Manufacturing method of substrate with built-in electronic components and substrate with built-in electronic components

Abstract

A method for manufacturing a substrate with built-in electronic components is provided, which does not require the formation of protrusions for partitioning electronic components within a space portion that accommodates a plurality of electronic components in a cavity of a core substrate. [Solution] A method for manufacturing a substrate with embedded electronic components includes preparing a core substrate (101), forming a cavity (102) in the core substrate (101) for accommodating an electronic component assembly (103) composed of a plurality of electronic components (131) and a molded resin (132) that entirely covers the electronic components (131), placing an adhesive tape (105) on the underside of the core substrate (101), temporarily fixing the electronic component assembly (103) on the adhesive tape (105) in the cavity (102), filling a resin filler material inside the cavity (102) with the electronic component assembly (103) temporarily fixed, then hardening the resin filler material, and removing the adhesive tape (105), wherein the molded resin (132) has a slope that slopes from top to bottom.

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing an electronic component-embedded substrate and an electronic component-embedded substrate, and more particularly to a method for manufacturing an electronic component-embedded substrate and an electronic component-embedded substrate having a plurality of built-in electronic components. [Background technology]

[0002] When multiple electronic components such as chip capacitors are accommodated in a single opening of a printed wiring board, if the positioning accuracy of the electronic components within the opening is low, the electronic components may not be connected to the via conductors. Therefore, a printed wiring board with low positioning accuracy of the electronic components within the opening has low connection reliability. From this perspective, a printed wiring board has been proposed that improves connection reliability by improving the positioning accuracy of the electronic components within the opening (Patent Document 1).

[0003] Fig. 3 is a plan view showing an example of an embodiment of such a printed wiring board. As shown in Fig. 3, a first cavity 26A of a core substrate of the printed wiring board includes rectangular spaces 26c and 26d for accommodating electronic components, and rectangular first protrusions 28a for separating the electronic components within the spaces. The first protrusions 28a protrude from sidewalls 26AW of the first cavity in directions parallel to the first and second surfaces of the core substrate, and a pair of first protrusions 28a are formed to face each other. A communication portion 26e connecting space 26c and space 26d is formed between the first protrusion 28a and the opposing first protrusion 28a.

[0004] First cavity 26A is formed with spaces 26c and 26d, each accommodating N electronic components in one direction, and N-1 protrusions 28a that separate the electronic components. In first cavity 26A, cavity width A1 in one direction, electronic component width B, and protrusion tip width C1 are set to satisfy a predetermined relationship. In the core substrate of the printed wiring board, each first cavity 26A accommodates two electronic components, which reduces dead space for wiring compared to when two adjacent cavities each accommodating one electronic component are used, making it easier to route the wiring. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2015-220283 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the technology disclosed in Patent Document 1 requires the formation of rectangular spaces 26c and 26d in the first cavity 26A of the core substrate for accommodating electronic components, as well as rectangular first protrusions 28a for separating the electronic components within the spaces. Therefore, the technology disclosed in Patent Document 1 requires a complex manufacturing process for forming the first cavity 26A for accommodating multiple electronic components. Furthermore, the technology disclosed in Patent Document 1 has size limitations, since when accommodating multiple electronic components of different sizes in the first cavity 26A, the first cavity 26A must be formed taking into account the sizes of the electronic components. Furthermore, the technology disclosed in Patent Document 1 has the problem that if the gap formed between the first cavity 26A of the core substrate and the electronic component is narrow, the gap cannot be sufficiently filled with filling resin. [Means for solving the problem]

[0007] The method for manufacturing an electronic component-embedded substrate of the present invention is a method for manufacturing an electronic component-embedded substrate in which multiple electronic components are embedded in a cavity of a core substrate via a resin filler, and includes the steps of preparing a core substrate, forming the cavity in the core substrate for accommodating an electronic component assembly consisting of multiple electronic components and a molded resin that covers the entire electronic components, placing an adhesive tape on the underside of the core substrate, temporarily fixing the electronic component assembly on the adhesive tape in the cavity, filling the cavity in which the electronic component assembly is temporarily fixed with the resin filler and then hardening the resin filler, and removing the adhesive tape, wherein the molded resin has a slope that slopes from above to below. In addition, the electronic component embedded substrate of the present invention is an electronic component embedded substrate having a plurality of electronic components built in, and comprises a core substrate, a cavity formed inside the core substrate, an electronic component assembly housed in the cavity, and a resin filler that covers the core substrate and the electronic component assembly, wherein the electronic component assembly is composed of the electronic components and a molded resin that covers the entire electronic components, and the molded resin has a slope that slopes from top to bottom. [Brief explanation of the drawings]

[0008] [Figure 1A] 1 is a top view for explaining an embodiment of an electronic component built-in substrate according to the present invention; [Figure 1B] 1 is a cross-sectional view illustrating an embodiment of a substrate with built-in electronic components according to the present invention. [Figure 2A] 1A to 1C are cross-sectional views illustrating an embodiment of a method for manufacturing an electronic component-embedded substrate according to the present invention. [Figure 2B] 1A to 1C are cross-sectional views illustrating an embodiment of a method for manufacturing an electronic component-embedded substrate according to the present invention. [Figure 2C] 1A to 1C are cross-sectional views illustrating an embodiment of a method for manufacturing an electronic component-embedded substrate according to the present invention. [Figure 2D]1A to 1C are cross-sectional views illustrating an embodiment of a method for manufacturing an electronic component-embedded substrate according to the present invention. [Figure 2E] 1A to 1C are cross-sectional views illustrating an embodiment of a method for manufacturing an electronic component-embedded substrate according to the present invention. [Figure 2F] 1A to 1C are cross-sectional views illustrating an embodiment of a method for manufacturing an electronic component-embedded substrate according to the present invention. [Figure 2G] 1A to 1C are cross-sectional views illustrating an embodiment of a method for manufacturing an electronic component-embedded substrate according to the present invention. [Figure 2H] 1A to 1C are cross-sectional views illustrating an embodiment of a method for manufacturing an electronic component-embedded substrate according to the present invention. [Figure 2I] 1A to 1C are cross-sectional views illustrating an embodiment of a method for manufacturing an electronic component-embedded substrate according to the present invention. [Figure 2J] 1A to 1C are cross-sectional views illustrating an embodiment of a method for manufacturing an electronic component-embedded substrate according to the present invention. [Figure 2K] 1A to 1C are cross-sectional views illustrating an embodiment of a method for manufacturing an electronic component-embedded substrate according to the present invention. [Figure 3] FIG. 1 is a plan view of a cavity in a core substrate of a conventional printed wiring board. DETAILED DESCRIPTION OF THE INVENTION

[0009] <About electronic component embedded substrates> An embodiment of a manufacturing method for a substrate with built-in electronic components and a substrate with built-in electronic components according to the present invention will be described with reference to the drawings. In the example shown in Figures 1 and 2, the dimensions of each member, particularly the height dimension, are shown as different from the actual dimensions in order to better understand the features of the present invention.

[0010] 1A is a top view illustrating one embodiment of an electronic component built-in substrate according to the present invention. As shown in FIG. 1A, electronic component built-in substrate 100 includes core substrate 101, cavity 102 formed inside core substrate 101, electronic component assembly 103 housed in cavity 102, and resin filler 104 covering core substrate 101 and electronic component assembly 103.

[0011] Core substrate 101 may be a copper-clad laminate having copper foil seed layers formed on both sides of the substrate. Commercially available copper-clad laminates can be used. Core substrate 101 may also be a multilayer core substrate having multiple resin insulating layers and multiple conductor layers alternately stacked.

[0012] Cavity 102 is formed inside core substrate 101 to accommodate electronic component assembly 103. Electronic component assembly 103 is composed of a plurality of electronic components 131 and molded resin 132. Cavity 102 may have any shape that can accommodate electronic component assembly 103, and is not particularly limited. Cavity 102 may have a simple shape, for example, a rectangular shape in a plan view. That is, cavity 102 may have a simplified shape in terms of the manufacturing process of electronic component-embedded substrate 100.

[0013] In other words, even when multiple electronic components are housed inside cavity 102, it is not necessary to provide a protrusion for separating one electronic component from another. Furthermore, it is not necessary to provide a communication portion for connecting the space housing one electronic component with the space housing another electronic component. Thus, even when multiple electronic components are housed inside cavity 102 formed in core substrate 101, electronic component-embedded substrate 100 can house these electronic components without making the shape of cavity 102 complex.

[0014] 1B is a cross-sectional view illustrating one embodiment of an electronic component-embedded substrate manufactured by the manufacturing method for an electronic component-embedded substrate according to the present invention. As shown in FIG. 1B, electronic component assembly 103 is composed of a plurality of electronic components 131 and mold resin 132 that entirely covers the plurality of electronic components 131. Here, electronic components 131 that make up electronic component assembly 103 may be electronic components such as multilayer ceramic chip capacitors, chip resistors, inductors, thermistors, etc.

[0015] The number of electronic components 131 can be set appropriately depending on the performance of electronic component built-in substrate 100 to be manufactured, and may be 2 to 10. In this way, by employing electronic component assembly 103, electronic component built-in substrate 100 can incorporate multiple electronic components 131 inside cavity 102 formed in core substrate 101.

[0016] Here, the multiple electronic components 131 may have the same thickness (height) or different thicknesses (heights). The multiple electronic components 131 may have the same length or different lengths. Furthermore, the multiple electronic components 131 may have the same width or different widths.

[0017] That is, electronic component built-in substrate 100 employs electronic component assembly 103 including multiple electronic components 131 in order to build multiple electronic components 131 into core substrate 101, without handling each electronic component 131 separately and independently. Therefore, electronic component built-in substrate 100 can build multiple electronic components 131 of different sizes into cavity 102 of electronic component built-in substrate 100 with good positioning accuracy, without being subject to structural limitations such as size and shape derived from the shape of each electronic component 131.

[0018] Molding resin 132 constituting electronic component assembly 103 may be formed from a resin composition containing a thermosetting epoxy resin and silica (SiO2, silicon dioxide) particles mixed in. Molding resin 132 can be formed by heating and softening a pellet-shaped resin composition in a plunger, forcing the molten resin composition into a mold, and then cooling and solidifying it.

[0019] Here, molded resin 132 has a slope that slopes downward. That is, molded resin 132 is formed so that its wall surface slopes downward inside cavity 102. Because molded resin 132 has a slope that slopes downward, even if the gap formed between the side wall of cavity 102 and electronic component assembly 103 is small, molten resin filler 104 can be filled into the gap without shortage.

[0020] Substrate 100 with built-in electronic components includes resin filler 104 that covers core substrate 101 and electronic component assembly 103. That is, substrate 100 with built-in electronic components includes resin filler 104 that fills the entire surface of core substrate 101 and gaps formed between core substrate 101 and electronic component assembly 103. Resin filler 104 may be a resin composition containing an inorganic filler such as silica or alumina and an epoxy resin, and specifically may be an electrically insulating material obtained by impregnating glass cloth with a thermosetting resin such as an epoxy resin or a bismaleimide triazine resin.

[0021] Electronic component-embedded substrate 100 having such a structure is used as a core substrate that constitutes a multilayer printed wiring board, and a build-up layer (not shown) can be formed on the upper surface of the core substrate. As described above, even if the gap formed between the side wall of cavity 102 and electronic component assembly 103 is small, electronic component-embedded substrate 100 has molten resin filler 104 filled in the gap without insufficiency. This makes it possible to reduce the size of a printed wiring board that includes electronic component-embedded substrate 100 in which multiple electronic components are precisely positioned.

[0022] <Method of manufacturing a substrate with built-in electronic components according to the present invention> 2A to 2K are diagrams illustrating an embodiment of a method for manufacturing an electronic component built-in substrate according to the present invention. Hereinafter, an embodiment of a method for manufacturing an electronic component built-in substrate according to the present invention will be described in order using FIGS. 2A to 2K.

[0023] First, as shown in Fig. 2A, a core substrate 101 is prepared. The core substrate 101 may be, for example, a copper-clad laminate having copper foil seed layers formed on both sides of a substrate, and a commercially available copper-clad laminate may be prepared.

[0024] 2B, a cavity 102 for accommodating electronic component assembly 103 is formed in core substrate 101. Cavity 102 can be formed by positioning the location where cavity 102 is to be formed in advance, and then easily processing core substrate 101 with a laser or the like so as to penetrate the core substrate 101. Forming cavity 102 does not require the provision of a protrusion for separating one electronic component from another electronic component, and cavity 102 does not require the provision of a communication portion for connecting the space housing one electronic component with the space housing another electronic component. Therefore, the method for manufacturing an electronic component built-in substrate according to the present invention makes it possible to easily form cavity 102 for accommodating electronic component assembly 103 in core substrate 101.

[0025] 2C, adhesive tape 105 is placed on the lower surface of core substrate 101. Adhesive tape 105 is placed so that the upper surface, which will be the adhesive side of adhesive tape 105, comes into contact with the lower surface of core substrate 101.

[0026] 2D , electronic component assembly 103 is temporarily fixed on adhesive tape 105 exposed from inside cavity 102. Electronic component assembly 103 is temporarily fixed so that electronic component assembly 103 is housed inside cavity 102. The width of the bottom surface of electronic component assembly 103 is designed to be slightly smaller than the width of the bottom surface of cavity 102. This makes it extremely easy to temporarily fix electronic component assembly 103 on adhesive tape 105 exposed from inside cavity 102.

[0027] Electronic component assembly 103 is composed of a plurality of electronic components 131 and molded resin 132 that entirely covers the plurality of electronic components 131. The plurality of electronic components 131 have already been precisely positioned inside electronic component assembly 103 by being fixed by molded resin 132. Therefore, the manufacturing method of the electronic component-embedded substrate according to the present invention makes it possible to embed multiple electronic components 131 in a single cavity 102 having a simple shape with great ease and with high precision, without the individual electronic components 131 included in the multiple electronic components 131 interfering with each other.

[0028] Moreover, the method for manufacturing an electronic component-embedded substrate according to the present invention does not involve placing each of electronic components 131 that make up multiple electronic components 131 directly inside cavity 102. Therefore, even if there is a large difference in thickness between core substrate 101 having cavity 102 and the thickness of electronic component 131, the method for manufacturing an electronic component-embedded substrate according to the present invention can very easily embed electronic component 131 inside cavity 102 in a state where the electronic component is positioned with high precision.

[0029] Here, electronic component assembly 103 may be manufactured by, for example, employing the following manufacturing process I. Specifically, as shown in FIG. 2E, carrier 106 is prepared for forming electronic component assembly 103, which is composed of a plurality of electronic components 131 and molded resin 132. Carrier 106 preferably has a lower surface that is slightly larger than the lower surface of electronic component assembly 103. Carrier 106 preferably has a thickness of 1 to 20 μm, and more preferably less than 10 μm. The material constituting carrier 106 is preferably a polyester-based material, such as polyethylene terephthalate (PET) or polybutylene terephthalate (PBT).

[0030] Next, as shown in FIG. 2F, a plurality of electronic components 131 are placed on the upper surface of the carrier 106. The plurality of electronic components 103 may have the same thickness (height) or different thicknesses (heights). The plurality of electronic components 103 may have the same length or different lengths. Furthermore, the plurality of electronic components 103 may have the same width or different widths. The order in which the plurality of different electronic components 131 are arranged can be set as appropriate. The intervals formed between adjacent electronic components 131 can be set as appropriate.

[0031] Next, as shown in Fig. 2G(a), molten molding resin 134 is poured from above the plurality of electronic components 103 using plunger 133 so as to cover the plurality of electronic components 103. Furthermore, as shown in Fig. 2H(a), molten molding resin 134 poured so as to cover the plurality of electronic components 103 is cooled and solidified. By solidifying the molten molding resin 134, the molten molding resin 134 becomes solidified molding resin 135.

[0032] Next, as shown in FIG. 2I, solidified molding resin 135 obtained by cooling molten molding resin 134 is shaped by cutting, grinding, etc. Solidified molded resin 135 is shaped by cutting, grinding, etc. so that molded molded resin 132 forms sloped surface 136 that slopes downward. Solidified molded resin 135 may be shaped so that multiple electronic components 131 having a predetermined thickness are housed inside cavity 102. After solidified molding resin 135 is shaped by cutting, grinding, etc., carrier 106 is peeled off from solidified molding resin 132, thereby manufacturing electronic component assembly 103 on which molding resin 132 is formed.

[0033] From another perspective, electronic component assembly 103 may be manufactured, for example, by employing the following manufacturing process II. As described above, as shown in FIG. 2E, carrier 106 is prepared for forming electronic component assembly 103, which is composed of multiple electronic components 131 and mold resin 132. Next, as shown in FIG. 2F, multiple electronic components 131 are placed on the upper surface of carrier 106.

[0034] Next, as shown in FIG. 2G(b), a mold resin molding die 107 is prepared for forming a slope 136 sloping from above to below in the mold resin 132. The mold resin molding die 107 is placed on the carrier 106 so as to surround the electronic component 131. The mold resin molding die 107 has a slope for forming a slope 136 sloping from above to below in the mold resin 132 that constitutes the electronic component assembly 103.

[0035] 2H(b), molten molded resin 134 is poured from above electronic component 103 into mold gap 108 formed by adhesive tape 105 and molded resin molding die 107. Then, by cooling molten molded resin 134 poured into molded resin molding die 107, molded resin 132 having slope 136 sloping downward can be formed.

[0036] 2I, mold resin forming die 107 is removed from formed mold resin 132. Thereafter, carrier 106 is peeled off from mold resin 132 and multiple electronic components 103 that constitute electronic component assembly 103. By peeling carrier 106 off electronic component assembly 103 in this manner, electronic component assembly 103 can be manufactured.

[0037] In this way, in the manufacturing method of the electronic component-embedded substrate according to the present invention, electronic component assembly 103 can be obtained, for example, by going through manufacturing process I or manufacturing process II, in which constituent molded resin 132 has a slope that slopes from top to bottom.

[0038] Next, as shown in Fig. 2J, resin filler 104 is placed on core substrate 101, and then resin filler 104 is heated and pressurized. Furthermore, as shown in Fig. 2K, resin filler 104 is heated and pressurized, whereby molten resin filler 104 fills the interior of cavity 102 and the surface of core substrate 101. Cavity interior gap 141 formed by cavity 102 accommodating electronic component assembly 103 composed of multiple electronic components 103 and molded resin 132 disappears as molten resin filler 104 fills the interior of cavity 102.

[0039] 2K, molten resin filler 104 is cooled and hardened. Thereafter, adhesive tape 105 is peeled and removed from the lower surface of core substrate 101, the lower surface of solidified resin filler 104, and the lower surface of electronic component assembly 103, thereby obtaining electronic component built-in substrate 100.

[0040] If necessary, a build-up layer can be formed on the manufactured electronic component built-in substrate 100 using the electronic component built-in substrate 100 as a core substrate. In each step, conventionally known processing methods and materials can be used.

[0041] Thus, according to the manufacturing method of the electronic component-embedded substrate of the present invention, there is no need to form protrusions to separate the electronic components within the space in order to accommodate the electronic components in the cavity of the core substrate, and it is possible to manufacture an electronic component-embedded substrate in which multiple electronic components are precisely positioned by simply forming an extremely simple cavity. Furthermore, according to the method for manufacturing a substrate with built-in electronic components of the present invention, even when a plurality of electronic components of different sizes are accommodated in a cavity, it is possible to manufacture a substrate with built-in electronic components of small size without having to consider the size constraints that would require the cavity to be formed taking into account the size of each electronic component.

[0042] Furthermore, according to the manufacturing method of the component-embedded substrate of the present invention, the slope of the electronic component assembly is inclined from top to bottom, so that even if the gap formed between the cavity of the core substrate and the electronic component is narrow, the gap can be sufficiently filled with resin filler. [Explanation of symbols]

[0043] 100 Electronic component embedded board 101 Core substrate 102 Cavity 103 Electronic component assembly 104 Resin filler 131 Electronic Components 132 Molding resin 133 Plunger 134 Molten Molding Resin 135 Solidified molding resin 136 Slope 104 Resin filler 141 Cavity internal clearance 105 adhesive tape 106 Career 107 Mold resin molding die 108 Mold gap

Claims

1. A method for manufacturing an electronic component-embedded substrate in which a plurality of electronic components are embedded in a cavity of a core substrate via a resin filler, comprising: Providing a core substrate; forming the cavity in the core substrate for accommodating an electronic component assembly composed of a plurality of the electronic components and a molding resin that entirely covers the electronic components; Placing an adhesive tape on the lower surface of the core substrate; temporarily fixing the electronic component assembly on the adhesive tape in the cavity; filling the cavity in which the electronic component assembly is temporarily fixed with the resin filler and then curing the resin filler; removing the adhesive tape; The molding resin has a slope that slopes downward.

2. The method for manufacturing a substrate with built-in electronic components according to claim 1 , wherein the electronic components have different thicknesses.

3. The method for manufacturing a substrate with built-in electronic components according to claim 1 , wherein a copper-clad laminate is used as the core substrate.

4. An electronic component built-in substrate having a plurality of built-in electronic components, A core substrate; a cavity formed inside the core substrate; an electronic component assembly accommodated in the cavity; a resin filler that covers the core substrate and the electronic component assembly, The electronic component assembly is composed of the electronic components and a molding resin that covers the entire electronic components, and the molding resin has a slope that slopes downward.

5. The electronic component-embedded substrate according to claim 4 , wherein the electronic components have different thicknesses.

6. 5. The electronic component-embedded substrate according to claim 4, wherein the core substrate is a copper-clad laminate.

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