Electrostatic chuck

Abstract

To provide an electrostatic chuck in which the force applied from a conductive member to a power-receiving portion of a heater unit is not too large.SOLUTION: An electrostatic chuck 10 includes a heater unit 300 having a power-receiving portion 371, a conductive member 500 having a tip portion 511 that abuts against a power-receiving portion 371 by a restoring force from a compressed state, and a holding member 600 that holds the conductive member 500 in the compressed state. The holding member 600 holds the conductive member 500 with a rear end portion 524, which is the opposite side of the tip portion 511, of the conductive member 500, exposed to the outside. The electrostatic chuck 10 further includes an adjustment mechanism for adjusting the position of the rear end portion 524.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] For example, in a semiconductor manufacturing apparatus such as an etching apparatus, an electrostatic chuck is provided as a device for attracting and holding a substrate such as a silicon wafer to be processed. The electrostatic chuck includes a dielectric substrate provided with an attracting electrode and a base plate supporting the dielectric substrate, which are joined together. When a voltage is applied to the attracting electrode, an electrostatic force is generated, and the substrate placed on the dielectric substrate is attracted and held. When the substrate is being processed in the semiconductor manufacturing apparatus, the dielectric substrate is cooled by the base plate. This allows the temperature of the substrate placed on the dielectric substrate to be maintained at an appropriate temperature.

[0003] During the processing of a substrate, it is required to make the temperature distribution in the surface of the substrate as uniform as possible. In order to adjust the temperature distribution in the surface of the substrate with high accuracy, electrostatic chucks equipped with heaters have been developed in recent years and have already been put to practical use. The heater may be provided inside the dielectric substrate, or may be provided between the dielectric substrate and the base plate in a unitized state, as described in, for example, Patent Document 1 below. Considering that the dielectric substrate with a built-in heater can be regarded as a "heater unit" in its entirety, in either of the above cases, it can be said that the heater unit is joined to the base plate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6341457 Summary of the Invention [Problem to be solved by the invention]

[0005] For example, as described in the above Patent Document 1, power may be supplied to the heater unit via a conductive member that is in contact (without being fixed) with the power-supplied portion of the heater unit. In such a configuration, there is no need to protrude a terminal from the power-supplied portion of the heater unit in advance, and for example, the power-supplied portion and its surroundings can be made into flat surfaces, which makes it easier to assemble the electrostatic chuck including the heater unit.

[0006] The conductive member described in the above Patent Document 1 is an expandable contact probe, and its restoring force allows the tip to be pressed against the power-supplied part. However, if the restoring force of the conductive member becomes too large, excessive force is applied to the power-supplied part, which may cause deformation of the heater unit.

[0007] The present invention has been made in consideration of the above problems, and an object of the present invention is to provide an electrostatic chuck in which the force applied from a conductive member to a power-receiving portion of a heater unit is not too large. [Means for solving the problem]

[0008] In order to solve the above problems, an electrostatic chuck according to the present invention includes a heater unit having a power-receiving part that receives power from an outside, a conductive member whose tip end abuts against the power-receiving part by a restoring force from a compressed state, and a holding member that holds the conductive member in the compressed state. The holding member holds the conductive member with a rear end portion of the conductive member opposite to the tip end exposed to the outside. The electrostatic chuck further includes an adjustment mechanism for adjusting the position of the rear end portion.

[0009] In an electrostatic chuck having such a configuration, the state in which the tip end of the conductive member is in contact with the power-receiving portion of the heater unit can be maintained by the restoring force of the conductive member. Since there is no need to fix the heater unit and the conductive member by soldering or the like, the assembly work of the electrostatic chuck is easy. Furthermore, in the electrostatic chuck, the position of the rear end of the conductive member, i.e., the compressed state of the conductive member, can be adjusted by an adjustment mechanism. Such an adjustment can prevent the force applied from the conductive member to the power-receiving portion from becoming too large. Effect of the Invention

[0010] According to the present invention, it is possible to provide an electrostatic chuck in which the force applied from the conductive member to the power-receiving portion of the heater unit is not too large. [Brief description of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view illustrating a schematic configuration of an electrostatic chuck according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an exploded view showing a schematic configuration of a heater unit. [Diagram 3] FIG. 2 is an enlarged view of a portion of the configuration of FIG. [Figure 4] 11A and 11B are diagrams for explaining the configuration of an expandable conductive member. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, the present embodiment will be described with reference to the accompanying drawings. In order to facilitate understanding of the description, the same components in each drawing are denoted by the same reference numerals as much as possible, and duplicated description will be omitted.

[0013] The electrostatic chuck 10 according to this embodiment is configured to electrostatically attract and hold a substrate W to be processed inside a semiconductor manufacturing apparatus (not shown), such as an etching apparatus. The substrate W is, for example, a silicon wafer. The electrostatic chuck 10 may be used in an apparatus other than a semiconductor manufacturing apparatus.

[0014] 1 is a schematic cross-sectional view showing the configuration of an electrostatic chuck 10 in a state in which the electrostatic chuck 10 attracts and holds a substrate W. The electrostatic chuck 10 includes a dielectric substrate 100, a base plate 200, and a heater unit 300.

[0015] The dielectric substrate 100 is a substantially disk-shaped member made of a sintered ceramic body. The dielectric substrate 100 contains, for example, high-purity aluminum oxide (Al2O3), but may contain other materials. The purity, type, and additives of the ceramics in the dielectric substrate 100 can be appropriately set in consideration of the plasma resistance and other properties required of the dielectric substrate 100 in semiconductor manufacturing equipment.

[0016] 1 of the dielectric substrate 100 is a "mounting surface" on which the substrate W is mounted. Also, a lower surface 120 of the dielectric substrate 100 in FIG. 1 is a "bonded surface" that is bonded to the heater unit 300 via a bonding layer 410. The viewpoint when the electrostatic chuck 10 is viewed from the side of the surface 110 along a direction perpendicular to the surface 110 will hereinafter be referred to as a "top view".

[0017] An adsorption electrode 130 is embedded inside the dielectric substrate 100. The adsorption electrode 130 is a thin flat layer made of a metal material such as tungsten, and is embedded in the dielectric substrate 100 in a state parallel to the surface 110. The material of the adsorption electrode 130 may be tungsten, molybdenum, platinum, palladium, or the like. When a voltage is applied to the adsorption electrode 130 from the outside via a power supply path (not shown), an electrostatic force is generated between the surface 110 and the substrate W, thereby adsorbing and holding the substrate W. As the configuration of the power supply path, various known configurations can be adopted. The adsorption electrode 130 may be provided as a so-called "monopolar" electrode, as in this embodiment, or may be provided as two so-called "bipolar" electrodes.

[0018] As shown in Fig. 1, a space SP is formed between the dielectric substrate 100 and the substrate W. When a process such as etching is performed in the semiconductor manufacturing apparatus, helium gas for temperature adjustment is supplied from the outside to the space SP through a gas hole (not shown). By providing helium gas between the dielectric substrate 100 and the substrate W, the thermal resistance between them is adjusted, and the temperature of the substrate W is thereby maintained at an appropriate temperature. The temperature adjustment gas supplied to the space SP may be a type of gas other than helium.

[0019] A seal ring 111, dots 112, etc. are provided on a surface 110 serving as a mounting surface, and the above-mentioned space SP is formed around these.

[0020] The seal ring 111 is a wall that divides the space SP at the outermost position. The upper end surface of the seal ring 111 forms part of the surface 110 and abuts against the substrate W. Note that a plurality of seal rings 111 may be provided to divide the space SP. With this configuration, it is possible to individually adjust the pressure of the helium gas in each space SP and make the surface temperature distribution of the substrate W during processing more uniform.

[0021] 1, the portion marked with the reference symbol "116" is the bottom surface of the space SP. Hereinafter, this portion will also be referred to as the "bottom surface 116." The seal ring 111, together with the dots 112 described below, is formed by digging down a part of the surface 110 to the position of the bottom surface 116.

[0022] The dots 112 are circular protrusions protruding from the bottom surface 116. A plurality of dots 112 are provided and are distributed approximately evenly on the mounting surface of the dielectric substrate 100. The upper end of each dot 112 forms part of the surface 110 and abuts against the substrate W. By providing a plurality of such dots 112, bending of the substrate W is suppressed.

[0023] The base plate 200 is a substantially disk-shaped member that supports the dielectric substrate 100 and the heater unit 300. The base plate 200 is formed of a metal material such as aluminum. The upper surface 210 of the base plate 200 in FIG. 1 is a "bonded surface" that is bonded to the heater unit 300 via a bonding layer 420.

[0024] A coolant flow path 250 for flowing a coolant is formed inside the base plate 200. When a process such as etching is performed in the semiconductor manufacturing apparatus, a coolant is supplied to the coolant flow path 250 from the outside, thereby cooling the base plate 200. Heat generated in the substrate W during the process is transferred to the coolant via 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 coolant.

[0025] An insulating film may be formed on the surface of the base plate 200. For example, an alumina film formed by thermal spraying can be used as the insulating film. By covering the surface of the base plate 200 with the insulating film, the dielectric strength of the base plate 200 can be increased.

[0026] The heater unit 300 generates heat when power is supplied from an external source, and heats the dielectric substrate 100. The heater unit 300 is provided with a plurality of heat generating parts (not shown), and the amount of heat generated by each heat generating part can be adjusted individually. By individually adjusting the amount of heat generated by each part, the in-plane temperature distribution of the substrate W during processing can be made closer to uniform.

[0027] The heater unit 300 is sandwiched between the dielectric substrate 100 and the base plate 200 and bonded to each of them. The heater unit 300 and the dielectric substrate 100 are bonded via a bonding layer 410, and the heater unit 300 and the base plate 200 are bonded via a bonding layer 420. The bonding layers 410 and 420 are layers formed by, for example, hardening a silicone adhesive. A plurality of particulate fillers (fillers) for increasing thermal conductivity are disposed inside each of the bonding layers. For example, particles mainly composed of alumina can be used as the filler.

[0028] 2 shows a schematic exploded view of the configuration of the heater unit 300. As shown in the figure, the heater unit 300 has a support plate 310 (310A), an insulating layer 320, a sub-heater layer 330, an insulating layer 340, a main heater layer 350, an insulating layer 360, a bypass layer 370, an insulating layer 380, a support plate 310 (310B), and a conductive member 500. In this embodiment, the sub-heater layer 330, the main heater layer 350, and the bypass layer 370 are arranged in this order from the top, but the arrangement order of these may be different from that of this embodiment.

[0029] The support plate 310 is a substantially disk-shaped member, and is provided at each of the upper and lower ends of the heater unit 300 in FIG. 2. The support plate 310 provided at the upper end in FIG. 2 is also referred to as "support plate 310A" below. The support plate 310 provided at the lower end in FIG. 2 is also referred to as "support plate 310B" below. The support plate 310A is a portion bonded to the dielectric substrate 100 via a bonding layer 410, and the support plate 310B is a portion bonded to the base plate 200 via a bonding layer 420.

[0030] The pair of support plates 310A, 310B are members for reinforcing the entire heater unit 300 by sandwiching the entire sub-heater layer 330, the main heater layer 350, the bypass layer 370, etc. between them. In this embodiment, both the support plates 310A, 310B are made of metal, but they may be made of other materials (e.g., insulating materials). Note that, although a plurality of through holes are formed in each of the members constituting the heater unit 300, such as the support plate 310, for the purpose of passing lift pins through, etc., they are not shown in FIG. 2.

[0031] The insulating layer 320 is provided between the support plate 310A and the sub-heater layer 330, and serves to electrically insulate them from each other. The insulating layer 320 also serves to physically bond them together. In this embodiment, the insulating layer 320 is a polyimide film, but it may contain a component other than polyimide, or may be made of a material other than polyimide. When the support plate 310A is made of an insulating material, it is possible to eliminate the insulating layer 320.

[0032] The sub-heater layer 330 is a part that generates heat when power is supplied from the outside. In Fig. 2, the sub-heater layer 330 is depicted as a single disk, but in reality, the sub-heater layer 330 is divided into a plurality of regions, and each region is formed as a heating portion that is wired. This makes it possible to heat each region individually.

[0033] The insulating layer 340 is provided between the sub-heater layer 330 and the main heater layer 350, and serves to electrically insulate the two layers from each other. The insulating layer 340 also serves to physically bond the two layers together. In this embodiment, the insulating layer 340 is a polyimide film, but it may contain a component other than polyimide, or may be made of a material other than polyimide.

[0034] The main heater layer 350, like the sub-heater layer 330 described above, is a part that receives power from an external source and generates heat. In Fig. 2, the main heater layer 350 is depicted as a single disk, but in reality, the main heater layer 350 is divided into a plurality of regions, and each region is formed as a linearly routed heat generating portion. This makes it possible to heat each region individually. The number of divisions of the main heater layer 350 is smaller than that of the sub-heater layer 330.

[0035] The main heater layer 350 has a larger heat generation amount than the sub-heater layer 330 described above. The main heater layer 350 is intended to increase the temperature of the entire dielectric substrate 100 in a short period of time. The sub-heater layer 330 is intended to adjust the temperature of each part of the dielectric substrate 100 and make the in-plane temperature distribution of the substrate W closer to uniform. In this manner, in this embodiment, two heater layers are provided separately according to their respective roles. Alternatively, a configuration in which only one heater layer is provided may be used.

[0036] The insulating layer 360 is provided between the main heater layer 350 and the bypass layer 370, and serves to electrically insulate the two layers from each other. The insulating layer 360 also serves to physically bond the two layers together. In this embodiment, the insulating layer 360 is a polyimide film, but it may contain a component other than polyimide, or may be made of a material other than polyimide.

[0037] The bypass layer 370 is a layer for electrically connecting the conductive member 500 described below to the sub-heater layer 330 and the main heater layer 350. In FIG. 2, the bypass layer 370 is illustrated as a single disk, but in reality, the bypass layer 370 is divided into a plurality of layers. By providing the bypass layer 370 in the middle of each electric path connecting the conductive member 500 to the sub-heater layer 330 or the main heater layer 350, it becomes possible to adjust the position of the conductive member 500, etc. Each divided bypass layer 370 has a part welded to the sub-heater layer 330 or the main heater layer 350.

[0038] In addition, there may be an embodiment in which the conductive member 500 and the sub-heater layer 330, and the conductive member 500 and the main heater layer 350 are directly connected to each other. In this case, the bypass layer 370 is not necessary.

[0039] The insulating layer 380 is provided between the bypass layer 370 and the support plate 310B, and serves to electrically insulate the two. The insulating layer 380 also serves to physically bond the two. In this embodiment, the insulating layer 380 is a polyimide film, but it may contain a component other than polyimide, or may be made of a material other than polyimide. If the support plate 310B is made of an insulating material, it is possible to eliminate the insulating layer 380.

[0040] 2 are laminated, the entire assembly is pressurized and heated, and the entire assembly is bonded together via the insulating layer 320, which is a polyimide film, and the like.

[0041] The conductive member 500 is a member provided as a part of an electric path for supplying power for heating to the heater unit 300. The conductive member 500 is provided as a so-called contact probe, and one end of the conductive member 500 abuts against one of the bypass layers 370 through an opening (not shown) formed in the insulating layer 380 and the support plate 310B. A plurality of conductive members 500 are provided according to the number of bypass layers 370, but only two of them are shown in FIG. 2 and only one of them is shown in FIG. 1. When the bypass layer 370 is not provided on the base plate 200, one end of the conductive member 500 is in a state of abutting against either the sub-heater layer 330 or the main heater layer 350.

[0042] In the base plate 200, through holes 230 are formed at positions corresponding to the conductive members 500. Each conductive member 500 is housed and held inside the through hole 230. The through hole 230 is a through hole formed so as to penetrate the base plate 200 from the surface 210 of the base plate 200 to the surface 220 on the opposite side. The central axis of the through hole 230 is perpendicular to the surface 210.

[0043] The specific configuration of the conductive member 500 and its vicinity will be described with reference to FIG. 3. FIG. 3 is an enlarged view of the conductive member 500 and its vicinity in FIG. 1. In FIG. 3, the tip 511, which is the upper end of the conductive member 500, is depicted as being in contact with the lower end surface of the heater unit 300 (i.e., the support plate 310B in FIG. 2). However, the actual tip 511 is in contact with the bypass layer 370 inside the heater unit 300 through an opening (not shown) formed in the support plate 310B or the like. The portion of the bypass layer 370 that the tip 511 is in contact with corresponds to a "power-supplied portion" that receives power from the outside. Hereinafter, this portion is also referred to as a "power-supplied portion 371."

[0044] The conductive member 500 has a first conductive member 510 and a second conductive member 520, and is configured as a contact probe that is expandable as a whole. The first conductive member 510 and the second conductive member 520 are both made of metal and have electrical conductivity.

[0045] First conductive member 510 is a substantially cylindrical member. An end portion of first conductive member 510 on the upper side in FIG.

[0046] The second conductive member 520 is a member having a substantially cylindrical shape similar to the first conductive member 510, but its outer diameter is larger than that of the first conductive member 510. The second conductive member 520 has a recess 521 extending downward from the upper end of FIG. 3. The recess 521 has a circular shape in top view, and its inner diameter is approximately equal to the outer diameter of the first conductive member 510. The central axis of the first conductive member 510 and the central axis of the recess 521 are both coincident with the central axis of the through hole 230. As shown in FIG. 3, a part of the first conductive member 510 is inserted into the recess 521 from above, and is supported from the periphery by the second conductive member 520. The first conductive member 510 can move in the vertical direction of FIG. 3 along the central axis of the recess 521. That is, the first conductive member 510 is movable relative to the second conductive member 520, and the entire conductive member 500 is expandable and contractible.

[0047] An elastic member (not shown) is disposed in recess 521. In the state shown in Fig. 3, the elastic member is compressed. Therefore, first conductive member 510 is urged upward by the restoring force of the elastic member, and tip portion 511 is pressed against power-supplied portion 371.

[0048] 4(A) illustrates the conductive member 500 in a "natural length" state with no external force being applied. The dotted line in the figure indicates the position of the power-supplied portion 371 with which the tip portion 511 abuts. When an upward force is applied to the second conductive member 520 from the state of FIG. 4(A), the position of the first conductive member 510 does not change, and only the second conductive member 520 moves upward to the state of FIG. 4(B). As the second conductive member 520 moves upward, the compression amount of the elastic member (not shown) increases, and the force with which the tip portion 511 is pressed against the power-supplied portion 371 also increases.

[0049] 3, conductive member 500 is held in a compressed state by holding member 600, which will be described later. Therefore, tip portion 511 is pressed against power-supplied portion 371 by the restoring force of conductive member 500. In this manner, tip portion 511 of conductive member 500 abuts against power-supplied portion 371 by the restoring force from the compressed state.

[0050] In second conductive member 520, a portion on the inner side (lower side in FIG. 3) of the bottom surface of recess 521 has a larger diameter than the other portions. Hereinafter, this portion is also referred to as "larger diameter portion 522."

[0051] In the second conductive member 520, a portion marked with the reference symbol "523" in FIG. 3 is a generally cylindrical portion extending from the expanded diameter portion 522 toward the opposite side to the tip portion 511. This portion is also referred to as the "cylindrical portion 523" below. The end portion of the cylindrical portion 523 on the lower side in FIG. 3 is the end portion of the conductive member 500 opposite to the tip portion 511. This end portion is also referred to as the "rear end portion 524" below. The central axis of the expanded diameter portion 522 and the central axis of the cylindrical portion 523 both coincide with the central axis of the portion of the second conductive member 520 where the recess 521 is formed.

[0052] In addition to the conductive member 500, a holding member 600 is also disposed inside the through hole 230. The holding member 600 is a member for holding the conductive member 500 in a compressed state. The holding member 600 has a first holding member 610 and a second holding member 620.

[0053] The first holding member 610 is a substantially cylindrical member formed to cover the inner surface of the through hole 230. The first holding member 610 is formed of an insulating material such as resin. The central axis of the first holding member 610 coincides with the central axis of the through hole 230. The outer surface of the first holding member 610 is fitted or joined to the inner surface of the through hole 230. The first holding member 610 has a first portion 611, a second portion 612, and a third portion 613.

[0054] The first portion 611 is a cylindrical portion formed to extend linearly downward from the upper end of the holding member 600 in Fig. 3. The upper end of the first portion 611 protrudes outward from the surface 210 and abuts against the heater unit 300. The inner diameter of the first portion 611 is approximately equal to the outer diameter of the portion of the first conductive member 510 where the recess 521 is formed. The first portion 611 covers the above-mentioned portion of the first conductive member 510 from the outside.

[0055] The second portion 612 is a portion formed so as to extend outward from the lower end of the first portion 611 in Fig. 3. The third portion 613 is a substantially cylindrical portion formed so as to extend from the outer peripheral end of the second portion 612 downward in Fig. 3. In order to dispose such a third portion 613, the portion of the through hole 230 on the surface 220 side is enlarged in diameter compared to the other portions. The portion of the through hole 230 that is enlarged in diameter in this manner is hereinafter also referred to as "enlarged diameter portion 231".

[0056] The outer diameter of third portion 613 is slightly smaller than the inner diameter of expanded diameter portion 231. The inner diameter of third portion 613 is approximately equal to the outer diameter of expanded diameter portion 522 of second conductive member 520. Third portion 613 covers expanded diameter portion 522 from the outside. The length of third portion 613 in the vertical direction of FIG. 3 is longer than the length (i.e., thickness) of expanded diameter portion 522 in the same direction.

[0057] The second holding member 620 is a substantially cylindrical member disposed closer to the surface 220 than the first holding member 610. The second holding member 620 is formed of an insulating material such as resin. The second holding member 620 has a through hole 624 formed therethrough along its central axis. The inner diameter of the through hole 624 is slightly larger than the inner diameter of the cylindrical portion 523 of the second conductive member 520. The cylindrical portion 523 is inserted through the through hole 624. The rear end portion 524 of the second conductive member 520 is exposed to the surface 220 through the through hole 624.

[0058] The second holding member 620 has a first portion 621 and a second portion 622. The first portion 621 is a portion of the second holding member 620 on the upper side in FIG. 3, and the second portion 622 is a portion on the opposite side. The central axis of the first portion 621 and the central axis of the second portion 622 both coincide with the central axis of the through hole 230.

[0059] The outer diameter of the first portion 621 is slightly smaller than the inner diameter of the third portion 613 of the first holding member 610. The first portion 621 enters inside the third portion 613 from the lower side in FIG.

[0060] The outer diameter of the second portion 622 is larger than the outer diameter of the third portion 613 of the first holding member 610. A male screw 623 is formed on the outer surface of the second portion 622. A female screw 233 is formed on the inner peripheral surface of the enlarged diameter portion 231 of the through hole 230, and is screwed with the male screw 623. When the second holding member 620 is rotated around its central axis, the second holding member 620 moves along its central axis. At this time, the second conductive member 520 including the rear end portion 524 also moves in the same direction together with the second holding member 620, so that the compression state of the conductive member 500 changes, and the force pressing the tip portion 511 against the bypass layer 370 also changes.

[0061] In this way, the holding member 600 according to this embodiment holds the conductive member 500 in a state where the rear end 524 opposite to the tip 511 of the conductive member 500 is exposed to the outside, and is configured to be able to adjust the position of the rear end 524. Such position adjustment of the tip 511, i.e., adjustment of the compressed state of the conductive member 500, is realized by the second holding member 620, the male screw 623 formed thereon, the female screw 233 screwed with the male screw 623, and the like. The mechanism formed by the second holding member 620 and the like corresponds to the "adjustment mechanism" in this embodiment. The rear end 524 shown in FIG. 3 is in a state where it has moved to the uppermost end of its movable range.

[0062] It is also possible to always keep the dimensions of the conductive member 500 attached to the electrostatic chuck 10, i.e., the dimensions in the compressed state, constant (i.e., unadjustable) without providing such an adjustment mechanism. However, in such a configuration, an excessive force may be applied from the tip portion 511 to the power supply portion 371 due to individual variations in the conductive member 500, which may cause deformation of the heater unit 300.

[0063] Therefore, in this embodiment, the adjustment mechanism as described above is provided. By making the position of rear end portion 524 adjustable, it is possible to prevent the force applied from conductive member 500 to power-supplied portion 371 from becoming too large.

[0064] As described above, the adjustment mechanism includes the male screw 623 formed on the outer surface of the second holding member 620, and the female screw 233 that screws into the male screw 623. With this configuration, the position of the rear end portion 524 can be easily adjusted by simply rotating the second holding member 620 around its central axis.

[0065] If the adjustment mechanism moves the rear end 524 too far toward the tip end 511, the force pressing the tip end 511 against the bypass layer 370 becomes too large. However, in this embodiment, before such a state is reached, the second portion 612 of the first holding member 610 abuts against the enlarged diameter portion 522 of the second conductive member 520, and the second conductive member 520 cannot be moved further toward the tip end 511. This prevents a strong force from being applied to the bypass layer 370. The second portion 612 corresponds to an "approach prevention mechanism" that prevents the rear end 524 from approaching too close to the tip end 511.

[0066] The approach prevention mechanism of this embodiment is configured to restrict movement of the rear end 524 by contacting the second conductive member 520 from the power-receiving portion 371 side (i.e., from the upper side of FIG. 3). Instead of this embodiment, the approach prevention mechanism may be configured to restrict movement of the rear end 524 by contacting the second holding member 620 from the power-receiving portion 371 side. For example, the above-mentioned configuration can be realized by extending the tip of the third portion 613 long toward the lower side of FIG. 3 so that the tip of the third portion 613 contacts the second portion 622 of the second holding member 620 before the second portion 612 contacts the enlarged diameter portion 522. In this case, the third portion 613 corresponds to the "approach prevention mechanism".

[0067] The access prevention mechanism may be a part of the first holding member 610 as in the above example, but may also be a part of a member different from the first holding member 610 (for example, the base plate 200).

[0068] Power may be supplied to the heater unit 300 at all locations via conductive members 500 which are contact probes, but may also be supplied at some locations via rod-shaped terminals whose tips are welded to the bypass layer 370.

[0069] The heater unit 300 may be provided separately from the dielectric substrate 100 as in this embodiment, or may be integrated with the dielectric substrate 100. For example, a linear heat generating portion may be embedded inside the dielectric substrate 100, and the tip portion 511 of the conductive member 500 may be pressed against the heat generating portion. In this case, the dielectric substrate 100 corresponds to the "heater unit" and is joined to a base plate 200 having the same configuration as this embodiment.

[0070] The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Any design modifications made by a person skilled in the art to these specific examples are also included within the scope of the present disclosure as long as they have the features of the present disclosure. The elements of each of the above-mentioned specific examples and their arrangements, conditions, shapes, etc. are not limited to those exemplified and can be changed as appropriate. The combination of each of the elements of each of the above-mentioned specific examples can be changed as appropriate as long as no technical contradiction occurs. [Explanation of symbols]

[0071] 10: Electrostatic chuck 200: Base plate 233: Female screw 300: Heater unit 371: Powered part 500: Conductive materials 511:Tip 524: Rear end 600: Retaining member 610: First holding member 612:Second part 613: 3rd part 620: Second holding member 623: Male screw

Claims

1. A heater unit having a power-receiving part that receives power from an external source; a conductive member having a tip end that is in contact with the power-receiving portion by a restoring force from a compressed state; a holding member that holds the conductive member in a compressed state, The holding member is the conductive member is held in a state where a rear end portion of the conductive member opposite to the front end portion is exposed to the outside, The electrostatic chuck further comprises an adjustment mechanism for adjusting the position of the rear end portion.

2. 2. The electrostatic chuck according to claim 1, wherein the adjustment mechanism includes a male screw formed on an outer surface of the holding member, and a female screw that screws into the male screw.

3. 2. The electrostatic chuck according to claim 1, further comprising an approach prevention mechanism that prevents the rear end from approaching too close to the front end.

4. The access prevention mechanism includes:

4. The electrostatic chuck according to claim 3, wherein the electrostatic chuck is configured to restrict movement of the rear end portion by contacting the holding member or the conductive member from the power supply portion side.

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