WO2021235407A1 - Ceramic place production method, setter production method, and setter regeneration method - Google Patents

Ceramic place production method, setter production method, and setter regeneration method Download PDF

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Publication number
WO2021235407A1
WO2021235407A1 PCT/JP2021/018676 JP2021018676W WO2021235407A1 WO 2021235407 A1 WO2021235407 A1 WO 2021235407A1 JP 2021018676 W JP2021018676 W JP 2021018676W WO 2021235407 A1 WO2021235407 A1 WO 2021235407A1
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Prior art keywords
setter
ceramic green
green sheet
contact surface
ceramic
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PCT/JP2021/018676
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French (fr)
Japanese (ja)
Inventor
利貴 山縣
満博 山口
里樹 東
江 尹
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デンカ株式会社
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Priority to JP2022524473A priority Critical patent/JP7185099B2/en
Publication of WO2021235407A1 publication Critical patent/WO2021235407A1/en

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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • C04B35/58—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides
    • C04B35/584—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on silicon nitride
    • C04B35/587—Fine ceramics
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/64—Burning or sintering processes

Definitions

  • This disclosure relates to a method for manufacturing a ceramic plate, a method for manufacturing a setter, and a method for regenerating a setter.
  • Power modules that control large currents are used in fields such as automobiles, electric railways, industrial equipment, and power generation.
  • the circuit board mounted on the power module has an insulating ceramic plate.
  • a method for manufacturing a ceramic plate for example, the following manufacturing method as described in Patent Document 1 is known. That is, a step of extruding the ceramic powder into a sheet after mixing it with a sintering aid or the like, a step of punching to form a ceramic green sheet, and a step of firing the ceramic green sheet are performed. Then, a ceramic plate is manufactured. In the firing step of the ceramic green sheet, the ceramic green sheet is fired in a state where about 10 to 20 ceramic green sheets are laminated on the setter.
  • the present disclosure provides a method for manufacturing a ceramic plate, which can improve the production efficiency of the ceramic plate by regenerating the setter. Further, the present invention provides a method for manufacturing a setter and a method for regenerating the setter, which can effectively utilize resources.
  • the method for manufacturing a ceramic plate includes a first firing step of laminating and firing the setter and the first ceramic green sheet so as to be in contact with each other to obtain a ceramic plate, and a first ceramic green sheet.
  • the heating step of heating the setter with at least a part of the contact surface of the setter exposed and the second ceramic green sheet are laminated and fired so as to be in contact with each other at at least a part of the contact surface. It has a second firing step of obtaining a ceramic plate.
  • the setter is heated with at least a part of the contact surface of the setter exposed, which was in contact with the first ceramic green sheet.
  • the temperature may be higher than the temperature at which the foreign matter containing a component different from the component contained in the setter that adheres to the contact surface is decomposed.
  • the "component contained in the setter” in the present disclosure refers to a component originally contained in the setter before it is used in the method for manufacturing a ceramic plate. That is, it is a component (constituent component) contained in an unused setter.
  • the component contained in the setter composed of the boron nitride sintered body is boron nitride.
  • a plurality of setters including the above setter and a plurality of first ceramic green sheets including the first ceramic green sheet may be laminated and fired so as to be in contact with each other.
  • the plurality of setters may be heated with the contact surfaces of the plurality of setters in contact with the first ceramic green sheet separated from each other. This allows a plurality of setters to be heated and regenerated together. Therefore, the production efficiency of the ceramic plate can be further improved.
  • the first ceramic green sheet contains silicon nitride
  • the setter may be heated at 1450 to 2000 ° C. in an atmosphere of an inert gas.
  • the decomposition of silicon nitride contained in the foreign matter proceeds smoothly, and the time required for the heating step can be shortened.
  • foreign matter on the contact surface of the setter can be sufficiently reduced, and unevenness generated on the surface of the ceramic plate obtained in the second firing step can be further reduced.
  • the method for manufacturing a setter according to one aspect of the present disclosure is different from the components contained in the first setter on the contact surface with the ceramic green sheet by laminating and firing so that the first setter and the ceramic green sheet are in contact with each other. It has a firing step of obtaining a second setter to which foreign matter containing a component is attached, and a heating step of heating the second setter with at least a part of the contact surface exposed to reduce foreign matter on the contact surface. ..
  • the above-mentioned manufacturing method has a heating step of heating the second setter in which foreign matter adheres to the contact surface with the ceramic green sheet in the firing step.
  • the second setter is heated with at least a part of the contact surface exposed to reduce foreign matter on the contact surface.
  • the setter (third setter) obtained by reducing the amount of foreign matter can be laminated and fired so as to be in contact with the ceramic green sheet again.
  • the waste amount of the setter can be reduced and the resources can be effectively utilized by manufacturing the setter (third setter) in which the foreign matter is reduced from the second setter to which the foreign matter is attached. can.
  • the temperature may be higher than the temperature at which the foreign matter decomposes. As a result, foreign matter adhering to the contact surface can be sufficiently and smoothly reduced. Therefore, the setter can be efficiently manufactured.
  • a plurality of first setters including the first setter and a plurality of ceramic green sheets including the ceramic green sheet are laminated and fired so as to be in contact with each other, and a plurality of second setsters including the second setter are fired. You may get 2 setters.
  • the plurality of second setters may be heated with the contact surfaces of the plurality of second setters in contact with the ceramic green sheet separated from each other. Thereby, a plurality of second setters can be heated together to produce a plurality of setters at the same time. Therefore, the production efficiency of the setter can be improved.
  • the ceramic green sheet contains silicon nitride, and in the heating step, the second setter may be heated at 1450 to 2000 ° C. in an atmosphere of an inert gas.
  • the decomposition of silicon nitride contained in the foreign matter proceeds smoothly, and the time required for the heating step can be shortened.
  • the method for regenerating a setter according to one aspect of the present disclosure is different from the components contained in the first setter on the contact surface with the ceramic green sheet by laminating and firing so that the first setter and the ceramic green sheet are in contact with each other. It has a firing step of obtaining a second setter to which foreign matter containing a component is attached, and a heating step of heating the second setter with at least a part of the contact surface exposed to reduce foreign matter on the contact surface.
  • the above-mentioned regeneration method has a heating step of heating the second setter in which foreign matter adheres to the contact surface with the ceramic green sheet in the firing step.
  • the second setter is heated with at least a part of the contact surface exposed to reduce foreign matter on the contact surface.
  • the setter (third setter) obtained by reducing the amount of foreign matter can be laminated and fired so as to be in contact with the ceramic green sheet again.
  • the waste amount of the setter can be reduced and the resources can be effectively utilized by regenerating the setter (third setter) in which the foreign matter is reduced from the second setter to which the foreign matter is attached. can.
  • the present disclosure it is possible to provide a method for manufacturing a ceramic plate capable of improving the production efficiency of the ceramic plate by regenerating the setter. Further, it is possible to provide a method for manufacturing a setter and a method for regenerating the setter that can effectively utilize resources.
  • FIG. 6 is an SEM photograph showing an example of foreign matter (boron nitride particles) adhering to the contact surface of a setter made of a boron nitride sintered body. It is a figure which shows an example of a heating process. It is an SEM photograph which shows the main surface (before firing) of the setter used in Example 1.
  • FIG. 6 is an SEM photograph showing the main surface of FIG. 4 taken at a higher magnification than that of FIG.
  • FIG. 6 is an SEM photograph which shows the contact surface of the setter after the 1st firing step of Example 1.
  • FIG. 6 is an SEM photograph showing the contact surface of FIG. 6 taken at a higher magnification than that of FIG.
  • FIG. 6 is an SEM photograph showing the contact surface of FIG. 8 taken at a higher magnification than that of FIG. 6 is an SEM photograph showing the contact surface of the setter after the heating step of Comparative Example 1.
  • 11 is an SEM photograph showing the contact surface of FIG. 10 taken at a higher magnification than that of FIG. 11. It is a photograph which shows the example of the convex part on the surface of a silicon nitride plate.
  • a laminated body (first laminated body) laminated so that a setter and a ceramic green sheet (first ceramic green sheet) are in contact with each other is fired to obtain a ceramic plate.
  • the second firing to obtain a ceramic plate by firing the laminated body (second laminated body) in which the setter and the ceramic green sheet (second ceramic green sheet) are laminated so as to be in contact with each other at at least a part of the contact surface. It has a process.
  • the first ceramic green sheet and the second ceramic green sheet are ceramic green sheets laminated so as to be in contact with the setter.
  • the first ceramic green sheet and the second ceramic green sheet laminated so as to be in contact with the setter in the first firing step and the second firing step are manufactured by, for example, the following procedure.
  • First, a raw material slurry containing a ceramic powder, a sintering aid and a binder is formed.
  • the ceramic is not particularly limited, and examples thereof include carbides, oxides, and nitrides. Specific examples thereof include silicon carbide, alumina, silicon nitride, aluminum nitride and boron nitride.
  • Binders include those containing organic components.
  • first ceramic green sheet and a second ceramic green sheet may be processed into a desired shape by, for example, cutting.
  • the materials and shapes of the first ceramic green sheet and the second ceramic green sheet may be the same or different.
  • the setter for example, a commercially available ceramic sintered body may be purchased, or may be manufactured by a known method.
  • the setter include those containing at least one selected from the group consisting of boron nitride, silicon carbide, alumina, zirconia, graphite, and silicon nitride.
  • a setter made of boron nitride is preferably used because it has both heat resistance and good machinability.
  • the material of the setter may be different from the material of the ceramic plate from the viewpoint of suppressing the adhesion between the setter and the ceramic plate after firing.
  • a boron nitride sintered body When a boron nitride sintered body is used as the setter, it can be manufactured by the following procedure. First, a molded product is produced using hexagonal boron nitride powder as a raw material. If necessary, a sintering aid may be added to the hexagonal boron nitride powder before molding. Examples of the sintering aid include alkaline earth oxides such as magnesium oxide and calcium oxide, rare earth oxides such as aluminum oxide, silicon oxide and yttrium oxide, and composite oxides such as spinel.
  • the molding may be performed by uniaxial pressure molding and CIP molding. Uniaxial pressure molding may be performed at 3 to 20 MPa. CIP molding may be performed at 50 to 300 MPa.
  • the obtained molded product is fired to obtain a boron nitride sintered body.
  • the firing may be carried out under the conditions of a non-oxidizing atmosphere, a heating rate of 150 ° C./hr or less, a maximum temperature of 1800 to 2200 ° C., and a holding time of 5 hours or more in this temperature range.
  • the non-oxidizing atmosphere include a nitride gas atmosphere such as nitrogen and ammonia.
  • the density of the boron nitride sintered body may be 1600 kg / m 3 or more.
  • the method for producing the boron nitride sintered body is not limited to the above method. For example, it may be manufactured by a hot press method. Ceramic sintered bodies other than the boron nitride sintered body can be produced by a known method.
  • the setter thus obtained and the first ceramic green sheet are laminated so as to be in contact with each other to produce a laminated body.
  • the number of setters and ceramic green sheets constituting the laminate is not particularly limited.
  • As the laminate for example, a plurality of (for example, 50 to 100) ceramic green sheets including the first ceramic green sheet may be sandwiched between a pair of setters. Further, one setter and a plurality of ceramic green sheets including the first ceramic green sheet may be arranged alternately. As described above, by firing a plurality of ceramic green sheets in the first firing step, a plurality of ceramic plates can be manufactured at the same time.
  • the material and shape of the ceramic green sheet laminated together with the first ceramic green sheet may be the same as or different from that of the first ceramic green sheet.
  • a mold release agent may be applied to the main surface of the ceramic green sheet (first ceramic green sheet) in order to prevent the adjacent ceramic green sheets from adhering to each other during firing. Further, the mold release agent may be applied to the surface of the setter facing the main surface of the first ceramic green sheet. Examples of the component contained in the release agent include ceramic powder such as boron nitride, graphite powder, and binder.
  • FIG. 1 is a diagram illustrating an example of the first firing step of the laminated body.
  • the laminate 50 includes three setters 10 and a plurality of ceramic green sheets 30.
  • the plurality of ceramic green sheets 30 include four first ceramic green sheets 30a adjacent to the three setters 10.
  • the pair of setters 10A and 10B are laminated at the bottom and top of the laminated body 50. Therefore, in the setters 10A and 10B, one main surface is in contact with the first ceramic green sheet 30a.
  • the remaining setter 10C is laminated in the central portion of the laminated body 50. Therefore, both main surfaces of the setter 10C are in contact with the first ceramic green sheet 30a.
  • the contact surface of the setter 10 in which the first ceramic green sheet 30a and the setter 10 come into contact with each other is included in one or both main surfaces.
  • the laminated body 50 is housed in a degreasing furnace 20 and heated to, for example, 300 ° C. to 700 ° C. As a result, the binder contained in the ceramic green sheet 30 is removed. Subsequently, the degreased laminate 50 is housed in the firing furnace 25 and heated to 1600 ° C to 2000 ° C. As a result, the ceramic green sheet is fired and a ceramic plate is obtained.
  • the degreasing furnace 20 used for degreasing and the firing furnace 25 used for firing may be the same furnace or different furnaces. Further, the heating temperature, time and atmosphere may be appropriately adjusted according to the composition of the ceramic green sheet.
  • the laminated body (first laminated body) fired in the first firing step is separated into a ceramic plate and a setter.
  • the obtained ceramic plate may be processed as necessary to form, for example, a circuit board.
  • Granular foreign matter containing a component different from the component contained in the setter adheres to the contact surface that has been in contact with the first ceramic green sheet 30a (ceramic plate) of the separated setter.
  • the components contained in the foreign substance include components contained in a ceramic green sheet or a ceramic plate, and reaction products of these components and components contained in a setter.
  • the particle size of the foreign matter may be larger than the particles constituting the setter. That is, the foreign matter may be coarse particles.
  • FIG. 2 is an SEM photograph showing an example of foreign matter (boron nitride particles) adhering to the contact surface of a setter composed of a boron nitride sintered body.
  • the composition of foreign matter can be measured by EDS analysis.
  • the setter is composed of a boron nitride sintered body and the foreign matter is silicon nitride particles, it is difficult to find the foreign matter with the naked eye because the colors of both are similar.
  • the presence or absence of a foreign substance can be determined by performing SEM observation at a high magnification (for example, 500 times or more) as shown in FIG.
  • the setter with such foreign matter adhering to the contact surface is heated with the contact surface exposed.
  • foreign matter adhering to the contact surface can be volatilized or decomposed and reduced.
  • the heating may be carried out in an atmosphere of an inert gas.
  • the inert gas include nitrogen gas and argon gas.
  • the heating temperature in the heating step may be higher than the firing temperature in the first firing step, and may be higher than the temperature at which the foreign matter is decomposed.
  • the specific heating temperature may be, for example, 1450 ° C. or higher, 1600 ° C. or higher, or 1700 ° C. or higher.
  • the heating temperature may be, for example, 2000 ° C. or lower, 1950 ° C. or lower, or 1900 ° C. or lower.
  • the heating time at the above heating temperature may be, for example, 0.5 to 10 hours, or may be 1 to 5 hours.
  • FIG. 3 is a diagram illustrating an example of a heating process.
  • a plurality of setters 11 are stacked on the bottom plate 13.
  • Spacers 12 are arranged between the setters 11 adjacent to each other in the vertical direction.
  • the contact surfaces of the adjacent setters 11 are arranged so as to be separated from each other at a predetermined interval.
  • a part or all of the contact surface included in the main surface of the setter 11 is heated in the heating furnace 28 in an exposed state.
  • the same one as that of the firing furnace 25 of FIG. 1 may be used, or a different one may be used.
  • the plurality of setters 11 can be regenerated at the same time.
  • each setter 11 may be heated one by one. Further, it is not essential to use the spacer 12, and it suffices if the contact surface of each setter 11 can be heated in an exposed state. For example, using a frame having a support portion that supports the setter 11, a plurality of setters may be heated in a state of being arranged horizontally or vertically so that the contact surfaces are separated from each other.
  • the setter and the second ceramic green sheet are laminated so that the second ceramic green sheet comes into contact with at least a part of the contact surface of the setter whose foreign matter has been reduced in the heating step (second).
  • 2 laminated body is produced.
  • This second laminated body is heated in a degreasing furnace and a firing furnace to obtain a ceramic plate.
  • the degreasing furnace and the firing furnace may be the same as those used in the first firing step, or may be different.
  • the second laminated body may have the same laminated structure as the first laminated body 50 produced in the first firing step, or may have a different laminated structure.
  • the ceramic plate can be obtained by sequentially performing degreasing and firing in the same manner as in the first firing step.
  • the setter comes into contact with the second ceramic green sheet on the contact surface where foreign matter is reduced. Therefore, foreign matter on the contact surface between the second ceramic green sheet and the setter is reduced. Therefore, it is possible to prevent the ceramic plate obtained in the second firing step from having irregularities. In this way, the yield of the ceramic plate can be maintained even if the setter used in the first firing step is reused. Therefore, the production efficiency of the ceramic plate can be improved.
  • the heating step and the second firing step may be repeated.
  • the number of repetitions may be once or multiple times.
  • the setter may be heated with the contact surface with the second ceramic green sheet exposed each time the laminate is fired, or the laminate may be manufactured, the laminate may be fired, and the ceramic plate and the setter may be heated.
  • the heating step may be performed after the sorting is repeated a plurality of times.
  • the frequency of the heating step may be adjusted according to the presence or absence of foreign matter on the contact surface or the amount of foreign matter. In any case, by repeatedly regenerating and using the setter, it is possible to effectively utilize resources and reduce the manufacturing cost of the ceramic plate.
  • the ceramic plates obtained in the first firing step and the second firing step of the above-mentioned manufacturing method have the same surface quality. Therefore, it can be used for the same purpose.
  • the ceramic plate may be used as a circuit board by forming an electric circuit composed of a metal layer on one or both main surfaces, for example.
  • a laminated body in which the first setter and the ceramic green sheet are laminated so as to be in contact with each other is fired, and the contact surface of the first setter is formed on the contact surface with the ceramic green sheet.
  • the firing step can be performed in the same manner as the first firing step described above. That is, the first setter may be a commercially available ceramic sintered body or may be manufactured by a known method. Examples of the setter include those composed of at least one selected from the group consisting of boron nitride, silicon carbide, alumina, zirconia, graphite, and silicon nitride. The manufacturing procedure when the boron nitride sintered body is used as the first setter may be as described above. In the firing step, the laminate as shown in FIG. 1 may be housed in the firing furnace 25 and heated.
  • first setter the setter before firing in the firing step (first firing step)
  • second setter the setter baked in the firing step and having foreign matter adhered to the contact surface
  • the laminate obtained in the firing step is separated into a ceramic plate and a second setter, and the second setter is in a state where at least a part of the contact surface with the ceramic green sheet (ceramic plate) of the second setter is exposed. Heat the setter. As a result, the foreign matter adhering to the contact surface is volatilized or decomposed, and the foreign matter can be reduced.
  • a setter in which foreign matter is reduced by the heating step in this way may be referred to as a "third setter".
  • the heating conditions in the heating step may be the same as the heating step in the embodiment of the method for manufacturing a ceramic plate described above. Foreign matter adhering to the surface of the setter (third setter) obtained by the heating step is sufficiently reduced.
  • This setter (third setter) may have, for example, the same surface quality as the first setter.
  • the setter (third setter) thus obtained through the heating step may be used in the firing step (second firing step) instead of the first setter.
  • the second setter in which the foreign matter adheres to the contact surface is obtained again together with the ceramic plate. After this, the heating step may be performed again.
  • the used second setter can be regenerated as the third setter, and the amount of waste of the second setter can be reduced.
  • the second firing step and the heating step may be repeated a plurality of times. In this case, the reproduction of the second setter to the third setter and the production of the ceramic plate using the third setter (generation of the second setter) are repeatedly performed. Therefore, effective use of resources can be further promoted.
  • the setter manufacturing method of the present embodiment heats the used second setter used in the firing step to newly create a setter (third setter) in which foreign matter on the surface is reduced. Corresponds to the manufacturing method of. From another point of view, since the used setter is surface-treated and the used setter is regenerated, it can be said that the setter is surface-treated or the setter is regenerated.
  • the ceramic plate, the ceramic green sheet, and the setter may have a shape other than the rectangular parallelepiped shape. These may be chamfered at the corners. Further, the setter may be arranged only below the laminated body.
  • Example 1 Manufacturing of ceramic plates and regeneration of setters.
  • Example 1 A molded body (sheet material) was prepared by uniaxial pressure molding of a raw material powder containing silicon nitride powder and a sintering aid (magnesium oxide powder, yttrium oxide powder and silicon dioxide powder). This sheet material was punched out using a cutting device to form 68 ceramic green sheets having a rectangular parallelepiped shape.
  • three setters made of boron nitride having a rectangular parallelepiped shape manufactured by Denka Co., Ltd., trade name: NB-1000
  • FIG. 4 is an SEM photograph (100 times) of the main surface (before firing) of the setter.
  • FIG. 4 is an SEM photograph (100 times) of the main surface (before firing) of the setter.
  • FIG. 5 is an SEM photograph (500 times) of the main surface (before firing) of the setter taken at a higher magnification than that of FIG. As shown in FIGS. 4 and 5, no foreign matter was detected on the main surface of the setter (first setter) before firing. In the following, a laminate was produced so that the main surface and the ceramic green sheet were in contact with each other.
  • 34 ceramic green sheets were stacked between the lower setter and the central setter, and between the central setter and the upper setter.
  • a slurry for mold release was applied to the contact surface of the setter with the ceramic green sheet and one main surface of each ceramic green sheet.
  • the degreasing furnace and a firing furnace the prepared laminate was degreased and fired.
  • the degreasing temperature was 500 ° C. and the degreasing time was 30 hours.
  • the firing temperature was 1800 ° C. and the firing time was 30 hours.
  • the laminate was taken out from the firing furnace, the ceramic plate was removed from the laminate, and a pair of setters were recovered.
  • FIG. 6 is an SEM photograph (100 times) of the contact surface of the setter recovered from the laminated body.
  • FIG. 7 is an SEM photograph (500 times) of the contact surface of the setter taken at a higher magnification than that of FIG. Although the presence of foreign matter could not be confirmed visually, when the contact surface was observed at a high magnification (about 500 times) using an SEM as shown in FIG. 7, it was confirmed that the foreign matter 40 had adhered. When EDS analysis of this foreign substance was performed, Si and N were detected. From this, it was confirmed that the silicon nitride particles, which are the components contained in the ceramic green sheet (ceramic plate), were present as foreign substances on the contact surface of the setter.
  • ⁇ Heating process> As shown in FIG. 3, three setters (three second setters) confirmed to have foreign matter attached to the contact surface were stacked via spacers and placed in the firing furnace. The portion of the contact surface to which foreign matter adhered was exposed to the space inside the firing furnace without contacting the spacer. Using a calcining furnace, three setters were heated at 1850 ° C. for 2 hours in a nitrogen gas atmosphere.
  • FIG. 8 is an SEM photograph (100 times) of the contact surface of the setter after heating in the heating step.
  • FIG. 9 is an SEM photograph (500 times) of the contact surface of the setter taken at a higher magnification than that of FIG.
  • FIG. 9 shows the contact surface of the setter magnified at the same magnification as in FIG. As shown in FIG. 9, the heating process sufficiently reduced the foreign matter adhering to the contact surface.
  • Example 1 The firing step was carried out in the same manner as in Example 1 to obtain three setters (three second setters) to which foreign matter adhered to the contact surface.
  • the heating step was performed in the same manner as in Example 1 except that the contact surfaces of the three setters were stacked so as to be in contact with each other and heated in the firing furnace. That is, the three setters were fired so that the contact surfaces of the three setters were not exposed to the space inside the firing furnace.
  • FIG. 10 is an SEM photograph (100 times) of the contact surface of the setter after heating in the heating step.
  • FIG. 11 is an SEM photograph (500 times) of the contact surface of the setter taken at a higher magnification than that of FIG. As shown in FIGS. 10 and 11, foreign matter 42 that had grown and coarsened in the heating step was present on the contact surface of the setter.
  • FIG. 12 is a photograph showing an example of a convex portion on the surface of the silicon nitride plate obtained in the second firing step. In FIG. 12, a convex portion 60 formed in the central portion of the main surface of the silicon nitride plate is shown.
  • each silicon nitride plate obtained in the second firing step of Example 1 and Comparative Example 1 was evaluated. Specifically, the main surface of the silicon nitride plate was observed with a one-shot 3D shape measuring machine (model: VR-3000) manufactured by KEYENCE CORPORATION, and the size of the unevenness on the surface was examined. A defective product was determined to have a convex portion having a height of 11 ⁇ m or more or a concave portion having a depth of 11 ⁇ m or more. As a result, in Example 1, the ratio of defective products could be reduced to 1/3 or less as compared with Comparative Example 1.

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Abstract

This ceramic plate production method involves a first firing step in which a setter and a first ceramic green sheet are laminated contacting each other and are fired to obtain a ceramic plate, a heating step in which the setter is heated in a state in which at least part of the contact surface of the setter with the first ceramic green sheet is exposed, and a second firing step in which the setter and a second ceramic green sheet are laminated contacting each other in at least part of the aforementioned contact surface, and are fired to obtain a ceramic plate.

Description

セラミック板の製造方法、セッターの製造方法、及びセッターの再生方法Ceramic plate manufacturing method, setter manufacturing method, and setter regeneration method
　本開示は、セラミック板の製造方法、セッターの製造方法、及びセッターの再生方法に関する。 This disclosure relates to a method for manufacturing a ceramic plate, a method for manufacturing a setter, and a method for regenerating a setter.
　自動車、電鉄、産業用機器、及び発電関係等の分野には、大電流を制御するパワーモジュールが用いられている。パワーモジュールに搭載される回路基板は、絶縁性のセラミック板を有する。セラミック板の製造方法としては、例えば特許文献１に記載されるような以下の製造方法が知られている。すなわち、セラミックの粉末を焼結助剤等と混合した後にシート状に押出成形する工程と、打抜加工してセラミックグリーンシートを形成する工程と、セラミックグリーンシートを焼成する工程とが行われることで、セラミック板が製造される。セラミックグリーンシートの焼成工程では、セッターの上に１０～２０枚程度のセラミックグリーンシートが積層された状態でセラミックグリーンシートの焼成が行われる。 Power modules that control large currents are used in fields such as automobiles, electric railways, industrial equipment, and power generation. The circuit board mounted on the power module has an insulating ceramic plate. As a method for manufacturing a ceramic plate, for example, the following manufacturing method as described in Patent Document 1 is known. That is, a step of extruding the ceramic powder into a sheet after mixing it with a sintering aid or the like, a step of punching to form a ceramic green sheet, and a step of firing the ceramic green sheet are performed. Then, a ceramic plate is manufactured. In the firing step of the ceramic green sheet, the ceramic green sheet is fired in a state where about 10 to 20 ceramic green sheets are laminated on the setter.
特開平３－６０４６９号公報Japanese Unexamined Patent Publication No. 3-60669
　セラミックグリーンシートの焼成工程で用いられたセッターは、資源の有効活用の観点から、使用後に再生して再利用することが好ましい。そこで、本開示では、セッターを再生することによって、セラミック板の生産効率を向上することが可能なセラミック板の製造方法を提供する。また、資源を有効活用することが可能なセッターの製造方法及びセッターの再生方法を提供する。 From the viewpoint of effective utilization of resources, it is preferable that the setter used in the firing process of the ceramic green sheet is recycled and reused after use. Therefore, the present disclosure provides a method for manufacturing a ceramic plate, which can improve the production efficiency of the ceramic plate by regenerating the setter. Further, the present invention provides a method for manufacturing a setter and a method for regenerating the setter, which can effectively utilize resources.
　セラミックグリーンシートの焼成にセッターを繰り返し使用すると、焼成前のセッターの対向面が平滑であっても、セラミック板の表面に凹凸が発生する場合がある。本発明者らの検討によれば、セッターに付着していた、セラミックグリーンシート又はセラミック板の含有成分に起因する微小な異物が、焼成によって成長して粗大粒子となり、この粗大粒子の形状が転写されてセラミック板の表面に凹凸を生じさせることが分かった。 When the setter is repeatedly used for firing the ceramic green sheet, unevenness may occur on the surface of the ceramic plate even if the facing surface of the setter before firing is smooth. According to the study by the present inventors, minute foreign substances adhering to the setter due to the components contained in the ceramic green sheet or the ceramic plate grow to become coarse particles by firing, and the shape of the coarse particles is transferred. It was found that the surface of the ceramic plate was uneven.
　そこで、本開示の一側面に係るセラミック板の製造方法は、セッターと第１セラミックグリーンシートとが互いに接触するように積層して焼成しセラミック板を得る第１焼成工程と、第１セラミックグリーンシートとのセッターの接触面の少なくとも一部が露出した状態でセッターを加熱する加熱工程と、セッターと第２セラミックグリーンシートとが上記接触面の少なくとも一部において互いに接触するように積層して焼成しセラミック板を得る第２焼成工程と、を有する。 Therefore, the method for manufacturing a ceramic plate according to one aspect of the present disclosure includes a first firing step of laminating and firing the setter and the first ceramic green sheet so as to be in contact with each other to obtain a ceramic plate, and a first ceramic green sheet. The heating step of heating the setter with at least a part of the contact surface of the setter exposed and the second ceramic green sheet are laminated and fired so as to be in contact with each other at at least a part of the contact surface. It has a second firing step of obtaining a ceramic plate.
　上述の製造方法では、第１セラミックグリーンシートと接触していた、セッターの接触面の少なくとも一部が露出した状態で当該セッターを加熱している。このようにセッターを加熱することで、第１セラミックグリーンシートに由来する微小な異物が低減され、第２焼成工程で得られるセラミック板に凹凸が生じることを抑制できる。このように、セッターを繰り返し使用してもセラミック板の歩留まりを維持できることから、セラミック板の生産効率を向上することができる。 In the above-mentioned manufacturing method, the setter is heated with at least a part of the contact surface of the setter exposed, which was in contact with the first ceramic green sheet. By heating the setter in this way, minute foreign substances derived from the first ceramic green sheet can be reduced, and unevenness can be suppressed on the ceramic plate obtained in the second firing step. As described above, since the yield of the ceramic plate can be maintained even if the setter is repeatedly used, the production efficiency of the ceramic plate can be improved.
　加熱工程では、上記接触面に付着する、セッターの含有成分とは異なる成分を含む異物が分解する温度以上に加熱してもよい。これによって、接触面に付着する異物を十分に低減し、セラミック板の表面に発生する凹凸を十分に低減することができる。したがって、セラミック板の歩留まりを一層向上することができる。本開示における「セッターの含有成分」とは、セラミック板の製造方法に用いられる前から、元々セッターに含まれていた成分をいう。すなわち、未使用のセッターに含まれる成分（構成成分）である。例えば、窒化ホウ素焼結体で構成されるセッターの含有成分は、窒化ホウ素である。 In the heating step, the temperature may be higher than the temperature at which the foreign matter containing a component different from the component contained in the setter that adheres to the contact surface is decomposed. As a result, foreign matter adhering to the contact surface can be sufficiently reduced, and unevenness generated on the surface of the ceramic plate can be sufficiently reduced. Therefore, the yield of the ceramic plate can be further improved. The "component contained in the setter" in the present disclosure refers to a component originally contained in the setter before it is used in the method for manufacturing a ceramic plate. That is, it is a component (constituent component) contained in an unused setter. For example, the component contained in the setter composed of the boron nitride sintered body is boron nitride.
　第１焼成工程では、上記セッターを含む複数のセッターと、上記第１セラミックグリーンシートを含む複数の第１セラミックグリーンシートと、がそれぞれ接触するように積層して焼成してよい。このとき、加熱工程では、複数のセッターの、第１セラミックグリーンシートと接触していた接触面同士を互いに離した状態で複数のセッターを加熱してもよい。これによって、複数のセッターを一緒に加熱して再生することができる。したがって、セラミック板の生産効率を一層向上することができる。 In the first firing step, a plurality of setters including the above setter and a plurality of first ceramic green sheets including the first ceramic green sheet may be laminated and fired so as to be in contact with each other. At this time, in the heating step, the plurality of setters may be heated with the contact surfaces of the plurality of setters in contact with the first ceramic green sheet separated from each other. This allows a plurality of setters to be heated and regenerated together. Therefore, the production efficiency of the ceramic plate can be further improved.
　第１セラミックグリーンシートは窒化ケイ素を含み、加熱工程では、不活性ガス雰囲気中でセッターを１４５０～２０００℃で加熱してもよい。これによって、異物に含まれる窒化ケイ素の分解が円滑に進行し、加熱工程の所要時間を短縮することができる。また、セッターの接触面における異物を十分に低減し、第２焼成工程で得られるセラミック板の表面に発生する凹凸を一層低減できる。 The first ceramic green sheet contains silicon nitride, and in the heating step, the setter may be heated at 1450 to 2000 ° C. in an atmosphere of an inert gas. As a result, the decomposition of silicon nitride contained in the foreign matter proceeds smoothly, and the time required for the heating step can be shortened. In addition, foreign matter on the contact surface of the setter can be sufficiently reduced, and unevenness generated on the surface of the ceramic plate obtained in the second firing step can be further reduced.
　本開示の一側面に係るセッターの製造方法は、第１セッターとセラミックグリーンシートとが互いに接触するように積層して焼成し、セラミックグリーンシートとの接触面に第１セッターの含有成分とは異なる成分を含む異物が付着した第２セッターを得る焼成工程と、上記接触面の少なくとも一部が露出した状態で第２セッターを加熱して、上記接触面における異物を低減する加熱工程と、を有する。 The method for manufacturing a setter according to one aspect of the present disclosure is different from the components contained in the first setter on the contact surface with the ceramic green sheet by laminating and firing so that the first setter and the ceramic green sheet are in contact with each other. It has a firing step of obtaining a second setter to which foreign matter containing a component is attached, and a heating step of heating the second setter with at least a part of the contact surface exposed to reduce foreign matter on the contact surface. ..
　上述の製造方法では、焼成工程においてセラミックグリーンシートとの接触面に異物が付着した第２セッターを加熱する加熱工程を有する。加熱工程では、接触面の少なくとも一部が露出した状態で第２セッターを加熱して、接触面における異物を低減している。異物を低減して得られるセッター（第３セッター）は、再びセラミックグリーンシートと接触するように積層して焼成することができる。このように上記セッターの製造方法では、異物が付着した第２セッターから、異物が低減されたセッター（第３セッター）を製造することによってセッターの廃棄量を低減し、資源を有効活用することができる。 The above-mentioned manufacturing method has a heating step of heating the second setter in which foreign matter adheres to the contact surface with the ceramic green sheet in the firing step. In the heating step, the second setter is heated with at least a part of the contact surface exposed to reduce foreign matter on the contact surface. The setter (third setter) obtained by reducing the amount of foreign matter can be laminated and fired so as to be in contact with the ceramic green sheet again. As described above, in the above-mentioned manufacturing method of the setter, the waste amount of the setter can be reduced and the resources can be effectively utilized by manufacturing the setter (third setter) in which the foreign matter is reduced from the second setter to which the foreign matter is attached. can.
　加熱工程では、異物が分解する温度以上に加熱してもよい。これによって、接触面に付着していた異物を十分且つ円滑に低減することができる。したがって、効率よくセッターを製造することができる。 In the heating step, the temperature may be higher than the temperature at which the foreign matter decomposes. As a result, foreign matter adhering to the contact surface can be sufficiently and smoothly reduced. Therefore, the setter can be efficiently manufactured.
　焼成工程では、上記第１セッターを含む複数の第１セッターと、上記セラミックグリーンシートを含む複数のセラミックグリーンシートとがそれぞれ接触するように積層して焼成し、上記第２セッターを含む複数の第２セッターを得てもよい。このとき、加熱工程では、複数の第２セッターの、セラミックグリーンシートと接触していた接触面同士を互いに離した状態で複数の第２セッターを加熱してもよい。これによって、複数の第２セッターを一緒に加熱して複数のセッターを同時に製造することができる。したがって、セッターの生産効率を向上することができる。 In the firing step, a plurality of first setters including the first setter and a plurality of ceramic green sheets including the ceramic green sheet are laminated and fired so as to be in contact with each other, and a plurality of second setsters including the second setter are fired. You may get 2 setters. At this time, in the heating step, the plurality of second setters may be heated with the contact surfaces of the plurality of second setters in contact with the ceramic green sheet separated from each other. Thereby, a plurality of second setters can be heated together to produce a plurality of setters at the same time. Therefore, the production efficiency of the setter can be improved.
　上記セラミックグリーンシートは窒化ケイ素を含み、加熱工程では、不活性ガス雰囲気中で第２セッターを１４５０～２０００℃で加熱してもよい。これによって、異物に含まれる窒化ケイ素の分解が円滑に進行し、加熱工程の所要時間を短縮することができる。また、異物が十分に低減されたセッターを得ることができる。 The ceramic green sheet contains silicon nitride, and in the heating step, the second setter may be heated at 1450 to 2000 ° C. in an atmosphere of an inert gas. As a result, the decomposition of silicon nitride contained in the foreign matter proceeds smoothly, and the time required for the heating step can be shortened. In addition, it is possible to obtain a setter in which foreign matter is sufficiently reduced.
　本開示の一側面に係るセッターの再生方法は、第１セッターとセラミックグリーンシートとが互いに接触するように積層して焼成し、セラミックグリーンシートとの接触面に第１セッターの含有成分とは異なる成分を含む異物が付着した第２セッターを得る焼成工程と、接触面の少なくとも一部が露出した状態で第２セッターを加熱して、接触面における異物を低減する加熱工程と、を有する。 The method for regenerating a setter according to one aspect of the present disclosure is different from the components contained in the first setter on the contact surface with the ceramic green sheet by laminating and firing so that the first setter and the ceramic green sheet are in contact with each other. It has a firing step of obtaining a second setter to which foreign matter containing a component is attached, and a heating step of heating the second setter with at least a part of the contact surface exposed to reduce foreign matter on the contact surface.
　上述の再生方法では、焼成工程においてセラミックグリーンシートとの接触面に異物が付着した第２セッターを加熱する加熱工程を有する。加熱工程では、接触面の少なくとも一部が露出した状態で第２セッターを加熱して、接触面における異物を低減している。異物を低減して得られるセッター（第３セッター）は、再びセラミックグリーンシートと接触するように積層して焼成することができる。このように上記セッターの再生方法では、異物が付着した第２セッターから、異物が低減されたセッター（第３セッター）を再生することによってセッターの廃棄量を低減し、資源を有効活用することができる。 The above-mentioned regeneration method has a heating step of heating the second setter in which foreign matter adheres to the contact surface with the ceramic green sheet in the firing step. In the heating step, the second setter is heated with at least a part of the contact surface exposed to reduce foreign matter on the contact surface. The setter (third setter) obtained by reducing the amount of foreign matter can be laminated and fired so as to be in contact with the ceramic green sheet again. As described above, in the above-mentioned method for regenerating the setter, the waste amount of the setter can be reduced and the resources can be effectively utilized by regenerating the setter (third setter) in which the foreign matter is reduced from the second setter to which the foreign matter is attached. can.
　本開示によれば、セッターを再生することによって、セラミック板の生産効率を向上することが可能なセラミック板の製造方法を提供することができる。また、資源を有効活用することが可能なセッターの製造方法及びセッターの再生方法を提供することができる。 According to the present disclosure, it is possible to provide a method for manufacturing a ceramic plate capable of improving the production efficiency of the ceramic plate by regenerating the setter. Further, it is possible to provide a method for manufacturing a setter and a method for regenerating the setter that can effectively utilize resources.
積層体の焼成工程の一例を説明する図である。It is a figure explaining an example of the firing process of a laminated body. 窒化ホウ素焼結体で構成されるセッターの接触面に付着した異物（窒化ホウ素粒子）の例を示すＳＥＭ写真である。6 is an SEM photograph showing an example of foreign matter (boron nitride particles) adhering to the contact surface of a setter made of a boron nitride sintered body. 加熱工程の一例を示す図である。It is a figure which shows an example of a heating process. 実施例１で用いたセッターの主面（焼成前）を示すＳＥＭ写真である。It is an SEM photograph which shows the main surface (before firing) of the setter used in Example 1. FIG. 図４よりも高い倍率で撮影された、図４の主面を示すＳＥＭ写真である。6 is an SEM photograph showing the main surface of FIG. 4 taken at a higher magnification than that of FIG. 実施例１の第１焼成工程後のセッターの接触面を示すＳＥＭ写真である。It is an SEM photograph which shows the contact surface of the setter after the 1st firing step of Example 1. FIG. 図６よりも高い倍率で撮影された、図６の接触面を示すＳＥＭ写真である。6 is an SEM photograph showing the contact surface of FIG. 6 taken at a higher magnification than that of FIG. 実施例１の加熱工程後のセッターの接触面を示すＳＥＭ写真である。It is an SEM photograph which shows the contact surface of the setter after the heating process of Example 1. FIG. 図８よりも高い倍率で撮影された、図８の接触面を示すＳＥＭ写真である。6 is an SEM photograph showing the contact surface of FIG. 8 taken at a higher magnification than that of FIG. 比較例１の加熱工程後のセッターの接触面を示すＳＥＭ写真である。6 is an SEM photograph showing the contact surface of the setter after the heating step of Comparative Example 1. 図１１よりも高い倍率で撮影された、図１０の接触面を示すＳＥＭ写真である。11 is an SEM photograph showing the contact surface of FIG. 10 taken at a higher magnification than that of FIG. 11. 窒化ケイ素板の表面における凸部の例を示す写真である。It is a photograph which shows the example of the convex part on the surface of a silicon nitride plate.
　以下、場合により図面を参照して、本開示の実施形態を説明する。ただし、以下の実施形態は、本開示を説明するための例示であり、本開示を以下の内容に限定する趣旨ではない。説明において、同一要素又は同一機能を有する要素には同一の符号を付し、重複する説明を省略する。また、説明に使用される上下左右等の位置関係は、特に断らない限り、図面に示す位置関係に基づくものとする。 Hereinafter, embodiments of the present disclosure will be described with reference to the drawings as the case may be. However, the following embodiments are examples for explaining the present disclosure, and are not intended to limit the present disclosure to the following contents. In the description, the same elements or elements having the same function are designated by the same reference numerals, and duplicate description will be omitted. In addition, the positional relationship such as up, down, left, and right used in the explanation shall be based on the positional relationship shown in the drawings unless otherwise specified.
　本開示の一側面に係るセラミック板の製造方法は、セッターとセラミックグリーンシート（第１セラミックグリーンシート）とが互いに接触するように積層された積層体（第１積層体）を焼成してセラミック板を得る第１焼成工程と、第１積層体を、セッターとセラミック板とに分別し、セラミックグリーンシートと接触していたセッターの接触面の少なくとも一部が露出した状態でセッターを加熱する加熱工程と、セッターとセラミックグリーンシート（第２セラミックグリーンシート）とが上記接触面の少なくとも一部において互いに接触するように積層された積層体（第２積層体）を焼成しセラミック板を得る第２焼成工程と、を有する。 In the method for manufacturing a ceramic plate according to one aspect of the present disclosure, a laminated body (first laminated body) laminated so that a setter and a ceramic green sheet (first ceramic green sheet) are in contact with each other is fired to obtain a ceramic plate. The first firing step and the heating step of separating the first laminated body into a setter and a ceramic plate and heating the setter with at least a part of the contact surface of the setter in contact with the ceramic green sheet exposed. And the second firing to obtain a ceramic plate by firing the laminated body (second laminated body) in which the setter and the ceramic green sheet (second ceramic green sheet) are laminated so as to be in contact with each other at at least a part of the contact surface. It has a process.
　第１セラミックグリーンシート及び第２セラミックグリーンシートは、セッターに接触するように積層されるセラミックグリーンシートである。第１焼成工程及び第２焼成工程でセッターと接触するように積層される第１セラミックグリーンシート及び第２セラミックグリーンシートは、例えば以下の手順で製造する。まず、セラミック粉末、焼結助剤及びバインダを含む原料スラリーを形成する。セラミックとしては、特に制限されず、例えば、炭化物、酸化物及び窒化物等が挙げられる。具体的には、炭化ケイ素、アルミナ、窒化ケイ素、窒化アルミニウム及び窒化ホウ素等が挙げられる。バインダは有機成分を含むものが挙げられる。 The first ceramic green sheet and the second ceramic green sheet are ceramic green sheets laminated so as to be in contact with the setter. The first ceramic green sheet and the second ceramic green sheet laminated so as to be in contact with the setter in the first firing step and the second firing step are manufactured by, for example, the following procedure. First, a raw material slurry containing a ceramic powder, a sintering aid and a binder is formed. The ceramic is not particularly limited, and examples thereof include carbides, oxides, and nitrides. Specific examples thereof include silicon carbide, alumina, silicon nitride, aluminum nitride and boron nitride. Binders include those containing organic components.
　原料スラリーをドクターブレード法、カレンダー法、又は押し出し法等によって離型フィルム上に所定の厚みで塗布する。その後、塗布された原料スラリーを乾燥させて離型フィルムから剥がすことによって、第１セラミックグリーンシート及び第２セラミックグリーンシートが得られる。第１セラミックグリーンシート及び第２セラミックグリーンシートは、例えば切断等によって所望の形状に加工してよい。第１セラミックグリーンシート及び第２セラミックグリーンシートの材質及び形状は、同一であってもよいし、異なっていてもよい。 Apply the raw material slurry to a predetermined thickness on the release film by the doctor blade method, calendar method, extrusion method, etc. Then, the applied raw material slurry is dried and peeled off from the release film to obtain a first ceramic green sheet and a second ceramic green sheet. The first ceramic green sheet and the second ceramic green sheet may be processed into a desired shape by, for example, cutting. The materials and shapes of the first ceramic green sheet and the second ceramic green sheet may be the same or different.
　セッターは、例えば市販のセラミック焼結体を購入してもよいし、公知の方法で製造してもよい。セッターは、例えば、窒化ホウ素、炭化ケイ素、アルミナ、ジルコニア、グラファイト、及び窒化ケイ素からなる群より選ばれる少なくとも一種を含むものが挙げられる。これらのうち、窒化ホウ素製のセッターは、耐熱性と良好な切削性を兼ね備えるため、好適に用いられる。なお、焼成後のセッターとセラミック板との接着を抑制する観点から、セッターの材質は、セラミック板の材質とは異なるものであってよい。 As the setter, for example, a commercially available ceramic sintered body may be purchased, or may be manufactured by a known method. Examples of the setter include those containing at least one selected from the group consisting of boron nitride, silicon carbide, alumina, zirconia, graphite, and silicon nitride. Of these, a setter made of boron nitride is preferably used because it has both heat resistance and good machinability. The material of the setter may be different from the material of the ceramic plate from the viewpoint of suppressing the adhesion between the setter and the ceramic plate after firing.
　セッターとして、窒化ホウ素焼結体を用いる場合、以下の手順で製造することができる。まず、原料として、六方晶窒化ホウ素粉末を用いて成形体を作製する。必要に応じて、成形前に六方晶窒化ホウ素粉末に焼結助剤を配合してもよい。焼結助剤としては、酸化マグネシウム、酸化カルシウム等のアルカリ土類酸化物、酸化アルミニウム、酸化ケイ素、酸化イットリウム等の希土類酸化物、及び、スピネル等の複合酸化物が挙げられる。成形は、一軸加圧成形とＣＩＰ成形を行ってよい。一軸加圧成形は３～２０ＭＰａで行ってよい。ＣＩＰ成形は、５０～３００ＭＰａで行ってよい。 When a boron nitride sintered body is used as the setter, it can be manufactured by the following procedure. First, a molded product is produced using hexagonal boron nitride powder as a raw material. If necessary, a sintering aid may be added to the hexagonal boron nitride powder before molding. Examples of the sintering aid include alkaline earth oxides such as magnesium oxide and calcium oxide, rare earth oxides such as aluminum oxide, silicon oxide and yttrium oxide, and composite oxides such as spinel. The molding may be performed by uniaxial pressure molding and CIP molding. Uniaxial pressure molding may be performed at 3 to 20 MPa. CIP molding may be performed at 50 to 300 MPa.
　得られた成形体の焼成を行って窒化ホウ素焼結体を得る。焼成は、非酸化性雰囲気下、昇温速度を１５０℃／ｈｒ以下、最高温度を１８００～２２００℃、この温度範囲における保持時間を５時間以上の条件で行ってよい。非酸化性雰囲気としては、例えば窒素、アンモニア等の窒化性ガス雰囲気が挙げられる。窒化ホウ素焼結体の密度は１６００ｋｇ／ｍ３以上であってよい。なお、窒化ホウ素焼結体の製造方法は上述の方法に限定されない。例えば、ホットプレス法によって製造してもよい。窒化ホウ素焼結体以外のセラミック焼結体は公知の方法で製造することができる。 The obtained molded product is fired to obtain a boron nitride sintered body. The firing may be carried out under the conditions of a non-oxidizing atmosphere, a heating rate of 150 ° C./hr or less, a maximum temperature of 1800 to 2200 ° C., and a holding time of 5 hours or more in this temperature range. Examples of the non-oxidizing atmosphere include a nitride gas atmosphere such as nitrogen and ammonia. The density of the boron nitride sintered body may be 1600 kg / m 3 or more. The method for producing the boron nitride sintered body is not limited to the above method. For example, it may be manufactured by a hot press method. Ceramic sintered bodies other than the boron nitride sintered body can be produced by a known method.
　このようにして得られたセッターと第１セラミックグリーンシートとが互いに接触するように積層して積層体を作製する。積層体を構成するセッター及びセラミックグリーンシートの枚数に特に制限はない。積層体は、例えば、一対のセッターの間に、第１セラミックグリーンシートを含む複数枚（例えば５０～１００枚）のセラミックグリーンシートを挟んでいてよい。また、１枚のセッターと第１セラミックグリーンシートを含む複数枚のセラミックグリーンシートとが交互に並んでいてもよい。このように、複数枚のセラミックグリーンシートを第１焼成工程で焼成することによって、複数のセラミック板を同時に製造することができる。 The setter thus obtained and the first ceramic green sheet are laminated so as to be in contact with each other to produce a laminated body. The number of setters and ceramic green sheets constituting the laminate is not particularly limited. As the laminate, for example, a plurality of (for example, 50 to 100) ceramic green sheets including the first ceramic green sheet may be sandwiched between a pair of setters. Further, one setter and a plurality of ceramic green sheets including the first ceramic green sheet may be arranged alternately. As described above, by firing a plurality of ceramic green sheets in the first firing step, a plurality of ceramic plates can be manufactured at the same time.
　第１セラミックグリーンシートとともに積層されるセラミックグリーンシートの材質及び形状は、第１セラミックグリーンシートと同一であってもよいし、異なっていてもよい。セラミックグリーンシート（第１セラミックグリーンシート）の主面には、焼成の際に隣り合うセラミックグリーンシート同士が接着することを抑制するため、離型剤が塗布されていてもよい。また、セッターの第１セラミックグリーンシートの主面との対向面にも、離型剤が塗布されていてもよい。離型剤の含有成分としては、窒化ホウ素等のセラミック粉末、黒鉛粉末、及びバインダ等が挙げられる。 The material and shape of the ceramic green sheet laminated together with the first ceramic green sheet may be the same as or different from that of the first ceramic green sheet. A mold release agent may be applied to the main surface of the ceramic green sheet (first ceramic green sheet) in order to prevent the adjacent ceramic green sheets from adhering to each other during firing. Further, the mold release agent may be applied to the surface of the setter facing the main surface of the first ceramic green sheet. Examples of the component contained in the release agent include ceramic powder such as boron nitride, graphite powder, and binder.
　図１は、積層体の第１焼成工程の一例を説明する図である。積層体５０は、３枚のセッター１０と、複数のセラミックグリーンシート３０を含む。複数のセラミックグリーンシート３０は、３枚のセッター１０に隣接する４枚の第１セラミックグリーンシート３０ａを含む。３枚のセッター１０のうち、一対のセッター１０Ａ，１０Ｂは、積層体５０の最下部と最上部に積層されている。したがって、セッター１０Ａ、１０Ｂでは、一方の主面が第１セラミックグリーンシート３０ａと接触している。残りのセッター１０Ｃは、積層体５０の中央部に積層されている。したがって、セッター１０Ｃは、両方の主面が第１セラミックグリーンシート３０ａと接触している。このように、第１セラミックグリーンシート３０ａとセッター１０とが接触するセッター１０の接触面は、一方又は両方の主面に含まれる。 FIG. 1 is a diagram illustrating an example of the first firing step of the laminated body. The laminate 50 includes three setters 10 and a plurality of ceramic green sheets 30. The plurality of ceramic green sheets 30 include four first ceramic green sheets 30a adjacent to the three setters 10. Of the three setters 10, the pair of setters 10A and 10B are laminated at the bottom and top of the laminated body 50. Therefore, in the setters 10A and 10B, one main surface is in contact with the first ceramic green sheet 30a. The remaining setter 10C is laminated in the central portion of the laminated body 50. Therefore, both main surfaces of the setter 10C are in contact with the first ceramic green sheet 30a. As described above, the contact surface of the setter 10 in which the first ceramic green sheet 30a and the setter 10 come into contact with each other is included in one or both main surfaces.
　図１に示すように、積層体５０を、脱脂炉２０に収容し、例えば３００℃～７００℃に加熱する。これによって、セラミックグリーンシート３０に含まれるバインダが除去される。続いて、脱脂された積層体５０を焼成炉２５に収容して、１６００℃～２０００℃に加熱する。これによって、セラミックグリーンシートが焼成され、セラミック板が得られる。なお、脱脂で用いる脱脂炉２０と焼成で用いる焼成炉２５は同一炉であってもよいし、異なる炉であってもよい。また、加熱の温度、時間及び雰囲気は、セラミックグリーンシートの組成に応じて適宜調整してよい。 As shown in FIG. 1, the laminated body 50 is housed in a degreasing furnace 20 and heated to, for example, 300 ° C. to 700 ° C. As a result, the binder contained in the ceramic green sheet 30 is removed. Subsequently, the degreased laminate 50 is housed in the firing furnace 25 and heated to 1600 ° C to 2000 ° C. As a result, the ceramic green sheet is fired and a ceramic plate is obtained. The degreasing furnace 20 used for degreasing and the firing furnace 25 used for firing may be the same furnace or different furnaces. Further, the heating temperature, time and atmosphere may be appropriately adjusted according to the composition of the ceramic green sheet.
　加熱工程では、第１焼成工程で焼成した積層体（第１積層体）を、セラミック板とセッターに分別する。得られたセラミック板は必要に応じて加工を行って、例えば回路基板にしてもよい。分別したセッターの第１セラミックグリーンシート３０ａ（セラミック板）と接触していた接触面には、セッターの含有成分とは異なる成分を含む粒状の異物が付着している。異物に含まれる成分としては、例えば、セラミックグリーンシート又はセラミック板の含有成分、及び、これらの含有成分とセッターの含有成分との反応生成物が挙げられる。異物の粒径は、セッターを構成する粒子よりも大きくてよい。すなわち、異物は粗粒であってもよい。 In the heating step, the laminated body (first laminated body) fired in the first firing step is separated into a ceramic plate and a setter. The obtained ceramic plate may be processed as necessary to form, for example, a circuit board. Granular foreign matter containing a component different from the component contained in the setter adheres to the contact surface that has been in contact with the first ceramic green sheet 30a (ceramic plate) of the separated setter. Examples of the components contained in the foreign substance include components contained in a ceramic green sheet or a ceramic plate, and reaction products of these components and components contained in a setter. The particle size of the foreign matter may be larger than the particles constituting the setter. That is, the foreign matter may be coarse particles.
　図２は、窒化ホウ素焼結体で構成されるセッターの接触面に付着した異物（窒化ホウ素粒子）の例を示すＳＥＭ写真である。異物の組成は、ＥＤＳ分析によって測定することができる。セッターが窒化ホウ素焼結体で構成され、異物が窒化ケイ素粒子である場合、両者の色が近似しているため、肉眼では異物を見つけることが難しい。このような場合、図２に示すとおりＳＥＭ観察を高倍率（例えば５００倍以上）で行うことによって異物の有無を判断することができる。 FIG. 2 is an SEM photograph showing an example of foreign matter (boron nitride particles) adhering to the contact surface of a setter composed of a boron nitride sintered body. The composition of foreign matter can be measured by EDS analysis. When the setter is composed of a boron nitride sintered body and the foreign matter is silicon nitride particles, it is difficult to find the foreign matter with the naked eye because the colors of both are similar. In such a case, the presence or absence of a foreign substance can be determined by performing SEM observation at a high magnification (for example, 500 times or more) as shown in FIG.
　このような異物が接触面に付着しているセッターを、接触面が露出した状態で加熱する。これによって接触面に付着している異物を揮発又は分解して低減することができる。加熱は、不活性ガス雰囲気中で行ってよい。不活性ガスとしては、例えば、窒素ガス、及びアルゴンガスが挙げられる。加熱工程における加熱温度は、第１焼成工程における焼成温度よりも高くてよく、異物が分解する温度以上であってよい。 The setter with such foreign matter adhering to the contact surface is heated with the contact surface exposed. As a result, foreign matter adhering to the contact surface can be volatilized or decomposed and reduced. The heating may be carried out in an atmosphere of an inert gas. Examples of the inert gas include nitrogen gas and argon gas. The heating temperature in the heating step may be higher than the firing temperature in the first firing step, and may be higher than the temperature at which the foreign matter is decomposed.
　具体的な加熱温度は、例えば、１４５０℃以上であってよく、１６００℃以上であってよく、１７００℃以上であってもよい。加熱温度を高くすることによって、異物の分解を促進し、異物が十分に低減された主面（接触面）を有するセッターを得ることができる。このような加熱温度であれば、セラミック板として窒化ケイ素板を製造する場合に、セッターの接触面に異物として付着する窒化ケイ素粒子を十分に低減することできる。加熱温度は、例えば、２０００℃以下であってよく、１９５０℃以下であってよく、１９００℃以下であってもよい。これによって過剰な加熱を抑制してセッターのダメージを低減するとともに、エネルギー効率を向上することができる。上記加熱温度における加熱時間は、例えば０．５～１０時間であってよく、１～５時間であってもよい。 The specific heating temperature may be, for example, 1450 ° C. or higher, 1600 ° C. or higher, or 1700 ° C. or higher. By increasing the heating temperature, it is possible to obtain a setter having a main surface (contact surface) in which the decomposition of foreign matter is promoted and the foreign matter is sufficiently reduced. At such a heating temperature, when a silicon nitride plate is manufactured as a ceramic plate, the silicon nitride particles adhering to the contact surface of the setter as foreign matter can be sufficiently reduced. The heating temperature may be, for example, 2000 ° C. or lower, 1950 ° C. or lower, or 1900 ° C. or lower. As a result, excessive heating can be suppressed, damage to the setter can be reduced, and energy efficiency can be improved. The heating time at the above heating temperature may be, for example, 0.5 to 10 hours, or may be 1 to 5 hours.
　図３は、加熱工程の一例を説明する図である。加熱炉２８中には、底板１３の上に、複数のセッター１１が積み上げられている。上下方向に隣り合うセッター１１の間にはスペーサ１２が配置されている。これによって、隣り合うセッター１１の接触面同士は所定の間隔で離れるようにして配置される。その結果、セッター１１の主面に含まれる接触面の一部又は全部は、露出した状態で加熱炉２８中において加熱される。加熱炉２８は、図１の焼成炉２５と同一のものを用いてもよく、異なるものを用いてもよい。加熱炉２８において複数のセッター１１を同時に加熱することによって、複数のセッター１１を同時に再生することができる。 FIG. 3 is a diagram illustrating an example of a heating process. In the heating furnace 28, a plurality of setters 11 are stacked on the bottom plate 13. Spacers 12 are arranged between the setters 11 adjacent to each other in the vertical direction. As a result, the contact surfaces of the adjacent setters 11 are arranged so as to be separated from each other at a predetermined interval. As a result, a part or all of the contact surface included in the main surface of the setter 11 is heated in the heating furnace 28 in an exposed state. As the heating furnace 28, the same one as that of the firing furnace 25 of FIG. 1 may be used, or a different one may be used. By heating a plurality of setters 11 at the same time in the heating furnace 28, the plurality of setters 11 can be regenerated at the same time.
　図３のように複数のセッター１１を同時に加熱することは必須ではなく、セッター１１を１枚ずつ加熱してもよい。また、スペーサ１２を用いることは必須ではなく、各セッター１１の接触面が露出した状態で加熱できればよい。例えば、セッター１１を支持する支持部を有する枠体を用いて、複数のセッターを接触面同士が互いに離れるように水平方向又は鉛直方向に沿って並べた状態で加熱してもよい。 It is not essential to heat a plurality of setters 11 at the same time as shown in FIG. 3, and the setters 11 may be heated one by one. Further, it is not essential to use the spacer 12, and it suffices if the contact surface of each setter 11 can be heated in an exposed state. For example, using a frame having a support portion that supports the setter 11, a plurality of setters may be heated in a state of being arranged horizontally or vertically so that the contact surfaces are separated from each other.
　第２焼成工程では、加熱工程で異物が低減されたセッターの接触面の少なくとも一部に第２セラミックグリーンシートが接触するように、セッターと第２セラミックグリーンシートとを積層して積層体（第２積層体）を作製する。この第２積層体を、脱脂炉及び焼成炉で加熱してセラミック板を得る。脱脂炉及び焼成炉は、第１焼成工程で用いたものと同じであってよく、異なっていてもよい。第２積層体は、第１焼成工程で作製した第１積層体５０と同じ積層構造を有していてもよいし、異なる積層構造を有していてもよい。第２焼成工程では、第１焼成工程と同様に脱脂及び焼成を順次行ってセラミック板を得ることができる。 In the second firing step, the setter and the second ceramic green sheet are laminated so that the second ceramic green sheet comes into contact with at least a part of the contact surface of the setter whose foreign matter has been reduced in the heating step (second). 2 laminated body) is produced. This second laminated body is heated in a degreasing furnace and a firing furnace to obtain a ceramic plate. The degreasing furnace and the firing furnace may be the same as those used in the first firing step, or may be different. The second laminated body may have the same laminated structure as the first laminated body 50 produced in the first firing step, or may have a different laminated structure. In the second firing step, the ceramic plate can be obtained by sequentially performing degreasing and firing in the same manner as in the first firing step.
　第２積層体において、セッターは、異物が低減された接触面において第２セラミックグリーンシートと接触する。このため、第２セラミックグリーンシートとセッターの接触面における異物が低減されている。したがって、第２焼成工程で得られるセラミック板に凹凸が生じることを抑制できる。このように、第１焼成工程で使用済みのセッターを再利用しても、セラミック板の歩留まりを維持することができる。したがって、セラミック板の生産効率を向上することができる。 In the second laminated body, the setter comes into contact with the second ceramic green sheet on the contact surface where foreign matter is reduced. Therefore, foreign matter on the contact surface between the second ceramic green sheet and the setter is reduced. Therefore, it is possible to prevent the ceramic plate obtained in the second firing step from having irregularities. In this way, the yield of the ceramic plate can be maintained even if the setter used in the first firing step is reused. Therefore, the production efficiency of the ceramic plate can be improved.
　第２焼成工程の後、加熱工程及び第２焼成工程を繰り返し行ってよい。繰り返し回数は１回でも複数回でもよい。セッターは、積層体として一度焼成される毎に、第２セラミックグリーンシートとの接触面を露出させた状態で加熱してもよいし、積層体の作製、積層体の焼成及びセラミック板とセッターの分別を複数回繰り返した後に加熱工程を行ってもよい。加熱工程の頻度は、接触面における異物の有無又は異物の量に応じて調整してよい。いずれにしても、セッターを繰り返して再生し使用することで資源の有効活用を図るとともに、セラミック板の製造コストを低減することができる。 After the second firing step, the heating step and the second firing step may be repeated. The number of repetitions may be once or multiple times. The setter may be heated with the contact surface with the second ceramic green sheet exposed each time the laminate is fired, or the laminate may be manufactured, the laminate may be fired, and the ceramic plate and the setter may be heated. The heating step may be performed after the sorting is repeated a plurality of times. The frequency of the heating step may be adjusted according to the presence or absence of foreign matter on the contact surface or the amount of foreign matter. In any case, by repeatedly regenerating and using the setter, it is possible to effectively utilize resources and reduce the manufacturing cost of the ceramic plate.
　上述の製造方法の第１焼成工程と第２焼成工程で得られるセラミック板は、同等の表面品質を有する。このため、同様の用途に用いることができる。セラミック板は、例えば、一方又は両方の主面に金属層で構成される電気回路を形成して回路基板としてよい。 The ceramic plates obtained in the first firing step and the second firing step of the above-mentioned manufacturing method have the same surface quality. Therefore, it can be used for the same purpose. The ceramic plate may be used as a circuit board by forming an electric circuit composed of a metal layer on one or both main surfaces, for example.
　一実施形態に係るセッターの製造方法（再生方法）は、第１セッターとセラミックグリーンシートとが互いに接触するように積層された積層体を焼成し、セラミックグリーンシートとの接触面に第１セッターの含有成分とは異なる成分を含む異物が付着した第２セッターを得る焼成工程（第１焼成工程）と、上記積層体を第２セッターとセラミック板とに分別し、上記接触面の少なくとも一部が露出した状態で第２セッターを加熱して、上記接触面における異物を低減する加熱工程と、を有する。 In the method for manufacturing a setter (regeneration method) according to an embodiment, a laminated body in which the first setter and the ceramic green sheet are laminated so as to be in contact with each other is fired, and the contact surface of the first setter is formed on the contact surface with the ceramic green sheet. A firing step (first firing step) for obtaining a second setter to which a foreign substance containing a component different from the contained component is attached, and the laminate is separated into a second setter and a ceramic plate, and at least a part of the contact surface is formed. It has a heating step of heating the second setter in an exposed state to reduce foreign matters on the contact surface.
　焼成工程は、上述の第１焼成工程と同様にして行うことができる。すなわち、第１セッターは、市販のセラミック焼結体を購入してもよいし、公知の方法で製造してもよい。セッターは、例えば、窒化ホウ素、炭化ケイ素、アルミナ、ジルコニア、グラファイト、及び窒化ケイ素からなる群より選ばれる少なくとも一種で構成されるものが挙げられる。第１セッターとして窒化ホウ素焼結体を用いる場合の製造手順は、上述したとおりであってよい。焼成工程は、図１に示すような積層体を焼成炉２５に収容して加熱してよい。本実施形態では、焼成工程（第１焼成工程）で焼成される前のセッターを「第１セッター」、焼成工程で焼成されて接触面に異物が付着したセッターを「第２セッター」と称している。 The firing step can be performed in the same manner as the first firing step described above. That is, the first setter may be a commercially available ceramic sintered body or may be manufactured by a known method. Examples of the setter include those composed of at least one selected from the group consisting of boron nitride, silicon carbide, alumina, zirconia, graphite, and silicon nitride. The manufacturing procedure when the boron nitride sintered body is used as the first setter may be as described above. In the firing step, the laminate as shown in FIG. 1 may be housed in the firing furnace 25 and heated. In the present embodiment, the setter before firing in the firing step (first firing step) is referred to as a "first setter", and the setter baked in the firing step and having foreign matter adhered to the contact surface is referred to as a "second setter". There is.
　加熱工程では、焼成工程で得られた積層体を、セラミック板と第２セッターに分別し、第２セッターのセラミックグリーンシート（セラミック板）との接触面の少なくとも一部が露出した状態で第２セッターを加熱する。これによって、接触面に付着していた異物が揮発又は分解し、異物を低減することができる。このように加熱工程によって異物が低減されたセッターを「第３セッター」と称する場合もある。 In the heating step, the laminate obtained in the firing step is separated into a ceramic plate and a second setter, and the second setter is in a state where at least a part of the contact surface with the ceramic green sheet (ceramic plate) of the second setter is exposed. Heat the setter. As a result, the foreign matter adhering to the contact surface is volatilized or decomposed, and the foreign matter can be reduced. A setter in which foreign matter is reduced by the heating step in this way may be referred to as a "third setter".
　加熱工程における加熱条件は、上述のセラミック板の製造方法の実施形態における加熱工程と同じであってよい。加熱工程によって得られるセッター（第３セッター）の表面に付着する異物は十分に低減されている。このセッター（第３セッター）は、例えば、第１セッターと同等の表面品質を有していてよい。このように加熱工程を経て得られるセッター（第３セッター）を、第１セッターに代えて焼成工程（第２焼成工程）で用いてもよい。これによって、セラミック板とともに、接触面に異物が付着した第２セッターが再び得られる。この後、再び加熱工程を行ってよい。 The heating conditions in the heating step may be the same as the heating step in the embodiment of the method for manufacturing a ceramic plate described above. Foreign matter adhering to the surface of the setter (third setter) obtained by the heating step is sufficiently reduced. This setter (third setter) may have, for example, the same surface quality as the first setter. The setter (third setter) thus obtained through the heating step may be used in the firing step (second firing step) instead of the first setter. As a result, the second setter in which the foreign matter adheres to the contact surface is obtained again together with the ceramic plate. After this, the heating step may be performed again.
　このように、本実施形態のセッターの製造方法（再生方法）によれば、使用済みの第２セッターを第３セッターとして再生し、第２セッターの廃棄量を低減することができる。これによって、資源の有効利用を図ることができる。第２焼成工程と加熱工程は、複数回繰り返して行ってよい。この場合、第２セッターから第３セッターの再生と、第３セッター用いたセラミック板の生産（第２セッターの生成）と、が繰り返し行われることとなる。したがって、資源の有効利用を一層図ることができる。 As described above, according to the setter manufacturing method (regeneration method) of the present embodiment, the used second setter can be regenerated as the third setter, and the amount of waste of the second setter can be reduced. This makes it possible to make effective use of resources. The second firing step and the heating step may be repeated a plurality of times. In this case, the reproduction of the second setter to the third setter and the production of the ceramic plate using the third setter (generation of the second setter) are repeatedly performed. Therefore, effective use of resources can be further promoted.
　なお、本実施形態のセッターの製造方法は、焼成工程で使用された使用済みの第２セッターを加熱し、表面における異物が低減されたセッター（第３セッター）を新しく作り出している点で、セッターの製造方法に該当する。別の観点からすると、使用済みのセッターの表面処理を行って、使用済みのセッターを再生していることから、セッターの表面処理方法、又は、セッターの再生方法ということもできる。 The setter manufacturing method of the present embodiment heats the used second setter used in the firing step to newly create a setter (third setter) in which foreign matter on the surface is reduced. Corresponds to the manufacturing method of. From another point of view, since the used setter is surface-treated and the used setter is regenerated, it can be said that the setter is surface-treated or the setter is regenerated.
　以上、本開示の一実施形態について説明したが、本開示は上記実施形態に何ら限定されるものではない。例えば、セラミック板、セラミックグリーンシート及びセッターは、直方体形状以外の形状を有していてもよい。これらは角部において面取りが施されていてもよい。また、セッターは、積層体の下方にのみ配置されてもよい。 Although the embodiment of the present disclosure has been described above, the present disclosure is not limited to the above embodiment. For example, the ceramic plate, the ceramic green sheet, and the setter may have a shape other than the rectangular parallelepiped shape. These may be chamfered at the corners. Further, the setter may be arranged only below the laminated body.
［セラミック板の製造及びセッターの再生］
（実施例１）
＜第１焼成工程＞
　窒化ケイ素粉末と焼結助剤（酸化マグネシウム粉末、酸化イットリウム粉末及び二酸化ケイ素粉末）を含む原料粉末を一軸加圧成形して成形体（シート材）を作製した。このシート材を、切断装置を用いて打ち抜いて、直方体形状を有する６８枚のセラミックグリーンシートを形成した。これとは別に、直方体形状を有する窒化ホウ素製のセッター（デンカ株式会社製、商品名：ＮＢ－１０００）を３枚準備した。図４は、セッターの主面（焼成前）のＳＥＭ写真（１００倍）である。図５は、図４よりも高い倍率で撮影したセッターの主面（焼成前）のＳＥＭ写真（５００倍）である。図４及び図５に示すように、焼成前のセッター（第１セッター）の主面には異物は検出されなかった。以下では、この主面とセラミックグリーンシートとが接触するようにして積層体を作製した。 [Manufacturing of ceramic plates and regeneration of setters]
(Example 1)
<First firing step>
A molded body (sheet material) was prepared by uniaxial pressure molding of a raw material powder containing silicon nitride powder and a sintering aid (magnesium oxide powder, yttrium oxide powder and silicon dioxide powder). This sheet material was punched out using a cutting device to form 68 ceramic green sheets having a rectangular parallelepiped shape. Separately, three setters made of boron nitride having a rectangular parallelepiped shape (manufactured by Denka Co., Ltd., trade name: NB-1000) were prepared. FIG. 4 is an SEM photograph (100 times) of the main surface (before firing) of the setter. FIG. 5 is an SEM photograph (500 times) of the main surface (before firing) of the setter taken at a higher magnification than that of FIG. As shown in FIGS. 4 and 5, no foreign matter was detected on the main surface of the setter (first setter) before firing. In the following, a laminate was produced so that the main surface and the ceramic green sheet were in contact with each other.
　６８枚のセラミックグリーンシートを一対のセッターで上下に挟むとともに、中央部にセッターを配置して、３枚のセッター（３枚の第１セッター）と６８枚のセラミックグリーンシートが積層された積層体を得た。この積層体では、下側のセッターと中央部のセッターとの間、及び中央部のセッターと上側のセッターとの間のそれぞれに、３４枚のセラミックグリーンシートが積み重ねられていた。積層体を作製するにあたり、セラミックグリーンシートとのセッターの接触面、及び、各セラミックグリーンシートの一方の主面には、離型用のスラリーを塗布した。脱脂炉及び焼成炉を用い、作製した積層体の脱脂及び焼成を行った。脱脂温度は５００℃、脱脂時間は３０時間とした。また、焼成温度は１８００℃、焼成時間は３０時間とした。焼成後、焼成炉から積層体を取り出し、積層体からセラミック板を取り除いて一対のセッターを回収した。 A laminated body in which 68 ceramic green sheets are sandwiched vertically with a pair of setters, and a setter is arranged in the center, and 3 setters (3 first setters) and 68 ceramic green sheets are laminated. Got In this laminated body, 34 ceramic green sheets were stacked between the lower setter and the central setter, and between the central setter and the upper setter. In producing the laminate, a slurry for mold release was applied to the contact surface of the setter with the ceramic green sheet and one main surface of each ceramic green sheet. Using a degreasing furnace and a firing furnace, the prepared laminate was degreased and fired. The degreasing temperature was 500 ° C. and the degreasing time was 30 hours. The firing temperature was 1800 ° C. and the firing time was 30 hours. After firing, the laminate was taken out from the firing furnace, the ceramic plate was removed from the laminate, and a pair of setters were recovered.
　セラミックグリーンシートとのセッターの接触面（セラミックグリーンシートと対向していた主面）を、走査型電子顕微鏡（ＳＥＭ）で観察した。図６は、積層体から回収されたセッターの接触面のＳＥＭ写真（１００倍）である。図７は、図６よりも高い倍率で撮影したセッターの接触面のＳＥＭ写真（５００倍）である。目視では、異物の存在が確認できなかったものの、図７に示すようにＳＥＭを用いて接触面を高倍率（約５００倍）で観察すると、異物４０が付着していることが確認された。この異物のＥＤＳ分析を行ったところ、ＳｉとＮが検出された。このことから、セッターの接触面には、セラミックグリーンシート（セラミック板）の含有成分である窒化ケイ素粒子が異物として存在していたことが確認された。 The contact surface of the setter with the ceramic green sheet (the main surface facing the ceramic green sheet) was observed with a scanning electron microscope (SEM). FIG. 6 is an SEM photograph (100 times) of the contact surface of the setter recovered from the laminated body. FIG. 7 is an SEM photograph (500 times) of the contact surface of the setter taken at a higher magnification than that of FIG. Although the presence of foreign matter could not be confirmed visually, when the contact surface was observed at a high magnification (about 500 times) using an SEM as shown in FIG. 7, it was confirmed that the foreign matter 40 had adhered. When EDS analysis of this foreign substance was performed, Si and N were detected. From this, it was confirmed that the silicon nitride particles, which are the components contained in the ceramic green sheet (ceramic plate), were present as foreign substances on the contact surface of the setter.
＜加熱工程＞
　接触面に異物が付着していることが確認された３枚のセッター（３枚の第２セッター）を、図３に示すように、スペーサを介して積み重ねて、焼成炉内に配置した。接触面のうち異物が付着した部分は、スペーサと接触せずに焼成炉内の空間に露出するようにした。焼成炉を用いて、窒素ガス雰囲気中において３枚のセッターを１８５０℃で２時間加熱した。 <Heating process>
As shown in FIG. 3, three setters (three second setters) confirmed to have foreign matter attached to the contact surface were stacked via spacers and placed in the firing furnace. The portion of the contact surface to which foreign matter adhered was exposed to the space inside the firing furnace without contacting the spacer. Using a calcining furnace, three setters were heated at 1850 ° C. for 2 hours in a nitrogen gas atmosphere.
　図８は、加熱工程で加熱した後のセッターの接触面のＳＥＭ写真（１００倍）である。図９は、図８よりも高い倍率で撮影したセッターの接触面のＳＥＭ写真（５００倍）である。図９は図７と同じ倍率で拡大されたセッターの接触面を示している。図９に示すとおり、加熱工程によって、接触面に付着していた異物が十分に低減されていた。 FIG. 8 is an SEM photograph (100 times) of the contact surface of the setter after heating in the heating step. FIG. 9 is an SEM photograph (500 times) of the contact surface of the setter taken at a higher magnification than that of FIG. FIG. 9 shows the contact surface of the setter magnified at the same magnification as in FIG. As shown in FIG. 9, the heating process sufficiently reduced the foreign matter adhering to the contact surface.
（比較例１）
　実施例１と同様にして焼成工程を行い、接触面に異物が付着する３枚のセッター（３枚の第２セッター）を得た。３枚のセッターの接触面同士が接触するように積み重ねて焼成炉で加熱したこと以外は、実施例１と同様にして加熱工程を行った。すなわち、３枚のセッターの接触面が焼成炉内の空間に露出しないようにして３枚のセッターを焼成した。 (Comparative Example 1)
The firing step was carried out in the same manner as in Example 1 to obtain three setters (three second setters) to which foreign matter adhered to the contact surface. The heating step was performed in the same manner as in Example 1 except that the contact surfaces of the three setters were stacked so as to be in contact with each other and heated in the firing furnace. That is, the three setters were fired so that the contact surfaces of the three setters were not exposed to the space inside the firing furnace.
　図１０は、加熱工程で加熱した後のセッターの接触面のＳＥＭ写真（１００倍）である。図１１は、図１０よりも高い倍率で撮影したセッターの接触面のＳＥＭ写真（５００倍）である。図１０及び図１１に示すとおり、セッターの接触面には、加熱工程で粒成長して粗大化した異物４２が存在していた。 FIG. 10 is an SEM photograph (100 times) of the contact surface of the setter after heating in the heating step. FIG. 11 is an SEM photograph (500 times) of the contact surface of the setter taken at a higher magnification than that of FIG. As shown in FIGS. 10 and 11, foreign matter 42 that had grown and coarsened in the heating step was present on the contact surface of the setter.
［セッターの再利用及びセラミック板の評価］
（実施例１及び比較例１）
＜第２焼成工程＞
　実施例１及び比較例１の上記加熱工程で得られたセッター（第３セッター）をそれぞれ用いて、第２焼成工程を行った。第２焼成工程の積層体の作製手順及び焼成条件は、上記第１焼成工程と同様にした。第２焼成工程で得られた各セラミック板（窒化ケイ素板）の表面における凹凸の有無を評価した。図１２は、第２焼成工程で得られた窒化ケイ素板の表面における凸部の例を示す写真である。図１２では、窒化ケイ素板の主面の中央部に形成された凸部６０が示されている。 [Reuse of setters and evaluation of ceramic plates]
(Example 1 and Comparative Example 1)
<Second firing step>
The second firing step was performed using the setters (third setters) obtained in the heating steps of Example 1 and Comparative Example 1, respectively. The procedure for producing the laminate and the firing conditions in the second firing step were the same as those in the first firing step. The presence or absence of unevenness on the surface of each ceramic plate (silicon nitride plate) obtained in the second firing step was evaluated. FIG. 12 is a photograph showing an example of a convex portion on the surface of the silicon nitride plate obtained in the second firing step. In FIG. 12, a convex portion 60 formed in the central portion of the main surface of the silicon nitride plate is shown.
　実施例１及び比較例１の第２焼成工程で得られた各窒化ケイ素板の品質評価を行った。具体的には、窒化ケイ素板の主面を、株式会社キーエンス製のワンショット３Ｄ形状測定機（型式：ＶＲ－３０００）で観察し、表面の凹凸のサイズを調べた。高さ１１μｍ以上の凸部、又は深さ１１μｍ以上の凹部がある場合を不良品と判定した。その結果、比較例１に対して実施例１では、不良品の比率を１／３以下に低減することができた。 The quality of each silicon nitride plate obtained in the second firing step of Example 1 and Comparative Example 1 was evaluated. Specifically, the main surface of the silicon nitride plate was observed with a one-shot 3D shape measuring machine (model: VR-3000) manufactured by KEYENCE CORPORATION, and the size of the unevenness on the surface was examined. A defective product was determined to have a convex portion having a height of 11 μm or more or a concave portion having a depth of 11 μm or more. As a result, in Example 1, the ratio of defective products could be reduced to 1/3 or less as compared with Comparative Example 1.
　本開示によれば、セッターを再生することによって、セラミック板の生産効率を向上することが可能なセラミック板の製造方法を提供することができる。また、資源を有効活用することが可能なセッターの製造方法を提供することができる。 According to the present disclosure, it is possible to provide a method for manufacturing a ceramic plate capable of improving the production efficiency of the ceramic plate by regenerating the setter. In addition, it is possible to provide a method for manufacturing a setter that can effectively utilize resources.
　１０，１０Ａ，１０Ｂ，１０Ｃ，１１…セッター，１２…スペーサ，１３…底板，２０…脱脂炉，２５…焼成炉，２８…加熱炉，３０…セラミックグリーンシート、３０ａ…第１セラミックグリーンシート、４０，４２…異物，５０…積層体，６０…凸部。

  10, 10A, 10B, 10C, 11 ... setter, 12 ... spacer, 13 ... bottom plate, 20 ... degreasing furnace, 25 ... firing furnace, 28 ... heating furnace, 30 ... ceramic green sheet, 30a ... first ceramic green sheet, 40 , 42 ... foreign matter, 50 ... laminated body, 60 ... convex part.

Claims (9)

  1. 　セッターと第１セラミックグリーンシートとが互いに接触するように積層して焼成しセラミック板を得る第１焼成工程と、
    　前記第１セラミックグリーンシートとの前記セッターの接触面の少なくとも一部が露出した状態で前記セッターを加熱する加熱工程と、
    　前記セッターと第２セラミックグリーンシートとが前記接触面の少なくとも一部において互いに接触するように積層して焼成しセラミック板を得る第２焼成工程と、を有する、セラミック板の製造方法。     The first firing step of laminating and firing the setter and the first ceramic green sheet so as to be in contact with each other to obtain a ceramic plate, and
    A heating step of heating the setter with at least a part of the contact surface of the setter with the first ceramic green sheet exposed.
    A method for manufacturing a ceramic plate, comprising a second firing step of laminating and firing the setter and a second ceramic green sheet so as to be in contact with each other at at least a part of the contact surface to obtain a ceramic plate.
  2. 　前記加熱工程では、前記接触面に付着する、前記セッターの含有成分とは異なる成分を含む異物が分解する温度以上に加熱する、請求項１に記載のセラミック板の製造方法。 The method for manufacturing a ceramic plate according to claim 1, wherein in the heating step, the ceramic plate is heated to a temperature higher than a temperature at which a foreign substance containing a component different from the component contained in the setter that adheres to the contact surface is decomposed.
  3. 　前記第１焼成工程では、複数のセッターと複数の第１セラミックグリーンシートとがそれぞれ接触するように積層して焼成し、
    　前記加熱工程では、前記複数のセッターの、前記第１セラミックグリーンシートと接触していた接触面同士を互いに離した状態で前記複数のセッターを加熱する、請求項１又は２に記載のセラミック板の製造方法。     In the first firing step, the plurality of setters and the plurality of first ceramic green sheets are laminated and fired so as to be in contact with each other.
    The ceramic plate according to claim 1 or 2, wherein in the heating step, the plurality of setters are heated in a state where the contact surfaces of the plurality of setters that have been in contact with the first ceramic green sheet are separated from each other. Production method.
  4. 　前記第１セラミックグリーンシートは窒化ケイ素を含み、
    　前記加熱工程では、不活性ガス雰囲気中で前記セッターを１４５０～２０００℃で加熱する、請求項１～３のいずれか一項に記載のセラミック板の製造方法。     The first ceramic green sheet contains silicon nitride and contains
    The method for producing a ceramic plate according to any one of claims 1 to 3, wherein in the heating step, the setter is heated at 1450 to 2000 ° C. in an atmosphere of an inert gas.
  5. 　第１セッターとセラミックグリーンシートとが互いに接触するように積層して焼成し、前記セラミックグリーンシートとの接触面に前記第１セッターの含有成分とは異なる成分を含む異物が付着した第２セッターを得る焼成工程と、
    　前記接触面の少なくとも一部が露出した状態で前記第２セッターを加熱して、前記接触面における前記異物を低減する加熱工程と、を有する、セッターの製造方法。     The first setter and the ceramic green sheet are laminated and fired so as to be in contact with each other, and the second setter to which a foreign substance containing a component different from the component contained in the first setter is attached to the contact surface with the ceramic green sheet is attached. The firing process to obtain and
    A method for manufacturing a setter, comprising a heating step of heating the second setter with at least a part of the contact surface exposed to reduce the foreign matter on the contact surface.
  6. 　前記加熱工程では、前記異物が分解する温度以上に加熱する、請求項５に記載のセッターの製造方法。 The method for manufacturing a setter according to claim 5, wherein in the heating step, the setter is heated to a temperature higher than the temperature at which the foreign matter is decomposed.
  7. 　前記焼成工程では、複数の第１セッターと、複数のセラミックグリーンシートとがそれぞれ接触するように積層して焼成し複数の第２セッターを得て、
    　前記加熱工程では、前記複数の第２セッターの、前記セラミックグリーンシートと接触していた接触面同士を互いに離した状態で前記複数の第２セッターを加熱する、請求項５又は６に記載のセッターの製造方法。     In the firing step, the plurality of first setters and the plurality of ceramic green sheets are laminated and fired so as to be in contact with each other to obtain a plurality of second setters.
    The setter according to claim 5 or 6, wherein in the heating step, the plurality of second setters are heated in a state where the contact surfaces of the plurality of second setters that have been in contact with the ceramic green sheet are separated from each other. Manufacturing method.
  8. 　前記セラミックグリーンシートは窒化ケイ素を含み、
    　前記加熱工程では、不活性ガス雰囲気中で前記第２セッターを１４５０～２０００℃で加熱する、請求項５～７のいずれか一項に記載のセッターの製造方法。     The ceramic green sheet contains silicon nitride and contains
    The method for producing a setter according to any one of claims 5 to 7, wherein in the heating step, the second setter is heated at 1450 to 2000 ° C. in an atmosphere of an inert gas.
  9. 　第１セッターとセラミックグリーンシートとが互いに接触するように積層して焼成し、前記セラミックグリーンシートとの接触面に前記第１セッターの含有成分とは異なる成分を含む異物が付着した第２セッターを得る焼成工程と、
    　前記接触面の少なくとも一部が露出した状態で前記第２セッターを加熱して、前記接触面における前記異物を低減する加熱工程と、を有する、セッターの再生方法。

          The first setter and the ceramic green sheet are laminated and fired so as to be in contact with each other, and the second setter to which a foreign substance containing a component different from the component contained in the first setter is attached to the contact surface with the ceramic green sheet is attached. The firing process to obtain and
    A method for regenerating a setter, comprising a heating step of heating the second setter with at least a part of the contact surface exposed to reduce the foreign matter on the contact surface.
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