Coil component and method for manufacturing the coil component

Abstract

To provide a coil component that can suppress a decrease in strength even when exposed at high temperature for a long time.SOLUTION: A coil component (11) includes a porous ceramic portion (1) with pores (2), a coil portion (12) embedded inside the porous ceramic portion (1), and external electrodes (13, 14) provided on the outer surface of the porous ceramic portion (1) and electrically connected to the coil portion (12), and the porosity of the porous ceramic portion (1) is 10 volume% or more and 90 volume% or less, and the pores (2) are filled with a cured product (3) of a resin composition containing an alicyclic epoxy resin and an acid anhydride type curing agent.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a coil component and a method for manufacturing a coil component. [Background technology]

[0002] A ferrite foam sintered body with a porosity of 20 to 70% by volume is known as a ferrite material with a low dielectric constant used in electromagnetic wave absorbers, etc. In a coil including such a ferrite foam sintered body containing pores, the self-resonant frequency does not fluctuate even when a direct current is superimposed, but there is a problem in that the impedance is significantly reduced.

[0003] In view of this, a multilayer ceramic electronic component has been proposed in which 40 volume % or more of the pores in a porous ceramic base are filled with resin, as a multilayer ceramic electronic component that exhibits almost no fluctuation in self-resonant frequency even when a small DC current is superimposed and that can suppress the rate of impedance decrease (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-32995 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the strength of an electronic component that uses a ceramic base whose pores are filled with resin depends on the strength of the resin filled in the pores. Therefore, if the electronic component is exposed to a high-temperature environment for a long period of time and the strength of the resin decreases, the electronic component will no longer be able to maintain the desired strength.

[0006] The present invention has been made to solve the above problems, and has an object to provide a coil component that can suppress a decrease in strength even when exposed to high temperatures for a long period of time. [Means for solving the problem]

[0007] The coil component of the present invention is a coil component comprising: a porous ceramic part having pores; a coil part embedded inside the porous ceramic part; and an external electrode provided on the outer surface of the porous ceramic part and electrically connected to the coil part, wherein the porosity of the porous ceramic part is 10 volume % or more and 90 volume % or less, and the pores are filled with a cured product of a resin composition containing an alicyclic epoxy resin and an acid anhydride curing agent.

[0008] The method for manufacturing a coil component of the present invention is characterized by comprising the steps of: preparing a ceramic green sheet containing a ceramic material and a dissipating material; forming a wiring layer on the ceramic green sheet; stacking the ceramic green sheets on which the wiring layer has been formed to produce an unfired laminate; firing the unfired laminate and dissipating the dissipating material to produce a laminate including a porous ceramic portion having pores; and filling the pores of the porous ceramic portion with a resin composition including an alicyclic epoxy resin and an acid anhydride curing agent. Effect of the Invention

[0009] According to the present invention, it is possible to provide a coil component capable of suppressing a decrease in strength even when exposed to high temperatures for a long period of time. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view that illustrates a schematic internal structure of a porous ceramic portion. [Diagram 2] FIG. 2 is a side cross-sectional view that illustrates an example of the internal structure of a coil component that includes a porous ceramic portion. [Diagram 3] FIG. 3 is an exploded perspective view illustrating an example of a laminate constituting the coil component illustrated in FIG. [Figure 4]FIG. 4 is a graph showing the Weibull distribution of the flexural strength of the coil parts produced in Example 4 and Comparative Example 1 after 3000 hours of high temperature exposure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, the coil component and the method for manufacturing the coil component of the present invention will be described. However, the present invention is not limited to the following configurations and aspects, and can be appropriately modified and applied within the scope of the present invention. Note that the present invention also includes a combination of two or more of the individual preferred configurations and aspects of the present invention described below.

[0012] <Coil parts> The coil component of the present invention comprises a porous ceramic part having a coil part embedded therein, which is formed by stacking and firing ceramic green sheets on which wiring layers are formed. In particular, the porous ceramic part is characterized in that the pores are filled with a cured product of a resin composition containing an alicyclic epoxy resin and an acid anhydride curing agent.

[0013] First, the porous ceramic portion will be described with reference to FIG. FIG. 1 is a cross-sectional view that illustrates a schematic internal structure of a porous ceramic portion. 1, a plurality of pores 2 are formed inside and on the surface of the porous ceramic portion 1, and the pores 2 are filled with a cured resin composition 3. The average pore diameter of the pores 2 is preferably 1 μm or more and 10 μm or less, and more preferably 2 μm or more and 6 μm or less. The average pore diameter can be measured by observation with a SEM (electron microscope).

[0014] The porous ceramic portion is formed so that the porosity is 10% by volume or more and 90% by volume or less. If the porosity is less than 10% by volume, the decrease in the dielectric constant of the porous ceramic portion is insufficient, and if it exceeds 90% by volume, it is difficult to manufacture the porous ceramic portion. The porosity is preferably 10% by volume or more and 50% by volume or less. The porosity can be calculated by the method described in the Examples below.

[0015] The ceramic material constituting the porous ceramic portion may be a magnetic material such as a ferrite material, a non-magnetic material such as a glass ceramic material, or a mixed material of these magnetic and non-magnetic materials. The ceramic material is preferably a ferrite material, and more preferably a Ni-Zn-Cu based ferrite material.

[0016] In the coil component of the present invention, the pores of the porous ceramic portion are filled with a cured product of a resin composition containing an alicyclic epoxy resin and an acid anhydride curing agent. Examples of the alicyclic epoxy resin include cycloalkene oxide type resins, specifically 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, bicyclohexyl-3,3'-diepoxide, 3,4:7,8-diepoxybicyclo[4.3.0]nonane, 4,5:10,11-diepoxytetracyclo[6.5.1.0 2,7 .0 6,13 ]Tetradecane, 4,5:10,11-diepoxypentacyclo[6.5.1.1 3,6 .0 2,7 .0 9,13 ]pentadecane, etc. These alicyclic epoxy resins may be used alone or in combination of two or more. As the alicyclic epoxy resin, 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate is preferred. The content of the alicyclic epoxy resin in the resin composition is preferably 35% by weight or more and 55% by weight or less based on the total weight of the alicyclic epoxy resin and the acid anhydride curing agent.

[0017] The resin composition may contain other epoxy resins in addition to the alicyclic epoxy resins, such as bisphenol A epoxy resins, bisphenol F epoxy resins, and hydrogenated bisphenol A epoxy resins. When other epoxy resins are contained, the proportion of the alicyclic epoxy resin is preferably 25% by weight or more and 75% by weight or less based on the total weight of the alicyclic epoxy resin and the other epoxy resin.

[0018] As the acid anhydride curing agent, for example, at least one selected from the group consisting of methyltetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride, dodecenylsuccinic anhydride, methylhexahydrophthalic anhydride, and hexahydrophthalic anhydride is preferably used, and more preferably, a mixture of methylhexahydrophthalic anhydride and hexahydrophthalic anhydride.

[0019] The content of the acid anhydride curing agent in the resin composition is preferably 45% by weight or more and 65% by weight or less based on the total weight of the alicyclic epoxy resin and the acid anhydride curing agent. The resin composition may further contain a curing accelerator, an antioxidant, a polymerization initiator, a plasticizer, an antistatic agent, a flame retardant, an antifoaming agent, a viscosity modifier, and the like.

[0020] The cured product of the resin composition containing the alicyclic epoxy resin and the acid anhydride curing agent has a high glass transition temperature and high heat resistance, so that the use of the cured product of the resin composition containing the alicyclic epoxy resin and the acid anhydride curing agent as the resin to fill the pores can suppress the decrease in strength of the coil component when exposed to high temperatures.

[0021] In the coil component of the present invention, the glass transition temperature (Tg) of the cured product is preferably 200° C. or higher. If the Tg is less than 200° C., the strength of the coil component may be insufficient when exposed to high temperatures for a long period of time. It is more preferably 200° C. or higher and 300° C. or lower. The Tg of the cured product is a value measured in accordance with JIS K7121.

[0022] In the coil component of the present invention, the filling rate of the cured material relative to the volume of the pores is preferably 30% by volume or more. If the filling rate is less than 30% by volume, the bending strength of the coil component may deteriorate. More preferably, the filling rate is 40% by volume or more and 90% by volume or less.

[0023] The filling rate of the cured resin composition relative to the pore volume can be calculated by the following method. The volume of the filled cured product is calculated from the change in weight of the porous ceramic part before and after filling with the resin composition and the specific gravity of the cured product. The volume of the porous ceramic part is then calculated from the dimensional measurements made with a micrometer, and multiplied by the porosity to obtain the pore volume in the porous ceramic part. The value obtained by dividing the volume of the cured product by the pore volume is the filling ratio of the cured product to the pore volume (volume %). Filling rate of hardened material (volume%) = [(volume of hardened material) / (volume of pores)] x 100 The volume of the filled hardened material can also be determined from the weight loss rate obtained by TG-DTA of the finished coil component and the density of the hardened material.

[0024] Next, an example of the configuration of the coil component of the present invention will be described with reference to FIGS. FIG. 2 is a side cross-sectional view that illustrates an example of the internal structure of a coil component that includes a porous ceramic portion. FIG. 3 is an exploded perspective view showing a schematic example of a laminate constituting the coil component shown in FIG. 2, the coil component 11 has a structure in which a coil portion 12 is embedded inside a porous ceramic portion 1, and external electrodes 13 and 14 are provided on the outer surface of the porous ceramic portion 1. The external electrodes 13 and 14 are electrically connected to the coil portion 12 through via portions 15 and 16, respectively.

[0025] Fig. 2 is a side view showing a schematic example of an internal structure of the porous ceramic portion 1 constituting the coil component 11, and does not strictly represent the actual shape, connections, etc. As will be described later with reference to Fig. 3, the coil conductors 22 constituting the coil portion 12 are connected through via conductors 23, and the via conductors 23 are connected to each other.

[0026] 3, the porous ceramic part 1 is configured by laminating a plurality of porous ceramic sheets 21a and 21b. The porous ceramic sheet 21a is provided with a via conductor 23. The porous ceramic sheet 21b is provided with a coil conductor 22 and a via conductor 23. The coil conductor 22 and the via conductor 23 are laminated together with the porous ceramic sheet 21a and the porous ceramic sheet 21b.

[0027] <Manufacturing method of coil parts> Next, a method for manufacturing the coil component will be described. This method for manufacturing the coil component is also a method for manufacturing the coil component of the present invention.

[0028] First, one embodiment of a process for preparing a ceramic green sheet containing a ceramic material and a dissipating material will be described. As the ceramic material, for example, a magnetic material such as a ferrite material, a non-magnetic material such as a glass ceramic material, or a mixed material of these magnetic and non-magnetic materials can be used. In the manufacturing method of the present invention, the ceramic material is preferably a ferrite material. As the ferrite material, for example, a Ni-Zn-Cu ferrite material (mixed oxide powder) can be obtained by wet mixing oxides of iron, nickel, zinc, and copper, pulverizing the mixture with a ball mill, drying, and calcining.

[0029] The vanishing material is not particularly limited as long as it is vanishing from the porous ceramic part by firing, but it is preferable to use a spherical polymer that has a large surface area and shape retention, and has excellent adhesion to the binder. By adopting a spherical polymer, it is possible to reduce the proportion of the binder and increase the proportion of the vanishing material. As the vanishing material, resin balls or the like having an average particle diameter of 1 μm or more and 10 μm or less are preferable. The average particle diameter of the vanishing material is more preferably 4 μm or more and 6 μm or less. Examples of the composition of the vanishing material include cross-linked polymethylmethacrylate, polystyrene, polyethylene, polypropylene, etc., and cross-linked polymethylmethacrylate is preferable.

[0030] A ceramic green sheet can be obtained by adding and mixing the above ceramic material and the dispersing material with a binder, an organic solvent, a dispersing agent, etc., and forming the resulting mixture into a sheet of a predetermined thickness by a doctor blade method, etc. The amount of the dispersing material is adjusted so that the porosity of the porous ceramic part is the desired value.

[0031] Next, one embodiment of a process for forming a wiring layer on a ceramic green sheet will be described. As described later, ceramic green sheets on which wiring layers are formed are stacked and fired, so that the wiring layers form the coil portion and via portion of the coil component. First, a ceramic green sheet containing the ceramic material and the lost material obtained in the above process is laser processed at a predetermined location to form a via hole. A conductive paste such as Ag paste is printed on the ceramic green sheet having the via hole, and the conductive paste is filled in the via hole. This conductive paste becomes a via conductor. Furthermore, a conductive paste that becomes a conductor pattern for winding a coil of a predetermined shape is printed. This conductive paste becomes a coil conductor. By drying the ceramic green sheet after printing the conductive paste, a wiring layer can be formed on the ceramic green sheet.

[0032] Next, an embodiment of a process for producing an unfired laminate by stacking the ceramic green sheets on which the wiring layers have been formed will be described. Ceramic green sheets on which coil conductors and via conductors are formed are laminated so that after singulation, a coil portion having a rotation axis parallel to the mounting surface is formed inside the laminate, and ceramic green sheets on which via conductors that will become via portions are further laminated on top of and pressed together. The pressed body is then cut to a predetermined size and singulated to produce an unfired laminate.

[0033] The process of firing the unfired laminate and removing the removed material to produce a laminate having a porous ceramic portion with pores can be performed by firing the individualized unfired laminate at a predetermined temperature for a predetermined time. The removed material contained in the ceramic green sheet is removed by firing, and the shape of the removed material becomes the shape of the pores of the porous ceramic portion almost as it is.

[0034] Next, one embodiment of the step of filling the pores of the porous ceramic portion with a resin composition containing an alicyclic epoxy resin and an acid anhydride curing agent will be described. First, a resin composition containing an alicyclic epoxy resin and an acid anhydride curing agent is prepared. The alicyclic epoxy resin and the acid anhydride curing agent may be the same as those described above for the coil component. In addition to the alicyclic epoxy resin and the acid anhydride curing agent, the resin composition may contain other epoxy resins, curing accelerators, antioxidants, polymerization initiators, plasticizers, antistatic agents, flame retardants, defoamers, viscosity adjusters, and the like.

[0035] The fired laminate is immersed in the resin composition for a predetermined time to fill the pores of the porous ceramic part with the resin composition. The immersion is preferably performed under reduced pressure or in a vacuum. By changing the immersion time in the resin composition, the filling rate of the resin composition in the pores can be adjusted.

[0036] After the step of filling the pores of the porous ceramic part with the resin composition, the laminate is heat-treated to cure the resin composition filled in the pores 2. The heat treatment can be carried out, for example, at 190°C or higher and 250°C or lower for 0.5 hours or longer and 24 hours or shorter. The heat treatment is preferably carried out at 200°C or higher and 250°C or lower.

[0037] There are no particular limitations on the method for forming the external electrodes, and any known forming method can be used. For example, it is preferable to (1) apply a conductive paste to the outer surface of the fired laminate and bake the conductive paste to form an external electrode, or (2) fill the pores of the porous ceramic part with the resin composition and then form an external electrode on the outer surface of the porous ceramic part.

[0038] In the above method (1), specifically, first, an unfired laminate is degreased under a predetermined condition in the air, and then fired at a predetermined temperature to form a laminate. Then, a conductive paste containing conductive particles such as Cu, Ni, Ag, and a glass ceramic material is applied to the outer surface of the fired laminate by immersion, coating, or the like. Next, the laminate to which the conductive paste has been applied is baked at a predetermined temperature. As a result, the conductive paste is baked to form a base electrode layer connected to the via part. Then, a resin composition is filled into the pores of the porous ceramic part and hardened, and then a first plating layer formed by Ni plating and a second plating layer formed by Sn plating are sequentially laminated on the surface of the base electrode layer to form an external electrode.

[0039] Specifically, in the above method (2), a fired laminate is first formed in the same manner as in method (1). Then, a resin composition is filled into the pores of the porous ceramic part and cured. Thereafter, a conductive paste containing conductive particles such as Cu, Ni, Ag, etc. and a thermosetting resin is applied by coating or the like and cured to form a base electrode layer. A first plating layer made of Ni plating and a second plating layer made of Sn plating are sequentially laminated on the surface of the base electrode layer to form an external electrode. EXAMPLES

[0040] Hereinafter, examples will be given that more specifically disclose the coil component of the present invention and the manufacturing method of the coil component of the present invention, but the present invention is not limited to these examples. The filling rate of the cured resin composition relative to the pore volume was calculated based on the above-mentioned calculation method.

[0041] <Porosity of porous ceramic part> The porosity of the porous ceramic portion was calculated by the following method. The ceramic green sheet containing the lost material was fired at 905°C for 150 minutes to obtain a porous ceramic sheet. A cross section of the obtained porous ceramic sheet was formed using an ion milling device. A backscattered electron image of the cross section of the porous ceramic sheet was obtained using an electron microscope, and the backscattered electron image was binarized using image analysis software WinROOF to calculate the area ratio of the pores to the cross section of the porous ceramic sheet, which was defined as the porosity (volume %) of the porous ceramic part.

[0042] [Examples 1 to 7] (Preparation of ceramic materials) Fe2O3, NiO, ZnO, and CuO powders were prepared and weighed to obtain the desired mixing ratio, and the weighed materials were placed in a ball mill together with PSZ media and wet mixed and ground. The slurry was discharged from the ball mill, dried, and then calcined at 800°C for 2 hours.

[0043] (Preparation of Ceramic Green Sheets) A predetermined amount of resin balls made of cross-linked polymethylmethacrylate (average particle diameter 5 μm, manufactured by Sekisui Chemical Co., Ltd., spherical fine particle polymer (Techpolymer)) was added to this calcined product, and the mixture was mixed and pulverized in a ball mill together with a polyvinyl butyral binder, ethanol and toluene as organic solvents, and PSZ balls. The resulting mixture was molded into a sheet of a predetermined thickness using a doctor blade method, and punched out to a predetermined size to produce a ceramic green sheet. The amount of resin balls added was adjusted so that the porosity of the porous ceramic after firing was 10 volume % (Example 1), 30 volume % (Examples 2 to 5), 50 volume % (Example 6), and 90 volume % (Example 7).

[0044] (Formation of wiring layer and fabrication of laminate) Next, a laser was irradiated to predetermined locations of the prepared ceramic green sheets to form via holes, and Ag paste was printed to fill the via holes and form coil conductors. The ceramic green sheets with the coil conductors formed were stacked in a predetermined order, and a predetermined number of ceramic green sheets with via conductors printed on them were placed above and below them, and the sheets were pressed together to produce an unfired laminate block. The unsintered laminated block was cut into individual pieces and sintered at 900°C for two hours to obtain the coil component body. The end faces of the obtained body were coated with Ag paste containing glass components and baked at 800°C to form the base electrode layer for the external electrodes.

[0045] (Filling and curing of resin composition) Next, a resin composition was prepared containing 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate as an alicyclic epoxy resin and a mixture of 4-methylhexahydrophthalic anhydride and hexahydrophthalic anhydride as an acid anhydride curing agent. The weight ratio of the resin composition was 45% by weight of the alicyclic epoxy resin and 55% by weight of the acid anhydride curing agent. The element on which the above-mentioned base electrode layer was formed was immersed in this resin composition for a predetermined time and held under vacuum to fill the pores with the resin. In addition, for an element with a porosity of the porous ceramic part of 30% by volume, samples with different filling rates of the resin composition were prepared by changing the immersion time. After filling with the resin composition, the filled resin was cured by heat treatment at a maximum temperature of 200°C. After the resin was cured, a Ni plating layer and a Sn plating layer were successively formed on the base electrode layer by electrolytic plating to form external electrodes, thereby obtaining the coil components of Examples 1 to 7. The porosity of the porous ceramic portion of the obtained coil components and the filling rate of the cured product are shown in Table 1. Furthermore, the Tg of the cured product obtained by curing the resin composition was measured and found to be 216°C.

[0046] [Comparative Example 1] Instead of the resin composition used in Examples 1 to 7, a resin mixture consisting of bisphenol A type liquid epoxy resin, butyl glycidyl ether, and m-phenylenediamine / 4,4'-methylenedianiline as an amine-based curing agent was prepared. An element having a porous ceramic part with a porosity of 30% by volume was immersed in this resin mixture to fill the pores with resin, and a thermal curing treatment was performed at 180°C. A plating treatment was performed in the same manner as in Examples 1 to 7 to produce a coil component. The porosity of the porous ceramic part of the obtained coil component and the filling rate of the cured product are shown in Table 1.

[0047] [Table 1]

[0048] <Evaluation of bending strength after high temperature exposure> The coil parts obtained in Example 4 and Comparative Example 1 were left in a thermostatic chamber PH-202 manufactured by Espec Corporation set at 150°C or 175°C, and after 3000 hours, they were removed and their flexural strength was measured using a three-point bending tester. FIG. 4 is a graph showing the Weibull distribution of the flexural strength of the coil parts produced in Example 4 and Comparative Example 1 after 3000 hours of high temperature exposure. Table 2 shows the value of the flexural strength where the probability (F(t)) obtained from the Weibull distribution in FIG. 4 is 1.0%. F(t) indicates the degree of unreliability, and (F(t)) of 1.0% means a degree of reliability of 99.0%.

[0049] [Table 2]

[0050] At an exposure temperature of 150°C, the flexural strength at a probability of 1.0% was 32N in Comparative Example 1, whereas it was 51N in Example 4, an improvement of approximately 60%. This tendency was similar at 175°C. The reason for this is that alicyclic epoxy resins have many highly rigid cyclic structures in the crosslinked structure of the cured product, so that the thermal motion of the molecular chains is smaller than that of bisphenol A epoxy resins, and the molecular chains are less likely to be cut by active oxygen. The fact that alicyclic epoxy resins are less susceptible to thermal motion can also be seen from the fact that the glass transition temperature of the cured product is approximately 216°C, which is higher than the glass transition temperature of bisphenol A epoxy (around 150°C). [Explanation of symbols]

[0051] 1 Porous ceramic part 2. Stoma 3. Cured product of resin composition 11 Coil parts 12 Coil section 13, 14 External electrode 15, 16 Via section 21a, 21b Porous ceramic sheet 22 Coil conductor 23 Via conductor

Claims

1. A porous ceramic portion having pores; a coil portion embedded inside the porous ceramic portion; an external electrode provided on an outer surface of the porous ceramic portion and electrically connected to the coil portion, The porosity of the porous ceramic portion is 10 volume % or more and 90 volume % or less, the pores are filled with a cured product of a resin composition including an alicyclic epoxy resin and an acid anhydride curing agent, A coil component, characterized in that the glass transition temperature of the cured product is 200°C or higher.

2. 2. The coil component according to claim 1, wherein the alicyclic epoxy resin contains at least 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate.

3. 3. The coil component according to claim 1, wherein the acid anhydride-based curing agent is at least one selected from the group consisting of methyl tetrahydrophthalic anhydride, methyl end methylene tetrahydrophthalic anhydride, methyl butenyl tetrahydrophthalic anhydride, dodecenyl succinic anhydride, methyl hexahydrophthalic anhydride, and hexahydrophthalic anhydride.

4. 4. The coil component according to claim 1, wherein the acid anhydride-based curing agent is a mixture of methylhexahydrophthalic anhydride and hexahydrophthalic anhydride.

5. The coil component according to any one of claims 1 to 4, wherein a filling rate of the cured material with respect to a volume of the pores is 30 volume % or more.

6. The coil component according to any one of claims 1 to 5, wherein the resin composition contains 35% by weight or more and 55% by weight or less of the alicyclic epoxy resin.

7. The coil component according to any one of claims 1 to 6, wherein the porosity of the porous ceramic portion is 10 volume % or more and 30 volume % or less.

8. Providing a ceramic green sheet including a ceramic material and a dissipating material; forming a wiring layer on the ceramic green sheet; a step of stacking the ceramic green sheets on which the wiring layers are formed to produce an unfired laminate; a step of firing the unsintered laminate and removing the loss material to produce a laminate having a porous ceramic portion having pores; filling the pores of the porous ceramic portion with a resin composition containing an alicyclic epoxy resin and an acid anhydride curing agent; The glass transition temperature of the cured product of the resin composition is 200° C. or higher, The method for manufacturing a coil component, wherein the porosity of the porous ceramic portion is 10 volume % or more and 90 volume % or less.

9. 9. The method for producing a coil component according to claim 8, further comprising the steps of: applying a conductive paste to an outer surface of the laminate; baking the conductive paste to form external electrodes; and then filling the laminate with the resin composition.

10. The method for producing a coil component according to claim 8 , further comprising the steps of: filling the pores of the porous ceramic portion with the resin composition; and then forming an external electrode on an outer surface of the porous ceramic portion.

11. The method for producing a coil component according to any one of claims 8 to 10, wherein the resin composition contains 35% by weight or more and 55% by weight or less of the alicyclic epoxy resin.

12. The method for manufacturing a coil component according to any one of claims 8 to 11, wherein the porosity of the porous ceramic portion is 10 volume % or more and 30 volume % or less.

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