Wiring board and electronic module provided with same

Abstract

This invention improves heat dissipation of a wiring board while reducing the possibility of breakage of the wiring board. A side surface of this wiring board has a main side surface positioned in a central portion in the thickness direction, and an inclined surface. The inclined surface has a first portion and a second portion from a first surface side having a mounting region, the first portion and the second portion have differing surface shapes, and the second portion has a plurality of protrusions.

Description

Wiring board and electronic module including same

[0001] The present disclosure relates to a wiring board and an electronic module including the same.

[0002] 2. Description of the Related Art Wiring boards for mounting electronic components, which are made up of a plurality of ceramic layers, are known.

[0003] Japanese Patent Application Publication No. 2009-170499

[0004] A wiring board according to one aspect of the present disclosure comprises an insulating substrate having a first surface and a plurality of side surfaces connected to the first surface, at least one of the side surfaces having a main side surface, at least a portion of which is located in a central portion in a thickness direction of the side surface and having a surface parallel to the thickness direction, and an inclined surface connecting the first surface and the main side surface, the inclined surface having a first portion connected to the first surface and a second portion located between the first portion and the main side surface, the first portion and the second portion having different surface shapes, and the second portion having a plurality of protrusions.

[0005] 1 is a perspective view of an electronic module according to an embodiment of the present disclosure; FIG. 2 is a partially enlarged view of a motherboard; FIG. 3 is an enlarged view of region P shown in FIG. 1; FIG. 4 is a micrograph of region Q shown in FIG. 3; FIG. 5 is a side view of the wiring board of FIG. 3 when viewed from the negative direction of the X-axis; FIG. 6 is a micrograph of region R shown in FIG. 5 taken from the negative direction of the X-axis; FIG. 7 is a micrograph of region R shown in FIG. 5 taken from an obliquely upward direction relative to the wiring board; FIG. 8 is a micrograph showing the surface shape of a first portion according to an embodiment of the present disclosure; FIG. 9 is a micrograph showing the surface shape of a second portion according to an embodiment of the present disclosure; FIG. 10 is a micrograph taken from an obliquely upward direction of a motherboard; FIG. 11 is a cross-sectional view taken along line IX-IX shown in FIG. 3; FIG. 12 is a cross-sectional view taken along line X-X shown in FIG. 3; FIG. 13 is an enlarged perspective view of a wiring board according to another embodiment of the present disclosure; FIG. 14 is a plan view of a wiring board according to another embodiment of the present disclosure.

[0006] In wiring boards, there is a demand for improved quality of wiring boards.

[0007] According to one aspect of the present disclosure, it is possible to improve the heat dissipation performance of a wiring board while reducing the possibility of the wiring board being damaged.

[0008] [Embodiments] A wiring board and an electronic module according to embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0009] The distinction between top and bottom in the following description is for convenience and does not limit the top and bottom when the wiring board and electronic module are actually used. In this specification, the surface of the wiring board on which electronic components are mounted is defined as the top surface. In the drawings, the positive direction of the Z axis is the upward direction. The X axis is the minor axis direction of the wiring board, and the Y axis is an axis that perpendicularly intersects with the X axis and Z axis. The Z axis is the thickness direction of the wiring board.

[0010] 1 is a perspective view of an exemplary electronic module 700 of the present disclosure. As shown in FIG. 1 , the electronic module 700 includes a wiring substrate 500 and an electronic component 600. The wiring substrate 500 includes an insulating substrate 100 and a wiring conductor 300.

[0011] In FIG. 1 , the outline of the electronic component 600 is indicated by a dashed line. The electronic component 600 may be mounted by being bonded to the first surface 120 using a bonding material such as brazing material, glass, or adhesive, or may be indirectly mounted on the first surface 120 via a member such as a base. The electronic component 600 may be a semiconductor element, a piezoelectric element, a sensor element, or a passive element, such as a charge-coupled device (CCD) element or a complementary metal-oxide semiconductor (CMOS) element. Alternatively, the electronic component 600 may be a display element such as a liquid crystal display. While FIG. 1 shows an example in which one electronic component 600 is mounted on the wiring substrate 500, the electronic module 700 may be mounted with multiple types of electronic components 600.

[0012] The insulating substrate 100 of the wiring substrate 500 may be, for example, a flat insulator having a rectangular shape in a plan view. The insulating substrate 100 shown in FIG. 1 has a first surface 120, a second surface 130 located opposite the first surface 120, four side surfaces 140, and corners 150.

[0013] First surface 120 may include a mounting area on which electronic component 600 is mounted. Mounting area 180 on first surface 120 may be an area that overlaps with electronic component 600 when wiring substrate 500 is viewed in plan. Furthermore, first surface 120 may have a plurality of connection electrodes 310 positioned thereon that are electrically connected to electrodes of electronic component 600. Connection electrodes 310 may be electrically connected to electrodes of electronic component 600 via a conductive bonding material such as bonding wire or solder.

[0014] The connection electrode 310 may be a part of the wiring conductor 300 included in the wiring substrate 500. As shown in FIG. 3 , the wiring conductor 300 included in the wiring substrate 500 may include, in addition to the connection electrode 310, internal wiring 320 located inside the insulating substrate 100 and extending in a direction parallel to the first surface 120. The wiring conductor 300 may also include a via conductor extending in the thickness direction of the insulating substrate 100. The wiring conductor 300 may further include an external terminal electrode located on the second surface 130 and electrically connected to an electrode of an external device. The connection electrode 310 may be electrically connected to the external terminal electrode via the via conductor and / or the internal wiring 320.

[0015] The side surface 140 may be a surface that connects the first surface 120 and the second surface 130. The corner portion 150 may be a portion located between two side surfaces 140. As shown in FIG. 1 , the corner portion 150 may be chamfered. In other words, the corner portion 150 located between two side surfaces 140 may have a surface that connects the two side surfaces 140. By chamfering the corner portion 150, the possibility of chipping occurring at the corner portion 150 of the insulating substrate 100 can be reduced.

[0016] The insulating substrate 100 may be made of ceramics such as an aluminum oxide sintered body (alumina ceramics), an aluminum nitride sintered body, a mullite sintered body, or a glass ceramic sintered body. The insulating substrate 100 may include a plurality of laminated insulating layers.

[0017] The wiring substrate 500 may be a substrate formed by cutting a mother substrate along a dividing groove. Specifically, the wiring substrate 500 may be manufactured, for example, by preparing a mother substrate and dividing the mother substrate into individual pieces. The mother substrate can also be referred to as a multi-piece substrate. FIG. 2 is an enlarged view of a portion of the mother substrate before division where two wiring substrate regions 500B are adjacent. The mother substrate has multiple wiring substrate regions 500B arranged vertically and horizontally on the substrate surface. The wiring substrate regions 500B are regions that will be divided into individual wiring substrates 500. The mother substrate has a dividing groove G at the boundary between two adjacent wiring substrate regions 500B, and the individual wiring substrates 500 are obtained by breaking the mother substrate along the dividing groove G. The two wiring substrate regions 500B do not necessarily have to be adjacent to each other. For example, a portion that is not used as part of the wiring substrate 500 (hereinafter referred to as a dummy region) may be formed between two wiring substrate regions 500B, and the wiring substrate regions 500B may be arranged side by side with the dummy region sandwiched between them. In other words, a dummy region may be located between each of the wiring substrate regions 500B on the mother substrate.

[0018] The division grooves G can be formed, for example, by using a laser to partially remove the mother substrate before or after firing. Examples of lasers used to form the division grooves G include a carbon dioxide laser, a fiber laser, a YAG (Yttrium-Aluminum-Garnet) laser, a femtosecond laser, and a picosecond laser. A femtosecond laser or a picosecond laser removes the target material by severing interatomic bonds with photons. Therefore, when a femtosecond laser or a picosecond laser is used to form the division grooves, the thermal impact on the wiring substrate 500 can be reduced compared to when a fiber laser or the like is used to form the division grooves G in the mother substrate.

[0019] FIG. 3 is an enlarged view of region P in FIG. 1 . As shown in FIG. 3 , side surface 140 of wiring substrate 500 has a main side surface 143 located in the center of the thickness direction (Z direction) of side surface 140 and parallel to the thickness direction, and an inclined surface 140B connecting first surface 120 and main side surface 143. In addition, inclined surface 140B has a first portion 141 connected to first surface 120 and a second portion 142 located between first portion 141 and main side surface 143. In this specification, “parallel” does not necessarily mean strictly parallel, but may mean approximately parallel. For example, main side surface 143 may be slightly inclined (up to about ±5°) with respect to the Z axis. Furthermore, if main side surface 143 is not strictly flat, it is sufficient that it is primarily parallel to the Z axis.

[0020] Side surface 140 of wiring substrate 500 may further have an inclined surface 140C on the second surface 130 side that connects second surface 130 and main side surface 143. In other words, wiring substrate 500 may have main side surface 143 located in the center of side surface 140 in the thickness direction, and inclined surfaces 140B and 140C located closer to first surface 120 and second surface 130, respectively, than main side surface 143.

[0021] When wiring substrate 500 is a substrate produced by dividing a mother substrate, inclined surfaces 140B and 140C may be surfaces corresponding to the surfaces (inner surfaces) of division grooves G in the mother substrate. Furthermore, main side surface 143 may be a portion corresponding to a fracture surface formed by breaking the mother substrate when the mother substrate is divided.

[0022] The structure of the side surface 140 of the wiring substrate 500 will be described in more detail below with reference to FIGS.

[0023] FIG. 4 is a micrograph of region Q shown in FIG. 3 . FIG. 5 is a side view of the wiring substrate of FIG. 3 when viewed from the negative direction of the X-axis. FIG. 6 is a micrograph of region R shown in FIG. 5 when photographed from the negative direction of the X-axis. FIG. 7 is a micrograph of region R shown in FIG. 5 when photographed from diagonally above the wiring substrate 500. FIG. 8 is a micrograph showing the surface shape of the first portion 141. FIG. 9 is a micrograph showing the surface shape of the second portion 142. FIGS. 8 and 9 are photographed at the same scale. FIG. 10 is a micrograph of the mother substrate before the wiring substrate 500 is singulated, photographed from diagonally above the mother substrate. FIG. 11 is a cross-sectional view of FIG. 3 taken along line IX-IX, perpendicular to the first surface. FIG. 12 is an end view of FIG. 3 taken along line X-X, perpendicular to the first portion 141. 11 and 12 are schematic diagrams for explaining the shape, and are not necessarily drawn to scale.

[0024] 4 to 12, the inclined surface 140B has a first portion 141 and a second portion 142 that have different surface shapes. The difference in the surface shapes of the first portion 141 and the second portion 142 will be described in detail below.

[0025] As shown in FIGS. 6 , 7 , and 9 , the second portion 142 has a plurality of protruding portions 142P. The protruding portions 142P may extend in a direction along the first surface 120. The protruding portions 142P extending along the first surface 120 may not be linear but may have a wavy shape. In other words, the protruding portions 142P may be wavy, and the distance from the first surface 120 may vary. The plurality of protruding portions 142P extending along the first surface 120 may be located at different heights on the wiring substrate 500. Due to the plurality of protruding portions 142P located at different heights on the wiring substrate 500 and extending along the first surface 120, the surface of the second portion 142 may have a stepped shape, as shown in FIGS. 5 and 11 .

[0026] The distance D6 between the multiple protrusions 142P may be 1 μm or more and 20 μm or less. As shown in Figure 11 , the distance D6 between the protrusions 142P in this specification may be the distance between the tips of the protrusions 142P when viewed in a direction perpendicular to the main side surface 143 (Y direction). The distance D6 may increase as the distance from the first surface 120 increases, as shown in Figures 6, 7, 11, etc.

[0027] The second portion 142 has multiple protrusions 142P, which increases the surface area of ​​the second portion 142. This may improve the heat dissipation of the wiring substrate 500. Furthermore, the protrusions 142P extend along the first surface 120, reducing the likelihood that the bonding material bonding the electronic component 600 to the wiring substrate 500 will reach the main side surface 143 if it flows from the first surface 120 toward the side surface 140. This reduces the likelihood that the external dimensions of the wiring substrate 500 will be changed by the bonding material. The effect of limiting the movement of the bonding material is more easily achieved when the distance D6 between the protrusions 142P increases with increasing distance from the first surface 120. Furthermore, the effects of improving heat dissipation and limiting the movement of the bonding material are more easily achieved when the distance D6 between the protrusions 142P is 1 μm or more and 20 μm or less.

[0028] Furthermore, the second portion 142 may have a melted and re-solidified layer. The melted and re-solidified layer is a layer formed by cooling and re-solidifying ceramic that has been melted by laser irradiation. As shown in Figures 8 and 9, the second portion 142 has a melted and re-solidified layer, making the surface of the second portion 142 smoother than that of the first portion 141. As a result, when the insulating substrate 100 is made of a ceramic material, the second portion 142 is melted and re-solidified, which reduces the possibility of the ceramic material on the surface of the insulating substrate 100 peeling off.

[0029] Unlike the second portion 142 described above, the first portion 141 does not have a convex portion 142P extending at least in a direction along the first surface 120. That is, the portion of the inclined surface 140B without the convex portion 142P may be defined as the first portion 141, and the portion with the convex portion 142P may be defined as the second portion 142. As shown in FIGS. 7, 10, and 12, the first portion 141 may have a plurality of grooves 141C extending in a direction from the first surface 120 toward the second portion 142. The unevenness of the surface of the first portion 141 formed by the grooves 141C may be finer than the unevenness of the surface of the second portion 142 formed by the convex portions 142P in the second portion 142. Specifically, the spacing between adjacent grooves 141C may be smaller than the spacing between adjacent convex portions 142P. The spacing between the grooves 141C may be the center-to-center distance in the width direction of each groove 141C.

[0030] The first portion 141 may be provided with a plurality of grooves 141C, thereby further improving the heat dissipation properties of the wiring substrate 500.

[0031] In this way, the first portion 141 and the second portion 142 have different surface shapes. Such different surface shapes can be obtained by changing the laser irradiation conditions for the portion corresponding to the first portion 141 and the portion corresponding to the second portion 142 when forming the division groove G by laser in the mother substrate state.

[0032] Furthermore, as shown in FIG. 10 , the first portion 141 may have a convex curved surface. A convex curved surface refers to a portion of the wiring substrate 500 that has a convex surface shape in a direction away from the center of the wiring substrate 500. The first portion 141 may have a convex curved surface at least in part. Alternatively, the surface of the first portion 141 may be a curved surface that is entirely convex with respect to the wiring substrate 500. In other words, the entire surface of the first portion 141 may be a convex curved surface. The curvature of the curved surface does not need to be constant in the height direction of the wiring substrate 500, and may increase as it approaches the first surface 120. Having the convex curved surface in the first portion 141 can smooth the corners between the first surface 120 and the side surface 140 of the wiring substrate 500. This reduces the possibility of chipping the wiring substrate 500 if the wiring substrate 500 collides with another component, for example, during the mounting of the electronic component 600.

[0033] As described above, wiring substrate 500 has main side surface 143 and inclined surface 140B. Inclined surface 140B has first portion 141 connected to first surface 120 and second portion 142 located between first portion 141 and main side surface 143, and has a different surface shape from first portion 141 and second portion 142. Second portion 142 also has a plurality of protrusions 142P. This configuration can improve the heat dissipation performance of wiring substrate 500 while reducing the possibility of damage to wiring substrate 500.

[0034] Next, the main side surface 143 will be described in detail. In FIG. 4 , the boundary of the main side surface 143 near the corner 150 is illustrated by a dashed line. As shown in FIG. 4 , the dimension of the main side surface 143 in the thickness direction of the insulating substrate 100 may decrease toward the corner 150. In other words, the main side surface 143 has a rounded shape toward the corner 150. This configuration reduces the length of the sharp corner at the boundary between the corner 150 and the main side surface 143, thereby reducing the possibility of chipping of the wiring board 500 when the wiring board 500 collides with another component, for example, during mounting of the electronic component 600. The main side surface 143 may or may not be connected to the corner 150. When the main side surface 143 is not connected to the corner 150, the second portion 142 may be located between the corner 150 and the main side surface 143.

[0035] Furthermore, the surface roughness of the main side surface 143 may be greater than the surface roughness of the first portion 141. In other words, the surface roughness of the first portion 141 may be smaller than the surface roughness of the main side surface 143. The surface roughness in the present disclosure may be the arithmetic mean roughness Ra, which may be measured, for example, by an AFM (Atomic Force Microscope). By reducing the surface roughness of the first portion 141, corners connecting to the first surface 120 of the wiring substrate 500 are smoothed, thereby reducing the possibility of chipping in the wiring substrate 500. Furthermore, by increasing the surface roughness of the main side surface 143, heat can be efficiently dissipated from the main side surface 143 as well.

[0036] 3 and 4, an end portion of the internal wiring 320 may be exposed at the main side surface 143. By exposing a portion of the internal wiring 320 on the surface of the wiring substrate 500, the heat dissipation properties of the wiring substrate 500 may be further improved.

[0037] As shown in FIG. 5 , the inclination F1 of the first portion 141 relative to the main side surface 143 may be greater than the inclination F2 of the second portion 142 relative to the main side surface 143. As described above, the inclined surface 140B including the first portion 141 and the second portion 142 may correspond to the dividing groove G formed in the mother substrate. When the inclination F1 of the first portion 141 relative to the main side surface 143 is greater than the inclination F2 of the second portion 142 relative to the main side surface 143, the groove formed by adjacent second portions 142 has a sharper angle. This makes it easier to break the mother substrate. This improves the quality of the wiring substrate 500. More specifically, the inclination of the main side surface 143 relative to the first surface 120 and / or the second surface 130 can be closer to 90°.

[0038] 5 , the inclination F1 of the first portion 141 relative to the main side surface 143 may be greater than the inclination F2 of the second portion 142 relative to the main side surface 143, and the dimension D1 of the first portion 141 may be greater than the dimension D2 of the second portion 142 in the Z-axis direction. This configuration allows the motherboard to be broken more easily, thereby improving the quality of the wiring substrate 500. When the thickness of the wiring substrate 500 is small, the dimension D1 of the first portion 141 may be smaller than the dimension D2 of the second portion 142. When the thickness of the wiring substrate 500 is small, the dimension T in the Z-axis direction from the first surface 120 to the second surface 130 may be 0.4 mm or less, for example.

[0039] Furthermore, as shown in FIG. 5 , the dimension D12, which is the sum of the dimension D1 of the first portion 141 and the dimension D2 of the second portion 142 in the Z-axis direction, may be 15% to 30% of the dimension T from the first surface 120 to the second surface 130. This configuration ensures a sufficient area for the main side surface 143. This allows the internal wiring 320 to be more easily exposed on the main side surface 143, which is the connection portion between adjacent wiring substrates in the motherboard state, rather than on the inclined surfaces 140B and 140C, thereby facilitating electrical connection between the wiring substrates in the motherboard state. Facilitating electrical connection between the wiring substrates facilitates plating on the wiring conductors 300 of the wiring substrate 500. Here, the value of the dimension T may be, for example, 0.3 mm to 2.0 mm.

[0040] 3 and 5 may have the same or similar surface shape as the first portion 141. The fourth portion 144 may have the same or similar surface shape as the second portion 142.

[0041] The dimension D5 of the fifth portion 145 in the Z-axis direction may be the same as or different from the dimension D1 of the first portion 141. The dimension D4 of the fourth portion 144 in the Z-axis direction may be the same as or different from the dimension D2 of the second portion 142. The dimension D45 obtained by adding the dimensions D4 and D5 may be the same as or different from the dimension D12.

[0042] The dimension D3 of the main side surface 143 in the Z-axis direction may be 40% to 70% of the dimension T. With this configuration, the area of ​​the main side surface 143 can be ensured.

[0043] 13 and 14 are diagrams illustrating a wiring substrate 500 according to another embodiment of the present disclosure. In another embodiment, the wiring substrate 500 may have an opening 121 in the first surface 120. The opening 121 may penetrate the wiring substrate 500. The opening 121 may also be positioned offset toward one of the side surfaces 140 in the X-axis direction or the Y-axis direction. More specifically, as shown in FIGS. 13 and 14 , a distance L1 from the first portion 141 to the opening 121 in the X-direction may be greater than a distance L2 from the first portion 141 to the opening 121 in the Y-direction.

[0044] The main side surface 143 may have one or more protrusions that protrude toward the outside of the wiring substrate 500 (the X direction or Y direction in the drawings). By having such protrusions, the heat dissipation properties of the wiring substrate 500 can be improved. The protrusions may be integral with the insulating substrate 100. The protrusions may also be so-called burrs that are generated when the mother substrate is cut along the division grooves G. A protrusion may be defined as a portion whose dimensions in the X direction, Y direction, and Z direction are larger than those of the convex portion 142P.

[0045] 13 and 14 , the wiring substrate 500 may have a first protrusion 1431 protruding in the X direction from a main side surface 143 along the Y direction and a second protrusion 1432 protruding in the Y direction from the main side surface 143 along the X direction. The first protrusion 1431 and the second protrusion 1432 are examples of protrusions of the present disclosure. A plurality of the first protrusions 1431 and the second protrusions 1432 may be located on each main side surface 143. Furthermore, a distance T1 (hereinafter also referred to as a first protrusion amount T1) from the main side surface 143 along the Y direction to a point where the first protrusion 1431 is farthest from the main side surface 143 in the X direction may be smaller than a distance T2 (hereinafter also referred to as a second protrusion amount T2) from the main side surface 143 along the X direction to a point where the second protrusion 1432 is farthest from the main side surface 143 in the Y direction.

[0046] When the wiring substrate 500 has an opening 121, and the distance L1 from the first portion 141 to the opening 121 in the X direction is greater than the distance L2 from the first portion 141 to the opening 121 in the Y direction, the thickness of the side of the wiring substrate 500 along the X direction is smaller than the thickness of the side of the wiring substrate 500 along the Y direction. In this case, the second protrusion amount T2 of the second protrusion 1432 protruding in the Y direction from the main side surface 143 along the X direction may be greater than the first protrusion amount T1 of the first protrusion 1431 protruding in the X direction from the main side surface 143 along the Y direction, thereby improving the heat dissipation performance of the wiring substrate 500 along the X direction and reducing bias in the heat dissipation performance of the wiring substrate 500 in the X and Y directions. In other words, when the distance L1 is greater than the distance L2, the first protrusion amount T1 may be less than the second protrusion amount T2.

[0047] Furthermore, when the wiring substrate 500 has a shape having short sides and long sides, the heat capacity tends to be small on the short sides because the volume of the components constituting the wiring substrate 500 is smaller than on the long sides. Therefore, by making the second protrusion amount T2 of the second protrusion portion 1432 protruding from the main side surface 143 located on the short side larger than the first protrusion amount T1 of the first protrusion portion 1431 protruding in the X direction from the main side surface 143 located on the long side, bias in heat dissipation performance when the wiring substrate 500 has a shape having short sides and long sides may be reduced. When the length of one side is t1 and the length of another side is t2, if t1 > t2, the first protrusion amount T1 may be smaller than the second protrusion amount T2.

[0048] [Summary] (1) The wiring board in aspect 1 of the present disclosure comprises an insulating substrate having a first surface and a plurality of side surfaces connected to the first surface, at least one of the side surfaces having a main side surface, at least a portion of which is located in a central portion in the thickness direction of the side surface, and a sloping surface connecting the first surface and the main side surface, the sloping surface having a first portion connected to the first surface and a second portion located between the first portion and the main side surface, the first portion and the second portion having different surface shapes, and the second portion having a plurality of protrusions.

[0049] (2) In a wiring board according to a second aspect of the present disclosure, in the above-described first aspect, the insulating substrate further includes a corner portion located between the side surfaces, and the dimension of the main side surface in the thickness direction of the insulating substrate decreases toward the corner portion.

[0050] (3) In a third aspect of the present disclosure, the wiring board is the same as in the first or second aspect, wherein the plurality of protrusions extend in a direction along the first surface.

[0051] (4) In a fourth aspect of the present disclosure, the wiring board is the same as any one of the first to third aspects, wherein the inclination of the first portion relative to the main side surface is greater than the inclination of the second portion relative to the main side surface.

[0052] (5) In a fifth aspect of the present disclosure, the wiring board is the same as in any one of the first to fourth aspects, wherein the first portion has a convex curved surface portion.

[0053] (6) In a sixth aspect of the present disclosure, the wiring board is the same as in the fourth aspect, wherein the dimension of the first portion is larger than the dimension of the second portion in a direction perpendicular to the first surface.

[0054] (7) A wiring board according to a seventh aspect of the present disclosure is the wiring board according to any one of the first to sixth aspects, wherein the first portion includes a plurality of grooves extending in a direction from the first surface toward the second portion.

[0055] (8) In aspect 8 of the present disclosure, the wiring board is any one of aspects 1 to 7 above, wherein the insulating substrate has a second surface located opposite the first surface, and in a direction perpendicular to the first surface, the combined dimension of the first portion and the second portion is 15% or more and 30% or less of the dimension from the first surface to the second surface.

[0056] (9) A ninth aspect of the present disclosure provides a wiring board according to any one of the first to eighth aspects, wherein the spacing between the plurality of protrusions is 1 μm or more and 20 μm or less.

[0057] (10) In a tenth aspect of the present disclosure, the wiring board is the same as the ninth aspect, wherein the intervals between the protrusions increase with increasing distance from the first surface.

[0058] (11) In an eleventh aspect of the present disclosure, the wiring board of any one of the first to tenth aspects further includes a wiring conductor located within the insulating substrate, and a portion of the wiring conductor is exposed on the main side surface.

[0059] (12) In a twelfth aspect of the present disclosure, the wiring board is the same as in any one of the first to eleventh aspects, wherein the first portion does not have a protrusion extending in a direction along the first surface.

[0060] (13) In a thirteenth aspect of the present disclosure, in the wiring board of any one of the first to twelfth aspects, the surface roughness of the main side surface is greater than the surface roughness of the first portion.

[0061] (14) A wiring board according to a fourteenth aspect of the present disclosure is the wiring board according to any one of the first to thirteenth aspects, wherein the main side surface has one or more protrusions that protrude outward from the wiring board.

[0062] (15) An electronic module according to aspect 15 of the present disclosure includes the wiring board according to any one of aspects 1 to 14 above, and an electronic component located on the wiring board.

[0063] The invention according to the present disclosure has been described above based on the drawings and examples. However, the invention according to the present disclosure is not limited to the above-described embodiments. In other words, the invention according to the present disclosure can be modified in various ways within the scope of the present disclosure, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the invention according to the present disclosure. In other words, it should be noted that a person skilled in the art can easily make various modifications or corrections based on the present disclosure. It should also be noted that these modifications or corrections are included in the scope of the present disclosure.

[0064] REFERENCE SIGNS LIST 100 insulating substrate 120 first surface 121 opening 130 second surface 140 side surface 140B, 140C inclined surface 141 first portion 142 second portion 142P convex portion 143 main side surface 1431 first protrusion 1432 second protrusion 150 corner portion 300 wiring conductor 310 connection electrode 320 internal wiring 500 wiring substrate 600 electronic component 700 electronic module

Claims

1. A wiring board comprising an insulating substrate having a first surface and a plurality of side surfaces connected to the first surface, at least one of the side surfaces having a main side surface, at least a portion of which is located in the center of the thickness direction of the side surface and has a surface parallel to the thickness direction, and an inclined surface connecting the first surface and the main side surface, the inclined surface having a first portion connected to the first surface and a second portion located between the first portion and the main side surface, the first portion and the second portion having different surface shapes, and the second portion having a plurality of protrusions.

2. The wiring board according to claim 1, wherein the insulating substrate further comprises a corner portion located between the side surfaces, and the dimension of the main side surface in the thickness direction of the insulating substrate decreases toward the corner portion.

3. The wiring board according to claim 1 or 2, wherein the plurality of protrusions extend in a direction along the first surface.

4. The wiring board according to claim 1, wherein the inclination of the first portion relative to the main side surface is greater than the inclination of the second portion relative to the main side surface.

5. The wiring board according to any one of claims 1 to 4, wherein the first portion has a convex curved surface.

6. The wiring board according to claim 4, wherein the dimension of said first portion is larger than the dimension of said second portion in a direction perpendicular to said first surface.

7. The wiring board according to any one of claims 1 to 6, wherein the first portion has a plurality of grooves extending in a direction from the first surface toward the second portion.

8. A wiring board according to any one of claims 1 to 7, wherein the insulating substrate has a second surface located opposite the first surface, and the combined dimension of the first portion and the second portion in a direction perpendicular to the first surface is 15% to 30% of the dimension from the first surface to the second surface.

9. The wiring board according to any one of claims 1 to 8, wherein the intervals between the plurality of protrusions are 1 μm or more and 20 μm or less.

10. The wiring board according to claim 9, wherein the distance between the adjacent protrusions increases with increasing distance from the first surface.

11. The wiring board according to any one of claims 1 to 10, further comprising a wiring conductor located within said insulating substrate, a portion of said wiring conductor being exposed at said main side surface.

12. The wiring board according to any one of claims 1 to 11, wherein the first portion does not have a protrusion extending in a direction along the first surface.

13. The wiring board according to any one of claims 1 to 12, wherein the surface roughness of the main side surface is greater than the surface roughness of the first portion.

14. The wiring board according to any one of claims 1 to 13, wherein the main side surface has one or more protrusions that protrude outward from the wiring board.

15. An electronic module comprising: a wiring board according to any one of claims 1 to 14; and an electronic component located on the wiring board.

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