Ceramic heater

Abstract

The present invention relates to a two-zone heating element embedded in a ceramic heater, comprising first and second heating sections which can be independently controlled by a power supply; a first non-heating section which is disposed between first and second sub-heating sections constituting the first heating section and electrically connects the first and second sub-heating sections; and a second non-heating section which is disposed between the second heating section and a first electrode terminal and electrically connects the second heating section and the first electrode terminal.

Description

Technical Field

[0001] The present invention relates to a ceramic heater, and more specifically, to a ceramic heater with improved reliability.

Background Art

[0002] A ceramic heater is used to heat various objects to be heat-treated, such as semiconductor wafers, glass substrates, and flexible substrates, to a predetermined heating temperature. Generally, a ceramic heater includes a heater body portion composed of a ceramic plate and a heater support portion attached to the lower portion of the heater body portion, and the heater body portion includes a heating element having a predetermined resistance. The temperature distribution on the heating surface of the ceramic heater can be adjusted by the arrangement and design of the heating elements embedded in the ceramic plate, and the temperature distribution on the heating surface of the ceramic heater may be adjusted by changes such as the interval between the heating elements, the shape of the heating elements, the material of the heating elements, and the thickness of the heating elements.

[0003] The temperature distribution formed on the heating surface of the ceramic heater may be variously required depending on the properties of the object to be heat-treated. At this time, when designing a ceramic heater using only one heating element, various temperature distributions can be realized by changing the embedding interval, embedding shape, material, and thickness of the heating element embedded in the ceramic heater. However, due to the property that the ceramic plate of the ceramic heater has high thermal conductivity, there is a problem that it is difficult to uniformly realize various temperature distributions required for each region depending on the properties of the object to be heat-treated by heating elements controlled with the same power. For this reason, in recent years, a ceramic heater in which two or more heating elements capable of independent control are embedded has been proposed.

[0004] FIG. 1 is a diagram illustrating the structure of a 2-zone heating element embedded in a conventional ceramic heater. As shown in FIG. 1, the conventional 2-zone heating element 10 includes a first heating portion 11, a second heating portion 12, and a non-heating portion 13.

[0005] The first electrode terminal 20 and the second electrode terminal 30 are embedded in the ceramic plate corresponding to the central portion of the heating element 10. The first electrode terminal 20 contacts the lower surface of the heating element 10 and serves to electrically connect the first heating portion 11 of the heating element 10 and a first heating element rod (not shown). The second electrode terminal 30 contacts the lower surface of the heating element 10 and serves to electrically connect the non-heating portion 13 of the heating element 10 and a second heating element rod (not shown).

[0006] The first heating portion 11 is formed at a position corresponding to the inner zone of the heating surface of the ceramic heater, and the second heating portion 12 is formed at a position corresponding to the outer zone of the heating surface of the ceramic heater. The first and second heating portions 11 and 12 are arranged at a certain distance from each other. Also, the first and second heating portions 11 and 12 are electrically separated from each other and are driven independently of each other.

[0007] The non-heating portion 13 is disposed between the second electrode terminal 30 and the second heating portion 12 and serves to electrically connect the second electrode terminal 30 and the second heating portion 12. The non-heating portion 13 is formed to extend from the central point of the heating surface of the ceramic heater toward the periphery. Also, the non-heating portion 13 is formed in a linear structure having a length of usually 100 mm to 120 mm.

[0008] However, in the conventional two-zone heating element 10, in the process of sintering / heat treatment, due to the difference in the coefficient of thermal expansion between the aluminum nitride material constituting the ceramic plate and the metal material constituting the non-heating portion 13, there has been a problem that crack phenomena occur at various positions within the section where the ceramic plate and the non-heating portion 13 contact. In order to solve such a problem, a solution for shortening the length of the non-heating portion 13 is required. Summary of the Invention Problems to be Solved by the Invention

[0009] The present invention aims to solve the above-described problems and other problems. Still another object is to provide a ceramic heater with improved reliability.

[0010] Still another object is to provide a ceramic heater with improved temperature uniformity.

[0011] Still another object is to provide a ceramic heater in which a multi-zone heating element including two or more heat-generating parts capable of independent control and two or more non-heat-generating parts connected to the heat-generating parts is embedded.

[0012] Still another object is to provide a ceramic heater in which a multi-zone heating element including two or more non-heat-generating parts with a shorter linear length compared to the conventional one is embedded.

Means for Solving the Problems

[0013] To achieve the above or other objects, according to one aspect of the present invention, a first and a second heat-generating part capable of independent control by a power supply device; a first non-heat-generating part disposed between a first and a second sub-heat-generating parts constituting the first heat-generating part and electrically connecting the first and second sub-heat-generating parts; and a second non-heat-generating part disposed between the second heat-generating part and a first electrode terminal and electrically connecting the second heat-generating part and the first electrode terminal; a ceramic heater in which a 2-zone heating element including these is embedded is provided.

[0014] According to another aspect of the present invention, a first to a fourth heat-generating part capable of independent control by a power supply device; a first and a second non-heat-generating part disposed opposite to each other with respect to a first symmetry axis between the first heat-generating part and the second heat-generating part and disposed at a certain distance from the center of the 4-zone heating element; and a third and a fourth non-heat-generating part disposed opposite to each other with respect to a second symmetry axis between the third heat-generating part and the fourth heat-generating part and extending in the direction of the third and fourth heat-generating parts from the first and second electrode terminals disposed at the center of the 4-zone heating element; a ceramic heater in which a 4-zone heating element including these is embedded is provided.

[0015] According to still another aspect of the present invention, there is provided a ceramic heater in which a 6-zone heating element is embedded, the ceramic heater including: first to sixth heating parts that can be independently controlled by a power supply device; first to third non-heating parts that are arranged at a certain distance from the center of the 6-zone heating element and are arranged at an angle of 120° with respect to the center of the 6-zone heating element; and fourth to sixth non-heating parts that extend from first to third electrode terminals arranged at the center of the 6-zone heating element in the direction of the fourth to sixth heating parts and are arranged at an angle of 120° with respect to the center of the 6-zone heating element.

Advantages of the Invention

[0016] According to at least one of the embodiments of the present invention, by providing a 2-zone heating element including two non-heating parts with a shorter linear length compared to the prior art, it is possible to reduce the thermal stress caused by the non-heating parts, and thereby effectively reduce the occurrence of cracks in the section where the non-heating parts contact the ceramic plate.

[0017] Also, according to at least one of the embodiments of the present invention, by providing a 4-zone heating element including four non-heating parts with a shorter linear length compared to the prior art, it is possible to reduce the thermal stress caused by the non-heating parts, and thereby effectively reduce the occurrence of cracks in the section where the non-heating parts contact the ceramic plate.

[0018] Also, according to at least one of the embodiments of the present invention, by providing a 6-zone heating element including six non-heating parts with a shorter linear length compared to the prior art, it is possible to reduce the thermal stress caused by the non-heating parts, and thereby effectively reduce the occurrence of cracks in the section where the non-heating parts contact the ceramic plate.

[0019] However, the effects that can be achieved by the ceramic heater according to the embodiments of the present invention are not limited to those mentioned above. Other effects not mentioned will be clearly understood by those with ordinary knowledge in the technical field to which the present invention pertains from the following description.

Brief Description of the Drawings

[0020]

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Figure 10

Modes for Carrying Out the Invention

[0021] 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 will be assigned the same reference numbers, and redundant descriptions thereof will be omitted. In the following description of the embodiments according to the present invention, when it is described that each layer (film), region, pattern, or structure is formed "on" or "under" a substrate, each layer (film), region, pad, or pattern, it may include any case where it is formed "directly" or "indirectly via another layer" "on" or "under". Also, the reference for "on" or "under" 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. Also, the size of each component does not fully reflect the actual size.

[0022] 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 will be omitted. Also, the accompanying drawings are merely for facilitating the understanding of the embodiments disclosed in this specification, and the technical idea disclosed in this specification is not limited by the accompanying drawings, and should be understood to include any modifications, equivalents, or alternatives included in the idea and technical scope of the present invention.

[0023] The present invention proposes a ceramic heater with improved reliability. Also, the present invention proposes a ceramic heater with improved temperature uniformity. Also, the present invention proposes a ceramic heater in which a multi-zone heating element including two or more heat-generating parts capable of independent control and two or more non-heat-generating parts connected to the two or more heat-generating parts is embedded. Also, the present invention proposes a ceramic heater in which a multi-zone heating element including two or more non-heat-generating parts with a shortened linear length compared to the conventional one is embedded.

[0024] Hereinafter, various embodiments of the present invention will be described in detail with reference to the drawings.

[0025] FIG. 2 is a perspective view showing the outer shape of a ceramic heater according to an embodiment of the present invention, and FIG. 3 is a cross-sectional view showing the configuration of the ceramic heater according to an embodiment of the present invention.

[0026] Referring to FIGS. 2 and 3, a ceramic heater 100 according to an embodiment of the present invention is a semiconductor device that supports various objects to be heat-treated, such as semiconductor wafers, glass substrates, and flexible substrates, and heats the object to be heat-treated at a predetermined temperature.

[0027] The ceramic heater 100 may include a heater body portion 110 that transfers heat while stably holding an object to be heat-treated (not shown), and a heater support portion 120 attached to the lower portion of the heater body portion 110. On the other hand, although not shown, an adhesive layer (not shown) may be formed between the heater body portion 110 and the heater support portion 120.

[0028] The heater body portion 110 may be formed of a plate-like structure having a predetermined shape. As an example, the heater body portion 110 may be formed of a circular plate-like structure, but is not necessarily limited thereto.

[0029] A pocket region (or cavity region, 111) having a structure recessed by a predetermined step may be formed on the upper portion of the heater body portion 110 so that an object to be heat-treated, such as a wafer, can be stably mounted. The upper surface of the heater body portion 110 corresponding to the pocket region may be formed to have excellent flatness. This is to ensure that the object to be heat-treated installed in the chamber is horizontally arranged without tilting to one side.

[0030] The heater body portion 110 may be composed of a plurality of ceramic plates (not shown) formed of a ceramic material having excellent thermal conductivity, and may be formed by performing a compression sintering process on the plurality of ceramic plates. Here, the ceramic material is Al 2 O 3 、Y 2O 3 、 Al 2 O 3 / Y 2 O 3 、 ZrO 2 、 AlC (Autoclaved lightweight concrete), TiN, AlN, TiC, MgO, CaO, CeO 2 、 TiO 2 、 B x C y 、 BN, SiO 2 、 SiC, YAG, ムライト (Mullite), AlF 3 may be at least one of these substances, and more preferably may be aluminum nitride (AlN).

[0031] The heater body portion 110 may include a heating element 112 and a plurality of electrode terminals 113, 114 that contact the lower surface of the heating element 112. On the other hand, although not shown, the heater body portion 110 may include a high-frequency electrode for performing an RF (Radio Frequency) grounding function and / or an electrostatic chuck function.

[0032] The heating element 112 may have a function of heating an object to be heat-treated located on the upper surface of the heater body portion 110 at a constant temperature in order to perform a smooth deposition process and an etching process in a semiconductor manufacturing process.

[0033] The heating element 112 may be embedded in the heater body portion 110 corresponding to the position of the object to be heat-treated. The heating element 112 may not only uniformly control the heating temperature depending on the position in order to uniformly heat the object to be heat-treated as a whole, but also be embedded in the heater body portion 110 in parallel with the object to be heat-treated so that the distance through which heat is transferred to the object to be heat-treated is maintained constant at almost all positions.

[0034] The heating element 112 may be formed in a shape corresponding to the shape of the object to be heat-treated. Also, the heating element 112 may be formed in a plate-shaped coil form or a flat plate form by a heating wire (or, resistance wire).

[0035] The heating element 112 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.

[0036] In particular, the heating element 112 according to the present embodiment may be a multi-zone heating element including two or more heat generating portions capable of independent control and two or more non-heat generating portions connected to the two or more heat generating portions. The heating element 112 may be provided with two or more non-heat generating portions having a shorter linear length than conventional ones, thereby effectively reducing the thermal stress caused by the non-heat generating portions.

[0037] The plurality of electrode terminals 113 and 114 may contact the lower surface of the heating element 112 and may have a function of electrically connecting the heat generating portion of the heating element 112 and the plurality of heating element rods 121 and 122.

[0038] The plurality of electrode terminals 113 and 114 may be embedded in a ceramic plate corresponding to the central portion of the heating element 112, that is, the portion where the heater body portion 110 and the heater support portion 120 contact.

[0039] The plurality of electrode terminals 113 and 114 may be formed of a metal material having excellent electrical conductivity. As an example, the plurality of electrode terminals 113 and 114 may be formed of tungsten (W), molybdenum (Mo), silver (Ag), gold (Au), niobium (Nb), titanium (Ti), aluminum nitride (AlN) or an alloy thereof, and more preferably, may be formed of molybdenum (Mo).

[0040] The heater support portion 120 is mounted below the heater body portion 110 and can play a role of supporting the heater body portion 110. The heater support portion 120 can be combined with the heater body portion 110 to constitute a ceramic heater 100 having an overall T shape.

[0041] The heater support part 120 may be formed in the form of a cylindrical tube having an empty space inside. This is for installing a plurality of heating element rods 121 and 122 that are connected to the heating element 112 of the heater body part 110 through the heater support part 120.

[0042] The heater support part 120 may be formed of the same ceramic material as the main component of the heater body part 110. For example, the heater support part 120 is Al 2 O 3 、Y 2 O 3 、Al 2 O 3 / Y 2 O 3 、ZrO 2 、AlC (Autoclaved lightweight concrete), TiN, AlN, TiC, MgO, CaO, CeO 2 、TiO 2 、B x C y 、BN, SiO 2 、SiC, YAG, Mullite, AlF 3 and may be formed of at least one of these substances, and more preferably, may be formed of aluminum nitride (AlN).

[0043] The plurality of heating element rods 121 and 122 are installed inside the heater support part 120 and may have a function of electrically connecting the plurality of electrode terminals 113 and 114 and an external power supply device (not shown). Thereby, the heating part of the heating element 112 embedded in the heater body part 110 may be electrically connected to the external power supply device through the plurality of electrode terminals 113 and 114 and the heating element rods 121 and 122, and independent control is possible by the external power supply device.

[0044] The plurality of heating element rods 121 and 122 may be formed of a metal material having excellent electrical conductivity. For example, the plurality of heating element rods 121 and 122 may be formed of copper (Cu), aluminum (Al), iron (Fe), tungsten (W), nickel (Ni), silver (Ag), gold (Au), niobium (Nb), titanium (Ti), or an alloy thereof, and more preferably, may be formed of nickel (Ni).

[0045] On the other hand, in the figure, although it is illustrated that two electrode terminals 113 and 114 and two heating element rods 121 and 122 are installed in the ceramic heater 100, it is not necessarily limited thereto. The number of electrode terminals and heating element rods installed in the ceramic heater corresponds to the number of heat generating portions that can be independently controlled by an external power supply device.

[0046] As described above, the ceramic heater according to an embodiment of the present invention includes a multi-zone heating element including two or more non-heating portions having a shorter straight length compared to the conventional one, thereby reducing the thermal stress caused by the non-heating portions. Accordingly, the generation of cracks in the section where the non-heating portion and the ceramic plate are in contact can be effectively reduced.

[0047] FIG. 4 is a diagram showing the structure of a 2-zone heating element according to an embodiment of the present invention, FIG. 5 is a diagram showing the detailed structure of the elements constituting the 2-zone heating element of FIG. 4, and FIG. 6 is a diagram showing an enlarged view of part A of FIG. 4.

[0048] Referring to FIGS. 4 to 6, a 2-zone heating element 200 according to an embodiment of the present invention may include first and second heat generating portions 210 and 220 and first and second non-heating portions 230 and 240.

[0049] The first heat generating portion (center / edge heat generating portion) 210 may include a first sub-heat generating portion (center heat generating portion) 211 and a second sub-heat generating portion (edge heat generating portion) 213. Here, the first and second sub-heat generating portions 211 and 213 may be electrically connected through the first non-heating portion 230.

[0050] The first sub-heating part 211 may be formed at a position corresponding to the center zone of the ceramic heater heating surface. The first sub-heating part 211 may be formed in a circular shape.

[0051] The first sub-heating part 211 may include a plurality of concentric circumferences 211a and a plurality of connecting parts 211b connecting the plurality of concentric circumferences 211a. A first end portion located inside the first sub-heating part 211 may be connected to the second electrode terminal 114, and a second end portion located outside may be connected to the first non-heating part 230.

[0052] The second sub-heating part 213 may be formed at a position corresponding to the edge zone of the ceramic heater heating surface. The second sub-heating part 213 may be formed in an annular shape.

[0053] The second sub-heating part 213 may include a plurality of concentric circumferences 213a and a plurality of connecting parts 213b connecting the plurality of concentric circumferences 213a. An end portion existing inside the second sub-heating part 213 may be connected to the first non-heating part 230.

[0054] The second heating part (middle heating part) 220 may be formed at a position corresponding to the middle zone of the ceramic heater heating surface. That is, the second heating part 220 may be formed so as to be disposed in the space between the first sub-heating part 211 and the second sub-heating part 213. The second heating part 220 may be formed in an annular shape.

[0055] The second heating part 220 may include a plurality of concentric circumferences 220a and a plurality of connecting parts 220b connecting the plurality of concentric circumferences 220a. An end portion located inside the second heating part 220 may be connected to the second non-heating part 240.

[0056] The first and second heating parts 210 and 220 may be disposed on the same plane of the ceramic plate. On the other hand, as another embodiment, the first and second heating parts 210 and 220 may be disposed on different planes from each other.

[0057] The first non-heating part 230 is disposed between the first sub-heating part 211 and the second sub-heating part 213, and may have a function of electrically connecting the first and second sub-heating parts 211 and 213. The first non-heating part 230 may be formed to extend linearly from a point of the first sub-heating part 211 to a point of the second sub-heating part 213.

[0058] On the other hand, although not shown in the drawings, as another embodiment, the first non-heating part 230 may be formed to extend in a curved shape from a point of the first sub-heating part 211 to a point of the second sub-heating part 213. As still another embodiment, the first non-heating part 230 may be formed to extend in a form in which a straight line and a curve are combined from a point of the first sub-heating part 211 to a point of the second sub-heating part 213.

[0059] The first end of the first non-heating part 230 may be connected to the second end located outside the first sub-heating part 211, and the second end of the first non-heating part 230 may be connected to the end located inside the second sub-heating part 213. At this time, as shown in FIG. 6(a), the first non-heating part 230 may be connected to the second sub-heating part 213 through the first connecting member 250. The first connecting member 250 may be configured to include an opening for press-fitting and fixing wires having different diameters that constitute the first non-heating part 230 and the second sub-heating part 213. On the other hand, as another embodiment, the first non-heating part 230 may be directly connected to the second sub-heating part 213 without another connecting member as shown in FIG. 6(b).

[0060] The first non-heating part 230 may include two metal wires arranged in parallel with each other. The first non-heating part 230 may be formed such that the axis of symmetry between the two metal wires crosses the center of the heating element 200.

[0061] The first non-heating part 230 may be formed to have a straight-line length shorter than the straight-line length of the non-heating part included in the conventional two-zone heating element. As an example, when the straight-line length of the conventional non-heating part is 100 mm to 120 mm, the first non-heating part 230 may be formed to have a straight-line length corresponding to about 60% of the conventional length (60 mm to 70 mm).

[0062] The first non-heating part 230 may be formed to have a first length shorter than or equal to the straight-line length between a point of the second sub-heating part 213 and the second electrode terminal 114.

[0063] The second non-heating part 240 may be disposed between the first electrode terminal 113 and the second heating part 220 and may have a function of electrically connecting the first electrode terminal 113 and the second heating part 220. The second non-heating part 240 may be formed to extend linearly from the first electrode terminal 113 to a point of the second heating part 220.

[0064] On the other hand, although not shown in the drawings, as another embodiment, the second non-heating part 240 may be formed to extend curvilinearly from the first electrode terminal 113 to a point of the second heating part 220. As still another embodiment, the second non-heating part 240 may be formed to extend in a form in which a straight line and a curve are combined from the first electrode terminal 113 to a point of the second heating part 220.

[0065] The first end of the second non-heating part 240 may be connected to the first electrode terminal 113, and the second end of the second non-heating part 240 may be connected to an end portion located inside the second heating part 220. At this time, the second non-heating part 240 may be connected to the second heating part 220 through the second connecting member 260 as shown in FIG. 6(a). Similarly, the second connecting member 260 may be configured to include an opening for press-fitting and fixing wires having different diameters that constitute the second non-heating part 240 and the second heating part 220. On the other hand, as another embodiment, the second non-heating part 240 may be directly connected to the second heating part 220 without another connecting member as shown in FIG. 6(b).

[0066] The second non-heating part 240 may include two metal wires arranged in parallel to each other. The second non-heating part 240 may be formed such that the axis of symmetry between both metal wires crosses the center of the heating element 200.

[0067] The second non-heating part 240 may be arranged in a direction facing the first non-heating part 230 with respect to the center of the heating element 200. The first and second non-heating parts 230 and 240 may be arranged on a straight line crossing the center of the heating element 200, and more preferably, may be arranged on a horizontal line crossing the center of the heating element 200.

[0068] The second non-heating part 240 may be formed to have the same straight-line length as that of the first non-heating part 230 or a different straight-line length. The second non-heating part 240 may be formed to have a straight-line length shorter than the straight-line length of the non-heating part included in the conventional 2-zone heating element. As an example, when the straight-line length of the conventional non-heating part is 100 mm to 120 mm, the second non-heating part 240 may be formed to have a straight-line length corresponding to about 60% (60 mm to 70 mm) compared to the conventional length.

[0069] The second non-heating part 240 may be formed to have a second length shorter than or equal to the straight-line length between a point of the second sub-heating part 213 and the first electrode terminal 113.

[0070] The first and second heating parts 210 and 220, the first and second non-heating parts 230 and 240, and the first and second connecting members 250 and 260 may all be made of the same material, but are not necessarily limited thereto.

[0071] As described above, the two-zone heating element according to an embodiment of the present invention includes two non-heating portions with a shorter linear length compared to the prior art, thereby reducing the thermal stress caused by the non-heating portions, and thus effectively reducing the occurrence of cracks in the section where the non-heating portions contact the ceramic plate. Further, the two-zone heating element can independently control two regions of the heating surface of the ceramic heater and implement various temperature distributions, thereby improving the temperature uniformity of the heating surface of the ceramic heater.

[0072] FIG. 7 is a diagram showing the structure of a four-zone heating element according to an embodiment of the present invention, and FIG. 8 is a diagram showing the detailed structure of the elements constituting the four-zone heating element of FIG. 7.

[0073] Referring to FIGS. 7 and 8, the four-zone heating element 300 according to an embodiment of the present invention may include first to fourth heating portions 310 to 340 and first to fourth non-heating portions 350 to 380.

[0074] The first heating portion 310 may include a first sub-heating portion 311 and a second sub-heating portion 313. Here, the first and second sub-heating portions 311 and 313 may be electrically connected through the first non-heating portion 350.

[0075] The second heating portion 320 may include a third sub-heating portion 321 and a fourth sub-heating portion 323. Here, the third and fourth sub-heating portions 321 and 323 may be electrically connected through the second non-heating portion 360.

[0076] The first and second heating portions 310 and 320 may be formed in a symmetric shape with respect to a horizontal axis crossing the center of the heating element 300. Further, the first and second heating portions 310 and 320 may be arranged to face each other with respect to a horizontal axis crossing the center of the heating element 300.

[0077] The first and third sub-heating portions 311 and 321 may be formed at positions corresponding to the center zone of the ceramic heater heating surface. The first and third sub-heating portions 311 and 321 may include a plurality of concentric circumferences 311a and 321a, and a plurality of connecting portions 311b and 321b connecting the plurality of concentric circumferences 311a and 321a.

[0078] The first and third sub-heating portions 311 and 321 may be formed to have the same shape as each other. For example, the first and third sub-heating portions 311 and 321 may be formed in a semi-circular shape.

[0079] The first end of the first sub-heating portion 311 may be connected to the third electrode terminal 115, and the second end may be connected to the first non-heating portion 350. The first end of the third sub-heating portion 321 may be connected to the fourth electrode terminal 116, and the second end may be connected to the second non-heating portion 360.

[0080] The second and fourth sub-heating portions 313 and 323 may be formed at positions corresponding to the edge zone of the ceramic heater heating surface. The second and fourth sub-heating portions 313 and 323 may include a plurality of concentric circumferences 313a and 323a, and a plurality of connecting portions 313b and 323b connecting the plurality of concentric circumferences 313a and 323a.

[0081] The second and fourth sub-heating portions 313 and 323 may be formed to have the same shape as each other. For example, the second and fourth sub-heating portions 313 and 323 may be formed in a semi-annular shape.

[0082] The end of the second sub-heating portion 313 may be connected to the first non-heating portion 350. The end of the fourth sub-heating portion 323 may be connected to the second non-heating portion 360.

[0083] The third and fourth heating parts 330 and 340 may be formed at positions corresponding to the middle zone of the ceramic heater heating surface. Further, the third heating part 330 may be formed to be disposed in the space between the first and third sub - heating parts 311 and 321 and the second and fourth sub - heating parts 313 and 323. The fourth heating part 340 may be formed to be disposed in the space between the first and third sub - heating parts 311 and 321 and the second and fourth sub - heating parts 313 and 323. The fourth heating part 340 may be formed in a semi - annular shape.

[0084] The third and fourth heating parts 330 and 340 may be formed in shapes that are symmetric with each other with respect to a vertical axis crossing the center of the heating element 300. Also, the third and fourth heating parts 330 and 340 may be arranged to face each other with respect to a vertical axis crossing the center of the heating element 300.

[0085] The third and fourth heating parts 330 and 340 may be formed to have the same shape as each other. For example, the third and fourth heating parts 330 and 340 may be formed in a semi - annular shape.

[0086] The third and fourth heating parts 330 and 340 may include a plurality of concentric circumferences 330a and 340a and a plurality of connecting parts 330b and 340b connecting the plurality of concentric circumferences 330a and 340a.

[0087] The first to fourth heating parts 310 to 340 may be disposed on the same plane of the ceramic plate. On the other hand, as another embodiment, at least one of the first to fourth heating parts 310 to 340 may be disposed on different planes from each other.

[0088] The first non - heating part 350 is disposed between the first sub - heating part 311 and the second sub - heating part 313 and may have a function of electrically connecting the first and second sub - heating parts 311 and 313. The first non - heating part 350 may be formed to extend linearly from a point of the first sub - heating part 311 to a point of the second sub - heating part 313.

[0089] The first non-heating part 350 may be connected to the second sub-heating part 313 through a connecting member (not shown). On the other hand, as another embodiment, the first non-heating part 350 may be directly connected to the second sub-heating part 313 without another connecting member.

[0090] The second non-heating part 360 is disposed between the third sub-heating part 321 and the fourth sub-heating part 323, and may have a function of electrically connecting the third and fourth sub-heating parts 321, 323. The second non-heating part 360 may be formed to extend linearly from a point of the third sub-heating part 321 to a point of the fourth sub-heating part 323.

[0091] The second non-heating part 360 may be connected to the fourth sub-heating part 323 through a connecting member (not shown). On the other hand, as another embodiment, the second non-heating part 360 may be directly connected to the fourth sub-heating part 323 without another connecting member.

[0092] The first and second non-heating parts 350, 360 may include two metal wires arranged in parallel with each other. The first and second non-heating parts 350, 360 may be formed such that the symmetry axis between both metal wires crosses the center of the heating element 300.

[0093] The first and second non-heating parts 350, 360 may be formed to have a linear length shorter than the linear length of the non-heating part included in the conventional 4-zone heating element. For example, when the linear length of the conventional non-heating part is 100 mm to 120 mm, the first and second non-heating parts 350, 360 may be formed to have a linear length (60 mm to 70 mm) corresponding to about 60% compared to the conventional length.

[0094] The first non-heating part 350 may be formed to have a first length shorter than or equal to the linear length between a point of the second sub-heating part 313 and the third electrode terminal 115, and the second non-heating part 360 may be formed to have a first length shorter than or equal to the linear length between a point of the fourth sub-heating part 323 and the fourth electrode terminal 116.

[0095] The first and second non-heating portions 350 and 360 may be arranged to face each other with respect to a horizontal axis crossing the center of the heating element 300. That is, the first and second non-heating portions 350 and 360 may be arranged to face each other with respect to the symmetry axis between the first heating portion 310 and the second heating portion 320. The first and second non-heating portions 350 and 360 may be arranged at a certain distance from the center of the heating element 300.

[0096] The first and second non-heating portions 350 and 360 may be arranged on a straight line crossing the center of the heating element 300, and more preferably, may be arranged on a vertical line crossing the center of the heating element 300.

[0097] The third non-heating portion 370 is arranged between the first electrode terminal 113 and the third heating portion 330, and may have a function of electrically connecting the first electrode terminal 113 and the third heating portion 330. The third non-heating portion 370 may be formed to extend linearly from the first electrode terminal 113 to a point of the third heating portion 330.

[0098] The third non-heating portion 370 may be connected to the third heating portion 330 through a connecting member (not shown). On the other hand, as another embodiment, the third non-heating portion 370 may be directly connected to the third heating portion 330 without another connecting member.

[0099] The fourth non-heating portion 380 is arranged between the second electrode terminal 114 and the fourth heating portion 340, and may have a function of electrically connecting the second electrode terminal 114 and the fourth heating portion 340. The fourth non-heating portion 380 may be formed to extend linearly from the second electrode terminal 114 to a point of the fourth heating portion 340.

[0100] The fourth non-heating portion 380 may be connected to the fourth heating portion 340 through a connecting member (not shown). On the other hand, as another embodiment, the fourth non-heating portion 380 may be directly connected to the fourth heating portion 340 without another connecting member.

[0101] The third and fourth non-heating portions 370 and 380 may include two metal wires arranged in parallel with each other. The third and fourth non-heating portions 370 and 380 may be formed such that the axis of symmetry between both metal wires crosses the center of the heating element 300.

[0102] The third and fourth non-heating portions 370 and 380 may be formed to have a straight-line length shorter than the straight-line length of the non-heating portions included in the conventional 4-zone heating element. For example, when the straight-line length of the conventional non-heating portion is 100 mm to 120 mm, the third and fourth non-heating portions 370 and 380 may be formed to have a straight-line length (60 mm to 70 mm) corresponding to about 60% of the conventional length.

[0103] The third non-heating portion 370 may be formed to have a second length shorter than or equal to the straight-line length between a point of either one of the second sub-heating portion 313 and the fourth sub-heating portion 323 and the first electrode terminal 113, and the fourth non-heating portion 380 may be formed to have a second length shorter than or equal to the straight-line length between a point of either one of the second sub-heating portion 313 and the fourth sub-heating portion 323 and the second electrode terminal 114. The third and fourth non-heating portions 370 and 380 may be formed to have the same straight-line length as or a different straight-line length from the straight-line lengths of the first and second non-heating portions 350 and 360.

[0104] The third and fourth non-heating portions 370 and 380 may be arranged to face each other with respect to a vertical axis crossing the center of the heating element 300. That is, the third and fourth non-heating portions 370 and 380 may be arranged to face each other with respect to the axis of symmetry between the third heating portion 330 and the fourth heating portion 340. Also, the third and fourth non-heating portions 370 and 380 may be arranged on a straight line crossing the center of the heating element 300, and more preferably, may be arranged on a horizontal line crossing the center of the heating element 300.

[0105] On the one hand, in this embodiment, it is exemplified that the first to fourth non-heating portions 350 to 380 are formed to extend linearly. However, it is not necessarily limited thereto. It will be apparent to those skilled in the art that instead of the linear shape, it may be formed to extend in a curved shape or in a form in which a straight line and a curve are combined.

[0106] The first to fourth heating portions 310 to 340, the first to fourth non-heating portions 350 to 380, and the first to fourth connecting members (not shown) may all be made of the same material, and are not necessarily limited thereto.

[0107] As described above, the 4-zone heating element according to an embodiment of the present invention includes four non-heating portions with a shortened straight-line length compared to the prior art, thereby reducing the thermal stress caused by the non-heating portions. As a result, the occurrence of cracks in the section where the non-heating portion contacts the ceramic plate can be effectively reduced. In addition, the 4-zone heating element can improve the temperature uniformity of the heating surface of the ceramic heater by independently controlling four regions of the heating surface of the ceramic heater to implement various temperature distributions.

[0108] FIG. 9 is a diagram showing the structure of a 6-zone heating element according to an embodiment of the present invention, and FIG. 10 is a diagram showing the detailed structure of the elements constituting the 6-zone heating element of FIG. 9.

[0109] Referring to FIGS. 9 and 10, a 6-zone heating element 400 according to an embodiment of the present invention may include first to sixth heating portions 410 to 460 and first to sixth non-heating portions 510 to 560.

[0110] The first heating portion 410 may include a first sub-heating portion 411 and a second sub-heating portion 413. Here, the first and second sub-heating portions 411 and 413 may be electrically connected through the first non-heating portion 510.

[0111] The second heating part 420 may include a third sub - heating part 421 and a fourth sub - heating part 423. Here, the third and fourth sub - heating parts 421, 423 may be electrically connected through a second non - heating part 520.

[0112] The third heating part 430 may include a fifth sub - heating part 431 and a sixth sub - heating part 433. Here, the fifth and sixth sub - heating parts 431, 433 may be electrically connected through a third non - heating part 530.

[0113] The first, third, and fifth sub - heating parts 411, 421, 431 may be formed at positions corresponding to the center zone of the ceramic heater heating surface. The first, third, and fifth sub - heating parts 411, 421, 431 may include a plurality of concentric circumferences 411a, 421a, 431a and a plurality of connecting parts 411b, 421b, 431b connecting the plurality of concentric circumferences 411a, 421a, 431a.

[0114] The first, third, and fifth sub - heating parts 411, 421, 431 may be formed to have the same shape as each other. For example, the first, third, and fifth sub - heating parts 411, 421, 431 may be formed in a fan shape.

[0115] The first end of the first sub - heating part 411 may be connected to the fourth electrode terminal 116, and the second end may be connected to the first non - heating part 510. The first end of the third sub - heating part 421 may be connected to the fifth electrode terminal 117, and the second end may be connected to the second non - heating part 520. The first end of the fifth sub - heating part 431 may be connected to the sixth electrode terminal 118, and the second end may be connected to the third non - heating part 530.

[0116] The second, fourth, and sixth sub - heating parts 413, 423, 433 may be formed at positions corresponding to the edge zone of the ceramic heater heating surface. The second, fourth, and sixth sub - heating parts 413, 423, 433 may include a plurality of concentric circumferences 413a, 423a, 433a and a plurality of connecting parts 413b, 423b, 433b connecting the plurality of concentric circumferences 413a, 423a, 433a.

[0117] The second, fourth, and sixth sub-heating portions 413, 423, and 433 may be formed to have the same shape as each other. For example, the second, fourth, and sixth sub-heating portions 413, 423, and 433 may be formed in an annular shape divided into three equal parts.

[0118] An end portion of the second sub-heating portion 413 may be connected to the first non-heating portion 510. An end portion of the fourth sub-heating portion 423 may be connected to the second non-heating portion 520. An end portion of the sixth sub-heating portion 433 may be connected to the third non-heating portion 530.

[0119] The fourth to sixth heating portions 440 to 460 may be formed at positions corresponding to an intermediate region (middle zone) of the ceramic heater heating surface. Further, the fourth heating portion 440 may be formed to be disposed in a space between the first and third sub-heating portions 411, 421 and the second and fourth sub-heating portions 413, 423. The fifth heating portion 450 may be formed to be disposed in a space between the third and fifth sub-heating portions 421, 431 and the fourth and sixth sub-heating portions 423, 433. The sixth heating portion 460 may be formed to be disposed in a space between the first and fifth sub-heating portions 411, 431 and the second and sixth sub-heating portions 413, 433.

[0120] The fourth to sixth heating portions 440 to 460 may be formed to have the same shape as each other. For example, the fourth to sixth heating portions 440 to 460 may be formed in an annular shape divided into three equal parts.

[0121] The fourth to sixth heating portions 440 to 460 may include a plurality of concentric circumferences 440a, 450a, 460a and a plurality of connecting portions 440b, 450b, 460b connecting the plurality of concentric circumferences 440a, 450a, 460a.

[0122] The first to sixth heating portions 410 to 460 may be disposed on the same plane of the ceramic plate. On the other hand, as another embodiment, at least one of the first to sixth heating portions 410 to 460 may be disposed on different planes from each other.

[0123] The first non-heating part 510 is disposed between the first sub-heating part 411 and the second sub-heating part 413, and may have a function of electrically connecting the first and second sub-heating parts 411 and 413. The first non-heating part 510 may be formed to extend linearly from a point of the first sub-heating part 411 to a point of the second sub-heating part 413.

[0124] The first non-heating part 510 may be connected to the second sub-heating part 413 through a connecting member (not shown). On the other hand, as another embodiment, the first non-heating part 510 may be directly connected to the second sub-heating part 413 without another connecting member.

[0125] The second non-heating part 520 is disposed between the third sub-heating part 421 and the fourth sub-heating part 423, and may have a function of electrically connecting the third and fourth sub-heating parts 421 and 423. The second non-heating part 520 may be formed to extend linearly from a point of the third sub-heating part 421 to a point of the fourth sub-heating part 423.

[0126] The second non-heating part 520 may be connected to the fourth sub-heating part 423 through a connecting member (not shown). On the other hand, as another embodiment, the second non-heating part 520 may be directly connected to the fourth sub-heating part 423 without another connecting member.

[0127] The third non-heating part 530 is disposed between the fifth sub-heating part 431 and the sixth sub-heating part 433, and may have a function of electrically connecting the fifth and sixth sub-heating parts 431 and 433. The third non-heating part 530 may be formed to extend linearly from a point of the fifth sub-heating part 431 to a point of the sixth sub-heating part 433.

[0128] The third non-heating part 530 may be connected to the sixth sub-heating part 433 through a connecting member (not shown). On the other hand, as another embodiment, the third non-heating part 530 may be directly connected to the sixth sub-heating part 433 without another connecting member.

[0129] The first to third non-heating parts 510 to 530 may include two metal wires arranged in parallel to each other. The first to third non-heating parts 510 to 530 may be formed such that the symmetry axis between the two metal wires crosses the center of the heating element 400.

[0130] The first to third non-heating parts 510 to 530 may be formed to have a linear length shorter than the linear length of the non-heating parts included in the conventional 6-zone heating element. For example, when the linear length of the conventional non-heating part is 100 mm to 120 mm, the first to third non-heating parts 510 to 530 may be formed to have a linear length (60 mm to 70 mm) corresponding to about 60% compared to the conventional length.

[0131] The first non-heating part 510 may be formed to have a first length shorter than or equal to the linear length between a point of the second sub-heating part 413 and the fourth electrode terminal 116. The second non-heating part 520 may be formed to have a first length shorter than or equal to the linear length between a point of the fourth sub-heating part 423 and the fifth electrode terminal 117. The third non-heating part 530 may be formed to have a first length shorter than or equal to the linear length between a point of the sixth sub-heating part 433 and the sixth electrode terminal 118.

[0132] The first to third non-heating parts 510 to 530 may be formed to form an angle of 120° with each other with respect to the center of the heating element 400. Also, the first to third non-heating parts 510 to 530 may be arranged at a certain distance from the center of the heating element 400. Also, the first to third non-heating parts 510 to 530 may be formed to have the same linear length as each other.

[0133] The fourth non-heating part 540 is arranged between the first electrode terminal 113 and the fourth heating part 440, and may have a function of electrically connecting the first electrode terminal 113 and the fourth heating part 440. The fourth non-heating part 540 may be formed to extend linearly from the first electrode terminal 113 to a point of the fourth heating part 440.

[0134] The fourth non-heating part 540 may be connected to the fourth heating part 440 through a connecting member (not shown). On the other hand, as another embodiment, the fourth non-heating part 540 may be directly connected to the fourth heating part 440 without another connecting member.

[0135] The fifth non-heating part 550 is disposed between the second electrode terminal 114 and the fifth heating part 450, and may have a function of electrically connecting the second electrode terminal 114 and the fifth heating part 450. The fifth non-heating part 550 may be formed to extend linearly from the second electrode terminal 114 to a point of the fifth heating part 450.

[0136] The fifth non-heating part 550 may be connected to the fifth heating part 450 through a connecting member (not shown). On the other hand, as another embodiment, the fifth non-heating part 550 may be directly connected to the fifth heating part 450 without another connecting member.

[0137] The sixth non-heating part 560 is disposed between the third electrode terminal 115 and the sixth heating part 460, and may have a function of electrically connecting the third electrode terminal 115 and the sixth heating part 460. The sixth non-heating part 560 may be formed to extend linearly from the third electrode terminal 115 to a point of the sixth heating part 460.

[0138] The sixth non-heating part 560 may be connected to the sixth heating part 460 through a connecting member (not shown). On the other hand, as another embodiment, the sixth non-heating part 560 may be directly connected to the sixth heating part 460 without another connecting member.

[0139] The fourth to sixth non-heating parts 540 to 560 may include two metal wires arranged in parallel with each other. The fourth to sixth non-heating parts 540 to 560 may be formed such that the symmetry axis between both metal wires crosses the center of the heating element 400.

[0140] The fourth to sixth non-heating portions 540 to 560 may be formed to have a linear length shorter than the linear length of the non-heating portions included in the conventional six-zone heating element. For example, when the linear length of the conventional non-heating portion is 100 mm to 120 mm, the fourth to sixth non-heating portions 540 to 560 may be formed to have a linear length (60 mm to 70 mm) corresponding to about 60% of the conventional length.

[0141] The fourth non-heating portion 540 may be formed to have a second length shorter than or equal to the linear length between one point of any one of the second, fourth, and sixth sub-heating portions 413, 423, 433 and the first electrode terminal 113. The fifth non-heating portion 550 may be formed to have a second length shorter than or equal to the linear length between one point of any one of the second, fourth, and sixth sub-heating portions 413, 423, 433 and the second electrode terminal 114. The sixth non-heating portion 560 may be formed to have a second length shorter than or equal to the linear length between one point of any one of the second, fourth, and sixth sub-heating portions 413, 423, 433 and the third electrode terminal 115. The fourth to sixth non-heating portions 540 to 560 may be formed to have the same linear length as or a different linear length from the linear lengths of the first to third non-heating portions 510 to 530.

[0142] The fourth to sixth non-heating portions 540 to 560 may be formed to form an angle of 120° with each other with respect to the center of the heating element 400. Also, the fourth to sixth non-heating portions 540 to 560 may be formed to have the same linear length as each other.

[0143] On the other hand, in this embodiment, it is exemplified that the first to sixth non-heating portions 510 to 560 are formed to extend linearly, but it is not necessarily limited thereto. It will be apparent to those skilled in the art that instead of the linear shape, they may be formed to extend in a curved shape, or may be formed to extend in a form in which a straight line and a curve are combined.

[0144] The first to sixth heating portions 410 to 460, the first to sixth non-heating portions 510 to 560, and the first to sixth connecting members (not shown) may all be made of the same material, but are not necessarily limited thereto.

[0145] As described above, the 6-zone heating element according to an embodiment of the present invention includes six non-heating portions with a shortened linear length compared to the prior art, so that the thermal stress caused by the non-heating portions can be reduced. Thereby, the generation of cracks in the section where the non-heating portion contacts the ceramic plate can be effectively reduced. Further, the 6-zone heating element can improve the temperature uniformity of the heating surface of the ceramic heater by independently controlling six regions of the heating surface of the ceramic heater to implement various temperature distributions.

[0146] On the other hand, although the specific embodiments of the present invention have been described above, it is needless to say that various modifications can be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims described below and other equivalents to the scope of these claims.

Claims

1. A ceramic heater including a two-zone heating element and first and second electrode terminals disposed at a central portion of the two-zone heating element, wherein the two-zone heating element, first and second heating portions capable of being independently controlled by a power supply device, a first non-heating portion disposed between first and second sub-heating portions constituting the first heating portion and electrically connecting the first and second sub-heating portions, a second non-heating portion disposed between the second heating portion and the first electrode terminal and electrically connecting the second heating portion and the first electrode terminal, and the first electrode terminal is in contact with one end of the second non-heating portion, and the second electrode terminal is in contact with the first heating portion. A ceramic heater characterized by this.

2. The first sub-heating portion is formed at a position corresponding to a central region (center zone) of the heating surface of the ceramic heater, The second sub-heating portion is formed at a position corresponding to an edge region (edge zone) of the heating surface of the ceramic heater. The ceramic heater according to claim 1, characterized by this.

3. The second heating portion is formed at a position corresponding to an intermediate region (middle zone) of the heating surface of the ceramic heater. The ceramic heater according to claim 2, characterized by this.

4. The first non-heating portion is formed to extend linearly or curvilinearly from a point of the first sub-heating portion to a point of the second sub-heating portion, The second non-heating portion is formed to extend linearly or curvilinearly from the first electrode terminal to a point of the second heating portion. The ceramic heater according to claim 1, characterized by this.

5. The first non-heating portion is connected to the second sub-heating portion through a first connecting member (connector), The second non-heating portion is connected to the second heating portion through a second connecting member. The ceramic heater according to claim 1, characterized by this.

6. The first and second non-heating portions are disposed on a straight line crossing the center of the two-zone heating element. The ceramic heater according to claim 1, characterized by this.

7. The first and second non-heating portions are disposed opposite to each other with respect to the center of the two-zone heating element. The ceramic heater according to claim 1, characterized by this.

8. The first and second non-heating parts include two metal wires arranged in parallel with each other, and are formed such that the axis of symmetry between the two metal wires crosses the center of the two-zone heating element. The ceramic heater according to claim 1.

9. A ceramic heater including a four-zone heating element, wherein the four-zone heating element includes first to fourth heating parts that can be independently controlled by a power supply device, first and second non-heating parts that are arranged opposite to each other with reference to a first axis of symmetry between the first heating part and the second heating part, and are arranged at a certain distance from the center of the four-zone heating element, first and second non-heating parts that are arranged opposite to each other with reference to a second axis of symmetry between the third heating part and the fourth heating part, and extend from the first and second electrode terminals arranged at the center of the four-zone heating element in the directions of the third and fourth heating parts, wherein the first non-heating part is arranged between the first and second sub-heating parts that constitute the first heating part, and the second non-heating part is arranged between the third and fourth sub-heating parts that constitute the second heating part. The ceramic heater is characterized by this.

10. The second axis of symmetry is perpendicular to the first axis of symmetry. The ceramic heater according to claim 9.

11. The first and second axes of symmetry pass through the center of the four-zone heating element. The ceramic heater according to claim 9.

12. The first non-heating part electrically connects the first and second sub-heating parts, and the second non-heating part electrically connects the third and fourth sub-heating parts. The ceramic heater according to claim 9.

13. The third non-heating part is arranged between the third heating part and the first electrode terminal, and electrically connects the third heating part and the first electrode terminal, and the fourth non-heating part is arranged between the fourth heating part and the second electrode terminal, and electrically connects the fourth heating part and the second electrode terminal. The ceramic heater according to claim 9.

14. Each of the first to fourth non-heating parts is formed to extend linearly or in a curved shape. The ceramic heater according to claim 9.

15. Each of the first to fourth non-heating parts is connected to the first to fourth heating parts through connecting members. The ceramic heater according to claim 9.

16. A ceramic heater including a six-zone heating element, The 6-zone heating element is a first to sixth heating part that can be independently controlled by a power supply device, a first to third non-heating parts that are arranged at a certain distance from the center of the 6-zone heating element and are arranged at an angle of 120° with respect to the center of the 6-zone heating element, a fourth to sixth non-heating parts that are extended from the first to third electrode terminals arranged at the center of the 6-zone heating element in the direction of the fourth to sixth heating parts and are arranged at an angle of 120° with respect to the center of the 6-zone heating element, and includes a ceramic heater, wherein the first non-heating part is arranged between the first and second sub-heating parts that constitute the first heating part, the second non-heating part is arranged between the third and fourth sub-heating parts that constitute the second heating part, and the third non-heating part is arranged between the fifth and sixth sub-heating parts that constitute the third heating part.

17. The first non-heating part electrically connects the first and second sub-heating parts, The second non-heating part electrically connects the third and fourth sub-heating parts, The ceramic heater according to claim 16, wherein the third non-heating part electrically connects the fifth and sixth sub-heating parts.

18. The fourth non-heating part is arranged between the fourth heating part and the first electrode terminal and electrically connects the fourth heating part and the first electrode terminal, The fifth non-heating part is arranged between the fifth heating part and the second electrode terminal and electrically connects the fifth heating part and the second electrode terminal, The ceramic heater according to claim 16, wherein the sixth non-heating part is arranged between the sixth heating part and the third electrode terminal and electrically connects the sixth heating part and the third electrode terminal.

19. The ceramic heater according to claim 16, wherein the first to sixth non-heating parts are each formed to extend linearly or in a curved shape.

20. The ceramic heater according to claim 16, wherein the first to sixth non-heating parts are each connected to the first to sixth heating parts through a connecting member.

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