electrostatic chuck

Abstract

To provide an electrostatic chuck capable of performing precise temperature adjustment by a heater.SOLUTION: The electrostatic chuck 10 includes a dielectric substrate 100 and a heater unit 300 for heating the dielectric substrate 100. In a top view, the heater unit 300 includes a heating portion 331 which is a conductor wired 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 closest to the outer periphery and a second region HA2 disposed at a position closer to the inner periphery than the first region HA1. The line width of the heating portion 331 routed in the first area HA1 is smaller than the line width of the heating portion 331 routed in the second area HA2.SELECTED DRAWING: Figure 4

Description

Technical Field

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

Background Art

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

[0003] During processing of the substrate, it is required to make the in-plane temperature distribution of the substrate as uniform as possible. In recent years, electrostatic chucks equipped with heaters have been developed and already put into practical use in order to make it possible to adjust the in-plane temperature distribution of the substrate with high accuracy. As described in, for example, the following Patent Document 1, the heater may be provided outside the dielectric substrate in a unitized state, or may be provided inside the dielectric substrate. In any configuration, the heater has a heat generating portion which is a conductor routed in a linear shape. The heat generating portion is not provided as only one in the entire heater, but is often routed individually in each of a plurality of regions.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of Invention

Problems to be Solved by the Invention

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

[0006] Incidentally, due to manufacturing defects in the heater, for example, the line width of the heating element may become locally narrower or wider in some areas. If such abnormalities in line width occur directly beneath the outer edge of the circuit board, it may become difficult to precisely control the temperature using the heater.

[0007] This invention has been made in view of these problems, and its objective is to provide an electrostatic chuck capable of precise temperature control using a heater. [Means for solving the problem]

[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 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.

[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. [Effects of the Invention]

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

[0012] [Figure 1] This is a schematic cross-sectional view showing the configuration of the electrostatic chuck according to the first embodiment. [Figure 2] Figure 1 is a schematic exploded view showing the configuration of the heater unit. [Figure 3] This figure shows an example of the arrangement of the sub-heater layer in the heater unit shown in Figure 1. [Figure 4] This figure shows the configuration of the subheater layer in the heater unit shown in Figure 1. [Figure 5] This figure shows an example of the arrangement of the main heater layer in the heater unit shown in Figure 1. [Figure 6] This figure shows the configuration of the main heater layer in the heater unit shown in Figure 1. [Figure 7] This is a diagram to explain the role of the bypass layer, etc. [Figure 8] This figure shows an example of the arrangement of the main heater layer in a heater unit according to the second embodiment. [Figure 9] This figure shows the configuration of the main heater layer in the heater unit according to the second embodiment. [Figure 10] This figure shows the configuration of the main heater layer in the heater unit of the comparative example. [Modes for carrying out the invention]

[0013] Hereinafter, the present embodiment will be described with reference to the accompanying drawings. To facilitate understanding of the description, identical reference numerals are assigned to identical constituent elements in each drawing as far as possible, and duplicate descriptions are omitted.

[0014] A first embodiment will be described. An electrostatic chuck 10 according to the present embodiment adsorbs and holds a substrate W, which is a processing target, by electrostatic force inside a semiconductor manufacturing apparatus (not shown) such as an etching apparatus. The substrate W, which is the object to be adsorbed, is, for example, a silicon wafer. The electrostatic chuck 10 may be used in apparatuses other than semiconductor manufacturing apparatuses.

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

[0016] The dielectric substrate 100 is a substantially disk-shaped member made of a ceramic sintered body. The dielectric substrate 100 contains, for example, high-purity aluminum oxide (Al₂O₃), but may contain other materials. The purity and type of ceramics, additives, and the like in the dielectric substrate 100 can be appropriately set in consideration of plasma resistance and the like required for the dielectric substrate 100 in a semiconductor manufacturing apparatus.

[0017] An upper surface 110 of the dielectric substrate 100 in FIG. 1 serves as a "mounting surface" on which the substrate W is mounted. In addition, a lower surface 120 of the dielectric substrate 100 in FIG. 1 serves as a "bonded surface" that is bonded to the heater unit 300 via a bonding layer 410. A viewpoint when the electrostatic chuck 10 is viewed from the surface 110 side along the direction perpendicular to the surface 110 is hereinafter also referred to as "top view".

[0018] An attraction electrode 130 is embedded inside the dielectric substrate 100. The attraction electrode 130 is a thin flat plate-shaped layer formed of a metal material such as tungsten, and is arranged to be parallel to the surface 110. As the material of the attraction electrode 130, in addition to tungsten, molybdenum, platinum, palladium or the like may be used. When a voltage is applied to the attraction 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, whereby the substrate W is attracted and held. Only one attraction electrode 130 may be provided as a so-called "unipolar" electrode as in the present embodiment, or two attraction electrodes 130 may be provided as so-called "bipolar" electrodes.

[0019] As shown in FIG. 1, a space SP is formed between the dielectric substrate 100 and the substrate W. When processing such as etching is performed in a semiconductor manufacturing apparatus, helium gas for temperature adjustment is supplied from the outside to the space SP through gas holes (not shown). By interposing the helium gas between the dielectric substrate 100 and the substrate W, the thermal resistance between the two is adjusted, whereby the temperature of the substrate W is maintained at an appropriate temperature. The temperature adjustment gas supplied to the space SP may be a gas of a type different from helium.

[0020] A seal ring 111 and dots 112 are provided on the surface 110 which is a mounting surface, and the above space SP is formed around these components.

[0021] The seal ring 111 is a wall that partitions the space SP at the position of the outermost periphery. The upper end of the seal ring 111 forms a part of the surface 110 and abuts against the substrate W. A plurality of seal rings 111 may be provided so as to divide the space SP. With such a 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 nearly uniform.

[0022] In Figure 1, the portion labeled "116" is the bottom surface of the 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 the surface 110 down to the position of the 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 roughly 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 equipment, 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 serves to electrically insulate the two. The insulating layer 320 also plays a role in physically joining 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 disk, 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 serves to electrically insulate them from each other. The insulating layer 340 also plays a role in physically joining the two layers. 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 serves to electrically insulate the two. The insulating layer 380 also plays a role in physically joining 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 bonded 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 subheater layer 330 will now be described. As mentioned earlier, the subheater layer 330 is divided into multiple regions, and each region can be heated individually. Figure 3 shows an example of how the subheater layer 330 is divided, viewed from above. In this example, the subheater layer 330 is divided into a total of 24 regions HA.

[0043] As shown in Figure 4, the subheater layer 330 is configured as linear heat-generating units 331, which are individually routed within each region HA. In other words, a total of 24 heat-generating units 331 are provided in this embodiment. Each heat-generating unit 331 is a part that generates heat by receiving power from an external source.

[0044] In Figure 3, the region located at the outermost periphery of the multiple regions HA is hereinafter referred to as "first region HA1". The region located at an inner periphery of the first region HA1 is hereinafter referred to as "second region HA2". In this embodiment, the second region HA2 is a region HA located adjacent to the first region HA1 in the radial direction. The first region HA1 and the second region HA2 do not necessarily have to be adjacent to each other in the radial direction.

[0045] In this embodiment, multiple first regions HA1 are provided, arranged in a circumferential direction. Each first region HA1 has the same shape. In this embodiment, all of the multiple regions HA located at the outermost position are first regions HA1 with the same shape. Alternatively, among the multiple first regions HA1 located at the outermost position, there may be first regions HA1 with a different shape from the others.

[0046] Similarly, in this embodiment, multiple second regions HA2 are provided, and these are arranged in a circumferential direction. The shape of each second region HA2 is identical to that of the others. In this embodiment, all of the multiple regions HA located one inward from the first region HA1 are second regions HA2 of the same shape. Alternatively, among the multiple second regions HA2 located one inward from the first region HA1, there may be second regions HA2 with different shapes from the others.

[0047] Figure 4 shows an example of a pair of first regions HA1 and second regions HA2, and the heat-generating elements 331 routed within each region HA. In each region HA, a single linear heat-generating element 331 is routed along a path that passes through almost the entire area equally.

[0048] Circular pad portions 332 and 333 are formed at each end of the heating element 331. The heating element 331 and the pad portions 332 and 333 are formed, for example, by etching a thin metal foil, and the whole structure functions as a single subheater layer 330. In other words, one subheater layer 330 is provided for each of the 24 regions HA.

[0049] Note that the shape of the heating element 331 shown in Figure 4 is schematic and differs from the actual shape. The same applies to the positions of the pads 332 and 333.

[0050] In Figure 4, the symbol "D11" indicates the dimension of the first region HA1 along the radial direction. Similarly, the symbol "D12" in the same figure indicates the dimension of the second region HA2 along the radial direction. Hereafter, these will also be referred to as "dimension D11" and "dimension D12," respectively. In this embodiment, dimensions D11 and D12 are equal to each other.

[0051] As shown in Figure 4, the line width of the heat-generating element 331 routed in the first region HA1 is smaller than the line width of the heat-generating element 331 routed in the second region HA2 inside it. Here, "line width" refers to the dimensions of the heat-generating element 331 in a direction perpendicular to the direction in which the heat-generating element 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 heat-generating elements 331 are arranged within the range of dimension D11. In the second region HA2, five heat-generating elements 331 are arranged within the range of dimension D12. Dimensions D11 and D12 are equal to each other. Therefore, the arrangement density of heat-generating elements 331 in the first region HA1 is higher than the arrangement density of heat-generating elements 331 in the second region HA2. Here, "arrangement density" refers to the number of heat-generating elements 331 arranged per unit length in a direction perpendicular to the direction in which the heat-generating elements 331 extend (the radial direction in the example of Figure 4). Among the multiple regions HA, the line width and arrangement density of heat-generating 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 heat-generating 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 each region can be heated individually. Figure 5 shows an example of how the main heater layer 350 is divided, viewed from above. 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 periphery of the multiple regions HB is hereinafter referred to as "first region HB1". The region located at an inner periphery of 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 HA1 and the second region HA2 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 perfectly 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 perfectly overlaps with the entirety of multiple first regions HA1. Similarly, in a top view, the second region HB2 perfectly 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 elements 351 routed within each region HB. In each region HB, a single linear heat-generating element 351 is routed along a path that passes through almost the entire area equally. Furthermore, most of the heat-generating element 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 dimension labeled "D21" represents the dimension of the first region HB1 along the radial direction. Similarly, the dimension labeled "D22" represents 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 heat-generating element 351 routed in the first region HB1 is smaller than the line width of the heat-generating element 351 routed in the second region HB2 inside it. Here, "line width" refers to the dimensions of the heat-generating element 351 in a direction perpendicular to the direction in which the heat-generating element 351 extends.

[0064] In each region HB, there are multiple portions of the heat-generating 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 heat-generating 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 heat-generating 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 the 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 bypass layers 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 labeled 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 achieved 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, temperature control by the heater unit 300 needs to be particularly precise directly beneath the outer peripheral portion of substrate W. In other words, the amount of heat generated in each part of the first region HA1 and the first region HB1 needs to be controlled with particular precision.

[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 edge 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] One possible measure to suppress the effects of abnormal line width is to uniformly reduce the line width of all heating elements 331 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, due to the structure of the electrostatic chuck 10 or the like, there are areas on the substrate W where the temperature tends to be locally lower, the line width of the heat-generating part 331, etc., that overlaps with such areas when viewed from above may be intentionally made narrower. 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 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 locally widening the line width 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 innermost 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 region, the 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 closer to uniform.

[0095] It is preferable to arrange each region 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 (radially oriented area) can be kept to the minimum necessary.

[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 element 351 routed in the first region HB1 is smaller than the line width of the heat-generating element 351 routed in the second region HB2 inside it.

[0098] In each region HB, there are multiple portions of the heat-generating 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 heat-generating 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 heat-generating 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. This configuration allows for the same effects as those described in the first embodiment.

[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 radially 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 radially.

[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 few or no 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 evenly throughout the entire first region HB1. 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. [Explanation of Symbols]

[0108] 10: Electrostatic Chuck 100: Dielectric substrate 110: Face 300: Heater unit 331,351: Heat-generating part HA,HB:Area HA1,HB1: 1st area HA2,HB2: 2nd area W: Circuit board

Claims

1. A dielectric substrate having a mounting surface on which an object to be adsorbed is placed, The dielectric substrate is heated by a heater, The heater has a main heater layer and a sub-heater layer provided at different height positions, and is bonded from the outside to the surface of the dielectric substrate opposite to the surface described above. When viewed from a direction perpendicular to the mounting surface, Each of the main heater layer and the sub-heater layer is, Each of the multiple regions, separated so as not to overlap, has a heating element which is a conductor routed individually and linearly. The number of regions in the main heater layer is less than the number of regions in the sub-heater layer. The plurality of regions in the main heater layer are, The first circular region is located at the outermost position, It includes a plurality of second regions, which are annular regions positioned on the inner circumference side of the first region, The dimensions of the first region along the radial direction are smaller than the dimensions of any of the second regions along the radial direction. The wire width of the heating element routed in the first region is smaller than the wire width of the heating element routed in any of the second regions. An electrostatic chuck 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 any of the second regions.

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

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