Wiring board, package, and electronic device

Abstract

The present invention improves the flatness of an upper part of a frame part. This wiring board comprises a base part, a frame part, a metallized layer positioned on the upper surface of the frame part, an in-frame conductor positioned inside the frame part, and a relay conductor positioned inside the base part. The in-frame conductor has a first portion that extends adjacent to the metallized layer, inward from the outer edge of the frame part, and a second portion that connects the first portion and the relay conductor.

Description

Wiring board, package, and electronic device

[0001] The present disclosure relates to a wiring board, a package, and an electronic device.

[0002] Patent Document 1 discloses a package for housing electronic components. The package for housing electronic components includes an insulating substrate, a lid body, an electrical wiring structure, etc. The insulating substrate has a plate-shaped first conductor portion inside a frame portion.

[0003] In recent years, thinning of such packages for housing electronic components has been desired.

[0004] WO2019 / 131866

[0005] A wiring board according to an aspect of the present disclosure includes a base having a first surface and a second surface located opposite to the first surface, a frame portion located at an outer edge of the first surface, a metallized layer located on an upper surface of the frame portion, an in-frame conductor located inside the frame portion, and a relay conductor located inside the base. The in-frame conductor has a first portion extending adjacent to the metallized layer inward from an outer edge of the frame portion, and a second portion connecting the first portion and the relay conductor.

[0006] A package according to an aspect of the present disclosure includes the above wiring board and a lid body.

[0007] An electronic device according to an aspect of the present disclosure includes the above package and an electronic component.

[0008] Exploded perspective view of a piezoelectric device according to Embodiment 1. Perspective view of the piezoelectric device according to Embodiment 1 as viewed from below. Top view of the wiring board according to Embodiment 1. Bottom view of the wiring board according to Embodiment 1. Cross-sectional view taken along line V-V in FIG. 3. Cross-sectional view taken along line VI-VI in FIG. 3. Cross-sectional view taken along line VII-VII in FIG. 3. Enlarged view of region R in FIG. 6. Top view of another aspect of the wiring board. Partial cross-sectional view of the wiring board showing another aspect of the in-frame conductor. Partial cross-sectional view of the wiring board showing another aspect of the in-frame conductor. Partial cross-sectional view of the wiring board showing another aspect of the in-frame conductor. Partial cross-sectional view of the wiring board showing another aspect of the frame portion and the in-frame conductor.

[0009] In an electronic component housing package, the lid is bonded to the insulating substrate via a metallized layer located on the upper part of the frame and a bonding material (sealing brazing material).

[0010] As packages become lower in height, the conductor inside the frame may push up the metallized layer above the frame. This pushing-up occurs because, as the frame becomes lower, the stress at which the conductor inside the frame connects to the metallized layer is not sufficiently relieved, or the stress at which the conductor inside the frame connects to the metallized layer becomes smaller. When this pushing-up occurs, the flatness of the upper part of the frame deteriorates, which may affect the airtight seal provided by the lid.

[0011] According to one aspect of this disclosure, the flatness of the upper part of the frame can be improved.

[0012] [Embodiment 1] A wiring board, package, and piezoelectric device according to the first embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. The piezoelectric device is an example of an electronic device according to the present disclosure.

[0013] The distinction between "up" and "down" in the following description is for convenience only and does not limit the actual orientation of the wiring board, package, and piezoelectric device when they are used. In this specification, the side of the wiring board on which the piezoelectric vibrator is mounted is defined as the top surface. Also, in the drawings, the positive Z-axis direction is defined as the up direction. The X-axis direction is the long axis direction of the wiring board, and the Y-axis is the axis perpendicular to the X and Z axes. Also, the Z-axis direction is defined as the thickness direction of the wiring board.

[0014] Figure 1 is an exploded perspective view of an exemplary piezoelectric device 500 of the present disclosure. Figure 2 is a perspective view of the piezoelectric device 500 viewed from below. Figure 3 is a top view of the wiring board 100. Figure 4 is a bottom view of the wiring board 100. Figure 5 is a cross-sectional view taken along the line V-V in Figure 3. Figure 6 is a cross-sectional view taken along the line VI-VI in Figure 3. In Figure 3, the cover 200 and the piezoelectric vibrating element 400 are shown by dashed lines. In Figures 5 and 6, the cover 200 and the piezoelectric vibrating element 400 are shown by dashed lines. Figure 8 is an enlarged view of region R in Figure 6.

[0015] As shown in Figure 1, the piezoelectric device 500 comprises a package 300 and a piezoelectric vibrating element 400. The package 300 comprises a wiring board 100 and a cover 200. In reality, the wiring board 100 and the piezoelectric vibrating element 400 are joined via a bonding material 410 (see Figure 5), but the bonding material is omitted in Figure 1. The electrodes of the piezoelectric vibrating element 400 are also omitted from the illustration.

[0016] As shown in Figures 1 to 8, the wiring board 100 comprises an insulating substrate 130 having a base portion 110 having a first surface 111 and a second surface 112 located opposite the first surface 111, and a frame portion 120 located on the outer edge of the first surface 111. The wiring board 100 further comprises, as wiring elements, a connecting electrode 150 located on the first surface 111, a via conductor 171, an external electrode 172, a frame-shaped metallized layer 173, and a wiring conductor 170 connecting the frame-shaped metallized layer 173 and the external electrode 172.

[0017] The planar dimensions of the package 300 according to this disclosure may be, for example, 1.2 mm or less on the long side and 1.0 mm or less on the short side, 1.0 mm or less on the long side and 0.8 mm or less on the short side, or 0.8 mm or less on the long side and 0.6 mm or less on the short side. The thickness of the package 300 according to this disclosure may be, for example, 0.25 mm or less, 0.2 mm or less, 0.15 mm or less, or 0.1 mm or less. The height of the base 110 according to this disclosure may be, for example, 0.14 mm or less, 0.1 mm or less, 0.075 mm or less, or 0.05 mm or less. The height of the frame 120 according to this disclosure may be, for example, 0.16 mm or less, 0.1 mm or less, 0.75 mm or less, or 0.05 mm or less.

[0018] If the thickness of the package 300 is 0.2 mm, the heights of the base 110, frame 120, and lid 200 may be, for example, about 0.08 mm, 0.07 mm, and 0.05 mm, respectively. If the thickness of the package 300 is 0.15 mm, the heights of the base 110, frame 120, and lid 200 may be, for example, about 0.05 mm, 0.06 mm, and 0.04 mm, respectively. If the thickness of the package 300 is 0.1 mm, the heights of the base 110, frame 120, and lid 200 may be, for example, about 0.03 mm, 0.04 mm, and 0.03 mm, respectively. In any case, the thickness of the frame-shaped metallized layer 173, described later, may be about 0.015 mm.

[0019] The mounting area 180 of the wiring board 100 may be the area on the wiring board 100 that overlaps with the piezoelectric vibration element 400 when viewed from above. Alternatively, the mounting area 180 may be the area enclosed by imaginary lines connecting alignment marks (not shown) used when positioning the piezoelectric vibration element 400. The mounting area 180 can be defined according to the size of the piezoelectric vibration element 400 to be mounted. In Figure 3, for illustrative purposes, the first via conductor 171A, the second via conductor 171B, the wiring conductor 170, the external electrode 172, the connecting wiring 176, and the internal wiring 177 are shown as dashed lines when viewed from above.

[0020] The base portion 110 may be a flat plate-shaped insulator having a first surface 111 including a mounting area 180 on which the element is mounted, and a second surface 112 located opposite the first surface 111. The base portion 110 may, for example, have a rectangular shape in plan view.

[0021] The frame portion 120 is positioned on the first surface 111, surrounding the mounting area 180. The frame portion 120 may also be located on the outer edge of the first surface 111. By including the frame portion 120 in the wiring board 100, elements and the like can be protected even without the cover 200. The frame portion 120 may be integrated with the base portion 110. In a plan view, the outer edge of the frame portion 120 may overlap with the outer edge of the base portion 110.

[0022] The base portion 110 and the frame portion 120 may be made of an insulating inorganic material. The insulating inorganic material includes, for example, ceramic materials such as aluminum oxide sintered bodies (alumina ceramics), aluminum nitride sintered bodies, mullite sintered bodies, or glass ceramic sintered bodies. The base portion 110 and the frame portion 120 may be integrally formed, or they may be made of multiple laminated insulating layers or a single insulating layer.

[0023] The connecting electrode 150 is an electrode that is electrically connected to the terminal of the piezoelectric vibration element 400. As shown in Figure 5, the upper surface of the connecting electrode 150 may be flush with the first surface 111. Alternatively, the connecting electrode 150 may be located at the bottom of a recess (not shown) formed in the base portion 110, and the upper surface of the connecting electrode 150 may be flush with the bottom surface of the recess.

[0024] As shown in Figure 5, the piezoelectric vibration element 400 and the connecting electrode 150 may be joined via a bonding material 410. By positioning the connecting electrode 150 at the bottom of a recess formed in the base portion 110, and by joining the bonding material to the inner surface of the recess, the bonding strength between the bonding material 410 and the wiring board 100 is improved, and a thinner design becomes possible.

[0025] The connecting electrode 150 may include a conductor layer as a wiring conductor and a plating layer applied to the wiring layer. The plating layer may be a layer containing nickel and / or gold. For example, nickel plating may be applied to the exposed surface of the conductor layer, and gold plating may be applied on this nickel plating layer. This reduces the possibility of oxidative corrosion of the surface of the connecting electrode 150 and maintains good electrical connectivity between the terminals of the piezoelectric vibration element 400 and the connecting electrode 150 via the bonding material 410. The conductor layer of the connecting electrode 150 may be embedded in the base 110, and at least a part of the plating layer may be convex from the first surface 111.

[0026] The external electrode 172 includes a first external electrode 172A and a second external electrode 172B. As shown in Figures 2 and 4, the first external electrode 172A and the second external electrode 172B are each located on the second surface 112 of the base 110. The first external electrode 172A is an electrode electrically connected to the connecting electrode 150. The number of connecting electrodes 150 and the number of first external electrodes 172A may be the same, and each connecting electrode 150 may be connected to another first external electrode 172A. The second external electrode 172B is an electrode electrically connected to the frame-shaped metallization layer 173 and the lid 200.

[0027] The first external electrode 172A and the second external electrode 172B may each be positioned at the corners of the second surface 112. For example, the first external electrode 172A and the second external electrode 172B may each be located diagonally opposite each other on the second surface 112 of the base 110. Specifically, the first external electrode 172A may be located at one diagonal of the rectangular second surface 112, and the second external electrode 172B may be located at the other diagonal. The first external electrode 172A and the second external electrode 172B may extend from the second surface 112 of the base 110 to the side surfaces (including the corners between the side surfaces).

[0028] Since both the first external electrode 172A and the second external electrode 172B are located on the second surface 112 of the base portion 110, the package 300 and the piezoelectric device 500 can be surface-mounted on a mounting substrate.

[0029] The frame-shaped metallized layer 173 is a conductive layer located on the upper surface 121 of the frame portion 120. The frame-shaped metallized layer 173 is joined to the lid 200 using a sealing material such as gold-tin alloy (AuSn) or silver solder. The frame-shaped metallized layer 173 is an example of a metallized layer according to this disclosure.

[0030] As shown in Figure 8, the exposed surfaces of the frame-shaped metallization layer 173 and the external electrode 172 may be covered with a plating layer C made of nickel and / or gold, similar to the connecting electrode 150. Covering the frame-shaped metallization layer 173 with the plating layer C makes it easy and strong to connect the frame-shaped metallization layer 173 to the metal conductor lid 200. Covering the external electrode 172 with the plating layer makes it easy and strong to connect it to the electrodes of the mounting substrate on which the piezoelectric device 500 is mounted.

[0031] The via conductor 171 is a conductor that extends in the thickness direction of the insulating substrate 130. If the insulating substrate 130 includes multiple insulating layers, the via conductor 171 may be a through-conductor that extends through at least one insulating layer. The via conductor 171 includes a first via conductor 171A and a second via conductor 171B. As shown in Figures 5 and 6, the first via conductor 171A penetrates the base portion 110 and is a wiring that electrically connects the connecting electrode 150 and the first external electrode 172A.

[0032] The wiring conductor 170 is a wiring that connects the frame-shaped metallized layer 173 and the second external electrode 172B. As shown in Figures 6 to 8, the wiring conductor 170 includes an internal frame conductor 174 located inside the frame portion 120, a relay conductor 175 located inside the base portion 110, and a second via conductor 171B. The wiring conductor 170 may be a conductor that is not exposed on the surface of the insulating substrate 130.

[0033] The frame-type conductor 174 may be wiring that connects the frame-shaped metallized layer 173 and the intermediate conductor 175.

[0034] The intermediate conductor 175 may be a wiring that connects the frame conductor 174 and the second via conductor 171B. The intermediate conductor 175 is smoothly and continuously connected to the frame conductor 174 and extends in a direction generally parallel to the first surface 111. The broad surface of the intermediate conductor 175 does not need to be strictly parallel to the first surface 111, and may be slightly inclined or wavy. The frame conductor 174 and the intermediate conductor 175 are each plate-shaped, and their broad surfaces may have a curved shape. That is, the frame conductor 174 and the intermediate conductor 175 as a whole may have a curved shape in which the direction changes continuously. The broad surfaces of the frame conductor 174 and the intermediate conductor 175 may be oriented to follow the inner surface of the frame portion 120 and the first surface 111, respectively. The term "plate-shaped" here is not limited to flat plates, but includes those that are curved and have a curved shape (such as strips).

[0035] The second via conductor 171B extends in the thickness direction of the base portion 110 and may be a wiring that connects the relay conductor 175 and the second external electrode 172B. The frame-shaped metallized layer 173 is connected to the second external electrode 172B via the wiring conductor 170.

[0036] As shown in Figure 8, the frame conductor 174 has a first portion 174A that extends inward from the outer edge of the frame portion 120 adjacent to the frame-shaped metallized layer 173, and a second portion 174B that connects the first portion 174A and the intermediate conductor 175. In the first portion 174A, the end face on the outer edge side of the frame portion 120 may be covered with the plating layer C together with the end face of the frame-shaped metallized layer 173.

[0037] The first portion 174A of the frame-in-frame conductor 174 is connected to the back side (the contact surface side with the frame portion 120) of the frame-shaped metallized layer 173.

[0038] The cross-sections shown in Figures 6 and 8 are cross-sections obtained when the wiring board 100 is cut by a plane perpendicular to the first surface 111 and parallel to the extension direction of the first portion 174A. In these cross-sections, the length L1 of the first portion 174A in the extension direction (Y direction) may be 80% or more and 100% or less of the length L2 of the frame-shaped metallized layer 173 in the extension direction. The length L1 may be the length of the region in the above cross-section where the frame-shaped metallized layer 173 and the frame-internal conductor 174 are in contact.

[0039] In the packaging manufacturing process, the insulating substrate 130, including the frame portion 120, and the conductors, such as the frame-internal conductor 174, have different firing shrinkage rates. For example, the insulating substrate 130 may have a greater shrinkage rate than the conductor material. If the frame-internal conductor 174 does not have a first portion 174A and is connected to the frame-shaped metallized layer 173 substantially perpendicularly, the difference in shrinkage rates between the frame portion 120 and the frame-internal conductor 174 may cause the frame-internal conductor 174 to protrude from the upper surface 121 of the frame portion 120 during firing. This may cause the frame-shaped metallized layer 173 to be pushed up, potentially worsening the flatness of the upper part of the frame portion 120.

[0040] The frame-internal conductor 174 has a first portion 174A that extends adjacent to the frame-shaped metallized layer 173, thereby improving the flatness of the upper part of the frame portion 120. As a result, a wiring board 100 with excellent flatness at the portion to which the lid is joined can be realized, enabling more airtight hermetic sealing and improving the long-term reliability of the electronic device.

[0041] Furthermore, because the length L1 is between 80% and 100% of the length L2, the frame-internal conductor 174 is adjacent to the frame-shaped metallized layer 173 over a wide area of ​​the upper part of the frame 120. This reduces the deterioration of flatness even if an uplift event occurs.

[0042] The piezoelectric vibration element 400 may be a quartz crystal vibration element such as an AT-cut quartz crystal vibration element, an SC-cut quartz crystal vibration element, or a BT-cut quartz crystal vibration element. The piezoelectric vibration element 400 is an example of an electronic component according to this disclosure.

[0043] The lid 200 is made of, for example, a conductive metal and is joined to the frame-shaped metallized layer 173 to hermetically seal the package 300. The lid 200 may be made of, for example, an iron-nickel alloy or an iron-nickel-cobalt alloy. The lid 200 can be formed into a predetermined shape by adopting a conventionally well-known metal processing method such as a rolling method or a punching method. The lid 200 may be grounded. More specifically, by grounding the second external electrode 172B, the lid 200 can obtain a ground potential. By grounding the lid 200, the propagation of external noise into the package 300 can be reduced.

[0044] (Method for manufacturing a wiring board) An exemplary manufacturing method of the wiring board 100 will be described below.

[0045] First, through holes are provided in the ceramic green sheets to be the base 110 and the frame portion 120, conductors are injected, and the first via conductor 171A and the second via conductor 171B are formed. Using a mask, a metallized paste to be the in-frame conductor 174, the relay conductor 175, the connection electrode 150, and the internal wiring 177 is printed and applied (for example, screen printing) in an appropriate position range including above the second via conductor 171B on the ceramic green sheet. The internal wiring 177 is printed by connecting to one of the connection electrodes 150. Also, using a mask, a coating paste which is a ceramic paste of the same material as the ceramic green sheet is printed and applied (for example, screen printing) in an appropriate position range covering a part of the metallized paste.

[0046] On the lower surface side of the ceramic green sheet, the metallized paste is applied to each position of the external electrode 172 using a mask. Also, on the lower surface side of the ceramic green sheet, the metallized paste is further applied to the position of the connection wiring 176 including the wiring connecting the external electrodes 172 (the second external electrodes 172B) to each other. Further, a ceramic paste covering the connection wiring 176 connecting the external electrodes 172 to each other is applied to the lower surface side of the ceramic green sheet. The application of the metallized paste and the application of the ceramic paste are performed, for example, by screen printing.

[0047] A ceramic green sheet coated with a metallized paste on both sides is placed on a flat plate and pressed from the upper surface side by a pressing jig having irregularities in a shape corresponding to the frame portion 120.

[0048] Among the metallized paste, the in-frame conductor 174 is sandwiched between the coating paste and the ceramic green sheet and embedded. The upper end of the second via conductor 171B is pushed downward by the metallized paste and the coating paste that become the in-frame conductor 174.

[0049] On the lower surface side of the ceramic green sheet, the metallized paste and the ceramic paste become a planar shape, and the external electrode 172 connected via the connection wiring 176 is formed. Subsequently, a frame-shaped metallized layer 134 is formed by applying a metallized paste to the upper end of the formed frame portion 120. Subsequently, by performing a firing process at a temperature of 1300 to 1600°C, the wiring board 100 is obtained. Thereafter, if necessary, a plating process, attachment of the piezoelectric vibration element 400, bonding of the lid body 200, etc. are performed to obtain the piezoelectric device 500.

[0050] Alternatively, the wiring board 100 may be manufactured by laminating a plurality of ceramic green sheets having through holes at appropriate positions, injecting a conductor, applying a metallized paste, and then firing at a temperature of 1300 to 1600°C.

[0051] (Another aspect 1 of Embodiment 1) FIG. 9 is a top view of a wiring board 100A which is another aspect of the wiring board 100. In FIG. 9, the wiring located inside the wiring board 100A and the outer shape of the external electrode 172 are shown by broken lines.

[0052] As shown in Figure 9, the connecting electrode 150 may be located at opposing corners along the diagonal of the first surface 111. The first external electrode 172A and the second external electrode 172B may each be located at corners along the diagonal of the second surface 112. In a planar perspective view, the connecting electrode 150 is positioned overlapping with the first external electrode 172A. The two second external electrodes 172B are connected by connecting wiring 176 located inside the wiring board 100A. This configuration can be applied to a piezoelectric vibrator having connecting terminals along the diagonal.

[0053] This configuration allows the internal wiring 177 connecting the connecting electrode 150 and the first external electrode 172A, and the connecting wiring 176, to be arranged without overlapping in a planar perspective view. This makes it possible to reduce the height of the wiring board 100A while ensuring insulation between the internal wiring 177 (signal wiring) for connecting the connecting electrode 150 and the first external electrode 172A and the grounding wiring.

[0054] (Another embodiment 2 of Embodiment 1) Figure 10 is a partial cross-sectional view of the wiring board 100 showing another embodiment of the frame conductor 174. As shown in the example in Figure 10, the first portion 174A of the frame conductor 174 may extend from the outer edge to the inner edge of the frame portion 120. Since the frame conductor 174 is adjacent to the frame-shaped metallized layer 173 from the outer edge to the inner edge of the frame portion 120, the deterioration of flatness can be further reduced even if a push-up event occurs.

[0055] Furthermore, if the first portion 174A extends from the outer edge to the inner edge of the frame portion 120, the second portion 174B may have a connecting portion 174BX that extends away from the inner surface of the frame portion 120, starting from the connection portion with the first portion 174A. Having the connecting portion 174BX in the second portion 174B reduces the possibility of the second portion 174B being exposed from the inner surface of the frame portion 120, even if the first portion 174A extends to the inner edge of the frame portion 120.

[0056] Alternatively, as shown in Figure 8, the second portion 174B of the frame-in-frame conductor 174, where the length L1 of the first portion 174A is 80% to 100% of the length L2 of the frame-shaped metallized layer 173 in the extension direction, may have a separation portion 174BX. With this configuration, even if the first portion 174A extends close to the inner edge of the frame portion 120, the possibility of the second portion 174B being exposed from the inner surface of the frame portion 120 can be reduced.

[0057] (Another embodiment 3 of Embodiment 1) Figure 11 is a partial cross-sectional view of the wiring board 100 showing another embodiment of the frame-in-frame conductor 174. Figure 11 shows a cross-section when cut by a plane perpendicular to the first surface 111 and parallel to the extension direction of the first portion 174A. As shown in the example in Figure 11, in this cross-section, the length L1 of the first portion 174A in the extension direction of the first portion 174A may be 50% or more and 80% or less of the length L2 of the frame-shaped metallized layer 173 in the extension direction.

[0058] By having a length L1 that is between 50% and 80% of the length L2, the flatness of the upper surface of the frame portion 120 is improved, and the possibility of the internal frame conductor 174 being exposed from the inner surface of the frame portion 120 is reduced. Furthermore, because the second portion 174B is inclined outward, the thickness between the internal frame conductor (second portion 174B) and the inner surface of the frame portion 120 becomes thicker closer to the upper surface 121. As a result, even if thermal stress is applied when the lid 200 is joined to the frame-shaped metallized layer 173 of the upper surface 121, the possibility of cracks occurring on the inside of the frame portion 120 or the insulator (part of the frame portion 120) peeling off from the upper surface 121 side (exposure of the internal frame conductor) is reduced.

[0059] (Another embodiment 4 of Embodiment 1) Figure 12 is a partial cross-sectional view of the wiring board 100 showing another embodiment of the frame conductor 174. As shown in the example in Figure 12, the second portion 174B of the frame conductor 174 is a portion continuous with the first portion 174A and may have an inclined portion 174BY whose inclination angle θ from the upper surface of the frame portion 120 is 1° or more and 30° or less.

[0060] A portion of the second part 174B has an inclined portion 174BY with a small inclination angle θ with respect to the upper surface of the frame portion 120. This causes the insulator, which is part of the frame portion 120, to wedge-shaped into the space between the upper surface of the inclined portion 174BY and the upper surface 121 of the frame portion 120. This reduces the possibility of the insulator located inside the frame conductor 174 peeling off.

[0061] (Another embodiment 5 of Embodiment 1) Figure 13 is a partial cross-sectional view of the wiring board 100 showing another embodiment of the frame portion 120 and the frame-internal conductor 174. As shown in the example in Figure 13, the inner surface of the frame portion 120 may be inclined outward, and the second portion 174B of the frame-internal conductor 174 may be inclined along the inner surface. With this configuration, the thickness between the second portion 174B and the inner surface of the frame portion 120 becomes substantially uniform, and the angle between the inner surface and the first surface 111 becomes obtuse. This reduces the possibility of cracks occurring in the insulator located on the inner surface side of the second portion 174B. The frame portion 120 may also have a tapered shape, with the inner surface inclined outward and the outer surface inclined inward.

[0062] Furthermore, the corner between the inner surface and the first surface 111 may have a rounded edge, as shown in Figure 13. Having a rounded edge at the corner reduces the possibility of cracks occurring at that corner.

[0063] [Other Embodiments] The embodiments described above are illustrative and can be modified in various ways.

[0064] For example, one or both of the inner surface of the frame portion 120 and the first surface 111 of the base portion 110 may include a curved surface rather than being a flat surface.

[0065] Furthermore, the number, arrangement, and positional relationship of the connecting electrodes 150, external electrodes 172, and the wiring connecting them may be appropriately changed depending on the electronic components mounted on the wiring board 100. For example, the first external electrode 172A and the second external electrode may each be located at the corners along the short side direction (Y direction) of the wiring board 100. In this case, the connecting electrode 150 located along the short side direction (Y direction) of the wiring board 100 as shown in Figure 1 may be connected to the external electrode 172 directly below it only by via conductors. The connecting electrode 150 may also be located on the diagonal of the wiring board 100. In addition, the shape of the connecting electrode 150 may be changed.

[0066] (Summary) (1) The wiring board according to Embodiment 1 of the present disclosure comprises a base having a first surface and a second surface located opposite to the first surface, a frame located on the outer edge of the first surface, a metallized layer located on the upper surface of the frame, an internal frame conductor located inside the frame, and a relay conductor located inside the base, wherein the internal frame conductor has a first portion extending inward from the outer edge of the frame adjacent to the metallized layer, and a second portion connecting the first portion and the relay conductor.

[0067] (2) In the wiring board according to embodiment 2 of the present disclosure, in the cross section when cut by a plane perpendicular to the first surface and parallel to the stretching direction of the first portion, the length of the first portion in the stretching direction is 80% or more and 100% or less of the length of the metallized layer in the stretching direction.

[0068] (3) In the wiring board according to embodiment 3 of the present disclosure, in embodiment 1, the first portion extends from the outer edge to the inner edge of the frame portion.

[0069] (4) In the wiring board according to embodiment 4 of the present disclosure, in embodiment 2 or 3, the second portion has a connecting portion that starts from the connection portion with the first portion and extends away from the inner surface of the frame portion.

[0070] (5) In the wiring board according to embodiment 5 of the present disclosure, in embodiment 1, when the board is cut by a plane perpendicular to the first surface and parallel to the stretching direction of the first portion, the length of the first portion in the stretching direction is 50% or more and 80% or less of the length of the metallized layer in the stretching direction.

[0071] (6) In the wiring board according to embodiment 6 of the present disclosure, in embodiment 1, 2, or 5, the second portion is a portion continuous with the first portion and has an inclined portion having an inclination angle of 1° or more and 30° or less from the upper surface of the frame portion.

[0072] (7) The package according to embodiment 7 of the present disclosure comprises a wiring board according to any of embodiments 1 to 6 above and a cover.

[0073] (8) An electronic device relating to aspect 8 of the present disclosure comprises the package described in aspect 7 and an electronic component.

[0074] [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.

[0075] 100, 100A... Wiring board 110... Base 120... Frame 121... Top surface 130... Insulating substrate 150... Connecting electrode 170... Wiring conductor 171... Via conductor 172... External electrode 172A... First external electrode 172B... Second external electrode 173... Frame-shaped metallized layer 174... Internal conductor 174A... First part 174B... Second part 174BX... Separation part 174BY... Inclined part 175... Intermediate conductor 176... Connecting wiring 177... Internal wiring 200... Cover 300... Package 400... Piezoelectric vibration element 500... Piezoelectric device

Claims

1. A wiring board comprising: a base having a first surface and a second surface located opposite the first surface; a frame located on the outer edge of the first surface; a metallized layer located on the upper surface of the frame; an internal frame conductor located inside the frame; and a relay conductor located inside the base, wherein the internal frame conductor has a first portion extending inward from the outer edge of the frame adjacent to the metallized layer, and a second portion connecting the first portion and the relay conductor.

2. The wiring board according to claim 1, wherein, in a cross-section obtained by cutting with a plane perpendicular to the first surface and parallel to the stretching direction of the first portion, the length of the first portion in the stretching direction is 80% or more and 100% or less of the length of the metallized layer in the stretching direction.

3. The wiring board according to claim 1, wherein the first portion extends from the outer edge to the inner edge of the frame portion.

4. The wiring board according to claim 2 or 3, wherein the second portion has a connecting portion that starts from the connection portion with the first portion and extends in a direction away from the inner surface of the frame portion.

5. The wiring board according to claim 1, wherein, in a cross-section obtained by cutting with a plane perpendicular to the first surface and parallel to the stretching direction of the first portion, the length of the first portion in the stretching direction is 50% or more and 80% or less of the length of the metallized layer in the stretching direction.

6. The wiring board according to claim 1, 2, or 5, wherein the second portion is a portion continuous with the first portion and has an inclined portion whose angle of inclination from the upper surface of the frame portion is 1° or more and 30° or less.

7. A package comprising a wiring board according to any one of claims 1 to 6 and a cover.

8. An electronic device comprising the package described in claim 7 and an electronic component.

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