Ceramic heater

Abstract

Provided is a ceramic heater in which the thermal uniformity of a plate can be improved. The ceramic heater comprises: a plate; and a first heater layer, a plurality of first power supply terminals, an annular second heater layer, a plurality of second power supply terminals, and a plurality of jumper layers that are incorporated into the plate. The plurality of jumper layers are connected to one corresponding second power supply terminal among the plurality of second power supply terminals, and are connected to the second heater layer via a corresponding connecting portion among a plurality of connecting portions provided in the second heater layer. In the plurality of jumper layers, slits are formed that, in a plan view, divide the jumper layer into a plurality of regions including an innermost first region including a first end portion to which the second power supply terminal is connected and an outermost second region including a second end portion to which the connecting portion is connected, the first region extending in a positive direction, and the regions other than the first region extending in the direction opposite to the immediately inner region. The width of each of the plurality of regions is greater than the width of a resistance heating element that forms the second heater layer.

Description

Ceramic heater

[0001] This disclosure relates to a ceramic heater. This application claims priority based on Japanese Patent Application No. 2025-26157 filed on February 20, 2025, and incorporates all the descriptions described in the Japanese patent application.

[0002] In a semiconductor manufacturing apparatus, for example, when performing a film formation or etching process on a wafer, a ceramic heater is used to heat the wafer. A ceramic heater that includes a disc-shaped ceramic plate and a cylindrical ceramic shaft joined to the plate is widely used. The plate incorporates a heater layer formed by a resistance heating element that generates heat by energization. The plate is required to have a uniform heat property with a small temperature difference from the center to the outer periphery in order to uniformly heat the entire wafer. Therefore, a multi-zone ceramic heater that divides the plate into two heating zones, an inner zone on the center side and an outer zone on the outer periphery side, and arranges the heater layer for each heating zone is known. In the multi-zone ceramic heater, the heating temperature is adjusted for each heating zone by individually controlling the current flowing through the first heater layer arranged in the inner zone and the second heater layer arranged in the outer zone.

[0003] In a multi-zone ceramic heater, it is common for a power supply terminal for supplying power to the second heater layer to be built in a position near the center of the plate. Therefore, a jumper layer that conducts the power supply terminal and the second heater layer is built in a position below the first heater layer in the plate. The jumper layer is formed by, for example, a thin strip-shaped conductive member that linearly extends in the radial direction of the plate. However, in a ceramic heater with such a jumper layer built in the plate, heat generation occurs at the location where the jumper layer is arranged due to heat generation caused by the electrical resistance of the jumper layer, so there is a concern that local hot spots and cool spots will occur on the plate. Therefore, there is a concern that the uniform heat property of the plate will deteriorate.

[0004] Therefore, in the ceramic heater described in Patent Document 1, in order to improve the uniform heating of the plate, as shown in Figure 13(A), a first lower heating resistor 103 is arranged over the entire area of ​​the inner zone 101 where the upper heating resistor corresponding to the first heater layer is located, when viewed along the thickness direction of the plate 100. The first lower heating resistor 103 corresponds to a jumper layer that conducts electrical connections between the power supply terminal 106 and the second lower heating resistor 104, which corresponds to the second heater layer located in the outer zone 102.

[0005] Japanese Patent Publication No. 2018-5999

[0006] However, in the ceramic heater described in Patent Document 1, as shown in Figure 13(B), when current is supplied to the first lower heating resistance element 103, the current flows through the shortest path indicated by the arrow between the power supply terminal 106 and the connection portion 105 between the first lower heating resistance element 103 and the second lower heating resistance element 104. As a result, the first lower heating resistance element 103 does not heat uniformly across its entire surface, and localized hot spots and cool spots occur on the plate 100 due to the main heat generation in a part of the first lower heating resistance element 103. Therefore, the uniformity of the heat distribution of the plate 100 may deteriorate.

[0007] One of the objectives of this disclosure is to provide a ceramic heater that can improve the uniformity of heating of a plate.

[0008] A ceramic heater according to this disclosure comprises: a plate having a first main surface for supporting a wafer and a second main surface positioned at a distance from the first main surface in the thickness direction; a first heater layer formed of a resistance heating element embedded in the plate and generating heat when energized; a plurality of first power supply terminals embedded in the plate and connected to the first heater layer so as to be positioned in the center of the plate when viewed along the thickness direction of the plate; an annular second heater layer formed of a resistance heating element that generates heat when energized and is embedded in the plate so as to be positioned outside the first heater layer when viewed along the thickness direction of the plate; a plurality of second power supply terminals embedded in the plate and for supplying power to the second heater layer so as to be positioned in the center of the plate when viewed along the thickness direction of the plate; and a plurality of jumper layers embedded in the plate so as to be positioned on the second main surface side of the first heater layer in the thickness direction of the plate and on the inside of the second heater layer when viewed along the thickness direction of the plate. In a ceramic heater according to this disclosure, the multiple jumper layers are connected to a corresponding second power supply terminal among a plurality of second power supply terminals, and are connected to the second heater layer via a corresponding connection portion among a plurality of connection portions provided on the second heater layer. The multiple jumper layers also have at least one slit formed therein, which divides the jumper layer into a plurality of regions when viewed along the thickness direction of the plate, each region including at least a first region which is the innermost region including the first end to which the second power supply terminal is connected, and a second region which is the outermost region including the second end to which the connection portion is connected, wherein the first region extends in the positive direction in the circumferential direction of the plate, and the regions other than the first region extend in the opposite direction in the circumferential direction of the plate to the region one innermost. Furthermore, the width of each of the plurality of regions is greater than the width of the resistance heating element forming the second heater layer.

[0009] According to the ceramic heater described herein, the uniformity of heating of the plate can be improved.

[0010] Figure 1 is a cross-sectional view showing the schematic structure of a ceramic heater according to one embodiment of the present disclosure. Figure 2 is a perspective view of the first heater layer, the second heater layer, and the jumper layer. Figure 3 is a plan view of the first heater layer, the second heater layer, and the jumper layer. Figure 4 is a plan view of the second heater layer and the jumper layer. Figure 5 is a plan view of the second heater layer. Figure 6 is a plan view of the jumper layer. Figure 7 is a conceptual diagram showing an example where the wiring pattern of the second resistive heating element is a parallel circuit when there are two jumper layers. Figure 8 is a conceptual diagram showing an example where the wiring pattern of the second resistive heating element is a series circuit when there are two jumper layers. Figure 9 is a plan view of a modified jumper layer. Figure 10A is a cross-sectional view showing the schematic structure of the connection portion between the connector and the jumper layer. Figure 10B is a cross-sectional view showing the schematic structure of a modified connection portion between the connector and the jumper layer. Figure 11 is a cross-sectional view of a ceramic heater according to a modified example of the present disclosure. Figures 12(A) and (B) are plan views of modified jumper layers. Figures 13(A) and (B) are cross-sectional views of a conventional ceramic heater.

[0011] [Summary of Embodiments] First, embodiments of ceramic heaters according to this disclosure are listed and described.

[0012] A ceramic heater according to a first aspect of the present disclosure comprises: a plate having a first main surface for supporting a wafer and a second main surface positioned at a distance from the first main surface in the thickness direction; a first heater layer formed of a resistance heating element embedded in the plate and generating heat when an electric current is passed through it; a plurality of first power supply terminals embedded in the plate and connected to the first heater layer so as to be positioned in the center of the plate when viewed along the thickness direction of the plate; an annular second heater layer formed of a resistance heating element that generates heat when an electric current is passed through it and is positioned outside the first heater layer when viewed along the thickness direction of the plate; a plurality of second power supply terminals embedded in the plate and for supplying power to the second heater layer so as to be positioned in the center of the plate when viewed along the thickness direction of the plate; and a plurality of jumper layers embedded in the plate so as to be positioned on the second main surface side of the first heater layer in the thickness direction of the plate and inside the second heater layer when viewed along the thickness direction of the plate. In the ceramic heater according to the first embodiment, the multiple jumper layers are connected to a corresponding second power supply terminal among the multiple second power supply terminals, and are connected to the second heater layer via a corresponding connection part among the multiple connection parts provided on the second heater layer. Furthermore, the multiple jumper layers have at least one slit formed therein, which divides the jumper layer into multiple regions when viewed along the thickness direction of the plate, each region including at least a first region which is the innermost region including the first end to which the second power supply terminal is connected, and a second region which is the outermost region including the second end to which the connection part is connected, wherein the first region extends in the positive direction in the circumferential direction of the plate, and the regions other than the first region extend in the opposite direction in the circumferential direction of the plate to the region one innermost. Furthermore, the width of each of the multiple regions is greater than the width of the resistance heating element forming the second heater layer.

[0013] The multiple jumper layers are configured such that, when viewed along the thickness direction of the plate, the multiple regions are arranged in a zigzag pattern, from the innermost first region including the first end to which the second power supply terminal is connected, to the outermost second region including the second end to which the connection is connected. Therefore, in the multiple jumper layers, when current is supplied to the second heater layer and conduction is made between the second heater layer and the second power supply terminal, the current spreads over a wide area of ​​the jumper layer, causing the jumper layer to heat up uniformly over its entire or nearly entire area. This suppresses the occurrence of localized hot spots and cool spots on the plate due to the heat generated by the jumper layer itself. Furthermore, if the width and area of ​​each region in the jumper layer are large, the resistance of each region in the jumper layer is reduced. This reduces the amount of heat generated in the jumper layer when current is supplied to the second heater layer. Thus, the ceramic heater according to the first embodiment can improve the uniformity of the heat distribution of the plate.

[0014] As a ceramic heater according to a second aspect of the present disclosure, the ceramic heater according to the first aspect described above may be configured such that the width of each of the multiple regions is 2 to 75 times the width of the resistance heating element forming the second heater layer.

[0015] According to the ceramic heater of the second embodiment, the resistance of each region of the jumper layer can be reduced effectively, thereby effectively reducing the amount of heat generated in the jumper layer when current is supplied to the second heater layer. Therefore, the uniformity of the heat distribution of the plate can be improved.

[0016] As a ceramic heater according to a third aspect of this disclosure, the ceramic heater according to the first or second aspect described above may be configured such that the width of the slit is 1.0 mm or more.

[0017] According to the ceramic heater of the third embodiment, by appropriately setting the distance between the jumper layers sandwiching the slit, the amount of heat generated in the jumper layer when power is supplied to the second heater layer can be significantly reduced. Therefore, the uniformity of the heat distribution of the plate can be further improved.

[0018] As a ceramic heater according to the fourth aspect of the present disclosure, a ceramic heater according to any one of the first to third aspects described above may be configured such that a slit is formed in a plurality of jumper layers, dividing the jumper layer into two regions when viewed along the thickness direction of the plate: a first region extending from the first end in the positive direction of the circumferential direction of the plate, and a second region extending to the second end in the negative direction opposite to the positive direction of the circumferential direction of the plate.

[0019] According to the ceramic heater of the fourth embodiment, the width of each region in the jumper layer can be increased, thereby increasing the area of ​​each region in the jumper layer and effectively reducing the resistance of each region. Therefore, the amount of heat generated in the jumper layer when current is supplied to the second heater layer can be effectively reduced, thereby further improving the uniformity of the heat distribution of the plate.

[0020] As a ceramic heater according to the fifth aspect of this disclosure, a ceramic heater according to any one of the first to fourth aspects described above may be configured such that a plurality of connection portions of the second heater layer protrude inward toward the corresponding jumper layer among the plurality of jumper layers and connect with the jumper layer.

[0021] According to the ceramic heater of the fifth embodiment, the second heater layer and the jumper layer can be connected with a simple structure.

[0022] As a ceramic heater according to the sixth aspect of this disclosure, the ceramic heater according to the fifth aspect described above may be configured such that the thickness of the connecting portion connecting the connection portion and the jumper layer is greater than the thickness of the jumper layer and the second heater layer.

[0023] The connection point between the second heater layer and the jumper layer is prone to overheating due to current concentration when the second heater layer is energized. However, according to the ceramic heater of the sixth embodiment, the increased thickness of the connection point reduces its resistance. This reduces the amount of heat generated at the connection point when the second heater layer is energized. As a result, localized hot spots on the plate can be suppressed, and the uniformity of the plate's heating can be improved.

[0024] As a ceramic heater according to the seventh aspect of this disclosure, a ceramic heater according to any one of the first to sixth aspects described above may be configured such that the thickness of the jumper layer is greater than the thickness of the second heater layer.

[0025] According to the ceramic heater of the seventh embodiment, the resistance of the jumper layer is reduced because the thickness of the jumper layer is greater than the thickness of the second heater layer. As a result, the amount of heat generated in the jumper layer when current is supplied to the second heater layer can be reduced effectively. Therefore, the uniformity of the heat distribution of the plate can be improved.

[0026] As a ceramic heater according to the eighth aspect of the present disclosure, a ceramic heater according to any one of the first to seventh aspects described above may be configured such that a plurality of jumper layers are arranged inside the plate at the same height in the thickness direction of the plate, and are separated from each other along the circumferential direction of the plate when viewed along the thickness direction of the plate, and the angle between a first line segment connecting the center of the plate and one end of the slit and a second line segment connecting the center of the plate and the other end of the slit when viewed along the thickness direction of the plate is 1 / 2 × 360° / n (where n is the number of jumper layers) or more.

[0027] According to the ceramic heater of the eighth embodiment, the current can be distributed over a wider area of ​​the jumper layer. This improves the uniform heating of the plate.

[0028] As a ceramic heater according to the ninth aspect of the present disclosure, a ceramic heater according to any one of the first to eighth aspects described above may include an inner zone which is a circular region within a first distance from the center of the plate when viewed along the thickness direction of the plate and in which a first heater layer and a plurality of jumper layers are arranged, and an outer zone which is an annular region within a second distance from the center of the plate and outside the inner zone and in which a second heater layer is arranged, and the ratio of the area of ​​the plurality of jumper layers to the area of ​​the inner zone is 75% or more.

[0029] According to the ceramic heater of the ninth embodiment, since the area of ​​the jumper layer is large, the resistance of the jumper layer is reduced effectively, and the amount of heat generated in the jumper layer when current is supplied to the second heater layer can be reduced effectively. Therefore, the uniformity of heating of the plate can be improved.

[0030] [Specific Examples of Embodiments] Next, specific embodiments of a ceramic heater according to this disclosure will be described with reference to the drawings. In the drawings, identical or corresponding parts are given the same reference numerals.

[0031] <Overview of the Ceramic Heater> Figure 1 is a cross-sectional view showing the schematic structure of a ceramic heater 1 according to one embodiment of the present disclosure. Figure 2 is a perspective view of the first heater layer 3, the second heater layer 4, and a plurality of jumper layers 5, with the first heater layer 3 and the second heater layer 4 shown in schematic structure. Figure 3 is a plan view of the first heater layer 3, the second heater layer 4, and the plurality of jumper layers 5. In the following description, viewing an object along the thickness direction of the plate 2 is referred to as a "plan view". Also, the shape of an object along the thickness direction of the plate 2 is referred to as the "plan view shape".

[0032] The ceramic heater 1 is installed inside the vacuum chamber of a semiconductor manufacturing apparatus as a ceramic stand for supporting the wafer W. The inside of the vacuum chamber is maintained in a vacuum or reduced-pressure atmosphere, and processes such as film deposition (forming a thin film on the wafer W by chemical vapor deposition (CVD)) and etching of the wafer W are performed inside the vacuum chamber. The ceramic heater 1 is used in the semiconductor manufacturing apparatus to heat the wafer W to a desired temperature when performing processes such as film deposition and etching on the wafer W.

[0033] The ceramic heater 1 comprises a plate-shaped ceramic plate 2, a cylindrical ceramic shaft 10, and a first heater layer 3, a second heater layer 4, a plurality of jumper layers 5, a plurality of first power supply terminals 6, and a plurality of second power supply terminals 7 embedded in the plate 2.

[0034] Within the plate 2, for example, the second heater layer 4 is positioned closer to the second main surface 23 (on the second main surface 23 side) than the first heater layer 3, and the multiple jumper layers 5 are positioned at the same height as the second heater layer 4. Note that positions at the same height include positions in the thickness direction of the plate 2 where the height is exactly the same and positions where the height is approximately the same.

[0035] Plate 2 includes an inner zone 20, which is the region within a first distance from the center of plate 2 when viewed along the thickness direction of plate 2, and an outer zone 21, which is an annular region within a second distance (>first distance) from the center of plate 2 and outside the inner zone 20. Here, when viewing plate 2 along the thickness direction, the outer side refers to the outer edge of plate 2, and the inner side refers to the center side of plate 2.

[0036] The inner zone 20 is a region having an outer edge that is similar in shape to the outer edge of the plate 2 in a plan view. The first heater layer 3 is arranged in the inner zone 20 so as to extend over its entire or nearly entire area. Furthermore, multiple jumper layers 5 are arranged in the inner zone 20 so as to extend over its entire or nearly entire area at positions where their height differs from that of the first heater layer 3 in the thickness direction of the plate 2. Note that when we say that the first heater layer 3 and the multiple jumper layers 5 extend over the entire or nearly entire area of ​​the inner zone 20, we mean that the area of ​​the first heater layer 3 and the area of ​​the multiple jumper layers 5 occupy all or most of the area of ​​the region from the center of the plate 2 to the outer edge of the inner zone 20 in a plan view.

[0037] The outer zone 21 is an annular region having an outer edge that is similar in shape to the outer edge of plate 2 in a plan view. The annular second heater layer 4 is arranged in the annular outer zone 21 so as to extend over its entirety or nearly its entirety. When we say that the second heater layer 4 extends over the entire or nearly its entirety in the outer zone 21, we mean that the area of ​​the second heater layer 4 occupies all or most of the area of ​​the region from the outer edge of the inner zone 20 to the outer edge of the outer zone 21 in a plan view.

[0038] The multiple first power supply terminals 6 are terminals for supplying power to the first heater layer 3. In this embodiment, two first power supply terminals 6 are built into the plate 2. The multiple first power supply terminals 6 are built into the plate 2 in a region near the center of the plate 2 in a plan view and are electrically connected to the first heater layer 3. A metal first power supply member 60, for example, which is rod-shaped, is electrically connected to the multiple first power supply terminals 6. Current is supplied to the first heater layer 3 from an external heater power supply via the first power supply member 60 and the first power supply terminals 6. In this disclosure, the region near the center of the plate 2 in a plan view is referred to as the central part of the plate 2.

[0039] The multiple second power supply terminals 7 are terminals for supplying power to the second heater layer 4. In this embodiment, two second power supply terminals 7 are built into the plate 2. The multiple second power supply terminals 7 are built into the plate 2 in the central part of the plate 2 in a plan view and are electrically connected to one of the multiple jumper layers 5, corresponding to one of the multiple jumper layers 5. The multiple jumper layers 5 are electrically connected to the second heater layer 4, thereby making the multiple second power supply terminals 7 and the second heater layer 4 conductive. For example, a metal second power supply member 70, which is rod-shaped, is electrically connected to the multiple second power supply terminals 7. Current is passed through the second heater layer 4 from an external heater power supply via the second power supply member 70, the second power supply terminals 7, and the jumper layers 5.

[0040] In the ceramic heater 1, at least one of an RF electrode (high-frequency electrode) and an ESC electrode (electrostatic chuck electrode) 8, or an electrode 8 that functions as either an RF electrode or an ESC electrode, may be further provided inside the plate 2. The RF electrode generates plasma between itself and an upper electrode installed on the ceiling of the vacuum chamber when a high-frequency voltage is applied. The ESC electrode chucking the wafer W supported by the plate 2 by electrostatic attraction when a voltage is applied.

[0041] Electrode 8 is preferably disposed closer to the first main surface 22 than the first heater layer 3 in the thickness direction of the plate 2. The plate 2 incorporates a third power supply terminal 9, which is a terminal for supplying power to the electrode 8, at the central portion of the plate 2 in a plan view. A third power supply member 90 made of metal and having, for example, a rod shape is electrically connected to the third power supply terminal 9. The electrode 8 is energized, for example, from an external high-frequency power supply or the like via the third power supply member 90 and the third power supply terminal 9.

[0042] Each of the power supply members 60, 70, and 90 is electrically connected to the corresponding power supply terminal 6, 7, or 9 by being inserted into the plate 2 from the second main surface 23 into the interior of the plate 2 at the central portion of the plate 2 in a plan view.

[0043] <Explanation of the plate> Referring to FIG. 1, the plate 2 is a ceramic plate. The plate 2 contains, as a main component, aluminum nitride (AlN), aluminum oxide (Al O ３ ), silicon carbide (SiC), silicon nitride (Si ３ N ４ ) and the like. The plate 2 preferably contains aluminum nitride, which has a high thermal conductivity, as a main component. Here, the "main component" means the component with the highest content rate among the contained components, and the content rate of the main component is, for example, 50% by mass or more, preferably 70% by mass or more, and more preferably 90% by mass or more. The plate 2 may contain other components such as components derived from a sintering aid as long as it contains the above-described materials as a main component. Examples of the sintering aid include rare earth metal oxides. The plate 2 is formed, for example, of a ceramic sintered body obtained by sintering ceramic powder, but may also be formed by other methods such as a laminate formed by laminating and firing a plurality of green sheets obtained by kneading ceramic powder and a binder into a sheet.

[0044] The plate 2 has a first main surface 22 and a second main surface 23 which are spaced apart in the thickness direction. The first main surface 22 and the second main surface 23 are parallel or substantially parallel. Here, "substantially parallel" includes cases where one is slightly inclined within the tolerance with respect to the other, and cases where at least one is slightly distorted and not flat. In the present disclosure, in the thickness direction of the plate 2, the first main surface 22 side is defined as the upper side, and the second main surface 23 side is defined as the lower side.

[0045] In the present embodiment, the planar shape of the plate 2 is circular, but it is not limited to a circle. Note that the circle does not necessarily have to be a perfect circle, and for example, an imperfect circle lacking a part like an orientation flat may be used. The diameter of the plate 2 may be appropriately determined according to the diameter of the wafer W supported by the plate 2. The diameter of the plate 2 is, for example, 200 mm or more and 400 mm or less. The thickness of the plate 2 is, for example, 5 mm or more and 30 mm or less.

[0046] The first main surface 22 of the plate 2 includes a wafer support region 24 for supporting the wafer W. The entire area of the first main surface 22 may be the wafer support region 24, but as in the present embodiment, an outer peripheral wall 25 that bulges over the entire circumference in the circumferential direction of the plate 2 may be provided in a region having a predetermined width from the outer peripheral edge inward on the first main surface 22. If an outer peripheral wall 25 that surrounds the wafer is provided around the wafer support region 24, it becomes easy to position the wafer W.

[0047] In the wafer support region 24 of the first main surface 22, for example, an annular projection called a so-called seal band is provided, and the wafer W may be placed on the annular projection. Thereby, a space surrounded by the annular projection can be formed between the wafer W and the plate 2. Then, by supplying a gas with good thermal conductivity such as helium gas into this space, heat conduction between the wafer W and the plate 2 can be efficiently performed.

[0048] The wafer support region 24 of the first main surface 22 may have multiple small protrusions, for example, cylindrical or frustoconical. These multiple small protrusions can be provided, for example, in the region of the wafer support region 24 surrounded by an annular protrusion, at equal intervals from each other. The height of each small protrusion is the same as or approximately the same as the height of the annular protrusion. By placing the wafer W not only on the annular protrusion but also on the multiple small protrusions, the entire wafer W can be supported evenly.

[0049] The plate 2 may have various holes extending in the thickness direction of the plate 2. For example, holes may be formed in the plate 2 for inserting a lift pin used to lift the wafer W from the plate 2 after a film deposition process on the wafer W is completed. Also, holes may be formed in the plate 2 for supplying gas to the space surrounded by annular protrusions between the wafer W and the plate 2. Furthermore, holes may be formed in the plate 2 for passing a thermocouple for measuring the temperature of the plate 2.

[0050] Referring to Figure 3, in this embodiment, the inner zone 20 is a circular region, and the outer zone 21 is an annular region arranged concentrically with the inner zone 20, in accordance with the plan view shape of the plate 2. The diameter of the inner zone 20 is, for example, 0.25 times or more and 0.75 times or less the diameter of the plate 2. The outer diameter of the outer zone 21 is larger than the diameter of the inner zone 20 and, for example, 1 time or less the diameter of the plate 2.

[0051] (Description of the first heater layer) Referring to Figures 1 to 3, the first heater layer 3 extends planarly within the plate 2 along a virtual plane parallel or approximately parallel to the first main surface 22. The first heater layer 3 has, for example, a circular or approximately circular shape in plan view and is arranged concentrically with the plate 2. The first heater layer 3 is located in the inner zone 20 in plan view, and the outer edge of the first heater layer 3 coincides with or approximately coincides with the outer edge of the inner zone 20.

[0052] The first heater layer 3 is formed by a resistance heating element (hereinafter referred to as the "first resistance heating element") whose main component is a conductive material such as a high-melting-point metal, an alloy of a high-melting-point metal, or a carbide of a high-melting-point metal. Examples of high-melting-point metals include molybdenum (Mo), tungsten (W), and niobium (Nb).

[0053] The first resistive heating element consists of, for example, a thin plate having a planar shape corresponding to the planar shape of the inner zone 20, a thin plate with numerous through holes such as a punching plate, a mesh, or a film formed by printing conductive paste. Alternatively, the first resistive heating element consists of conductive paste, coils, and meandering wires wired in a predetermined pattern in a single continuous line over the entire or substantially entire area of ​​the inner zone 20. Preferably, the first resistive heating element is formed by printing conductive paste in a predetermined pattern. In this case, the first power supply terminals 6 are electrically connected to both ends of the wiring pattern of the first resistive heating element.

[0054] <Description of the Second Heater Layer> Referring to Figures 1 to 5, the second heater layer 4 extends planarly within the plate 2 along a virtual plane that is parallel or approximately parallel to the first main surface 22. The second heater layer 4 is positioned below the first heater layer 3 in the thickness direction of the plate 2, but it may also be positioned above the first heater layer 3. It is preferable that the second heater layer 4 is positioned below the first heater layer 3.

[0055] The second heater layer 4 has, for example, an annular or roughly annular shape in plan view, and is arranged concentrically with the plate 2 outside the outer edge of the first heater layer 3 in plan view. The second heater layer 4 is located in the outer zone 21 in plan view, and the outer edge of the second heater layer 4 coincides with or roughly coincides with the outer edge of the outer zone 21. The inner edge of the outer zone 21 coincides with the outer edge of the inner zone 20.

[0056] The second heater layer 4 is formed by a resistance heating element 42 (hereinafter referred to as "second resistance heating element 42") whose main component is a conductive material such as a high-melting-point metal, an alloy of a high-melting-point metal, or a carbide of a high-melting-point metal. Examples of high-melting-point metals include molybdenum (Mo), tungsten (W), and niobium (Nb).

[0057] The second resistive heating element 42 consists of, for example, a thin plate having a planar shape corresponding to the planar shape of the outer zone 21, a thin plate with numerous through holes such as a perforated plate, a mesh, or a film formed by printing conductive paste. Alternatively, the second resistive heating element 42 consists of conductive paste, coils, and meandering wires wired in a predetermined pattern in a single continuous line over the entire or substantially entire area of ​​the outer zone 21. Preferably, the second resistive heating element 42 is formed by wiring conductive paste in a predetermined pattern by printing, as in this embodiment.

[0058] Multiple connection portions 40 are integrally formed on the inner periphery of the second heater layer 4. The number of connection portions 40 corresponds to the number of jumper layers 5, and in this embodiment, two connection portions 40, the first connection portion 40A and the second connection portion 40B, are integrally formed on the second heater layer 4. The first connection portion 40A and the second connection portion 40B are formed, for example, at a pair of opposing positions on the inner periphery of the second heater layer 4. Note that the positions where the first connection portion 40A and the second connection portion 40B are arranged are not limited to opposing positions, but may be any suitable and preferable position.

[0059] The multiple connection portions 40 are resistance heating elements formed from the same conductive material as the second heater layer 4, and consist of a film formed by printing a conductive paste, for example. The multiple connection portions 40 protrude inward from the inner peripheral edge of the second heater layer 4, that is, toward the center of the plate 2. The multiple connection portions 40 electrically connect the second heater layer 4 and the jumper layer 5.

[0060] If the second resistive heating element 42 forming the second heater layer 4 is a printing paste wired in a predetermined pattern, the wiring pattern of the second resistive heating element 42 may be a parallel circuit or a series circuit.

[0061] Figure 7 conceptually shows an example where the wiring pattern of the second resistive heating element 42 is a parallel circuit when there are two jumper layers 5. In Figure 7, the arrows indicate the direction of current. In the example shown in Figure 7, the wiring pattern of the second resistive heating element 42 in the second heater layer 4 extends in two directions from the first connection point 40A with the first jumper layer 5A of one of the two jumper layers 5, and in each of the two directions, it reaches the second connection point 40B with the other second jumper layer 5B in a single continuous line. When the wiring pattern of the second resistive heating element 42 forming the second heater layer 4 is a parallel circuit, the first connection point 40A and the second connection point 40B are formed, for example, at a pair of opposing positions on the inner periphery of the second heater layer 4.

[0062] Figure 8 conceptually illustrates an example where the wiring pattern of the second resistive heating element 42 is a series circuit when there are two jumper layers 5. In Figure 8, arrows indicate the direction of current. In the example shown in Figure 8, the wiring pattern of the second resistive heating element 42 in the second heater layer 4 extends in one direction from the first connection point 40A with the first jumper layer 5A to the second connection point 40B with the second jumper layer 5B in a single continuous line. When the wiring pattern of the second resistive heating element 42 forming the second heater layer 4 is a series circuit, the first connection point 40A and the second connection point 40B are formed, for example, at adjacent positions on the inner periphery of the second heater layer 4.

[0063] In this embodiment, the wiring pattern of the second resistive heating element 42 in the second heater layer 4 is a parallel circuit. From the viewpoint of uniform heating of the plate 2, both a series circuit and a parallel circuit can achieve the same level of uniform heating, but from the viewpoint of preventing an increase in resistance, a parallel circuit is preferable.

[0064] <Description of Jumper Layers> Referring to Figures 1 to 4 and Figure 6, the multiple jumper layers 5 spread out planarly within the plate 2 along a virtual plane that is parallel or approximately parallel to the first main surface 22. The multiple jumper layers 5 are positioned below the first heater layer 3 in the thickness direction of the plate 2 and at the same height as the second heater layer 4. Note that the same height includes positions where the height is exactly the same and positions where the height is approximately the same. The multiple jumper layers 5 are positioned in the inner zone 20 in a plan view, and the outer edges of the multiple jumper layers 5 may coincide with the outer edge of the inner zone 20, or they may be located inside or outside the outer edge of the inner zone 20.

[0065] Multiple jumper layers 5 are formed from resistance heating elements (hereinafter referred to as "third resistance heating elements") whose main component is a conductive material such as a high-melting-point metal, an alloy of a high-melting-point metal, or a carbide of a high-melting-point metal. Examples of high-melting-point metals include molybdenum (Mo), tungsten (W), and niobium (Nb).

[0066] The third resistive heating element consists of, for example, a thin plate having a planar shape corresponding to the planar shape of the inner zone 20 when all components are combined, a thin plate with numerous through holes such as a punching plate, a mesh, or a film formed by printing conductive paste. Preferably, the third resistive heating element is formed by printing conductive paste into a predetermined shape.

[0067] Multiple jumper layers 5 are arranged at intervals in the circumferential direction of the plate 2 in a plan view, and are positioned in a non-contact state, spaced apart from each other. The number of jumper layers 5 corresponds to the number of second power supply terminals 7, and in this embodiment, two jumper layers 5, the first jumper layer 5A and the second jumper layer 5B, are positioned in a non-contact state, spaced apart from each other.

[0068] When there are two jumper layers 5, the plan view shape of the two jumper layers 5, the first jumper layer 5A and the second jumper layer 5B, is semicircular or approximately semicircular. For example, the first jumper layer 5A has a through hole 18 through which the first power supply member 60 and the third power supply member 90 can pass. The number of jumper layers 5 is not limited to two; there may be three or more, or even four or more, to match the number of second power supply terminals 7. When there are four jumper layers 5, the plan view shape of the four jumper layers 5 is quarter-circular or approximately quarter-circular.

[0069] In each of the multiple jumper layers 5, one of the multiple connection parts 40 of the second heater layer 4 is electrically connected to the vicinity of the first radial portion 51, which corresponds to approximately the radius of the jumper layer 5, at the outer edge, and one of the multiple second power supply terminals 7 is electrically connected to the vicinity of the center. Specifically, in this embodiment, the first jumper layer 5A has the first connection part 40A of the second heater layer 4 electrically connected to the vicinity of the first radial portion 51 at the outer edge, and one of the second power supply terminals 7A is electrically connected to the vicinity of the center. In the second jumper layer 5B, the second connection part 40B of the second heater layer 4 is electrically connected to the vicinity of the first radial portion 51 at the outer edge, and the other second power supply terminal 7B is electrically connected to the vicinity of the center.

[0070] The second power supply terminal 7 for supplying power to the second heater layer 4 is located in the center of the plate 2 in a plan view, while the second heater layer 4 is located in the outer zone 21 of the plate 2, away from the second power supply terminal 7. Therefore, the jumper layer 5 makes electrical contact between the second heater layer 4 and the second power supply terminal 7, thereby electrically connecting the second heater layer 4 and the second power supply terminal 7.

[0071] Multiple jumper layers 5 have at least one slit 15 formed in them. The slit 15 is an elongated hole that extends along the circumferential direction of the plate 2 in a plan view and penetrates the jumper layer 5 in the thickness direction. In this embodiment, there is one slit 15 formed in the jumper layer 5.

[0072] The plan view shape of the slit 15 is, for example, an arc shape. The slit 15 extends in an arc shape from a starting end 16 located outside the second power supply terminal 7 in the first radial portion 51, which is roughly the radius of the jumper layer 5, to a ending end 17. The ending end 17 of the slit 15 is located away from the second radial portion 52, which is the portion of the jumper layer 5 that is roughly the radius and opposite to the first radial portion 51 where the starting end 16 is located. As a result, the jumper layer 5 includes a first region 55 inside the slit 15, extending in the positive circumferential direction of the plate 2 from the first end 53 to which the second power supply terminal 7 is connected. The jumper layer 5 also includes a second region 56 outside the slit 15, extending in the negative circumferential direction of the plate 2 to the second end 54 to which the connection portion 40 is connected. Furthermore, the jumper layer 5 includes a first folding region 58 between the second radial portion 52 and the end 17 of the slit 15, which folds back from the first region 55 to the second region 56.

[0073] In this disclosure, the positive direction in the circumferential direction of plate 2 refers to the direction in which the plate 2 rotates around its center, with the center of plate 2 positioned on either the left or right side, while the negative direction refers to the direction opposite to the positive direction. In this embodiment, the positive direction corresponds to the counterclockwise direction, and the negative direction corresponds to the clockwise direction.

[0074] Multiple jumper layers 5 are formed by creating a single slit 15, so that in a plan view, a first region 55 extending in the positive circumferential direction of the plate 2 and a second region 56 extending in the negative circumferential direction of the plate 2 are connected via a first folding region 58, from the center of the plate 2 toward the outer edge, forming a zigzag shape that is alternately folded in the positive and negative directions. As a result, for example, in the first jumper layer 5A, the current transmitted from one of the second power supply terminals 7A to the first jumper layer 5A passes from the first end 53 through the first region 55, folds back at the first folding region 58, passes through the second region 56 to the second end 54, and is transmitted to the second heater layer 4 via the first connection part 40A. Then, in the second jumper layer 5B, the current transmitted from the second heater layer 4 to the second jumper layer 5B via the second connection part 40B passes from the second end 54 through the second region 56, folds back in the first folding region 58, passes through the first region 55 to the first end 53, and is transmitted to the other second power supply terminal 7B.

[0075] The number of slits 15 formed in the jumper layer 5 is not necessarily limited to one, and may be two or more. Figure 9 shows an example in which the slits 15 formed in the two jumper layers 5, the first jumper layer 5A and the second jumper layer 5B, are two slits, the first slit 15A and the second slit 15B, which have an arc shape in plan view.

[0076] In the example shown in Figure 9, the first slit 15A extends in an arc from a starting end 16A located outside the second power supply terminal 7 in the first radial portion 51 to a ending end 17A. The ending end 17A of the first slit 15A is located away from the second radial portion 52 of the jumper layer 5. The second slit 15B extends in an arc from a starting end 16B located outside the ending end 17A of the first slit 15A in the second radial portion 52 of the jumper layer 5 to a ending end 17B. The ending end 17B of the second slit 15B is located away from the first radial portion 51 of the jumper layer 5. As a result, the jumper layer 5 includes a first region 55 inside the first slit 15A, extending in the positive circumferential direction of the plate 2 from the first end 53 to which the second power supply terminal 7 is connected. Furthermore, the jumper layer 5 includes a second region 56 extending in the positive circumferential direction of the plate 2 to the second end 54 to which the connecting portion 40 is connected, outside the second slit 15B. The jumper layer 5 also includes a third region 57 extending in the negative circumferential direction of the plate 2 between the first region 55 and the second region 56. The jumper layer 5 also includes a first folded-back region 58 between the second radial portion 52 and the end 17A of the first slit 15A, which folds back from the first region 55 to the second region 56. The jumper layer 5 also includes a second folded-back region 59 between the first radial portion 51 and the end 17B of the second slit 15B, which folds back from the second region 56 to the third region 57.

[0077] Multiple jumper layers 5 are formed with two slits 15A and 15B, so that in a plan view, extending from the center of the plate 2 towards the outer edge, the first region 55 extends in the positive direction of the circumferential direction of the plate 2, the third region 57 extends in the negative direction of the circumferential direction of the plate 2, and the second region 56 extends in the positive direction of the circumferential direction of the plate 2 are connected via a first folded region 58 and a second folded region 59, forming a zigzag shape that alternately bends in the positive, negative, and positive directions. As a result, for example, in the first jumper layer 5A, the current transmitted from one of the second power supply terminals 7A to the first jumper layer 5A passes from the first end 53 through the first region 55, folds back at the first folded region 58, passes through the third region 57, folds back at the second folded region 59, passes through the second region 56 to the second end 54, and is transmitted to the second heater layer 4 via the first connection part 40A. Then, in the second jumper layer 5B, the current transmitted from the second heater layer 4 to the second jumper layer 5B via the second connection part 40B passes from the second end 54 through the second region 56, folds back in the second folding region 59, passes through the third region 57, folds back in the first folding region 58, passes through the first region 55 to the first end 53, and is transmitted to the other second power supply terminal 7B.

[0078] As described above, the multiple jumper layers 5 are configured such that, in a plan view, the multiple regions are connected in a zigzag pattern, from the innermost first region 55 which includes the first end 53 to which the second power supply terminal 7 is connected, to the outermost second region 56 which includes the second end 54 to which the connection portion 40 is connected. Therefore, in the multiple jumper layers 5, when current is supplied to the second heater layer 4 and conduction is made between the second heater layer 4 and the second power supply terminal 7, the current spreads over a wide area of ​​the jumper layer 5. Since the jumper layer 5 is formed of a resistive heating element, the jumper layer 5 also generates heat when current is supplied to the second heater layer 4, but in this embodiment, the jumper layer 5 generates heat uniformly over its entire or nearly entire area. Therefore, it is possible to suppress the occurrence of localized hot spots and cool spots on the plate 2 due to the heat generated by the jumper layer 5 itself, thereby improving the uniformity of the heat distribution of the plate 2.

[0079] Referring to Figure 6, the central angle θ of the slit 15 is not particularly limited, but when n is the number of jumper layers 5 arranged at the same height in the thickness direction inside the plate 2, it is preferably 1 / 2 × 360° / n or more and 5 / 6 × 360° / n or less, and more preferably 2 / 3 × 360° / n or more and 5 / 6 × 360° / n or less. The central angle θ of the slit 15 refers to the angle formed by the first line segment connecting the center of the plate 2 and the starting end 16, which is one end of the slit 15, in a plan view, and the second line segment connecting the center of the plate 2 and the ending end 17, which is the other end of the slit 15 (the end opposite to the starting end 16).

[0080] When there are two jumper layers 5, as in the example shown in Figure 6, the central angle θ of the slit 15 is preferably 90° or more and 150° or less, more preferably 100° or more and 150° or less, more preferably 100° or more and 140° or less, and more preferably 120° or more and 140° or less. For example, when there are four jumper layers 5, the central angle θ of the slit 15 is preferably 45° or more and 75° or less, more preferably 50° or more and 75° or less, more preferably 50° or more and 70° or less, and more preferably 60° or more and 70° or less.

[0081] By having a central angle θ of slit 15 of 1 / 2 × 360° / n or greater, the current can be distributed over a wider area of ​​the jumper layer 5. This improves the uniformity of the heat distribution of the plate 2. On the other hand, by having a central angle θ of slit 15 of 5 / 6 × 360° / n or less, the width of the folded regions 58-59 is narrowed, which suppresses localized heat generation in the plate 2.

[0082] The width of the slit 15 is not particularly limited, but is preferably 1.0 mm or more and 3.0 mm or less, and more preferably 1.5 mm or more and 2.5 mm or less. The width of the slit 15 refers to the length of the portion where the radius extending from the center of the plate 2 to the outer edge crosses the slit 15 in a plan view. By having a width of 1.0 mm or more for the slit 15, insulation can be ensured between the two regions of the jumper layer 5 that sandwich the slit 15. On the other hand, by having a width of 3.0 mm or less for the slit 15, the width of each region 55 to 57 in the jumper layer 5 can be increased, and as a result the area of ​​each region 55 to 57 increases, the resistance of each region 55 to 57 can be reduced.

[0083] The width of each region in the jumper layer 5, that is, the width of the first region 55 and the width of the second region 56 in the example shown in Figure 6, and the width of the first region 55, the width of the second region 56 and the width of the third region 57 in the example shown in Figure 9, is greater than the width of the second resistance heating element 42 that forms the second heater layer 4. The widths of the multiple regions 55 to 57 and the width of the second resistance heating element 42 refer to the length of the portion where the radius extending from the center to the outer edge of the plate 2 in a plan view crosses each of the regions 55 to 57 and the second resistance heating element 42.

[0084] If the width of each region 55-57 in the jumper layer 5 is large, the area increases, and thus the resistance of each region 55-57 in the jumper layer 5 is reduced. This reduces the amount of heat generated in the jumper layer 5 when current is supplied to the second heater layer 4. Therefore, the uniformity of heat distribution of the plate 2 can be improved.

[0085] On the other hand, by not making the width of each region 55-57 in the jumper layer 5 too large compared to the width of the second resistive heating element 42 that forms the second heater layer 4, the proportion of heat generated in the jumper layer 5 is suppressed, thereby improving the uniformity of the heat distribution of the plate 2.

[0086] Therefore, the width of each region 55 to 57 in the jumper layer 5 is preferably 2 to 75 times the width of the second resistive heating element 42 forming the second heater layer 4, and more preferably 4 to 15 times.

[0087] Thus, in order to make the width of each region 55 to 57 in the jumper layer 5 an appropriate size, the number of slits 15 formed in the multiple jumper layers 5 is preferably one or two, and more preferably one.

[0088] The number of slits 15 formed in the multiple jumper layers 5 does not necessarily have to be the same; they may be different.

[0089] Referring to Figures 2 and 10A, the thickness T2 of the jumper layer 5 is not particularly limited, but it is preferable that it be greater than the thickness T1 of the second heater layer 4. By making the thickness T2 of the jumper layer 5 greater than the thickness T1 of the second heater layer 4, the resistance of the jumper layer 5 is significantly reduced. This effectively reduces the amount of heat generated in the jumper layer 5 when current is supplied to the second heater layer 4. Therefore, the uniformity of the heat distribution of the plate 2 can be further improved.

[0090] On the other hand, if the thickness T2 of the jumper layer 5 is too large compared to the thickness T1 of the second heater layer 4, a large step will be created at the connection point 40 between the jumper layer 5 and the second heater layer 4. This can cause stress to concentrate at this step during the manufacturing or use of the ceramic heater 1, potentially leading to breakage.

[0091] Therefore, the thickness T2 of the jumper layer 5 is preferably 1.2 times or more and 3.0 times or less the thickness T1 of the second heater layer 4, more preferably 1.3 times or more and 2.8 times or less, more preferably 1.4 times or more and 2.5 times or less, and more preferably 1.5 times or more and 2.0 times or less.

[0092] Referring to Figure 3, the area of ​​the multiple jumper layers 5 in a plan view is not particularly limited, but it is preferably 75% to 98% of the area of ​​the inner zone 20, preferably 80% to 95%, and more preferably 90% to 95%. When the area ratio of the multiple jumper layers 5 is 75% or more, and the area of ​​the jumper layers 5 is large, the resistance of the jumper layers 5 is reduced effectively. As a result, the amount of heat generated in the jumper layers 5 when the second heater layer 4 is energized can be reduced effectively. Therefore, the uniformity of the heat distribution of the plate 2 can be improved.

[0093] Table 1 below shows the results of measuring the uniformity of the plate 2 for test examples 1 to 7, in which the ratio of the area of ​​the multiple jumper layers 5 to the area of ​​the inner zone 20 was varied. The uniformity of the plate 2 is evaluated by the difference between the highest and lowest temperatures when the temperature of the first main surface 22 of the plate 2 is measured. The temperature measurement area on the first main surface 22 is the entire area of ​​the inner zone 20 and a portion of the outer zone 21 near the boundary with the inner zone 20. According to Table 1, it can be seen that the uniformity of the plate 2 can be improved by having a ratio of the area of ​​the multiple jumper layers 5 of 75% or more.

[0094]

[0095] Referring to Figure 10A, the connection portion 40 of the second heater layer 4 may be connected to the jumper layer 5 in such a manner that the outer edge of the jumper layer 5 rests on the leading edge of the connection portion 40. In other words, the thickness T3 of the connecting portion 41 where the connection portion 40 of the second heater layer 4 and the jumper layer 5 are connected is greater than the thickness T2 of the jumper layer 5 and the thickness T1 of the second heater layer 4. Note that the connection portion 40 of the second heater layer 4 may be connected to the jumper layer 5 in such a manner that the leading edge of the connection portion 40 rests on the outer edge of the jumper layer 5.

[0096] The connecting portion 41 where the connection portion 40 of the second heater layer 4 and the jumper layer 5 are connected tends to generate heat due to the concentration of current when the second heater layer 4 is energized. However, as shown in the example in Figure 10A, increasing the thickness T3 of the connecting portion 41 reduces the resistance of the connecting portion 41. This reduces the amount of heat generated at the connecting portion 41 when the second heater layer 4 is energized, thereby suppressing the occurrence of localized hot spots. As a result, the uniformity of the heat distribution of the plate 2 can be improved.

[0097] The connection portion 40 of the second heater layer 4 may be connected to the jumper layer 5 in such a manner that the leading edge of the connection portion 40 abuts against the outer edge of the jumper layer 5, as shown in Figure 10B.

[0098] (Description of the shaft) Referring to Figure 1, the shaft 10 is formed in a cylindrical shape having a pair of openings, a first opening 11 and a second opening 12, located at both ends in the axial direction. The shaft 10 supports the plate 2 on the side of the second main surface 23 (the surface opposite to the first main surface 22 on which the wafer is supported). The shaft 10 is positioned such that, for example, the cross-sectional shape of the shaft when cut by a plane perpendicular to the axial direction is circular and it is concentric with the plate 2. The diameter of the shaft 10 is smaller than the diameter of the plate 2.

[0099] The shaft 10 may be formed from a sintered body made of the same ceramic material as the plate 2, or from a sintered body made of a different ceramic material.

[0100] In the shaft 10, the tip portion 13, which surrounds the first opening 11, and the base portion 14, which surrounds the second opening 12, can be formed by, for example, a flange. The tip portion 13 of the shaft 10 is joined to the second main surface 23 of the plate 2, for example, by diffusion bonding.

[0101] The internal space S of the shaft 10 houses various power supply members 60, 70, and 90, as well as thermocouples for measuring the temperature of the plate 2. This isolates these metal components, such as the power supply members 60, 70, and 90 and the thermocouples, from the external space, which is the vacuum chamber of the semiconductor manufacturing apparatus, preventing them from being exposed to plasma or other external elements.

[0102] (Explanation of the operation and effect of the ceramic heater) The ceramic heater 1 according to the above embodiment is characterized in that at least one slit 15 is formed in a plurality of jumper layers 5, and the plurality of jumper layers 5 are divided into a plurality of regions 55 to 57, which in plan view include at least an innermost first region 55 including a first end 53 to which a second power supply terminal 7 is connected, and an outermost second region 56 including a second end 54 to which a connection portion 40 is connected. Furthermore, the plurality of regions 55 to 57 are characterized in that the first region 55 extends in the positive direction in the circumferential direction of the plate 2, and the regions other than the first region 55 extend in the opposite direction in the circumferential direction of the plate 2 to the region one innermost, and are connected to each other in a zigzag manner via folded regions 58 to 59. In addition, the width of each region 55 to 57 in the jumper layer 5 is greater than the width of the second resistance heating element 42 that forms the second heater layer 4.

[0103] According to the ceramic heater 1 of this embodiment, due to the features described above, when current is supplied to the second heater layer 4, the current spreads over a wide area of ​​the jumper layer 5 when the second heater layer 4 and the second power supply terminal 7 are connected. Therefore, when current is supplied to the second heater layer 4, the jumper layer 5 heats up uniformly over its entire or nearly entire area. This suppresses the occurrence of localized hot spots and cool spots on the plate 2 due to the heat generated by the jumper layer 5 itself. Furthermore, because the width of each region 55-57 in the jumper layer 5 is large and the area of ​​each region 55-57 is large, the resistance of each region 55-57 in the jumper layer 5 is reduced. This reduces the amount of heat generated in the jumper layer 5 when current is supplied to the second heater layer 4. Thus, the uniformity of the heat distribution of the plate 2 can be improved.

[0104] In addition, the ceramic heater 1 according to this embodiment is characterized in that the width of each region 55 to 57 in the jumper layer 5 is 2 to 75 times the width of the second resistance heating element 42 that forms the second heater layer 4. According to the ceramic heater 1 according to this embodiment, this feature allows for a good reduction in the resistance of each region of the jumper layer, thereby effectively reducing the amount of heat generated in the jumper layer when current is supplied to the second heater layer. As a result, the uniformity of heating of the plate can be improved.

[0105] In addition, the ceramic heater 1 according to this embodiment is characterized in that the width of the slit is 1.0 mm or more. According to the ceramic heater 1 according to this embodiment, this feature makes it possible to ensure insulation between the two regions sandwiching the slit 15 in the jumper layer 5.

[0106] In addition, the ceramic heater 1 according to this embodiment is characterized in that a slit 15 is formed in each of the multiple jumper layers 5, dividing the jumper layer 5 into two regions, a first region 55 and a second region 56, in a plan view. According to the ceramic heater 1 according to this embodiment, this feature allows the width of each region 55-56 in the jumper layer 5 to be increased, thereby increasing the area of ​​each region 55-56 in the jumper layer 5 and effectively reducing the resistance of each region 55-56. Therefore, the amount of heat generated in the jumper layer 5 when current is supplied to the second heater layer 4 can be effectively reduced, and the uniformity of the heat distribution of the plate 2 can be further improved.

[0107] In addition, the ceramic heater 1 according to this embodiment is characterized in that the multiple connection portions 40 of the second heater layer 4 protrude inward toward the corresponding jumper layer 5 among the multiple jumper layers 5 and connect with the jumper layer 5. According to the ceramic heater 1 according to this embodiment, this feature allows the second heater layer 4 and the jumper layer 5 to be connected with a simple structure.

[0108] In addition, the ceramic heater 1 according to this embodiment is characterized in that the thickness of the connecting portion 41, which connects the connection portion 40 and the jumper layer 5, is greater than the thickness of the jumper layer 5 and the second heater layer 4. According to the ceramic heater 1 according to this embodiment, this feature reduces the resistance of the connecting portion 41 and reduces the amount of heat generated at the connecting portion 41 when power is supplied to the second heater layer 4. Therefore, the occurrence of localized hot spots on the plate 2 can be suppressed, and the uniformity of the heat distribution of the plate 2 can be improved.

[0109] In addition, the ceramic heater 1 according to this embodiment is characterized in that the thickness of the jumper layer 5 is greater than the thickness of the second heater layer 4. According to the ceramic heater 1 according to this embodiment, this feature effectively reduces the resistance of the jumper layer 5 and effectively reduces the amount of heat generated in the jumper layer 5 when current is supplied to the second heater layer 4. Therefore, the uniformity of the heat distribution of the plate 2 can be improved.

[0110] In addition, the ceramic heater 1 according to this embodiment is characterized in that the central angle of the slit 15 is 1 / 2 × 360° / n (where n is the number of jumper layers) or more. According to the ceramic heater 1 according to this embodiment, this feature allows the current to be distributed over a wider area of ​​the jumper layer 5 when the second heater layer 4 is energized. This improves the uniform heating of the plate 2.

[0111] In addition, the ceramic heater 1 according to this embodiment is characterized in that, in a plan view, the ratio of the area of ​​the multiple jumper layers 5 to the area of ​​the inner zone 20 is 75% or more. According to the ceramic heater 1 according to this embodiment, this feature effectively reduces the resistance of the jumper layers 5 and effectively reduces the amount of heat generated in the jumper layers 5 when current is supplied to the second heater layer 4. Therefore, the uniformity of the heat distribution of the plate 2 can be improved.

[0112] <Explanation of Modifications> The ceramic heater 1 according to one embodiment of the present disclosure has been described above, but the embodiment can be modified in various ways without departing from the spirit of the present disclosure. For example, the modifications described below are possible. The modifications described below can be combined as appropriate.

[0113] In the ceramic heater 1 according to the above embodiment, the multiple jumper layers 5 may be housed in the plate 2 in a state of separation from one another, by not being arranged at the same height in the thickness direction of the plate 2, but at different heights.

[0114] Specifically, as shown in Figures 11 and 12, a plurality of jumper layers 5, for example, two jumper layers 5, a first jumper layer 5A and a second jumper layer 5B, may be arranged inside the plate 2 at different heights in the thickness direction of the plate 2, separated from each other. In this modified example, in the thickness direction of the plate 2, the first jumper layer 5A is positioned at the same height as the second heater layer 4, and the second jumper layer 5B is positioned below both the first jumper layer 5A and the second heater layer 4.

[0115] Referring to Figures 12(A) and (B), the first jumper layer 5A and the second jumper layer 5B are, for example, circular or approximately circular in shape in plan view and are arranged concentrically with the plate 2. The first jumper layer 5A and the second jumper layer 5B have a single elongated notch 50 that extends from the outer edge to the center in plan view. The first connection portion 40A of the second heater layer 4 is electrically connected to the first jumper layer 5A near the notch 50 at its outer edge. The second connection portion 40B of the second heater layer 4 is electrically connected to the second jumper layer 5B near the notch 50 at its outer edge.

[0116] Referring to Figure 11, the second connection portion 40B has an L-shaped cross-sectional form, including a vertical portion 400 extending from the second heater layer 4 in the thickness direction of the plate 2, and a horizontal portion 401 extending horizontally from the lower end of the vertical portion 400 and connecting to the second jumper layer 5B. Similar to the example shown in Figure 10A, it is preferable that the thickness of the connecting portion where the horizontal portion 401 of the second connection portion 40B and the second jumper layer 5B are connected is greater than the thickness of the jumper layer 5 and the thickness of the second heater layer 4. Note that the second connection portion 40B does not need to have an L-shaped cross-sectional form; the second connection portion 40B and the second jumper layer 5B may be electrically connected vertically using a conductive member extending in the thickness direction of the plate 2.

[0117] Referring to Figures 12(A) and (B), a slit 15 is formed in the first jumper layer 5A and the second jumper layer 5B, for example. The plan view shape of the slit 15 is, for example, an arc shape, and the slit 15 extends in an arc from a starting end 16 located outside the second power supply terminal 7 in the notch 50 of the first jumper layer 5A and the second jumper layer 5B to a ending end 17 located in front of the notch 50. The ending end 17 of the slit 15 is located away from the notch 50 of the first jumper layer 5A and the second jumper layer 5B. As a result, the first jumper layer 5A and the second jumper layer 5B include, inside the slit 15, a first region 55 extending in the positive circumferential direction of the plate 2 from the first end 53 to which the second power supply terminal 7 is connected, a second region 56 extending in the negative circumferential direction of the plate 2 to the second end 54 to which the connection portion 40 is connected, and a first folded-back region 58 that folds back from the first region 55 to the second region 56.

[0118] In this modified example, in the first jumper layer 5A, the current transmitted from one of the second power supply terminals 7A to the first jumper layer 5A passes from the first end 53 through the first region 55, folds back at the first folding region 58, passes through the second region 56 to the second end 54, and is transmitted to the second heater layer 4 via the first connection part 40A. In the second jumper layer 5B, the current transmitted from the second heater layer 4 to the second jumper layer 5B via the second connection part 40B passes from the second end 54 through the second region 56, folds back at the first folding region 58, passes through the first region 55 to the first end 53, and is transmitted to the other second power supply terminal 7B. As a result, the first jumper layer 5A and the second jumper layer 5B generate heat uniformly throughout or almost entirely when the second heater layer 4 is energized.

[0119] The central angle of the slit 15 is preferably 180° or more and 300° or less, more preferably 200° or more and 300° or less, more preferably 200° or more and 280° or less, and more preferably 240° or more and 280° or less.

[0120] The number of slits 15 formed in the first jumper layer 5A and the second jumper layer 5B is not necessarily limited to one, and may be two or more as in the above embodiment, but it is preferable to have one or two.

[0121] In the ceramic heater 1 according to the above embodiment, the shape of the slit 15 does not have to be a smoothly curved shape like an arc in plan view, but may be an angular curved shape.

[0122] The embodiments disclosed herein should be understood to be illustrative in all respects and not restrictive in any way. The scope of the invention is defined by the claims and not by the foregoing description, and all modifications within the meaning and scope of the claims are intended to be included.

[0123] 1: Ceramic heater, 2: Plate, 3: First heater layer, 4: Second heater layer, 5: Jumper layer, 5A: First jumper layer, 5B: Second jumper layer, 6: First power supply terminal, 7: Second power supply terminal, 7A: One second power supply terminal, 7B: The other second power supply terminal, 8: Electrode, 9: Third power supply terminal, 10: Shaft, 11: First opening, 12: Second opening, 13: Tip of shaft, 14: Base of shaft, 15: Slit, 15A: First slit, 15B: Second slit, 16: Start of slit, 16A: Start of first slit, 16B: Start of second slit, 17: End of slit, 17A: End of first slit, 17B: End of second slit, 18: Through hole, 19: Conductive member, 20: Inside Zone, 21: Outer zone, 22: First main surface, 23: Second main surface, 24: Wafer support area, 25: Outer peripheral wall, 40: Connection part, 40A: First connection part, 40B: Second connection part, 41: Connecting part, 42: Second resistance heating element, 50: Notch, 51: First radius part, 52: Second radius part, 53: First end, 54: Second end, 55: First region, 56: Second region, 57: Third region, 58: First folded region, 59: Second folded region, 60: First power supply member, 70: Second power supply member, 90: Third power supply member, 400: Vertical part of connection part, 401: Horizontal part of connection part, S: Internal space of shaft, T1: Thickness of second heater layer, T2: Thickness of jumper layer, T3: Thickness of connecting part, W: Wafer, θ: Center angle of slit

Claims

1. A plate having a first main surface for supporting a wafer and a second main surface positioned at a distance from the first main surface in the thickness direction; a first heater layer built into the plate and formed of a resistance heating element that generates heat when energized; a plurality of first power supply terminals built into the plate so as to be positioned in the center of the plate when viewed along the thickness direction and connected to the first heater layer; an annular second heater layer built into the plate so as to be positioned outside the first heater layer when viewed along the thickness direction and formed of a resistance heating element that generates heat when energized; a plurality of second power supply terminals built into the plate so as to be positioned in the center of the plate when viewed along the thickness direction and for supplying power to the second heater layer; a plurality of jumper layers built into the plate so as to be positioned on the second main surface side of the first heater layer in the thickness direction and on the inside of the second heater layer when viewed along the thickness direction, A ceramic heater wherein the plurality of jumper layers are connected to a corresponding second power supply terminal among a plurality of second power supply terminals, and are connected to the second heater layer via a corresponding connection portion among a plurality of connection portions provided on the second heater layer, and the plurality of jumper layers have at least one slit formed therein that divides the jumper layer into a plurality of regions, which when viewed along the thickness direction, the first region extends in the positive direction of the circumferential direction and the regions other than the first region extend in the opposite direction of the circumferential direction to the region one innermost, and the width of each of the plurality of regions is greater than the width of the resistance heating element forming the second heater layer.

2. The ceramic heater according to claim 1, wherein the width of each of the plurality of regions is 2 times or more and 75 times or less the width of the resistance heating element forming the second heater layer.

3. The ceramic heater according to claim 1, wherein the width of the slit is 1.0 mm or more.

4. The ceramic heater according to claim 1, wherein each of the plurality of jumper layers has a slit that divides the jumper layer into two regions when viewed along the thickness direction: a first region extending from the first end in the positive direction of the circumferential direction, and a second region extending to the second end in the negative direction of the circumferential direction, opposite to the positive direction.

5. The ceramic heater according to any one of claims 1 to 4, wherein the plurality of connection portions of the second heater layer protrude inward toward the corresponding jumper layer among the plurality of jumper layers and connect with the jumper layer.

6. The ceramic heater according to claim 5, wherein the thickness of the connecting portion connecting the connection portion and the jumper layer is greater than the thickness of the jumper layer and the second heater layer.

7. The ceramic heater according to any one of claims 1 to 4, wherein the thickness of the jumper layer is greater than the thickness of the second heater layer.

8. The ceramic heater according to any one of claims 1 to 4, wherein the plurality of jumper layers are arranged inside the plate at the same height in the thickness direction and are separated from each other in the circumferential direction when viewed in the thickness direction, and the angle between the first line segment connecting the center of the plate and one end of the slit and the second line segment connecting the center of the plate and the other end of the slit when viewed in the thickness direction is 1 / 2 × 360° / n (where n is the number of the plurality of jumper layers) or more.

9. The ceramic heater according to any one of claims 1 to 4, wherein the plate includes an inner zone which is a circular region within a first distance from the center of the plate and in which the first heater layer and the plurality of jumper layers are arranged, and an outer zone which is an annular region within a second distance from the center of the plate and outside the inner zone and in which the second heater layer is arranged, and the ratio of the area of ​​the plurality of jumper layers to the area of ​​the inner zone is 75% or more.

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