JP2005159256A - Ceramic paste and method of manufacturing ceramic multilayer wiring board using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ceramic paste which has good screen printability and can effectively prevent interlayer adhesion failure as well as bending deformation of the ceramic multilayer wiring board by providing sufficient flowability so as not to deform or break internal wiring lines, and a method of manufacturing a ceramic multilayer wiring board using the same. <P>SOLUTION: In manufacturing a ceramic multilayer wiring board in which a plurality of ceramic layers are laminated and internal wiring lines are formed, ceramic filling layers containing the same ceramic component as that of the ceramic layers are formed between the ceramic layers on regions where internal wiring lines are not formed. For this purpose, the ceramic paste is printed by a screen printing method on portions other than those of the internal wiring lines of green sheets that are to be converted to the ceramic layers on which internal wiring lines are formed. The ceramic paste contains a ceramic component, acrylic resin, and cellulose resin, and its tan δ = (loss modulus)/(storage modulus) in the dry state after the printing is larger than the tan δ in the dry state of the conductive paste which becomes internal wiring lines. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a ceramic paste and a method for manufacturing a ceramic multilayer wiring board having internal wiring using the same, and more particularly, in manufacturing a ceramic multilayer wiring board having a plurality of ceramic layers laminated and having internal wiring. A method for manufacturing a ceramic multilayer wiring board, wherein a ceramic filling layer containing the same ceramic component as a ceramic layer is formed in a region where an internal wiring between ceramic layers laminated with a wiring interposed therebetween is not formed, and the ceramic green having substantially no unevenness The present invention relates to a ceramic paste and a method for producing a ceramic multilayer wiring board, which are suitable for producing a sheet and effectively preventing interlayer adhesion failure and warpage deformation of the ceramic multilayer wiring board.

  Conventionally, a ceramic multilayer wiring board has a structure in which a metallized wiring layer is disposed on or inside an insulating substrate in which a plurality of insulating layers are stacked. A typical example of the ceramic multilayer wiring board having such a structure is a package for housing a semiconductor element that houses a semiconductor element such as an LSI. As such a package for housing a semiconductor element, an insulating layer made of ceramics such as alumina is often used, and more recently, an insulating layer made of a sintered glass-ceramic that can be fired simultaneously with copper metallization is laminated. Those using an insulating substrate have also been put into practical use.

  In the production of such a ceramic multilayer wiring board, a slurry is prepared by adding an appropriate organic binder to a ceramic raw material powder prepared at a predetermined ratio and dispersing it in an organic solvent. A ceramic green sheet (hereinafter also referred to as a green sheet) having a predetermined thickness is formed by a casting method such as a lip coater method.

  Next, as a metallized wiring layer, a metal paste obtained by adding and mixing an organic binder, a solvent, and a plasticizer to an appropriate metal powder is printed and applied to the above green sheet in a pattern with a predetermined shape 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).

Thereafter, a plurality of green sheets are laminated using an appropriate adhesion liquid, and the obtained green sheet laminate is fired under predetermined conditions to obtain a ceramic multilayer wiring board.
JP-A-5-3273 JP-A-11-97272

  In the conventional ceramic multilayer wiring substrate (hereinafter also referred to as a substrate) as described above, the substrate tends to be reduced in size and thickness as the functionality and functionality are increased. Furthermore, miniaturization of wiring patterns and via holes formed on a substrate is progressing, and improvement in stacking accuracy is desired. In particular, in ceramic multilayer wiring boards that are becoming thinner, voids caused by differences in height due to the thickness of the internal wiring that occurs when the internal wiring is formed are completely eliminated by only plastic deformation of the thin green sheet during lamination. It is difficult. As a result, there has been a problem in that the product after firing has poor interlayer adhesion, so-called delamination and warpage deformation.

  As a means for solving this problem, a ceramic filling layer containing the same ceramic component as the ceramic layer is formed by screen printing in a region where the internal wiring between the ceramic layers laminated with the internal wiring interposed therebetween is not formed. .

  However, the green sheet having the ceramic filling layer obtained by the screen printing method has a problem that the pattern edge portion is raised by the surface tension when the screen is separated, or when the pattern is made into a fine line and a thick film. Since a phenomenon that swells in a substantially semicircular or semi-elliptical shape occurs, it is difficult to completely remove the unevenness on the surface, and it is necessary to add a step of pressure flattening with a flat press or the like.

  As the binder of the ceramic paste used in the screen printing method, a cellulose-based binder that is generally excellent in printability is often used. However, since the ceramic paste using the cellulose binder is inferior in fluidity, it is difficult to sufficiently flatten it in the above-described pressure flattening step. Therefore, an attempt to add an acrylic binder for the purpose of giving flexibility to the cellulose-based binder of the ceramic paste, or adding a plasticizer such as phthalate ester or a solvent with a high boiling point to improve fluidity Generally done.

  However, if the balance of the viscoelasticity of the ceramic paste is not properly controlled, if pressure flattening is performed under a temperature condition equal to or higher than the glass transition temperature of the acrylic binder added to the ceramic paste, It is difficult to planarize adjacent internal wiring patterns without deforming them. That is, tan δ = (loss elastic modulus) / (storage elastic modulus) in the dry state of the ceramic paste near the heating temperature in the pressure planarization step is larger than tan δ in the dry state of the conductor paste layer serving as the internal wiring. If it is small, the internal wiring is greatly deformed when stress is applied from the ceramic paste side where the elastic behavior is more dominant to the internal wiring layer side where the viscous behavior is more dominant. It becomes easy.

  Therefore, the elastic behavior seems to be dominant by simply increasing only the elastic modulus of the ceramic paste with respect to the internal wiring, in other words, by lowering the tan δ in the dry state of the ceramic paste with respect to the internal wiring. It is difficult to protect the adjacent internal wiring from deformation during pressurization by providing a means for forming a strong ceramic paste layer.

  On the other hand, when an acrylic binder whose molecular weight is not adjusted appropriately is used, the spinnability, which is a defect of the acrylic binder during screen printing, often becomes a problem.

  In addition, when an excessive amount of plasticizer or solvent is used, the viscosity of the ceramic paste tends to increase due to poor drying even if the drying process is performed after screen printing. In some cases, the strength of the print is low, and there is a problem that the printed matter is transferred to the press surface due to cohesive failure or interfacial failure during the pressure flattening step.

  Therefore, the present invention has been completed in view of the above-mentioned problems, and its purpose is to use a ceramic paste that has good screen printability and an appropriate viscoelastic balance with respect to internal wiring. Full flow without increasing the amount of plasticizer and solvent by filling the area where the internal wiring is not formed and performing the subsequent pressure flattening process under the heating condition above the glass transition temperature of the acrylic binder in the ceramic paste. Manufacturing of ceramic paste and ceramic multilayer wiring board using the same, which can more effectively prevent interlaminar adhesion failure and warpage deformation of ceramic multilayer wiring board because it does not deform internal wiring Is to provide a method.

  The ceramic paste of the present invention has a ceramic layer in a region where internal wiring between ceramic layers laminated with internal wiring is not formed when a ceramic multilayer wiring board having a plurality of ceramic layers stacked and having internal wiring is formed. A ceramic paste printed by a screen printing method on a portion of the ceramic green sheet other than the internal wiring of the ceramic green sheet that forms the ceramic layer on which the internal wiring is formed to form a ceramic filling layer containing the same ceramic component Contains a ceramic component, an acrylic resin and a cellulose resin, and tan δ expressed by (loss elastic modulus) / (storage elastic modulus) in a dry state after printing is a dry state of the conductor paste layer serving as an internal wiring It is characterized by being not less than tan δ.

  The ceramic paste of the present invention is preferably characterized in that the acrylic resin has a glass transition temperature of 20 to 50 ° C.

  In the ceramic paste of the present invention, preferably, the acrylic resin has a molecular weight of 40,000 to 60,000.

  The ceramic paste of the present invention is preferably characterized in that the cellulose resin contains at least one of nitrocellulose and ethylcellulose.

  The method for manufacturing a ceramic multilayer wiring board according to the present invention includes: a plurality of ceramic layers laminated and a ceramic multilayer wiring board having an internal wiring; A method for manufacturing a ceramic multilayer wiring board, wherein a ceramic filling layer containing the same ceramic component as the ceramic layer is formed in a region where no wiring is formed, wherein the interior of the ceramic green sheet serving as the ceramic layer in which the internal wiring is formed It contains the ceramic component, acrylic resin, and cellulose resin in a portion other than the conductive paste layer that becomes the wiring, and is expressed by (loss elastic modulus) / (storage elastic modulus) in a dry state after screen printing. A ceramic sheet whose tan δ is equal to or greater than tan δ in the dry state of the conductor paste layer. A paste is printed by a screen printing method to form a ceramic paste layer, and after the ceramic paste layer is dried, the ceramic paste layer is pressed and plastically deformed at a temperature equal to or higher than the glass transition temperature of the acrylic resin. A ceramic green sheet laminate is produced by flattening the surface and then laminating the ceramic green sheet on which the ceramic paste layer is formed and another ceramic green sheet, and then firing the ceramic green sheet laminate. It is characterized by that.

  The method for producing a ceramic multilayer wiring board according to the present invention is preferably characterized by pressurizing the ceramic paste layer at a temperature of 50 to 80 ° C.

  Since the ceramic paste of the present invention contains a ceramic component, an acrylic resin, and a cellulose resin, the ceramic paste can be used without increasing the amount of binder in the ceramic paste by utilizing the flexibility of the acrylic resin and using the cellulose resin. The paste can be made highly viscous and thixotropic, and the screen printability can be improved.

  Further, since the ceramic paste has a tan δ represented by (loss elastic modulus) / (storage elastic modulus) in a dry state after printing, it is not less than tan δ in a dry state of the conductor paste layer serving as an internal wiring. By flowing the ceramic paste layer side where the viscous behavior is more dominant at the time of pressurization, it is possible to prevent deformation of the internal wiring side where the adjacent elastic behavior is more dominant. In addition, since unnecessary elastic stress is not applied from the ceramic paste layer side to the internal wiring side, it is possible to prevent the internal wiring from being damaged such as cracks. As a result, it is possible to prevent the damaged conductor paste layer from adhering to the press surface during the flattening step and peeling off. That is, by using the ceramic paste of the present invention, it is possible to prevent deformation and breakage of internal wiring, and as a result, a flat ceramic layer having no defects can be formed. In the wiring board, it is possible to more effectively prevent interlayer adhesion failure and warpage deformation.

  In the ceramic paste of the present invention, the acrylic resin preferably has a glass transition temperature of 20 to 50 ° C., so that the temperature is not lower than the glass transition temperature and the entire ceramic multilayer wiring board is not deformed. By performing pressure flattening at 0 ° C., the fluidity is developed on the ceramic paste side without increasing the amount of plasticizer or solvent, thereby preventing deformation on the internal wiring side.

  In the ceramic paste of the present invention, preferably, the acrylic resin has a molecular weight of 40,000 to 60,000, so that the spinnability of the ceramic paste can be reduced.

  In the ceramic paste of the present invention, preferably, the cellulose resin contains at least one of nitrocellulose and ethylcellulose, thereby improving the printability and the like. That is, it has the effect of compensating for various problems such as the viscosity of the paste and insufficient thixotropy, the problem of spinnability at the time of printing and the insufficient film strength of the printed matter, which are disadvantages of the acrylic resin.

  According to the method for manufacturing a ceramic multilayer wiring board of the present invention, when manufacturing a ceramic multilayer wiring board having a plurality of ceramic layers laminated and having internal wiring, the internal wiring between the ceramic layers stacked with the internal wiring interposed therebetween is formed. A method for manufacturing a ceramic multilayer wiring board in which a ceramic filling layer containing the same ceramic component as a ceramic layer is formed in a region that is not formed, except for a conductive paste layer that is an internal wiring of a ceramic green sheet that is a ceramic layer on which an internal wiring is formed Tanδ represented by (loss elastic modulus) / (storage elastic modulus) in a dry state after screen printing is contained in the portion of the ceramic paste, acrylic resin and cellulose resin, and the dry state of the conductor paste layer Print ceramic paste with tan δ or more by screen printing method To form a ceramic paste layer, and after drying the ceramic paste layer, the ceramic paste layer is pressed and plastically deformed at a temperature equal to or higher than the glass transition temperature of the acrylic resin to flatten the surface, and then the ceramic paste layer A ceramic green sheet laminate is produced by laminating ceramic green sheets formed with other ceramic green sheets, and then firing the ceramic green sheet laminate to make it more viscous during the pressure flattening process. When the ceramic paste layer side where the behavior is dominant flows, deformation of the adjacent internal wiring side can be prevented. In addition, since unnecessary elastic stress is not applied from the ceramic paste layer side to the internal wiring side, it is possible to prevent the internal wiring from being damaged such as cracks. As a result, it is possible to prevent the damaged conductor paste layer from adhering to the press surface during the flattening step and peeling off. That is, the method for manufacturing a ceramic multilayer wiring board according to the present invention can prevent deformation and breakage of internal wiring, and as a result, a flat ceramic layer having no defects can be obtained. In the multilayer wiring board, it is possible to more effectively prevent interlayer adhesion failure and warpage deformation.

  The ceramic paste of the present invention and a method for producing a ceramic multilayer wiring board using the same will be described in detail below.

  First, a green sheet for producing a ceramic multilayer wiring board is produced as follows. Green powder powder, for example, ceramic powder or glass powder is added to ceramic powder as a sintering aid if necessary, and the mixture is mixed with additives such as binder and plasticizer, organic solvent, etc. In addition, a slurry is prepared. 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, by punching the green sheet, a through hole serving as a via hole connecting the upper and lower wiring conductor layers is formed, and a conductor paste is filled in the through hole.

The ceramic powder includes SiO ₂ , Al ₂ O ₃ , ZrO ₂ , a composite oxide of 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 Composite oxidation containing at least one selected from 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 Al ₂ O ₃ and SiO ₂ (For example, spinel, mullite, cordierite) and the like, and can be selected according to 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 are also amorphous glass by firing, and by firing, lithium silicate, quartz, cristobalite, cordierite, mullite, anorthite, serdian, spinel, garnite, willemite, dolomite, petalite and Crystallized glass that precipitates at least one kind of crystals of the substituted derivative is used.

  The mixing ratio of the ceramic powder and the glass powder is a ratio used for a normal glass ceramic substrate 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.

Furthermore, as a binder, what is generally used for the green sheet can be used, for example, acrylic (a homopolymer or copolymer of acrylic acid, methacrylic acid or an ester thereof, specifically acrylic acid. Ester copolymer, methacrylate ester copolymer, acrylic ester-methacrylic ester copolymer, etc.), polyvinyl butyral, polyvinyl alcohol, acrylic-styrene, polypropylene carbonate, cellulose, or other homopolymers or A copolymer is mentioned.

  Next, the conductor paste for forming the metallized wiring layer is not particularly limited, and examples thereof include one or more metal powders such as Au, Cu, Ag, Pd, W, and Pt. In this case, it may be in any form such as mixed, alloyed, or a multi-layer coating formed individually. A mixture of these metal powders with a binder made of an acrylic resin, an organic solvent such as toluene, isopropyl alcohol, acetone, terpineol, and a plasticizer can be suitably used. The binder is preferably mixed in an amount 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 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.

  When manufacturing a ceramic multilayer wiring board formed by laminating a plurality of ceramic layers and having internal wiring, a ceramic containing the same ceramic component as the ceramic layer in a region where the internal wiring between the ceramic layers stacked with the internal wiring interposed therebetween is not formed The packed layer is formed by a screen printing method, and then the printed surface is dried in a hot air drying furnace or a far infrared drying furnace. The obtained ceramic green sheet is subjected to a pressure flattening step under heating conditions of 50 to 80 ° C., so that the ceramic filling layer is plastically deformed and flattened to obtain a ceramic green sheet substantially free of unevenness.

  Then, an appropriate adhesive composed of a binder, a solvent, and a plasticizer is applied to or transferred to the green sheet and integrated with other green sheets by pressure lamination to produce a green sheet laminate. A ceramic multilayer wiring board can be obtained by firing the obtained green sheet laminate under predetermined conditions.

  Next, the ceramic paste used for the ceramic multilayer wiring board of the present invention and the method for producing the ceramic multilayer wiring board using the same will be described in detail.

The ceramic material contained in the ceramic paste is basically the same ceramic as the ceramic multilayer wiring board. Accordingly, the ceramic powder includes SiO ₂ , Al ₂ O ₃ , ZrO ₂ , a composite oxide of 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 Composite oxidation containing at least one selected from 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 Al ₂ O ₃ and SiO ₂ (For example, spinel, mullite, cordierite) and the like, and can be selected according to 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 are also amorphous glass by firing, and by firing, lithium silicate, quartz, cristobalite, cordierite, mullite, anorthite, serdian, spinel, garnite, willemite, dolomite, petalite and Crystallized glass in which at least one kind of crystals of the substituted derivative is precipitated is used.

  The mixing ratio of the ceramic powder and the glass powder is a ratio used for a normal glass ceramic substrate 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.

  Furthermore, the binder of the ceramic paste of the present invention contains an acrylic resin and a cellulose resin as essential components, and the balance of viscoelasticity to the internal wiring is achieved by controlling the blending balance, glass transition temperature and molecular weight of the acrylic resin, and the like. I have control.

  Here, when only an acrylic resin is used as the binder, it is difficult to increase the viscosity and thixotropy of the ceramic paste. Therefore, it is necessary to improve the viscosity and thixotropy by increasing the amount of binder and decreasing the amount of solvent. However, in this case, there is a problem that the spinnability increases during screen printing and the separation property of the plate (screen printing plate) deteriorates. Further, when the amount of the binder is increased, the density of the sintered body after firing is reduced, which causes a void. Further, when the amount of the solvent is reduced, there is a problem that the fluidity of the ceramic paste is lowered.

  On the other hand, when only a cellulose resin is used as the binder, the fluidity of the ceramic paste is inferior, so that it is difficult to sufficiently planarize in the pressure planarization step. Furthermore, the cellulose resin alone has a low tan δ in the dry state, in other words, the elastic behavior tends to dominate the viscous behavior, and the tan δ in the dry state is controlled higher than the internal wiring. It becomes difficult.

  From these viewpoints, the present invention can solve the above-mentioned problems by preparing an acrylic resin and a cellulose resin as essential components and preparing a ceramic paste while controlling the composition and properties of the acrylic resin.

  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. In these copolymers, 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. 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.

  The glass transition temperature of the acrylic resin of the ceramic paste of the present invention needs to be adjusted to 20 to 50 ° C, and more preferably 20 to 30 ° C. Glass transition temperature of acrylic resin containing acrylic resin and printed matter that has been dried in a hot air drying furnace or far infrared drying furnace after screen printing ceramic paste with increased tan δ in the dry state with respect to internal wiring By pressurizing under the above heating conditions, the ceramic paste layer can have fluidity and an excellent flatness can be realized during the flattening step without increasing the amount of plasticizer and solvent.

  If the glass transition temperature of the acrylic resin is less than 20 ° C., the printed matter may remain sticky even after the drying process after screen printing, and the printed matter aggregates during the subsequent pressure flattening step under heating conditions. It tends to be transferred (attached) to the press surface by being broken or interfacial broken.

  In addition, in the pressure flattening step under heating conditions, in order to prevent transfer (adhesion) of the printed material to the press surface, the press surface may be subjected to a peeling treatment such as fluorine treatment or silicone treatment, or the printed material and the press surface. It is desirable to provide a means for interposing a resin sheet such as PET subjected to a release treatment of silicone, wax or the like.

  When the glass transition temperature of the acrylic resin exceeds 50 ° C., the fluidity of the printed matter tends to be poor when the pressure flattening step is performed at 80 ° C. or less, which is a temperature range in which the entire ceramic multilayer wiring board is not deformed. It is in.

  From the above viewpoints, the glass transition temperature of the acrylic resin used for the ceramic paste is set to 20 to 50 ° C., and by using the cellulose resin together, the screen printing property is excellent, and the pressure flatness following the subsequent drying step In the crystallization process, by making tan δ in the dry state of the ceramic paste in the temperature range where the entire ceramic multilayer wiring board is not deformed to be tan δ or more under the same conditions of the adjacent internal wiring, more viscous behavior can be obtained. It has been found that the dominant ceramic paste layer is selectively deformed and flattened and does not apply a large stress to the adjacent internal wiring, thereby preventing deformation and breakage of the internal wiring.

  Specifically, for example, when tan δ in the dry state of the ceramic paste at 60 ° C. is controlled to be equal to or higher than tan δ under the same conditions of the adjacent internal wiring, the temperature condition of the subsequent pressure planarization step is set to 50. By setting the temperature to ˜80 ° C., the ceramic paste after printing can have sufficient fluidity without increasing the amount of plasticizer and solvent, and deformation and breakage of the internal wiring can be prevented.

  Here, when the temperature condition of the pressure planarization step is set to a temperature of less than 50 ° C., the ceramic layer may not be sufficiently planarized. On the other hand, when performed at a temperature exceeding 80 ° C., the ceramic layer is deformed. It is not preferable because it tends to receive.

  Moreover, it is necessary to adjust the molecular weight of the acrylic resin used for a ceramic paste to 40000-60000, and it becomes possible to reduce the stringiness of a ceramic paste by limiting to this range. When the molecular weight is less than 40,000, it is difficult to increase the viscosity of the ceramic paste and the screen printing property is deteriorated, and the strength of the filling after printing tends to be insufficient. On the other hand, when the molecular weight exceeds 60,000, the spinnability of the ceramic paste becomes remarkable, and the screen printability tends to deteriorate, for example, the plate separation property at the time of printing deteriorates.

  As the cellulose resin, at least one of nitrocellulose (nitrified cotton) and ethyl cellulose suitable for screen printing can be used.

  These acrylic resin and cellulose resin can be mixed and used at an arbitrary ratio as long as they are dissolved in a solvent and compatible with each other. However, the total amount of acrylic resin and cellulose resin mixed is 100% by weight. The acrylic resin is preferably about 20 to 90% by weight, more preferably 50 to 90% by weight. When the acrylic resin is less than 20% by weight, the tan δ in the dry state is increased with respect to the internal wiring, in other words, the viscous behavior is more dominant than the elastic behavior, and the pressure flattening process under the heating condition is performed. It becomes difficult to obtain sufficient fluidity without deforming the internal wiring. If it exceeds 90% by weight, the thixotropy of the ceramic paste during screen printing tends to be insufficient.

  The solvent used in the ceramic paste of the present invention can be selected from a high boiling point solvent group generally used for screen printing. Specifically, those having a boiling point of 150 ° C. or higher are preferable, and those having a boiling point of about 200 to 250 ° C. are more preferable. When the temperature is lower than 150 ° C., the solvent volatilizes during screen printing or the like, and problems such as clogging of the screen mesh are likely to occur. On the other hand, at 250 ° C. or higher, it becomes difficult to sufficiently dry the printed matter, and the printed matter that is insufficiently dried tends to be transferred to the press surface in the pressure flattening step under heating conditions.

  Furthermore, it is preferable to select a solvent that dissolves both the acrylic resin and the cellulose resin that are the binder of the present invention. What satisfies these conditions includes a mixed solvent of terpineol and butyl carbitol acetate, and the like.

  In general, paste for screen printing generally has a resin content of about 1 to 30 parts by weight with respect to 100 parts by weight of various ceramic powders, but the optimum mixing ratio varies depending on the specific gravity of the ceramic powder. However, it is not limited to this range.

  The ceramic paste of the present invention is composed of various ceramic powders, binders made of acrylic resin and cellulose resin, a solvent, a plasticizer, a lubricant, a dispersant, and the like. Furthermore, you may add various thixotropic agents, thickeners, etc. as needed.

  The plasticizer is not particularly limited. Phthalates such as butyl phthalyl butyl glycolate, aliphatic esters such as di-2-ethylhexyl adipate and dibutyl diglycol adipate, trimellitic acids such as trimellitic acid tri-2-ethylhexyl, etc. And contains at least one selected from these. Among them, plasticizers such as phthalic acid esters such as dibutyl phthalate (DBP) and di-2-ethylhexyl phthalate (DOP) are preferable.

  The lubricant is not particularly limited. 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 Ethylene glycols such as ether, ethylene glycol-n-acetate, diethylene glycol monohexyl ether, diethylene glycol monovinyl ether, dipropylene glycol, tripropylene glycol, polypropylene glycol, dipropylene glycol methyl ether, tripropylene glycol methyl ether, dipropylene glycol mono D Ether, dipropylene glycol-n-butyl ether, tripropylene glycol-n-butyl ether, propylene glycol phenyl ether, ethylene glycol benzyl ether, ethylene glycol isoamyl ether and other propylene glycol systems, glycerin, diglycerin, glycerin systems such as polyglycerin, Natural wax systems such as beeswax and wax, paraffin wax, microcrystalline wax, synthetic wax systems such as low molecular weight polyethylene and its derivatives, fatty acid systems such as stearic acid and lauric acid, fatty acid amides such as maleic acid imide and stearic acid amide And fatty acid metal salt systems such as aluminum stearate, magnesium stearate and calcium stearate. It contains at least one. Of these, polyethylene glycol (PEG) and glycerin are preferable.

  Examples of the method for producing a ceramic paste and a ceramic multilayer wiring board according to the present invention will be described below.

[Measurement of tan δ]
A rheology measuring device (model: MCR300, manufactured by PHYSICA) was used for the measurement of tan δ represented by (loss elastic modulus) / (storage elastic modulus) shown in this example. The ceramic paste and the conductor paste serving as the internal wiring were each printed with a screen printer so as to form a sheet having a thickness of 100 μm, and then dried at 80 ° C. for 1 hour using a warm air drying furnace. A sheet-like sample having a thickness of 0.5 mm and a diameter of 20 mm is produced by setting the dried sheet-like material in a mold of a press molding machine and pressurizing with a pressure of 4.9 × 106 Pa. And used as a measurement sample.

  Then, the strain changed by sweeping from 0 to 100% at a frequency of 100 Hz was given to the measurement sample under a constant temperature condition of 60 ° C., and the storage elastic modulus and the loss elastic modulus were measured. When such a sinusoidal distortion is applied to the elastic body, the viscous body is distorted in the same phase, but the phase of the viscous body is shifted by 90 degrees. Therefore, the ceramic paste and the conductive paste, which are intermediate viscoelastic bodies, are applied. The phase shifts from 0 to 90 degrees with respect to the distortion. Using this fact, tan δ = (loss elastic modulus) / (storage elastic modulus) was obtained. When tan δ was measured with the composition of the conductor paste described later, it was 0.5.

(Examples 1 to 10)
A slurry is prepared by adding an alumina-based ceramic powder containing alumina as a main component, an additive such as a binder and a plasticizer, and an organic solvent. The slurry is molded by a doctor blade method and dried to a length of 50 mm. A green sheet having a size of 50 mm in width and 0.3 mm in thickness was produced.

  Next, 5 parts by weight of a binder having a composition ratio shown in Table 1 below and 20 parts by weight of a mixed solvent of terpineol and butyl carbitol acetate with respect to 100 parts by weight of the alumina-based ceramic mixed powder mainly composed of alumina, 20 parts by weight of a phthalate ester plasticizer (mixture of DOP and DBP) was added, and these were stirred and mixed. Thereafter, a ceramic paste was prepared by mixing with a three-roll mill until there was no aggregate of ceramic powder and binders.

  On the other hand, with respect to 100 parts by weight of tungsten powder, 1.5 parts by weight of a binder having a composition ratio of acrylic resin and nitrocellulose of 3: 2, 5 parts by weight of a mixed solvent of terpineol and butyl carbitol acetate, and a phthalate ester 5 parts by weight of a plasticizer (mixture of DOP and DBP) was added and mixed, and these were stirred and mixed thoroughly. The acrylic resin used had a glass transition temperature of 50 ° C. and a molecular weight of 50000. Then, it mixed with the 3 roll mill until the aggregate of tungsten powder and resin was lost, and the conductor paste for metallized wiring was prepared.

  Furthermore, using this conductor paste, a wiring pattern having a height (thickness) of 15 μm is printed and applied to the main surface of the green sheet by a screen printing method, followed by drying at 80 ° C. for 1 hour using a warm air drying oven. Forming a metallized wiring, forming a ceramic filling layer by screen printing using the above ceramic paste in a region where the metallized wiring is not formed, and then drying at 80 ° C. for 1 hour using a hot air drying oven, Was made.

  Table 1 shows the presence / absence of spinnability and screen release properties, which are screen printing characteristics when these various ceramic pastes are used, as ○ (good), Δ (slightly good), and × (bad). Further, Table 1 shows the value of tan δ in a dry state separately measured by a rheology measuring apparatus.

  Subsequently, using a flat press machine with a PET (polyethylene terephthalate) film subjected to silicone peeling treatment, the printed surfaces of the two ceramic green sheets obtained were heated under the heating temperature conditions shown in Table 1. The ceramic filling layer was plastically deformed by pressurizing at a pressure of .9 × 10 6 Pa, and flattened. At this time, it was visually confirmed whether or not the printed matter was transferred to the PET peeled surface by cohesive failure or the like.

  Subsequently, by pressing and laminating a green sheet coated with an adhesive composed of an acrylic resin, a solvent, and a phthalate ester plasticizer, the five green sheets were integrated to form a green sheet laminate having internal wiring. Produced.

  Finally, the green sheet laminate was fired at around 1600 ° C. to obtain a ceramic multilayer wiring board. The obtained ceramic multilayer wiring board was measured with a high-speed three-dimensional shape measurement system (model: EMS98AD-3D100XY, manufactured by Combs), and the maximum height difference was listed in Table 1 as the maximum warpage value. Also, the presence or absence of interlayer adhesion failure was observed in an enlarged manner and shown in Table 1.

(Comparative Examples 1-9)
Ceramic multilayer wiring boards were produced in the same manner as in Examples 1 to 10, except that the binder components of the ceramic paste and the heating temperature conditions in Examples 1 to 10 were those in Comparative Examples 1 to 9 in Table 1.

  From Table 1, in the ceramic multilayer wiring board manufactured by the manufacturing method of the present invention using the ceramic pastes of Examples 1 to 10, the screen-printing properties, which are stringiness and release properties, are good and the printed matter is dried. Since each tan δ in the state is higher than tan δ = 0.5 of the internal wiring, it is possible to realize excellent flatness without deforming and damaging the internal wiring. It was possible to prevent the occurrence more effectively.

  Furthermore, since it planarizes on the heating temperature conditions of 50 to 80 degreeC, the curvature and the interlayer adhesion defect could also be prevented.

  Furthermore, it was possible to prevent defects such as the printed matter being transferred to the PET film peeling surface due to cohesive failure or the like.

  On the other hand, in Comparative Example 1, since the glass transition temperature of the acrylic resin used for the ceramic filling layer was as low as 10 ° C., the tackiness was strong and the spinnability became remarkable at the time of screen printing and the release property was slightly lowered. . Moreover, since the printed matter after drying was also sticky, a defect in which a part of the printed matter was transferred to the silicone release surface of the PET film during the pressure flattening step was observed.

  In Comparative Example 2, since the glass transition temperature of the acrylic resin used for the ceramic filling layer is as high as 60 ° C., the tan δ in the dry state in the temperature region where the entire ceramic multilayer wiring board is not deformed during pressurization is higher than the internal wiring. Since it was low and poor in fluidity, it could not be completely flattened, the warp value of the product was large, and interlayer adhesion failure was also observed.

  In Comparative Example 3, since the heating temperature in the pressure planarization process was as low as 40 ° C., it was not possible to completely planarize, and the warpage value of the product was large and the interlayer adhesion was poor.

  In Comparative Example 4, since the heating temperature in the pressure flattening step is as high as 90 ° C., the printed material softened during pressurization and the strength was reduced. Therefore, a part of the printed material was transferred to the silicone release surface of the PET film. The defect was seen. Further, since the entire ceramic multilayer wiring board was subjected to pressure deformation, the warpage of the product also increased.

  In Comparative Example 5, since only the acrylic resin was used for the ceramic filling layer, the viscosity and thixotropy of the printing paste were low, and the screen printability was deteriorated. Furthermore, since the film strength of the printed material was low, a defect in which a part of the printed material was transferred to the silicone release surface of the PET film during the pressure flattening process was observed.

  In Comparative Examples 6 and 7, since only nitrocellulose or ethylcellulose was used for the ceramic packed layer, tan δ of the printed material in a dry state was low, and the elastic behavior was dominant, so that it was difficult to completely flatten it. Also, since tan δ is low with respect to the internal wiring, the internal wiring is stressed and deformed during the pressure flattening process, so that the warpage value of the product is large and the interlayer adhesion is also defective.

  In Comparative Example 8, since the molecular weight of the acrylic resin used for the ceramic filling layer was as low as 30000, the viscosity of the printing paste was low. Furthermore, since the film strength of the printed material was low, a defect in which a part of the printed material was transferred to the silicone release surface of the PET film during the pressure flattening process was observed.

  In Comparative Example 9, since the molecular weight of the acrylic resin used for the ceramic packed layer was as high as 70000, the spinnability became remarkable during screen printing and the plate release property was lowered.

Claims (6)

When manufacturing a ceramic multilayer wiring board formed by laminating a plurality of ceramic layers and having internal wiring, the same ceramic as the ceramic layer is formed in a region where the internal wiring between the ceramic layers stacked with the internal wiring interposed therebetween is not formed A ceramic paste printed by a screen printing method on a portion other than the internal wiring of a ceramic green sheet to be the ceramic layer on which the internal wiring is formed in order to form a ceramic filling layer containing components, The paste contains the ceramic component, acrylic resin and cellulose resin, and tan δ expressed by (loss elastic modulus) / (storage elastic modulus) in a dry state after printing is a conductor paste layer serving as the internal wiring Ceramics characterized by being tan δ or more in the dry state of Kupaste. The ceramic paste according to claim 1, wherein the acrylic resin has a glass transition temperature of 20 to 50C. The ceramic paste according to claim 1 or 2, wherein the acrylic resin has a molecular weight of 40,000 to 60,000. The ceramic paste according to any one of claims 1 to 3, wherein the cellulose resin contains at least one of nitrocellulose and ethylcellulose. When manufacturing a ceramic multilayer wiring board formed by laminating a plurality of ceramic layers and having internal wiring, the same ceramic as the ceramic layer is formed in a region where the internal wiring between the ceramic layers stacked with the internal wiring interposed therebetween is not formed A method for producing a ceramic multilayer wiring board for forming a ceramic-filled layer containing a component, wherein the ceramic green sheet to be the ceramic layer on which the internal wiring is formed, in a portion other than the conductor paste layer to be the internal wiring, Tan δ, which includes a ceramic component, an acrylic resin, and a cellulose resin, and is expressed by (loss elastic modulus) / (storage elastic modulus) in a dry state after screen printing is tan δ in the dry state of the conductive paste layer. Print the ceramic paste as described above by screen printing. After the ceramic paste layer is dried, the ceramic paste layer is pressed and plastically deformed at a temperature equal to or higher than the glass transition temperature of the acrylic resin to flatten the surface, and then the ceramic A ceramic multilayer wiring board characterized in that a ceramic green sheet laminate is produced by laminating the ceramic green sheet on which a paste layer is formed and another ceramic green sheet, and then firing the ceramic green sheet laminate. Manufacturing method. 6. The method for producing a ceramic multilayer wiring board according to claim 5, wherein the ceramic paste layer is pressurized at a temperature of 50 to 80 [deg.] C. when the ceramic paste layer is pressurized.