JP2010045209A - Method of manufacturing laminated ceramic electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a laminated ceramic electronic component which can obtain reliable conduction between each veer electrode and each internal electrode by preventing the formation of clearances between each dielectric layer and each veer electrode while effectively preventing the occurrence of structural defects of the dielectric layers. <P>SOLUTION: A laminated ceramic capacitor 1 has the dielectric layers 11 and the internal electrodes 12 which are alternately laminated, where the internal electrodes 12 arranged opposing each other via the dielectric layers 11 are connected to each other via the veer electrodes 14. Its manufacturing method comprises steps for forming veer holes in a ceramic green sheet for the dielectric layers 11 and a conductive paste laminate for the internal electrodes 12 and firing them to obtain a laminate in which the dielectric layers 11 and the internal electrodes 12 are formed, and then filling conductive paste for the veer electrodes 14 in the veer holes of the laminate and further applying baking treatment thereto to form the veer electrodes 14. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a multilayer ceramic electronic component.

  In recent years, there has been a demand for further downsizing, thinning, and high-density mounting of electronic devices. Active components such as semiconductor devices such as IC chips used in electronic devices, and passive components such as capacitors, inductors, thermistors, resistors, etc. Similarly, miniaturization and thinning of circuit boards on which electronic components such as these are mounted are also eagerly desired.

  Among these electronic components, especially for ceramic chip capacitors that are multilayer (type) ceramic electronic components, there is a strong demand from the market not only for miniaturization and thinning, but also for higher capacities. . On the other hand, in order to meet the demand for high-density mounting, the mounting area of electronic components cannot be increased, so in ceramic chip capacitors, the dielectric and internal electrodes are rapidly becoming thinner. For example, even in the C2012 size (outer dimensions 2.0 mm × 1.2 mm × 1.2 mm), the number of stacked layers exceeding 800 layers is on the market. In addition, there is a tendency to reduce the mounting area of the electronic component on the circuit board. To cope with this, for example, external connection pads are not connected to the side wall of the main body, but external connection pads are connected to the upper wall surface and the lower wall surface. Surface mount multilayer ceramic capacitors have been developed that have external terminals and terminals and are externally connected from both sides in the stacking direction.

As such a type of multilayer ceramic electronic component, for example, in Patent Document 1, a plurality of dielectric layers are stacked, and an internal electrode made of a sintered body of a conductive material containing Ni particles is formed between the layers. Further, there has been proposed a multilayer ceramic electronic component (capacitor) provided with a via conductor made of a sintered body of a conductive material containing Ni particles and Cu particles so as to connect internal electrodes. Also in Patent Document 2, a multilayer ceramic electronic component having the same configuration, that is, a dielectric ceramic layer and an internal wiring pattern are alternately stacked, and a wiring pattern that is spaced apart and facing through the dielectric ceramic layer is a dielectric. What is connected by a via electrode penetrating the ceramic layer is described.
JP 2005-136231 A JP 2003-151851 A

  By the way, according to Patent Documents 1 and 2, in order to manufacture the above conventional multilayer ceramic electronic component, a plurality of ceramic green sheets for forming dielectric layers and conductor material layers for forming internal electrodes are alternately stacked. After obtaining a body, a via hole (through hole) for forming a via electrode (via conductor) is formed in the laminated body, and a conductive paste for forming a via electrode is embedded in the via hole (via fill) (Patent Document) 1 (see FIG. 17 of Patent Document 2), or whenever a ceramic green sheet and a conductor material layer are laminated, a via hole is formed and a conductive paste for forming a via electrode is filled, After forming the laminated body by repeating the process (single-wafer type; see FIG. 1 of Patent Document 2), both use the method of firing the whole at the same time. Internal electrodes provided in the dielectric layers, and the between the internal electrodes is described that the laminated ceramic electronic part connected by via electrodes can be obtained.

However, when the present inventor has examined the manufacturing method in detail, for example, when a conductor material for forming a via electrode containing Cu is used, a temperature required for firing the ceramic green sheet (for example, BaTiO _3). In the case of a ceramic, the melting point of Cu (1100 ° C. or higher) is higher than the melting point of Cu (1083 ° C.). did. At this time, even if the conductor material for forming the via electrode contains Ni (melting point: 1453 ° C.) or the like having a melting point higher than the firing temperature in addition to Cu, Ni is also melted together with the melting of Cu. In other words, it was also confirmed that a via electrode conductor could not be formed. In both Patent Documents 1 and 2, a multilayer ceramic electronic component in which a via electrode is formed is actually manufactured by a manufacturing method in which Cu is used as a conductive material for a via electrode and the above-described simultaneous firing is performed. There is no description of examples showing what could be done.

  Further, since the ceramic green sheet and the conductor material for forming the internal electrode and the via electrode are fired simultaneously, the firing temperature becomes a high temperature necessary for sintering the ceramic green sheet as described above. However, the difference in the degree of expansion and contraction between the ceramic green sheet and the conductor material layer having different thermal expansion coefficients becomes very large. As a result, a gap is likely to be formed between the dielectric layer formed after firing and the via electrode, which makes it difficult to reliably conduct (electrically connect) the via electrode and the internal electrode. Furthermore, the ceramic green sheet and the conductor material layer are usually debindered at a relatively low temperature before firing and become relatively brittle. In such a state, the conductor layer for forming the internal electrode and the via electrode is heated at a high temperature. When co-fired, the difference in relative expansion and contraction behavior with those conductor materials becomes large, resulting in cracks in the dielectric layer and delamination between layers. In addition, there is a disadvantage that structural defects such as or are likely to occur. In particular, in the present situation where the thinning is progressing, it is easily estimated that the occurrence of such an event becomes remarkable.

  Therefore, the present invention has been made in view of such circumstances, and it is possible to prevent the formation of a gap between the dielectric layer and the via electrode and to reliably connect the via electrode and the internal electrode. An object of the present invention is to provide a method for manufacturing a multilayer ceramic electronic component that can effectively prevent the occurrence of structural defects in a body layer and the like, and can manufacture products having excellent performance with high yield. .

  In order to solve the above problems, a method for manufacturing a multilayer ceramic electronic component according to the present invention includes at least one ceramic layer including a ceramic material for forming a dielectric layer and at least one conductor including a conductive material for forming an internal electrode. A step of forming a laminated body by laminating layers, a step of forming a via hole penetrating at least one of the ceramic layers and at least one of the conductor layers, and firing the laminated body in which the via holes are formed. Applying a conductive material for forming the via electrode in the via hole in the laminated body in which the dielectric layer and the internal electrode are formed, and the step of obtaining the laminated body in which the dielectric layer and the internal electrode are formed. A step of filling, and a step of forming a via electrode by subjecting the laminate in which the conductor material is filled in the via hole to a baking process.

  In the method of manufacturing a multilayer ceramic electronic component having such a structure, a laminate obtained by laminating a green sheet layer for forming a dielectric layer and an internal electrode green sheet layer containing a conductor material for forming an internal electrode is obtained. In the state where the via hole is formed, that is, before the via hole is filled with the conductive material for forming the via electrode, the baking treatment is once performed. For example, after the binder is removed from the ceramic layer as necessary, Ni or Ni alloy is used as the internal electrode to prevent oxidation of the internal electrode, so that the firing is necessary for sintering the ceramic layer in a reducing atmosphere. It is preferable to carry out a re-oxidation treatment for re-oxidizing the dielectric as necessary, for a predetermined time at temperature.

  Next, the conductive material for forming the via electrode is filled in the via hole of the sintered body thus obtained and baked (in other words, fired again), whereby the conductive material in the via hole is baked. To obtain a multilayer ceramic electronic component in which a via electrode is formed. At this time, since the ceramic layer has already been fired to become a dielectric layer which is a sintered body, the baking temperature can be made lower than the melting point of the conductor material which is sufficiently lower than the firing temperature of the ceramic layer. As a result, the degree of expansion and contraction of the dielectric layer is sufficiently suppressed. Therefore, even if the conductive material for forming the via electrode is baked in this state, the difference in relative expansion and contraction (stretching behavior) between the dielectric layer and the internal electrode and the via electrode is reduced. It is effectively prevented that the body layer, the internal electrode, and the via electrode are separated and a gap is generated between them.

  In addition, as described above, since the conductor material for forming the via electrode can be baked at a sufficiently low temperature as compared with the firing temperature of the ceramic layer, the internal electrode and the via electrode which are concerned in the conventional simultaneous firing process. The relative expansion and contraction behavior of the forming conductor material and the ceramic layer forming dielectric layer can be reduced. As a result, structural defects such as cracks and delamination in the dielectric layer are sufficient. To be suppressed.

  Specifically, as the conductive material for forming the internal electrode, a material containing the first metal particles having a melting point higher than the firing temperature of the ceramic material necessary for forming the dielectric layer is used. As a conductive material for forming, a second metal particle having a melting point lower than the firing temperature of the ceramic material necessary for forming the dielectric layer, and another third having a melting point higher than that of the second metal. The present invention is particularly useful when using those containing metal particles.

  As described above, in the conventional co-firing process of firing a laminate in which a via electrode forming conductor material is filled in a via hole, the via electrode forming conductor material is made of a metal having a melting point lower than the firing temperature of the ceramic layer. If it is included, it will melt during firing, and the desired via electrode cannot be formed. On the other hand, in the present invention, after firing the ceramic layer and the conductor layer containing the conductor material for forming the internal electrode, the conductor material for forming the via electrode is baked, so that the baking temperature of the ceramic layer is reduced. There is no need to raise the firing temperature, and the temperature can be lower than the melting point of the second metal mainly contained in the conductor material.

  In addition, when baking a conductor material for forming a via electrode, the reactivity between particles of the same metal contained in the conductor material for forming a via electrode is high. For example, the solid solution reaction between particles proceeds excessively and the particles are occupied. The volume may be reduced, and the space filling rate by the conductor particles in the via hole may be excessively reduced. In this case, filling of the via hole with the conductor becomes insufficient, and there is a possibility that sufficient electrical connection between the internal electrode and the via electrode in the via hole cannot be ensured. On the other hand, when a conductive material for forming a via electrode includes particles of another third metal having a melting point higher than that of the second metal in addition to the second metal, the melting point is relatively high. The third metal particles are bonded to the second metal in a state of being interposed between the second metal particles, and act as if the second metal particles are pinned (pinning action). The metal reaction between the two metal particles is moderately suppressed, and the space filling rate due to the metal conductor in the via hole due to the decrease in the occupied volume of the metal particles is suppressed. Therefore, the electrical connection between the internal electrode and the via electrode can be further ensured.

  From the viewpoint of a high melting point, it may be possible to use particles of a high melting point inorganic material such as ceramic instead of the third metal particles, but such an inorganic material has poor wettability with the reacting metal particles. Since it is sufficient, the metal reaction between the same kind of metal particles can be suppressed, but it is difficult to stay at the reaction site and it is discharged from the metal, so that it is difficult to effectively maintain the pinning action. Therefore, it is preferable to use high melting point metal particles in that the pinning action described above can be effectively maintained.

  Here, more specifically, the second metal mainly contained in the conductor material for forming the via electrode includes Cu (melting point: 1083 ° C.), Ag (melting point: 961 ° C.), and Au (melting point: 1063 ° C.). ), And the third metal is at least one metal of Ni (melting point: 1453 ° C.), Pt (melting point: 1769 ° C.), and Pd (melting point: 1552 ° C.). Is mentioned. Among these, the conductive material for forming the via electrode contains Cu as the second metal from the viewpoint of being particularly excellent in the above-described operational effects and excellent in both electrical characteristics and economic efficiency. A metal containing Ni is preferably used. Also, since the ESR can be reduced, it is advantageous that the via electrode mainly contains Cu.

  Moreover, the structure of the multilayer ceramic electronic component obtained by the manufacturing method of the multilayer ceramic electronic component of this invention can be expressed as follows.

  That is, the multilayer ceramic electronic component according to the present invention comprises a dielectric layer made of a fired ceramic material, a conductor material, and a plurality of internal electrodes spaced apart from each other inside the dielectric layer, and a conductor material. A via electrode penetrating the dielectric layer and connected to at least two of the plurality of internal electrodes, the internal electrode being a firing temperature of the ceramic material necessary for forming the dielectric layer A second metal having a melting point lower than the firing temperature of the ceramic material necessary for forming the dielectric layer, and the second metal The content ratio of the third metal to the second metal is greater than 0 and less than 40% by mass, preferably 2% by mass to 30% by mass. Is.

  Specifically, it is preferable that the second metal is at least one metal of Cu, Ag, and Au, and the third metal is at least one metal of Ni, Pt, and Pd. Among these, it is more preferable that the second metal is Cu and the third metal is Ni. In this case, the via electrode is more preferably formed from a conductor material in which the average particle diameter of the second metal particles is twice or more the average particle diameter of the third particles.

  In the present invention, “mainly” or “contained as a main component” means that the mass content of the component in the conductor material is larger than the total mass content of the other components. The phrase “mainly” or “as a main component” includes a plurality of components indicates that the total mass content of the plurality of components is larger than the total mass content of other components. Further, the “average particle size” of the particle is an arithmetic average of the parallel distance D1 of the minimum interval and the parallel distance D2 of the maximum interval that circumscribe the particle outer shape of the primary particle that can be observed with a scanning electron micrograph of the cross section of the structure. The average value is shown when the value is the particle size.

  According to the method for manufacturing a multilayer ceramic electronic component of the present invention, a firing treatment is performed in a state in which a via hole is formed in a laminate formed by laminating a ceramic layer and a conductor layer containing a conductor material for forming an internal electrode. After that, the via hole is filled with a conductive material for forming a via electrode, and then subjected to a baking process to obtain a multilayer ceramic electronic component. Therefore, the baking temperature of the conductive material for forming the via electrode is set to the firing of the ceramic layer. The temperature can be made lower than the melting point of the conductor material which is sufficiently lower than the temperature. As a result, the degree of expansion and contraction of the dielectric layer can be suppressed to a sufficiently small level, so that the degree of relative expansion and contraction (stretching behavior) of the dielectric layer, the internal electrode and the via electrode is reduced. Generation of gaps between the body and internal electrodes and via electrodes and generation of structural defects such as dielectric layers can be effectively prevented.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios in the drawings are not limited to the illustrated ratios. Further, the following embodiments are exemplifications for explaining the present invention, and are not intended to limit the present invention only to the embodiments. Furthermore, the present invention can be variously modified without departing from the gist thereof.

  FIG. 1 is a sectional view showing a schematic structure of an example of a multilayer ceramic electronic component obtained by using the method for manufacturing a multilayer ceramic electronic component according to the present invention. The multilayer ceramic capacitor 1 (multilayer ceramic electronic component) is a so-called surface-mount type multilayer ceramic capacitor, in which patterns of a plurality of dielectric layers 11 and a plurality of internal electrodes 12 are alternately stacked. Of these, every other layer that is spaced and opposed via each dielectric layer 11 is connected by a via electrode 14 provided so as to penetrate the dielectric layer 11 in the stacking direction. In addition, external connection pads 16 are connected to both ends of each via electrode 14. Bumps and the like may be formed on the external connection pads 16 as necessary.

  In the drawing, a plurality of dielectric layers 11 are described as separate layers. However, as will be described later, in the manufacturing process, the ceramic green sheets 2 that are precursor layers of the dielectric layers 11 are multi-staged. The layer laminated on is formed by firing treatment, and is integrally sintered by firing to constitute the dielectric layer 10 as a whole.

  Next, an example of a method for manufacturing the multilayer ceramic capacitor 1 according to the present embodiment will be described. 2 and 3 are process diagrams showing a part of an example of a procedure for manufacturing the multilayer ceramic capacitor 1.

First, to prepare a ceramic powder containing barium titanate (BaTiO ₃₎ -based ceramic for dielectric layer 11 is formed. The dielectric layer 11 contains barium titanate as a main component, and further contains a sintering aid component and other subcomponents. More specifically, for example, it contains barium titanate as a main component and at least one or more selected from magnesium oxide, yttrium oxide, dysprosium oxide, and holmium oxide as subcomponents. Further, as other subcomponents, at least one selected from barium oxide, strontium oxide, and calcium oxide, at least one selected from silicon oxide, manganese oxide, and chromium oxide, vanadium oxide, oxidation It may contain at least one selected from molybdenum and tungsten oxide.

As a method for preparing the ceramic powder for the dielectric layer 11 having such a composition, for example, Ba _1.005 TiO ₃ manufactured by a hydrothermal synthesis method is _added to (MgCO ₃ ) ₄ .Mg (OH) ₂ .5H ₂ O, MnCO. ₃ , BaCO ₃ , CaCO ₃ , SiO ₂ , Y ₂ O ₃ , V ₂ O ₅ are added and wet-mixed by a ball mill for about ten hours or more, and the final composition is Ba _1.005 TiO ₃ with MgO, MnO, Y _2. A method of obtaining a raw material powder containing O ₃ , (Ba _0.6 , Ca _0.4 ) SiO ₃ , and V ₂ O ₅ can be used. As an example of the composition, Ba _1.005 TiO ₃ , MgO: 0.5 mol%, MnO: 0.4 mol%, Y ₂ O ₃ : 1.0 mol%, (Ba _0.6 , Ca _0.4 ) SiO ₃ : 1.0 mol% V ₂ O ₅ : 0.05 mol%.

  Next, the obtained raw material powder is mixed with an organic solvent, an organic binder, and, if necessary, a plasticizer, an antistatic agent, a dispersant, an antifoaming agent, a surfactant, a wetting agent, and other additives. After forming a ceramic slurry, it is molded using a doctor blade method, a nozzle coater or the like, and a sheet-like ceramic green sheet 2 is formed on a substrate P such as a resin film such as polyethylene terephthalate (PET) as shown in FIG. Form.

  Here, the organic solvent is not particularly limited, and examples thereof include ethanol, butanol, propanol, acetone, diacetone, methyl ethyl ketone, methyl isobutyl ketone, benzene, bromochloromethane, toluene, and xylene. The type of the organic binder is not particularly limited, and examples thereof include polyvinyl butyral, polyvinyl alcohol, polyethylene, ethyl cellulose, acrylic, and acrylonitrile binders. Among these, polyvinyl butyral is used. More preferred. Examples of the plasticizer include phthalate and phthalate esters, derivatives thereof, and polyethylene glycol derivatives.

  Further, as shown in FIG. 3, a conductive material mainly containing a refractory metal (first metal) in each of the plurality of individual regions 3 for forming the multilayer ceramic capacitor 1 on the ceramic green sheet 2. A pattern for forming the internal electrode 12 shown in FIG. 1 is formed by screen printing the paste. The conductive paste is made of Ni, Pt, Pd, alloy powder or composite metal particles containing these metals as main components, and conductive powder containing metal particles having a melting point higher than the firing temperature of the ceramic green sheet 2 described later. It can be prepared by mixing with a co-material, an organic binder, an organic solvent, and, if necessary, a plasticizer, a dispersant, an antifoaming agent, an additive and the like. As the co-material, it is preferable to use the same type of ceramic as that contained in the ceramic green sheet 2 and may contain an appropriate additive. The type of the organic binder is not particularly limited, and examples thereof include ethyl cellulose, polyvinyl butyral, and acrylonitrile. Among these, ethyl cellulose is more preferable.

  Next, the ceramic green sheets 2 on which the patterns for forming the internal electrodes 12 for a plurality of pieces are formed and the ceramic green sheets 2 on which the patterns are not formed are alternately laminated by an appropriate method, and FIG. A multilayer structure in which a plurality of substrate structures of the multilayer ceramic capacitor 1 shown in FIG. 1 (a structure in which the via electrode 14 and the external connection pad 16 are not formed in FIG. 1) is formed is obtained. As a lamination method at this time, for example, the ceramic green sheet 2 shown in FIG. 2 is further formed on the ceramic green sheet 2 shown in FIG. 3 by using a doctor blade method, a nozzle coater or the like. The method of printing the pattern for forming the internal electrode 12 for a plurality of individual pieces shown, the substrate P such as a PET film was peeled from the ceramic green sheet 2 shown in FIG. 3 on the ceramic green sheet 2 shown in FIG. The method of laminating things sequentially is mentioned. At this time, it may laminate | stack before peeling the base material P, and may peel the one or both base materials P after that. Moreover, you may press-fit etc. by a heat | fever or pressurization etc. for every lamination | stacking.

  Next, using various press methods such as a die press, hydrostatic press (SIP), and heated isostatic press (WIP) alone or in combination, the laminated structure is further pressed (green press). . Then, a via hole (through hole) is formed at a position where the via electrode 14 is provided in the pressure-bonded laminated structure. Examples of the method for forming a via hole include a method using a micro drill, a method using a mechanical punch, a method using laser ablation, and the like. Among these, a method using a micro drill is preferable for the following reasons. In other words, depending on the thickness of the laminated structure, the mechanical punch may have insufficient punch strength, and the laminated structure or the punch itself may be bent.On the other hand, in the case of batch processing using a laser, May have a smaller diameter as it goes inside compared to the hole diameter (laser beam diameter) on the surface of the laminated structure, which increases the cost compared to the case of using a micro drill. Therefore, a method using a micro drill that hardly causes such inconvenience is preferable.

Next, the stacked structure in which the via hole is formed is cut and divided into chips. The cutting method is not particularly limited, and for example, dicing using a dicer can be used. Then, after the laminated structure divided into individual pieces is subjected to a binder removal treatment in a reducing atmosphere of H ₂ / N ₂ at about several hundred degrees C, an inert gas atmosphere, or the atmosphere, for example, 1100 ° C. to 1400 Firing is performed for a predetermined time in a reducing atmosphere of about 0 ° C. (for example, an atmosphere having an oxygen partial pressure of less than 1.0 × 10 ⁻² Pa, an H ₂ / N ₂ atmosphere). Furthermore, for example, at 900 to 1200 ° C., reoxidation treatment (annealing) for a predetermined time in an atmosphere (N ₂ atmosphere) having an oxygen partial pressure of 1.0 × 10 ⁻⁸ Pa or higher, for example, higher than the reducing atmosphere. To obtain a sintered structure in which the ceramic green sheet 2 is sintered with the via hole opened.

  Next, a conductive paste for forming the via electrode 14 is filled in the via hole of each sintered structure. The conductive paste includes, for example, particles of mainly at least one metal of Cu, Ag, and Au, or an alloy or a composite metal (second metal) containing each of these metals as a main component. , Pt, and Pd, or a conductive powder containing particles of an alloy or composite metal (third metal) containing each of these metals as a main component is mixed with an organic binder to prepare. The conductor powder mainly contains Cu powder (including alloy powder and composite metal powder containing Cu as a main component; the same shall apply hereinafter), and Ni powder (alloy powder and composite metal containing Ni as a main component). It is more preferable to add and mix powder. Moreover, it does not specifically limit as a kind of organic binder, For example, an ethylcellulose type | system | group, a polyvinyl butyral type | system | group, an acrylonitrile type | system | group etc. are mentioned, Among these, an ethylcellulose type | system | group is more preferable. Furthermore, from the viewpoint of improving the adhesion between the dielectric layer 11 and the via electrode 14, glass frit may be added as an auxiliary agent to the conductive paste.

  Here, the shape of the Cu particles and Ni particles contained in the conductor powder is not particularly limited, and examples thereof include a spherical shape, a square shape, and a flat shape. Among these, a spherical shape is preferable. Further, their particle size and particle size distribution are not particularly limited. For example, those having an average particle size of submicron order to several tens of microns order can be used.

  Here, the case of using a mixed conductor powder in which Ni powder is added to Cu powder will be described as an example. The content ratio of Ni to Cu in the mixed conductor powder is preferably greater than 0 and less than 40% by mass, It is more preferable that it is 2 to 30% by mass. If this content ratio is greater than 0, that is, if the Ni powder is contained in the Cu powder, the via hole is sufficiently filled with the via electrode 14 in the finally formed multilayer ceramic capacitor 1, and the internal electrode 12 and the via electrode 14 can be reliably connected to each other, the occurrence of structural defects can be easily suppressed, and the moisture resistance can be easily improved. On the other hand, if the content ratio is less than 40% by mass, the conduction performance between the internal electrode 12 and the via electrode 14 can be more reliably improved, and in addition, the occurrence of structural defects can be more reliably prevented. it can. Furthermore, when the content ratio is 2% by mass or more and 30% by mass or less, it is useful in that the moisture resistance of the multilayer ceramic capacitor 1 can be further reliably improved.

  Further, the case of using a conductor powder containing Cu powder and Ni powder will be described as an example. When the average particle size of Cu particles is twice or more than the average particle size of Ni particles, the multilayer ceramic capacitor 1 has a This is preferable because it is easy to prevent the occurrence of lamination. Further, the combination of using Ni as the main component of the conductor material of the internal electrode 12 and Cu as the main component of the conductor material of the via electrode 14 has a high activity of the alloy reaction between Ni and Cu (the reaction is dense). This is preferable because the coupling is strong and conduction is easily ensured. On the other hand, for example, when Ni is used as the main component of the conductive material of the internal electrode 12 and Ni is also used as the main component of the conductive material of the via electrode 14, the Ni of the internal electrode 12 subjected to the baking treatment and the via Since the reaction with Ni in the conductive material of the electrode 14 is relatively sparse, it tends to be difficult to ensure conduction between the two.

  Further, the method of filling the conductive paste into the via hole of the sintered structure is not particularly limited as long as the method can sufficiently perform the filling, and pressure printing, hand printing, vacuum suction, A technique such as pushing in with a squeegee can be exemplified.

Next, the binder structure in which the conductive paste is filled in the via hole is removed from the binder in, for example, an H ₂ / N ₂ reducing atmosphere, an inert gas atmosphere, or the atmosphere of about several hundred degrees Celsius. Then, for example, an H ₂ / N ₂ reducing atmosphere of about 700 ° C. to 900 ° C. or N ₂ gas as a main component, and oxygen is added by at least one kind of gas of H ₂ , H ₂ O, CO ₂ and CO. A baking process is performed for a predetermined time in an atmosphere in which the partial pressure is controlled to obtain a structure in which the via electrode 14 is formed (in the state where the external connection pad 16 is not formed in the multilayer ceramic capacitor 1 shown in FIG. 1). .

  Then, patterning is performed by a method such as applying a conductive paste containing an appropriate conductor on both end portions of the via electrode 14 on the upper wall surface and the bottom wall surface of the structure, and this is performed at a predetermined temperature in an appropriate atmosphere. The external connection pad 16 is formed by firing for a predetermined time to obtain the multilayer ceramic capacitor 1 shown in FIG.

  According to the multilayer ceramic capacitor 1 and the method of manufacturing the same according to the present invention described above, the firing process is performed on the multilayer structure of the ceramic green sheet 2 and the pattern of the conductive paste for forming the internal electrode 12 in which the via hole is formed. After the application, the via hole is filled with a conductive paste for forming the via electrode 14 and the baking process is performed. That is, when the conductive paste for forming the via electrode 14 is subjected to the baking process, the ceramic green sheet 2 is baked. Since the dielectric layer 11 (integrated dielectric layer 10) which is a bonded body has already been formed, the conductor material has a baking temperature sufficiently lower than the firing temperature of the ceramic green sheet 2 as described above. Therefore, the degree of expansion and contraction of the dielectric layer 11 can be suppressed sufficiently small.

  Therefore, even if the conductive paste for forming the via electrode 14 is baked in this state, the difference in the degree of relative expansion and contraction between the dielectric layer 11 and the internal electrode 12 and the via electrode 14 is reduced. As a result, it is possible to effectively prevent the dielectric layer 11 and the internal electrode 12 and the via electrode 14 from being separated to generate a gap therebetween. As a result, the via electrode 14 and the internal electrode 12 can be reliably conducted. In addition, generation of a gap in the via hole is prevented, and the via hole is sufficiently filled with the via electrode 14, so that a product with improved moisture resistance and less deterioration with time can be obtained.

  Furthermore, since the dielectric layer 11 and the internal electrode 12 are formed by baking before baking the conductive paste for forming the via electrode 14, the baking is performed at a temperature sufficiently lower than the baking temperature of the ceramic green sheet 2. It is possible to reduce the relative expansion and contraction behavior of the conductive paste for forming the internal electrode 12 and the via electrode 14 and the ceramic green sheet 2 that can occur in the conventional simultaneous firing process. Structural defects such as cracks in the body layer 11 and delamination can be sufficiently suppressed.

  Further, when a mixed conductor powder containing a metal powder such as Ni having a higher melting point is used in addition to a metal powder such as Cu as the conductive paste for forming the via electrode 14, particles such as Ni having a high melting point are formed. Bonding with them in the state of being interposed between particles of low melting point Cu, etc., and exerting a pinning action on the particles of Cu, etc., so that the progress of the metal reaction between the particles of Cu, etc. is moderately suppressed Can do. As a result, it is possible to effectively prevent the space filling rate due to Cu or the like in the via hole from being excessively decreased due to excessive reaction between metals such as Cu and a decrease in occupied volume. Therefore, the conduction between the internal electrode 12 and the via electrode 14 can be realized more reliably.

  As described above, since the multilayer ceramic capacitor 1 having excellent performance can be efficiently manufactured with high yield, productivity and economy can be improved.

  In addition, as above-mentioned, this invention is not limited to the said embodiment, In the range which does not deviate from the summary, it can add suitably. For example, in addition to the examples illustrated in the above embodiments, the method for manufacturing a multilayer ceramic electronic component in the present invention is not limited to the manufacture of a multilayer ceramic capacitor, but also for manufacturing other multilayer ceramic electronic components such as a multilayer ceramic inductor. Applicable.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Manufacture of multilayer ceramic capacitors)
First, a multilayer ceramic capacitor having the same structure as that shown in FIG. 1 was manufactured in the same manner as the manufacturing procedure described above. The specific main process conditions at this time were as follows. That is, first, the thickness of the dried ceramic green sheet was about 5 μm. Further, the thickness of the pattern of the conductive paste for forming the internal electrode formed on the ceramic green sheet was set to about 1.2 μm. Furthermore, the via hole formed in the laminated structure was drilled using a micro drill (drill diameter 150 μm, rotation speed 100,000 rpm). Furthermore, the division into pieces was performed using a dicer having a cutting blade having a thickness of 0.35 mm. Further, the binder removal of the laminated structure in which the via holes are formed is performed in a H ₂ / N ₂ reducing atmosphere at 400 ° C., and the subsequent firing is performed in a strong H ₂ / N ₂ reducing atmosphere at 1150 ° C. to 1300 ° C. Went for hours. Furthermore, filling the via hole with the conductive paste for forming the via electrode (via fill) was performed by repeating vacuum suction printing five times.

  For the formation of the internal electrode, a conductive paste containing Ni powder as a main component was used. On the other hand, for forming the via electrode, a conductive paste containing Cu powder as a main component and mixed conductor powder to which Ni powder was added was used. At this time, the average particle diameter of Cu particles, the average particle diameter of Ni particles, and the content ratio (% by mass) of Ni in the mixed conductor powder included in the conductive paste for forming the via electrode are variously changed, and a plurality of laminated layers A ceramic capacitor was manufactured.

(Evaluation 1)
The various multilayer ceramic capacitors thus obtained were evaluated for (1) conductivity, (2) crack generation rate, (3) delamination generation rate, and (4) moisture resistance load test failure rate.

  First, (1) the conductivity was evaluated by using, as an index, the ratio (percentage%) of the measured value of the capacitance to the expected capacitance (design specification value) of the multilayer ceramic capacitor. Although the presence or absence of continuity can be confirmed by current-resistance measurement, since the measurement of capacitance is higher in reading sensitivity than resistance measurement, more accurate evaluation can be performed. It was adopted.

  Also, (2) the crack generation rate was evaluated by observing the plane, side surface, and end surface of the obtained multilayer ceramic capacitor 10 times with a stereomicroscope and cracking the dielectric layer. The ratio of the number of individuals with cracks to the number of sample bases used for observation was calculated (percent%) and used as an index.

  Furthermore, (3) the delamination occurrence rate is evaluated by polishing the side surfaces of a plurality of multilayer ceramic capacitor samples manufactured under the same conditions so that the entire via cross section can be seen. The number of those with delamination) was counted, and the ratio (percentage%) of the number of individuals with delamination to the number of sample bases subjected to observation was calculated and used as an index.

  Furthermore, (4) the rate of occurrence of a moisture resistance load test failure is evaluated by measuring the leakage current after applying twice the rated voltage for 3 hours in a 121 ° C.-95% humidity environment to the obtained multilayer ceramic capacitor. When the value is one digit or more larger than the leakage current value at the start of the test, it is counted as a defect, and the ratio (percentage%) of the number of defects to the number of sample bases used for observation is calculated. Using.

  Various manufacturing conditions and various evaluation results are summarized in Table 1.

  From the results shown in Table 1, according to the method for manufacturing a multilayer ceramic electronic component according to the present invention, the conductivity is sufficiently high, the occurrence rate of structural defects such as cracks and delamination is small, and further, the defect in the moisture resistance load test It was confirmed that the incidence was also sufficiently low.

(Evaluation 2)
As a conductive paste for forming a via electrode, Cu particles having an average particle diameter of 20 μm, Ni particles having an average particle diameter of 1 μm, a Ni / Cu content ratio of 10% by mass, a side surface of a Cu multilayer ceramic capacitor sample, After polishing so that the entire cross section of the via can be seen, and further polishing with about 1000 sandpaper, the surface is mirror-finished using a 1 μm / 0.4 μm diamond paste (after rough finishing at 1 μm, Final finishing was performed at 0.4 μm. As a result of element mapping of the via cross section using EPMA (Electron-Probe Microanalyzer), it was confirmed that Ni particles were bonded to the Cu particles in a state of being interposed between the Cu particles.

  The present invention can prevent the formation of a gap between the dielectric layer and the via electrode to ensure conduction between the via electrode and the internal electrode, and effectively prevent the occurrence of structural defects in the dielectric layer and the like. Therefore, it is possible to manufacture a multilayer ceramic electronic component having excellent performance with a high yield. Therefore, a multilayer ceramic electronic component such as a multilayer ceramic capacitor or a multilayer ceramic inductor, and a device, apparatus, or system including the multilayer ceramic electronic component It can be used widely and effectively in facilities, etc. and their production.

It is sectional drawing which shows schematic structure of an example of the multilayer ceramic electronic component obtained using the manufacturing method of the multilayer ceramic electronic component by this invention. FIG. 3 is a process diagram showing a part of an example of a procedure for manufacturing the multilayer ceramic capacitor 1. FIG. 3 is a process diagram showing a part of an example of a procedure for manufacturing the multilayer ceramic capacitor 1.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Multilayer ceramic capacitor (multilayer ceramic electronic component), 2 ... Ceramic green sheet, 3 ... Piece area, 10, 11 ... Dielectric layer, 12 ... Internal electrode, 14 ... Via electrode, 16 ... Pad for external connection, P …Base material.

Claims (4)

Laminating at least one ceramic layer containing a ceramic material for forming a dielectric layer and at least one conductor layer containing a conductor material for forming an internal electrode;
Forming a via hole penetrating at least one of the ceramic layers and at least one of the conductor layers;
A step of obtaining a laminate in which a dielectric layer and an internal electrode are formed by performing a firing process on the laminate in which the via hole is formed;
Filling the via hole in the laminate in which the dielectric layer and the internal electrode are formed with a conductive material for forming a via electrode;
A step of forming a via electrode by subjecting the laminated body filled with the conductor material to the via hole to a baking treatment;
A method for manufacturing a multilayer ceramic electronic component comprising: As the conductor material for forming the internal electrode, a material containing a first metal particle having a melting point higher than the firing temperature of the ceramic material necessary for forming the dielectric layer,
As the conductor material for forming the via electrode, second metal particles having a melting point lower than the firing temperature of the ceramic material necessary for forming the dielectric layer, and a melting point lower than that of the second metal Using high third metal particles,
The method for producing a multilayer ceramic electronic component according to claim 1. The second metal is at least one of Cu, Ag, and Au;
The third metal is at least one metal of Ni, Pt, and Pd;
The manufacturing method of the multilayer ceramic electronic component of Claim 2. The second metal is Cu;
The third metal is Ni;
The manufacturing method of the multilayer ceramic electronic component of Claim 2.

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