Plasma processing device

Abstract

Provided is a plasma processing device (1) comprising: a first member (13A) configured from a material having a crystal orientation; a second member (13B); and a fastening member (13C) having a contact portion (13Ca) that contacts a portion of the entire circumference of the first member (13A) and serving to fasten the first member (13A) to the second member (13B). A first direction (Dt) in which the first member (13A) expands and contracts due to a rise and a decrease in temperature at the portion where the contact portion (13Ca) contacts the first member (13A) is different from a second direction (Dc1) of the crystal orientation of the first member at said portion.

Description

Plasma processing equipment

[0001] The present disclosure relates to a plasma processing apparatus.

[0002] For example, Patent Document 1 discloses an etching apparatus having a ceiling electrode plate, a cooling plate having a cooling mechanism for cooling the ceiling electrode plate, and a clamp for supporting the ceiling electrode plate on the cooling plate on the outer periphery of the cooling plate.

[0003] JP 2016-129176 A

[0004] The present disclosure provides a technique for suppressing breakage in a component made of a material having a crystal orientation.

[0005] According to one aspect of the present disclosure, there is provided a plasma processing apparatus comprising: a first member made of a material having a crystal orientation; a second member; and a fastening member having a contact portion that contacts a portion of the entire circumference of the first member and fastens the first member to the second member, wherein a first direction in which the first member expands and contracts due to an increase and decrease in temperature at a portion of the first member where the contact portion contacts is different from a second direction of the crystal orientation of the first member at the portion.

[0006] The present disclosure provides a technique for suppressing breakage in a component made of a material having a crystal orientation.

[0007] FIG. 1 is a diagram illustrating the configuration of a plasma processing system including a plasma processing apparatus according to this embodiment. FIG. 2 is a diagram illustrating a holding structure for a ceiling electrode plate in the plasma processing apparatus according to this embodiment. FIG. 3 is a diagram illustrating the relationship between the crystal orientation and the expansion / contraction direction of the ceiling electrode plate in the plasma processing apparatus according to this embodiment. FIG. 4 is a diagram illustrating a holding structure for a ceiling electrode plate in a modified example of the plasma processing apparatus according to this embodiment. FIG. 5 is a diagram illustrating the relationship between the crystal orientation and the expansion / contraction direction of the ceiling electrode plate in a modified example of the plasma processing apparatus according to this embodiment. FIG. 6 is a diagram illustrating a holding structure for a ceiling electrode plate in the plasma processing apparatus according to this embodiment.

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In this specification and the drawings, substantially identical components are designated by the same reference numerals, and redundant description will be omitted. To facilitate understanding, the scale of each part in the drawings may differ from the actual scale. Directions such as parallel, right-angled, orthogonal, horizontal, vertical, up / down, left / right, and the like are permitted to a degree that does not impair the effects of the embodiments. The shape of corners is not limited to right angles and may be rounded. Parallel, right-angled, orthogonal, horizontal, and vertical may include approximately parallel, approximately right-angled, approximately orthogonal, approximately horizontal, and approximately vertical.

[0009] <Plasma Processing System> An example of the configuration of a plasma processing system will be described below. Fig. 1 is a diagram illustrating the configuration of a plasma processing system including a plasma processing apparatus 1, which is an example of a plasma processing apparatus according to this embodiment.

[0010] The plasma processing system includes a capacitively coupled plasma processing apparatus 1 and a controller 2. 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 has at least one gas inlet for supplying at least one processing gas to the plasma processing space 10s and at least one gas outlet for exhausting gas from the plasma processing space 10s. The sidewall 10a is grounded. The showerhead 13 and the substrate support 11 are electrically insulated from the plasma processing chamber 10 housing.

[0011] The substrate support 11 includes a main body 111 and a ring assembly 112. The main body 111 has a central region (substrate support surface) 111a for supporting a substrate (wafer) W and an annular region (ring support surface) 111b for supporting the ring assembly 112. 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. In one embodiment, the main body 111 includes a base and an electrostatic chuck. The base includes a conductive member. The conductive member of the base functions as a lower electrode. The electrostatic chuck is disposed on the base. The upper surface of the electrostatic chuck has the substrate support surface 111a. The ring assembly 112 includes one or more annular members. At least one of the one or more annular members is an edge ring. Although not shown, the substrate support 11 may also include a temperature control module configured to adjust at least one of the electrostatic chuck, the ring assembly 112, and the substrate to a target temperature. The temperature control module may include a heater, a heat transfer medium, a flow path, or a combination thereof. A heat transfer fluid such as brine or gas flows through the flow path. The substrate support 11 may also include a heat transfer gas supply unit configured to supply a heat transfer gas between the back surface of the substrate W and the substrate support surface 111 a.

[0012] 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 includes a ceiling electrode plate 13A, a cooling plate 13B, and a clamp 13C. The showerhead 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and multiple gas inlets 13c. The gas diffusion chamber 13b and the gas inlets 13c are provided in the ceiling electrode plate 13A. 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 through the multiple gas inlets 13c. The cooling plate 13B has a flow path through which a heat transfer fluid (not shown) flows. The cooling plate 13B cools the ceiling electrode plate 13A. The showerhead 13 also includes a conductive member. The conductive member of the showerhead 13 functions as an upper electrode. In addition to the shower head 13, the gas introduction part may include one or more side gas injectors (SGIs) attached to one or more openings formed in the side wall 10a.

[0013] 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 one or more flow modulation devices to modulate or pulse the flow rate of the at least one process gas.

[0014] 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), such as a source RF signal and a bias RF signal, to the conductive member of the substrate support 11 and / or the conductive member of the showerhead 13. This causes plasma to be formed from at least one process gas supplied to the plasma processing space 10s. Therefore, the RF power supply 31 can function as at least a part of a plasma generating unit configured to generate plasma from one or more process gases in the plasma processing chamber 10. Furthermore, by supplying a bias RF signal to the conductive member of the substrate support 11, a bias potential is generated on the substrate W, thereby attracting ion components in the formed plasma to the substrate W.

[0015] In one embodiment, the RF power supply 31 includes a first RF generator 31a and a second RF generator 31b. The first RF generator 31a is coupled to the conductive members of the substrate support 11 and / or the conductive members of the showerhead 13 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 13 MHz to 150 MHz. In one embodiment, the first RF generator 31a may be configured to generate multiple source RF signals having different frequencies. The generated one or more source RF signals are supplied to the conductive members of the substrate support 11 and / or the conductive members of the showerhead 13. The second RF generator 31b is coupled to the conductive members of the substrate support 11 via at least one impedance matching circuit and is configured to generate a bias RF signal (bias RF power). In one embodiment, the bias RF signal has a frequency lower than that of the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 400 kHz to 13.56 MHz. In one embodiment, the second RF generator 31b may be configured to generate multiple bias RF signals having different frequencies, and the generated bias RF signals or signals may be supplied to the conductive members of the substrate support 11. Also, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0016] 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 a conductive member of the substrate support 11 and configured to generate a first DC signal. The generated first bias DC signal is applied to the conductive member of the substrate support 11. In one embodiment, the first DC signal may be applied to another electrode, such as an electrode in an electrostatic chuck. In one embodiment, the second DC generator 32b is connected to a conductive member of the showerhead 13 and configured to generate a second DC signal. The generated second DC signal is applied to the conductive member of the showerhead 13. In various embodiments, at least one of the first and second DC signals may be pulsed. 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.

[0017] The exhaust system 40 may be connected to, for example, a gas exhaust port 10e provided at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure in the plasma processing space 10s is regulated by the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0018] The controller 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform the various processes described in this disclosure. The controller 2 may be configured to control each element of the plasma processing apparatus 1 to perform the various processes described herein. In one embodiment, part or all of the controller 2 may be included in the plasma processing apparatus 1. The controller 2 may include, for example, a computer 2a. The computer 2a may include, for example, a processing unit (CPU: Central Processing Unit) 2a1, a storage unit 2a2, and a communication interface 2a3. The processing unit 2a1 may be configured to perform various control operations based on programs stored in the storage unit 2a2. 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 LAN (Local Area Network).

[0019] The plasma processing apparatus according to this embodiment includes a first member made of a material having a crystal orientation, a second member, and a fastening member having a contact portion that contacts a portion of the entire circumference of the first member and fastens the first member to the second member. In the plasma processing apparatus according to this embodiment, a first direction in which the first member expands and contracts due to a rise and fall in temperature at a portion of the first member where the contact portion contacts differs from a second direction of the crystal orientation of the first member at that portion.

[0020] The plasma processing apparatus according to this embodiment will be described using a specific example. Fig. 2 is a diagram illustrating a holding structure of the ceiling electrode plate 13A in the plasma processing apparatus 1, which is an example of the plasma processing apparatus according to this embodiment. Fig. 2 is a diagram illustrating the shower head 13 as viewed from below.

[0021] In the plasma processing apparatus 1, the ceiling electrode plate 13A is an example of a first member made of a material having a crystal orientation, the cooling plate 13B is an example of a second member, and the clamp 13C is an example of a fastening member. Note that the first member, second member, and third member are not limited to the above examples.

[0022] The ceiling electrode plate 13A is formed of, for example, single crystal silicon. Single crystal silicon is an example of a material having a crystal orientation. In other words, the ceiling electrode plate 13A is an example of a first member made of a material having a crystal orientation.

[0023] Single crystal silicon is a so-called brittle material. A brittle material is a material that has the property of breaking before it is significantly deformed when subjected to an external force. In other words, single crystal silicon, which is a brittle material, breaks suddenly when a crack occurs in the material. Single crystal silicon also has a crystal orientation. If scratches occur in single crystal silicon in the direction of the crystal orientation, the single crystal silicon becomes particularly susceptible to cracking.

[0024] 2, in the plasma processing apparatus 1, the single crystal silicon constituting the ceiling electrode plate 13A has a crystal orientation in the direction indicated by the crystal orientation Dc1. In other words, the crystal orientation is parallel to the surface 13AS of the ceiling electrode plate 13A. Therefore, the ceiling electrode plate 13A has a cleavage plane indicated by the line Lcs. The crystal orientation of the ceiling electrode plate 13A is determined by the cutting direction of the silicon ingot. When the silicon ingot is sliced ​​along the plane

[100] , assuming that the orientation during crystal growth is <100>, the planes

[010] and

[001] become cleavage planes.

[0025] The ceiling electrode plate 13A is heated by heat input from the plasma. The cooling plate 13B cools the ceiling electrode plate 13A. The ceiling electrode plate 13A is fastened to the cooling plate 13B by clamps 13C. The cooling plate 13B and the clamps 13C are each formed of a metal such as aluminum. The clamps 13C have contact portions 13Ca that contact a portion of the entire periphery of the ceiling electrode plate 13A. The clamps 13C fasten the ceiling electrode plate 13A to the cooling plate 13B.

[0026] When plasma processing is performed on the substrate W, the ceiling electrode plate 13A is heated by heat input from the plasma, and the temperature rises. As the temperature of the ceiling electrode plate 13A rises, the ceiling electrode plate 13A expands. When the plasma processing on the substrate W is completed and the heat input from the plasma ceases, the ceiling electrode plate 13A shrinks.

[0027] When plasma processing is repeated, the ceiling electrode plate 13A expands and contracts in the expansion direction Dt relative to the center PC of the ceiling electrode plate 13A. The thermal expansion coefficient of the ceiling electrode plate 13A differs from the thermal expansion coefficients of the cooling plate 13B and the clamp 13C. Therefore, when plasma processing is repeated, friction occurs between the ceiling electrode plate 13A and the clamp 13C. When friction occurs between the ceiling electrode plate 13A and the clamp 13C, scratches may occur on the ceiling electrode plate 13A in the direction of friction with the clamp 13C.

[0028] As described above, the ceiling electrode plate 13A, which is made of single-crystal silicon, a brittle material, is prone to cracking, particularly when scratches are made in the direction of the crystal orientation Dc1. Therefore, the inventors discovered that cracking of the ceiling electrode plate 13A can be suppressed by making the direction in which the ceiling electrode plate 13A expands and contracts due to temperature increases and decreases different from the direction of the crystal orientation at the portion of the ceiling electrode plate 13A where the clamp 13C contacts. As shown in FIG. 2 , the clamp 13C of the showerhead 13 holds the ceiling electrode plate 13A not around the entire circumference but only in a portion, specifically in four directions. When the direction in which the ceiling electrode plate 13A expands and contracts due to temperature increases and decreases (the expansion and contraction direction Dt) differs from the direction of the crystal orientation (see the crystal orientation Dc1), scratches along the crystal orientation of the ceiling electrode plate 13A can be suppressed. Suppressing scratches along the crystal orientation of the ceiling electrode plate 13A can suppress fracture of the ceiling electrode plate 13A.

[0029] FIG. 3 is a diagram illustrating the relationship between the crystal orientation and the expansion / contraction direction of the ceiling electrode plate 13A in the plasma processing apparatus 1, which is an example of the plasma processing apparatus according to this embodiment.

[0030] The clamp 13C has a contact portion 13Ca that comes into contact with the ceiling electrode plate 13A. The contact portion 13Ca comes into contact with a portion 13Ap of the ceiling electrode plate 13A.

[0031] The following describes the two crystal orientations (crystal orientation Dc11 and crystal orientation Dc12) in the single-crystal silicon that constitutes ceiling electrode plate 13A, and the expansion / contraction direction (expansion / contraction direction Dt11) that occurs when the temperature of ceiling electrode plate 13A increases or decreases. The angle between crystal orientation Dc11 and expansion / contraction direction Dt11 is defined as angle θ11, and the angle between the two crystal orientations, crystal orientation Dc11 and crystal orientation Dc12, is defined as angle θ12.

[0032] The expansion / contraction direction Dt11 of portion 13Ap of ceiling electrode plate 13A due to a rise and fall in temperature is 30% to 70% of the angle between crystal orientations Dc11 and Dc12, which are two crystal orientations in portion 13Ap of ceiling electrode plate 13A. In other words, angle θ11 is 30% to 70% of angle θ12.

[0033] 3, angle θ12 is 90 degrees, and angle θ11 is 45 degrees. In other words, the expansion / contraction direction (expansion / contraction direction Dt11) of portion 13Ap of ceiling electrode plate 13A due to a rise and fall in temperature is the middle direction of the angle formed by two crystal orientations, crystal orientations Dc11 and Dc12.

[0034] In the present disclosure, the term "midpoint of the angle" does not necessarily mean that the angle is exactly halfway. For example, if the midpoint of the angle is within a range that is acceptable for manufacturing purposes, the midpoint of the angle is included in the midpoint of the angle.

[0035] According to the plasma processing apparatus of this embodiment, the first direction in which the first member expands and contracts due to temperature rise and fall at the contact point is different from the second direction of the crystal orientation of the first member at that point, thereby suppressing a decrease in strength due to scratches and preventing damage to the first member.

[0036] <Modifications> A modification of the plasma processing apparatus according to this embodiment will be described. Fig. 4 is a diagram illustrating a holding structure of a ceiling electrode plate 113A, which is an example of a ceiling electrode plate in a modification of the plasma processing apparatus according to this embodiment. Fig. 5 is a diagram illustrating the relationship between the crystal orientation and the expansion / contraction direction of the ceiling electrode plate 113A, which is an example of a ceiling electrode plate in a modification of the plasma processing apparatus according to this embodiment.

[0037] The ceiling electrode plate 113A has a different crystal orientation in the single crystal silicon from the ceiling electrode plate 13A. The ceiling electrode plate 113A is an example in which the cleavage plane is the

[111] plane.

[0038] The shower head 113 includes a ceiling electrode plate 113A, a cooling plate 13B, and a clamp 113C. The cooling plate 13B is not shown in Fig. 4. As shown in Fig. 4, the clamp 113C of the shower head 113 holds the ceiling electrode plate 113A not around the entire periphery but only partly, specifically in six directions.

[0039] 4, the single-crystal silicon constituting the ceiling electrode plate 113A in the shower head 113 has a crystal orientation in the direction indicated by the crystal orientation Dc11 on the surface 113AS. Therefore, the ceiling electrode plate 113A has a cleavage plane indicated by the line Lcs on the surface 113AS.

[0040] When the plasma processing is repeated, the ceiling electrode plate 113A expands and contracts in the expansion and contraction direction Dt relative to the center PC of the ceiling electrode plate 113A due to the rise and fall of the temperature.

[0041] FIG. 5 is a diagram illustrating the relationship between the crystal orientation and the expansion / contraction direction of the ceiling electrode plate 113A, which is an example of the ceiling electrode plate in the plasma processing apparatus according to this embodiment.

[0042] The clamp 113C has a contact portion 113Ca that comes into contact with the ceiling electrode plate 113A. The contact portion 113Ca comes into contact with the ceiling electrode plate 113A at a portion 113Ap.

[0043] The following describes the two crystal orientations (crystal orientation Dc21 and crystal orientation Dc22) in the single-crystal silicon that constitutes ceiling electrode plate 113A, and the expansion / contraction direction (expansion / contraction direction Dt21) of ceiling electrode plate 113A due to increases and decreases in temperature. The angle between crystal orientation Dc21 and expansion / contraction direction Dt21 is defined as angle θ21, and the angle between the two crystal orientations, crystal orientation Dc21 and crystal orientation Dc22, is defined as angle θ22.

[0044] The expansion and contraction direction (expansion and contraction direction Dt21) due to the rise and fall of temperature in portion 113Ap of ceiling electrode plate 113A is a direction that is 30% to 70% of the angle between crystal orientations Dc21 and Dc22, which are two crystal orientations in portion 13Ap of ceiling electrode plate 113A. In other words, angle θ21 is 30% to 70% of angle θ22.

[0045] 5, angle θ22 is 60 degrees, and angle θ11 is 30 degrees. In other words, the expansion / contraction direction (expansion / contraction direction Dt21) of portion 113Ap of ceiling electrode plate 113A due to a rise and fall in temperature is the middle direction of the angle formed by two crystal orientations, crystal orientations Dc21 and Dc22.

[0046] <Example of Holding Ceiling Electrode Plate by Clamp> A specific example of holding ceiling electrode plate 13A by clamp 13C will be described below. Fig. 6 is a diagram illustrating a holding structure of ceiling electrode plate 13A in plasma processing apparatus 1, which is an example of the plasma processing apparatus according to this embodiment.

[0047] It is desirable that the ceiling electrode plate 13A be held by the clamp 13C with as small a contact area as possible. The clamp 13C has a protrusion 13Cp on the surface that holds the ceiling electrode plate 13A, which protrudes toward the ceiling electrode plate 13A. The protrusion 13Cp extends along the expansion / contraction direction Dt of the ceiling electrode plate 13A.

[0048] Clamp 13C has protrusion 13Cp, which reduces the contact area with ceiling electrode plate 13A. By setting the direction in which the contacting portion of ceiling electrode plate 13A extends to expansion / contraction direction Dt of ceiling electrode plate 13A, the direction in which the first member expands and contracts due to temperature rise and fall can be appropriately made different from the direction of the crystal orientation of the first member at that portion.

[0049] <Load on Ceiling Electrode Plate> The load on the ceiling electrode plate will be described. For example, in the case of single-crystal silicon, it is known that if the load on the microcontact point is 0.01 Newtons or less, even if the surface of the single-crystal silicon is scratched, the impact of scratches on the single-crystal silicon crystal is small, and the fracture strength is largely maintained. Here, the load on the ceiling electrode plate 13A in the plasma processing apparatus 1 will be described. The force pressing the ceiling electrode plate 13A at the contact portion 13Ca of the clamp 13C should be smaller than the force that would damage the crystal of the ceiling electrode plate 13A. For example, in the plasma processing apparatus 1, the pressure at the contact portion can be calculated by dividing the force applied when fastening the ceiling electrode plate 13A with the clamp 13C by the contact area between the ceiling electrode plate 13A and the clamp 13C. Then, the load at the microscopic contact portion can be calculated by multiplying this pressure by the area that is considered to be in microscopic contact based on, for example, surface roughness. The fastening force, pressure, contact area, etc. are set so that the load at the microscopic contact portion is 0.01 Newtons or less.

[0050] For example, suppose ceiling electrode plate 13A is fastened by clamp 13C with a force of N1 Newtons. The contact area between ceiling electrode plate 13A and clamp 13C is S1 square meters. Then, the portion where ceiling electrode plate 13A and clamp 13C are in contact is fastened with a pressure of N1 / S1 Pascals. If the area of ​​the microscopic contact portion is, for example, S2 square meters, the load on the microscopic contact portion is N1 x S2 / S1 Newtons. For example, if the surface roughness is Ra 1.0, then the average area S2 of the actual contact portion when viewed microscopically is approximately 0.01 square millimeters.

[0051] By setting the fastening force, contact area, and surface roughness so that the calculated load at the microscopic contact point is 0.01 Newtons or less, damage to the ceiling electrode plate 13A can be suppressed at the contact point between the ceiling electrode plate 13A and the clamp 13C.

[0052] The plasma processing apparatus according to the present embodiment disclosed herein should be considered to be illustrative in all respects and not restrictive. The above-described embodiments can be modified and improved in various ways without departing from the spirit and scope of the appended claims. The features described in the above-described embodiments can be configured in other ways as long as they are not inconsistent, and can be combined as long as they are not inconsistent.

[0053] This application claims priority from basic patent application No. 2023-182246, filed on October 24, 2023, with the Japan Patent Office, the entire contents of which are incorporated herein by reference.

[0054] 1 Plasma processing apparatus 13, 113 Shower head 13A, 113A Ceiling electrode plate 13Ap, 113Ap Part 13AS, 113AS Surface 13B Cooling plate 13C, 113C Clamp 13Ca, 113Ca Contact part 13Cp Convex part Dc1, Dc11, Dc12, Dc21, Dc22 Crystal orientation Dt, Dt11, Dt21 Extension direction θ11, θ12, θ21, θ22 Angle

Claims

1. A plasma processing apparatus comprising: a first member made of a material having a crystal orientation; a second member; and a fastening member having a contact portion that contacts a portion of the entire circumference of the first member and fastens the first member to the second member, wherein a first direction in which the first member expands and contracts due to increases and decreases in temperature at a portion of the first member where the contact portion is in contact is different from a second direction of the crystal orientation of the first member at that portion.

2. The plasma processing apparatus according to claim 1, wherein the first direction is a direction that is 30% to 70% of the angle between two crystal orientations in the first member.

3. The plasma processing apparatus according to claim 2, wherein the first direction is a direction intermediate an angle between two crystal orientations in the first member.

4. The plasma processing apparatus according to claim 1, wherein the force with which the contact portion presses the first member is smaller than a force that would damage a crystal in the first member.

5. The plasma processing apparatus according to claim 4, wherein the material having the crystal orientation is single crystal silicon, and the force with which the contact portion presses the first member is less than 0.01 Newtons.

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