Substrate and electronic component module

Abstract

Provided are a substrate and an electronic component module in which conductivity and substrate strength are further improved. The substrate 1 according to the present disclosure comprises: a plate material 10; copper electrodes 12 that are provided on the front surface and / or the back surface of the plate material 10; an internal conductor 11 that is provided inside the plate material 10 and extends from the inside of the plate material 10 to the front surface and the back surface; and first metals 21 that are separated from the copper electrodes 12 and are arranged at positions aligned in a direction intersecting the thickness direction of the plate material 10. The internal conductor 11 is electrically connected to the copper electrodes 12, and the Young's modulus of the first metals 21 is higher than that of the copper electrodes 12.

Description

Substrate and Electronic Component Module

[0001] The present disclosure relates to a substrate and an electronic component module.

[0002] Patent Document 1 discloses a printed wiring board for an IC card, characterized in that a conductor circuit pattern is formed from a metal foil that has higher bending rigidity and higher corrosion resistance than copper, such as austenitic stainless steel foil or precipitation hardening stainless steel foil.

[0003] More specifically, as shown in FIG. 2 of Patent Document 1, after forming a through hole (4) in a resin base material (1), a stainless steel foil (6) is bonded to the external connection terminal surface of the resin base material (1). In order to establish conduction with the stainless steel foil (6), a conductive paste (13) is printed in the through hole (4), and a printed wiring board for an IC card provided with nickel-gold plating (10) is disclosed.

[0004] Japanese Unexamined Patent Publication No. Hei 1-119091

[0005] In the printed wiring board for an IC card described in Patent Document 1, the conductor circuit pattern is formed of austenitic stainless steel foil or precipitation hardening stainless steel foil that is less likely to bend than copper foil, thereby making the entire printed wiring board for an IC card less likely to bend, and aims to prevent the occurrence of semiconductor cracks and the breakage of fine wires. Therefore, when the technology of the printed wiring board for an IC card described in Patent Document 1 is applied to an electronic component module on which electronic components are mounted, there is room for improvement in the conductivity between the electronic components and the wiring board. Specifically, although the printed wiring board for an IC card described in Patent Document 1 uses stainless steel foil for wiring to increase substrate strength, the wiring resistance is increased.

[0006] In view of this perspective, an object of the present disclosure is to provide a substrate and an electronic component module with further improved conductivity and substrate strength.

[0007] The substrate of this disclosure comprises: a plate material; copper electrodes provided on the surface and / or back surface of the plate material; an internal conductor provided inside the plate material and extending from the inside to the surface and back surface of the plate material; and a first metal positioned spaced apart from the copper electrodes and aligned in a direction intersecting the thickness direction of the plate material, wherein the internal conductor is electrically connected to the copper electrodes, and the Young's modulus of the first metal is higher than that of the copper electrodes.

[0008] Furthermore, the electronic component module of this disclosure comprises the aforementioned substrate and electronic components mounted on the substrate.

[0009] According to the substrate and electronic component module of this disclosure, copper electrodes with better conductivity than stainless steel are used, and furthermore, a first metal with a higher Young's modulus than the copper electrodes is positioned at a distance from the copper electrodes and aligned in a direction intersecting the thickness direction of the plate material, thereby further improving conductivity and substrate strength.

[0010] Figure 1 is a schematic cross-sectional view illustrating the manufacturing process of the substrate according to the first embodiment. Figure 2 is a schematic cross-sectional view illustrating the manufacturing process of the substrate according to the first embodiment. Figure 3 is a schematic cross-sectional view illustrating the manufacturing process of the substrate according to the first embodiment. Figure 4 is a schematic cross-sectional view illustrating the manufacturing process of the substrate according to the first embodiment. Figure 5 is a schematic cross-sectional view illustrating the manufacturing process of the substrate according to the first embodiment. Figure 6 is a schematic cross-sectional view of the substrate according to the first embodiment. Figure 7 is a schematic plan view of the substrate according to the first embodiment. Figure 8 is a schematic cross-sectional view of an electronic component module with electronic components mounted on the substrate according to the first embodiment. Figure 9 is a schematic cross-sectional view of a modified substrate according to the first embodiment. Figure 10 is a schematic cross-sectional view illustrating the manufacturing process of the substrate according to the second embodiment. Figure 11 is a schematic cross-sectional view illustrating the manufacturing process of the substrate according to the second embodiment. Figure 12 is a schematic cross-sectional view illustrating the manufacturing process of the substrate according to the second embodiment. Figure 13 is a schematic cross-sectional view illustrating the manufacturing process of the substrate according to the second embodiment. Figure 14 is a schematic cross-sectional view showing the manufacturing process of the substrate according to the second embodiment. Figure 15 is a schematic cross-sectional view showing the manufacturing process of the substrate according to the second embodiment. Figure 16 is a schematic cross-sectional view showing the manufacturing process of the substrate according to the second embodiment. Figure 17 is a schematic cross-sectional view of the substrate according to the second embodiment. Figure 18 is a schematic cross-sectional view of a modified substrate according to the second embodiment.

[0011] The “substrate” and “electronic component module” of this disclosure will be described in detail below. While drawings will be referenced as necessary, the illustrations are provided for illustrative purposes only to aid in understanding this disclosure, and their appearance and dimensional ratios may differ from those of the actual products.

[0012] In this specification, "plan view" refers to the form of an object viewed from above or below along the thickness direction based on the substrate or electronic component module. Furthermore, "cross-sectional view" refers to the form of an object viewed from a direction substantially perpendicular to the thickness direction based on the substrate or electronic component module (simply put, the form when cut by a plane parallel to the thickness direction). "Up / down direction" and "left / right direction," used directly or indirectly in this specification, correspond to the up / down direction and left / right direction in the figures, respectively. Unless otherwise specified, the same reference numeral or symbol indicates the same component / part or has the same meaning. In a preferred embodiment, the vertical downward direction (i.e., the direction in which gravity acts) can be considered as the "downward direction," and the opposite direction as the "upward direction."

[0013] <<Substrate of the First Embodiment>> The substrate 1a of the first embodiment of this disclosure comprises a plate material 10, an internal conductor 11, a copper electrode 12, and a first metal 21 (see Figures 6 and 7). Hereinafter, each component will be described in detail with reference to the drawings.

[0014] The plate material 10 is a plate-shaped member having a front surface and a back surface, and is sized to support the electronic component ED (see Figure 8). Although this is merely an example, the thickness of the plate material 10 may be 20 μm or more and 1000 μm or less, for example, 100 μm or more and 300 μm or less.

[0015] The plate material 10 may have insulating properties. In this specification, "insulating properties" means that the volume resistivity is 1 MΩcm or more. As a suitable insulating material, the plate material 10 may be selected from the group consisting of ceramic, glass, and resin, at least one of these. By using such a material for the plate material 10, appropriate insulating properties can be ensured even if an internal conductor 11 is provided inside the plate material 10, and relatively high substrate strength can be achieved.

[0016] An internal conductor 11 is provided inside the internal conductor plate material 10 (inside the through hole). The internal conductor 11 is provided to electrically connect the copper electrode 12 on the surface side and the copper electrode 12 on the back side of the plate material 10. Therefore, the internal conductor 11 may extend from the inside of the plate material 10 to the surface and back. Note that the internal conductor 11 does not need to extend in a straight line as shown in Figure 6, but may extend to the surface and back while bending.

[0017] The internal conductor 11 is preferably made of copper, considering the heat dissipation properties of the substrate 1a and the contact properties with the copper electrodes 12 described later. However, the internal conductor 11 may be made of a material other than copper that has good heat dissipation properties, or a material that has good contact properties with the copper electrodes 12.

[0018] The copper electrodes 12 are electrically connected to the internal conductor 11. More specifically, they may be provided on the front and / or back surfaces of the plate material 10. In the copper electrodes 12 shown in Figure 6, two electrodes may be provided on the front surface, and two electrodes may be provided on the back surface corresponding to the front surface electrodes. These electrodes correspond, for example, to the input terminal, output terminal, or anode or cathode. For example, the copper electrodes 12 on the front surface are electrically connected to an electronic component mounted on the substrate 1a, and the copper electrodes 12 on the back surface are electrically connected to an external circuit board. Although the copper electrodes 12 are shown as rectangular in the plan view in Figure 7, they are not limited to this shape.

[0019] Generally, copper is known to be a metal material with good conductivity, good heat dissipation, quickly diffusing heat so that the electrodes do not easily become hot, and readily alloys with tin during soldering, resulting in good contact with solder. Therefore, by using copper electrodes 12 in the substrate 1a of this embodiment, good conductivity and heat dissipation can be achieved while also improving adhesion between the substrate 1a and the electronic component ED, and between the substrate and the external circuit board.

[0020] The first metal, the first metal 21, is a metal with a higher Young's modulus than the copper electrode 12 mentioned above. More specifically, the first metal 21 may have a Young's modulus of 130 GPa or higher. The Young's modulus may be determined by referring to literature values ​​or by measuring it using a known measurement method. The first metal 21 is positioned spaced apart from the copper electrode 12 and aligned in a direction intersecting the thickness direction of the plate material 10 (for example, the horizontal direction). In other words, the first metal 21 is provided on the same plane as the surface of the plate material 10 on which the copper electrode 12 is arranged. The first metal 21 located between the copper electrodes 12 is shown as rectangular in the plan view in Figure 7, but is not limited to this shape.

[0021] Thus, in this embodiment, if the substrate 1a is provided with a first metal 21 having a higher Young's modulus than the copper electrode 12, spaced apart from the copper electrode 12 and aligned in a direction intersecting the thickness direction of the plate material 10, the substrate strength can be further improved compared to a substrate without the first metal. More specifically, the first metal 21 can prevent deformation of the substrate 1a due to stress being applied to the same plane as the copper electrode 12 when mounting the electronic component ED.

[0022] As a suitable material for the first metal 21, at least one may be selected from the group consisting of copper alloys, nickel, nickel alloys, tungsten, carbon steel, stainless steel, alloy tool steel, machine structural alloy steel, high-tensile steel, and cemented carbide. "Copper alloy" refers to an alloy in which copper is the main component and other metallic elements are added (e.g., brass, bronze, cupronickel, beryllium copper, lead brass, lead bronze). "Nickel alloy" refers to an alloy in which nickel is the main component and other metallic elements are added (e.g., iron, chromium, molybdenum, cobalt, etc.). "Carbon steel" refers to iron-based steel in which carbon is the main alloying element. "Stainless steel" refers to an alloy of iron and chromium, which may also contain nickel, carbon, etc. "Alloy tool steel" refers to steel in which alloying elements such as chromium, tungsten, molybdenum, and vanadium are added to the carbon steel mentioned above. "Alloy steel for machine structures" refers to steel to which alloying elements such as chromium, nickel, molybdenum, and manganese have been added to carbon steel. "High-tensile steel" refers to steel with a tensile strength of 490 MPa or higher. "Cemented carbide" refers to alloys in which carbides of metals from groups IVa, Va, and VIa of the periodic table are sintered with iron-based metals such as iron, cobalt, and nickel. All of the above metal materials have a Young's modulus of 130 GPa or higher, which can further improve the strength of the substrate.

[0023] One of the features of the first metal 21 in this embodiment is that it does not need to be used as electrical wiring. In other words, since the first metal 21 is not used as electrical wiring, it is not used for power supply. Therefore, it is possible to prevent the generation of heat in the first metal 21 caused by the flow of electric current, and to further improve the strength of the substrate.

[0024] In this embodiment, the first metal 21 may be placed between the two copper electrodes 12. In particular, the space between the two copper electrodes 12 is a position where stress is easily applied when electrically connecting the copper electrodes 12 to the electronic component ED (or the copper electrodes to an external circuit board) via solder. Therefore, by placing the first metal 21 in the space between the copper electrodes 12 where this stress is easily applied, the strength of the substrate can be improved more effectively.

[0025] Here, the thickness T1 (see Figure 6) of the first metal 21 placed between the two copper electrodes 12 may be thinner than the thickness T2 of the copper electrodes 12. Setting the thickness of the first metal 21 in this way prevents interference by the first metal 21 from hindering the electrical connection when electrically connecting the copper electrodes 12 to the electronic component ED (or the copper electrodes to an external circuit board).

[0026] Furthermore, the first metal 21 may be provided spanning from the front (or back) surface to the side surface of the plate material 10. The first metal 21 may be arranged along the outer circumference of the plate material 10 (see Figure 7). More specifically, the first metal 21 may be provided so as to cover the outer edge of the plate material 10. In this way, when the first metal 21 is provided spanning from the front (or back) surface to the side surface of the plate material 10, a structure can be created that makes it difficult for moisture (or water vapor) to enter the electronic component ED. Specifically, referring to Figure 8, it can be assumed that moisture entering from the substrate 1a toward the electronic component ED will enter along the interface between the plate material 10 and the first metal 21. Therefore, as shown in Figure 6, when the first metal 21 is provided spanning from the front (or back) surface to the side surface of the plate material 10, the length of the interface between the first metal 21 and the plate material 10 can be increased. Thus, it can be made difficult for moisture to enter from the substrate 1a toward the electronic component ED. Furthermore, since the outer edge of the plate material 10 is covered with the first metal 21, the amount of moisture that penetrates from the outer edge of the plate material 10 through the plate material 10 toward the electronic component ED can be reduced.

[0027] Here, the thickness T3 (see Figure 6) of the first metal 21, which is provided extending from the surface (or back) to the side of the plate material 10, may be thicker than the thickness T2 of the copper electrode 12. The reason for this thickness relationship will be explained with reference to Figure 8. As shown in Figure 8, when packaging, it is conceivable to weld the covering member CM that covers the electronic component ED to the first metal 21. Here, when welding, by making the thickness T3 of the first metal 21 relatively thick, heat absorption during welding can be made easier. Also, in order to make heat absorption easier, it is preferable that the first metal 21 be a metal with high thermal conductivity. As an example, the first metal 21 may be stainless steel. This allows for proper welding of the first metal 21 to the covering member CM.

[0028] In light of the above, one specific feature of the first metal 21 is that the thickness T1 of the first metal 21 placed between the two copper electrodes 12 may be thinner than the thickness T3 of the first metal 21 that extends from the surface or back surface to the side surface (see Figure 6). With such a configuration, the interference of electrical connection by the copper electrodes 12 by the first metal 21 is reduced, and electronic components can be packaged by appropriate welding using the first metal 21.

[0029] In the embodiment shown in Figure 6, the first metal 21 is shown to be provided on the surface of the plate material 10 between adjacent copper electrodes 12. However, the embodiment is not limited to this, and for example, it may be provided on the back surface of the plate material 10 between adjacent copper electrodes 12, or on both the front and back surfaces of the plate material 10. Furthermore, the first metal 21 provided spanning from the front surface to the side surface of the plate material 10 is not limited to the example shown in Figure 6, and for example, it may be provided spanning from the front surface to the side surface and from the side surface to the back surface of the plate material 10.

[0030] <<Substrate of Modified Example of the First Embodiment>> Next, the substrate 1b of the modified example of the first embodiment will be described with reference to Figure 9. In describing the substrate 1b of the modified example, the configurations that are common to the substrate 1a of the first embodiment described above will be omitted from the explanation as appropriate.

[0031] In the modified substrate 1b of the first embodiment, as shown in Figure 9, the internal conductor 11 may have a multilayer structure. Specifically, the internal conductor 11 comprises a first internal conductor 11a extending from the inside of the plate material 10 toward the surface in the thickness direction of the plate material 10, and a second internal conductor 11b extending from the inside of the plate material 10 toward the back in the thickness direction of the plate material 10. The first internal conductor 11a and the second internal conductor 11b are electrically connected by a further internal conductor 11 extending in a direction intersecting the thickness direction.

[0032] In the modified substrate 1b of the first embodiment, the first internal conductor 11a and the second internal conductor 11b do not need to overlap in a plan view. In other words, in a planar perspective view, the first internal conductor 11a and the second internal conductor 11b may be offset in a direction intersecting the thickness direction of the plate material 10. With this configuration, it is possible to create a structure that makes it even more difficult for moisture (or water vapor) to enter the electronic component ED. More specifically, it is conceivable that moisture entering from the substrate 1b toward the electronic component ED will enter through a path that travels along the interface between the plate material 10 and the copper electrode 12 and the interface between the plate material 10 and the internal conductor 11. Therefore, as shown in Figure 9, if the first internal conductor 11a and the second internal conductor 11b are arranged so that they do not overlap in a plan view, the path that travels along the interface between the plate material 10 and the internal conductor 11 can be made longer than that of the substrate 1a shown in Figure 6. Thus, it is possible to make it more difficult for moisture to enter from the substrate 1b toward the electronic component ED. Furthermore, since the outer edge of the plate material 10 is covered with the first metal 21, the amount of moisture that penetrates from the outer edge of the plate material 10 through the plate material 10 toward the electronic component ED can be reduced.

[0033] It is preferable that the portion of the internal conductor 11 that extends perpendicular to the thickness direction of the plate material 10 (that is, the portion of the internal conductor 11 that extends horizontally between the first internal conductor 11a and the second internal conductor 11b in the thickness direction in Figure 9) has a larger area than the copper electrode 12 in a plan view. With this configuration, the area occupied by the internal conductor 11 located inside the plate material 10 on the substrate 1b in a plan view can be increased. Therefore, the number of paths through which moisture can enter via the plate material 10 can be reduced, making it even more difficult for moisture (or water vapor) to enter the electronic component ED.

[0034] <<Manufacturing Method of Substrate in the First Embodiment>> The manufacturing method of the substrate in the first embodiment will be described with reference to Figures 1 to 6.

[0035] First, a plate material 10 is prepared, selected from the group consisting of ceramic, glass, and resin, and copper foil CF is bonded to the front and back surfaces of the plate material 10, as shown in Figure 1. The bonding of the copper foil CF may be carried out by a well-known bonding method.

[0036] Next, in order to process the bonded copper foil to form copper electrodes, a photoresist PR is placed at the position where the copper electrodes 12 will be formed, as shown in Figure 2. The placement of the photoresist PR is done using known photolithography techniques.

[0037] Then, as shown in Figure 3, the region where the copper foil CF is exposed is etched using the photoresist PR as a mask. Known etching techniques (e.g., wet etching or dry etching) are used to etch the copper foil.

[0038] Then, in order to arrange the internal conductor 11 inside the plate material 10, a through hole H1 is formed at the position where the internal conductor 11 will be formed, as shown in Figure 4. Examples of how the through hole H1 can be formed include, in addition to the etching technique described above, laser processing technique, and techniques for physically forming the through hole using a drill or the like.

[0039] Then, as shown in Figure 5, metal is embedded in the formed through hole H1. Here, the manufacturing process can be simplified by using the same metal material (copper) for the internal conductor 11 and the copper electrode 12, but the metal of the internal conductor 11 does not have to be copper.

[0040] Then, as shown in Figure 6, the first metal 21 is formed between the pair of copper electrodes 12 and extending from the front (or back) to the side of the plate material 10. The method for forming the first metal 21 may be to process the metal material constituting the first metal 21 into a shape that conforms to the front and side of the plate material 10 and then bond it to the plate material 10, or to employ known film formation techniques (for example, physical vapor deposition (PVD), chemical vapor deposition (CVD), or electrochemical methods (plating)). Furthermore, the first metal 21 between the pair of copper electrodes 12 and the first metal 21 extending from the front (or back) to the side of the plate material 10 may be formed simultaneously, or they may be formed in separate processes. If formed in separate processes, the thickness of the first metal 21 between the pair of copper electrodes 12 and the thickness of the first metal 21 extending from the front (or back) to the side of the plate material 10 can be made different.

[0041] Through the above manufacturing process, the substrate 1a of the first embodiment can be manufactured. Furthermore, according to the substrate 1a of the first embodiment, copper electrodes, which have better conductivity than stainless steel, are used, and a first metal 21 with a higher Young's modulus than the copper electrodes 12 is positioned at a distance from the copper electrodes 12 and in a direction intersecting the thickness direction of the plate material 10, thereby further improving conductivity and substrate strength.

[0042] <<Substrate of the Second Embodiment>> Next, the substrate 1c of the second embodiment will be described with reference to Figure 17. In describing the substrate 1c of the second embodiment, configurations common to the substrates 1a and 1b of the first embodiment described above will be omitted from the explanation as appropriate.

[0043] As shown in Figure 17, in the second embodiment, the substrate 1c has a second metal 22 with a higher Young's modulus than the copper electrode 12 arranged inside the plate material 10. In this way, in the substrate 1c of the second embodiment, by further arranging the second metal 22 with a higher Young's modulus than the copper electrode 12 inside the plate material 10, the substrate strength can be further improved.

[0044] The second metal 22 may be the same metal as the first metal 21, or may be a different metal from the first metal 21. As an example, when the first metal 21 and the second metal 22 are made different materials, the first metal 21 may employ a metal with a relatively high Young's modulus with emphasis on Young's modulus, and the second metal 22 may employ a metal with higher thermal conductivity than the first metal 21 with emphasis on the heat dissipation performance of the substrate 1c. Examples of materials for the second metal 22 that have a higher Young's modulus than copper and relatively good thermal conductivity include nickel (Young's modulus: 207 GPa, thermal conductivity: 90.5 W / (m·K)), carbon steel (Young's modulus: 205 GPa, thermal conductivity: 37 to 60 W / (m·K)), and tungsten (Young's modulus: 345 GPa, thermal conductivity: 178 W / (m·K)). In this way, by adopting a material with better heat dissipation performance for the second metal 22 than the first metal 21, not only the strength of the substrate can be improved, but also the heat dissipation performance of the substrate 1c can be improved.

[0045] As a preferred embodiment of the second metal 22, the second metal 22 may extend to the side surface of the plate material 10. By extending the second metal 22 to the side surface of the plate material 10 in this manner, the second metal 22 can be extended as much as possible in a direction intersecting the thickness direction of the plate material 10, and the heat dissipation performance of the substrate 1c can be further improved.

[0046] Furthermore, as a preferred embodiment of the second metal 22, the second metal 22 may be in contact with the first metal 21 located on the side surface. With this configuration, it is possible to obtain a structure in which moisture (or water vapor) is even less likely to enter the electronic component ED. Specifically, as shown in FIG. 17, by bringing the first metal 21 located on the side surface into contact with the second metal 22, the path through which moisture penetrates along the interface between the first metal 21 and the plate material 10 can be made longer than that of the substrate 1a shown in FIG. 6. Therefore, the amount of moisture that intrudes from the substrate 1c toward the electronic component ED can be reduced.

[0047] <<Substrate according to Modification of the Second Embodiment>> Next, a substrate 1d according to a modification of the second embodiment will be described with reference to FIG. 18. In the description of the substrate 1d of the modification, the description of the configurations common to the substrate 1c of the second embodiment described above will be omitted as appropriate.

[0048] In the substrate 1d according to the modification of the second embodiment, as shown in FIG. 18, the inner conductors 11 may have a multilayer structure. Specifically, the inner conductors 11 comprise: a first inner conductor 11a extending in the thickness direction of the plate material 10 toward the surface side of the plate material 10; a second inner conductor 11b extending in the thickness direction of the plate material 10 toward the back side of the plate material 10; and a third inner conductor 11c extending in the thickness direction of the plate material 10 from the first inner conductor 11a toward the second inner conductor 11b. The first inner conductor 11a and the third inner conductor 11c are electrically connected by a further inner conductor 11 extending in a direction intersecting the thickness direction, and the second inner conductor 11b and the third inner conductor 11c are electrically connected by a further inner conductor 11 extending in a direction intersecting the thickness direction.

[0049] In the substrate 1d according to the modification of the second embodiment, in a plan view, the first inner conductor 11a, the second inner conductor 11b, and the third inner conductor 11c do not need to overlap each other. In other words, in perspective view through the plate, the first inner conductor 11a, the second inner conductor 11b, and the third inner conductor 11c may be arranged offset in a direction intersecting the thickness direction of the plate material 10. With this configuration, particularly the path propagating along the boundary surface between the plate material 10 and the inner conductor 11 can be made longer than that of the substrate 1b shown in FIG. 9. Therefore, moisture entering from the substrate 1d toward the electronic component ED can be reduced.

[0050] Among the inner conductors 11, a portion extending in a direction perpendicular to the thickness direction of the plate material 10 (for example, the inner conductor 11 located between the first inner conductor 11a and the third inner conductor 11c in the thickness direction in FIG. 18, or the portion where the inner conductor 11 located between the third inner conductor 11c and the second inner conductor 11b in the thickness direction extends in the horizontal direction) preferably has a larger area than the copper electrode 12 in plan view. With this configuration, the area occupied by the inner conductor 11 located inside the plate material 10 in the substrate 1b can be increased in plan view. Therefore, the number of moisture intrusion paths entering via the plate material 10 can be reduced, so that a structure in which moisture (or water vapor) is even less likely to enter the electronic component ED can be obtained.

[0051] <<Method for Manufacturing Substrate of Second Embodiment>> The method for manufacturing the substrate of the second embodiment will be described with reference to FIGS. 10 to 17.

[0052] First, as shown in Figure 10, a second metal 22 with a higher Young's modulus than the copper electrode is prepared, with through holes H2 provided in the positions where the internal conductor 11 is arranged.

[0053] Next, sheets ST, selected from the group consisting of uncured ceramic, glass, and resin, are attached to the upper and lower surfaces of the prepared second metal 22 to prepare a plate material with the second metal 22 inside, as shown in Figure 11. This attachment may be performed by thermocompression bonding as an example, but is not limited to thermocompression bonding.

[0054] Then, as shown in Figure 12, copper foil CF is bonded to the front and back surfaces of the plate material 10. The bonding of the copper foil CF may be carried out by a well-known bonding method.

[0055] Then, in order to process the bonded copper foil to form copper electrodes, a photoresist PR is placed at the position where the copper electrodes 12 will be formed, as shown in Figure 13. The placement of the photoresist PR is done using known photolithography techniques.

[0056] Then, as shown in Figure 14, the region where the copper foil CF is exposed is etched using the photoresist PR as a mask. Known etching techniques (e.g., wet etching or dry etching) are used to etch the copper foil.

[0057] Then, in order to arrange the internal conductor 11 inside the plate material 10, a through hole H1 is formed at the position where the internal conductor 11 will be formed, as shown in Figure 15. Examples of how the through hole H1 can be formed include, in addition to the etching technique described above, laser processing technique, and techniques for physically forming the through hole using a drill or the like.

[0058] Then, as shown in Figure 16, metal is embedded in the formed through hole H1. Here, the manufacturing process can be simplified by using the same metal material (copper) for the internal conductor 11 and the copper electrode 12, but the metal of the internal conductor 11 does not have to be copper.

[0059] Then, as shown in Figure 17, the first metal 21 is formed between the pair of copper electrodes 12 and across the surface (or back) to the side of the plate material 10. The method for forming the first metal 21 may be to process the metal material constituting the first metal 21 into a shape that conforms to the surface and side of the plate material 10 and then bond it to the plate material 10, or to employ known film formation techniques (for example, physical vapor deposition (PVD), chemical vapor deposition (CVD), or electrochemical methods (plating)). Furthermore, the first metal 21 between the pair of copper electrodes 12 and the first metal 21 across the surface (or back) to the side of the plate material 10 may be formed simultaneously, or they may be formed in separate steps. If formed in separate steps, the thickness of the first metal 21 between the pair of copper electrodes 12 and the thickness of the first metal 21 across the surface (or back) to the side of the plate material 10 can be made different.

[0060] Through the above manufacturing process, the substrate 1c of the second embodiment can be manufactured. Furthermore, according to the substrate 1c of the second embodiment, copper electrodes with better conductivity than stainless steel are used, and a first metal 21 with a higher Young's modulus than the copper electrodes 12 is positioned at a distance from the copper electrodes 12 and in a direction intersecting the thickness direction of the plate material 10, thereby further improving conductivity and substrate strength. Moreover, since the substrate 1c of the second embodiment has a second metal 22 with a higher Young's modulus than the copper electrodes 12 positioned inside the plate material 10, further improvement in substrate strength can be achieved.

[0061] <<Electronic Component Module>> Next, an electronic component module M in which electronic component ED is arranged on the substrate 1a of the first embodiment described above will be explained with reference to Figure 8. In this explanation, an electronic component module using the substrate 1a (1b) of the first embodiment described above will be explained, but substrates 1c and 1d of the second embodiment may also be used.

[0062] As shown in Figure 8, the electronic component ED is placed on the copper electrode 12 on the surface side of the substrate 1a. In this embodiment, since the substrate 1a uses copper electrodes 12, the electronic component ED can be electrically connected via solder.

[0063] In this embodiment, the electronic component module M may be packaged by welding the first metal 21 and the covering member CM. Therefore, the first metal 21 of the substrate 1a is preferably a metal with high thermal conductivity to facilitate welding. As an example, the first metal 21 may be stainless steel. This allows for proper welding of the first metal 21 and the covering member CM.

[0064] Furthermore, as described above, the substrates 1a and 1b of the first embodiment and the substrates 1c and 1d of the second embodiment have a structure that makes it difficult for moisture (or water vapor) to enter the electronic component ED. Therefore, even electronic components that are considered relatively sensitive to moisture (or water vapor) can be appropriately packaged on the substrate 1. Examples of electronic component ED include solid-state batteries or quartz crystal oscillators. However, electronic component ED is not limited to solid-state batteries or quartz crystal oscillators.

[0065] The embodiments disclosed herein are illustrative in all respects and do not constitute a limiting interpretation. Therefore, the technical scope of this disclosure is not construed solely by the embodiments described above, but is defined based on the claims. Furthermore, the technical scope of this disclosure includes all modifications within the meaning and scope of equivalence to the claims.

[0066] This disclosure can be suitably used in substrates and electronic component modules that have improved conductivity and substrate strength.

[0067] 1, 1a-1d Substrate 10 Plate material 11 Internal conductor 11a First internal conductor 11b Second internal conductor 11c Third internal conductor 12 Copper electrode 21 First metal 22 Second metal ED Electronic component CM Coating material CF Copper foil PR Photoresist H1, H2 Through hole ST Sheet M Electronic component module

Claims

1. A substrate comprising: a plate material; copper electrodes provided on the surface and / or back surface of the plate material; an internal conductor provided inside the plate material and extending from the inside of the plate material to the surface and back surface; and a first metal positioned spaced apart from the copper electrodes and aligned in a direction intersecting the thickness direction of the plate material, wherein the internal conductor is electrically connected to the copper electrodes, and the Young's modulus of the first metal is higher than that of the copper electrodes.

2. The substrate according to claim 1, wherein the first metal is selected from the group consisting of copper alloys, nickel, nickel alloys, tungsten, carbon steel, stainless steel, alloy tool steel, machine structural alloy steel, high-tensile steel, and cemented carbide.

3. The substrate according to claim 1 or 2, wherein the plate material is selected from the group consisting of ceramic, glass, and resin, at least one of these materials.

4. The substrate according to any one of claims 1 to 3, wherein the first metal is not used as electrical wiring.

5. The substrate according to any one of claims 1 to 4, wherein the plate material has sides that intersect with the surface and the back surface, and the first metal is provided spanning from the surface or the back surface to the sides.

6. The substrate according to claim 5, wherein the thickness of the first metal provided across the side surface is greater than the thickness of the copper electrode.

7. The substrate according to any one of claims 1 to 6, wherein at least two copper electrodes are provided, and the first metal is disposed between the two copper electrodes.

8. The substrate according to claim 7, wherein the plate material has sides that intersect with the front surface and the back surface, the first metal is provided spanning from the front surface or the back surface to the side surface, and the thickness of the first metal positioned between the two copper electrodes is thinner than the thickness of the first metal provided spanning from the front surface or the back surface to the side surface.

9. The substrate according to any one of claims 1 to 8, wherein the first metal is provided on both the front surface and the back surface.

10. The substrate according to any one of claims 1 to 9, wherein a second metal with a higher Young's modulus than the copper electrode is further arranged inside the plate material.

11. The substrate according to claim 10, wherein the second metal is a material with better heat dissipation properties than the first metal.

12. The substrate according to claim 10 or 11, wherein the plate material has side surfaces that intersect with the surface and back surfaces, and the second metal extends to the side surfaces.

13. The substrate according to any one of claims 10 to 12, wherein the plate material has sides that intersect with the front surface and the back surface, the first metal is provided spanning from the front surface or the back surface to the side surface, and the second metal is in contact with the first metal located on the side surface.

14. The substrate according to any one of claims 1 to 13, wherein the internal conductor comprises at least a first internal conductor and a second internal conductor, and in a plan view, the first internal conductor and the internal conductor do not overlap each other.

15. The substrate according to any one of claims 1 to 14, wherein the portion of the internal conductor that extends perpendicular to the thickness direction of the plate material has a larger area than the copper electrode in a plan view.

16. An electronic component module comprising a substrate according to any one of claims 1 to 15, and an electronic component mounted on the substrate.

17. The electronic component module according to claim 16, wherein the electronic component is a solid-state battery or a quartz crystal oscillator.

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