Electrostatic chuck

Abstract

The present invention provides an electrostatic chuck which is configured so that an outer peripheral end portion of a dielectric substrate protrudes, but which is still capable of ensuring uniformity of plasma above the dielectric substrate. An electrostatic chuck (10) is provided with: a dielectric substrate (100); an RF electrode (140) provided inside the dielectric substrate (100); and a base plate (200) that is a metal member and that is bonded to the dielectric substrate (100). In plan view, the dielectric substrate (100) has a protruding part (101) that protrudes further outward than the surface (210) of the base plate (200), and a part of the RF electrode (140) is provided on the protruding part (101).

Description

Technical Field

[0001] The present invention relates to an electrostatic chuck. Background Art

[0002] For example, in a semiconductor manufacturing apparatus such as an etching apparatus, an electrostatic chuck is provided as an apparatus for adsorbing and holding a substrate such as a silicon wafer that is an object to be processed. The electrostatic chuck includes: a dielectric substrate provided with an adsorption electrode; and a base plate that supports the dielectric substrate, and has a structure in which these are joined to each other. When a voltage is applied to the adsorption electrode, an electrostatic force is generated to adsorb and hold the substrate placed on the dielectric substrate.

[0003] In a semiconductor manufacturing apparatus, an RF electrode is provided as a pair of opposed electrodes for generating plasma. As described in Patent Document 1 below, the base plate of the electrostatic chuck is sometimes used as one RF electrode. In addition, the RF electrode is sometimes incorporated in the dielectric substrate.

[0004] Patent Document Patent Document 1: Japanese Patent Application Laid-Open No. 2011-119654 Summary of the Invention

[0005] As a bonding layer for bonding between the dielectric substrate and the base plate, for example, a cured silicone adhesive is used. When performing a process such as etching, the end portion of the bonding layer is exposed to plasma and ages and scatters, which may have an adverse effect on the substrate being processed.

[0006] In order to prevent such a situation from occurring, the present inventors have developed an electrostatic chuck having such a structure that the dielectric substrate further protrudes outward compared to the bonded surface of the base plate, that is, an electrostatic chuck having a structure in which the outer peripheral side end portion of the dielectric substrate protrudes more outward than the bonded surface. By adopting such a structure, a member covering the periphery of the bonding layer can be disposed on the lower side of the dielectric substrate. Thereby, it is possible to suppress the bonding layer from affecting the substrate being processed.

[0007] If the outer peripheral side end portion of the dielectric substrate protrudes more outward than the bonded surface, the base plate serving as the RF electrode does not exist at the position directly below the protruding portion in the dielectric substrate. Therefore, above the protruding portion, the plasma tends to be non-uniform, and it may not be possible to perform processes such as etching evenly.

[0008] The present invention has been made in view of such problems, and the technical problem to be solved is to provide an electrostatic chuck that can ensure the uniformity of plasma on the upper side of the dielectric substrate although it has a structure in which the outer peripheral side end portion of the dielectric substrate protrudes.

[0009] In order to solve the above problems, the electrostatic chuck according to the present invention includes: a dielectric substrate having a placement surface for placing an object to be adsorbed; an RF electrode disposed inside the dielectric substrate; and a base plate, which is a member made of metal and is joined to the dielectric substrate. When viewed from a direction perpendicular to the placement surface, the dielectric substrate has a protruding portion that protrudes more outward than the joint surface of the base plate, and a part of the RF electrode is disposed in the protruding portion.

[0010] By disposing a part of the RF electrode in the protruding portion, it is possible to sandwich substantially the entire space directly above the dielectric substrate (including directly above the protruding portion) with a pair of electrodes including the RF electrode. Thereby, it is possible to ensure the uniformity of the plasma on the upper side of the dielectric substrate.

[0011] According to the present invention, it is possible to provide an electrostatic chuck that, although having a structure in which the outer peripheral side end portion of the dielectric substrate protrudes, can still ensure the uniformity of the plasma on the upper side of the dielectric substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a cross-sectional view schematically showing the structure of the electrostatic chuck according to the first embodiment. Figure 2 is an enlarged and detailed view showing Figure 1 a part of the structure of Figure 3 is a cross-sectional view showing a part of the structure of the electrostatic chuck according to a modification of the first embodiment. Figure 4 is a cross-sectional view showing a part of the structure of the electrostatic chuck according to the second embodiment. REFERENCE SIGNS 10 - electrostatic chuck; 100 - dielectric substrate; 101 - protruding portion; 110 - surface; 130 - adsorption electrode; 140 - RF electrode; 200 - base plate; 210 - surface. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0013] Hereinafter, the present embodiment will be described with reference to the drawings. For ease of understanding the description, in each drawing, the same reference signs are given to the same components as much as possible, and redundant description is omitted.

[0014] The first embodiment will be described. The electrostatic chuck 10 according to the present embodiment adsorbs and holds a substrate W to be processed by electrostatic force inside a semiconductor manufacturing apparatus (not shown) such as an etching apparatus. The object to be adsorbed, that is, the substrate W, is, for example, a silicon wafer. The electrostatic chuck 10 can also be used in apparatuses other than semiconductor manufacturing apparatuses.

[0015] Figure 1In [the figure], the structure of the electrostatic chuck 10 in a state of adsorbing and holding the substrate W is shown as a schematic cross-sectional view. The electrostatic chuck 10 includes a dielectric substrate 100 and a base plate 200.

[0016] The dielectric substrate 100 is a substantially disk-shaped member made of a ceramic sintered body. Although the dielectric substrate 100 contains, for example, high-purity alumina (Al2O3), it may also contain other materials. Considering the plasma resistance and the like required for the dielectric substrate 100 in a semiconductor manufacturing apparatus, the ceramic purity, type, additives, etc. in the dielectric substrate 100 can be appropriately set. The diameter of the dielectric substrate 100 is, for example, 290 to 300 mm. The thickness of the dielectric substrate 100 is, for example, 0.5 to 3.0 mm.

[0017] In the dielectric substrate 100, Figure 1 the upper-side surface 110 therein becomes the "placement surface" for placing the substrate W. In addition, in the dielectric substrate 100, Figure 1 the lower-side surface 120 therein becomes the "surface to be joined" that is joined to the base plate 200 via the joining layer 300. Hereinafter, the viewpoint when observing the electrostatic chuck 10 from the surface 110 side in a direction perpendicular to the surface 110 will also be referred to as "top view observation".

[0018] An adsorption electrode 130 is buried inside the dielectric substrate 100. The adsorption electrode 130 is a thin plate-shaped layer formed of a metal material such as tungsten, for example, and is disposed parallel to the surface 110. As the material of the adsorption electrode 130, in addition to tungsten, molybdenum, platinum, palladium, etc. can also be used. If a voltage is externally applied to the adsorption electrode 130 via a power supply circuit, an electrostatic force is generated between the surface 110 and the substrate W, whereby the substrate W is adsorbed and held. As the structure of the above-mentioned power supply circuit, various known structures can be adopted. The adsorption electrode 130 can be provided as a so-called "single-pole" electrode with only one as in this embodiment, or can be provided as a so-called "bipolar" electrode with two. The depth of the position where the adsorption electrode 130 is disposed, that is, the distance from the bottom surface 116 described later to the adsorption electrode 130 is, for example, 0.1 to 0.5 mm.

[0019] Inside the dielectric substrate 100, on the basis of the above-mentioned adsorption electrode 130, an RF electrode 140 is also buried. In a semiconductor manufacturing apparatus, the RF electrode 140 is provided as one of a pair of opposing electrodes for generating plasma. The other of the opposing electrodes is provided at a position closer to the upper side than the electrostatic chuck 10 in the semiconductor manufacturing apparatus. If a high-frequency alternating voltage is externally applied between these opposing electrodes, plasma is generated on the upper side of the substrate W and is used for processes such as film formation or etching of the substrate W.

[0020] Similar to the adsorption electrode 130, the RF electrode 140 is also a thin plate-shaped layer formed of a metal material such as tungsten. As the material of the RF electrode 140, in addition to tungsten, molybdenum, platinum, palladium, etc. can also be used. The RF electrode 140 is buried at a position closer to the surface 120 side than the adsorption electrode 130. Similar to the adsorption electrode 130, the RF electrode 140 is arranged parallel to the surface 110. When viewed from above, the RF electrode 140 is a substantially circular single electrode. When viewed from above, the center of the RF electrode 140 coincides with the center of the dielectric substrate 100. The distance from the adsorption electrode 130 to the RF electrode 140 is, for example, 0.2 to 2 mm. The distance from the RF electrode 140 to the surface 120 is, for example, 0.1 to 2.5 mm.

[0021] As Figure 1 shown, a power supply circuit 14 is connected to the RF electrode 140. The power supply circuit 14 is a circuit provided to make the potential of the RF electrode 140 consistent with the potential of the base plate 200 when a high-frequency alternating voltage is applied between the RF electrode 140 and another opposing electrode. Figure 1 In, the overall power supply circuit 14 is simply depicted. The power supply circuit 14 is formed, for example, as an electrode terminal such that one end is connected to the RF electrode 140 and the other end protrudes downward from the surface 120. The protruding part of the power supply circuit 14 as described above is buried in a recess (not shown) formed on the surface 210 of the base plate 200 and is connected to the metal part of the base plate 200. The number of the power supply circuits 14 can also be two or more.

[0022] As Figure 1 shown, a space SP is formed between the dielectric substrate 100 and the substrate W. When performing processes such as etching in a semiconductor manufacturing apparatus, helium for temperature adjustment is supplied from the outside to the space SP through a gas hole (not shown). By making helium exist between the dielectric substrate 100 and the substrate W, the thermal resistance between the two is adjusted, and thus the temperature of the substrate W is maintained at an appropriate temperature. Moreover, the gas for temperature adjustment supplied to the space SP can also be a gas of a different type from helium.

[0023] A sealing ring 111 and dots 112 are provided on the placement surface, i.e., the surface 110, and the space SP is formed around these.

[0024] The sealing ring 111 is a wall that divides the space SP at the outermost peripheral position. The sealing ring 111 is a ring-shaped protrusion formed on the surface 110 side. The top end ( Figure 1 the upper end in) of the sealing ring 111 becomes a part of the surface 110 and abuts against the substrate W. It can be said that the top end of the sealing ring 111 is the outermost peripheral side part of the placement surface, i.e., the surface 110.

[0025] Further, a plurality of sealing rings 111 may be provided in such a manner as to partition the space SP. With such a structure, the pressure of helium gas in each space SP can be adjusted individually, and the surface temperature distribution of the substrate W can be made uniform during processing.

[0026] Figure 1 In , the portion marked with the symbol "116" is the bottom surface of the space SP. Hereinafter, this portion will also be referred to as the "bottom surface 116". The sealing ring 111, together with the point 112 described below, is formed as a result of digging a part of the surface 110 to the position of the bottom surface 116.

[0027] The point 112 is a circular protrusion protruding from the bottom surface 116. A plurality of points 112 are provided and are disposed approximately evenly on the placement surface of the dielectric substrate 100. The tip of each point 112 becomes a part of the surface 110 and abuts against the substrate W. By providing a plurality of such points 112, the flexure of the substrate W is suppressed.

[0028] The base plate 200 is a substantially disk-shaped member that supports the dielectric substrate 100. The base plate 200 is formed of a metal material such as aluminum, for example. The base plate 200 is joined to the surface 120 of the dielectric substrate 100 by a joining layer 300. In the base plate 200, Figure 1 the upper surface 210 on the upper side thereof becomes the "surface to be joined" joined to the dielectric substrate 100.

[0029] The joining layer 300 is a layer provided between the dielectric substrate 100 and the base plate 200 and joins the two. The joining layer 300 is a layer formed by curing an adhesive made of an insulating material. In the present embodiment, a silicone adhesive is used as the above-mentioned adhesive. However, the joining layer 300 may also be a layer formed by curing other types of adhesives. In any case, it is preferable to use a material having a relatively high thermal conductivity as the material of the joining layer 300 so that the thermal resistance between the dielectric substrate 100 and the base plate 200 is small.

[0030] The base plate 200 has a support portion 201 and a flange portion 202. The support portion 201 is the Figure 1 upper portion in the base plate 200 and is a substantially cylindrical portion that directly supports the dielectric substrate 100 from below. Although the diameter of the support portion 201, that is, the diameter of the surface 210, is, for example, 290 to 300 mm, the same as that of the dielectric substrate 100, it is slightly smaller than the diameter of the dielectric substrate 100. The thickness of the support portion 201, that is, the protruding amount of the support portion 201 toward the Figure 1 upper side (the protruding amount from the flange portion 202) is, for example, 3 to 15 mm.

[0031] The flange portion 202 is the Figure 1The portion on the lower side in []. The shape of the flange portion 202 is substantially cylindrical, and its central axis coincides with the central axis of the support portion 201. The diameter of the flange portion 202 is larger than the diameter of the support portion 201. The protruding amount of the flange portion 202 starting from the outer side surface of the support portion 201 (that is, the protruding amount in the radial direction) is, for example, 20 to 30 mm. The thickness of the flange portion 202 is, for example, 25 to 40 mm. The overall thickness of the base plate 200 including the support portion 201 and the flange portion 202 is, for example, 30 to 40 mm.

[0032] When processing the substrate W in the semiconductor manufacturing apparatus, a focus ring (not shown) is provided on the upper surface 203 of the flange portion 202. The focus ring is a circular and plate-like member formed of an insulating material such as quartz, and is provided for the purpose of adjusting the distribution of the plasma during processing. Substantially the whole of the dielectric substrate 100 and the support portion 201 is in a state of being surrounded by the focus ring from the outer peripheral side.

[0033] Inside the base plate 200, a cooling medium flow path 250 for allowing a cooling medium to pass through is formed. When performing processing such as etching in the semiconductor manufacturing apparatus, the cooling medium is supplied from the outside to the cooling medium flow path 250, thereby cooling the base plate 200. During processing, the heat generated on the substrate W is transferred to the cooling medium through the helium gas in the space SP, the dielectric substrate 100, and the base plate 200, and is discharged to the outside together with the cooling medium.

[0034] As described above, in the electrostatic chuck 10 according to the present embodiment, the diameter of the support portion 201, which is the portion of the base plate 200 that directly supports the dielectric substrate 100, is smaller than the diameter of the dielectric substrate 100. As a result, the dielectric substrate 100 protrudes more outward than the joint surface, that is, the surface 210. Hereinafter, the protruding portion of the dielectric substrate 100 will also be referred to as "protruding portion 101". The protruding amount of the protruding portion 101, that is, the protruding amount of the dielectric substrate 100 from the outer side surface of the support portion 201 (the protruding amount in the radial direction) is, for example, 1 mm to 3 mm.

[0035] When performing processing such as etching, the end portion of the bonding layer 300 is exposed to the plasma, ages, and scatters, which may have an adverse effect on the substrate W being processed. As in the present embodiment, when the protruding portion 101 is provided on the dielectric substrate 100, a member that covers the exposed portion of the bonding layer 300 from the surroundings can be disposed on the lower side of the dielectric substrate 100. Figure 2 In [], the arrangement position of such a member is indicated by a double-dot chain line marked with the symbol "400". By arranging this member, the influence of the bonding layer 300 on the substrate W being processed can be suppressed.

[0036] However, in processes such as etching, it is required to ensure the uniformity of the plasma above the dielectric substrate 100 so that the processing can be carried out evenly. When there is no protrusion 101 provided on the dielectric substrate 100 and the entire surface 120 of the dielectric substrate 100 is supported from below by the base plate 200, for example, the base plate 200 functions as an RF electrode, thereby enabling the uniformity of the plasma to be ensured throughout the area directly above the surface 110. However, as in the present embodiment, when there is a protrusion 101 provided on the dielectric substrate 100, there is no base plate 200 acting as an RF electrode at the position directly below the protrusion 101. Therefore, above the protrusion 101, the plasma tends to be non-uniform, and it may not be possible to carry out processes such as etching evenly.

[0037] Then, in the electrostatic chuck 10 according to the present embodiment, a structure is formed in which an RF electrode 140 is provided inside the dielectric substrate 100. On this basis, the arrangement of the RF electrode 140 is studied, thereby ensuring the uniformity of the plasma during processing.

[0038] Figure 2 In, it is enlarged and shown in detail Figure 1 the structure of the protrusion 101 and its vicinity in the electrostatic chuck 10. Figure 2 The dotted line DL1 shown indicates the position of the outer peripheral side end of the joint surface, that is, the surface 210. The dotted line DL2 indicates the position of the outer peripheral side end of the adsorption electrode 130. The dotted line DL3 indicates the position of the outer peripheral side end of the RF electrode 140.

[0039] Moreover, the "outer peripheral side end" of the RF electrode 140 refers to the part where the smallest circle including the entire RF electrode 140 overlaps with the RF electrode 140 when viewed from above. The "outer peripheral side end" of the adsorption electrode 130 is defined in the same way.

[0040] The diameter of the outer peripheral side end of the RF electrode 140 is larger than the diameter of the surface 210 of the base plate 200. Therefore, the outer peripheral side end (dotted line DL3) of the RF electrode 140 enters the inside of the protrusion 101 in the dielectric substrate 100.

[0041] As in the present embodiment, in the structure in which a part of the RF electrode 140 is provided in the protrusion 101, it is possible to clamp substantially the entire space directly above the dielectric substrate 100 (including directly above the protrusion 101) with a pair of electrodes including the RF electrode 140. That is to say, although the structure is such that there is a protrusion 101 provided on the dielectric substrate 100, it is still possible to expand the RF electrode 140 to a larger range compared to the surface 210 of the base plate 200. Thereby, the uniformity of the plasma above the dielectric substrate 100 can be ensured.

[0042] In this embodiment, the diameter of the outer peripheral side end portion of the adsorption electrode 130 is larger than the diameter of the surface 210 of the base plate 200. That is to say, when viewed from above, not only the RF electrode 140 but also a part of the adsorption electrode 130 enters the protruding portion 101.

[0043] In this way, in the structure where a part of the adsorption electrode 130 is disposed in the protruding portion 101, the adsorption force on the protruding portion 101 of the substrate W increases, and the two are closely attached with a strong force. Although there is no cooling material, that is, the base plate 200, directly below the protruding portion 101, the thermal resistance between the protruding portion 101 and the substrate W decreases. Therefore, the temperature rise of the substrate W directly above the protruding portion 101 can be suppressed to a certain extent. As a result, the deviation of the in-plane temperature distribution of the substrate W during processing can be suppressed.

[0044] The diameter of the outer peripheral side end portion of the adsorption electrode 130 is larger than the diameter of the inner peripheral side in the sealing ring 111 and smaller than the diameter of the outer peripheral side in the sealing ring 111. In addition, the diameter of the outer peripheral side in the sealing ring 111 is larger than the diameter of the surface 210 of the base plate 200. When viewed from above, a part of the sealing ring 111 overlaps both the protruding portion 101 and the adsorption electrode 130. Since the sealing ring 111, the protruding portion 101, and the adsorption electrode 130 overlap when viewed from above, the cooling of the substrate W in this part can be further improved. As a result, the deviation of the in-plane temperature distribution of the substrate W can be further suppressed.

[0045] Moreover, it can also be configured such that, when viewed from above, not a part but the whole of the sealing ring 111 overlaps both the protruding portion 101 and the adsorption electrode 130. At this time, it is only necessary to make the diameter of the inner peripheral side in the sealing ring 111 larger than the diameter of the support portion 201. In addition, it is only necessary to make the diameter of the outer peripheral side in the sealing ring 111 smaller than the diameter of the dielectric substrate 100 and smaller than the diameter of the outer peripheral side end portion of the adsorption electrode 130.

[0046] In any case, it is preferable to ensure that the distance from the outer peripheral side end portion (dotted line DL2) of the adsorption electrode 130 to the outer side surface of the dielectric substrate 100 is about 0.1 mm to 3 mm. By ensuring such a distance, the insulation breakdown between the adsorption electrode 130 and the outside can be prevented.

[0047] The diameter of the outer peripheral side end portion (dotted line DL3) of the RF electrode 140 is larger than the diameter of the outer peripheral side end portion (dotted line DL1) of the adsorption electrode 130. That is to say, when viewed from above, the RF electrode 140 is disposed within a range where its outer peripheral side end portion is closer to the outer peripheral side than the outer peripheral side end portion of the adsorption electrode 130. It is preferable to ensure that the distance from the outer peripheral side end portion (dotted line DL3) of the RF electrode 140 to the outer side surface of the dielectric substrate 100 is about 0.1 mm to 2 mm.

[0048] The potential of the RF electrode 140 during processing is usually made lower than that of the adsorption electrode 130. As in the present embodiment, the outer peripheral end portion of the RF electrode 140 is extended to a position closer to the outside than the outer peripheral end portion of the adsorption electrode 130. Thus, within the range where insulation breakdown voltage can be ensured, the RF electrode 140 can be provided over as large a range as possible. As a result, the uniformity of the plasma can be ensured.

[0049] As described above, it is preferable that the diameter of the outer peripheral end portion of the RF electrode 140 is larger than the diameter of the bonding surface (surface 210) of the base plate 200. The "bonding surface" mentioned here refers to the surface of the metal portion of the base plate 200 that faces the dielectric substrate via the bonding layer 300. Even when the surface 210 is covered with an insulating film, the "bonding surface" can be defined in the same manner as above.

[0050] For example, in Figure 3 a modified example, an insulating film 230 is formed so as to cover the surface of the base plate 200 including the surface 210. The insulating film 230 is, for example, a film of alumina formed by sputtering. The thickness of the insulating film is, for example, 1 mm or less.

[0051] In addition, in Figure 3 a comparative example, the portion near the outer peripheral end portion in the surface 210 does not form a flat surface, but forms a surface that is curved in an arc shape. Hereinafter, the curved portion of the surface 210 will also be referred to as "surface 210A". In this modified example, the entire surface 210 including the surface 210A is defined as the "bonding surface" that is bonded to the dielectric substrate 100 via the insulating film 230 and the bonding layer 300.

[0052] Figure 3 In, the portion marked with the symbol "211" is the outer side surface of the support portion 201. Hereinafter, this outer side surface will also be referred to as "outer side surface 211". When viewed from above, the position of the outer peripheral end portion of the bonding surface (dashed line DL1) and the position of the outer side surface 211 are the same as each other.

[0053] As in this modified example, when the surface of the base plate 200 is covered with the insulating film 230, the portion of the dielectric substrate 100 that is closer to the outside than the dashed line DL1 when viewed from above corresponds to the protruding portion 101. In addition, the adsorption electrode 130 and the RF electrode 140 are formed to extend to a position closer to the outside than the dashed line DL1.

[0054] A description will be given of the second embodiment. Hereinafter, mainly the portions different from the first embodiment will be described, and the portions common to the first embodiment will be appropriately omitted.

[0055] Figure 4 In, in order toFigure 2 The same viewpoint depicts the structure of the electrostatic chuck 10 according to the present embodiment. As Figure 4 shown, in the present embodiment, the diameter of the outer peripheral side end portion (dashed line DL3) of the RF electrode 140 is smaller than the diameter of the outer peripheral side end portion (dashed line DL2) of the adsorption electrode 130. That is, when viewed from above, the RF electrode 140 is disposed within a range closer to the inner peripheral side than the outer peripheral side end portion of the adsorption electrode 130.

[0056] When processing the substrate W, Joule heat is generated on the RF electrode 140, which may cause the temperature of the surrounding components to rise. That is, during processing, the RF electrode 140 may become a heat source. Thus, in the present embodiment, as described above, the RF electrode 140 is disposed within a range closer to the inner side than the outer peripheral side end portion of the adsorption electrode 130. By accommodating the heat source, that is, the RF electrode 140, within the above range, it is possible to suppress the temperature rise in the portion on the outer peripheral side of the substrate W.

[0057] Moreover, when viewed from above, the outer peripheral side end portion of the RF electrode 140 may also overlap with the outer peripheral side end portion of the adsorption electrode 130. That is, it is only necessary to dispose the RF electrode 140 within a range where its outer peripheral side end portion does not overflow from the outer peripheral side end portion of the adsorption electrode 130.

[0058] In the structure in which the outer peripheral side end portion of the RF electrode 140 enters the protrusion 101, when the heat generation of the RF electrode 140 becomes a problem, the structure of the present embodiment may be adopted instead of the first embodiment.

[0059] As described above, the present embodiment has been described with reference to specific examples. However, the present invention is not limited to these specific examples. Regarding these specific examples, as long as they have the features of the present invention, the techniques appropriately designed and modified by those skilled in the art are also included in the scope of the present invention. The elements, their arrangements, conditions, shapes, etc. possessed by the foregoing specific examples are not limited to the illustrated contents, but may be appropriately changed. As long as there is no technical contradiction, the elements possessed by the foregoing specific examples may be appropriately changed in combination.

Claims

1. An electrostatic chuck, characterized in that: It includes: a dielectric substrate having a placement surface for placing an object to be adsorbed; An RF electrode disposed inside the dielectric substrate; And a base plate, which is a member made of metal and is joined to the dielectric substrate. When viewed from a direction perpendicular to the placement surface, The dielectric substrate has a protruding portion that protrudes more outward than the joint surface of the base plate. A part of the RF electrode is disposed in the protruding portion.

2. The electrostatic chuck according to claim 1, characterized in that: It further includes an adsorption electrode disposed inside the dielectric substrate. When viewed from a direction perpendicular to the placement surface, A part of the adsorption electrode is disposed in the protruding portion.

3. The electrostatic chuck according to claim 2, characterized in that: When viewed from a direction perpendicular to the placement surface, The RF electrode is disposed within a range where its outer peripheral side end is closer to the outer peripheral side than the outer peripheral side end of the adsorption electrode.

4. The electrostatic chuck according to claim 2, characterized in that: When viewed from a direction perpendicular to the placement surface, The RF electrode is disposed within a range where its outer peripheral side end does not spill out from the outer peripheral side end of the adsorption electrode.

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