Electrostatic chuck

Abstract

The present invention provides an electrostatic chuck having satisfactory electrical characteristics (discharge suppression, electrostatic characteristics, etc.). This electrostatic chuck (10) has a recess (12) in a placement surface (11), and is provided with: one or a plurality of electrodes (13) disposed along the placement surface (11); a base (14); and a dielectric layer (15) in which the electrodes (13) are stacked between the base (14) and the placement surface (11). The electrostatic chuck has a region in which the recess (12) and the electrodes (13) overlap in a plan view as seen from a direction perpendicular to the placement surface (11).

Description

Electrostatic chuck

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

[0002] When performing processes such as processing a substrate or forming a film on a substrate using a substrate such as a semiconductor wafer, a glass substrate, or an insulating substrate, it is necessary to hold the substrate at a predetermined position. Conventionally, a mechanical chuck device using a mechanical method, a vacuum chuck device using vacuum suction, etc. have been used, but in recent years, an electrostatic chuck device using electrostatic adsorption has been used. The electrostatic chuck device includes an internal electrode covered with a dielectric layer. When a voltage is applied to the internal electrode to generate a potential difference between the substrate and the electrode, an electrostatic attractive force is generated between the dielectric layers. As a result, the substrate is supported substantially parallel to the internal electrode.

[0003] Patent Document 1 describes a mounting table for mounting a substrate to be subjected to plasma treatment, which has a supply hole for supplying a heat medium between the electrostatic chuck and the edge ring, and the groove provided in at least one of the edge ring and the mounting table is not provided above the supply hole.

[0004] Japanese Patent Application Laid-Open No. 2019-216176

[0005] When a supply hole for supplying a heat medium such as gas is not provided in the groove, it is difficult to circulate the heat medium along the mounting surface. In the invention described in Patent Document 1, in order to suppress abnormal discharge, it is described that a groove is provided on the back surface of the edge ring without forming a groove on the mounting surface above the supply hole, but the structure of the edge ring becomes complicated.

[0006] The present invention has been made in view of the above circumstances, and an object thereof is to provide an electrostatic chuck having good electrical characteristics (such as suppression of discharge and electrostatic characteristics).

[0007] The present invention includes the following embodiments: [1] An electrostatic chuck having a recess on a mounting surface, comprising one or more electrodes arranged along the mounting surface, a base, and a dielectric layer on which the electrodes are laminated between the base and the mounting surface, wherein in a plan view taken from a direction perpendicular to the mounting surface, the recess and the electrodes overlap in a region. [2] The electrostatic chuck according to [1], wherein the electrodes are a plurality of electrodes, and in the region on which the recess and the electrodes overlap, the same recess overlaps with the plurality of electrodes. [3] The electrostatic chuck according to [1] or [2], wherein in a plan view taken from a direction perpendicular to the mounting surface, the ends of one or more recesses overlap with one or more electrodes. [4] The electrostatic chuck according to any one of [1] to [3], wherein the electrical resistivity of the member mounted on the mounting surface is that of a semiconductor member or a conductor member. [5] The electrostatic chuck according to any one of [1] to [4], wherein the recess is a groove. [6] The electrostatic chuck according to any one of [1] to [5], wherein the recess is an annular groove. [7] The electrostatic chuck according to any one of [1] to [6], wherein the shape of the member placed on the mounting surface is ring-shaped. [8] The electrostatic chuck according to any one of [1] to [7], wherein a ridge is provided on the outer circumference of the mounting surface, and a curved surface is provided at the end of the ridge. [9] The electrostatic chuck according to any one of [1] to [8], wherein the depth of the recess is 0.05 mm or less.

[0008] According to the present invention, an electrostatic chuck with good electrical properties (discharge suppression, electrostatic properties, etc.) can be provided by having a region in which the recess and the electrode overlap in a plan view taken from a direction perpendicular to the mounting surface.

[0009] This is a cross-sectional view showing an example of an electrostatic chuck. This is a cross-sectional view showing an electrostatic chuck of Embodiment A. This is a cross-sectional view showing an electrostatic chuck of Embodiment B. This is a cross-sectional view showing an electrostatic chuck of Embodiment C. This is a cross-sectional view showing an electrostatic chuck of Embodiment D. This is a cross-sectional view showing an electrostatic chuck of Embodiment E. This is a cross-sectional view showing a modified version of the electrostatic chuck of Embodiment A. This is a cross-sectional view showing an electrostatic chuck of Embodiment F.

[0010] The present invention will be described below based on preferred embodiments. Note that the dimensional ratios of the components in the drawings may not necessarily be the same as those in reality.

[0011] Figure 1 schematically shows an example of an electrostatic chuck according to an embodiment. This electrostatic chuck 10 has a recess 12 in the mounting surface 11 and comprises one or more electrodes 13 arranged along the mounting surface 11, a base 14, and a dielectric layer 15 on which the electrodes 13 are laminated between the base 14 and the mounting surface 11. In Figure 1, the direction perpendicular to the mounting surface 11 is the up and down direction, and the direction parallel to the mounting surface 11 is the left and right direction.

[0012] The function of the electrode 13 can be selected from appropriate purposes in the electrostatic chuck 10, such as adsorption, control, or heating. The electrode 13 laminated on the dielectric layer 15 may be just one layer, or it may be two or more types or two or more layers. The electrode 13 is formed from a conductive material. The material of the electrode 13 is not particularly limited, but examples include metals such as copper, aluminum, gold, silver, platinum, chromium, nickel, yttrium, silicon, and tungsten, alloys containing at least one of these metals, and mixtures of these metals with ceramics (alumina, aluminum nitride, silicon carbide, diamond, yttrium oxide, etc.) containing at least one of these metals.

[0013] The material of the base 14 is not particularly limited, but examples include ceramics (alumina, aluminum nitride, silicon carbide, yttrium oxide, zirconium oxide, etc.), diamond, and metal. Examples of metals used for the base 14 include aluminum and stainless steel. For example, the base 14 may have a conductive layer (metal coating layer, etc.) formed on the ceramic base body (the surface on the electrode 13 side).

[0014] In another configuration, for example, a conductive layer may be provided between the electrode 13 and the ceramic base 14. The base 14 formed from metal, the conductive layer 14a formed on the ceramic base body, or the conductive layer (not shown) provided between the electrode 13 and the ceramic base 14 may also function as a control electrode. For example, these control electrodes are connected to a plasma power supply and function as lower electrodes in plasma generation.

[0015] The material of the dielectric layer 15 on which the electrodes 13 are laminated is not particularly limited, but examples include resins and ceramics. Two or more dielectric materials may be laminated or mixed to form a composite. Examples of resin layers include resin films and resin coatings. The resin layer may also contain additives other than resin, such as ceramic particles. The dielectric material may also contain an adhesive layer, an adhesion layer, etc. Examples of ceramic layers include sintered bodies, thermal spray films, and coating films.

[0016] The resin constituting the resin coating film or adhesive layer in the dielectric layer 15 is not particularly limited as long as it is electrically insulating, but from the viewpoint of heat resistance, examples include epoxy resin, phenolic resin, styrene-based block copolymer, polyamide resin, acrylonitrile-butadiene copolymer, polyester resin, polyimide resin, polyetherketone resin, fluororesin, silicone resin, amine compound, bismaleimide compound, etc. These resins may be used individually or in mixtures of two or more.

[0017] The resin material forming the resin film in the dielectric layer 15 is not particularly limited as long as it is electrically insulating, but from the viewpoint of heat resistance, examples include polyesters such as polyethylene terephthalate, polyolefins such as polyethylene, polyimide, polyamide, polyamide-imide, polyethersulfone, polyphenylene sulfide, polyetherketone, polyetherimide, triacetylcellulose, silicone rubber, and fluororesins such as polytetrafluoroethylene.

[0018] The materials constituting the ceramic layer in the dielectric layer 15 are not particularly limited, but examples include silicon carbide, aluminum oxide, yttrium oxide, hafnium oxide, boron nitride, aluminum nitride, zirconium oxide, silicon oxide, tin oxide, indium oxide, quartz glass, soda glass, lead glass, borosilicate glass, zirconium nitride, titanium oxide, etc. These ceramic materials may be used individually or in combination of two or more.

[0019] An intermediate layer (adhesion layer 17) containing at least one of an organic insulating resin or an inorganic insulating resin may be laminated between the dielectric layer 15, such as a resin layer, and the ceramic layer 16 having a mounting surface 11. The organic insulating resin is not particularly limited, but examples include polyimide resins, epoxy resins, and acrylic resins. The inorganic insulating resin is not particularly limited, but examples include silane resins and silicone resins. Here, "organic insulating resin" refers to a polymer material containing carbon in its main chain, while "inorganic insulating resin" refers to a polymer material not containing carbon in its main chain.

[0020] The intermediate layer (adhesion layer 17) may contain at least one of the following: organic or inorganic polysilazane, inorganic powdered filler, and fibrous filler. Examples of powdered fillers are not particularly limited, but include silica, quartz, alumina, calcium carbonate, magnesium oxide, diamond, mica, fluororesin, zircon, etc. Examples of fibrous fillers are not particularly limited, but include plant fibers such as pulp, inorganic fibers such as alumina, and organic fibers such as aramid and polytetrafluoroethylene.

[0021] The embodiments of this disclosure are described below in detail, but are not limited thereto. For example, the electrostatic chuck 10 in Figure 1 is the same or similar component as the electrostatic chucks 10A, 10A2, 10B, 10C, 10D, 10E, and 10F in Figures 2 to 8. In addition, in particularly preferred embodiments, the same or similar components may be given different names. For example, the mounted member 30 is the same or similar component as the wafer and edge ring. These descriptions are omitted as appropriate.

[0022] In the illustrated example of the electrostatic chuck 10, the electrode 13 may be laminated between the resin film 15b together with the adhesive layer 15a, and a ceramic layer 16 may be laminated via an adhesion layer 17. The adhesive layer 15a may be interposed between the electrode 13 and the resin film 15b, or the electrode 13 may be laminated on the resin film 15b without the adhesive layer 15a. The resin film 15b of the dielectric layer 15 and the base 14 may be bonded together with an adhesive layer 18.

[0023] The resin constituting the adhesive layer 18 and / or the resin layer 20 is not particularly limited as long as it is electrically insulating, but examples include epoxy resin, phenolic resin, styrene block copolymer, polyolefin resin, polyamide resin, acrylonitrile-butadiene copolymer, polyester resin, polyimide resin, polyamideimide resin, acrylic resin, silicone resin, fluororesin, amine compound, bismaleimide compound, etc. These resins may be used individually or mixed together. The adhesive layer 15a, adhesive layer 18, and resin layer 20 may be made of the same type of resin, or they may be made of different resins.

[0024] Furthermore, it is preferable that the mounting surface 11 including the recess 12 be formed from a ceramic layer 16. The ceramic layer 16 including the recess 12 may include a ceramic underlayer formed over the entire surface on the adhesion layer 17 and a ceramic surface layer partially formed on the ceramic underlayer. In this case, the area on the ceramic underlayer where the ceramic surface layer is not formed can be made into the recess 12.

[0025] A ceramic layer 16 having a mounting surface 11 can also be formed from a ceramic plate. A recess 12 can be formed on the mounting surface 11 side of the ceramic plate, and an adhesive layer 17 can be laminated on the dielectric layer 15 side to bond it to the dielectric layer 15. The adhesive layer 17 that adheres the ceramic plate to the dielectric layer 15 may be an adhesive sheet similar to the adhesive layer 15a.

[0026] The electrostatic chuck 10 of this embodiment has a region where the recess 12 and the electrode 13 overlap in a plan view taken from a direction perpendicular to the mounting surface 11. The region where the recess 12 and the electrode 13 overlap corresponds to the regions of lengths L1 and L2. In the illustrated example, the region where the recess 12 and the electrode 13 overlap is located on both sides of the recess 12 in a direction parallel to the mounting surface 11, but it may be on at least one side. In the illustrated example, the length of the region where the recess 12 and the electrode 13 overlap is the sum of lengths L1 and L2. Length L3 is the length of the recess 12. Length L4 is the distance (spacing) between the electrodes 13.

[0027] The recess 12 holds gas between itself and the member 30 placed on the mounting surface 11. As will be described in more detail later, the recess 12 may also be a groove. The gas may be the ambient gas present around the electrostatic chuck 10, or a cooling gas (temperature control gas) used to cool the mounted member 30, etc. Examples of these gases include air, nitrogen, and argon.

[0028] The base 14 includes a metal such as aluminum. For example, the entire base 14 may be made of metal, or a conductive layer 14a may be laminated on the surface of the base 14. An example of the conductive layer 14a is a metal coating layer. If the entire base 14 is made of metal, the conductive layer 14a may be omitted. In Figure 1, the thickness of the conductive layer 14a is omitted, and only the position of the conductive layer 14a is shown. In the following description, when applying a voltage to the base 14, if the base 14 includes a ceramic body and a conductive layer 14a, it is not necessary to apply a voltage to the ceramic body; it is sufficient to apply a voltage to the conductive layer 14a. Also, even if the base 14 is a conductor such as metal, the voltage may be applied only to the surface of the conductor due to the skin effect, for example.

[0029] When a high voltage is applied to the base 14, the electric field generated in the base 14 spreads in a direction perpendicular to the mounting surface 11. If cooling gas is held between the member 30 placed on the mounting surface 11 and the recess 12, the electric field generated in the base 14 affects the cooling gas, which has a low withstand voltage, and there is a risk of spatial discharge occurring in the recess 12. At this time, by providing an electrode 13 between the recess 12 and the base 14 and securing an overlapping area between the recess 12 and the electrode 13, the risk of spatial discharge can be reduced. This is because the electrode 13 shields the electric field generated from the base 14 toward the recess 12, reducing the electric field generated in the base 14 that affects the recess 12, and as a result, spatial discharge within the recess 12 is suppressed. This makes it possible to provide an electrostatic chuck 10 with good electrical characteristics. Here, it is preferable that the power supply connected to the base 14 is an AC power supply.

[0030] In a plan view taken from a direction parallel to the mounting surface 11, it is preferable that the length of the region where the recess 12 and the electrode 13 overlap is 5% or more of the length of the recess 12. By having the length of the region where the recess 12 and the electrode 13 overlap be greater than or equal to the lower limit, spatial discharge can be suppressed more reliably, and as a result, an electrostatic chuck with good electrical characteristics can be provided. The upper limit is not particularly limited, but the length of the region where the recess 12 and the electrode 13 overlap may be 100% or less, 70% or less, 50% or less, etc., of the length of the recess 12.

[0031] The recess 12 may be a groove. Also, as shown in the illustrated example, the recess 12 may be an annular groove (circular, polygonal annular, C-shaped, or one or more intermittently provided arcs). In Figure 1, the structure is rotationally symmetric about the axis of symmetry A, and the recess 12 is an annular shape about the axis of symmetry A. When a groove is provided along the outer circumference of the mounting surface, the groove may be a single circle in the radial direction, or there may be two or more parallel grooves. The cross-sectional shape of the groove-shaped recess 12 is not particularly limited, but examples include semicircular, triangular, trapezoidal, rectangular (rectangular or square). The corners of the bottom surface of the groove-shaped recess 12 or the corners in contact with the mounting surface 11 may be rounded.

[0032] If the recess 12 is not a groove, it may be a localized recess. For example, the diameter of the recess 12 may be within 1%, 5%, 10%, or 20% of the diameter of the mounting surface 11, respectively. In a plan view from a direction perpendicular to the mounting surface 11, the planar shape of the localized recess 12 is not particularly limited, but examples include circular, elliptical, polygonal, etc. Examples of polygonal planar shapes include triangles, squares, pentagons, hexagons, etc. In the case of a polygonal planar shape, the length of the longest diagonal of the polygon may be used as the diameter, and the corners of the polygon in plan view may be rounded. The cross-sectional shape of the localized recess 12 is not particularly limited, but examples include semicircular, triangular, trapezoidal, rectangular (rectangular or square) shapes. The corners of the bottom surface of the localized recess 12 or the corners in contact with the mounting surface 11 may be rounded.

[0033] In the annular groove, the groove may be continuous around the entire circumference in a plan view, or it may have sections where the groove is divided in a C-shape. The circumferential spacing of the sections where the groove is divided in a C-shape may be within 1%, 5%, 10%, 20%, etc., relative to the diameter of the mounting surface. The width of the annular groove may be, for example, within 1%, 5%, 10%, 20%, etc., relative to the diameter of the mounting surface. If the outer circumference of the mounting surface is circular, the annular groove may be provided in a shape approximately similar to the outer circumference of the mounting surface. In addition, multiple arc-shaped grooves may be formed intermittently in the annular groove. The central angle of each arc-shaped groove can be, for example, 60 to 180°. Specific examples include combinations such as three arc-shaped sections with a central angle of approximately 100 to 120°, or four arc-shaped sections with a central angle of approximately 70 to 90°.

[0034] The polygonal annular groove may be formed in an annular shape along the contour of a polygon, such as a quadrilateral, in plan view. If the outer periphery of the mounting surface is polygonal, the polygonal annular groove may be formed in a manner substantially similar to the outer periphery of the mounting surface. The polygonal annular groove may be continuous around the entire circumference of the polygonal contour, or it may have sections where the groove is divided in a substantially C-shape. Linear grooves (divided at the corners of the polygon) may be provided on each side of the polygonal contour, or substantially L-shaped grooves (divided in the middle of the sides of the polygon) may extend on both sides of the corners of the polygon. The width of the polygonal annular groove may be, for example, within 1%, within 5%, within 10%, within 20%, etc., of the diameter of the mounting surface. If the outer periphery of the mounting surface 11 is polygonal, the length of the longest diagonal of the polygon may be used as the diameter of the mounting surface 11, and the corners of the polygon may be rounded.

[0035] It is preferable that the recess 12 is provided with a groove, and it is more preferable that the groove is provided continuously or intermittently. This ensures that the placed member 30 is uniformly temperature-controlled and uniform electrical properties are obtained within the placement surface 11. As a result, an electrostatic chuck 10 with good thermal uniformity and electrical properties can be provided. The depth of the recess 12 is not particularly limited, but for example, it can be 0.05 mm or less. This ensures that sufficient capacitance is obtained to attract the placed member 30, and as a result, an electrostatic chuck 10 with good attraction force and electrical properties can be provided.

[0036] The electrode 13 may consist of multiple electrodes 13. In the illustrated example, in the region where the recess 12 and the electrode 13 overlap, the same recess 12 overlaps with multiple electrodes 13. This allows for more reliable suppression of discharge.

[0037] It is preferable that the electrode 13 overlaps with either the outer peripheral side wall 12o or the inner peripheral side wall 12i of the recess 12 (Figure 6), and it is more preferable that both the outer peripheral side wall 12o and the inner peripheral side wall 12i of the recess 12 overlap with the electrode 13 (Figure 2, etc.). In other words, since the electrode 13 overlaps with both the mounting surface 11 and the recess 12, spatial discharge in the recess 12 is suppressed, and at the same time, sufficient capacitance necessary to attract the mounted member 30 is obtained, and as a result, the electrostatic chuck 10 can achieve both attractive force and electrical characteristics.

[0038] The electrodes 13 may be a plurality of electrodes 13 arranged on the same plane. Preferably, the shortest distance between the plurality of electrodes 13 is 10 to 3000 μm. Preferably, the lower limit of the shortest distance between the electrodes 13 is set from the viewpoint of ensuring electrical insulation between the electrodes 13. Preferably, the upper limit of the shortest distance between the electrodes 13 is set from the viewpoint of ensuring an area of ​​electrodes 13 that contributes to the adsorption of the placed member 30.

[0039] It is preferable that the shortest distance between the mounting surface 11 and the electrode 13 is 10 to 500 μm. The shortest distance between the mounting surface 11 and the electrode 13 is preferably set from the viewpoint of ensuring electrical insulation. The upper limit of the shortest distance between the mounting surface 11 and the electrode 13 is preferably set from the viewpoint of ensuring the capacitance necessary to attract the mounted member 30.

[0040] It is preferable that the electrical resistivity of the member 30 placed on the mounting surface 11 is equivalent to that of a semiconductor member or a conductive member. For example, the electrical resistivity of a conductor is 10 －８ ~10 －４ It can also be expressed as Ω·cm, and the electrical resistivity of a semiconductor is 10 －４ ~10 ８ It may also be Ω·cm. The shape of the member 30 placed on the mounting surface 11 may be ring-shaped. The member 30 placed on the mounting surface 11 is not particularly limited, but examples include semiconductor substrates, edge rings, etc.

[0041] An earth retaining part 19 is provided on the outer periphery of the mounting surface 11, and the end of the earth retaining part 19 may have a curved surface. By providing the earth retaining part 19 on the outer periphery, the capacitance with respect to the member 30 to be mounted is stabilized, and the member 30 to be mounted can be adsorbed more reliably.

[0042] In a plan view seen from a direction parallel to the mounting surface 11, the ratio of the length of the electrode 13 to the length of the mounting surface 11 is preferably 0.5 or more and 1.0 or less, and more preferably 0.7 to 1.0. The lower limit value of the ratio of the length of the electrode 13 to the length of the mounting surface 11 is preferably set from the viewpoint of ensuring the capacitance for reliably adsorbing the member 30 mounted on the mounting surface 11. The upper limit value of the ratio of the length of the electrode 13 to the length of the mounting surface 11 is preferably set from the viewpoint of ensuring electrical insulation around the electrode 13 or between the electrodes 13.

[0043] In a plan view seen from a direction parallel to the mounting surface 11, the ratio of the length of the bottom surface of the concave portion 12 to the length of the mounting surface 11 is preferably 0.10 or more and 0.67 or less, and more preferably 0.33 to 0.50. The lower limit value of the ratio of the length of the bottom surface of the concave portion 12 to the length of the mounting surface 11 is preferably set from the viewpoint of uniformly regulating the temperature of the member 30 mounted on the mounting surface 11. The upper limit value of the ratio of the length of the bottom surface of the concave portion 12 to the length of the mounting surface 11 is preferably set from the viewpoint of ensuring the capacitance for reliably adsorbing the member 30 mounted on the mounting surface 11.

[0044] <Embodiment A> Figure 2 shows an example of the electrostatic chuck of Embodiment A. In Figure 2, a second electrostatic chuck for holding an edge ring will be described, but it is not limited thereto.

[0045] The electrostatic chuck 10A of Embodiment A includes a first electrostatic chuck having a first mounting surface 11 at the center and a second electrostatic chuck having a second mounting surface 11 on the outer periphery of the mounting surface 11 in a vertical field of view with respect to the mounting surface 11. For example, a wafer or the like is held on the first mounting surface 11, and an edge ring is held on the second mounting surface 11. In the direction perpendicular to the mounting surface 11, the second mounting surface 11 is located between the first mounting surface 11 and the lower surface of the base 14.

[0046] The electrostatic chuck 10A of Embodiment A includes one or more first electrodes 13 arranged along the first mounting surface 11, a first conductive layer 14a (first lower electrode) provided on the base 14, and a first dielectric layer 15 in which the first electrodes 13 are laminated between the base 14 and the first mounting surface 11 (first electrostatic chuck). Further, the electrostatic chuck 10A of Embodiment A includes one second electrode 13 arranged along the second mounting surface 11, a second conductive layer 14a (second lower electrode) provided on the base 14, and a second dielectric layer in which the second electrode 13 is laminated between the base 14 and the second mounting surface 11, and the second mounting surface 11 has a recess 12 (second electrostatic chuck).

[0047] In a direction-of-view perpendicular to the second mounting surface 11, the recess 12 is entirely included in the second electrode 13. As a result, the second electrode 13 can shield the entire electric field generated from the second lower electrode of the base 14 toward the recess 12, so that the electric field generated in the second lower electrode of the base 14 that affects the recess 12 is reduced. As a result, partial discharge in the recess 12 is suppressed. As a result, an electrostatic chuck 10A with good electrical characteristics can be provided. In FIG. 2, the direction perpendicular to the mounting surface 11 is the vertical direction, and the direction parallel to the mounting surface 11 is the horizontal direction.

[0048] The first mounting surface 11, the second mounting surface 11, the first electrode 13, the second electrode 13, the first dielectric layer 15, the second dielectric layer 15, the recess 12, the wafer, and the edge ring can use the same configurations as the above-described mounting surface 11, electrode 13, dielectric layer 15, recess 12, and member 30 to be mounted.

[0049] <Embodiment B>FIG. 3 shows an example of the electrostatic chuck of Embodiment B. Although the second electrostatic chuck (for details, refer to the description of Embodiment A) in which the edge ring is held will be described in FIG. 3, the present invention is not limited thereto. In a direction-of-view perpendicular to the second mounting surface 11, the second mounting surface 11 is located between the first mounting surface and the lower surface of the base 14.

[0050] The electrostatic chuck 10B of Embodiment B includes a plurality of second electrodes 13 (for example, second electrodes 13a, 13b) arranged along a second mounting surface 11, a second conductive layer 14a (second lower electrode) provided on a base 14, and a second dielectric layer 15 on which the second electrodes 13 are laminated between the base 14 and the second mounting surface 11, and has a recess 12 on the second mounting surface 11. In a field of view perpendicular to the second mounting surface 11, the recess 12 overlaps with a part of the second electrode 13a and a part of the second electrode 13b, and the recess 12 does not overlap with the second electrode 13 between the second electrode 13a and the second electrode 13b. In other words, in a field of view perpendicular to the second mounting surface 11, a part of the recess 12 does not overlap with the second electrode 13, but the outer peripheral sidewall and inner peripheral sidewall of the recess 12 overlap with the second electrode 13. As a result, the second electrode 13 can partially shield the electric field generated from the second lower electrode of the base 14 toward the recess 12, thereby reducing the electric field generated at the second lower electrode of the base 14 that affects the recess 12, and consequently suppressing spatial discharge within the recess 12. As a result, an electrostatic chuck 10B with good electrical characteristics can be provided.

[0051] <Embodiment C> Figure 4 shows an example of an electrostatic chuck according to Embodiment C. Figure 4 describes a second electrostatic chuck that holds the edge ring (see the description of Embodiment A for details), but is not limited to this. In a field of view perpendicular to the second mounting surface 11, the second mounting surface 11 is located between the first mounting surface and the lower surface of the base 14.

[0052] The second electrostatic chuck provided in the electrostatic chuck 10C of Embodiment C comprises a plurality of second electrodes 13 (for example, second electrodes 13a, 13b, 13c) arranged along the second mounting surface 11, a second conductive layer 14a (second lower electrode) provided on the base 14, and a second dielectric layer 15 on which the second electrodes 13 are laminated between the base 14 and the second mounting surface 11, and has a recess 12 on the second mounting surface 11. In a field of view perpendicular to the second mounting surface 11, the recess 12 overlaps with the entirety of the central second electrode 13b, and the recess 12 does not overlap with the left and right second electrodes 13a, 13c. In other words, in a direction perpendicular to the second mounting surface 11, the recess 12 overlaps with the second electrode 13, but the outer peripheral sidewall and inner peripheral sidewall of the recess 12 do not overlap with the second electrode 13. More specifically, the positions of the outer and inner side walls of the recess 12 overlap the regions between the left and right second electrodes 13a and 13c and the central second electrode 13b, respectively. As a result, the second electrode 13 can partially shield the electric field generated from the second lower electrode of the base 14 toward the recess 12, thereby reducing the electric field generated at the second lower electrode of the base 14 that affects the recess 12, and consequently suppressing spatial discharge within the recess 12. As a result, an electrostatic chuck 10C with good electrical characteristics can be provided.

[0053] <Embodiment D> Figure 5 shows an example of an electrostatic chuck according to Embodiment D. Figure 5 describes a second electrostatic chuck that holds the edge ring (see the description of Embodiment A for details), but is not limited to this. In a field of view perpendicular to the second mounting surface 11, the second mounting surface 11 is located between the first mounting surface and the lower surface of the base 14.

[0054] The electrostatic chuck 10D of Embodiment D includes a plurality of second electrodes 13 (for example, second electrodes 13a, 13b) arranged along a second mounting surface 11, a second conductive layer 14a (second lower electrode) provided on a base 14, and a second dielectric layer 15 on which the second electrodes 13 are laminated between the base 14 and the second mounting surface 11, and has a recess 12 on the second mounting surface 11. In a field of view perpendicular to the second mounting surface 11, all of the recess 12 overlap with the left second electrode 13a, and the recess 12 does not overlap with the right second electrode 13b. For example, as shown in Figure 5, the recess 12 is unevenly distributed on either the outer or inner circumference side of the second mounting surface 11, and the recess 12 overlaps with only either the second electrode 13a or the second electrode 13b. As a result, the second electrode 13 can shield the entire electric field generated from the second lower electrode of the base 14 toward the recess 12, thereby reducing the electric field generated at the second lower electrode of the base 14 that affects the recess 12, and consequently suppressing spatial discharge within the recess 12. As a result, an electrostatic chuck 10D with good electrical characteristics can be provided.

[0055] <Embodiment E> Figure 6 shows an example of an electrostatic chuck according to Embodiment E. Figure 6 describes a second electrostatic chuck that holds the edge ring (see the description of Embodiment A for details), but is not limited to this. In a field of view perpendicular to the second mounting surface 11, the second mounting surface 11 is located between the first mounting surface and the lower surface of the base 14.

[0056] The second electrostatic chuck provided in the electrostatic chuck 10E of Embodiment E comprises one or more electrodes 13 arranged along the second mounting surface 11, a second conductive layer 14a (second lower electrode) provided on the base 14, and a second dielectric layer 15 on which the second electrode 13 is laminated between the base 14 and the second mounting surface 11, and has a recess 12 on the second mounting surface 11. In a field of view perpendicular to the second mounting surface 11, a part of the recess 12 overlaps with the second electrode 13, and another part of the recess 12 does not overlap with the second electrode 13. In other words, in a direction perpendicular to the second mounting surface 11, only one of the outer peripheral sidewall or the inner peripheral sidewall of the recess 12 overlaps with the second electrode 13. As a result, the second electrode 13 can partially shield the electric field generated from the second lower electrode of the base 14 toward the recess 12, thereby reducing the electric field generated at the second lower electrode of the base 14 that affects the recess 12, and consequently suppressing spatial discharge within the recess 12. As a result, an electrostatic chuck 10E with good electrical characteristics can be provided.

[0057] <Modification of Embodiment A> Figure 7 shows a modification of the electrostatic chuck of Embodiment A. Figure 7 describes a second electrostatic chuck in which the edge ring is held (see the description of Embodiment A for details), but is not limited to this. It is the same as Embodiment A except that the width of the second electrode 13 is shorter than the width of the recess 12 in a field of view perpendicular to the second mounting surface 11.

[0058] Furthermore, in a field of view parallel to the mounting surface 11, it is preferable that the length La between the mounting surface 11 and the electrode 13 is less than or equal to half the length Lb between the base 14 and the electrode 13. By keeping the electrode 13 and the mounting surface 11 close in this way, sufficient capacitance is ensured to reliably attract the member 30 placed on the mounting surface 11, and as a result, an electrostatic chuck with good electrical characteristics and adsorption performance can be provided.

[0059] This configuration, in which the distance between the electrode 13 and the mounting surface 11 is short (La ≤ Lb / 2), is not limited to the modification of Embodiment A, but can be applied to all other embodiments (including Embodiments B, C, D, E, and F), and is applicable not only to electrostatic chucks for edge rings, but also to electrostatic chucks for wafers and other types of electrostatic chucks.

[0060] <Embodiment F> Figure 8 shows an example of an electrostatic chuck according to Embodiment F. Figure 8 describes a second electrostatic chuck that holds the edge ring (see the description of Embodiment A for details), but is not limited to this. In a field of view perpendicular to the second mounting surface 11, the second mounting surface 11 is located between the first mounting surface and the lower surface of the base 14.

[0061] The electrostatic chuck 10F of Embodiment F includes a plurality of second electrodes 13 (for example, second electrodes 13a, 13b) arranged along the second mounting surface 11, a second conductive layer 14a (second lower electrode) provided on the base 14, and a second dielectric layer 15 on which the second electrodes 13 are laminated between the base 14 and the second mounting surface 11, and has a plurality of recesses 12 (for example, recesses 12a, recesses 12b) on the second mounting surface 11. In a field of view perpendicular to the second mounting surface 11, the recesses 12a and 12b overlap with the second electrodes 13. The number of recesses is not particularly limited as long as it is two or more. For example, as shown in Figure 8, each of the recesses 12a and 12b may overlap with each of the second electrodes 13a and 13b. In this case, the second electrode 13 can shield the entire electric field generated from the second lower electrode of the base 14 toward the recess 12, thereby reducing the electric field generated at the second lower electrode of the base 14 that affects the recess 12, and as a result, spatial discharge within the recess 12 is suppressed. As a result, an electrostatic chuck 10F with good electrical characteristics can be provided.

[0062] (Method for manufacturing an electrostatic chuck) Next, the method for manufacturing the electrostatic chuck of this embodiment will be described.

[0063] A thin metal film, such as copper, is formed by depositing a metal onto the surface of the resin film 15b (the upper surface in the thickness direction of the resin film 15b). Subsequently, etching is performed to pattern the thin metal film into a predetermined shape to form the electrode 13. The electrode 13 can be formed not only by metal deposition (vacuum plating), but also by wet plating of metal, adhesion of metal foil, etc. If the electrostatic chuck has a first electrode 13 and a second electrode 13 (see embodiments A to F), the first electrode 13 and the second electrode 13 can be formed on the surface of the same resin film 15b.

[0064] Next, a resin film 15b is attached to the upper surface of the electrode 13 via an adhesive layer 15a to form a laminate. This laminate can have a laminated structure of dielectric layers 15 on which the electrodes 13 are stacked.

[0065] Next, a first laminate containing the first electrode 13 and a second laminate containing the second electrode 13 are cut from the laminate containing the first electrode 13 and the second electrode 13 to match the size of the central portion and the outer circumference of the base 14. Then, these laminates are joined to the central portion and the outer circumference of the base 14 via a first adhesive layer and a second adhesive layer.

[0066] Next, an adhesion layer 17 is formed to cover the entire outer surface of the base 14, the first laminate, and the second laminate. The method for forming the adhesion layer 17 is not particularly limited, as long as it covers the entire outer surface of the base 14, the first laminate, and the second laminate. Examples of methods for forming the adhesion layer 17 include bar coating, spin coating, and spray coating.

[0067] Next, a ceramic underlayer is formed so as to cover the entire outer surface of the adhesion layer 17. Methods for forming the ceramic underlayer include, for example, applying a slurry containing the material constituting the ceramic underlayer to the entire outer surface of the adhesion layer 17 and sintering it to form the ceramic underlayer, or thermal spraying the material constituting the ceramic underlayer to the entire outer surface of the adhesion layer 17 to form the ceramic underlayer. Here, thermal spraying is a method of forming a film by heating and melting the material that will become the coating (in this embodiment, the ceramic underlayer) and then injecting it onto the object to be treated using compressed gas. The ceramic underlayer may be located below the ceramic layer 16, particularly below the recess 12.

[0068] Next, a ceramic surface layer is formed on the upper surface of the ceramic base layer. Methods for forming the ceramic surface layer include, for example, a method in which a mask of a predetermined shape is applied to the upper surface a of the ceramic base layer, and then the material constituting the ceramic surface layer is sprayed onto the upper surface of the ceramic base layer to form the ceramic surface layer; or a method in which the material constituting the ceramic surface layer is sprayed onto the entire upper surface of the ceramic base layer to form the ceramic surface layer, and then the ceramic surface layer is shaved down by blasting to form an uneven ceramic surface layer. Here, by applying the mask of a predetermined shape, any recess 12 can be formed. The ceramic surface layer may be the upper layer of the ceramic layer 16, especially the upper layer including the mounting surface 11 in the area without the recess 12.

[0069] By following the above steps, the electrostatic chuck 10 of this embodiment can be manufactured.

[0070] As mentioned above, the ceramic layer 16 may be a ceramic plate attached to the dielectric layer 15 via the adhesion layer 17. In this case, the steps for forming the adhesion layer 17 and the ceramic layer 16 differ from those described above.

[0071] When forming the ceramic layer 16 from a ceramic plate, the steps of forming the adhesive layer 18 on the base 14 side of the dielectric layer 15 and forming the adhesion layer 17 on the mounting surface 11 side of the dielectric layer 15 may be combined. For example, the dielectric layer 15 and the adhesive layer 18 may be formed by attaching adhesive sheets to both sides of a first laminate and a second laminate, each consisting of a dielectric layer 15 including electrodes 13. When forming the dielectric layer 15 and the adhesive layer 18, the adhesive sheets may be cured simultaneously.

[0072] Although the present invention has been described above based on preferred embodiments, the present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention.

[0073] The present invention will be specifically described below with reference to examples.

[0074] [Example 1] As the resin film 15b, a polyimide film (product name: Kapton, manufactured by Toray DuPont) with a thickness of 12.5 μm was plated with copper to a thickness of 9 μm on one side. After applying a photoresist to the surface of the copper plating (or copper foil), a development process was performed after pattern exposure, and the unwanted copper foil was removed by etching. Subsequently, the photoresist was removed by washing the copper foil on the polyimide film, and the first electrode 13 and the second electrode 13 were formed. A curable adhesive sheet (electrode attachment adhesive sheet) was laminated on the first electrode 13 and the second electrode 13. As the adhesive sheet, 27 parts by mass of bismaleimide resin, 3 parts by mass of diaminosiloxane, 20 parts by mass of resolphenol resin, 10 parts by mass of biphenyl epoxy resin, and 240 parts by mass of ethyl acrylate-butyl acrylate-acrylonitrile copolymer were mixed and dissolved in an appropriate amount of tetrahydrofuran, formed into a sheet, and the tetrahydrofuran was dried. Subsequently, a laminate was obtained by bonding the same polyimide film (another resin film 15b) as the resin film 15b on which the electrodes were formed, and then adhering it by heat treatment. The adhesive sheet for electrode attachment hardened by heat treatment, forming an adhesive layer 15a between the resin films 15b that sandwiched the electrodes 13. The thickness of the adhesive layer 15a was 20 μm.

[0075] Furthermore, a first laminate (circular, 296 mm in diameter) and a second laminate (ring-shaped, 350 mm outer diameter, 298 mm inner diameter) were cut from the laminate. A curable adhesive sheet (base attachment adhesive sheet), the same as the electrode attachment adhesive sheet described above, was prepared in the same size as the first and second laminates and laminated onto the surfaces of the polyimide film on the first and second laminates that were opposite to the surfaces on which the first and second electrodes 13 were formed. Subsequently, the first and second laminates were attached to an aluminum base 14 (at positions corresponding to the first and second mounting surfaces 11 and 2 mounting surfaces 11 formed on the ceramic layer 16 described later) and bonded by heat treatment. In a field of view perpendicular to the mounting surface 11, the circular first laminate and the ring-shaped second laminate are arranged concentrically, with the first laminate positioned inside the inner diameter of the second laminate. Furthermore, in a field of view perpendicular to the second mounting surface 11, the second mounting surface 11 is located between the first mounting surface 11 and the lower surface of the base 14, and is 1.0 mm away from the first mounting surface 11. The adhesive sheet for base attachment was cured by heat treatment, forming an adhesive layer 18 between the base 14 and the first and second laminates. The thickness of the adhesive layer 18 was 10 μm.

[0076] Next, 100 parts by mass of polysilazane and 200 parts by mass of an inorganic filler (average particle size: 3 μm) consisting of alumina were mixed in butyl acetate as a diluent, and the inorganic filler was then uniformly dispersed using an ultrasonic disperser to produce a paint.

[0077] Next, the paint was sprayed onto the entire outer surface of the base 14, the first laminate, and the second laminate, and then heated and dried to form an intermediate layer (adhesion layer 17). The thickness of the intermediate layer on the entire outer surface of the base 14, the first laminate, and the second laminate was 10 μm.

[0078] Next, alumina powder (average particle size: 8 μm) was sprayed onto the entire surface of the intermediate layer using a plasma spraying method to form a ceramic underlayer with a thickness of 50 μm.

[0079] Next, after applying a mask of a predetermined shape to the surface of the ceramic base layer, the alumina powder (average particle size: 8 μm) was thermal sprayed onto the surface of the ceramic base layer to form a ceramic surface layer with a thickness of 15 μm.

[0080] Next, the adsorption surface of the ceramic surface layer that adsorbs the adsorbed material was planar ground with a diamond grinding wheel to form a ceramic layer 16 having a first mounting surface 11 and a second mounting surface 11, thereby obtaining the electrostatic chuck device of Example 1. The dimensions of these electrostatic chuck devices are shown in Table 1. Furthermore, the surface roughness Ra of these electrostatic chuck devices was measured according to JIS B0601-1994 and found to be 0.3 μm.

[0081] [Examples 2-12, 15-20, Comparative Example 1] Similar to Example 1, electrostatic chuck devices for Examples 2-12 and 15-20 were manufactured to have the configurations shown in Tables 1-4. In Comparative Example 1, the electrostatic chuck device was manufactured to have the configuration shown in Table 4, except that the electrodes were omitted. The surface roughness Ra of each electrostatic chuck device was measured according to JIS B0601-1994 and found to be 0.3 μm.

[0082] In each dimension shown in Tables 1 to 4, the "length between the outer edge of the mounting surface and the recess" is the length from the outer edge of the mounting surface to the outer side wall of the recess, excluding the recess, and the "length between the inner edge of the mounting surface and the recess" is the length from the inner edge of the mounting surface to the inner side wall of the recess, excluding the recess. Furthermore, the "length between the inner edge of the mounting surface and the first electrode" is the length from the inner edge of the mounting surface to the inner side wall of the first electrode, excluding the first electrode, and the "length between the outer edge of the mounting surface and the second electrode" is the length from the outer edge of the mounting surface to the outer side wall of the second electrode, excluding the second electrode. Furthermore, the "length between each electrode" is the length from the outer side wall of the first electrode to the inner side wall of the second electrode. In addition, "sum of overlapping lengths between the recess and each electrode / length of the recess" and "length of the mounting surface excluding the recess / length of the mounting surface including the recess" are the ratios of the numerator to the denominator. The "length of the mounting surface including the recess" is the sum of the "length of the mounting surface excluding the recess" and the "length of the recess." Also, the "height from the bottom of the recess to the mounting surface" corresponds to the "depth of the recess."

[0083] [Examples 13 and 14] Except for the formation of the ceramic layer 16 (ceramic underlayer and ceramic surface layer), the electrostatic chuck devices of Examples 13 and 14 were manufactured in the same manner as in Example 1, so as shown in Table 3.

[0084] Specifically, the aforementioned adhesive sheets were laminated to both sides of the first laminate (circular, 296 mm in diameter) and the second laminate (ring-shaped, 350 mm outer diameter, 298 mm inner diameter) cut from the laminate. As for the adhesive sheets, an adhesive sheet for forming an adhesion layer was used on the mounting surface 11 side, and an adhesive sheet for attaching to the base was used on the base 14 side. These sheets were laminated to the side of the resin film 15b (polyimide film) on both sides of each laminate that was opposite to the side on which the electrode 13 was formed.

[0085] Next, the surface of the adhesive sheet for forming the adhesion layer was attached to the first alumina plate (circular, 296 mm in diameter, 1 mm thick) and the second alumina plate (ring-shaped, 350 mm in outer diameter, 298 mm in inner diameter), and the surface of the adhesive sheet for base attachment was attached to the aluminum base 14 (at positions corresponding to the first mounting surface 11 and the second mounting surface 11 formed on the ceramic layer 16 described later). After that, the sheets were bonded by heat treatment. The adhesive sheets hardened by the heat treatment, forming an adhesion layer 17 and an adhesive layer 18, respectively. The thickness of the adhesion layer 17 and the adhesive layer 18 was 10 μm.

[0086] The first alumina plate and the second alumina plate correspond to the first mounting surface 11 and the second mounting surface 11 of the ceramic layer 16, respectively, and have recesses 12 at appropriate positions on the mounting surface 11. Therefore, the electrostatic chuck devices of Examples 13 to 15 were manufactured by attaching the laminate to the base 14 and attaching the ceramic plates to the laminate. The surface roughness Ra of each of these electrostatic chuck devices was measured according to JIS B0601-1994 and found to be 0.3 μm.

[0087] (Evaluation of Discharge Prevention) The discharge prevention of the electrostatic chuck devices of Example 1 shown in Table 1 and Comparative Example 1 shown in Table 4 was evaluated. Specifically, a silicon (Si) edge ring (outer diameter 350 mm × inner diameter 297 mm × thickness 1.0 mm) was placed on the mounting surface of each electrostatic chuck device, and the edge ring and electrode were connected to GND. Then, the high-voltage side of an AC power supply (voltage ±5 kV, frequency 60 Hz) was connected to the base, and the maximum discharge charge amount was measured using a partial discharge tester (DAC-PD-3, manufactured by Soken Electric Co., Ltd.). Example 1 showed a maximum discharge charge amount of 38% compared to the maximum discharge charge amount obtained for Comparative Example 1. As a result, discharge suppression was confirmed.

[0088] (Evaluation of Heat Uniformity) As shown in Tables 1 to 4, the heat uniformity of the electrostatic chuck devices of Examples 1 to 20 was evaluated. Specifically, in the recess 12 of each electrostatic chuck device, six through holes (1.0 mmφ) were formed from the back surface of the base 14 to the recess 12, with equal spacing in the direction in which the ring of the recess 12 extends. Next, a silicon (Si) edge ring (outer diameter 350 mm × inner diameter 297 mm × thickness 1.0 mm) coated with blackbody paint (TASCO Corporation, blackbody spray TA410KS) to a thickness of 20 μm across the entire surface was placed on the mounting surface 11 of each electrostatic chuck device. Then, a DC high voltage of 3.0 kV was applied to the second electrode 13 to attract the edge ring. Subsequently, nitrogen gas was passed through each through-hole from the back side of the base 14 at 40°C using a polytetrafluoroethylene tube (outer diameter 1.0 mm, inner diameter 0.6 mm, length 100 mm) heated to 40°C, and flowed through each through-hole for 5 minutes at a flow rate of 1 mL / min. At this point, observation and measurement were performed using an infrared thermography camera (InfReC® R450Pro, manufactured by Avionics Japan Co., Ltd.), and the total area of ​​the edge rings where the measured temperature was within the range of 40°C ± 1°C was calculated and used for evaluation. These evaluations were performed under conditions of 25°C and 65% RH humidity. The evaluation criteria for uniform heat distribution were as follows: "A" if the ratio of the total area of ​​the edge rings where the surface temperature is within the range of 40°C ± 1°C to the total area of ​​the placed edge rings is 75% or more and 100% or less, "B" if it is 70% or more and less than 75%, "C" if it is 65% or more and less than 70%, and "D" if it is less than 65%.

[0089] (Evaluation of Adsorption Force) As shown in Tables 1 to 4, the adsorption force of the electrostatic chuck devices of Examples 1 to 20 was evaluated. Specifically, an aluminum plate (outer diameter 350 mm x inner diameter 297 mm x thickness 1.0 mm) was placed on each electrostatic chuck device, and the probe of an LCR meter (HIOKI Corporation, IM3536) was connected to the electrode and the aluminum plate with cables. Then, the capacitance was measured five times at 2-second intervals under a frequency condition of 1 kHz. This measurement was repeated five times, and the average value was used to evaluate the adsorption force (average capacitance). The evaluation criteria for the adsorption force were as follows: if the obtained average capacitance (in nF units) was 2.80 or higher, it was "A"; if it was 2.50 or higher and less than 2.80, it was "B"; if it was 1.00 or higher and less than 2.50, it was "C"; if it was less than 1.00, it was "D"; and if measurement was not possible, it was "X".

[0090]

[0091]

[0092]

[0093]

[0094] A comparison between Example 1 and Comparative Example 1 showed that the maximum discharge charge amount of Example 1, which had electrodes, could be significantly reduced compared to Comparative Example 1, which did not have electrodes. Furthermore, the evaluation results for Examples 1 to 20 showed excellent uniformity of heat and adsorption force. As a result, it was possible to manufacture an electrostatic chuck device with good electrical characteristics.

[0095] The present invention provides an electrostatic chuck with excellent electrical properties, such as discharge suppression and electrostatic characteristics.

[0096] A...axis of symmetry, 10, 10A, 10A2, 10B, 10C, 10D, 10E, 10F...electrostatic chuck, 11...mounting surface, 12, 12a, 12b...recess, 12i...inner circumferential side wall, 12o...outer circumferential side wall, 13, 13a, 13b, 13c...electrode, 14...base, 14a...conductive layer, 15...dielectric layer, 15a...adhesive layer, 15b...resin film, 16...ceramics layer, 17...adhesion layer, 18...adhesive layer, 19...ridge, 20...resin layer, 30...member to be mounted.

Claims

1. An electrostatic chuck having a recess on a mounting surface, comprising: one or more electrodes arranged along the mounting surface; a base; and a dielectric layer on which the electrodes are laminated between the base and the mounting surface, wherein, in a plan view taken from a direction perpendicular to the mounting surface, there is a region in which the recess and the electrodes overlap.

2. The electrostatic chuck according to claim 1, wherein the electrode is a plurality of electrodes, and in the region where the recess and the electrode overlap, the same recess overlaps with the plurality of electrodes.

3. In a plan view taken from a direction perpendicular to the mounting surface, the ends of one or more recesses overlap with one or more electrodes, as described in claim 1.

4. The electrostatic chuck according to claim 1, wherein the electrical resistivity of the member placed on the mounting surface is that of a semiconductor member or a conductive member.

5. The electrostatic chuck according to claim 1, wherein the recess is a groove.

6. The electrostatic chuck according to claim 1, wherein the recess is an annular groove.

7. The electrostatic chuck according to claim 1, wherein the shape of the member placed on the mounting surface is ring-shaped.

8. The electrostatic chuck according to claim 1, wherein a raised edge is provided on the outer circumference of the mounting surface, and a curved surface is provided at the end of the raised edge.

9. The electrostatic chuck according to claim 1, wherein the depth of the recess is 0.05 mm or less.

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