Wiring board and electronic module

Abstract

The present invention improves the quality of a wiring board. The wiring board has: a first outer-edge surface that is a surface connecting side surfaces and extends in a thickness direction from a first surface; and a second outer-edge surface that is a surface connecting the side surfaces, extends in the thickness direction from a second surface, and is positioned outside the first outer-edge surface in a plan view. The side surfaces of the wiring board each have a main side surface positioned at a central portion and a first inclined surface connecting the main side surface and an upper surface, and the first inclined surface has a plurality of protrusions. An area in which the plurality of protrusions are present in the thickness direction overlaps an area in which the first outer-edge surface is present.

Description

Wiring boards and electronic modules

[0001] This disclosure relates to a wiring board and an electronic module.

[0002] A wiring board for mounting electronic components, consisting of multiple ceramic layers, is 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 and a wiring conductor, wherein the insulating substrate has a first surface, a second surface opposite to the first surface, a plurality of side surfaces connecting the first surface and the second surface, a surface connecting the two side surfaces, a first outer edge surface extending in the thickness direction from the first surface, and a second outer edge surface connecting the two side surfaces, extending in the thickness direction from the second surface and located outside the first outer edge surface in a plan view, wherein the side surfaces have a main side surface located including the central portion of the side surface in the thickness direction, and a first inclined surface connecting the first surface and the main side surface, the first inclined surface having a plurality of protrusions, and the area in which the plurality of protrusions exist in the thickness direction overlaps with at least the area in which the first outer edge surface exists in the thickness direction.

[0005] An electronic module according to one aspect of this disclosure comprises the above-mentioned wiring board and electronic components.

[0006] This is a perspective view of an electronic module according to an embodiment of the present disclosure. This is an enlarged view of region P in Figure 1. This is a micrograph of region Q shown in Figure 2. This is a cross-sectional view taken along the line IV-IV in Figure 2. This is a micrograph of a part of the side surface of a wiring board according to an embodiment of the present disclosure. This is a micrograph of the side surface of a wiring board according to an embodiment of the present disclosure, taken from an oblique upward direction relative to the wiring board. This is a micrograph showing the surface shape of the first portion of a wiring board according to an embodiment of the present disclosure. This is a micrograph showing the surface shape of the second portion of a wiring board according to an embodiment of the present disclosure. This is a micrograph taken from an oblique upward direction relative to the master substrate in the state of the master substrate before the wiring board is separated into individual pieces.

[0007] In the case of the wiring boards described above, there is a need for improved quality of the wiring boards.

[0008] According to one aspect of this disclosure, it is possible to improve the heat dissipation of a wiring board while reducing the possibility of damage to the wiring board.

[0009] [Embodiments] Wiring boards and electronic modules according to embodiments of the present disclosure will be described in detail with reference to the attached drawings.

[0010] The distinction between "up" and "down" in the following description is for convenience only and does not limit the actual orientation of the printed circuit board and electronic module when they are used. In this specification, the side of the printed circuit board on which electronic components are mounted is defined as the first surface (top surface). Also, in the drawings, the positive Z-axis direction is defined as the up direction. The X-axis direction is the minor axis direction of the printed circuit board, and the Y-axis is the axis perpendicular to the X-axis and Z-axis. Also, the Z-axis direction is defined as the thickness direction of the printed circuit board.

[0011] Figure 1 is a perspective view of an exemplary electronic module 700 of the present disclosure. Figure 2 is an enlarged view of region P in Figure 1. Figure 3 is a micrograph of region Q shown in Figure 2. As shown in Figure 1, the electronic module 700 comprises a wiring board 500 and electronic components 600. The wiring board 500 has an insulating substrate 100 and wiring conductors 300.

[0012] In Figure 1, the outline of the electronic component 600 is shown by a dashed line. The electronic component 600 may be mounted on the first surface 120 by bonding with a bonding material such as brazing material, glass, or adhesive, or it may be mounted indirectly 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, for example, a CCD (Charge-Coupled Device) element or a CMOS (Complementary Metal-Oxide Semiconductor) element. Alternatively, the electronic component 600 may be a display element such as a liquid crystal display. Figure 1 shows an example in which one electronic component 600 is mounted on the wiring board 500, but the electronic module 700 may have multiple electronic components 600 of multiple types mounted on it.

[0013] The insulating substrate 100 may be, for example, a flat plate-shaped insulator having a substantially rectangular shape in plan view. The insulating substrate 100 shown in Figure 1 has a first surface 120, a second surface 130 located opposite the first surface 120, and four side surfaces 140.

[0014] The first surface 120 may include a mounting area for mounting electronic components 600. The mounting area on the first surface 120 may be an area that overlaps with the electronic components 600 when the wiring board 500 is viewed from above. The first surface 120 may also have a plurality of connecting electrodes 310 that are electrically connected to the electrodes of the electronic components 600. The connecting electrodes 310 may be electrically connected to the electrodes of the electronic components 600 via a conductive bonding material such as bonding wire or solder. The insulating substrate 100 may have recesses on the first surface 120 for housing the electronic components 600. The insulating substrate 100 may also have through holes in a part of the mounting area that penetrate from the first surface 120 to the second surface 130.

[0015] As shown in Figure 2, the insulating substrate 100 further has a corner surface 150 connecting the first side surface 1401 and the second side surface 1402, which is a virtual corner of the insulating substrate 100. In other words, the insulating substrate 100 may have chamfered edges on its rectangular corners, and the corner surface 150 may be the surface of such chamfered edges. By chamfering the corners of the insulating substrate 100, the possibility of chipping at the corners of the insulating substrate 100 can be reduced.

[0016] The corner surface 150 is a surface connecting the first side surface 1401 and the second side surface 1402, and has a first outer edge surface 151 extending in the Z direction from the first surface 120. The corner surface 150 further has a second outer edge surface 152, which is a surface connecting the first side surface 1401 and the second side surface 1402, and extends in the Z direction from the second surface 130, and is located outside the first outer edge surface 151 in a plan view. In other words, the second outer edge surface 152 is located further from the center of the wiring board 500 than the first outer edge surface 151. In this specification, "inside (direction)" of the wiring board 500 or insulating board 100 means the direction toward the center of the wiring board 500 or insulating board 100. "Outside (direction)" of the wiring board 500 or insulating board 100 means the direction away from the center of the wiring board 500 or insulating board 100.

[0017] The first outer edge surface 151 and the second outer edge surface 152 may be concave curved surfaces that are recessed in the direction toward the inside of the insulating substrate 100, as shown in Figures 2 and 3. In other words, the first outer edge surface 151 may have a concave curve formed by the edge of the first outer edge surface 151 when viewed from above, recessed in the direction toward the inside of the insulating substrate 100, and may be a surface that extends substantially perpendicular to the first surface 120. The second outer edge surface 152 may have a concave curve formed by the edge of the second outer edge surface 152 when viewed from above, recessed in the direction toward the inside of the insulating substrate 100, and may be a surface that extends substantially perpendicular to the first surface 120. The curvature of the concave curve formed by the edges of the first outer edge surface 151 and the second outer edge surface 152 when viewed from above may be the same or may be different.

[0018] Because the first outer edge surface 151 and the second outer edge surface 152 are concave curved surfaces, the surface area of ​​the insulating substrate 100 increases compared to when they are flat, thus improving heat dissipation.

[0019] The corner surface 150 further has a third outer surface 153 that connects the first outer surface 151 and the second outer surface 152. The third outer surface 153 may be a surface parallel to the plane including the first surface 120. This configuration allows the first outer surface 151 and the second outer surface 152 extending in the thickness direction to be made larger, thereby further reducing the possibility of collision between the wiring board 500 and other components at the corner and the possibility of damage to the corner of the wiring board 500.

[0020] Figure 4 is a cross-sectional view taken along the line IV-IV in Figure 2. More specifically, Figure 4 shows a cross-section of the wiring board 500 obtained by cutting it with a plane perpendicular to the first surface 120 and cutting through the second outer edge surface 152. As shown in Figure 4, in this cross-section, the wiring board 500 has a distance L from the third outer edge surface 153 to the second surface 130. ４ However, the thickness of the insulating substrate 100 may decrease at its edges as it moves outward from the insulating substrate 100. In the wiring board 500, the thickness of the insulating substrate 100 located in the region outside the first outer edge surface 151 when the wiring board 500 is viewed from above may decrease as it moves outward from the wiring board 500. In other words, the second surface 130 may curve upward as it moves towards a hypothetical corner of the wiring board 500. This configuration further reduces the possibility of collision with other components, even at the corners of the lower surface of the wiring board 500.

[0021] As shown in Figures 3 and 4, the insulating substrate 100 may have a notch 154 at the boundary between the first outer edge surface 151 and the third outer edge surface 153. This configuration further increases the surface area of ​​the insulating substrate 100, thereby improving heat dissipation. When the insulating substrate 100 has a notch 154, internal wiring 320 located on the same plane as the notch 154 may be positioned with a gap between them and the notch 154. Because the internal wiring 320 is spaced apart from the notch 154, that is, the internal wiring 320 is not exposed to the notch 154, the possibility of the internal wiring 320 coming into contact with moisture is reduced even if the wiring substrate 500 is exposed to moisture. This reduces the possibility of the internal wiring 320 corroding. The notch 154 does not need to be located across the entire boundary between the first outer edge surface 151 and the third outer edge surface 153; for example, it may be spaced apart from the main surface 143.

[0022] The connecting electrode 310 may be a part of the wiring conductor 300 of the wiring board 500. As shown in Figure 2, the wiring conductor 300 of the wiring board 500 may have internal wiring 320 located inside the insulating substrate 100 and extending in a direction parallel to the first surface 120, in addition to the connecting electrode 310. The wiring conductor 300 may also include via conductors extending in the thickness direction of the insulating substrate 100. The wiring conductor 300 may further include external terminal electrodes located on the second surface 130 and electrically connected to electrodes of external equipment. The connecting electrode 310 may be electrically connected to the external terminal electrodes via via conductors and / or internal wiring 320.

[0023] The insulating substrate 100 may be a ceramic 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.

[0024] The wiring board 500 may be a substrate formed by cutting a master substrate along a dividing groove. Specifically, the wiring board 500 may be manufactured, for example, by creating a master substrate and dividing the master substrate into individual pieces. The master substrate can also be called a multi-piece substrate. The master substrate has a plurality of wiring board regions arranged vertically and horizontally on the substrate surface. The wiring board regions are regions that are divided into individual pieces to become the wiring board 500. The master substrate has a dividing groove at the boundary between two adjacent wiring board regions, and by breaking the master substrate along the dividing groove, individual pieces of the wiring board 500 can be obtained.

[0025] The two wiring board regions do not necessarily have to be adjacent. For example, a portion not used as wiring board 500 (hereinafter referred to as a dummy region) may be formed between the two wiring board regions, and the wiring board regions may be arranged with the dummy region in between. In other words, a dummy region may be located between each wiring board region on the master board.

[0026] The divided grooves can be formed, for example, by partially removing the base substrate before or after firing using a laser. Examples of lasers used for forming the divided grooves include carbon dioxide lasers, fiber lasers, YAG (Yttrium-Aluminum-Garnet) lasers, femtosecond lasers, or picosecond lasers. Femtosecond or picosecond lasers remove the target material by severing interatomic bonds with photons. Therefore, when a femtosecond or picosecond laser is used to form the divided grooves, the thermal impact on the wiring board 500 can be reduced compared to when a fiber laser or the like is used to form the divided grooves on the base substrate.

[0027] As shown in Figures 2 and 3, the side surface 140 of the wiring board 500 has a main side surface 143 located in the central part of the thickness direction (Z direction) of the side surface 140 and having a surface parallel to the thickness direction, and a first inclined surface 140B connecting the first surface 120 and the main side surface 143. The first inclined surface 140B has a first portion 141 connected to the first surface 120 and a second portion 142 located between the first portion 141 and the main side surface 143. In this specification, "parallel" does not need to be strictly parallel, but may be approximately parallel. For example, the main side surface 143 may be slightly inclined with respect to the Z axis (up to about ±5°). Also, if the main side surface 143 is not strictly flat, it may be mainly parallel to the Z axis.

[0028] The main surface 143 may have one or more protrusions that project outward from the wiring board 500. Having such protrusions can improve the heat dissipation of the wiring board 500. The protrusions may be integrated with the insulating substrate 100. The protrusions may also be so-called burrs that are formed when the base substrate is cut along the dividing groove G. A protrusion may be defined as a portion whose protrusion height from the main surface 143 is higher than the protrusion height from the second portion 142 of the convex portion 142P, which will be described later.

[0029] The side surface 140 of the wiring board 500 may also have a second inclined surface 140C on the second surface 130 side, connecting the second surface 130 and the main side surface 143. The second inclined surface 140C may have a fifth portion 145 connected to the second surface 130 and a fourth portion 144 located between the fifth portion 145 and the main side surface 143. In other words, the wiring board 500 may have a main side surface 143 located in the center of the side surface 140 in the thickness direction, and a first inclined surface 140B and a second inclined surface 140C located on the first surface 120 side and the second surface 130 side of the main side surface 143, respectively. The fifth portion 145 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.

[0030] If the wiring board 500 is a board manufactured by dividing a master board, the first inclined surface 140B and the second inclined surface 140C may be surfaces corresponding to the surface (also called the inner surface of the groove) of the dividing groove G in the master board (see Figure 9). Also, the main side surface 143 may be a portion corresponding to the fracture surface formed when the master board is broken when it is divided.

[0031] The structure of the side surface 140 of the wiring board 500 will be described in more detail below.

[0032] Figure 5 is a micrograph of a portion of the side surface 140. Figure 6 is a micrograph of the side surface 140 taken from an oblique upward direction relative to the wiring board 500. Figure 7 is a micrograph showing the surface shape of the first portion 141. Figure 8 is a micrograph showing the surface shape of the second portion 142. Figures 7 and 8 were taken at the same scale. Figure 9 is a micrograph of the dividing groove G taken from an oblique upward direction relative to the base substrate in the state of the base substrate before the wiring board 500 is separated into individual pieces. However, to facilitate observation, Figure 9 was taken using a wiring board with the corner surface 150 omitted.

[0033] As shown in Figures 3 and 5 to 8, the first inclined surface 140B has different surface shapes from the first portion 141 and the second portion 142. The difference in surface shapes between the first portion 141 and the second portion 142 will be explained in detail below.

[0034] As shown in Figures 3, 5, and 6, the second portion 142 has a plurality of protrusions 142P. The protrusions 142P may extend in a direction along the first surface 120. The protrusions 142P extending along the first surface 120 do not have to be linear and may have a wave shape. In other words, the protrusions 142P may be wavy and their distance from the first surface 120 may vary. The plurality of protrusions 142P extending along the first surface 120 may each be located at different heights on the wiring board 500. Due to the plurality of protrusions 142P located at different heights on the wiring board 500 and extending along the first surface 120, the surface of the second portion 142 may be stepped.

[0035] The spacing between the multiple protrusions 142P may be between 1 μm and 20 μm. In this specification, the spacing between the protrusions 142P may be the spacing between the tips of the protrusions 142P when viewed from a direction perpendicular to the main surface 143 (Y direction). As shown in Figure 5, this spacing may increase as it moves away from the first surface 120.

[0036] The presence of multiple protrusions 142P in the second portion 142 increases the surface area of ​​the second portion 142. This may improve the heat dissipation of the wiring board 500. Furthermore, because the protrusions 142P extend along the first surface 120, the possibility of the bonding material used to join the electronic components 600 and the wiring board 500 reaching the main side surface 143 when it flows from the first surface 120 towards the side surface 140 is reduced. This reduces the possibility of the external dimensions of the wiring board 500 being altered by the bonding material. This effect of restricting the movement of the bonding material is more easily obtained when the distance between the protrusions 142P increases as it moves away from the first surface 120. Moreover, the effects of improved heat dissipation and restriction of bonding material movement are more easily obtained when the distance between the protrusions 142P is between 1 μm and 20 μm.

[0037] Furthermore, the second portion 142 may have a melt-re-solidified layer. The melt-re-solidified layer is a layer formed when ceramic that has been melted by laser irradiation is re-solidified by cooling. As shown in Figures 7 and 8, the presence of the melt-re-solidified layer in the second portion 142 makes the surface of the second portion 142 smoother compared to the first portion 141. As a result, when the insulating substrate 100 is made of ceramic material, the melt-re-solidified second portion 142 reduces the possibility of the ceramic material on the surface of the insulating substrate 100 peeling off. The aforementioned protrusion 142P may be located on the surface of the melt-re-solidified layer.

[0038] Unlike the above-described second portion 142, the first portion 141 does not have a convex portion 142P that extends at least in the direction along the first surface 120. That is, in the first inclined surface 140B, a portion without the convex portion 142P may be defined as the first portion 141, and a portion with the convex portion 142P may be defined as the second portion 142. As shown in FIG. 9, the first portion 141 may include a plurality of grooves 141C that extend in the 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 may be finer than the unevenness of the surface of the second portion 142 formed by the convex portion 142P in the second portion 142. Both the first portion 141 and the second portion 142 may have a melt re-solidified layer.

[0039] By providing the first portion 141 with a plurality of grooves, the heat dissipation performance of the wiring board 500 may be further improved.

[0040] Thus, the first portion 141 and the second portion 142 have different surface shapes. Such different surface shapes can be brought about by changing the laser irradiation conditions between the portion corresponding to the first portion 141 and the portion corresponding to the second portion 142 when creating the dividing groove G by laser in the state of the mother substrate. The laser irradiation conditions may be, for example, one or more conditions selected from the following conditions: the type of laser, intensity, irradiation angle, continuous irradiation time, spot diameter of the laser to be irradiated, overlapping rate of the laser spots in the direction in which the dividing groove extends, number of laser irradiations in the direction intersecting the direction in which the dividing groove extends, and overlapping rate of the laser spots in the direction intersecting the direction in which the dividing groove extends. The laser irradiation conditions can be appropriately changed according to the material of the insulating substrate 100.

[0041] The wiring board 500 includes an insulating substrate 100 and a wiring conductor 300. The insulating substrate 100 has a first surface 120, a second surface 130, a first outer edge surface 151, and a second outer edge surface 152. The side surface 140 has a main side surface 143 and a first inclined surface 140B connecting the first surface 120 and the main side surface 143. The first inclined surface 140B has a plurality of convex portions 142P, and the range where the plurality of convex portions 142P exist in the thickness direction of the wiring board 500 overlaps at least with the range where the first outer edge surface 151 exists in the thickness direction.

[0042] The insulating substrate 100 has a first outer edge surface 151 located inside the wiring board 500 than the second outer edge surface 152. Thereby, at the corner portion on the first surface 120 side which is likely to be damaged due to collision with other components, the possibility of collision between the wiring board 500 and other components and the possibility of the corner portion of the wiring board 500 being damaged can be further reduced. On the other hand, by having the first outer edge surface 151, in the thickness direction, the volume of the insulating substrate 100 in the region where the first outer edge surface 151 is located becomes smaller compared to the case where it does not have the first outer edge surface 151, so there is a possibility that the heat dissipation performance of the region decreases. Since the range where the plurality of convex portions 142P of the first inclined surface 140B exist in the thickness direction overlaps with the range where the first outer edge surface 151 exists, the heat dissipation property in the portion where the volume of the insulating substrate 100 is small in the thickness direction can be improved. Thereby, the quality of the wiring board 500 can be improved.

[0043] In addition, since the second outer edge surface 152 is outside the first outer edge surface 151, it becomes easier to distinguish the top and bottom of the wiring board 500, and the possibility of misidentifying the front and back of the wiring board 500 during the mounting of the electronic component 600 can be reduced.

[0044] Also, the range where the third outer edge surface 153 exists in the thickness direction of the wiring board 500 may overlap with the range where the main side surface 143 exists in the thickness direction. With this configuration, since the lower end of the first outer edge surface 151 is located in the region where the main side surface 143 is located in the thickness direction, the possibility of collision with other components at the virtual corner portion of the wiring board 500 can be significantly reduced.

[0045] Furthermore, the wiring board 500 has a main surface 143 and a first inclined surface 140B. The first inclined surface 140B has a first portion 141 connected to the first surface 120 and a second portion 142 located between the first portion 141 and the main surface 143, and the first portion 141 and the second portion 142 may have different surface shapes. The second portion 142 may also have a plurality of protrusions 142P. With this configuration, by having the protrusions 142P in the second portion closer to the center of the board in the thickness direction, it is possible to improve the heat dissipation of the wiring board while reducing the possibility of the protrusions 142P being damaged by collision with other components.

[0046] If the insulating substrate 100 is made of ceramics and the first inclined surface 140B is a surface formed by laser irradiation, the protrusions 142P can be easily formed by irradiating the insulating substrate 100 with a laser after firing. Furthermore, by forming the protrusions 142P on the insulating substrate 100 after firing, the possibility of the protrusions 142P being crushed during firing can be reduced compared to forming the protrusions 142P on the insulating substrate 100 before firing, thus reducing the possibility of reduced heat dissipation effect from the protrusions 142P.

[0047] Furthermore, the first portion 141 may have a surface shape different from that of the first outer edge surface 151 and the second outer edge surface 152. Specifically, the surface roughness of the first portion 141 may be less than that of the first outer edge surface 151 and the second outer edge surface 152. When the insulating substrate 100 is made of ceramics, the first outer edge surface 151 and the second outer edge surface 152 may be surfaces formed by punching a ceramic green sheet. On the other hand, the first inclined surface 140B may be a surface formed by laser irradiation. By being irradiated with a laser, the surface roughness of the first portion 141 can be reduced to that of the first outer edge surface 151 and the second outer edge surface 152. The surface roughness in this disclosure may be the arithmetic mean roughness Ra, which can be measured, for example, by an AFM (Atomic Force Microscope).

[0048] The first portion 141 is a part that is likely to come into contact with other wiring boards or dummy areas when the wiring board 500 is separated into individual pieces from the master substrate. By making the surface roughness of the first portion 141 small, even if the first portion 141 comes into contact with other wiring boards 500 or dummy areas, the possibility of chipping or snagging on each other, which would hinder the separation of the wiring board into individual pieces, can be reduced.

[0049] Next, the main side surface 143 will be described in detail. The surface roughness of the main side surface 143 may be greater than that of the first portion 141. In other words, the surface roughness of the first portion 141 may be less than that of the main side surface 143. By reducing the surface roughness of the first portion 141, the corners connecting to the first surface 120 of the wiring board 500 become smoother, thereby reducing the possibility of chipping occurring in the wiring board 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.

[0050] Furthermore, as shown in Figure 2, the ends of the internal wiring 320 may be exposed on the main side surface 143. By exposing a portion of the internal wiring 320 to the surface of the wiring board 500, the heat dissipation of the wiring board 500 may be further improved. Also, by exposing the ends of the internal wiring 320 to the main side surface 143, the conductivity of the internal wiring 320 can be checked through these ends.

[0051] The main surface 143 may have an adjacent region 149 adjacent to the second outer edge surface 152, as shown in Figures 2 and 3. More specifically, the adjacent region 149 may be the region adjacent to the second outer edge surface 152 and the third outer edge surface.

[0052] The adjacent region 149 may be located further inside the wiring board 500 than other areas of the main surface 143. In other words, the adjacent region 149 may be a recessed area compared to other areas of the main surface 143. By having the adjacent region 149 adjacent to the second outer edge surface 152 located further inside the board than other areas of the main surface 143, the possibility of the end near the second outer edge surface 152 coming into contact with other components is reduced, thereby reducing the possibility of the wiring board 500 being chipped.

[0053] The surface state of the adjacent region 149 may differ from that of the main surface 143. Specifically, if the insulating substrate 100 is made of ceramics, the adjacent region 149 may have a melted and resolidified layer formed by irradiation with a laser. In other words, the surface state of the adjacent region 149 may be the same as or similar to that of the second portion 142, as shown in Figure 8. On the other hand, the main surface 143 other than the adjacent region 149 may be the part corresponding to the fracture surface formed when the base substrate is fractured when the base substrate is divided, as already explained. Furthermore, the adjacent region 149 and the areas other than the adjacent region 149 on the main surface 143 may have different colors when viewed visually.

[0054] The presence of a melted and re-solidified layer in the adjacent region 149 makes it less likely for the edges near the second outer edge to chip. Furthermore, since the edges of the main surface 143 have adjacent regions 149 separated by a laser from the adjacent substrate or dummy portion, it becomes easier to separate each wiring board 500 from the master substrate into individual pieces.

[0055] Furthermore, the adjacent region 149 may have a different surface roughness from the first outer edge surface 151 and the second outer edge surface 152. Specifically, the surface roughness of the adjacent region 149 may be less than the surface roughness of the first outer edge surface 151 and the second outer edge surface 152.

[0056] The adjacent region 149 is a location that is likely to come into contact with an adjacent wiring board 500 or dummy portion when the wiring board 500 is separated into individual pieces from the master substrate. This adjacent region 149 has a smoother surface than the first outer edge surface 151 and the second outer edge surface 152. As a result, even if the adjacent region 149 comes into contact with an adjacent wiring board 500 or dummy portion, the possibility of chipping or snagging on each other, which would hinder the separation of the wiring board 500 into individual pieces, can be reduced.

[0057] The width direction of the main surface 143 is defined as the direction perpendicular to the thickness direction (Z-axis direction in the drawing) (Y-axis direction in the drawing), and the length of the adjacent region 149 in the width direction is defined as length L. １ In the wiring board 500, the length L １As shown in FIG. 2, it may become smaller as it progresses in the direction from the first surface 120 toward the second surface 130. More specifically, the adjacent region 149 may have a region where the length L １ is substantially constant and a region that gradually becomes smaller as it progresses in the direction from the first surface 120 toward the second surface 130. The length L １ The region that gradually becomes smaller may be located below the adjacent region 149. Alternatively, the adjacent region 149 may have a shape in which the length L １ gradually becomes smaller from the upper end to the lower end of the adjacent region 149.

[0058] When the adjacent region 149 has a region where the length L １ gradually becomes smaller, it is more likely to be a starting point of breakage when the wiring substrate 500 is separated into individual pieces from the mother substrate as compared with the case where the length L １ is constant. Therefore, breakage along the outer shape of the wiring substrate 500 from the adjacent wiring substrate 500 or the dummy portion becomes easier.

[0059] Also, the maximum length in the thickness direction of the adjacent region 149 is defined as the length L ２ , and the length in the thickness direction of the region other than the adjacent region 149 of the main side surface 143 is defined as the length L ３ . In the wiring substrate 500, the length L ２ may be 50% or more of the length L ３ . By having the adjacent region 149 separated by laser in 50% or more of the thickness direction of the main side surface 143 corresponding to the fracture surface, the separation of each wiring substrate 500 from the mother substrate becomes easier. Also, breakage along the outer shape of the wiring substrate 500 from the adjacent wiring substrate 500 or the dummy portion in the mother substrate becomes easier.

[0060] The adjacent region 149 may be connected to the second inclined surface 140C. Since the adjacent region 149 separated by laser extends to the second inclined surface 140C, the separation of each wiring substrate 500 from the mother substrate becomes easier. [[ID=(29]]

[0061] [Summary] (1) The wiring board according to Embodiment 1 of the present disclosure comprises an insulating substrate and a wiring conductor, the insulating substrate having a first surface, a second surface opposite to the first surface, a plurality of side surfaces connecting the first surface and the second surface, a surface connecting the two side surfaces, a first outer edge surface extending in the thickness direction from the first surface, and a second outer edge surface connecting the two side surfaces, extending in the thickness direction from the second surface and located outside the first outer edge surface in a plan view, the side surfaces having a main side surface located including the central portion of the side surface in the thickness direction, and a first inclined surface connecting the first surface and the main side surface, the first inclined surface having a plurality of protrusions, and the range in which the plurality of protrusions exist in the thickness direction overlaps with at least the range in which the first outer edge surface exists in the thickness direction.

[0062] (2) In the wiring board according to embodiment 2 of the present disclosure, in embodiment 1, the insulating board has a third outer surface connecting the first outer surface and the second outer surface, and the area in the thickness direction in which the third outer surface exists overlaps with the area in the thickness direction in which the main surface exists.

[0063] (3) In the wiring board according to embodiment 3 of the present disclosure, in embodiment 2, the third outer edge surface is a surface parallel to the plane including the first surface.

[0064] (4) In the wiring board according to embodiment 4 of the present disclosure, in embodiment 3, when the insulating board is cut by a plane perpendicular to the first plane and cutting the second outer edge plane, the distance from the third outer edge plane to the second plane decreases at the edge of the insulating board as it moves outward from the insulating board.

[0065] (5) In any of the embodiments 1 to 4, the wiring board according to embodiment 5 of the present disclosure has a first outer edge surface and a second outer edge surface that are concave curved surfaces.

[0066] (6) In any of embodiments 1 to 5, the wiring board according to embodiment 6 of the present disclosure comprises a ceramic material, the main surface has an adjacent region adjacent to the second outer edge surface, and the surface state of the adjacent region is different from the surface state of other regions of the main surface.

[0067] (7) In the wiring board according to embodiment 7 of the present disclosure, in embodiment 6, when the main side surface is viewed from above, if the direction perpendicular to the thickness direction is defined as the width direction, the length in the width direction of the adjacent region decreases as you move from the first surface toward the second surface.

[0068] (8) In the wiring board according to embodiment 8 of the present disclosure, in embodiment 6 or 7, the maximum length in the thickness direction of the adjacent region is 50% or more of the length in the thickness direction of the other region of the main side surface.

[0069] (9) In any of embodiments 6 to 8, the wiring board according to embodiment 9 of the present disclosure has different surface roughness between the first outer edge surface, the second outer edge surface, and the adjacent region.

[0070] (10) In any of embodiments 1 to 9, the wiring board according to embodiment 10 of the present disclosure has an adjacent region adjacent to the second outer edge surface, and the adjacent region is located inside the board more than other regions of the main side surface.

[0071] (11) In any of the embodiments 1 to 10, the wiring board according to embodiment 11 of the present disclosure has an adjacent region adjacent to the second outer edge surface, the side surface has a second inclined surface connecting the second surface and the main side surface, and the adjacent region is connected to the second inclined surface.

[0072] (12) The wiring board according to embodiment 12 of the present disclosure, in any of embodiments 1 to 11, the first inclined surface has 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 have different surface shapes, and the second portion has the plurality of protrusions.

[0073] (13) In the wiring board according to embodiment 13 of the present disclosure, the first outer edge surface, the second outer edge surface, and the first portion have different surface shapes in embodiment 12.

[0074] (14) In the wiring board according to embodiment 14 of the present disclosure, in any of embodiments 1 to 13, the plurality of protrusions extend in a direction along the first surface.

[0075] (15) An electronic module according to embodiment 15 of the present disclosure comprises a wiring board according to any of embodiments 1 to 14 and an electronic component.

[0076] [Additional Notes] The inventions described in this disclosure have been explained based on the drawings and embodiments. However, the inventions described in this disclosure are not limited to the embodiments described above. That is, the inventions described in this disclosure can be modified in various ways within the scope shown in this disclosure, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the inventions described in this disclosure. In other words, it should be noted that it is easy for those skilled in the art to make various modifications or alterations based on this disclosure. Furthermore, it should be noted that these modifications or alterations are included in the scope of this disclosure.

[0077] 100...Insulating substrate 140...Side surface 140B...First inclined surface 140C...Second inclined surface 141...First part 141C...Groove 142...Second part 142P...Protrusion 143...Main side surface 144...Fourth part 145...Fifth part 149...Adjacent region 1401...First side surface 1402...Second side surface 150...Corner surface 151...First outer edge surface 152...Second outer edge surface 153...Third outer edge surface 154...Notch 300...Wiring conductor 310...Connecting electrode 320...Internal wiring G...Dividing groove 500...Wiring board 600...Electronic component 700...Electronic module

Claims

1. A wiring substrate comprising an insulating substrate and a wiring conductor, wherein the insulating substrate has a first surface, a second surface opposite to the first surface, a plurality of side surfaces connecting the first surface and the second surface, a surface connecting the two side surfaces and having a first outer edge surface extending in the thickness direction from the first surface, and a surface connecting the two side surfaces and having a second outer edge surface extending in the thickness direction from the second surface and located outside the first outer edge surface in a plan view, wherein the side surfaces have a main side surface located including the central portion of the side surface in the thickness direction and a first inclined surface connecting the first surface and the main side surface, the first inclined surface has a plurality of protrusions, and the range in which the plurality of protrusions exist in the thickness direction overlaps with at least the range in which the first outer edge surface exists in the thickness direction.

2. The wiring board according to claim 1, wherein the insulating substrate has a third outer surface connecting the first outer surface and the second outer surface, and the area in the thickness direction in which the third outer surface exists overlaps with the area in the thickness direction in which the main surface exists.

3. The wiring board according to claim 2, wherein the third outer edge surface is a surface parallel to the plane including the first surface.

4. The wiring board according to claim 3, wherein, in a cross-section obtained by cutting the insulating board with a plane perpendicular to the first plane and cutting the second outer edge plane, the distance from the third outer edge plane to the second plane decreases at the edge of the insulating board as it moves outward from the insulating board.

5. The wiring board according to any one of claims 1 to 4, wherein the first outer edge surface and the second outer edge surface are concave curved surfaces.

6. The wiring board according to any one of claims 1 to 5, wherein the insulating substrate comprises a ceramic material, the main surface has an adjacent region adjacent to the second outer edge surface, and the surface state of the adjacent region is different from the surface state of other regions of the main surface.

7. In a plan view of the main surface, if the direction perpendicular to the thickness direction is defined as the width direction, the length of the adjacent region in the width direction decreases as the direction from the first surface toward the second surface, as described in claim 6.

8. The wiring board according to claim 6 or 7, wherein the maximum length in the thickness direction of the adjacent region is 50% or more of the length in the thickness direction of other regions of the main surface.

9. The wiring board according to any one of claims 6 to 8, wherein the first outer edge surface, the second outer edge surface, and the adjacent region have different surface roughnesses.

10. The wiring board according to any one of claims 1 to 9, wherein the main surface has an adjacent region adjacent to the second outer edge surface, and the adjacent region is located inward of the substrate than other regions of the main surface.

11. The wiring board according to any one of claims 1 to 10, wherein the main side surface has an adjacent region adjacent to the second outer edge surface, the side surface has a second inclined surface connecting the second surface and the main side surface, and the adjacent region is connected to the second inclined surface.

12. The wiring board according to any one of claims 1 to 11, wherein the first inclined surface has a first portion connected to the first surface and a second portion located between the first portion and the main side surface, and has different surface shapes from the first portion and the second portion, and the second portion has the plurality of protrusions.

13. The wiring board according to claim 12, wherein the first outer edge surface, the second outer edge surface, and the first portion have different surface shapes.

14. The wiring board according to any one of claims 1 to 13, wherein the plurality of protrusions extend in a direction along the first surface.

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

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