JP2005279953A - Ceramic structure and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the peeling of a substrate caused by thermal stress and the damage of a ceramic thick film or the substrate in a ceramic structure formed by an AD (aerosol deposition) method. <P>SOLUTION: The ceramic structure includes the substrate 10, an intermediate layer 11 having a first porosity formed by ejecting a ceramic powder to the substrate to deposit the same and a thick film layer 12 formed by ejecting the ceramic powder toward the intermediate layer 11 to deposit the same and having a second porosity lower than the first porosity. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a ceramic structure using a film forming technique in which raw material powder is sprayed and deposited on a substrate.

  In recent years, in the field of micro electrical mechanical systems (MEMS), in order to further integrate sensors and actuators using piezoelectric ceramics for practical use, it is possible to fabricate these elements by film formation. It is being considered. As one of them, an aerosol deposition (AD) method known as a thick film forming technique has attracted attention. Here, the aerosol refers to solid or liquid fine particles suspended in a gas.

  The AD method is a film forming method in which an aerosol containing raw material powder is generated, and the raw material powder is deposited by spraying it from a nozzle toward a substrate. Both the jet deposition method and the gas deposition method are used. being called. In the AD method, the raw material powder sprayed at a high speed collides with the lower layer such as the substrate or the previously formed deposit, and the crushing surface generated by crushing the powder at the time of the collision. Is formed by a mechanochemical reaction that adheres to the lower layer. Therefore, by using the AD method, a dense and strong thick film that does not contain impurities can be formed. Such an AD method is suitable for producing a brittle material (hard brittle material) containing ceramics. The phenomenon in which the raw material powder bites into the lower layer is called anchoring. A film in which PZT, which is one kind of ceramics, is formed on a substrate by the AD method is applied as a piezoelectric actuator, a piezoelectric pump, an inkjet printer head, and an ultrasonic transducer.

  However, since a film made of ceramics or the like (hereinafter also referred to as an AD film) formed by the AD method is in close contact with the substrate, the following problems occur. First, due to the difference in thermal expansion coefficient between the AD film and the substrate, the substrate is deformed in the cooling process or post-annealing process after film formation, and a part of the substrate is peeled off from the AD film or the AD film or the substrate is damaged. Resulting in. In order to prevent this, the substrate material must be selected in accordance with the thermal expansion coefficient of the AD film, which reduces the degree of freedom in selecting the substrate, which increases the manufacturing cost. Second, since it is difficult to peel the substrate from the AD film, the formed AD film can be used only as a composite structure in which the AD film and the substrate are integrated. If an attempt is made to peel off the substrate by chemical etching or the like, the film stress concentrated at the interface between the AD film and the substrate is released, and the reaction causes cracks on the back surface of the AD film, resulting in a decrease in yield. Therefore, the range in which the formed AD film can be applied is narrow.

  By the way, Patent Document 1 discloses a method of manufacturing a phosphor layer using a jet deposition method in order to manufacture a radiation detection apparatus including a phosphor layer having a porosity of 5% to 40%. However, this manufacturing method aims to improve the luminance of the fluorescent layer.

Japanese Patent Laying-Open No. 2003-215256 (first page, FIG. 1)

  Accordingly, in view of the above points, the first object of the present invention is to prevent a substrate from being peeled off due to thermal stress or a ceramic thick film or a substrate from being damaged in a ceramic structure formed by an AD method. To do. A second object of the present invention is to remove a substrate from a ceramic structure formed on the substrate by an AD method without generating cracks or the like.

  In order to solve the above problems, a ceramic structure according to the present invention includes a ceramic layer having a first porosity formed by spraying ceramic powder onto a substrate and depositing the ceramic powder, and the ceramic powder is made of ceramic. And a ceramic thick film layer having a second porosity lower than the first porosity, which is formed by spraying and depositing on the layer.

  The method for producing a ceramic structure according to the present invention includes the step (a) of generating an aerosol containing ceramic powder having a first average particle diameter and spraying the aerosol on a substrate to form a ceramic layer. Forming a ceramic thick film layer by generating an aerosol containing ceramic powder having a second average particle size different from the first average particle size and spraying the aerosol on the ceramic layer (b) It comprises.

  According to the present invention, by providing a ceramic layer having a higher porosity than the ceramic thick film layer between the ceramic thick film layer and the substrate, the stress between them can be relieved. Therefore, the manufacturing yield is improved, and the range of selection of the substrate material can be expanded without being restricted by the difference in the thermal expansion coefficient between the ceramic thick film layer and the substrate, so that the manufacturing cost can be reduced. Become. Further, according to the present invention, by providing a ceramic layer having a higher porosity than the ceramic thick film layer between the ceramic thick film layer and the substrate, the ceramic thick film layer can be separated from the substrate without generating cracks. Can be easily peeled off. Accordingly, a dense and strong ceramic structure formed by the AD method can be used alone, and the degree of freedom in designing the product is increased.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. The same constituent elements are denoted by the same reference numerals, and the description thereof is omitted. In the present application, the thick film refers to a film having a thickness of about 100 μm to several hundred μm.
FIG. 1 is a cross-sectional view showing a configuration of a ceramic structure according to the first embodiment of the present invention. This ceramic structure includes a substrate 10, an intermediate layer 11, and a thick film layer 12.

  The substrate 10 is a base material used from the formation of the intermediate layer 11 and the thick film layer 12 to subsequent manufacturing processes or products. In the present embodiment, SUS (steel for special use) is used as the substrate 10, but various materials such as glass and ceramics can also be used.

  The intermediate layer 11 and the thick film layer 12 are both ceramic layers having the same composition. In each layer, the porosity and the average crystal grain size are different from each other, and as a result, the hardness is also different from each other. Here, the porosity is a ratio of a void portion existing inside a structure such as ceramics, and is represented by porosity (%) = 100% −filling rate (%). The filling rate is the ratio of the volume actually occupied by the particles contained in the structure to the volume of the entire structure such as ceramics.

  The thick film layer 12 is, for example, a PZT (lead zirconate titanate) thick film having a thickness of about 100 μm. Moreover, the porosity of the thick film layer 12 is 5% or less, for example. The PZT thick film is used, for example, in piezoelectric actuators, piezoelectric pumps, ink jet printer ink heads, ultrasonic transducers, and the like by disposing electrodes at both ends thereof.

  On the other hand, the intermediate layer 11 is a PZT thin film having a thickness of about 10 μm, for example. The porosity of the intermediate layer 11 is higher than the porosity of the thick film layer 12, and is, for example, 10% to 20%. Accordingly, the hardness of the intermediate layer 11 is smaller than that of the thick film layer 12.

  By providing such an intermediate layer 11 between the thick film layer 12 and the substrate 10, even if a large temperature change occurs in the ceramic structure shown in FIG. Absorbed. Therefore, also in the process after the formation of the thick film layer 12 (for example, a cooling process after film formation or a post-annealing process), the substrate 10 is prevented from being peeled from the thick film layer 12 or any of them is damaged. Therefore, the material of the substrate 10 can be selected without being constrained by the difference in thermal expansion coefficient between the substrate 10 and the thick film layer 12. Further, since the intermediate layer 11 and the thick film layer 12 have the same composition, there is no need to worry about reactions such as diffusion at the interface.

  Next, a method for manufacturing a ceramic structure according to this embodiment will be described. In this embodiment, the intermediate layer 11 and the thick film layer 12 are formed by an aerosol deposition (AD) method in which an aerosol containing raw material powder is deposited by spraying on a substrate.

FIG. 2 is a schematic diagram showing a film forming apparatus using the AD method. This film forming apparatus includes a gas cylinder 1, transfer pipes 2 a and 2 b, an aerosol generation chamber 3, a film forming chamber 4, an exhaust pump 5, a nozzle 6, and a substrate holder 7.
The gas cylinder 1 is filled with nitrogen (N ₂ ), oxygen (O ₂ ), helium (He), argon (Ar), dry air or the like used as a carrier gas. The gas cylinder 1 is provided with a pressure adjusting unit 1a for adjusting the supply amount of the carrier gas. The aerosol generation chamber 3 is a container in which a fine powder of a raw material that is a film forming material is placed. By introducing a carrier gas from the gas cylinder 1 into the aerosol generation chamber 3 through the transport pipe 2a, the raw material powder disposed there is blown up to generate the aerosol 101. The generated aerosol 101 is supplied to the nozzle 6 through the transport pipe 2b.

  The inside of the film forming chamber 4 is evacuated by an exhaust pump 5 and thereby maintained at a predetermined degree of vacuum. Further, a nozzle 6 for injecting the aerosol 101 and a substrate holder 7 for holding the substrate 10 on which the structure is formed are arranged in the film forming chamber 4. The substrate holder 7 is provided with a substrate holder driving unit 7a for moving the substrate holder 7 in a three-dimensional manner, whereby the relative position and relative speed between the nozzle 6 and the substrate 10 are controlled.

  When the ceramic structure shown in FIG. 1 is manufactured, first, the substrate 10 is placed in the film forming chamber 4 and the substrate 10 is kept at a predetermined film forming temperature (for example, 600 ° C.). Next, PZT powder as a raw material for the intermediate layer 11 is arranged in the aerosol generation chamber 3 to generate the aerosol 101 and supply it to the nozzle. As a result, the PZT powder ejected from the nozzle at high speed collides with the substrate and accumulates, and the intermediate layer 11 is formed. Next, the PZT powder used as the raw material of the thick film layer 12 is arrange | positioned in the aerosol production | generation chamber 3, and the thick film layer 12 is formed by performing film-forming similarly.

Next, a method and principle for changing the porosity of the intermediate layer 11 and the thick film layer 12 having the same composition will be described in detail.
In the AD method, it is known that there are differences in film quality, deposition rate, and the like of the formed film due to various conditions regarding the powder sprayed from the nozzle. For example, the raw material powder (primary particles) placed in the aerosol generating container aggregates over time to form secondary aggregated particles due to electrostatic force, van der Waals force, or moisture cross-linking effect. Resulting in. Even if such secondary agglomerated particles collide with the substrate, the kinetic energy possessed by the secondary agglomerated particles is used for crushing itself, so it does not form a crushing surface, and therefore adheres to the lower layer. do not do. For this reason, the secondary agglomerated particles cannot contribute to the film formation, and in some cases, the previously formed deposit is blasted. Moreover, even if the powder to be sprayed is primary particles, it is empirically known that there exists an average particle diameter range suitable for film formation.

  Therefore, the inventor of the present application paid attention to the average particle diameter of the raw material powder and examined the relationship between the average particle diameter and the quality of the AD film. That is, the present inventor forms an AD film using the film forming apparatus shown in FIG. 2 while changing the average particle diameter of the PZT powder in the range of 0.2 μm to 0.3 μm. The surface was observed and the hardness was measured. As a result, it was found that there is a certain relationship between the average particle diameter of the raw material powder and the film quality of the AD film.

  First, when the surface of the formed AD film was observed using an SEM (scanning electron microscope), the average crystal grain in the AD film was larger as the average particle diameter of the raw material PZT powder was larger (for example, 0.3 μm). The diameter was small and the porosity was low (for example, 5% or less). Conversely, the smaller the average particle size of the raw material PZT powder (for example, 0.2 μm), the larger the average crystal particle size in the AD film and the higher the porosity (for example, 10% or more).

  FIG. 3 shows the relationship between the average particle diameter (μm) of the raw material PZT powder and the Vickers hardness (Hv) of the AD film. As shown in FIG. 3, the larger the average particle diameter of the raw material PZT powder, the larger the Vickers hardness of the formed AD film, and the smaller the average particle diameter of the raw material PZT powder, Vickers hardness is small. For comparison, FIG. 3 shows the Vickers hardness of a general PZT bulk material.

These observation results and measurement results are considered to be caused by the following mechanism. That is, the primary particles having a large particle diameter have a large kinetic energy when ejected from the nozzle, and thus are easily crushed when they collide with the substrate. For this reason, the fragmented primary particles are bonded to each other by a mechanochemical reaction, so that a dense and strong AD film is formed. On the other hand, primary particles having a small particle diameter have a small kinetic energy, so that even if they collide with a substrate, they are difficult to be crushed. Even when such primary particles collide with the substrate, they are only trapped and deposited in the lower layer, so that the film has a high porosity and becomes a relatively fragile film.
Therefore, by defining the average particle size of the raw material powder based on such a mechanism, it becomes possible to control the average crystal particle size, porosity, and hardness of the AD film.

  Therefore, in this embodiment, when forming the intermediate layer 11 and the thick film layer 12, PZT powders having different average particle diameters are used. That is, when the thick film layer 12 is formed, for example, a PZT powder having an average particle diameter of about 0.3 μm to 0.4 μm is used, and when the intermediate layer 11 is formed, the average particle is larger than that. A PZT powder having a small diameter (for example, about 0.1 μm to 0.2 μm) is used. Thereby, compared with the thick film layer 12, the intermediate | middle layer 11 with a large average crystal grain diameter and porosity, and small hardness can be formed.

  In order to obtain a PZT powder having a desired average particle size, as one method, two or more types of PZT fine powders having different particle size distribution center values may be mixed. For example, the smaller PZT fine powder having a particle size distribution center value of 0.1 μm to 0.5 μm is used, and the larger PZT fine powder having a particle size distribution center value of 0.2 μm to 0.6 μm. Use them and mix them in a certain proportion. More preferably, the smaller PZT fine powder having a particle size distribution center value of 0.1 μm to 0.2 μm is used, and the larger PZT fine powder having a particle size distribution center value of 0.3 μm to 0.2 μm. Those having a thickness of 4 μm are used and mixed at a predetermined ratio.

  Thus, the ceramic structure according to the present embodiment is manufactured, but such a ceramic structure may be annealed at a predetermined temperature. Thereby, the grain size of the PZT crystal contained in the thick film layer 12 can be increased and the piezoelectric performance can be improved. By annealing, the average crystal grain size of the intermediate layer 11 and the thick film layer 12 changes from the average crystal grain size immediately after the film formation, but in any layer, it becomes 500 nm or less.

  In the first embodiment of the present invention described above, the aerosol is generated using the raw material powder whose average particle diameter is adjusted in advance. However, an aerosol containing powder having a desired average particle diameter may be generated by mixing a plurality of types of aerosols. For that purpose, the film forming apparatus shown in FIG. 4 may be used. This film forming apparatus further includes a gas cylinder 8 and a carrier gas generation chamber 9 in addition to the film forming apparatus shown in FIG. Other configurations are the same as those of the film forming apparatus shown in FIG.

  As shown in FIG. 4, aerosols 101 and 102 are generated in the aerosol generation chambers 3 and 9, respectively. These aerosols 101 and 102 are mixed during conveyance in the conveyance pipe 2b. At that time, the mixing ratio of the aerosol 101 and the aerosol 102 can be adjusted by controlling the flow rate of the carrier gas supplied from the gas cylinders 1 and 8, respectively. Thereby, the average particle diameter of the raw material powder contained in the aerosol 103 injected from the nozzle 6 can be adjusted.

When the ceramic structure shown in FIG. 1 is manufactured, the smaller PZT fine powder (for example, having a median particle size distribution of 0.1 μm to 0.5 μm) is placed in one aerosol generation chamber 3, In the other aerosol generation chamber 9, the larger PZT fine powder (for example, one having a median value of the particle size distribution of 0.2 μm to 0.6 μm) is arranged. Then, the intermediate layer 11 is formed while adjusting the supply amount of the carrier gas so that the aerosol 101 and the aerosol 102 are supplied at a predetermined ratio. Next, the supply of the aerosol 101 is stopped, and the thick film layer 12 is formed using only the aerosol 102.
By using such a film forming apparatus, it is possible to easily generate an aerosol containing powder having a desired average particle diameter, and each time a different layer is formed, the raw material powder to be disposed in the aerosol generating chamber This eliminates the need for replacement and saves time.

Next, a modified example of the ceramic structure according to the first embodiment of the present invention will be described.
FIG. 5 is a cross-sectional view showing a first modification of the ceramic structure according to the present embodiment. This ceramic structure includes a glass substrate 20, a lower electrode 21, an intermediate layer 22, a thick film layer 23, and an upper electrode 24. The lower electrode 21 is, for example, a 300 nm platinum (Pt) layer. Platinum has low reactivity with PZT, and has an appropriate elasticity that allows the raw material powder to be easily anchored in the AD method. The intermediate layer 22 and the thick film layer 23 are PZT layers having different porosities, like the intermediate layer 11 and the thick film layer 12 shown in FIG. The upper electrode 24 is a two-layer electrode including a titanium oxide (TiO ₂ ) layer 24a of about 20 nm and a platinum layer 24b of about 200 nm. The titanium oxide layer 24a is provided to bring the thick film layer 12 and the platinum layer 24a into close contact with each other.

  As shown in this modification, by forming the lower electrode 21 on the substrate 20 in advance, the manufactured ceramic structure can be directly applied to an application such as a piezoelectric actuator. Even in such a case, by providing the intermediate layer 22, the stress between the substrate 20 and the thick film layer 23 is relieved, so that the performance of the ceramic structure can be improved. In addition, a multilayer capacitor structure may be configured by alternately laminating a plurality of PZT thick films and electrodes on the upper electrode 24.

  Moreover, you may provide the some intermediate | middle layer from which a porosity changes in steps as a 2nd modification of the ceramic structure which concerns on this embodiment. For example, three intermediate layers are formed so that the porosity changes from 20%, 15%, and 10% from the substrate side, and a thick film layer is formed thereon. By setting the porosity of each intermediate layer according to the difference between the thermal contraction coefficient of the substrate and the thermal contraction coefficient of the thick film layer, the thermal stress between the thick film layer can be absorbed more efficiently. Further, it becomes possible to further expand the range of selection of the substrate material.

  Furthermore, you may provide the intermediate | middle layer from which a porosity changes continuously as a 3rd modification of the ceramic structure which concerns on this embodiment. FIG. 6 is a cross-sectional view showing a third modification of the ceramic structure according to the present embodiment. This ceramic structure includes a substrate 30, an intermediate layer 31, and a thick film layer 32.

In the intermediate layer 31, for example, the porosity on the substrate 30 side is about 20%, the porosity on the thick film layer 32 side is about 5%, and the porosity changes continuously in the region in between. Thus, by gradually changing the hardness by inclining the porosity of the intermediate layer, the thermal stress generated between the substrate 30 and the thick film layer 32 can be absorbed more efficiently.
In order to form such an intermediate layer 31, raw material powders having different center values of particle size distribution are arranged in the aerosol generation chambers 3 and 9 of the film forming apparatus shown in FIG. Film formation may be performed while continuously changing the supply ratio of the aerosol 102.

Next, a ceramic structure and a manufacturing method thereof according to the second embodiment of the present invention will be described. FIG. 7 is a cross-sectional view showing a ceramic structure according to the present embodiment.
The ceramic structure shown in FIG. 7 includes a peeling sacrificial layer 41 and a thick film layer 42 having the same composition. The peeling sacrificial layer 41 has a porosity of about 20% to 40%, and the thick film layer 42 has a porosity of about 5%. This ceramic structure can be used as a ceramic material in the same manner as a general bulk material.

FIG. 8 is a diagram for explaining a method for manufacturing a ceramic structure according to the present embodiment.
First, the substrate 40 is placed in the film forming apparatus shown in FIG. 1 or FIG. 4 and kept at a predetermined film forming temperature (for example, 600 ° C.). In the present embodiment, SUS is used as the material of the substrate 40. Next, using a PZT powder whose average particle diameter is adjusted so that the porosity is about 20% to 40%, a peeling sacrificial layer 41 is formed on the substrate 40 by the AD method. Further, as the raw material powder, for example, PZT powder having an average particle diameter of 0.3 μm is used, and the thick film layer 42 is formed on the peeling sacrifice layer 41 by the AD method.

Next, as shown in FIG. 8B, the substrate on which the separation sacrificial layer 41 and the thick film layer 42 are formed is selectively removed by chemical etching. As the etchant 43, for example, a normal temperature ferric chloride solution (FeCl ₃ ) that dissolves the SUS substrate is used. As a result, as shown in FIG. 8C, a ceramic structure from which the substrate 40 has been removed is obtained.
Further, if necessary, the ceramic structure shown in FIG. 7 can be obtained by polishing the lower part of the ceramic structure shown in FIG. Further, before or after that, the ceramic structure may be annealed at a predetermined temperature.

Next, another method for manufacturing the ceramic structure according to this embodiment will be described. In FIG. 8, when removing the substrate 40 from the peeling sacrificial layer 41 and the thick film layer 42, the substrate 40 may be peeled off by heat treatment instead of using an etching solution. That is, the structure after film formation shown in FIG. 8A is heated to a temperature higher than the film formation temperature (for example, about 700 ° C.). As a result, thermal stress is generated at the interface between the substrate 40 and the thick film layer 42, and the substrate 40 is peeled off due to breakage in the peeling sacrifice layer 41 having the smallest hardness. Further, by polishing the fracture surface, the ceramic structure shown in FIG. 7 is obtained.
Thus, according to the present embodiment, the substrate can be easily peeled without causing cracks or the like in the thick film layer.

In the first and second embodiments described above, PZT is used as the ceramic. However, in the present invention, oxide ceramics including alumina (Al ₂ O ₃ ), titanium oxide TiO ₂ , It can be applied to any ceramics including carbide ceramics such as silicon (SiC), nitride ceramics such as silicon nitride (Si ₃ N ₄ ), and non-oxide ceramics including boride ceramics such as titanium boride (TiB ₂ ). it can. When the present invention is applied to ceramics other than PZT, the range of the average particle diameter of the powder that can be used as a raw material for the AD method, the correspondence between the average particle diameter and the porosity or hardness, etc. It is considered different from the case. Therefore, it is desirable to measure the corresponding relationship in advance according to the material to be used.

  The present invention can be used in structures using ceramic materials such as multilayer capacitors and piezoelectric actuators.

1 is a cross-sectional view illustrating a ceramic structure according to a first embodiment of the present invention. It is a schematic diagram which shows the film-forming apparatus by AD method. It is a figure showing the relationship between the average particle diameter of the raw material PZT powder, and the Vickers hardness of AD film. It is a schematic diagram which shows another film-forming apparatus by AD method. It is sectional drawing which shows the 1st modification of the ceramic structure which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the 3rd modification of the ceramic structure which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the ceramic structure which concerns on the 2nd Embodiment of this invention. It is a figure for demonstrating the manufacturing method of the ceramic structure shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 8 Gas cylinder 1a Pressure adjustment part 2a, 2b Conveyance pipe | tube 3, 9 Aerosol production | generation chamber 4 Film-forming chamber 5 Exhaust pump 6 Nozzle 7 Substrate holder 7a Substrate holder drive part 10, 20, 30, 40 Substrate 11, 22, 31, 41 Intermediate layer 12, 23, 32, 42 Thick film layer 21, 24 Electrode 43 Etching solution 101-103 Aerosol

Claims (16)

A ceramic layer having a first porosity formed by spraying ceramic powder onto a substrate and depositing the ceramic powder;
A ceramic thick film layer having a second porosity lower than the first porosity, which is formed by spraying and depositing ceramic powder toward the ceramic layer;
A ceramic structure comprising:   The ceramic structure according to claim 1, wherein the ceramic layer and the ceramic thick film layer have the same composition. The first porosity is 20% or more and 40% or less;
The second porosity is 5% or less,
The ceramic structure according to claim 1 or 2.   The ceramic structure according to claim 1, further comprising a substrate on which the ceramic layer is disposed on the main surface. The first porosity is 10% or more and 20% or less;
The second porosity is 5% or less,
The ceramic structure according to claim 4.   The ceramic structure according to any one of claims 1 to 5, wherein a porosity of the ceramic layer continuously changes in a thickness direction.   The ceramic structure according to claim 1, wherein an average crystal grain size in the ceramic layer is larger than an average crystal grain size in the ceramic thick film layer.   The ceramic structure according to claim 7, wherein an average crystal grain size in the ceramic layer is 500 nm or less.   The ceramic structure according to claim 1, wherein a Vickers hardness of the ceramic layer is smaller than a Vickers hardness of the ceramic thick film layer. Producing an aerosol containing ceramic powder having a first average particle size, and spraying the aerosol on a substrate to form a ceramic layer;
Producing a ceramic powder having a second average particle diameter different from the first average particle diameter, and spraying the aerosol onto the ceramic layer to form a ceramic thick film layer; and
A method for producing a ceramic structure comprising:   The method for producing a ceramic structure according to claim 10, wherein the ceramic powders having the first and second average particle diameters have the same composition.   The method for producing a ceramic structure according to claim 10 or 11, wherein the first average particle diameter is smaller than the second average particle diameter.   Before the step (a) or (b), the first or second average particle size is obtained by mixing a plurality of types of ceramic powders having different center values of particle size distribution at a predetermined ratio. The method for producing a ceramic structure according to any one of claims 10 to 12, further comprising a step of producing a ceramic powder.   The step (a) or (b) includes generating a plurality of types of aerosols including ceramic powders having median values of particle size distributions different from each other, and mixing the plurality of types of aerosols at a predetermined ratio. Item 13. A method for producing a ceramic structure according to any one of Items 10 to 12.   The method for manufacturing a ceramic structure according to any one of claims 10 to 14, further comprising a step of selectively dissolving the substrate by immersing the substrate on which the ceramic thick film layer is formed in a chemical solution. By heat-treating the substrate on which the ceramic layer and the ceramic thick film layer are formed at a temperature higher than the temperature at which the ceramic layer and the ceramic thick film layer are formed, the ceramic thick film layer and the substrate are The method for manufacturing a ceramic structure according to claim 10, further comprising a step of separating the ceramic layer.

Images