Inductor Components

Abstract

To provide an inductor component that can improve quality and yield.SOLUTION: An inductor component includes a base assembly made of insulating material and a coil arranged within the base assembly and wound spirally along an axis. The insulating material is composed of a base material made of amorphous material containing B, Si, and O and a crystalline filler. The base assembly includes a high-concentration phosphorus-containing portion at a position along the coil. The concentration of P in the base material at the high-concentration phosphorus-containing portion is higher than the concentration of P in the base material at the central portion of the base assembly.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to inductor components. [Background technology]

[0002] A conventional inductor component is described in Japanese Patent Application Laid-Open No. 2018-131353 (Patent Document 1). This inductor component includes an element body containing a glass-based insulating material and a coil disposed within the element body.

[0003] However, when an inductor component contains a glass-based insulating material, the strength of the inductor component decreases, and cracks may occur in the inductor component element due to impacts during mounting or stress caused by board deflection. To address this problem, for example, a crystalline filler is added to the glass-based insulating material. In Patent Document 1, the element portion is a glass ceramic containing a glass-based insulating material and a crystalline filler. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-131353 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the above-mentioned conventional inductor components, adding a crystalline filler to the element body suppresses the softening of the glass-based material, which can lead to poor bonding (peeling) between the element body and the coil, and can also increase the difference in linear expansion coefficient between the element body and the coil, which can lead to cracks in the element body near the coil due to stress caused by the difference in linear expansion coefficient. In particular, when a quartz filler, which is effective in lowering the dielectric constant of glass-based insulating materials, is used, the softening of the glass-based material is further suppressed, which can further reduce the bondability between the element body and the coil.

[0006] Therefore, an object of the present disclosure is to provide an inductor component that can improve quality and increase yield. [Means for solving the problem]

[0007] In order to solve the above problems, an inductor component according to one aspect of the present disclosure comprises: an element body made of an insulating material; a coil disposed within the element body and wound helically along the axis; Equipped with the insulating material contains a base material made of an amorphous material containing B, Si, and O, and a crystalline filler; the element body includes a high-concentration phosphorus-containing portion located along the coil, The concentration of P in the base material in the high-concentration phosphorus containing portion is higher than the concentration of P in the base material in the central portion of the element body.

[0008] Here, the central portion of the element body refers to the portion within a radius of 10 μm from the center point of the cross section of the element body that includes the center point of the element body. For example, if the element body is approximately cubic, the central point is the point where the length, width, and height of the element body are all half. If the portion within the radius of 10 μm is occupied by a coil and the concentration of P in the base material cannot be detected, the central portion is expanded to the portion within a radius of 20 μm from the center point. In addition, the P concentration in the base material is the proportion of P when the base material is used as the reference, and is the element concentration when an SEM (scanning electron microscope) image of the base material part of the element body is subjected to elemental analysis using EDX (energy dispersive X-ray spectroscopy). Furthermore, in this specification, when "B," "Si," "O," or "P" is written, it refers to the element represented by the symbol, and "including the element" does not mean including the element itself, but including the element as a compound.

[0009] According to the above aspect, the element body includes a high-concentration phosphorus-containing portion located along the coil, and the P concentration in the base material in the high-concentration phosphorus-containing portion is higher than the P concentration in the base material in the center of the element body. This allows the high-concentration phosphorus-containing portion (phosphorus-containing glass) to soften easily, ensuring close contact between the coil and the high-concentration phosphorus-containing portion along the coil during firing. This improves the bond between the element body and the coil and prevents peeling between the element body and the coil. Furthermore, since the high-concentration phosphorus-containing portion (phosphorus-containing glass) has a large linear expansion coefficient, it is possible to reduce the difference in linear expansion coefficient between the coil and the high-concentration phosphorus-containing portion along the coil, thereby preventing cracks in the element body near the coil due to stress caused by the difference in linear expansion coefficient between the element body and the coil inside the product after firing. This allows for improved quality of inductor components and improved yield of inductor components.

[0010] Preferably, in one embodiment of the inductor component, the high concentration phosphorus-containing portion is present at a position within 10 μm from the surface of the coil.

[0011] According to the embodiment, the high-concentration phosphorus containing portion can cover the coil in a film-like manner, and the volume of the high-concentration phosphorus containing portion in the element body can be relatively reduced, thereby reducing the dielectric constant of the element body, reducing dielectric loss, and improving coil characteristics.

[0012] Preferably, in one embodiment of the inductor component, the concentration of P in the base material in the high-concentration phosphorus-containing portion is 1.5 times or more the concentration of P in the base material in the central portion of the element body.

[0013] According to the embodiment, the P concentration in the base material in the high-concentration phosphorus-containing portion can be relatively increased, the bondability between the element body and the coil can be further improved, and the difference in linear expansion coefficient between the element body and the coil can be further reduced.

[0014] Preferably, in one embodiment of the inductor component, the coil has first and second coil wirings stacked adjacent to each other in the axial direction, the high-concentration phosphorus-containing portion includes a first high-concentration phosphorus-containing portion covering at least a part of a surface of the first coil wiring facing the second coil wiring, and a second high-concentration phosphorus-containing portion covering at least a part of a surface of the second coil wiring facing the first coil wiring, The element body has an interlayer portion located between the first high-concentration phosphorus containing portion and the second high-concentration phosphorus containing portion, and a concentration of P in the base material in the interlayer portion is lower than a concentration of P in the base material in the first high-concentration phosphorus containing portion and is also lower than a concentration of P in the base material in the second high-concentration phosphorus containing portion.

[0015] According to the embodiment, the P concentration in the base material in the interlayer portions of the element body can be made relatively low, thereby reducing the dielectric constant of the element body, reducing dielectric loss, and improving coil characteristics.

[0016] Preferably, in one embodiment of the inductor component, the coil partially contains an amorphous material containing B, Si, and O.

[0017] Here, the coil partially containing the amorphous material means that the amorphous material is not completely embedded in the coil, and part of the amorphous material is exposed from the outer circumferential surface of the coil.

[0018] According to the embodiment, the coil partially contains amorphous material. Therefore, it is believed that liquid phase sintering progresses in the sintering step of the manufacturing method of the inductor component to the extent that the amorphous material reaches the surface of the coil from the inside. This further improves the smoothness of the coil and enables a higher Q at high frequencies.

[0019] Furthermore, high-frequency current flows preferentially along the surface of the coil due to the skin effect. Therefore, if the coil partially contains amorphous material, the surface area of ​​the coil increases and the electrical resistance decreases. This makes it possible to further increase the Q factor at high frequencies.

[0020] Preferably, in one embodiment of the inductor component, the coil is completely encapsulated in an amorphous material containing B, Si, and O.

[0021] Here, the phrase "the coil completely contains the amorphous material" means that the amorphous material is completely embedded in the coil and is not exposed from the outer circumferential surface of the coil.

[0022] According to the embodiment, when the coil completely encloses the amorphous material, an interface between the coil and the amorphous material is formed within the coil. This increases the surface area of ​​the coil, and the skin effect at high frequencies reduces electrical resistance. Therefore, the inductor component according to this embodiment can further increase the Q factor at high frequencies.

[0023] Preferably, in one embodiment of the inductor component, the crystalline filler includes any of Al, Si, Ti, Zr, Ca, Mg, Fe, and Mn.

[0024] According to the embodiment, the strength of the inductor component can be further improved.

[0025] Preferably, in one embodiment of the inductor component, the crystalline filler is quartz particles or crystalline silica particles.

[0026] According to the embodiment, the dielectric constant of the element body can be reduced, and the characteristics of the inductor component can be improved.

[0027] Preferably, in one embodiment of the inductor component, the content of the crystalline filler in the high-concentration phosphorus containing portion is 80% or more and 120% or less of the content of the crystalline filler in the central portion of the element body.

[0028] According to the embodiment, the content of the crystalline filler does not decrease in the high-concentration phosphorus containing portion, so that the amount of the crystalline filler can be secured in the high-concentration phosphorus containing portion, and the strength of the element body can be secured.

[0029] On the other hand, if the content of crystalline filler in the high-concentration phosphorus-containing portion is high, softening of the high-concentration phosphorus-containing portion is suppressed, which may reduce the bondability between the element body and the coil. In addition, the difference in linear expansion coefficient between the high-concentration phosphorus-containing portion (element body) and the coil increases, which may cause cracks in the element body near the coil due to stress caused by the difference in linear expansion coefficient. However, because the concentration of P in the base material of the high-concentration phosphorus-containing portion is high, it is possible to promote softening of the high-concentration phosphorus-containing portion and improve the bondability between the element body and the coil, while reducing the difference in linear expansion coefficient between the high-concentration phosphorus-containing portion (element body) and the coil and suppress cracks in the element body near the coil.

[0030] Therefore, it is possible to realize an inductor component with a high yield while ensuring the strength of the element body.

[0031] Preferably, in one embodiment of the inductor component, The coil has a plurality of coil wires stacked along the axis, In a cross section including the axis, the concentration distribution of P in the base material in the high-concentration phosphorus containing portion that covers at least a portion of the periphery of one coil wiring is different from the concentration distribution of P in the base material in the high-concentration phosphorus containing portion that covers at least a portion of the periphery of another coil wiring.

[0032] Here, different concentration distributions means that, for example, the thickness and concentration of a high-concentration phosphorus-containing portion on the inner diameter side, outer diameter side, or inter-wire side of a certain coil wiring are different from the thickness and concentration of a high-concentration phosphorus-containing portion on the corresponding inner diameter side, outer diameter side, or inter-wire side of another coil wiring. According to the embodiment, in a cross section including the axis, the P concentration distribution in the base material of the high-concentration phosphorus-containing portion becomes random and irregular due to different coil wirings, which improves the bonding strength between the element body and the coil uniformly throughout the inductor component and reduces the difference in linear expansion coefficient between the element body and the coil. [Effects of the Invention]

[0033] According to an inductor component according to one aspect of the present disclosure, it is possible to improve quality and increase yield. [Brief explanation of the drawings]

[0034] [Figure 1] 1 is a transparent perspective view showing a first embodiment of an inductor component. [Figure 2] FIG. 2 is an exploded perspective view of the inductor component. [Figure 3] 3 is a plan view showing the layer including the coil wiring in the bottom layer of FIG. 2. FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. [Figure 5] FIG. 5 is an enlarged view of a portion of FIG. [Figure 6A] 1A to 1C are explanatory diagrams illustrating a method for manufacturing an inductor component. [Figure 6B] 1A to 1C are explanatory diagrams illustrating a method for manufacturing an inductor component. [Figure 6C] 1A to 1C are explanatory diagrams illustrating a method for manufacturing an inductor component. [Figure 7] FIG. 10 is a plan view of some layers showing a second embodiment of an inductor component.

[0035] Hereinafter, an inductor component according to one aspect of the present disclosure will be described in detail with reference to the illustrated embodiments. Note that the drawings include some schematic views and may not reflect actual dimensions or proportions.

[0036] First Embodiment (composition) Fig. 1 is a perspective view showing a first embodiment of an inductor component. Fig. 2 is an exploded perspective view of the inductor component. Fig. 3 is a plan view showing a layer including the bottommost coil wiring of Fig. 2. Fig. 4 is a cross-sectional view taken along line IV-IV of Fig. 1. Fig. 5 is an enlarged view of a portion A of Fig. 4.

[0037] 1 and 2, the inductor component 1 includes an element body 10, a coil 20 disposed within the element body 10, and a first external electrode 30 and a second external electrode 40 electrically connected to the coil 20. In FIG. 1, the element body 10 is depicted as transparent so that the internal structure of the element body 10 can be easily understood. Also, in FIG. 1, the high-concentration phosphorus-containing portion 101 is not depicted so that the internal structure of the element body 10 can be easily understood.

[0038] The inductor component 1 is electrically connected to wiring on a circuit board (not shown) via first and second external electrodes 30, 40. The inductor component 1 is used, for example, as an impedance matching coil (matching coil) for high-frequency circuits, and is used in electronic devices such as personal computers, DVD players, digital cameras, TVs, mobile phones, car electronics, and medical and industrial machinery. However, the uses of the inductor component 1 are not limited to this, and it can also be used, for example, in tuning circuits, filter circuits, rectifier circuits, and the like.

[0039] The element body 10 is formed in a substantially rectangular parallelepiped shape. The surface of the element body 10 has a first end face 15, a second end face 16 opposite the first end face 15, a bottom face 17 connected between the first end face 15 and the second end face 16, and a top face 18 opposite the bottom face 17. As shown in the figure, the X direction is a direction perpendicular to the first end face 15 and the second end face 16, the Y direction is a direction parallel to the first end face 15, the second end face 16, and the bottom face 17, and the Z direction is a direction perpendicular to the X direction and the Y direction and perpendicular to the bottom face 17. The shape of the inductor component 1 is not particularly limited and may be a cylindrical shape, a polygonal columnar shape, a truncated cone shape, or a truncated polygonal cone shape.

[0040] The element body 10 is a laminated body in which multiple insulating layers 11 are stacked. The stacking direction of the insulating layers 11 is a direction (Y direction) parallel to the first and second end faces 15, 16 and the bottom face 17 of the element body 10. That is, the insulating layers 11 are in a layered form extending in the XZ plane. In this specification, "parallel" is not limited to a strict parallel relationship, but also includes a substantial parallel relationship taking into account a realistic range of variation. Note that in the element body 10, the interfaces between the multiple insulating layers 11 may not be clear due to sintering or the like.

[0041] The insulating layer 11 of the element body 10 is made of an insulating material. The insulating material contains a base material made of an amorphous material containing B, Si, and O, and a crystalline filler. When the element body 10 contains the crystalline filler, the element body 10 can suppress the occurrence of cracks due to impacts during mounting or stresses caused by bending of the substrate. In this case, the strength of the inductor component 1 according to this embodiment can be increased. The amorphous material containing B, Si, and O is, for example, borosilicate glass containing B, Si, and O. In addition to borosilicate glass, the amorphous material may also include glass containing SiO, B, O, K, Li, O, CaO, ZnO, Bi, O, P, and / or Al, O, such as SiO-B, O-K, SiO-B, O-Li, O-Ca, SiO-B, O-P, SiO-B, O-Li, O-Ca, ZnO, or Bi-B, O-B, O-SiO, or a combination of two or more of these glasses.

[0042] The crystalline filler preferably contains, for example, any one of Al, Si, Ti, Zr, Ca, Mg, Fe, and Mn. When the crystalline filler contains any one of the above elements, the strength of the inductor component 1 can be further improved. Furthermore, the crystalline filler is preferably, for example, quartz particles or crystalline silica particles. This can reduce the dielectric constant of the element body 10 and improve the characteristics of the inductor component 1.

[0043] The first external electrode 30 and the second external electrode 40 are made of a conductive material such as Ag or Cu. The first external electrode 30 is, for example, L-shaped and extends from the first end face 15 to the bottom face 17. The second external electrode 40 is, for example, L-shaped and extends from the second end face 16 to the bottom face 17.

[0044] The first external electrode 30 does not protrude from the first end face 15 or the bottom face 17, but may protrude from at least one of the first end face 15 or the bottom face 17. The second external electrode 40 does not protrude from the second end face 16 or the bottom face 17, but may protrude from at least one of the second end face 16 or the bottom face 17.

[0045] The first external electrode 30 may be provided only on the bottom surface 17, without being provided on the first end surface 15, and similarly, the second external electrode 40 may be provided only on the bottom surface 17, without being provided on the second end surface 16. In other words, it is sufficient that the first external electrode 30 and the second external electrode 40 are provided at least on the bottom surface 17.

[0046] The coil 20 is made of, for example, the same conductive material and amorphous material as the first and second external electrodes 30, 40. The coil 20 is spirally wound around the axis AX. A first end of the coil 20 is connected to the first external electrode 30, and a second end of the coil 20 is connected to the second external electrode 40. In this embodiment, the coil 20 and the first and second external electrodes 30, 40 are integrated and no clear boundary exists between them, but this is not limited thereto, and a boundary may exist between them if the coil 20 and the external electrodes are formed using different materials or different manufacturing methods.

[0047] The coil 20 is formed in a substantially oval shape when viewed in the direction of the axis AX, but is not limited to this shape. The shape of the coil 20 may be, for example, a circle, an ellipse, a rectangle, another polygon, or a combination thereof. The axis AX of the coil 20 refers to the central axis of the spiral around which the coil 20 is wound. In the inductor component 1, the direction of the axis AX of the coil 20 and the stacking direction of the insulating layers 11 refer to the same direction. However, the direction of the axis AX of the coil 20 may be perpendicular to the stacking direction of the insulating layers 11.

[0048] The coil 20 has a spirally wound winding portion 21a and an extraction portion 21b that electrically connects the winding portion 21a and the external electrodes 30, 40. The coil 20 includes a coil wiring 21 wound along a plane. The multiple coil wirings 21 are stacked along the axial direction AX. The coil wirings 21 are formed by being wound on a main surface (XZ plane) of the insulating layer 11 that is perpendicular to the axial direction AX. Adjacent coil wirings 21 in the stacking direction are electrically arranged in series via via conductors 26 that penetrate the insulating layer 11 in the thickness direction (Y direction). In this way, the multiple coil wirings 21 are electrically connected in series to each other to form a spiral. Specifically, the coil 20 has a configuration in which multiple coil wirings 21 are electrically connected to each other and stacked, each with less than one turn, and has a helical shape. The coil wiring 21 is composed of one coil conductor layer 25. The coil wiring 21 has a winding portion 21a wound along a plane and an extraction portion 21b that electrically connects the winding portion 21a and the external electrodes 30, 40. The coil wiring 21 (coil conductor layer 25) is formed on the insulating layer 11.

[0049] 3, 4, and 5, the element body 10 includes a high-concentration phosphorus containing portion 101 located along the coil 20. The high-concentration phosphorus containing portion 101 covers at least a portion of each coil wiring 21 along the coil wiring 21. The high-concentration phosphorus containing portion 101 is in contact with the coil wiring 21. Specifically, the high-concentration phosphorus containing portion 101 has a first portion 101a that covers at least a portion of the coil wiring 21 along the coil wiring 21, a second portion 101b that covers at least a portion of the first external electrode 30 along the first external electrode 30, and a third portion 101c that covers at least a portion of the second external electrode 40 along the second external electrode 40.

[0050] The P concentration in the base material in the high-concentration phosphorus containing portion 101 is higher than the P concentration in the base material in the central portion 103 of the element body 10. In this embodiment, the reference center point of the central portion 103 is a point that is halfway between the bottom surface 17 in the X and Y directions and halfway between the first end surface 15 in the Z direction.

[0051] The high concentration phosphorus containing portion 101 covers the entire periphery of the coil 20, but may cover only part of the coil 20. That is, the element body 10 may have the high concentration phosphorus containing portion 101 at a position along a part of the coil 20. More specifically, the high concentration phosphorus containing portion 101 may cover only the inner periphery side of the coil 20. That is, the element body 10 may have the high concentration phosphorus containing portion 101 at a position along the inner periphery of the coil 20. That is, the high concentration phosphorus containing portion 101 may be in contact with the inner edge of the coil 20. Furthermore, the high concentration phosphorus containing portion 101 may cover only the outer periphery side of the coil 20. That is, the element body 10 may have the high concentration phosphorus containing portion 101 at a position along the outer periphery of the coil 20. That is, the high concentration phosphorus containing portion 101 may be in contact with the outer edge of the coil 20.

[0052] According to the above configuration, the element body 10 includes a high-concentration phosphorus containing portion 101 at a position along the coil 20, and the concentration of P in the base material in the high-concentration phosphorus containing portion 101 is higher than the concentration of P in the base material in the central portion 103 of the element body 10. As a result, the high-concentration phosphorus containing portion 101 (glass containing phosphorus) is easily softened, so that adhesion between the coil 20 and the high-concentration phosphorus containing portion 101 along the coil 20 can be ensured during firing, improving the bond between the element body 10 and the coil 20 and suppressing peeling between the element body 10 and the coil 20. Furthermore, because the high-concentration phosphorus containing portion 101 (glass containing phosphorus) has a large linear expansion coefficient, it is possible to reduce the difference in linear expansion coefficient between the coil 20 and the high-concentration phosphorus containing portion 101 along the coil 20, and suppressing the occurrence of cracks in the element body 10 near the coil 20 due to stress caused by the difference in linear expansion coefficient between the element body 10 and the coil 20 inside the product after firing. Therefore, the quality of the inductor component 1 can be improved, and the yield of the inductor components can be increased.

[0053] In short, the inventors of the present application have focused on the fact that glass containing phosphorus tends to have a relatively low softening point (melting point) and a large linear expansion coefficient, and have further found that when phosphorus-containing glass is fired at a high temperature for a long time, the phosphorus element tends to segregate (phase separate) near the coil 20. In other words, the inventors of the present application have found that adjusting the firing temperature and firing time of the phosphorus-containing glass causes the phosphorus element to segregate near the coil 20. For example, when phosphorus-containing borosilicate glass is used as the glass material, it has been confirmed that when the firing temperature is 800°C to 900°C and the firing time is 30 to 60 minutes, P in the glass that is the base material of the element body 10 approaches the metal element of the coil 20, and P can be phase-separated near the coil 20. Based on these findings, the inventors of the present application have arrived at a configuration in which high-concentration phosphorus-containing portion 101, which has a low softening point and a large linear expansion coefficient, is provided along the coil 20.

[0054] Furthermore, since the element body 10 includes the high-concentration phosphorus-containing portion 101 located along the coil 20, the high-concentration phosphorus-containing portion 101 (glass containing phosphorus) has a low softening point, and the surface of the coil 20 can be smoothed by liquid phase sintering. This makes it possible to suppress loss of current flowing through the coil 20. In particular, high-frequency current flows preferentially through the surface of the coil 20 due to the skin effect, so current loss can be further suppressed. This makes it possible to achieve a high Q for the inductor component 1.

[0055] Preferably, the high-concentration phosphorus containing portion 101 is located within 10 μm from the surface of the coil 20. According to the above configuration, the high-concentration phosphorus containing portion 101 can cover the coil 20 in a film-like manner, and the volume of the high-concentration phosphorus containing portion 101 in the element body 10 can be relatively small. This reduces the dielectric constant of the element body 10, reduces dielectric loss, and improves coil characteristics.

[0056] Preferably, the P concentration in the base material in the high-concentration phosphorus containing portion 101 is 1.5 times or more the P concentration in the base material in the central portion 103 of the element body 10. Here, as a method for measuring the P concentration in the base material, for example, the P concentration in the base material can be obtained from the concentration distribution in a cross section of the element body 10 using fluorescence spectroscopy, ICP, WDX, etc. Specifically, the average value of the P concentration in the base material is obtained from a cross-sectional image of the central portion 103 parallel to the XZ plane perpendicular to the stacking direction. Similarly, the average value of the P concentration in the base material is obtained from a cross-sectional image of the high-concentration phosphorus containing portion 101. Thereby, the average value of the P concentration in the base material in the high-concentration phosphorus containing portion 101 and the average value of the P concentration in the base material in the central portion 103 of the element body 10 are compared.

[0057] According to the above configuration, the P concentration in the base material in the high-concentration phosphorus containing portion 101 can be relatively increased, the bondability between the element body 10 and the coil 20 can be further improved, and the difference in linear expansion coefficient between the element body 10 and the coil 20 can be further reduced.

[0058] 4, the coil 20 has first coil wiring 211 and second coil wiring 212 stacked adjacent to each other in the axial direction AX. In FIG. 4, the coil wiring in the second layer from the top is the first coil wiring 211, and the coil wiring in the third layer from the top is the second coil wiring 212, but the other coil wirings may be the first coil wiring 211 and the second coil wiring 212.

[0059] The first coil wiring 211 has an opposing surface 211a that faces the second coil wiring 212. The second coil wiring 212 has an opposing surface 212a that faces the first coil wiring 211. The high-concentration phosphorus containing portion 101 includes a first high-concentration phosphorus containing portion 1011 that covers at least a portion of the opposing surface 211a of the first coil wiring 211, and a second high-concentration phosphorus containing portion 1012 that covers at least a portion of the opposing surface 212a of the second coil wiring 212.

[0060] The element body 10 has an interlayer portion 100 located between a first high-concentration phosphorus containing portion 1011 and a second high-concentration phosphorus containing portion 1012. The concentration of P in the base material in the interlayer portion 100 is lower than the concentration of P in the base material in the first high-concentration phosphorus containing portion 1011, and is also lower than the concentration of P in the base material in the second high-concentration phosphorus containing portion 1012.

[0061] According to the above configuration, it is possible to relatively reduce the concentration of P in the base material in the interlayer portion 100 of the element body 10. This reduces the dielectric constant of the element body 10, reduces dielectric loss, and improves coil characteristics.

[0062] As shown in FIG. 4, the coil 20 has a substantially square cross-sectional shape, but is not limited to this shape. The cross-sectional shape of the coil 20 may be, for example, a circle, an ellipse, a rectangle, another polygon, or a combination thereof. If the cross-sectional shape of the coil 20 is a substantially rectangle with a high aspect ratio, the cross-sectional area of ​​the coil 20 increases, reducing the resistance to high-frequency current, thereby enabling a higher Q factor. The aspect ratio is (thickness t of the coil wiring 21) / (width w of the coil wiring 21). The width w of the coil wiring 21 refers to the width of the coil 20 in a direction perpendicular to the axial AX direction in a cross section perpendicular to the extension direction of the coil wiring 21. The thickness t of the coil wiring 21 refers to the thickness of the coil 20 in the axial AX direction in a cross section perpendicular to the extension direction of the coil wiring 21.

[0063] 5, preferably, coil 20 partially contains an amorphous material (hereinafter referred to as exposed glass 107). The amorphous material contains B, Si, and O, and is made of, for example, the same material as the amorphous material contained in element body 10. Here, "coil 20 partially contains amorphous material" refers to a state in which the amorphous material is not completely embedded in coil 20, and part of the amorphous material is exposed from the outer peripheral surface of coil 20.

[0064] According to the above configuration, it is believed that in the sintering step of the manufacturing method of the inductor component 1, liquid layer sintering has progressed to the extent that the amorphous material reaches the surface from the inside of the coil 20. This further improves the smoothness of the coil 20, making it possible to further increase the Q factor at high frequencies.

[0065] Furthermore, due to the skin effect, high-frequency current flows preferentially on the surface of the coil 20. Therefore, when the coil 20 partially encloses the exposed glass 107, recesses are formed on the surface of the coil 20, increasing the surface area of ​​the coil 20. This reduces the electrical resistance. Therefore, it becomes possible to further increase the Q factor at high frequencies.

[0066] 5, coil 20 preferably completely encapsulates amorphous material (hereinafter referred to as encapsulated glass 105). Here, "coil 20 completely encapsulates amorphous material" refers to a state in which the amorphous material is completely embedded in coil 20 and is not exposed from the outer circumferential surface of coil 20.

[0067] According to the above configuration, when coil 20 completely encapsulates encapsulated glass 105, an interface between coil 20 and encapsulated glass 105 is formed within coil 20. This increases the surface area of ​​coil 20, and the electrical resistance is reduced due to the skin effect at high frequencies. This further enables a higher Q at high frequencies.

[0068] As shown in FIG. 5, the content of the crystalline filler in the high-concentration phosphorus containing portion 101 is preferably 80% or more and 120% or less of the content of the crystalline filler in the central portion 103 of the element body 10.

[0069] Here, the content of the crystalline filler is calculated, for example, from the area of ​​the crystalline filler per unit area in the cross section of the element body 10. Specifically, the area ratio of the crystalline filler per unit area is obtained from a cross-sectional image (SEM image) of the central portion 103 parallel to the XZ plane perpendicular to the stacking direction. This ratio corresponds to the content of the crystalline filler in the central portion 103 of the element body 10. Similarly, the area ratio of the crystalline filler per unit area is obtained from a cross-sectional image of the high-concentration phosphorus containing portion 101. This ratio corresponds to the content of the crystalline filler in the high-concentration phosphorus containing portion 101.

[0070] According to the above configuration, the content of the crystalline filler does not decrease in the high-concentration phosphorus containing portion 101. In this way, the amount of the crystalline filler can be secured in the high-concentration phosphorus containing portion 101, and the strength of the element body 10 can be secured.

[0071] On the other hand, if the content of crystalline filler in the high-concentration phosphorus containing portion 101 becomes high, softening of the high-concentration phosphorus containing portion 101 may be suppressed, which may reduce the bondability between the element body 10 and the coil 20. Furthermore, the difference in linear expansion coefficient between the high-concentration phosphorus containing portion 101 (element body 10) and the coil 20 may increase, which may cause cracks to occur in the element body 10 near the coil due to stress caused by the difference in linear expansion coefficient. However, since the concentration of P in the base material of the high-concentration phosphorus containing portion 101 is high, it is possible to promote softening of the high-concentration phosphorus containing portion 101 and improve the bondability between the element body 10 and the coil 20, while reducing the difference in linear expansion coefficient between the high-concentration phosphorus containing portion 101 (element body 10) and the coil 20 and suppress cracks in the element body 10 near the coil.

[0072] Therefore, the strength of element body 10 can be ensured, and inductor component 1 can be produced with a high yield.

[0073] As shown in FIG. 4 , the multiple coil wirings 21 preferably include one coil wiring 21 and another coil wiring 21, and in a cross section including the axis AX, the concentration distribution of P in the base material in a high-concentration phosphorus-containing portion 101 that covers at least a portion of the periphery of the one coil wiring 21 is different from the concentration distribution of P in the base material in a high-concentration phosphorus-containing portion 101 that covers at least a portion of the periphery of the other coil wiring 21. For example, in the high-concentration phosphorus-containing portion 101 that covers the one coil wiring 21, the concentration of P in the base material is highest on the outer periphery side of the one coil wiring 21, and in the high-concentration phosphorus-containing portion 101 that covers the other coil wiring 21, the concentration of P in the base material is highest on the inner periphery side of the other coil wiring 21. Note that the positions where the high-concentration phosphorus-containing portions are thickest may differ, rather than the positions of the high-concentration portions. In FIG. 4 , any one coil wiring 21 among the five layers of coil wiring 21 is referred to as the one coil wiring 21, and the other coil wirings 21 among the five layers of coil wiring 21 are referred to as the other coil wirings 21.

[0074] According to the above configuration, in the cross section including the axis AX, the concentration distribution of P in the base material of the high-concentration phosphorus containing portion 101 becomes random and irregular due to the different coil wirings 21. This makes it possible to improve the bonding between the element body 10 and the coil 20 uniformly throughout the inductor component 1, and to reduce the difference in the linear expansion coefficient between the element body 10 and the coil 20.

[0075] (Manufacturing method for inductor components) An example of a method for manufacturing an inductor component will now be described with reference to Fig. 2. The method for manufacturing an inductor component includes a mother laminate forming step of forming a mother laminate, a cutting step of cutting the mother laminate to form laminates, a sintering step of sintering the laminates, and a polishing step of polishing the sintered laminates.

[0076] [Mother laminate formation process] The mother laminate is an assembly of a plurality of laminates formed together. Hereinafter, the members in the assembly state will be described using the same names and symbols as the members after separation.

[0077] In the mother laminate formation step, an insulating layer 11 is formed, and a conductor layer is formed on the insulating layer 11. This step is repeated to stack a plurality of insulating layers 11 each having a conductor layer. In this way, a mother laminate is formed. The mother laminate formation step using the screen printing method will be described below.

[0078] (1. Preparation of paste) An insulating paste, a conductive paste, and a conductive paste for external electrodes are prepared. The insulating paste contains a filler material (an example of a crystalline filler), a glass material (an example of a base material; more specifically, glass powder) made of an amorphous material, and a solvent. The amorphous material is, for example, borosilicate glass. The glass material contains phosphorus. The crystalline filler is, for example, ceramics. The insulating paste may further contain an organic material or a composite material, and among these, materials with low dielectric constants and dielectric losses are preferred. The organic material is, for example, a polymer (more specifically, epoxy resin, acrylic resin, fluororesin, etc.). The composite material is, for example, a glass epoxy resin.

[0079] The conductive paste contains a glass material made of an amorphous material, a conductive material (more specifically, metal powder), and a solvent. The conductive material is preferably a highly conductive material, such as Ag, Cu, or Au. The conductive paste for external electrodes contains a conductive material and a solvent, but does not contain a glass material made of an amorphous material.

[0080] (2. Formation of outer insulating layer) In FIG. 2, the outer insulating layer (insulating paste layer) 11 corresponds to the first insulating layer 11 from the bottom. Using a screen printing method, the insulating paste is applied onto a substrate such as a carrier film (not shown). This process is repeated to form the outer insulating layer 11 having a predetermined thickness.

[0081] (3. Formation of insulating layer (first layer) with conductive layer) An insulating paste is applied onto the outer insulating layer 11 by screen printing to form the insulating layer 11. The insulating layer 11 corresponds to the second insulating layer 11 from the bottom in FIG.

[0082] Next, a conductive paste is pattern-printed into a predetermined shape on the insulating layer 11 using a screen printing method to form a conductor layer. Besides screen printing, a photolithography method using a photosensitive conductive paste may also be used to form the conductor layer. Specifically, the photosensitive conductive paste layer is exposed to active energy rays (more specifically, ultraviolet rays, etc.) through a photomask that follows the desired coil pattern. After exposure, the layer is developed with a developer (more specifically, an alkaline solution, etc.). This forms a coil conductor layer 25 having the desired coil pattern. Similarly, an external conductive layer having the desired pattern is formed using a conductive paste for the external electrodes. As a result, an insulating layer 11 is formed that includes the coil conductor layer 25 and the external conductor layer.

[0083] (4. Formation of insulating layer (second layer) with conductive layer) A second insulating layer 11 having a conductor layer is formed. This insulating layer 11 corresponds to the third insulating layer 11 from the bottom in Fig. 2. The second insulating layer 11 differs from the first insulating layer 11 in that it has openings and via holes, but does not have a coil conductor layer 25.

[0084] An insulating paste is applied onto the first insulating layer 11 to form an insulating paste layer. Laser light is irradiated onto predetermined locations on the insulating paste layer to form the insulating layer 11 with openings and via holes. A conductive layer is formed in the openings and via holes using a screen printing method. This forms the insulating layer 11 with a conductor layer and via conductors 26.

[0085] (5. Formation of insulating layer (third layer) with conductive layer) A third insulating layer 11 having a conductor layer is formed. This insulating layer 11 corresponds to the fourth insulating layer 11 from the bottom in Fig. 2. The third insulating layer 11 differs from the second insulating layer 11 in that it has a coil conductor layer 25.

[0086] By irradiating predetermined locations on the insulating paste layer with laser light, an insulating layer with openings and via holes is formed on the second insulating layer 11. The conductive paste is pattern-printed into the desired shape to form a conductor layer. As a result, a coil conductor layer 25 is formed in the via holes and on the insulating layer 11, and an external conductor layer is formed in the openings. A third insulating layer 11 is formed.

[0087] (6. Lamination) The process of forming the second and third insulating layers 11 is repeated to form the fourth and subsequent insulating layers 11. The fourth and subsequent insulating layers 11 correspond to the fifth to tenth insulating layers 11 from the bottom in FIG. 2. Then, an outer insulating layer 11 is formed. The outer insulating layer 11 corresponds to the eleventh insulating layer 11 from the bottom in FIG. 2. In this manner, a mother laminate is produced.

[0088] A mark layer may be formed before or after forming the outer insulating layer 11. The mark layer is, for example, a colored insulating paste mixed with a filler.

[0089] Moreover, instead of the screen printing method, a spin coating method or a spray coating method may be used.

[0090] The mother laminate may also have, as the bottom layer, an insulating layer 11 that does not have a conductor layer.

[0091] Alternatively, the openings and via holes may be formed by pressing or spin coating an insulating material sheet, or by spray coating followed by laser or drilling, or by photolithography using a photosensitive insulating paste.

[0092] The conductor layer may be formed by forming and stacking multiple conductor layers to form a conductor layer having a cross-sectional shape (rectangle) with a high aspect ratio. The formation of multiple conductor layers may be performed by repeating the above-mentioned screen printing method and photolithography method multiple times, or by combining other methods.

[0093] Instead of using a conductive paste layer, the conductor layer may be formed using a sputtering method, a vapor deposition method, a foil compression bonding method, or the like. Furthermore, the patterning of the conductor layer is not limited to the above-mentioned screen printing method, and a subtractive method (more specifically, a photolithography method, etc.) or an additive method (more specifically, a semi-additive method, etc.) may also be used. The semi-additive method is, for example, a method in which a negative pattern is formed, a plating film is formed, and unnecessary portions are removed.

[0094] In the mother laminate formation step, the mother laminate may be manufactured by forming the second, fourth, sixth, eighth, and tenth insulating layers 11 from the bottom and the outer insulating layers 11 shown in Fig. 2. The inductor component 1 manufactured by this method has a structure in which insulating layers having coil conductor layers are directly stacked.

[0095] [Cutting process] In the cutting step, the mother laminate is cut to form laminates, for example, by dicing or the like so that the outer conductor layers are exposed from the cut surfaces to form a plurality of unsintered laminates.

[0096] [Sintering process] In the sintering step, the laminate is sintered. At this time, since the material of the insulating layer 11 (insulating paste) contains phosphorus, by firing the laminate at a high temperature above a certain temperature (800°C or higher), elemental phosphorus segregates near the coil wiring 21, and high-concentration phosphorus-containing portions 101 can be formed along the coil wiring 21. The segregation of the high-concentration phosphorus-containing portions 101 is controlled by the temperature and time during firing. Note that, as long as elemental phosphorus segregates near the coil wiring 21, the firing temperature may be 800°C or lower. Note that, as another method for segregating elemental phosphorus, glass containing phosphorus may be used as the material for the coil wiring 21 (conductive paste). In this way, by firing the laminate, glass containing phosphorus seeps out around the coil wiring 21 as a sintered body of the conductive paste, and phosphorus can be segregated near the coil wiring 21.

[0097] In this way, the high-concentration phosphorus containing portion 101 can be formed at a position along the coil 20. The high-concentration phosphorus containing portion 101 does not need to completely cover the coil 20, but only needs to be located along the coil 20. In other words, as long as the high-concentration phosphorus containing portion 101 is in contact with the coil 20, it may be located partially, for example, only on the inner circumferential side or only on the outer circumferential side of the coil 20. The high-concentration phosphorus containing portion 101 may be located along the outer and inner edges of the coil 20.

[0098] 6A to 6C, the formation of the coil conductor layer 25 in the sintering process will be described. 6A to 6C are cross-sectional views showing the change in the coil conductor layer 25 in the sintering process. As shown in Fig. 6A, the coil conductor layer 25 before sintering is a conductor paste in which metal powder 111 and glass powder 113 are dispersed in varnish 19.

[0099] When sintering is started in this state, as shown in Figure 6B, the solvent burns off and dissipates, causing adjacent metal powder particles 111 to locally shrink (neck) and sinter, becoming metal parts 115. At this time, the glass powder particles 113 soften and flow between the metal parts 115, becoming glass parts 117.

[0100] At this time, as shown in FIG. 6C , the softened glass portion 117 is extruded outward due to the contraction of the metal powder 111 and moves toward the outer periphery of the coil conductor layer 25. As a result, the surface of the coil conductor layer 25 is sintered in the extruded softened glass (glass portion 117), i.e., in the liquid phase, further promoting sintering and facilitating surface smoothing and crystal growth. This reduces the number of crystal grain boundaries that obstruct current flow and reduces electrical resistance that leads to loss. As a result, the inductor component 1 can achieve a higher Q. At this time, the glass portion 117 is formed as an encapsulated glass 105 and an exposed glass 107. The encapsulated glass 105 is formed when the glass portion 117, which was located farther from the outer periphery of the coil conductor layer 25, remains within the coil conductor layer 25 without being extruded. The exposed glass 107 is formed when the glass portion 117, which was located relatively close to the outer periphery of the coil conductor layer 25, is not completely extruded and remains near the surface of the coil conductor layer 25. Therefore, the formed coil conductor layer 25 includes a metal portion 115 and a glass portion 117, and the glass portion 117 includes the encapsulated glass 105 and the exposed glass 107, as shown in FIG. 6, which will be described later.

[0101] The proportion of encapsulated glass 105 in glass portion 117 depends on the amount of exposed glass 107 extruded, and can therefore be controlled using as an index the degree of sintering, more specifically, the degree of contraction based on the volume of metal powder 111. The degree of contraction of metal powder 111 is controlled by, for example, the temperature and time during firing.

[0102] [Polishing process] In the polishing step, the sintered laminate is polished by, for example, barrel processing.

[0103] [Other processes] The manufacturing method of the inductor component 1 may further include a plating step. The plating step is performed after the polishing step, and plating is performed on the external conductor layer exposed on the outer surface of the laminate. Alternatively, after the polishing step and before the plating step, an additional conductor layer may be provided on the external conductor layer of the laminate by a dipping method using a conductive paste, a sputtering method, or the like.

[0104] Second Embodiment FIG. 7 is a plan view showing a second embodiment of the inductor component 1A, corresponding to FIG. 3. The second embodiment differs from the first embodiment in the configuration of the high-concentration phosphorus-containing portion. This different configuration will be described below. Note that in the second embodiment, the same reference numerals as those in the first embodiment represent the same configuration as in the first embodiment, and therefore their description will be omitted.

[0105] 7, in the inductor component 1A of the second embodiment, the high-concentration phosphorus containing portion 101A has only a first portion 101a that runs along the coil wiring 21 and covers at least a portion of the coil wiring 21. In other words, the high-concentration phosphorus containing portion 101A does not have the second portion 101b and the third portion 101c of the first embodiment. According to the above configuration, the high-concentration phosphorus containing portion 101A covers only the coil wiring 21, so that the volume of the high-concentration phosphorus containing portion 101A in the element body 10 can be made relatively small. Therefore, the dielectric constant of the element body 10 can be reduced, the dielectric loss can be reduced, and the coil characteristics can be improved.

[0106] The present disclosure is not limited to the above-described embodiments, and design modifications are possible within the scope of the present disclosure. For example, the features of the first and second embodiments may be combined in various ways.

[0107] In the above embodiment, the high-concentration phosphorus-containing portion is provided along all of the coil wirings, but it is sufficient that the high-concentration phosphorus-containing portion is provided along at least one of the coil wirings.

[0108] In the above embodiment, the coil partially contains the exposed glass, but the coil does not necessarily have to contain the exposed glass.

[0109] In the above embodiment, the coil completely contains the encapsulated glass, but the coil does not necessarily have to contain the encapsulated glass.

[0110] The present disclosure includes the following aspects. <1> an element body made of an insulating material; a coil disposed within the element body and wound helically along the axis; Equipped with the insulating material contains a base material made of an amorphous material containing B, Si, and O, and a crystalline filler; the element body includes a high-concentration phosphorus-containing portion located along the coil, The inductor component, wherein the concentration of P in the base material in the high-concentration phosphorus-containing portion is higher than the concentration of P in the base material in the central portion of the element body. <2> The high-concentration phosphorus-containing portion is located within 10 μm from the surface of the coil. <1> The inductor component according to claim 1. <3> the concentration of P in the base material in the high-concentration phosphorus containing portion is 1.5 times or more the concentration of P in the base material in the central portion of the element body; <1> or <2> The inductor component according to claim 1. <4> the coil has first and second coil wirings stacked adjacent to each other in the axial direction, the high-concentration phosphorus-containing portion includes a first high-concentration phosphorus-containing portion covering at least a part of a surface of the first coil wiring facing the second coil wiring, and a second high-concentration phosphorus-containing portion covering at least a part of a surface of the second coil wiring facing the first coil wiring, the element body has an interlayer portion located between the first high concentration phosphorus containing portion and the second high concentration phosphorus containing portion, and a concentration of P in the base material in the interlayer portion is lower than a concentration of P in the base material in the first high concentration phosphorus containing portion and is also lower than a concentration of P in the base material in the second high concentration phosphorus containing portion; <1> from <3> 10. An inductor component according to any one of the preceding claims. <5> The coil partially contains an amorphous material containing B, Si, and O. <1> from <4> 10. An inductor component according to any one of the preceding claims. <6> The coil completely encapsulates an amorphous material containing B, Si, and O. <1> from <5> 10. An inductor component according to any one of the preceding claims. <7> The crystalline filler contains any one of Al, Si, Ti, Zr, Ca, Mg, Fe, and Mn. <1> from <6> 10. An inductor component according to any one of the preceding claims. <8> The crystalline filler is quartz particles or crystalline silica particles. <1> from <7> 10. An inductor component according to any one of the preceding claims. <9> the content of the crystalline filler in the high-concentration phosphorus-containing portion is 80% or more and 120% or less of the content of the crystalline filler in the central portion of the element body; <1> from <8> 10. An inductor component according to any one of the preceding claims. <10> The coil has a plurality of coil wires stacked along the axis, In a cross section including the axis, a concentration distribution of P in the base material in the high-concentration phosphorus containing portion that covers at least a part of the periphery of one coil wiring is different from a concentration distribution of P in the base material in the high-concentration phosphorus containing portion that covers at least a part of the periphery of another coil wiring. <1> from <9> 10. An inductor component according to any one of the preceding claims. [Explanation of symbols]

[0111] 1.1A inductor components 10 Base 11 Insulating layer 20 coils 21 Coil wiring 21a Winding part 21b Drawer section 25 Coil conductor layer 26 Via conductor 30 1st external electrode 40 2nd external electrode 100 Interlayer part 101,101A High concentration phosphorus containing area 101a Part 1 101b Part 2 101c Part 3 103 Central part 105 Inclusion Glass 107 Exposed Glass 111 Metal powder 113 Glass Powder 115 Metal Part 117 Glass Section 211 First coil wiring 211a Opposite side 212 Second coil wiring 212a Opposite side 1011 1st high concentration phosphorus containing part 1012 2nd high concentration phosphorus containing part AX axis

Claims

1. an element body made of an insulating material; a coil disposed within the element body and wound helically along the axis; Equipped with The insulating material contains a base material made of an amorphous material containing B, Si, and O, and a crystalline filler, the base material containing phosphorus (P), the element body includes a central portion and a high-concentration phosphorus-containing portion located along the coil, the central portion of the element body is a portion within a radius of 10 μm or a radius of 20 μm from the center point of the element body in a cross section of the element body including the center point, the concentration of P in the base material in the high-concentration phosphorus containing portion is higher than the concentration of P in the base material in the central portion of the element body; The high-concentration phosphorus-containing portion contains the crystalline filler at a content rate of 80% to 120% of the content rate of the crystalline filler in the central portion of the element body.

2. 2. The inductor component according to claim 1, wherein the high-concentration phosphorus-containing portion is located within 10 μm from the surface of the coil.

3. 3. The inductor component according to claim 1, wherein the concentration of P in the base material in the high-concentration phosphorus-containing portion is 1.5 times or more the concentration of P in the base material in the central portion of the element body.

4. the coil has first and second coil wirings stacked adjacent to each other in the axial direction, the high-concentration phosphorus containing portion includes a first high-concentration phosphorus containing portion covering at least a part of a surface of the first coil wiring facing the second coil wiring, and a second high-concentration phosphorus containing portion covering at least a part of a surface of the second coil wiring facing the first coil wiring, 3. The inductor component according to claim 1, wherein the element body has an interlayer portion located between the first high-concentration phosphorus containing portion and the second high-concentration phosphorus containing portion, and a concentration of P in the base material in the interlayer portion is lower than a concentration of P in the base material in the first high-concentration phosphorus containing portion and is lower than a concentration of P in the base material in the second high-concentration phosphorus containing portion.

5. 3. The inductor component according to claim 1, wherein the coil partially contains an amorphous material containing B, Si, and O.

6. 3. The inductor component according to claim 1, wherein the coil completely encapsulates an amorphous material containing B, Si, and O.

7. 3. The inductor component according to claim 1, wherein the crystalline filler contains any one of Al, Si, Ti, Zr, Ca, Mg, Fe, and Mn.

8. 3. The inductor component according to claim 1, wherein the crystalline filler is quartz particles or crystalline silica particles.

9. The coil has a plurality of coil wires stacked along the axis, 3. The inductor component according to claim 1, wherein, in a cross section including the axis, a concentration distribution of P in the base material in the high-concentration phosphorus containing portion that covers at least a portion of a periphery of one coil wiring is different from a concentration distribution of P in the base material in the high-concentration phosphorus containing portion that covers at least a portion of a periphery of another coil wiring.

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