Electrostatic chuck

Abstract

Provided is an electrostatic chuck capable of performing precise temperature adjustment by a heater. An electrostatic chuck 10 comprises a dielectric substrate 100 and a heater unit 300 that heats the dielectric substrate 100. In a top view, the heater unit 300 has heating parts 331 that are respective conductors routed individually and linearly in a plurality of regions HA divided so as not to overlap each other. The plurality of regions HA include a first region HA1 disposed at a position on the outermost peripheral side, and a second region HA2 disposed at a position on the inner peripheral side of the first region HA1. The line width of the heating part 331 routed in the first region HA1 is smaller than the line width of the heating part 331 routed in the second region HA2.

Description

Electrostatic chuck

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

[0002] For example, in a semiconductor manufacturing apparatus such as an etching apparatus, an electrostatic chuck is provided as a device for adsorbing and holding a substrate such as a silicon wafer to be processed. The electrostatic chuck has a dielectric substrate provided with adsorption electrodes. When a voltage is applied to the adsorption electrodes, an electrostatic force is generated, and the substrate placed on the dielectric substrate is adsorbed and held.

[0003] During the processing of the substrate, it is required to make the in-plane temperature distribution of the substrate as uniform as possible. In order to be able to adjust the in-plane temperature distribution of the substrate with high precision, in recent years, an electrostatic chuck equipped with a heater has also been developed and is already in practical use. The heater may be provided outside the dielectric substrate in a unitized state as described in Patent Document 1 below, or may be provided inside the dielectric substrate. In any configuration, the heater has a heating portion that is a conductor routed linearly. The heating portion is not provided only once in the entire heater, but is often routed individually in each of a plurality of regions.

[0004] Japanese Patent Application Laid-Open No. 2022-55292

[0005] During processing, the temperature of the substrate particularly tends to rise in the outer peripheral portion of the substrate. Also, the variation in the in-plane temperature distribution particularly tends to be large in the outer peripheral portion of the substrate. Therefore, it is necessary to particularly precisely perform temperature adjustment by the heater directly below the outer peripheral portion of the substrate.

[0006] By the way, for example, due to manufacturing defects of the heater or the like, the line width of the heating portion may locally become narrow or locally become wide in some parts. If such an abnormal line width occurs directly below the outer peripheral portion of the substrate, it may become difficult to precisely adjust the temperature by the heater.

[0007] The present invention has been made in view of such problems, and an object thereof is to provide an electrostatic chuck capable of precisely adjusting the temperature by a heater.

[0008] To solve the above problems, the electrostatic chuck according to the present invention comprises a dielectric substrate having a mounting surface on which an object to be adsorbed is placed, and a heater for heating the dielectric substrate. When viewed from a direction perpendicular to the mounting surface, the heater has heating elements, which are conductors, individually and linearly routed in each of a plurality of regions that are separated so as not to overlap each other. The plurality of regions include a first region located at the outermost position and a second region located at a position closer to the inner circumference than the first region. In this electrostatic chuck, the wire width of the heating element routed in the first region is smaller than the wire width of the heating element routed in the second region.

[0009] In the outermost first region, by reducing the line width of the heat-generating elements, it is possible to increase the number of heat-generating elements passing through a unit area. As a result, even if an abnormality in line width occurs at a specific location of a heat-generating element, causing the amount of heat generated at that location to deviate from the design value, local temperature changes can be suppressed because there are other normal heat-generating elements nearby. Consequently, it becomes possible to precisely control the temperature of the outermost part of the substrate.

[0010] Furthermore, by increasing the line width of the heating element in the inner second region, it becomes easier to form the heating element throughout the heater compared to the case where the line width of all heating elements is reduced.

[0011] According to the present invention, it is possible to provide an electrostatic chuck capable of precise temperature control using a heater.

[0012] This is a schematic cross-sectional view showing the configuration of the electrostatic chuck according to the first embodiment. This is a schematic exploded assembly view showing the configuration of the heater unit in Figure 1. This is a diagram showing an example of the arrangement of the sub-heater layer in the heater unit of Figure 1. This is a diagram showing the configuration of the sub-heater layer in the heater unit of Figure 1. This is a diagram showing an example of the arrangement of the main heater layer in the heater unit of Figure 1. This is a diagram showing the configuration of the main heater layer in the heater unit of Figure 1. This is a diagram for explaining the role of the bypass layer, etc. This is a diagram showing an example of the arrangement of the main heater layer in the heater unit according to the second embodiment. This is a diagram showing the configuration a heater unit according to a comparative example.

[0013] This embodiment will now be described with reference to the attached drawings. To facilitate understanding of the explanation, the same reference numerals are used for identical components in each drawing whenever possible, and redundant explanations are omitted.

[0014] A first embodiment will be described. The electrostatic chuck 10 according to this embodiment is used to attract and hold a substrate W to be processed by electrostatic force 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 also be used in apparatus other than semiconductor manufacturing apparatus.

[0015] Figure 1 shows a schematic cross-sectional view of the electrostatic chuck 10 in a state where the substrate W is adsorbed and held. The electrostatic chuck 10 comprises a dielectric substrate 100, a base plate 200, and a heater unit 300.

[0016] The dielectric substrate 100 is a substantially disc-shaped member made of a ceramic sintered body. The dielectric substrate 100 is made of, for example, high-purity aluminum oxide (Al ２ O ３ ) may include other materials. The purity, type, and additives of the ceramics in the dielectric substrate 100 can be appropriately set considering the plasma resistance and other properties required for the dielectric substrate 100 in semiconductor manufacturing equipment.

[0017] The upper surface 110 of the dielectric substrate 100 in Figure 1 is the "mounting surface" on which the substrate W is placed. The lower surface 120 of the dielectric substrate 100 in Figure 1 is the "bonded surface" that is bonded to the heater unit 300 via the bonding layer 410. The viewpoint from which the electrostatic chuck 10 is viewed from the surface 110 side, along a direction perpendicular to surface 110, will also be referred to as the "top view" below.

[0018] An adsorption electrode 130 is embedded inside the dielectric substrate 100. The adsorption electrode 130 is a thin, flat layer made of a metallic material such as tungsten, and is arranged parallel to the surface 110. In addition to tungsten, molybdenum, platinum, palladium, etc. may be used as the material for the adsorption electrode 130. 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. The adsorption electrode 130 may be provided as a single "monopolar" electrode as in this embodiment, or it may be provided as two "bipolar" electrodes.

[0019] As shown in Figure 1, a space SP is formed between the dielectric substrate 100 and the substrate W. When etching or other processes are performed in the semiconductor manufacturing apparatus, helium gas for temperature control is supplied to the space SP from the outside through a gas hole (not shown). By interposing helium gas between the dielectric substrate 100 and the substrate W, the thermal resistance between them is adjusted, thereby maintaining the temperature of the substrate W at an appropriate temperature. Note that the gas supplied to the space SP for temperature control may be a different type of gas than helium.

[0020] A sealing ring 111 and dots 112 are provided on the mounting surface 110, and the space SP described above is formed around them.

[0021] The seal ring 111 is a wall that partitions the space SP at its outermost position. The upper end of the seal ring 111 is part of the surface 110 and contacts the substrate W. Multiple seal rings 111 may be provided to divide the space SP. This configuration allows for individual adjustment of the helium gas pressure in each space SP, making the surface temperature distribution of the substrate W more uniform during processing.

[0022] In Figure 1, the portion labeled "116" is the bottom surface of space SP. Hereafter, this portion will also be referred to as "bottom surface 116". The seal ring 111, along with the dot 112 described below, is formed as a result of excavating a portion of surface 110 down to the position of bottom surface 116.

[0023] The dots 112 are circular protrusions that extend from the bottom surface 116. Multiple 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 is part of the surface 110 and contacts the substrate W. By providing multiple such dots 112, the bending of the substrate W is suppressed.

[0024] The base plate 200 is a substantially disc-shaped member that supports the dielectric substrate 100 and the heater unit 300. The base plate 200 is made of a metallic material such as aluminum. Of the base plate 200, the upper surface 210 in Figure 1 is the "bonded surface" that is bonded to the heater unit 300 via the bonding layer 420.

[0025] A refrigerant channel 250 for circulating refrigerant is formed inside the base plate 200. When etching or other processes are performed in the semiconductor manufacturing apparatus, refrigerant is supplied from the outside to the refrigerant channel 250, thereby cooling the base plate 200. During processing, the heat generated in the substrate W is transferred to the refrigerant 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 refrigerant. The supply and discharge of refrigerant to and from the refrigerant channel 250 is performed through an opening (not shown) formed on the surface 220 of the base plate 200 opposite to the surface 210.

[0026] An insulating film may be formed on the surface of the base plate 200. As the insulating film, for example, an alumina film formed by thermal spraying can be used. By covering the surface of the base plate 200 with an insulating film, the dielectric strength of the base plate 200 can be increased.

[0027] The heater unit 300 receives power from an external source to generate heat and heat the dielectric substrate 100. As will be explained later, the heater unit 300 is provided with multiple heat-generating parts 331, etc., and the amount of heat generated in each heat-generating part 331, etc. can be individually adjusted. By individually adjusting the amount of heat generated in each part, the in-plane temperature distribution of the substrate W during processing can be made more uniform.

[0028] The heater unit 300 is sandwiched between the dielectric substrate 100 and the base plate 200, and is bonded to each of them. The heater unit 300 is bonded to the dielectric substrate 100 via a bonding layer 410, and the heater unit 300 is bonded to the base plate 200 via a bonding layer 420. The bonding layers 410 and 420 are layers formed by curing, for example, a silicone adhesive. Multiple particulate fillers are arranged inside each to increase thermal conductivity. As the filler, for example, particles mainly composed of alumina can be used.

[0029] The specific configuration of the heater unit 300 will now be described. Figure 2 shows the configuration of the heater unit 300 as a schematic exploded assembly diagram. As shown in the figure, the heater unit 300 includes 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 terminal 390. In this embodiment, the sub-heater layer 330, the main heater layer 350, and the bypass layer 370 are arranged from top to bottom in Figure 2, but the order of arrangement may differ from that of this embodiment.

[0030] The support plates 310 are substantially disc-shaped members and are provided at both the upper and lower ends of the heater unit 300 as shown in Figure 2. The support plate 310 provided at the upper end of Figure 2 will hereinafter also be referred to as "support plate 310A". The support plate 310 provided at the lower end of Figure 2 will hereinafter also be referred to as "support plate 310B". Support plate 310A is the part that is bonded to the dielectric substrate 100 via the bonding layer 410, and support plate 310B is the part that is bonded to the base plate 200 via the bonding layer 420.

[0031] The pair of support plates 310A and 310B are members that reinforce the entire heater unit 300 by sandwiching the entire sub-heater layer 330, main heater layer 350, and bypass layer 370 between them. In this embodiment, both support plates 310A and 310B are made of metal, but they may be made of other materials (for example, insulating materials). Note that each member of the heater unit 300, such as the support plates 310, has multiple through holes such as gas holes and lift pin holes, but these are not shown in Figure 2.

[0032] The insulating layer 320 is provided between the support plate 310A and the sub-heater layer 330, and is a layer for electrically insulating the two. The insulating layer 320 also serves to physically join the two. In this embodiment, the insulating layer 320 is a polyimide film, but it may contain components other than polyimide, and may be formed from a material different from polyimide. If the support plate 310A is made of an insulating material, the insulating layer 320 can be omitted.

[0033] The subheater layer 330 is the part that generates heat by receiving power from an external source. In Figure 2, the subheater layer 330 is schematically depicted as a single disc, but in reality, the subheater layer 330 is divided into multiple regions that do not overlap when viewed from above, and each region can be heated individually. The specific configuration of the subheater layer 330 will be explained later.

[0034] The insulating layer 340 is provided between the sub-heater layer 330 and the main heater layer 350, and is a layer for electrically insulating the two. The insulating layer 340 also plays a role in physically joining the two. In this embodiment, the insulating layer 340 is a polyimide film, but it may contain components other than polyimide, and may be formed from a material different from polyimide.

[0035] The main heater layer 350, like the sub-heater layer 330 mentioned earlier, is a part that generates heat by receiving power from an external source. In Figure 2, the main heater layer 350 is schematically depicted as a single disc, but in reality, the main heater layer 350 is divided into multiple regions that do not overlap when viewed from above, and each region can be heated individually. The specific configuration of the main heater layer 350 will be explained later.

[0036] The main heater layer 350 generates more heat per unit area than the sub-heater layer 330 described above. The main heater layer 350 is intended to raise the overall temperature of the dielectric substrate 100 in a short time. The sub-heater layer 330 is intended to adjust the temperature of each part of the dielectric substrate 100 and to make the in-plane temperature distribution of the substrate W more uniform. Thus, in this embodiment, two heater layers are provided separately according to their respective roles. Alternatively, only one of the main heater layer 350 and the sub-heater layer 330 may be provided, and the other may not be provided.

[0037] The insulating layer 360 is provided between the main heater layer 350 and the bypass layer 370, and serves to electrically insulate them from each other. The insulating layer 360 also plays a role in physically joining the two layers. In this embodiment, the insulating layer 360 is a polyimide film, but it may contain components other than polyimide, and may be formed from a material different from polyimide.

[0038] The bypass layer 370 is a layer for electrically connecting the power supply terminal 390 (described later) to the sub-heater layer 330 or the main heater layer 350. In Figure 2, the bypass layer 370 is schematically depicted as a single disc, but in reality, the bypass layer 370 is divided into multiple parts. By providing the bypass layer 370 in the middle of the electrical circuit connected to the sub-heater layer 330, etc., it becomes possible to adjust the position of the power supply terminal 390. Each of the divided bypass layers 370 is electrically connected to either the sub-heater layer 330 or the main heater layer 350 in part.

[0039] The insulating layer 380 is provided between the bypass layer 370 and the support plate 310B, and is a layer for electrically insulating the two. The insulating layer 380 also serves to physically join the two. In this embodiment, the insulating layer 380 is a polyimide film, but it may contain components other than polyimide, and may be formed from a material different from polyimide. If the support plate 310B is made of an insulating material, the insulating layer 380 can be omitted.

[0040] During the manufacturing of the heater unit 300, the layers shown in Figure 2 are stacked and the entire unit is pressurized and heated. As a result, the entire unit is joined together as a single unit via the insulating layer 320, which is a polyimide film.

[0041] The power supply terminal 390 is the part that receives the power necessary to generate heat in the subheater layer 330 and the like from an external source. In this embodiment, the power supply terminal 390 is formed as an elongated rod-shaped plug, with one end connected to the bypass layer 370. Multiple power supply terminals 390 are provided according to the number of bypass layers 370, but only two of them are shown in Figure 2. Through holes (not shown) are formed in the base plate 200 at positions corresponding to the power supply terminals 390, and the power supply terminals 390 are inserted through these through holes.

[0042] The configuration of the sub-heater layer 330 will be described. As described above, the sub-heater layer 330 is divided into a plurality of regions, and it is possible to generate heat individually in each region. FIG. 3 shows an example of the way of dividing the sub-heater layer 330 in a top view. In this example, the sub-heater layer 330 is divided into a total of 24 regions HA.

[0043] As shown in FIG. 4, the sub-heater layer 330 is configured as a linear heating portion 331, and is individually routed in each region HA. That is, a total of 24 heating portions 331 are provided in the present embodiment. The heating portion 331 is a portion that generates heat by receiving power supply from the outside.

[0044] Among the plurality of regions HA shown in FIG. 3, the region arranged at the outermost peripheral position is hereinafter also referred to as "first region HA1". Further, the region arranged at a position closer to the inner peripheral side than the first region HA1 is hereinafter also referred to as "second region HA2". In the present embodiment, the second region HA2 is a region HA arranged adjacent to the first region HA1 in the radial direction. The first region HA1 and the second region HA2 do not have to be adjacent to each other in the radial direction.

[0045] A plurality of first regions HA1 of the present embodiment are provided, and these are arranged so as to be arranged in the circumferential direction. The shapes of the respective first regions HA1 are the same as each other. In the present embodiment, all of the plurality of regions HA arranged at the outermost peripheral position are the first regions HA1 having the same shape as each other. Instead of such a mode, a first region HA1 having a different shape from the others may be provided among the plurality of first regions HA1 arranged at the outermost peripheral position.

[0046] Similarly, a plurality of second regions HA2 of the present embodiment are provided, and they are arranged side by side in the circumferential direction. The shapes of the respective second regions HA2 are identical to each other. In the present embodiment, all of the plurality of regions HA arranged at a position one inside the first region HA1 are second regions HA2 having the same shape as each other. Instead of such a mode, a second region HA2 having a shape different from the others may be provided among the plurality of second regions HA2 arranged at a position one inside the first region HA1.

[0047] FIG. 4 shows an example of a pair of first regions HA1 and second regions HA2, and the heating portions 331 routed in the respective regions HA. In each region HA, one linear heating portion 331 is routed along a path that evenly passes through substantially all of its range.

[0048] Circular pad portions 332 and 333 are formed at both ends of the heating portion 331, respectively. The heating portion 331 and the pad portions 332 and 333 are formed, for example, by etching a thin metal foil, and the whole 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.

[0049] Note that the shape of the heating portion 331 shown in FIG. 4 is schematic and is different from the actual shape. The same applies to the positions of the pad portions 332 and 333.

[0050] In FIG. 4, the symbol "D11" is attached to the dimension of the first region HA1 along the radial direction. Also, in the same figure, the symbol "D12" is attached to the dimension of the second region HA2 along the radial direction. Hereinafter, each will also be referred to as "dimension D11", "dimension D12". In the present embodiment, dimension D11 and dimension D12 are equal to each other.

[0051] As shown in Figure 4, the line width of the heat-generating section 331 routed within the first region HA1 is smaller than the line width of the heat-generating section 331 routed within the second region HA2 inside it. Here, "line width" refers to the dimensions of the heat-generating section 331 in a direction perpendicular to the direction in which the heat-generating section 331 extends.

[0052] In each region HA, there are multiple portions of the heat-generating element 331 that extend in the circumferential direction, and these portions are arranged so that they are aligned radially. In the first region HA1, the number of portions of the heat-generating element 331 that extend in the circumferential direction, that is, the number of portions arranged radially, is "9". In the second region HA2, the number of portions of the heat-generating element 331 that extend in the circumferential direction, that is, the number of portions arranged radially, is "5".

[0053] In the first region HA1, nine heating elements 331 are arranged within the range of dimension D11. In the second region HA2, five heating elements 331 are arranged within the range of dimension D12. Dimensions D11 and D12 are equal to each other. Therefore, the arrangement density of heating elements 331 in the first region HA1 is higher than the arrangement density of heating elements 331 in the second region HA2. Here, "arrangement density" refers to the number of heating elements 331 arranged per unit length in a direction perpendicular to the direction in which the heating elements 331 extend (the radial direction in the example of Figure 4). Among the multiple regions HA, the line width and arrangement density of heating elements 331 in the other regions HA located on the inner circumference side of the second region HA2 are the same as the line width and arrangement density of heating elements 331 in the second region HA2.

[0054] The configuration of the main heater layer 350 will now be described. Similar to the sub-heater layer 330, the main heater layer 350 is also divided into multiple regions, and it is possible to generate heat individually in each region. Figure 5 shows an example of how the main heater layer 350 is divided, in a top view. In this example, the main heater layer 350 is divided into a total of three regions HB.

[0055] As shown in Figure 6, the main heater layer 350 is configured as linear heating elements 351, which are individually routed within each region HB. In other words, in this embodiment, a total of three heating elements 351 are provided. Each heating element 351 is a part that generates heat by receiving power from an external source.

[0056] In Figure 5, the region located at the outermost position among the multiple regions HB is hereinafter referred to as "first region HB1". The region located at an inner circumference position relative to the first region HB1 is hereinafter referred to as "second region HB2". In this embodiment, the second region HB2 is a region HB located adjacent to the first region HB1 in the radial direction. The first region HB1 and the second region HB2 do not necessarily have to be adjacent to each other in the radial direction.

[0057] In this embodiment, the first region HB1 is a single annular region. Similarly, the second region HB2 is also a single annular region. The centers of the first region HB1 and the second region HB2 coincide when viewed from above.

[0058] In Figure 5, the dotted lines between each region HB completely overlap with the dotted lines between each region HA in Figure 3 that extend circumferentially (i.e., are circular). Therefore, in a top view, the first region HB1 completely overlaps with the entirety of multiple first regions HA1. Similarly, in a top view, the second region HB2 completely overlaps with the entirety of multiple second regions HA2.

[0059] Figure 6 shows an example of a first region HB1 and a second region HB2, and the heat-generating section 351 routed within each region HB. In each region HB, a single linear heat-generating section 351 is routed along a path that passes through almost the entire area equally. Furthermore, most of the heat-generating section 351 is formed to extend in an annular shape along the circumferential direction.

[0060] Circular pad portions 352 and 353 are formed at each end of the heating element 351. The heating element 351 and the pad portions 352 and 353 are formed, for example, by etching a thin metal foil, and the whole structure functions as a single main heater layer 350. In other words, one main heater layer 350 is provided for each of the three regions HB.

[0061] Note that the shape of the heating element 351 shown in Figure 6 is schematic and differs from the actual shape. The same applies to the positions of the pads 352 and 353.

[0062] In Figure 6, the reference numeral "D21" indicates the dimension of the first region HB1 along the radial direction. Similarly, the reference numeral "D22" indicates the dimension of the second region HB2 along the radial direction. Hereafter, these will also be referred to as "dimension D21" and "dimension D22," respectively. In this embodiment, dimensions D21 and D22 are equal to each other.

[0063] As shown in Figure 6, the line width of the heating element 351 routed in the first region HB1 is smaller than the line width of the heating element 351 routed in the second region HB2 inside it. Here, "line width" refers to the dimensions of the heating element 351 in a direction perpendicular to the direction in which the heating element 351 extends.

[0064] In each region HB, there are multiple portions of the heating element 351 that extend in the circumferential direction, and these portions are arranged so that they are aligned radially. In the first region HB1, the number of portions of the heating element 351 that extend in the circumferential direction, that is, the number of portions arranged radially, is "6". In the second region HB2, the number of portions of the heating element 351 that extend in the circumferential direction, that is, the number of portions arranged radially, is "4".

[0065] In the first region HB1, six heating elements 351 are arranged within the range of dimension D21. In the second region HB2, four heating elements 351 are arranged within the range of dimension D22. Dimensions D21 and D22 are equal to each other. Therefore, the arrangement density of heating elements 351 in the first region HB1 is higher than the arrangement density of heating elements 351 in the second region HB2. Here, "arrangement density" refers to the number of heating elements 351 arranged per unit length in a direction perpendicular to the direction in which the heating elements 351 extend (the radial direction in the example of Figure 6). Among the multiple regions HB, the line width and arrangement density of heating elements 351 in other regions HB not shown in Figure 6 are the same as the line width and arrangement density of heating elements 351 in the second region HB2.

[0066] Figure 7 shows a schematic perspective view of the configuration of two regions HA, two sub-heater layers 330 arranged within them, and a bypass layer 370 connected to the sub-heater layers 330. One of the two regions HA shown in Figure 7 will be referred to as "region HA11" below. The other region HA will be referred to as "region HA12" below. Note that the shape of the heating element 331 etc. shown in Figure 7 is schematic and differs from the actual shape.

[0067] As mentioned earlier, the bypass layer 370 is divided into multiple parts. In Figure 7, only three of the divided bypass layer 370 are shown. Of the three divided bypass layer 370, the one labeled "371" in Figure 7 is positioned so as to overlap with only one region HA in a top view. In other words, it is individually positioned directly beneath each region HA. The portion of the bypass layer 370 that is positioned in this manner will also be referred to as "bypass layer 371" below.

[0068] Of the divided bypass layers 370, the one labeled "372" in Figure 7 is positioned to overlap with both region HA11 and region HA12 in a top view. This portion of the bypass layer 370 will also be referred to as "bypass layer 372" below.

[0069] In the subheater layer 330 located in region HA11, a pad portion 332 at one end of the heating element 331 is electrically connected to the bypass layer 371 directly below it. A pad portion 333 at the other end of the heating element 331 is electrically connected to the bypass layer 372.

[0070] The same applies to the subheater layer 330 located in region HA12, where a pad portion 332 at one end of the heating element 331 is electrically connected to the bypass layer 371 directly below it. A pad portion 333 at the other end of the heating element 331 is electrically connected to the bypass layer 372.

[0071] Furthermore, the electrical connections of each part as described above are achieved, for example, by welding the upper and lower layers together. To make the configuration easier to understand, in Figure 7, each welded part is schematically depicted as a rod-shaped member extending in a straight line (the part labeled 301). In the parts that overlap with each welded part in the top view, openings are formed in each of the layers between the subheater layer 330 and the bypass layer 370 (insulating layer 340, main heater layer 350, and insulating layer 360), and the subheater layer 330 and the bypass layer 370 are directly connected through these openings.

[0072] The subheater layer 330 and the bypass layer 370 may be electrically connected by welding, as in this embodiment, but they may also be electrically connected by other means. For example, they may be electrically connected via a conductive member extending vertically. In either configuration, an electrical circuit, denoted by reference numeral 301 in Figure 7, is formed between the subheater layer 330 and the bypass layer 370. This electrical circuit will also be referred to as "electrical circuit 301" below.

[0073] One end of a power supply terminal 390 is connected to each bypass layer 371 from the bottom of Figure 7. A voltage is individually applied to each of these power supply terminals 390 from an external DC power supply. Similarly, one end of a power supply terminal 390 is also connected to the bypass layer 372 from the bottom of Figure 7. This power supply terminal 390 is grounded. Note that the DC power supply and grounding shown in Figure 7 are part of a temperature control circuit that is connected to the electrostatic chuck 10 from the outside.

[0074] As described above, each subheater layer 330 provided in each region HA has one pad portion 332 connected to an individual DC power supply via a bypass layer 371, and the other pad portion 333 is grounded via a common bypass layer 372. Other subheater layers 330 not shown in Figure 7 are also connected to a DC power supply in a similar configuration. This configuration makes it possible to supply power individually to each of the multiple subheater layers 330 and adjust the amount of heat generated in each part.

[0075] It is also possible to supply power to the subheater layer 330 directly from the power supply terminal 390 without going through the bypass layer 370. However, by configuring the power supply to go through the bypass layer 370 as in this embodiment, it becomes possible to increase the flexibility of the placement of the power supply terminal 390 and to consolidate the grounded power supply terminal 390 into one.

[0076] The power supply to each main heater layer 350 is also realized by the same configuration as described above. The specific configuration is the same as that shown in Figure 7, so its explanation and illustration are omitted.

[0077] Incidentally, when substrate W is being processed in semiconductor manufacturing equipment, the temperature of substrate W tends to rise particularly easily in its outer peripheral portion. Also, variations in the in-plane temperature distribution of substrate W tend to be particularly large in the outer peripheral portion of substrate W. Therefore, it is necessary to precisely control the temperature using the heater unit 300 directly beneath the outer peripheral portion of substrate W. In other words, it is necessary to precisely control the amount of heat generated in each part of the first region HA1 and the first region HB1.

[0078] However, due to manufacturing defects or other reasons, the line width of the heating elements 331 and 351 may become locally narrower or wider in some areas. When such abnormalities in line width occur, the amount of heat generated at that location will deviate from the design value. In particular, if abnormalities in the line width of the heating elements 331, etc., occur in the location directly below the outer periphery of the substrate W, i.e., in the first region HA1 or first region HB1, it may become difficult to precisely control the temperature by the heater unit 300.

[0079] Therefore, in this embodiment, as previously mentioned, the line width of the heat-generating section 331 routed in the first region HA1 is made smaller than the line width of the heat-generating section 331 routed in the second region HA2. Similarly, the line width of the heat-generating section 351 routed in the first region HB1 is made smaller than the line width of the heat-generating section 351 routed in the second region HB2.

[0080] In the outermost first region HA1, by reducing the line width of the heat-generating portion 331, the number of heat-generating portions 331 passing through a unit area can be increased, as in this embodiment. In other words, the density of heat-generating portions 331 can be increased. As a result, even if an abnormality in line width occurs at a specific location of the heat-generating portion 331, causing the amount of heat generated at that location to deviate from the design value, local temperature changes can be suppressed because there are other normal heat-generating portions 331 nearby. As a result, it becomes possible to precisely control the temperature of the outermost portion of the substrate W.

[0081] As a measure to suppress the effects of abnormal line width, for example, it is conceivable to uniformly reduce the line width of all heating elements 331 provided in the heater unit 300, not just the line width of the heating element 331 routed in the first region HA1. However, in that case, there is a concern that the effort and cost required to form the heating elements 331 will increase. Therefore, as in this embodiment, by making the line width of the heating element 331 larger in the second region HA2 on the inner circumference side, the formation of the heating elements 331 throughout the heater unit 300 becomes easier compared to the case where the line width of all heating elements 331 is reduced.

[0082] The effects of having a smaller line width and higher arrangement density for the heat-generating elements 351 routed in the first region HB1 compared to the heat-generating elements 351 routed in the second region HB2 are the same as described above.

[0083] In this embodiment, the line widths of both the heating element 331 and the heating element 351 are reduced and their placement density is increased at a position directly beneath the outer peripheral portion of the substrate W. Alternatively, at a position directly beneath the outer peripheral portion of the substrate W, the line width of only one of the heating element 331 and the heating element 351 may be reduced, and their placement density may be increased.

[0084] Furthermore, if there are areas on the substrate W where the temperature tends to be locally lower due to the structure of the electrostatic chuck 10, the line width of the heat-generating part 331, etc., that overlaps with such areas when viewed from above may be intentionally narrowed. By locally increasing the amount of heat generated by the heat-generating part 331, etc., in those areas, the in-plane temperature distribution of the substrate W can be made more uniform.

[0085] However, adjusting the amount of heat generated by changing the line width of the heat-generating section 331, etc., is often difficult. For example, even slightly reducing the line width of the heat-generating section 331, etc., in a part of it tends to cause a significant increase in the amount of heat generated in that part.

[0086] In such cases, the line width of the heat-generating elements 331, etc. can be narrowed locally while increasing the density of the heat-generating elements 331, etc., as in this embodiment. By increasing the density of the heat-generating elements 331, etc., the effect of narrowing the line width locally can be reduced. In other words, it becomes possible to reduce the amount of local temperature rise of the substrate W directly above the location in question, even while narrowing the line width locally.

[0087] Conversely, if there are areas on the substrate W where the temperature tends to rise locally, the line width of the heat-generating parts 331, etc., that overlap with those areas when viewed from above may be deliberately widened. Even in this case, the effect of widening the line width locally can be reduced by increasing the arrangement density of the heat-generating parts 331, etc. In other words, it becomes possible to widen the line width locally while reducing the amount of local temperature drop of the substrate W directly above that location.

[0088] The above describes a configuration in which the heater for heating the dielectric substrate 100 is provided outside the dielectric substrate 100 as a unitized heater unit 300. However, the above-described configuration can also be applied to a configuration in which the heater is provided inside the dielectric substrate 100.

[0089] In other words, the sub-heater layer 330, main heater layer 350, and bypass layer 370, similar to those in this embodiment, may be embedded inside the dielectric substrate 100, just like the adsorption electrode 130. In this case, the connection between the sub-heater layer 330, etc., and the bypass layer 370 may be made not by welding, but, for example, through holes (vias) filled with conductors. The same effects as in this embodiment can be achieved even in this embodiment.

[0090] The second embodiment will now be described. The following will primarily focus on the differences from the first embodiment, while common points will be omitted as appropriate.

[0091] In this embodiment, the division of the regions HB in the main heater layer 350 differs from that of the first embodiment. Figure 8 shows the arrangement of the main heater layer 350 in this embodiment, that is, the shape of each region HB, in the same manner as in Figure 5. As shown in Figure 8, in this embodiment, the main heater layer 350 is divided into a total of five regions HB, which are arranged in a concentric circle pattern.

[0092] In this embodiment, as in the first embodiment, the first region HB1, located at the outermost position, and the second region HB2, located at the inner position, are both annular regions when viewed from above. Furthermore, the centers of the first region HB1 and the second region HB2 coincide when viewed from above. However, the dimension D31 of the first region HB1 along the radial direction is smaller than the dimension D32 of the second region HB2 along the radial direction. As a result, the area of ​​the first region HB1 is smaller than the area of ​​the second region HB2.

[0093] The dimension D31 of the first region HB1 along the radial direction is smaller than the dimension of any other region HB along the radial direction. In other words, when comparing the radial dimensions of each region HB, the dimension is smallest in the outermost first region HB1.

[0094] As described above, when a substrate W is being processed in a semiconductor manufacturing apparatus, the temperature of the substrate W tends to rise particularly easily in the outer peripheral portion. Therefore, in this embodiment, by placing a first region HB1 with a narrow width (i.e., dimension D31) directly below the portion where the temperature tends to rise, it is possible to appropriately adjust the temperature of that portion. In other words, by adjusting the temperature of the outer peripheral portion of the substrate W, which tends to rise easily, separately from the rest of the substrate, it is possible to make the overall temperature distribution more uniform.

[0095] It is preferable to arrange the regions HB such that the dimension D31 of the first region HB1 along the radial direction is 1 / 2 or less of the dimension D32 of the second region HB2 along the radial direction. With this configuration, when performing precise temperature control on the outer periphery of the substrate W, the affected area (the area along the radial direction) can be limited to the minimum necessary range.

[0096] Figure 9 shows examples of the heat-generating section 351 routed in the first region HB1 and the heat-generating section 351 routed in the second region HB2. In each region HB, a single linear heat-generating section 351 is routed along a path that passes through almost the entire area equally. Furthermore, most of the heat-generating section 351 is formed to extend in an annular shape along the circumferential direction.

[0097] In this embodiment as well, the line width of the heat-generating section 351 routed within the first region HB1 is smaller than the line width of the heat-generating section 351 routed within the second region HB2 located inside it.

[0098] In each region HB, there are multiple portions of the heating element 351 that extend in the circumferential direction, and these portions are arranged so that they are aligned radially. In the first region HB1, the number of portions of the heating element 351 that extend in the circumferential direction, that is, the number of portions arranged radially, is "4". In the second region HB2, the number of portions of the heating element 351 that extend in the circumferential direction, that is, the number of portions arranged radially, is "4".

[0099] In the first region HB1, four heating elements 351 are arranged within the range of dimension D31. In the second region HB2, four heating elements 351 are arranged within the range of dimension D32. Dimension D31 is smaller than dimension D32. Therefore, in this embodiment as well, the arrangement density of heating elements 351 in the first region HB1 is higher than the arrangement density of heating elements 351 in the second region HB2. With this configuration, the same effects as those described in the first embodiment can be achieved.

[0100] Furthermore, among the multiple regions HB, the line width and arrangement density of the heat-generating elements 351 in regions HB not shown in Figure 9 are the same as those of the heat-generating elements 351 in the second region HB2. The second region HB2 may be a region HB adjacent to the first region HB1, as in this embodiment, but it may also be a region HB not adjacent to the first region HB1.

[0101] As in this embodiment, when the dimension D31 of the first region HB1 is reduced, the effect of reducing the line width of the heating element 351 in the first region HB1 becomes particularly significant. To explain the reason for this, the configuration of the comparative example will be described first. In the comparative example shown in Figure 10, the shapes of the first region HB1 and the second region HB2 are the same as in this embodiment. However, in this comparative example, the line width of the heating element 351 routed in the first region HB1 and the line width of the heating element 351 routed in the second region HB2 inside it are equal to each other. In other words, the line width of the heating element 351 routed in the first region HB1 is larger compared to this embodiment shown in Figure 9.

[0102] In this configuration, four heating elements 351 can be routed along the radial direction in the relatively wide second region HB2, whereas in the relatively narrow first region HB1, only one or two heating elements 351 can be routed along the radial direction.

[0103] Thus, when the dimension D31 of the first region HB1 is small, if the line width of the heating element 351 is not adjusted for each region HB, the degree of freedom in routing the heating element 351 in the first region HB1 becomes particularly small. It becomes difficult to route the heating element 351 along a path that passes evenly through the entire first region HB1, so the temperature difference between the parts of the first region HB1 that the heating element 351 passes through and the parts that it does not tend to be large. Furthermore, if a localized abnormality in line width occurs in the heating element 351 of the first region HB1, the impact on the in-plane temperature distribution of the substrate W becomes particularly large because there are no or few normal heating elements 351 in the vicinity.

[0104] Therefore, in the first region HB1, where dimension D31 is small, the effect of reducing the line width of the heating element 351 is particularly significant. By making the line width of the heating element 351 routed in the first region HB1 smaller than that of the heating element 351 routed in the second region HB2, the degree of freedom in routing the heating element 351 in the first region HB1 can be increased. As mentioned earlier, in the example of Figure 9, it is possible to route the same number (4) of heating elements 351 along the radial direction in both the first region HB1 and the second region HB2.

[0105] By reducing the line width of the heating element 351, it becomes possible to route the heating element 351 along a path that passes through the entire first region HB1 uniformly. In this embodiment, in addition to the effects described in the first embodiment, it is also possible to reduce the temperature difference in each part of the first region HB1 compared to the comparative example in Figure 10.

[0106] The configuration of the sub-heater layer 330 in this embodiment is the same as in the first embodiment, but it may differ from that of the first embodiment. Furthermore, the heater unit 300 may have a main heater layer 350 as in this embodiment, but may not have a sub-heater layer 330.

[0107] The embodiments have been described above with reference to specific examples. However, this disclosure is not limited to these specific examples. Modifications made to these specific examples by those skilled in the art are also included within the scope of this disclosure, as long as they retain the features of this disclosure. The elements, their arrangement, conditions, shapes, etc., of each of the aforementioned specific examples are not limited to those illustrated and can be modified as appropriate. The elements of each of the aforementioned specific examples can be combined in different ways as appropriate, as long as no technical inconsistencies arise.

[0108] 10: Electrostatic chuck 100: Dielectric substrate 110: Surface 300: Heater unit 331, 351: Heating part HA, HB: Region HA1, HB1: First region HA2, HB2: Second region W: Substrate

Claims

1. An electrostatic chuck comprising: a dielectric substrate having a mounting surface on which an object to be adsorbed is placed; and a heater for heating the dielectric substrate, wherein, when viewed from a direction perpendicular to the mounting surface, the heater has heating elements that are individual and linearly routed conductors in each of a plurality of regions that are separated so as not to overlap each other, the plurality of regions include a first region located at the outermost position and a second region located at a position on the inner side of the first region, and the line width of the heating element routed in the first region is smaller than the line width of the heating element routed in the second region.

2. The electrostatic chuck according to claim 1, characterized in that, when viewed from a direction perpendicular to the mounting surface, both the first region and the second region are annular regions, and their respective centers coincide with each other.

3. The electrostatic chuck according to claim 1, characterized in that the arrangement density of the heat-generating elements in the first region is higher than the arrangement density of the heat-generating elements in the second region.

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