Module substrate and electronic device

Abstract

The invention provides a module substrate and an electronic device. The outer surfaces of a multi-layer substrate or the outer surfaces of parts of the module substrate including the multi-layer substrate and a mounting component are set as appropriate surfaces, so that the electrical characteristics and the mechanical characteristics are excellent. A module substrate (301) is provided with a multilayer substrate (101) and a mounting member (201). A multilayer substrate (101) is provided with a plurality of resin layers and a conductor layer attached to a predetermined resin layer among the plurality of resin layers, and has a first surface (S1) and a second surface (S2) that constitute a front-back relationship. A multilayer substrate (101) has an external electrode (1) on a first surface (S1). When Rz1 represents the maximum height roughness of a region facing the mounting portion of the multilayer substrate (101), Rz2 represents the maximum height roughness of the mounting portion on the second surface (S2) of the multilayer substrate (101), and Rz3 represents the maximum height roughness of a region where the radiation electrode of the mounting member (201) is formed, the relationship Rz1 < Rz2 < Rz3 is satisfied.

Description

Technical Field

[0001] The present invention relates to a module substrate including a multilayer substrate obtained by laminating resin layers and a mounting component mounted on the multilayer substrate, and an electronic device including the module substrate. Background Art

[0002] Patent Document 1 discloses a multilayer substrate comprising a plurality of resin layers, a conductor layer attached to one surface of the resin layers, and interlayer connection conductors formed within a predetermined resin layer. It also discloses a module substrate in which a radiation electrode is laminated on a portion of the multilayer substrate.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2017 / 051649

[0006] The resin layers and the outer surfaces of the conductor layers constituting the multilayer substrate in the lamination direction, and the mounting surfaces and outer surfaces of the mounting components mounted on the multilayer substrate are all uniform surfaces without distinction. Summary of the Invention

[0007] Problems to be solved by the invention

[0008] The inventors of this application have discovered that it is important for each outer surface of a multilayer substrate, or each outer surface of a module substrate comprising a multilayer substrate and components mounted thereon, to be an appropriate surface from the perspectives of electrical and mechanical properties. This concept has not been previously accepted.

[0009] For example, when a mounted component functions as a standalone antenna or as a primary antenna, the outer surface of the mounted component is important from the perspective of antenna characteristics. Furthermore, from the perspective of mechanical properties, it is important that the bonding surface between the multilayer substrate and the mounted component is an appropriate surface. Furthermore, the outer surface of the module substrate is sometimes required to serve as a mounting surface.

[0010] Therefore, the object of the present invention is to provide a module substrate having excellent electrical and mechanical characteristics by setting the outer surfaces of a multilayer substrate or the outer surfaces of each part of a module substrate including a multilayer substrate and mounted components to appropriate surfaces, and an electronic device equipped with the module substrate.

[0011] Technical solutions to solve problems

[0012] (1) A module substrate as an example of the present disclosure is characterized by comprising:

[0013] a multilayer substrate having a plurality of resin layers and a conductor layer attached to a predetermined resin layer among the plurality of resin layers; and

[0014] a mounting component including an insulator and a radiation electrode formed on the insulator and mounted on the multilayer substrate;

[0015] The multilayer substrate has a first surface and a second surface forming a front-back relationship.

[0016] The multilayer substrate has external electrodes exposed on the first surface.

[0017] The multi-layer substrate has a mounting portion for mounting the component on a portion of the second surface of the multi-layer substrate.

[0018] The mounting component has a mounting surface in contact with the mounting portion of the multi-layer substrate.

[0019] The radiation electrode is formed on a surface separated from the mounting surface or in a region along the surface.

[0020] The resin layer at the mounting portion of the multilayer substrate is directly bonded to the insulator at the mounting surface of the mounting component.

[0021] When Rz1 represents the maximum height roughness of the mounting portion opposing region of the first surface of the multilayer substrate, with the width of the mounting portion opposing region being the reference length of the cross-sectional curve of the mounting portion opposing region; Rz2 represents the maximum height roughness of the mounting portion of the second surface of the multilayer substrate, with the width of the mounting portion being the reference length of the cross-sectional curve of the mounting portion; and Rz3 represents the maximum height roughness of the surface of the insulator, with the width of the radiation electrode formation region being the reference length of the cross-sectional curve of the insulator, the relationship Rz1<Rz2<Rz3 is satisfied.

[0022] (2) An electronic device as an example of the present disclosure is characterized by including:

[0023] the module substrate; and

[0024] Other substrates on which the module substrate is mounted.

[0025] (3) An electronic device as an example of the present disclosure is characterized by including:

[0026] the module substrate; and

[0027] A housing that houses the module substrate.

[0028] Effects of the Invention

[0029] According to the present invention, a module substrate having excellent electrical and mechanical properties can be obtained by setting the outer surfaces of a multilayer substrate or the outer surfaces of each part of a module substrate including a multilayer substrate and mounted components to appropriate surfaces, and an electronic device equipped with the module substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The lower part is a cross-sectional view of the module substrate 301 according to the first embodiment. Figure 1 The upper portion is a cross-sectional view of the mounting component 201 before being mounted on the multi-layer substrate 101 .

[0031] Figure 2 The lower part is a cross-sectional view of the module substrate 302 according to the second embodiment. Figure 2 The upper portion is a cross-sectional view of the mounting component 202 before being mounted on the multi-layer substrate 102 .

[0032] Figure 3 The lower part is a cross-sectional view of the module substrate 303 according to the third embodiment. Figure 3 The upper portion is a cross-sectional view of the mounting component 203 before being mounted on the multi-layer substrate 103 .

[0033] Figure 4 It is a cross-sectional view of a module substrate 304 according to the fourth embodiment.

[0034] Figure 5 It is a cross-sectional view of a module substrate 305 according to the fifth embodiment.

[0035] Figure 6 It is a cross-sectional view of a module substrate 306 according to the sixth embodiment.

[0036] Figure 7 It is a cross-sectional view of an electronic device 407 according to the seventh embodiment.

[0037] Description of Reference Numerals

[0038] BM…connecting conductor;

[0039] CA…depression;

[0040] GL…ground conductor layer;

[0041] IS…Decent insulation;

[0042] RS…resin surface;

[0043] S1…Side 1;

[0044] S2…side 2;

[0045] SL1, SL2, SLa, SLb... conductor patterns for signal lines;

[0046] 1…external electrode;

[0047] 2, 2a, 2b ... multi-layer substrate side pad electrode;

[0048] 4…Interlayer connecting conductor;

[0049] 5…conductor foil;

[0050] 6, 6a, 6b…terminal electrodes;

[0051] 7, 7a, 7b…radiating electrodes;

[0052] 8…electrodes;

[0053] 9…Plated through hole;

[0054] 10…resin parts;

[0055] 11, 12, 13, 14, 15…resin layer;

[0056] 24…electronic components;

[0057] 25…connector;

[0058] 27…other substrates;

[0059] 41 ... other substrate side pad electrodes;

[0060] 42 ... component side pad electrode;

[0061] 101, 102, 104, 105, 106…multi-layer substrate;

[0062] 201, 202, 203, 205, 206…carrying parts;

[0063] 301, 302, 303, 304, 305, 306…module substrate;

[0064] 407…Electronic equipment. DETAILED DESCRIPTION

[0065] Hereinafter, several specific examples will be given with reference to the accompanying drawings to illustrate a plurality of ways of implementing the present invention. The same reference numerals are used for the same parts in each figure. Taking into account the ease of explanation or understanding of the key points, the ways of implementing the invention are divided into a plurality of embodiments for representation, but it is possible to omit, replace or combine parts of the structures shown in different embodiments. After the second embodiment, the description of matters common to the first embodiment is omitted, and only the differences are described. In particular, the same effects produced by the same structure are not mentioned one by one in each embodiment.

[0066] First Implementation Method

[0067] In the first embodiment, an example of a module substrate is shown in which mounting components are mounted on a multi-layer substrate.

[0068] Figure 1 The lower part is a cross-sectional view of the module substrate 301 according to the first embodiment. Figure 1 The upper part is a cross-sectional view of the mounting component 201 before being mounted on the multi-layer substrate 101. Figure 1 In the figure, even when the mounting component 201 has multiple insulating layers, the interface between two adjacent insulating layers in the layer direction is not shown. Furthermore, in the cross-sectional view, lines appearing in the cross section (due to cutting) are depicted, and lines located behind the cross section are omitted. This applies to the various embodiments shown below.

[0069] The module substrate 301 includes a multilayer substrate 101 and a mounted component 201. The multilayer substrate 101 includes a plurality of resin layers 11, 12, 13, 14, and 15, and conductor layers and interlayer connection conductors attached to predetermined resin layers among the plurality of resin layers.

[0070] A connecting conductor BM is formed by coating in the openings of the resin layer 15. The connecting conductor BM is, for example, a molten metal such as solder. A plurality of substrate-side pad electrodes 2a and 2b are formed below the connecting conductor BM. In this example, the resin layers 11, 12, 13, 14, and 15 are a laminate of thermoplastic resin sheets with Cu foil bonded to one side.

[0071] like Figure 1 As shown in the upper part of FIG, the multilayer substrate 101 has a first surface S1 and a second surface S2 forming a front-back relationship. The resin surface RS is exposed on the second surface S2 of the multilayer substrate 101.

[0072] Radiating electrodes 7a, 7b and other electrodes 8 are formed on or near the upper surface of the mounting member 201, so that the mounting member 201 functions as a patch antenna or as a part of a patch antenna. The radiating electrodes 7a, 7b and the electrodes 8 are along the upper surface of the mounting member 201. Figure 1 In the upper portion, the width Wr shows the width of the radiation electrode formation region.

[0073] Terminal electrodes 6a and 6b are formed on the mounting surface (bottom surface) of the mounting component 201. Plated through holes 9 are formed between the terminal electrodes 6a and 6b and the radiation electrodes 7a and 7b. The insulator surface IS is exposed on the mounting surface (bottom surface) of the mounting component 201. Figure 1 In the upper portion, the width Wm represents the width of the mounting portion of the mounting component 201.

[0074] Here, Rz1 represents the maximum height roughness of the mounting portion facing region of the first surface S1 of the multilayer substrate 101, with the width Wm of the mounting portion facing region being the reference length of the cross-sectional curve of the mounting portion facing region. Rz1 is, for example, 4 μm.

[0075] Furthermore, Rz2 represents the maximum height roughness of the mounting portion on the second surface S2 of the multilayer substrate 101, with the width Wm of the mounting portion of the mounting component 201 being the reference length of the cross-sectional curve of the mounting portion. Rz2 is, for example, 50 μm.

[0076] Furthermore, Rz3 represents the maximum height roughness of the surface of the insulator, with the width Wr of the region where the radiation electrodes 7a and 7b are formed being the reference length of the cross-sectional curve of the insulator mounting member 201. Here, the "surface of the insulator" refers to the surface of the insulator where the radiation electrodes 7a and 7b are in contact.

[0077] The maximum height roughnesses Rz1, Rz2, and Rz3 are in the relationship of Rz1 < Rz2 < Rz3. Thus, the module substrate 301 has three surfaces with different roughnesses (concavities and convexities).

[0078] When manufacturing the multilayer substrate 101, the stacked resin layers are pressed in contact with a smooth rigid object, thereby determining the maximum height roughness Rz1 of the first surface S1 of the multilayer substrate 101. Separately, the maximum height roughness Rz2 of the second surface S2 of the multilayer substrate 101 is determined by pressing in contact with an object having a smaller maximum height roughness.

[0079] When manufacturing the mounting member 201 , the maximum height roughness Rz3 of the upper surface of the mounting member 201 is determined by pressing an object having a large maximum height roughness in contact with the upper surface of the mounting member 201 .

[0080] The module substrate 301 is mounted on another substrate by connecting the external electrodes 1 of the multilayer substrate 101 to pad electrodes formed on another substrate described later. Alternatively, as described later, an electronic component mounted module substrate is formed by mounting electronic components on the external electrodes 1.

[0081] Signal line conductor patterns SL1 and SL2 and a ground conductor layer GL are formed inside the multilayer substrate 101. The signal line conductor patterns SL1 and SL2, the ground conductor layer GL, and the resin layer between the signal line conductor patterns SL1 and SL2 and the ground conductor layer GL each constitute two microstrip transmission lines.

[0082] like Figure 1 As shown, mounting component 201 is placed at a predetermined position on multilayer substrate 101, the entire assembly is heated to a predetermined temperature, and then pressed at a predetermined pressure. This causes connecting conductor BM to melt, electrically connecting pad electrodes 2a, 2b on the multilayer substrate side to terminal electrodes 6a, 6b on the mounting component 201 side. Furthermore, the insulator surface IS of mounting component 201 is directly bonded to the resin surface RS of multilayer substrate 101.

[0083] For example, the insulator material of the mounting component 201 is the same material as the resin layers 11, 12, 13, 14, and 15 of the multilayer substrate 101. This allows for high adhesion between the mounting component 201 and the multilayer substrate 101. For example, the insulator of the mounting component 201 and the resin layers 11, 12, 13, 14, and 15 of the multilayer substrate 101 are thermoplastic resins, such as liquid crystal polymer (LCP).

[0084] Fourier transform infrared spectrophotometry (FT-IR) can be used to confirm whether the resin materials are the same. Specifically, a spectrum can be obtained using FT-IR. If the peaks in the spectrum of the mounted component and the multilayer substrate are the same, it can be confirmed that they are made of the same resin material.

[0085] It should be noted that for thermoplastic resins, the difference in melting point between identical resin materials is relatively small. Differential Scanning Calorimetry (DSC) endothermic peaks can be used to confirm whether the resin portion of the multilayer substrate and the resin portion of the mounted component are made of the same resin material. Specifically, using a Rigaku DSC8230, the temperature can be raised at a rate of 10°C / minute, the melted resin material cooled, and then the temperature can be raised again at 10°C / minute. If the melting point difference between the two resin materials is within 5°C, the materials are considered to be identical.

[0086] The above-mentioned determination of same type / different type is also the same in other embodiments described below.

[0087] Thus, if a thermoplastic resin is used, a higher adhesion strength can be obtained between the mounting component 201 and the multi-layer substrate 101. In addition, if the resin layer of the multi-layer substrate 101 is a thermoplastic resin, it is easy to laminate the resin sheets at one time, and no separate bonding step is required. Therefore, the overall number of steps can be reduced, and the manufacturing cost can be reduced.

[0088] Furthermore, if the resin layer of the multilayer substrate 101 is a liquid crystal polymer resin, the water absorption rate of the multilayer substrate 101 is low, thereby suppressing the variation of the electrical characteristics in a humid environment and achieving a highly reliable module substrate.

[0089] The insulating material of the mounting component 201 and the resin layers 11, 12, 13, 14, and 15 of the multilayer substrate 101 may be made of different materials. For example, one of the resin layers 11, 12, 13, 14, and 15 of the multilayer substrate 101 and the insulating material of the mounting component 201 may be a thermoplastic resin and the other a thermosetting resin. Examples of thermosetting resins include polyimide resins and epoxy resins.

[0090] Alternatively, the insulator of the mounting component 201 may be ceramic. In this case, the insulator surface IS of the mounting component 201 and the resin surface RS of the multilayer substrate 101 can be directly bonded.

[0091] It should be noted that the resin layers of the multilayer substrate 101 do not need to be of the same type, and layers of different materials may be mixed. However, if the resin layer 15 forming the second surface S2 is a thermoplastic resin, direct bonding between the insulator surface IS of the mounting component 201 and the resin surface RS of the multilayer substrate 101 becomes easier.

[0092] Alternatively, the resin layer 15 forming the second surface S2 or the entirety of the resin layers 11 to 15 may be made of a thermosetting resin. In this case, at least the resin layer 15 may be made of a sheet in a pre-crosslinking state and cured by heating. In this case, the insulator surface IS of the mounting component 201 and the resin surface RS of the multilayer substrate 101 may be directly bonded.

[0093] Mounting component 201 is a component that meets the electrical characteristics required for an antenna. Therefore, the insulator material of mounting component 201 can be a material that achieves these required characteristics. For example, if a high dielectric constant is important for the insulator of mounting component 201, a material with a higher dielectric constant than the dielectric constant of the resin layer of multilayer substrate 101 can be used. This allows for the production of module substrate 301, an antenna having excellent electrical characteristics.

[0094] As described above, the maximum height roughness Rz1 of the first surface S1 of the multi-layer substrate 101 is smaller than the maximum height roughness Rz2 of the second surface S2 of the multi-layer substrate 101 .

[0095] The minimal maximum height roughness of the first surface S1 of the multilayer substrate 101 indicates that the mounting surface of the module substrate 301 is highly smooth. Consequently, when the module substrate 301 is mounted on another substrate, the module substrate can be easily mounted on the other substrate's highly flat mounting surface. Furthermore, when electronic components are mounted on the external electrodes 1 of the module substrate 301, the electronic components can be easily mounted on the highly flat lower surface of the module substrate 301 (the first surface S1 of the multilayer substrate 101).

[0096] As described above, the maximum height roughness Rz2 of the second surface S2 of the multi-layer substrate 101 is greater than the maximum height roughness Rz1 of the first surface S1 of the multi-layer substrate 101 .

[0097] By having a predetermined maximum height roughness on the second surface S2 of the multilayer substrate 101, the mounting component 201 has high adhesion to the second surface S2 of the multilayer substrate 101. In other words, the substantial contact area between the resin surface RS and the insulator surface IS is large, and thus the mounting component 201 has high adhesion to the second surface S2 of the multilayer substrate 101.

[0098] As described above, the maximum height roughness Rz3 of the surface (upper surface) of the mounting component 201 opposite to the mounting surface relative to the multilayer substrate 101 is greater than the maximum height roughness Rz1 of the first surface S1 of the multilayer substrate 101 and the maximum height roughness Rz2 of the second surface S2 of the multilayer substrate 101.

[0099] Because the maximum height roughness of the top surface of the mount component is greater, the electrical characteristics of the mount component as an antenna can be set to a predetermined level, compared to mount components with electrodes formed on or near flat surfaces. In the first embodiment, the top surface of the mount component 201 is provided with radiation electrodes 7a and 7b and another electrode 8. These radiation electrodes 7a and 7b, the ground conductor layer GL of the multilayer substrate 101, and the resin layer between the radiation electrodes 7a and 7b and the ground conductor layer GL of the multilayer substrate 101 form a patch antenna. Based on the maximum height roughness Rz3 of the top surface of the mount component 201, the antenna's directivity and other characteristics can be set to a predetermined level. This results in a module substrate with excellent electrical characteristics for the mount component or the electronic circuitry formed by the mount component and the multilayer substrate.

[0100] Second Implementation Method

[0101] In the second embodiment, a module substrate is exemplified in which the mounting structure of the mounted components on the multi-layer substrate is different from that of the first embodiment.

[0102] Figure 2 The lower part is a cross-sectional view of the module substrate 302 according to the second embodiment. Figure 2 The upper portion is a cross-sectional view of the mounting component 202 before being mounted on the multi-layer substrate 102 .

[0103] The module substrate 302 includes a multi-layer substrate 102 and a mounting component 202 .

[0104] The multilayer substrate 102 includes a plurality of resin layers 11 , 12 , 13 , 14 , and 15 , and conductor layers and interlayer connection conductors attached to predetermined resin layers of the plurality of resin layers.

[0105] The resin layer 15 of the multilayer substrate 102 has an opening formed therein, and a recess (cavity) CA is formed on the surface of the laminate through the opening. The mounting component 202 is mounted in the recess CA of the multilayer substrate 102 .

[0106] like Figure 2 As shown in the upper part of FIG, the resin surface RS is exposed on the second surface S2 of the multilayer substrate 102. In addition, the insulator surface IS is exposed on the lower surface of the mounting component 202.

[0107] The mounting component 202 includes a stacking direction conductor path formed by stacking resin sheets including interlayer connection conductors 4 and conductor foils 5 in contact with the interlayer connection conductors 4 .

[0108] Note that, by forming a stacking direction conductor path, it is also possible to form a concave and convex portion on the upper surface of the mounting component 202 .

[0109] As in the example shown in the first embodiment, when the maximum height roughness of the region facing the mounting portion on the first surface S1 of the multilayer substrate 102 is represented by Rz1, the maximum height roughness of the mounting portion on the second surface S2 of the multilayer substrate 102 is represented by Rz2, and the maximum height roughness of the surface of the insulator in the radiation electrode formation region of the mounting member 202 is represented by Rz3, the relationship Rz1<Rz2<Rz3 is established.

[0110] A plurality of external electrodes 1 are exposed on the first surface S1 of the multilayer substrate 102. Figure 2 In the state shown in the upper part of , a connection conductor BM is formed on the second surface (the surface within the recessed portion CA) of the multilayer substrate 102 so as to be electrically connected to the end portions of the signal line conductor patterns SL1 and SL2 .

[0111] Mounting component 202 is a laminated substrate comprising stacked resin layers. The resin material of each resin layer of mounting component 202 is the same as the resin material of each resin layer of multilayer substrate 102. For example, it is a thermoplastic resin. An example of such a thermoplastic resin is a liquid crystal polymer (LCP).

[0112] like Figure 2 As shown, the mounting component 202 is mounted in the recessed portion CA of the multilayer substrate 102, and the entire assembly is pressurized and heated to a predetermined temperature, thereby bonding the mounting component 202 to the recessed portion CA of the multilayer substrate 102. Specifically, the ends of the signal line conductor patterns SL1 and SL2 on the multilayer substrate side are electrically connected to the terminal electrodes 6a and 6b on the mounting component 202 side via the connecting conductor BM. Furthermore, the insulator surface IS of the mounting component 202 is directly bonded to the resin surface RS of the multilayer substrate 102.

[0113] It should be noted that the materials of the resin layers of the mounting component 202 are not limited to the same type, and layers of different materials may be mixed. In addition, the resin layers of the multilayer substrate 102 are not limited to the same type, and layers of different materials may be mixed.

[0114] Third Implementation Method

[0115] In the third embodiment, a bonding method is further exemplified for the material of the insulator on which the components are mounted and the material of the multilayer substrate.

[0116] Figure 3 The lower part is a cross-sectional view of the module substrate 303 according to the third embodiment. Figure 3 The upper portion is a cross-sectional view of the mounting component 203 before being mounted on the multi-layer substrate 101 .

[0117] The module substrate 303 includes the multi-layer substrate 101 and a mounting component 203. The mounting component 203 is mounted on the second surface S2 of the multi-layer substrate 101.

[0118] The multi-layer substrate 101 is the same as the multi-layer substrate 101 described in the first embodiment.

[0119] As in the example shown in the first embodiment, when the maximum height roughness of the region facing the mounting portion on the first surface S1 of the multilayer substrate 101 is represented by Rz1, the maximum height roughness of the mounting portion on the second surface S2 of the multilayer substrate 101 is represented by Rz2, and the maximum height roughness of the surface of the insulator in the radiation electrode formation region of the mounting member 203 is represented by Rz3, the relationship Rz1<Rz2<Rz3 is established.

[0120] The mounting member 203 is a laminated substrate having laminated resin layers. The resin material of each resin layer of the mounting member 203 is a different type of material from the resin material of each resin layer of the multilayer substrate 101. For example, the resin layer of the mounting member 203 is a thermosetting resin such as a polyimide resin or an epoxy resin, while the resin layers of the multilayer substrate 101 are a thermoplastic resin such as a liquid crystal polymer resin. Alternatively, for example, the resin layer of the multilayer substrate 101 is a thermosetting resin such as a polyimide resin or an epoxy resin, while the resin layers of the mounting member 203 are a thermoplastic resin such as a liquid crystal polymer resin.

[0121] like Figure 3 As shown, mounting component 203 is mounted on the upper surface of multilayer substrate 101, and the entire assembly is pressurized and heated, thereby bonding mounting component 203 to the upper surface of multilayer substrate 101. Specifically, pad electrodes 2a, 2b on the multilayer substrate side are electrically connected to terminal electrodes 6a, 6b on the mounting component 203 side. Furthermore, insulator surface IS of mounting component 203 is directly bonded to resin surface RS of multilayer substrate 101.

[0122] It should be noted that the resin layers of the multilayer substrate 101 do not need to be of the same type, and layers of different materials may be mixed. Furthermore, the resin sheets of the mounting component 203 do not need to be of the same type, and layers of different materials may be mixed. However, if the resin layer 15 forming the second surface S2 and / or the resin layer forming the mounting surface of the mounting component 203 is a thermoplastic resin, direct bonding between the insulator surface IS of the mounting component 201 and the resin surface RS of the multilayer substrate 101 becomes easier.

[0123] The resin layer 15 forming the second surface S2 and the resin layer forming the mounting surface of the mounting component 203 may also be a thermosetting resin. In this case, a sheet in a pre-crosslinking state may be used for the resin layer 15 forming the second surface S2 and / or the resin layer forming the mounting surface of the mounting component 203, and then cured by heating. In this case, the insulator surface IS of the mounting component 203 is directly bonded to the resin surface RS of the multilayer substrate 101.

[0124] Fourth Implementation Method

[0125] In the fourth embodiment, a module substrate including electronic components is exemplified.

[0126] Figure 4 2 is a cross-sectional view of a module substrate 304 according to the fourth embodiment. The module substrate 304 includes a multilayer substrate 104, a mounting component 201, and an electronic component 24. The electronic component 24 is not shown with hatching.

[0127] The multilayer substrate 104 includes a plurality of resin layers 11 , 12 , 13 , 14 , and 15 , and a conductor layer and an interlayer connection conductor attached to a predetermined resin layer among the plurality of resin layers.

[0128] A connecting conductor BM is formed by coating in the openings of the resin layer 15. The connecting conductor BM is, for example, a molten metal such as solder. A plurality of substrate-side pad electrodes 2a and 2b are formed below the connecting conductor BM. In this example, the resin layers 11, 12, 13, and 14 are a laminate of thermoplastic resin sheets with Cu foil attached to one side.

[0129] Signal line conductor patterns SL1 and SL2 and a ground conductor layer GL are formed inside the multilayer substrate 104. The signal line conductor patterns SL1 and SL2, the ground conductor layer GL, and the resin layer therebetween constitute two microstrip transmission lines.

[0130] like Figure 4As shown, mounting component 201 is placed at a predetermined position on multilayer substrate 104, the entire assembly is heated to a predetermined temperature, and then pressed at a predetermined pressure. This causes connecting conductor BM to melt, electrically connecting pad electrodes 2a, 2b on the multilayer substrate side to terminal electrodes 6a, 6b on the mounting component 201 side. Furthermore, the insulator surface IS of mounting component 201 is directly bonded to the resin surface RS of multilayer substrate 101.

[0131] The structure of the mounting member 201 is the same as that of the mounting member 201 shown in the first embodiment.

[0132] The external electrodes 1 are formed on the mounting surface (lower surface) of the multilayer substrate 104 . The component-side land electrodes 42 are formed on the mounting surface (upper surface) of the electronic component 24 .

[0133] The component-side land electrode 42 is connected to the external electrode 1 of the multilayer substrate 104 via the connection conductor BM. The connection conductor BM is, for example, a heated molten metal such as solder.

[0134] The electronic component 24 is, for example, an IC that amplifies the power of a transmission signal to supply power to an antenna, or an IC that amplifies a reception signal of the antenna.

[0135] According to the present embodiment, since the electronic component 24 has high mountability on the multi-layer substrate 104 , the electronic component 24 can be easily mounted on the multi-layer substrate 104 .

[0136] Fifth Implementation Method

[0137] In the fifth embodiment, a module substrate including a curved multi-layer substrate is exemplified.

[0138] Figure 5 1 is a cross-sectional view of a module substrate 305 according to the fifth embodiment. The module substrate 305 includes a multi-layer substrate 105 and a connector 25 mounted on the multi-layer substrate 105. Hatching is omitted in the illustration of the connector 25.

[0139] The maximum height roughness of the upper surface of the mounting member 205 is relatively large, so that the mounting member 205 functions as a patch antenna or as part of a patch antenna. In this example, the radiation electrode 7 is formed on the upper surface of the mounting member 205 or near the upper surface.

[0140] Terminal electrodes 6 are formed on the mounting surface (lower surface) of the mounting component 205. A laminate of multiple conductor foils 5 and multiple interlayer connection conductors 4 is formed between the terminal electrodes 6 and the radiation electrode 7. In this manner, stacking resin sheets including the interlayer connection conductors 4 and the conductor foils 5 in contact with them forms a stacking direction conductor path in the mounting component 205. This stacking direction conductor path forms a recessed portion on the surface (upper surface) of the mounting component 205 opposite the mounting surface (lower surface). The radiation electrode 7 extends along this recessed portion.

[0141] Here, Rz1 represents the maximum height roughness of the mounting portion facing region of the first surface S1 of the multilayer substrate 105 , which is a region facing the mounting portion of the mounting component 205 , with the width Wm of the mounting portion facing region being the reference length of the cross-sectional curve of the mounting portion facing region.

[0142] Furthermore, Rz2 represents the maximum height roughness of the mounting portion on the second surface S2 of the multilayer substrate 105 , with the width Wm of the mounting portion of the mounting component 205 being the reference length of the cross-sectional curve of the mounting portion.

[0143] Furthermore, Rz3 represents the maximum height roughness of the surface of the insulator, with the width Wr of the region where the radiation electrode 7 is formed being the reference length of the cross-sectional curve of the insulator on which the mounting member 205 is mounted. Here, the "surface of the insulator" refers to the surface of the insulator that is in contact with the upper or lower surface of the radiation electrode 7.

[0144] The maximum height roughnesses Rz1, Rz2, and Rz3 are in the relationship of Rz1 < Rz2 < Rz3. Thus, the module substrate 305 has three surfaces with different roughnesses (concavities and convexities).

[0145] Signal line conductor patterns SLa, SLb and a ground conductor layer GL are formed inside the multilayer substrate 105. These signal line conductor patterns SLa, SLb, the ground conductor layer GL, and the resin layer therebetween form a microstrip transmission line.

[0146] A plurality of external electrodes 1 are exposed on the first surface S1 of the multilayer substrate 105. Pad electrodes 2 are formed on the second surface S2 of the multilayer substrate 105. Terminal electrodes 6 of the mounting component 205 are bonded to the pad electrodes 2. Furthermore, the resin surface of the mounting component 205 is bonded to the resin layer of the multilayer substrate 105.

[0147] The component-side land electrode 42 is connected to the external electrode 1 of the multilayer substrate 105 via the connection conductor BM. The connection conductor BM is, for example, a heated molten metal such as solder.

[0148] exist Figure 5In the example shown, the multilayer substrate 105 is bent (folded) by 90° along the XZ plane toward the mounting surface of the mounting component 205 .

[0149] The connector 25 is connected to the patch antenna formed by mounting the mounting member 205 .

[0150] According to this embodiment, the multi-layer substrate 105 is flexible, and therefore, a module substrate 305 having a predetermined shape can be configured as a whole.

[0151] Sixth Implementation Method

[0152] In the sixth embodiment, an example is shown in which the structure of the boundary portion between the multilayer substrate and the mounted component is different from that of the module substrate shown so far.

[0153] Figure 6 This is a cross-sectional view of a module substrate 306 according to the sixth embodiment. Module substrate 306 includes a multilayer substrate 106 and a mounting component 206. Multilayer substrate 106 includes multiple resin layers 11, 12, 13, 14, and 15, as well as conductor layers and interlayer connection conductors attached to specific resin layers among these multiple resin layers. A connection conductor BM is formed by coating in the openings of resin layer 15. Connection conductor BM is, for example, a heated molten metal such as solder. Multilayer substrate-side pad electrodes 2 are formed below connection conductor BM.

[0154] The radiation electrode 7 is formed on the upper surface of the mounting member 206 or in the vicinity of the upper surface, so that the mounting member 206 functions as a patch antenna or a part of a patch antenna. The radiation electrode 7 is formed along the upper surface of the mounting member 206.

[0155] Here, Rz1 represents the maximum height roughness of the mounting portion facing region of the first surface S1 of the multilayer substrate 106 , which is a region facing the mounting portion of the mounting component 206 , with the width Wm of the mounting portion facing region being the reference length of the cross-sectional curve of the mounting portion facing region.

[0156] Furthermore, Rz2 represents the maximum height roughness of the mounting portion on the second surface S2 of the multilayer substrate 106 , with the width Wm of the mounting portion of the mounting component 206 being the reference length of the cross-sectional curve of the mounting portion.

[0157] Furthermore, Rz3 represents the maximum height roughness of the surface of the insulator, with the width Wr of the region where the radiation electrode 7 is formed being the reference length of the cross-sectional curve of the insulator on which the mounting member 206 is mounted. Here, the "surface of the insulator" refers to the surface of the insulator that is in contact with the upper or lower surface of the radiation electrode 7.

[0158] The maximum height roughnesses Rz1, Rz2, and Rz3 are in the relationship of Rz1<Rz2<Rz3.

[0159] The boundary between the mounting component 206 and the multilayer substrate 106 (the base of the mounting component 206 ) is covered with the resin material 10 . Since the resin material 10 covers the second surface S2 of the multilayer substrate 106 , the base of the mounting component 206 is pressed into the multilayer substrate 106 .

[0160] The resin material 10 is, for example, epoxy resin, and is applied to the multilayer substrate 106 in a state where the mounting component 206 is mounted. The resin material 10 is preferably made of a material having a Young's modulus higher than that of the resin layer constituting the multilayer substrate 106.

[0161] The Young's modulus is determined by performing a nanoindentation test in accordance with JIS Z 2255 and ISO 14577. For example, it is determined from load-displacement data using a Micro nanoindenter manufactured by KLA.

[0162] The mounting portion of the mounting component 206 is rigid, while the other portions are flexible. Therefore, when an external force tending to bend the module substrate 306 is applied, stress tends to concentrate on the base of the mounting component 206 .

[0163] In the module substrate 306 of this embodiment, the bonding strength between the multilayer substrate 106 and the mounting component 206 is high, thereby preventing cracks and chips at the interface between the multilayer substrate 106 and the mounting component 206. Furthermore, the mounting component 206 has high rigidity relative to the multilayer substrate 106, thereby suppressing deformation of the mounting component 206, such as tilting. This, in turn, prevents deviations in the antenna's radiation direction (directivity).

[0164] It should be noted that in Figure 6 , the resin part 10 is shown as a separate member from the multilayer substrate 106 and the mounting component 206. However, the shape of the resin part 10 can also be formed based on the multilayer substrate 106 or the mounting component 206. Specifically, after the mounting component 206 is placed on the multilayer substrate 106, pressure is applied to the multilayer substrate 106 to press the mounting component 206, and heat is applied to the multilayer substrate 106. This causes the mounting component 206 to sink into the multilayer substrate 106, and the resin layer on the upper layer of the multilayer substrate 106 accumulates at the base of the mounting component 206, forming this accumulated portion into the resin part 10. Alternatively, the pressure and heat described above can be used to melt the base of the mounting component 206, thereby forming the resin part 10.

[0165] Seventh Implementation Method

[0166] In the seventh embodiment, an electronic device including a module substrate and another substrate is exemplified.

[0167] Figure 74 is a cross-sectional view of an electronic device 407 according to the seventh embodiment. The electronic device 407 includes another substrate 27, and a multilayer substrate 101 and a mounting component 201 mounted on the other substrate 27. Hatching is omitted in the illustration of the other substrate 27.

[0168] The structure of the module substrate 301 formed by the multi-layer substrate 101 and the mounting component 201 is the same as that in the first embodiment. Figure 1 The module substrate 301 shown is identical.

[0169] The external electrodes 1 are formed on the mounting surface (lower surface) of the module substrate 301 . The other substrate-side pad electrodes 41 are formed on the mounting surface (upper surface) of the other substrate 27 .

[0170] The external electrodes 1 of the multilayer substrate 101 are connected to other substrate-side pad electrodes 41 via the connection conductors BM. The connection conductors BM are, for example, heated molten metal such as solder.

[0171] The other substrate 27 is, for example, a rigid glass epoxy substrate.

[0172] According to this embodiment, the multilayer substrate 101 has high mountability on the highly flat mounting surface of the other substrate 27, so the module substrate 301 can be mounted with high precision on the other substrate 27. For example, the multilayer substrate 101 having the external electrodes 1 arranged in a dispersed manner can be easily mounted on the other substrate 27.

[0173] Eighth Implementation Method

[0174] In the eighth embodiment, an electronic device including a housing is exemplified.

[0175] An electronic device according to this embodiment includes any of the module substrates described in the first to sixth embodiments and a housing that houses the module substrate.

[0176] The housing that houses the module substrate has a size and shape that can house (embed) the module substrate.

[0177] Note that, in order not to impair the gain of the antenna, at least the portion of the housing near the antenna is made of a non-conductive or non-magnetic material.

[0178] While various embodiments of the present invention have been described so far, they are all examples and are not intended to limit the scope of the present invention. The embodiments of the present invention may be omitted, replaced, or modified in various ways without departing from the gist of the invention. Embodiments in which such omissions, replacements, or modifications have been made are included within the scope of the present invention, the gist of the present invention, and are also included within the inventions described in the claims of this application and their equivalents.

[0179] For example, the mounting component is a component that meets the electrical characteristics required for the antenna. Therefore, if a high dielectric constant is important for the mounting component's dielectric, a material with a higher dielectric constant than the resin layer of the multilayer substrate can be used. For example, a high dielectric constant ceramic material can be used. This allows for the production of an antenna module substrate with excellent electrical characteristics.

[0180] In addition, although the examples in which a protective film is formed on the multi-layer substrate, the mounted components, etc. are not shown in the respective embodiments, a protective film may be formed on a predetermined portion or the entire surface of the outer surface.

[0181] In each embodiment, the signal line conductor pattern SL and the ground conductor layer GL are formed to configure a microstrip line. However, the structure of the module substrate is not limited to a structure in which a transmission line is connected to a mounted component.

[0182] The multilayer substrate and electronic device of the present invention can also be provided in the following aspects.

[0183] <1>

[0184] A module substrate comprising:

[0185] a multilayer substrate having a plurality of resin layers and a conductor layer attached to a predetermined resin layer among the plurality of resin layers; and

[0186] a mounting component including an insulator and a radiation electrode formed on the insulator and mounted on the multilayer substrate;

[0187] The multilayer substrate has a first surface and a second surface forming a front-back relationship.

[0188] The multilayer substrate has external electrodes exposed on the first surface.

[0189] The multi-layer substrate has a mounting portion for mounting the component on a portion of the second surface of the multi-layer substrate.

[0190] The mounting component has a mounting surface in contact with the mounting portion of the multi-layer substrate.

[0191] The radiation electrode is formed on a surface separated from the mounting surface or in a region along the surface.

[0192] The resin layer at the mounting portion of the multilayer substrate is directly bonded to the insulator at the mounting surface of the mounting component.

[0193] When Rz1 represents the maximum height roughness of the mounting portion opposing region of the first surface of the multilayer substrate, with the width of the mounting portion opposing region being the reference length of the cross-sectional curve of the mounting portion opposing region; Rz2 represents the maximum height roughness of the mounting portion of the second surface of the multilayer substrate, with the width of the mounting portion being the reference length of the cross-sectional curve of the mounting portion; and Rz3 represents the maximum height roughness of the surface of the insulator, with the width of the radiation electrode formation region being the reference length of the cross-sectional curve of the insulator, the relationship Rz1<Rz2<Rz3 is satisfied.

[0194] <2>

[0195] In the module substrate described in <1>,

[0196] The resin layer of the multi-layer substrate and the insulator of the mounting component are made of the same material.

[0197] <3>

[0198] In the module substrate described in <1>,

[0199] The resin layer of the multi-layer substrate and the insulator of the mounting component are made of different materials.

[0200] <4>

[0201] In the module substrate described in any one of <1> to <3>,

[0202] The resin layer of the multi-layer substrate is a thermoplastic resin.

[0203] <5>

[0204] In the module substrate described in <4>,

[0205] The resin layer of the multi-layer substrate is a liquid crystal polymer resin.

[0206] <6>

[0207] In the module substrate described in any one of <1> to <5>,

[0208] The mounted component has terminal electrodes. An interlayer connection conductor mainly composed of Cu or Ag is formed on the first surface of the multilayer substrate, and the terminal electrodes of the mounted component are connected to the interlayer connection conductor.

[0209] <7>

[0210] In the module substrate described in any one of <1> to <6>,

[0211] A transmission line is formed on the multi-layer substrate.

[0212] <8>

[0213] In the module substrate described in any one of <1> to <7>,

[0214] The multi-layer substrate has a bent portion.

[0215] <9>

[0216] In the module substrate described in any one of <1> to <8>,

[0217] A component connected to the external electrode and mounted on the multi-layer substrate is provided.

[0218] <10>

[0219] In the module substrate described in any one of <1> to <9>,

[0220] A resin member is provided that covers a boundary between the mounting component and the multi-layer substrate (a base portion of the mounting component).

[0221] <11>

[0222] An electronic device comprising:

[0223] The module substrate according to any one of <1> to <10>; and

[0224] Another substrate on which the module substrate is mounted.

[0225] <12>

[0226] An electronic device comprising:

[0227] The module substrate according to any one of <1> to <10>; and

[0228] A housing that houses the module substrate.

Claims

1. A module substrate comprising: a multilayer substrate having a plurality of resin layers and a conductor layer attached to a predetermined resin layer among the plurality of resin layers; and a mounting component including an insulator and a radiation electrode formed on the insulator and mounted on the multilayer substrate; The multilayer substrate has a first surface and a second surface forming a front-back relationship. The multilayer substrate has external electrodes exposed on the first surface. The multi-layer substrate has a mounting portion for mounting the component on a portion of the second surface of the multi-layer substrate. The mounting component has a mounting surface in contact with the mounting portion of the multi-layer substrate. The radiation electrode is formed on a surface separated from the mounting surface or in a region along the surface. The resin layer at the mounting portion of the multilayer substrate is directly bonded to the insulator at the mounting surface of the mounting component. When Rz1 represents the maximum height roughness of the mounting portion opposing region of the first surface of the multilayer substrate, with the width of the mounting portion opposing region being the reference length of the cross-sectional curve of the mounting portion opposing region; Rz2 represents the maximum height roughness of the mounting portion of the second surface of the multilayer substrate, with the width of the mounting portion being the reference length of the cross-sectional curve of the mounting portion; and Rz3 represents the maximum height roughness of the surface of the insulator, with the width of the radiation electrode formation region being the reference length of the cross-sectional curve of the insulator, the relationship Rz1<Rz2<Rz3 is satisfied.

2. The module substrate according to claim 1, wherein: The resin layer of the multi-layer substrate and the insulator of the mounting component are made of the same material.

3. The module substrate according to claim 1, wherein: The resin layer of the multi-layer substrate and the insulator of the mounting component are made of different materials.

4. The module substrate according to any one of claims 1 to 3, wherein: The resin layer of the multi-layer substrate is a thermoplastic resin.

5. The module substrate according to claim 4, wherein: The resin layer of the multi-layer substrate is a liquid crystal polymer resin.

6. The module substrate according to any one of claims 1 to 5, wherein: The mounted component has terminal electrodes. An interlayer connection conductor mainly composed of Cu or Ag is formed on the first surface of the multilayer substrate, and the terminal electrodes of the mounted component are connected to the interlayer connection conductor.

7. The module substrate according to any one of claims 1 to 6, wherein: A transmission line is formed on the multi-layer substrate.

8. The module substrate according to any one of claims 1 to 7, wherein: The multi-layer substrate has a bent portion.

9. The module substrate according to any one of claims 1 to 8, wherein: The module substrate includes components connected to the external electrodes and mounted on the multi-layer substrate.

10. The module substrate according to any one of claims 1 to 9, wherein: The module substrate includes a resin member covering a boundary between the mounted component and the multilayer substrate.

11. An electronic device comprising: The module substrate according to any one of claims 1 to 10; and Another substrate on which the module substrate is mounted.

12. An electronic device comprising: The module substrate according to any one of claims 1 to 10; and A housing that houses the module substrate.

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