Electronic component–embedded substrate and composite component

Abstract

This electronic component–embedded substrate 1 comprises: a core layer 10 having a cavity 15 penetrating in the thickness direction; an electronic component 20 embedded in the cavity 15 of the core layer 10; an insulating layer 30 provided so as to cover the core layer 10 and the electronic component 20 from both sides in the thickness direction and having a first surface 31 and a second surface 32 facing each other in the thickness direction; a through conductor 40 provided so as to penetrate the core layer 10 in the thickness direction; and a conductor interconnection layer 50 provided on a part of the first surface 31 and / or the second surface 32 of the insulating layer 30. The first surface 31 of the insulating layer 30 is a component mounting surface and the second surface 32 of the insulating layer 30 is an external terminal surface, or the first surface 31 of the insulating layer 30 is an external terminal surface and the second surface 32 of the insulating layer 30 is a component mounting surface. When a first region RG1 is defined as the region from a central plane 35 between the first surface 31 and the second surface 32 in the thickness direction to the outermost surface on the first surface 31 side and a second region RG2 is defined as the region from the central plane 35 to the outermost surface on the second surface 32 side, the coefficient of thermal expansion of the second region RG2 is higher than the coefficient of thermal expansion of the first region RG1.

Description

Electronic component embedded boards and composite components

[0001] The present invention relates to a substrate with built-in electronic components and a composite component.

[0002] Patent Document 1 discloses a package substrate used in a semiconductor composite device that supplies a load with a DC voltage regulated by a voltage regulator including a semiconductor active element. The package substrate described in Patent Document 1 includes a first layer on which a capacitor is formed, a second layer different from the first layer on which an inductor is formed, and a connection terminal disposed on the mounting surface of the package substrate and used for electrical connection to the voltage regulator and the load. The package substrate has first and second through holes formed therein that penetrate the first and second layers in a direction perpendicular to the mounting surface. The capacitor is electrically connected to the load via the first through hole. The inductor is electrically connected to the load via the first through hole and electrically connected to the voltage regulator via the second through hole.

[0003] International Publication No. 2019 / 130746

[0004] However, when an electronic component-embedded substrate such as the package substrate described in Patent Document 1 is mounted on a motherboard with mounted components, the electronic component-embedded substrate is prone to warping due to differences in the thermal expansion coefficients of the electronic component-embedded substrate, the mounted components, and the motherboard. This warping can cause poor connection between the electronic component-embedded substrate and the motherboard.

[0005] The present invention has been made to solve the above problems, and aims to provide a substrate with built-in electronic components that can reduce warpage when mounted on a motherboard with mounted components, and a composite component in which mounted components are mounted on the above-mentioned substrate with built-in electronic components.

[0006] The electronic component-embedded substrate of the present invention includes a core layer having a cavity penetrating therethrough in a thickness direction, an electronic component embedded in the cavity of the core layer, an insulating layer provided to cover the core layer and the electronic component from both sides in the thickness direction and having a first surface and a second surface opposing each other in the thickness direction, a through conductor provided to penetrate the core layer in the thickness direction, and a conductor wiring layer provided on a portion of at least one of the first surface and the second surface of the insulating layer. The first surface of the insulating layer is a component mounting surface, and the second surface of the insulating layer is an external terminal surface, or the first surface of the insulating layer is the external terminal surface, and the second surface of the insulating layer is the component mounting surface. When a first region is defined as a region between a central plane between the first surface and the second surface in the thickness direction and a region from the central plane to the outermost surface on the first surface side, and a second region is defined as a region from the central plane to the outermost surface on the second surface side, the thermal expansion coefficient of the second region is greater than that of the first region.

[0007] In a first aspect, the composite component of the present invention comprises the electronic component-embedded substrate of the present invention and a mounting component mounted on the first surface of the insulating layer, wherein the thermal expansion coefficient of the mounting component is equal to or greater than the thermal expansion coefficient of the second region.

[0008] In a second aspect, the composite component of the present invention comprises the electronic component-embedded substrate of the present invention and a mounting component mounted on the second surface of the insulating layer, wherein the thermal expansion coefficient of the mounting component is equal to or less than the thermal expansion coefficient of the first region.

[0009] According to the present invention, it is possible to provide a substrate with built-in electronic components that can reduce warpage when the substrate is mounted on a motherboard with mounted components. Furthermore, according to the present invention, it is possible to provide a composite component in which mounted components are mounted on the above-mentioned substrate with built-in electronic components.

[0010] FIG. 1 is a cross-sectional view schematically showing an example of an electronic component built-in substrate of the present invention. FIGS. 2A, 2B, and 2C are examples of schematic diagrams for explaining warpage of an electronic component built-in substrate according to a comparative example outside the scope of the present invention. FIGS. 3A, 3B, and 3C are examples of schematic diagrams for explaining warpage of an electronic component built-in substrate according to an example within the scope of the present invention. FIG. 4 is a cross-sectional view schematically showing an example of a composite part including an electronic component built-in substrate of the present invention. FIG. 5 is a cross-sectional view schematically showing an example of a capacitor element built into a cavity in a core layer constituting the electronic component built-in substrate of the present invention. FIG. 6 is an enlarged cross-sectional view of the portion indicated by VI in the capacitor element shown in FIG. 5.

[0011] The electronic component-embedded substrate and composite component of the present invention will be described below. Note that the present invention is not limited to the following embodiments and may be modified as appropriate within the scope of the present invention. Furthermore, a combination of multiple individual preferred configurations described in the following embodiments also constitutes the present invention.

[0012] In this specification, terms indicating the relationship between elements (e.g., "perpendicular," "parallel," "orthogonal," etc.) and terms indicating the shapes of elements are not expressions that only express a strict meaning, but are expressions that mean that a range of substantial equivalence, for example, a difference of about several percent, is also included. Furthermore, in this specification, "constant" is not an expression that means only when something is completely constant, but is an expression that means when something is substantially constant, for example, a difference of about several percent.

[0013] The drawings shown below are schematic diagrams, and the dimensions, aspect ratio, and other scales may differ from those of the actual product. In the drawings, the same or equivalent parts will be designated by the same reference numerals. In addition, the same elements will be designated by the same reference numerals in each drawing, and duplicate explanations will be omitted.

[0014] FIG. 1 is a cross-sectional view schematically showing an example of an electronic component built-in substrate of the present invention.

[0015] Although the overall configuration is not shown in FIG. 1, the electronic component built-in substrate 1 includes a core layer 10, an electronic component 20, an insulating layer 30, a through conductor 40, and a conductor wiring layer 50.

[0016] The core layer 10 has a cavity 15 penetrating in the thickness direction (vertical direction in FIG. 1).

[0017] The core layer 10 is made of an insulating material. The insulating material constituting the core layer 10 may contain glass cloth. By containing the glass cloth in the core layer 10, the rigidity of the entire substrate can be increased. The glass cloth is made by weaving glass yarns, for example, in a lattice pattern.

[0018] The core layer 10 is formed using, for example, a prepreg in which a glass cloth is pre-impregnated with an insulating resin.

[0019] 1 includes one core layer 10, but two or more core layers 10 may be included in the thickness direction. In that case, it is sufficient that at least one core layer 10 has a cavity 15.

[0020] The same core layer 10 may have multiple cavities 15. When two or more core layers 10 are included in the thickness direction, the number of cavities 15 in each core layer 10 may be the same, or some or all of the numbers may be different.

[0021] The electronic component 20 is embedded in the cavity 15 of the core layer 10. The type of electronic component 20 is not particularly limited, and examples thereof include a capacitor element. When the electronic component 20 is a capacitor element, the type of capacitor is not particularly limited, and may be, for example, an electrolytic capacitor, a multilayer ceramic capacitor, or a trench capacitor. When the electronic component-embedded substrate 1 includes multiple electronic components 20, a combination of different types of capacitors may be used.

[0022] The cavity 15 between the core layer 10 and the electronic component 20 is preferably filled with an insulating member 25 made of an insulating material such as an insulating resin. The insulating member 25 may be integral with the insulating layer 30.

[0023] A single cavity 15 may contain multiple electronic components 20. In this case, the multiple electronic components 20 may be lined up in the thickness direction or in a plane direction perpendicular to the thickness direction. The multiple electronic components 20 contained in the cavity 15 may or may not be electrically connected to each other.

[0024] The insulating layer 30 is provided so as to cover the core layer 10 and the electronic component 20 from both sides in the thickness direction. The insulating layer 30 has a first surface 31 and a second surface 32 that face each other in the thickness direction.

[0025] The first surface 31 of the insulating layer 30 is one of the component mounting surface and the external terminal surface, and the second surface 32 of the insulating layer 30 is the other of the component mounting surface and the external terminal surface. That is, the first surface 31 of the insulating layer 30 is the component mounting surface and the second surface 32 of the insulating layer 30 is the external terminal surface, or the first surface 31 of the insulating layer 30 is the external terminal surface and the second surface 32 of the insulating layer 30 is the component mounting surface.

[0026] Here, the component mounting surface is the surface on which mounted components are mounted, while the external terminal surface is the surface on which external terminals used for electrical connection with the motherboard are provided.

[0027] The insulating layer 30 is made of an insulating material. The insulating material that makes up the insulating layer 30 may be the same as or different from the insulating material that makes up the core layer 10.

[0028] The insulating layer 30 may be composed of only one layer or two or more layers. When the insulating layer 30 is composed of two or more layers, the materials constituting the layers may be the same or different.

[0029] The insulating layer 30 may be provided with via conductors 55 that are electrically connected to a wiring layer such as the conductor wiring layer 50. The conductor wiring layer 50 and the electronic component 20 may be electrically connected through the via conductors 55.

[0030] The through conductors 40 are provided so as to penetrate the core layer 10 in the thickness direction. As shown in Fig. 1 , the through conductors 40 may be provided so as to penetrate not only the core layer 10 but also the insulating layer 30 in the thickness direction. The through conductors 40 are electrically connected to, for example, the conductor wiring layer 50.

[0031] The through conductor 40 may be provided on at least the inner wall surface of the through hole that penetrates the core layer 10 in the thickness direction. That is, the through conductor 40 may be provided only on the inner wall surface of the through hole, or may be provided throughout the entire interior of the through hole.

[0032] Although not shown in Fig. 1, when the through conductor 40 is provided on the inner wall surface of the through hole penetrating the core layer 10 in the thickness direction, a resin filling portion filled with a resin material may be provided inside the through conductor 40. In this case, the resin filling portion is provided in the space surrounded by the through conductor 40 inside the through hole penetrating the core layer 10 in the thickness direction. When the space inside the through hole is eliminated by providing the resin filling portion, the occurrence of delamination of the through conductor 40 is suppressed. The resin filling portion may be a conductor or an insulator.

[0033] The number of through conductors 40 is not particularly limited, and may be one, or two or more.

[0034] The cross-sectional shape of the through conductor 40 perpendicular to the thickness direction is not particularly limited, and may be, for example, a circular shape.

[0035] The diameter of the through conductor 40 may be constant or may vary in the thickness direction. Note that the diameter of the through conductor 40 means the diameter when the planar shape is circular, and means the equivalent circle diameter when the planar shape is other than circular.

[0036] 1, the electronic component-embedded substrate 1 may be provided with a through conductor that penetrates the electronic component 20 in the thickness direction. In this case, the through conductor may be provided so as to penetrate not only the electronic component 20 but also the insulating layer 30 in the thickness direction.

[0037] The conductor wiring layer 50 is provided on a part of at least one of the first surface 31 and the second surface 32 of the insulating layer 30. That is, the conductor wiring layer 50 may be provided only on the first surface 31 of the insulating layer 30, only on the second surface 32 of the insulating layer 30, or on both the first surface 31 and the second surface 32 of the insulating layer 30.

[0038] For example, when the electronic component 20 includes a first electrode and a second electrode having different polarities, the conductor wiring layer 50 may include a first conductor wiring layer electrically connected to the first electrode of the electronic component 20, and a second conductor wiring layer electrically connected to the second electrode of the electronic component 20.

[0039] 1 , a wiring layer 60 may be provided on at least one main surface of the electronic component 20. For example, when the electronic component 20 includes a first electrode and a second electrode having different polarities, the wiring layer 60 may include a first wiring layer electrically connected to the first electrode of the electronic component 20 and a second wiring layer electrically connected to the second electrode of the electronic component 20.

[0040] In the electronic component built-in substrate 1, when a region from a central surface 35 between the first surface 31 and the second surface 32 in the thickness direction to the outermost surface on the first surface 31 side is defined as a first region RG1, and a region from the central surface 35 to the outermost surface on the second surface 32 side is defined as a second region RG2, the thermal expansion coefficient of the second region RG2 is larger than that of the first region RG1. In other words, when the thermal expansion coefficient of the first region RG1 is defined as CTE1 and the thermal expansion coefficient of the second region RG2 is defined as CTE2, the relationship CTE1<CTE2 is satisfied.

[0041] The "coefficient of thermal expansion (CTE)" refers to the coefficient of thermal expansion in the plane direction perpendicular to the thickness direction (the vertical direction in FIG. 1). The coefficient of thermal expansion of each region can be determined from the coefficient of thermal expansion of the material constituting the member present in each region.

[0042] As described above, when a conventional substrate with built-in electronic components is mounted on a motherboard, the substrate is prone to warping due to differences in the thermal expansion coefficients of the substrate with built-in electronic components, the mounted components, and the motherboard.

[0043] In contrast, in the electronic component built-in substrate 1, the thermal expansion coefficient CTE2 of the second region RG2 is greater than the thermal expansion coefficient CTE1 of the first region RG1, so that during mounting, the first surface 31 side of the insulating layer 30 warps concavely and the second surface 32 side warps convexly. Therefore, in the electronic component built-in substrate 1, by arranging the component mounting surface and the external terminal surface so as to offset the warping caused by the difference in the thermal expansion coefficients of the electronic component built-in substrate, the mounted components, and the motherboard, it is possible to reduce warping after mounting. As a result, it is possible to reduce connection failures between the electronic component built-in substrate and the motherboard.

[0044] 2A, 2B, and 2C are examples of schematic diagrams for explaining warpage of an electronic component built-in substrate according to a comparative example outside the scope of the present invention.

[0045] 2A, 2B, and 2C, a comparative example of an electronic component built-in substrate 1a outside the scope of the present invention is used. In this comparative example, due to differences in the thermal expansion coefficients of the electronic component built-in substrate 1a, the mounted component 2, and the motherboard 3, the component mounting surface of the electronic component built-in substrate 1a warps convexly and the external terminal surface warps concavely during mounting, as shown in Fig. 2C. Note that the electronic component built-in substrate 1a may also undergo a process in which the component mounting surface warps concavely and the external terminal surface warps convexly, as shown in Fig. 2B.

[0046] 3A, 3B, and 3C are examples of schematic diagrams for explaining warpage of an electronic component built-in substrate according to an example within the scope of the present invention.

[0047] 3A, 3B, and 3C use an electronic component built-in substrate 1 according to an embodiment within the scope of the present invention. In this embodiment, in order to reduce warpage in the direction shown in Fig. 2C, the thermal expansion coefficient of the external terminal surface side of the electronic component built-in substrate 1 is made larger than the thermal expansion coefficient of the component mounting surface side. This makes it possible to reduce warpage during mounting, as shown in Fig. 3C.

[0048] On the other hand, if the electronic component built-in substrate 1a, which is outside the scope of the present invention, warps in the opposite direction to that shown in Figure 2C, i.e., if the component mounting surface of the electronic component built-in substrate 1a warps concavely and the external terminal surface warps convexly, the thermal expansion coefficient of the component mounting surface side can be made larger than the thermal expansion coefficient of the external terminal surface side of the electronic component built-in substrate 1, which is within the scope of the present invention.

[0049] From the viewpoint of making the thermal expansion coefficient CTE2 of the second region RG2 larger than the thermal expansion coefficient CTE1 of the first region RG1, it is preferable that the thickness of the insulating layer 30 on the first surface 31 side (the length indicated by T1 in FIG. 1 ) is larger than the thickness of the insulating layer 30 on the second surface 32 side (the length indicated by T2 in FIG. 1 ), as shown in FIG. 1 . Alternatively, it is preferable that the electronic component 20 is disposed closer to the second surface 32 of the insulating layer 30 than to the first surface 31 of the insulating layer 30 in the thickness direction, as shown in FIG. 1 . In this case, it is preferable that the thermal expansion coefficient of the electronic component 20 is larger than the thermal expansion coefficient of the insulating layer 30.

[0050] Furthermore, from the viewpoint of making the thermal expansion coefficient CTE2 of the second region RG2 larger than the thermal expansion coefficient CTE1 of the first region RG1, it is preferable that the total area of ​​the conductor wiring layers 50 provided on the second surface 32 of the insulating layer 30 be larger than the total area of ​​the conductor wiring layers 50 provided on the first surface 31 of the insulating layer 30.

[0051] Alternatively, the method for making the thermal expansion coefficient CTE2 of the second region RG2 greater than the thermal expansion coefficient CTE1 of the first region RG1 is not particularly limited. For example, the number of via conductors 55 provided in the second region RG2 may be greater than the number of via conductors 55 provided in the first region RG1. In this case, the via conductors 55 may or may not be provided in the first region RG1.

[0052] FIG. 4 is a cross-sectional view schematically showing an example of a composite part including an electronic component built-in substrate according to the present invention.

[0053] The composite component 100 shown in Figure 4 comprises an electronic component built-in substrate 110, a mounted component 120 mounted on a component mounting surface 111 of the electronic component built-in substrate 110, and a motherboard 130 arranged on an external terminal surface 112 of the electronic component built-in substrate 110.

[0054] The motherboard 130 is electrically connected to the electronic component built-in substrate 110 via external terminals 140 provided on the external terminal surface 112 of the electronic component built-in substrate 110. The type of the external terminals 140 is not particularly limited, and examples thereof include solder balls.

[0055] As shown in FIG. 4, the mounting component 120 may be sealed with a molding resin 150 .

[0056] The electronic component built-in substrate 110 is, for example, the electronic component built-in substrate 1 shown in FIG.

[0057] For example, when the thermal expansion coefficient of the mounting component 120 is equal to or greater than the thermal expansion coefficient of the second region RG2 (see FIG. 1 ), the mounting component 120 is preferably mounted on the first surface 31 (see FIG. 1 ) of the insulating layer 30 constituting the electronic component built-in substrate 1 shown in FIG. 1 . In this case, the motherboard 130 is preferably electrically connected to the electronic component built-in substrate 1 via external terminals 140 provided on the second surface 32 (see FIG. 1 ) of the insulating layer 30. That is, when the thermal expansion coefficient of the mounting component 120 is equal to or greater than the thermal expansion coefficient of the second region RG2, it is preferable that the first surface 31 of the insulating layer 30 is the component mounting surface and the second surface 32 of the insulating layer 30 is the external terminal surface. The thermal expansion coefficient of the mounting component 120 may be greater than or equal to the thermal expansion coefficient of the second region RG2.

[0058] On the other hand, when the thermal expansion coefficient of the mounting component 120 is equal to or less than the thermal expansion coefficient of the first region RG1 (see FIG. 1 ), the mounting component 120 is preferably mounted on the second surface 32 (see FIG. 1 ) of the insulating layer 30 constituting the electronic component built-in substrate 1 shown in FIG. 1 . In this case, the motherboard 130 is preferably electrically connected to the electronic component built-in substrate 1 via external terminals 140 provided on the first surface 31 (see FIG. 1 ) of the insulating layer 30. That is, when the thermal expansion coefficient of the mounting component 120 is equal to or less than the thermal expansion coefficient of the first region RG1, it is preferable that the first surface 31 of the insulating layer 30 is the external terminal surface and the second surface 32 of the insulating layer 30 is the component mounting surface. The thermal expansion coefficient of the mounting component 120 may be smaller than or equal to the thermal expansion coefficient of the first region RG1.

[0059] Hereinafter, as an example of the electronic component 20 built into the cavity 15 of the core layer 10, a case where the electronic component 20 is a capacitor element will be described.

[0060] Fig. 5 is a cross-sectional view schematically showing an example of a capacitor element built into a cavity of a core layer constituting an electronic component built-in substrate of the present invention, and Fig. 6 is an enlarged cross-sectional view of a portion indicated by VI in the capacitor element shown in Fig. 5.

[0061] The capacitor element 200 shown in FIG. 5 includes, for example, a capacitor portion 300 .

[0062] The capacitor unit 300 includes an anode plate 310 serving as a first electrode, a dielectric layer 330 (see FIG. 6), and a cathode layer 320 serving as a second electrode.

[0063] The anode plate 310 includes a core portion 311 having a pair of main surfaces facing each other in the thickness direction (the vertical direction in FIG. 5 ), and a porous portion 312 provided on at least one of the main surfaces of the core portion 311. A dielectric layer 330 (see FIG. 6 ) is provided on the surface of the porous portion 312. The cathode layer 320 is provided on the surface of the dielectric layer 330. In this way, the capacitor portion 300 constitutes an electrolytic capacitor.

[0064] The cathode layer 320 includes, for example, a solid electrolyte layer 321 provided on the surface of the dielectric layer 330 (see FIG. 6). When the cathode layer 320 includes the solid electrolyte layer 321, the capacitor section 300 constitutes a solid electrolytic capacitor.

[0065] In FIG. 5, the solid electrolyte layer 321 is shown in a state where it is completely separated from the porous portion 312 of the anode plate 310. However, as shown in FIG. 6, it is preferable that a portion of the solid electrolyte layer 321 is provided inside the pores (recesses) of the dielectric layer 330.

[0066] The cathode layer 320 preferably further includes a conductor layer 322 provided on the surface of the solid electrolyte layer 321 .

[0067] The conductor layer 322 includes, for example, a first conductor layer 322A provided on the surface of the solid electrolyte layer 321 and a second conductor layer 322B provided on the surface of the first conductor layer 322A. In this way, the conductor layer 322 preferably includes multiple types of conductor layers.

[0068] As an example, the conductive layer 322 includes a carbon layer as the first conductive layer 322A and a copper layer as the second conductive layer 322B.

[0069] 5, the capacitor section 300 may further include an insulating mask layer 340 provided on the surface of the porous section 312. In this case, the insulating mask layer 340 is preferably provided in an area of ​​the surface of the porous section 312 where the cathode layer 320 is not formed.

[0070] The insulating mask layer 340 may be provided on the surface of the dielectric layer 330 on the porous portion 312. Furthermore, as shown in Fig. 6, the insulating mask layer 340 is preferably provided so as to fill the pores (recesses) of the porous portion 312 or the dielectric layer 330.

[0071] 5, the capacitor element 200 preferably further includes a sealing layer 350 provided to cover one or both sides of the capacitor portion 300 in the thickness direction. The sealing layer 350 protects the capacitor portion 300.

[0072] The sealing layer 350 may be composed of only one layer or two or more layers. When the sealing layer 350 is composed of two or more layers, the materials constituting the respective layers may be the same or different.

[0073] The sealing layer 350 is formed so as to seal the capacitor section 300 by, for example, a method of thermocompressing an insulating resin sheet, or a method of applying an insulating resin paste and then thermally curing it.

[0074] 5, a wiring layer 360 may be provided on at least one main surface of the capacitor element 200. In the example shown in Fig. 5, the wiring layer 360 is provided on both main surfaces of the sealing layer 350. The wiring layer 360 may include, for example, an anode wiring layer 361 electrically connected to the anode plate 310 and a cathode wiring layer 362 electrically connected to the cathode layer 320.

[0075] Capacitor element 200 may further include a through conductor 370 provided to penetrate capacitor section 300 in the thickness direction. By providing through conductor 370, the circuit connection distance between the front and back of capacitor element 200 as a whole can be shortened.

[0076] It is sufficient that the through conductor 370 is provided on at least the inner wall surface of the through hole that penetrates the capacitor section 300 in the thickness direction. That is, the through conductor 370 may be provided only on the inner wall surface of the through hole, or may be provided throughout the entire interior of the through hole.

[0077] When the through conductor 370 is provided on the inner wall surface of the through hole that penetrates the capacitor section 300 in the thickness direction, a resin-filled portion filled with a resin material may be provided inside the through conductor 370. The resin-filled portion may be a conductor or an insulator.

[0078] The through conductors 370 may include, for example, an anode through conductor 371 electrically connected to the anode plate 310 , and may include a cathode through conductor 372 electrically connected to the cathode layer 320 .

[0079] The anode through conductors 371 are electrically connected to the anode wiring layer 361. The anode wiring layer 361 is electrically connected to the anode plate 310 via the anode through conductors 371, for example.

[0080] It is preferable that an insulating material such as the sealing layer 350 is not filled between the anode through conductor 371 and the side wall surface of the anode plate 310 .

[0081] The anode through conductor 371 is preferably electrically connected to the side wall surface of the anode plate 310. Alternatively, the anode through conductor 371 may be electrically connected to the side wall surface of the anode plate 310 via the anode connection layer 380. In this case, the anode connection layer 380 functions as a barrier layer for the anode plate 310, more specifically, as a barrier layer for the core portion 311 and the porous portion 312.

[0082] The anode connecting layer 380 preferably includes a metal layer primarily made of nickel. For example, the anode connecting layer 380 including the metal layer primarily made of nickel can be formed by performing a zincate treatment on the wall surface of the anode plate 310 made of aluminum or an aluminum alloy, followed by electroless nickel plating. The anode connecting layer 380 may include, in order from the anode plate 310, a metal layer primarily made of zinc and a metal layer primarily made of nickel.

[0083] The cathode through conductor 372 is electrically connected to the cathode wiring layer 362. The cathode wiring layer 362 is electrically connected to the cathode layer 320 via a via conductor 365 that penetrates the sealing layer 350, for example.

[0084] It is preferable that an insulating material such as a sealing layer 350 be filled between the cathode through conductor 372 and the side wall surface of the anode plate 310 .

[0085] The electronic component-embedded substrate of the present invention is not limited to the above-described embodiment, and various applications and modifications can be made within the scope of the present invention with respect to the configurations of the core layer, electronic component, insulating layer, through conductor, conductor wiring layer, etc., and the manufacturing conditions of the electronic component-embedded substrate.

[0086] In the electronic component built-in substrate of the present invention, the electronic component is not limited to a capacitor element, but may be, for example, a passive element such as an inductor element.

[0087] In the electronic component built-in substrate of the present invention, when the electronic component is a capacitor element, the type of capacitor is not limited to an electrolytic capacitor such as a solid electrolytic capacitor, and may be, for example, a ceramic capacitor using barium titanate or the like, silicon nitride (SiN), silicon dioxide (SiO ２The capacitor may be a thin film capacitor using hydrogen fluoride (HF) or the like, or a trench capacitor having a metal-insulator-metal (MIM) structure. In any type of capacitor, it is preferable that the first electrode and the second electrode of opposite polarities face each other in the thickness direction of the electronic component-embedded substrate (the vertical direction in FIG. 1 ).

[0088] The detailed configuration of the capacitor element 200 will be described below.

[0089] One or more capacitor units 300 may be disposed inside sealing layer 350. When more than one capacitor unit 300 is disposed inside sealing layer 350, adjacent capacitor units 300 are preferably separated from each other by a through groove that penetrates capacitor unit 300 in the thickness direction. In this case, the through groove is preferably filled with an insulating material such as sealing layer 350.

[0090] When adjacent capacitor sections 300 are separated by a through groove, the adjacent capacitor sections 300 only need to be physically separated by the through groove. Therefore, the adjacent capacitor sections 300 may be electrically separated or electrically connected. The width of the through groove, i.e., the distance between adjacent capacitor sections 300, may be constant in the thickness direction or may decrease in the thickness direction.

[0091] When multiple capacitor units 300 are arranged inside the sealing layer 350, the multiple capacitor units 300 may be arranged side by side in a plane direction perpendicular to the thickness direction, may be arranged so as to be stacked in the thickness direction, or may be arranged in a combination of both. The multiple capacitor units 300 may be arranged regularly or irregularly. The size, shape, etc. of the capacitor units 300 may be the same, or some or all of them may be different. It is preferable that the configuration of each capacitor unit 300 is the same, but capacitor units 300 with different configurations may be included.

[0092] Examples of the planar shape of the capacitor section 300 when viewed from the thickness direction include a rectangle (square or oblong), a quadrangle other than a rectangle, a polygon such as a triangle, a pentagon, or a hexagon, a circle, an ellipse, a combination of these, etc. The planar shape of the capacitor section 300 may also be an L-shape, a C-shape, a stepped shape, etc.

[0093] The anode plate 310 is preferably made of a valve metal that exhibits so-called valve action. Examples of the valve metal include simple metals such as aluminum, tantalum, niobium, titanium, and zirconium, as well as alloys containing at least one of these metals. Among these, aluminum or an aluminum alloy is preferred.

[0094] The shape of the anode plate 310 is preferably a flat plate, and more preferably a foil. Thus, in this specification, the term "plate-like" includes "foil-like".

[0095] The anode plate 310 may have the porous portion 312 on only one main surface of the core portion 311, or may have the porous portion 312 on both main surfaces of the core portion 311. The porous portion 312 is preferably a porous layer formed on the surface of the core portion 311, and more preferably an etched layer.

[0096] The thickness of the anode plate 310 before etching is preferably 60 μm or more and 200 μm or less. The thickness of the unetched core portion 311 after etching is preferably 15 μm or more and 70 μm or less. The thickness of the porous portion 312 is designed according to the required withstand voltage and electrostatic capacitance, but the combined thickness of the porous portions 312 on both sides of the core portion 311 is preferably 10 μm or more and 180 μm or less.

[0097] The pore diameter of the porous portion 312 is preferably 10 nm or more and 600 nm or less. The pore diameter of the porous portion 312 refers to the median diameter D50 measured with a mercury porosimeter. The pore diameter of the porous portion 312 can be controlled by adjusting various etching conditions, for example.

[0098] The dielectric layer 330 provided on the surface of the porous portion 312 is porous, reflecting the surface condition of the porous portion 312, and has a finely uneven surface shape. The dielectric layer 330 is preferably made of an oxide film of the valve metal. For example, when aluminum foil is used as the anode plate 310, the dielectric layer 330 made of an oxide film can be formed by anodizing the surface of the aluminum foil in an aqueous solution containing ammonium adipate or the like (also called chemical conversion treatment).

[0099] The thickness of the dielectric layer 330 is designed according to the required withstand voltage and capacitance, but is preferably 10 nm or more and 100 nm or less.

[0100] When the cathode layer 320 includes a solid electrolyte layer 321, examples of materials constituting the solid electrolyte layer 321 include conductive polymers such as polypyrroles, polythiophenes, and polyanilines. Among these, polythiophenes are preferred, and poly(3,4-ethylenedioxythiophene), also known as PEDOT, is particularly preferred. The conductive polymer may also contain a dopant such as polystyrene sulfonate (PSS). The solid electrolyte layer 321 preferably includes an inner layer that fills the pores (recesses) of the dielectric layer 330 and an outer layer that covers the dielectric layer 330.

[0101] The thickness of solid electrolyte layer 321 from the surface of porous portion 312 is preferably 2 μm or more and 20 μm or less.

[0102] The solid electrolyte layer 321 is formed, for example, by a method of forming a polymer film of poly(3,4-ethylenedioxythiophene) or the like on the surface of the dielectric layer 330 using a treatment liquid containing a monomer such as 3,4-ethylenedioxythiophene, or by a method of applying a dispersion of a polymer such as poly(3,4-ethylenedioxythiophene) to the surface of the dielectric layer 330 and drying it.

[0103] The solid electrolyte layer 321 can be formed in a predetermined region by applying the above-mentioned treatment liquid or dispersion liquid to the surface of the dielectric layer 330 by a method such as sponge transfer, screen printing, dispenser application, or inkjet printing.

[0104] When the cathode layer 320 includes the conductor layer 322, the conductor layer 322 includes at least one layer selected from a conductive resin layer and a metal layer. The conductor layer 322 may be composed of only a conductive resin layer or only a metal layer. The conductor layer 322 preferably covers the entire surface of the solid electrolyte layer 321.

[0105] The conductive resin layer may be, for example, a conductive adhesive layer containing at least one conductive filler selected from the group consisting of silver filler, copper filler, nickel filler, and carbon filler.

[0106] Examples of the metal layer include a metal plating film and a metal foil. The metal layer is preferably made of at least one metal selected from the group consisting of nickel, copper, silver, and alloys containing these metals as the main component. The term "main component" refers to the elemental component with the largest weight ratio.

[0107] The conductor layer 322 includes, for example, a carbon layer provided on the surface of the solid electrolyte layer 321 and a copper layer provided on the surface of the carbon layer.

[0108] The carbon layer is provided to electrically and mechanically connect the solid electrolyte layer 321 and the copper layer. The carbon layer can be formed in a predetermined region by applying a carbon paste to the surface of the solid electrolyte layer 321 by sponge transfer, screen printing, dispenser application, inkjet printing, or other methods. The thickness of the carbon layer is preferably 2 μm or more and 20 μm or less.

[0109] The copper layer can be formed in a predetermined region by applying a copper paste to the surface of the carbon layer by sponge transfer, screen printing, spray coating, dispenser coating, inkjet printing, etc. The thickness of the copper layer is preferably 2 μm or more and 20 μm or less.

[0110] The insulating mask layer 340 is made of an insulating material, and in this case, the insulating mask layer 340 preferably contains an insulating resin.

[0111] Examples of insulating resins contained in the insulating mask layer 340 include polyphenylsulfone resin, polyethersulfone resin, cyanate ester resin, fluororesin (tetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, etc.), polyimide resin, polyamideimide resin, epoxy resin, and derivatives or precursors thereof.

[0112] The insulating mask layer 340 may be made of the same resin as the sealing layer 350. Unlike the sealing layer 350, if the insulating mask layer 340 contains an inorganic filler, it may adversely affect the effective capacitance portion of the capacitor section 300. Therefore, it is preferable that the insulating mask layer 340 be made of a resin alone.

[0113] The insulating mask layer 340 can be formed in a predetermined area by applying a mask material, such as a composition containing an insulating resin, to the surface of the porous portion 312 by a method such as sponge transfer, screen printing, dispenser application, or inkjet printing.

[0114] The insulating mask layer 340 may be formed on the porous portion 312 either before or after the dielectric layer 330 is formed.

[0115] The sealing layer 350 is made of an insulating material. In this case, the sealing layer 350 preferably contains an insulating resin.

[0116] Examples of the insulating resin contained in the sealing layer 350 include epoxy resin and phenol resin.

[0117] Preferably, the sealing layer 350 further contains a filler such as an inorganic filler.

[0118] Examples of the inorganic filler contained in the sealing layer 350 include silica particles and alumina particles.

[0119] Between the capacitor section 300 and the sealing layer 350, for example, a layer such as a stress relaxation layer or a moisture-proof film may be provided.

[0120] The present specification discloses the following:

[0121] an insulating layer provided so as to cover the core layer and the electronic component from both sides in the thickness direction and having a first surface and a second surface opposed to each other in the thickness direction; a through conductor provided so as to penetrate the core layer in the thickness direction; and a conductor wiring layer provided on a part of at least one of the first surface and the second surface of the insulating layer, wherein the first surface of the insulating layer is a component mounting surface and the second surface of the insulating layer is an external terminal surface, or the first surface of the insulating layer is the external terminal surface and the second surface of the insulating layer is the component mounting surface, and wherein a region from a central surface between the first surface and the second surface in the thickness direction to an outermost surface on the first surface side is defined as a first region, and a region from the central surface to the outermost surface on the second surface side is defined as a second region, and wherein the thermal expansion coefficient of the second region is greater than that of the first region.

[0122] <2> The electronic component-embedded substrate according to <1>, wherein the thickness of the insulating layer on the first surface side is greater than the thickness of the insulating layer on the second surface side.

[0123] <3> The electronic component-embedded substrate according to <1> or <2>, wherein the electronic component is disposed closer to the second surface of the insulating layer than to the first surface of the insulating layer in the thickness direction.

[0124] <4> The electronic component-embedded substrate according to <2> or <3>, wherein the coefficient of thermal expansion of the electronic component is larger than the coefficient of thermal expansion of the insulating layer.

[0125] <5> The electronic component-embedded substrate according to any one of <1> to <4>, wherein a total area of ​​the conductor wiring layers provided on the second surface of the insulating layer is larger than a total area of ​​the conductor wiring layers provided on the first surface of the insulating layer.

[0126] <6> A composite component comprising: the electronic component-embedded substrate according to any one of <1> to <5>; and a mounting component mounted on the first surface of the insulating layer, wherein the mounting component has a thermal expansion coefficient equal to or greater than the thermal expansion coefficient of the second region.

[0127] <7> The composite component according to <6>, further comprising a motherboard electrically connected to the electronic component-embedded substrate via external terminals provided on the second surface of the insulating layer.

[0128] <8> A composite component comprising: the electronic component-embedded substrate according to any one of <1> to <5>; and a mounting component mounted on the second surface of the insulating layer, wherein the mounting component has a thermal expansion coefficient equal to or lower than the thermal expansion coefficient of the first region.

[0129] <9> The composite component according to <8>, further comprising a motherboard electrically connected to the electronic component-embedded substrate via external terminals provided on the first surface of the insulating layer.

[0130] REFERENCE SIGNS LIST 1, 1a Electronic component built-in substrate 2 Mounted component 3 Mother substrate 10 Core layer 15 Cavity 20 Electronic component 25 Insulating member 30 Insulating layer 31 First surface 32 Second surface 35 Central surface 40 Through conductor 50 Conductor wiring layer 55 Via conductor 60 Wiring layer 100 Composite component 110 Electronic component built-in substrate 111 Component mounting surface 112 External terminal surface 120 Mounted component 130 Mother substrate 140 External terminal 150 Molding resin 200 Capacitor element (electronic component) 300 Capacitor section 310 Anode plate 311 Core section 312 Porous section 320 Cathode layer 321 Solid electrolyte layer 322 Conductor layer 322A First conductive layer 322B Second conductive layer 330 Dielectric layer 340 insulating mask layer 350 sealing layer 360 wiring layer 361 anode wiring layer 362 cathode wiring layer 365 via conductor 370 through conductor 371 anode through conductor 372 cathode through conductor 380 anode connection layer RG1 first region RG2 second region

Claims

1. An electronic component embedded substrate comprising: a core layer having a cavity penetrating therethrough in the thickness direction; an electronic component embedded in the cavity of the core layer; an insulating layer provided so as to cover the core layer and the electronic component from both sides in the thickness direction and having a first surface and a second surface opposing each other in the thickness direction; a through conductor provided so as to penetrate the core layer in the thickness direction; and a conductor wiring layer provided on a portion of at least one of the first and second surfaces of the insulating layer, wherein the first surface of the insulating layer is a component mounting surface and the second surface of the insulating layer is an external terminal surface, or the first surface of the insulating layer is the external terminal surface and the second surface of the insulating layer is the component mounting surface, and wherein a first region is defined as a region from a central plane between the first and second surfaces in the thickness direction to the outermost surface on the first surface side, and a second region is defined as a region from the central plane to the outermost surface on the second surface side, and the second region has a thermal expansion coefficient greater than that of the first region.

2. The electronic component built-in substrate according to claim 1, wherein the thickness of the insulating layer on the first surface side is greater than the thickness of the insulating layer on the second surface side.

3. The electronic component-embedded substrate according to claim 1 or 2, wherein the electronic component is disposed closer to the second surface of the insulating layer than to the first surface of the insulating layer in the thickness direction.

4. The electronic component-embedded substrate according to claim 2 or 3, wherein the coefficient of thermal expansion of the electronic component is greater than the coefficient of thermal expansion of the insulating layer.

5. An electronic component-embedded substrate according to any one of claims 1 to 4, wherein the total area of ​​the conductor wiring layers provided on the second surface of the insulating layer is larger than the total area of ​​the conductor wiring layers provided on the first surface of the insulating layer.

6. A composite component comprising: the electronic component built-in substrate according to any one of claims 1 to 5; and a mounted component mounted on the first surface of the insulating layer, wherein the thermal expansion coefficient of the mounted component is equal to or greater than the thermal expansion coefficient of the second region.

7. The composite part according to claim 6, further comprising a motherboard electrically connected to said electronic component-embedded substrate via external terminals provided on said second surface of said insulating layer.

8. A composite component comprising: the substrate with built-in electronic components according to any one of claims 1 to 5; and a mounted component mounted on the second surface of the insulating layer, wherein the thermal expansion coefficient of the mounted component is equal to or less than the thermal expansion coefficient of the first region.

9. The composite part according to claim 8, further comprising a motherboard electrically connected to said electronic component-embedded substrate via external terminals provided on said first surface of said insulating layer.

Images