JP2004134238A - Sheet ceramic heater and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet ceramic heater superior in temperature uniformity within surface. <P>SOLUTION: This is the sheet ceramic heater constructed of a heating element circuit 3 wiring formed on the ceramic substrate 2 and a heating object mounting side surface ceramic layer arranged on its surface. The heating object mounting side surface ceramic layer is made of two layers of ceramic layers 4, 5 and a temperature equalizer layer 5 clipped by these. This temperature equalizer layer 5 can be formed by using a material having superior heat conductivity such as tungsten, and can be formed by paste printing method or pasting of a foil, board, or mesh or the like. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a planar heater formed of ceramics and a method of manufacturing the same, and more particularly, to a planar ceramic heater suitable for use in heating a silicon wafer and a method of manufacturing the same.
[0002]
[Prior art]
AlN ceramics are widely used as a heater for heating a wafer in a semiconductor manufacturing apparatus because they have excellent thermal characteristics such as high thermal conductivity and high thermal shock resistance and corrosion resistance to fluorine plasma. As the shape, there is a shape in which a heating element is sandwiched between two ceramic layers, or a shape in which a heating element layer is formed on a ceramic base layer (see Patent Document 1).
[0003]
As a manufacturing method, a method is known in which a heating element circuit is constructed on a ceramic base substrate green sheet laminate having a predetermined thickness, and a heater cover portion having a predetermined thickness is laminated thereon by sheet molding. I have. In this method, to form a heating element and an electrode, a method of forming a conductive paste by screen printing is generally used. A power supply connection terminal of the heater heating element is provided on the laminated body thus formed, and the heater is obtained by degreasing under a predetermined condition and sintering at a predetermined temperature by a hot press or the like.
[0004]
As another method, there is known a method in which a heating element circuit is formed on a sintered body base material, a sintered body is arranged on the surface of the heating element circuit, a bonding agent is applied, and then a hot press is used for joining. As a method of forming the heating element and the electrodes in this case, there is a method such as screen printing of a conductive paste or embedding a metal plate or mesh processed into a wiring shape (see Patent Document 2).
[0005]
In general, a planar ceramic heater, in which a heating element wiring pattern is formed at the same width and the same pitch on the inner and outer periphery of the planar ceramic heater, heat is easily dissipated from the outer peripheral portion, and a temperature gradient occurs in the surface, The stress may cause breakage of the heater.
[0006]
In order to avoid this, in order to make the in-plane temperature distribution of the planar ceramic heater uniform, (1) the distance between the heating element wirings on the outer peripheral portion is made closer, (2) the resistance value is changed, (3) It is conceivable to take countermeasures such as forming another heating element wiring circuit in the outer peripheral portion and the central portion, and (4) separately controlling the temperature of the outer peripheral portion and the central portion of the heating element.
[0007]
However, with the recent demand for larger heaters and higher temperatures due to larger wafer diameters and higher heat treatment temperatures, the escape of heat from the outer peripheral part has become more remarkable, and more effective measures for soaking are required. Has been.
For example, in the method of making the outer peripheral heating element wiring intervals close, there is a problem in that a short circuit between the wirings easily occurs, the production yield is lowered, and the reliability of the product is lowered. Further, when the resistance value is increased by reducing the wiring width, abnormal heat generation or disconnection may occur. In addition, in the heating method in which the power supply to the heating element is two circuits, the installation position of the power input terminal portion is two places, which complicates the apparatus, and requires two power supplies, thereby enlarging the apparatus. It goes against the trend of space saving, and it is very difficult to improve the temperature distribution by changing only the wiring. Further, although it is possible to optimize the wiring pattern by calculation simulation, it is necessary to accurately reproduce the wiring pattern on an actual heater, which makes the design difficult.
[0008]
As described above, the conventional planar ceramic heater is insufficient in terms of in-plane temperature uniformity for use in processing a large-diameter silicon wafer.
[0009]
[Patent Document 1]
JP-A-8-45651 [Patent Document 2]
JP-A-5-174949
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the conventional planar ceramic heater, and has as its object to provide a planar ceramic heater having excellent in-plane temperature uniformity.
[0011]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a planar ceramic heater including a heating element circuit wiring formed on a ceramic substrate, and a heating object mounting side surface ceramic layer disposed on the surface thereof.
The planar ceramic heater is characterized in that the object-mounting-side surface ceramic layer is composed of two ceramic layers and a soaking layer sandwiched therebetween.
[0012]
In the first aspect of the present invention, it is preferable that the surface ceramic layer on the side on which the object to be heated is made of aluminum nitride because heat from the heat generating element can be transmitted without loss.
[0013]
According to a second aspect of the present invention, there is provided a method for manufacturing a planar ceramic heater including a heating element circuit wiring formed on a ceramic substrate and a heating object mounting side surface ceramic layer disposed on the surface thereof.
A step of forming a heating element circuit on a sintered plate-shaped body serving as a ceramic substrate,
Forming a sintered plate-shaped body to be a ceramic intermediate layer on the heating element circuit;
Forming a soaking layer on the ceramic intermediate layer;
A method for producing a planar ceramic heater, comprising: a step of forming a sintered plate-like body serving as a ceramic surface layer on the heat-equalizing material layer; and heating and pressing the laminate thus obtained.
[0014]
In the second aspect of the present invention, the step of forming the soaking material layer may be a step of forming the soaking material layer by paste printing. According to this method, the possibility of delamination of the constituent layers of the planar ceramic heater can be reduced.
[0015]
Further, in the second aspect of the present invention, the step of forming the heat uniform material layer may be a step of mounting a foil, a plate, or a mesh of the heat uniform material. According to this method, the soaking layer can be efficiently formed, and workability is improved.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
[Structure of planar ceramic heater]
According to the planar ceramic heater of the present invention, in a heater in which a heating element circuit is formed between a ceramic substrate and a heating element surface ceramic layer, a heat equalizing layer for improving uniformity is sandwiched between heating element surface ceramic layers. It was made. The shape of the planar ceramic heater of the present invention will be described with reference to FIG. 1 which is a schematic sectional view of the planar ceramic heater of the present invention. In FIG. 1, reference numeral 1 denotes a planar ceramic heater. The heater 1 includes a ceramic substrate 2 serving as a power supply terminal side surface, a heating element circuit 3 formed on the ceramic substrate 2, A ceramic intermediate layer 4 formed in contact with the heating element circuit 3, a heat equalizing layer 5 formed in contact with the surface of the ceramic intermediate layer 4, and a heat equalizing layer 5 formed in contact with the surface of the heat equalizing layer 5. And at least a ceramic surface layer 6 serving as a surface on which the object to be heated is placed. The power supply terminal 7 can be led out through a hole formed in the ceramic substrate 2 on the power supply terminal side surface of the planar ceramic heater 1.
When the planar ceramic heater 1 is used for heating a silicon wafer, the planar ceramic heater 1 is preferably disk-shaped, but is not limited thereto, and may be a polygon such as a rectangle or an ellipse. good.
In order to reduce the possibility of breakage due to thermal stress, the material constituting the planar ceramic heater of the present invention preferably has substantially the same coefficient of thermal expansion as the material constituting the planar ceramic heater. . Hereinafter, each constituent layer used in the present invention will be described in detail.
[0017]
(Ceramic surface layer)
As a material of the ceramic surface layer 6, a material having heat resistance, being inert under a low temperature atmosphere, and having good thermal conductivity can be used. Specific examples include materials such as aluminum nitride and alumina, but aluminum nitride is most preferable because of its excellent thermal shock resistance and thermal conductivity.
[0018]
(Soaking layer)
This heat equalizing layer 5 is for improving the in-plane temperature non-uniformity of the planar ceramic heating element 1 of the present invention, and a material having high thermal conductivity is preferable. Further, a substrate having a thermal expansion coefficient close to that of AlN of the substrate is preferable. As such a material, W is preferably formed in a layer by paste printing, or a layer formed by means such as sputtering, thermal spraying or the like in addition to wire, foil, plate, mesh.
When the soaking layer is formed by paste printing, the particle size of the soaking layer material powder is preferably in the range of 0.1 to 50 μm. When the particle size range falls below this range, it becomes difficult to form a thick film soaking layer. On the other hand, when the particle size range exceeds this range, it becomes difficult to obtain a smooth surface soaking layer. When the soaking layer material is used as a paste, the coefficient of thermal expansion can be adjusted by adding aluminum nitride powder or the like to the soaking layer material powder. In this case, the mixing ratio between the soaking layer material and the added material is preferably in the range of 100: 0 to 50. If the ratio of the added material exceeds this range, the effect of improving the heat uniformity cannot be expected, which is not preferable.
[0019]
The thickness of the soaking layer 5 is preferably in the range of 5 to 200 μm, more preferably 30 to 100 μm. If the thickness is less than 5 μm, a soaking effect cannot be expected, while if the thickness exceeds 200 μm, it becomes difficult to perform paste printing. Further, when the soaking layer is formed by a method other than the paste printing, the effect of improving the soaking property cannot be obtained, although the amount of the soaking layer material increases, which is uneconomical.
The heat equalizing layer 5 may be formed so as to cover the entire surface of the ceramic intermediate layer 4, or may be formed only at the center of the ceramic intermediate layer 4. When the outer peripheral portion of the ceramic central layer 4 is in contact with the ceramic surface layer 6, the possibility of delamination is reduced when a different material is used as the material of the heat equalizing layer 5.
The heat equalizing layer 5 is sandwiched between the ceramic surface layer 6 and a ceramic intermediate layer 4 described later. The thickness ratio of the ceramic surface layer 6 to the ceramic intermediate layer is in the range of 1: 3 to 3: 1. It is arranged at the position where
[0020]
(Ceramic intermediate layer)
The ceramic intermediate layer 4 is interposed between the soaking layer 5 and the heating element circuit 3 and the ceramic substrate 2 to join them together, and the heat generated in the heating element circuit 3 is efficiently transferred to the soaking layer 5. Materials having the function of transmitting are preferred. As such a material, a material having good thermal conductivity and excellent heat resistance is preferable. Specific examples include aluminum nitride and alumina, but aluminum nitride is preferred because the coefficient of thermal expansion is equal to that of the ceramic surface layer.
[0021]
(Heating element circuit)
The heating element circuit 3 disposed on the ceramic substrate 2 is a circuit wiring formed by using a high-resistance material. Examples of the high-resistance material include metals such as W, Mo, Pt, and Ag, and the like. Alloy can be used. Among them, W having a thermal expansion coefficient close to that of the ceramic surface layer 6 is most suitable. As a method of forming these materials as a heating element circuit, a method of forming a heating element circuit into two ceramic substrates by printing paste of a heating element material powder and a method of forming a heating element circuit pattern by routing wires are provided. , A method of attaching a foil, a plate, a mesh, or the like to the ceramic substrate 2 to form a heating element, or attaching a plate-shaped or foil-shaped material of the above-described material to the ceramic substrate 2 and then forming a heating element circuit pattern. There are various methods such as an etching method, and the method is not limited.
The thickness of the heating element circuit 3 determines the amount of heat generated by the planar ceramic heater 1, and is determined so that the heating element material has a set resistance value.
[0022]
(Ceramic substrate)
As the ceramic substrate 2, any ceramic having good heat resistance can be used. Specifically, aluminum nitride, silicon carbide, silicon nitride, alumina, and the like can be given. Since the ceramic substrate 2 does not come into contact with the object to be heated, it is necessary to dissipate the heat generated from the heating element circuit 3 from the surface as much as possible in order to realize an energy-saving heating device. For that purpose, a material having a low thermal conductivity is preferable. Further, this ceramic heater is used in a temperature range exceeding 800 ° C., and has the same thermal expansion coefficient as that of the ceramic intermediate layer and the like so that the ceramic heater 1 having a laminated structure is not broken by thermal expansion. It is necessary.
The ceramic substrate 2 has terminals 7 for supplying power to the heating element circuit 3. For this purpose, at least two through holes are formed in the ceramic substrate 2.
[0023]
[First Embodiment of Manufacturing Method]
The manufacturing method according to the present embodiment uses, for example, an AlN sintered body processed into a plate shape as a ceramic substrate, a ceramic intermediate layer, and a ceramic surface layer, and uses a ceramic substrate 2, a heating element wiring 3, a ceramic intermediate layer 4, The heat equalizing layer 4 and the ceramic surface layer 6 are laminated by applying a bonding agent between the respective layers, and bonded. Thereafter, a terminal 7 for supplying electricity from the outside is buried so as to be connected to the wiring of the heating element circuit 3 from a through-hole previously opened in the ceramic substrate 2 which is a sintered body, and then a bonding heat treatment is performed. I do. This bonding heat treatment can be performed by a so-called HP process.
[0024]
Next, the joined body is cut to obtain an AlN planar ceramic heater having a shape and dimensions within a predetermined range. The processing of the AlN sintered body may be an ordinary ceramic processing method such as machining or sandblasting. Further, it can be processed and sintered at the time of molding to produce a planar ceramic heater having a predetermined shape and size.
[0025]
Bonding agent used in the method typically can be used and to be used for bonding the sintered ceramic substrate, specifically, AlN-Y ₂ 0 ₃ based materials. In this case, the bonding of the planar ceramic heater laminates can be performed by applying a load of 6 g / cm ² or more at 1550 to 1800 ° C. and performing an HP bonding heat treatment in an inert or reduced pressure atmosphere. This bonding agent may be formed into a paste and screen-printed, or may be dispersed in an organic solvent such as alcohol and applied by spraying onto a base material.
[0026]
In this method, when, for example, a foil of W is used as the material of the heat equalizing layer 5, the bonding strength between the ceramic surface layer or the ceramic intermediate layer and the W foil is low even with the bonding agent, and the foil is easily peeled off. For this reason, it is preferable to form holes as “joining margins” at a plurality of locations of the W foil so that the ceramic surface layer and the ceramic intermediate layer can be directly joined through the holes. The larger the total area of the holes, the higher the bonding strength, but the lower the in-plane temperature uniformity.
[0027]
[Second Embodiment of Manufacturing Method]
The manufacturing method of the second planar ceramic heater is to improve the temperature uniformity of the planar ceramic heater, in particular, as compared with the first embodiment of the manufacturing method. The present invention is characterized in that it does not require the "joining margin" adopted in the above-mentioned embodiment, and has a heat equalizing mechanism capable of closely bonding the ceramic surface layer and the ceramic intermediate layer to the heat equalizing layer.
[0028]
Specifically, a mixed paste of AlN and W, which is a soaking layer component, is formed by baking without adhering to the upper surface of the laminated body including the ceramic base 2, the heating element circuit 3, and the ceramic intermediate layer 4, It is possible to form the soaking layer 5 which is in close contact with the laminated body including the heating element layer. This is a method of manufacturing an AlN ceramic heater characterized by improving the temperature, and can be applied to a thin-wall heater, so that it is possible to provide a heater capable of exhibiting both temperature response and in-plane temperature uniformity.
[0029]
That is, in the first embodiment of the manufacturing method, a metal foil, a mesh, or a sprayed film is embedded as a soaking layer 5 on the surface of the ceramic intermediate layer 4 in order to make the in-plane temperature distribution uniform. According to this method, the heat equalizing layer 5 can be formed by a simple method. However, it is difficult to sufficiently adhere the heat equalizing layer 5 to the ceramic intermediate layer 4, and the heat equalizing layer 5 is formed by repeating heating. May be separated from the ceramic intermediate layer 4. Also, there is a method of providing a large number of through holes for joining to increase the bonding area between the upper and lower substrates in the heat equalizing layer 5 in order to prevent peeling. The temperature distribution in the margin becomes worse. There is also a method of increasing the number of heat equalizing layers in order to alleviate a decrease in the temperature distribution at the joining margin, but there is a problem that the heater structure becomes complicated and the thickness increases.
[0030]
In the manufacturing method of the present embodiment, the AlN sintered body is processed into a shape as shown in FIG. 1 and used as the ceramic substrate 2, the ceramic intermediate layer 4, and the ceramic surface layer 6. The wiring of the heating element circuit 3 is interposed therebetween and bonded, and then the soaking layer 4 is formed on the surface of the ceramic intermediate layer 4 by paste printing, and then the ceramic surface layer 6 is disposed on the surface. Thereafter, a terminal for supplying electricity from the outside is buried so as to be connected to the wiring of the heating element circuit 3 from a hole previously formed in the ceramic substrate 2, and the base materials are joined by joining heat treatment. By processing this joined body, an AlN planar ceramic heater 1 having a soaking layer is obtained. The processing of the AlN sintered body may be an ordinary ceramic processing method such as machining or sandblasting. Further, a substrate may be obtained by processing and sintering at the time of molding.
[0031]
As the paste for forming the soaking layer by the paste printing method, a W-AlN paste is preferable, and the compounding ratio (weight) is suitably in the range of W: AlN = 100: 1 to 30. In this paste, if the amount of AlN added is less than this ratio, the adhesion to the substrate decreases, and if the amount of AlN increases, the thermal conductivity of the soaking layer decreases, and the soaking effect decreases. As a method for producing the paste, a known method can be generally employed in a paste printing method using a ceramic material.
[0032]
Bonding agent used in this method, the material can be used which is used for bonding the usual sintered substrate, specifically, AlN-Y ₂ 0 ₃ based bonding agent. When this bonding agent is used, the planar ceramic heater laminate can be bonded by applying a load of 6 g / cm ² or more at 1550 to 1800 ° C. and performing an HP bonding heat treatment in an inert or reduced pressure atmosphere. This bonding agent may be formed into a paste and screen-printed, or may be dispersed in an organic solvent such as alcohol and applied by spraying onto a base material.
[0033]
【Example】
(Example 1)
Two through-holes were formed in a plate made of an AlN sintered body of φ300 × 4t to obtain a ceramic substrate. By placing a W wire as the heating element circuit 3 on the surface, after coating and drying the AlN-Y ₂ 0 ₃ based bonding agent on the surface thereof, by placing the AlN sintered plate like body having a thickness of 3mm with the same diameter The ceramic intermediate layer 4 was obtained. Then, by printing a W paste on the surface thereof to form a heat equalizing layer 4 of φ295 × 30μm, after drying the paste, and applying and drying the _AlN-Y 2 _{0 3} based bonding agent, a thickness at φ300 to the surface An AlN sintered plate having a thickness of 3 mm was placed thereon to form a ceramic surface layer.
Terminals made of W rods are inserted into the two through holes formed in the ceramic substrate 2, and the laminate is pressure-sintered by HP at a maximum pressure of 0.1 tom / cm ² and a temperature of 1750 ° C. Then, a planar ceramic heater of φ300 × 10 t shown in FIG. 1 was produced.
Electric current was supplied to the planar ceramic heater to perform a heating test. When a heating test was performed at a setting of heating to 800 ° C., the in-plane temperature uniformity of 800 ° C. ± 2 ° C. was shown on the surface of the wafer mounting portion (ceramic surface layer 6).
[0034]
(Example 2)
A heater of φ300 × 10 t was prepared and a heating test was performed in the same manner as in Example 1 except that the soaking layer 4 was formed of W foil of φ295 × 150 μm. When a heating test was performed at a setting of heating to 800 ° C., the in-plane temperature uniformity of 800 ° C. ± 2 ° C. was shown on the wafer mounting portion surface (ceramic surface layer 6).
[0035]
(Example 3)
Except that the soaking layer 4 was formed of a W-AlN (blending ratio: 100: 1) paste of φ295 × 30 μm, a heater of φ300 × 10 t was prepared and a heating test was performed in the same manner as in Example 1. When a heating test was performed at a setting of heating to 800 ° C., in-plane temperature uniformity of 800 ° C. ± 2 ° C. was shown on the surface of the wafer mounting portion (ceramic surface layer 6).
[0036]
(Example 4)
A heater having a diameter of 300 x 10 t was prepared and a heating test was performed in the same manner as in Example 1 except that the soaking layer 4 was formed of a W-AlN (mixing ratio 100: 30) paste having a diameter of 295 x 30 m. When a heating test was performed at a setting of heating to 800 ° C., in-plane temperature uniformity of 800 ° C. ± 2 ° C. was shown on the surface of the wafer mounting portion (ceramic surface layer 6).
[0037]
(Example 5)
Except that the soaking layer 4 was formed of a W-AlN (blending ratio: 100: 1) paste of φ295 × 30 μm, a heater of φ300 × 10 t was prepared and subjected to repeated heating tests in the same manner as in Example 1. When the temperature between room temperature and 800 ° C. was repeated 100 times under the conditions of a temperature rising / falling rate of 300 ° C./hr, there was no peeling of the soaking plate, and a uniform in-plane temperature of 800 ° C. ± 2 ° C. on the surface of the wafer mounting portion (ceramic surface layer 6). Showed sex.
[0038]
(Example 6)
Except that the soaking layer 4 was formed of a W-AlN (blending ratio: 100: 1) paste of φ295 × 30 μm, a heater of φ300 × 10 t was prepared and repeatedly subjected to a heating test in the same manner as in Example 1. When the temperature between room temperature and 800 ° C. was repeated 100 times at a temperature rise / fall rate of 300 ° C./hr, there was no peeling of the soaking plate, and an in-plane temperature of 800 ° C. ± 2 ° C. on the wafer mounting portion surface (ceramic surface layer 6). Showed uniformity.
[0039]
(Example 7)
Except that the soaking layer 4 was formed of W-AlN (blending ratio: 100: 1) paste of φ295 × 30 μm, a thin-walled heater of φ300 × 5 t was prepared and subjected to repeated heating tests in the same manner as in Example 1. . When the temperature between room temperature and 800 ° C. was repeated 100 times at a temperature rise / fall rate of 300 ° C./hr, there was no peeling of the soaking plate, and an in-plane temperature of 800 ° C. ± 2 ° C. on the wafer mounting portion surface (ceramic surface layer 6). Showed uniformity.
[0040]
(Comparative Example 1)
A heater of φ300 × 10 t in which the soaking layer 4 was formed of a W foil of φ295 × 150 μm was prepared and subjected to repeated heating tests. When the temperature between room temperature and 800 ° C. was repeated 30 times under the conditions of a heating / cooling rate of 300 / hr, the soaking layer was separated from the ceramic intermediate layer.
[0041]
(Comparative Example 2)
In order to prevent the heat equalizing layer from peeling off, a heater having a diameter of 300 x 1t was formed by a W foil of φ 295 x 150 µm provided with 37 equally spaced φ 10 like the heat equalizing layer 5a and subjected to repeated heating tests. When the temperature between room temperature and 800 ° C. was repeated 100 times under the conditions of a temperature rise / fall rate of 300 ° C./hr, there was no peeling of the heat equalizing plate, and an in-plane temperature of 800 ° C. ± 40 ° C. on the wafer mounting surface (ceramic surface layer 6). Showed uniformity.
[0042]
(Comparative Example 3)
In order to prevent peeling of the heat equalizing layer, two heat equalizing layer plate-like bodies 5a of W 295 × 150 μm W foil provided with 37 bonding margins φ10 uniformly at 37 places are prepared. A heater having a thickness of φ300 × 20 t was manufactured using the heat equalizing layer 5b formed by rotating one of them by 11.25 ° and laminating the other, and a heating test was repeatedly performed. When the temperature between room temperature and 800 ° C. was repeated 100 times under the conditions of a temperature rise / fall rate of 100 ° C./hr, there was no peeling of the soaking plate, and an in-plane temperature of 800 ° C. ± 3 ° C. on the wafer mounting surface (ceramic surface layer 6). Showed uniformity.
[0043]
【The invention's effect】
According to the present invention, the in-plane temperature uniformity of the planar ceramic heater can be improved by a simple method.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of a planar ceramic heater of the present invention.
FIG. 2 is a front view showing the shape of a soaking layer used in a comparative example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Planar ceramic heater 2 ... Ceramic substrate 3 ... Heating element circuit 4 ... Ceramic intermediate layer 5 ... Thermal uniform layer 6 ... Ceramic surface layer 7 ... Terminal

Claims (5)

In a planar ceramic heater comprising a heating element circuit wiring formed on a ceramic substrate and a surface-mounted ceramic layer on a surface to be heated disposed on the surface thereof,
A planar ceramic heater, wherein the surface ceramic layer on the heated object mounting side is composed of two ceramic layers and a soaking layer sandwiched between the two ceramic layers. 2. The planar ceramic heater according to claim 1, wherein the surface ceramic layer on the placement side of the object to be heated is made of aluminum nitride. In a method for manufacturing a planar ceramic heater comprising a heating element circuit wiring formed on a ceramic substrate and a heating object mounting side surface ceramic layer disposed on the surface thereof,
A step of forming a heating element circuit on a sintered plate-shaped body serving as a ceramic substrate,
Forming a sintered plate-shaped body to be a ceramic intermediate layer on the heating element circuit;
Forming a soaking layer on the ceramic intermediate layer;
A method for manufacturing a planar ceramic heater, comprising: a step of forming a sintered plate-like body serving as a ceramic surface layer on the heat-equalizing material layer; and heating and pressing the laminate thus obtained. 4. The method for manufacturing a planar ceramic heater according to claim 3, wherein the step of forming the soaking material layer is a step of forming the soaking material layer by paste printing. 4. The method for manufacturing a planar ceramic heater according to claim 3, wherein the step of forming the heat uniform material layer is a step of mounting a foil, a plate, or a mesh of the heat uniform material.

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