Method of manufacturing electrostatic chuck

Abstract

To provide an electrostatic chuck and a manufacturing method of the electrostatic chuck, which reduce scratches generated on a rear surface of a substrate held by the electrostatic chuck.SOLUTION: The electrostatic chucks 1111 for holding the substrate W each include a dielectric (ceramic member 1111a), electrodes disposed inside the dielectric, and a gas outlet 300 through which a heat transfer gas flows out, wherein the dielectric includes an upper surface 200, a plurality of protrusions 201 protruding upward from the upper surface and supporting the substrate, and a seal band 202, and the protrusions each include a crystalline base and an amorphous surface layer disposed on the base. A method of manufacturing an electrostatic chuck includes a step of forming an amorphous surface layer, a step of polishing the surface layer to form a polished surface, and a polishing step of polishing the surface layer by blasting to form the polished surface. The blasting treatment may be performed using an elastic abrasive.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION Exemplary embodiments of the present disclosure relate to electrostatic chucks and methods for manufacturing electrostatic chucks. [Background technology]

[0002] Patent Document 1 describes a technique for providing an electrostatic chuck having a plurality of protrusions formed on its surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-129632 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique that can reduce scratches that occur on the back surface of a substrate held by an electrostatic chuck. [Means for solving the problem]

[0005] An electrostatic chuck in one exemplary embodiment of the present disclosure is an electrostatic chuck for holding a substrate, comprising: a dielectric; and an electrode disposed inside the dielectric, wherein the dielectric includes an upper surface and a plurality of protrusions protruding upward from the upper surface and configured to support the substrate, and the protrusions include a crystalline base and an amorphous surface layer disposed on the base. [Effects of the Invention]

[0006] According to one exemplary embodiment of the present disclosure, a technique can be provided that can reduce scratches that occur on the back surface of a substrate held by an electrostatic chuck. [Brief explanation of the drawings]

[0007] [Figure 1]FIG. 1 is a diagram illustrating an example of the configuration of a plasma processing system. [Figure 2] FIG. 1 is a diagram illustrating an example of the configuration of a plasma processing apparatus. [Figure 3] FIG. 2 is a plan view illustrating an example of the configuration of an electrostatic chuck. [Figure 4] 1A and 1B are diagrams for explaining a configuration example of an electrostatic chuck. [Figure 5] 10A and 10B are diagrams for explaining configuration examples of protrusions. [Figure 6] FIG. 10 is a diagram showing an example of the structure of the protrusion. [Figure 7] 1 is a flowchart showing an example of a method for manufacturing an electrostatic chuck. [Figure 8] 10A and 10B are diagrams illustrating an example of forming a polishing surface on the surface layer of a protrusion. [Figure 9] 10A and 10B are diagrams illustrating an example of forming polishing surfaces on the surface layers of the upper and side surfaces of the protrusions. [Figure 10] 10 is a flowchart showing another example of a method for manufacturing an electrostatic chuck. [Figure 11] 10A and 10B are diagrams illustrating an example in which the boundary between the surface layer and the base of the protrusion is exposed on the side surface. [Figure 12] FIG. 10 is a diagram illustrating an example of forming protrusions by blasting. [Figure 13] 10A and 10B are diagrams for explaining an example in which a protrusion is formed by laser processing and a surface layer is formed on the side surface of the protrusion at the same time or after the formation. [Figure 14] 10A and 10B are diagrams illustrating an example in which a surface layer is formed on the side surface of a protrusion and then a surface layer is formed on the top surface of the protrusion. [Figure 15] 10A and 10B are diagrams for explaining an example of forming a surface layer on a seal band. [Figure 16] 10A and 10B are diagrams illustrating an example of forming a surface layer on grooves arranged around a protrusion and a seal band. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, each embodiment of the present disclosure will be described.

[0009] In one exemplary embodiment, an electrostatic chuck for holding a substrate is provided, the electrostatic chuck comprising: a dielectric; and an electrode disposed within the dielectric, the dielectric including an upper surface and a plurality of protrusions projecting upward from the upper surface and configured to support the substrate, the protrusions including a crystalline base and an amorphous surface layer disposed on the base.

[0010] In one exemplary embodiment, the amorphous surface layer has a thickness in the range of 0.1 μm to 20 μm.

[0011] In one exemplary embodiment, the surface layer has a thermal conductivity that is the same as or less than the base.

[0012] In one exemplary embodiment, the non-crystalline surface layer comprises amorphous alumina.

[0013] In one exemplary embodiment, the plurality of protrusions comprises laser marks.

[0014] In one exemplary embodiment, a method for manufacturing an electrostatic chuck is provided, including: (a) forming a plurality of protrusions protruding upward from an upper surface of a dielectric, the protrusions being crystalline; and (b) irradiating the plurality of protrusions with laser light to form an amorphous surface layer on the protrusions.

[0015] In one exemplary embodiment, the amorphous surface layer is formed to a thickness in the range of 0.1 μm to 20 μm.

[0016] In one exemplary embodiment, the surface layer has a thermal conductivity that is equal to or less than that of the base of the protrusion.

[0017] In one exemplary embodiment, the non-crystalline surface layer comprises amorphous alumina.

[0018] In one exemplary embodiment, a method for manufacturing an electrostatic chuck is provided, the method including: (a) forming a plurality of protrusions protruding upward from an upper surface of a dielectric of an electrostatic chuck used in plasma processing, the protrusions being crystalline; and (b) irradiating the plurality of protrusions with laser light to form an amorphous surface layer on the protrusions.

[0019] In one exemplary embodiment, the amorphous surface layer is formed to a thickness in the range of 0.1 μm to 20 μm.

[0020] In one exemplary embodiment, the surface layer has a thermal conductivity that is equal to or less than that of the base of the protrusion.

[0021] In one exemplary embodiment, the non-crystalline surface layer comprises amorphous alumina.

[0022] In one exemplary embodiment, the surface layer has a polished surface with a surface roughness Ra of 0.05 μm or less.

[0023] In one exemplary embodiment, the protrusion has a top surface and a side surface, and the boundary between the crystalline base and the amorphous surface layer is not exposed on the top surface of the protrusion, but is exposed on the side surface of the protrusion.

[0024] In one exemplary embodiment, the surface layer is formed to a depth from the surface in the range of 100 nm to 500 nm, and has a hardness in the range of 22 GPa to 27 GPa as measured by a nanoindenter method.

[0025] In one exemplary embodiment, the protrusion comprises a seal band configured to support the periphery of the substrate.

[0026] In one exemplary embodiment, the dielectric further comprises a groove disposed around the protrusion, the groove including a crystalline groove base and an amorphous groove surface layer disposed on the groove base.

[0027] In one exemplary embodiment, the method further comprises the step of (c) polishing the amorphous surface layer.

[0028] In one exemplary embodiment, (a) a plurality of protrusions are formed by laser processing, (b) an amorphous surface layer is formed on the side surface of the protrusions by laser irradiation, and then an amorphous surface layer is formed on the top surface of the protrusions.

[0029] In one exemplary embodiment, (a) a plurality of protrusions are formed by blasting, and (b) an amorphous surface layer is formed on the upper surfaces of the protrusions by irradiating with a laser.

[0030] Hereinafter, each embodiment of the present disclosure will be described in detail with reference to the drawings. In each drawing, the same or similar elements are designated by the same reference numerals, and redundant explanations will be omitted. Unless otherwise specified, the positional relationships, such as up, down, left, and right, will be described based on the positional relationships shown in the drawings. The dimensional ratios in the drawings do not represent actual ratios, and the actual ratios are not limited to the ratios shown in the drawings.

[0031] <An example of a plasma processing system>

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

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

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

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

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

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

[0038] In one embodiment, the main body 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive member. The conductive member of the base 1110 can function as a lower electrode. The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic electrode 1111b disposed within the ceramic member 1111a. The ceramic member 1111a has a central region 111a. In one embodiment, the ceramic member 1111a also has an annular region 111b. Note that the annular region 111b may also be provided by another member surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member. In this case, the ring assembly 112 may be disposed on the annular electrostatic chuck or the annular insulating member, or may be disposed on both the electrostatic chuck 1111 and the annular insulating member. Furthermore, at least one RF / DC electrode coupled to an RF power supply 31 and / or a DC power supply 32, which will be described later, may be disposed within the ceramic member 1111a. In this case, the at least one RF / DC electrode functions as a lower electrode. When a bias RF signal and / or a DC signal, which will be described later, is supplied to the at least one RF / DC electrode, the RF / DC electrode is also called a bias electrode. Note that the conductive member of the base 1110 and the at least one RF / DC electrode may function as multiple lower electrodes. Alternatively, the electrostatic electrode 1111b may function as a lower electrode. Therefore, the substrate support 11 includes at least one lower electrode.

[0039] The ring assembly 112 includes one or more annular members. In one embodiment, the one or more annular members include one or more edge rings and at least one cover ring. The edge rings are formed of a conductive or insulating material, and the cover rings are formed of an insulating material.

[0040] The substrate support 11 may also include a temperature adjustment module configured to adjust at least one of the electrostatic chuck 1111, the ring assembly 112, and the substrate to a target temperature. The temperature adjustment module may include a heater, a heat transfer medium, a flow passage 1110a, or a combination thereof. A heat transfer fluid such as brine or a gas flows through the flow passage 1110a. In one embodiment, the flow passage 1110a is formed in the base 1110, and one or more heaters are disposed in the ceramic member 1111a of the electrostatic chuck 1111. The substrate support 11 may also include a heat transfer gas supply configured to supply a heat transfer gas to a gap between the backside of the substrate W and the central region 111a.

[0041] The showerhead 13 is configured to introduce at least one processing gas from the gas supply unit 20 into the plasma processing space 10s. The showerhead 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and multiple gas inlets 13c. The processing gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space 10s from the multiple gas inlets 13c. The showerhead 13 also includes at least one upper electrode. In addition to the showerhead 13, the gas introduction unit may also include one or more side gas injectors (SGIs) attached to one or more openings formed in the sidewall 10a.

[0042] 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 configured to supply at least one process gas from a corresponding gas source 21 to the showerhead 13 via a corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas supply unit 20 may include at least one flow modulation device that modulates or pulses the flow rate of the at least one process gas.

[0043] 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 configured to supply at least one RF signal (RF power) to at least one lower electrode and / or at least one upper electrode. This generates a plasma from at least one 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 the at least one lower electrode, a bias potential is generated on the substrate W, and ion components in the formed plasma can be attracted to the substrate W.

[0044] In one embodiment, the RF power supply 31 includes a first RF generating unit 31a and a second RF generating unit 31b. The first RF generating unit 31a is coupled to at least one lower electrode and / or at least one upper electrode via at least one impedance matching circuit and is configured to generate a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 10 MHz to 150 MHz. In one embodiment, the first RF generating unit 31a may be configured to generate multiple source RF signals having different frequencies. The generated one or more source RF signals are supplied to at least one lower electrode and / or at least one upper electrode.

[0045] The second RF generating unit 31b is coupled to at least one lower electrode via at least one impedance matching circuit and configured to generate a bias RF signal (bias RF power). The frequency of the bias RF signal may be the same as or different from the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency lower than the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 100 kHz to 60 MHz. In one embodiment, the second RF generating unit 31b may be configured to generate multiple bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to at least one lower electrode. In various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0046] The power supply 30 may also include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generator 32a and a second DC generator 32b. In one embodiment, the first DC generator 32a is connected to at least one lower electrode and configured to generate a first DC signal. The generated first DC signal is applied to the at least one lower electrode. In one embodiment, the second DC generator 32b is connected to at least one upper electrode and configured to generate a second DC signal. The generated second DC signal is applied to the at least one upper electrode.

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

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

[0049] <Example of electrostatic chuck configuration> 3 and 4 are diagrams illustrating an example of the configuration of the electrostatic chuck 1111 as viewed from above. Fig. 3 is a diagram illustrating an example of the electrostatic chuck 1111 as viewed from above. In one embodiment, the electrostatic chuck 1111 may include a ceramic member 1111a and an electrostatic electrode 1111b disposed within the ceramic member 1111a. The ceramic member 1111a may be an example of a dielectric material.

[0050] The ceramic member 1111a may have a generally cylindrical shape and may include an upper surface 200, a plurality of protrusions 201, and a seal band 202.

[0051] The upper surface 200 may be a circular horizontal surface and may have a center on the central axis of the ceramic member 1111a.

[0052] The multiple protrusions 201 may be configured to support the back surface of the substrate W when the substrate is electrostatically attracted to the electrostatic chuck 1111. The multiple protrusions 201 may be arranged on the upper surface 200. Each protrusion 201 may protrude upward from the upper surface 200. Each protrusion 201 may have a substantially hemispherical shape with the highest point at the center. The protrusions 201 may be integral with the upper surface 200 or may be separate from the upper surface 200. The protrusions 201 may be made of a different material from that of the upper surface 200.

[0053] The protrusions 201 may have a height in the range of 5 μm to 50 μm, and a width (outer diameter) in the range of 0.1 mm to 3 mm.

[0054] The multiple protrusions 201 may be arranged at intervals (pitch) within a range of 3 mm or more and 30 mm or less. The multiple protrusions 201 may be evenly arranged on the upper surface 200. The multiple protrusions 201 may be arranged concentrically, radially, or in a grid pattern relative to the center of the upper surface 200.

[0055] Fig. 5 is a diagram illustrating an example of the configuration of the protrusion 201. Fig. 6 is a diagram illustrating an example of the structure of the protrusion 201. The protrusion 201 may have a crystalline base 250 and an amorphous surface layer 251 disposed on the base 250.

[0056] The base 250 may be made of crystalline alumina (Al2O3). The crystal grains of the base 250 may have an average grain size in the range of 0.5 μm to 30 μm, preferably 2 μm to 15 μm. The average grain size can be calculated by assuming that the crystal grains are circular, dividing a specific area A by the number of grains B present within that area A to obtain the area C per circular grain (=A / B), and then calculating the diameter D of the circular grain from that area C.

[0057] The surface layer 251 may be made of amorphous alumina. The surface layer 251 may have a thickness in the range of 0.1 μm to 20 μm. The surface layer 251 may be a laser-processed layer formed by irradiating with laser light. The surface layer 251 may have laser irradiation marks. The laser irradiation marks may be formed by melting with laser light and then solidifying. The surface layer 251 may have a region near the base 250 where amorphous and crystalline materials are mixed.

[0058] The surface layer 251 of the protrusion 201 may have the same or a lower thermal conductivity than the base 250 .

[0059] 3 and 4, the seal band 202 may protrude upward from the upper surface 200 and be arranged in a ring shape around the outer periphery of the upper surface 200. The seal band 202 may be configured to come into contact with the rear surface of the outer periphery of the substrate W when the substrate is electrostatically attracted to the electrostatic chuck 1111. The seal band 202 may have the same height as the protrusion 201, or may have a height greater than or smaller than the protrusion 201. The seal band 202 may be an example of a protrusion. That is, the seal band 202 may have a base 250 and a surface layer 251, similar to the protrusion 201.

[0060] A gas outlet 300 through which a heat transfer gas flows out may be formed on the upper surface 200. As shown in FIG. 4, the gas outlet 300 may be connected to a heat transfer gas supply unit 302 through a gas passage 301. The gas passage 301 may pass through the inside of the substrate support 11. The heat transfer gas supply unit 302 may be provided outside the chamber 10. One or more gas outlets 300 may be arranged. The heat transfer gas may include helium gas.

[0061] The electrostatic electrode 1111b may be connected to a direct current (DC) power supply 311 via a switch 310. When a DC voltage from the DC power supply 311 is applied to the electrostatic electrode 1111b, an electrostatic attractive force (Coulomb force) may be generated between the ceramic member 1111a and the substrate W. The substrate W may be attracted to the ceramic member 1111a by the electrostatic attractive force and may be adsorbed and held on the ceramic member 1111a.

[0062] <An example of a manufacturing method for an electrostatic chuck> 7 is a flowchart showing an example of a method for manufacturing an electrostatic chuck (hereinafter also referred to as the present manufacturing method). The present manufacturing method may include step ST1 of forming a plurality of protrusions protruding upward from the upper surface 200 of the ceramic member 1111a, and step ST2 of irradiating the plurality of protrusions with a laser beam to form amorphous surface layers on the plurality of protrusions.

[0063] In step ST1, the plurality of protrusions may be formed by machining and / or laser processing the surface of the ceramic member 1111a. Alternatively, the plurality of protrusions may be formed by adhering pre-formed protrusions to the surface of the ceramic member 1111a. The ceramic member 1111a may be a ceramic member of a so-called used electrostatic chuck that has been used in the plasma processing apparatus 1. The ceramic member 1111a may be a ceramic member of an electrostatic chuck that has been removed from the plasma processing apparatus 1. This manufacturing method may include a step of removing the used electrostatic chuck from the plasma processing apparatus 1. When laser processing is used, the plurality of protrusions may be formed by using laser light to remove a portion of the upper surface of the ceramic member 1111a, for example, an area where no protrusions are to be formed.

[0064] In step ST2, the light source of the laser light may be ultraviolet light or infrared light. The amorphous surface layer 251 may be formed to a thickness in the range of 0.1 μm to 20 μm. The amorphous surface layer 251 may be formed to a thickness in the range of 0.1 μm to 10 μm. The amorphous surface layer 251 may contain plasma-resistant ceramics. The amorphous surface layer 251 may contain amorphous alumina.

[0065] <An example of a plasma processing method> The plasma processing method performed in the plasma processing apparatus 1 includes an etching process that uses plasma to etch a film on the substrate W. In one embodiment, the plasma processing method is executed by the control unit 2 in the plasma processing apparatus 1.

[0066] First, as shown in Fig. 2, the substrate W is carried into the chamber 10 and placed on the substrate support 11. The substrate W is attracted and held by the electrostatic chuck 1111 as shown in Fig. 4. At this time, the substrate W is placed on the ceramic member 1111a, and the back surface of the substrate W contacts the protrusions 201 and the seal band 202. A DC voltage is applied to the electrostatic electrode 1111b, generating an electrostatic attractive force between the electrostatic chuck 1111 and the substrate W, and the substrate W is attracted to the electrostatic chuck 1111.

[0067] In the substrate support part 11 shown in FIG. 2, a coolant is supplied to the flow path 1110a, and the temperatures of the electrostatic chuck 1111 and the substrate W held by the electrostatic chuck 1111 are adjusted to a predetermined temperature.

[0068] 4 is supplied to the gas outlet 300, and the heat transfer gas is supplied from the gas outlet 300 to the space formed between the substrate W and the upper surface 200. The heat transfer gas controls the temperature of the substrate W from its back surface side.

[0069] 2 to the shower head 13, and then supplied to the plasma processing space 10s from the shower head 13. The processing gas supplied at this time includes a gas that generates active species necessary for etching the substrate W.

[0070] One or more RF signals are supplied to the upper electrode and / or the lower electrode from the RF power supply 31. The atmosphere in the plasma processing space 10s is exhausted through the gas exhaust port 10e, and the pressure inside the plasma processing space 10s may be reduced. In this way, plasma is generated on the substrate support 11 in the plasma processing space 10s, and the substrate W is etched.

[0071] According to this exemplary embodiment, the ceramic member 1111a of the electrostatic chuck 1111 includes an upper surface 200 and a plurality of protrusions 201 that protrude upward from the upper surface 200 and are configured to support the substrate W, and the protrusions 201 include a crystalline base 250 and an amorphous surface layer 251 that is disposed on the base 250. This can reduce scratches on the back surface of the substrate W held by the electrostatic chuck 1111.

[0072] When a crystalline protrusion slides against the backside of the substrate W under strong surface pressure, the stress concentrates at the grain boundaries of the protrusion, causing the crystal particles to peel off and / or detach. These crystal particles, and the sharp edges formed on the surface of the substrate support by the detached crystal particles, can scratch the backside of the substrate W. By forming an amorphous surface layer 251 on the protrusion 201 as in this exemplary embodiment, the peeling and detachment of crystal particles can be suppressed, thereby preventing scratches on the backside of the substrate W due to contact with the protrusion. Additionally, when the surface layer 251 of the protrusion 201 is scraped, extremely fine sub-nanosized particles are generated, which function similarly to lubricating particles. This reduces the coefficient of friction between the substrate W and the protrusion 201, thereby preventing scratches on the backside of the substrate W. Furthermore, by suppressing the peeling and detachment of crystal particles, particle generation can be suppressed.

[0073] <Example> The surface of crystalline alumina was irradiated with laser light, and the surface was imaged using an electron backscattering spectroscopy (EBDS). Fig. 6 is a schematic diagram showing an example of the structure of alumina imaged using the electron backscattering spectroscopy (EBDS). As shown in Fig. 6, by irradiating the laser light, amorphous alumina (surface layer 251) (without crystal particles) was formed on crystalline alumina (base 250) (with crystal particles).

[0074] Scratch tests were conducted on crystalline alumina and amorphous alumina. The scratch tests were carried out as follows: the indenter (R = 200 μm) of the scratch tester was brought into contact with the test piece and moved in one direction while increasing the contact load, and images were taken of the process. The load was continuously increased from 0 N to 40 N. The surface pressure applied to the test piece was calculated from the width of the indenter's friction against the test piece and the indenter load, and the surface conditions of the crystalline and amorphous alumina under the same surface pressure were observed.

[0075] For the crystalline alumina, detached crystal particles and many small particles broken into sharp angles were observed, whereas for the amorphous alumina, no detached particles or broken particles were observed on the surface.

[0076] In the above embodiment, the electrostatic chuck 1111 is used in a capacitively coupled plasma apparatus, but the present invention is not limited to this and may be used in other types of plasma apparatus. Furthermore, the electrostatic chuck 1111 is not limited to plasma processing apparatuses and may be used in other substrate processing apparatuses.

[0077] In the above embodiment, as shown in FIG. 8, the surface layer 251 of the protrusion 201 may have a polished surface 400 with a surface roughness Ra of 0.05 μm or less. The protrusion 201 may have a cylindrical shape. The amorphous surface layer 251 may be formed on the upper surface 201a of the protrusion 201. As shown in FIG. 9, the surface layer 251 and its polished surface 400 may be formed on the upper surface 201a and side surface 201b of the protrusion 201. Furthermore, the amorphous surface layer 251 and its polished surface 400 may also be formed on the upper surface 200 of the ceramic member 1111a.

[0078] In this case, as shown in FIG. 10 , the manufacturing method of the electrostatic chuck may include step ST3 of polishing the surface layer 251 after step ST2 of forming the amorphous surface layer. This step ST3 forms a polished surface 400. In step ST3, the surface layer 251 may be polished by blasting to form the polished surface 400. The blasting may be performed using an elastic abrasive. According to this embodiment, unevenness of the surface layer 251 that may be caused by laser processing can be flattened. This can suppress fluctuations in the contact area of ​​the substrate supported by the protrusions 201, which can cause temperature fluctuations of the substrate, and suppress dust generation from the surface layer due to friction of the substrate or plasma irradiation.

[0079] In the above embodiment, the boundary B1 between the crystalline base 250 and the amorphous surface layer 251 may be exposed on the side surface 201b of the protrusion 201, rather than on the upper surface 201a of the protrusion 201, as shown in FIG.

[0080] In this case, in step ST1 of forming a plurality of protrusions in the method of manufacturing an electrostatic chuck, a plurality of protrusions 201 are formed by blasting as shown in Fig. 12. Thereafter, in step ST2 of forming an amorphous surface layer, laser light is irradiated onto upper surfaces 201a of protrusions 201. As a result, an amorphous surface layer 251 is formed on upper surfaces 201a of protrusions 201 as shown in Fig. 11.

[0081] Furthermore, in the method for manufacturing an electrostatic chuck described above, in step ST1 of forming a plurality of protrusions, the plurality of protrusions 201 may be formed by laser processing. At that time, or thereafter, in step ST2 of forming an amorphous surface layer, laser light is irradiated onto the protrusions 201. As a result, an amorphous surface layer 251 is formed on the side surface 201b of each protrusion 201, as shown in FIG. 13 . At this time, a boundary B1 between the crystalline base 250 and the amorphous surface layer 251 is exposed on the upper surface 201a. Thereafter, laser light is irradiated onto the upper surface 201a of each protrusion 201. As a result, as shown in FIG. 14 , the boundary B1 between the crystalline base 250 and the amorphous surface layer 251 is exposed on the side surface 201b of each protrusion 201, not on the upper surface 201a of each protrusion 201. In this case, the boundary B1 becomes a crack interface, which can prevent particles detached from the crack interface from adhering to the substrate and preventing scratches on the rear surface of the substrate.

[0082] In the above embodiment, the surface layer 251 may be formed to a depth from the surface in the range of 100 nm to 500 nm, and have a hardness (nanoindenter value) measured by a nanoindenter method in the range of 22 GPa to 27 GPa. The nanoindenter value of the surface layer 251 may be greater than that of single crystal silicon and less than that of alumina ceramic.

[0083] 15 , the seal band 202 may have a crystalline base 250 and an amorphous surface layer 251, similar to the protrusion 201. The amorphous surface layer 251 may be formed on the upper surface of the seal band 202, or may be formed on the upper surface and side surfaces of the seal band 202.

[0084] 16, the ceramic member 1111a may further include a groove 450 arranged around the protrusion 201 and the seal band 202. The groove 450 may be arranged in an annular shape so as to surround the protrusion 201. The groove 450 may also be arranged in an annular shape inside the annular seal band 202. The groove 450 may have a crystalline groove base 460 and an amorphous groove surface layer 461 arranged on the groove base 460. The groove surface layer 461 may be formed by laser irradiation, similar to the protrusion 201.

[0085] Embodiments of the present disclosure further include the following aspects.

[0086] (Appendix 1) An electrostatic chuck for holding a substrate, a dielectric; an electrode disposed inside the dielectric; The dielectric material is The top surface and a plurality of protrusions projecting upward from the upper surface and configured to support a substrate; The protrusion includes a crystalline base and an amorphous surface layer disposed on the base.

[0087] (Appendix 2) 2. The electrostatic chuck of claim 1, wherein the amorphous surface layer has a thickness in the range of 0.1 μm to 20 μm.

[0088] (Appendix 3) 3. The electrostatic chuck of claim 1, wherein the surface layer has a thermal conductivity equal to or lower than that of the base.

[0089] (Appendix 4) 4. The electrostatic chuck of claim 1, wherein the non-crystalline surface layer comprises amorphous alumina.

[0090] (Appendix 5) 5. The electrostatic chuck according to claim 1, wherein the plurality of protrusions have laser irradiation marks.

[0091] (Appendix 6) (a) forming a plurality of protrusions protruding upward from an upper surface of a dielectric material, the protrusions being crystalline; (b) irradiating the plurality of protrusions with laser light to form amorphous surface layers on the protrusions.

[0092] (Appendix 7) 7. The method for manufacturing an electrostatic chuck according to claim 6, wherein the amorphous surface layer is formed to a thickness in the range of 0.1 μm to 20 μm.

[0093] (Appendix 8) 8. The method for manufacturing an electrostatic chuck according to claim 6, wherein the surface layer has a lower thermal conductivity than a base portion of the protrusion.

[0094] (Appendix 9) 9. The method for manufacturing an electrostatic chuck according to claim 6, wherein the non-crystalline surface layer contains amorphous alumina.

[0095] (Appendix 10) (a) forming a plurality of protrusions on an upper surface of a dielectric body of a (used) electrostatic chuck that has been used in plasma processing, the protrusions being crystalline; (b) irradiating the plurality of protrusions with laser light to form amorphous surface layers on the protrusions.

[0096] (Appendix 11) 11. The method for manufacturing an electrostatic chuck according to claim 10, wherein the amorphous surface layer is formed to a thickness in the range of 0.1 μm to 20 μm.

[0097] (Appendix 12) 12. The method for manufacturing an electrostatic chuck according to claim 10, wherein the surface layer has a thermal conductivity equal to or lower than that of a base portion of the protrusion.

[0098] (Appendix 13) 13. The method for manufacturing an electrostatic chuck according to any one of claims 10 to 12, wherein the non-crystalline surface layer comprises amorphous alumina.

[0099] (Appendix 14) The surface layer has a polished surface with a surface roughness Ra of 0.05 μm or less. 6. The electrostatic chuck of claim 1.

[0100] (Appendix 15) The protrusion has an upper surface and a side surface, the boundary between the crystalline base and the amorphous surface layer is not exposed on the top surface of the protrusion, but is exposed on the side surface of the protrusion. 15. The electrostatic chuck of claim 1.

[0101] (Appendix 16) The surface layer is formed to a depth of 100 nm to 500 nm from the surface and has a hardness measured by a nanoindenter method of 22 GPa to 27 GPa. 16. The electrostatic chuck of any one of appendixes 1 to 5, 14, and 15.

[0102] (Appendix 17) the protrusion includes a seal band configured to support the outer periphery of the substrate; 17. The electrostatic chuck of any one of appendixes 1 to 5, 14 to 16.

[0103] (Appendix 18) the dielectric further includes a groove disposed around the protrusion; the groove includes a crystalline groove base and an amorphous groove surface layer disposed on the groove base. 18. The electrostatic chuck of any one of appendixes 1 to 5, 14 to 17.

[0104] (Appendix 19) (c) further comprising the step of polishing the amorphous surface layer; 14. A method for manufacturing an electrostatic chuck according to any one of claims 6 to 13.

[0105] (Appendix 20) In the step (a), the plurality of protrusions are formed by laser processing; In the step (b), the amorphous surface layer is formed on the side surface of the protrusion by laser irradiation, and then the amorphous surface layer is formed on the top surface of the protrusion. A method for manufacturing an electrostatic chuck according to any one of appendixes 6 to 13 and 19.

[0106] (Appendix 21) In the step (a), the plurality of protrusions are formed by blasting; In the step (b), the amorphous surface layer is formed on the upper surface of the protrusion by laser irradiation. A method for manufacturing an electrostatic chuck according to any one of appendixes 6 to 13 and 19.

[0107] The above embodiments are described for the purpose of explanation and are not intended to limit the scope of the present disclosure. Various modifications can be made to the above embodiments without departing from the scope and spirit of the present disclosure. For example, some components in one embodiment can be added to other embodiments. Also, some components in one embodiment can be replaced with corresponding components in other embodiments. [Explanation of symbols]

[0108] 1: Plasma processing apparatus, 10: Chamber, 11: Substrate support, 1111: Electrostatic chuck, 1111a: Ceramic member, 1111b: Electrostatic electrode, 200: Upper surface, 201: Protrusion, 202: Seal band, 250: Base, 251: Surface layer, W: Substrate

Claims

1. (a) forming a protrusion that protrudes upward from an upper surface of a dielectric; (b) irradiating the protrusions with laser light to form a surface layer containing amorphous alumina on the protrusions, A method for manufacturing an electrostatic chuck.

2. (a) forming a protrusion on an upper surface of a dielectric body of an electrostatic chuck used in plasma processing, the protrusion protruding upward from the upper surface; (b) irradiating the protrusions with laser light to form a surface layer containing amorphous alumina on the protrusions, A method for manufacturing an electrostatic chuck.

3. (a) forming a protrusion that protrudes upward from an upper surface of a dielectric; (b) irradiating the protrusions with laser light to form an amorphous surface layer on the protrusions; (c) polishing the amorphous surface layer; A method for manufacturing an electrostatic chuck.

4. The protrusions include crystalline alumina. The method for manufacturing the electrostatic chuck according to any one of claims 1 to 3.

5. (c) polishing the amorphous surface layer; The method for manufacturing an electrostatic chuck according to claim 1 or 2.

6. (c) is carried out using an elastic abrasive material; The method for manufacturing an electrostatic chuck according to claim 3 .

7. In (a), the protrusion is formed by laser processing. The method for manufacturing the electrostatic chuck according to any one of claims 1 to 3.

8. In (a), the protrusions are formed by blasting. The method for manufacturing the electrostatic chuck according to any one of claims 1 to 3.

9. 4. The method for manufacturing an electrostatic chuck according to claim 1, wherein the amorphous surface layer is formed to a thickness in the range of 0.1 μm to 20 μm.

10. The surface layer has a lower thermal conductivity than the base portion of the protrusion. The method for manufacturing the electrostatic chuck according to any one of claims 1 to 3.

11. In the step (b), the amorphous surface layer is formed on the side surface of the protrusion by laser irradiation, and then the amorphous surface layer is formed on the upper surface of the protrusion. The method for manufacturing the electrostatic chuck according to any one of claims 1 to 3.

12. the amorphous surface layer comprises amorphous alumina; The method for manufacturing an electrostatic chuck according to claim 3 .

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