JP6940371B2 - Chip electronic components and modules - Google Patents

Description

The present disclosure relates to chip-type electronic components and modules.

In recent years, chip-type electronic components represented by capacitors, piezoelectric elements, inductors, resistor components, and the like are increasingly required to be miniaturized due to the demand for mobile electronic devices (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2014-57019

The chip-type electronic component of the present disclosure has an insulating portion and a conductor portion provided inside the insulating portion, and is arranged so as to cover an effective portion that exhibits electrical characteristics and at least a part of the effective portion. It is provided with a component body having an insulating cover portion, and the cover portion has a plurality of particle group structures in which a plurality of ceramic particles are sintered, and the cover portion is located on the effective portion side. When the inner cover portion and the surface layer cover portion arranged on the inner cover portion so as to be located on the outermost surface are separated, the plurality of particle group structures formed on the surface layer cover portion partially pass through a space. Next to each other.

In the module of the present disclosure, the above-mentioned chip type electronic components are mounted on a substrate.

It is a perspective view which shows one Embodiment of a chip type electronic component. FIG. 5 is a cross-sectional view taken along the line ii-ii of FIG. It is an enlarged plan view of the part A of FIG. It is an enlarged plan view of the part B of FIG. It is an enlarged cross-sectional view of part C of FIG. It is a perspective view which shows the other aspect of a chip type electronic component. FIG. 7 is a cross-sectional view taken along the line viii-viii of FIG. It is an external perspective view which shows one Embodiment of a module.

FIG. 1 is a perspective perspective view showing an embodiment of a chip-type electronic component. FIG. 2 is a cross-sectional view taken along the line ii-ii of FIG. FIG. 3 is an enlarged plan view of part A in FIG. FIG. 4 is an enlarged plan view of a portion B of FIG. FIG. 5 is an enlarged cross-sectional view of portion C of FIG. FIG. 6 is an enlarged plan view of a portion D in FIG.

Here, a rough description of FIGS. 2 to 5 will be added. Reference numerals A and B shown in the C portion of FIG. 2 correspond to the A portion and the B portion in FIG. 1, respectively. FIG. 3 shows the arrangement of the particle swarm structure 13 in the surface layer cover portion 9A. FIG. 4 shows the structure of the inner cover portion 9B. FIG. 5 shows a state in which the particle swarm structure 13 constituting the surface layer cover portion 9A is arranged on the inner cover portion 9B.

The chip-type electronic component 1 shown in FIG. 1 has an external electrode 5 at opposite ends of the component body 3. The component main body 3 has an effective portion 7 and a cover portion 9 arranged so as to cover at least a part of the effective portion 7. The effective portion 7 is an insulating portion 7a and a conductor portion 7 provided inside the insulating portion 7a.
It has b. The effective part 7 exhibits electrical characteristics. The insulating portion 7a and the cover portion 9 are formed of an insulating ceramic material. The conductor portion 7b is made of metal. The conductor portion 7b may contain a metal oxide in addition to the metal as long as the desired conductivity is not impaired.

For example, a chip-type electronic component 1 such as a capacitor may be used in a state where a DC voltage is applied between the opposing external electrodes 5. As the size of the chip-type electronic component 1 becomes smaller, the distance between the two opposing external electrodes 5 becomes closer. As shown in FIG. 1, when the two external electrodes 5 indicated by reference numerals L are brought close to each other, the current flowing through the surface 3A of the component main body 3 becomes easy to pass between the external electrodes 5. The current flowing through the surface 3A of the component body 3 may reduce the insulating property of the chip-type electronic component 1. In other words, the chip-type electronic component 1 may have a reduced insulating property due to a current flowing through the surface 3A of the component body 3. The present disclosure addresses such a problem, and an object of the present disclosure is to provide a chip-type electronic component 1 having a small decrease in insulating property.

In the chip-type electronic component 1, the surface of the cover portion 9 is sparser than the inside. The cover portion 9 is formed of a sintered body obtained by sintering a plurality of ceramic particles 11. The cover portion 9 has a crystal structure having a particle group (secondary particles) formed by sintering a plurality of ceramic particles 11 as a unit. Hereinafter, the crystal structure in which the particle group is a unit is referred to as a particle group structure 13. The particle swarm structure 13 is mainly located on the surface layer portion of the cover portion 9. The particle swarm structure 13 has a flat shape. Here, the portion where the particle swarm structure 13 mainly exists is referred to as the surface layer cover portion 9A. On the other hand, the portion other than the surface layer cover portion 9A is the internal cover portion 9B. The inner cover portion 9B is located closer to the effective portion 7 than the surface layer cover portion 9A. The surface layer cover portion 9A and the inner cover portion 9B are integrally sintered.

As shown in FIG. 3, the particle swarm structure 13 is a crystal structure in which individual ceramic particles 11 (primary particles) are sintered via the grain boundary phase 12. The grain boundary phase 12 is mainly formed by the glass phase. The ceramic particles 11, which are primary particles, are formed only of a crystal phase without containing a glass phase or the like inside.

In the chip type electronic component 1, the surface layer cover portion 9A is in a sparser state than the inner cover portion 9B. In other words, the plurality of particle swarm structures 13 in the surface layer cover portion 9A exist on the inner cover portion 9B via the space 15 in the plane direction.

On the other hand, as shown in FIG. 4, the inner cover portion 9B has a structure in which the ceramic particles 11 are sintered by the grain boundary phase 14 such as the amorphous phase.

As described above, the chip-type electronic component 1 has a form in which a plurality of particle group structures 13 in the surface layer cover portion 9A exist on the inner cover portion 9B in the plane direction through the space 15. , The current that has passed through the cover portion 9 becomes difficult to pass between the particle group structures 13. As a result, the deterioration of the insulating property of the chip-type electronic component 1 is reduced, and the withstand voltage can be increased.

On the other hand, the inner cover portion 9B is denser than the surface layer cover portion 9A as described above. Since the inner cover portion 9B is dense, even if a wet component such as moisture adheres to the chip-type electronic component 1, the wet component is blocked by the surface 9Ba of the inner cover portion 9B, and it is difficult for the wet component to enter the inner cover portion 9B. .. Therefore, the chip-type electronic component 1 can maintain moisture resistance.

The particle swarm structure 13 has a contour for each unit. The contour is the surface of the individual ceramic particles 11 or the surface of the glass phase constituting the grain boundary phase 12. The average particle size of the ceramic particles 11 forming the particle group structure 13 is preferably 0.5 to 2 μm. The particle swarm structure 13 preferably has a minimum diameter of 30 μm or more and 300 μm or less when the surface layer cover portion 9A is viewed in a plan view. When the shortest diameter of the particle group structure 13 is 30 μm or more, the average spacing between the ceramic particles 11 may be wider than that of the crystal structures in which the ceramic particles 11 are adjacent to each other via the grain boundary phase 12. can. On the other hand, when the shortest diameter of the particle swarm structure 13 is 300 μm or less, many particle swarm structures 13 are formed on the surface 3A of the component body 3, so that there are many parts that act as current barriers on the surface 3A of the component body 3. Can be formed.

The average distance between adjacent particle swarm structures 13 is preferably 0.5 μm or more and 2.5 μm or less. When the average distance between the adjacent particle swarm structures 13 is 0.5 μm or more, a highly insulating current barrier can be formed between the adjacent particle swarm structures 13. On the other hand, when the average distance between the adjacent particle group structures 13 is 2.5 μm or less, many particle group structures 13 can be formed on the surface 3A of the component body 3. In addition, it becomes difficult for an electric current to flow along the space 15 between the particle swarm structures 13.

The range in the thickness direction of the particle swarm structure 13 is preferably one or more and three or less ceramic particles 11. When the range of the particle group structure 13 in the thickness direction is the range of one ceramic particle or more, a highly insulating current barrier can be formed between the particle group structures 13 adjacent to each other in the plane direction. On the other hand, if the number is 3 or less, a dense inner cover portion 7B can be formed thickly between the surface layer cover portion 9A and the effective portion 7, so that it becomes difficult for wet components such as moisture to penetrate deeply from the surface 3A, and the component body. Moisture resistance of 3 can be increased. In other words, the thickness of the particle swarm structure 13 corresponds to the depth of the space 15.

The average area of the particle swarm structure 13 is preferably 0.03 to 0.1 mm ² . When the average area of the particle swarm structure 13 is 0.03 mm ² or more, the effect of blocking the current flowing on the surface 3a of the component body 3 can be enhanced. Further, when the average area of the particle swarm structure 13 is 0.1 mm ² or less, the surface 3a of the component body 3 has many particle swarm structures 13, so that the current flowing through the surface 3a of the component body 3 is transferred. The blocking effect can be enhanced.

FIG. 6 is a perspective perspective view showing another aspect of the chip-type electronic component. FIG. 7 is a cross-sectional view taken along the line viii-viii of FIG. Each reference numeral attached to FIGS. 6 and 7 represents the chip-type electronic component 1 shown in FIG. 1 in the 20s. Each code is 21: chip type electronic component, 23: component body, 25: external electrode, 27: effective part, 27a: insulation part, 27b: conductor part, 29: cover part, 29A: surface layer cover part, 29B: inside. It is a cover part. In addition, 23a: the surface of the component body, 23b: the side surface of the component body, 27aa: the ceramic layer, 27bb: the internal electrode layer.

The effective portion 27 of the chip-type electronic component 21 has a plurality of conductor portions 27b inside the insulating portion 27a. In this case, the insulating portion 27a is composed of a plurality of ceramic layers 27aa. The conductor portion 27b is also composed of a plurality of internal electrode layers 27bb. In other words, the effective portion 27 has a structure in which a plurality of layers of the ceramic layer 27aa and the internal electrode layer 27bb are alternately laminated.

Although FIG. 6 shows only a laminated structure in which the number of layers of the internal electrode layer 27bb is three, the chip-type electronic component 21 described above is a multi-layer type having several hundred layers of the internal electrode layer 7bb. It can also be applied to a chip-type electronic component 21 provided with an effective portion 27. The effective portion 27 constituting the chip-type electronic component 21 has a structure having more internal electrode layers 27bb. Therefore, in the chip-type electronic component 21, when the size is fixed, the volume ratio of the cover portion 29 needs to be reduced when the volume ratio of the effective portion 27 in the component main body 23 becomes large.

Further, when the effective portion 27 is a laminated structure, the number of layers of the internal electrode layer 27bb increases in the component main body 23, and the thickness of the ceramic layer 27aa, which is the insulating portion 27a, becomes thin. .. As a result, there are many places in the effective portion 27 where an electric field is generated starting from the internal electrode layer 27bb. When the effective portion 27 is a laminated structure, the thickness of the cover portion 29A becomes thin, and the electric field tends to spread to a place closer to the surface layer cover portion 29A. When an electric field is applied to the chip-type electronic component 21 provided with the multi-layered laminated structure, the electric field easily spreads from the internal electrode layer 27bb to the cover layer 29, and the current easily flows through the surface layer cover portion 29A.

When the effective portion 27 is of such a laminated structure type and the structure of the chip type electronic component 1 shown in FIGS. 1 to 5 is applied as the surface layer cover portion 29A, a chip having high moisture resistance as well as withstand voltage is applied. The mold electronic component 21 can be obtained.

The cover portion 29 having the particle swarm structure 13 preferably covers at least two surfaces facing the internal electrode layer 27bb of the laminated structure. In this case, the two surfaces are the two outermost surfaces in the stacking direction of the internal electrode layer 27bb in the component body 23. When the particle swarm structure 13 is formed on the surface 23a of the component body 23, it is preferable that the particle swarm structure 13 is formed over the entire two surfaces facing the internal electrode layer 27bb of the surface 23a of the component body 23. The area ratio of the particle swarm structure 13 is preferably 90% or more of the area of the outermost surface of the component body 23. Further, the area ratio of the particle swarm structure 13 is preferably about the same on the two outermost surfaces in the stacking direction. In this case, the same degree means that the difference in the area ratio of the particle swarm structure 13 between the two outermost surfaces in the stacking direction is within 10%.

In the chip-type electronic component 21, the side surface 23b in the surface direction of the internal electrode layer 27bb, which is a surface perpendicular to the two surfaces 23a facing the internal electrode layer 27bb, is a stack of the internal electrode layers 27bb. The particle swarm structure 13 is formed at the outermost surface position in the direction. In FIG. 6, the location of the side surface 23b where the particle swarm structure 13 is present is indicated by reference numeral 23bb.

Examples of the chip-type electronic component 21 shown in FIGS. 6 and 7 include a laminated capacitor, a laminated piezoelectric element, a laminated inductor, and a laminated resistance element.

FIG. 8 is an external perspective view showing an embodiment of the module. In the module 31 shown in FIG. 8, when at least one of the chip-type electronic components 1 and 21 described above is represented by reference numeral 33, a plurality of chip-type electronic components 33 are mounted on the substrate 35. It will be the one that was done. In this case, if the chip-type electronic component 33 described above is used on the substrate 35 constituting the module 31, the module 31 having high withstand voltage and moisture resistance can be obtained. As a result, the chip-type electronic components 33 can be mounted closer to each other, and the module 31 having a high mounting density can be obtained. In this case, the chip-type electronic component 33 to be mounted may be a case where a plurality of chip-type electronic components 33 having the same electrical characteristics are mounted, or in addition, the chip-type electronic components 33 having different electrical characteristics may be mounted. May be implemented in a plurality of cases. Further, as shown in FIG. 8, the form may be mixed with an active element such as a semiconductor element 37.

Next, the method for manufacturing the chip-type electronic component 21 described above will be described using a capacitor as an example. It should be noted that such a form can be similarly applied not only to a capacitor but also to a chip type electronic component such as a piezoelectric element, an inductor and a resistance element.

In the method for manufacturing a capacitor described here, a conventional capacitor is used except that the ceramic green sheet used for the surface cover portion 9A and the ceramic green sheet used for the inner cover portion 9B are ceramic green sheets having different organic binder contents. It can be produced by a conventional manufacturing method.

For example, as the ceramic green sheet used for the surface layer cover portion 9A, it is preferable to use a ceramic green sheet having a smaller ratio of solid content (ceramic powder and organic binder) than the ceramic green sheet used for the inner cover portion 9B. According to such a method, a portion having less liquid phase components such as a glass phase can be formed on the extremely thin surface layer portion of the component body 3. In this case, the inside excluding the surface layer portion can be formed more densely than the surface layer portion.

According to such a manufacturing method, the portion having less liquid phase components such as the glass phase than the inside is made into ceramic powder from the surface of the ceramic green sheet instead of the thickness of the ceramic green sheet used for the surface layer cover portion 9A. It stays in the area of several thicknesses. It is considered that this is because when a plurality of ceramic green sheets are laminated to form a base laminate and fired, the portion having a low solid content ratio is biased toward the surface of the base laminate and the component body 3. As a result, it is possible to obtain chip-type electronic components 1 and 21 having a surface layer cover portion 9A in which a plurality of particle swarm structures 13 exist through the space 15.

Capacitors were manufactured and their characteristics were evaluated as follows. First, a dielectric powder prepared by adding an additive to barium titanate was prepared. Next, a ceramic green sheet was prepared by a doctor blade method using a slip prepared by mixing the above-mentioned dielectric powder and an organic vehicle (prepared by dissolving an organic binder in a solvent). A butyral resin was used as the organic binder to be contained in the organic vehicle when producing the ceramic green sheet.

Table 1 shows the composition of the slip for producing the ceramic green sheet for forming the ceramic layer of the effective portion, the ceramic green sheet for forming the inner cover portion, and the ceramic green sheet for forming the surface layer cover portion. rice field. The solvent in Table 1 is a 1: 1 mixture of ethyl alcohol and toluene. Here, the solid content is a combination of the dielectric powder and the organic binder. Each ceramic green sheet was blended so that the total of the solvent and the solid content was 100% by mass.

Next, a plurality of internal electrode patterns were formed as conductor patterns on the surface of the ceramic green sheet to prepare a pattern sheet. Nickel powder was used as the metal for the conductor paste for forming the internal electrode pattern. Ethyl cellulose was used as the resin for preparing the conductor paste. The amount of ethyl cellulose added was 5 parts by mass with respect to 100 parts by mass of nickel powder. As the solvent, a dihydroterpineol solvent and a butyl cellosolve were mixed and used.

Next, a plurality of the prepared pattern sheets were laminated to prepare a core laminate. Next, a ceramic green sheet for the inner cover layer was laminated on each of the upper surface side and the lower surface side of the core laminate, and further, a ceramic green sheet for the surface cover layer was laminated to prepare a base laminate. Table 1 shows the number of laminated ceramic green sheets used when producing the base laminate. After that, the base laminate was cut to prepare a main body molded body to be a component main body of the capacitor.

Next, the produced main body molded body was fired to produce a capacitor main body to be a component main body. This firing was carried out under the condition that the maximum temperature was set to 1080 ° C. in hydrogen-nitrogen. A roller kiln was used for this firing. The temperature rising rate was 5000 ° C./h.

Next, the produced capacitor body was subjected to a reoxidation treatment. The conditions for the reoxidation treatment were set to a maximum temperature of 1000 ° C. and a holding time of 5 hours in a nitrogen atmosphere.

The size of the obtained capacitor body was 1.5 mm × 1.5 mm × 0.7 mm, and the average thickness of the dielectric layer was 1.1 μm. The average thickness of the internal electrode layer was 0.8 μm. The design value of the capacitance was 10 μF.

Among the samples shown in Table 2, the sample No. No. 1 was produced by using the ceramic green sheets for the inner cover portion and the surface layer cover portion shown in Table 1 for the cover layer. Sample No. No. 2 was prepared by using a ceramic green sheet for the inner cover layer for all of the cover layers. In addition, sample No. For the effective parts 1 and 2, a ceramic green sheet for the ceramic layer of the effective part was used.

The manufactured capacitors were evaluated as follows.

The presence or absence of the particle group structure in the cover portion was determined by observing the surface of the capacitor body and the cross section of the capacitor body using a scanning electron microscope. Specifically, it was confirmed from a photograph taken by a scanning electron microscope. The shooting magnification was set to 10 times. The area of the area where the photograph was taken was 40 mm × 30 mm.

The area and diameter of the particle swarm structure were measured using photographs taken of the surface cover portion. In this case, the contour of the particle swarm structure was traced on the photograph, and the area of the traced contour was determined by image analysis. In addition, the diameter of a circle having the same area was obtained from the obtained area. Area and diameter are average values.

Further, for the surface layer cover portion, the state of the grain boundaries in which the particle group structures formed on the surface are adjacent to each other was determined, and the width and depth of the grain boundary phase (or space) were measured. The measurement was carried out by arbitrarily extracting 5 interfacial grain boundaries and 5 triple point grain boundaries from an area of 1 mm × 1.2 mm in the area of the photograph in which the surface layer cover was taken. The average value was calculated.

Sample No. In No. 1, a particle swarm structure in which a plurality of ceramic particles were sintered was observed on the surface of the capacitor body. On the other hand, no particle group structure was observed inside the capacitor body on which the particle group structure was formed, and the structure was such that the ceramic particles were sintered via the grain boundary phase such as the amorphous phase. In addition, sample No. In No. 1, the grain boundary between the particle group structures has a structure having a space in which a substance such as a grain boundary phase does not exist. The particle swarm structure was formed in a state where ceramic particles having an average particle size of 0.5 to 2 μm were sintered through the glass phase. The particle swarm structure had a thickness corresponding to the diameter of one ceramic particle as a whole. Table 2 shows the average area of the particle group structures, the spacing between adjacent particle group structures, and the depth of the space formed between the adjacent particle group structures.

Sample No. Regarding No. 2, no particle swarm structure formed through the space was observed, and the ceramic particles had a structure in which the ceramic particles were sintered via a grain boundary phase such as an amorphous phase.

The withstand voltage was measured with the boost speed set to 5 V / sec (boost 1). The number of samples was 30, and the average value was calculated.

The moisture resistance of the capacitor was evaluated by performing a wet load test. The wet load test was performed under the conditions of a temperature of 85 ° C., a humidity of 85% RH, and a DC voltage of 35 V.

From Table 1 and Table 2, the sample No. In No. 1, there was no sample that failed in the wet load test, and the withstand voltage was 150 V. On the other hand, sample No. No. 2 had a withstand voltage of 120 V, although there was no sample that failed in the wet load test.

1, 21, 33 ... Chip type electronic parts 3, 23 ... Parts body 5, 25 ... External electrodes 7, 27 ... Effective part 7a , 27a ・ ・ ・ ・ ・ Insulation part 7b, 27b ・ ・ ・ ・ ・ Conductor part 9, 29 ・ ・ ・ ・ ・ ・ ・ ・ Cover part 9A, 29A ・ ・ ・ ・ ・ Surface layer cover part 9B, 29B ・ ・ ・ ・ ・Inner cover 11 ・ ・ ・ ・ ・ ・ ・ ・ Ceramic particles 12, 14 ・ ・ ・ ・ ・ ・ Particle boundary phase 13 ・ ・ ・ ・ ・ ・ ・ ・ Particle group structure 15 ・ ・ ・ ・ ・ ・ ・ ・Space 27aa ・ ・ ・ ・ ・ ・ Ceramic layer 27bb ・ ・ ・ ・ ・ ・ ・ Internal electrode layer 31 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ Semiconductor element

Claims (8)

An effective portion having an insulating portion and a conductor portion provided inside the insulating portion and exhibiting electrical characteristics, an insulating cover portion arranged so as to cover at least a part of the effective portion, and an insulating cover portion.
Equipped with a component body that has
The cover portion has a plurality of particle swarm structures in which a plurality of ceramic particles are sintered.
When the cover portion is divided into an inner cover portion located on the effective portion side and a surface layer cover portion arranged on the inner cover portion so as to be located on the outermost surface,
The plurality of particle swarm structures formed on the surface layer cover portion are chip-type electronic components in which some of them are adjacent to each other with respect to space. The chip-type electronic component according to claim 1, wherein the range in the thickness direction of the surface layer cover portion is a range in which the ceramic particles are 1 or more and 3 or less. The chip-type electronic component according to claim 1 or 2, wherein the particle swarm structure is an individual ceramic particle sintered via an amorphous phase. The chip-type electronic component according to any one of claims 1 to 3, wherein the average distance between the particle swarm structures in the surface cover portion is 0.5 to 2.5 μm. The chip-type electronic component according to any one of claims 1 to 4, wherein the average area of the particle swarm structure in the surface cover portion is 0.03 to 0.1 mm ^2. In the effective portion, the insulating portion is composed of a plurality of ceramic layers, the conductor portion is composed of a plurality of internal electrode layers, and the ceramic layers and the internal electrode layers are alternately laminated in a plurality of layers. The chip-type electronic component according to any one of claims 1 to 5, which forms a structure. The chip-type electronic component according to claim 6, wherein the cover portion covers at least two surfaces of the laminated structure facing the internal electrode layer. A module in which the chip-type electronic component according to any one of claims 1 to 7 is mounted on a substrate.

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