Substrate built into electronic component and method for manufacturing substrate built into electronic component

Abstract

A substrate 101 built into an electronic component comprises: a core substrate 110 which has a first surface 111 and a second surface 112 opposite the first surface 111, and is provided with an opening 120 on the inside; a multilayer ceramic electronic component 1 provided in the opening 120 and having a first external electrode 51, in a first direction orthogonal to the second surface 112 of the core substrate 110 and headed toward the first surface 111, and having a second external electrode 52 in a second direction opposite the first direction; a sealing material 130 provided, between the opening 120 and the multilayer ceramic electronic component 1, on the first external electrode 51 and the first surface 111, and having a third surface 133 on the first surface 111 side; and a first via conductor 141 penetrating the third surface 133 of the sealing material 130 and electrically connected to the first external electrode 51 of the multilayer ceramic electronic component 1. The multilayer ceramic electronic component 1 includes: a substantially rectangular parallelepiped-shaped laminate 10 having a first end face 13 and a second end face 14 facing the first end face 13; the first external electrode 51 provided on the first end face 13; and the second external electrode 52 provided on the second end face 14. The laminate 10 includes: an effective part 30, in which a plurality of internal electrode layers 21, 22 are overlapped and which functions as an electronic component; and a lead-out part 31 for drawing the internal electrode layer 21 out from the effective part 30 to the first external electrode 51. In the first direction, the thickness A1 of the lead-out part 31 on the first end face 13 side is greater than the thickness B1 of the first external electrode 51.

Description

Substrate with built-in electronic components and method for manufacturing the same

[0001] The present invention relates to a substrate with built-in electronic components and a method for manufacturing such a substrate.

[0002] Patent document 1 describes a substrate with built-in electronic components, in which components are inserted into vias in a substrate core and sealed, and then openings are formed on the front and back surfaces of the substrate core using a technique such as a laser to expose the conductive surfaces of the components, and a conductive layer is formed on the exposed areas.

[0003] Patent Document 2 describes a multilayer ceramic capacitor as an electronic component. The multilayer ceramic capacitor has first and second external electrodes formed on opposing end faces of a laminate. First internal electrode layers and second internal electrode layers are alternately stacked inside the laminate, and the first internal electrode layers and second internal electrode layers are respectively extended to the opposing end faces of the laminate.

[0004] U.S. Patent Application Publication No. 2005 / 0016763 Patent No. 6,596,547

[0005] When an electronic component having the structure described in Patent Document 2 is used as an electronic component for an electronic component-embedded substrate having the structure described in Patent Document 1, the electronic component is placed in a cavity (via in Patent Document 1) and sealed with a sealing material. Next, holes are drilled in the sealing material with a laser to expose the external electrodes of the electronic component. Vias are formed by plating so as to connect to the exposed external electrodes.

[0006] The inventors recognized that when manufacturing a substrate with built-in electronic components using the above process, heat generated during laser drilling can damage the internal electrode layers (effective portions) that generate the capacitance of the multilayer ceramic capacitor, and that plating liquid can penetrate into the effective portions during plating, causing damage to the effective portions.

[0007] The present invention has been made to solve the above problems, and has an object to provide a substrate with built-in electronic components in which damage to the active parts of the electronic components is reduced.

[0008] The electronic component built-in substrate of the present invention includes a core substrate having a first surface and a second surface opposite to the first surface and having an opening provided therein; a multilayer ceramic electronic component provided in the opening, the multilayer ceramic electronic component having a first external electrode in a first direction perpendicular to the second surface of the core substrate and extending toward the first surface, and a second external electrode in a second direction opposite to the first direction; a sealing material provided between the opening and the multilayer ceramic electronic component, on the first external electrode and on the first surface, the sealing material having a third surface on the first surface side; and a first via conductor penetrating the third surface of the sealing material and electrically connected to the first external electrode of the multilayer ceramic electronic component. the laminate has an effective portion where a plurality of internal electrode layers are overlapped and function as an electronic component, and an extraction portion that extracts the internal electrode layers from the effective portion to the first external electrode, and the electronic component-embedded substrate has a thickness A1 of the extraction portion on the first end face side in a direction along the first direction that is greater than a thickness B1 of the first external electrode.

[0009] A method for manufacturing a substrate with built-in electronic components of the present invention includes the steps of: preparing a core substrate having a first surface and a second surface opposite to the first surface, the core substrate having an opening therein; arranging a multilayer ceramic electronic component to be used in the substrate with built-in electronic components of the present invention, the multilayer ceramic electronic component having a first external electrode in a first direction perpendicular to the second surface of the core substrate and toward the first surface, and a second external electrode in a second direction opposite to the first direction; providing a sealing material between the opening and the multilayer ceramic electronic component, on the first external electrode, and on the first surface, for sealing; providing a via hole penetrating a third surface of the sealing material, which is the surface of the sealing material provided on the first surface side, by laser processing; and providing a first via conductor electrically connected to the first external electrode of the multilayer ceramic electronic component by plating in the via hole.

[0010] According to the present invention, it is possible to provide a substrate with built-in electronic components in which damage to the active parts of the electronic components is reduced.

[0011] FIG. 1 is a perspective view schematically illustrating an example of a multilayer ceramic capacitor as a multilayer ceramic electronic component. FIG. 2 is a cross-sectional view (LT cross-sectional view) taken along line A-A of the multilayer ceramic capacitor shown in FIG. 1. FIG. 3 is a cross-sectional view schematically illustrating an example of an electronic component-embedded substrate incorporating a multilayer ceramic capacitor. FIG. 4 is an explanatory diagram of thicknesses B1, C1, B2, and C2. FIG. 5 is an explanatory diagram of thicknesses A1, D1, A2, and D2. FIG. 6 is an explanatory diagram of thicknesses A1, A2, and heights E1 and E2. FIG. 7 is an LT cross-sectional view schematically illustrating an example of an electronic component-embedded substrate provided with a multilayer ceramic coil as a multilayer ceramic electronic component. FIG. 8 is an LT cross-sectional view schematically illustrating another example of an electronic component-embedded substrate provided with a multilayer ceramic coil as a multilayer ceramic electronic component. FIG. 9 is a process diagram schematically illustrating a manufacturing process for an electronic component-embedded substrate. FIG. 10 is a process diagram schematically illustrating a manufacturing process for an electronic component-embedded substrate. FIG. 11 is a process diagram schematically illustrating a manufacturing process for an electronic component-embedded substrate. 12 and 13 are process diagrams that schematically show the manufacturing process of an electronic component built-in substrate.

[0012] The following describes a substrate with built-in electronic components and a method for manufacturing a substrate with built-in electronic components according to the present invention. However, the present invention is not limited to the following configurations, and can be modified as appropriate within the scope of the present invention. Note that a combination of two or more of the individual desirable configurations described below also falls within the scope of the present invention.

[0013] The electronic component-embedded substrate of the present invention includes a multilayer ceramic electronic component disposed in an opening of a core substrate. First, an example of a multilayer ceramic electronic component included in the electronic component-embedded substrate will be described. The multilayer ceramic electronic component includes a substantially rectangular parallelepiped laminate having a first end face and a second end face opposite the first end face, a first external electrode disposed on the first end face, and a second external electrode disposed on the second end face. The laminate includes an effective portion in which multiple internal electrode layers are stacked and function as an electronic component, and an extension portion that extends the internal electrode layers from the effective portion to the first external electrode. The laminate described below also includes an extension portion that extends the internal electrode layers from the effective portion to the second external electrode.

[0014] Fig. 1 is a perspective view schematically showing an example of a multilayer ceramic capacitor as a multilayer ceramic electronic component, and Fig. 2 is a cross-sectional view of the multilayer ceramic capacitor taken along line AA (LT cross-sectional view) shown in Fig. 1.

[0015] The lamination direction, width direction, and length direction of the multilayer ceramic capacitor and laminate are defined by arrows T, W, and L, respectively, in the multilayer ceramic capacitor 1 and laminate 10 shown in Fig. 1. Here, the lamination direction T, width direction W, and length direction L are perpendicular to each other. The lamination direction T is the direction in which the plurality of dielectric ceramic layers 20 and the plurality of internal electrode layers (first internal electrode layers 21 and second internal electrode layers 22) are stacked up.

[0016] The multilayer ceramic capacitor 1 shown in FIG. 1 includes a laminate 10 and a first external electrode 51 and a second external electrode 52 provided on both end surfaces of the laminate 10, respectively.

[0017] 1, the laminate 10 has a rectangular parallelepiped or approximately rectangular parallelepiped shape, and has a first main surface 11 and a second main surface 12 that face each other in a stacking direction T, a first side surface 13 and a second side surface 14 that face each other in a width direction W that is perpendicular to the stacking direction T, and a first end surface 15 and a second end surface 16 that face each other in a length direction L that is perpendicular to the stacking direction T and the width direction W. Note that the rectangular parallelepiped-shaped laminate also includes a cubic-shaped laminate.

[0018] A cross section of the multilayer ceramic capacitor 1 or the laminate 10 that is orthogonal to the first end face 15 and the second end face 16 and parallel to the stacking direction T is referred to as an LT cross section, which is a cross section along the length direction L and the stacking direction T. A cross section of the multilayer ceramic capacitor 1 or the laminate 10 that is orthogonal to the first side face 13 and the second side face 14 and parallel to the stacking direction T is referred to as a WT cross section, which is a cross section along the width direction W and the stacking direction T. A cross section of the multilayer ceramic capacitor 1 or the laminate 10 that is orthogonal to the first side face 13, the second side face 14, the first end face 15, and the second end face 16 and perpendicular to the stacking direction T is referred to as an LW cross section, which is a cross section along the length direction L and the width direction W.

[0019] It is preferable that the corners and ridges of the laminate 10 are rounded. A corner is a portion where three surfaces of the laminate intersect, and a ridge is a portion where two surfaces of the laminate intersect.

[0020] 2 , the laminate 10 has a laminated structure including a plurality of dielectric ceramic layers 20 laminated in a lamination direction T, and a plurality of pairs of first internal electrode layers 21 and second internal electrode layers 22 formed along the interfaces between the dielectric ceramic layers 20. The dielectric ceramic layers 20 extend along the width direction W and the length direction L, and each of the first internal electrode layers 21 and second internal electrode layers 22 extends in a flat plate shape along the dielectric ceramic layers 20.

[0021] The first internal electrode layer 21 is extended to a first end face 15 of the laminate 10 , while the second internal electrode layer 22 is extended to a second end face 16 of the laminate 10 .

[0022] The first internal electrode layer 21 and the second internal electrode layer 22 face each other in the stacking direction T via the dielectric ceramic layer 20. A capacitance is generated in the portion where the first internal electrode layer 21 and the second internal electrode layer 22 face each other via the dielectric ceramic layer 20. The portion where the capacitance is generated is an effective portion (shown as an effective portion 30 in FIG. 2 ) that functions as an electronic component.

[0023] The lead-out portion is a portion where the internal electrode layer is led out from the effective portion 30 to the first external electrode or the second external electrode. In Fig. 2, the first lead-out portion 31 is a portion where the first internal electrode layer 21 is led out from the effective portion 30 to the first external electrode 51, and the second lead-out portion 32 is a portion where the second internal electrode layer 22 is led out from the effective portion 30 to the second external electrode 52.

[0024] When the multilayer ceramic electronic component is a multilayer ceramic capacitor, the effective portion is also called a capacitive portion that exhibits capacitance, and the extended portion is also called a non-capacitive portion because it does not exhibit capacitance.

[0025] The internal electrode layers (first internal electrode layer 21 and second internal electrode layer 22) each preferably contain a metal as a conductive material, and preferably contain Ni. In addition to the metal, the internal electrode layers may contain the same dielectric ceramic material as the dielectric ceramic layer 20.

[0026] The thickness of each of the internal electrode layers (first internal electrode layer 21 and second internal electrode layer 22) is preferably 1.5 μm or less, and the thickness of each of the internal electrode layers is preferably 0.4 μm or more.

[0027] The dielectric ceramic layer is made of a ceramic material, for example, BaTiO ３ It is preferable that the internal electrode layer is made of a dielectric ceramic material containing, as a main component, Ni, etc. Furthermore, elements such as Ni contained in the internal electrode layer may be diffused into the dielectric ceramic layer.

[0028] The thickness of the dielectric ceramic layers is preferably 10 μm or less. Also, the thickness of each dielectric ceramic layer is preferably 0.5 μm or more. The thickness of the dielectric ceramic layers here refers to the thickness of the dielectric ceramic layers between the internal electrode layers, i.e., the thickness of the dielectric ceramic layers in the effective section (capacitive section).

[0029] The first external electrode 51 is provided on the first end surface 15 of the laminate 10, and in Fig. 1 has a portion that extends around to each of the first main surface 11, the second main surface 12, the first side surface 13, and the second side surface 14. The first external electrode 51 is connected to the first internal electrode layer 21 at the first end surface 15.

[0030] The second external electrode 52 is provided on the second end surface 16 of the laminate 10, and in Fig. 1 has a portion that extends around to each of the first main surface 11, the second main surface 12, the first side surface 13, and the second side surface 14. The second external electrode 52 is connected to the second internal electrode layer 22 at the second end surface 16.

[0031] The first and second external electrodes are preferably external electrodes formed by applying and drying a metal paste, and are preferably not external electrodes formed by plating. If the external electrodes are formed by plating, the external electrodes contain little or no components other than metals. On the other hand, if the external electrodes are formed by applying and drying a metal paste, components other than metals contained in the metal paste remain in the external electrodes. Preferably, the components other than metals include glass.

[0032] The metal paste is preferably a Cu paste, and therefore the first and second external electrodes are preferably made of only a metal paste, and preferably contain Cu and glass.

[0033] Next, an electronic component-embedded substrate including the multilayer ceramic capacitor described above will be described. The electronic component-embedded substrate described below has a top-bottom symmetrical structure, with a first end face of the laminate constituting the multilayer ceramic electronic component, a first external electrode of the multilayer ceramic electronic component, a third surface of the sealing material, and a first via conductor located on a first surface side of the core substrate. A second end face of the laminate constituting the multilayer ceramic electronic component, a second external electrode of the multilayer ceramic electronic component, a fourth surface of the sealing material, and a second via conductor located on a second surface side of the core substrate.

[0034] In the electronic component-embedded substrate of the present invention, only the components on the first surface side of the core substrate are specified. However, with regard to which of the two main surfaces of the core substrate is to be the first main surface, if the configuration on one main surface side satisfies the requirements for defining the electronic component-embedded substrate of the present invention, while the configuration on the other main surface side does not, the main surface on the side that satisfies the requirements is to be the first main surface.

[0035] Generally, an electronic component built-in substrate has a symmetrical structure on the first main surface side and the second main surface side of a core substrate, as in the electronic component built-in substrate described below, and therefore often simultaneously satisfies or does not simultaneously satisfy the requirements defined as an electronic component built-in substrate of the present invention on both the first main surface side and the second main surface side of the core substrate. Below, the configuration of an electronic component built-in substrate will be described using as an example an embodiment in which the configuration on the first main surface side and the second main surface side of the core substrate is symmetrical.

[0036] FIG. 3 is a cross-sectional view schematically illustrating an example of an electronic component-embedded substrate having a built-in multilayer ceramic capacitor. The electronic component-embedded substrate 101 illustrated in FIG. 3 includes a core substrate 110. The core substrate 110 has a first surface 111 and a second surface 112 opposite the first surface 111, and an opening 120 is provided inside the core substrate 110. A multilayer ceramic capacitor 1 is provided in the opening 120. The core substrate may have multiple openings. A multilayer ceramic electronic component may be provided in each opening. The number of multilayer ceramic electronic components provided in each opening may be one or more. The number of multilayer ceramic electronic components provided in different openings may differ. FIG. 3 illustrates an embodiment in which multiple openings 120 are provided in the core substrate 110, and a multilayer ceramic capacitor 1 is provided in each opening 120. In this manner, a capacitor array having multiple built-in multilayer ceramic capacitors may be formed in the electronic component-embedded substrate.

[0037] The core substrate 110 may be a resin substrate, a glass substrate, a ceramic substrate, or the like. The core substrate 110 may be a printed wiring board having conductor wiring on its surface or inside. A preferred core substrate 110 is an insulating support substrate (core material) formed from a resin such as epoxy resin and a reinforcing material such as glass cloth. The support substrate may contain inorganic particles such as silica particles and alumina particles.

[0038] The first surface 111 and the second surface 112 of the core substrate 110 are parallel to each other and constitute a pair of opposing main surfaces of the core substrate 110 .

[0039] Opening 120 of core substrate 110 penetrates core substrate 110. The shape of opening 120 when core substrate 110 is viewed in plan is not particularly limited, and may be rectangular, circular, elliptical, oblong, n-sided (n is an integer of 5 or more), or the like.

[0040] The multilayer ceramic capacitor 1 is arranged in the opening 120 so that the first external electrode 51 is located on the first surface 111 side of the core substrate 110 and the second external electrode 52 is located on the second surface 112 side of the core substrate 110 .

[0041] When the multilayer ceramic capacitor (multilayer ceramic electronic component) is disposed in the opening, the first direction is a direction perpendicular to the second surface of the core substrate and toward the first surface, and when viewed as a multilayer ceramic electronic component, the multilayer ceramic capacitor has first external electrodes in the first direction and second external electrodes in a second direction opposite to the first direction.

[0042] The sealing material 130 is provided between the opening 120 and the multilayer ceramic electronic component (multilayer ceramic capacitor 1), on the first external electrode 51 and the first surface 111 of the core substrate 110, and on the second external electrode 52 and the second surface 112 of the core substrate 110. The surface of the sealing material 130 facing the first surface 111 of the core substrate 110 is a third surface 133, and the surface facing the second surface 112 of the core substrate 110 is a fourth surface 134.

[0043] Regarding the terms "on the second external electrode" and "on the second surface of the core substrate," the drawings depict the sealing material below the second external electrode and below the second surface of the core substrate, but the term "above" here does not indicate a top-bottom positional relationship, but is used to mean that the sealing material covers the second external electrode and the sealing material covers the second surface of the core substrate.

[0044] The first via conductor 141 penetrates the third surface 133 of the sealing material 130 and is electrically connected to the first external electrode 51 of the multilayer ceramic electronic component (multilayer ceramic capacitor 1). The second via conductor 142 penetrates the fourth surface 134 of the sealing material 130 and is electrically connected to the second external electrode 52 of the multilayer ceramic electronic component (multilayer ceramic capacitor 1). The first via conductor 141 and the second via conductor 142 are preferably formed by metal plating, and are preferably via conductors formed by Cu plating.

[0045] The dimensions of the components constituting the electronic component-embedded substrate of the present invention are described below. In the electronic component-embedded substrate of the present invention, the thickness A1 of the lead portion on the first end face side in the first direction is greater than the thickness B1 of the first external electrode. It is also preferable that the thickness A2 of the lead portion on the second end face side in the second direction is greater than the thickness B2 of the second external electrode. Below, an example is described in which the thickness A1 of the lead portion on the first end face side in the first direction is greater than the thickness B1 of the first external electrode, and the thickness A2 of the lead portion on the second end face side in the second direction is greater than the thickness B2 of the second external electrode. In this specification, the thickness (height) of each measurement site is defined as the average of measurements taken at five or more points.

[0046] In Figure 3, thicknesses A1, B1, A2, and B2 are indicated by double-headed arrows. In this specification, the "thickness of the external electrodes" refers to the thickness of the first external electrode at the first end face of the laminate and the thickness of the second external electrode at the second end face. The thicknesses of the external electrodes on other surfaces of the laminate are also distinguished. When forming the first and second via conductors, holes are drilled in the sealing material using a laser. The heat generated during the laser drilling is transferred to the multilayer ceramic electronic component via the external electrodes. Because the external electrodes are made of a metal material and the lead portions of the multilayer ceramic electronic component are primarily made of a ceramic material, the thermal conductivity of the lead portions is lower than that of the external electrodes. Therefore, if the lead portions are thick, the heat applied to the external electrodes by the laser is less likely to be transferred to the active portion inside the lead portions, thereby reducing damage to the active portion. Because the functionality of a multilayer ceramic electronic component is achieved by the active portion, it is important to reduce damage to the active portion. Furthermore, because the lead portions are primarily made of ceramic material and the effective portion contains a higher proportion of metal material than the lead portions, the thermal conductivity of the lead portions is lower than that of the effective portion. One way to reduce heat transfer to the effective portion is to increase the thickness of the external electrodes, but because external electrodes have high thermal conductivity, the effect of reducing heat conduction is limited even if the external electrodes are thickened. Therefore, increasing the thickness of the lead portions of multilayer ceramic electronic components is advantageous from the perspective of reducing the overall thickness of the electronic component-embedded substrate.

[0047] Furthermore, when the first and second via conductors are formed by plating, the multilayer ceramic electronic component is immersed in a plating solution while embedded in the core substrate. Ceramics have higher chemical stability against plating solutions than metals. Damage to the active portion caused by the plating solution when it reaches the multilayer ceramic electronic component can be reduced by increasing the thickness of the lead-out portion of the multilayer ceramic electronic component.

[0048] With regard to the thicknesses A1, B1, A2, and B2, it is preferable that the thickness A1 of the lead portion on the first end face side is at least twice the thickness B1 of the first external electrode. Furthermore, it is preferable that the thickness A2 of the lead portion on the second end face side is at least twice the thickness B2 of the second external electrode. When this relationship is satisfied, the effect of reducing damage to the active portion can be further enhanced. Furthermore, the overall thickness of the electronic component-embedded substrate can be made thinner than if the external electrodes were thicker to achieve the same level of damage reduction effect. Furthermore, the thickness A1 of the lead portion on the first end face side may be no more than four times the thickness B1 of the first external electrode, and the thickness A2 of the lead portion on the second end face side may be no more than four times the thickness B2 of the second external electrode.

[0049] The thickness A1 of the lead portion on the first end face side and the thickness A2 of the lead portion on the second end face side are each preferably 10 μm or more and 100 μm or less. The thickness B1 of the first external electrode and the thickness B2 of the second external electrode are each preferably 20 μm or more and 80 μm or less. They are also preferably 2 μm or more and 20 μm or less. As an example, thicknesses A1 and A2 can be 40 μm, and thicknesses B1 and B2 can be 30 μm. Alternatively, thicknesses A1 and A2 can be 40 μm, and thicknesses B1 and B2 can be 15 μm.

[0050] In the electronic component-embedded substrate of the present invention, it is preferable that the first external electrode extends to a surface adjacent to the first end face of the laminate, and that a thickness C1 of the external electrode in a direction perpendicular to the first direction on that surface is smaller than a thickness B1 of the first external electrode at the first end face. Furthermore, it is preferable that the second external electrode extends to a surface adjacent to the second end face of the laminate, and that a thickness C2 of the external electrode in a direction perpendicular to the second direction on that surface is smaller than a thickness B2 of the second external electrode at the second end face.

[0051] FIG. 4 is an explanatory diagram of thicknesses B1, C1, B2, and C2. In FIG. 4, thicknesses B1, C1, B2, and C2 are each indicated by a double-headed arrow. The surfaces adjacent to the first end face and second end face of the laminate are the first main face, second main face, first side face, and second side face of the laminate, respectively. While the drawings (FIGS. 2, 4, etc.) show the first main face 11 and second main face 12 of the laminate as the surfaces on which thicknesses C1 and C2 are measured, similar thicknesses C1 and C2 can also be measured on the first side face 13 and second side face 14.

[0052] The external electrodes extending to the surfaces adjacent to the first and second end faces of the laminate are external electrodes extending toward the effective portion. Heat conduction occurs from these external electrodes extending to the surfaces toward the effective portion inside the laminate. By reducing the thickness (volume) of these external electrodes, heat applied to the external electrodes by the laser is prevented from being transmitted to the side surfaces and main surfaces of the laminate via the external electrodes. This prevents the heat from being transmitted to the effective portion. Furthermore, by reducing the thickness of the external electrodes on the surfaces where via conductors are not formed, the layout density of the multilayer ceramic electronic component can be increased.

[0053] Regarding thicknesses B1, C1, B2, and C2, it is preferable that thickness B1 is not more than 5 times thickness C1, and thickness B2 is not more than 5 times thickness C2. If this relationship is satisfied, the effect of reducing damage to the effective portion can be further enhanced. Alternatively, thickness B1 may be not less than 1.5 times thickness C1, and thickness B2 may be not less than 1.5 times thickness C2.

[0054] The thickness C1 of the external electrode on the surface adjacent to the first end face of the laminate and the thickness C2 of the external electrode on the surface adjacent to the second end face of the laminate are each preferably 1 μm or more and 50 μm or less. The thickness B1 of the first external electrode and the thickness B2 of the second external electrode are each preferably 2 μm or more and 80 μm or less. As an example, the thicknesses C1 and C2 can be 10 μm, and the thicknesses B1 and B2 can be 30 μm.

[0055] Furthermore, it is preferable that the first and second external electrodes are external electrodes formed by applying and drying a metal paste, but when external electrodes are formed by applying a metal paste to the end faces of the laminate, it is easy to reduce the thickness of the external electrodes formed on the surfaces adjacent to the end faces of the laminate. Therefore, it is preferable that the first and second external electrodes are external electrodes formed by applying and drying a metal paste, and that the thickness C1 is smaller than the thickness B1 and the thickness C2 is smaller than the thickness B2.

[0056] In the electronic component-embedded substrate of the present invention, the thickness A1 of the drawn-out portion on the first end face side is preferably greater than the thickness D1 of the ineffective portion, which is a portion that is not a valid portion and exists inside the four surfaces adjacent to the first end face of the laminate, in a direction perpendicular to the first direction.Furthermore, the thickness A2 of the drawn-out portion on the second end face side is preferably greater than the thickness D2 of the ineffective portion, which is a portion that is not a valid portion and exists inside the four surfaces adjacent to the second end face of the laminate, in a direction perpendicular to the second direction.

[0057] Fig. 5 is an explanatory diagram of thicknesses A1, D1, A2, and D2. In Fig. 5, thicknesses A1, D1, A2, and D2 are each indicated by a double-headed arrow. The thickness of the ineffective portion is the thickness of a portion that is present inside a surface (either the first main surface, the second main surface, the first side surface, or the second side surface) adjacent to the end face of the laminate and does not become an effective portion. Fig. 5 shows thicknesses D1 and D2 in the LT cross section, but thicknesses D1 and D2 can also be defined as the distance from the end of the internal electrode layer to the side surface in the LW cross section.

[0058] The thicknesses equivalent to thicknesses D1 and D2 can be set at two locations on this LT cross section. It is possible to arbitrarily set which of these two locations, D1 or D2, is compared with thicknesses A1 and A2. Usually, thicknesses D1 and D2 are almost the same, and thicknesses A1 and A2 are also almost the same, so the conclusion is almost the same regardless of the combination.

[0059] The ineffective portion defined here is not a portion to which heat applied during laser drilling is directly transferred. Therefore, by reducing the thickness of this portion, the size of the multilayer ceramic electronic component can be reduced, and the arrangement density of the multilayer ceramic electronic component can be increased.

[0060] Regarding the thicknesses A1, D1, A2, and D2, it is preferable that the thickness A1 is 1.2 times or more the thickness D1, and the thickness A2 is 1.2 times or more the thickness D2. Alternatively, the thickness A1 may be 4 times or less the thickness D1, and the thickness A2 may be 4 times or less the thickness D2.

[0061] The thickness A1 of the drawn-out portion on the first end face side and the thickness A2 of the drawn-out portion on the second end face side are each preferably 10 μm or more and 100 μm or less. Furthermore, the thickness D1 of the ineffective portion, which is a portion that does not become an effective portion and exists inside the four surfaces adjacent to the first end face of the laminate, and the thickness D2 of the ineffective portion, which is a portion that does not become an effective portion and exists inside the four surfaces adjacent to the second end face of the laminate, are each preferably 2 μm or more and 50 μm or less. As an example, thicknesses A1 and A2 can be 40 μm, and thicknesses D1 and D2 can be 30 μm.

[0062] In the electronic component-embedded substrate of the present invention, the thickness A1 of the lead portion on the first end face side is preferably at least ¼ of the height E1 of the first via conductor, and the thickness A2 of the lead portion on the second end face side is preferably at least ¼ of the height E2 of the second via conductor.

[0063] Fig. 6 is an explanatory diagram of thicknesses A1, A2 and heights E1, E2, in which thicknesses A1, A2 and heights E1, E2 are indicated by double-headed arrows.

[0064] The higher the via conductor, the greater the heat generated by drilling holes in the encapsulant with a laser. Therefore, by making the thickness of the lead-out portion on the end face sufficiently thick relative to the height of the via conductor, damage to the effective portion can be reduced even when the via conductor is high and the heat generated by drilling holes with a laser is large. Furthermore, the higher the via conductor, the greater the amount of resin processing required, which increases the heat generated by the laser, and an over-processing margin is also required. Therefore, it is preferable that the height of the via conductor is low, which is indicated by the ratio of the thicknesses A1 and A2 to the heights E1 and E2 being 1 / 4 or more.

[0065] Regarding the thicknesses A1 and A2 and the heights E1 and E2, it is preferable that the ratio of the thickness A1 to the height E1 is 1 / 2 or more, and the ratio of the thickness A2 to the height E2 is 1 / 2 or more. If this relationship is satisfied, damage to the effective portion can be further reduced. Alternatively, the ratio of the thickness A1 to the height E1 may be 1 or less, and the ratio of the thickness A2 to the height E2 may be 1 or less.

[0066] The thickness A1 of the lead portion on the first end face side and the thickness A2 of the lead portion on the second end face side are each preferably 10 μm or more and 100 μm or less. The height E1 of the first via conductor and the height E2 of the second via conductor are each preferably 20 μm or more and 140 μm or less. For example, the thicknesses A1 and A2 can be 40 μm, and the heights E1 and E2 can be 70 μm.

[0067] Up to this point, an example of an electronic component-embedded substrate provided with a multilayer ceramic capacitor as a multilayer ceramic electronic component has been described, but the multilayer ceramic electronic component is not limited to a multilayer ceramic capacitor. Another example is a multilayer ceramic coil. When the multilayer ceramic electronic component is a multilayer ceramic coil, the effective portion is a coil portion in which wiring is wound in a coil shape and produces an inductor component, and the drawn-out portion is a drawn-out conductor portion where the coil portion is drawn out to an end face of the laminate. An example of a multilayer ceramic coil will be described below.

[0068] 7 is an LT cross-sectional view schematically showing an example of an electronic component built-in substrate provided with a multilayer ceramic coil as a multilayer ceramic electronic component. Fig. 7 shows an electronic component built-in substrate 102 in which a multilayer ceramic coil 2 is provided in an opening 120. The multilayer ceramic coil 2 shown in Fig. 7 is a so-called "horizontal wound" coil.

[0069] The laminated ceramic coil 2 has a stacking direction in which the first external electrode and the second external electrode face each other, and includes a first extended conductor 71 connected to the first external electrode 51, a second extended conductor 72 connected to the second external electrode 52, and a coil section 60 located between the first extended conductor 71 and the second extended conductor 72 and having wiring wound in a coil shape to produce an inductor component. The coil section 60 is an effective section 30 that functions as an electronic component, and the first extended conductor 71 and the second extended conductor 72 are the first extended section 31 and the second extended section 32, respectively.

[0070] The thicknesses A1, A2, B1, B2, C1, C2, D1, and D2 of the multilayer ceramic coil 2 can be determined in the same manner as the multilayer ceramic capacitor 1. These dimensions are illustrated in FIG. 7 . The heights E1 and E2 of the via conductors can also be determined in the same manner as the electronic component-embedded substrate provided with the multilayer ceramic capacitor. The preferred ranges for the relationships of these dimensions can also be set to be the same as those for the electronic component-embedded substrate provided with the multilayer ceramic capacitor, and the effects achieved by satisfying the dimensional relationships are similarly achieved.

[0071] 8 is an LT cross-sectional view schematically showing another example of an electronic component built-in substrate provided with a multilayer ceramic coil as a multilayer ceramic electronic component. Fig. 8 shows an electronic component built-in substrate 103 in which a multilayer ceramic coil 3 is provided in an opening 120. The multilayer ceramic coil 3 shown in Fig. 8 is a so-called "vertical wound" coil.

[0072] The laminated ceramic coil 3 has a stacking direction orthogonal to the direction in which the first external electrode and the second external electrode oppose each other (the direction in which the first principal surface and the second principal surface oppose each other). The laminated ceramic coil 3 includes a first extended conductor 71 connected to the first external electrode 51, a second extended conductor 72 connected to the second external electrode 52, and a coil section 60 located between the first extended conductor 71 and the second extended conductor 72 and having wiring wound in a coil shape to produce an inductor component. The coil section 60 is an effective section 30 that functions as an electronic component, and the first extended conductor 71 and the second extended conductor 72 are the first extended section 31 and the second extended section 32, respectively.

[0073] The thicknesses A1, A2, B1, B2, C1, C2, D1, and D2 of the multilayer ceramic coil 3 can be determined in the same manner as the multilayer ceramic capacitor 1. These dimensions are illustrated in FIG. 8 . The heights E1 and E2 of the via conductors can also be determined in the same manner as the electronic component-embedded substrate provided with the multilayer ceramic capacitor. The preferred ranges for the relationships of these dimensions can also be set to be the same as those for the electronic component-embedded substrate provided with the multilayer ceramic capacitor, and the effects achieved by satisfying the dimensional relationships are similarly achieved.

[0074] Furthermore, a single electronic component-embedded substrate may contain multiple types of multilayer ceramic electronic components, such as a multilayer ceramic capacitor and a multilayer ceramic coil, or a multilayer ceramic coil that is vertically wound and horizontally wound.

[0075] The method for manufacturing an electronic component-embedded substrate of the present invention includes the steps of: preparing a core substrate having a first surface and a second surface opposite to the first surface and having an opening formed therein; arranging a multilayer ceramic electronic component for use in the electronic component-embedded substrate of claim 1, the multilayer ceramic electronic component having a first external electrode in a first direction perpendicular to the second surface of the core substrate and extending toward the first surface, and a second external electrode in a second direction opposite to the first direction; providing a sealing material between the opening and the multilayer ceramic electronic component, on the first external electrode, and on the first surface, sealing the opening; forming a via hole through a third surface of the sealing material that is the surface of the sealing material located on the first surface side, by laser processing; and providing a first via conductor electrically connected to the first external electrode of the multilayer ceramic electronic component by plating the via hole. In the method for manufacturing an electronic component-embedded substrate of the present invention, a sealing material may further be provided on the second external electrode and the second surface, and via holes penetrating a fourth surface of the sealing material, which is the surface of the sealing material provided on the second surface side, may be provided by laser processing, and second via conductors electrically connected to the second external electrodes of the multilayer ceramic electronic component may be provided in the via holes by plating. Below, an example of an embodiment in which a sealing material is also provided on the second external electrode and the second surface, and second via conductors are provided will be described.

[0076] The multilayer ceramic electronic component is manufactured so that the dimensions of the active portion and the lead portion are predetermined, and so that the thickness of the external electrodes is predetermined. By employing a method of dipping the end faces of the laminate in a conductive paste when forming the external electrodes, the thickness of the external electrodes at the end faces can be reduced. Furthermore, the thickness of the external electrodes extending to the surfaces adjacent to the first and second end faces of the laminate can be reduced. It is preferable to use a Cu paste containing Cu as a metal and glass as the conductive paste.

[0077] 9, 10, 11, 12, and 13 are process diagrams that schematically show the manufacturing process of an electronic component-embedded substrate. First, as shown in Fig. 9, a core substrate 110 is drilled with a drill or the like to form an opening 120 that penetrates from a first surface 111 to a second surface 112 of the core substrate 110. This prepares a core substrate that has a first surface and a second surface opposite to the first surface and has an opening provided therein.

[0078] 10 , the core substrate 110 is placed on the carrier tape 150, and the multilayer ceramic capacitor 1 (multilayer ceramic electronic component) is arranged in the opening. This results in the multilayer ceramic electronic component having first external electrodes in a first direction that is perpendicular to the second surface of the core substrate and toward the first surface, and having second external electrodes in a second direction opposite to the first direction.

[0079] 11 , a sealing material 130 is provided between the opening 120 and the multilayer ceramic capacitor 1, on the first external electrode 51 and the first surface 111 of the core substrate 110, and on the second external electrode 52 and the second surface 112 of the core substrate 110. The surface of the sealing material 130 facing the first surface 111 becomes a third surface 133 of the sealing material, and the surface facing the second surface 112 becomes a fourth surface 134 of the sealing material.

[0080] 12 and 13 , via holes 161 penetrating the third surface 133 of the encapsulant are formed by laser processing, and first via conductors 141 electrically connected to the first external electrodes 51 of the multilayer ceramic capacitor 1 are formed in the via holes 161 by plating. Similarly, via holes 162 penetrating the fourth surface 134 of the encapsulant are formed by laser processing, and second via conductors 142 electrically connected to the second external electrodes 52 of the multilayer ceramic capacitor 1 are formed in the via holes 162 by plating. At the same time as forming the first via conductors 141 and second via conductors 142, wiring 143 may be formed on the third surface 133 and the fourth surface 134 of the encapsulant by plating. By the above method, the electronic component built-in substrate 101 is manufactured.

[0081] The multilayer ceramic electronic component used in the manufacturing method of the electronic component-embedded substrate is designed so that the thicknesses A1 and A2 of the lead portions are greater than the thicknesses B1 and B2 of the external electrodes. This allows the manufacturing of an electronic component-embedded substrate while reducing damage to the effective portion of the multilayer ceramic electronic component when drilling via holes by laser processing. Furthermore, damage to the effective portion by a plating solution when forming via conductors in the via holes by plating can be reduced.

[0082] The present specification discloses the following:

[0083] <1> An electronic component-embedded substrate comprising: a core substrate having a first surface and a second surface opposite to the first surface, and having an opening provided therein; a multilayer ceramic electronic component provided in the opening, the multilayer ceramic electronic component having a first external electrode in a first direction perpendicular to the second surface of the core substrate and extending toward the first surface, and a second external electrode in a second direction opposite to the first direction; a sealing material provided between the opening and the multilayer ceramic electronic component, on the first external electrode and on the first surface, the sealing material having a third surface on the first surface side; and a first via conductor penetrating the third surface of the sealing material and electrically connected to the first external electrode of the multilayer ceramic electronic component, wherein the multilayer ceramic electronic component has a laminate in a substantially rectangular parallelepiped shape having a first end face and a second end face opposite to the first end face, the first external electrode provided on the first end face, and the second external electrode provided on the second end face, The laminate comprises an effective portion in which a plurality of internal electrode layers are overlapped and which functions as an electronic component, and an extraction portion that extracts the internal electrode layers from the effective portion to the first external electrode, and a thickness A1 of the extraction portion on the first end face side in a direction along the first direction is thicker than a thickness B1 of the first external electrode.

[0084] <2> The electronic component-embedded substrate according to <1>, wherein a thickness A1 of the lead portion on the first end face side is at least twice a thickness B1 of the first external electrode.

[0085] <3> The electronic component-embedded substrate according to <1> or <2>, wherein the first external electrode extends to a surface adjacent to the first end face of the laminate, and a thickness C1 of the external electrode on the surface in a direction perpendicular to the direction along the first direction is smaller than a thickness B1 of the first external electrode at the first end face.

[0086] <4> The electronic component-embedded substrate according to any one of <1> to <3>, wherein a thickness A1 of the drawn-out portion on the first end face side is thicker than a thickness D1 in a direction perpendicular to the direction along the first direction of a non-effective portion that is present inside four surfaces adjacent to the first end face of the laminate and does not become the effective portion.

[0087] <5> The electronic component-embedded substrate according to any one of <1> to <4>, wherein a thickness A1 of the drawn-out portion on the first end face side is equal to or greater than ¼ of a height E1 of the first via conductor.

[0088] <6> The electronic component-embedded substrate according to any one of <1> to <5>, wherein the thermal conductivity of the lead-out portion is lower than the thermal conductivity of the effective portion.

[0089] <7> The electronic component-embedded substrate according to any one of <1> to <6>, wherein the first external electrodes and the second external electrodes are made of only Cu paste.

[0090] <8> The electronic component built-in substrate according to any one of <1> to <7>, wherein the first external electrode and the second external electrode contain Cu and glass.

[0091] <9> The electronic component-embedded substrate according to any one of <1> to <8>, wherein the core substrate is provided with a plurality of the openings.

[0092] <10> The electronic component-embedded substrate according to any one of <1> to <9>, wherein the multilayer ceramic electronic component is a multilayer ceramic capacitor, the effective portion is a capacitive portion where a first internal electrode layer drawn to the first end face side of the laminate and a second internal electrode layer drawn to the second end face side of the laminate overlap, and whereby electrostatic capacitance is exhibited, and the drawn-out portion is a non-capacitive portion where the first internal electrode layer is drawn to the first end face of the laminate.

[0093] <11> The electronic component-embedded substrate according to any one of <1> to <9>, wherein the multilayer ceramic electronic component is a multilayer ceramic coil, the effective portion is a coil portion in which wiring is wound in a coil shape and which exhibits an inductor component, and the drawn-out portion is a drawn-out conductor portion in which the coil portion is drawn out to a first end face of the laminate.

[0094] <12> A method for manufacturing an electronic component-embedded substrate, comprising: preparing a core substrate having a first surface and a second surface opposite to the first surface, and having an opening provided therein; arranging, in the opening, a multilayer ceramic electronic component to be used in the electronic component-embedded substrate according to any one of <1> to <11>, the multilayer ceramic electronic component having a first external electrode in a first direction that is orthogonal to the second surface of the core substrate and toward the first surface, and a second external electrode in a second direction opposite to the first direction; providing a sealing material between the opening and the multilayer ceramic electronic component, on the first external electrode, and on the first surface, for sealing; providing, by laser processing, a via hole that penetrates a third surface of the sealing material that is a surface of the sealing material provided on the first surface side; and providing, in the via hole, a first via conductor that is electrically connected to the first external electrode of the multilayer ceramic electronic component by plating.

[0095] REFERENCE SIGNS LIST 1 Multilayer ceramic capacitor (multilayer ceramic electronic component) 2 Vertically wound multilayer ceramic coil (multilayer ceramic electronic component) 3 Horizontally wound multilayer ceramic coil (multilayer ceramic electronic component) 10 Laminate 11 First main surface of laminate 12 Second main surface of laminate 13 First side surface of laminate 14 Second side surface of laminate 15 First end surface of laminate 16 Second end surface of laminate 20 Dielectric ceramic layer 21 First internal electrode layer (internal electrode layer) 22 Second internal electrode layer (internal electrode layer) 30 Effective portion 31 First lead portion 32 Second lead portion 51 First external electrode 52 Second external electrode 60 Coil portion 71 First lead conductor portion 72 Second lead conductor portion 101, 102, 103 Electronic component built-in substrate 110 Core substrate 111 First surface of core substrate 112 Second surface of core substrate 120 Opening 130 Sealing material 133 Third surface of sealing material 134 Fourth surface of sealing material 141 First via conductor 142 Second via conductor 143 Wiring on sealing material 150 Carrier tape 161 Via hole (via hole in which first via conductor is provided) 162 Via hole (via hole in which second via conductor is provided)

Claims

1. An electronic component-embedded substrate comprising: a core substrate having a first surface and a second surface opposite to the first surface, and having an opening provided therein; a multilayer ceramic electronic component provided in the opening, having a first external electrode in a first direction perpendicular to the second surface of the core substrate and toward the first surface, and a second external electrode in a second direction opposite to the first direction; a sealing material provided between the opening and the multilayer ceramic electronic component, on the first external electrode and on the first surface, and having a third surface facing the first surface; and a first via conductor that penetrates the third surface of the sealing material and is electrically connected to the first external electrode of the multilayer ceramic electronic component, wherein the multilayer ceramic electronic component has a laminate in a substantially rectangular parallelepiped shape having a first end face and a second end face opposite to the first end face, the first external electrode provided on the first end face, and the second external electrode provided on the second end face, The laminate comprises an effective portion in which a plurality of internal electrode layers are overlapped and which functions as an electronic component, and an extraction portion that extracts the internal electrode layers from the effective portion to the first external electrode, and a thickness A1 of the extraction portion on the first end face side in a direction along the first direction is thicker than a thickness B1 of the first external electrode.

2. The electronic component built-in substrate according to claim 1, wherein the thickness A1 of the lead portion on the first end face side is at least twice the thickness B1 of the first external electrode.

3. An electronic component-embedded substrate as described in claim 1 or 2, wherein the first external electrode extends to a surface adjacent to the first end face of the laminate, and a thickness C1 of the external electrode on that surface in a direction perpendicular to the direction along the first direction is smaller than a thickness B1 of the first external electrode at the first end face.

4. An electronic component-embedded substrate as described in any one of claims 1 to 3, wherein the thickness A1 of the drawn-out portion on the first end face side is thicker than the thickness D1 in a direction perpendicular to the first direction of the ineffective portion, which is the portion that does not become the effective portion and exists inside the four surfaces adjacent to the first end face of the laminate.

5. An electronic component-embedded substrate according to any one of claims 1 to 4, wherein the thickness A1 of the lead-out portion on the first end face side is 1 / 4 or more of the height E1 of the first via conductor.

6. The electronic component built-in substrate according to any one of claims 1 to 5, wherein the thermal conductivity of the lead-out portion is lower than the thermal conductivity of the effective portion.

7. The electronic component built-in substrate according to any one of claims 1 to 6, wherein the first external electrode and the second external electrode are made of Cu paste only.

8. The electronic component built-in substrate according to any one of claims 1 to 7, wherein the first external electrode and the second external electrode contain Cu and glass.

9. The electronic component built-in substrate according to any one of claims 1 to 8, wherein a plurality of openings are provided in the core substrate.

10. An electronic component-embedded substrate according to any one of claims 1 to 9, wherein the multilayer ceramic electronic component is a multilayer ceramic capacitor, the effective portion is a capacitive portion that exhibits capacitance, where a first internal electrode layer that is drawn out to the first end face side of the laminate and a second internal electrode layer that is drawn out to the second end face side of the laminate overlap, and the drawn-out portion is a non-capacitive portion where the first internal electrode layer is drawn out to the first end face of the laminate.

11. An electronic component-embedded substrate according to any one of claims 1 to 9, wherein the multilayer ceramic electronic component is a multilayer ceramic coil, the effective portion is a coil portion in which wiring is wound in a coil shape to produce an inductor component, and the drawn-out portion is a drawn-out conductor portion in which the coil portion is drawn out to a first end face of the laminate.

12. A method for manufacturing an electronic component-embedded substrate, comprising: preparing a core substrate having a first surface and a second surface opposite to the first surface, and having an opening formed therein; arranging within the opening a multilayer ceramic electronic component to be used in the electronic component-embedded substrate according to any one of claims 1 to 11, the multilayer ceramic electronic component having a first external electrode in a first direction perpendicular to the second surface of the core substrate and toward the first surface, and a second external electrode in a second direction opposite to the first direction; providing a sealing material between the opening and the multilayer ceramic electronic component, on the first external electrode, and on the first surface, for sealing; providing by laser processing a via hole penetrating a third surface of the sealing material, which is the surface of the sealing material provided on the first surface side; and providing a first via conductor electrically connected to the first external electrode of the multilayer ceramic electronic component by plating in the via hole.

Images