Wiring board and electronic module

Abstract

This wiring board comprises: a substrate having a base body having a first surface and an insulating layer positioned on the first surface; a first electrode and a second electrode positioned on the first surface; and a first via conductor and a second via conductor positioned inside the base body. The first via conductor and the second via conductor are arranged along a first direction, and a first virtual line passing through the center of the first via conductor and extending along the first direction and a second virtual line passing through the center of the second via conductor and extending along the first direction are positioned apart from each other. The first electrode is partially covered by the insulating layer, and the second electrode is spaced apart from the insulating layer in plan view.

Description

Wiring board and electronic module

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

[0002] Conventionally, a substrate for mounting electronic elements has electrode pads for mounting electronic elements and the like on its surface. Patent Document 1 describes a technique for reducing the possibility of damage or the like occurring on the electrode pads by a jig or the like used for mounting in the process of mounting an electronic element or the like on the substrate for mounting electronic elements.

[0003] International Publication No. 2019 / 207884

[0004] The wiring board according to one aspect of the present disclosure includes a substrate having a first surface and an insulating layer located on the first surface, a first electrode located on the first surface, a second electrode located on the first surface and arranged side by side with the first electrode, a first via conductor located in the substrate and connected to the first electrode, and a second via conductor connected to the second electrode. The first via conductor and the second via conductor are arranged side by side along a first direction in which a first side of the first surface extends in a plan view. A first virtual line passing through the center of the first via conductor and along the first direction and a second virtual line passing through the center of the second via conductor and along the first direction are spaced apart from each other. A part of the first electrode is covered by the insulating layer, and the second electrode has a gap from the insulating layer in a plan view.

[0005] This is a perspective view showing the configuration of an electronic module in Embodiment 1 of the present disclosure. This is a side view of an electronic module in Embodiment 1 of the present disclosure. This is a partial plan view of an electronic module in which region A shown in Figure 1 is viewed from above. This is a cross-sectional view taken along the line IV-IV shown in Figure 3. This is a cross-sectional view taken along the line V-V shown in Figure 3. This is a partial plan view of an electronic module in another configuration example of Embodiment 1 of the present disclosure, showing the same region as in Figure 3 in a plan view. This is a cross-sectional view taken along the line VII-VII shown in Figure 6. This is a perspective view showing the configuration of an electronic module in another configuration example of Embodiment 1 of the present disclosure. This is a perspective view showing the configuration of a wiring board in Embodiment 2 of the present disclosure. This is a cross-sectional view taken along the line X-X shown in Figure 9. This is a perspective view showing an enlarged portion of a wiring board to explain the configuration of a wiring board in Embodiment 3 of the present disclosure. This is a partial cross-sectional view showing the configuration of a wiring board in Embodiment 3 of the present disclosure. This is a partial cross-sectional view showing the configuration of a wiring board in another configuration example of Embodiment 3 of the present disclosure.

[0006] [Embodiment 1] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. However, the following description is intended to help you better understand the spirit of the invention and does not limit the present disclosure unless otherwise specified. For the sake of clarity, the figures referenced in the following description show only the main components necessary to explain the embodiment in a simplified manner, and for the sake of simplicity, explanations of known technical matters will be omitted as appropriate.

[0007] Figure 1 is a perspective view showing the configuration of an electronic module in Embodiment 1 of the present disclosure. Figure 2 is a side view of the electronic module in Embodiment 1 of the present disclosure. Figure 3 is a partial plan view of the electronic module, taken from above, of region A shown in Figure 1. Figure 4 is a cross-sectional view taken along the line IV-IV shown in Figure 3. Figure 5 is a cross-sectional view taken along the line V-V shown in Figure 3. In Figure 3, for the sake of clarity, the bonding wire 3 (described later) shown in Figure 1 etc. is omitted from the illustration. Also, in Figure 3, the first via conductor 35 and the second via conductor 45 (described later) in a planar perspective are shown with dotted lines, and for the sake of convenience of explanation, the two imaginary lines described later are shown with dashed lines. In Figure 5, for the sake of convenience of explanation, the first via conductor 35 (described later) shown in Figure 4 in a planar perspective is shown with a dashed line.

[0008] As shown in Figures 1 to 5, an electronic module 1 in one embodiment of the present disclosure comprises a wiring board 10 and an electronic element 2. In the electronic module 1, the electrodes of the electronic element 2 and the electrodes of the wiring board 10 (described later) may be electrically connected to each other by, for example, a bonding wire 3. Not limited to the bonding wire 3, the electrodes of the electronic element 2 and the electrodes of the wiring board 10 (described later) may be electrically connected to each other by a conductive material such as solder, gold, or conductive resin. The electronic element 2 may be any element that can be mounted (mounted) on the wiring board 10, and the specific form of the electronic element 2 is not particularly limited. The bonding wire 3 may be made of a conductive material such as a metal, and known techniques can be applied. A detailed explanation of the bonding wire 3 is omitted. The wiring board 10 in one embodiment of the present disclosure is an electronic element mounting board on which the electronic element 2 is mounted by, for example, a bonding wire 3, and the wiring board 10 in a state before the electronic element 2 is mounted is also included in the scope of the present disclosure.

[0009] For the sake of explanation, the Cartesian coordinate system (in other words, the XYZ coordinate system) shown in Figure 1 will be introduced below. The thickness direction of the wiring board 10 will be the Z-axis direction or the third direction. Viewing an object with a line of sight parallel to the Z-axis will be called a "planar view," and viewing it perspectively will be called a "planar perspective." The side of the wiring board 10 on which the electronic element 2 is located will be the upper side (positive Z-axis direction side). Similarly, the XYZ axis directions will be defined and explained in the following description in this specification, and the XYZ axes will be shown in each figure for reference. Below, we will describe an example in which the first and second directions described later correspond to the X-axis direction and Y-axis direction shown in Figure 1, respectively. However, the X-axis direction and Y-axis direction are directions specified for the sake of explanation, and the first and second directions described later are not limited to the X-axis direction and Y-axis direction shown in Figure 1.

[0010] In one embodiment of the present disclosure, the wiring board 10 comprises a substrate 20, a first electrode 30, a second electrode 40, a first via conductor 35, and a second via conductor 45. The substrate 20 has a base body 25 having a first surface 21, and an insulating layer 60 located on the first surface 21. The first surface 21 is the surface of the base body 25 on which the electronic element 2 is mounted. The first electrode 30 is located on the first surface 21. The second electrode 40 is located on the first surface 21 and is positioned alongside the first electrode 30. The first via conductor 35 is located within the base body 25 and is connected to the first electrode 30. The second via conductor 45 is located within the base body 25 and is connected to the second electrode 40.

[0011] The first via conductor 35 and the second via conductor 45 are aligned in a planar perspective along the first direction (the X-axis direction in the drawing) along which the first edge 211 of the first surface 21 extends. A first virtual line Y1 passing through the center of the first via conductor 35 and along the first direction, and a second virtual line Y2 passing through the center of the second via conductor 45 and along the first direction, are spaced apart from each other. The first electrode 30 is partially covered by the insulating layer 60. The second electrode 40 has a gap between it and the insulating layer 60 in a planar view. In other words, the second electrode 40 is not covered by the insulating layer 60.

[0012] As shown in Figure 3, in the wiring board 10 of one embodiment of the present disclosure, the first virtual line Y1 and the second virtual line Y2 are positioned with a gap between them, as described above. In other words, the positions of the first via conductor 35 and the second via conductor 45 are different in the second direction (the Y-axis direction in the drawing) which is perpendicular to the first direction (the X-axis direction in the drawing). In a wiring board 10 having such a configuration, the gap between the first via conductor 35 and the second via conductor 45 can be shortened, thereby making the wiring board 10 relatively compact. This is because, compared to simply shortening the gap between via conductors that are aligned in the first direction and whose positions in the second direction are aligned, there are the following advantages. That is, in the wiring board 10 of this embodiment, when the gap between the first via conductor 35 and the second via conductor 45 is shortened, it is easier to ensure the strength of the base 25, it is easier to reduce the possibility of short circuits, and it is easier to reduce noise.

[0013] Here, in the wiring board 10, the first electrode 30 and the second electrode 40 each have a region for electrical connection with the electronic element 2. Hereinafter, this region may be referred to as the connection region. In the connection region, for example, a bonding wire 3 is connected to the electrode. Therefore, the first electrode 30 and the second electrode 40 each have a connection region of a certain size (which may be rephrased as area). The first electrode 30 and the second electrode 40 are aligned on the first surface 21 and are connected to the first via conductor 35 and the second via conductor 45, respectively, which are in the positional relationship described above. The second electrode 40 has a gap between it and the insulating layer 60. On the other hand, the first electrode 30 is provided such that a part of it is covered by the insulating layer 60. Therefore, in the second direction, the first electrode 30 extends longer than the second electrode 40, while ensuring that the connection regions of the same size are maintained between the first electrode 30 and the second electrode 40.

[0014] Generally, with relatively long electrodes, compared to relatively short electrodes, warping of the electrodes during substrate manufacturing can occur, potentially resulting in unevenness or inclination due to the warping of the electrodes. If there is a large difference in height of the connection area between different electrodes, or if there is a difference in the flatness of the connection area, the stability of the connection may decrease when, for example, the bonding wire 3 is connected to the connection area.

[0015] In the wiring board 10, a portion of the first electrode 30 is covered with an insulating layer 60, which makes it difficult to cause warping of the first electrode 30 during the manufacturing of the board. Also, the height difference within the first electrode 30 can be reduced compared to when the first electrode 30, which is longer in the second direction than the second electrode 40, is not covered with the insulating layer 60. Therefore, in the wiring board 10, the height difference within the first electrode 30 can be made closer to the height difference within the second electrode 40. Note that the warping of the electrodes and the height difference within the material may be controlled by flatness measurement. The first electrode 30 has a connection region in the portion not covered with the insulating layer 60. On the other hand, the second electrode 40 consists only of the portion not covered with the insulating layer 60, and has a connection region in that portion. The connection region of the first electrode 30 and the connection region of the second electrode 40 are aligned in the first direction, and their positions in the second direction can be made the same. Therefore, while making the length or area of ​​the connection regions of the first electrode 30 and the second electrode 40 roughly the same, it is possible to reduce the possibility of height differences occurring between the respective connection regions of the first electrode 30 and the second electrode 40, as well as the possibility of differences in flatness. Thus, it is possible to provide a wiring board 10 that can mount the electronic element 2 more stably.

[0016] Hereinafter, a wiring board 10 in one embodiment of the present disclosure will be further described with reference to Figures 1 to 5.

[0017] (Substrate) The substrate 20 may be an insulating substrate (a so-called insulating substrate). The base 25 and insulating layer 60 on the substrate 20 may be made of insulating materials. Examples of insulating materials that can be used include ceramic materials such as aluminum oxide (alumina), silicon oxide, and aluminum nitride, epoxy resins, polyimide resins, olefin resins, polyphenylene resins, organic resin materials such as polytetrafluoroethylene (PTFE), glass materials, etc. The insulating layer 60 may be made of the same material as the base 25, may contain the same material as the base 25, may contain a different material from the base 25, or may be made of a different material from the base 25.

[0018] In one embodiment, the base body 25 has a rectangular parallelepiped shape and has a first face 21, a second face 22 facing the first face 21, and four side surfaces 23. The specific shape of the base body 25 is not particularly limited. In the base body 25 in this embodiment, the side surfaces 23 are planes perpendicular to the first face 21, but are not limited to this, and the side surfaces 23 may be planes inclined with respect to the first face 21. The side surfaces 23 may have irregularities.

[0019] In one embodiment, the insulating layer 60 covers most of the first surface 21 of the substrate 25. Since the insulating layer 60 is located on the first surface 21 and constitutes a part of the surface of the substrate 20, it can also be called a surface insulating layer. In this disclosure, "most of" means 65% or more of the area of ​​the first surface 21.

[0020] In the example shown in Figure 1, the insulating layer 60 has four openings 65 that penetrate to the first surface 21. Each opening 65 extends in the vicinity of each of the four sides of the first surface 21 in a direction along that side. The insulating layer 60 may be provided in contact with each of the four sides of the first surface 21 in a plan view. In the example shown in Figure 1, the insulating layer 60 is located continuously at the four corners of the first surface 21, in other words, there are no openings 65 at each corner. The portion of the first surface 21 that overlaps with the electronic element 2 in a plan view may be covered by the insulating layer 60.

[0021] The thickness of the insulating layer 60 may be, for example, within the range of 0.005 mm to 0.040 mm. In this specification, the thickness of a certain member is interpreted in a general sense, without considering the change in thickness at the edge of the member in a plan view. Specifically, it is as follows: In this specification, the region where a member having a designed thickness (e.g., the insulating layer 60) is intended to be formed, and where the thickness of the member after formation is not expected to fluctuate significantly, is referred to as the constant thickness region. However, if it is difficult to measure the thickness in the constant thickness region for a certain member, the thickness of the region with a thickness greater than the constant thickness region may be taken as the thickness of that member. Also, if there is no constant thickness region, the thickness of a certain member may mean the maximum thickness. The thickness of the insulating layer 60 refers to the thickness in the constant thickness region. In the case of a certain member, if the edge in a plan view has a shape in which the thickness gradually decreases toward the outside of the member, the gradually decreasing thickness at the edge is not considered when referring to the thickness of that member. Hereinafter, such a thickness that changes at the edge may be referred to as the edge thickness.

[0022] The thickness of the insulating layer 60 in the portion of the constant-thickness region that covers a part of the first electrode 30 may be expressed by the distance in the third direction from the surface of the first electrode 30 to the surface of the insulating layer 60. The thickness of the insulating layer 60 in the portion of the constant-thickness region that does not cover a part of the first electrode 30 may be expressed by the distance in the third direction from the surface of the first surface 21 to the surface of the insulating layer 60. In this specification, the distance in the third direction from the first surface 21 to the surface of the insulating layer 60 in any portion of the constant-thickness region of the insulating layer 60, regardless of whether or not it covers a part of the first electrode 30, is expressed as the height of the insulating layer 60.

[0023] The thickness of the insulating layer 60 may vary within the constant thickness region, in which case the varying thickness within the constant thickness region should be within the range of 0.005 mm to 0.040 mm. The variation in thickness within the constant thickness region is distinct from the edge thickness. The edge of the insulating layer 60 may be a portion of the insulating layer 60 that, in a plan view, extends from the outer edge of the insulating layer 60 toward the inside of the insulating layer 60 by, for example, about 20 μm, or a portion that extends by about 150 μm. Alternatively, the edge of the insulating layer 60 may be a portion of the insulating layer 60 that, in a plan view, extends from the outer edge of the insulating layer 60 toward the inside of the insulating layer 60 by, for example, a numerical value within the range of 20 to 150 μm, depending on the shape of the edge of the insulating layer 60.

[0024] For measuring thickness, any known method may be used as appropriate, for example, a contact-type or non-contact-type measurement method can be used. An example of a contact-type measurement method is clamping with calipers. Examples of non-contact-type measurement methods include infrared-type, radiation-type, and laser displacement sensor-type measurement methods. When measuring and comparing the thickness of multiple components, it is sufficient to consistently use a specific measurement method (and measurement conditions) to compare the measured thickness of each component. Furthermore, if the thickness of multiple different components constituting the wiring board 10 is not measured and compared, the measurement method for each component may be different. The same applies to thickness in the following explanation, and a repeated explanation will be omitted.

[0025] As shown in Figures 1, 4, and 5, the insulating layer 60 has an end face 60F surrounding the opening 65. The opening 65 of the insulating layer 60 may have a longitudinal shape with the first direction as the longitudinal direction. The end face 60F includes a first end face 60F1 located on the side closer to the first side 211 and a second end face 60F2 located on the side further from the first side 211 (in other words, on the side closer to the center of the wiring board 10). The first end face 60F1 and the second end face 60F2 may each extend along the first side 211, that is, they may extend along the first direction. The first end face 60F1 and the second end face 60F2 may each be planar or curved.

[0026] In one embodiment of the wiring board 10 of this disclosure, the insulating layer 60 and the substrate 25 may be integrally formed with each other. This improves the strength of the wiring board 10. When manufacturing the wiring board 10, the insulating layer 60 can be formed integrally with the substrate 25 on the first surface 21 of the substrate 25, having an opening 65 and covering a part of the first electrode 30. For example, if the wiring board 10 is an organic printed circuit board, the insulating layer 60 may be solder resist, and the solder resist may be integrated with the resin substrate 25. Also, if the wiring board 10 is a ceramic substrate, the insulating layer 60 and the substrate 25 may be integrated by firing during manufacturing. An example in which the wiring board 10 is a ceramic substrate will be described in detail later. In this specification, when two members are said to be integrally formed with each other, it means that the interface between the two members cannot be observed by a microscope or the like.

[0027] (Electrodes) The first electrode 30 and the second electrode 40 may be made of a conductive material. Known materials may be used as the conductive material. The first electrode 30 and the second electrode 40 may contain at least one of gold, silver, and copper, which can effectively reduce the resistance of the first electrode 30 and the second electrode 40. This is because gold, silver, and copper have lower resistance values ​​than other metallic materials.

[0028] The thicknesses of the first electrode 30 and the second electrode 40 may be within the range of 0.005 mm to 0.040 mm. The electrode thickness refers to the thickness in the constant thickness region described above. The thickness of the first electrode 30 and the thickness of the second electrode 40 may be the same as each other. The thickness of the first electrode 30 may be greater than the thickness of the second electrode 40. The first electrode 30 and the second electrode 40 may have edges having the edge thickness described above. The edge of the first electrode 30 may be a portion of the first electrode 30 that, in a plan view, extends from the outer edge of the first electrode 30 toward the inside of the first electrode 30 by, for example, about 1 μm, or a portion that extends by about 20 μm. Alternatively, the edge of the first electrode 30 may be a portion of the first electrode 30 that, in a plan view, extends from the outer edge of the first electrode 30 toward the inside of the first electrode 30 by, for example, a numerical value within the range of 1 to 20 μm, depending on the size of the first electrode 30 and the shape of the edge. The edge of the second electrode 40 may be a portion of the second electrode 40 that extends inward from the outer edge of the second electrode 40 in a plan view, for example, by about 1 μm, or it may be a portion that extends inward by about 20 μm. Alternatively, the edge of the second electrode 40 may be a portion of the second electrode 40 that extends inward from the outer edge of the second electrode 40 in a plan view, for example, by a numerical value within a range of 1 to 20 μm, depending on the size of the second electrode 40 and the shape of the edge.

[0029] The first electrode 30 has a covered portion 31 that is covered by an insulating layer 60 and an exposed portion 32 that is not covered by the insulating layer 60. In one embodiment of the wiring board 10, the exposed portion 32 of the first electrode 30 and the entire portion of the second electrode 40 are positioned in a first direction within one opening 65. In the wiring board 10, there are no other electrodes between adjacent first electrodes 30 and second electrodes 40. A metal film may be formed on the surface of the exposed portion 32 and the second electrode 40, and even in this case, it is said that the exposed portion 32 and the second electrode 40 are exposed within the opening 65. In other words, the exposure of the exposed portion 32 and the second electrode 40 within the opening 65 means that the insulating layer 60 is not located above the exposed portion 32 and the second electrode 40 within the opening 65.

[0030] As shown in Figure 3, in one embodiment, the first electrode 30 may have a rounded rectangular shape with the second direction as its longitudinal direction in a plan view. The first electrode 30 may include a first base portion 30A extending in the second direction and a first land portion 30B connected to the first via conductor 35. The first land portion 30B is connected to the upper end of the first via conductor 35 and is positioned surrounding the first via conductor 35 in a plan perspective view.

[0031] The first electrode 30 has ends 30E on both sides in the second direction. The end 30E closer to the first side 211 is referred to as the first outer end 30EO, and the other end 30E (the end 30E closer to the center of the wiring board 10) is referred to as the first inner end 30EI. In a plan view, the outer edge of the first outer end 30EO of the first electrode 30 may be curved (for example, an arc shape), and the outer edge of the first inner end 30EI may be curved (for example, an arc shape).

[0032] In one embodiment, the first electrode 30 has a first land portion 30B connected to the end of the first base portion 30A, which is located on the opposite side from the first inner end portion 30EI. In one embodiment, the first land portion 30B includes a first outer end portion 30EO, and a part of the first land portion 30B is a covering portion 31. The first outer end portion 30EO may be covered by an insulating layer 60, in which case the covering portion 31 includes the first outer end portion 30EO. Not limited to the examples shown in Figures 3 and 4, in one embodiment the first base portion 30A may be a rectangular portion in plan view, in which case the outer edge of the first inner end portion 30EI may be a straight line.

[0033] In one embodiment, the second electrode 40 may have a rounded rectangular shape with the second direction as its longitudinal direction in a plan view. The second electrode 40 may include a second base portion 40A extending in the second direction and a second land portion 40B connected to the second via conductor 45. The second land portion 40B is connected to the upper end of the second via conductor 45 and is positioned surrounding the second via conductor 45 in a plan view.

[0034] The second electrode 40 has two ends 40E in the second direction. The end 40E closer to the first side 211 is called the second outer end 40EO, and the other end 40E (the end 40E closer to the center of the wiring board 10) is called the second inner end 40EI. In a plan view, the outer edge of the second outer end 40EO of the second electrode 40 may be curved (for example, an arc shape), and the outer edge of the second inner end 40EI may be curved (for example, an arc shape).

[0035] In one embodiment, the second electrode 40 has a second land portion 40B connected to the end of the second base portion 40A, which is located on the opposite side from the second inner end portion 40EI. In one embodiment, the second land portion 40B includes a second outer end portion 40EO. In a plan view, the wiring board 10 has a gap between the second inner end portion 40EI and the insulating layer 60 (second end face 60F2), and a gap between the second outer end portion 40EO and the insulating layer 60 (first end face 60F1). Not limited to the examples shown in Figures 3 and 5, in one embodiment, the second base portion 40A may be a rectangular portion in a plan view, in which case the outer edge of the second inner end portion 40EI may be straight.

[0036] In the wiring board 10, the first inner end 30EI of the first electrode 30 and the second inner end 40EI of the second electrode 40 are aligned in the first direction, and their positions in the second direction may be the same. Furthermore, in the wiring board 10, the first outer end 30EO of the first electrode 30 and the second outer end 40EO of the second electrode 40 are aligned in the first direction, and in the second direction, the first outer end 30EO is closer to the first side 211 than the second outer end 40EO. In other words, in the second direction, the first electrode 30 has a longer shape than the second electrode 40. Note that the positions of the first inner end 30EI and the second inner end 40EI being the same in the second direction means that they are substantially the same, and a positional difference of 30 μm or less in the second direction is permitted.

[0037] The wiring board 10 may have the same distance between the first inner end 30EI and the second end face 60F2, and the same distance between the second inner end 40EI and the second end face 60F2. The two distances being the same means they are substantially the same, and a difference of 30 μm or less between the two distances is permitted.

[0038] In one embodiment of the present disclosure, the wiring board 10 may have a longitudinal shape extending from the first via conductor 35 (in other words, the first land portion 30B) in a direction away from the first side 211 of the first surface 21 in a second direction perpendicular to the first direction. The second electrode 40 may have a longitudinal shape extending from the second via conductor 45 (in other words, the second land portion 40B) in a direction away from the first side 211 in the second direction. The first electrode 30 and the second electrode 40 may each have portions extending from the first via conductor 35 and the second via conductor 45 in a direction approaching the first side 211.

[0039] In the wiring board 10, a first metal film 71 is located on the exposed portion 32 of the first electrode 30, and a second metal film 72 is located on the second electrode 40. The first metal film 71 and the second metal film 72 may contain the same metal material. Having the first metal film 71 and the second metal film 72 makes it easier to increase the durability of the first electrode 30 and the second electrode 40. In addition, in the wiring board 10, a connection area for connecting the bonding wire 3 is located within the opening 65. For example, if the first metal film 71 and the second metal film 72 have a glossy finish, it is easier to automatically detect the connection area when connecting the bonding wire 3 onto the first metal film 71 and the second metal film 72.

[0040] The first metal film 71 and the second metal film 72 may be, for example, plating films. The plating film may contain, for example, tungsten, molybdenum, or nickel as a main component. The plating film may contain at least one of gold, silver, and copper as a main component. The plating film may have a multilayer structure. The uppermost plating film may contain at least one of gold, silver, and copper as a main component, whereby it is easy to enhance the glossiness of the first metal film 71 and the second metal film 72.

[0041] The thicknesses of the first metal film 71 and the second metal film 72 may be within the range of 0.3 μm or more and 10.0 μm or less.

[0042] After forming the first electrode 30, the second electrode 40, and the insulating layer 60, the first metal film 71 and the second metal film 72 may be formed. On the wiring substrate 10, the first metal film 71 may be located on the exposed portion 32, while the first metal film 71 may not be located on the covering portion 31.

[0043] The wiring substrate 10 may include, for example, a back surface electrode 90 located on the second surface 22 of the base body 25. The back surface electrode 90 may be a terminal for electrically connecting to an electrode of an external device, or may be a terminal for electrically connecting to a metal substrate having a ground potential. The electrode of the external device may be, for example, a mounting electrode of a printed circuit board. The back surface electrode 90 may be composed of a conductive material. The back surface electrode 90 may be a part of LGA (Land Grid Array) or PGA (Pin Grid Array) on the second surface 22 of the base body 25. The back surface electrode 90 may be a part of the electrode when the wiring substrate 10 is an LCC (Leadless Chip Carrier).

[0044] (Via Conductor) The first via conductor 35 and the second via conductor 45 are located within the base body 25 and may be composed of a conductive material. The first via conductor 35 and the second via conductor 45 may extend, for example, in the vertical direction (i.e., the thickness direction) within the base body 25.

[0045] As shown in FIGS. 4 and 5, the wiring board 10 may include a first back electrode 91 and a second back electrode 92 as back electrodes 90 located on the second surface 22 of the substrate 25, for example. Hereinafter, for convenience of explanation, the side surface 23 located on the positive Y-axis side (the right side in FIG. 2) among the four side surfaces 23 of the substrate 25 is referred to as the first side surface 23A.

[0046] The upper end of the first via conductor 35 may be connected to the first land portion 30B of the first electrode 30, and the lower end may be electrically connected to the first back electrode 91. The cross-sectional shape of the first via conductor 35 in a plane perpendicular to the vertical direction may be circular. The first via conductor 35 may contain the same material as the first electrode 30 or may not. The distance between the first via conductor 35 and the first side surface 23A may be, for example, 0.20 mm or more and 2.00 mm or less.

[0047] The upper end of the second via conductor 45 may be connected to the second land portion 40B of the second electrode 40, and the lower end may be electrically connected to the second back electrode 92. The cross-sectional shape of the second via conductor 45 in a plane perpendicular to the vertical direction may be circular. The second via conductor 45 may contain the same material as the second electrode 40 or may not. The distance between the second via conductor 45 and the first side surface 23A may be, for example, 0.20 mm or more and 2.00 mm or less. However, in the wiring board 10, in a plan view, the distance between the second via conductor 45 and the first side surface 23A is larger than the distance between the first via conductor 35 and the first side surface 23A.

[0048] In the wiring board 10, the distance (linear distance) between the first via conductor 35 and the second via conductor 45 is larger than the distance D1 in the first direction between the center line extending in the second direction of the first electrode 30 (corresponding to, for example, line IV-IV in FIG. 3) and the center line extending in the second direction of the second electrode 40 (corresponding to, for example, line V-V in FIG. 3). The distance D1 may be, for example, 0.10 mm or more and 0.50 mm or less. Also, in the wiring board 10, the distance between the first virtual line Y1 and the second virtual line Y2, in other words, the distance D2 in the second direction between the first via conductor 35 and the second via conductor 45 may be, for example, 0.10 mm or more and 0.40 mm or less.

[0049] The distance between the first via conductor 35 and the second via conductor 45 may be, for example, 0.05 mm or more and 0.15 mm or less. The distance between the first electrode 30 and the second electrode 40 may be, for example, 0.02 mm or more and 0.10 mm or less.

[0050] (Electronic Elements) The electronic elements 2 are mounted, for example, on the insulating layer 60 of the substrate 20. The electronic elements 2 may be mounted on the insulating layer 60 by joining them via a bonding material such as brazing material, glass, or adhesive, or they may be mounted indirectly on the insulating layer 60 via a member such as a base. The electronic elements 2 may be semiconductor elements, piezoelectric elements, sensor elements, passive elements, etc., and may be, for example, CCD (Charge-Coupled Device) elements, CMOS (Complementary Metal-Oxide Semiconductor) elements, etc. The electronic elements 2 may also be display elements such as liquid crystal displays. Multiple electronic elements 2 of multiple types may be mounted on the electronic module 1.

[0051] (Configuration Example) As shown in Figure 4, in the wiring board 10 of one embodiment of the present disclosure, the maximum thickness T1 of the insulating layer 60 may be greater than or equal to the maximum thickness T2 of the first electrode 30. This reduces the possibility that some other component may come into contact with the first electrode 30 in various situations. Therefore, the possibility of damage occurring to the first electrode 30 due to contact with other components can be effectively reduced.

[0052] The "maximum thickness T1" of the insulating layer 60 is obtained as a measured distance from the first surface 21 to the uppermost edge of the insulating layer 60 in the thickness direction. The "maximum thickness T2" of the first electrode 30 is obtained as a measured distance from the first surface 21 to the uppermost edge of the first electrode 30 in the thickness direction. Thus, the "maximum thickness T1" of the insulating layer 60 may be the aforementioned maximum height of the insulating layer 60. In this specification, the "maximum thickness T1" of the insulating layer 60 covering the first electrode 30 may include the thickness of the insulating layer 60 plus the thickness of the first electrode 30.

[0053] The maximum thickness T1 of the insulating layer 60 may be in the range of 0.005 mm or more and 0.040 mm or less. The maximum thickness T2 of the first electrode 30 may be in the range of 0.005 mm or more and 0.040 mm or less. If the surface of the exposed portion 32 has a first metal film 71, the thickness of the first metal film 71 is not added to the maximum thickness T2 of the first electrode 30.

[0054] As shown in Figure 5, the maximum thickness T3 of the second electrode 40 may be about the same as the maximum thickness T2 of the first electrode 30. The maximum thickness T1 of the insulating layer 60 may be greater than or equal to the maximum thickness T2 of the first electrode 30 and greater than or equal to the maximum thickness T3 of the second electrode 40. This effectively reduces the possibility of damage occurring to either the first electrode 30 or the second electrode 40 due to contact with other components, etc.

[0055] The maximum thickness T3 of the second electrode 40 is obtained as a measurement of the distance from the first surface 21 to the uppermost end of the second electrode 40 in the thickness direction. The maximum thickness T3 of the second electrode 40 may be in the range of 0.005 mm or more and 0.040 mm or less. If the second electrode 40 has a second metal film 72 on its surface, the thickness of the second metal film 72 is not added to the maximum thickness T3 of the second electrode 40.

[0056] As shown in Figure 3 and other figures, in the wiring board 10 of one embodiment of the present disclosure, the second electrode 40 may be sandwiched between the insulating layer 60 with a gap in a second direction perpendicular to the first direction. That is, the second electrode 40 may have a gap between the second inner end 40EI and the second end face 60F2 of the insulating layer 60, and a gap between the second outer end 40EO and the first end face 60F1 of the insulating layer 60. This protects the second electrode 40 without it being covered by the insulating layer 60. Therefore, the possibility of any other component coming into contact with the second electrode 40 in various situations can be reduced. As a result, the possibility of damage to the second electrode 40 due to contact with other components can be effectively reduced. Furthermore, the possibility of connection failure due to interference between the insulating layer 60 and the connection portion when connecting the electrode of the electronic element 2 and the second electrode 40 can be reduced.

[0057] In the wiring board 10, since bonding wires 3 need to be routed from the electrodes of the electronic element 2 to the connection area located within the opening 65, a certain distance is required between the electrodes of the electronic element 2 and the connection area. The distance from the second inner end 40EI to the second end face 60F2 may be greater than the distance from the second outer end 40EO to the first end face 60F1. This makes it easier to connect the bonding wires 3, etc., to the second electrode 40. Furthermore, by forming the insulating layer 60 with the above configuration, the distance from the ends of the first electrode 30 and the ends of the second electrode 40 to the second end face 60F2 becomes relatively far, and as a result, it becomes easier to secure the connection areas of the first electrode 30 and the second electrode 40, respectively.

[0058] As shown in Figure 4, etc., in the wiring board 10 of one embodiment of the present disclosure, the diameter of the first land portion 30B and the width of the first base portion 30A may be the same. Also, the diameter of the second land portion 40B and the width of the second base portion 40A may be the same. The width of the first base portion 30A and the width of the second base portion 40A refer to the length in the first direction. With this configuration, even if blurring or manufacturing misalignment occurs of the first electrode 30 and the second electrode 40 when the wiring board 10 is miniaturized, the first electrode 30 and the second electrode 40 are less likely to come into contact with each other.

[0059] In one embodiment of the present disclosure, the wiring board 10 may be located away from the first side surface 23A. With this configuration, when manufacturing the wiring board 10 by dividing a multi-cavity substrate, it is easier to form dividing grooves by dicing, laser, etc. Furthermore, when forming the first electrode 30 and the second electrode 40, the possibility of the material forming the first electrode 30 and the second electrode 40 dripping onto the first side surface 23A can be reduced. Moreover, with this configuration, even if conductive material adheres to the portion where the first side surface 23A and the first surface 21 intersect, the possibility of the first electrode 30 and the second electrode 40 being electrically connected by the conductive material can be reduced.

[0060] In one embodiment of the present disclosure, the wiring board 10 may be manufactured, for example, by firing an insulating material. For example, it may have a structure in which multiple insulating materials are laminated. The substrate 20 may be, for example, a ceramic substrate, and is typically manufactured by firing a precursor formed by combining an insulating ceramic material and a metal material for wiring. In this case, the base body 25 and the insulating layer 60 are integrated with each other. The precursor may be a laminate. Furthermore, both the material of the insulating layer 60 and the material of the base body 25 may contain ceramic. This can improve the rigidity and strength of the substrate 20. It can also improve the heat dissipation of the substrate 20.

[0061] Hereinafter, when the substrate 20 is a ceramic substrate, the insulating layer inside the substrate 20 will be referred to as the substrate insulating layer to distinguish it from the insulating layer (surface insulating layer) 60.

[0062] The wiring board 10 may have conductor layers (so-called internal wiring) between a plurality of substrate insulating layers. One or more via conductors may be provided in each substrate insulating layer, and the one or more via conductors located in each substrate insulating layer may be positioned differently from each other in a planar view from above. Wiring conductors connecting the via conductors may be provided between two adjacent substrate insulating layers. For example, the first via conductor 35 may be connected to the first back electrode 91 via one or more wiring conductors and one or more via conductors. The second via conductor 45 may be connected to the second back electrode 92 via one or more wiring conductors and one or more via conductors.

[0063] In the substrate 20, multiple substrate insulating layers after firing may be integrally connected when stacked with each other. Therefore, it is difficult to determine whether or not they were stacked before firing, or to directly identify individual substrate insulating layers that were stacked before firing from the substrate 20. However, the conductive layer can be confirmed even after firing. Therefore, for the substrate 20 after firing, it is possible to confirm (detect) the presence of substrate insulating layers above and below the conductive layer based on the position of the conductive layer.

[0064] In the wiring board 10, the thickness of the substrate insulating layer may be 0.03 mm to 0.60 mm. The thickness of the substrate insulating layer may be greater than the thickness of the insulating layer 60.

[0065] The first electrode 30 and the second electrode 40 may contain metals with relatively high melting points, such as tungsten and molybdenum. The first electrode 30 and the second electrode 40 may also contain glass material. If the substrate 20 is made of ceramic and manufactured by firing at a high temperature, making the melting points of the first electrode 30 and the second electrode 40 relatively high can reduce the possibility of the first electrode 30 and the second electrode 40 melting during firing. The first via conductor 35 and the second via conductor 45 may contain metals with low resistance, such as copper. By lowering the resistance of the first via conductor 35 and the second via conductor 45, the resistance in power and signal input and output on the wiring board 10 can be lowered.

[0066] The first via conductor 35 and the second via conductor 45 may contain, for example, metals with high melting points such as tungsten and molybdenum. When the substrate 20 is made of ceramic and manufactured by firing at high temperatures, making the melting points of the first via conductor 35 and the second via conductor 45 relatively high can reduce the possibility of problems occurring where the first via conductor 35 and the second via conductor 45 melt during firing.

[0067] As shown in Figures 1 to 5, in one embodiment of the present disclosure, the wiring board 10 may have multiple sets of first electrodes 30 and second electrodes 40 along the first side surface 23A of the substrate 20 on the first surface 21. In Figure 1, three first electrodes 30 and three second electrodes 40 are shown for clarity, but the number of first electrodes 30 and second electrodes 40 in the wiring board 10 is not particularly limited. The wiring board 10 has a plurality of first via conductors 35 and a plurality of second via conductors 45 corresponding to each first electrode 30 and each second electrode 40. Each first electrode 30 is electrically connected to one of the plurality of first via conductors 35, and each second electrode 40 is electrically connected to one of the plurality of second via conductors 45.

[0068] Furthermore, the examples shown in Figures 1 to 5 are not limited to the present invention. Multiple sets of first electrodes 30 and second electrodes 40 may be arranged along each of the four sides 23 of the substrate 20. Multiple sets of first electrodes 30 and multiple sets of second electrodes 40 may be electrically connected to any of the electrodes of the electronic element 2 by bonding wires 3. Alternatively, multiple sets of first electrodes 30 and multiple sets of second electrodes 40 may be electrically connected to any of the electrodes of the electronic element 2 by conductive materials such as solder, brazing material, or conductive resin.

[0069] Figure 6 is a partial plan view of an electronic module in another configuration example of Embodiment 1 of this disclosure. Figure 6 shows the same region as in Figure 3 in a plan view. Figure 7 is a cross-sectional view taken along the line VII-VII shown in Figure 6.

[0070] As shown in Figures 6 and 7, in one configuration example, the wiring board 10 may have at least a portion of the first via conductor 35 overlapping with the insulating layer 60 in a planar view. As mentioned above, generally, during the manufacturing of a substrate, there is a possibility of unevenness occurring at the connection points with the via conductors. In contrast, in the example shown in Figures 6 and 7, by having the above configuration, it is possible to make it difficult for the first electrode 30 to warp during the manufacturing of the substrate. By making the volume (area in a planar view) of the covering portion 31 relatively large, it is possible to make it even more difficult for the first electrode 30 to warp. Therefore, while keeping the length (or size) of the connection areas of the first electrode 30 and the second electrode 40 to be about the same, it is possible to reduce the possibility of height differences occurring between the respective connection areas of the first electrode 30 and the second electrode 40, and to reduce the possibility of differences in flatness. Thus, it is possible to provide a wiring board 10 that can mount electronic elements 2 more stably.

[0071] Figure 8 is a perspective view showing the configuration of an electronic module in another configuration example of Embodiment 1 of the present disclosure. As shown in Figure 8, in the wiring board 10 in one configuration example, the board 20 may have a second side 212 extending in a second direction on the first surface 21 and a first outer side 216 connecting the first side 211 and the second side 212, and the insulating layer 60 may be positioned with a gap from the first outer side 216.

[0072] Generally, the corners of a substrate are relatively prone to contact with other components and are susceptible to wear. According to the above configuration, the corners of the base body 25 have a shape in which the first surface 21 has a first outer edge 216, for example, the corners of the base body 25 have notches. This makes it less likely for the corners of the base body 25 to come into contact with other components, and even if contact does occur, it reduces the possibility of large localized stress. Furthermore, according to the above configuration, since the insulating layer 60 is separated from the first outer edge 216, the possibility of damage such as peeling or chipping of the insulating layer 60 can be effectively reduced.

[0073] When mounting the wiring board 10 (electronic module 1) to other components, a bonding material may be used to join the second surface 22 side of the wiring board 10 to the other components. In one example configuration of the wiring board 10, an insulating layer 60 exists at a distance from the first outer edge 216, and since the insulating layer 60 has some thickness, there is a step between the first surface 21 and the surface of the insulating layer 60. Therefore, even if the bonding material were to travel up the side surface of the base 25 that connects to the first surface 21 via the first outer edge 216, the possibility of the bonding material reaching the surface of the insulating layer 60 can be effectively reduced.

[0074] Although not shown in the diagram, in one configuration example, the insulating layer 60 may be provided away from the four sides of the first surface 21 that extend in the first or second direction when viewed in plan. This will produce the same effects as described above.

[0075] The first outer edge 216 may be a straight line or a curved shape. The first outer edge 216 may have a curved shape that is recessed toward the inside of the wiring board 10, in which case the side surface of the base 25 that connects to the first surface 21 via the first outer edge 216 may have a curved shape.

[0076] (Other configuration examples) In one aspect of the present disclosure, the wiring board 10 may have a first electrode 30 extending from a first via conductor 35 toward a first side 211, and a second electrode 40 may have a second via conductor 45 extending toward a first side 211. Alternatively, either the first electrode 30 or the second electrode 40 may extend toward a first side 211, while the other extends toward a direction away from the first side 211.

[0077] In the wiring board 10, it is sufficient that the first electrode 30 and the second electrode 40 within the opening 65 can be electrically connected to the electrodes of the electronic element 2, for example, via bonding wires 3, and the specific form of the opening 65 is not particularly limited. The substrate 25 may be made of various materials and may have various shapes depending on the type of substrate 20. The first electrode 30 may also be called the first conductor, and the second electrode 40 may also be called the second conductor.

[0078] In the electronic module 1, for example, an electronic element 2 may be connected to an electrode pad located on the upper surface of the insulating layer 60 of the wiring board 10 via a conductive bonding material. In this case, the electrode pad and the first electrode 30 or second electrode 40 of the wiring board 10 may be electrically connected by a bonding wire 3.

[0079] [Embodiment 2] Another embodiment of the present disclosure is described below. For the sake of convenience of explanation, components having the same function as those described in the above embodiments are denoted by the same reference numerals, and their descriptions are not repeated.

[0080] Figure 9 is a perspective view showing the configuration of a wiring board in Embodiment 2 of the present disclosure. Figure 10 is a cross-sectional view taken along the line X-X shown in Figure 9. Unlike Figure 1, Figures 9 and 10 show the wiring board 10 before the electronic elements 2 are mounted. In Figure 10, the first via conductor 35 and the second via conductor 45 are shown in planar perspective.

[0081] As shown in Figures 9 and 10, in the wiring board 10 of Embodiment 2 of the present disclosure, the insulating layer 60 has a first portion 61 and a second portion 62 positioned with respect to the first portion 61, sandwiching the second electrode 40. The first portion 61 is located on the outer edge side of the substrate 20. The second portion 62 is located on the central side of the substrate 20 and may be rectangular in shape, for example, in a plan view. The first surface 21 is exposed between the first portion 61 and the second portion 62. In the wiring board 10, a part of the first electrode 30 may be covered by the first portion 61. A first metal film 71 may be formed on the exposed portion 32 of the first electrode 30 (see Figure 4), and a second metal film 72 may be formed on the second electrode 40 (see Figure 5).

[0082] In this embodiment, the wiring board 10 has a first portion 61, which reduces the possibility of the first electrode 30 and the second electrode 40 being damaged by contact objects from outside the board 20. It also reduces the possibility of electrical connection failures with the electronic element 2 caused by contact objects from outside the board 20. Furthermore, the presence of the first portion 61 reduces the possibility of a short circuit between the first electrode 30 and the second electrode 40, or of electrical connection failures between the first electrode 30 or the second electrode 40 and the electronic element 2. This is because it reduces the possibility of dust adhering to the first electrode 30 or the second electrode 40, or dust adhering between the first electrode 30 and the second electrode 40. In addition, the presence of the first portion 61 improves the strength of the edges of the board 20.

[0083] The first portion 61 and the second portion 62 may be made of an insulating material, similar to the insulating layer 60 described above, and the second portion 62 may be made of the same material as the first portion 61 or a different material. The thickness of the second portion 62 may be the same as the thickness of the first portion 61 or a different thickness. The first portion 61 or the second portion 62 may cover the ground conductor.

[0084] The first portion 61 may be provided on the first surface 21 of the base 25 along the outer periphery of the base 25 (the outer edge of the first surface 21). The first portion 61 may be provided in contact with the first side 211 in a plan view, or it may be provided with a gap between it and the first side 211. The first portion 61 may be provided in contact with the outer edge of the first surface 21, or it may be provided with a gap between it and the outer edge of the first surface 21.

[0085] In the example shown in Figure 9, the first outer edge 216 may have a concave shape toward the center of the first surface 21. The first outer edge 216 corresponding to the corner of the base body 25 has a concave shape, and in this case, the side surface of the base body 25 that connects to the first surface 21 via the first outer edge 216 can be curved. This effectively reduces the possibility of damage to the corner of the base body even when it comes into contact with other parts.

[0086] The wiring board 10 has an element mounting area on the second portion 62 for mounting the electronic element 2. In the wiring board 10, the distance D3 between the second electrode 40 and the second portion 62 in the second direction perpendicular to the first direction may be greater than the distance D4 between the second electrode 40 and the first portion 61. With the above configuration, by not bringing the second electrode 40 too close to the element mounting area, it is possible to easily connect bonding wires 3, etc., to the second electrode 40. Also, by moving the second portion 62 away from the respective ends of the first electrode 30 and the second electrode 40, it is possible to easily secure the connection areas of the first electrode 30 and the second electrode 40, respectively. The distance D3 may be, for example, 0.10 mm to 0.40 mm. The distance D4 may be, for example, 0.01 mm to 0.15 mm.

[0087] [Embodiment 3] Another embodiment of the present disclosure is described below. For the sake of convenience of explanation, components having the same function as those described in the above embodiments are denoted by the same reference numerals, and their descriptions are not repeated.

[0088] Embodiments 1 and 2 described above as examples of a wiring board 10 having a generally flat surface for the insulating layer 60. In contrast, Embodiment 3 describes an example of a wiring board 10 having an uneven surface for the insulating layer 60, with varying thickness.

[0089] Figure 11 is an enlarged perspective view showing a part of a wiring board to illustrate the configuration of the wiring board of Embodiment 3 of the present disclosure. Figure 12 is a partial cross-sectional view showing the configuration of the wiring board of Embodiment 3 of the present disclosure. Below, an example in which the insulating layer 60 has a first portion 61 and a second portion 62 (Embodiment 2) will be described. The insulating layer 60 may be formed continuously on the first surface 21 as in Embodiment 1, in which case the first portion 61 and the second portion 62 in the following description should be read as the insulating layer 60.

[0090] As shown in Figures 11 and 12, the first electrode 30 of the wiring board 10 has a covered portion 31 that is covered by the first portion 61 and an exposed portion 32 that is not covered by the first portion 61. In the wiring board 10, the distance D3 between the second electrode 40 and the second portion 62 (second end face 60F2, see Figure 10) in a second direction perpendicular to the first direction may be greater than the distance D4 between the second electrode 40 and the first portion 61 (first end face 60F1, see Figure 10). This makes it easier to connect bonding wires 3, etc., to the second electrode 40. Furthermore, by forming the second portion 62 in the above configuration, the distance from the ends of the first electrode 30 and the ends of the second electrode 40 to the second portion 62 (second end face 60F2) becomes relatively far, and as a result, it is easier to secure the connection area of ​​the first electrode 30 and the second electrode 40, respectively.

[0091] In the wiring board 10 of this embodiment, the first portion 61 has edge portions 69 located on each of the two sides in the second direction, and a main portion 66 located between the two edge portions 69. The main portion 66 can be said to be the portion that performs the function of the first portion 61. For example, the thickness of the first portion 61 may be in the range of 0.005 mm or more and 0.040 mm or less, which means that the thickness of the main portion 66 may be in the range of 0.005 mm or more and 0.040 mm or less. The definition of the edge portion 69 in the first portion 61 is the same as the definition of the edge portion in the insulating layer 60 described above.

[0092] In this embodiment, the wiring board 10 has a portion of the first electrode 30 covered by a first portion 61, and the first portion 61 may have a portion that becomes thinner as it moves away from the first electrode 30 in a second direction perpendicular to the first direction. For convenience of explanation, this portion will be referred to as the thickness-changing portion 662. The main portion 66 of the first portion 61 may have a top portion 661 having a maximum thickness T4 and the thickness-changing portion 662. The main portion 66 may have the aforementioned constant-thickness region. By having the thickness-changing portion 662, the wiring board 10 can increase the intersection angle θ at the intersection 68 between the edge portion 69 of the first portion 61 and the upper surface of the first portion 61. In addition, the curvature around the intersection 68 increases, making the intersection 68 smoother. Therefore, if another member comes into contact with it, the first portion 61 is less likely to chip or peel off. The intersection 68 may also be described as a part of the first surface 21 and the first portion 61.

[0093] As shown in Figures 11 and 12, the height of the portion of the first part 61 located above the covering portion 31 may be greater than the height of the other portions. The top portion 661 may be located above the covering portion 31. On the wiring board 10, the portion of the first part 61 located above the covering portion 31 may be raised by the thickness of the covering portion 31. For example, a paste that will become the insulating layer 60 is applied to the precursor before firing as described above. At this time, the paste that will become the first part 61 is applied to the portion of the first electrode 30 that will become the covering portion 31 and to the portion that will become the substrate insulating layer. This may form the top portion 661. Note that the position of the top portion 661 above the covering portion 31 does not necessarily mean that the top portion 661 is located directly above the covering portion 31, and includes cases where the position of the top portion 661 is shifted by about 1 μm to 600 μm in the X-axis direction or Y-axis direction from directly above the covering portion 31.

[0094] By making the height of the portion of the first part 61 located above the covering portion 31 greater than the height of the other portions, the maximum height of the first part 61 can be increased. Therefore, the possibility of damage occurring to the first electrode 30 and the second electrode 40 due to contact with other components can be reduced even more effectively.

[0095] Figure 13 is a partial cross-sectional view showing the configuration of a wiring board in another configuration example of Embodiment 3 of the present disclosure.

[0096] As shown in Figure 13, in one example of the wiring board 10, a part of the first electrode 30 is covered by the first portion 61, and in a cross-sectional view, the height H1 from the first surface 21 to the vertex of the first portion 61 on the first electrode 30 may be greater than the height H2 from the first surface 21 to the surface of the first portion 61 at a point further away from that vertex in the direction toward the first edge 211.

[0097] In other words, in the main portion 66, the top portion 661 is located above the covering portion 31, and the surface of the thickness-changing portion 662 is lower in the height direction than the apex of the top portion 661. The thickness of the thickness-changing portion 662 may decrease in the direction from the apex of the top portion 661 toward the first side 211, and the thickness-changing portion 662 may have some irregularities and may have parts that are raised compared to the surrounding area. The protruding part in the thickness-changing portion 662 is called the intermediate top portion 663. Thus, the main portion 66 may have intermediate top portions 663 in the thickness-changing portion 662. The height H3 of the intermediate top portion 663 is lower than that of the top portion 661. The main portion 66 may have multiple intermediate top portions 663 in the thickness-changing portion 662. Although the case where the first surface 21 is flat has been described above, if the material of the substrate 20 is ceramic, the first surface 21 is not necessarily flat. Therefore, in the first portion 61, there may be parts where the height of the intermediate apex 663 is higher than the height of the apex 661.

[0098] [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.

[0099] [Summary] The wiring board in embodiment 1 of the present disclosure comprises a substrate having a first surface and an insulating layer located on the first surface, a first electrode located on the first surface, a second electrode located on the first surface and adjacent to the first electrode, and a first via conductor located within the substrate and connected to the first electrode and a second via conductor connected to the second electrode, wherein the first via conductor and the second via conductor are aligned in a planar perspective along a first direction in which the first edge of the first surface extends, a first virtual line passing through the center of the first via conductor and along the first direction and a second virtual line passing through the center of the second via conductor and along the first direction are spaced apart from each other, the first electrode is partially covered by the insulating layer and the second electrode has a gap between it and the insulating layer in a planar view.

[0100] In embodiment 2 of the present disclosure, the wiring board is such that, in embodiment 1, at least a portion of the first via conductor overlaps with the insulating layer in a planar perspective view.

[0101] In embodiment 3 of the present disclosure, the wiring board, in embodiment 1 or 2, has a maximum thickness of the insulating layer that is equal to or greater than the maximum thickness of the first electrode.

[0102] In the wiring board according to embodiment 4 of the present disclosure, in any one embodiment of embodiments 1 to 3, the second electrode is sandwiched between the insulating layers with a gap in a second direction perpendicular to the first direction.

[0103] In embodiment 5 of the present disclosure, the wiring board is such that the insulating layer and the substrate are integrally connected to each other, as in any one embodiment of embodiments 1 to 4.

[0104] In embodiment 6 of the present disclosure, the wiring board, in any one embodiment of embodiments 1 to 5, comprises ceramic material for both the insulating layer and the substrate.

[0105] The wiring board in embodiment 7 of the present disclosure, in any one embodiment of embodiments 1 to 6, has on the first surface a second edge extending in a second direction perpendicular to the first direction and a first outer edge connecting the first edge and the second edge, and the insulating layer is positioned with respect to the first outer edge.

[0106] In embodiment 8 of the present disclosure, the wiring board, in embodiment 7, has a shape in which the first outer edge is recessed toward the center of the first surface.

[0107] In embodiment 9 of the present disclosure, the wiring board, in any one embodiment of embodiments 1 to 8, has an insulating layer comprising a first portion and a second portion positioned with respect to the first portion, the first portion being located on the outer edge side of the board.

[0108] In embodiment 10 of the present disclosure, the wiring board, in embodiment 9, has a portion of the first electrode covered by the first portion, and the first portion has a portion that becomes thinner as it moves away from the first electrode in a second direction perpendicular to the first direction.

[0109] In embodiment 11 of the present disclosure, the wiring board, in embodiment 9 or 10, has a portion of the first electrode covered by the first portion, and in cross-sectional view, the height from the first surface to the vertex of the first portion on the first electrode is greater than the height from the first surface to the surface of the first portion at a location further away from the vertex in the direction toward the first edge.

[0110] In embodiment 12 of the present disclosure, the wiring board is such that, in any one embodiment of embodiments 9 to 11, the distance between the second electrode and the second portion in a second direction perpendicular to the first direction is greater than the distance between the second electrode and the first portion.

[0111] In embodiment 13 of the present disclosure, the wiring board is such that, in any embodiment of embodiments 1 to 12, the first electrode has a longitudinal shape extending from the first via conductor in a direction away from the first side in a second direction perpendicular to the first direction, and the second electrode has a longitudinal shape extending from the second via conductor in a direction away from the first side in the second direction.

[0112] A wiring board in embodiment 14 of the present disclosure, in any one embodiment of embodiments 1 to 13, has a first electrode having a covered portion covered by the insulating layer and an exposed portion not covered by the insulating layer, a first metal film located on the exposed portion and a second metal film located on the second electrode, and the first metal film and the second metal film contain the same metal material.

[0113] The electronic module in embodiment 15 of the present disclosure comprises a wiring board according to any one embodiment of embodiments 1 to 14, and an electronic element electrically connected to the first electrode and the second electrode.

[0114] 1 Electronic module 2 Electronic element 3 Bonding wire 10 Wiring board 20 Substrate 21 First surface 22 Second surface 23 Side 23A First side 25 Base 30 First electrode 30A First base 30B First land 30E End 30EI First inner end 30EO First outer end 31 Covering 32 Exposed 35 First via conductor 40 Second electrode 40A Second base 40B Second land 40E End 40EI Second inner end 40EO Second outer end 45 Second via conductor 60 Insulating layer 60F End face 60F1 First end face 60F2 Second end face 61 First part 62 Second part 65 Opening 66 Main part 68 Intersection 69 Edge 71 First metal film 72 Second metal film 90 Back surface electrode 91 First back surface electrode 92 Second back surface electrode 211 First edge 216 First outer edge 661 Top 662 Changed section 663 Intermediate top Y1 First virtual line Y2 Second virtual line

Claims

1. A wiring board comprising: a substrate having a first surface; an insulating layer located on the first surface; a first electrode located on the first surface; a second electrode located on the first surface and adjacent to the first electrode; and a first via conductor located within the substrate and connected to the first electrode and a second via conductor connected to the second electrode, wherein, in a planar perspective view, the first via conductor and the second via conductor are aligned along a first direction in which the first edge of the first surface extends; a first imaginary line passing through the center of the first via conductor and along the first direction and a second imaginary line passing through the center of the second via conductor and along the first direction are spaced apart from each other; a portion of the first electrode is covered by the insulating layer; and the second electrode has a gap between it and the insulating layer in a planar view.

2. The wiring board according to claim 1, wherein in a planar perspective view, at least a portion of the first via conductor overlaps with the insulating layer.

3. The wiring board according to claim 1 or 2, wherein the maximum thickness of the insulating layer is equal to or greater than the maximum thickness of the first electrode.

4. The wiring board according to any one of claims 1 to 3, wherein the second electrode is sandwiched between the insulating layers with a gap in a second direction perpendicular to the first direction.

5. The wiring board according to any one of claims 1 to 4, wherein the insulating layer and the substrate are integrally formed with each other.

6. The wiring board according to any one of claims 1 to 5, wherein the material of the insulating layer and the material of the substrate both include ceramic.

7. The wiring board according to any one of claims 1 to 6, wherein the substrate has, on the first surface, a second edge extending in a second direction perpendicular to the first direction, and a first outer edge connecting the first edge and the second edge, and the insulating layer is positioned at a distance from the first outer edge.

8. The wiring board according to claim 7, wherein the first outer edge has a shape that is recessed toward the center of the first surface.

9. The wiring board according to any one of claims 1 to 8, wherein the insulating layer has a first portion and a second portion positioned with respect to the first portion, the first portion being located on the outer edge side of the substrate.

10. The wiring board according to claim 9, wherein a portion of the first electrode is covered by the first portion, and the first portion has a portion that becomes thinner as it moves away from the first electrode in a second direction perpendicular to the first direction.

11. The wiring board according to claim 9 or 10, wherein a portion of the first electrode is covered by the first portion, and in cross-sectional view, the height from the first surface to the vertex of the first portion on the first electrode is greater than the height from the first surface to the surface of the first portion at a point further away from the vertex towards the first edge.

12. The wiring board according to any one of claims 9 to 11, wherein in a second direction perpendicular to the first direction, the distance between the second electrode and the second portion is greater than the distance between the second electrode and the first portion.

13. The wiring board according to any one of claims 1 to 12, wherein the first electrode has a longitudinal shape extending from the first via conductor in a direction away from the first side in a second direction perpendicular to the first direction, and the second electrode has a longitudinal shape extending from the second via conductor in a direction away from the first side in the second direction.

14. The wiring board according to any one of claims 1 to 13, wherein the first electrode has a covered portion covered by the insulating layer and an exposed portion not covered by the insulating layer, a first metal film is located on the exposed portion, a second metal film is located on the second electrode, and the first metal film and the second metal film contain the same metal material.

15. An electronic module comprising a wiring board according to any one of claims 1 to 14, and an electronic element electrically connected to the first electrode and the second electrode.

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