111 can be improved.

[0094] <EMBODIMENT>

[0095] (1) As an example, regarding the case where the seal band 201 has the inner peripheral portion 241 lower than the outer peripheral portion 240 as in the present example embodiment, (2) as a comparative example, regarding the case where the seal band 201 has the inner peripheral portion 500 having the same height as the outer peripheral portion 240 as shown in FIG. 7, and (3) as a comparative example, regarding the case where the seal band 201 has the inner peripheral portion 600 having a higher height than the outer peripheral portion 240 as shown in FIG. 8, the temperature uniformity of the substrate W held by the electrostatic chuck 1111 was evaluated. Figure 6 Figure 7 ​The contact pressure of the sealing tape 201 to the substrate was compared in the case where the inner periphery 501 of the sealing tape 201 had the same height as the first upper surface 200 as shown. In addition, the width in the radial direction X of the outer periphery 240 was 1.7 mm, and the width in the radial direction X of the inner periphery 241 (500, 501) was 1.8 mm. Further, in (1), the difference ΔH in height between the third upper surface 260 and the second upper surface 250 was 5 μm. In the case of (2), the width in the radial direction of the outer periphery 240 of the sealing tape 201 was substantially larger than in the case of (1), and the contact area of the substrate W with the sealing tape 201 was larger. In the case of (3), the contact area of the substrate W with the sealing tape 201 was the same as in the case of (1), and the distance of the inner periphery 501 from the substrate W was larger. As a result of applying the same voltage to the electrostatic electrodes 1111b of (1) to (3), the contact pressure was 17.7 kPa in (1), 14.3 kPa in (2), and 16.0 kPa in (3). As a result, it was confirmed that heat was transferred between the substrate W and the sealing tape 201 in the case of (1) compared to the cases of (2) and (3). In fact, as a result of measuring the temperature of the outer periphery of the substrate W when the substrate W was cooled from the electrostatic chuck 1111 while the substrate W was held by the electrostatic chuck 1111, a low temperature effect of about 1.5 to 2.2°C was obtained in the case of (1) compared to the cases of (2) and (3).

[0096] In the above embodiment, the upper surface of the inner periphery 241 of the sealing tape 201 has only the third upper surface 260, but can also have an inclined surface. In one embodiment, as shown in FIG. 10, the upper surface of the inner periphery 241 of the sealing tape 201 has the third upper surface 260 and an inclined surface 310. Figure 9 As shown, the upper surface of the inner periphery 241 of the sealing tape 201 has the third upper surface 260 and the inclined surface 310. The inclined surface 310 can be connected to the third upper surface 260. 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, as shown in FIG. 11, the inclined surface 310 is connected at one end to the second upper surface 250 and at the other end to the third upper surface 260. Figure 10 As shown, the upper surface of the inner periphery 241 of the sealing tape 201 has the third upper surface 260 and the inclined surface 310. The inclined surface 310 can be connected to the third upper surface 260. 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, as shown in FIG. 11, the inclined surface 310 is connected at one end to the second upper surface 250 and at the other end to the third upper surface 260.

[0097] In one embodiment, as shown in FIG. 12, the upper surface of the inner periphery 241 of the sealing tape 201 is entirely the inclined surface 310. Figure 11 As shown, the upper surface of the inner periphery 241 of the sealing tape 201 has the third upper surface 260 and the inclined surface 310. The inclined surface 310 can be connected to the third upper surface 260. 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, as shown in FIG. 11, the inclined surface 310 is connected at one end to the second upper surface 250 and at the other end to the third upper surface 260.

[0098] In one embodiment, as shown in FIG. 12, the upper surface of the inner periphery 241 of the sealing tape 201 is entirely the inclined surface 310. Figure 12As shown, the inner peripheral portion 241 of the seal band 201 has an inclined upper surface 320 and a vertical surface 321 connected to each other in the radial direction X. The inclined upper surface 320 can 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 can be connected at one end to the inclined upper surface 320 and at the other end to the second upper surface 250.

[0099] In one embodiment, as shown in FIG. 1, the vertical surface 321 can be connected at one end to the first upper surface 200 and at the other end to the inclined upper surface 320. The inclined upper surface 320 can be connected at one end to the vertical surface 321 and at the other end to the second upper surface 250. Figure 13 As shown, the vertical surface 321 can be connected at one end to the first upper surface 200 and at the other end to the inclined upper surface 320. The inclined upper surface 320 can be connected at one end to the vertical surface 321 and at the other end to the second upper surface 250.

[0100] By having the inclined surface, as shown, compared to the case where only the flat third upper surface 260 is provided, the electrostatic attraction to the substrate W can be increased, and the substrate W can be strongly attracted to the outer peripheral portion 240. Figure 5

[0101] In the above embodiment, the electrostatic chuck 1111 is described as being used for a plasma device of the capacitively coupled type, but is not limited thereto and can be used for other types of plasma devices. In addition, the electrostatic chuck 1111 is not limited to a plasma processing device and can be used for other substrate processing devices.

[0102] Embodiments of the present application include the following modes.

[0103] (Postscript 1)

[0104] An electrostatic chuck that holds a substrate, comprising:

[0105] a dielectric member on which the substrate is placed; and

[0106] an electrostatic electrode disposed in the dielectric member,

[0107] the dielectric member includes:

[0108] a first upper surface having a gas outlet portion through which a gas flows; and

[0109] a seal band disposed outside the first upper surface and having a height higher than that of the first upper surface,

[0110] the seal band includes:

[0111] an outer peripheral portion; and

[0112] an inner peripheral portion having a height lower than that of the outer peripheral portion,

[0113] the electrostatic electrode is disposed at least directly below the inner peripheral portion of the seal band.​

[0114] (Paragraph 2)

[0115] The electrostatic chuck described in Paragraph 1, wherein

[0116] The outer peripheral portion of the seal band has a flat second upper surface,

[0117] The inner peripheral portion of the seal band has a flat third upper surface.

[0118] (Paragraph 3)

[0119] The electrostatic chuck described in Paragraph 2, wherein

[0120] The upper surface of the inner peripheral portion of the seal band further has an inclined surface.

[0121] (Paragraph 4)

[0122] The electrostatic chuck described in any one of Paragraphs 2 or 3, wherein

[0123] The third upper surface is lower than the second upper surface and higher than the first upper surface.

[0124] (Paragraph 5)

[0125] The electrostatic chuck described in any one of Paragraphs 2 to 4, wherein

[0126] The third upper surface is lower than the second upper surface by 0.1 μm or more.

[0127] (Paragraph 6)

[0128] The electrostatic chuck described in any one of Paragraphs 2 to 5, wherein

[0129] The third upper surface is higher than the first upper surface by 3 μm or more.

[0130] (Paragraph 7)

[0131] The electrostatic chuck described in any one of Paragraphs 2 to 6, wherein

[0132] The distance from the third upper surface to the electrostatic electrode is in the range of 100 μm to 750 μm.

[0133] (Paragraph 8)

[0134] The electrostatic chuck described in any one of Paragraphs 2 to 7, wherein

[0135] The upper surface of the inner peripheral portion of the seal band has only the third upper surface.

[0136] (Paragraph 9)

[0137] The electrostatic chuck according to any one of appendices 1 to 8, wherein

[0138] The dielectric member further has a plurality of convex portions arranged on the first upper surface and protruding upward with respect to the first upper surface.

[0139] (Appendix 10)

[0140] The electrostatic chuck according to appendix 9, wherein

[0141] The convex portions have a height that is the same as or lower than the outer peripheral portion of the sealing tape.

[0142] (Appendix 11)

[0143] The electrostatic chuck according to any one of appendices 9 to 10, wherein

[0144] The convex portions have a height in a range of 5 μm to 50 μm.

[0145] (Appendix 12)

[0146] The electrostatic chuck according to any one of appendices 9 to 11, wherein

[0147] The inner side end portion of the inner peripheral portion of the sealing tape is located between the outer side end portion of the convex portion located at the outermost side and the inner side end portion of the outer peripheral portion of the sealing tape.

[0148] (Appendix 13)

[0149] The electrostatic chuck according to any one of appendices 9 to 12, wherein

[0150] The inner side end portion of the inner peripheral portion of the sealing tape is located at a position that is inward of a radial intermediate point of the outer side end portion of the convex portion located at the outermost side and the inner side end portion of the outer peripheral portion of the sealing tape.

[0151] (Appendix 14)

[0152] The electrostatic chuck according to any one of appendices 9 to 13, wherein

[0153] The inner peripheral portion of the sealing tape has a height that is more than half the height of the convex portions.

[0154] (Appendix 15)

[0155] The electrostatic chuck according to any one of appendices 1 to 14, wherein

[0156] The electrostatic electrode is arranged from directly below the first upper surface to directly below the sealing tape,

[0157] The outer side end portion of the electrostatic electrode is located outward of a radially central position of the inner peripheral portion of the seal band.

[0158] (Paragraph 16)

[0159] The electrostatic chuck according to any one of Paragraphs 1 to 15, wherein

[0160] The outer side end portion of the electrostatic electrode is located directly below the outer peripheral portion of the seal band.

[0161] (Paragraph 17)

[0162] The electrostatic chuck according to any one of Paragraphs 1 to 16, wherein

[0163] The radially wide width of the outer peripheral portion of the seal band is in a range of 0.3 mm to 4 mm.

[0164] (Paragraph 18)

[0165] The electrostatic chuck according to any one of Paragraphs 1 to 17, wherein

[0166] The radially wide width of the inner peripheral portion of the seal band is in a range of 1 mm to 36 mm.

[0167] (Paragraph 19)

[0168] The electrostatic chuck according to any one of Paragraphs 1 to 18, wherein

[0169] The radially wide width of the inner peripheral portion of the seal band is greater than the radially wide width of the outer peripheral portion of the seal band.

[0170] (Paragraph 20)

[0171] The electrostatic chuck according to any one of Paragraphs 1 to 19, wherein

[0172] The upper surface of the inner peripheral portion of the seal band is an inclined surface as a whole.

[0173] (Paragraph 21)

[0174] The electrostatic chuck according to any one of Paragraphs 1 to 20, wherein

[0175] The inner peripheral portion of the seal band has an inclined upper surface and a vertical surface that are connected to each other in the radial direction.

[0176] (Paragraph 22)

[0177] The electrostatic chuck according to any one of Paragraphs 1 to 21, wherein

[0178] The thickness in the up-down direction of the dielectric member is in the range of 0.5 mm to 5 mm.

[0179] The above embodiments are described for the purpose of illustration and are not intended to limit the scope of the present application. The above embodiments can be variously modified without departing from the scope and spirit of the present application. For example, a part of the constitutional elements in one embodiment can be added to another embodiment. In addition, a part of the constitutional elements in one embodiment can be replaced with the corresponding constitutional elements of another embodiment.

[0180] Explanation of Reference Signs

[0181] 1: Plasma processing apparatus, 10: Chamber, 11: Substrate support section, 112: Ring assembly, 1111: Electrostatic chuck, 1111a: Ceramic member, 1111b: Electrostatic electrode, 200: First upper surface, 201: Sealing tape, 240: Outer peripheral section, 241: Inner peripheral section, 250: Second upper surface, 260: Third upper surface, W: Substrate.

Claims

1. An electrostatic chuck for holding a substrate, comprising: a dielectric member on which the substrate is placed; and an electrostatic electrode disposed in the dielectric member, the dielectric member including: a first upper surface having a gas outlet portion for gas to flow out; and a ring-shaped seal band disposed outside the first upper surface, having a height higher than that of the first upper surface, the seal band including: an outer peripheral portion; and an inner peripheral portion having a height lower than that of the outer peripheral portion, the electrostatic electrode being disposed at least directly below the inner peripheral portion of the seal band, the dielectric member further having a plurality of projections disposed on the first upper surface and protruding upward relative to the first upper surface, an inner side end portion of the inner peripheral portion of the seal band being located inward of a radial intermediate point between an outer side end portion of the projection located at an outermost side and an inner side end portion of the outer peripheral portion of the seal band.

2. The electrostatic chuck according to claim 1, wherein the outer peripheral portion of the seal band has a flat second upper surface, the inner peripheral portion of the seal band has a flat third upper surface.

3. The electrostatic chuck according to claim 2, wherein the upper surface of the inner peripheral portion of the seal band further has an inclined surface.

4. The electrostatic chuck according to 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 according to claim 4, wherein the third upper surface is lower than the second upper surface by 0.1 μm or more.

6. The electrostatic chuck according to claim 5, wherein the third upper surface is higher than the first upper surface by 3 μm or more.

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

8. The electrostatic chuck according to claim 2, wherein the upper surface of the inner peripheral portion of the seal band has only the third upper surface.

9. The electrostatic chuck according to claim 1, wherein the projections have a height which is the same as or lower than that of the outer peripheral portion of the seal band.

10. The electrostatic chuck according to claim 1, wherein the projections have a height in a range of 5 μm to 50 μm.

11. The electrostatic chuck according to claim 1, wherein the inner peripheral portion of the seal band has a height which is more than half of the height of the projections.

12. The electrostatic chuck according to claim 1, wherein a radial width of the outer peripheral portion of the seal band is in a range of 0.3 mm to 4 mm.

13. The electrostatic chuck according to claim 1, wherein a radial width of the inner peripheral portion of the seal band is in a range of 1 mm to 36 mm.

14. The electrostatic chuck according to claim 1, wherein the radial width of the inner peripheral portion of the seal band is greater than the radial width of the outer peripheral portion of the seal band.

15. The electrostatic chuck according to claim 1, wherein the upper surface of the inner peripheral portion of the seal band is an inclined surface as a whole. ​ 16. The electrostatic chuck of claim 1, wherein the inner circumferential portion of the seal band has an inclined upper surface and a vertical surface connected to each other in a radial direction.

17. The electrostatic chuck of claim 1, wherein the dielectric member has a thickness in a vertical direction in a range of 0.5 mm to 5 mm.

18. The electrostatic chuck of any one of claims 1 to 17, wherein 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 at a position outward of a radial center of the inner circumferential portion of the seal band.

19. The electrostatic chuck of claim 18, wherein the outer end portion of the electrostatic electrode is located directly below the outer circumferential portion of the seal band.

20. An electrostatic chuck that holds a substrate, comprising: a dielectric member that holds a substrate; and an electrostatic electrode disposed in the dielectric member, the dielectric member includes: a first upper surface having a gas outlet portion through which a gas is discharged; and a seal band that is annular, is disposed outward of the first upper surface, and has a height higher than the first upper surface, the seal band includes: an outer circumferential portion; and an inner circumferential portion that has a height lower than the outer circumferential portion, the electrostatic electrode is disposed at least directly below the inner circumferential portion of the seal band, a radial width of the inner circumferential portion of the seal band is greater than a radial width of the outer circumferential portion of the seal band.

21. The electrostatic chuck of claim 20, wherein the dielectric member further has a plurality of protrusions disposed above the first upper surface and protruding upward relative to the first upper surface, the inner circumferential portion of the seal band has a height that is more than half the height of the protrusions.

22. The electrostatic chuck of claim 20, wherein 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 at a position outward of a radial center of the inner circumferential portion of the seal band.

23. The electrostatic chuck of claim 22, wherein the outer end portion of the electrostatic electrode is located directly below the outer circumferential portion of the seal band.

24. The electrostatic chuck of any one of claims 20 to 23, wherein a radial width of the outer circumferential portion of the seal band is in a range of 0.3 mm to 4 mm.

25. The electrostatic chuck of claim 24, wherein a radial width of the inner circumferential portion of the seal band is in a range of 1 mm to 36 mm.

26. The electrostatic chuck of claim 20, wherein the inner circumferential portion of the seal band has an inclined upper surface and a vertical surface connected to each other in a radial direction.

27. An electrostatic chuck that holds a substrate, comprising: a dielectric member that holds a substrate; and an electrostatic electrode disposed in the dielectric member, the dielectric member includes: a first upper surface having a gas outlet portion through which a gas is discharged; and a seal band that is annular, is disposed outward of the first upper surface, and has a height higher than the first upper surface, the seal band includes: an outer circumferential portion; and an inner circumferential portion that has a height lower than the outer circumferential portion, the electrostatic electrode is disposed at least directly below the inner circumferential portion of the seal band, a radial width of the inner circumferential portion of the seal band is greater than a radial width of the outer circumferential portion of the seal band. A ring-shaped seal band is disposed outside the first upper surface and has a height higher than the first upper surface, The seal band 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 seal band, The outer peripheral portion of the seal band has a flat second upper surface, The inner peripheral portion of the seal band has a flat third upper surface.

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