Multilayer substrate and electronic device

Abstract

Provided are a multilayer substrate and an electronic device provided with the multilayer substrate, the multilayer substrate being less likely to cause cracks and defects at locations where the number of stacked insulator layers differs. A multilayer substrate (101) is provided with a first substrate part (1), a second substrate part (2), and a raised part (3). The first substrate part (1) is formed of a first material. The second substrate section (2) is formed of a second material, and has a protruding section (EX) that is joined to the first substrate section (1) and protrudes from the first substrate section (1). The protruding part (3) is made of a first material, is bonded to the base part of the protruding part (EX) of the second substrate part (2), and protrudes near the base part of the protruding part (EX) to cover a part of the side part of the protruding part (EX).

Description

Technical Field

[0001] The present invention relates to a multi-layer substrate and an electronic device including the multi-layer substrate. Background Art

[0002] Patent Document 1 discloses a multilayer substrate including a plurality of insulating layers. In addition, the multilayer substrate discloses a multilayer substrate in which regions having different thicknesses in the stacking direction are locally formed due to differences in the number of stacked insulating layers.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2005-236873

[0006] The structure of locally forming regions of varying thickness in the stacking direction due to the number of stacked insulator layers with a conductive layer, allows for the thicker portions to function as a given electronic component. However, stress concentration on areas with varying numbers of stacked insulator layers can easily lead to cracks and defects. Summary of the Invention

[0007] Problems to be solved by the invention

[0008] Therefore, an object of the present invention is to provide a multilayer substrate in which cracks and defects are less likely to occur at locations where the number of laminated insulating layers differs, and to provide an electronic device including the multilayer substrate.

[0009] Technical solutions to solve problems

[0010] (1) A multilayer substrate as an example of the present disclosure includes:

[0011] a first substrate portion formed by laminating resin layers of a first material;

[0012] a second substrate portion having a protruding portion bonded to and protruding from the first substrate portion, and formed by laminating resin layers of a second material; and

[0013] a raised portion, which is joined to the base of the protruding portion of the second substrate portion, and is raised near the base of the protruding portion to cover a portion of the side of the protruding portion, and is made of the first material;

[0014] The bottom portion of the second substrate portion, which is a portion of a bonding surface of the second substrate portion with respect to the first substrate portion, is located below an upper surface of the first substrate portion.

[0015] (2) An electronic device as an example of the present disclosure is configured to include a multi-layer substrate and electronic components mounted on the multi-layer substrate.

[0016] Effects of the Invention

[0017] According to the present invention, a multilayer substrate can be obtained in which cracks and defects are less likely to occur at locations where the number of laminated insulating layers differs, and an electronic device including the multilayer substrate can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a cross-sectional view of the multi-layer substrate 101 according to the first embodiment.

[0019] Figure 2 It is a diagram showing in particular the shape of the raised portion 3 .

[0020] Figure 3 1 and 2 are diagrams showing the positional relationship between the first substrate portion 1 and the second substrate portion 2 .

[0021] Figure 4 It is a diagram showing the shape of the joining portion between the base portion of the second substrate portion 2 and the first substrate portion 1 .

[0022] Figure 5 This is a cross-sectional view of a mid-stage of manufacturing the multi-layer substrate 101 .

[0023] Figure 6 It is a cross-sectional view of another multilayer substrate 101A according to the first embodiment.

[0024] Figure 7 It is a cross-sectional view of a multi-layer substrate 102 according to the second embodiment.

[0025] Figure 8 is a top view of the multi-layer substrate 102 .

[0026] Figure 9 It is a cross-sectional view of a multi-layer substrate 103 according to the third embodiment.

[0027] Figure 10 It is a cross-sectional view of an electronic device 301 according to the fourth embodiment.

[0028] Description of Reference Numerals

[0029] BP…Bend

[0030] CA…Depression

[0031] CP…Pit

[0032] EX…Protrusion

[0033] FP…Flexible part

[0034] RP…Rigid part

[0035] S1... Upper surface of the first substrate

[0036] S12…Bottom of the second substrate

[0037] SS…Slant section

[0038] 1…1st substrate section

[0039] 1a, 1b...resin layer of the first substrate

[0040] 2...Second substrate section

[0041] 2a, 2b...resin layer of the second substrate

[0042] 2B…base of the protrusion

[0043] 2S…Side of the protrusion

[0044] 3… bulge

[0045] 4, 4S, 4G…conductor layer

[0046] 7…Radiating electrode

[0047] 8…Electronic components

[0048] 11, 12, 13, 14, 15, 16…resin layer

[0049] 101, 101A, 102, 103…Multilayer substrate

[0050] 301…Electronic equipment. DETAILED DESCRIPTION

[0051] Hereinafter, a plurality of methods for implementing the present invention will be illustrated with reference to the drawings and by enumerating several specific examples. In each figure, the same reference numeral is given to the same part. Taking into account the ease of explanation or understanding of the key points, the embodiment is divided into a plurality of embodiments for the sake of convenience of explanation, 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 brought about by the same structure are not mentioned one by one in each embodiment.

[0052] <First Implementation>

[0053] In the first embodiment, a multilayer substrate including a first substrate portion, a second substrate portion, and a raised portion is exemplified.

[0054] Figure 1 1 is a cross-sectional view of a multi-layer substrate 101 according to the first embodiment. Figure 1 The upper portion is a partial cross-sectional view of the multi-layer substrate 101. Figure 1 The lower portion is an enlarged view of the upper VP region. Furthermore, in the cross-sectional view, the lines appearing in the cross section (appearing by cutting) are depicted, and the lines existing behind the cross section are omitted from the illustration. This also applies to the various embodiments shown below.

[0055] like Figure 1 As shown in the upper portion of FIG, the multilayer substrate 101 includes a first substrate portion 1 and a second substrate portion 2 having a protruding portion EX protruding from the first substrate portion 1. When expressed along the XY plane, the portion where the second substrate portion 2 is present is a rigid portion RP, where the multilayer substrate has a large number of resin layers stacked together and thus has high rigidity, while the portion where the second substrate portion 2 is absent is a flexible portion FP.

[0056] The second substrate portion 2 includes a protruding portion EX that is bonded to the first substrate portion 1 and protrudes from the first substrate portion 1 . This can also be expressed as forming the protruding portion EX by the second substrate portion 2 .

[0057] In the first substrate portion 1 and the second substrate portion 2, a predetermined conductor layer is laminated together with the resin layer as needed. Figure 1 , the conductor layer 4 formed by patterning the Cu foil is shown.

[0058] The first substrate portion 1 is formed of a first material, and the second substrate portion 2 is formed of a second material. Figure 1 In FIG. 1 , the first substrate portion 1 and the second substrate portion 2 are displayed with hatching different from each other.

[0059] The first material has a lower Young's modulus than the second material. This allows the flexible portion FP to be bent while suppressing deformation of the rigid portion RP.

[0060] 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 nanoindentation apparatus manufactured by KLA.

[0061] The first and second materials can be, for example, the same material. This improves connection reliability. For example, if both are liquid crystal polymer (LCP) resins, a low-water-absorption resin like LCP can be used to produce a multilayer substrate with superior electrical properties and reliability.

[0062] Whether the resin materials are the same can be confirmed using Fourier transform infrared spectrophotometry (FT-IR). Specifically, a spectrum is obtained using FT-IR. If the peaks of the spectrum are the same for the second substrate portion 2 and the first substrate portion 1, it can be confirmed that they are made of the same resin material.

[0063] Furthermore, if the resin is a thermoplastic resin, the difference in melting point between the same type of resin material is small. Whether the resin portion of the first substrate portion 1 and the resin portion of the second substrate portion 2 are made of the same type of resin material can be confirmed using the endothermic peak of differential scanning calorimetry (DSC). Specifically, using a DSC8230 manufactured by Rigaku Corporation, the temperature can be raised at a rate of 10°C / minute. After cooling the molten material, the two resin materials can be considered to be of the same type if the difference in melting point when the temperature is raised again at 10°C / minute is within 5°C.

[0064] Figure 1 The first substrate portion 1 shown in the upper portion includes Figure 1 The second substrate portion 2 includes resin layers 2a and 2b.

[0065] exist Figure 1 In the figure shown in the lower part of the figure, the boundary surface of the different hatched parts (in Figure 1 Because it is a cross-sectional view, it is a boundary line), the first substrate portion 1 and the second substrate portion 2 are joined.

[0066] like Figure 1 As shown in the lower part of , the multilayer substrate 101 includes a raised portion 3. The raised portion 3 is bonded to a portion of the base portion 2B of the second substrate portion 2, and is raised near the base portion 2B to cover a portion of the side portion 2S of the second substrate portion 2.

[0067] In this way, due to the structure in which the first material of the first substrate part 1 is raised and joined to a part of the base 2B of the second substrate part 2, and is raised near the base 2B of the second substrate part 2 to cover a part of the side 2S of the second substrate part 2, the root of the second substrate part 2 is pressed into the main body of the first substrate part 1 by the raised part 3.

[0068] Generally, when a multilayer substrate is subjected to an external force that causes it to bend, stress tends to concentrate at the boundary between the rigid portion RP and the flexible portion FP (the portion where the number of laminated resin layers varies significantly). In the multilayer substrate 101 of this embodiment, the high bonding strength between the first substrate portion 1 and the second substrate portion 2 prevents cracking and damage at the interface between the first and second substrate portions 1 and 2. Furthermore, the high rigidity of the second substrate portion 2 relative to the first substrate portion 1 prevents deformation of the second substrate portion 2, such as tilting.

[0069] Figure 2 3 is a diagram showing in particular the shape of the raised portion 3. Figure 1 Similarly, the lower part of the Figure 2 yes Figure 1 The outer surface of the raised portion 3 is curved, forming a gently continuous surface from the upper surface of the first substrate portion 1 to the side surface of the second substrate portion 2. Figure 2 The arrow R in FIG. 1 shows the gently curved surface.

[0070] As previously mentioned, generally, when a multilayer substrate is subjected to an external force that causes it to bend, stress tends to concentrate on the portion where the number of resin layers stacked increases. In the multilayer substrate 101 of this embodiment, the periphery of the joining surface between the first substrate portion 1 and the second substrate portion 2 is a gently continuous curved surface, thereby alleviating the stress applied to the portion where the number of resin layers stacked increases. This prevents cracks and defects at the interface between the first substrate portion 1 and the second substrate portion 2, and because the second substrate portion 2 has a high rigidity relative to the first substrate portion 1, deformation such as tilting of the second substrate portion 2 can be suppressed.

[0071] Figure 3 1 is a diagram showing the positional relationship between the first substrate portion 1 and the second substrate portion 2. Figure 3 In FIG. 1 , S12 represents the bottom of the second substrate portion 2 as a part of the bonding surface of the second substrate portion 2 relative to the first substrate portion 1, and S1 represents the upper surface of the first substrate portion 1. Figure 3 The plane parallel to the XY plane is represented.

[0072] like Figure 3 As shown, the bottom S12 of the second substrate portion 2 is located below the upper surface S1 of the first substrate portion 1 along the Z axis. This structure facilitates the first material of the first substrate portion 1 to bulge near the base 2B of the second substrate portion 2, resulting in a significantly raised portion 3. This facilitates increased bonding strength between the first and second substrate portions 1 and 2.

[0073] Figure 4 : This is a diagram showing the shape of the joint between the base 2B of the second substrate 2 and the first substrate 1. The boundary between the side 2S of the second substrate 2 and the raised portion 3 has a slope SS where the width of the side 2S of the second substrate 2 becomes wider from the top of the raised portion 3 to the bottom. Figure 4 The two-dot chain line shown in shows the inclination angle of the inclined portion SS.

[0074] Thus, from the top of the raised portion 3 downward, the inclination angle of the inclined portion SS tilts from the Z-axis direction toward the direction in which the width of the side portion 2S of the second substrate portion 2 increases. This structure facilitates increasing the amount of the first material of the first substrate portion 1 covering the vicinity of the base portion 2B of the second substrate portion 2. This facilitates improving the bonding strength between the first substrate portion 1 and the second substrate portion 2.

[0075] As previously mentioned, when a multi-layer substrate is bent, stress is generally concentrated on the portion where the number of resin layers stacked increases. In the multi-layer substrate 101 of this embodiment, since the holding force used to hold the second substrate portion 2 toward the main body of the first substrate portion 1 by the first material is high, cracking and damage at the interface between the first substrate portion 1 and the second substrate portion 2 can be prevented.

[0076] Figure 5 This is a cross-sectional view of a mid-stage of manufacturing the multi-layer substrate 101 . Figure 5 The upper portion of FIG. 1 shows a state in which the second substrate portion 2 is laminated on the first substrate portion 1 and thermocompression-bonded by, for example, isostatic pressing during the manufacture of multilayer substrate 101. At this stage, the first substrate portion 1 is a laminated substrate comprising multiple resin layers and conductor layers, and has a recessed portion CP at a predetermined position on its upper portion. The second substrate portion 2 is a single-piece laminated substrate comprising multiple resin layers and conductor layers.

[0077] The recessed portion CP of the first substrate portion 1 is a mounting region for the second substrate portion 2. When viewed in the Z-axis direction, the area of ​​the recessed portion CP of the first substrate portion 1 is slightly larger than the area of ​​the junction between the first and second substrate portions 1 and 2.

[0078] exist Figure 5 In the upper portion of , the downward arrow indicates heating and pressurizing. When the first substrate portion 1 is made of a thermoplastic resin, the first material flows into the concave portion CP of the first substrate portion 1, which is the mounting destination of the second substrate portion 2, by thermocompression bonding, and the second substrate portion 2 is embedded in the first substrate portion 1.

[0079] exist Figure 5 In the lower part of , the arrows indicate the flow of the resin of the first material of the first substrate portion 1. The resin layer of the first substrate portion 1 is relatively raised relative to the second substrate portion 2, and the upper portion of the first substrate portion 1 is pressed toward the side of the second substrate portion 2 along the direction of the XY plane. Figures 1 to 4 The structure of the first substrate portion 1, the second substrate portion 2 and the raised portion 3 is shown.

[0080] Figure 6 1 is a cross-sectional view of another multilayer substrate 101A according to the first embodiment. Figure 6 The upper portion is a partial cross-sectional view of the multi-layer substrate 101A. Figure 6The lower part is an enlarged view of the VP area in the upper part.

[0081] exist Figures 1 to 5 In the example shown, the first material constituting the first substrate portion 1 and the second material constituting the second substrate portion 2 are both, for example, liquid crystal polymer resin (LCP), but they are not of the same composition. Figure 6 In the illustrated multilayer substrate 101A, the first material constituting the first substrate portion and the second material constituting the second substrate portion 2 are the same material, for example, liquid crystal polymer resin (LCP) having the same composition.

[0082] In addition to liquid crystal polymer resin (LCP), polyimide used in flexible substrates can also be used. For example, the first substrate portion 1 can be made of a highly flexible liquid crystal polymer resin (LCP) as the first material, while the second substrate portion 2 can be made of a highly rigid epoxy substrate containing a glass base, such as that used in printed circuit boards.

[0083] If the second material of the second substrate portion 2 is the same material as the first material of the first substrate portion, high adhesive strength can be obtained between the first substrate portion 1 and the second substrate portion 2 .

[0084] Second Implementation Method

[0085] In the second embodiment, a multilayer substrate 102 is exemplified showing the internal and surface structures.

[0086] Figure 7 It is a cross-sectional view of a multi-layer substrate 102 according to the second embodiment. Figure 8 1 is a plan view of the multi-layer substrate 102. In this example, a first substrate portion 1 having a rectangular planar shape is provided with a rectangular recessed portion CA, and a second substrate portion 2 is provided within the recessed portion CA.

[0087] The first substrate portion 1 includes: a plurality of resin layers 11, 12, 13, 14, 15, and 16; Cu foil applied to one side of each of these resin layers 11, 12, 13, 14, 15, and 16; and interlayer connection conductors formed within the resin layers 11, 12, 13, 15, and 16. These interlayer connection conductors are made of Cu or Ag and are formed by plating, for example.

[0088] In this example, the resin layers 11 , 12 , 13 , 14 , 15 , and 16 are thermoplastic resins such as liquid crystal polymer (LCP) resins, and are stacked by bonding adjacent resin layers in the stacking direction and bonding adjacent resin layers and Cu foils in the stacking direction.

[0089] Inside the first substrate portion 1, a signal line pattern is formed by a conductor layer 4S made of Cu foil, and a ground conductor layer is formed by a conductor layer 4G also made of Cu foil. These conductor layers 4S and 4G, along with the resin layers 11, 12, and 13 therebetween, form a microstrip transmission line. Forming the transmission line on the first substrate portion 1 in this way allows for a rigid / flexible substrate that integrates the circuit connected to the second substrate portion 2 with the transmission line, thus saving overall space.

[0090] The resin layer 16 has an opening, and the resin layers 11 , 12 , 13 , 14 , 15 , and 16 and the Cu foil are stacked, thereby forming a recessed portion (cavity) CA in a portion of the surface of the stacked body.

[0091] At the interface between the bottom surface of the recessed portion (cavity) CA and the bottom surface of the second substrate portion 2, a raised portion 3 is formed around the bottom surface of the second substrate portion 2. The height of the raised portion 3 in the Z direction is lower than the depth of the recessed portion CA.

[0092] Figure 5 The concave portion CP shown in the upper portion is the mounting area of ​​the second substrate portion 2, and is a concave portion formed in the first substrate portion 1 that is slightly wider than the outer shape of the second substrate portion 2. Figure 7 The recessed portion (cavity) CA shown is a recessed hole formed in the first substrate portion 1 and is wider than the outer shape of the second substrate portion 2 .

[0093] By laminating the second substrate portion 2 within the recessed portion CA of the first substrate portion 1, the height of the raised portion 3 is contained within the depth of the recessed portion CA. Consequently, the protrusion of the raised portion 3 does not adversely affect other components. For example, even if other components are located on the upper surface of the first substrate portion 1, these components and the raised portion 3 will not come into contact, maintaining the overall compactness.

[0094] like Figure 8 As shown, a radiation electrode 7 is formed on the upper surface of the second substrate portion 2 , and functions as a patch antenna together with a ground conductor layer formed near the lower surface of the second substrate portion 2 or the Cu foil of the first substrate portion 1 serving as the ground conductor layer.

[0095] The second material used as the material for the second substrate portion 2 has a higher dielectric constant than the first material used as the material for the first substrate portion. This allows the high dielectric constant of the second substrate portion to be effectively utilized. For example, in this embodiment, the patch antenna can be miniaturized. Furthermore, the proportion of the rigid portion in the multilayer substrate can be reduced.

[0096] According to this embodiment, since the second substrate 2 has high rigidity relative to the first substrate 1, deformation such as tilting of the second substrate 2 can be suppressed. This can suppress deviations in the radiation direction (directivity) of the antenna.

[0097] <<Third Implementation Method>>

[0098] In the third embodiment, a multilayer substrate having a bent portion in a first substrate portion is exemplified.

[0099] Figure 9 is a cross-sectional view of a multilayer substrate 103 according to the third embodiment. Figure 7 The structure is similar to that of the multi-layer substrate 102. Since the first substrate portion 1 is flexible, it can be bent at any position.

[0100] exist Figure 9 In the example shown, the bent portion BP of the first substrate portion 1 is bent 90° at a predetermined curvature. Thus, even when the first substrate portion 1 is bent, the presence of the raised portion 3 can suppress stress applied to the periphery of the interface between the first substrate portion 1 and the second substrate portion 2.

[0101] Furthermore, deformation of the rigid portion RP can be suppressed by bending the flexible portion FP, and thus the functional characteristics of the electronic component formed by the rigid portion RP can be stably maintained.

[0102] <<Fourth Implementation>>

[0103] In the fourth embodiment, an electronic device according to the present invention is exemplified.

[0104] Figure 10 3 is a cross-sectional view of an electronic device 301 according to a fourth embodiment. The electronic device according to the present invention includes the multi-layer substrate according to the present invention and electronic components mounted on the multi-layer substrate.

[0105] exist Figure 10 In the illustrated example, electronic components 8 are mounted on the first substrate portion 1. Examples of the electronic components 8 include chip capacitors for impedance matching of a signal transmission line connected to the radiation electrode 7, a power amplifier IC for outputting a transmission signal to the radiation electrode 7, and a signal amplifier IC for amplifying a signal received by the radiation electrode 7.

[0106] So far, various embodiments of the present invention have been described, but these are all examples and are not intended to limit the scope of the present invention. The embodiments of the present invention can 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 included within the invention described in the claims of this application and their equivalents.

[0107] For example, in the second and fourth embodiments, examples in which the patch antenna is formed on the second substrate portion 2 are shown, but the present invention is also applicable to a multilayer substrate in which other circuits are formed on the second substrate portion 2 .

[0108] The multilayer substrate and electronic device of the present invention can also be provided in the various aspects described below.

[0109] <1>

[0110] A multi-layer substrate comprising:

[0111] a first substrate portion formed by laminating resin layers of a first material;

[0112] a second substrate portion having a protruding portion bonded to and protruding from the first substrate portion, and formed by laminating resin layers of a second material; and

[0113] a raised portion, which is joined to the base of the protruding portion of the second substrate portion, and is raised near the base of the protruding portion to cover a portion of the side of the protruding portion, and is made of the first material;

[0114] The bottom portion of the second substrate portion, which is a portion of a bonding surface of the second substrate portion with respect to the first substrate portion, is located below an upper surface of the first substrate portion.

[0115] <2>

[0116] exist <1> In the multi-layer substrate described,

[0117] The boundary between the side portion of the second substrate portion and the raised portion has an inclined portion in which the width of the side portion of the second substrate portion increases from the top of the raised portion to the bottom.

[0118] <3>

[0119] exist <1> or <2> In the multi-layer substrate described,

[0120] The first material and the second material are the same material.

[0121] <4>

[0122] exist <1> to <3> In the multilayer substrate described in any one of

[0123] The second material has a higher dielectric constant than the first material.

[0124] <5>

[0125] exist <1> to <4> In the multilayer substrate described in any one of

[0126] The first material and the second material are thermoplastic resins.

[0127] <6>

[0128] exist <5> In the multi-layer substrate described,

[0129] The thermoplastic resin is a liquid crystal polymer resin.

[0130] <7>

[0131] exist <1> to <6> In the multilayer substrate described in any one of

[0132] The first material has a lower Young's modulus than the second material.

[0133] <8>

[0134] exist <1> to <7> In the multilayer substrate described in any one of

[0135] The first substrate portion has a recessed portion recessed from the upper surface of the first substrate portion, the second substrate portion is joined to the bottom of the recessed portion of the first substrate portion, the raised portion is located in the recessed portion, and a portion of the second substrate portion protrudes from the upper surface of the first substrate portion.

[0136] <9>

[0137] exist <1> to <8> In the multilayer substrate described in any one of

[0138] An antenna is formed on the second substrate portion.

[0139] <10>

[0140] exist <1> to <9> In the multilayer substrate described in any one of

[0141] A transmission line is formed on the first substrate portion.

[0142] <11>

[0143] exist <1> to <10> In the multilayer substrate described in any one of

[0144] The first substrate portion has a bent portion.

[0145] <12>

[0146] An electronic device comprising <1> to <11> A multilayer substrate as described in any one of the items and an electronic component mounted on the multilayer substrate.

Claims

1. A multi-layer substrate comprising: a first substrate portion formed by laminating resin layers of a first material; a second substrate portion having a protruding portion bonded to and protruding from the first substrate portion, and formed by laminating resin layers of a second material; and a raised portion, which is joined to the base of the protruding portion of the second substrate portion, and is raised near the base of the protruding portion to cover a portion of the side of the protruding portion, and is made of the first material; The bottom portion of the second substrate portion, which is a portion of a bonding surface of the second substrate portion with respect to the first substrate portion, is located below an upper surface of the first substrate portion.

2. The multi-layer substrate according to claim 1, wherein The boundary between the side portion of the second substrate portion and the raised portion has an inclined portion in which the width of the side portion of the second substrate portion increases from the top of the raised portion to the bottom.

3. The multi-layer substrate according to claim 1 or 2, wherein The first material and the second material are the same material.

4. The multi-layer substrate according to any one of claims 1 to 3, wherein The second material has a higher dielectric constant than the first material.

5. The multi-layer substrate according to any one of claims 1 to 4, wherein The first material and the second material are thermoplastic resins. The multi-layer substrate according to claim 5 , wherein: The thermoplastic resin is a liquid crystal polymer resin.

7. The multi-layer substrate according to any one of claims 1 to 6, wherein The first material has a lower Young's modulus than the second material.

8. The multi-layer substrate according to any one of claims 1 to 7, wherein The first substrate portion has a recessed portion recessed from the upper surface of the first substrate portion, the second substrate portion is joined to the bottom of the recessed portion of the first substrate portion, the raised portion is located in the recessed portion, and a portion of the second substrate portion protrudes from the upper surface of the first substrate portion.

9. The multi-layer substrate according to any one of claims 1 to 8, wherein An antenna is formed on the second substrate portion.

10. The multi-layer substrate according to any one of claims 1 to 9, wherein A transmission line is formed on the first substrate portion.

11. The multi-layer substrate according to any one of claims 1 to 10, wherein The first substrate portion has a bent portion. 12 . An electronic device comprising the multi-layer substrate according to claim 1 and an electronic component mounted on the multi-layer substrate.

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