electrostatic chuck

Abstract

To provide an electrostatic chuck capable of improving uniformity of temperature distribution in a plane of an object to be processed.SOLUTION: An electrostatic chuck comprises a base plate including a spiral communication passage permitting the passage of a coolant, a first heater element including a plurality of first zones arranged in a radial direction and a circumferential direction, and a plurality of first power feeding terminals for feeding power to the plurality of first zones. The plurality of first zones includes a first heater line for producing heat and a pair of first power feeding parts for feeding power to the first heater line. The pair of first power feeding parts is electrically connected to the plurality of first power feeding terminals. The plurality of first power feeding terminals includes a first annular portion arranged on a first virtual circle and a second annular portion located inside the first annular portion and arranged on a second virtual circle. When viewed along a lamination direction, the communication passage includes a first circulation portion surrounding a periphery of the second annular portion between the first annular portion and the second annular portion.SELECTED DRAWING: Figure 11

Description

Technical Field

[0001] Aspects of the present invention generally relate to electrostatic chucks.

Background Art

[0002] Electrostatic chucks on which objects to be processed such as semiconductor wafers and glass substrates are placed are known. Electrostatic chucks are used as means for adsorbing and holding an object to be processed in a plasma processing chamber of a semiconductor manufacturing apparatus that performs, for example, etching, CVD (Chemical Vapor Deposition), sputtering, ion implantation, or ashing. An electrostatic chuck applies electrostatic adsorption power to a built-in electrode, for example, and adsorbs a substrate such as a silicon wafer by electrostatic force.

[0003] An electrostatic chuck has a ceramic dielectric substrate having a placement surface on which an object to be processed is placed, and a base plate that supports the ceramic dielectric substrate. A refrigerant flow path may be provided in this base plate in order to cool the object to be processed.

[0004] On the other hand, as a method for controlling the temperature distribution within the plane of an object to be processed, a method using an electrostatic chuck incorporating a heater (heating element) is known. For example, the heater is divided into a plurality of zones capable of independently controlling the temperature. Thereby, the temperature distribution within the plane of the object to be processed (the placement surface of the object to be processed) can be controlled more finely. The number of such zones has been increasing in recent years, and may exceed 100, for example. In order to independently control the temperature of each zone, the number of power supply terminals for supplying power to each zone is also increasing. Depending on the arrangement of the power supply terminals and the refrigerant flow path, the uniformity of the temperature distribution within the plane of the object to be processed may decrease.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] This invention was made based on the recognition of the above problem and aims to provide an electrostatic chuck that can improve the uniformity of the in-plane temperature distribution of an object being processed. [Means for solving the problem]

[0007] The first invention comprises a ceramic dielectric substrate on which an object to be processed is placed, a base plate that supports the ceramic dielectric substrate and has an upper surface on the side of the ceramic dielectric substrate and a lower surface opposite to the upper surface, the base plate having a spiral-shaped connecting passage provided between the upper surface and the lower surface through which a refrigerant can pass, a first heater element including 20 or more first zones arranged radially and circumferentially, and a plurality of first power supply terminals for supplying power to the plurality of first zones, each of the plurality of first zones including a first heater line that generates heat when current flows through it, and a pair of first power supply units that supply power to the first heater line, the number of the plurality of first power supply terminals is equal to or greater than the number of first zones, the pair of first power supply units is electrically connected to the plurality of first power supply terminals, and the plurality of first power supply terminals are electrically connected to the plurality of first The electrostatic chuck comprises: a first annular portion including a portion of first power supply terminals among the power supply terminals, wherein the portion of power supply terminals included in the first annular portion is arranged on a first virtual circle, and the number of the portion of first power supply terminals included in the first annular portion is at least 7; and a second annular portion located inside the first annular portion, including another portion of first power supply terminals among the plurality of first power supply terminals, wherein the other portion of first power supply terminals included in the second annular portion is arranged on a second virtual circle, and the number of the other portion of first power supply terminals included in the second annular portion is at least 7; wherein the communication passage includes a first circular portion surrounding the second annular portion between the first annular portion and the second annular portion when viewed along the stacking direction of the base plate and the ceramic dielectric substrate.

[0008] According to this electrostatic chuck, the first heater element is provided with 20 or more first zones, and the multiple first power supply terminals include a first annular portion and a second annular portion. The first circumferential portion of the communication passage in the base plate is positioned between the first annular portion and the second annular portion in a plan view. This suppresses temperature unevenness in the radial and circumferential directions caused by the position of the first power supply terminals, and improves the uniformity of the temperature distribution in the plane.

[0009] The second invention is an electrostatic chuck characterized in that, in the first invention, the plurality of first zones include a first annular zone region which includes a portion of the plurality of first zones, the portion of first zones included in the first annular zone region which are arranged in the circumferential direction, the portion of first power supply terminals included in the first annular portion which are first power supply terminals which supply power to the portion of first zones included in the first annular zone region, and if the number of the portion of first zones included in the first annular zone region is N1, then the number of the portion of first power supply terminals included in the first annular portion which is greater than 2 × N1 × 0.6.

[0010] With this electrostatic chuck, for example, more than 60% of the first power supply terminals that supply power to multiple first zones included in the first annular zone region are included in the first annular portion. This makes it possible to further improve the uniformity of the temperature distribution in the plane.

[0011] The third invention is an electrostatic chuck characterized in that, in the first invention, the plurality of first zones include a first annular zone region which includes a portion of the plurality of first zones, the portion of zones included in the first annular zone region which are arranged in the circumferential direction, the portion of first power supply terminals included in the first annular portion which are first power supply terminals which supply power to the portion of first zones included in the first annular zone region, and the zone center of the first annular zone region which coincides with at least one of the first center of the first virtual circle and the second center of the second virtual circle.

[0012] With this electrostatic chuck, the center of at least one of the first virtual circle and the second virtual circle coincides with the zone center of the first annular zone region. This suppresses the bias in the position of the first power supply terminal, which is included in at least one of the first annular portion and the second annular portion, relative to the first zone included in the first annular zone region. This further improves the uniformity of the temperature distribution in the plane.

[0013] The fourth invention is an electrostatic chuck in which, in the third invention, at least one of the members is the first center of the first virtual circle.

[0014] This electrostatic chuck makes it possible to suppress the bias in the position of the first power supply terminal contained in the first annular portion relative to the first zone contained in the first annular zone region. The first annular portion is located outside the second annular portion. Therefore, for example, the uniformity of the temperature distribution on the outer periphery of the mounting surface can be further improved.

[0015] The fifth invention is an electrostatic chuck characterized in that, in any one of the first to fourth inventions, some of the first power supply terminals included in the first annular portion are evenly arranged in the circumferential direction.

[0016] This electrostatic chuck allows for improved uniformity of the temperature distribution in the circumferential direction.

[0017] The sixth invention is an electrostatic chuck characterized in that, in any one of the first to fifth inventions, a second heater element comprising a plurality of second zones arranged at least radially, and a plurality of second power supply terminals for supplying power to the plurality of second zones, each of the plurality of second zones comprising a second heater line that generates heat when current flows through it, and a pair of second power supply units that supply power to the second heater line, the number of the plurality of second power supply terminals being equal to or greater than the number of second zones, each of the pair of second power supply units being electrically connected to one of the plurality of second power supply terminals, and at least a portion of the plurality of second power supply terminals overlapping with at least one of the first virtual circle and the second virtual circle when viewed along the stacking direction.

[0018] This electrostatic chuck suppresses temperature variations caused by the position of the second power supply terminal, thereby improving the uniformity of the temperature distribution within the plane.

[0019] The seventh invention is an electrostatic chuck according to the sixth invention, characterized in that the number of the plurality of first zones is larger than the number of the plurality of second zones.

[0020] According to this electrostatic chuck, since the number of the first zones is relatively large, for example, the number of the first power supply terminals is larger than the number of the second power supply terminals. Temperature unevenness in the radial direction and circumferential direction caused by the positions of the first power supply terminals is suppressed, and the uniformity of the in-plane temperature distribution can be further improved.

Effect of the Invention

[0021] According to an aspect of the present invention, there is provided an electrostatic chuck capable of improving the uniformity of the in-plane temperature distribution of an object to be processed.

Brief Description of the Drawings

[0022] [Figure 1] It is a perspective view schematically showing an electrostatic chuck according to an embodiment. [Figure 2] FIGS. 2(a) and 2(b) are cross-sectional views schematically showing a part of the electrostatic chuck according to the embodiment. [Figure 3] It is a plan view schematically showing a second heater element according to the embodiment. [Figure 4] It is a plan view schematically showing a part of a main zone of a second heater element according to the embodiment. [Figure 5] It is a plan view schematically showing a first heater element according to the embodiment. [Figure 6] It is a plan view schematically showing a part of a subzone of a first heater element according to the embodiment. [[ID=3...]] [Figure 7] It is a plan view schematically showing a first heater element and a second heater element according to the embodiment. [Figure 8] It is an exploded cross-sectional view schematically showing a heater part according to the embodiment. [Figure 9] It is a plan view schematically showing a part of a base plate and a heater part according to the embodiment. [[ID=...]> [Figure 10]This is a schematic plan view showing a part of the base plate and heater section according to the embodiment. [Figure 11] This is a schematic plan view showing a part of the base plate and heater section according to the embodiment. [Figure 12] This is a schematic plan view showing a part of the heater section according to the embodiment. [Figure 13] This is a schematic plan view showing a part of the heater section according to the embodiment. [Figure 14] This is a schematic plan view showing a part of the heater section according to the embodiment. [Figure 15] This is a schematic plan view showing a base plate and a part of the heater section according to a modified embodiment. [Figure 16] This is a schematic plan view showing a base plate and a part of the heater section according to a modified embodiment. [Figure 17] This is a schematic plan view showing a base plate and a part of the heater section according to a modified embodiment. [Figure 18] This is a schematic plan view showing a part of the heater section according to a modified embodiment. [Figure 19] This is a schematic plan view showing a part of the heater section according to a modified embodiment. [Figure 20] This is a schematic diagram representing a simulation model of the temperature distribution on the surface of a ceramic dielectric substrate for an electrostatic chuck. [Figure 21] This is a schematic plan view showing the simulation results of the temperature distribution on the surface of the ceramic dielectric substrate of an electrostatic chuck. [Figure 22] Figures 22(a) and 22(b) are graphs showing the simulation results of the temperature distribution on the surface of the ceramic dielectric substrate of the electrostatic chuck. [Modes for carrying out the invention]

[0023] Embodiments of the present invention will be described below with reference to the drawings. In each drawing, similar components are denoted by the same reference numerals, and detailed descriptions are omitted as appropriate. Figure 1 is a schematic perspective view of an electrostatic chuck according to an embodiment. Figures 2(a) and 2(b) are schematic cross-sectional views showing a part of the electrostatic chuck according to the embodiment. Figure 1 shows a cross-sectional view of a portion of the electrostatic chuck for illustrative purposes. Figure 2(a) is a cross-sectional view taken along the line A1-A1 shown in Figure 1. Figure 2(b) is an enlarged view of region B2 shown in Figure 2(a). Note that the object W to be processed is omitted in Figure 2(b).

[0024] As shown in Figures 1, 2(a), and 2(b), the electrostatic chuck 10 according to this embodiment comprises a ceramic dielectric substrate 100, a heater section 200, and a base plate 300.

[0025] The ceramic dielectric substrate 100 is a flat substrate made of, for example, a polycrystalline ceramic sintered body, and has a first main surface 101 (mounting surface) on which a workpiece W such as a semiconductor wafer is placed, and a second main surface 102 on the opposite side of the first main surface 101.

[0026] In this specification, the direction perpendicular to the first main surface 101 is defined as the Z direction. In other words, the Z direction is the direction connecting the first main surface 101 and the second main surface 102. In other words, the Z direction is the stacking direction from the base plate 300 toward the ceramic dielectric substrate 100. Furthermore, one of the directions perpendicular to the Z direction is defined as the X direction, and the direction perpendicular to both the Z direction and the X direction is defined as the Y direction. In this specification, "in-plane" refers to, for example, the XY plane. Also, in this specification, "plan view" refers to the view along the Z direction.

[0027] Examples of crystalline materials included in the ceramic dielectric substrate 100 include Al2O3, AlN, SiC, Y2O3, and YAG. By using such materials, the infrared transmittance, thermal conductivity, dielectric strength, and plasma durability of the ceramic dielectric substrate 100 can be improved.

[0028] An electrode layer 111 is provided inside the ceramic dielectric substrate 100. The electrode layer 111 is interposed between the first main surface 101 and the second main surface 102. In other words, the electrode layer 111 is formed to be inserted into the ceramic dielectric substrate 100. The electrode layer 111 is integrally sintered into the ceramic dielectric substrate 100.

[0029] Furthermore, the electrode layer 111 is not limited to being interposed between the first main surface 101 and the second main surface 102, but may also be attached to the second main surface 102.

[0030] The electrostatic chuck 10 generates an electric charge on the first main surface 101 side of the electrode layer 111 by applying an adsorption and holding voltage to the electrode layer 111, and adsorbs and holds the object to be processed W by electrostatic force.

[0031] The electrode layer 111 is provided along the first main surface 101 and the second main surface 102. The electrode layer 111 is an adsorption electrode for adsorbing and holding the object to be processed W. The electrode layer 111 may be unipolar or bipolar. Furthermore, the electrode layer 111 may be tripolar or other multipolar. The number and arrangement of the electrode layers 111 are selected as appropriate.

[0032] The base plate 300 is provided on the second main surface 102 side of the ceramic dielectric substrate 100 and supports the ceramic dielectric substrate 100. As shown in Figure 2(a), the base plate 300 has an upper surface 302 on the side facing the ceramic dielectric substrate 100 and a lower surface 303 on the opposite side of the upper surface 302. The base plate 300 includes a communication passage 301 (refrigerant flow path) provided between the upper surface 302 and the lower surface 303. In other words, the communication passage 301 is provided inside the base plate 300. Examples of materials for the base plate 300 include aluminum, aluminum alloy, titanium, and titanium alloy.

[0033] The base plate 300 plays a role in regulating the temperature of the ceramic dielectric substrate 100. For example, when cooling the ceramic dielectric substrate 100, a cooling medium is introduced into the communication passage 301, passes through the communication passage 301, and then flows out from the communication passage 301. In this way, the cooling medium absorbs the heat of the base plate 300, thereby cooling the ceramic dielectric substrate 100 mounted on it. In other words, the communication passage 301 functions as a refrigerant channel through which the refrigerant can pass.

[0034] Furthermore, protrusions 113 are provided on the first main surface 101 side of the ceramic dielectric substrate 100 as needed. Grooves 115 are provided between adjacent protrusions 113. The grooves 115 are in communication with each other. A space is formed between the back surface of the object to be processed W mounted on the electrostatic chuck 10 and the grooves 115.

[0035] An introduction channel 321 is connected to the groove 115, penetrating the base plate 300 and the ceramic dielectric substrate 100. When a transfer gas such as helium (He) is introduced through the introduction channel 321 while the object to be processed W is adsorbed and held, the transfer gas flows into the space between the object to be processed W and the groove 115, allowing the object to be directly heated or cooled by the transfer gas.

[0036] The heater unit 200 heats the ceramic dielectric substrate 100. By heating the ceramic dielectric substrate 100, the heater unit 200 heats the object to be processed W through the ceramic dielectric substrate 100. In this example, the heater unit 200 is provided between the first main surface 101 and the second main surface 102. That is, the heater unit 200 is provided inside the ceramic dielectric substrate 100. The heater unit 200 is formed to be inserted into the ceramic dielectric substrate 100. In other words, the heater unit 200 is built into the ceramic dielectric substrate 100.

[0037] The heater unit 200 is provided with a power supply terminal 280 (sub-power supply terminal 281 or main power supply terminal 282), which will be described later. As shown in Figure 2(a), the power supply terminal 280 is electrically connected to the power supply 20 via a conductive part 21 (wiring, probe, socket, or terminal, etc.). Current is passed from the power supply 20 to the heater line of the heater unit 200 via the conductive part 21 and the power supply terminal 280, causing the heater line to heat up.

[0038] The base plate 300 is provided with terminal holes 300p for arranging at least one of the power supply terminals 280 and the conductive portion 21. The terminal holes 300p are positioned according to the location of the power supply terminals 280. For example, the terminal holes 300p include a portion that overlaps with the power supply terminals 280 in the Z direction and extends in the Z direction. A portion of the terminal holes 300p is aligned with the communication passage 301 in the XY plane. The terminal holes 300p extend, for example, from the upper surface 302 to the lower surface 303 of the base plate 300 and penetrate the base plate 300.

[0039] As will be described later, multiple power supply terminals 280 are provided. Therefore, for example, multiple terminal holes 300p are provided corresponding to each of the multiple power supply terminals 280. For example, at least one of the power supply terminal 280 and the conductive part 21 is placed in each of the multiple terminal holes 300p.

[0040] The heater unit 200 may be separate from the ceramic dielectric substrate 100. In this case, it is provided between the ceramic dielectric substrate 100 and the base plate 300. For example, an adhesive layer is provided between the base plate 300 and the heater unit 200. An adhesive layer is provided between the heater unit 200 and the ceramic dielectric substrate 100. Examples of materials for the adhesive layer include heat-resistant resins such as silicone, which have relatively high thermal conductivity.

[0041] The heater section 200 includes a first heater element 231 and a second heater element 232, which will be described later.

[0042] Figure 3 is a schematic plan view of the second heater element according to the embodiment. Figure 3 shows the second heater element 232 projected onto a plane perpendicular to the Z direction. As shown in Figure 3, the second heater element 232 has multiple main zones 600 (second zones) divided at least radially in the Dr direction. In other words, the multiple main zones 600 are arranged at least radially in the Dr direction. In the second heater element 232, independent temperature control is performed in each main zone 600.

[0043] In this specification, "radial direction Dr" refers to the direction from the center of the heater element (e.g., the first heater element 231) towards the outer circumference along the radius. "Circumferential direction Dc" refers to the direction along the outer circumference of the heater element (e.g., the first heater element 231). The radial direction Dr may also be the radial direction of the ceramic dielectric substrate 100 or the base plate 300. The circumferential direction Dc may also be the circumferential direction of the ceramic dielectric substrate 100 or the base plate 300.

[0044] In this example, the multiple main zones 600 have three main zones 601 to 603 aligned in the radial direction Dr. That is, the second heater element 232 is divided into three in the radial direction Dr. Each main zone 600 is arranged in the order of main zone 601, main zone 602, and main zone 603, moving outward in the radial direction Dr from the center CT2 of the second heater element 232.

[0045] In this example, the main zone 601 is circular in shape with center CT2 in a plan view. The main zone 602 is annular in shape with center CT2 and is located outside the main zone 601 in a plan view. The main zone 603 is annular in shape with center CT2 and is located outside the main zone 602 in a plan view.

[0046] In this example, the radial width LM1 of main zone 601, the radial width LM2 of main zone 602, and the radial width LM3 of main zone 603 are the same. However, the widths LM1 to LM3 may be different.

[0047] The number of main zones 600 and their shape in plan view are arbitrary. Furthermore, the main zones 600 may be divided in the circumferential direction Dc, or in the circumferential direction Dc and the radial direction Dr. The configuration within each main zone 600 will be described later.

[0048] Note that in Figure 3, for convenience, the radial ends Dr of each main zone 600 are shown touching, but in reality, there is a gap between them (i.e., a section where the main heater line 232c is not provided), and the radial ends Dr of adjacent main zones do not touch. The same applies to subsequent figures.

[0049] Figure 4 is a schematic plan view showing a portion of the main zone of the second heater element according to the embodiment. The main zone 600 includes a second heater line (main heater line 232c) and a pair of second power supply units (first main power supply unit 232a and second main power supply unit 232b). The main heater line 232c is electrically connected to the first main power supply unit 232a and the second main power supply unit 232b. The first main power supply unit 232a is provided at one end of the main heater line 232c, and the second main power supply unit 232b is provided at the other end of the main heater line 232c. Each of the first main power supply unit 232a and the second main power supply unit 232b is, for example, a conductive part (metal film, metal foil) that is wider than the main heater line 232c. The main heater line 232c is, for example, a conductive part (metal film, metal foil) that is relatively narrow. The main heater line 232c generates heat when current flows through it. The first main power supply unit 232a and the second main power supply unit 232b supply power to the main heater line 232c. One main zone 600 has one first main power supply unit 232a, one second main power supply unit 232b, and one main heater line 232c. The main zone 600 is a region composed of a continuous main heater line 232c connecting the first main power supply unit 232a and the second main power supply unit 232b.

[0050] The main heater lines 232c that make up each main zone 600 are independent of each other. This allows a different voltage to be applied to each main zone 600 (main heater line 232c). Therefore, the output (amount of heat generated) can be controlled independently for each main zone 600. In other words, each main zone 600 is a heater unit that can perform independent temperature control, and the second heater element 232 is an assembly of heater units having multiple such heater units.

[0051] Figure 5 is a schematic plan view of the first heater element according to the embodiment. Figure 5 shows the first heater element 231 projected onto a plane perpendicular to the Z direction. As shown in Figure 5, in this example, the first heater element 231 has a plurality of subzones 700 (first zones) divided into radial Dr and circumferential Dc directions. In other words, the plurality of subzones 700 are arranged in the radial Dr and circumferential Dc directions. In the first heater element 231, independent temperature control is performed in each subzone 700.

[0052] In this example, the multiple subzones 700 include a first region 701 consisting of subzone 701a, a second region 702 consisting of subzones 702a to 702h aligned in the circumferential direction Dc, a third region 703 consisting of subzones 703a to 703h aligned in the circumferential direction Dc, a fourth region 704 consisting of subzones 704a to 704h aligned in the circumferential direction Dc, and a fifth region 705 consisting of subzones 705a to 705h aligned in the circumferential direction Dc. In other words, the first heater element 231 is divided into five parts in the radial direction Dr. Furthermore, the second region 702 to the fifth region 705 are each divided into eight parts in the circumferential direction Dc. The first to fifth regions 705 are arranged in the order of first region 701, second region 702, third region 703, fourth region 704, and fifth region 705, moving outward in the radial direction Dr from the center CT1 of the first heater element 231.

[0053] The first region 701 (subzone 701a) is circular in shape with center CT1 in a plan view. Each of the second region 702 to the fifth region 705 is annular in shape with center CT1 in a plan view. In a plan view, the second region 702 is located outside the first region 701, the third region 703 is located outside the second region 702, the fourth region 704 is located outside the third region 703, and the fifth region 705 is located outside the fourth region 704.

[0054] The second region 702 contains some of the subzones 700 (subzones 702a to 702h) of the multiple subzones 700. Subzones 702a to 702h are arranged in the circumferential direction Dc. Specifically, in the second region 702, subzones 702a to 702h are arranged clockwise in the order of subzone 702a, subzone 702b, subzone 702c, subzone 702d, subzone 702e, subzone 702f, subzone 702g, and subzone 702h. In this example, subzones 702a to 702h are each located outside subzone 701a. Subzones 702a to 702h each constitute a part of the annular second region 702. In the following description, the second region 702 may be referred to as the fourth annular zone region Z14.

[0055] The third region 703 contains some of the subzones 700 (subzones 703a to 703h) of the multiple subzones 700. Subzones 703a to 703h are arranged in the circumferential direction Dc. Specifically, in the third region 703, subzones 703a to 703h are arranged clockwise in the order of subzone 703a, subzone 703b, subzone 703c, subzone 703d, subzone 703e, subzone 703f, subzone 703g, and subzone 703h. In this example, subzone 703a is located outside subzone 702a. Subzone 703b is located outside subzone 702b. Subzone 703c is located outside subzone 702c. Subzone 703d is located outside subzone 702d. Subzone 703e is located outside subzone 702e. Subzone 703f is located outside subzone 702f. Subzone 703g is located outside subzone 702g. Subzone 703h is located outside subzone 702h. Subzones 703a to 703h each constitute a part of the annular third region 703. In the following description, the third region 703 may be referred to as the third annular zone region Z13.

[0056] The fourth region 704 contains some of the subzones 700 (subzones 704a to 704h) of the multiple subzones 700. Subzones 704a to 704h are arranged in the circumferential direction Dc. Specifically, in the fourth region 704, subzones 704a to 704h are arranged clockwise in the order of subzone 704a, subzone 704b, subzone 704c, subzone 704d, subzone 704e, subzone 704f, subzone 704g, and subzone 704h. In this example, subzone 704a is located outside subzone 703a. Subzone 704b is located outside subzone 703b. Subzone 704c is located outside subzone 703c. Subzone 704d is located outside subzone 703d. Subzone 704e is located outside subzone 703e. Subzone 704f is located outside subzone 703f. Subzone 704g is located outside subzone 703g. Subzone 704h is located outside subzone 703h. Subzones 704a to 704h each constitute a part of the annular fourth region 704. In the following description, the fourth region 704 may be referred to as the second annular zone region Z12.

[0057] The fifth region 705 contains some of the subzones 700 (subzones 705a to 705h) of the multiple subzones 700. Subzones 705a to 705h are arranged in the circumferential direction Dc. Specifically, in the fifth region 705, subzones 705a to 705h are arranged clockwise in the order of subzone 705a, subzone 705b, subzone 705c, subzone 705d, subzone 705e, subzone 705f, subzone 705g, and subzone 705h. In this example, subzone 705a is located outside subzone 704a. Subzone 705b is located outside subzone 704b. Subzone 705c is located outside subzone 704c. Subzone 705d is located outside subzone 704d. Subzone 705e is located outside subzone 704e. Subzone 705f is located outside subzone 704f. Subzone 705g is located outside subzone 704g. Subzone 705h is located outside subzone 704h. Subzones 705a to 705h each constitute a part of the annular fifth region 705. In the following description, the fifth region 705 may be referred to as the first annular zone region Z11.

[0058] In this example, the radial width LS1 (radius) of the first region 701, the radial width LS2 of the second region 702, the radial width LS3 of the third region 703, the radial width LS4 of the fourth region 704, and the radial width LS5 of the fifth region 705 are all the same. The widths LS1 to LS5 may be different from each other.

[0059] The number of subzones 700 is greater than the number of main zones 600. In other words, the first heater element 231 is divided into more zones than the second heater element 232. For example, the number of subzones 700 is 20 or more. In this example, the number of subzones 700 is 33, and the number of main zones 600 is 3. There is no particular upper limit to the number of subzones 700, but it is approximately 200.

[0060] By increasing the number of subzones 700 in the first heater element 231 to more than the number of main zones 600 in the second heater element 232, the first heater element 231 can control the temperature of a narrower area than the second heater element 232. This allows for finer temperature adjustment by the first heater element 231, improving the uniformity of the temperature distribution within the plane of the object W being processed. The number of subzones 700 and their shape in plan view can be arbitrary.

[0061] Note that in Figure 5, for convenience, the radial ends Dr of each subzone 700 are shown touching, but in reality, there are gaps between them (i.e., areas where the subheater line 231c is not provided), and the radial ends Dr of adjacent subzones 700 do not touch. The same applies to subsequent figures.

[0062] Figure 6 is a schematic plan view showing a portion of the subzone of the first heater element according to the embodiment. The subzone 700 includes a first heater line (subheater line 231c) and a pair of first power supply units (first sub-power supply unit 231a and second sub-power supply unit 231b). The subheater line 231c is electrically connected to the first sub-power supply unit 231a and the second sub-power supply unit 231b. The first sub-power supply unit 231a is provided at one end of the subheater line 231c, and the second sub-power supply unit 231b is provided at the other end of the subheater line 231c. Each of the first sub-power supply unit 231a and the second sub-power supply unit 231b is, for example, a conductive part (metal film) that is wider than the subheater line 231c. The subheater line 231c is, for example, a conductive part (metal film) that is relatively narrow. The subheater line 231c generates heat when current flows through it. The first sub-power supply unit 231a and the second sub-power supply unit 231b supply power to the sub-heater line 231c. One sub-zone 700 has one first sub-power supply unit 231a, one second sub-power supply unit 231b, and one sub-heater line 231c. The sub-zone 700 is a region composed of a continuous sub-heater line 231c connecting the first sub-power supply unit 231a and the second sub-power supply unit 231b.

[0063] The subheater lines 231c that make up each subzone 700 are independent of each other. This allows a different voltage to be applied to each subzone 700 (subheater line 231c). Therefore, the output (amount of heat generated) can be controlled independently for each subzone 700. In other words, each subzone 700 is a heater unit that can perform independent temperature control, and the first heater element 231 is an assembly of heater units having multiple such heater units.

[0064] Figure 7 is a schematic plan view showing the first heater element and the second heater element according to the embodiment. Figure 7 shows the second heater element 232 described in relation to Figure 3 and the first heater element 231 described in relation to Figure 5 projected onto a plane perpendicular to the Z direction.

[0065] The first heater element 231 and the second heater element 232 are arranged such that, for example, the center CT1 of the first heater element 231 and the center CT2 of the second heater element 232 overlap in the Z direction. Also, in this case, the outer edge 231e of the first heater element 231 and the outer edge 232e of the second heater element 232 overlap in the Z direction. For example, the outer edge 701β of the first region 701 and the inner edge 702α of the second region 702 each overlap with the main zone 601 in the Z direction. For example, the outer edge 702β of the second region 702 and the inner edge 703α of the third region 703 each overlap with the main zone 601 or the main zone 602 in the Z direction. For example, the outer edge 703β of the third region 703 and the inner edge 704α of the fourth region 704 each overlap with the main zone 602 in the Z direction. For example, the outer edge 704β of the fourth region 704 and the inner edge 705α of the fifth region 705 each overlap with the main zone 603 in the Z direction.

[0066] Figure 8 is an exploded cross-sectional view schematically showing the heater section according to the embodiment. Figure 8 corresponds to the cross-section along line L1 shown in Figure 7. In Figure 8, the case in which the heater section 200 is provided between the first main surface 101 and the second main surface 102 of the ceramic dielectric substrate 100 is explained as an example, as shown in Figure 2. In this example, the heater section 200 includes a first insulating layer 220, a first heater element 231, a second insulating layer 240, a second heater element 232, a third insulating layer 245, a bypass layer 250, a fourth insulating layer 260, and a power supply terminal 280.

[0067] Furthermore, if the heater section 200 is provided between the ceramic dielectric substrate 100 and the base plate 300, the heater section 200 may include a support plate located below the fourth insulating layer 260 and a support plate located above the first insulating layer 220. The support plate sandwiches and supports the first insulating layer 220, the first heater element 231, the second insulating layer 240, the second heater element 232, the third insulating layer 245, the bypass layer 250, and the fourth insulating layer 260. The support plate may also function as a heat equalization plate.

[0068] The first heater element 231 is provided between the first insulating layer 220 and the fourth insulating layer 260. When the heater section 200 is embedded in the ceramic dielectric substrate 100, the ceramic dielectric substrate 100 may also serve as the first insulating layer 220.

[0069] The second insulating layer 240 is provided between the first heater element 231 and the fourth insulating layer 260. The second heater element 232 is provided between the second insulating layer 240 and the fourth insulating layer 260. Thus, the second heater element 232 is provided on a different layer from the layer on which the first heater element 231 is provided. At least a portion of the second heater element 232 overlaps with the first heater element 231 in the Z direction. The third insulating layer 245 is provided between the second heater element 232 and the fourth insulating layer 260. The bypass layer 250 is provided between the third insulating layer 245 and the fourth insulating layer 260.

[0070] The first heater element 231 is, in other words, provided between the first insulating layer 220 and the second insulating layer 240. The second heater element 232 is, in other words, provided between the second insulating layer 240 and the third insulating layer 245. The bypass layer 250 is, in other words, provided between the third insulating layer 245 and the fourth insulating layer 260.

[0071] The first heater element 231 contacts, for example, the first insulating layer 220 and the second insulating layer 240, respectively. The second heater element 232 contacts, for example, the second insulating layer 240 and the third insulating layer 245, respectively. The bypass layer 250 contacts, for example, the third insulating layer 245 and the fourth insulating layer 260, respectively.

[0072] The bypass layer 250 and the fourth insulating layer 260 are provided as needed and can be omitted. In the following explanation, we will use the case where the heater section 200 has a bypass layer 250 and a fourth insulating layer 260 as an example.

[0073] As the material for the first insulating layer 220, for example, insulating materials such as resin or ceramic can be used. Examples of the first insulating layer 220 being made of resin include polyimide and polyamide-imide. Examples of the first insulating layer 220 being made of ceramic include Al2O3, AlN, SiC, Y2O3, and YAG. The thickness (length in the Z direction) of the first insulating layer 220 is, for example, about 0.01 mm or more and 0.20 mm or less. The first insulating layer 220 electrically insulates the ceramic dielectric substrate 100 from the first heater element 231. In this way, the first insulating layer 220 has the function of electrical insulation. The first insulating layer 220 may also have other functions, such as a heat conduction function or a diffusion prevention function.

[0074] The material and thickness of the second insulating layer 240 are approximately the same as those of the first insulating layer 220. The material and thickness of the third insulating layer 245 are approximately the same as those of the first insulating layer 220. The material and thickness of the fourth insulating layer 260 are approximately the same as those of the first insulating layer 220.

[0075] The second insulating layer 240 electrically insulates the first heater element 231 and the second heater element 232. Thus, the second insulating layer 240 has an electrical insulating function. The second insulating layer 240 may also have other functions, such as a heat conduction function or a diffusion prevention function.

[0076] The third insulating layer 245 electrically insulates the second heater element 232 from the bypass layer 250. Thus, the third insulating layer 245 has an electrical insulating function. The third insulating layer 245 may also have other functions, such as a heat conduction function or a diffusion prevention function.

[0077] The fourth insulating layer 260 electrically insulates the bypass layer 250 from the ceramic dielectric substrate 100. Thus, the fourth insulating layer 260 has an electrical insulating function. The fourth insulating layer 260 may also have other functions, such as a heat conduction function or a diffusion prevention function.

[0078] When the first heater element 231 is embedded in the ceramic dielectric substrate 100, examples of materials for the first heater element 231 include metals containing at least one of titanium, chromium, nickel, copper, aluminum, molybdenum, tungsten, palladium, platinum, silver, tantalum, molybdenum carbide, and tungsten carbide. It is preferable that the material of the first heater element 231 includes both the above metals and a ceramic material. Examples of ceramic materials include aluminum oxide (Al2O3), yttrium oxide (Y2O3), and yttrium aluminum garnet (YAG_Y3Al5O 12Examples include aluminum nitride (AlN), silicon carbide (SiC), etc. Preferably, the ceramic material contained in the first heater element 231 is the same as the components of the ceramic dielectric substrate 100. If the first heater element 231 is separate from the ceramic dielectric substrate 100, examples of materials for the first heater element 231 include metals containing at least one of stainless steel, titanium, chromium, nickel, copper, aluminum, Inconel®, molybdenum, tungsten, palladium, platinum, silver, tantalum, molybdenum carbide, and tungsten carbide. The thickness (length in the Z direction) of the first heater element 231 is, for example, about 0.01 mm or more and 0.20 mm or less. The material and thickness of the second heater element 232 are the same as the material and thickness of the first heater element 231. For example, when the second heater element 232 is provided inside the ceramic dielectric substrate 100, the material of the second heater element 232 may be the same as the material of the first heater element 231 when the first heater element 231 is provided inside the ceramic dielectric substrate 100. For example, when the second heater element 232 is provided outside the ceramic dielectric substrate 100, the material of the second heater element 232 may be the same as the material of the first heater element 231 when the first heater element 231 is provided outside the ceramic dielectric substrate 100. The material and thickness of the second heater element 232 may differ from those of the first heater element 231. The first heater element 231 and the second heater element 232 are electrically connected to the bypass layer 250, for example. On the other hand, the first heater element 231 and the second heater element 232 are electrically insulated from the ceramic dielectric substrate 100.

[0079] The first heater element 231 and the second heater element 232 each generate heat when current flows through them. By generating heat, the first heater element 231 and the second heater element 232 heat the ceramic dielectric substrate 100. The first heater element 231 and the second heater element 232, for example, heat the object W to be processed via the ceramic dielectric substrate 100, thereby making the temperature distribution in the plane of the object W uniform. Alternatively, the first heater element 231 and the second heater element 232 can, for example, intentionally create a temperature difference in the plane of the object W by heating the object W via the ceramic dielectric substrate 100.

[0080] The bypass layer 250 is, for example, plate-shaped and conductive. The bypass layer 250 is electrically connected to, for example, the first heater element 231 and the second heater element 232. The bypass layer 250 is the power supply path for the first heater element 231 and the second heater element 232. On the other hand, the bypass layer 250 is electrically insulated from, for example, the ceramic dielectric substrate 100 by an insulating layer.

[0081] The bypass layer 250 has a plurality of bypass sections 251. For example, two bypass sections 251 are electrically connected to one main zone 600, and two bypass sections 251 are electrically connected to one subzone 700. The two bypass sections 251 correspond to the current inflow side (positive voltage side) and the current outflow side (negative voltage side). In this case, the number of bypass sections 251 is equal to or less than twice the sum of the number of main zones 600 and the number of subzones 700. However, the number of bypass sections 251 is not limited to the above. One bypass section 251 may be electrically connected to multiple main zones 600 or multiple subzones 700.

[0082] The thickness (length in the Z direction) of the bypass layer 250 is, for example, approximately 0.03 mm or more and 0.30 mm or less. The thickness of the bypass layer 250 is greater than the thickness of the first insulating layer 220. The thickness of the bypass layer 250 is greater than the thickness of the second insulating layer 240. The thickness of the bypass layer 250 is greater than the thickness of the third insulating layer 245. The thickness of the bypass layer 250 is greater than the thickness of the fourth insulating layer 260.

[0083] For example, when the bypass layer 250 is provided outside the ceramic dielectric substrate 100, the material of the bypass layer 250 may include metals containing at least one of stainless steel, titanium, chromium, nickel, copper, aluminum, Inconel®, molybdenum, tungsten, palladium, platinum, silver, tantalum, molybdenum carbide, and tungsten carbide. For example, when the heater section 200 (bypass layer 250, first heater element 231, and second heater element 232) is embedded in the ceramic dielectric substrate 100, the material of the bypass layer 250 is the same as the material of the first heater element 231 and the second heater element 232. On the other hand, the thickness of the bypass layer 250 is greater than the thickness of the first heater element 231 and greater than the thickness of the second heater element 232. Therefore, the electrical resistance of the bypass layer 250 is lower than the electrical resistance of the first heater element 231 and lower than the electrical resistance of the second heater element 232. This makes it possible to suppress the heat generation of the bypass layer 250, even when the material of the bypass layer 250 is the same as that of the first heater element 231 and the second heater element 232. In other words, it is possible to reduce the electrical resistance of the bypass layer 250 and reduce the amount of heat generated by the bypass layer 250.

[0084] Furthermore, the means of suppressing the electrical resistance of the bypass layer 250 and the amount of heat generated by the bypass layer 250 may be achieved not by the thickness of the bypass layer 250, but by using a material with a relatively low volume resistivity. In other words, the material of the bypass layer 250 may be different from the material of the first heater element 231 and the second heater element 232. Examples of materials for the bypass layer 250 include metals containing at least one of stainless steel, titanium, chromium, nickel, copper, aluminum, Inconel®, molybdenum, tungsten, palladium, platinum, silver, tantalum, molybdenum carbide, and tungsten carbide.

[0085] For example, when the bypass layer 250 is provided inside the ceramic dielectric substrate 100, the material of the bypass layer 250 is the same as the material of the first heater element 231 when the first heater element 231 is provided inside the ceramic dielectric substrate 100. For example, when the bypass layer 250 is provided outside the ceramic dielectric substrate 100, the material of the bypass layer 250 is the same as the material of the first heater element 231 when the first heater element 231 is provided outside the ceramic dielectric substrate 100.

[0086] The heater unit 200 has a plurality of power supply terminals 280. The power supply terminals 280 are electrically connected to the bypass layer 250. When the heater unit 200 is built into the ceramic dielectric substrate 100, the power supply terminals 280 are provided extending from the heater unit 200 toward the base plate 300. The power supply terminals 280 supply power supplied from outside the electrostatic chuck 10 to the first heater element 231 and the second heater element 232 via the bypass layer 250. The power supply terminals 280 may, for example, be directly connected to the first heater element 231 and the second heater element 232. This makes it possible to omit the bypass layer 250. The shape of the power supply terminals 280 is not particularly limited, and the power supply terminals 280 may be any conductive part that is electrically connected directly or indirectly to at least one of the first heater element 231 and the second heater element 232.

[0087] On the other hand, if the first heater element 231 and / or the second heater element 232 have a large number of zones, for example, 20 or more, or 50 or more, or 100 or more, it may be difficult to arrange the power supply terminals 280 corresponding to each zone. By providing a bypass layer 250, the degree of freedom in arranging the power supply terminals 280 is improved compared to when they are arranged for each zone.

[0088] For example, one power supply terminal 280 is electrically connected to one bypass section 251. For example, the number of power supply terminals 280 is the same as the number of bypass sections 251.

[0089] The first heater element 231 is electrically connected to the bypass layer 250 in the first sub-power supply section 231a and the second sub-power supply section 231b.

[0090] The multiple power supply terminals 280 include multiple sub-power supply terminals 281 (first power supply terminals) for supplying power to multiple subzones 700. For example, two sub-power supply terminals 281 are electrically connected to one subzone 700 via a bypass layer 250. One of the two sub-power supply terminals 281 is electrically connected to a first sub-power supply unit 231a included in one subzone 700, and the other of the two sub-power supply terminals 281 is electrically connected to a second sub-power supply unit 231b included in one subzone 700.

[0091] External current flows from one of the two sub-power supply terminals 281 through the bypass section 251 into one sub-zone 700 (from the first sub-power supply section 231a through the sub-heater line 231c to the second sub-power supply section 231b). The current that has flowed through this sub-zone 700 flows to the outside through another bypass section 251 and the other sub-power supply terminal 281 of the two sub-power supply terminals 281.

[0092] Thus, one of the pair of first power supply units (first sub-power supply unit 231a and second sub-power supply unit 231b) contained in one sub-zone 700 is electrically connected to one of the multiple sub-power supply terminals 281. In other words, each of the pair of first power supply units is electrically connected to each of two of the multiple sub-power supply terminals 281. Each of the multiple first power supply units is electrically connected to each of the multiple sub-power supply terminals 281. For example, the number of multiple sub-power supply terminals 281 is greater than or equal to the number of sub-zones 700. As an example, the number of multiple sub-power supply terminals 281 is twice the number of sub-zones 700.

[0093] However, one sub-power supply terminal 281 may be electrically connected to multiple first power supply units belonging to different subzones 700 via a bypass layer 250. In this case, the number of sub-power supply terminals 281 may be no more than twice the number of subzones 700.

[0094] The second heater element 232 is electrically connected to the bypass layer 250 in the first main power supply section 232a and the second main power supply section 232b.

[0095] The multiple power supply terminals 280 include multiple main power supply terminals 282 (second power supply terminals) for supplying power to multiple main zones 600. For example, two main power supply terminals 282 are electrically connected to one main zone 600 via a bypass layer 250. One of the two main power supply terminals 282 is electrically connected to a first main power supply unit 232a included in one main zone 600, and the other of the two main power supply terminals 282 is electrically connected to a second main power supply unit 232b included in one main zone 600.

[0096] External current flows from one of the two main power supply terminals 282 through the bypass section 251 into one main zone 600 (from the first main power supply section 232a through the main heater line 232c to the second main power supply section 232b). The current that has flowed through this main zone 600 flows out to the outside through another bypass section 251 and the other main power supply terminal 282 of the two main power supply terminals 282.

[0097] Thus, one of the pair of second power supply units (first main power supply unit 232a and second main power supply unit 232b) included in one main zone 600 is electrically connected to one of the multiple main power supply terminals 282. In other words, each of the pair of second power supply units is electrically connected to each of two of the multiple main power supply terminals 282. Each of the multiple second power supply units is electrically connected to each of the multiple main power supply terminals 282. For example, the number of multiple main power supply terminals 282 is less than or equal to the number of main zones 600, and as an example, it is twice the number of main zones 600.

[0098] However, one main power supply terminal 282 may be electrically connected to multiple second power supply units belonging to different main zones 600 via a bypass layer 250. In this case, the number of multiple main power supply terminals 282 may be no more than twice the number of main zones 600.

[0099] For example, the current flowing through the first heater element 231 and the current flowing through the second heater element 232 are controlled separately. In this example, the bypass section 251 connected to the first heater element 231 (first sub-power supply section 231a and second sub-power supply section 231b) and the bypass section 251 connected to the second heater element 232 (first main power supply section 232a and second main power supply section 232b) are different from each other. The bypass section 251 connected to the first heater element 231 (first sub-power supply section 231a and second sub-power supply section 231b) and the bypass section 251 connected to the second heater element 232 (first main power supply section 232a and second main power supply section 232b) may be the same from each other.

[0100] The first heater element 231 generates less heat than the second heater element 232. In other words, the first heater element 231 is a low-power sub-heater, and the second heater element 232 is a high-power main heater.

[0101] In this way, the first heater element 231 generates less heat than the second heater element 232, thereby suppressing temperature unevenness within the surface of the object W being processed, which is caused by the pattern of the second heater element 232. Therefore, the uniformity of the temperature distribution within the surface of the object W being processed can be improved.

[0102] The volume resistivity of the first heater element 231 is higher than, for example, the volume resistivity of the second heater element 232. The volume resistivity of the first heater element 231 is the volume resistivity of the sub-heater line 231c. In other words, the volume resistivity of the first heater element 231 is the volume resistivity between the first sub-power supply unit 231a and the second sub-power supply unit 231b. Similarly, the volume resistivity of the second heater element 232 is the volume resistivity of the main heater line 232c. In other words, the volume resistivity of the second heater element 232 is the volume resistivity between the first main power supply unit 232a and the second main power supply unit 232b.

[0103] In this way, by making the volume resistivity of the first heater element 231 higher than that of the second heater element 232, the output (heat generation, power consumption) of the first heater element 231 can be made lower than the output (heat generation, power consumption) of the second heater element 232. As a result, the temperature unevenness within the surface of the object being processed, caused by the pattern of the second heater element 232, can be suppressed by the first heater element 231. Therefore, the uniformity of the temperature distribution within the surface of the object being processed can be improved.

[0104] The area around the power supply terminal 280 is prone to becoming a temperature singularity (a point where the temperature differs relatively significantly from the surrounding area). In contrast, the provision of the bypass layer 250 allows for greater flexibility in the placement of the power supply terminal 280. For example, the power supply terminal 280, which is prone to becoming a temperature singularity, can be dispersed, making it easier for heat to diffuse around the singularity. This improves the uniformity of the in-plane temperature distribution of the object W being processed.

[0105] The provision of the bypass layer 250 allows for a configuration in which the power supply terminal 280, which has a large heat capacity, is not directly connected to the first heater element 231 and the second heater element 232. This improves the uniformity of the in-plane temperature distribution of the object W being processed. Furthermore, the provision of the bypass layer 250 eliminates the need to directly connect the power supply terminal 280 to the relatively thin first heater element 231 and the second heater element 232. This improves the reliability of the heater unit 200.

[0106] As mentioned above, the power supply terminal 280 is provided extending from the heater unit 200 toward the base plate 300. Power can be supplied to the power supply terminal 280 from the lower surface 303 of the base plate 300 (see Figures 2(a) and 2(b)) via a component called a socket or the like. This allows for heater wiring while preventing the power supply terminal 280 from being exposed inside the chamber where the electrostatic chuck 10 is installed.

[0107] In this example, the first heater element 231 is located above the second heater element 232. In other words, the first heater element 231 is located between the second heater element 232 and the first main surface 101. The positions of the first heater element 231 and the second heater element 232 may be reversed. That is, the second heater element 232 may be located above the first heater element 231. In other words, the second heater element 232 may be located between the first main surface 101 and the first heater element 231. From the viewpoint of temperature control, it is preferable that the first heater element 231 is located above the second heater element 232.

[0108] When the first heater element 231 is positioned above the second heater element 232, the distance between the first heater element 231 and the object W being processed is shorter than the distance between the second heater element 232 and the object W being processed. Because the first heater element 231 is relatively close to the object W being processed, it becomes easier to control the temperature of the object W using the first heater element 231. In other words, the first heater element 231 can more easily suppress temperature unevenness within the surface of the object W caused by the pattern of the second heater element 232. Therefore, the uniformity of the temperature distribution within the surface of the object W can be improved.

[0109] On the other hand, when the second heater element 232 is located above the first heater element 231, the high-output second heater element 232 is relatively close to the object W being processed. This improves the temperature responsiveness (heating rate and cooling rate) of the object W being processed.

[0110] In this example, the second heater element 232 is located between the bypass layer 250 and the first heater element 231 in the Z direction. In other words, the bypass layer 250 is located below the first heater element 231 and the second heater element 232.

[0111] In this way, by providing the second heater element 232 between the bypass layer 250 and the first heater element 231 in the Z direction, the first heater element 231 and the second heater element 232 can be arranged on one side of the bypass layer 250. This allows the power supply terminal 280 to be connected to the bypass layer 250 from the opposite side from the first heater element 231 and the second heater element 232. Therefore, there is no need to provide holes in the first heater element 231 and the second heater element 232 for the power supply terminal 280 to pass through, the temperature singularities on the heater pattern can be reduced, and the uniformity of the in-plane temperature distribution of the first heater element 231 and the second heater element 232 can be improved.

[0112] The bypass layer 250 may be located above the first heater element 231 and the second heater element 232. Alternatively, the bypass layer 250 may be located between the first heater element 231 and the second heater element 232.

[0113] Furthermore, the number of heater elements in the heater unit 200 is not limited to "2". In other words, the heater unit 200 may have additional heater elements provided in layers different from the first heater element 231 and the second heater element 232.

[0114] Figures 9 to 11 are schematic plan views showing a portion of the base plate and heater section according to the embodiment. Figure 9 shows the communication passage 301, multiple sub-power supply terminals 281, and multiple sub-zones 700 of the base plate 300 projected onto a plane perpendicular to the Z direction. Figure 10 shows the communication passage 301, multiple main power supply terminals 282, and multiple main zones 600 of the base plate 300 projected onto a plane perpendicular to the Z direction. Figure 11 is a projection of the communication passage 301, multiple sub-power supply terminals 281, and multiple main power supply terminals 282 of the base plate 300 onto a plane perpendicular to the Z direction.

[0115] The planar shape of the base plate 300 is, for example, circular. Note that the term "circular" includes not only a perfect circle but also an approximate circle. One end 301c of the connecting passage 301 is located near the center 300c of the planar shape of the base plate 300. The other end 301d of the connecting passage 301 is located on the outer periphery of the planar shape of the base plate 300. When viewed along the stacking direction, the connecting passage 301 is spiral-shaped, connecting the one end 301c and the other end 301d. For example, refrigerant flows into the connecting passage 301 from one end 301c, flows through the spiral-shaped connecting passage 301, and flows out of the connecting passage 301 from the other end 301d.

[0116] For example, the connecting passage 301 is a spiral drawn in a single stroke. That is, when viewed along the stacking direction, the connecting passage 301 has a shape that revolves around the center 300c in the circumferential direction and moves away from the center 300c. However, a part of the "spiral shape" may extend toward the center 300c. A part of the "spiral shape" may meander. A part of the "spiral shape" may extend in a straight line.

[0117] In this example, as shown in Figure 9, one subzone 700 overlaps in the Z direction with two sub-power supply terminals 281 that supply power to that subzone 700. In this example, as shown in Figure 10, one main zone 600 overlaps with two main power supply terminals 282 that supply power to that main zone 600 in the Z direction.

[0118] Note that in plan views such as Figure 11, some of the main power supply terminals 282 are shown overlapping with some of the sub-power supply terminals 281. However, the main power supply terminals 282 do not need to overlap with the sub-power supply terminals 281. The size of each terminal may be adjusted as appropriate.

[0119] Figures 12 and 13 are schematic plan views showing a part of the heater section according to the embodiment. Figure 12 shows a projection of the multiple sub-power supply terminals 281 and the multiple sub-zones 700 onto a plane perpendicular to the Z direction. Figure 13 is a projection of the multiple sub-power supply terminals 281, multiple main power supply terminals 282, multiple sub-zones 700, and multiple main zones 600 onto a plane perpendicular to the Z direction.

[0120] The multiple sub-power supply terminals 281 include a first annular portion 281A, a second annular portion 282B, a third annular portion 283C, and a fourth annular portion 282D. Each of the first to fourth annular portions 281A to 281D is a group of multiple sub-power supply terminals 281.

[0121] The first annular portion 281A includes some of the sub-power supply terminals 281 of the plurality of sub-power supply terminals 281. These sub-power supply terminals 281 included in the first annular portion 281A are arranged on the first virtual circle IC1 in a plan view. That is, some of the sub-power supply terminals 281 included in the first annular portion 281A overlap with some of the first virtual circle IC1 in the Z direction. The number of these sub-power supply terminals 281 included in the first annular portion 281A is at least 7, and in this example, it is 16. The second annular portion 281B includes a subset of sub-power supply terminals 281 that are different from those included in the first annular portion 281A. These subset of sub-power supply terminals 281 included in the second annular portion 281B are arranged on the second virtual circle IC2 in a plan view. That is, a subset of the sub-power supply terminals 281 included in the second annular portion 281B overlaps with a subset of the second virtual circle IC2 in the Z direction. The number of these subset of sub-power supply terminals 281 included in the second annular portion 281B is at least 7, and in this example, it is 12. The third annular portion 281C includes a subset of sub-power supply terminals 281 that are separate from the sub-power supply terminals 281 included in the first annular portion 281A and the second annular portion 281B. These subset of sub-power supply terminals 281 included in the third annular portion 281C are arranged on the third virtual circle IC3 in a plan view. That is, a subset of the sub-power supply terminals 281 included in the third annular portion 281C overlaps with a subset of the third virtual circle IC3 in the Z direction. The number of these subset of sub-power supply terminals 281 included in the third annular portion 281C is at least 7, and in this example, it is 16. The fourth annular portion 281D includes a subset of sub-power supply terminals 281 that are separate from those included in the first annular portion 281A, the second annular portion 281B, and the third annular portion 281C. These subset of sub-power supply terminals 281 included in the fourth annular portion 281D are arranged on the fourth virtual circle IC4 in a plan view. That is, a subset of the sub-power supply terminals 281 included in the fourth annular portion 281D overlaps with a subset of the fourth virtual circle IC4 in the Z direction. The number of these subset of sub-power supply terminals 281 included in the fourth annular portion 281D is at least 7, and in this example, it is 16.

[0122] In a plan view, the second virtual circle IC2 is located inside the first virtual circle IC1, the third virtual circle IC3 is located inside the second virtual circle IC2, the fourth virtual circle IC4 is located inside the third virtual circle IC3, and the center CT1 of the first heater element 231 is located inside the fourth virtual circle IC4.

[0123] In a plan view, the second annular portion 281B is located inside the first annular portion 281A. That is, the distance between the sub-power supply terminal 281 included in the second annular portion 281B and the center CT1 is shorter than the distance between the sub-power supply terminal 281 included in the first annular portion 281A and the center CT1. In a plan view, the third annular portion 281C is located inside the second annular portion 281B. That is, the distance between the sub-power supply terminal 281 included in the third annular portion 281C and the center CT1 is shorter than the distance between the sub-power supply terminal 281 included in the second annular portion 281B and the center CT1. In a plan view, the fourth annular portion 281D is located inside the third annular portion 281C. That is, the distance between the sub-power supply terminal 281 included in the fourth annular portion 281D and the center CT1 is shorter than the distance between the sub-power supply terminal 281 included in the third annular portion 281C and the center CT1.

[0124] In this example, the first virtual circle IC1 overlaps with the fifth region 705 in the Z direction. For example, the sub-power supply terminal 281 included in the first annular portion 281A is electrically connected to the sub-zone 700 included in the fifth region 705 (first annular zone region Z11), and supplies power to the sub-zone 700 included in the fifth region 705. In this example, the second virtual circle IC2 overlaps with the fourth region 704 in the Z direction. For example, the sub-power supply terminal 281 included in the second annular portion 281B is electrically connected to the subzone 700 included in the fourth region 704 (second annular zone region Z12), and supplies power to the subzone 700 included in the fourth region 704. In this example, the third virtual circle IC3 overlaps with the third region 703 in the Z direction. For example, the sub-power supply terminal 281 included in the third annular portion 281C is electrically connected to the subzone 700 included in the third region 703 (third annular zone region Z13), and supplies power to the subzone 700 included in the third region 703. In this example, the fourth virtual circle IC4 overlaps with the second region 702 in the Z direction. For example, the sub-power supply terminal 281 included in the fourth annular portion 281D is electrically connected to the sub-zone 700 included in the second region 702 (fourth annular zone region Z14), and supplies power to the sub-zone 700 included in the second region 702.

[0125] As shown in Figure 11, the connecting passage 301 includes a first circulating section 31, a second circulating section 32, and a third circulating section 33. Each of the first circulating section 31, the second circulating section 32, and the third circulating section 33 is a circular (approximately circular) flow path in plan view. Here, "circular (approximately circular)" refers not to a closed ring, but to a part of a spiral shape.

[0126] The first circular portion 31, when viewed along the Z direction (projected onto the XY plane), is located between the first virtual circle IC1 (first annular portion 281A) and the second virtual circle IC2 (second annular portion 281B). When viewed along the Z direction, the first circular portion 31 surrounds the second virtual circle IC2 (second annular portion 281B). In other words, the first circular portion 31 makes approximately one full rotation around the second virtual circle IC2 (second annular portion 281B) (for example, about 300-340°). The first circular portion 31 may make more than one rotation around the second virtual circle IC2 (for example, two to three rotations). The second circular portion 32 is located between the second virtual circle IC2 (second annular portion 281B) and the third virtual circle IC3 (third annular portion 281C) when viewed along the Z direction. The second circular portion 32 surrounds the third virtual circle IC3 (third annular portion 281C) when viewed along the Z direction. In other words, the second circular portion 32 makes approximately one full rotation around the third virtual circle IC3 (third annular portion 281C) (for example, about 300-340°). The second circular portion 32 may make one or more rotations around the third virtual circle IC3 (for example, two to three rotations). The third circular portion 33 is located between the third virtual circle IC3 (third annular portion 281C) and the fourth virtual circle IC4 (fourth annular portion 281D) when viewed along the Z direction. The third circular portion 33 surrounds the fourth virtual circle IC4 (fourth annular portion 281D) when viewed along the Z direction. In other words, the third circular portion 33 makes approximately one full rotation (for example, about 300-340°) around the fourth virtual circle IC4 (fourth annular portion 281D). The third circular portion 33 may make one or more rotations (for example, two or three rotations) around the fourth virtual circle IC4.

[0127] In this example, the connecting passage 301 extends in the circumferential direction Dc while meandering in the radial direction Dr at its spiral outer circumference. Therefore, the first circumferential portion 31 extends in the circumferential direction Dc while meandering. The first circumferential portion 31, the second circumferential portion 32, and the third circumferential portion 33 may or may not meander.

[0128] As explained above, the temperature of the object to be processed is controlled by heating by the heater unit 200 and cooling by the refrigerant flowing through the communication passage 301. In addition, heat input may occur to the object to be processed W from sources such as plasma. As described above with respect to Figure 2, the base plate 300 is provided with terminal holes 300p corresponding to the position of the power supply terminal 280 (or wiring connected to the power supply terminal 280) in order to accommodate the power supply terminal 280. The communication passage 301 (refrigerant flow path) of the base plate 300 is arranged to avoid these terminal holes 300p. In other words, there is no refrigerant flow path in the area where the terminal holes 300p are provided. Therefore, the area of ​​the mounting surface of the ceramic dielectric substrate 100 located above the terminal holes 300p is difficult to cool and may become a hot spot with a higher temperature compared to other areas. For example, if the power supply terminals 280 are randomly arranged in the plane, hot spots will be randomly arranged, resulting in variations in hot / cool temperatures (variations in temperature distribution) in the circumferential direction. As a result, the uniformity of the temperature distribution within the plane of the object W being processed may decrease. For example, depending on the arrangement of the power supply terminals 280, the variation in the plasma distribution may increase.

[0129] In contrast, in this embodiment, more than 20 subzones 700 are provided, and the multiple sub-power supply terminals 281 include a first annular portion 281A and a second annular portion 281B, and the first circumferential portion 31 of the communication passage 301 is positioned between the first annular portion 281A and the second annular portion 281B in a plan view. This suppresses temperature unevenness in the radial and circumferential directions caused by the position of the sub-power supply terminals 281, and improves the uniformity of the in-plane temperature distribution of the object to be processed. For example, a portion of the temperature unevenness (e.g., hot spots) formed by the first annular portion 281A and the second annular portion 281B is offset by a portion of the temperature unevenness (e.g., cool spots) formed by the first circumferential portion 31. As a result, the temperature distribution can be made nearly uniform, and adverse effects on the plasma distribution can be reduced.

[0130] For example, let N1 be the number of subzones 700 included in the first annular zone region Z11 (fifth region 705). The number of sub-power supply terminals 281 included in the first annular portion 281A is greater than 2 × N1 × 0.6 and less than or equal to 2 × N1. As a result, more than 60% of the sub-power supply terminals 281 that supply power to multiple subzones 700 included in the first annular zone region Z11 are included in the first annular portion 281A. This further improves the uniformity of the temperature distribution in the plane. In this example, N1 is 8, and the number of sub-power supply terminals 281 included in the first annular portion 281A is between 10 and 16.

[0131] For example, let N2 be the number of subzones 700 included in the second annular zone region Z12 (fourth region 704). The number of sub-power supply terminals 281 included in the second annular portion 281B is greater than 2 × N2 × 0.6 and less than or equal to 2 × N2. For example, let N3 be the number of subzones 700 included in the third annular zone region Z13 (third region 703). The number of sub-power supply terminals 281 included in the third annular portion 281C is greater than 2 × N3 × 0.6 and less than or equal to 2 × N3. For example, let N4 be the number of subzones 700 included in the fourth annular zone region Z14 (second region 702). The number of sub-power supply terminals 281 included in the fourth annular portion 281D is greater than 2 × N4 × 0.6 and less than or equal to 2 × N4.

[0132] Furthermore, at least a portion of the multiple main power supply terminals 282 overlap with at least one of the first virtual circle IC1 and the second virtual circle IC2 when viewed along the Z direction. This suppresses temperature unevenness caused by the position of the main power supply terminals 282 and improves the uniformity of the temperature distribution in the plane. For example, a portion of the temperature distribution formed by the main power supply terminals 282 (e.g., hot spots) is canceled out by a portion of the temperature distribution formed by the first circular portion 31 (e.g., cool spots). Specifically, as shown in Figure 11, the two main power supply terminals 282 supplying power to the main zone 603 overlap with the first virtual circle IC1 in the Z direction. The two main power supply terminals 282 supplying power to the main zone 602 overlap with the third virtual circle IC3 in the Z direction. The two main power supply terminals 282 supplying power to the main zone 601 overlap with the fourth virtual circle IC4 in the Z direction.

[0133] Furthermore, as mentioned above, the number of subzones 700 is greater than the number of main zones 600. Because the number of subzones 700 is relatively large, for example, the number of sub-power supply terminals 281 is greater than the number of main power supply terminals 282. In this case, the effect of temperature unevenness caused by the sub-power supply terminals 281 may be greater than the effect of temperature unevenness caused by the main power supply terminals 282. To address this, the sub-power supply terminal 281 includes a first annular portion 281A and a second annular portion 281B, and the first circumferential portion 31 of the refrigerant flow path is positioned between the first annular portion 281A and the second annular portion 281B in a plan view. This suppresses temperature unevenness in the radial and circumferential directions caused by the position of the sub-power supply terminal 281, and further improves the uniformity of the temperature distribution in the plane.

[0134] Multiple terminal holes 300p are provided in the base plate 300 at positions corresponding to the power supply terminals 280, penetrating from the upper surface 302 to the lower surface 303 of the base plate 300. In other words, no connecting passage 301 is provided in the areas where terminal holes 300p are provided. Therefore, the temperature of the base plate 300 is higher in the areas where terminal holes 300p are provided compared to the areas where connecting passage 301 is provided. By arranging the first circular portion surrounding the second annular portion between the first annular portion and the second annular portion, the uniformity of the temperature distribution within the plane can be improved.

[0135] Figure 14 is a schematic plan view showing a part of the heater section according to the embodiment. Figure 14 shows the multiple subzones 700 and the first to fourth virtual circles IC1 to IC4 projected onto a plane perpendicular to the Z direction. As shown in Figure 14, the zone center CZ11 of the first annular zone region Z11, the zone center CZ12 of the second annular zone region Z12, the zone center CZ13 of the third annular zone region Z13, and the zone center CZ14 of the fourth annular zone region Z14 all coincide with the center CT1 of the first heater element 231. Note that the center (zone center) may be the centroid in the planar shape.

[0136] The zone center CZ11 of the first annular zone region Z11 coincides with at least one of the center C1 (first center) of the first virtual circle IC1 and the center C2 (second center) of the second virtual circle IC2. This makes it possible to suppress the bias in the position of the sub-power supply terminal 281 included in at least one of the first annular portion 281A and the second annular portion 281B with respect to the subzone 700 included in the first annular zone region Z11. This makes it possible to further improve the uniformity of the temperature distribution in the plane.

[0137] In the example shown in Figure 14, the center CZ11 of the first annular zone region Z11 coincides with the center C1 of the first virtual circle IC1. In this case, for example, the bias in the position of the sub-power supply terminal 281 included in the first annular portion 281A relative to the sub-zone 700 included in the first annular zone region Z11 can be suppressed. The first annular portion 281A is located outside the second annular portion 281B. Therefore, for example, the uniformity of the temperature distribution on the outer periphery of the mounting surface can be further improved.

[0138] In the example shown in Figure 14, the center C4 of the fourth virtual circle IC4 coincides with the center CT1 of the first heater element 231. The center C2 of the second virtual circle IC2 and the center C3 of the third virtual circle IC3 do not coincide with the center CT1 of the first heater element 231. However, the centers C2 and C3 may each coincide with the center CT1.

[0139] Note that "match" does not necessarily mean an exact match; an approximate match is also acceptable. For example, even slight differences due to variations in process conditions are considered a "match."

[0140] Figures 15 to 17 are schematic plan views showing a modified example of the embodiment, specifically a base plate and a portion of the heater section. Figures 15 to 17 show modified versions of the base plate 300 and heater section 200. These modified versions differ from the above-described example in the shape of the communication passage 301, the arrangement of the sub-power supply terminal 281, and the arrangement of the main power supply terminal 282. Otherwise, the same explanation as the above-described example can be applied to the modified versions.

[0141] Figure 15 is a projection of the connecting passage 301, the multiple sub-power supply terminals 281, and the multiple sub-zones 700 onto a plane perpendicular to the Z direction. Figure 16 is a projection of the connecting passage 301, the multiple main power supply terminals 282, and the multiple main zones 600 onto a plane perpendicular to the Z direction. Figure 17 is a projection of the connecting passage 301, multiple sub-power supply terminals 281, multiple sub-zones 700, multiple main power supply terminals 282, and multiple main zones 600 onto a plane perpendicular to the Z direction.

[0142] As shown in Figures 15 to 17, in this example, the connecting passage 301 extends along the circumferential direction Dc without meandering in the spiral outer periphery.

[0143] Figures 18 and 19 are schematic plan views showing a part of the heater section according to a modified embodiment. Figure 18 is a projection of the multiple sub-power supply terminals 281 and multiple sub-zones 700 shown in Figure 17 onto a plane perpendicular to the Z direction. Figure 19 is a projection of the multiple main power supply terminals 282 and multiple main zones 600 shown in Figure 17 onto a plane perpendicular to the Z direction.

[0144] As shown in Figure 18, in the modified example, the multiple sub-power supply terminals 281 also include a first annular portion 281A, a second annular portion 281B, a third annular portion 281C, and a fourth annular portion 281D. The multiple sub-power supply terminals 281 included in the first annular portion 281A are arranged on the first virtual circle IC1, the multiple sub-power supply terminals 281 included in the second annular portion 281B are arranged on the second virtual circle IC2, the multiple sub-power supply terminals 281 included in the third annular portion 281C are arranged on the third virtual circle IC3, and the multiple sub-power supply terminals 281 included in the fourth annular portion 281D are arranged on the fourth virtual circle IC4. Furthermore, as shown in Figure 15, the connecting passage 301 includes a first circular portion 31, a second circular portion 32, and a third circular portion 33.

[0145] In this example, the first virtual circle IC1, the second virtual circle IC2, and the third virtual circle IC3 are concentric. For example, the center C1 of the first virtual circle IC1, the center C2 of the second virtual circle IC2, and the center C3 of the third virtual circle IC3 each coincide with the center CT1 of the first heater element 231.

[0146] The sub-power supply terminals 281 included in the first annular portion 281A may be evenly distributed in the circumferential direction Dc. That is, the distance LA along the circumferential direction Dc between two adjacent sub-power supply terminals 281 included in the first annular portion 281A in the circumferential direction Dc may be constant. This can further improve the uniformity of the temperature distribution in the circumferential direction Dc.

[0147] Similarly, the sub-power supply terminals 281 included in the second annular portion 281B may be evenly distributed in the circumferential direction Dc. That is, the distance LB along the circumferential direction Dc between two adjacent sub-power supply terminals 281 included in the second annular portion 281B in the circumferential direction Dc may be constant. The sub-power supply terminals 281 included in the third annular portion 281C may be evenly distributed in the circumferential direction Dc. That is, the distance LC along the circumferential direction Dc between two adjacent sub-power supply terminals 281 included in the third annular portion 281C in the circumferential direction Dc may be constant. The sub-power supply terminals 281 included in the fourth annular portion 281D may be evenly distributed in the circumferential direction Dc. That is, the distance LD along the circumferential direction Dc between two adjacent sub-power supply terminals 281 included in the fourth annular portion 281D may be constant. This can further improve the uniformity of the temperature distribution in the circumferential direction Dc.

[0148] Furthermore, "constant" does not necessarily mean completely unchanging; it can also mean approximately constant. For example, even if there are some differences due to variations in process conditions, it is still considered "constant."

[0149] For example, the sub-power supply terminals 281 included in the first annular portion 281A, the sub-power supply terminals 281 included in the second annular portion 281B, the sub-power supply terminals 281 included in the third annular portion 281C, and the sub-power supply terminals 281 included in the fourth annular portion 281D are aligned in the radial direction Dr.

[0150] As shown in Figure 19, in a plan view, the main power supply terminal 282 that supplies power to the main zone 601 may be located on the fourth virtual circle IC4. In a plan view, the main power supply terminal 282 that supplies power to the main zone 602 may be located on the third virtual circle IC3. In a plan view, the main power supply terminal 282 that supplies power to the main zone 601 may be located on the first virtual circle IC1 (or the second virtual circle IC2). This suppresses temperature unevenness caused by the main power supply terminal 282 and further improves the uniformity of the temperature distribution in the plane.

[0151] Figure 20 is a schematic diagram representing a simulation model of the temperature distribution on the surface of the ceramic dielectric substrate of an electrostatic chuck. Simulations were performed for three models with different arrangement patterns of the power supply terminals 280 in a plan view. Each model is provided with three power supply terminals 280. The upper part of Figure 20 shows the arrangement of the power supply terminals 280 in a plan view when viewed from above. The lower part of Figure 20 shows the arrangement of the power supply terminals 280 and the connecting passage 301 in a plan view when viewed from below (back side). The rectangular areas in the middle of Model 2 and Model 3 are enlarged representations of the area around the circle in the lower part.

[0152] In each model, the connecting passage 301 is spiral-shaped. As shown in Figures 9 and 15 above, the "spiral shape" may include portions that extend in a straight line or portions that extend in a circular arc with a constant diameter in a plan view, as long as the whole is spiral-shaped. That is, in the example of Figure 20, the path that goes from one end of the connecting passage 301 to the other has a shape that moves away from the center while spiraling in the direction of rotation. As already mentioned, in the embodiment, the connecting passage may include a meandering portion. That is, the connecting passage may include a portion that extends away from the center along the direction of rotation and a portion that extends towards the center along the direction of rotation. The direction of rotation is either clockwise or counterclockwise.

[0153] In Model 1 (distributed type), three power supply terminals 280 are evenly distributed on a single virtual circular IC. That is, the three power supply terminals are located on the same virtual circular IC and are spaced approximately 120° apart from the center Pc of the virtual circular IC. In other words, the angle θ between adjacent power supply terminals 280, as seen from the center Pc, is 120°.

[0154] The connecting passage 301 has a circumferential portion 33a and a circumferential portion 32a. In a plan view, the arc-shaped circumferential portion 32a surrounds the arc-shaped circumferential portion 33a. In a plan view, the virtual circle IC surrounds the circumferential portion 33a and is surrounded by the circumferential portion 32a. In other words, the virtual circle IC is located between the circumferential portion 32a and the circumferential portion 33a.

[0155] In Model 2 (radially parallel type), the power supply terminals 280 are arranged in a radial direction Dr and are positioned close to each other. In a plan view, the three power supply terminals 280 are located between the circumferential portion 32a and the circumferential portion 33a. Of the three, the middle power supply terminal 280 is located on the virtual circle IC, while the other two power supply terminals 280 are not located on the virtual circle IC.

[0156] In Model 3 (tangential parallel type), the three power supply terminals 280 are located close to each other on the virtual circular IC. The three power supply terminals 280 are located on the virtual circular IC and are adjacent in the circumferential direction Dc.

[0157] For these Models 1-3, the temperature distribution on the surface of the ceramic dielectric substrate 100 was analyzed when a predetermined amount of heat (watts) was applied from above while a coolant was flowing through the communication passage 301.

[0158] Figure 21 is a schematic plan view showing the simulation results of the temperature distribution on the surface of the ceramic dielectric substrate of the electrostatic chuck. Figures 22(a) and 22(b) are graphs showing the simulation results of the temperature distribution on the surface of the ceramic dielectric substrate of the electrostatic chuck.

[0159] Figure 21 shows the temperature distribution in the plane. Figure 22(a) shows the temperature along a path on a virtual circle IC. This path is a counterclockwise loop starting from point P1 on the virtual circle IC shown in Figure 20. The horizontal axis in Figure 22(a) is the angle obtained by moving counterclockwise from point P on the virtual circle IC, as viewed from the center Pc. Figure 22(b) is an enlarged view of the area enclosed by the dotted line in Figure 22(a).

[0160] The peak temperature in the circumferential direction is lowest in Model 1 among the three models. Thus, in this embodiment, it is preferable to arrange the power supply terminals 280 dispersed on the same circumference. This makes it possible to make the temperature distribution in the plane more uniform, for example.

[0161] For example, it is preferable that multiple power supply terminals 280 on the same circumference be evenly distributed. That is, it is preferable that the angle θ between adjacent power supply terminals 280 on the virtual circle IC, as seen from the center Pc, be a constant predetermined angle. Note that this predetermined angle does not have to be strictly constant and may vary, for example, within a range of about ±10%.

[0162] As described above, according to the embodiment, an electrostatic chuck is provided that can improve the uniformity of the in-plane temperature distribution of the object to be processed.

[0163] Embodiments of the present invention have been described above. However, the present invention is not limited to these descriptions. Modifications made by those skilled in the art to the above-described embodiments are also included within the scope of the present invention, as long as they retain the features of the present invention. For example, the shape, dimensions, material, arrangement, and mounting configuration of each element of the electrostatic chuck are not limited to those exemplified and can be modified as appropriate.

[0164] Furthermore, the elements of each of the embodiments described above can be combined to the extent technically possible, and these combinations are also included within the scope of the present invention insofar as they include the features of the present invention. [Explanation of Symbols]

[0165] 10 Electrostatic chuck, 20 Power supply, 21 Conductive part, 31-33 First to third circular parts, 100 Ceramic dielectric substrate, 101, 102 First and second main surfaces, 111 Electrode layer, 113 Protrusion, 115 Groove, 200 Heater part, 220 First insulating layer, 231 First heater element, 231a First sub-power supply part, 231b Second sub-power supply part, 231c Sub-heater line, 231e Outer edge, 232 Second heater element, 232a First main power supply part, 232b Second main power supply part, 232c Main heater line, 232e Outer edge, 240 Second insulating layer, 245 Third insulating layer, 250 Bypass layer, 251 Bypass part, 260 Fourth insulating layer, 280 Power supply terminal, 281 Sub-power supply terminal, 281A~281D First to fourth ring sections, 282 Main power supply terminal, 300 Base plate, 300c Center, 300p Terminal hole, 301 Connecting passage, 301c One end, 301d Other end, 302 Top surface, 303 Bottom surface, 321 Induction path, 600, 601~603 Main zone, 700 Sub-zone, 701 First region, 701β Outer edge, 701a Sub-zone, 702 Second region, 702α Inner edge, 702β Outer edge, 702a~702h Sub-zone, 703 Third region, 703α Inner edge, 703β Outer edge, 703a~703h Subzone, 704 4th Region, 704α Inner Peripheral Edge, 704β Outer Peripheral Edge, 704a~704h Subzone, 705 5th Region, 705α Inner Peripheral Edge, 705a~705h Subzone, B2 Region, C1~C4 Center, CT1, CT2 Center, CZ11~CZ14 Zone Center, Dc Circumferential Direction, Dr Radial Direction, IC Virtual Circle, IC1~IC4 1st~4th Virtual Circles, LA~LD Distance, LM1~LM3 Width, LS1~LS5 Width, P1 Point, Pc Center, W Object to be Processed, Z11~Z14 1st~4th Annular Zone Region, θ Angle

Claims

1. A ceramic dielectric substrate on which the object to be processed is placed, A base plate that supports the ceramic dielectric substrate and has an upper surface on the side of the ceramic dielectric substrate and a lower surface opposite to the upper surface, wherein the base plate includes a spiral-shaped passage provided between the upper surface and the lower surface through which a refrigerant can pass, A first heater element comprising 20 or more first zones arranged radially and circumferentially, Multiple first power supply terminals for supplying power to the multiple first zones, Equipped with, Each of the plurality of first zones includes a first heater line that generates heat when an electric current flows through it, and a pair of first power supply units that supply power to the first heater line. The number of the plurality of first power supply terminals is equal to or greater than the number of the first zones. The pair of first power supply units are electrically connected to the plurality of first power supply terminals, The plurality of first power supply terminals are, A first annular portion including some of the first power supply terminals among the plurality of first power supply terminals, wherein the some power supply terminals included in the first annular portion are arranged on a first virtual circle, and the number of the some first power supply terminals included in the first annular portion is at least 7. A second annular portion located inside the first annular portion, which includes another portion of the plurality of first power supply terminals, wherein the other portion of first power supply terminals included in the second annular portion are arranged on a second virtual circle, and the number of the other portion of first power supply terminals included in the second annular portion is at least 7. Includes, The electrostatic chuck is characterized in that the communication passage includes a first circular portion surrounding the second annular portion, when viewed along the stacking direction of the base plate and the ceramic dielectric substrate, between the first annular portion and the second annular portion.

2. The plurality of first zones include a first annular zone region which includes a portion of the plurality of first zones, The portion of the first zone included in the first annular zone region is arranged in the circumferential direction, The first power supply terminals included in the first annular portion are first power supply terminals that supply power to the first zone included in the first annular zone region, The electrostatic chuck according to claim 1, characterized in that, if N1 is the number of first zones in the first annular zone region, the number of first power supply terminals in the first annular portion is greater than 2 × N1 × 0.

6.

3. The plurality of first zones include a first annular zone region which includes a portion of the plurality of first zones, The portion of the zones included in the first annular zone region are arranged in the circumferential direction, The first power supply terminals included in the first annular portion are first power supply terminals that supply power to the first zone included in the first annular zone region, The electrostatic chuck according to claim 1, characterized in that the zone center of the first annular zone region coincides with at least one of the first center of the first virtual circle and the second center of the second virtual circle.

4. The electrostatic chuck according to claim 3, characterized in that at least one of the above is the first center of the first virtual circle.

5. The electrostatic chuck according to any one of claims 1 to 4, characterized in that some of the first power supply terminals included in the first annular portion are evenly arranged in the circumferential direction.

6. A second heater element comprising at least a plurality of second zones arranged radially, Multiple second power supply terminals for supplying power to the aforementioned multiple second zones, Furthermore, Each of the plurality of second zones includes a second heater line that generates heat when current flows through it, and a pair of second power supply units that supply power to the second heater line. The number of the aforementioned multiple second power supply terminals is equal to or greater than the number of the second zones. The pair of second power supply units are electrically connected to the plurality of second power supply terminals, The electrostatic chuck according to any one of claims 1 to 5, characterized in that, when viewed along the stacking direction, at least a portion of the plurality of second power supply terminals overlaps with at least one of the first virtual circle and the second virtual circle.

7. The electrostatic chuck according to claim 6, characterized in that the number of the plurality of first zones is greater than the number of the plurality of second zones.

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