Electrostatic chuck

Abstract

To provide an electrostatic chuck capable of suppressing a local temperature rise of a heater.SOLUTION: An electrostatic chuck 10 includes a dielectric substrate 100, and a heater unit 300 that heats the dielectric substrate 100. The heater unit 300 includes: a power supply portion 390 that receives power from an external source; a heat generating portion 331 that is a linear conductor and generates heat upon receiving power from the power supply portion 390; and a bypass layer 370 that connects the power supply portion 390 and the heat generating portion 331. The heat generating portion 331 includes a width-expanded portion 332 that is a portion where the line width of the heat generating portion is locally expanded. The bypass layer 370 is connected to the heat generating portion 331 at a plurality of points of the width-expanded portion 332.SELECTED DRAWING: Figure 9

Description

[Technical field]

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

[0002] For example, in semiconductor manufacturing equipment such as an etching device, 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 has a dielectric substrate on which an attracting electrode is provided. 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.

[0003] When a substrate is processed in a semiconductor manufacturing device, it is necessary to adjust the temperature so that the temperature distribution within the surface of the substrate is as uniform as possible. In order to enable high-precision temperature adjustment, 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 as a unit between the dielectric substrate and the base plate, as described in Patent Document 1 below. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-197485 Summary of the Invention [Problem to be solved by the invention]

[0005] The heater has a power supply part, such as a power supply terminal, and a heat generating part, which is a conductor drawn in a linear shape. When power is supplied to the power supply part from the outside and a current flows through the heat generating part, Joule heat is generated in the heat generating part.

[0006] It is preferable that the power supply unit and the heat generating unit are connected via a bypass unit rather than directly. By providing the bypass unit, it is possible to increase the degree of freedom in arranging the power supply unit in the heater.

[0007] In this case, a part of the bypass is connected to the heat generating part, for example, by welding. The part of the heat generating part to which the bypass is connected is hereinafter also referred to as the "connection part". When the heater generates heat, current passes through the relatively narrow connection part, so there is a possibility that a local temperature rise occurs at the connection part. As a result, there is a concern that the temperature distribution within the surface of the substrate during processing will become uneven, which may have a negative impact on the processing.

[0008] The present invention has been made in view of the above problems, and has an object to provide an electrostatic chuck capable of suppressing a local temperature rise of a heater. [Means for solving the problem]

[0009] In order to solve the above problems, an electrostatic chuck according to the present invention includes a dielectric substrate and a heater for heating the dielectric substrate. The heater includes a power supply part that receives power from an external source, a heat generating part that is a linear conductor and generates heat upon receiving power from the power supply part, and a bypass part that connects the power supply part and the heat generating part. The heat generating part has an expanded part that is a part whose line width is locally expanded. The bypass part is connected to the heat generating part at a plurality of points of the expanded part.

[0010] In an electrostatic chuck having such a configuration, a current supplied to the heat generating portion flows through a path that passes through a portion of the widened portion to which the bypass portion is connected. This portion is hereinafter also referred to as a "connection portion."

[0011] The bypass section is connected to the heat generating section at multiple points in the widening section. That is, multiple connection sections are present in one widening section. In this configuration, the current supplied from the bypass section to the heat generating section does not flow concentratedly at a single connection section, but flows dispersedly at multiple connection sections. Since the Joule heat generated at each connection section is small, local temperature rise at the connection sections can be suppressed. Effect of the Invention

[0012] According to the present invention, it is possible to provide an electrostatic chuck capable of suppressing a local temperature rise of a heater. [Brief description of the drawings]

[0013] [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] 5A to 5C are diagrams illustrating examples of arrangement of sub-heater layers in a heater unit. [Figure 4] FIG. 1 is a diagram showing the configuration of one sub-heater layer. [Diagram 5] 5A to 5C are diagrams showing examples of the arrangement of main heater layers in a heater unit. [Figure 6] FIG. 1 is a diagram showing the configuration of one main heater layer. [Figure 7] FIG. 13 is a diagram for explaining the role of a bypass layer, etc. [Figure 8] FIG. 3 is a cross-sectional view showing a configuration of a welded portion and its surroundings in the heater unit. [Figure 9] 13A and 13B are diagrams illustrating examples of arrangements of connection parts in a widening section. [Figure 10] 13A and 13B are diagrams illustrating examples of arrangements of connection parts in a widening section. [Figure 11] 13A and 13B are diagrams illustrating examples of arrangements of connection parts in a widening section. [Figure 12]13A and 13B are diagrams illustrating examples of arrangements of connection parts in a widening section. [Figure 13] 13A and 13B are diagrams illustrating examples of arrangements of connection parts in a widening section. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] 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.

[0015] 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 to be attracted is, for example, a silicon wafer. The electrostatic chuck 10 may be used in an apparatus other than a semiconductor manufacturing apparatus.

[0016] 1 shows, in a schematic cross-sectional view, 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.

[0017] The dielectric substrate 100 is a substantially disk-shaped member made of a sintered ceramic body. The dielectric substrate 100 is made of, for example, high-purity aluminum oxide (Al 2 O 3 ), 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, etc. required for the dielectric substrate 100 in the semiconductor manufacturing equipment.

[0018] 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".

[0019] 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 arranged parallel to the surface 110. The material of the adsorption electrode 130 may be molybdenum, platinum, palladium, or the like, in addition to tungsten. 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.

[0020] 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.

[0021] A seal ring 111 and dots 112 are provided on a surface 110 serving as a mounting surface, and the above-mentioned space SP is formed around these.

[0022] The seal ring 111 is a wall that divides the space SP at the outermost position. The upper end 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] The heater unit 300 generates heat when power is supplied from an external source, and heats the dielectric substrate 100. As will be described later, the heater unit 300 is provided with a plurality of heat generating parts 331, etc., and the amount of heat generated by each of the heat generating parts 331, etc. can be individually adjusted. 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.

[0029] 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.

[0030] A specific configuration of the heater unit 300 will be described. In FIG. 2, the configuration of the heater unit 300 is shown as a schematic exploded view. 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 power supply section 390. 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.

[0031] 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.

[0032] 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). As will be described later, openings 311 are formed in the support plates 310A, 310B, but are not shown in FIG. 2.

[0033] 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.

[0034] 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 can be individually heated. The specific configuration of the sub-heater layer 330 will be described later.

[0035] 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.

[0036] 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 can be individually heated. The specific configuration of the main heater layer 350 will be described later.

[0037] 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.

[0038] 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.

[0039] The bypass layer 370 is a layer for electrically connecting the power supply unit 390, which will be described later, 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 the electric path connected to the sub-heater layer 330, etc., it becomes possible to adjust the position of the power supply unit 390, etc. Each of the divided bypass layers 370 has a part welded to the sub-heater layer 330 or the main heater layer 350. Each of the divided bypass layers 370 corresponds to the "bypass section" in this embodiment.

[0040] 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.

[0041] 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.

[0042] The power supply unit 390 is a part that receives, from the outside, the power required to heat the sub-heater layer 330 and the like. In this embodiment, the power supply unit 390 is formed as a long, thin rod-shaped plug, one end of which is connected to the bypass layer 370. A plurality of power supply units 390 are provided according to the number of bypass layers 370, but only two of them are shown in FIG. 2. Through holes (not shown) are formed in the base plate 200 at positions corresponding to the power supply units 390, and the power supply units 390 are inserted through the through holes.

[0043] The structure of the sub-heater layer 330 will now be described. As described above, the sub-heater layer 330 is divided into a plurality of regions, and each region can be individually heated. Fig. 3 shows an example of how the sub-heater layer 330 is divided from a top view. In this example, the sub-heater layer 330 is divided into a total of 24 regions HA.

[0044] Each of the divided sub-heater layers 330 is configured as a linear heat generating portion 331, which is routed individually in each region HA. The heat generating portion 331 is a linear conductor, which generates heat when supplied with power from a power supply portion 390. Fig. 4 shows an example of the heat generating portion 331 routed in one region HA. In each region HA, one linear heat generating portion 331 is routed along a path that passes evenly through almost the entire range. Two or more heat generating portions 331 connected in parallel to each other may be routed.

[0045] Circular widened portions 332, 333 are formed at both ends of the heat generating portion 331. The widened portions 332, 333 are both parts of the heat generating portion 331, and are portions in which the line width is locally expanded. The widened portions 332, 333 are portions to which the bypass layer 370 is electrically connected via a welded portion 301, which will be described later. The widened portions 332, 333 may have a circular shape as in this embodiment, or may have a shape other than a circular shape.

[0046] The heat generating portion 331 including the widened portions 332, 333 is formed, for example, by etching a thin metal foil, and the entire portion functions as one sub-heater layer 330. In other words, one sub-heater layer 330 is provided for each of the 24 regions HA in total.

[0047] 4 is a schematic view and differs from the actual shape. For example, there may be a sub-heater layer 330 in which the widened portion 332 is provided not at the end of the heat generating portion 331 but at a position midway along the heat generating portion 331.

[0048] The structure of the main heater layer 350 will now be described. Like the sub-heater layer 330, the main heater layer 350 is also divided into multiple regions, and each region can generate heat individually. Figure 5 shows an example of how the main heater layer 350 is divided from a top view. In this example, the main heater layer 350 is divided into a total of three regions HB.

[0049] Each of the divided main heater layers 350 is configured as a linear heat generating portion 351, which is individually routed in each region HB. Like the heat generating portion 331, the heat generating portion 351 is a conductor routed in a linear shape, and generates heat when power is supplied from the power supply portion 390. Fig. 6 shows an example of the heat generating portion 351 routed in one region HB. In each region HB, one linear heat generating portion 351 is routed along a path that passes evenly through almost the entire range. Two or more heat generating portions 351 connected in parallel to each other may be routed.

[0050] Circular widened portions 352, 353 are formed on both ends of the heat generating portion 351. The widened portions 352, 353 are both parts of the heat generating portion 351, and are portions in which the line width is locally expanded. The widened portions 352, 353 are portions to which the bypass layer 370 is electrically connected via the welded portion 301. The shape of the widened portions 352, 353 may be circular as in this embodiment, or may be a shape other than circular.

[0051] The heat generating portion 351 including the widened portions 352 and 353 is formed, for example, by etching a thin metal foil, and the entire portion functions as one main heater layer 350. In other words, one main heater layer 350 is provided for each of the three regions HB.

[0052] 6 is a schematic view and differs from the actual shape of the main heater layer 350. For example, there may be a main heater layer 350 in which the widened portion 352 and the like are provided not at the end of the heat generating portion 351 but at a position midway along the heat generating portion 351.

[0053] 7 shows, as a schematic perspective view, two regions HA, two sub-heater layers 330 arranged therein, and a bypass layer 370 connected to the sub-heater layers 330. One of the two regions HA shown in FIG. 7 is also referred to as "region HA1" below. The other region HA is also referred to as "region HA2" below. Note that the shapes of the heat generating portion 331 and the like shown in FIG. 7 are schematic and differ from the actual shapes.

[0054] As described above, the bypass layer 370 is divided into a plurality of parts. In FIG. 7, only three of the plurality of divided bypass layers 370 are shown. Of the three divided bypass layers 370, the one marked with the reference symbol "371" in FIG. 7 is disposed at a position overlapping only one region HA in top view. In other words, each of the bypass layers 370 is disposed at a position directly below each of the regions HA. The portion of the bypass layer 370 disposed in this manner is hereinafter also referred to as the "bypass layer 371."

[0055] 7 is disposed at a position overlapping both the region HA1 and the region HA2 in top view. The portion of the bypass layer 370 disposed in this manner is hereinafter also referred to as the "bypass layer 372."

[0056] In the sub-heater layer 330 arranged in the region HA1, the widened portion 332 at one end of the heat generating portion 331 is electrically connected to the bypass layer 371 located immediately below it. The widened portion 333 at the other end of the heat generating portion 331 is electrically connected to the bypass layer 372.

[0057] The sub-heater layer 330 arranged in the region HA2 is similar to the above, and the widened portion 332 at one end of the heat generating portion 331 is electrically connected to the bypass layer 371 located immediately below it. The widened portion 333 at the other end of the heat generating portion 331 is electrically connected to the bypass layer 372.

[0058] In this embodiment, the electrical connection of each part as described above is realized by welding the upper and lower layers together. In order to make the configuration easier to understand, in Fig. 7, each welded part is depicted as a rod-shaped member (parts marked with reference numeral 301) extending linearly, but the actual shape of the welded part is different from this. In addition, in the parts overlapping with each welded part in top view, openings are formed in each layer (insulating layer 340, main heater layer 350, and insulating layer 360) between the sub-heater layer 330 and the bypass layer 370, and the sub-heater layer 330 and the bypass layer 370 directly overlap through the openings.

[0059] One end of a power supply unit 390 is connected to each of the bypass layers 371 from below in Fig. 7. A voltage is individually applied to each of the power supply units 390 from an external DC power supply. Similarly, one end of a power supply unit 390 is connected to the bypass layer 372 from below in Fig. 7. This power supply unit 390 is grounded.

[0060] As described above, in each of the sub-heater layers 330 (heat generating portions 331) provided for each region HA, the widened portions 332 are connected to individual DC power supplies via the bypass layer 371, and the widened portions 333 are grounded via the common bypass layer 372. The other sub-heater layers 330 not shown in Fig. 7 are also connected to DC power supplies or the like in a similar configuration. With this configuration, it is possible to individually supply power to each of the multiple sub-heater layers 330 provided, and adjust the amount of heat generated in each portion.

[0061] It is also possible to supply power to the sub-heater layer 330 directly from the power supply unit 390 without passing through the bypass layer 370. However, by using a configuration in which power is supplied through the bypass layer 370 as in this embodiment, it is possible to increase the degree of freedom in arranging the power supply units 390 and to consolidate the power supply units 390 that are grounded into one.

[0062] The supply of power to each main heater layer 350 is achieved by the same configuration as above. The specific configuration is the same as that shown in Fig. 7, so description and illustration thereof will be omitted. The bypass layer 370 connected to the sub-heater layer 330 and the bypass layer 370 connected to the main heater layer 350 may be disposed at the same height position (the position of the bypass layer 370 shown in Fig. 2) as in this embodiment, but may also be disposed at different height positions.

[0063] As described above, in the heater unit 300, the sub-heater layer 330 and the bypass layer 370 are welded and electrically connected to each other. Such a welded portion is hereinafter also referred to as a "welded portion 301."

[0064] Fig. 8 is a cross-sectional view showing the configuration of the welded portion 301 and its vicinity in the heater unit 300. As shown in Fig. 8, in a part of the heater unit 300, the sub-heater layer 330 and the bypass layer 370 are overlapped with each other and connected together by, for example, resistance spot welding, without the insulating layers 340, 360 and the main heater layer 350 therebetween. The portion of the heat generating portion 331 that is connected to the bypass layer 370 by the welded portion 301 is the portion that is inside the widened portions 332, 333.

[0065] In this embodiment, two welds 301 are formed in positions close to each other as shown in Fig. 8. That is, two welds 301 shown in Fig. 7 are actually formed in each of the widened portions 332 (or widened portions 333). Note that the number of welds 301 arranged close to each other inside one widened portion 332 may be three or more. The number and intervals of welds 301 may be appropriately set depending on the welding method to be adopted, etc.

[0066] After the sub-heater layer 330 and the bypass layer 370 are welded as described above, the sub-heater layer 330 and the like are sandwiched between a pair of support plates 310. The welded portion 301 is raised as described above, and protrudes toward the upper side of the insulating layer 320 and the lower side of the insulating layer 380 in Fig. 8. Therefore, depending on the size of the welded portion 301, when the entire sub-heater layer 330 and the like are sandwiched between the pair of support plates 310, the welded portion 301 may come into contact with the support plates 310, and the outer surface of the support plates 310 may be deformed to become locally convex.

[0067] Therefore, in the electrostatic chuck 10 according to this embodiment, an opening 311 is formed in the support plate 310 at a position facing the welded portion 301. The opening 311 is a circular opening, and two welded portions 301 are housed inside one opening 311 in a top view. Since the welded portion 301 does not come into contact with the support plate 310, even if the welded portion 301 is locally raised, the support plate 310 will not be deformed.

[0068] The opening 311 may be formed in both of the pair of support plates 310A, 310B, or may be formed in only one of them. However, forming the opening 311 in both of the support plates 310A, 310B as in this embodiment is more preferable because it can prevent deformation of the support plate 310 on both sides of the heater unit 300.

[0069] 9 shows a top view of the configuration of the heat generating portion 331 near the widened portion 332 at its end. As described above, the widened portion 332 is connected to the bypass layer 370 via each of the two welded portions 301. The portion of the widened portion 332 where the welded portion 301 is provided, i.e., the portion of the widened portion 332 to which the bypass layer 370 is connected, is hereinafter also referred to as the "connection portion 301A."

[0070] In this embodiment, two or more connection parts 301A are provided in each of all the widened parts 332 etc. of the heat generating part 331. In other words, the bypass layer 370 is connected to the heat generating part 331 at multiple points on the inside of each of the widened parts 332 etc.

[0071] If only one connection part 301A is provided inside the widened part 332, when the heater unit 300 generates heat, a current passes through the relatively narrow and single connection part 301A, which may cause a local temperature rise at the connection part 301A. As a result, there is a concern that the in-plane temperature distribution of the substrate W during processing may become non-uniform, which may adversely affect the processing.

[0072] Therefore, in this embodiment, as described above, the bypass layer 370 is connected to the heat generating portion 331 at a plurality of points in the widened portion 332. In such a configuration, the current supplied from the bypass layer 370 to the widened portion 332 of the heat generating portion 331 does not flow intensively to a single connection portion 301A, but flows dispersedly to the plurality of connection portions 301A. Since the Joule heat generated in each connection portion 301A is reduced, it is possible to suppress a local temperature rise in the connection portion 301A.

[0073] In Fig. 9, the dotted line marked with the symbol "BD" indicates the boundary between the widened portion 332 and the other portions of the heat generating portion 331. Such a boundary is also referred to as "boundary BD" below. Also, the dotted line DL shown in Fig. 9 is a line that passes through the centers of the two connecting portions 301A inside the widened portion 332. The dotted line DL indicates the direction in which the two connecting portions 301A are arranged.

[0074] 9 indicates the direction from the center CT of the widened portion 332 toward the boundary portion BD. Specifically, the "direction toward the boundary portion BD" refers to the direction toward the center in the width direction of the boundary portion BD. Note that, when the shape of the widened portion 332 in top view is other than circular, the "center CT of the widened portion 332" refers to the center of gravity of the widened portion 332.

[0075] In this embodiment, the dotted line DL extends along a direction perpendicular to the direction indicated by the arrow AR1 in Fig. 9. That is, a pair of connection parts 301A in the widened part 332 are arranged to be aligned along a direction perpendicular to the direction from the center CT of the widened part 332 toward the boundary part BD (i.e., the direction of the dotted line DL).

[0076] In such a configuration, the magnitude of the current flowing from each connection portion 301A to the boundary portion BD can be made approximately equal. Since the current does not flow unevenly in one of the connection portions 301A, the local temperature rise in the connection portion 301A can be further suppressed.

[0077] In this manner, in this embodiment, in addition to providing multiple connection portions 301A in one widening portion 332, the specific arrangement of these connection portions 301A is also devised to sufficiently suppress the occurrence of localized temperature increases.

[0078] The number of connecting portions 301A provided in one widening portion 332 may be three or more. In the example shown in Fig. 10, four connecting portions 301A are provided in one widening portion 332. Specifically, two pairs of connecting portions 301A aligned along a direction perpendicular to the arrow AR1 (dotted line DL) are provided in one widening portion 332. As in the examples of Figs. 9 and 10, it is sufficient that the multiple connecting portions 301A in the widening portion 332 include at least one pair of connecting portions 301A arranged to be aligned along a direction perpendicular to the direction from the center CT of the widening portion 332 toward the boundary portion BD.

[0079] In the example of Fig. 10, the distance between a pair of connecting parts 301A arranged along the dotted line DL is equal to each other in each set. As a result, the four connecting parts 301A are arranged at positions that are the vertices of a rectangle. With this configuration, it is possible to ensure sufficient bonding strength between the widening part 332 and the bypass layer 370 while maintaining a balance of the currents of the connecting parts 301A. The shape formed by connecting the centers of the four connecting parts 301A may be a rectangle as in this embodiment, or may be a square.

[0080] As described above, the widened portion 332 etc. may be formed at the end of the linearly extending heat generating portion 331, but may also be formed at a position midway along the heat generating portion 331. FIG. 11 shows an example of the arrangement of the connection portion 301A in the widened portion 332 formed at a position midway along the heat generating portion 331. In this example, two boundaries BD are adjacent to one widened portion 332. One of the boundaries BD is also referred to below as the "first boundary BD1." The other boundary BD is also referred to below as the "second boundary BD2."

[0081] 11 indicates the direction from the first boundary BD1 to the second boundary BD2. The "direction from the first boundary BD1 to the second boundary BD2" specifically refers to the direction from the center in the width direction of the first boundary BD1 to the center in the width direction of the second boundary BD2.

[0082] In the example of Fig. 11, each connection portion 301A is arranged so that a dotted line DL extends in a direction perpendicular to the direction indicated by the arrow AR2. That is, the multiple connection portions 301A in the widened portion 332 of Fig. 11 include a pair of connection portions 301A arranged to line up along a direction perpendicular to the direction from the first boundary portion BD1 toward the second boundary portion BD2 (i.e., the direction of the dotted line DL). In the example of Fig. 11, there are two such pairs of connection portions 301A, and similarly to the example of Fig. 10, the four connection portions 301A are arranged at positions that become the vertices of a rectangle. There may be only one pair of connection portions 301A arranged along the direction of the dotted line DL.

[0083] The direction of the arrow AR2 can be said to be the direction in which the current flowing along the linear heat generating portion 331 flows when passing through the widened portion 332. In the example of Fig. 11, a pair of connecting portions 301A are arranged in a direction perpendicular to this direction (i.e., the direction of the dotted line DL), so that the currents flowing from the connecting portions 301A to the heat generating portion 331 are made approximately uniform.

[0084] In addition, in a widening portion 332 having two boundaries BD as shown in Fig. 11, the connecting portions 301A may be arranged in the same manner as in the example of Fig. 9. In this case, a pair of connecting portions 301A in the widening portion 332 may be arranged side by side along a direction perpendicular to a direction from a center CT of the widening portion 332 toward one of the boundaries BD (i.e., the direction of the dotted line DL).

[0085] Even when three or more boundaries BD are adjacent to one widening portion 332, the connection portions 301A may be arranged in a manner similar to any of the above-described examples. For example, in the example shown in FIG. 12, one more boundary BD (third boundary BD3) is added to the example in FIG. 11, but the other configuration is the same as the example in FIG. 11. In this way, when three boundaries BD are adjacent to one widening portion 332, a pair of connection portions 301A may be arranged in a manner similar to the example in FIG. 10, regardless of the third boundary BD3. The connection portions 301A may be arranged in a manner similar to the example in FIG. 9.

[0086] The shape of the widening portion 332 in top view may be other than circular. In the example of Fig. 13, the shape of the widening portion 332 is elongated along the dotted line DL, and this is the only point that differs from the example of Fig. 9. When one of a pair of connection portions 301A arranged along the dotted line DL is designated as a "first connection portion" and the other is designated as a "second connection portion," the widening portion 332 in Fig. 13 is formed to extend from the first connection portion toward the second connection portion.

[0087] In such a configuration, the shape of the widened portion 332 can be made to have a minimum area while including each of the connection portions 301A. The widened portion 332 is a portion of the heat generating portion 331 that generates a relatively small amount of heat. Since the size of the widened portion 332 is kept to a minimum, the heat generating efficiency of the heater unit 300 can be sufficiently ensured.

[0088] The number of connecting portions 301A provided in the widening portion 332 shaped as in Fig. 13 may be three or more. For example, as in the example of Fig. 10, four connecting portions 301A may be provided and arranged at positions that form the vertices of a rectangle. In this case, the connecting portions 301A are arranged so that the shape formed by connecting the centers of the four connecting portions 301A forms a rectangle, and the widening portion 332 is shaped to extend along the long side of the rectangle.

[0089] Although the arrangement of the connecting portion 301A in the widened portion 332 has been described above, the same configuration as above can be adopted for the arrangement of the connecting portion 301A in the widened portion 333. In addition, the same configuration as above can be adopted for the configuration of the connecting portion between the main heater layer 350 and the bypass layer 370.

[0090] In the above, a configuration has been described in which a heater for heating the dielectric substrate 100 is provided outside the dielectric substrate 100 in a state where it is unitized as the heater unit 300. However, the above-described configuration can also be applied to a configuration in which a heater is provided inside the dielectric substrate 100.

[0091] That is, the heat generating portion 331 made of a conductor drawn in a linear shape may be embedded inside the dielectric substrate 100 as a heater. In this case, the power supply portion 390 is provided on the surface 120 side of the dielectric substrate 100, and the bypass layer 370 connecting the power supply portion 390 and the heat generating portion 331 is embedded inside the dielectric substrate 100 like the heat generating portion 331. The connection between the bypass layer 370 and the heat generating portion 331 may be made through a long and thin via (hole) filled with a conductor, not through the welded portion 301 as in this embodiment. In addition, the arrangement of the portion of the widened portion 332 etc. to which the above-mentioned via is connected (i.e., the portion corresponding to the connection portion 301A) may be configured to be the same as any of the examples described above.

[0092] 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]

[0093] 10: Electrostatic chuck 100: Dielectric substrate 300: Heater unit 301A: Connection part 331, 351: Heat generating part 332, 333, 352, 353: Widening section 370: Bypass layer 390: Power supply unit BD: Boundary part BD1: 1st boundary BD2: 2nd boundary

Claims

1. A dielectric substrate; a heater for heating the dielectric substrate, The heater is A power supply unit that receives power from an external source; a heat generating portion which is a conductor laid out in a linear shape and generates heat by receiving power from the power supply portion; A bypass portion that connects the power supply portion and the heat generating portion, The heat generating portion has a widened portion, which is a portion where the line width is locally expanded, The bypass section includes: Electrostatic chuck, characterized in that the widened portion is connected to the heat generating portion at a plurality of points.

2. A boundary portion is a boundary portion between the widened portion and other portions of the heat generating portion, When the portion of the widening portion to which the bypass portion is connected is defined as a connection portion, The plurality of connection portions in the widening portion are 2 . The electrostatic chuck according to claim 1 , further comprising a pair of said connection portions arranged side by side along a direction perpendicular to a direction from a center of said widening portion toward said boundary portion.

3. A boundary portion is a boundary portion between the widened portion and other portions of the heat generating portion, When the portion of the widening portion to which the bypass portion is connected is defined as a connection portion, A plurality of the boundaries including the first boundary and the second boundary are adjacent to one of the widened portions, The plurality of connection portions in the widening portion include 2 . The electrostatic chuck according to claim 1 , further comprising a pair of the connection portions arranged side by side along a direction perpendicular to a direction from the first boundary portion toward the second boundary portion.

4. When the portion of the widening portion to which the bypass portion is connected is defined as a connection portion, the plurality of connection portions in the widened portion include a first connection portion and a second connection portion, The electrostatic chuck according to claim 1 , wherein the widened portion is formed so as to extend from the first connection portion toward the second connection portion.

5. In the widening portion, 5. The electrostatic chuck according to claim 2, wherein the four connection portions are disposed at positions corresponding to vertices of a rectangle.

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