JP2009049361A - Stacked electronic part and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stacked electronic part that can sufficiently suppress plating deposition on the surface of a porous green body when a terminal electrode is formed on an external electrode, thereby enabling a decrease in the reliability of products to be prevented, and a method of manufacturing the same. <P>SOLUTION: The laminated electronic part 1 is a PTC thermistor having a stacked body 4 containing a porous green body 2 made of ceramics and having a plurality of vacancies and a plurality of internal electrodes 3 formed within the porous green body 2, and is provided with at least one unit structure 10 in which the porous green body 2 and the internal electrodes 3 are stacked. External electrode 5, 5 are connected to the internal electrode 2, and terminal electrodes 7, 7 are formed on the external electrode 5, 5 by plating. Resin is filled in a plurality of vacancies of the porous green body 2 at a filling ratio of not less than 60%. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a laminated electronic component having a laminated structure of an element body made of ceramics and internal electrodes, and a method for manufacturing the same.

  Generally, thermistors, capacitors, inductors, LTCCs (Low Temperature Co-fired Ceramics), varistors and their composites, which have ceramic bodies, internal electrodes and external electrodes, are printed circuit boards such as printed circuit boards. The external electrode is soldered to a predetermined connection position. In that case, for example, if the external electrode (base electrode) made of Ag and the terminal electrode made of Ni layer and Sn layer are formed by plating, the bondability to the substrate by solder is improved and the productivity is improved. Can be.

  For example, Patent Document 1 discloses that in the plating process for forming such terminal electrodes, the electrical characteristics of the laminated electronic component are prevented from deteriorating due to the plating electrolyte entering the component element body. Therefore, an electronic component has been proposed in which all pores present on the surface portion of the ceramic body of the electronic component are impregnated with a silicone resin or a phenol resin.

Japanese Patent No. 270097

  By the way, the present inventor examined the physical properties and electrical characteristics of the above-mentioned various laminated electronic components in which terminal electrodes are plated on external electrodes. For example, a porous ceramic such as a PTC (Positive Temperature Coefficient) thermistor is used. In a multilayer electronic component having an element body, the terminal electrode metal may be plated up to the surface of the element body, the surface layer portion, and even the inside of the element body. It has been found that, sometimes, the plating reaches the internal electrodes, which can cause problems such as loss of product function.

  Specifically, external electrodes (underlying electrodes) were formed on both ends of the PTC thermistor, and Ni / Sn terminal electrodes were formed by electroplating with bereel plating. As a result, plating adhered to the entire surface of the ceramic body. As a result of inspecting the elemental distribution of Ni and Sn in the element cross section with EPMA (Electron-Probe Microanalyzer), it was found that a large amount of Ni adhered to the surface layer and Ni also adhered to a deeper part. did. From this, it is estimated that the plating solution infiltrates into the open holes that reach the internal electrodes and power is supplied from the internal electrodes, so that the plating adheres and grows from inside the element body. The Such plating adhesion phenomenon to the element body is similarly seen when electroless plating using a catalyst and when electroless plating is started by a contact method without using a catalyst. It is estimated that the plating adheres and grows from the inside of the opening (open pore) that reaches the internal electrode. On the other hand, when the entire surface of the ceramic body is impregnated with a silicone resin using the conventional method disclosed in Patent Document 1, depending on the resin impregnation conditions, the adhesion of the plating to the ceramic body is sufficiently performed. It was confirmed that it cannot be suppressed.

  Therefore, the present invention has been made in view of such circumstances, and even when a terminal electrode is formed by plating on an external electrode, plating adhesion to the surface of a porous body made of ceramics can be sufficiently suppressed. Accordingly, an object of the present invention is to provide a multilayer electronic component capable of preventing a decrease in product reliability and a method for manufacturing the same.

  In order to solve the above-mentioned problems, the present inventor has made physical properties of the element material that can cause plating adhesion on the surface of the porous ceramic element of the multilayer electronic component, conditions at that time, and resin in the pores of the element. Focusing on the relationship with the resin filling rate when impregnated, the present invention was completed as a result of diligent research. That is, the multilayer electronic component according to the present invention includes a porous element body (porous ceramic element body) mainly made of ceramics and including a plurality of pores, and at least one internal electrode provided in the porous element body. The porous body includes a plurality of pores filled with resin of 60% or more, and a laminated body having an external electrode connected to the internal electrode and a terminal electrode formed by plating on the external electrode. Filled at a rate.

The “pores” contained in the porous element body in the present invention are equivalent to “pores” defined in Japanese Industrial Standards JIS Z2500 and 2501. The “filling rate” of the resin in the porous element body is a value measured as follows. That is, first, the weight of the laminated electronic component in a state before the terminal electrode is formed by plating is dried at 150 ° C. for 1 hour under atmospheric pressure to evaporate the moisture (weight m1). Next, the weight of the impregnated water is measured by holding the laminated electronic component in a state of being immersed in water for 30 minutes in a vacuum (weight m2). Further, after drying the laminated electronic component at 200 ° C. for 1 hour under atmospheric pressure, the porous body is impregnated with an uncured resin (a monomer in the case of a polymerizable material) so that the resin does not adhere to the external electrode, The weight of the resin obtained by drying and curing (heat curing, polymerization) is measured (weight m3). And the following formula (1);
Filling rate (%) = 100 × (m3−m1) / {(m2−m1) × ρ} (1),
Substituting the weights m1, m2, and m3 and the density ρ of the resin in the dry and cured state into the relational expression represented by

  In the multilayer electronic component configured in this way, the pores of the porous body are filled with resin, and the pores (open pores) opened in the porous body are closed by the resin. When forming a terminal electrode on the electrode by plating, the plating solution enters the inside of the porous body through such openings, thereby preventing the plating solution from reaching the internal electrode and depositing / growing the plating. Is done. According to the knowledge of the present inventor, when the filling rate of the resin is 60% or more, the plating adhesion rate (ratio of the plating adhesion area to the exposed area) on the surface of the porous element body is approximately 5% or less. It was confirmed that it was kept low enough. In addition, it is preferable that the resin layer is formed on the exposed surface of the porous element body, preferably almost entirely, since the barrier effect is further enhanced.

  In addition, the PTC thermistor obtained by using the same method as that disclosed in the above-mentioned Patent Document 1 is subjected to a heat treatment such as reflow, or is heated to a high temperature environment by heating during mounting or heat up during operation. It has been confirmed that when exposed, the PTC characteristics may be deteriorated depending on the impregnation conditions of the resin, such that the resistance value at a high temperature is significantly reduced. This is probably because the flux used for soldering electronic components such as PTC thermistors flows into the pores of the porous body during heating, and the ceramic body is reduced by the residual flux. Presumed to be.

  On the other hand, in the multilayer electronic component according to the present invention, it has been confirmed that the occurrence of such a PTC characteristic defect can be significantly suppressed. In particular, when the filling rate of the resin in the porous body is 70% or more, the multilayer electronic component is wired. It has been found that the flux can be sufficiently prevented from flowing into the porous body during or after mounting on a substrate or the like, and the occurrence rate (frequency) of characteristic defects can be significantly reduced.

  Furthermore, when the temperature characteristics of the PTC thermistor obtained by using the above conventional method were evaluated, depending on the resin impregnation conditions, a significant amount of individuals that generate foam (so-called “explosion”) from the ceramic body was generated. Was also confirmed. In the conventional method, although the pores on the surface of the ceramic body are blocked, the air inside the pores expands when exposed to high temperatures due to the remaining pores inside the body. Presumed to be caused by rupture.

  On the other hand, in the multilayer electronic component according to the present invention, it has been confirmed that the occurrence of such “explosion” can be effectively suppressed, and in particular, when the filling rate of the resin in the porous body is 80% or more, “ It was also found that the occurrence rate (frequency) of “explosion” can be significantly reduced.

  Further, the present invention is further useful when the porous body is fired (sintered body) and the sintered density (measured density / theoretical density × 100%) is 90% or less. . That is, according to the research of the present inventors, when a porous element having a sintered density exceeding 90% is used, the adhesion of plating to the surface of the porous element is almost recognized at the time of forming the terminal electrode. In other words, it was confirmed that when the sintered density was 90% or less, the adhesion rate of plating to the surface of the porous element body rapidly increased as the sintered density decreased. This is because when the sintered density of the porous element body exceeds 90%, almost no open pores are generated, and even if voids are formed, many are closed pores and the plating solution is Although it does not penetrate, when the sintered density becomes 90% or less, it is presumed that the number of holes and the ratio to all the holes rapidly increase. Therefore, when applied to a laminated electronic component including a porous element body having a sintered density of 90% or less in which such a large amount of openings can be formed, the operational effects of the present invention are more suitably realized.

  In addition, it is preferable to further include an overcoat layer that covers the external electrode, because when the terminal electrode is plated on the surface of the external electrode, corrosion of the external electrode by the plating solution can be surely prevented.

  Furthermore, the method for manufacturing a multilayer electronic component according to the present invention is a method for effectively manufacturing the multilayer electronic component according to the present invention, which is mainly made of ceramics and includes at least a porous body including a plurality of pores. A step of forming a laminated structure by providing one internal electrode, a step of firing the laminated structure to form a laminated body (sintered body), and electrically connecting the conductive paste to the internal electrode of the laminated body A step of applying to the laminate so as to connect, a step of baking the conductive paste to form the external electrode, and impregnating the porous body with a resin, the resin in a plurality of pores, 60% or more, Preferably, the method includes a step of filling at a filling rate of 70% or more, more preferably 80% or more, and a step of forming a terminal electrode on the external electrode by plating.

  According to the multilayer electronic component and the method for manufacturing the same according to the present invention, since the plurality of pores included in the porous element body are filled with the resin at a filling rate of 60% or more, the terminal electrode can be formed by plating. , It is possible to prevent the plating solution from entering through the pores of the porous element body and flowing into the internal electrode, thereby sufficiently suppressing the adhesion of the plating to the porous element body, thereby reducing the reliability of the product. In addition, it is possible to eliminate inconveniences such as the occurrence of a characteristic failure when a high temperature is applied and the occurrence of “explosion” at a high temperature.

  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. Further, the present invention can be variously modified without departing from the gist thereof.

<First Embodiment>
FIG. 1 is a sectional view showing a schematic structure of a first embodiment of a multilayer electronic component according to the present invention. The multilayer electronic component 1 is a PTC thermistor having a multilayer body 4 including a porous element body 2 made of ceramics and having a plurality of pores, and a plurality of internal electrodes 3 formed in the porous element body 2. For example, at least one unit structure 10 in which the porous body 2 and the internal electrode 3 are laminated is provided. More specifically, the internal electrodes 3 having end portions exposed on one side surface of the multilayer body 4 and the internal electrodes 3 having end portions exposed on the other side surface of the multilayer body 4 are alternately stacked. .

  External electrodes 5 and 5 are provided on both side surfaces of the laminate 4 so as to cover the side surfaces, and each external electrode 5 is a group of internal electrodes 3 exposed from one side surface of the laminate 4 or It is electrically connected to the group of internal electrodes 3 exposed from the other surface of the laminate 4.

  Further, terminal electrodes 7 and 7 are formed on the outside of the external electrodes 5 and 5 by plating. These terminal electrodes 7 and 7 are joined to, for example, electrodes on a wiring board (not shown) by solder or the like. Each terminal electrode 7 has, for example, a two-layer structure including a Ni layer 7a and a Sn layer 7b that are stacked from the external electrode 5 side. The Ni layer 7a functions as a barrier metal which prevents the Sn layer 7b and the external electrode 5 from contacting each other and prevents corrosion of the external electrode 5 due to Sn, and has a thickness of about 2 μm, for example. Further, the Sn layer 7b has a function of improving the wettability of the solder, and the thickness thereof is, for example, about 4 μm.

When a PTC thermistor is manufactured as the multilayer electronic component 1 as in the present embodiment, the porous element body 2 needs to be made of ceramics, specifically, semiconductor ceramics as described above, and more specifically, For example, it is made of a barium titanate ceramic. In this barium titanate ceramic, part of Ba may be replaced with Ca, Sr, Pb, or the like, or part of Ti may be replaced with Sn, Zr, or the like as necessary. As donor elements to be added to obtain barium titanate semiconductor ceramics, rare earth elements such as La, Y, Sm, Ce, Dy, and Gd, and transition elements such as Nb, Ta, Bi, Sb, and W are used. Can be used. Further, if necessary, SiO ₂ , Mn or the like may be added to the barium titanate semiconductor ceramics.

  Thus, by forming the porous element body 2 of barium titanate semiconductor ceramics, the PTC thermistor characteristic (PTC characteristic) that the electric resistance rapidly increases at the Curie temperature can be obtained satisfactorily. Applications of such PTC thermistors include overcurrent protection, constant temperature heating elements, overheat detection and the like.

  The method for synthesizing the barium titanate-based ceramic powder used to form the porous element body 2 is not particularly limited. For example, a hydrothermal method, a hydrolysis method, a coprecipitation method, a solid phase method, A sol-gel method or the like can be used, and calcining may be performed as necessary.

  Further, the porous element body 2 is formed by filling a plurality of pores with a resin at a filling rate of 60% or more, preferably 70% or more, more preferably 80% or more. When the filling ratio of the resin is 60% or more, when the terminal electrode 7 is formed by plating, the plating solution enters the inside of the porous element body 2 from the openings (open pores) included in the porous element body 2. As a result, it is possible to sufficiently prevent the plating solution from reaching the internal electrode and causing the plating to adhere and grow. Further, when the filling rate of the resin in the porous element body 70 is 70% or more, the occurrence ratio of characteristic defects due to the inflow / residue of the flux into the porous element, which is a concern when mounting the laminated electronic component 1 or the like In particular, when the filling rate of the resin is 80% or more, when the laminated electronic component 1 is exposed to a high temperature, the air inside the pores may expand and burst. It is possible to keep the occurrence of “explosion” extremely low.

  In addition, it is preferable that the porous element body 2 has a resin layer formed on the exposed surface, preferably substantially the entire surface, because the barrier effect is further enhanced. In addition, the coverage with the resin layer on the surface of the porous element body 2 is preferably higher if the handling is not particularly inconvenient because the plating solution can be prevented from entering the opening (open pore).

  Here, FIG. 2 is an enlarged photograph showing a surface layer cross section of an example of a real porous element body 2 filled with a resin at a filling rate of 60% or more. A plurality of pores are formed inside the porous element body 2, and it is confirmed that many apertures communicate with the internal pores. It can be seen that a resin layer is formed on the surface of the element body 2.

  The type of the resin used for filling the pores of the porous element body 2 is not particularly limited, and can be a monomer, polymer, or the like as long as it can be impregnated into the porous element body 2 and then cured. In the case of a resin that is cured by a polymerization reaction after impregnation, for example, an epoxy resin, a phenol resin, or an addition polymerization type (addition polymerization reactivity) silicone resin is preferably used. Among these, it is more preferable to use an addition polymerization type. Monomers for obtaining addition polymerization type resins include those having an unsaturated reactive group, particularly preferably those having a (meth) acryloyl group, a vinyl group, or a derivative group thereof.

  When a dehydration-condensation type resin is used, water is generated as a reaction product during the polymerization, and voids can be generated by releasing the water from the pores of the porous element body 2 whereas addition polymerization is performed. When the type resin is used, water is not generated at the time of polymerization and curing, so that generation of voids can be suppressed and the filling rate of the pores of the porous element body 2 can be further increased as compared with the case of using a dehydration condensation type resin. .

  The porous body 2 is a sintered body, and the sintered density is not particularly limited. However, when the sintered density is 90% or less, the above-described effects due to the resin filling are remarkably exhibited. That is, when the sintered density of the porous element body 2 exceeds 90%, the amount of plating attached to the surface of the porous element body 2 when the terminal electrode 7 is plated is not significant, whereas the sintered density is 90%. When the ratio is less than or equal to%, the amount and ratio of the pores of the porous element body 2 increase as the sintered density decreases, and the adhesion rate of plating to the surface of the porous element body 2 tends to increase rapidly. . Therefore, when the porous element body 2 has a sintered density of 90% or less at which such a large amount of openings can be formed, the openings are filled with resin, so that the plating adheres to the surface of the porous element body 2. Can be effectively deterred.

  On the other hand, for the internal electrode 3, for example, a material mainly composed of Ni, Cu, or Al is used from the viewpoint of enabling reliable ohmic contact with the porous body 2. It may be a composite material, and by using a porous body 2 that can be fired at a low temperature, Cu (melting point 1083 ° C.) and Al (melting point 660 ° C.) having a melting point lower than Ni (melting point: 1450 ° C.) should be used. Can do.

  On the other hand, the external electrode 5 is obtained, for example, by applying and baking a conductive paste on the side surface of the laminate 4. Examples of the conductive paste for forming the external electrode 5 mainly include glass powder, an organic vehicle (binder), and a metal powder. By firing the conductive paste, the organic vehicle is volatilized, Finally, the external electrode 5 containing a glass component and a metal component is formed. In addition, you may add various additives, such as a viscosity modifier, an inorganic binder, and an oxidizing agent, to an electrically conductive paste as needed.

  In the present embodiment, the external electrode 5 includes, for example, Ag and Al as metal components, and Al or the like is a constituent component of the internal electrode 3, such as Ni, Cu, or Al, and the external electrode 5. By interposing in the junction part with Ag contained in the electrode, the junction area between the internal electrode 3 and the external electrode 5 is increased, whereby the connection resistance can be sufficiently lowered, and the internal electrode 3 It is also possible to increase the mechanical bonding strength with the external electrode 5.

  Next, a method for manufacturing the multilayer electronic component 1 according to the present embodiment will be described with reference to FIGS. 3-7 is process drawing which shows an example of the procedure which manufactures the multilayer electronic component 1. FIG.

First, as a starting material, a predetermined amount of BaCO ₃ , TiO ₂ and Sm nitrate solution are mixed, put into a polyethylene pot together with pure water and zirconia balls, pulverized and mixed for 5 hours, and then the mixture is evaporated and dried. The mixed powder was calcined at 1100 degrees.

Next, the calcined powder is again pulverized with a ball mill for 5 to 30 hours using pure water and zirconia balls, and then evaporated and dried to obtain a barium titanate semiconductor ceramic powder. For example, a barium titanate semiconductor ceramic powder having a composition of (Ba _0.9985 Gd _0.0015 ) _0.995 (Ti _0.9985 Nb _0.0015 ) O ₃ is obtained.

  Next, an organic solvent, an organic binder, a plasticizer, and the like are added to the obtained powder to form a ceramic slurry, which is then molded by a doctor blade method to form a sheet-like porous body 2 shown in FIG. Get a green sheet.

  Furthermore, as shown in FIG. 4, the pattern of the internal electrode 3 is formed on the sheet-like porous body 2 by screen printing a conductive paste containing Ni, Cu, or Al as a metal component.

  Next, as shown in FIG. 5, a plurality of porous element bodies 2 on which internal electrodes 3 are formed and a plurality of porous element bodies 2 on which no internal electrodes 3 are formed are alternately laminated, and further pressurized. Thus, the laminated structure 40 is obtained.

  Then, as shown in FIG. 6, the laminated structure 40 is cut to be divided into individual laminated structures 41. The end of the internal electrode 3 is exposed from the side surface of the laminated structure 41 after cutting.

Next, the laminated structure 41 is subjected to a binder removal treatment in the air, and then fired at 1300 ° C. for 2 hours in a strong reducing atmosphere of H ₂ / N ₂ = 3/100, whereby the laminated body 4 is sintered. obtain. Thereafter, reoxidation treatment is performed in the air at a temperature of 600 ° C. to 1000 ° C. for 1 hour.

  Next, as shown in FIG. 7, a conductive paste containing Ag, Al, and the like is applied to the side surface of the laminate 4 and fired in the air at a temperature of 600 ° C. to 1000 ° C. for 1 hour to several hours. The external electrode 5 is formed.

  Next, the porous element body 2 is filled with resin. The filling method is not particularly limited. (1) The entire porous body 2 is covered with an appropriate member in a state where the external electrodes 5 and 5 are covered with an appropriate member (a monomer that is polymerizable if it is polymerizable). , Prepolymer: the same applies to the following) and retaining for a predetermined time to impregnate the resin in the pores of the porous body 2, and then heating to cure the resin, (2) external electrodes 5, 5 After immersing the entire porous element body 2 in an uncured resin without covering the part, impregnating the resin in the pores of the porous element body 2, and removing the resin adhering to the external electrodes 5 and 5 with a solvent or the like And a method of curing the resin by heating, and (3) a method of press-fitting uncured resin from the exposed surface of the porous element body 2.

  The filling rate of the resin into the porous body 2 can be adjusted by repeating the resin impregnation once or a plurality of times and adjusting the number of times as appropriate. It is possible to increase the rate. Alternatively, the filling rate of the resin into the porous body 2 can also be adjusted by adjusting the viscosity of the resin. Further, although depending on the type of resin, for example, in the case of a silicone-based resin, as a heat curing condition, a method of heating at 70 ° C. for 30 minutes and further heating at 180 ° C. for 1 hour can be exemplified. Furthermore, when the monomer or prepolymer is polymerized and cured by heating, if the resin also serves as an ultraviolet curable resin so as to promote cross-linking of the resin layer on the surface of the porous body 2, ultraviolet irradiation and heating can be performed simultaneously. Good.

  Further, as shown in FIG. 2, in order to form a resin layer on the surface of the porous element body 2, the porous element body 2 is impregnated with resin, and then the porous element body 2 is not washed or sufficiently washed. What is necessary is just to heat-cure in the state which does not carry out.

  Further, as shown in FIG. 1, a terminal electrode 7 is formed by sequentially depositing a Ni layer 7a and a Sn layer 7b on the surface of the external electrode 5 by electroplating. For example, in the formation of the Ni layer 7a, a barrel plating method is adopted, and Ni of 2 μm is deposited using a watt bath. Further, in forming the Sn layer 7b, a barrel plating method is adopted, and Sn is deposited by 4 μm using a neutral tin plating bath. Then, solder is formed on the terminal electrode 7 or an electrode of a wiring board (not shown), and the solder is melted to electrically connect the terminal electrode 7 and the electrode of the board.

  According to the method for manufacturing the multilayer electronic component 1, the conductive paste for the external electrode 5 can be fired in the air atmosphere. Thereby, compared with the case where it bakes in a reducing atmosphere, atmosphere control becomes simple and can reduce manufacturing cost. In addition, as described above, in particular, when a PTC thermistor is manufactured, if the conductive paste for forming the external electrode is baked in a reducing atmosphere, the laminate does not exhibit the PTC characteristics. The external electrode 5 can be formed while maintaining the PTC characteristics of the body 4.

Second Embodiment
FIG. 8 is a sectional view showing a schematic structure of a second embodiment of the multilayer electronic component according to the present invention. The multilayer electronic component 9 is the same as the multilayer electronic component 1 shown in FIG. 1 except that an overcoat layer 8 containing Ag as a metal component is formed on the surface of the external electrode 5 so as to cover the external electrode 5. It is configured. The overcoat layer 8 can be formed, for example, by printing and baking a conductive paste containing Ag. Although illustration is omitted, in FIG. 8, terminal electrodes 7 and 7 are laminated on the outside of the overcoat layers 8 and 8.

  According to the multilayer electronic component 9 having such a structure, since the overcoat layer 8 is formed on the surface of the external electrode 5, Al or the like contained in the external electrode 5 forms the terminal electrode 7 as shown in FIG. It can prevent more reliably that it is corroded by the plating solution for doing.

  In addition, as above-mentioned, this invention is not limited to said each embodiment, In the range which does not deviate from the summary, it can add suitably. For example, in the multilayer electronic component 1, the porous element body 2 may be impregnated with the resin before forming the external electrode 5. In the multilayer electronic component 9, before or after the formation of the external electrode 5 or overcoat layer After the formation of 8, the porous element body 2 may be impregnated with resin. Furthermore, the porous element body 2 may be a ceramic, and need not be a semiconductor ceramic. For example, when a multilayer ceramic capacitor is manufactured as the multilayer electronic component 1, 9, the porous element body 2 can be made of an insulating ceramic. Furthermore, at least one internal electrode 3 may be formed.

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

<Manufacture of PTC thermistors>
In the same manner as the manufacturing procedure described above, the composition has a porous element body 2 made of (Ba _0.9985 Gd _0.0015 ) _0.995 (Ti _0.9985 Nb _0.0015 ) O ₃ and a plurality of internal electrodes 3 made of Ni of 3.2 mm × 1. A laminated body 4 having a size of 6 mm × 0.5 mm was prepared, and conductive pastes having different contents of Al and Ag were applied to the side surfaces of the laminated body 4 and fired at 600 ° C. in an air atmosphere to external electrodes. 5 was formed. After impregnating this porous element body 2 with an addition polymerization type silicone monomer, the resin was polymerized and cured under heating conditions of heating at 70 ° C. for 30 minutes and further heating at 180 ° C. for 1 hour. Further, the terminal electrodes 7 and 7 are formed on the external electrodes 5 and 5 by using a watt bath by barrel plating with a Ni thickness of 2 μm and a neutral tin plating bath with a thickness of 4 μm. A PTC thermistor as a laminated electronic component was obtained.

(Examples 1-5)
By changing the filling rate of the resin into the porous body 2 having a sintered density of 80%, and according to the PTC thermistor manufacturing procedure, five types of PTC thermistors having a filling rate of 60% or more of the resin according to the present invention are used. Manufactured. The filling rate of the resin was adjusted as appropriate by the number of impregnations by repeating the impregnation once or plural times.

(Comparative Example 1)
A plurality of PTC thermistors having a resin filling rate of 0% were manufactured by the above-described PTC thermistor manufacturing procedure except that the porous element body having a sintered density of 80% was not impregnated and filled with the resin.

(Comparative Examples 2 to 4)
A plurality of PTC thermistors each having a resin filling rate of less than 60% were manufactured by changing the filling rate of the resin into the porous body having a sintered density of 80% and manufacturing the PTC thermistor.

(Test evaluation 1)
For the PTC thermistors obtained in each of the examples and comparative examples, the plating adhesion rate (%) on the surface of the porous element body, the occurrence rate of characteristic defects after mounting the PTC thermistor on the wiring board (%), the failure in the explosion test The incidence (%) was measured and evaluated. The plating adhesion rate (%) on the surface was calculated from the area of the plated region with respect to the exposed area of the porous body of the PTC thermistor. Also, the characteristic failure rate (%) after mounting is 10% higher than the resistance value before reflow after mounting 100 samples for each PTC thermistor on the wiring board by reflow processing. It was calculated from the ratio of the number of individuals that decreased. Furthermore, the defect occurrence rate (%) in the explosion test was calculated from the ratio of the number of individuals in which 100 samples for each PTC thermistor were immersed in silicon oil at 260 ° C. and foamed from the porous body. The results are summarized in Table 1. FIG. 9 is a graph of the data in Table 1.

  From Table 1 and FIG. 9, when the filling rate of the resin to the porous body 2 is 60% or more, the plating adhesion rate on the surface of the porous body can be sufficiently suppressed, and the filling rate is 70% or more. It is confirmed that the failure rate of characteristics after mounting the PTC thermistor on the wiring board can be sufficiently improved, and that the failure rate in the explosion test can be sufficiently reduced when the filling rate is 80% or more. It was.

  FIG. 10 and FIG. 11 are a plane external view photograph of a porous body of a PTC thermistor of a comparative example having a resin filling rate of 0% (plating adhesion rate of 100%), and a cross-sectional enlarged photograph of the surface layer portion, respectively. 12 and 13 are diagrams showing element distributions of Ni and Sn, respectively, when the cross section is observed with EPMA. From these results, in the PTC thermistor in which the porous element body is not impregnated / filled with resin, the surface of the porous element body has a metallic luster, and Ni penetrates to a deep region inside the porous element body. Turned out to be.

  14 and 15, FIG. 16 and FIG. 17, FIG. 18 and FIG. 19, FIG. 20 and FIG. 21 respectively show a resin filling rate of 42% (plating adhesion rate of 31%) and a resin filling rate of 56% (plating adhesion). Each of the PTC thermistors of the comparative example with a rate of 9.1%), the resin filling rate of 82% (plating adhesion rate of 3.2%), and the resin filling rate of 98% (plating adhesion rate of 0.5%). It is the plane external appearance photograph of a porous element | base_body, and the cross-sectional enlarged photograph of those surface layer parts.

(Reference Examples 1-6)
The PTC thermistor was manufactured in the same procedure as in Comparative Example 1 by changing the sintered density of the porous element body 2, and the relationship between the sintered density and the plating adhesion rate to the surface of the porous element body was evaluated. The results are summarized in Table 2. FIG. 22 is a graph of the data in Table 1.

  From Table 2 and FIG. 22, when the sintered density of the porous element body is 90% or less, the adhesion of the plating is remarkable to the extent that the plating adhesion rate exceeds 80%, whereas the sintering density is 90%. When the percentage exceeds 50%, the plating adhesion rate decreases rapidly, and it has been found that the adhesion of the plating is almost inconvenient.

  The present invention relates to a thermistor, a capacitor, an inductor, a LTCC (Low Temperature Co-fired Ceramics), a varistor, a laminated electronic component composed of a composite part thereof, and a device, an apparatus, a system, a facility, and the like including them, and Can be widely used in the manufacture of

It is sectional drawing which shows schematic structure of 1st Embodiment of the multilayer electronic component by this invention. It is an enlarged photograph which shows the surface layer cross section of an example of the real thing of the porous element | base_body 2 with which the resin was filled with the filling rate of 60% or more. It is process drawing which shows an example of the procedure which manufactures a laminated electronic component. It is process drawing which shows an example of the procedure which manufactures a laminated electronic component. It is process drawing which shows an example of the procedure which manufactures a laminated electronic component. It is process drawing which shows an example of the procedure which manufactures a laminated electronic component. It is process drawing which shows an example of the procedure which manufactures a laminated electronic component. It is sectional drawing which shows schematic structure of 2nd Embodiment of the multilayer electronic component by this invention. It is a graph which shows the plating adhesion rate of the surface with respect to the filling rate of the resin to a porous element body, the characteristic defect occurrence rate after mounting, and the defect occurrence rate in the explosion test. It is a plane external appearance photograph of the porous element body of the PTC thermistor of the comparative example with a resin filling rate of 0% (plating adhesion rate of 100%). It is a cross-sectional enlarged photograph of the surface layer part of the porous element body of the PTC thermistor of the comparative example of 0% of resin filling rate (plating adhesion rate 100%). It is a figure which shows element distribution of Ni when the cross section of the surface layer part of the porous body of the PTC thermistor of the comparative example of 0% of resin filling rate (plating adhesion rate 100%) is observed by EPMA. It is a figure which shows element distribution of Sn when the cross section of the surface layer part of the porous element body of the PTC thermistor of the comparative example of 0% of resin filling rate (plating adhesion rate 100%) is observed by EPMA. It is a plane external appearance photograph of the porous element body of the PTC thermistor of the comparative example of resin filling rate 42% (plating adhesion rate 31%). It is a cross-sectional enlarged photograph of the surface layer part of the porous element body of the PTC thermistor of the comparative example with a resin filling rate of 42% (plating adhesion rate of 31%). It is a plane external appearance photograph of the porous element body of the PTC thermistor of the comparative example of 56% of resin filling rate (plating adhesion rate 9.1%). It is a cross-sectional enlarged photograph of the surface layer part of the porous element body of the PTC thermistor of the comparative example of 56% of resin filling rate (plating adhesion rate 9.1%). It is a plane external appearance photograph of the porous element body of the PTC thermistor of the comparative example of resin filling rate 82% (plating adhesion rate 3.2%). It is a cross-sectional enlarged photograph of the surface layer part of the porous element body of the PTC thermistor of the comparative example of resin filling rate 82% (plating adhesion rate 3.2%). It is a plane external appearance photograph of the porous element body of the PTC thermistor of the comparative example of resin filling rate 98% (plating adhesion rate 0.5%). It is a cross-sectional enlarged photograph of the surface layer part of the porous body of the PTC thermistor of the comparative example with a resin filling rate of 98% (plating adhesion rate of 0.5%). It is a graph which shows the plating adhesion rate to the surface of a porous element with respect to the sintered density of a porous element.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,9 ... Laminated electronic component, 2 ... Porous element body, 3 ... Internal electrode, 4 ... Laminated body (sintered body), 5 ... External electrode, 7 ... Terminal electrode, 7a ... Ni layer, 7b ... Sn layer, 8 ... overcoat layer, 10 ... unit structure, 40, 41 ... laminated structure.

Claims (3)

A laminate comprising a porous body mainly made of ceramics and including a plurality of pores, and at least one internal electrode provided in the porous body;
An external electrode connected to the internal electrode;
A terminal electrode formed by plating on the external electrode;
With
The porous element body is formed by filling the plurality of pores with a resin at a filling rate of 60% or more.
Laminated electronic components. The porous body is fired and has a sintered density of 90% or less.
The multilayer electronic component according to claim 1. A step of forming a laminated structure by providing at least one internal electrode in a porous body mainly made of ceramics and including a plurality of pores;
Firing the laminated structure to form a laminated body;
Applying a conductive paste to the laminate so as to be electrically connected to an internal electrode of the laminate;
Firing the conductive paste to form external electrodes;
Impregnating the porous body with resin, and filling the plurality of pores with resin at a filling rate of 60% or more;
Forming a terminal electrode on the external electrode by plating;
A method of manufacturing a laminated electronic component having