Coil component and method of manufacturing the coil component

Abstract

A coil component that can be miniaturized while ensuring insulation reliability between internal conductors, and a method for manufacturing such a coil component are provided. [Solution] The coil component includes a base including metal magnetic particles 31 having a first average particle size and ceramic particles 32 having a second average particle size smaller than the first average particle size, and a coil conductor provided within the base, the coil conductor including a first conductor portion and a second conductor portion provided within the base so as to face the first conductor portion. In one embodiment, in an inter-conductor region of the base between the first conductor portion and the second conductor portion, the volume ratio of the ceramic particles to the total volume of the metal magnetic particles and the ceramic particles is 3 vol% or more. In one embodiment, the content of the metal magnetic particles in regions of the base other than the inter-conductor region is greater than the content of the metal magnetic particles in the inter-conductor region.

Description

[Technical Field]

[0001] The present invention relates primarily to coil components and methods for manufacturing coil components. [Background technology]

[0002] Various magnetic materials have been used as the magnetic substrate of electronic components. For example, ferrite is often used as the magnetic material for coil components such as inductors. Ferrite has high magnetic permeability, making it suitable as a magnetic material for the substrate of coil components.

[0003] Metallic magnetic materials containing metallic magnetic particles are known as magnetic materials for electronic components other than ferrite. Because metallic magnetic materials have a higher saturation magnetic flux density than ferrite, they are suitable as materials for the magnetic substrate of coil components through which large currents flow.

[0004] An insulating film is provided on the surface of each metal magnetic particle contained in a magnetic substrate to prevent short circuits between adjacent metal magnetic particles. However, magnetic substrates made from metal magnetic materials have a lower volume resistivity than magnetic substrates made from ferrite, making them more susceptible to dielectric breakdown. Japanese Patent Application Laid-Open No. 2017-092431 discloses a coil component in which three or more metal magnetic particles are arranged between internal conductors to improve insulation in the region between the internal conductors of the magnetic substrate. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2017-092431 Summary of the Invention [Problem to be solved by the invention]

[0006] Coil components are required to be compact as well as have high insulation reliability. Increasing the gap between opposing internal conductors improves insulation reliability, but this increases the dimensions in the thickness direction.

[0007] An object of the present invention is to provide a coil component that can be miniaturized while ensuring insulation reliability between internal conductors, and a method for manufacturing such a coil component. Other objects of the present invention will become apparent throughout the description of the entire specification. [Means for solving the problem]

[0008] A coil component according to one embodiment of the present invention includes a base including metal magnetic particles having a first average particle size and ceramic particles having a second average particle size smaller than the first average particle size, and a coil conductor provided within the base, the coil conductor including a first conductor portion and a second conductor portion provided within the base so as to face the first conductor portion. In one embodiment, in an inter-conductor region of the base between the first conductor portion and the second conductor portion, the volume ratio of the ceramic particles to the total volume of the metal magnetic particles and the ceramic particles is 3 vol% or more.

[0009] In one embodiment of the present invention, the content ratio of the ceramic particles to the metal magnetic particles in the inter-conductor region is 15 vol % or less.

[0010] In one embodiment of the present invention, the first conductor portion and the second conductor portion are made of a conductive material containing a metal, and the substrate does not substantially contain atoms of the metal in the inter-conductor region.

[0011] In one embodiment of the present invention, the ceramic particles are selected from the group consisting of silica, alumina, zirconia, and the like. It consists of titanium or titania.

[0012] In one embodiment of the present invention, the second average particle size is 1 / 50 or less of the first average particle size. In one embodiment of the invention, the second average particle size is 1 / 200 or more of the first average particle size.

[0013] One embodiment of the present invention relates to a circuit board including the above-described coil component. One embodiment of the present invention relates to an electronic component including the circuit board described above.

[0014] A method for manufacturing a coil component according to an embodiment of the present invention includes: and ceramic particles having a second average particle size smaller than the first average particle size, preparing a compact having a coil conductor disposed therein; and heating the mixture at a temperature lower than the melting temperature of the particles. the volume of the ceramic particles relative to the total volume of the metal magnetic particles and the ceramic particles; The volume ratio is 3 vol% or more. [Effects of the Invention]

[0015] According to the present invention, a coil component is provided that can improve the reliability of insulation. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a perspective view of a coil component according to an embodiment of the present invention. [Figure 2] FIG. 2 is an exploded perspective view of the coil component of FIG. 1. [Figure 3] FIG. 2 is a cross-sectional view schematically showing a cross section taken along line XX in FIG. [Figure 4] FIG. 4 is an enlarged cross-sectional view schematically showing an enlarged region A of FIG. 3. DETAILED DESCRIPTION OF THE INVENTION

[0017] Various embodiments of the present invention will be described below with reference to the drawings. The same reference numerals are used throughout the drawings to designate components that are common to all the drawings. It should be noted that the surfaces are not necessarily drawn to scale for illustrative purposes. stomach.

[0018] A coil component 1 according to one embodiment of the present invention will be described with reference to FIGS. The coil component 1 is an example of a coil component to which the present invention is applied. The coil component 1 is a laminated inductor. This laminated inductor is incorporated into a power supply line. The present invention can be used as a power inductor and various other inductors. The present invention can be applied to various coil components other than the laminated inductor shown in the figure.

[0019] As shown in the figure, the coil component 1 includes a base 10 and a coil conductor 25 provided in the base 10. and an external electrode 21 provided on the surface of the base 10. and an external electrode 22 provided at a position spaced from the

[0020] The coil component 1 is mounted on a circuit board 2. The circuit board 2 has two land portions 3a , 3b are provided in the coil component 1. The coil component 1 has a pair of the external electrodes 21, 22 and the circuit board 2. The chip may be mounted on the circuit board 2 by joining the corresponding land portion 3 with solder. The circuit board 2 may include the coil component 1 and various electronic components other than the coil component 1. The circuit board 2 can be mounted in various electronic devices. Devices include smartphones, tablets, game consoles, and automotive electrical components. The coil component 1 can be used in a variety of applications, including electronic devices, electronic equipment, and various other electronic devices. It is not limited to what is specified in the specification.

[0021] The base body 10 is formed in a roughly rectangular parallelepiped shape. The base body 10 has a first main surface 10a, a second main surface 10b, a first end surface 10c, a second end surface 10d, a first side surface 10e, and a second side surface 10f. The outer surface of the main body 10 is defined by these six surfaces. The first main surface 10a and the second main surface 10b face each other, the first end surface 10c and the second end surface 10d face each other, and the first side surface 10e and the second side surface 10f face each other. In FIG. 1, the first main surface 10a is located on the upper side of the main body 10, so the first main surface 10a may be referred to as the "upper surface." Similarly, the second main surface 10b may be referred to as the "lower surface." The magnetically coupled coil component 1 is disposed so that the second main surface 10b faces the circuit board 2, and therefore the second main surface 10b is sometimes referred to as the "mounting surface." When referring to the up-down direction of the magnetically coupled coil component 1, the up-down direction in FIG. 1 is used as the reference. In this specification, unless otherwise understood in the context, the "length" direction, "width" direction, and "thickness" direction of the coil component 1 are defined as the "L-axis" direction, "W-axis" direction, and "T-axis" direction in FIG. 1, respectively. The L-axis, W-axis, and T-axis are orthogonal to each other. The coil axis Y extends along the T-direction. For example, the coil axis Y passes through the intersection of the diagonals of the first main surface 10a, which has a rectangular shape in a plan view, and extends in a direction perpendicular to the first main surface 10a.

[0022] In one embodiment of the present invention, the coil component 1 is formed so that the length dimension (dimension in the L-axis direction) is 0.2 to 6.0 mm, the width dimension (dimension in the W-axis direction) is 0.1 to 4.5 mm, and the thickness dimension (dimension in the T-axis direction) is 0.1 to 4.0 mm. These dimensions are merely examples, and the coil component 1 to which the present invention can be applied can have any dimensions as long as they do not deviate from the spirit of the present invention. In one embodiment, the coil component 1 is formed to have a low profile. For example, the coil component 1 is formed so that its width dimension is greater than its thickness dimension.

[0023] 2 and 3, the base 10 has a plurality of stacked magnetic layers. As shown, the base 10 includes a main body portion 20, an upper cover layer 18 provided on the upper surface of the main body portion 20, and a lower cover layer 19 provided on the lower surface of the main body portion 20. The main body portion 20 includes stacked magnetic layers 11 to 16. In the base 10, the upper cover layer 18, magnetic layer 11, magnetic layer 12, magnetic layer 13, magnetic layer 14, magnetic layer 15, magnetic layer 16, magnetic layer 17, and lower cover layer 19 are stacked in this order from top to bottom in FIG. 2.

[0024] Upper cover layer 18 includes four magnetic layers 18a to 18d. In upper cover layer 18, magnetic layer 18a, magnetic layer 18b, magnetic layer 18c, and magnetic layer 18d are stacked in this order from bottom to top in FIG.

[0025] The lower cover layer 19 includes four magnetic layers 19a to 19d. In the lower cover layer 19, the magnetic layer 19a, the magnetic layer 19b, the magnetic layer 19c, and the magnetic layer 19d are stacked in this order from top to bottom in FIG.

[0026] The magnetic layers 11 to 16 are provided with corresponding conductor patterns C11 to C16. These conductor patterns C11 to C16 form a coil conductor 25. The coil conductor 25 has a coil axis Y. The conductor patterns C11 to C16 are formed to extend around the coil axis Y. In the illustrated embodiment, the coil axis Y extends in the T-axis direction, which coincides with the stacking direction of the magnetic layers 11 to 16.

[0027] In another embodiment of the present invention, the magnetic layers 11 to 16 may be stacked in the L-axis direction. In this case, by forming the conductor patterns C11 to C16 on the surfaces of the magnetic layers 11 to 16, the coil axis Y faces the L-axis direction, which is the same as the stacking direction of the magnetic layers 11 to 16. In another embodiment of the present invention, the magnetic layers 11 to 16 may be stacked in the W-axis direction. In this case, by forming the conductor patterns C11 to C16 on the surfaces of the magnetic layers 11 to 16, the coil axis Y faces the L-axis direction, which is the same as the stacking direction of the magnetic layers 11 to 16. It faces the same W-axis direction as the direction of the arrow.

[0028] The coil component 1 includes insulating layers 11 to 16, insulating layers 18a to 18d, and insulating layer 19a. In addition to the insulating layers 11 to 19d, any number of insulating layers may be included as needed. The insulating layer 16, the insulating layers 18a to 18d, and some of the insulating layers 19a to 19d are omitted as appropriate. In FIG. 3, the boundaries between the magnetic layers are shown, but when the present invention is applied, In addition, in the substrate of an actual coil component, the boundaries between the magnetic layers may not be visible.

[0029] The conductor patterns C11 to C16 are formed on the corresponding insulating layers 11 to 16, respectively. The conductive patterns C11 to C16 are formed by printing such as screen printing, plating, etching, Alternatively, the insulating layers 11 to 15 may be formed by any other known method. The vias V1 to V5 are formed at these positions. A through hole is formed at a predetermined position of the edge layer 15, penetrating the insulating layers 11 to 15 in the T-axis direction. The conductive patterns C11 to C16 are formed by filling the through holes with a conductive material. The vias V1 to V5 are made of a metal having excellent conductivity, such as Ag, Pd, Cu, Al, or any of these. Contains alloys of

[0030] In this specification, the conductive patterns C11 to C16 are separated by a gap between adjacent conductive patterns. A region of the substrate 10 is called an inter-conductor region. That is, the inter-conductor region is a partial region of the substrate 10. , which are areas sandwiched between adjacent conductor patterns. In FIG. 3, there are five inter-conductor areas 10 One of the inter-conductor regions 10X is a region between the conductor pattern C11 and the adjacent pattern C12. The other inter-conductor area 10X is between the turn C11 and the adjacent conductor pattern C12. The conductive patterns are arranged between adjacent conductive patterns as shown in FIG.

[0031] The inter-conductor region 10X will be further described with reference to FIG. 4. In FIG. 4, the region A in FIG. Area A is a part of the conductor pattern C12 and the conductor pattern C13. and a part of the inter-conductor region 10X between the conductor pattern C12 and the conductor pattern C13. As shown in the figure, the substrate 10 includes a plurality of metal layers in the inter-conductor region 10X. It contains magnetic particles 31 and a plurality of ceramic particles 32 .

[0032] The metal magnetic particles 31 are particles or powder made of a soft magnetic metal material. The soft magnetic metal materials used are, for example, (1) metallic Fe or Ni, (2) alloyed Fe -Si-Cr, Fe-Si-Al or Fe-Ni, (3) amorphous Fe-Si-Cr -BC or Fe-Si-B-Cr, (4) or particles of a mixture of these materials.

[0033] The average particle size of the metal magnetic particles 31 is, for example, 2 μm to 10 μm. The average particle size of 1 is not limited to the range of 2 μm to 10 μm and can be changed as appropriate. In the above, the "average particle size" of magnetic particles is based on the volume unless otherwise interpreted. The volume-based average particle size of magnetic particles is defined as follows in accordance with JIS Z 8825: The measurement is performed by a laser diffraction / scattering method. A laser diffraction / scattering particle size distribution analyzer (model number: LA- 960) can be used.

[0034] The metal magnetic particles 31 may include two types of metal magnetic particles having different average particle sizes. When the metal magnetic particles 31 include two types of metal magnetic particles having different average particle sizes, The larger average particle size of the metal magnetic particles 31 is, for example, 2 μm to 10 μm, and the metal magnetic particles The smaller average particle size of 31 is, for example, 1 / 20 to 1 / 2 of the larger average particle size. The smaller average particle size of the metal magnetic particles 31 having different average particle sizes is, for example, 0.2 μm to The metal magnetic particles 31 are made of three or more kinds of metals having different average particle diameters. It may also contain magnetic particles.

[0035] An insulating film is provided on the surface of the metal magnetic particle 31. The insulating film on the surface of the metal magnetic particle 31 may be, for example, an oxide film formed by oxidizing the surface of the metal magnetic particle 31. An insulating coating film may be provided on the surface of the metal magnetic particle 31. This coating film may be, for example, a thin film made of or containing silica.

[0036] The ceramic particles 32 are particles or powder made of a ceramic material with an average particle size smaller than that of the metal magnetic particles 31. The ceramic particles 32 are made of a ceramic material with higher electrical resistivity than the metal magnetic particles 31. The ceramic particles 32 are, for example, particles made of silica, alumina, zirconia, or titania, or mixed particles made of a mixture of these. The ceramic particles 32 have higher insulating properties than the metal magnetic particles 31 provided with an insulating film.

[0037] The average particle size of the ceramic particles 32 is, for example, 10 to 50 nm. The average particle size of the ceramic particles 32 may be 1 / 50 or less of the average particle size of the metal magnetic particles 31. The average particle size of the ceramic particles 32 may be 1 / 100 or less of the average particle size of the metal magnetic particles 31. In one embodiment, the average particle size of the ceramic particles 32 may be 1 / 200 or more of the average particle size of the metal magnetic particles 31. The average particle size of the ceramic particles 32 may be 1 / 50 or less and 1 / 200 or more of the average particle size of the metal magnetic particles 31. When the metal magnetic particles 31 include two or more types of metal magnetic particles with different average particle sizes, the average particle size of the ceramic particles 32 is compared to the average particle size of the metal magnetic particles 31 with the largest average particle size among the multiple types of metal magnetic particles 31. In other words, the average particle size of the ceramic particles 32 may be 1 / 50 or less of the average particle size of the metal magnetic particles 31 with the largest average particle size among the multiple types of metal magnetic particles 31.

[0038] In one embodiment of the present invention, the content of ceramic particles 32 relative to the total volume of metal magnetic particles 31 and ceramic particles 32 in inter-conductor region 10X of base 10 is 3 vol% or more in terms of volume ratio. In one embodiment of the present invention, the content of ceramic particles 32 relative to the total volume of metal magnetic particles 31 and ceramic particles 32 in inter-conductor region 10X of base 10 is 15 vol% or less in terms of volume ratio.

[0039] The volume of metal magnetic particles 31 contained in base 10 is obtained by measuring the particle size of each metal magnetic particle that appears in a cross section obtained by cutting base 10 using the laser diffraction scattering method in accordance with JIS Z 8825 mentioned above, and converting the particle size obtained as a result of this measurement into volume. When converting from particle size to volume, each magnetic particle is assumed to be spherical, in consideration of the measurement principle of the laser diffraction scattering method in accordance with JIS Z 8825. The volume of ceramic particles 32 is also measured and calculated in the same way as the volume of metal magnetic particles 31.

[0040] In one embodiment of the present invention, the inter-conductor region 10X is substantially free of atoms of the metal contained in the coil conductor 25. For example, when the conductor patterns C11 to C16 contain a certain metal (e.g., Ag), if the elemental amount of the metal contained in the inter-conductor region 10X is 1% or less of the elemental amount of the metal contained in a predetermined region within the conductor patterns C11 to C16, it can be determined that the inter-conductor region 10X is substantially free of atoms of the metal contained in the coil conductor 25. More specifically, the coil component 1 is cut along its thickness direction (T direction) to expose a cross section including at least one of the conductor patterns C11 to C16 and the inter-conductor region 10X, and energy dispersive X-ray analysis (EDS) is performed on the region of the cross section included in the conductor patterns C11 to C16 and the region included in the inter-conductor region 10X, thereby making it possible to compare the elemental amount of the metal contained in the conductor patterns C11 to C16 with the elemental amount of the metal contained in the inter-conductor region 10X. For example, when the conductor patterns C11 to C16 contain Ag, the conductor pattern C12 in the 1 μm square area A1 and the inter-conductor area 10X in the 1 μm square area A1 are shown in FIG. The amount of Ag element in the 1 μm square area A2 was analyzed by EDS. The count value of the detected peak of Ag element obtained in area 2 is the Ag count value obtained in area A1. If the count value of the detected peak of the element is 1 / 100 or less, the conductor is not included in the inter-conductor region 10X. Metal contained in body patterns C11 to C16 (i.e., metal contained in coil conductor 25) It can be determined that the atoms of the above are substantially absent. , since it does not contain ceramic particles corresponding to the ceramic particles 32 of the above embodiment. Therefore, metal atoms contained in the conductor pattern diffuse into the inter-conductor region. In the inter-conductor area of ​​the substrate in the product, the metal atoms contained in the coil conductor (conductor pattern) In contrast, in the embodiment of the present invention, ceramic is present in the inter-conductor region 10X. Since the conductive patterns C11 to C16 contain 3 vol% or more of the oxide particles 32, the metal Atoms do not diffuse into the inter-conductor region 10X. As a result, the conductor pattern C Therefore, the inter-conductor region of the substrate 10 does not substantially contain metal atoms contained in the conductive layers C11 to C16. The physical properties in region 10X are affected by the metal atoms contained in the conductor patterns C11 to C16. (For example, the metal atoms are not affected by diffusion into the inter-conductor region 10X.) For example, the insulation resistance in the inter-conductor region 10X is determined by the metal contained in the conductor patterns C11 to C16. In other words, the conductive patterns C11 to C16 are not affected by the metal atoms contained therein. does not substantially reduce the insulation resistance value of the inter-conductor region 10X.

[0041] The substrate 10 may contain a binder to strengthen the bonds between the metal magnetic particles 31. The binder contained in the base 10 may be a thermosetting resin with excellent insulating properties, for example. Examples include epoxy resin, phenolic resin, polyimide resin, silicone resin, and polystyrene (P S) resin, high density polyethylene (HDPE) resin, polyoxymethylene (POM) resin, Polycarbonate (PC) resin, polyvinylidene fluoride (PVDF) resin, phenol ( Phenolic resin, polytetrafluoroethylene (PTFE) resin, polybenzo Polyvinyl alcohol (PVA) resin, polyvinyl butyrate (PBO) resin The resin is PVB resin or acrylic resin.

[0042] The substrate 10 has metal magnetic particles 31 and ceramic particles in regions other than the inter-conductor region 10X. The ceramic particles 32 may be included in the regions other than the inter-conductor regions 10X of the substrate 10. The content of the mixed particles 32 is the content of the ceramic particles 32 in the inter-conductor region 10X. For example, the distance between the coil conductor 25 and the coil conductor 26 in the radial direction centered on the Y axis may be smaller than the distance between the coil conductor 25 and the coil conductor 26. In the core region of the substrate 10 on the side, the content of the ceramic particles 32 is set to be equal to that of the inter-conductor region 1 The content can be reduced to less than that in OX. This reduces the metal content in the core region. Since the content of the magnetic particles 31 can be increased, the effective magnetic permeability of the coil component 1 can be improved. It can be done.

[0043] Next, an example of a method for manufacturing the coil component 1 will be described. The coil component 1 is manufactured by the sheet manufacturing method using a magnetic sheet. When manufacturing the component 1, first, an upper laminate, which will become the upper cover layer 18, an intermediate laminate, and The upper laminate is made up of magnetic layers 18a to 18d. The lower laminate is formed by laminating a plurality of magnetic sheets, and the lower laminate is formed by laminating a magnetic layer 19 The intermediate laminate is formed by laminating a plurality of magnetic sheets 19a to 19d. The magnetic layer is formed by stacking a plurality of magnetic sheets that become the magnetic layers 11 to 16. The sheet is made by kneading a particle group including, for example, metal magnetic particles 31 and ceramic particles 32 with a resin. The resulting slurry is placed in a molding die and a specific molding pressure is applied to produce the metal. The resin to be kneaded with the metal magnetic particles 31 and the ceramic particles 32 is, for example, polyvinyl chloride. Resin materials with excellent insulating properties, such as polyvinyl butyral (PVB) resin and epoxy resin, can be used. .

[0044] The intermediate laminate is formed by stacking a plurality of magnetic sheets on which conductor patterns corresponding to the conductor patterns C11 to C16 are formed. Each of the magnetic sheets for the intermediate laminate has a through hole penetrating in the stacking direction, and the conductor patterns corresponding to the conductor patterns C11 to C16 are formed on the magnetic sheets with the through holes formed therein by screen printing or the like. At this time, the metal material constituting each conductor pattern is embedded in the through-hole of the magnetic sheet to form vias. After forming each sheet including conductor patterns C11 to C16, the base film is removed, and the sheets are stacked in order from the sheet including conductor pattern C16 to the sheet including conductor pattern C11 to obtain an intermediate laminate.

[0045] Next, the intermediate laminate prepared as described above is sandwiched between an upper laminate and a lower laminate, and these upper laminate and lower laminate are thermocompression bonded to the intermediate laminate to obtain a main laminate. Next, the main laminate is diced into pieces of desired size using a cutting machine such as a dicing machine or laser processing machine to obtain chip stacks.

[0046] Next, this chip stack is degreased, and the degreased chip stack is heat-treated. The chip stack is heat-treated at a temperature lower than the melting temperature of the ceramic particles 32 contained in the chip stack. The ceramic particles 32 melt at 1000°C or higher. When the ceramic particles 32 are silica, they melt at approximately 1500°C. The chip stack is heat-treated, for example, at 400°C to 900°C for 20 minutes to 120 minutes. The ceramic particles 32 are not oxidized or reduced during the heat treatment of the stack. A material that does not undergo oxidation or reduction reactions at temperatures below 900°C is selected for the ceramic particles 32.

[0047] Next, a conductive paste is applied to both ends of the heat-treated chip stack to form external electrodes 21 and external electrodes 22. Through the above steps, coil component 1 is obtained.

[0048] The coil component 1 may be manufactured by a method known to those skilled in the art other than the sheet manufacturing method, such as a slurry build method or a thin film process. Manufacturing the coil component 1 by a slurry build method or a thin film process makes it easy to make the content of ceramic particles 32 in the inter-conductor region 10X of the base 10 different from the content of ceramic particles 32 in the core region of the base 10, which is located inside the coil conductor 25 in the radial direction centered on the Y axis. For example, by making the content of ceramic particles 32 in the core region of the base 10 less than the content of ceramic particles 32 in the inter-conductor region 10X, the content of metal magnetic particles 31 in the core region can be increased, thereby improving the effective magnetic permeability of the coil component 1.

[0049] The illustrated laminated inductor is an example of a coil component to which the present invention can be applied, but the present invention can be applied to various types of coil components other than laminated inductors. For example, the present invention can also be applied to planar coils.

[0050] The coil component according to the present invention may be manufactured by a compression molding process instead of a lamination process. When manufacturing the coil component 1 by a compression molding process, a particle group including metal magnetic particles 31 and ceramic particles 32 is first kneaded with a binder resin to form a slurry. Next, the slurry is placed in a molding die in which a coil conductor is placed, and molding pressure is applied to obtain a molded body containing the coil conductor inside. Next, the molded body is heat-treated at a temperature lower than the melting temperature of the ceramic particles 32 to obtain the base 10. Next, a conductor paste is applied to the base 10, thereby forming the external electrodes 21 and 22 on the surface of the base 10. In this manner, the coil component 1 is manufactured by the compression molding process. [Example]

[0051] An example of the present invention will be described. First, Fe—Si—Cr (Fe: 92 wt%, Si Metal magnetic particles having a composition of Cr: 3.5 wt%, Cr: 4.5 wt% were prepared. The metal magnetic particles and silica particles as ceramic particles were mixed in the ratio shown in Table 1. The mixed powder was obtained by mixing. Table 1 shows the ratio of the metal magnetic particles and ceramic particles in this mixed powder. The content of the metal magnetic particles and the ceramic particles relative to the total volume of the The ratio is expressed as a volume ratio. Next, this mixed powder is kneaded with polyvinyl butyral to form a slurry. Next, this slurry was formed into a long sheet using a coating machine such as a die coater. Then, by cutting this, multiple rectangular parallelepiped magnetic sheets with a thickness of 8 μm were created. In this way, nine types of magnetic sheets (first magnetic sheet) with different ceramic particle contents were prepared. Nine types of magnetic sheets (No. 1 magnetic sheet to No. 9 magnetic sheet) were prepared in multiple numbers.

[0052] Next, through holes are formed at predetermined positions in the first magnetic sheet using a laser or the like, and then the The through holes are filled with conductive paste containing Ag, and the conductive paste containing Ag is applied to the A predetermined pattern was printed on the magnetic sheet. The first magnetic sheet is formed such that the conductive patterns formed on the different first magnetic sheets are embedded in the through holes. The layers are laminated so that they are electrically connected via the embedded conductors, and then temporarily pressed at 60°C. Similarly, laminates were prepared using each of the second to ninth magnetic sheets. Next, each of these nine types of laminates was cut into individual pieces using a dicing machine. The individual chip stack is degreased and heated at 800°C. After the heat treatment, external electrodes were formed on the evaluation chip, and nine types of evaluation chips were The coil conductors for evaluation (samples A1 to A9) were obtained. The dimensions in the direction are 1.6 mm, 0.8 mm, and 0.8 mm, respectively, and there are 4.5 ta The coil conductor was 100 mm.

[0053] Twenty pieces of each of the samples A1 to A9 were prepared, and the evaluation coils of the samples A1 to A9 were A deflection test was conducted on each of the conductors. The deflection test was carried out as follows. First, the coil conductors for evaluation were mounted on a 0.8 mm thick glass epoxy board. The substrate was attached between a pair of support posts with a radius of 2.5 mm arranged in a circular pattern. The center of the bottom surface of the attached substrate was indented 2.5 mm with an indenter whose tip had a curvature radius of R340. The substrate was bent by pressing it to a depth of 10 mm at a speed of 1 / sec. The test was carried out while monitoring the resistance of the evaluation coil. When the test piece was pressed to a depth of 1 mm, no electrical breakdown occurred and no visible cracks were observed. It was deemed to be a good product.

[0054] The results of the deflection test are shown in Table 1. As shown in Table 1, the ceramic particles For samples A1 to A6 with a content of 15 vol% or less, 20 evaluation pieces were used for each sample. No electrical breakdown or cracks occurred in any of the coil components. Even if the substrate of the coil conductor contains ceramic particles, the content shall not exceed 15 vol%. It was found that the coil component had sufficient flexural strength if the temperature was below 100°C. [Table 1]

[0055] As described above, increasing the content of ceramic particles 32 in the inter-conductor region 10X reduces the flexural strength. Further increasing the content of ceramic particles 32 in the inter-conductor region 10X, for example to 100 vol%, increases the likelihood of delamination during the manufacturing process. This delamination during the manufacturing process is undesirable because it reduces yield. Furthermore, increasing the content of ceramic particles 32 in the inter-conductor region 10X to 100 vol% reduces the inductance of the coil component.

[0056] Next, nine types of magnetic sheets (first magnetic sheet to ninth magnetic sheet) were fabricated in multiples using the same fabrication process as samples A1 to A9. Next, a conductive paste containing Ag was printed in a predetermined pattern on each of two first magnetic sheets. The two first magnetic sheets with printed conductive patterns were stacked so that their conductive patterns faced each other. A predetermined number of first magnetic sheets, each without printed conductive patterns on the top and bottom surfaces of the two first magnetic sheets, were stacked and temporarily pressed at 60°C to obtain a laminate. Similarly, laminates were fabricated using each of the second magnetic sheet to ninth magnetic sheet. Next, each of these nine types of laminates was singulated using a dicing machine. Next, the singulated chip laminates were degreased and subjected to a heat treatment at 800°C. External electrodes were formed on the heat-treated evaluation chips to obtain nine types of evaluation capacitor chips (samples B1 to B9). The dimensions of this evaluation capacitor chip in the L direction, W direction, and T direction are 1.6 mm×0.8 mm×0.8 mm, respectively.

[0057] Furthermore, for each of the evaluation capacitor chips of samples B1 to B9, the voltage applied between the external electrodes was increased stepwise, and the voltage at which a short circuit occurred was measured. The voltage at which this short circuit occurred was divided by the distance between the electrodes, and the value obtained was the withstand voltage of each sample, as summarized in Table 2. [Table 2]

[0058] As shown in Table 2, samples B3 to B5, which contain ceramic particles at 3 vol% or more, For B9, the withstand voltage was 2.0V / μm or more. Higher current coil components are desired. It is desirable that the withstand voltage of the power supply inductor used is 2V / μm or more. As shown, if the content of ceramic particles is 3 vol% or more, the withstand voltage is 2 It was found that a substrate with a thickness of 1000 V / μm or more could be obtained. This makes it possible to obtain coil components with a withstand voltage of 2V / μm or more.

[0059] Next, the effects of the above embodiment will be described. The substrate 10 is made of a ceramic material having higher insulating properties than the metal magnetic particles 31 in the inter-conductor region 10X. Since the base 10 contains silicon particles 32, the volume resistivity in the inter-conductor region 10X of the base 10 can be improved. This allows the insulation resistance between the conductor patterns C11 to C16, i.e., the withstand voltage In particular, when the content of the ceramic particles 32 is 3 vol %, In the above case, a coil component 1 having a high withstand voltage of 2 V / μm or more can be obtained.

[0060] According to the above embodiment, the average particle size of the ceramic particles 32 is equal to the average particle size of the metal magnetic particles 31. Since the ceramic particles 32 are smaller than the particle size, they penetrate into the gaps between the metal magnetic particles 31. Therefore, the volume of the inter-conductor region 10X hardly increases even when the ceramic particles 32 are added. Therefore, according to the above embodiment, the conductors can be formed while suppressing an increase in the size of the inter-conductor region 10X. The volume resistivity of the intermediate region 10X can be improved. is set to 1 / 50 or 1 / 100 of the average particle size of the metal magnetic particles 31, The ceramic particles 32 are likely to enter between the metal magnetic particles 31. The addition of the aramic particles 32 does not substantially increase the dimensions of the inter-conductor region 10X. The volume resistivity can be improved without increasing the dimensions of the interbody region 10X. The average particle size of the mixed particles 32 is smaller than 1 / 200 of the average particle size of the metal magnetic particles 31. Due to the aggregation of the slurry, the ceramic particles 32 enter the gaps between the metal magnetic particles 31. Therefore, the average particle size of the ceramic particles 32 is set to be equal to the average particle size of the metal magnetic particles 31. It is preferable that the particle size is 1 / 200 or more of the average particle size.

[0061] The conductive patterns C11 to C16 contain metal. A part of this metal is in the form of cations. The conductive patterns C11 to C16 are present in the conductive patterns C11 to C16. The metal element (for example, Fe) contained in the metal magnetic particles 31 is oxidized. The electrons released when oxidized and the metal (e.g., Ag) in the conductor patterns C11 to C16 When the cation (Ag+) reacts with the cation (Ag+) in the inter-conductor region 10X, That is, the metal contained in the conductive patterns C11 to C16 is deposited. According to the above embodiment, the ceramic is diffused into the inter-conductor region 10X. The presence of the magnetic particles 32 reduces the contact area between the conductor patterns C11 to C16 and the metal magnetic particles 31 contained in the inter-conductor regions 10X, making it difficult for the metal atoms contained in the conductor patterns C11 to C16 to diffuse into the inter-conductor regions 10X. In one embodiment, the metal atoms contained in the conductor patterns C11 to C16 are substantially absent in the inter-conductor regions 10X. Diffusion of the metal atoms contained in the conductor patterns C11 to C16 into the inter-conductor regions 10X would cause a deterioration in the insulation of the inter-conductor regions 10X. However, according to the above embodiment, the metal atoms contained in the conductor patterns C11 to C16 do not diffuse into the inter-conductor regions 10X, thereby further improving the insulation resistance, i.e., the withstand voltage, of the inter-conductor regions 10X.

[0062] According to the above embodiment, in the inter-conductor region 10X of the base 10, the content of ceramic particles 32 relative to the total volume of the metal magnetic particles 31 and ceramic particles 32 is set to 15 vol% or less in terms of volume ratio, so that it is possible to improve the volume resistivity of the inter-conductor region 10X while suppressing deterioration in the flexural strength of the base 10 due to the addition of ceramic particles 32. The flexural strength of the base 10 including the metal magnetic particles 31 is ensured by the bonding between the metal magnetic particles 31 in the base 10. By setting the content of ceramic particles 32 to 15 vol% or less, the bonding between the metal magnetic particles 31 is not inhibited, and as a result, it is possible to prevent or suppress a decrease in the flexural strength of the base 10.

[0063] According to the above embodiment, the heating in the manufacturing process of the coil component 1 is performed at a temperature lower than the melting temperature of the ceramic particles 32, which prevents distortion of the shape of the base 10 due to the flow of the ceramic particles 32. This prevents a decrease in insulation resistance, i.e., voltage resistance, due to a decrease in the gap between opposing portions of the coil conductor 25.

[0064] According to the above embodiment, the withstand voltage of the coil component 1 can be increased compared to conventional coil components. As a result, even if the distance between opposing portions of the coil conductor 25 is designed to be smaller than the distance between the coil conductors in conventional coil components that do not contain ceramic particles, the same insulation resistance as the conventional coil component can be obtained. This allows the component to be made thinner.

[0065] Compared to information and communication devices such as smartphones, coil components used in automotive electrical equipment are subject to not only large currents but also high voltages. Therefore, coil components used in automotive electrical equipment are often required to have insulation properties that are at least twice as high as those of conventional coil components primarily used in information and communication devices. The coil components according to the above-described embodiments can also be used in applications requiring such high insulation properties.

[0066] The dimensions, materials, and arrangement of each component described in this specification are not limited to those explicitly described in the embodiments, and each component can be modified to have any dimensions, materials, and arrangement that can be included in the scope of the present invention. Furthermore, components not explicitly described in this specification can be added to the described embodiments, and some of the components described in each embodiment can be omitted.

[0067] The inventions described in the claims of the original application of this application are as follows: [1] a substrate including metal magnetic particles having a first average particle size and ceramic particles having a second average particle size smaller than the first average particle size; a coil conductor provided within the base, the coil conductor including a first conductor portion and a second conductor portion provided within the base so as to face the first conductor portion; Equipped with In an inter-conductor region of the base between the first conductor portion and the second conductor portion, the volume ratio of the ceramic particles to the total volume of the metal magnetic particles and the ceramic particles is 3 vol% or more. Coil parts. [2] The content ratio of the ceramic particles to the metal magnetic particles in the inter-conductor region is 15 vol% or less, [1] The coil component according to [1]. [3] the first conductor portion and the second conductor portion are made of a conductive material including a metal, the substrate is substantially free of atoms of the metal in the inter-conductor region; The coil component according to [1] or [2]. [4] The ceramic particles are made of silica, alumina, zirconia, or titania. The coil component according to any one of [1] to [3]. [5] The second average particle size is 1 / 50 or less of the first average particle size. The coil component according to any one of [1] to [4]. [6] The second average particle size is 1 / 200 or more of the first average particle size. [5] The coil component according to [5]. [7] A circuit board comprising the coil component according to any one of [1] to [6]. [8] [7] An electronic component comprising the circuit board described in [7]. [9] A magnetic particle having a first average particle size and a second average particle size smaller than the first average particle size. and preparing a compact containing ceramic particles having a coil conductor disposed therein. The degree, heating the compact at a temperature lower than the melting temperature of the ceramic particles; Equipped with The ceramic particles relative to the total volume of the metal magnetic particles and the ceramic particles The volume ratio of is 3 vol% or more, Manufacturing method of coil parts. [Explanation of symbols]

[0068] 1 Coil parts 10 Base 10X Interconductor Area 21, 22 External electrode 25 Coil conductor 31 Metal magnetic particles 32 Ceramic particles C11~C16 Conductor pattern

Claims

1. A substrate comprising a plurality of metallic magnetic particles and zirconia disposed in the gaps between the plurality of metallic magnetic particles, A coil conductor provided within the base body, including a first conductor portion and a second conductor portion provided within the base body so as to face the first conductor portion, Equipped with, In the interconductor region of the substrate between the first and second conductor portions, the zirconia content relative to the total of the plurality of metallic magnetic particles and zirconia is 3 vol% or more in terms of volume ratio. Coil components.

2. In the interconductor region, there are substantially no metal atoms contained in the coil conductor. The coil component according to claim 1.

3. The aforementioned coil conductor contains a metal element, The amount of the metal element in the interconductor region is 1% or less of the amount of the metal element in the coil conductor. The coil component according to claim 2.

4. In the interconductor region, the zirconia content relative to the total of the plurality of metallic magnetic particles and zirconia is 15 vol% or less in terms of volume ratio. A coil component according to any one of claims 1 to 3.

5. The content of the metallic magnetic particles in the region of the substrate other than the interconductor region is greater than the content of the metallic magnetic particles in the interconductor region. A coil component according to any one of claims 1 to 4.

6. The coil conductor has a conductor pattern that extends around the coil axis, The substrate has a core region located inward from the conductor pattern in the radial direction centered on the coil axis. The content of the metallic magnetic particles in the core region is greater than the content of the metallic magnetic particles in the interconductor region. A coil component according to any one of claims 1 to 4.

7. The zirconia content in the region of the substrate other than the interconductor region is less than the zirconia content in the interconductor region. A coil component according to any one of claims 1 to 6.

8. Zirconia is interposed between some of the plurality of metallic magnetic particles and the first conductive portion. A coil component according to any one of claims 1 to 7.

9. The aforementioned metallic magnetic particles have a thin film containing silica on their surface. A coil component according to any one of claims 1 to 8.

10. The thin film is made of silica. The coil component according to claim 9.

11. The aforementioned metallic magnetic particles are bound together by a binder. A coil component according to any one of claims 1 to 10.

12. The aforementioned binder includes a resin. The coil component according to claim 11.

13. The substrate does not have a visible boundary in the region excluding the interconductor region. A coil component according to any one of claims 1 to 12.

14. Withstand voltage of 2V / μm or higher, A coil component according to any one of claims 1 to 13.

15. A circuit board comprising a coil component according to any one of claims 1 to 14.

16. An electronic component comprising the circuit board described in claim 15.

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