Wiring board, package, and electronic device

Abstract

The present invention reduces deterioration in flatness of a portion to which a lid body is joined. This wiring board is provided with: an insulating substrate that includes a base part and a frame part; a metallized layer that is positioned on the upper surface of the frame part; an external electrode; and a wiring conductor that connects the metallized layer and the external electrode to each other. The wiring conductor includes an in-frame conductor that is positioned inside the frame part. The in-frame conductor and the metallized layer are connected to each other in an outer region that is a region on the outer edge side of the metallized layer.

Description

Wiring boards, packages and electronic devices

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

[0002] Patent Document 1 discloses an electronic component storage package. The package includes a lid and a wiring board. The wiring board includes an insulating substrate, an electrical wiring structure, and the like, and has a plate-shaped first conductor portion inside a frame portion of the insulating substrate.

[0003] In recent years, there has been a demand for thinner packages for housing such electronic components.

[0004] WO2019 / 131866 publication

[0005] A wiring board according to one embodiment of the present disclosure comprises an insulating base including a base having a first surface and a second surface opposite the first surface, and a frame portion located on the outer edge of the first surface, a metallization layer located on the upper surface of the frame portion, an external electrode located on the second surface, and a wiring conductor connecting the metallization layer and the external electrode, wherein the wiring conductor includes an inner-frame conductor located inside the frame portion, and the inner-frame conductor and the metallization layer are connected in an outer region which is the region on the outer edge side of the metallization layer.

[0006] A package according to one aspect of the present disclosure includes the wiring substrate and a lid.

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

[0008] 17 is an exploded perspective view of a piezoelectric device according to embodiment 1 of the present disclosure. 18 is a perspective view of the piezoelectric device as seen from below. 19 is a top view of a wiring board according to embodiment 1 of the present disclosure. 20 is a bottom view of a wiring board according to embodiment 1 of the present disclosure. 21 is a cross-sectional view taken along line V-V in FIG. 3. 22 is a cross-sectional view taken along line VI-VI in FIG. 3. 23 is an enlarged view of a portion corresponding to region R in FIG. 6. 24 is a partial cross-sectional view of a wiring board showing another embodiment of a frame-shaped metallization layer. 25 is a top view of a wiring board according to embodiment 2. 26 is a bottom view of a wiring board according to embodiment 2. 27 is a cross-sectional view taken along line XI-XI in FIG. 25. 28 is a cross-sectional view taken along line XII-XII in FIG. 26. 29 is a cross-sectional view taken along line XIII-XIII in FIG. 27. 29 is a partial cross-sectional view of a piezoelectric device according to embodiment 2, and an enlarged view of a portion corresponding to region R in FIG. 3. 30 is a top view of a wiring board according to embodiment 3. 31 is a cross-sectional view taken along line VXI-VXI in FIG. 35. 32 is a cross-sectional view taken along line VXII-VXII in FIG. 36. 33 is an enlarged view of a portion corresponding to region R in FIG. 37. 34 is a partial cross-sectional view of a wiring board showing a modified example of a frame portion and an intra-frame conductor.

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

[0010] During the package manufacturing process, there is a difference in the firing shrinkage rate between the insulating substrate including the frame portion and the wiring conductor within the frame portion, which may affect the flatness of the top surface of the frame portion, especially when thinning the wiring having a conductor within the frame portion.

[0011] According to one aspect of the present disclosure, a wiring board with excellent flatness at the portion to which the lid is bonded can be realized.

[0012] [Embodiment 1] A wiring board, a package, and a piezoelectric device according to a 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 top and bottom in the following description is for convenience and does not limit the top and bottom when the wiring board, package, and piezoelectric device are actually used. In this specification, the surface of the wiring board on which the piezoelectric vibration element is mounted is defined as the top surface. In the drawings, the positive direction of the Z axis is the upward direction. The X axis is the longitudinal axis direction of the wiring board, and the Y axis is an axis that intersects perpendicularly with the X axis and the Z axis. The Z axis is also defined as the thickness direction of the wiring board.

[0014] FIG. 1 is an exploded perspective view of an exemplary piezoelectric device 500 according to the present disclosure. FIG. 2 is a perspective view of the piezoelectric device 500 as viewed from below. FIG. 3 is a top view of the wiring substrate 100. FIG. 4 is a bottom view of the wiring substrate 100. FIG. 5 is a cross-sectional view taken along line V-V in FIG. 3. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 3. In FIG. 3, the lid 200 and the piezoelectric vibration element 400 are illustrated by imaginary lines indicated by two-dot chain lines. In FIGS. 5 and 6, the lid 200, the piezoelectric vibration element 400, and the bonding material 410 are illustrated by imaginary lines indicated by two-dot chain lines. FIG. 7 is an enlarged view of a portion corresponding to region R in FIG. 6.

[0015] As shown in Fig. 1, the piezoelectric device 500 includes a package 300 and a piezoelectric vibration element 400. The package 300 includes a wiring substrate 100 and a lid 200. In reality, the wiring substrate 100 and the piezoelectric vibration element 400 are bonded via a bonding material 410 (see Fig. 5), but the bonding material is omitted in Fig. 1. The electrodes of the piezoelectric vibration element 400 are also omitted from the illustration.

[0016] 1 to 7 , wiring board 100 includes insulating base 130 having base 110 with first surface 111 and second surface 112 located opposite first surface 111, and frame 120 located on the outer edge of first surface 111. Wiring board 100 further includes, as wiring elements, connection electrode 150 located on first surface 111, via conductor 171, external electrode 172, frame-shaped metallization layer 173, and wiring conductor 170 connecting frame-shaped metallization layer 173 and external electrode 172.

[0017] The planar size of the package 300 according to the present disclosure may be, for example, a long side of 1.2 mm or less and a short side of 1.0 mm or less, a long side of 1.0 mm or less and a short side of 0.8 mm or less, or a long side of 0.8 mm or less and a short side of 0.6 mm or less. The thickness of the package 300 according to the present 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 the present 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 the present 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] When 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, approximately 0.08 mm, 0.07 mm, and 0.05 mm, respectively. When 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, approximately 0.05 mm, 0.06 mm, and 0.04 mm, respectively. When 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, approximately 0.03 mm, 0.04 mm, and 0.03 mm, respectively. In either case, the thickness of the frame-shaped metallized layer 173 (described later) may be, for example, approximately 0.015 mm.

[0019] The two-dot chain lines in FIG. 3 represent the virtual outer edges of the lid 200 and the piezoelectric vibration element 400 when the lid 200 and the piezoelectric vibration element 400 are disposed on the wiring substrate 100. The mounting area 180 of the wiring substrate 100 may be a region of the wiring substrate 100 that overlaps with the piezoelectric vibration element 400 when viewed from above. That is, it may be the region indicated by the two-dot chain line located inside the frame portion 120 in FIG. 3. Alternatively, the mounting area 180 may be a region surrounded by virtual lines connecting alignment marks (not shown) used when disposing the piezoelectric vibration element 400. The mounting area 180 may be defined according to the size of the piezoelectric vibration element 400 to be mounted. For ease of explanation, FIG. 3 shows the first via conductor 171A, the second via conductor 171B, and the wiring conductor 170 as viewed from above with dashed lines.

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

[0021] The frame portion 120 is located on the first surface 111, surrounding the mounting region 180. The frame portion 120 may be located on the outer edge of the first surface 111. By providing the frame portion 120 on the wiring substrate 100, elements and the like can be protected when the lid body 200 is not provided. The frame portion 120 may be integral with the base portion 110. In a plan view, the outer edge of the frame portion 120 may overlap the outer edge of the base portion 110.

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

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

[0024] 5, the piezoelectric vibration element 400 and the connection electrode 150 may be bonded via a bonding material 410. By positioning the connection electrode 150 on the bottom surface of a recess formed in the base 110, the bonding strength between the connection electrode 150 and the wiring substrate 100 by the bonding material 410 is improved, and a thinner structure is possible.

[0025] The connection electrode 150 may include a conductor layer as a wiring conductor and a plating layer deposited on 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 to the nickel plating layer. This reduces the possibility of oxidation corrosion on the surface of the connection electrode 150 and maintains good electrical connectivity between the terminal of the piezoelectric vibration element 400 and the connection electrode 150 via the bonding material 410. The conductor layer of the connection electrode 150 may be embedded in the base 110, and at least a portion of the plating layer may be protruding from the first surface 111.

[0026] The external electrodes 172 include 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 connection electrode 150. The number of connection electrodes 150 and the number of first external electrodes 172A may be the same, and each connection electrode 150 may be connected to a different first external electrode 172A. The second external electrode 172B is an electrode electrically connected to the lid 200.

[0027] The first external electrode 172A and the second external electrode 172B may each be disposed at a corner of the second surface 112. For example, the first external electrode 172A and the second external electrode 172B may each be located at a corner along the short side direction (Y direction) of the wiring substrate 100. 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 surface (including the corner between the side surfaces).

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

[0029] The frame-shaped metallization layer 173 is a conductive layer located on the upper surface 121 of the frame portion 120. The frame-shaped metallization layer 173 is joined to the lid body 200 using a sealing material S (see FIG. 9 ) such as a gold-tin alloy (AuSn) or silver solder. The frame-shaped metallization layer 173 is an example of a metallization layer according to the present disclosure.

[0030] 7 and 8 , the exposed surfaces of the frame-shaped metallization layer 173 and the external electrode 172 may be covered with a plating layer C of nickel and / or gold, similar to the connection electrode 150. Covering the frame-shaped metallization layer 173 with the plating layer C facilitates and strengthens the connection between the frame-shaped metallization layer 173 and the lid 200, which is a metal conductor. Covering the external electrode 172 with a plating layer facilitates and strengthens the connection with an electrode of a mounting substrate on which the piezoelectric device 500 is mounted.

[0031] The via conductors 171 are conductors that extend in the thickness direction of the insulating base 130. When the insulating base 130 includes multiple insulating layers, the via conductors 171 may be through conductors that extend through at least one of the insulating layers. The via conductors 171 include a first via conductor 171A and a second via conductor 171B. As shown in Figures 5 and 6, the first via conductor 171A is a wiring that penetrates the base 110 and connects the connection 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 and 7, the wiring conductor 170 includes an intra-frame conductor 174 located inside the frame 120, a relay conductor 175 located inside the base 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 base 130.

[0033] The inner-frame conductor 174 may be a wiring that connects the frame-shaped metallization layer 173 and the relay conductor 175. The inner-frame conductor 174 penetrates the interior of the frame 120 generally in the Z direction without being exposed on the inner or outer surface of the frame 120. The inner-frame conductor 174 is connected to the back side of the frame-shaped metallization layer 173 (the side that comes into contact with the frame 120).

[0034] The relay conductor 175 may be a wiring that connects the in-frame conductor 174 and the second via conductor 171B. The relay conductor 175 is connected to the in-frame conductor 174 in a smooth, continuous manner and extends in a direction generally parallel to the first surface 111. The broad surface of the relay conductor 175 does not need to be strictly parallel to the first surface 111; it may be slightly inclined or wavy. The in-frame conductor 174 and the relay conductor 175 may each be plate-shaped, and their broad surfaces may have a curved shape. That is, the in-frame conductor 174 and the relay conductor 175 may have a curved shape whose direction changes continuously as a whole. The broad surfaces of the in-frame conductor 174 and the relay conductor 175 may be oriented along the inner surface of the frame portion 120 and the first surface 111, respectively. The term "plate-shaped" used here is not limited to a flat plate shape and includes curved shapes (such as a strip shape).

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

[0036] 7, the inner-frame conductor 174 is connected to the frame-shaped metallization layer 173 in an outer region 173X, which is a region on the outer edge side of the frame-shaped metallization layer 173. The outer region 173X may be, for example, a region ranging from the outer edge of the frame-shaped metallization layer 173 to a distance that is one-third of the width of the frame-shaped metallization layer 173.

[0037] In the package manufacturing process, the insulating base 130 including the frame 120 has a different firing shrinkage rate from the conductors such as the frame conductor 174. For example, if the insulating base 130 has a larger shrinkage rate than the conductive material, the difference in shrinkage rate between the frame 120 and the frame conductor 174 may cause the frame conductor 174 to protrude from the upper surface 121 of the frame 120 during firing and push up against the frame-shaped metallized layer 173.

[0038] Even if the flatness of the upper surface 121 of the frame 120 deteriorates due to the difference in shrinkage rate, the inner-frame conductor 174 and the frame-shaped metallization layer 173 are connected in the outer region 173X, so the portion of the upper surface of the frame-shaped metallization layer 173 where the flatness deteriorates is the outer region 173X. Furthermore, as shown in FIG. 5 , the lid 200 is typically designed to be slightly smaller than the wiring substrate 100 in a planar view. This minimizes the impact on the flatness of the portion of the frame-shaped metallization layer 173 where the lid 200 is mounted, thereby reducing the deterioration of the flatness of the portion where the lid 200 is bonded. Furthermore, compared to when the inner-frame conductor 174 and the frame-shaped metallization layer 173 are connected in the inner region of the frame-shaped metallization layer 173, the flatness of the portion where the lid 200 is bonded can be improved. This allows for a wiring substrate 100 with excellent flatness in the portion where the lid is bonded, enabling more airtight sealing and improving the long-term reliability of electronic devices.

[0039] FIG. 8 is a partial cross-sectional view of the wiring substrate 100 showing another embodiment of the frame-shaped metallization layer 173. As shown in FIG. 8 , the cross-sectional thickness of the frame-shaped metallization layer 173 along its width direction may be thicker on the outside than on the inside. In other words, the cross-sectional thickness of the frame-shaped metallization layer 173 along its width direction is thicker in the outer region on the outer edge than in the inner region on the inner edge. Connecting the inner-frame conductor 174 to the outer region 173X of the frame-shaped metallization layer 173, which has a relatively large thickness, can reduce the impact of deterioration in flatness due to the firing shrinkage of the frame portion 120 and the inner-frame conductor 174. More specifically, even if the inner-frame conductor 174 were to protrude toward the upper surface of the frame portion 120 due to the difference in shrinkage between the insulating base 130 including the frame portion 120 and the inner-frame conductor 174, the thicker outer region of the frame-shaped metallization layer 173 can mitigate the impact of the inner-frame conductor 174 protruding.

[0040] The piezoelectric vibrating element 400 may be a quartz crystal vibrating element such as an AT-cut quartz crystal vibrating element, an SC-cut quartz crystal vibrating element, a BT-cut quartz crystal vibrating element, etc. The piezoelectric vibrating element 400 is an example of an electronic component according to the present disclosure.

[0041] The lid 200 is made of, for example, a conductive metal and is bonded to the frame-shaped metallization 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 employing a conventional 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, it is possible to reduce the propagation of external noise into the package 300.

[0042] (Method for Manufacturing Wiring Board) An exemplary method for manufacturing the wiring board 100 will now be described.

[0043] First, through holes are formed in the ceramic green sheets that will become base 110 and frame 120, and a conductor is injected to form first via conductors 171A and second via conductors 171B. A metallization paste that will become frame conductors 174 and relay conductors 175 is applied by printing (e.g., screen printing) using a mask to an appropriate positional range on the ceramic green sheets, including above second via conductors 171B. Furthermore, a coating paste that is a ceramic paste made of the same material as the ceramic green sheets is applied by printing (e.g., screen printing) using a mask to an appropriate positional range that covers part of the metallization paste.

[0044] A mask is used to apply metallization paste to the lower surface of the ceramic green sheet at each position of the external electrodes 172. Metallization paste is also applied to the lower surface of the ceramic green sheet at the positions of internal wiring (not shown), including wiring connecting the external electrodes 172 together. Furthermore, ceramic paste is applied to the lower surface of the ceramic green sheet to cover the internal wiring connecting the external electrodes 172 together. The application of the metallization paste and the ceramic paste is performed by, for example, screen printing.

[0045] The ceramic green sheet with the metallization paste applied on both sides is placed on a flat plate, and pressure is applied from above using a pressure jig having projections and depressions in a shape corresponding to the frame portion 120 .

[0046] The inner-frame conductor 174 of the metallization paste is sandwiched and embedded between the coating paste and the ceramic green sheet. The upper end of the second via conductor 171B is pressed downward by the metallization paste and coating paste that become the inner-frame conductor 174.

[0047] The metallization paste and ceramic paste are formed into a planar shape on the underside of the ceramic green sheet, forming external electrodes 172 connected via internal wiring. A firing process is then performed at a temperature of 1300 to 1600°C, thereby obtaining the wiring substrate 100. Thereafter, plating processes, attachment of the piezoelectric vibration element 400, and bonding of the lid 200 are performed as necessary, thereby obtaining the piezoelectric device 500.

[0048] Alternatively, the wiring substrate 100 may be fabricated by stacking multiple ceramic green sheets having through holes at appropriate positions, injecting a conductor, applying a metallization paste, and then firing the resulting sheets at a temperature of 1300 to 1600°C.

[0049] [Embodiment 2] A second embodiment of the present disclosure will be described below. For convenience of explanation, components having the same functions as those described in the above embodiment will be denoted by the same reference numerals, and their description will not be repeated. The same applies to the following embodiments.

[0050] FIG. 9 is a top view of a wiring board 100B according to the second embodiment. In FIGS. 9 to 13, hidden wiring and the like are shown with dashed lines for the sake of explanation. FIG. 10 is a bottom view of the wiring board 100B. FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. 9. FIG. 12 is a cross-sectional view taken along line XII-XII in FIG. 9. FIG. 13 is a cross-sectional view taken along line XIII-XIII in FIG. 9. In FIGS. 11 to 13, the lid 200, the piezoelectric vibration element 400, and the bonding material 410 are shown by imaginary lines indicated by two-dot chain lines.

[0051] 10 , the first external electrode 172A and the second external electrode 172B may be located at corners along different diagonal lines of the second surface 112. Specifically, the first external electrode 172A may be located at one pair of diagonal corners of the rectangular second surface 112, and the second external electrode 172B may be located at the other pair of diagonal corners.

[0052] As shown in FIG. 12, the connection electrode 150 and a first external electrode 172A located away from the connection electrode 150 may be connected via an internal wiring 177 located inside the base 110.

[0053] Fig. 14 is a partial cross-sectional view of a piezoelectric device 500B according to the second embodiment, and is an enlarged view of a portion corresponding to region R in Fig. 13. The piezoelectric device 500B includes a wiring substrate 100B.

[0054] 14, the inner-frame conductor 174 may be connected to the outer end of the frame-shaped metallization layer 173. By connecting the inner-frame conductor 174 to the outer end of the frame-shaped metallization layer 173, the flatness of the portion on which the lid body 200 is mounted is less likely to be affected, and the flatness of the portion to which the lid body is joined can be improved.

[0055] 14 , the in-frame conductor 174 of the wiring board 100B may have a first portion 174A and a second portion 174B. The first portion 174A is a portion that extends mainly inward (in the Y direction) of the frame portion 120 from the connection portion with the frame-shaped metallization layer 173. The first portion 174A may be smoothly connected to the second portion 174B. The length of the first portion 174A in the width direction of the frame portion 120 may be half or more of the width of the frame portion 120.

[0056] The second portion 174B is a portion that extends from the inner end of the first portion 174A mainly in the height direction (Z direction) of the frame portion 120 toward the inside of the base portion 110. The second portion 174B may be connected to the relay conductor 175 in a smooth, continuous manner.

[0057] By including the first portion 174A, even if a push-up occurs in the Z-axis direction due to differences in firing shrinkage rates caused by the intra-frame conductor 174, the push-up occurs over a wide surface. This improves the flatness of the portion where the lid 200 is bonded, compared to when the intra-frame conductor 174 and the frame-shaped metallization layer 173 are connected in the inner region of the frame-shaped metallization layer 173. Furthermore, because the length of the first portion 174A in the width direction of the frame 120 is at least half the width of the frame 120, the push-up occurs over a wider surface, reducing the push-up in the Z direction, and thus further improving the flatness of the portion where the lid 200 is bonded.

[0058] [Embodiment 3] Fig. 15 is a top view of a wiring substrate 100C according to embodiment 3. In Fig. 15, hidden wiring and the like are indicated by dashed lines. Fig. 16 is a cross-sectional view taken along line XVI-XVI in Fig. 15. Fig. 17 is a cross-sectional view taken along line XVII-XVII in Fig. 15. As shown in Fig. 15, connection electrodes 150 may be located on a diagonal line of the wiring substrate 100C.

[0059] 15 , the connection electrodes 150 may be located at diagonally opposing corners of the first surface 111. In a planar perspective, the connection electrodes 150 are located so as to overlap the first external electrode 172A. The diagonally arranged connection electrodes 150 may be connected to the external electrode 172 directly below them by via conductors only. The two second external electrodes 172B are connected by connection wiring 176 located inside the wiring substrate 100C. This configuration can be applied to a piezoelectric vibration element having connection terminals along a diagonal line.

[0060] With this configuration, connection electrode 150 and first external electrode 172A can be connected by first via conductor 171A without internal wiring 177. Therefore, there is no need to provide internal wiring 177 connecting connection electrode 150 and first external electrode 172A, and connection wiring 176 and internal wiring 177 do not overlap in a planar perspective view. This allows wiring substrate 100C to be made low-profile while ensuring insulation between the signal wiring from connection electrode 150 to first external electrode 172A and connection wiring 176 connected to second external electrode 172B at ground potential.

[0061] FIG. 18 is a partial cross-sectional view of a wiring board 100C according to the third embodiment. As shown in FIG. 18 , the outer end 174P of the inner-frame conductor 174 may be exposed on the outer surface of the frame 120. With this configuration, the inner-frame conductor 174 connects to the frame-shaped metallization layer 173 in a region closer to the outer edge of the frame-shaped metallization layer 173, which is less likely to affect the flatness of the portion on which the lid 200 is mounted, thereby improving the flatness of the portion to which the lid 200 is joined. Furthermore, because the outer end 174P is exposed on the outer surface of the frame 120, a continuous plating layer can be applied from the side surface of the frame-shaped metallization layer 173 to the outer end 174P. The plating layer applied to the outer end 174P acts as a conductive path at the connection between the inner-frame conductor 174 and the frame-shaped metallization layer 173, thereby improving the connection reliability with the frame-shaped metallization layer 173.

[0062] Furthermore, the wiring substrate 100C may be a substrate formed by cutting a mother substrate (multi-piece substrate) along a dividing groove. Specifically, the wiring substrate 100C may be manufactured, for example, by preparing a mother substrate and dividing the mother substrate into individual pieces. The mother substrate has multiple wiring substrate regions arranged vertically and horizontally on the substrate surface. The mother substrate has a dividing groove at the boundary between two adjacent wiring substrate regions, and the individual wiring substrates 100C are obtained by breaking the mother substrate along the dividing groove. The dividing groove may be formed by partially cutting the mother substrate before or after firing using a laser or a cutter blade.

[0063] In this case, the outer side surface of wiring substrate 100C corresponds to the groove in the mother substrate and has inclined surface 132, which is a cut surface made by a laser or the like, and fracture surface 131. Specifically, the center of side surface 105 in the thickness direction is fracture surface 131, and inclined surface 132 is located closer to first surface 102 and second surface 103 than fracture surface 131.

[0064] When the motherboard is divided into individual pieces, inclined surfaces 132 and fractured surfaces 131 are formed as shown in Fig. 18. The outer end 174P may be located on the inclined surfaces 132 on the outer side surfaces of the wiring board 100C.

[0065] FIG. 19 is a partial cross-sectional view of a wiring substrate 100C showing a modified example of the frame portion 120 and the intra-frame conductor 174. As shown in FIG. 19 , the inner surface of the frame portion 120 may be inclined outward, and the second portion 174B of the intra-frame conductor 174 may be inclined approximately parallel to the inner surface. This configuration results in a substantially uniform thickness between the second portion 174B and the inner surface of the frame portion 120, and an obtuse angle between the inner surface and the first surface 111. This reduces the likelihood of cracks occurring in the insulator located on the inner surface side of the second portion 174B. The frame portion 120 may be tapered, with the inner surface inclined outward and the outer surface inclined inward, forming an inclined surface 132.

[0066] Furthermore, the corner between the inner surface and the first surface 111 may have a rounded surface as shown in Fig. 19. By having the corner have a rounded surface, the possibility of cracks occurring at the corner can be further reduced.

[0067] Other Embodiments The above-described embodiments are merely examples, and various modifications are possible.

[0068] For example, one or both of the inner surface of frame 120 and first surface 111 of base 110 may not be flat but may include a curved surface. Also, frame 120 may have a shape with a step midway.

[0069] Furthermore, the number, arrangement, and positional relationship of the connection electrodes 150, the external electrodes 172, and the wiring connecting them may be changed as appropriate depending on the electronic components mounted on the wiring substrate 100. Furthermore, the shape of the connection electrodes 150 may be changed.

[0070] [Summary] (1) A wiring board according to aspect 1 of the present disclosure comprises an insulating base including a base having a first surface and a second surface opposite the first surface, and a frame portion located on the outer edge of the first surface, a metallization layer located on the upper surface of the frame portion, an external electrode located on the second surface, and a wiring conductor connecting the metallization layer and the external electrode, wherein the wiring conductor includes an inner-frame conductor located inside the frame portion, and the inner-frame conductor and the metallization layer are connected in an outer region which is the region on the outer edge side of the metallization layer.

[0071] (2) In a wiring board according to aspect 2 of the present disclosure, in the above-mentioned aspect 1, the outer region is a region ranging from the outer edge of the metallization layer to a distance of one-third of the width of the metallization layer.

[0072] (3) A wiring board according to a third aspect of the present disclosure is the wiring board of the first or second aspect, wherein the in-frame conductor has a first portion that extends mainly inward from the connection portion with the metallized layer toward the inside of the frame portion.

[0073] (4) A wiring board according to a fourth aspect of the present disclosure is the wiring board of the third aspect, wherein the length of the first portion in the width direction of the frame is equal to or greater than half the width of the frame.

[0074] (5) A wiring board according to aspect 5 of the present disclosure is the wiring board of any one of aspects 1 to 4, wherein the in-frame conductor is connected to an outer end of the metallized layer.

[0075] (6) A wiring board according to a sixth aspect of the present disclosure is the wiring board of any one of the first to fifth aspects, wherein an outer end of the in-frame conductor is exposed on an outer surface of the frame portion.

[0076] (7) A package according to a seventh aspect of the present disclosure includes the wiring substrate of any one of the first to sixth aspects and a lid.

[0077] (8) A package according to an eighth aspect of the present disclosure includes the package according to the seventh aspect and an electronic component.

[0078] The invention according to the present disclosure has been described above based on the drawings and examples. However, the invention according to the present disclosure is not limited to the above-described embodiments. In other words, the invention according to the present disclosure can be modified in various ways within the scope of the present disclosure, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the invention according to the present disclosure. In other words, it should be noted that a person skilled in the art can easily make various modifications or corrections based on the present disclosure. It should also be noted that these modifications or corrections are included in the scope of the present disclosure.

[0079] DESCRIPTION OF SYMBOLS 100, 100B, 100C... Wiring substrate 110... Base 120... Frame 130... Insulating base 150... Connection electrode 170... Wiring conductor 171... Via conductor 171A... First via conductor 171B... Second via conductor 172... External electrode 172A... First external electrode 172B... Second external electrode 173... Frame-shaped metallization layer (metallization layer) 173X... Outer region 174... In-frame conductor 174A... First portion 174B... Second portion 174P... Outer end portion 175... Relay conductor 176... Connection wiring 177... Internal wiring 200... Lid 300... Package 400... Piezoelectric vibration element 410... Bonding material 500, 500B... Piezoelectric device

Claims

1. A wiring board comprising: an insulating base including a base having a first surface and a second surface opposite the first surface, and a frame portion located on the outer edge of the first surface; a metallization layer located on the upper surface of the frame portion; external electrodes located on the second surface; and wiring conductors connecting the metallization layer and the external electrodes, wherein the wiring conductors include intra-frame conductors located inside the frame portion, and the intra-frame conductors and the metallization layer are connected in an outer region that is a region on the outer edge side of the metallization layer.

2. The wiring board according to claim 1, wherein the outer region is a region ranging from the outer edge of the metallization layer to a distance one-third of the width of the metallization layer.

3. The wiring board according to claim 1 or 2, wherein the inner-frame conductor has a first portion that extends mainly inward from the connection portion with the metallized layer toward the inside of the frame portion.

4. The wiring board according to claim 3, wherein the length of said first portion in the width direction of said frame is at least half the width of said frame.

5. The wiring board according to any one of claims 1 to 4, wherein the inner-frame conductor is connected to an outer end of the metallized layer.

6. The wiring board according to any one of claims 1 to 5, wherein the outer ends of the inner-frame conductors are exposed on the outer surface of the frame.

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

8. An electronic device comprising the package according to claim 7 and an electronic component.

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