electrostatic chuck

Abstract

It reduces the risk of arcing while suppressing residual adsorption of the target object. [Solution] The holding member comprises a plate-shaped member 10 and an electrode provided inside the plate-shaped member 10. The plate-shaped member 10 has a first main surface 11, a first protrusion 12B1 protruding from the first main surface 11 and supporting the object, and a second protrusion 12B2 protruding from the first main surface 11, with the second protrusion 12B2 surrounding the first protrusion 12B1. The charge leaking from the first protrusion 12B1 supporting the object is trapped on the first main surface 11 located between the first protrusion 12B1 and the second protrusion 12B2, so the charge does not diffuse throughout the entire first main surface 11. Therefore, even if the application of voltage to the electrode is stopped, it is possible to avoid the adsorption between the object and the plate-shaped member 10 being maintained. In addition, it is not necessary to form a groove, and the distance between the first main surface 11 and the electrode is not shortened, so the risk of arcing can be reduced.

Description

Technical Field

[0001] The present disclosure relates to a holding member.

Background Art

[0002] As a holding device for holding a wafer when manufacturing semiconductors, for example, an electrostatic chuck is used. The electrostatic chuck includes a ceramic member having an adsorption surface and a chuck electrode provided inside the ceramic member, and adsorbs and holds a wafer on the adsorption surface of the ceramic member by utilizing the electrostatic attraction generated when a voltage is applied to the chuck electrode.

[0003] For example, the electrostatic chuck described in International Publication No. WO 2024 / 057973 (Patent Document 1 below) includes a dielectric and an electrode provided inside the dielectric. The dielectric has a first main surface, a contact support portion that protrudes from the first main surface and contacts the back surface of a substrate to support the substrate, and a groove portion provided between the first main surface and the contact support portion so as to surround the contact support portion.

[0004] When no groove portion is provided, a recessed surface that does not contact the substrate is formed around the contact support portion. Charges leaking from the contact surface on which the substrate is placed move to the non-contact recessed surface with the substrate due to the adsorption voltage applied to the electrostatic electrode, and charges accumulate on the recessed surface. As a result, a Coulomb force is generated between the charges of the substrate and the charges accumulated on the recessed surface, and the electrostatic adsorption between the substrate and the electrostatic chuck is maintained even when the application of the adsorption voltage to the electrostatic electrode is stopped.

[0005] According to the electrostatic chuck described in Patent Document 1 below, charges leaking from the contact surface on which the substrate is placed accumulate on the bottom surface of the groove portion and do not diffuse to the recessed surface, so that it is possible to avoid the situation where the electrostatic adsorption between the substrate and the electrostatic chuck is maintained (residual adsorption of the substrate).

Prior Art Literature

Patent Literature

[0006] [Patent Document 1] International Publication No. 2024 / 057973 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, in the electrostatic chuck described above, since the groove is formed by further machining downwards from the recessed surface, the distance between the bottom of the groove and the electrostatic electrode becomes shorter, which may increase the risk of arcing. [Means for solving the problem]

[0008] The holding member of this disclosure comprises a plate-shaped member and an electrode provided inside the plate-shaped member, wherein the plate-shaped member has a first main surface, a first convex portion protruding from the first main surface and supporting an object, and a second convex portion protruding from the first main surface, and the second convex portion is provided so as to surround the first convex portion. [Effects of the Invention]

[0009] According to this disclosure, residual adsorption of the target object can be suppressed while reducing the risk of arcing. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a schematic perspective view showing the external configuration of the electrostatic chuck according to Embodiment 1. [Figure 2] Figure 2 is a schematic cross-sectional view of an electrostatic chuck. [Figure 3] Figure 3 is a schematic plan view of an electrostatic chuck. [Figure 4] Figure 4 illustrates an example of a method for forming a protrusion. [Figure 5] Figure 5 is a cross-sectional view showing the state when a voltage is applied to the chuck electrode. [Figure 6] Figure 6 is a cross-sectional view showing the state when the voltage applied to the chuck electrode has been removed. [Figure 7]Figure 7 is a cross-sectional view illustrating the problems with conventional electrostatic chucks. [Figure 8] Figure 8 is a cross-sectional view showing the state in which a voltage is applied to the chuck electrode according to Embodiment 2. [Modes for carrying out the invention]

[0011] [Description of Embodiments in this Disclosure] First, embodiments of this disclosure will be listed and described. (1) The holding member of the present disclosure comprises a plate-shaped member and an electrode provided inside the plate-shaped member, wherein the plate-shaped member has a first main surface, a first convex portion protruding from the first main surface and supporting an object, and a second convex portion protruding from the first main surface, and the second convex portion is provided so as to surround the first convex portion.

[0012] The charge leaking from the first protrusion supporting the object is trapped on the first main surface located between the first and second protrusions, so the charge does not diffuse across the entire first main surface. Therefore, even when the application of voltage to the electrodes is stopped, it is possible to avoid the adsorption between the object and the plate-like member being maintained. Furthermore, since it is not necessary to further machine downwards from the first main surface located between the first and second protrusions to form a groove, the distance between the first main surface and the electrode does not shorten, thus reducing the risk of arcing.

[0013] (2) In the retaining member described in (1), it is preferable that the height of the first protrusion is greater than the height of the second protrusion. Since the second protrusion does not come into contact with the object, the generation of particles caused by the second protrusion coming into contact with the object can be prevented.

[0014] (3) In the retaining member described in (1) or (2), it is preferable that the roughness of the protruding end face of the first protrusion is smaller than the roughness of the first main surface located between the first protrusion and the second protrusion. Since the protruding end face of the first convex portion supports the object, it is preferably a mirror surface from the viewpoint of preventing the generation of particles. In the above configuration, the roughness of the protruding end face of the first convex portion is smaller than the roughness of the first main surface located between the first convex portion and the second convex portion, so it becomes easier to prevent the generation of particles caused by the contact of the first convex portion with the object. On the other hand, the first main surface located between the first convex portion and the second convex portion is preferably a rough surface from the viewpoint of trapping leaked electric charge. In the above configuration, the roughness of the first main surface located between the first convex portion and the second convex portion is larger than the roughness of the protruding end face of the first convex portion, so it becomes easier to trap leaked electric charge.

[0015] (6) In the holding member according to any one of (1) to (3) above, it is preferable that the roughness of the protruding end face of the first convex portion is smaller than the roughness of the protruding end face of the second convex portion. Since the protruding end face of the first convex portion supports the object, it is preferably a mirror surface from the viewpoint of preventing the generation of particles. In the above configuration, the roughness of the protruding end face of the first convex portion is smaller than the roughness of the protruding end face of the second convex portion, so it becomes easier to prevent the generation of particles caused by the contact of the first convex portion with the object. On the other hand, the protruding end face of the second convex portion is preferably a rough surface from the viewpoint of trapping leaked electric charge. In the above configuration, the roughness of the protruding end face of the second convex portion is larger than the roughness of the protruding end face of the first convex portion, so it becomes easier to trap leaked electric charge.

[0016] (5) In the holding member according to any one of (1) to (4), it is preferable that the plate-shaped member further comprises: an annular third convex portion protruding from an outer edge of the first main surface and supporting the object; and a fourth convex portion protruding from the first main surface along an inner surface of the third convex portion. Electric charge leaked from the third convex portion that supports the object is trapped on the first main surface located between the third convex portion and the fourth convex portion, so the electric charge does not diffuse throughout the entire first main surface. Therefore, it is possible to avoid the situation where the adsorption between the object and the holding member is maintained even after the application of voltage to the electrode is stopped.

[0017] The holding member according to any one of (6) (1) to (5), wherein it is preferable that the plate-shaped member further has a groove recessed from the first main surface located between the first convex portion and the second convex portion. Leaked charges are also trapped on the inner surface of the groove, so the trappable volume can be increased. At this time, since the groove is surrounded by the second convex portion, the trappable volume can be increased without increasing the depth of the groove compared to the case where the second convex portion is not provided.

[0018] [Detailed Description of Embodiments of the Present Disclosure] <Embodiment 1> Specific examples of Embodiment 1 of the present disclosure will be described with reference to FIGS. 1 to 7. It should be noted that the present disclosure is not limited to these examples, but is defined by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims are included. In the following description, for a plurality of identical members, reference numerals are only given to some members, and reference numerals for other members may be omitted. In this specification, the configuration of the holding member will be described with the positive Z-axis direction as the upward direction, the negative Z-axis direction as the downward direction, and the XY plane direction as the horizontal direction, but different arrangements may be adopted in the actual use mode of the holding member. In addition, in this specification, "orthogonal" shall also include arrangements that are recognized as substantially orthogonal.

[0019] <Electrostatic Chuck> The holding member provided with the plate-shaped member 10 of the present disclosure is an electrostatic chuck 1 capable of attracting and holding an object such as a semiconductor wafer or a glass substrate (hereinafter referred to as "wafer W"). The electrostatic chuck 1 is, for example, attached to a processing chamber of a semiconductor manufacturing apparatus (not shown), and is used for performing various processes (film formation, etching, etc.) on the wafer W using plasma. The electrostatic chuck 1 is an example of the holding member of the present disclosure.

[0020] As shown in Figure 1, the electrostatic chuck 1 comprises a plate-shaped member 10 and a base member 20. Note that the detailed configuration of the plate-shaped member 10 is omitted from the illustration in Figure 1. The plate-shaped member 10 and the base member 20 are joined by a joint 30. The joint 30 is made of an adhesive such as a silicone resin, acrylic resin, or epoxy resin. The electrostatic chuck 1 is capable of holding a wafer W by electrostatic attraction.

[0021] The base member 20 is a disc-shaped member, and can be formed into a shape with, for example, a diameter of about 340 mm and a thickness of about 35 mm. The main material forming the base member 20 is a conductive material such as aluminum or an aluminum alloy. Here, "main material forming the base member" refers to the main component, meaning the material with the highest content (weight percentage) (the same applies hereinafter). The upper surface S3 of the base member 20 is positioned on the plate-shaped member 10 side. The upper surface S3 of the base member 20 is joined to the joining surface S2 of the plate-shaped member 10, which will be described later, by the joining portion 30.

[0022] As shown in Figure 2, a refrigerant channel 21 is provided inside the base member 20. The refrigerant channel 21 is connected to a refrigerant circulation device (not shown). The refrigerant circulation device is configured to circulate a refrigerant such as a fluorine-based inert liquid or water through the refrigerant channel 21. When refrigerant flows through the refrigerant channel 21, the base member 20 is cooled, and the plate-shaped member 10 is cooled by heat transfer (heat dissipation) between the base member 20 and the plate-shaped member 10 via the joint 30, thereby cooling the wafer W held by the adsorption surface S1 of the plate-shaped member 10, which will be described later. This allows the temperature of the wafer W to be controlled.

[0023] <Plate-shaped member> The plate-shaped member 10 is generally disc-shaped and can be formed into a shape with, for example, a diameter of about 300 mm and a thickness of about 5 mm. The plate-shaped member 10 is an insulating substrate. The main material used to form the plate-shaped member 10 is, for example, ceramics (details will be described later).

[0024] The upper surface of the plate-shaped member 10 is an adsorption surface S1 perpendicular to the Z-axis direction. On the plate-shaped member 10, the joining surface S2 located on the opposite side of the adsorption surface S1 is joined to the base member 20 via a joint 30. Both the adsorption surface S1 and the joining surface S2 are mirror-polished.

[0025] The plate-shaped member 10 comprises a central portion 10A and a flange portion 10B that extends around the outer circumference of the central portion 10A. The central portion 10A extends upward above the flange portion 10B. A focus ring or the like (not shown) is mounted on the upper surface of the flange portion 11B.

[0026] <Chuck electrode> A chuck electrode 40 made of a conductive material (e.g., tungsten, molybdenum, platinum, etc.) is positioned inside the plate-shaped member 10. The chuck electrode 40 is positioned close to the adsorption surface S1. The shape of the chuck electrode 40 in the Z-axis direction is, for example, approximately circular.

[0027] <Gas flow path> A gas passage 13 is formed inside the plate-shaped member 10. The gas passage 13 includes a first gas passage 13A, a third gas passage 13C that communicates with the first gas passage 13A and opens to the first main surface 11 (described later), and a second gas passage 13B that communicates with the first gas passage 13A and opens to the joint surface S2 of the plate-shaped member 10. The first gas passage 13A is a space that extends in the XY plane direction (horizontal direction). The first gas passage 13A may, for example, extend in the radial direction of the plate-shaped member 10, or it may extend in a concentric shape when viewed in the Z axis direction. The first gas passage 13A is located below the chuck electrode 40.

[0028] The third gas channel 13C extends upward from the first gas channel 13A. The third gas channel 13C is provided in a manner that penetrates the chuck electrode 40. For example, the third gas channel 13C is located inside a through-hole provided in the chuck electrode 40.

[0029] The second gas passage 13B is a space that extends mainly in the vertical direction. The second gas passage 13B communicates with an inlet hole 22 that is formed by penetrating the base member 20 and the joint 30 in the vertical direction. The inlet hole 22 is formed to extend from the lower surface S4 of the base member 20 to the upper surface S3 and further to the joint 30. Although not shown, a gas cylinder or vacuum pump for supplying an inert gas (e.g., helium gas) is connected to the inlet hole 22 via piping.

[0030] <First main surface, convex part> The central portion 10A of the plate-shaped member 10 comprises a first main surface 11 and a plurality of protrusions 12B projecting upward from the first main surface 11. The first main surface 11 is located below the suction surface S1.

[0031] The protrusion 12B comprises, in detail, a first protrusion 12B1, a second protrusion 12B2, a third protrusion 12B3, and a fourth protrusion 12B4. The first protrusion 12B1 is cylindrical in shape. The second protrusion 12B2 is cylindrical and surrounds the first protrusion 12B1. As shown in Figure 3, the multiple first protrusions 12B1 and second protrusions 12B2 are arranged in a grid pattern, for example, with respect to the plate portion 12A, in a plan view. Alternatively, the multiple first protrusions 12B1 and second protrusions 12B2 may be arranged at predetermined intervals with respect to the center point of the plate portion 12A and on a virtual concentric circle centered on this center point.

[0032] The third protrusion 12B3 is provided in an annular shape, projecting upward from the outer edge of the first main surface 11. The fourth protrusion 12B4 is provided in an annular shape, projecting upward from the first main surface 11 along the inner surface of the third protrusion 12B3. Multiple first protrusions 12B1 and second protrusions 12B2 are arranged inside the fourth protrusion 12B4.

[0033] The height of the first protrusion 12B1 is greater than the height of the second protrusion 12B2. Also, the height of the third protrusion 12B3 is greater than the height of the fourth protrusion 12B4. As shown in Figure 5(B), the upper surface of the first protrusion 12B1 and the upper surface of the third protrusion 12B3 constitute the adsorption surface S1. In this way, the second protrusion 12B2 and the fourth protrusion 12B4 do not come into contact with the wafer W, thus preventing the generation of particles that would otherwise be caused by contact between the second protrusion 12B2 and the fourth protrusion 12B4 and the wafer W.

[0034] The roughness of the protruding end face of the first protrusion 12B1 is smaller than the roughness of the first main surface 11 located between the first protrusion 12B1 and the second protrusion 12B2. Since the protruding end face of the first protrusion 12B1 supports the wafer W, it is preferable that it be mirror-finished from the viewpoint of preventing particle generation. In this embodiment, since the roughness of the protruding end face of the first protrusion 12B1 is smaller than the roughness of the first main surface 11 located between the first protrusion 12B1 and the second protrusion 12B2, it is easier to prevent the generation of particles caused by the first protrusion 12B1 contacting the wafer W.

[0035] On the other hand, the first main surface 11 located between the first protrusion 12B1 and the second protrusion 12B2 is preferably rough from the viewpoint of trapping leaked charges. In this embodiment, the roughness of the first main surface 11 located between the first protrusion 12B1 and the second protrusion 12B2 is greater than the roughness of the protruding end face of the first protrusion 12B1, making it easier to trap leaked charges.

[0036] Similarly, the roughness of the protruding end face of the third protrusion 12B3 is less than the roughness of the first main surface 11 located between the third protrusion 12B3 and the fourth protrusion 12B4. Therefore, it is easier to prevent the generation of particles caused by the third protrusion 12B3 contacting the wafer W.

[0037] Since the protruding end faces of the first protrusion 12B1 and the third protrusion 12B3 support the wafer W, it is preferable that they be mirror-finished from the viewpoint of preventing particle generation. In this embodiment, the roughness of the protruding end face of the first protrusion 12B1 is smaller than that of the protruding end face of the second protrusion 12B2, and the roughness of the protruding end face of the third protrusion 12B3 is smaller than that of the protruding end face of the fourth protrusion 12B4, making it easier to prevent the generation of particles caused by the first protrusion 12B1 and the third protrusion 12B3 contacting the wafer W.

[0038] On the other hand, the protruding end faces of the second protrusion 12B2 and the fourth protrusion 12B4 are preferably rough from the viewpoint of trapping leaked charge. In this embodiment, the roughness of the protruding end faces of the second protrusion 12B2 and the fourth protrusion 12B4 is greater than the roughness of the protruding end faces of the first protrusion 12B1 and the third protrusion 12B3, making it easier to trap leaked charge.

[0039] <An example of a method for forming a protrusion> Next, an example of a method for forming the protrusions 12B will be explained with reference to Figure 4. In Figure 4, only the method for forming the first protrusion 12B1 and the second protrusion 12B2 of the protrusions 12B is explained, but the same applies to the method for forming the third protrusion 12B3 and the fourth protrusion 12B4. As shown in Figure 4(A), a first mask M1 and a second mask M2 are placed on the surface of the plate-shaped member 10. The first mask M1 is placed at the position for forming the first protrusion 12B1, and the second mask M2 is placed at the position for forming the second protrusion 12B2. A blasting nozzle N is placed above the plate-shaped member 10, and dry ice pellets are sprayed from the nozzle N toward the plate-shaped member 10 using compressed air. The surface of the plate-shaped member 10 is scraped due to the impact force of the dry ice particles, the resistance to expansion during sublimation, and the thermal contraction that occurs when the surface of the plate-shaped member 10 is rapidly cooled. As a result, as shown in Figure 4(B), the portion of the plate-shaped member 10 excluding the masks M1 and M2 is cut downwards.

[0040] Next, the second mask M2 is peeled off, leaving only the first mask M1 on the surface of the plate-shaped member 10. In this state, as shown in Figure 4(C), a nozzle N is placed above the plate-shaped member 10, and dry ice pellets are sprayed from the nozzle N toward the plate-shaped member 10 using compressed air. As a result, the portion of the plate-shaped member 10 excluding the first mask M1 is scraped away. After this, the first mask M1 is peeled off, forming a first protrusion 12B1 and a second protrusion 12B2 that protrude upward from the first main surface 12A1. The height from the first main surface 12A1 to the protruding end face of the first protrusion 12B1 is greater than the height from the first main surface 12A1 to the protruding end face of the second protrusion 12B2. In this way, the second protrusion 12B2 is formed so as to surround the first protrusion 12B1. The third protrusion 12B3 and the fourth protrusion 12B4 are also formed simultaneously with the first protrusion 12B1 and the second protrusion 12B2.

[0041] <Residual adsorption effect> Next, the residual adsorption effect will be explained with reference to Figures 5 to 7. Figure 5 shows the state in which a voltage is applied to the chuck electrode 40, and Figure 6 shows the state in which the voltage application is released. Figures 5(A) and 6(A) show a conventional structure in which only the first protrusion 12B1 is formed and the second protrusion 12B2 is not formed, while Figures 5(B) and 6(B) show the structure of the present disclosure in which both the first protrusion 12B1 and the second protrusion 12B2 are formed.

[0042] As shown in Figure 5(A), when a voltage is applied, the surface of the wafer W becomes negatively charged, and the surface of the chuck electrode 40 becomes positively charged, resulting in a polarized state and generating an electrostatic attraction based on the potential difference. At this time, negative charges move from the surface of the wafer W to the first main surface 11 due to the potential difference between the surface of the wafer W and the surface of the chuck electrode 40. The negative charges move to the first main surface 11 through the first protrusion 12B1 and the third protrusion 12B3 that are in contact with the wafer W. The first main surface 11 comprises a region R1 between the first protrusion 12B1 and the third protrusion 12B3, and a region R2 between adjacent first protrusions 12B1. The negative charges are distributed throughout regions R1 and R2 of the first main surface 11.

[0043] As shown in Figure 6(A), when the voltage is removed, the polarization state between the wafer W surface and the chuck electrode 40 surface disappears, and the electrostatic attraction is eliminated. However, since negative charges remain on the first main surface 11, a Coulomb force is generated between it and the wafer W, resulting in a state where the wafer W remains held on the adsorption surface S1 (residual adsorption).

[0044] As an example of a method to avoid residual adsorption, a method has been proposed in which a groove GP is formed around the first protrusion 12B1, as shown in Figure 7. The groove GP is formed by cutting downwards from the first main surface 11 toward the chuck electrode 40. In this way, negative charges are trapped in the groove GP and do not disperse across the entire first main surface 11, thus suppressing the generation of Coulomb force and avoiding residual adsorption. However, the distance from the bottom surface of the groove GP to the chuck electrode 40 becomes shorter (the insulating layer thickness decreases), and a corner is created on the bottom surface, which may increase the risk of arcing.

[0045] While it was known that forming grooves GP in this way could suppress residual adsorption of wafer W, no method was known for suppressing residual adsorption of wafer W while reducing the risk of arcing. Therefore, the inventors of this disclosure have found a method to suppress residual adsorption of wafer W while reducing the risk of arcing by forming a second protrusion 12B2 on the first main surface 11, rather than forming grooves GP on the first main surface 11.

[0046] As shown in Figure 5(B), when a voltage is applied, negative charges move to the first main surface 11 side through the first protrusion 12B1. The first main surface 11 comprises a region R3 between the second protrusion 12B2 and the fourth protrusion 12B4, and a region R4 between adjacent second protrusions 12B2. Negative charges leaking into the first protrusion 12B1 are trapped on the first main surface 11 located between the first protrusion 12B1 and the second protrusion 12B2, so negative charges do not diffuse into regions R3 and R4 of the first main surface 11. This is because a potential difference is generated between the wafer W surface and the chuck electrode 40 surface, so negative charges cannot flow back over the second protrusion 12B2. Since the Coulomb force is inversely proportional to the square of the distance, the Coulomb force decreases as the distance from the wafer W surface to the first main surface 11 increases, so it is preferable to make this distance shorter than the conventional structure shown in Figure 6(A).

[0047] The area of ​​the first main surface 11 located between the first protrusion 12B1 and the second protrusion 12B2 is smaller than the area of ​​regions R1 and R2 of the first main surface 11 in the conventional structure. Therefore, the amount of negative charge trapped on the first main surface 11 is less than in the conventional structure. Since the Coulomb force is proportional to the amount of charge, the Coulomb force is smaller than in the conventional structure. Thus, according to this embodiment, the Coulomb force is smaller than in the conventional structure while reducing the risk of arcing, and residual adsorption of the wafer W can be suppressed.

[0048] <Embodiment 2> Next, Embodiment 2 of the present disclosure will be described with reference to Figure 8. Unlike the plate-shaped member 10 of Embodiment 1, the plate-shaped member 110 of Embodiment 2 further has a groove 12C recessed from the first main surface 11 located between the first protrusion 12B1 and the second protrusion 12B2, and a groove 12D recessed from the first main surface 11 located between the third protrusion 12B3 and the fourth protrusion 12B4. The same reference numerals as in Embodiment 1 will be used for the same components as in Embodiment 1, and descriptions that overlap with Embodiment 1 will be omitted.

[0049] Since leaked negative charges are also trapped on the inner surfaces of grooves 12C and 12D, the volume that can be trapped can be increased. In this case, because grooves 12C and 12D are surrounded by the second protrusion 12B2 and the fourth protrusion 12B4, the volume that can be trapped can be increased without increasing the depth of grooves 12C and 12D compared to when the second protrusion 12B2 and the fourth protrusion 12B4 are not present. The depth of grooves 12C and 12D is set to a level that does not pose a risk of arcing with the chuck electrode 40.

[0050] <Other Embodiments> (1) In the above embodiments 1 and 2, the height of the first protrusion 12B1 is shown to be greater than the height of the second protrusion 12B2, but the height of the first protrusion 12B1 may be the same as the height of the second protrusion 12B2. Similarly, the height of the third protrusion 12B3 may be the same as the height of the fourth protrusion 12B4.

[0051] (2) In the above embodiments 1 and 2, the roughness of the protruding end face of the first protrusion 12B1 is shown to be smaller than the roughness of the first main surface 11 located between the first protrusion 12B1 and the second protrusion 12B2. However, the roughness of the protruding end face of the first protrusion 12B1 may be the same as the roughness of the first main surface 11 located between the first protrusion 12B1 and the second protrusion 12B2. Similarly, the roughness of the protruding end face of the third protrusion 12B3 may be the same as the roughness of the first main surface 11 located between the third protrusion 12B3 and the fourth protrusion 12B4.

[0052] (3) In the above embodiments 1 and 2, the roughness of the protruding end face of the first protrusion 12B1 is shown to be smaller than that of the protruding end face of the second protrusion 12B2. However, the roughness of the protruding end face of the first protrusion 12B1 may be the same as that of the protruding end face of the second protrusion 12B2. Similarly, the roughness of the protruding end face of the third protrusion 12B3 may be the same as that of the protruding end face of the fourth protrusion 12B4.

[0053] (4) In embodiments 1 and 2 described above, the plate-shaped member 10 is shown as having a third protrusion 12B3 and a fourth protrusion 12B4, but it may also have only one of the third protrusion 12B3 and the fourth protrusion 12B4, or neither.

[0054] (5) In the above embodiment 2, the plate-shaped member 110 is shown as having grooves 12C and 12D, but it may also have only one of the grooves 12C and 12D, or neither.

[0055] (6) In embodiments 1 and 2 described above, an electrostatic chuck 1 was used as an example of a holding member, but the invention is not limited thereto. For example, this disclosure can also be applied to heater devices such as CVD (Chemical Vapor Deposition) heaters and vacuum chucks. [Explanation of Symbols]

[0056] 1: Electrostatic chuck (holding member) 10,110: Plate-shaped member 10A: Center section 10B: Flange section 11: First main surface 12B: Convex part 12B1: First convex part 12B2: Second convex part 12B3: Third convex part 12B4: Fourth convex part 12C: Groove 12D: Groove 13: Gas flow path 13A: First gas flow path 13B: Second gas flow path 13C: Third gas flow path 20: Base component 21: Refrigerant flow path 22: Inlet hole 30: Joint 40: Chuck electrode GP:Groove R1,R2,R3,R4: area N: Nozzle M1: First mask M2: Second mask S1: Adsorption surface S2: Joint surface S3: Top surface S4: Bottom surface W: Wafer (object)

Claims

1. A plate-shaped member and The plate-shaped member comprises an electrode provided inside the plate-shaped member, The aforementioned plate-shaped member is The first main surface and, A first convex portion that protrudes from the first main surface and supports the object, It has a second protrusion that protrudes from the first main surface, A retaining member having the second protrusion provided so as to surround the first protrusion.

2. The retaining member according to claim 1, wherein the height of the first protrusion is greater than the height of the second protrusion.

3. The holding member according to claim 1 or claim 2, wherein the roughness of the protruding end surface of the first protrusion is smaller than the roughness of the first main surface located between the first protrusion and the second protrusion.

4. The holding member according to claim 1 or claim 2, wherein the roughness of the protruding end surface of the first protrusion is smaller than the roughness of the protruding end surface of the second protrusion.

5. The aforementioned plate-shaped member is A third annular protrusion that extends from the outer edge of the first main surface and supports the object, The retaining member according to claim 1 or claim 2, further comprising a fourth protrusion that protrudes from the first main surface along the inner surface of the third protrusion.

6. The aforementioned plate-shaped member is The retaining member according to claim 1 or claim 2, further having a groove recessed from the first main surface located between the first protrusion and the second protrusion.

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