Electrostatic chuck

Abstract

Provided is an electrostatic chuck that can equalize the in-plane temperature distribution of a substrate during processing. The 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 conductors routed individually and linearly in each of 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 circumferential side, and a second region HA2 disposed at a position closer to the inner circumferential side than the first region HA1. The area of the first region HA1 is smaller than the area of the second region HA2.

Description

Electrostatic chuck

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

[0002] For example, semiconductor manufacturing equipment such as etching equipment is provided with an electrostatic chuck 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, attracting and holding the substrate placed on the dielectric substrate.

[0003] During substrate processing, it is necessary to make the temperature distribution within the surface of the substrate as uniform as possible. In order to enable the temperature distribution within the surface of the substrate to be adjusted with high precision, electrostatic chucks equipped with heaters have been developed in recent years and are already in practical use. The heater may be provided outside the dielectric substrate as a unit, as described in Patent Document 1 below, for example, or may be provided inside the dielectric substrate. In either configuration, the heater has a heat-generating portion that is a conductor routed in a linear fashion. Often, the heat-generating portion is not provided in the entire heater, but is routed individually in each of multiple regions.

[0004] JP 2022-55292 A

[0005] The temperature of a substrate during processing tends to rise particularly at the outer periphery of the substrate. The in-plane temperature distribution also tends to vary significantly at the outer periphery of the substrate. However, in conventional electrostatic chucks, the division of the substrate into multiple regions for arranging heat generating elements was determined without taking into consideration the above-mentioned trends. Therefore, even if the amount of heat generated in each region was adjusted, it was sometimes difficult to achieve a uniform in-plane temperature distribution of the substrate.

[0006] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an electrostatic chuck that can make the temperature distribution within the surface of a substrate uniform during processing.

[0007] In order to solve the above problems, the present invention provides an electrostatic chuck including a dielectric substrate having a mounting surface on which an object to be attracted is mounted, and a heater for heating the dielectric substrate. When viewed from a direction perpendicular to the mounting surface, the heater has a plurality of regions divided so as not to overlap each other, each of which has a heat generating portion that is a conductor that is individually and linearly routed. The plurality of regions include a first region located at the outermost position and a second region located at a position more inward than the first region, and the area of ​​the first region is smaller than the area of ​​the second region.

[0008] In an electrostatic chuck configured as described above, a small-area first region is disposed directly below the outer peripheral portion of the substrate. As described above, the outer peripheral portion of the substrate is a portion where the temperature is particularly likely to rise, and where the in-plane temperature distribution is likely to vary significantly. By disposing a small-area first region directly below such a portion, it is possible to appropriately adjust the temperature of that portion. Furthermore, for example, it is possible to individually adjust the heat generation amount in each of the subdivided first regions, thereby finely adjusting the temperature in each portion of the substrate. As a result, local temperature increases and the like can be suppressed, and the in-plane temperature distribution of the substrate can be made uniform.

[0009] According to the present invention, it is possible to provide an electrostatic chuck that can make the temperature distribution within the surface of a substrate uniform during processing.

[0010] FIG. 2 is a cross-sectional view schematically showing the configuration of an electrostatic chuck according to a first embodiment; FIG. 3 is an exploded view schematically showing the configuration of the heater unit of FIG. 1; FIG. 4 is a view showing an example of the arrangement of sub-heater layers in the heater unit of FIG. 1; FIG. 5 is a view showing the configuration of one sub-heater layer; FIG. 6 is a view showing an example of the arrangement of main heater layers in the heater unit of FIG. 1; FIG. 7 is a view showing the configuration of one main heater layer; FIG. 8 is a view for explaining the role of a bypass layer, etc.; FIG. 9 is a view for explaining the positional relationship between the sub-heater layer and a refrigerant flow path; FIG. 10 is a view showing an example of the arrangement of sub-heater layers in a heater unit according to a second embodiment; FIG. 11 is a view showing an example of the arrangement of sub-heater layers in a heater unit according to a third embodiment; FIG. 12 is a view showing an example of the arrangement of sub-heater layers in a heater unit according to a fourth embodiment; FIG. 13 is a view showing the configuration of a main heater layer in a heater unit according to a comparative example;

[0011] Hereinafter, the present embodiment will be described with reference to the accompanying drawings. To facilitate understanding of the description, the same components in the drawings will be denoted by the same reference numerals as much as possible, and duplicated descriptions will be omitted.

[0012] A first embodiment will be described. An 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 also be used in apparatuses other than semiconductor manufacturing apparatuses.

[0013] 1 is a schematic cross-sectional view showing the configuration of an electrostatic chuck 10 in a state in which the electrostatic chuck 10 attracts and holds a substrate W. The electrostatic chuck 10 includes a dielectric substrate 100, a base plate 200, and a heater unit 300.

[0014] 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 ３The purity, type, and additives of the ceramics in the dielectric substrate 100 can be appropriately set in consideration of the plasma resistance and other properties required of the dielectric substrate 100 in semiconductor manufacturing equipment.

[0015] 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 also be referred to as a "top view."

[0016] 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 disposed parallel to the surface 110. In addition to tungsten, the adsorption electrode 130 may be made of molybdenum, platinum, palladium, or the like. When a voltage is applied to the adsorption electrode 130 from the outside via a power supply path (not shown), an electrostatic force is generated between the surface 110 and the substrate W, thereby attracting and holding the substrate W. Only one adsorption electrode 130 may be provided as a so-called "monopolar" electrode as in this embodiment, or two may be provided as so-called "bipolar" electrodes.

[0017] 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 to the space SP from the outside 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, thereby maintaining the temperature of the substrate W at an appropriate temperature. Note that the temperature adjustment gas supplied to the space SP may be a type of gas other than helium.

[0018] A seal ring 111 and dots 112 are provided on the surface 110, which is the mounting surface, and the space SP is formed around these.

[0019] 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.

[0020] 1, the portion marked with the reference numeral "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 portion of the surface 110 to the position of the bottom surface 116.

[0021] The dots 112 are circular protrusions that protrude 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 comes into contact with the substrate W. By providing a plurality of such dots 112, bending of the substrate W is suppressed.

[0022] 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. An upper surface 210 of the base plate 200 in FIG. 1 serves as a "bonded surface" that is bonded to the heater unit 300 via a bonding layer 420.

[0023] 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 equipment, 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. The coolant is supplied to and discharged from the coolant flow path 250 through openings 251 and 252 (not shown in FIG. 1 , see FIG. 8 ) formed in a surface 220 of the base plate 200 opposite the surface 210.

[0024] 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.

[0025] The heater unit 300 generates heat upon receiving an external power supply 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 heat generation amount of each heat generating part 331, etc. can be individually adjusted. By individually adjusting the heat generation amount of each part, it is possible to make the in-plane temperature distribution of the substrate W during processing more uniform.

[0026] The heater unit 300 is sandwiched between the dielectric substrate 100 and the base plate 200 and bonded to each. 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 are disposed inside each of the bonding layers to increase thermal conductivity. For example, particles containing alumina as a main component can be used as the filler.

[0027] The specific configuration of the heater unit 300 will be described. FIG. 2 shows the configuration of the heater unit 300 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 terminal 390. Note that in this embodiment, the sub-heater layer 330, the main heater layer 350, and the bypass layer 370 are arranged in this order from top to bottom in FIG. 2, but the arrangement order of these layers may be different from that of this embodiment.

[0028] 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 the "support plate 310A" below. The support plate 310 provided at the lower end in FIG. 2 is also referred to as the "support plate 310B" below. The support plate 310A is a portion that is bonded to the dielectric substrate 100 via a bonding layer 410, and the support plate 310B is a portion that is bonded to the base plate 200 via a bonding layer 420.

[0029] The pair of support plates 310A, 310B are members for reinforcing the entire heater unit 300 by sandwiching the entire sub-heater layer 330, main heater layer 350, bypass layer 370, etc. between them. In this embodiment, both support plates 310A, 310B are made of metal, but they may be made of other materials (e.g., insulating materials). Note that each of the members constituting the heater unit 300, such as the support plate 310, has a plurality of through-holes such as gas holes and lift pin holes, but these are not shown in FIG. 2.

[0030] The insulating layer 320 is provided between the support plate 310A and the sub-heater layer 330 to electrically insulate them from each other. The insulating layer 320 also serves to physically bond them to each other. In this embodiment, the insulating layer 320 is a polyimide film, but it may contain components other than polyimide or may be made of a material other than polyimide. If the support plate 310A is made of an insulating material, the insulating layer 320 may be omitted.

[0031] The sub-heater layer 330 generates heat when power is supplied from an external source. While the sub-heater layer 330 is depicted as a single disk in FIG. 2 , in reality, the sub-heater layer 330 is divided into multiple regions that do not overlap each other when viewed from above, allowing each region to generate heat independently. The specific configuration of the sub-heater layer 330 will be described later.

[0032] The insulating layer 340 is provided between the sub-heater layer 330 and the main heater layer 350 to electrically insulate them from each other. The insulating layer 340 also serves to physically bond them to each other. 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.

[0033] The main heater layer 350, like the sub-heater layer 330 described above, generates heat when power is supplied from an external source. While the main heater layer 350 is depicted as a single disk in Fig. 2, in reality, the main heater layer 350 is divided into multiple regions that do not overlap each other when viewed from above, allowing each region to generate heat independently. The specific configuration of the main heater layer 350 will be described later.

[0034] The main heater layer 350 has a larger heat generation amount per unit area than the sub-heater layer 330 described above. The main heater layer 350 is intended to raise 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 more uniform. In this manner, in this embodiment, two heater layers are provided separately, each with its own role. Alternatively, for example, only the sub-heater layer 330 may be provided, and the main heater layer 350 may not be provided.

[0035] The insulating layer 360 is provided between the main heater layer 350 and the bypass layer 370 to electrically insulate them from each other. The insulating layer 360 also serves to physically bond them to each other. 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.

[0036] The bypass layer 370 is a layer for electrically connecting a power supply terminal 390 (described later) to the sub-heater layer 330 and the main heater layer 350. In FIG. 2 , the bypass layer 370 is schematically depicted as a single disk, but in reality, the bypass layer 370 is divided into multiple pieces. By providing the bypass layer 370 in the middle of the electrical path connected to the sub-heater layer 330, etc., it becomes possible to adjust the position of the power supply terminal 390, etc. A portion of each of the divided bypass layers 370 is electrically connected to the sub-heater layer 330 or the main heater layer 350.

[0037] The insulating layer 380 is provided between the bypass layer 370 and the support plate 310B to electrically insulate them from each other. The insulating layer 380 also serves to physically bond them to each other. In this embodiment, the insulating layer 380 is a polyimide film, but it may contain components other than polyimide or may be made of a material other than polyimide. If the support plate 310B is made of an insulating material, the insulating layer 380 may be omitted.

[0038] 2 are laminated together, the entire assembly is pressurized and heated, thereby bonding the entire assembly together via the insulating layer 320, which is a polyimide film, and forming an integrated unit.

[0039] The power supply terminal 390 is a part that receives, from the outside, the power required to generate heat in the sub-heater layer 330 and the like. In this embodiment, the power supply terminal 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 terminals 390 are provided, corresponding 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 the through holes.

[0040] The structure of the sub-heater layer 330 will now be described. As previously mentioned, the sub-heater layer 330 is divided into multiple regions, and each region can be individually heated. Figure 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 40 regions HA.

[0041] The sub-heater layer 330 is configured as linear heat generating portions 331, which are individually routed in each area HA. ​​That is, in this embodiment, a total of 40 heat generating portions 331 are provided.

[0042] 4 shows an example of a heat generating portion 331 routed in one area HA. ​​In each area HA, one linear heat generating portion 331 is routed along a path that passes uniformly throughout almost the entire area. The heat generating portion 331 generates heat when power is supplied from an external source.

[0043] Circular pad portions 332, 333 are formed on both ends of the heat generating portion 331. The heat generating portion 331 and the pad portions 332, 333 are 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 40 areas HA in total.

[0044] 4 is a schematic view of the heat generating portion 331 and differs from the actual shape. The same applies to the positions of the pad portions 332 and 333.

[0045] 3, the region located at the outermost position is also referred to as the "first region HA1." Also, the region located at a position more inward than the first region HA1 is also referred to as the "second region HA2." In this embodiment, the second region HA2 is the region HA located adjacent to the first region HA1 in the radial direction.

[0046] In this embodiment, a plurality of first regions HA1 are provided, and these are arranged side by side in the circumferential direction. The shapes of the respective first regions HA1 are identical to each other. In this embodiment, all of the plurality of regions HA arranged at the outermost positions have the same shape as each other. Alternatively, among the plurality of first regions HA1 arranged at the outermost positions, a first region HA1 having a shape different from the others may be provided.

[0047] Similarly, in this embodiment, a plurality of second regions HA2 are provided, and these are arranged side by side in the circumferential direction. The shapes of the respective second regions HA2 are identical to each other. In this embodiment, all of the plurality of regions HA arranged at a position immediately inside the first region HA1 are second regions HA2 of the same shape. Alternatively, among the plurality of second regions HA2 arranged at a position immediately inside the first region HA1, a second region HA2 having a different shape from the others may be provided.

[0048] In FIG. 3, the dimension of the first region HA1 along the radial direction is designated by the symbol "L11." Furthermore, the dimension of the second region HA2 along the radial direction is designated by the symbol "L21." Hereinafter, these dimensions will also be referred to as "dimension L11" and "dimension L21." In this embodiment, dimension L11 is smaller than dimension L21. As a result, the area of ​​each first region HA1 is smaller than the area of ​​each second region HA2.

[0049] The radial dimension L11 of the first region HA1 is smaller than the radial dimension of any of the other regions HA, i.e., when comparing the radial dimensions of the respective regions HA, the dimension is smallest in the outermost first region HA1.

[0050] 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 independently. 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 five regions HB.

[0051] The main heater layer 350 is configured as linear heat generating portions 351, which are individually routed in each region HB. That is, in this embodiment, a total of five heat generating portions 351 are provided.

[0052] 6 shows an example of a heat generating portion 351 routed in one area HB. In each area HB, one linear heat generating portion 351 is routed along a path that passes uniformly through almost the entire area. The heat generating portion 351 is a portion that generates heat by receiving power from an external source.

[0053] Circular pad portions 352, 353 are formed on both ends of the heat generating portion 351. The heat generating portion 351 and the pad portions 352, 353 are 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 five regions HB.

[0054] 6 is a schematic view of the heat generating portion 351 and differs from the actual shape. The same applies to the positions of the pad portions 352 and 353.

[0055] The boundaries between the regions HB depicted by dotted lines in Fig. 5 completely overlap with the circumferentially extending (i.e., circular) boundaries between the regions HA depicted by dotted lines in Fig. 3. Therefore, among the multiple regions HB, the region HB designated by the symbol "HB1" in Fig. 5 completely overlaps with the entirety of the multiple first regions HA1 in top view. Similarly, among the multiple regions HB, the region HB designated by the symbol "HB2" in Fig. 5 completely overlaps with the entirety of the multiple second regions HA2 in top view.

[0056] 7 is a schematic perspective view showing 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 will also be referred to as "region HA11" below. The other region HA will also be referred to as "region HA12" below. Note that the shapes of the heat generating portion 331 and other components shown in FIG. 7 are schematic and differ from the actual shapes.

[0057] As described above, the bypass layer 370 is divided into multiple parts. In FIG. 7, only three of the multiple divided bypass layers 370 are shown. Of the three divided bypass layers 370, the one marked with the reference numeral "371" in FIG. 7 is arranged in a position overlapping only one area HA in top view. In other words, each of the bypass layers 370 is individually arranged in a position directly below each area HA. ​​The portion of the bypass layer 370 arranged in this manner will also be referred to as the "bypass layer 371" below.

[0058] 7 is disposed at a position overlapping both the region HA11 and the region HA12 in top view. The portion of the bypass layer 370 disposed in this manner is hereinafter also referred to as the "bypass layer 372."

[0059] In the sub-heater layer 330 arranged in the region HA11, a pad portion 332 at one end of a heat generating portion 331 is electrically connected to the bypass layer 371 located immediately below it. A pad portion 333 at the other end of the heat generating portion 331 is electrically connected to the bypass layer 372.

[0060] The same applies to the sub-heater layer 330 arranged in region HA12, where a pad portion 332 at one end of the heat generating portion 331 is electrically connected to the bypass layer 371 located immediately below it. A pad portion 333 at the other end of the heat generating portion 331 is electrically connected to the bypass layer 372.

[0061] The electrical connections between the above-described components are realized, for example, by welding the upper and lower layers together. To facilitate understanding of the configuration, in Fig. 7, each weld is schematically depicted as a linear rod-shaped member (the portion designated by the reference numeral 301). In the portions overlapping with each weld in top view, openings are formed in each of the layers (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 are directly connected through these openings.

[0062] The sub-heater layer 330 and the bypass layer 370 may be electrically connected by welding as in this embodiment, but may also be electrically connected by other methods. For example, they may be electrically connected via a conductive member extending vertically. In either configuration, an electrical path indicated by reference numeral 301 in FIG. 7 is formed between the sub-heater layer 330 and the bypass layer 370. This electrical path will hereinafter also be referred to as "electrical path 301."

[0063] One end of a power supply terminal 390 is connected to each bypass layer 371 from below in FIG. 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 connected to the bypass layer 372 from below in FIG. 7. This power supply terminal 390 is grounded. The DC power supply and grounding parts shown in FIG. 7 are part of a temperature adjustment control circuit that is externally connected to the electrostatic chuck 10.

[0064] As described above, one pad portion 332 of each of the sub-heater layers 330 provided for each region HA is connected to an individual DC power supply via the bypass layer 371, and the other pad portion 333 is 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 at each portion.

[0065] It is also possible to supply power to the sub-heater layer 330 directly from the power supply terminal 390 without passing through the bypass layer 370. However, by using a configuration in which power is supplied via the bypass layer 370 as in this embodiment, it is possible to increase the degree of freedom in the arrangement of the power supply terminals 390 and to consolidate the power supply terminals 390 that are grounded into one.

[0066] The supply of power to each main heater layer 350 is also realized by the same configuration as above. The specific configuration is the same as that shown in Fig. 7, so the description and illustration thereof will be omitted.

[0067] 8 is a schematic top view of the configuration of the refrigerant flow path 250 formed inside the base plate 200. Note that in FIG. 8, only the portion of the base plate 200 that overlaps with the heater unit 300 in top view is depicted, and other portions are not depicted.

[0068] As described above, openings 251 and 252 are provided on the surface 220 of the base plate 200. The coolant flow path 250 connects the openings 251 and 252 and is formed along a path that passes through each part of the base plate 200 in a top view. Both openings 251 and 252 are circular in a top view and are formed to extend perpendicularly from the surface 220 toward the coolant flow path 250. The internal spaces of the openings 251 and 252 can also be considered as part of the coolant flow path 250. In this embodiment, a coolant is supplied from the outside to the opening 251. The coolant that passes through the coolant flow path 250 and is used to cool the substrate W is discharged to the outside through the opening 252. As shown in FIG. 8 , the coolant flow path 250 is routed along paths that overlap each other in a top view through all the regions HA, including the first region HA1.

[0069] Incidentally, when a substrate W is being processed in a semiconductor manufacturing apparatus, the temperature of the substrate W is likely to rise particularly at its outer peripheral portion. Furthermore, the variation in the in-plane temperature distribution of the substrate W is also likely to be particularly large at the outer peripheral portion of the substrate W. Therefore, if the area of ​​the first region HA1 at the outermost periphery were to be increased, it would be difficult to precisely adjust the temperature at each location on the substrate W. In other words, it would be difficult to adjust the temperature at each location with high resolution. As a result, it may become impossible to achieve a uniform in-plane temperature distribution of the substrate W.

[0070] Therefore, as described above, in this embodiment, the sub-heater layer 330 is divided so that the area of ​​each first region HA1 is smaller than the area of ​​each second region HA2. Specifically, the radial dimension L11 of the first region HA1 is made smaller than the radial dimension L21 of the second region HA2.

[0071] With this configuration, it is possible to individually adjust the amount of heat generated in each of the subdivided first areas HA1, thereby finely adjusting the temperature in each part of the substrate W. As a result, it is possible to suppress local temperature increases and to make the in-plane temperature distribution of the substrate W uniform.

[0072] It is preferable to arrange the regions HA so that the radial dimension L11 of the first region HA1 is equal to or less than half the radial dimension L21 of the second region HA2. By adopting such a configuration, when precise temperature adjustment is performed on the outer peripheral portion of the substrate W, the range affected by this (radial range) can be kept to the minimum necessary.

[0073] In this embodiment, a plurality of first regions HA1 having the same shape are arranged in a circumferential direction, and a plurality of second regions HA2 having the same shape are arranged in a circumferential direction on the inner side of the first regions HA1. By making the shapes of the regions HA arranged in the circumferential direction the same, it becomes possible to easily and appropriately adjust the in-plane temperature distribution of the substrate W.

[0074] To achieve the above-described effect, it is sufficient to have at least two first regions HA1 aligned in the circumferential direction and having the same shape, although it is preferable to have as many first regions HA1 with the same shape as possible.

[0075] In this embodiment, the coolant flow paths 250 are routed along paths that overlap in top view in all areas HA, including the first area HA1. By providing both the subdivided heat generating portion 331 and the coolant flow paths 250 at a position directly below the outermost periphery of the substrate W, where variations in the in-plane temperature distribution are likely to occur, it becomes possible to perform even more precise temperature adjustment.

[0076] At a position more inward than the first region HA1, there may be a region HA that does not overlap with the refrigerant flow path 250 in a top view. In this case, too, it is preferable that the refrigerant flow path 250 be routed along a path that overlaps with at least all of the first region HA1 at the outermost periphery in a top view.

[0077] The above has described a configuration in which a heater for heating the dielectric substrate 100 is provided outside the dielectric substrate 100 in a unitized state as the 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.

[0078] That is, the sub-heater layer 330, the main heater layer 350, and the bypass layer 370 similar to those of this embodiment may each be embedded inside the dielectric substrate 100, similar to the attraction electrode 130. In this case, the connection between the sub-heater layer 330 and the bypass layer 370 may be made, for example, through holes (via holes) filled with a conductor, rather than by welding. Even in this embodiment, the same effects as those of this embodiment can be achieved.

[0079] The heater unit 300 may have the sub-heater layer 330 as in this embodiment, but may not have the main heater layer 350 .

[0080] A second embodiment will be described below. Differences from the first embodiment will be mainly described below, and descriptions of commonalities with the first embodiment will be omitted as appropriate.

[0081] This embodiment differs from the first embodiment in the way the regions are divided in the sub-heater layer 330. In Fig. 9, the arrangement of the sub-heater layer 330 of this embodiment, i.e., the shape of each region HA, is depicted in the same manner as in Fig. 3.

[0082] In FIG. 9, the dimension of the first region HA1 along the circumferential direction is designated by the symbol "L12." Furthermore, the dimension of the second region HA2 along the circumferential direction is designated by the symbol "L22." Hereinafter, these dimensions will also be referred to as "dimension L12" and "dimension L22." In this embodiment, dimension L12 is smaller than dimension L22. As a result, the area of ​​each first region HA1 is smaller than the area of ​​each second region HA2.

[0083] In this manner, in the present embodiment, the area of ​​each first region HA1 is made smaller than the area of ​​each second region HA2 by reducing the circumferential dimension L12 of the first region HA1 rather than reducing the radial dimension L11 of the first region HA1. Even in this aspect, the same effects as those described in the first embodiment can be achieved.

[0084] A third embodiment will be described below. Differences from the first embodiment will be mainly described below, and descriptions of commonalities with the first embodiment will be omitted as appropriate.

[0085] This embodiment also differs from the first embodiment in the way the regions are divided in the sub-heater layer 330. In Fig. 10, the arrangement of the sub-heater layer 330 of this embodiment, i.e., the shape of each region HA, is depicted in the same manner as in Figs. 3 and 9.

[0086] In this embodiment, as in the first embodiment, the radial dimension L11 of the first region HA1 is smaller than the radial dimensions of any of the other regions HA. In other words, when comparing the radial dimensions of each region HA, the dimension is smallest in the outermost first region HA1.

[0087] In this embodiment, the dimension L11 is smaller than the dimension L21, and the dimension L12 is smaller than the dimension L22. As a result, the area per first region HA1 is smaller than the area per second region HA2.

[0088] In this manner, in the present embodiment, by reducing both the radial dimension L11 of the first region HA1 and the circumferential dimension L12 of the first region HA1, the area per one first region HA1 is made smaller than the area per one second region HA2. Even in this aspect, the same effects as those described in the first embodiment can be achieved.

[0089] Even in a configuration such as this embodiment, it is preferable to arrange each region HA so that the radial dimension L11 of the first region HA1 is less than half the radial dimension L21 of the second region HA2.

[0090] A fourth embodiment will be described below. Differences from the first embodiment will be mainly described below, and descriptions of commonalities with the first embodiment will be omitted as appropriate.

[0091] This embodiment also differs from the first embodiment in the way the regions are divided in the sub-heater layer 330. In Fig. 11, the arrangement of the sub-heater layer 330 of this embodiment, i.e., the shape of each region HA, is depicted in the same manner as in Fig. 3 and the like.

[0092] In this embodiment, as in the first embodiment, the radial dimension L11 of the first region HA1 is smaller than the radial dimensions of any of the other regions HA. In other words, when comparing the radial dimensions of each region HA, the dimension is smallest in the outermost first region HA1.

[0093] In this embodiment, the second region HA2 is not adjacent to the first region HA1 in the radial direction. In this embodiment, another region HA is interposed between the second region HA2 and the first region HA1. The shape of each region HA between the second region HA2 and the first region HA1 is generally the same as the shape of the first region HA1.

[0094] In this embodiment, as in the third embodiment (FIG. 10), the dimension L11 is smaller than the dimension L21, and the dimension L12 is smaller than the dimension L22. As a result, the area per first region HA1 is smaller than the area per second region HA2. This configuration also achieves the same effects as those described in the first embodiment.

[0095] Even in a configuration such as this embodiment, it is preferable to arrange each region HA so that the radial dimension L11 of the first region HA1 is less than half the radial dimension L21 of the second region HA2.

[0096] A fifth embodiment will be described below. Differences from the first embodiment will be mainly described below, and descriptions of commonalities with the first embodiment will be omitted as appropriate.

[0097] This embodiment differs from the first embodiment in the configuration of the main heater layer 350. Specifically, the line width of the heat generating portion 351 provided on the main heater layer 350 differs from that of the first embodiment.

[0098] The main heater layer 350 of this embodiment is divided into multiple regions HB, as in the first embodiment, and each region HB can generate heat independently. The shape of each region HB when viewed from above is the same as that shown in FIG. 5. Of the multiple regions HB, the region HB located at the outermost position will be referred to as the "first region HB1" below. Furthermore, the region HB located more inward than the first region HB1 will be referred to as the "second region HB2" below.

[0099] The first region HB1 refers to the region HB designated by the symbol "HB1" in Fig. 5, and the second region HB2 refers to, for example, the region HB designated by the symbol "HB2" in Fig. 5. In a top view, the first region HB1 and the second region HB2 are both annular regions, and their centers coincide with each other.

[0100] 12 shows examples of the heat generating portion 351 routed in the first region HB1 and the heat generating portion 351 routed in the second region HB2. The dimension L11 shown in FIG. 12 is the dimension of the first region HB1 along the radial direction. The dimension L21 shown in the same figure is the dimension of the second region HB2 along the radial direction. The dimension L11 of the first region HB1 is smaller than the dimension L21 of the second region HB2. As a result, the area of ​​the first region HB1 is smaller than the area of ​​the second region HB2.

[0101] Alternatively, the dimension L11 may be smaller than the dimension L21, and the area of ​​the first region HB1 may be equal to or larger than the area of ​​the second region HB2.

[0102] As described above, when a substrate W is being processed in a semiconductor manufacturing apparatus, the temperature of the substrate W is particularly likely to rise in its outer peripheral portion. Therefore, in this embodiment, by arranging the first region HB1 with a narrow width (i.e., dimension L11) directly below the portion where the temperature is likely to rise, it is possible to appropriately adjust the temperature of that portion. In other words, by separately adjusting the temperature of the outer peripheral portion of the substrate W where the temperature is likely to rise from the other portions, it is possible to make the overall temperature distribution closer to uniform.

[0103] In this embodiment, the first region HB1 is a single annular region. In the annular first region HB1, a single linear heat generating portion 351 is routed along a path that passes uniformly through almost the entire area of ​​the first region HB1. Furthermore, most of the heat generating portion 351 is formed to extend annularly in the circumferential direction.

[0104] Similarly, the second region HB2 in this embodiment is a single annular region. The center of the first region HB1 and the center of the second region HB2 coincide with each other in a top view. In the annular second region HB2, a single linear heat generating portion 351 is routed along a path that passes evenly through almost the entire area. Furthermore, most of the heat generating portion 351 is formed to extend annularly in the circumferential direction.

[0105] 12, the line width of the heat generating portion 351 routed in the first region HB1 is smaller than the line width of the heat generating portion 351 routed in the inner second region HB2. The "line width" here refers to the dimension of the heat generating portion 351 in the direction perpendicular to the direction in which the heat generating portion 351 extends.

[0106] To explain the reason for this configuration, we will first describe the configuration of a comparative example. In the comparative example shown in Figure 13, the shapes of the first region HB1 and the second region HB2 are the same as those of this embodiment. However, in this comparative example, the line width of the heat generating portion 351 routed in the first region HB1 is equal to the line width of the heat generating portion 351 routed in the second region HB2 inside it. In other words, the line width of the heat generating portion 351 routed in the first region HB1 is larger than that of the present embodiment shown in Figure 12.

[0107] With this configuration, in the second region HB2, which is relatively wide, four heat generating parts 351 can be routed along the radial direction, whereas in the first region HB1, which is relatively narrow, only one or two heat generating parts 351 can be routed along the radial direction.

[0108] In this way, if the line width of the heat generating portion 351 is not adjusted for each region HB, the degree of freedom in routing the heat generating portion 351 in the first region HB1 will be reduced. Since it becomes difficult to route the heat generating portion 351 along a path that passes evenly throughout the entire first region HB1, the temperature difference between the portion of the first region HB1 where the heat generating portion 351 passes and the portion where it does not pass will likely become large.

[0109] Therefore, in this embodiment, the line width of the heat generating portion 351 routed in the first region HB1 is made smaller than the line width of the heat generating portion 351 routed in the second region HB2, thereby increasing the degree of freedom in routing the heat generating portion 351 in the first region HB1. In the example of Fig. 12, it is possible to route the same number (four) of heat generating portions 351 in the radial direction in both the first region HB1 and the second region HB2.

[0110] By reducing the line width of the heat generating portion 351, it is possible to route the heat generating portion 351 along a path that passes evenly throughout the first region HB1, thereby reducing the temperature difference between each portion of the first region HB1 compared to the comparative example in FIG.

[0111] It is also possible to reduce the line width of the heat generating portion 351 in the second region HB2 to approximately the same as the line width of the heat generating portion 351 in the first region HB1. However, reducing the line width of the heat generating portion 351 in all regions HB may cause problems such as making it difficult to form the heat generating portion 351 during manufacturing. Therefore, it is preferable to make the line widths of the heat generating portion 351 different between the first region HB1 and the second region HB2, as in this embodiment.

[0112] Furthermore, if the line width of the heat generating portion 351 becomes locally narrow due to a manufacturing defect or the like, the amount of heat generated in that portion may become locally large. If such a phenomenon occurs in the heat generating portion 351 having only one wire routed therethrough as in the example of Figure 13, it becomes difficult to uniformize the temperature within the surface of the substrate W.

[0113] On the other hand, in a configuration in which a plurality of heat generating portions 351 are arranged parallel to one another in the first region HB1 as in this embodiment ( FIG. 12 ), even if the line width of some of the heat generating portions 351 is locally narrowed, other heat generating portions 351 are routed in the vicinity thereof. For this reason, the influence of an abnormality in the line width of the heat generating portion 351 on the temperature distribution of the substrate W is kept small compared to a case in which only one heat generating portion 351 is routed.

[0114] In order to obtain such an effect, it is preferable to arrange the heat generating portions 351 in the first region HB1 at a higher density than the heat generating portions 351 in the second region HB2, as in this embodiment. The "arrangement density" here refers to the number of heat generating portions 351 arranged per unit length in a direction perpendicular to the direction in which the heat generating portions 351 extend (the radial direction in the example of FIG. 12).

[0115] Of the multiple regions HB, the line width and arrangement density of the heat generating portions 351 in the other regions HB not shown in FIG. 12 are the same as the line width and arrangement density of the heat generating portions 351 in the second region HB2.

[0116] The second region HB2 may be a region HB adjacent to the first region HB1 as in this embodiment, or may be a region HB that is not adjacent to the first region HB1.

[0117] The configuration of the sub-heater layer 330 in this embodiment is the same as that in the first embodiment, but may be different from that in the first embodiment. Also, the heater unit 300 may be configured to include the main heater layer 350 as in this embodiment, but not include the sub-heater layer 330.

[0118] The configuration in which the line width of the heat generating portion in the outer peripheral region is smaller than the line width of the heat generating portion in the inner peripheral region may be adopted in the other embodiments described so far. For example, in the configuration of the first embodiment (FIG. 3, etc.), the line width of the heat generating portion 331 routed in the first region HA1 may be smaller than the line width of the heat generating portion 331 routed in the second region HA2.

[0119] The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Design modifications to these specific examples made by a person skilled in the art as appropriate are also included within the scope of the present disclosure as long as they comprise the features of the present disclosure. The elements of the above-described specific examples, as well as their arrangement, conditions, shape, etc., are not limited to those exemplified and can be modified as appropriate. The elements of the above-described specific examples can be combined in various ways as appropriate, as long as no technical contradictions arise.

[0120] 10: Electrostatic chuck 100: Dielectric substrate 110: Surface 200: Base plate 250: Coolant flow path 300: Heater unit 331, 351: Heat generating portion HA: 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 attracted is placed; and a heater for heating the dielectric substrate, wherein, when viewed from a direction perpendicular to the mounting surface, the heater has a heat generating portion which is a conductor that is 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 including a first region located at the outermost position and a second region located at a position more inward than the first region, and wherein the area of ​​the first region is smaller than the area of ​​the second region.

2. The electrostatic chuck according to claim 1, characterized in that a plurality of the first regions having the same shape are arranged in a circumferential direction, and a plurality of the second regions having the same shape are arranged in a circumferential direction.

3. An electrostatic chuck as set forth in claim 2, wherein the dimension of said first region along the circumferential direction is smaller than the dimension of said second region along the circumferential direction.

4. The electrostatic chuck of claim 2, wherein the first region has a smaller radial dimension than the second region.

5. An electrostatic chuck according to claim 4, wherein the dimension of said first region along the radial direction is equal to or less than half the dimension of said second region along the radial direction.

6. An electrostatic chuck as described in claim 2, further comprising a base plate as a member for supporting the dielectric substrate, the base plate having a coolant flow path formed therein through which a coolant passes, wherein, when viewed from a direction perpendicular to the mounting surface, the coolant flow path is routed along a path that overlaps all of the first regions.

7. The electrostatic chuck of claim 1, wherein the first region has a smaller radial dimension than the second region.

8. An electrostatic chuck as set forth in claim 7, wherein the line width of the heat generating portion routed in the first region is smaller than the line width of the heat generating portion routed in the second region.

9. The electrostatic chuck according to claim 8, wherein the first region and the second region are both annular regions, and the centers of the first and second regions are aligned with each other.

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