Ceramic heater

Abstract

To provide a ceramic heater.SOLUTION: A ceramic heater includes: a plate having a heating element and a first passage; and a shaft having a hollow portion. The heating element has: a plurality of concentric arcuate parts; and a plurality of connection parts which connect the arcuate parts. A separation region, which is formed by the plurality of connection parts facing in a manner being spaced apart from each other at a predetermined distance, extends in the radial direction of the plate. The first passage is formed adjacent to the separation region.SELECTED DRAWING: Figure 18

Description

Technical Field

[0001] The present invention relates to a ceramic heater, and more specifically, to a ceramic heater in which the structure of a passage into which a temperature sensor is inserted is improved.

Background Art

[0002] Generally, in order to manufacture a flat panel display panel or a semiconductor element, a series of layers including a dielectric layer and a metal layer are sequentially laminated and patterned on a substrate such as a glass substrate, a flexible substrate, or a semiconductor substrate. At this time, a series of layers such as a dielectric layer and a metal layer are deposited on the substrate by a process such as chemical vapor deposition (CVD) or physical vapor deposition (PVD).

[0003] In order to form these layers uniformly, it is necessary to heat the substrate to a uniform temperature, and a substrate heating device may be used to heat and support the substrate. The substrate heating device may be used for heating the substrate in an etching process of a dielectric layer or a metal layer formed on the substrate, a firing process of a photo resistor, and the like.

[0004] A ceramic heater used as such a substrate heating device includes a heating element and a thermocouple for measuring the temperature of the heating element. The thermocouple is inserted into a thermocouple passage formed inside the ceramic heater, but heat generated by the heating element may be released through the thermocouple passage. When such heat loss occurs, it leads to a problem that the temperature uniformity of the substrate disposed on the ceramic heater decreases.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The problem to be solved is to prevent heat loss due to a passage into which a temperature sensor such as a thermocouple is inserted.

[0006] Another problem to be solved is to prevent cracks from occurring in the plate of the ceramic heater due to the expansion and contraction of the heating element.

[0007] Another problem to be solved is to measure the temperature of the heating element more accurately.

[0008] Another problem to be solved is to freely select the position where a temperature sensor such as a thermocouple is installed to increase the design freedom.

Means for Solving the Problems

[0009] The ceramic heater according to an embodiment of the present invention includes a plate having a heating element and a first passage; and a shaft having a hollow, wherein the heating element includes a plurality of concentric arc portions and a plurality of connecting portions connecting the arc portions, and a separation region formed by the plurality of connecting portions facing each other at a predetermined distance is extended in the radial direction of the plate, and the first passage provides a ceramic heater formed adjacent to the separation region.

Effects of the Invention

[0010] According to an embodiment of the present invention, by arranging the passage into which the temperature sensor is inserted in a region where the heating element is not dense, heat loss and cracks in the ceramic plate can be prevented.

[0011] Also, by arranging the temperature measuring portion of the temperature sensor near the heating element, the temperature of the heating element can be measured more accurately.

[0012] Also, by installing the temperature sensor inside the wall portion of the shaft, the design freedom with respect to the position of the temperature sensor can be increased.

Brief Description of the Drawings

[0013]

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Best Mode for Carrying Out the Invention

[0014] Hereinafter, with reference to the accompanying drawings, the embodiments disclosed in this specification will be described in detail. However, regardless of the reference numerals in the drawings, the same or similar components are given the same reference numerals, and redundant descriptions thereof are omitted. Hereinafter, in the description of the embodiments according to the present invention, when it is described that each layer (film), region, pattern, or structure is formed "on / above" or "under / below" a substrate, each layer (film), region, pad, or pattern, "on / above" and "under / below" include both being formed "directly" or "indirectly via another layer". Also, "on / above" or "under / below" each layer is described with reference to the drawings. In the drawings, the thickness and size of each layer are exaggerated, omitted, or schematically shown for the sake of convenience and clarity of explanation. Note that the size of each component does not fully reflect the actual size.

[0015] In this description, expressions such as "including", "comprising", or "configured to" are for representing a certain characteristic, number, step, operation, element, part thereof, or combination, and should not be construed as excluding the existence or possibility of one or more other characteristics, numbers, steps, operations, elements, part thereof, or combinations other than those described.

[0016] Also, terms such as first, second, etc. may be used to describe various components, but these components are not limited by the terms such as first, second, etc., and these terms are only used for the purpose of distinguishing one component from another.

[0017] Also, when explaining the embodiments disclosed in this specification, if it is determined that a specific description of related known technologies may obscure the gist of the embodiments disclosed in this specification, the detailed description thereof is omitted.

[0018] The attached drawings are only for facilitating the easy understanding of the embodiments disclosed in this specification, and the technical idea disclosed in this specification shall not be limited by the attached drawings. It should be understood that the present invention includes any modifications, equivalents or alternatives included in the idea and technical scope of the present invention.

[0019] Hereinafter, various embodiments of the present invention will be described in detail with reference to the drawings.

[0020] FIG. 1 is a perspective view of a ceramic heater according to an embodiment of the present invention.

[0021] The ceramic heater 10 is a device that supports various objects to be heat-treated, such as semiconductor wafers, glass substrates, flexible substrates, etc., and heats the object to be heat-treated to a predetermined temperature.

[0022] The ceramic heater 10 is composed of a plate 20 on which an object to be heat-treated, such as a semiconductor wafer W, is placed, and a shaft 50 coupled to the lower surface 20b of the plate. The plate 20 includes a flat mounting surface (first surface) 20a on which the object to be heat-treated is placed, and a lower surface (second surface) 20b to which the shaft 50 is coupled.

[0023] The plate 20 is a disk-shaped plate 20 containing a ceramic material such as aluminum nitride or alumina. The shaft 50 may be formed of a ceramic material such as aluminum nitride or alumina, similar to the plate 20.

[0024] FIG. 2 is a cross-sectional view taken horizontally along the heating element of the plate according to an embodiment of the present invention as seen from above, FIG. 3 is a cross-sectional view taken horizontally along the heating element of the plate according to still another embodiment of the present invention as seen from above, and FIG. 4 is a partially enlarged view showing the P portion of FIG. 2.

[0025] Referring to FIGS. 2 to 4, the plate 20 is formed of a ceramic material, Al 2 O 3 , Y 2 O 3, Al 2 O 3 / Y 2 O 3 、ZrO 2 、AlC, TiN, AlN, TiC, MgO, CaO, CeO 2 、TiO 2 、B x C y 、BN, SiO 2 、SiC, YAG, Mullite, AlF 3 Any one of these, or two or more of them may be used in combination.

[0026] The plate 20 may include a heating element 23. The heating element 23 has a function of heating an object to be heat-treated located on the mounting surface 20a of the plate to a constant temperature so that vapor deposition processes and etching processes can be smoothly performed in semiconductor manufacturing processes and the like.

[0027] The heating element 23 may be embedded in the plate 20 corresponding to the position of the object to be heat-treated. In order to uniformly heat the object to be heat-treated as a whole by heat generation, the heating element 23 can uniformly control the heating temperature according to the position, and in addition, the distance of heat transfer to the object to be heat-treated is kept constant at almost all positions, so that it may be embedded in the plate 20 parallel to the mounting surface 20a of the plate.

[0028] The heating element 23 may be formed in a shape corresponding to the shape of the object to be heat-treated. Further, the heating element 23 may be formed in a plate-like coil form or a flat plate form by a heating wire (or resistance wire). The heating element 23 may be formed of tungsten (W), molybdenum (Mo), molybdenum carbide (Mo 2 C, MoC, Mo 3 C 2 ), silver (Ag), gold (Au), platinum (Pt), niobium (Nb), titanium (Ti) or an alloy thereof. The heating element 23 may be electrically connected to the terminals 21 and 22 by a conductive connection portion 28.

[0029] At the center of the plate 20, a pair of first terminals 21 and a pair of second terminals 22 may be formed. The first terminal 21 electrically connects the internal zone heating element 24 formed in the internal region of the plate 20 and a rod described later, and the second terminal 22 electrically connects the external zone heating element 25 formed in the external region of the plate 20 and the rod.

[0030] In the present invention, the heating element 23 may be composed of two or more heating elements in order to heat a plurality of partitioned zones. Exemplarily, FIG. 2 shows a heating element 23 composed of an internal zone heating element 24 and an external zone heating element 25 for partitioning a plate into an internal zone and an external zone and heating each zone. Hereinafter, a heater partitioned into an internal zone and an external zone will be described, but the present invention is not limited thereto. For example, it goes without saying that the present invention can also be applied to a multi-zone heater in which a plate of a ceramic heater is partitioned into a fan shape at a predetermined angle and includes heating elements corresponding to the partitioned regions.

[0031] The internal zone heating element 24 starts from the first terminal 21a, is continuously wired in the internal region of the plate 20 while forming a constant pattern like concentric circles, and is then connected to the first terminal 21b. In this process, the internal zone heating element 24 can form a plurality of concentric circle pattern shapes while bending at a plurality of connecting portions 23'.

[0032] The plurality of concentric circle patterns of the internal zone heating element 24 may include a plurality of concentric arc portions 24a-1, 24a-2, 24b-1, 24b-2 extending along the circumferential direction of the plate 20. Further, it may include a plurality of connecting portions 23' that connect adjacent arc portions 24a-1, 24a-2, 24b-1, 24b-2 among the plurality of concentric arc portions 24a-1, 24a-2, 24b-1, 24b-2. The adjacent arc portions 24a-1, 24a-2, 24b-1, 24b-2 may be connected by a connecting portion 23' extending in the diameter direction.

[0033] The plurality of concentric arc portions 24a-1, 24a-2, 24b-1, 24b-2 may have different diameters. Also, the plurality of connecting portions 23' may be aligned parallel to each other, and a separation region 26 extending in the radial direction of the plate 20 can be formed in the plate 20 between them.

[0034] The internal zone heating element 24 may include a first internal heating portion 24a and a second internal heating portion 24b. The first internal heating portion 24a and the second internal heating portion 24b may form a line-symmetric structure about the diameter direction of the plate 20 and may be connected to each other.

[0035] The arc portion 24a-1 of the first internal heating portion 24a and the arc portion 24b-1 of the second internal heating portion 24b are arc portions of the same diameter. The arc portion 24a-2 of the first internal heating portion 24a and the arc portion 24b-2 of the second internal heating portion 24b are also arc portions of the same diameter and are arc portions with a larger diameter than the arc portion 24a-1 and the arc portion 24b-1. The arc portion 24a-1 is connected to the arc portion 24a-2 by the connecting portion 23'. The arc portion 24b-1 is connected to the arc portion 24b-2 by the connecting portion 23'.

[0036] The connecting portion 23' of the first internal heating portion 24a and the connecting portion 23' of the second internal heating portion 24b may be arranged facing each other with a certain distance E therebetween. A separation region 26 where the internal zone heating element 24 is not wired may be formed in the plate 20 within the region formed by the virtual line I formed by the separated connecting portions 23'. The separation region 26 may extend in the radial direction of the plate 20.

[0037] The separation region 26 may be formed between the first internal heating portion 24a and the second internal heating portion 24b, and preferably, may be formed within the region formed by the plurality of connecting portions 23' aligned parallel to each other and extending in the radial direction of the plate 20. The separation region 26 may be formed in the circumferential direction from the central portion of the plate 20.

[0038] The external zone heating element 25 starts from the second terminal 22a, is continuously wired in the external region of the plate 20 while forming a concentric circular pattern, and is then connected to the second terminal 22b. In this process, the external zone heating element 25 can form a concentric circular pattern while bending at a fixed position in a form surrounding the internal zone heating element 24 (see Fig. 2), or can form a plurality of concentric circular patterns while bending at a plurality of connecting portions 23' (see Fig. 3).

[0039] The plurality of concentric circular patterns of the external zone heating element 25 may include a plurality of concentric arc portions 25a-1, 25a-2, 25b-1, 25b-2 extending along the circumferential direction of the plate 20. Further, it may include a plurality of connecting portions 23' connecting adjacent arc portions 25a-1, 25a-2, 25b-1, 25b-2 among the plurality of concentric arc portions 25a-1, 25a-2, 25b-1, 25b-2. The adjacent arc portions 25a-1, 25a-2, 25b-1, 25b-2 may be connected by a connecting portion 23' extending in the diameter direction.

[0040] The plurality of concentric arc portions 25a-1, 25a-2, 25b-1, 25b-2 may have different diameters. Also, the plurality of connecting portions 23' are aligned parallel to each other, and a separation region 26 extending in the radial direction of the plate 20 can be formed in the plate 20 between them.

[0041] The external zone heating element 25 may include a first external heating portion 25a and a second external heating portion 25b. The first external heating portion 25a and the second external heating portion 25b form a line-symmetric structure centered on the diameter direction of the plate 20 and may be connected to each other.

[0042] The arc portion 25a-1 of the first external heating part 25a and the arc portion 25b-1 of the second external heating part 25b are arc portions of the same diameter. The external zone heating element 25 may further include an arc portion 25a-2 of the first external heating part 25a and an arc portion 25b-2 of the second external heating part 25b. The arc portion 25a-2 and the arc portion 25b-2 are arc portions of the same diameter, and are arc portions with a larger diameter than the arc portion 25a-1 and the arc portion 25b-1. The arc portion 25a-1 is connected to the arc portion 25a-2 by a connecting portion 23'. The arc portion 25b-1 is connected to the arc portion 25b-2 by a connecting portion 23'.

[0043] The connecting portion 23' of the first external heating part 25a and the connecting portion 23' of the second external heating part 25b may be arranged facing each other with a certain distance E therebetween. A separation region 26 in which the external zone heating element 25 is not wired may be formed on the plate 20 within the region formed by an imaginary line I formed by the separated connecting portions 23'. The separation region 26 may extend in the radial direction of the plate 20.

[0044] The separation region 26 may be formed between the first external heating part 25a and the second external heating part 25b, and preferably, may be formed within a region formed by a plurality of connecting portions 23' being aligned parallel to each other and extending in the radial direction of the plate 20. Also, the separation region 26 may be formed between a conductive connection portion 28 connected to the second terminal 22a and a conductive connection portion 28 connected to the second terminal 22b. The separation region 26 may be formed by extending from the separation region 26 formed in the inner region in the circumferential direction from the central portion of the plate 20.

[0045] The inner zone heating element 24 and the external zone heating element 25 may be electrically separated and driven independently of each other.

[0046] A first passage 27 into which a temperature sensor 60 such as a thermocouple is inserted may be formed in the plate 20. The first passage 27 may be formed along the separation region 26 so as to be adjacent to the separation region 26. Also, the first passage 27 may be formed parallel to the mounting surface 20a of the plate.

[0047] As shown in FIGS. 2 to 4, when viewed in the thickness direction of the plate 20 from above the plate 20, the first passage 27 may be formed adjacent to the separation region 26 so as not to overlap the heating element 23. Further, the first passage 27 may be formed adjacent to the separation region 26 formed between the conductive connection portion 28 connected to the second terminal 22a and the conductive connection portion 28 connected to the second terminal 22b.

[0048] As shown in FIGS. 2 and 3, a plurality of heating elements, for example, two heating elements 24 and 25, may be arranged independently of each other on the plate 20, or as shown in FIG. 5, one single heating element 23 may be arranged in all regions of the plate 20.

[0049] FIG. 6 is a cross-sectional view taken along the line C-C of FIG. 2.

[0050] Referring to FIG. 6, since the first passage 27 is formed adjacent to and along the separation region 26, as shown in FIG. 6, the heating element 23 does not have to be arranged above the first passage 27. By forming the first passage 27 in a region where the heating elements 23 are not concentrated, it is possible to prevent the heat generated by the heating elements 23 from being lost through the first passage 27, and to improve the temperature uniformity of the heater. Further, it is possible to prevent cracks from occurring in the vulnerable portions of the plate 20 due to the expansion and contraction of the heating elements 23.

[0051] On the other hand, FIGS. 7 and 8 are diagrams showing that heat loss and microcracks occur when the first passage is formed in a region where the heating elements are concentrated.

[0052] As shown in FIG. 7, when the first passage 27 is formed adjacent to the heating element 23, the heat generated by the heating element 23 may be lost through the first passage 27.

[0053] Further, as shown in FIG. 8, when the first passage 27 is formed adjacent to the heating element 23, microcracks may occur in the thin portions of the plate 20 due to the expansion and contraction of the heating element 23.

[0054] FIG. 9 is a C-C cross-sectional view of a plate according to still another embodiment of the present invention.

[0055] A temperature sensor 60 such as a thermocouple is inserted into the first passage 27 of the plate 20. The first passage 27 may be composed of a first A passage portion 27a formed parallel to the mounting surface 20a of the plate and a first B passage portion 27b inclined with respect to the mounting surface 20a.

[0056] The first B passage portion 27b is disposed at the circumferential end of the first passage 27, and the temperature measuring portion of the temperature sensor 60 may be located there. By forming the first B passage portion 27b to incline toward the heating element 23, the distance between the temperature measuring portion of the temperature sensor 60 and the heating element 23 can be minimized. Further, by positioning the circumferential end of the first B passage portion 27b at the same height as the heating element, that is, on the same plane in the thickness direction of the plate, the temperature of the region between the heating element connecting portions 23' can be measured more accurately.

[0057] FIG. 10 is a diagram for explaining the process of manufacturing the plate of FIG. 9, FIG. 11 is a partially enlarged view showing the Z portion of FIG. 9, and FIG. 12 is a cross-sectional view taken in the E-E direction of FIG. 11.

[0058] The plate 20 may be composed of an upper plate P2 and a lower plate P1. The first B passage portion 27b may be formed in the upper plate P2, and the first A passage portion 27a may be formed in the lower plate P1.

[0059] The first A passage portion 27a and the first B passage portion 27b may be in the form of grooves or holes extending long in the circumferential direction of the plate 20 so that a temperature sensor 60 such as a thermocouple can be inserted. The first A passage portion 27a and the first B passage portion 27b may have various cross-sectional forms such as circular and square.

[0060] The plate 20 may be manufactured by joining a lower plate P1 and an upper plate P2 in which a first passage portion 27a and a second passage portion 27b are formed. At this time, if the first passage portion 27a and the second passage portion 27b are not accurately aligned, the space through which the temperature sensor 60 can pass will decrease, making it difficult or impossible to insert the temperature sensor 60 into the second passage portion 27b.

[0061] As shown in FIG. 11, the second passage portion 27b can be processed into a shape such as a polyhedron like a cone, triangular pyramid, or square pyramid, a frustum of a cone, or a frustum of a polyhedron so that the upper plate P2 and the lower plate P1 can be easily aligned when joined. In this way, by forming the cross-sectional area of the end portion of the second passage portion 27b to be small, the temperature measuring portion of the thermocouple inserted into the second passage portion 27b does not sway, and the temperature measurement accuracy can be improved.

[0062] When the upper plate P2 and the lower plate P1 are joined, an outlet of the first passage portion 27a, which is a hole through which the temperature sensor 60 can pass, may be formed at one end of the first passage portion 27a formed in the lower plate P1. Further, an inlet of the second passage portion 27b, which is a hole through which the temperature sensor 60 can pass, may be located at a position in contact with the outlet of the first passage portion 27a.

[0063] By the outlet of the first passage portion 27a and the inlet of the second passage portion 27b being in contact, the first passage portion 27a and the second passage portion 27b can integrally form the first passage 27. At this time, in order to prevent the space through which the temperature sensor 60 passes from decreasing even if the first passage portion 27a and the second passage portion 27b are not accurately aligned, the inlet area D2 of the second passage portion 27b can be formed to be larger than the outlet area D1 of the first passage portion 27a.

[0064] Also, by positioning the margin space of the inlet area D2 of the second passage portion 27b, that is, the space corresponding to (D2 - D1), in a direction away from the center of the plate 20, a temperature sensor such as a thermocouple can be easily inserted into the second passage portion 27b. That is, the thermocouple inserted through the first passage portion 27a can be easily inserted along the inner wall of the second passage portion 27b without hitting the upper plate P2 at the inlet of the second passage portion 27b.

[0065] Also, the second passage portion 27b may be formed in a form in which the cross-sectional area decreases in a direction away from the center of the plate 20.

[0066] In this way, by forming the inlet area D2 of the second passage portion 27b to be larger than the outlet area D1 of the first passage portion 27a, when assembling the plate 22, it is possible to assemble while allowing an alignment error in the radial direction (the left - right direction in FIG. 10) of the plate 22. Also, as shown in FIG. 12, by forming the width of the first passage portion 27a to be larger than the width of the second passage portion 27b, it is also possible to assemble the plate 22 while allowing an alignment error in the rotational direction (the circumferential direction of the plate).

[0067] FIG. 13 is a cross - sectional view taken along the line B - B of FIG. 1.

[0068] The shaft 50 may be formed of a wall portion 51 having a predetermined thickness and may be formed in a cylindrical shape having a space (hollow) inside. A plurality of rods 61a, 61b, 62a, 62b connected to the terminals of the plate may be installed in the internal space of the shaft 50.

[0069] A temperature sensor 60 such as a thermocouple may be inserted into the first passage 27 of the plate 20 through the hollow 55 of the shaft.

[0070] FIG. 14 is a cross - sectional view taken along the line A - A of FIG. 1 to which the shaft according to an embodiment of the present invention is applied, and FIG. 15 is a cross - sectional view taken along the line D - D of FIG. 14.

[0071] The shaft 50 may be formed in a cylindrical shape having a space inside. A plurality of rods 61a, 61b, 62a, 62b connected to the terminals of the plate may be installed in the internal space of the shaft 50.

[0072] The shaft 50 may be formed of a wall portion 51 having a predetermined thickness. Inside the wall portion 51, a second passage 52, which is a passage into which a temperature sensor 60 such as a thermocouple is inserted, may be formed extending along the longitudinal direction of the wall portion 51. Since the second passage 52 is connected to the first passage 27, the temperature sensor 60 can be inserted into the first passage 27 through the second passage 52.

[0073] The wall portion 51 may be composed of a first thickness portion 51a having a first thickness X and a second thickness portion 51b having a second thickness Y. The second thickness may be greater than the first thickness. The second passage 52 may be formed within the thickness of the wall portion 51, and preferably, may be formed within the thicker second thickness portion 51b.

[0074] The second thickness portion 51b is a wall portion 51 formed thicker than the first thickness portion 51a, and preferably, may be formed to protrude outside the wall portion 51.

[0075] The second passage 52 may be formed in the number required for the temperature sensors 60. FIG. 16 shows a state in which four second thickness portions 51b are formed and the second passage 52 is formed in each second thickness portion 51b. As shown in FIG. 16, when four second passages 52 are formed, four first passages 27 may also be formed in the plate 20. At this time, each first passage 27 and the second passage 52 are connected to each other, and each temperature sensor 60 may be inserted into the first passage 27 through the second passage 52.

[0076] FIG. 17 is a plan view of a ceramic heater according to still another embodiment of the present invention, and is a diagram for explaining the arrangement of the first passage and the second passage.

[0077] The ceramic heater 10 shown in Fig. 17 is provided with six first passages 27 and six second passages 52 respectively. Six second thickness portions 51b are formed on the shaft 50, and second passages 52 are formed in the respective second thickness portions 51b. Each second passage 52 is connected in correspondence with the six first passages 27 formed in the plate 20.

[0078] As described in the explanations of Figs. 16 and 17, when there are a plurality of first passages 27, a plurality of separation regions 26 may also be formed. That is, when four or six first passages 27 are formed, four or six separation regions 26 in which the respective first passages 27 are arranged adjacent to each other may be formed respectively.

[0079] Also, when there are a plurality of first passages 27, as shown in Fig. 17, some of the first passages 27 may be formed up to the intermediate position of the ceramic plate 20. In this case, the temperature measuring portions of the temperature sensor 60 are located at different distances from the center portion of the plate 20 and can measure the temperature. Fig. 18 is a cross-sectional view taken along the line B-B of Fig. 1 to which the shaft according to the embodiment of the present invention is applied.

[0080] A plurality of rods 61a, 61b, 62a, 62b connected to the terminals of the plate 20 are installed in the internal space of the shaft 50. Since the second passage 52 according to the embodiment of the present invention is located within the thickness of the shaft wall portion 51, the second passage 52 can be formed regardless of the positions of the terminals 21a, 21b, 22a, 22b or the rods 61a, 61b, 62a, 62b.

[0081] The second passage 52 formed in the wall portion 51 of the shaft 50 is connected to the first passage 27 of the plate 20. Therefore, as shown in Fig. 19, the temperature sensor 60 can be inserted into the second passage 52 and the first passage 27.

[0082] As described above, in the present invention, specific matters such as specific components, limited embodiments, and drawings have been described. However, this is only provided to assist in a more general understanding of the present invention, and the present invention is not limited to the above embodiments. Those with ordinary knowledge in the field to which the present invention pertains can make various modifications and variations without departing from the essential characteristics of the present invention. Therefore, the idea of the present invention should not be defined only by the described embodiments, and not only the scope of the following claims, but also any technical ideas with modifications equivalent or equivalent to this scope of claims should be interpreted as being included in the scope of rights of the present invention. Also, each of the above embodiments can be used in combination with each other as necessary.

Explanation of Reference Numerals

[0083] 10 Ceramic heater 20 Plate 23 Heating element 26 Separation region 27 First passage 27a First A passage portion 27b First B passage portion 50 Shaft 51 Wall portion 51a First thickness portion 51b Second thickness portion 52 Second passage

Claims

1. a plate having a heating element and a first passage; a shaft having a hollow, the heating element includes a plurality of concentric arc portions and a plurality of connecting portions connecting the arc portions, a separation region formed by the plurality of connecting portions facing each other at a predetermined distance extends in a radial direction of the plate, The first passage is a ceramic heater formed adjacent the separation region.

2. The ceramic heater of claim 1 , wherein the plurality of connectors are aligned parallel to one another and define spaced apart regions extending in a radial direction of the plate.

3. the plate includes a first heating portion and a second heating portion connected to the first heating portion and symmetrical to the first heating portion; The ceramic heater according to claim 1 , wherein the separation region is formed between the first heat generating portion and the second heat generating portion.

4. The ceramic heater according to claim 1 , wherein the first passages do not overlap the heating element in a thickness direction of the plate.

5. The ceramic heater according to claim 1 , wherein the isolation region and the first passage are each a plurality of regions.

6. The ceramic heater according to claim 5 , wherein the plurality of first passages includes at least two of the first passages having different lengths.

7. the shaft includes a wall and a second passageway; The ceramic heater according to claim 1 , wherein the second passage is formed in the wall along a longitudinal direction of the wall.

8. the wall portion includes a first thickness portion having a first thickness and a second thickness portion having a second thickness; The second thickness is greater than the first thickness; The ceramic heater of claim 7 , wherein the second passages are formed within the second thickness.

9. The ceramic heater according to claim 8 , wherein the second thick portion is formed to protrude outward from the wall portion.

10. the wall portion includes a first thickness portion having a first thickness and a plurality of second thickness portions having a second thickness; The second thickness is greater than the first thickness; a plurality of the second passages formed in the plurality of second thickness portions, The separation region and the first passage are each a plurality of regions, The ceramic heater according to claim 7 , wherein a plurality of the second passages correspond to a plurality of the first passages, respectively.

11. 2. The ceramic heater of claim 1, wherein the first passages include a passage portion A parallel to the first surface of the plate and a passage portion B inclined relative to the first surface.

12. the plate includes a first plate portion and a second plate portion; The ceramic heater of claim 11 , wherein the A passage portion is located in the first plate portion and the B passage portion is located in the second plate portion.

13. The ceramic heater according to claim 11 , wherein the B passage portion is inclined toward the heating element.

14. The ceramic heater according to claim 13 , wherein the B passage portion is located at an end in a circumferential direction of the first passage.

15. The ceramic heater according to claim 11, wherein an outlet area of ​​the A passage portion is smaller than an inlet area of ​​the B passage portion.

16. The ceramic heater further comprises a thermocouple; the thermocouple is located within the first passage and the second passage; The ceramic heater according to claim 13 , wherein the temperature measuring portion of the thermocouple is located in the B passage portion.

17. The ceramic heater further comprises a thermocouple; The ceramic heater according to any one of claims 1 to 6 and 11 to 16, wherein the thermocouple is located within the hollow of the shaft and within the second passage.

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