JP4870401B2 - Manufacturing method of ceramic structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a ceramic structure having a recess or void with high dimensional accuracy. <P>SOLUTION: In manufacturing the ceramic structure E having at least either of the surface recess 7 and the internal void 10 by laminating a plurality of ceramic green sheets, followed by baking, the manufacturing method comprises a step of laying, on the vacancy part that has a volume V and which forms the recess 7 of the ceramic green sheet and on the vacancy part which forms the void 10, a resin sheet 2a having an occupying volume of 0.8-1.1V (the occupying volume includes the volume of the air bubbles contained in the inside of the resin sheet), a step of laminating a plurality of the above ceramic green sheets, and a step of pyrolizing and removing the resin sheet 2a upon baking the laminated body of the ceramic green sheets. The resin sheet 2a contains air bubbles, and the volume V<SB>liq.</SB>of the resin sheet 2a in the molten state immediately before thermal decomposition is 0.2-0.6V. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  The present invention relates to a method for manufacturing a ceramic structure formed by laminating a plurality of ceramic green sheets, integrating them, and firing, and in particular, manufacturing a ceramic structure having a concave portion on the surface and a ceramic structure having a hollow structure inside. Regarding the method.

  Conventionally, applications of a ceramic structure having a recess on the surface include, for example, electronic component storage packages for storing semiconductor elements such as LSI and various electronic components, and flow paths for various fluids. A three-dimensional structure in which a concave structure for mounting semiconductor elements, sensors, various electronic components, etc., or various fluid flow paths, etc. are formed on multiple surfaces in order to achieve both high functionality and high functionality and small size and low profile. There is a growing demand for a ceramic structure having a complicated shape. Furthermore, there is also a demand for a ceramic structure having a complicated shape in which a cavity for mounting a semiconductor element, a sensor, various electronic components, and the like or a cavity for forming various fluid flow paths is formed.

  These are being applied to fields such as microchemical chips, μ-TAS (Micro Total Analysis System), and MEMS (Micro Electro Mechanical Systems). These are performed by finely processing silicon, glass or the like using a semiconductor fine processing technique or the like.

  In particular, fine devices that integrate a composite function such as mechanical, electronic, optical, chemical, biochemical, etc. are being actively developed because they are superior in performance and energy saving (for example, Patent Document 1). In these integration technologies, a technology for forming a concave structure such as a metallized wiring or a flow path on the same substrate and a technology for stacking a plurality of substrates are important. These techniques are generally performed in a method of manufacturing a ceramic structure such as a ceramic multilayer wiring board or a ceramic multilayer electronic component, and applications of these conventional techniques are expected. Ceramic is also a promising material because of its excellent chemical resistance, recyclability, and easy chemical cleaning.

  As a method for manufacturing a ceramic structure, for example, in the case of a ceramic structure in which a metallized wiring layer is disposed on the surface or inside of an insulator in which a plurality of insulating layers are stacked, first, a ceramic raw material powder prepared at a predetermined ratio is used. A suitable resin binder is added and a slurry is prepared by dispersing in an organic solvent, and a ceramic green sheet having a predetermined thickness (hereinafter, also referred to as a green sheet) by a known casting method such as a doctor blade method or a lip coater method. ).

  Next, as a metallized wiring layer, a metal paste obtained by adding and mixing a resin binder, a solvent, and a plasticizer to an appropriate metal powder is printed and applied to the above green sheet in a predetermined pattern by a well-known screen printing method. At the same time, a through hole (through hole) is formed by a micro drill or a laser, and a metal paste is filled in the through hole to form a through conductor (via conductor, via hole).

Subsequent steps will be described separately for (I) a ceramic structure having a recess on the surface and (II) a ceramic structure having a cavity inside.
In the case of (I), in order to form a concave portion on the surface, a through hole is formed by punching in a predetermined portion of the green sheet. After that, by laminating a plurality of green sheets with the above-mentioned through holes together with other green sheets using an appropriate adhesion liquid, and firing the green sheet laminate including the obtained recesses under predetermined conditions, A ceramic structure having a recess on the surface is obtained.

  In the case of (II), a ceramic structure having a cavity can be obtained by laminating a plurality of green sheet laminates having recesses produced by the same method as in (I) above and firing them under predetermined conditions. .

  In recent years, in order to achieve both multi-function / high functionality and small size / low profile in such ceramic structures, the ceramic structures have been three-dimensionally structured. It is indispensable to prevent the sheet from being deformed. Furthermore, it is desired to deal with a complex ceramic structure having a plurality of concave portions or cavities with high dimensional accuracy, which is formed from a sintered surface having high flatness after firing.

  However, when a ceramic structure having a recess or a cavity is pressed and laminated with a green sheet in which a through-hole constituting the recess or cavity is formed and a green sheet in which no through-hole is formed, When a pressure difference occurs between the other parts, the bottom of the recess or cavity of the green sheet laminate that is not subjected to pressure swells.Therefore, bonding defects occur when electronic parts are mounted on the bottom of the recess or cavity. In the case of induction or in the case of a flow path, since the deviation of the cross-sectional area becomes large, precise flow rate adjustment may not be possible.

  In addition, if the pressure is reduced to solve the above problem, the pressure necessary for the close contact of the recesses or the periphery of the cavity is reduced, causing delamination between the green sheets. It was difficult to obtain a highly reliable ceramic structure without the above.

  In addition, when the side wall surrounding the recess or cavity is thin and weak, there is a problem that the thin side wall is deformed at the time of pressurization such as lamination, or a plurality of recesses or cavities are narrowed by punching into the same green sheet When forming at intervals, or when cutting (cutting) each piece of ceramic structure by cutting with a metal blade etc. between multiple recesses or cavities formed in the same green sheet At the time of so-called raw processing, a problem that the side wall having a thin concave portion or cavity is deformed easily occurs.

  Therefore, as a technique for solving these problems, pressure equalization lamination is performed with a filler such as a non-sintered powder, a sublimable substance, a resin, and a wax inserted in a portion where a recess or a cavity is formed, and then the filler is A removal method is disclosed (for example, Patent Documents 1 to 3). According to these methods, pressure equalization lamination is possible, so that it is possible to obtain a ceramic molded body having a recess or a cavity excellent in flatness and dimensional accuracy.

  However, in the case of an unsintered powder filling, a process for removing the unsintered packing after firing is necessary, and it has not been applicable to a ceramic structure having a cavity inside. Further, when removal of unsintered powder or the like is insufficient, there is a risk of causing various problems such as insulation failure. On the other hand, in the case of a filler such as a sublimable substance, resin, wax, etc., when the filler is removed by sublimation, evaporation, melting, thermal decomposition, etc. after the pressure lamination process, the decomposition product comes into contact with it. There are problems that chemically and physically act on the resin binder and ceramics contained in the green sheet, causing resin binder dissolution, ceramic surface alteration, and deformation and cracking of the green sheet due to the pressure of the generated decomposition gas. It was.

  These problems are particularly noticeable when the amount of filling material to be fitted is large. That is, in the process of removing the packing, since the packing starts thermal decomposition all at once, a large amount of melt, gas, etc. is generated, which is considered to increase the damage to the green sheet in contact with it. It is done.

  On the other hand, Patent Document 4 includes resin beads that are thermally decomposed at a predetermined temperature, and is fitted into a recess of the ceramic green sheet laminate, and is thermally decomposed by sintering the laminate, and the recess is formed in the sintered body. A resin sheet to be formed is described. According to this document, it is described that when the resin sheet is used, pressure equalization lamination becomes possible, delamination and deformation of the concave portion can be prevented, and generation of delamination can be suppressed.

  However, since the resin beads contained for imparting the punching processability to the resin sheet generate a melt or gas at the time of binder removal, the resin sheet described in Patent Document 4 can be used. However, the present situation is that a ceramic structure with high dimensional accuracy is not necessarily obtained.

JP 2001-358247 A Japanese Patent Laid-Open No. 10-249838 JP-A-8-245268 JP 2004-356347 A “Technical Survey Report (Technology Trends) No. 3 Current Status and Issues of MEMS-related Technologies”, March 28, 2003, Ministry of Economy, Trade and Industry

  Accordingly, the present invention has been completed in view of the above problems, and its object is to provide a ceramic structure having a concave portion on the surface and a cavity formed inside by laminating and firing a plurality of ceramic green sheets. In particular, a method for producing a ceramic structure having a structure, in which a resin sheet is thermally decomposed when the resin sheet is thermally decomposed and removed by filling the resin sheet into a concave portion and a hollow portion and pressure-equalizing lamination. It is to provide a method for manufacturing a ceramic structure having a recess or a cavity with high dimensional accuracy by adjusting the volume of.

As a result of intensive studies to solve the above problems, the present inventor has found a solution means having the following configuration, and has completed the present invention.
(1) When a ceramic structure having at least one of a concave portion on the surface and an internal cavity is manufactured by laminating and firing a plurality of ceramic green sheets, a void serving as the concave portion of the ceramic green sheet having a volume V A step of placing a resin sheet (occupied volume includes a volume of bubbles contained in the resin sheet) on the portion and the void portion serving as the cavity, and the ceramic green sheet A step of laminating a plurality of sheets, and a step of thermally decomposing and removing the resin sheet when firing the ceramic green sheet laminate, wherein the resin sheet contains bubbles and the resin sheet is thermally decomposed. In addition to satisfying the relationship that the immediately preceding molten state volume V _liq. Is 0.2 V to 0.6 V , the average diameter of the bubbles is 25 μm. The method for producing a ceramic structure according to claim 1 , wherein the resin sheet further includes a resin binder, and the resin binder is isobutyl methacrylate .
(2) The method for producing a ceramic structure according to (1), wherein the resin sheet is thermally decomposed at 99% by weight or more at 600 ° C.
(3) The resin sheet, the comprising at least one of the variable plasticizer and lubricants (1) or (2) method for producing a ceramic structure according.
(4) The ceramic structure according to any one of (1) to (3), wherein an average diameter of the bubbles contained in the resin sheet is equal to or less than (1/3) t with respect to a thickness t of the resin sheet. Manufacturing method.
(5) The method for producing a ceramic structure according to any one of (1) to (4), wherein the resin sheet includes resin beads.
(6) In the step of placing the resin sheet in the void portion that becomes the concave portion and the void portion that becomes the cavity of the ceramic green sheet, a step of forming a through hole constituting the concave portion or the cavity in the ceramic green sheet; The resin sheet is fitted into the hole to form a resin sheet-green sheet composite, and the process of laminating a plurality of the resin sheets-green sheet composite is any one of the above (1) to (5). A method for producing a ceramic structure.
(7) wherein in the step of removing by thermal decomposition of the resin sheet at the time of firing the laminate of the ceramic green sheet, the 80% weight loss temperature of the upper portion of the resin sheet T _a ° C., the lowermost resin sheet When the 80% weight reduction temperature of the part is T _b ° C and the 20% weight reduction temperature of the resin binder contained in the green sheet on which the resin sheet is placed is T _c ° C, T _a <T _b ≦ T _c The manufacturing method of the ceramic structure in any one of said (1)-(6) which satisfy | fills a relationship.
(8) A first debinding step in which the upper layer portion of the resin sheet is thermally decomposed and removed at the T _a ° C, and then a second debinding step in which the lowermost layer portion of the resin sheet is thermally decomposed and removed at the T _b ° C. And a third debinding step of thermally decomposing and removing the resin binder contained in the green sheet at a temperature exceeding _Tc ° C., and the method for producing a ceramic structure according to (7).

According to the above (1), when a ceramic structure having at least one of a concave portion on the surface and an internal cavity is manufactured by laminating and firing a plurality of ceramic green sheets, the concave portion of the ceramic green sheet having a volume V is produced. A step of producing a resin sheet-ceramic green sheet composite by placing a resin sheet at a predetermined occupied volume in a void portion to become a void portion and a resin sheet-ceramic by laminating a plurality of ceramic green sheets Since it includes a step of producing a laminate including at least one green sheet composite and a step of thermally decomposing and removing the resin sheet when the obtained ceramic green sheet laminate is fired, pressure equalization lamination is possible. Therefore, it is possible to form a ceramic structure with no deformation in the recesses and cavities and no delamination. To become. In addition, since a thermally decomposable resin sheet is used, the laminated body may be fired at once without removing the resin sheet filled in the recesses or cavities, and the number of processes can be reduced. Furthermore, since the volume V _{liq. Of} the molten state immediately before the resin sheet is thermally decomposed satisfies a predetermined relationship, the amount of the thermally decomposed product can be reduced, so that the resin binder, ceramics, etc. contained in the green sheet in contact with it can be chemically treated. It is possible to reduce the deformation and cracking of the green sheet due to the pressure of the dissolved gas, the dissolution of the resin binder, the surface modification of the ceramic, and the generated decomposition gas. In addition, since the resin sheet contains bubbles, when shearing such as punching or cutting of the resin sheet, cracks are easily generated in the shearing direction through the bubbles, and thus shearing can be easily performed. Since the propagation of cracks other than the above is suppressed by the presence of bubbles, the crack propagation to the direction other than the shear direction can be suppressed and shear processing can be performed to a desired shape, so that a resin sheet having substantially the same shape as the through hole can be fitted. Become. Furthermore, since the amount of the thermal decomposition product of the resin sheet at the time of firing can be reduced also by adjusting the content of bubbles contained in the resin sheet, it is possible to reduce the various problems described above with respect to the green sheet in contact therewith.

According to the above (2), since the resin sheet according to the method of the present invention is thermally decomposed by 99% by weight or more at 600 ° C., the resin sheet pyrolysis residue (carbon) is present on the contact surface with the resin sheet during firing. Residuality can be prevented more effectively, and induction of electrical failure can be suppressed.
According to the above (3), the resin sheet according to the present process, because they contain at least one of the variable plasticizer and a lubricant, by changing these formulations compositions, the strength of the ceramic green sheet to be used, elongation, etc. The physical properties of the resin sheet can be adjusted according to the mechanical properties. In other words, it is possible to impart flexibility or flexibility to the resin sheet by at least hand plasticizers and lubricants, it is possible to further improve the workability.
According to the above (4), since the average diameter of the bubbles contained in the resin sheet according to the method of the present invention is (1/3) t or less with respect to the thickness t of the resin sheet, the resin sheet can be finely processed. Become. Therefore, it is possible to form a void portion that becomes a concave portion or a void portion that becomes a cavity of the ceramic green sheet having a fine and complicated shape. Moreover, since the rigidity of the resin sheet itself can be maintained, even pressure lamination can be maintained even when laminated at a high pressure.
According to the above (5), since the resin sheet according to the method of the present invention contains resin beads in addition to bubbles, the shearing workability of the resin sheet is further improved and the resin beads are rigid. Thus, even when the layers are laminated at a high pressure, the pressure equalizing laminate property can be further improved.
According to the above (6) to (8), since the resin sheet can be thermally decomposed in order from the upper layer portion to the lowermost layer portion, a ceramic structure having a recess or a cavity with high dimensional accuracy can be obtained with certainty. .

  The method for producing a ceramic structure of the present invention will be described in detail below. The method of the present invention produces a ceramic structure having at least one of a concave portion on the surface and an internal cavity by laminating and firing a plurality of ceramic green sheets.

<Green sheet>
The green sheet for producing the ceramic structure can be produced as follows. First, if necessary, a ceramic powder serving as a sintering aid is added to at least one of the raw material powder of the green sheet, for example, ceramic powder and glass powder. A slurry is prepared by adding a solvent or the like. Thereafter, a green sheet having a predetermined thickness is formed using the slurry by a forming method such as a doctor blade method, a rolling method, or a pressing method.

  Next, when forming an electrical wiring or the like, by punching the green sheet, a through hole serving as a via hole connecting the upper and lower wiring conductor layers is formed, and the conductor paste is placed in the through hole. Fill.

  Ceramic powders include metal or non-metal oxides or non-oxide powders. These powders may be used in a single composition or in the form of a compound alone or in combination. Specifically, Li, K, Mg, B, Al, Si, Cu, Ca, Br, Ba, Zn, Cd, Ga, In, lanthanoid, actinoid, Ti, Zr, Hf, Bi, V, Nb, Ta , W, Mn, Fe, Co, Ni, and other oxides, carbides, nitrides, borides, sulfides, and the like.

More specifically, a composite oxide of SiO ₂ , Al ₂ O ₃ , ZrO ₂ , TiO ₂ and an alkaline earth metal oxide, ZnO, MgO, MgAl ₂ O ₄ , ZnAl ₂ O ₄ , MgSiO ₃ , Mg _{2 SiO 4, Zn 2 SiO 4} , Zn 2 TiO 4, SrTiO 3, CaTiO 3, MgTiO 3, BaTiO 3, CaMgSi 2 O 6, SrAl 2 Si 2 O 8, BaAl 2 Si 2 O 8, CaAl 2 Si 2 O ₈ , Mg ₂ Al ₄ Si ₅ O ₁₈ , Zn ₂ Al ₄ Si ₅ O ₁₈ , AlN, Si ₃ N ₄ , SiC, and a composite oxide containing at least one selected from Al ₂ O ₃ and SiO ₂ (For example, spinel, mullite, cordierite) and the like, and can be selected in accordance with the application.

Examples of the glass powder include SiO ₂ —B ₂ O ₃ , SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ , SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ —MO (however, M Is Ca, Sr, Mg, Ba or Zn), SiO ₂ —Al ₂ O ₃ —M ₁ O—M ₂ O system (where M ₁ and M ₂ are the same or different, and Ca, Sr , Mg, Ba or Zn), SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ —M ₁ O—M ₂ O (where M ₁ and M ₂ are the same as above), SiO ₂ —B ₂ O ₃ —M ₃ O system (where M ₃ is Li, Na or K), SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ —M ₃ O system (where M ₃ is the same as above), A glass containing at least one selected from the group consisting of Pb glass, Bi glass, alkali metal oxide, alkaline earth metal oxide, and rare earth oxide is preferable. These glasses become amorphous glass when fired, and when fired, lithium silicate, quartz, cristobalite, cordierite, mullite, anorthite, serdian, spinel, garnite, willemite, dolomite, petalite and their Crystallized glass that precipitates at least one type of substituted derivative crystal is used.

When the ceramic powder and the glass powder are mixed, the ratio is a ratio used for a normal glass ceramic structure material, and is preferably 60:40 to 1:99 by weight. Examples of the auxiliary component include B ₂ O ₃ , ZnO, MnO ₂ , alkali metal oxides, alkaline earth metal oxides, rare earth metal oxides, and the like, which can be selected according to use.

  In addition, as a material when the ceramic structure of the present invention is used as a piezoelectric element, crystals of apatite type structure such as barium titanate or lead zirconate-lead titanate solid solution can be cited, specifically, Examples thereof include zirconate titanates such as lead zirconate titanate (PZT) and lead lanthanum zirconate titanate (PLZT), or lead titanate.

  On the other hand, as the resin binder of the green sheet, for example, acrylic (acrylic acid, methacrylic acid or a homopolymer or copolymer thereof, specifically an acrylic ester copolymer, a methacrylic ester copolymer) , Acrylic acid ester-methacrylic acid ester copolymer, etc.), homopolymers or copolymers of polyvinyl acetal, cellulose, polyvinyl alcohol, polyvinyl acetate, polyvinyl chloride, polypropylene carbonate, etc. It contains at least one selected from these.

  Specific examples of the acrylic type include, for example, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate. , Isobutyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, isononyl acrylate, isononyl methacrylate, isodecyl acrylate, isodecyl methacrylate, etc. These acrylic esters and methacrylates A copolymer containing a carboxylic acid group, an alkylene oxide group, a hydroxyl group, a glycidyl group, an amino group or an amide group as a copolymer component is preferably used as the copolymer having a kill ester as the main chain. Can do.

  Examples of those having a carboxylic acid group include acrylic acid, methacrylic acid, maleic acid, itaconic acid, and fumaric acid. Examples of those having alkylene oxide include methylene oxide, ethylene oxide, and propylene oxide. As those having a hydroxyl group, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxybutyl acrylate, 2-hydroxybutyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerin monoacrylate, glycerin monomethacrylate, trimethylolpropane There are triacrylate, trimethylolpropane trimethacrylate, etc., and those having a glycidyl group include glycidyl Examples of those having an amino group or an amide group include dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, N-tert-butylaminoethyl acrylate, N-tert- Examples include butylaminoethyl methacrylate, acrylamide, cyclohexyl acrylamide, cyclohexyl methacrylamide, N-methylol acrylamide, and diacetone acrylamide.

  Other copolymerizable acrylonitrile, styrene, ethylene, vinyl acetate, n-vinylpyridone and the like may be copolymerized with these copolymers having acrylic acid ester or methacrylic acid alkyl ester as the main chain.

  Specific examples of the polyvinyl acetal type include polyvinyl butyral, polyvinyl ethylal, polyvinyl propylal, polyvinyl octylal, polyvinyl phenylal, and derivatives thereof.

  Specific examples of the cellulose type include methylcellulose, ethylcellulose, carboxymethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, nitrocellulose, and cellulose acetate.

  Next, as a conductor paste for forming a conductor portion such as a metallized wiring or a via conductor, for example, one or two metal powders such as Au, Cu, Ag, Pd, W, Mo, Ni, Al, and Pt are used. The above is mentioned, and in the case of two or more kinds, any form such as mixing and alloying may be used. What mixed these resin powders with the resin binder, the solvent, the plasticizer, the dispersing agent, etc. can use it conveniently.

  Examples of the resin binder for the conductive paste include acrylic, polyvinyl acetal, and cellulose homopolymers or copolymers, and contains at least one selected from these.

  Specific examples of acrylics include homopolymers or copolymers of acrylic acid, methacrylic acid or their esters, specifically acrylic ester copolymers, methacrylic ester copolymers, acrylic ester-methacrylic acid An ester copolymer may be used, and a hydroxyl group, a carboxylic acid group, an alkylene oxide group, a glycidyl group, an amino group, an amide group, or the like may be appropriately introduced into these copolymers. By introducing these, the effect of improving the dispersibility with ceramics and the effect of improving the viscosity and thixotropy can be expected. In addition, styrene, α-methylstyrene, acrylonitrile, ethylene, vinyl acetate, polyvinyl alcohol can be copolymerized with acrylic resin as long as the performance such as thermal decomposability and solubility in various solvents is not impaired. , N-vinylpyrrolidone or the like may be introduced as appropriate. Among these acrylic resins, one or two or more kinds can be appropriately selected and used as necessary.

  Examples of the conductive paste solvent include terpineol, dihydroterpineol, ethyl carbitol, butyl carbitol, carbitol acetate, butyl carbitol acetate, diisopropyl ketone, methyl cellosolve acetate, cellosolve acetate, butyl cellosolve, and butyl cellosolve acetate. , Cyclohexanone, cyclohexanol, isophorone, cypropylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, butyl carbitol methyl-3-hydroxyhexanoate, trimethylpentanediol monoisobutyrate, pine oil, mineral spirits, etc. A high boiling point solvent can be suitably used.

  The resin binder is preferably mixed at a ratio of 0.5 to 15.0 parts by weight with respect to 100 parts by weight of the metal powder, and the organic solvent is mixed at a ratio of 5 to 100 parts by weight with respect to 100 parts by weight of the solid component and the resin binder. In addition, you may add some inorganic components, such as glass powder and oxide powder, in this conductor paste. This conductor paste is printed on the green sheet in a predetermined pattern using a known printing method such as a screen printing method or a gravure printing method.

  A green sheet laminate is produced by applying or transferring an appropriate adhesive composed of a resin binder, solvent, and plasticizer to the green sheet thus obtained and then pressing and laminating with other green sheets to laminate them. To do. A ceramic structure is obtained by firing the obtained green sheet laminate under predetermined conditions.

  Next, FIG. 1 is a process diagram for explaining a method for producing a resin sheet-green sheet composite in which a resin sheet is fitted into a green sheet, and FIG. 1 is a diagram for explaining a method for producing a ceramic structure according to the invention. A process diagram is shown in FIG. 2, and a method for manufacturing a ceramic structure will be described in detail below.

<Resin sheet-green sheet composite>
As shown in FIG. 1, the resin sheet-green sheet composite according to the method of the present invention is configured by fitting a resin sheet 2 that is thermally decomposed during the firing process into the through hole 3 of the green sheet 1 before pressure lamination. Yes. Thereby, since the bottom part of a recessed part or a cavity is pressurized through the resin sheet 2 in the step which pressurizes and laminates, a swelling and a deformation | transformation do not generate | occur | produce. Further, a high lamination pressure can be applied so that delamination does not occur in the green sheet laminate. In addition, regarding the size of the recess or the cavity applicable to the method of the present invention, a size from a fine one to a relatively large one can be applied as long as the resin sheet-green sheet composite can be produced. . Further, even when the side wall surrounding the recess 7 or the cavity 10 shown in FIG. 2 is thin and weak, it is possible to prevent a problem that the thin side wall around the recess 7 or the cavity 10 is deformed during pressurization or raw processing. .

  Next, a method for fitting the resin sheet 2 into the through hole 3 of the green sheet 1 will be described. First, the through-hole 3 of the green sheet 1 is formed by a punching device mainly composed of an upper mold 4 that is a driving part of the punching mold and a lower mold 6 that is a fixing part of the punching mold. Specifically, as shown in FIG. 1 (a), the green sheet 1 is placed on a lower mold 6 provided with an opening 5, and the upper mold 4 is placed in green as shown in FIG. 1 (b). A punching process is performed by driving the sheet 1 from above to below to form a through hole 3 as shown in FIG. 1C, and the green sheet 1 having the through hole 3 is obtained. Note that the punching device may be one in which the upper mold 4 is fixed and the lower mold 6 can be driven.

  Next, as shown in FIG. 1 (d), using the same punching device, the resin sheet 2 is stacked on the green sheet 1 in which the through holes 3 are formed, and as shown in FIG. By driving 4, punching of the resin sheet 2 and fitting of the punched resin sheet 2 into the through hole 3 are performed simultaneously. Subsequently, an excess portion of the resin sheet 2 is removed, and a resin sheet-green sheet composite A in which the resin sheet 2a is fitted into the through hole 3 as shown in FIG. 1 (f) can be obtained.

<Ceramic structure>
Then, the manufacturing method of the ceramic structure which has the recessed part 7 in the surface and the cavity 10 inside is demonstrated with the process drawing of FIG. First, a resin sheet-green sheet composite A1 in which the resin sheet 2a produced by the above-described method is fitted, and a green sheet B1 in which a wiring conductor layer 8 made of a metallized layer and a via conductor 9 are formed are illustrated in FIG. 2 (a) to (c) are laminated to produce a ceramic green sheet laminate C. Specifically, as shown in FIG. 2A, a resin sheet-green sheet composite A1 and a green sheet B1 are laminated at predetermined positions, and as shown in FIG. A plurality of laminates of the green sheet composite A1 and the green sheet B1 are produced. Next, as shown in FIG. 2C, a plurality of the laminates are laminated to produce a ceramic green sheet laminate C.

  In the initial stage of the subsequent firing step, as shown in FIG. 2 (d), the resin sheet 2a fitted in the ceramic green sheet laminate C is thermally decomposed and removed through the state D including the pyrolytic melt 2a ′. Further, by sintering the ceramic, as shown in FIG. 2 (e), a ceramic structure E having a recess 7 on the surface and a cavity 10 inside can be obtained.

  By such a manufacturing method of the present invention, the concave portion 7 on the surface and the bottom portion of the internal cavity 10 are not pressurized and the bottom portion of the concave portion 7 and the cavity 10 does not bulge. This enables the ceramic structure E that does not cause delamination.

  In addition, in the method for producing a ceramic structure of the present invention, a method of punching and fitting a resin sheet-ceramic green sheet composite may be used in combination. That is, instead of the green sheet 1 in FIG. 1B, first, the resin sheet 2 is penetrated with a punching die, and then the green sheet 1 is fitted into the through hole of the obtained resin sheet 2- A ceramic green sheet composite may be used in combination.

  In this case, a through hole is formed in the resin sheet using a punching die, and then the ceramic green sheet is placed on the resin sheet on which the through hole is formed and pressed from the ceramic green sheet side using the punching die. In order to manufacture a resin sheet-ceramic green sheet composite by fitting a part of the ceramic green sheet into the through hole of the resin sheet, the ceramic green sheet is added to the ceramic green sheet for forming the recess or cavity side wall of the ceramic structure. Since the shearing history by the punching die is only once, it is possible to further suppress the deformation of the side wall of the recess or the cavity, which is effective in realizing the recess or the side wall of the cavity having a particularly excellent squareness. Means. Therefore, even when the side wall of the recess or cavity is thin and weak, a ceramic structure having a recess or an internal cavity formed from a sintered surface having high squareness, flatness, and dimensional accuracy can be obtained.

<Resin sheet>
Next, the manufacturing method of the resin sheet 2 (2a) used for the manufacturing method of the ceramic structure of this invention is described. The resin sheet 2 (2a) contains air bubbles, and preferably further contains a resin binder and at least one of a plasticizer and a lubricant. As the characteristics required for the resin sheet 2 (2a), punching workability (shearing workability), pressure equalization lamination in the lamination process, and thermal decomposability in the firing process are important.

  First, in order to obtain good punching workability, air bubbles are introduced into the resin sheet, and further, by using at least one of a plasticizer and a lubricant, the flexibility, flexibility, strength, and elongation of the resin sheet are improved. adjust. In the shearing process such as punching or cutting of the resin sheet, the shearing process can be easily performed because cracks are easily generated in the shearing direction through the bubbles.

(Bubbles)
A method for forming bubbles on the resin sheet 2 (2a) will be described. The air bubbles can be included in the resin sheet 2 (2a) by making the resin binder described below porous. The method for forming bubbles by making the resin binder porous is not particularly limited. For example, a method using phase separation of a polymer solution, such as a heat-induced phase separation method or a non-solvent-induced phase separation method, or generated at the time of polymer formation. Chemical reaction generation gas utilization methods such as gas use, pyrolysis reaction generation gas utilization, mechanical physical methods and chemical methods such as various foaming agents, etc., resin beads filled between resin beads Examples include the use of voids, the use of expandable resin beads, the use of porous resin beads, the use of resin beads such as the use of hollow beads, and the microcellular plastic method using carbon dioxide and nitrogen in a supercritical state. .

Next, the size of the bubbles in the resin sheet 2 (2a) will be described. Considering processability when punching a porous resin sheet into a fine complex shape and pressure equalization lamination in the lamination process of the resin sheet-green sheet composite, the size of the bubbles is fine and the bubbles are uniform. Desirably distributed. Specifically, the average diameter of the bubbles is 100 μm or less, more preferably 50 μm or less. For this reason, among the above-described bubble forming methods, it is preferable to use a microcellular plastic method, or to make it porous by using various resin beads such as expandable resin beads, porous resin beads, and hollow beads.

  The average diameter of the bubbles is preferably (1/3) t or less with respect to the thickness t of the resin sheet. When the average diameter of the bubbles is larger than (1/3) t with respect to the thickness t of the resin sheet, the fine processability of the resin sheet is lowered and the rigidity of the resin sheet itself is also lowered. In this case, the pressure is not effectively transmitted from the resin sheet to the surrounding green sheet, so that the pressure equalization lamination property is lowered. In addition, the thickness t of the resin sheet concerning this invention is not specifically limited, What is necessary is just the thickness which can perform above-mentioned equalization lamination | stacking.

  Such a method for producing a porous resin sheet may be appropriately selected according to the purpose because it varies depending on the selection of the various porous methods described above. For example, extrusion molding, injection molding, tape molding, etc. Can be mentioned.

  The porosity of the resin sheet 2 (2a) is 40 to 80%, preferably about 50 to 70%, in order to obtain good punchability. The porosity is the percentage of bubbles contained in the resin sheet 2 (2a) as a percentage. For example, the cross section of the resin sheet 2 (2a) is observed with a scanning electron microscope, and the bubbles occupy the entire field of view. It can be calculated from the ratio.

(Resin binder)
The resin binder used for the resin sheet 2 (2a) may be any resin binder that has excellent thermal decomposability, and is preferably acrylic or α-methylstyrene. As acrylic resins, homopolymers or copolymers of acrylic acid, methacrylic acid or their esters, specifically acrylic ester copolymers, methacrylic ester copolymers, acrylic ester-methacrylic ester copolymers Examples include coalescence. As such, for example, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, isobutyl There are methacrylate, t-butyl acrylate, t-butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, and the like.

  Among these acrylic resins, one or two or more kinds can be appropriately selected and used as necessary. Among these, an isobutyl methacrylate-based (IBMA) or methyl methacrylate-based (MMA) resin binder alone or a copolymer is particularly preferable. Further, styrene, α-methylstyrene, acrylonitrile, ethylene, etc., which can be copolymerized with an acrylic resin, may be appropriately introduced as long as the thermal decomposability is not impaired. It contains at least one selected from these.

(Plasticizer)
Furthermore, the plasticizer added to give flexibility and flexibility to the resin sheet 2 (2a) may be any plasticizer that does not impair the thermal decomposability of the resin sheet. For example, dimethyl phthalate, dibutyl phthalate, di Phthalates such as 2-ethylhexyl phthalate, diheptyl phthalate, di-n-octyl phthalate, diisononyl phthalate, diisodecyl phthalate, butyl benzyl phthalate, ethyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, di- There are aliphatic ester systems such as 2-ethylhexyl adipate and dibutyl diglycol adipate, which contain at least one selected from these. Of these, plasticizers such as phthalic acid esters such as dibutyl phthalate (DBP) and di-2-ethylhexyl phthalate (DOP) are preferable.

(Lubricant)
Furthermore, the lubricant added to improve the shear processability of the resin sheet 2 (2a) may be any lubricant that does not impair the thermal decomposability of the resin sheet 2 (2a). For example, diethylene glycol, triethylene glycol, Polyethylene glycol, diethylene glycol methyl ether, triethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol-n-butyl ether, triethylene glycol-n-butyl ether, ethylene glycol phenyl ether, ethylene glycol-n-acetate, diethylene glycol monohexyl ether, diethylene glycol mono Ethylene glycols such as vinyl ether, dipropylene glycol, tripropylene glycol, polypropylene glycol , Dipropylene glycol methyl ether, tripropylene glycol methyl ether, dipropylene glycol monoethyl ether, dipropylene glycol-n-butyl ether, tripropylene glycol-n-butyl ether, propylene glycol phenyl ether, ethylene glycol benzyl ether, ethylene glycol isoamyl ether And glycerin such as glycerin, diglycerin, and polyglycerin. Among them, polyethylene glycol (PEG) and glycerin are preferable.

  Natural wax and synthetic wax may be used as a lubricant. Acrylic resin, which is a general resin binder, depolymerizes monomer units during thermal decomposition and lowers its molecular weight, so a large amount of decomposition gas is generated, whereas many waxes become large molecules during thermal decomposition. Since it decomposes and vaporizes with a large molecular weight, the generation amount of decomposition gas can be reduced, and there is an effect of preventing deformation of the surrounding green sheet or generation of cracks due to the generation pressure of the decomposition gas. Examples of natural waxes include plant waxes such as carnauba wax, candelilla wax, sugar wax, rice wax, wood wax, bayberry wax, ocully wax, esparto wax, jojoba oil, beeswax, insect wax, and whale wax. Animal waxes such as lanolin wax, petroleum waxes such as paraffin wax, microcrystalline wax and petrolatum, mineral waxes such as ozokerite wax, ceresin and montan wax. Of these, carnauba wax, paraffin wax, and microcrystalline wax are preferable. Furthermore, synthetic waxes include, for example, oxidized natural wax, amide wax, polyethylene wax, oxidized polyethylene wax, acid-modified polyethylene wax, polypropylene wax, acid-modified polypropylene wax, acid-modified polypropylene wax, Fischer-Tropsch wax, and ethylene-vinyl acetate copolymer. Examples thereof include a copolymer, an ethylene-acrylic acid copolymer, and an ethylene-methacrylic acid copolymer. Of these, polyethylene wax, ethylene-acrylic acid copolymer, and ethylene-methacrylic acid copolymer are preferable. It contains at least one selected from these.

  These plasticizers and lubricants are preferably limited to the minimum necessary amount. For example, at the time of firing a product in which a conductor portion such as a fine wiring conductor is formed at a site where the resin sheet contacts, a large amount of plasticizer or lubricant remains in the composition of the molten resin sheet 2 (2a). If it is, it becomes easy to dissolve the resin binder in the conductor part in contact therewith, and there is a possibility that defects such as deformation or disconnection of the conductor part may occur due to a decrease in the strength of the conductor part. Also, some of the solid wax and the like need to be careful because some of them cause volume expansion when heated and melted.

(Resin beads)
In the method of the present invention, powdered resin beads may be added in order to achieve better punching workability and pressure uniformity lamination in the lamination process. In this case, when shearing such as punching or cutting of the resin sheet, cracks are easily generated in the shearing direction through the resin layer or bubbles existing between the added resin beads, so that shearing can be easily performed. Further, since the propagation of cracks generated in directions other than the shearing direction is suppressed by the presence of resin beads and bubbles, the propagation of cracks in the direction other than the shearing direction can be suppressed, and a desired shape can be sheared. As a result, since a resin sheet having substantially the same shape as the through hole can be fitted, it is possible to prevent deformation of the green sheet when the green sheet is pressed and laminated. In addition, since the rigidity of the resin sheet itself is improved by the presence of the resin beads that are rigid bodies, it is possible to further maintain the pressure equalization stackability even when stacked at a high pressure.

  The resin beads that can be added are not particularly limited as long as they exhibit good thermal decomposition behavior at the time of firing, but are preferably acrylic or α-methylstyrene. The average particle size of the resin beads is preferably 1 to 20 μm. When the average particle diameter is less than 1 μm, the aggregation of resin beads becomes a problem, and when the average particle diameter exceeds 20 μm, protrusions are likely to occur on the surface of the resin sheet 2 (2a). In addition, you may use the thing of a hollow structure as a resin bead. In this case, there is an advantage that the sheet attack to the green sheet is reduced because the thermal decomposition melt of the resin sheet is small during the firing step. Therefore, when using resin beads having a hollow structure, the same effect as when bubbles are introduced into the resin sheet can be expected.

  The amount of resin beads added is such that the green sheet is not deformed or cracked by the melt or gas generated by the resin beads at the time of binder removal. It is good that it is about 50-150 weight part with respect to a part.

<Thermal decomposition>
On the other hand, the thermal decomposability of the resin sheet 2 (2a) is superior to the resin binder contained in the green sheet on which the resin sheet 2 (2a) is placed and the resin binder contained in the conductor portion in contact with the resin sheet. It is preferable that it is easy.

  Specifically, it is preferable that the thermal decomposability of the resin sheet 2 (2a) is superior to the resin binder contained in the green sheet in contact with the resin sheet 2 (2a). That is, as the resin binder in the green sheet is thermally decomposed (degreased) and the amount of the remaining resin binder in the green sheet is decreased, the strength of the green sheet is decreased, and the resin sheet 2 is delayed with respect to the brittle green sheet. When (2a) is thermally decomposed, the melt of the high-viscosity resin sheet 2 (2a) liquefied by heating is accompanied by vibration motions up and down and left and right accompanying boiling on the surface of the green sheet that has become brittle after degreasing. However, since the surface of the green sheet in contact with the thermally decomposed portion is partially removed, the phenomenon that the surface is eroded and destroyed can be eliminated.

  On the other hand, when a conductor part such as a wiring conductor is formed at a site where the resin sheet comes into contact, the thermal decomposability of the resin sheet 2 (2a) is superior to the resin binder contained in the conductor part in contact therewith. preferable. More specifically, the 20% weight reduction temperature of the resin binder contained in the conductor portion in contact with the resin sheet 2 (2a) is set to 20% of the resin binder contained in the green sheet on which the resin sheet 2 (2a) is placed. What is necessary is just to set so that it may become more than weight reduction temperature. Thereby, after most of the resin sheet 2 (2a) is thermally decomposed at the time of firing, thermal decomposition of the resin binder for the conductor paste contained in the conductor portion is started, so that a large amount of the molten resin sheet 2 (2a) In the stage where the composition of) remains, since the resin binder in the conductor part in contact with the composition has not started thermal decomposition, the strength of the conductor part is sufficiently maintained. Therefore, a highly reliable ceramic structure free from defects such as deformation or disconnection of the conductor by dissolving the resin binder in the conductor by the melted resin sheet 2 (2a) composition is produced. It becomes possible to do.

On the other hand, the resin sheet 2 (2a) has a structural and material composition such as a combination of a porous resin sheet containing bubbles and a dense resin sheet containing no bubbles, or a combination of resin sheets made of different materials. The resin sheet 2 can also be configured as a resin sheet laminate in which a plurality of resin sheets having different thermal decomposability are laminated. Thereby, thermal decomposability, mechanical properties, viscoelasticity, and the like can be changed inside the resin sheet 2 (2a). The resin sheet laminate may be formed by laminating a plurality of the resin sheet-green sheet composites.
Giving a difference in thermal decomposability is particularly effective for the following reasons.

  The thermal decomposition of the resin sheet 2 (2a), which is a resin sheet laminate, is preferably started sequentially from the upper layer portion toward the lower layer portion, and finally the thermal decomposition is completed at the lowermost layer portion. That is, it is preferable that the upper layer part of the resin sheet 2 is superior to the lower layer part in terms of thermal decomposability. Furthermore, in order to give a time difference to the thermal decomposition, it is preferable to provide a multi-stage debinding process in the initial stage of the firing process.

  The effect by giving a difference in the thermal decomposability of the upper layer part of the resin sheet 2 and a lower layer part is demonstrated. At the stage where the upper layer resin sheet fitted in the green sheet laminate is thermally decomposed and removed in the first debinding step, the adjacent green sheet and conductor are protected by the lowermost layer resin sheet, It is possible to prevent damage caused by the melt generated in the thermal decomposition process of the upper layer resin sheet. By removing the lowermost layer resin sheet in the subsequent second debinding process, the green sheet and the conductor part adjacent to the resin sheet can be minimized from damage by the melt of the resin sheet. These effects are particularly remarkable when the amount of the resin sheet 2 fitted into the recess 7 or the cavity 10 of the green sheet shown in FIG. That is, when the amount of the resin sheet 2 fitted into the concave portion 7 or the cavity 10 of the green sheet is large, a bad influence due to the melt during the thermal decomposition of the resin sheet 2 described above or a large amount occurs when the melt is thermally decomposed. There is a possibility of being adversely affected by cracks and deformation of the green sheet due to the pressure of the cracked gas.

  As a means for giving a difference in the thermal decomposability of the resin sheet 2 in this way, for example, changing materials such as a resin binder constituting the upper layer portion and the lowermost layer portion can be mentioned. That is, the material of the upper layer resin sheet is selected to be more thermally decomposable than the lowermost layer resin sheet. Moreover, in addition to the method of individually preparing and combining a plurality of resin sheets so as to have a difference in thermal decomposability as described above, the upper layer is formed by a method such as tape molding or coating on the uppermost resin sheet. By forming a part of the resin sheet, the thermal decomposability may be changed in an inclined manner inside the resin sheet 2. Under the present circumstances, you may use combining the porous resin sheet containing the bubble used in the manufacturing method of this invention, and the resin sheet which does not contain a bubble.

From the above, in the present invention, the thermal decomposability of each material forming the green sheet laminate is determined by thermogravimetric differential thermal analysis (TG / DTA) up to 600 ° C. at a temperature rising rate of 10 ° C./min in an N ₂ atmosphere. If performed in a differential high-temperature thermal balance (Rigaku Co., Ltd. "TG8120"), a 80% weight loss temperature of the upper portion of the resin sheet 2 T _a ° C., 80% weight loss temperature of the lowermost layer portion T _b ° C., 20% weight reduction temperature of the resin binder in the green sheet in which the resin sheet 2 is placed upon the T _c ° C., preferably satisfy the relation of _{T a <T b ≦ T c} . Further, it is preferable that the resin sheet 2 (2a) thermally decomposes 99% by weight or more at 600 ° C. or less.
On the other hand, when a conductor portion such as a wiring conductor is formed at a site where the resin sheet 2 comes into contact, it is preferable to set the 20% weight reduction temperature of the resin binder contained in the conductor portion to T _c ° C or higher.

The temperature profile of the binder removal process during firing of the ceramic structure of the present invention is maintained at _a temperature around _Ta ° C., which is the temperature at which most of the upper layer portion of the resin sheet is thermally decomposed, for a predetermined time, for example, 1 to 6 hours. A first debinding step in which the upper layer portion of the resin sheet is sufficiently thermally decomposed and removed, and then the _Tb ° C. is maintained for a predetermined time, for example, 1 to 6 hours to sufficiently thermally decompose and remove the lowermost layer portion of the resin sheet. It is preferable to divide the process into two debinding steps and then a third debinding step which is performed while maintaining a temperature exceeding T _c ° C for a predetermined time, for example, 1 to 6 hours. Such holding time varies within the above range depending on the amount and material of the resin binder.

Thereby, after most of the resin sheet 2 (2a) is thermally decomposed, the resin binder of the green sheet and the conductor portion can start to thermally decompose, and the melt of the resin sheet 2 (2a) remains. In the stage, since the resin binder in the green sheet and the conductor part has not started thermal decomposition, sufficient strength can be maintained. Therefore, the melt of the resin sheet 2 (2a) can be prevented from eroding and destroying the green sheet and the conductor portion that are in contact therewith. Moreover, the temperature exceeding T _c ° C. to maintain the predetermined time can be green sheet and the conductor portion of the resin binder also sufficiently thermally decomposed.

<Volume>
Next, the volume of the resin sheet 2 fitted into the surface recesses and internal cavities in the method for producing a ceramic structure having surface recesses and internal cavities of the present invention will be described. The volume of the resin sheet 2 fitted into the concave portion on the surface or the internal cavity is 0.8 V to 1.1 V (occupied volume) with respect to the void portion serving as the concave portion and the void portion serving as the cavity of the ceramic green sheet having the volume V. (Including the volume of bubbles contained in the resin sheet)). Actually, the optimum volume ratio of the resin sheet to be fitted slightly differs depending on the lamination conditions such as the lamination pressure and the lamination temperature, but the optimum volume ratio of the resin sheet may be arbitrarily selected within the above-mentioned range.

Furthermore, the volume V _{liq. In} the molten state when the resin sheet is thermally decomposed is 0.2V to 0.6V. The resin sheet melt volume can be adjusted mainly by the volume ratio of bubbles introduced into the resin sheet. Here, when the ratio of the bubbles in the resin sheet is increased so that V _liq. Is set to be lower than 0.2 V, the strength of the resin sheet is decreased. It may be difficult to process complicated shapes. Further, when the lamination process is performed using the resin sheet-green sheet composite A shown in FIG. 1 (f) in which a resin sheet is fitted into a green sheet, the pressure equalization lamination becomes difficult due to the low strength of the resin sheet. In some cases, this may cause various problems and the effects of the method of the present invention cannot be fully exhibited. On the other hand, when the ratio of air bubbles in the resin sheet is reduced so that V _liq. Is set to be higher than 0.6 V, the strength of the resin sheet is increased, which may reduce the workability of the resin sheet. is there. Further, when the resin sheet fitted into the green sheet is thermally decomposed, the void volume of (V-V _liq. ) Is small, so that it is difficult to release the thermally decomposed gas of the resin sheet to the outside without difficulty. Therefore, there is a risk of adverse effects such as cracking and deformation of the surrounding green sheet due to the pressure of the pyrolysis gas of the resin sheet.

  On the other hand, the resin sheet 2 is placed in a through hole formed in a portion that becomes the concave portion 7 and a portion that becomes the cavity 10 of the green sheet, and the lower surface of the resin sheet 2 is in contact with at least the entire bottom surface of the through hole. It should be placed or installed. In this case, a lamination pressure can be applied to the entire bottom surface of the through hole, and deformation of the bottom surface can be prevented. In addition, the resin sheet 2 is preferably placed or installed so that the lower surface and the side surface of the resin sheet 2 are in contact with at least the entire bottom surface and the entire lower side of the inner surface of the through hole. In this case, even when the side surface side of the through hole is weak, deformation or destruction of the side surface side of the through hole due to the stacking pressure can be prevented. Furthermore, the resin sheet 2 is preferably placed or placed (filled) so that the lower surface and the side surface of the resin sheet 2 are in contact with the entire bottom surface and the entire inner surface of the through hole. In this case, deformation of the entire inner surface of the through hole can be prevented.

  The concave portion 7 and the internal cavity 10 on the surface of the ceramic structure manufactured in this way according to the method of the present invention are in a cross section perpendicular to the longitudinal direction in a state in which the inner surface is composed of a sintered surface as sintered. The deviation of the cross-sectional area is ± 5% or less, the flatness of the inner surface is 30 μm or less, and the recesses and cavities are square in cross section perpendicular to the longitudinal direction, and the flatness of the bottom surface is 30 μm or less. The flatness of the side surface is 30 μm or less, the curvature radius of the corner between the bottom surface and the inner surface in the cross section perpendicular to the longitudinal direction is 50 μm or less, and the angle between the inner surface and the bottom surface is 90 ° ± 3 ° Is preferred. The flatness referred to here is based on what is defined in Japanese Industrial Standards (for example, Reference 1: “JIS Industrial Terminology Dictionary (4th edition)”, p1747, 1995, Reference 2. : "JIS B6191 (Machine tool-Static accuracy test method and machine accuracy test method general rules)", p20-26, 1999).

  As described above, the recess or cavity in the ceramic structure of the method of the present invention is composed of a sintered surface having a high squareness, flatness, and dimensional accuracy, so that it is not necessary to perform special planarization treatment such as cutting or surface treatment. . Accordingly, when an electronic component or the like is mounted in the concave portion on the surface or the internal cavity, it is possible to prevent problems such as bonding failure. Furthermore, since the recess or cavity in the ceramic structure of the present invention has a small cross-sectional area deviation, when the ceramic structure is a microchemical chip or the like as a fluid flow path, the flow rate and flow rate can be constant. Become.

  On the other hand, since the radius of curvature can provide a ceramic structure exactly as designed, when an electronic component is mounted in a recess or internal cavity on the surface, the effective volume of the recess or cavity can be maximized. Mounting density can be increased. Furthermore, when the internal cavity is used as a fluid flow path, it is possible to realize a flow rate and a flow velocity as designed.

  The recesses or cavities in the ceramic structure of the method of the present invention are made of a sintered surface having a high squareness, flatness and dimensional accuracy, so there is no need for special planarization treatment such as cutting or surface treatment. However, if necessary, the inner surface of the recess or cavity may be lightly polished or cut. In that case, higher squareness, flatness and dimensional accuracy can be obtained. Furthermore, when using the ceramic structure of the present invention as a microchemical chip, resistance to various chemicals, wettability, water repellency, surface tension, elution of constituent components, surface polarity, surface functional groups, etc. Various surface treatments may be performed in consideration of factors that affect the fluid to be treated.

  As an application example of the ceramic structure having a complicated shape having at least one of the concave portion 7 on the surface and the internal cavity 10 according to the method of the present invention, a microchemical chip can be cited. With the progress of microfabrication technology, the development of building a flow system using microfabricated chips, etc., for chemical and biochemical analysis, production operations and reactions is progressing. Microfluidics, μ-TAS (Micro Total Analysis System), MEMS (Micro Electro Mechanical Systems), BioMEMS (Bio Micro Electro Mechanical Systems) and the like are being applied.

  For example, in μ-TAS, a groove is generally formed on the surface of a chip of glass, silicon, ceramic or the like of about 10 centimeters to several centimeters square, and a fluid to be processed is passed through the groove to separate, analyze, and react. , Production, purification, genetic analysis, etc. Miniaturization of the flow system is effective in reducing the amount of fluid to be processed, speeding up, improving efficiency by increasing the specific surface area, and improving productivity.

  The flow system consists of a flow path, a liquid delivery mechanism such as a pump, a liquid reservoir, a valve, a bent pipe, a branch pipe, a merge pipe, an expansion pipe, a reaction tank, a separation area, a detection flow cell, a heating section, a cooling section, a pH adjustment section, It consists of a laser irradiation unit, a radiation irradiation unit, an inspection unit, and the like. In addition, by mounting electrodes, electronic circuits, various sensors, various antennas, etc., electrophoresis of the fluid to be processed, wireless transmission of various data, and the like are possible.

  Furthermore, in order to integrate, integrate, miniaturize, and enhance the functions of machinery, electronics, light, chemistry, biochemistry, etc., a concave structure such as metallized wiring and flow paths is mixed on the same substrate. It is important to use a three-dimensional stacking technique and a technique for forming a plurality of substrates. These techniques can be realized by applying the manufacturing method of the present invention.

  In addition, although the microchemical chip produced by applying the manufacturing method of the present invention is made of ceramic, it is combined with a microchemical chip formed of other materials excellent in chemical durability, transparency, electrical insulation and the like. Also good. Examples thereof include glass such as glass and quartz glass, resins such as acrylic resin, polycarbonate and silicone rubber, composite materials thereof, or combinations thereof. These materials take into account factors that affect the fluid to be treated, such as resistance to acids, alkalis, various chemicals, etc., wettability, water repellency, surface tension, elution of constituent components, surface polarity, and surface functional groups. It is preferable to select them.

  The fluid to be treated used in the microchemical chip obtained by applying the production method of the present invention includes pure water, various aqueous solutions, colloidal liquid, suspension, blood, urine, body fluid, nucleic acids (DNA, RNA, etc.) ), Proteins (antigens, antibodies, lectins, adhesins, receptors for various physiologically active substances, peptides, etc.), sugars, cells, various culture solutions, culture extracts, reaction solutions, organic solvents, various chemicals, and mixtures thereof Although a liquid etc. can be used, it is not limited to this.

On the other hand, examples of other uses of the ceramic structure having a complicated shape having at least one of the concave portion 7 on the surface and the internal cavity 10 according to the present invention include the following.
For example,
(1) A waveguide or waveguide circuit board formed by forming a conductor layer on the inner surface of the recess 7 or the cavity 10, or a circuit wiring, a capacitor, an inductance, or the like formed by filling the recess 7 or the cavity 10 with a conductor. Wiring board,
(2) A semiconductor integrated circuit element such as LSI, a piezoelectric vibrator such as a crystal vibrator, a light receiving element such as a photodiode or a CCD element, various sensor elements, using the waveguide circuit board or wiring board of (1). Electronic component storage package for storing various electronic components,
(3) The waveguide of (1), a waveguide circuit, a millimeter wave circuit using a wiring board, a millimeter wave radar for automobiles using the millimeter wave circuit,
(4) A non-radiative dielectric line in which a conductor layer is formed on the bottom surface of the recess 7 and a dielectric line is installed inside the recess 7 and the recess 7 is closed with a conductor plate, an automobile using the same, etc. For millimeter wave radar,
(5) A fuel cell or fuel cell reformer in which a flow path for flowing oxygen gas, hydrogen gas, alcohol, hydrocarbon gas, etc. is formed;
(6) An ink jet printer head made of a piezoelectric material, which discharges ink to the outside by a piezoelectric effect from a cavity 10 or a channel formed inside,
(7) A piezoelectric element such as an actuator made of a piezoelectric material and having a recess 7 or a cavity 10 formed thereon,
(8) Optical application parts and substrates in which a conductor layer for mounting electronic components and the like is formed on the inner surfaces of the recesses 7 and the cavity 10; optical application parts and substrates in which an optical path is formed by the recesses 7 and the cavity 10;
(9) A radio wave absorber in which a plurality of cavities 10 having a fractal structure are formed,
(10) Filters in which a honeycomb-shaped cavity 10 such as DPF (Diesel Particulate Filter) is formed,
(11) Display components in which a large number of recesses 7 such as a back plate such as a plasma display panel (PDP) and a field emission display (FED) are formed,
Etc.

EXAMPLES Hereinafter, although an Example is given and the method of this invention is demonstrated in detail, this invention is not limited to a following example.
[Examples 1 to 5 and Comparative Example 5 ]
<1. Preparation of green sheet>
11 parts by weight of a binder of a copolymer composition of methyl acrylate and methyl methacrylate per 100 parts by weight of a glass ceramic raw material powder composed of SiO ₂ , Al ₂ O ₃ , CaO, ZnO, B ₂ O ₃ , phthalate as a plasticizer 5 parts by weight of dibutyl acid was added, and toluene was mixed as an organic solvent for 36 hours by a ball mill to prepare a slurry. The obtained slurry was molded and dried by a doctor blade method to produce green sheets having a thickness of 0.25 mm and 1.5 mm. Next, a through hole (through hole) having a diameter of 200 μm was formed in a part of the green sheet by punching.

  Subsequently, the through-hole filling conductor paste described below was filled into the through-hole formed in the green sheet by a screen printing method. Next, a wiring pattern having a film thickness of 15 μm is printed and applied by screen printing using the following conductive paste for wiring, followed by drying at 80 ° C. for 1 hour using a hot air drying furnace to form a metallized wiring. did.

<2. Preparation of conductor paste>
(2-1) Conductor paste for filling through holes (conductor paste for forming via conductors)
For 100 parts by weight of Cu powder, 2 parts by weight of a resin binder of a copolymer composition of methyl acrylate and methyl methacrylate (used in common with the green sheet) and 4 parts by weight of a mixed solvent of terpineol and butyl carbitol acetate 2 parts by weight of a phthalate ester plasticizer (a mixture of DOP: di-2-ethylhexyl phthalate and DBP: dibutyl phthalate) was added and mixed with stirring. Thereafter, a conductive paste was prepared by mixing with a three-roll mill until there were no aggregates such as Cu powder and resin binder.

(2-2) Conductive paste for wiring 3 parts by weight of a resin binder of a copolymer composition of methyl acrylate and methyl methacrylate (used in common with the green sheet), terpineol and butyl with respect to 100 parts by weight of Cu powder 10 parts by weight of a mixed solvent of carbitol acetate and 10 parts by weight of a phthalate ester plasticizer (mixture of DOP and DBP) were added, and these were stirred and mixed. Thereafter, a conductive paste was prepared by mixing with a three-roll mill until there were no aggregates such as Cu powder and resin binder.

<3. Production of ceramic structure using resin sheet>
The green sheet laminate of FIG. 2 was formed using the resin sheet 2. First, bubbles are introduced into a resin composition consisting of 3 parts by weight of DOP and 3.5 parts by weight of polyethylene glycol with respect to 100 parts by weight of resin binder of isobutyl methacrylate, and the average cell diameter and molten state volume shown in Table 1 are as follows. A resin sheet 2 having a thickness of 1.5 mm, which was prepared in a state of having, was prepared. Further, the resin sheet 2a was fitted into the green sheet A1 (length 50 mm × width 50 mm × thickness 1.5 mm, through hole portion: length 50 mm × width 5 mm × depth 1.5 mm) by the punching method of FIG.

  Subsequently, a green sheet A1 coated with an adhesive composed of an acrylic resin, a solvent, and a phthalate ester plasticizer and a green sheet B1 having a thickness of 0.25 mm are laminated at a pressure of 4.9 MPa. The green sheets were integrated to produce a green sheet laminate C having internal wiring. The occupied volume of the resin sheet 2a is 0.2 V to 0.6 V with respect to the void portion serving as the concave portion and the void portion serving as the cavity of the ceramic green sheet having the volume V (the occupied volume is included inside the resin sheet). (Including bubble volume).

Next, this green sheet laminate C is placed on an Al ₂ O ₃ setter and is heated to 310 ° C., which is near the 80% weight reduction temperature of the resin sheet 2a in a nitrogen, hydrogen, and steam mixed atmosphere firing furnace. For 3 hours to sufficiently remove the resin sheet 2a.

  After that, the temperature range exceeding 20% weight reduction temperature of the resin binder contained in the green sheet is maintained at 850 ° C. for 3 hours, further debinding is performed, and then baked at 950 to 1000 ° C. A ceramic structure having a recess structure and a hollow structure inside was prepared.

[Example 6 ]
The resin sheet 2 is composed of 6 parts by weight of DOP and 7 parts by weight of polyethylene glycol in which 100 parts by weight of resin beads of crosslinked isobutyl methacrylate having an average particle size of 10 μm are added to 100 parts by weight of the resin binder of isobutyl methacrylate. Bubbles were introduced into the resin composition to prepare a resin sheet 2 in which bubbles and resin beads having an average bubble diameter and a melted volume shown in Table 1 were mixed. Other conditions were the same as in Examples 1 to 5 , and a ceramic structure was produced.

[Example 7 ]
In the configuration of the resin sheet 2, a resin sheet having an upper and lower two-layer structure was produced. That is, the resin sheet constituting the upper layer part has a thickness of 1 mm by introducing bubbles into a resin composition composed of 3 parts by weight of DOP and 3.5 parts by weight of polyethylene glycol with respect to 100 parts by weight of the resin binder of isobutyl methacrylate. Prepared. On the other hand, in the resin sheet constituting the lowermost layer part, bubbles are introduced into the resin composition consisting of 3 parts by weight of DOP and 3.5 parts by weight of polyethylene glycol with respect to 100 parts by weight of the resin binder of n-butyl methacrylate. The thickness was adjusted to 0.5 mm. These were combined up and down to prepare a resin sheet 2 having a thickness of 1.5 mm and having an average cell diameter and a melted volume shown in Table 1. Other conditions were the same as in Examples 1 to 5 , and a green sheet laminate C was produced.

Next, this green sheet laminate C is placed on an Al ₂ O ₃ system setter, and in a mixed atmosphere firing furnace of nitrogen, hydrogen, and water vapor, an 80% weight reduction temperature T of the resin sheet constituting the upper layer portion _After holding for 3 hours at 310 ° C., which is near _a ° C., and sufficiently removing the upper layer resin sheet, the resin sheet at the lowermost layer portion is 3% at 330 ° C., which is about 80% weight reduction temperature T _b ° C. Holding for a time, the lowermost layer resin sheet was sufficiently removed.

Thereafter, the resin binder contained in the green sheet is held at 850 ° C., which is a temperature range exceeding the 20% weight reduction temperature T _c ° C., for 3 hours, further debinding, and subsequently fired at 950 to 1000 ° C. A ceramic structure was prepared.

[Comparative Examples 1 and 2]
Ceramic structures were produced in the same manner as in Examples 1 to 5 , except that the bubbles introduced into the resin sheet 2 were introduced so as to have the average cell diameter and molten volume shown in Table 1.
[Comparative Example 3]
Ceramic structures were produced in the same manner as in Examples 1 to 5 except that no bubbles were introduced into the resin sheet 2.
[Comparative Example 4]
Ceramic structures were produced in the same manner as in Examples 1 to 5 except that the resin sheet 2a was not fitted.

For each of the ceramic structures of Examples 1 to 7 and Comparative Examples 1 to 5 obtained above, the flatness of the bottom surface and structural defects were evaluated. Each evaluation method is shown below, and the results are also shown in Table 1.
<Evaluation method of flatness of bottom surface>
The flatness of the bottom surface of the concave portion 7 and the cavity 10 is evaluated using a high-speed three-dimensional shape measurement system (“EMS98AD-3D100XY” manufactured by Combs) based on those defined in Japanese Industrial Standards. Average values are shown.
<Evaluation method for structural defects>
The wall surface surrounding the recess 7 or the cavity 10 was observed with a scanning electron microscope for structural defects.

From Table 1, in Examples 1-5 , since pressure lamination was performed in a state in which the resin sheet 2 having a molten state volume V _liq. Of 0.2 V to 0.6 V was fitted, deformation was suppressed and excellent. A ceramic structure with high dimensional accuracy could be obtained. Further, the pressure is applied in a state where the resin sheet 2 containing air bubbles of (1/3) t = 0.5 mm (= 500 μm) or less is fitted to the thickness t = 1.5 mm of the resin sheet having an average diameter. Since the lamination was performed, the flatness was within 30 μm at the bottom surfaces of the recesses 7 and the cavities 10, and a ceramic structure having excellent dimensional accuracy was obtained.

Moreover, in Example 6 , since the resin sheet has a structure in which the resin beads and air bubbles are interposed, the rigidity of the resin sheet itself is improved by the presence of the resin beads that are rigid bodies. However, it was possible to further maintain the uniform pressure lamination and to obtain various results because of the effect of reducing various problems during pyrolysis. Further, in Example 7 , the resin sheet is formed into an upper and lower two-layer structure having different thermal decomposability, and the binder removal process is performed in multiple stages, so that the thermal decomposition of the resin sheet is performed from the upper layer portion to the lowermost layer portion. Since it happened in order, a well-shaped ceramic structure could be obtained.

On the other hand, in Comparative Example 1, the resin sheet 2 having 0.1V lower than 0.2V in the melted state volume V _liq. Is included although it contains bubbles having an average diameter of (1/3) t (= 500 μm) or less _. Since the pressure lamination is performed in a state of being embedded, the void volume (V-V _liq. ) Is increased, and as a result, the resin sheet strength is reduced, so that the pressure equalization lamination becomes difficult. The degree decreased.

In Comparative Example 2, the resin sheet 2 having a molten state volume V _{liq. Of} 0.7 V higher than 0.6 V was fitted, although it included bubbles having an average diameter of (1/3) t (= 500 μm) or less _. Since the pressure lamination was performed in the state, the void volume (V-V _liq. ) Was reduced, making it difficult to release the thermal decomposition gas of the resin sheet to the outside without difficulty. Since cracks occurred in some of the green sheets, the flatness of the bottom surfaces of the recesses 7 and the cavities 10 also decreased.

In Comparative Example 3, since the resin sheet containing no bubbles was used, the molten state volume V _liq. Was practically 1.0 V, and there was no void volume (V-V _liq. ) _. Since it was difficult to release to the outside without difficulty, and cracks occurred in a part of the surrounding green sheet due to the pressure of the pyrolysis gas of the resin sheet, the bottom flatness of the recess 7 and the cavity 10 was also lowered.

  On the other hand, in Comparative Example 4, since the resin sheet 2 was not filled, no pressure was applied to the bottom surfaces of the recesses 7 and the cavities 10 during pressure lamination, and the flatness of the recesses 7 and the cavities 10 was increased.

(A)-(f) is each process drawing explaining the preparation methods of the resin sheet-green sheet composite body by which the resin sheet was engage | inserted by the green sheet in this invention method. (A)-(e) is each process drawing explaining the manufacturing method of the ceramic structure of this invention method.

Explanation of symbols

1: Ceramic green sheet 2, 2a: Resin sheet (black part in the figure indicates resin component, white part indicates bubbles)
2a ': Thermal decomposition melt of resin sheet in the middle of firing process 3: Through hole 4: Upper mold 5: Opening 6: Lower mold 7: Recessed 8: Wiring conductor layer 9: Via conductor 10: Cavity A, A1: Resin Sheet-green sheet composite B1: Ceramic green sheet C: Ceramic green sheet laminate D: Ceramic green sheet laminate during the firing process E: Ceramic structure having recesses on the surface and cavities inside

Claims (8)

When producing a ceramic structure having at least one of a concave portion on the surface and an internal cavity by laminating and firing a plurality of ceramic green sheets,
The void portion serving as the concave portion of the ceramic green sheet having a volume V and the resin sheet having an occupied volume of 0.8 V to 1.1 V in the void portion serving as the cavity (the occupied volume is the volume of bubbles contained inside the resin sheet). Including)
Laminating a plurality of the ceramic green sheets;
A step of thermally decomposing and removing the resin sheet when firing the laminate of the ceramic green sheets,
The resin sheet contains bubbles and satisfies the relationship that the molten state volume V _liq. Immediately before the resin sheet is thermally decomposed is 0.2 V to 0.6 V , and the average diameter of the bubbles is 25 μm or more and 100 μm or less. Yes,
The method for producing a ceramic structure, wherein the resin sheet further includes a resin binder, and the resin binder is isobutyl methacrylate .   The method for producing a ceramic structure according to claim 1, wherein the resin sheet is thermally decomposed at 99% by weight or more at 600 ° C. The resin sheet manufacturing method according to claim 1 or 2, wherein the ceramic structure comprises at least one of the variable plasticizer and lubricants.   The method for producing a ceramic structure according to any one of claims 1 to 3, wherein an average diameter of the bubbles contained in the resin sheet is (1/3) t or less with respect to a thickness t of the resin sheet.   The method for manufacturing a ceramic structure according to claim 1, wherein the resin sheet includes resin beads. In the step of placing the resin sheet on the void portion that becomes the concave portion and the void portion that becomes the cavity of the ceramic green sheet,
Forming a through hole constituting the recess or cavity in the ceramic green sheet;
Inserting a resin sheet into the through-hole to form a resin sheet-green sheet composite;
The method for producing a ceramic structure according to claim 1, further comprising a step of laminating a plurality of the resin sheet-green sheet composites. In the step of removing the resin sheet is thermally decomposed when firing the laminate of the ceramic green sheet, 80% weight reduction temperature T _a ° C. of the upper portion of the resin sheet, 80 of the lowermost portion of the resin sheet When the% weight reduction temperature is T _b ° C and the 20% weight reduction temperature of the resin binder contained in the green sheet on which the resin sheet is placed is T _c ° _C , the relationship of T _a <T _b ≦ T _c is satisfied. The manufacturing method of the ceramic structure in any one of Claims 1-6. A first debinding step of thermally decomposing and removing the upper layer portion of the resin sheet at the T _a ° C, and then a second debinding step of decomposing and removing the lowermost layer portion of the resin sheet at the T _b ° C; The method for producing a ceramic structure according to claim 7, further comprising a third debinding step of thermally decomposing and removing the resin binder contained in the green sheet at a temperature exceeding _Tc ° C.

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