Electrostatic chuck

Abstract

To provide an electrostatic chuck capable of easily adjusting a heat generation performance of a heater in each region.SOLUTION: An electrostatic chuck 10 comprises: a dielectric substrate 100; and a heater unit 300 that heats the dielectric substrate 100. In an upper view, the heater unit 300 contains: a heat generation part 331A that is individually configured into each inner side of a plurality of regions HA that is divided so as to be not overlapped each other; and a heat generation part 331B that is individually configured into the inner side of at least one part of the region HA at a high position that is different from the heat generation part 331A.SELECTED DRAWING: Figure 9

Description

Technical Field

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

Background Art

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

[0003] When processing a substrate in a semiconductor manufacturing apparatus, it is necessary to perform temperature adjustment so that the in-plane temperature distribution of the substrate becomes as uniform as possible. In order to enable temperature adjustment with high accuracy, in recent years, an electrostatic chuck equipped with a heater has also been developed and has already been put into practical use. The heater may be provided inside the dielectric substrate, but may also be provided between the dielectric substrate and the base plate in a unitized state as described in Patent Document 1 below, for example.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The heater has a heat generating portion that is a conductor wound linearly. When power is supplied from the outside and an electric current flows through the heat generating portion, Joule heat is generated in the heat generating portion. In order to be able to individually adjust the temperature of each part of the dielectric substrate, the heat generating portion of the heater is individually wound in each of a plurality of regions.

[0006] It is desirable to individually adjust in advance the heat generation performance (for example, the reciprocal of the electrical resistance value) of the heat generating portion in each region so as to be appropriate according to the position and size of the region. Therefore, for example, it is conceivable to adjust the line width, length, etc. of the heat generating portion for each region. However, such adjustment is often difficult. For example, if the line width of the heat generating portion is made too narrow, the possibility of disconnection increases.

[0007] The present invention has been made in view of such problems, and an object thereof is to provide an electrostatic chuck capable of easily adjusting the heat generation performance of a heater in each region.

Means for Solving the Problems

[0008] In order to solve the above problems, the electrostatic chuck according to the present invention includes a dielectric substrate having a mounting surface on which an object to be adsorbed is mounted, and a heater for heating the dielectric substrate. When viewed from a direction perpendicular to the mounting surface, the heater includes a first heat generating portion individually routed inside each of a plurality of regions separated so as not to overlap each other, and a second heat generating portion individually routed inside at least a part of the regions at a height position different from that of the first heat generating portion.

[0009] In the electrostatic chuck having the above configuration, in each of a plurality of regions separated so as not to overlap each other, the first heat generating portion is individually routed. Thereby, it becomes possible to individually change the heat generation amount of the heater in each region and adjust the in-plane temperature distribution of the substrate during processing.

[0010] In at least a part of the plurality of regions, in addition to the first heat generating portion, the second heat generating portion is also routed. The second heat generating portion is routed in the same region as the first heat generating portion at a height position different from that of the first heat generating portion. Note that the "height position" is the position in the direction perpendicular to the mounting surface.

[0011] For example, when a first heating part and a second heating part in the same region are connected in series with each other, the total electrical resistance of the heating parts increases as compared with the case where the second heating part is absent. Further, when the first heating part and the second heating part in the same region are connected in parallel with each other, the total electrical resistance of the heating parts decreases as compared with the case where the second heating part is absent. In any case, it is possible to appropriately adjust the heat generation performance of the heater in the region without changing the line width of the first heating part or the like.

[0012] Note that the above configuration is merely an example. A configuration may be adopted in which the first heating part and the second heating part in the same region are not connected to each other, and power is supplied to each of them individually from the outside.

Advantages of the Invention

[0013] According to the present invention, it is possible to provide an electrostatic chuck capable of easily adjusting the heat generation performance of the heater in each region.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

[0015] Hereinafter, this embodiment will be described with reference to the accompanying drawings. For ease of understanding the description, the same components in each drawing are denoted by the same reference numerals as much as possible, and redundant descriptions are omitted.

[0016] The electrostatic chuck 10 according to this embodiment adsorbs and holds a substrate W to be processed by electrostatic force inside a semiconductor manufacturing apparatus (not shown) such as an etching apparatus. The substrate W to be adsorbed is, for example, a silicon wafer. The electrostatic chuck 10 may be used in an apparatus other than a semiconductor manufacturing apparatus.

[0017] FIG. 1 shows a configuration of the electrostatic chuck 10 in a state where the substrate W is adsorbed and held as a schematic cross-sectional view. The electrostatic chuck 10 includes a dielectric substrate 100, a base plate 200, and a heater unit 300.

[0018] The dielectric substrate 100 is a substantially disk-shaped member made of a ceramic sintered body. The dielectric substrate 100 includes, for example, high-purity aluminum oxide (Al 2 O 3 ), but may include other materials. The purity, type, additives, etc. of the ceramics in the dielectric substrate 100 can be appropriately set in consideration of the plasma resistance required for the dielectric substrate 100 in a semiconductor manufacturing apparatus.

[0019] Of the dielectric substrate 100, the upper surface 110 in FIG. 1 is the "placement surface" on which the substrate W is placed. Also, the lower surface 120 of the dielectric substrate 100 in FIG. 1 is the "surface to be joined" that is joined to the heater unit 300 via the joining layer 410. Along the direction perpendicular to the surface 110, the viewpoint when viewing the electrostatic chuck 10 from the surface 110 side will also be referred to as the "top view" hereinafter.

[0020] An adsorption electrode 130 is embedded inside the dielectric substrate 100. The adsorption electrode 130 is a thin flat plate-shaped layer formed of a metal material such as tungsten, for example, and is arranged to be parallel to the surface 110. As the material of the adsorption electrode 130, in addition to tungsten, molybdenum, platinum, palladium, etc. may also be used. 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, and thereby the substrate W is adsorbed and held. As the configuration of the above power supply path, various known configurations can be adopted. The adsorption electrode 130 may be provided only one as a so-called "single-pole" electrode as in this embodiment, or may be provided two as a so-called "bipolar" electrode.

[0021] 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 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 interposing helium gas between the dielectric substrate 100 and the substrate W, the thermal resistance between the two is adjusted, and thereby the temperature of the substrate W is maintained at an appropriate temperature. Note that the gas for temperature adjustment supplied to the space SP may be a different type of gas from helium.

[0022] A seal ring 111 and dots 112 are provided on the surface 110 which is the placement surface, and the above space SP is formed around these.

[0023] The seal ring 111 is a wall that partitions the space SP at the outermost peripheral position. The upper end of the seal ring 111 forms part of the surface 110 and abuts against the substrate W. Incidentally, a plurality of seal rings 111 may be provided so as to divide the space SP. With such a configuration, the pressure of the helium gas in each space SP can be individually adjusted, and the surface temperature distribution of the substrate W during processing can be made closer to uniform.

[0024] In FIG. 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 is formed as a result of digging down a part of the surface 110 to the position of the bottom surface 116 together with the dots 112 described below.

[0025] The dots 112 are circular protrusions protruding from the bottom surface 116. A plurality of dots 112 are provided and are arranged substantially evenly and dispersedly on the mounting surface of the dielectric substrate 100. The upper end of each dot 112 forms part of the surface 110 and abuts against the substrate W. By providing a plurality of such dots 112, the deflection of the substrate W is suppressed.

[0026] 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, for example. Among the base plate 200, the upper surface 210 in FIG. 1 is a "surface to be joined" that is joined to the heater unit 300 via the joining layer 420.

[0027] Inside the base plate 200, a refrigerant flow path 250 for flowing refrigerant is formed. When processing such as etching is performed in the semiconductor manufacturing apparatus, refrigerant is supplied from the outside to the refrigerant flow path 250, and thereby the base plate 200 is cooled. The heat generated in the substrate W during processing is transmitted to the refrigerant through 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.

[0028] 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 the insulating film, the dielectric breakdown voltage of the base plate 200 can be increased.

[0029] The heater unit 300 receives power supply from the outside and generates heat to heat the dielectric substrate 100. As will be described later, the heater unit 300 is provided with a plurality of heating parts 331A etc., and it is possible to individually adjust the calorific value in each heating part 331A etc. By individually adjusting the calorific value of each part, the in-plane temperature distribution of the substrate W during processing can be made closer to being uniform.

[0030] The heater unit 300 is sandwiched between the dielectric substrate 100 and the base plate 200 and is joined to each of them. The heater unit 300 and the dielectric substrate 100 are joined via a joining layer 410, and the heater unit 300 and the base plate 200 are joined via a joining layer 420. The joining layers 410, 420 are layers formed, for example, by curing a silicone adhesive. A plurality of particulate fillers for increasing the thermal conductivity are arranged inside each of them. As the filler, for example, particles mainly composed of alumina can be used.

[0031] The specific configuration of the heater unit 300 will be described. In FIG. 2, the configuration of the heater unit 300 is shown as a schematic exploded assembly drawing. As shown in the figure, the heater unit 300 has a support plate 310(310A), an insulating layer 321, a sub-heater layer 330, an insulating layer 323, a main heater layer 350, an insulating layer 324, a bypass layer 370, an insulating layer 325, a support plate 310(310B), and a power supply unit 390. In addition, in the present embodiment, the sub-heater layer 330, the main heater layer 350, and the bypass layer 370 are arranged in this order from above, but the arrangement order of these may be different from that of the present embodiment.

[0032] The support plate 310 is a substantially disk-shaped member, and is provided at each of the upper and lower end portions of the heater unit 300 shown in FIG. 2. The support plate 310 provided at the upper end portion in FIG. 2 is hereinafter also referred to as "support plate 310A". The support plate 310 provided at the lower end portion in FIG. 2 is hereinafter also referred to as "support plate 310B". The support plate 310A is a portion joined to the dielectric substrate 100 via the bonding layer 410, and the support plate 310B is a portion joined to the base plate 200 via the bonding layer 420.

[0033] The pair of support plates 310A and 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. therebetween. In the present embodiment, both the support plates 310A and 310B are formed of metal, but they may be formed of other members (for example, insulating members). Incidentally, a plurality of through holes are formed in each member such as the support plate 310 constituting the heater unit 300 for the purpose of passing lift pins therethrough, etc., but the illustration thereof is omitted in FIG. 2.

[0034] The insulating layer 321 is provided between the support plate 310A and the sub-heater layer 330, and is a layer for electrically insulating the two. Further, the insulating layer 321 also has a role of physically joining the two. The insulating layer 321 is a polyimide film in the present embodiment, but may contain components other than polyimide and may be formed of a material different from polyimide. When the support plate 310A is formed of an insulating material, the insulating layer 321 can be eliminated.

[0035] The sub-heater layer 330 is a part that generates heat upon receiving power supply from the outside. The sub-heater layer 330 has a first sub-heater layer 330A and a second sub-heater layer 330B, and each can generate heat. An insulating layer 322 is disposed between the first sub-heater layer 330A and the second sub-heater layer 330B. The insulating layer 322 is a layer for electrically insulating between the two. Also, the insulating layer 322 also has a role of physically joining between the two. The insulating layer 322 is a polyimide film in this embodiment, but may contain components other than polyimide and may be formed of a material different from polyimide.

[0036] In FIG. 2, the first sub-heater layer 330A is schematically depicted as a single disc, but in reality, the first sub-heater layer 330A is divided into a plurality of regions, and each region can generate heat individually. Similarly, the second sub-heater layer 330B is also divided into a plurality of regions, and each region can generate heat individually. The specific configuration of the sub-heater layer 330 will be described later.

[0037] The insulating layer 323 is provided between the second sub-heater layer 330B and the main heater layer 350, and is a layer for electrically insulating between the two. Also, the insulating layer 323 also has a role of physically joining between the two. The insulating layer 323 is a polyimide film in this embodiment, but may contain components other than polyimide and may be formed of a material different from polyimide.

[0038] The main heater layer 350 is a part that generates heat upon receiving power supply from the outside, similar to the sub-heater layer 330 described above. In FIG. 2, the main heater layer 350 is schematically depicted as a single disc, but in reality, the main heater layer 350 is divided into a plurality of regions, and each region can generate heat individually. The specific configuration of the main heater layer 350 will be described later.

[0039] The main heater layer 350 has a larger calorific value per unit area compared to the sub-heater layer 330 described above. The main heater layer 350 is for raising the temperature of the entire dielectric substrate 100 in a short time. The sub-heater layer 330 is for adjusting the temperature of each part of the dielectric substrate 100 and making the in-plane temperature distribution of the substrate W closer to uniform. Thus, in this embodiment, two types of heater layers corresponding to their respective roles are provided separately.

[0040] The insulating layer 324 is provided between the main heater layer 350 and the bypass layer 370 and is a layer for electrically insulating between the two. Also, the insulating layer 324 also has the role of physically joining between the two. The insulating layer 324 is a polyimide film in this embodiment, but may contain components other than polyimide and may be formed of a material different from polyimide.

[0041] The bypass layer 370 is a layer for electrically connecting the power supply unit 390 described later and the sub-heater layer 330 and the main heater layer 350. In FIG. 2, the bypass layer 370 is schematically drawn as if it were a single disk, but actually, the bypass layer 370 is divided into a plurality. By providing the bypass layer 370 in the middle of the circuit connected to the sub-heater layer 330 or the like, it becomes possible to adjust the position of the power supply unit 390 or the like. Each of the divided bypass layers 370 has a part thereof welded to the sub-heater layer 330 or the main heater layer 350.

[0042] The insulating layer 325 is provided between the bypass layer 370 and the support plate 310B and is a layer for electrically insulating between the two. Also, the insulating layer 325 also has the role of physically joining between the two. The insulating layer 325 is a polyimide film in this embodiment, but may contain components other than polyimide and may be formed of a material different from polyimide. If the support plate 310B is formed of an insulating material, it is also possible to eliminate the insulating layer 325.

[0043] When manufacturing the heater unit 300, while the respective layers shown in FIG. 2 are in a stacked state, the entirety of these is pressurized and heated. As a result, the whole is joined and integrated via the insulating layer 321 and the like which are polyimide films.

[0044] The power supply unit 390 is a portion that receives power from the outside, which is necessary to cause the sub-heater layer 330 and the like to generate heat. In the present embodiment, the power supply unit 390 is formed as an elongated rod-shaped plug, and one end thereof is connected to the bypass layer 370. Since a plurality of power supply units 390 are provided according to the number of bypass layers 370, only two of them are shown in FIG. 2. In the base plate 200, through holes (not shown) are formed at respective positions corresponding to the power supply units 390, and the power supply units 390 are inserted into the through holes.

[0045] The configuration of the first sub-heater layer 330A among the sub-heater layers 330 will be described. As described above, the first sub-heater layer 330A is divided into a plurality of regions, and it is possible to generate heat individually in each region. FIG. 3 shows an example of the way of dividing the first sub-heater layer 330A in a top view. In this example, the sub-heater layer 330 is divided into a total of 32 regions HA. The regions HA are obtained by dividing a circular region substantially equal to the shape of the dielectric substrate 100 into a plurality of regions so as not to overlap each other in a top view.

[0046] The first sub-heater layer 330A is configured as a linear heating portion 331A, and is individually routed inside each region HA. That is, a total of 32 heating portions 331A are provided in the present embodiment.

[0047] FIG. 4 shows an example of the heating portion 331A routed inside one region HA. In each region HA, one linear heating portion 331A is routed along a path that passes through substantially all of the region evenly. The heating portion 331A is a portion that generates heat by receiving power supply from the outside, and corresponds to the "first heating portion" of the present embodiment.

[0048] Circular pad portions 332A and 333A are formed at both ends of the heat generating portion 331A. The heat generating portion 331A and the pad portions 332A and 333A are formed, for example, by etching a thin metal foil, and the whole thereof functions as one first sub-heater layer 330A. In other words, one first sub-heater layer 330A is provided for each of the 32 regions HA.

[0049] Note that the shape of the heat generating portion 331A shown in FIG. 4 is schematic, and the actual shape may be different from this. The same applies to the positions and shapes of the pad portions 332A and 333A.

[0050] The configuration of the second sub-heater layer 330B will be described later, and first, the configuration of the main heater layer 350 will be described. Similar to the first sub-heater layer 330A, the main heater layer 350 is also divided into a plurality of regions, and it is possible to generate heat individually in each region. FIG. 5 shows an example of the division method of the main heater layer 350 in a top view. In this example, the main heater layer 350 is divided into a total of 4 regions HB.

[0051] The main heater layer 350 is configured as a linear heat generating portion 351, which is individually routed inside each region HB. That is, a total of 4 heat generating portions 351 are provided in this embodiment.

[0052] FIG. 6 shows an example of the heat generating portion 351 routed inside one region HB. In each region HB, a single linear heat generating portion 351 is routed along a path that evenly passes through substantially all of its range. The heat generating portion 351 is a portion that generates heat when supplied with power from the outside. The number of heat generating portions 351 (a total of 4) is less than the number of heat generating portions 331A (a total of 32).

[0053] Circular pad portions 352 and 353 are formed at both ends of the heating portion 351. The heating portion 351 and the pad portions 352 and 353 are formed, for example, by etching a thin metal foil, and the whole functions as one main heater layer 350. In other words, one main heater layer 350 is provided for each of the four regions HB.

[0054] Note that the shape of the heating portion 351 shown in FIG. 6 is schematic, and the actual shape may be different from this. The same applies to the positions of the pad portions 352 and 353.

[0055] FIG. 7 shows a schematic perspective view of the configuration of two regions HA, two heating portions 331A arranged therein, and a bypass layer 370 connected to the heating portion 331A. One of the two regions HA shown in FIG. 7 is hereinafter also referred to as "region HA1". The other region HA is hereinafter also referred to as "region HA2". Note that the shape of the heating portion 331A shown in FIG. 7 is schematic, and the actual shape may be different from this.

[0056] As described above, the bypass layer 370 is divided into a plurality of parts. In FIG. 7, only three of the bypass layers 370 divided into a plurality of parts are shown. Among the bypass layers 370 divided into three, the one marked with the reference numeral "371" in FIG. 7 is arranged at a position overlapping only one region HA in a top view. That is, it is individually arranged at a position directly below each region HA. The portion of the bypass layer 370 arranged in this way is hereinafter also referred to as "bypass layer 371".

[0057] Among the divided bypass layers 370, the one marked with the reference numeral "372" in FIG. 7 is arranged at a position overlapping both region HA1 and region HA2 in a top view. The portion of the bypass layer 370 arranged in this way is hereinafter also referred to as "bypass layer 372".

[0058] In the first sub-heater layer 330A disposed in the region HA1, the pad portion 332A at one end of the heat generating portion 331A is electrically connected to the bypass layer 371 directly below it. The pad portion 333A at the other end of the heat generating portion 331A is electrically connected to the bypass layer 372.

[0059] The same applies to the first sub-heater layer 330A disposed in the region HA2. The pad portion 332A at one end of the heat generating portion 331A is electrically connected to the bypass layer 371 directly below it. The pad portion 333A at the other end of the heat generating portion 331A is electrically connected to the bypass layer 372.

[0060] In addition, in this embodiment, the electrical connection of each part as described above is realized by welding the upper and lower layers to each other. For easy understanding of the configuration, in FIG. 7, each electric path 301 formed by welding is schematically drawn as a rod-shaped member extending linearly.

[0061] In addition, in the portion overlapping each welding portion in a top view, openings are formed in each of the layers (insulating layer 322, second sub-heater layer 330B, insulating layer 323, main heater layer 350, and insulating layer 324) between the first sub-heater layer 330A and the bypass layer 370, and the first sub-heater layer 330A and the bypass layer 370 are directly connected through the openings.

[0062] One end of the power supply portion 390 is connected to each of the bypass layers 371 from below in FIG. 7. A voltage is individually applied to each of these power supply portions 390 from an external DC power supply. Similarly, one end of the power supply portion 390 is connected to the bypass layer 372 from below in FIG. 7. This power supply portion 390 is grounded.

[0063] As described above, each of the first sub-heater layers 330A provided for each region HA has one pad portion 332A connected to an individual DC power supply via a bypass layer 371, and the other pad portion 333A grounded via a common bypass layer 372. The other first sub-heater layers 330A not shown in FIG. 7 are also connected to a DC power supply or the like with a similar configuration. By adopting such a configuration, it is possible to individually supply power to each of the plurality of first sub-heater layers 330A provided and adjust the calorific value generated in each part.

[0064] It is also possible to directly supply power to the first sub-heater layer 330A from the power supply unit 390 without passing through the bypass layer 370. However, by adopting a configuration in which power supply is performed via the bypass layer 370 as in the present embodiment, it is possible to increase the degree of freedom in arranging the power supply unit 390 and to combine the grounded power supply units 390 into one.

[0065] The power supply to each main heater layer 350 is also realized with a similar configuration as described above. Since the specific configuration is the same as that shown in FIG. 7, the description and illustration thereof are omitted.

[0066] The second sub-heater layer 330B will be described. As described above, the second sub-heater layer 330B is divided into a plurality of regions in the same manner as the first sub-heater layer 330A, and it is possible to generate heat individually in each region. FIG. 8 shows an example of the division method of the second sub-heater layer 330B in a top view.

[0067] The region HA shown in FIG. 8 is the same as the eight regions HA arranged at the outermost peripheral position among the plurality of regions HA shown in FIG. 3. The region HA arranged at such a position is hereinafter also referred to as "region HAA".

[0068] The second sub-heater layer 330B is configured as a linear heating part 331B, and in a top view, it is individually routed inside each region HAA. In the region HA other than the region HAA, the heating part 331B is not routed. That is, a total of eight heating parts 331B are provided in this embodiment.

[0069] FIG. 9(B) shows an example of the heating part 331B routed inside one region HAA. In each region HAA, a single linear heating part 331B is routed along a path that evenly passes through substantially all of its range. The heating part 331B is a part that generates heat upon receiving power supply from the outside, and corresponds to the "second heating part" of this embodiment.

[0070] Circular pad parts 332B and 333B are formed at both ends of the heating part 331B respectively. The heating part 331B and the pad parts 332B and 333B are formed, for example, by etching a thin metal foil, and the whole functions as a single second sub-heater layer 330B. In other words, one second sub-heater layer 330B is provided for each of the eight regions HAA in total.

[0071] Note that the shape of the heating part 331B shown in FIG. 9(B) is schematic, and the actual shape may be different from this. The same applies to the positions and shapes of the pad parts 332B and 333B.

[0072] In this embodiment, as described above, inside each region HAA in a top view, the heating part 331A of the first sub-heater layer 330A and the heating part 331B of the second sub-heater layer 330B are individually routed at different height positions from each other. The "height position" refers to the position in the direction perpendicular to the surface 110 which is the mounting surface. Inside the region HA other than the region HAA, only the heating part 331A of the first sub-heater layer 330A is routed, and the heating part 331B of the second sub-heater layer 330B is not routed.

[0073] The first sub-heater layer 330A shown in FIG. 9(A) and the second sub-heater layer 330B shown in FIG. 9(B) are arranged inside the same region HAA. That is, they are arranged within a range where they overlap each other in a top view. Also inside the other regions HAA, as in FIG. 9, the first sub-heater layer 330A and the first sub-heater layer 330A are arranged at different height positions from each other.

[0074] As described above, the heater unit 300 of the present embodiment includes a heating part 331A (first heating part) individually routed inside each region HA, and a heating part 331B (second heating part) individually routed inside a part of the region HA (region HAA) at a height position different from that of the heating part 331A.

[0075] As schematically shown in FIG. 9, the pad part 333A of the first sub-heater layer 330A and the pad part 333B of the second sub-heater layer 330B are electrically connected via an electric circuit 303. In the actual configuration, the two are directly connected by welding. An opening is formed in the insulating layer 322 between the pad part 333A and the pad part 333B at the portion overlapping the welding part in a top view, and the electric circuit 303 by welding is formed through the opening.

[0076] The pad part 332A of the first sub-heater layer 330A is electrically connected to the bypass layer 370 via the electric circuit 304 shown in FIG. 9. The bypass layer 370 to which the pad part 332A is connected is connected to a DC power supply, such as the bypass layer 371 in the example of FIG. 7.

[0077] Similarly, the pad part 332B of the second sub-heater layer 330B is also electrically connected to the bypass layer 370 via the electric circuit 305 shown in FIG. 9. The bypass layer 370 to which the pad part 332B is connected is grounded, such as the bypass layer 372 in the example of FIG. 7.

[0078] Circuit 304 and circuit 305 are formed in the same manner as circuit 301 in the example of FIG. 7. In the portion overlapping circuit 304 in a top view, openings are formed in each of the layers between the first sub-heater layer 330A and the bypass layer 370, and the first sub-heater layer 330A and the bypass layer 370 are directly connected by welding through the openings. Further, in the portion overlapping circuit 305 in a top view, openings are formed in each of the layers between the second sub-heater layer 330B and the bypass layer 370, and the second sub-heater layer 330B and the bypass layer 370 are directly connected by welding through the openings.

[0079] As described above, the heat generating portion 331A (first heat generating portion) and the heat generating portion 331B (second heat generating portion) routed inside the same region HAA are connected in series with each other.

[0080] The reason for such a configuration will be described. When the sub-heater layer 330 is divided into a plurality of regions HA as in the present embodiment, it is necessary to design at the time of design so that the heat generation performance in each region HA is appropriate according to its position and size.

[0081] For example, in the outer peripheral portion of the substrate W, the yield of the chips tends to be low because the temperature during processing tends to rise. Therefore, as in the example of FIG. 3, it is preferable to make the region HAA arranged at the outermost peripheral position smaller than the other regions HA to enable fine temperature control.

[0082] However, when the region HAA is made narrower than the others, the length of the heat generating portion routed in the region HAA becomes shorter and its resistance value becomes smaller, so there is a concern that the heat generation performance in the region HAA may become too large. Here, the "heat generation performance" refers to, for example, the amount of heat generation per unit area when a predetermined voltage is applied to the heat generating portion. As an index indicating the heat generation performance, for example, the reciprocal of the electrical resistance value of the heat generating portion can be used.

[0083] As a method for making the heat generation performance in the region HAA closer to the heat generation performance in other regions HA, it is conceivable to narrow the line width of the heat generating portion 331A routed in the region HAA. However, if the line width of the heat generating portion 331A is made too narrow, the possibility of disconnection increases. Thus, it has often been difficult to adjust the heat generation performance of the heat generating portion according to the position and size of the region HA by means of the line width or the like.

[0084] Therefore, in the heater unit 300 according to the present embodiment, in a part (region HAA) of the plurality of regions HA, the sub-heater layer 330 is arranged by being divided into two layers, a first sub-heater layer 330A and a second sub-heater layer 330B.

[0085] For example, when the heat generating portion 331A and the heat generating portion 331B are connected in series with each other as in the present embodiment, the total length of the heat generating portions routed in one region HAA becomes long. For this reason, without narrowing the line width of the heat generating portion 331A or the like, it is possible to increase the overall electrical resistance of the heat generating portion 331A and the heat generating portion 331B and arrange them inside one region HAA. That is, while narrowing the outermost peripheral region HAA to enable fine temperature adjustment, the heat generation performance in the region HAA can be made comparable to the heat generation performance in other regions HA. As a result, it becomes possible to easily perform control for making the in-plane temperature distribution uniform.

[0086] In the present embodiment, the heat generating portion 331A and the heat generating portion 331B routed inside the same region HAA are equal to each other in their respective line widths. By making the line widths of all the heat generating portions equal, the formation of the heat generating portions during manufacturing becomes easy. In addition, since there is no need to narrow the line width in part, disconnection in the heat generating portion 331A or the like can be prevented.

[0087] Furthermore, the region HA where both the heating part 331A and the heating part 331B are arranged may be only the outermost peripheral region HAA as in the present embodiment, or may be all the regions HA. Also, the heating part 331A and the heating part 331B arranged inside the same region HA may be electrically connected to each other as in the present embodiment, or may not be connected. For example, the power supply to each of the heating part 331A and the heating part 331B in the same region HA may be configured to be individually performed from the outside. By adopting such a configuration, for example, it becomes possible to increase the adjustment range of the calorific value in the region HA.

[0088] In the present embodiment, only the sub-heater layer 330 is divided into two layers, and the main heater layer 350 is a single layer. Instead of such a mode, the main heater layer 350 may also be configured to be divided into two layers in the same manner as the sub-heater layer 330. That is, even in a mode in which another heating part is routed at a height position different from that of the heating part 351 inside at least a part of the plurality of regions HB shown in FIG. 5.

[0089] Also, the heater unit 300 may have only the sub-heater layer 330 similar to the present embodiment, while not having the main heater layer 350.

[0090] The second embodiment will be described. Hereinafter, the points different from the first embodiment will be mainly described, and the description of the points common to the first embodiment will be omitted as appropriate.

[0091] FIG. 10 shows an example of the division method of the second sub-heater layer 330B in the present embodiment in a top view. The region HA shown in FIG. 10 is the same as the total 16 regions HA arranged at the central side among the plurality of regions HA shown in FIG. 3. These regions HA are obtained by excluding a total of 8 regions HAA arranged at the outermost periphery and a total of 8 regions HA arranged one inside thereof from the total 32 regions HA. The region HA arranged at such a central position is also referred to as "region HAB" hereinafter.

[0092] The second sub-heater layer 330B of the present embodiment is configured as a linear heating part 331B, similar to the first embodiment. The heating part 331B is individually routed inside each region HAB in a top view. In the region HA other than the region HAB, the heating part 331B is not routed. That is, a total of 16 heating parts 331B are provided in the present embodiment.

[0093] In the present embodiment, both the heating part 331A (first heating part) and the heating part 331B (second heating part) are routed inside the regions (i.e., region HAB) arranged at positions different from the outermost periphery among the plurality of regions HA.

[0094] FIG. 11(B) shows an example of the heating part 331B routed inside one region HAB. Note that the shape of the heating part 331B shown in FIG. 11(B) is schematic and different from the actual shape. The same applies to the positions and shapes of the pad parts 332B and 333B.

[0095] The first sub-heater layer 330A shown in FIG. 11(A) and the second sub-heater layer 330B shown in FIG. 11(B) are arranged inside the same region HAB. That is, they are arranged within a range where they overlap each other in a top view. Inside the other regions HAB, the first sub-heater layer 330A and the first sub-heater layer 330A are arranged at different height positions from each other, similar to FIG. 11.

[0096] As schematically shown in FIG. 11, between the pad part 332A of the first sub-heater layer 330A and the pad part 332B of the second sub-heater layer 330B, they are electrically connected via the electric circuit 306. The electric circuit 306 is also electrically connected to the bypass layer 370. The bypass layer 370 to which the pad part 332A etc. are connected is connected to a DC power supply, like the bypass layer 371 in the example of FIG. 7, for example.

[0097] In the actual configuration, the pad portion 332A, the pad portion 332B, and the bypass layer 370 are directly connected by welding. In the portion overlapping with the welded portion in the top view, openings are formed in each of the layers (insulating layer 322, second sub-heater layer 330B, insulating layer 323, main heater layer 350, and insulating layer 324) between the first sub-heater layer 330A and the bypass layer 370, and through the openings, an electric path 306 is formed by welding.

[0098] Between the pad portion 333A of the first sub-heater layer 330A and the pad portion 333B of the second sub-heater layer 330B, they are electrically connected via an electric path 307. The electric path 307 is also electrically connected to the bypass layer 370. The bypass layer 370 to which the pad portion 333A or the like is connected is grounded, such as the bypass layer 372 in the example of FIG. 7.

[0099] In the actual configuration, the pad portion 333A, the pad portion 333B, and the bypass layer 370 are directly connected by welding. In the portion overlapping with the welded portion in the top view, openings are formed in each of the layers (insulating layer 322, second sub-heater layer 330B, insulating layer 323, main heater layer 350, and insulating layer 324) between the first sub-heater layer 330A and the bypass layer 370, and through the openings, an electric path 307 is formed by welding.

[0100] As described above, the heat generating portion 331A (first heat generating portion) and the heat generating portion 331B (second heat generating portion) routed inside the same region HAB are connected in parallel with each other in this embodiment. Therefore, compared with the case where only the heat generating portion 331A is provided, the overall electrical resistance of the heat generating portions routed in one region HAB is smaller. For this reason, in each region HAB on the central side, the heat generating performance of the heat generating portion is higher.

[0101] As described above, the temperature of the outer peripheral portion of the substrate W is likely to increase during processing. Therefore, in the present embodiment, the heating portion 331B is provided in the central portion that is likely to be relatively low in temperature, and by enhancing the heat generation performance in this portion, the in-plane temperature distribution of the substrate W is made closer to being uniform. Thus, also in the present embodiment, similar to the first embodiment, the heat generation performance of each part of the heater unit 300 can be adjusted without narrowing the line width of the heating portion 331A or the like.

[0102] The region HA where both the heating portion 331A and the heating portion 331B connected in parallel to each other are arranged may be only the inner region HAB as in the present embodiment, may be only the outermost peripheral region HAA, or may be all the regions HA.

[0103] In the above, the configuration in which the heater for heating the dielectric substrate 100 is provided outside the dielectric substrate 100 in a unitized state as the heater unit 300 has been described. However, the configuration as described above can also be applied to a configuration in which the heater is provided inside the dielectric substrate 100.

[0104] That is, a sub-heater layer 330 or the like configured in the same manner as shown in FIGS. 9 and 11 or the like may be embedded inside the dielectric substrate 100 in the same manner as the adsorption electrode 130. In this case, the power supply unit 390 may be provided on the surface 120 side of the dielectric substrate 100, and the bypass layer 370 connecting between the power supply unit 390 and the heating portion 331A may be embedded inside the dielectric substrate 100 in the same manner as the heating portion 331A or the like. The circuit 304 connecting between the bypass layer 370 and the heating portion 331A may be configured as an elongated via (hole) filled with a conductor. The same applies to the other circuits 303, 305, 306, and 307.

[0105] The above-described embodiments have been explained with reference to specific examples. However, the present disclosure is not limited to these specific examples. Those obtained by appropriately making design changes by those skilled in the art to these specific examples are also included in the scope of the present disclosure as long as they have the features of the present disclosure. Each element included in each of the above-described specific examples, and its arrangement, conditions, shape, etc. are not limited to those illustrated and can be changed as appropriate. Each element included in each of the above-described specific examples can be appropriately combined as long as no technical contradiction occurs.

Description of Reference Numerals

[0106] 10: Electrostatic chuck 100: Dielectric substrate 110: Surface 300: Heater unit HA, HAA, HAB: Region 331A, 331B: Heating part W: Substrate

Claims

1. A dielectric substrate having a placement surface on which an object to be adsorbed is placed, and a heater for heating the dielectric substrate, wherein when viewed from a direction perpendicular to the placement surface, the heater includes a first heating portion individually routed inside each of a plurality of regions separated so as not to overlap each other, and a second heating portion individually routed inside at least a part of the regions at a height position different from that of the first heating portion, and an electrostatic chuck characterized by including the second heating portion.

2. The electrostatic chuck according to claim 1, wherein the first heating portion and the second heating portion routed inside the same region are connected in series with each other.

3. The electrostatic chuck according to claim 1, wherein the first heating portion and the second heating portion routed inside the same region are connected in parallel with each other.

4. The electrostatic chuck according to claim 2 or 3, wherein the first heating portion and the second heating portion routed inside the same region are equal to each other in line width.

5. When viewed from a direction perpendicular to the placement surface, both the first heating portion and the second heating portion are routed inside the outermost peripheral position among the plurality of regions, and the electrostatic chuck according to claim 1 is characterized in that.

6. When viewed from a direction perpendicular to the placement surface, both the first heating portion and the second heating portion are routed inside a position different from the outermost periphery among the plurality of regions, and the electrostatic chuck according to claim 1 is characterized in that.

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