Wiring board, package and piezoelectric device

Abstract

To ensure connection reliability and further miniaturization in packages that can accommodate elements of various sizes.SOLUTION: A wiring board has a base having a first surface, at least one staircase section located on the first surface and having a plurality of stepped surfaces, and a plurality of connecting electrodes, which are connected to separate terminals of the element. The plurality of connecting electrodes each have a first part located on a plurality of stepped surfaces and a second part connecting the plurality of first parts.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a wiring board, a package, and a piezoelectric device. [Background technology]

[0002] Prior art document 1 discloses a package for housing a piezoelectric vibrator, in which a step is provided inside the package, and electrodes of piezoelectric vibrators of various sizes can be connected. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3770607 Summary of the Invention [Problem to be solved by the invention]

[0004] Thus, in packages that accommodate elements of various sizes, there is a demand for further miniaturization while ensuring connection reliability. [Means for solving the problem]

[0005] A wiring board according to one embodiment of the present disclosure comprises a base having a first surface, at least one step portion located on the first surface and having a plurality of step surfaces, and a plurality of connection electrodes connected to separate terminals of an element, each of the plurality of connection electrodes having a first portion located on the plurality of step surfaces and a second portion connecting the plurality of first portions to each other.

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

[0007] A piezoelectric device according to one aspect of the present disclosure includes the above package and a piezoelectric vibration element. Effect of the Invention

[0008] One aspect of the present disclosure enables further miniaturization of a package capable of accommodating elements of various sizes while ensuring connection reliability. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is an exploded perspective view of a package according to a first embodiment of the present disclosure. [Diagram 2] 1 is a top view of a wiring board according to a first embodiment of the present disclosure. [Diagram 3] 1 is a cross-sectional view of a piezoelectric device according to a first embodiment of the present disclosure. [Figure 4] FIG. 11 is a perspective view of a wiring board according to a second embodiment. [Diagram 5] FIG. 11 is a cross-sectional view of a wiring board according to a second embodiment. [Figure 6] FIG. 11 is a top view of a wiring board according to a third embodiment. [Figure 7] FIG. 11 is a perspective view of a wiring board according to a fourth embodiment. [Figure 8] FIG. 11 is a top view of a wiring board according to a fourth embodiment. [Figure 9] FIG. 11 is a cross-sectional view of a piezoelectric device according to a fourth embodiment. [Figure 10] FIG. 11 is a perspective view of a wiring board according to a fifth embodiment. [Figure 11] FIG. 13 is a top view of a wiring board according to a fifth embodiment. [Figure 12] FIG. 13 is a perspective view of a wiring board according to a sixth embodiment. [Figure 13] FIG. 13 is a top view of a wiring board according to a sixth embodiment. [Figure 14] FIG. 13 is a cross-sectional view of a piezoelectric device according to a sixth embodiment. [Figure 15] FIG. 13 is a perspective view of a wiring board according to a seventh embodiment. [Figure 16] 13A and 13B are a top view and a cross-sectional view of a wiring board according to a seventh embodiment. [Figure 17] FIG. 13 is a perspective view of a wiring board according to an eighth embodiment. [Figure 18] 13A and 13B are a top view and a cross-sectional view of a wiring board according to an eighth embodiment. [Figure 19] FIG. 13 is a perspective view of a wiring board according to a ninth embodiment. [Figure 20] 13A and 13B are a top view and a cross-sectional view of a wiring board according to a ninth embodiment. [Figure 21] 13 is a cross-sectional view of a wiring board according to another aspect of the ninth embodiment. FIG. [Figure 22] FIG. 23 is a perspective view of a wiring board according to a tenth embodiment. [Figure 23] 13A and 13B are a top view and a cross-sectional view of a wiring board according to a tenth embodiment. [Figure 24] FIG. 23 is a perspective view of a wiring board according to an eleventh embodiment. [Diagram 25] 13A and 13B are a top view and a cross-sectional view of a wiring board according to an eleventh embodiment. [Figure 26] FIG. 23 is a perspective view of a wiring board according to a twelfth embodiment. [Figure 27] 23A and 23B are a top view and a cross-sectional view of a wiring board according to a twelfth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [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.

[0011] In the following description, the distinction between up and down is for convenience and does not limit the up and down when the wiring board, package, and piezoelectric device are actually used. In this specification, the surface of the wiring board 100 on which the piezoelectric vibration element 400 is mounted is defined as the upper surface. In the drawings, the positive direction of the Z axis is the upward direction. The X axis is the long axis direction of the wiring board 100, and the Y axis is an axis perpendicular to the X axis and the Z axis.

[0012] Fig. 1 is an exploded perspective view of an exemplary package 300 of the present disclosure. Fig. 2 is a top view of an exemplary wiring board 100 of the present disclosure. Fig. 3 is a cross-sectional view of an exemplary piezoelectric device 500 of the present disclosure. Fig. 3 is a cross-sectional view of the wiring board 100 shown in Fig. 2 taken along line III-III, with a piezoelectric vibration element 400 and a lid 200 added thereto.

[0013] 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.

[0014] The wiring board 100 has a base portion 110, a stepped portion 120, a pillow portion 130, a frame portion 140, and wiring conductors located on the surface and inside of the wiring board 100.

[0015] The base 110 may be a flat insulator having a first surface 111 and a second surface 112 located opposite to the first surface 111. The stepped portion 120 may be a stepped insulator located on the first surface 111 and having a plurality of step surfaces 121 and a plurality of step side surfaces 122. The step side surface 122 is a surface connecting the step surface 121 and the step surface 121, or the step surface 121 and the first surface 111. The pillow portion 130 may be a stepped insulator located opposite the stepped portion 120 on the first surface 111. The pillow portion 130 has a plurality of pillow portion step surfaces 131 corresponding to each step surface 121 of the stepped portion 120. The height of the pillow portion step surface 131 may be approximately the same as the height of the corresponding step surface 121. Alternatively, the height of the pillow portion step surface 131 may be approximately the same as the upper surface of the connection electrode 150 (described later) located on the corresponding step surface 121. Furthermore, the height of the pillow portion step surface 131 may be the height including the thickness of the connection electrode 150 and the bonding material 410 .

[0016] The step portion 120 and the pillow portion 130 may be integral with the base portion 110. In other words, the base portion 110 may have the step portion 120 protruding from the first surface 111 and the pillow portion 130 protruding from the first surface 111.

[0017] The frame portion 140 is located on the first surface 111, surrounding the mounting region 180, the stepped portion 120, and the pillow portion 130. By providing the frame portion 140 on the wiring board 100, it is possible to protect elements and the like in a state in which the cover body 200 is not provided. The frame portion 140 may also be integral with the base portion 110. In a plan view, the outer edge of the frame portion 140 may overlap the outer edge of the base portion 110.

[0018] The dashed and dotted lines in Fig. 2 show the outer edges of the piezoelectric vibration elements 400 as imaginary lines when three different sizes of piezoelectric vibration elements 400 are arranged on the wiring board 100. The mounting area 180 of the wiring board 100 may be an area that overlaps with the piezoelectric vibration elements 400 when viewed in a plan view on the wiring board 100. That is, it may be an area shown by the dashed and dotted lines in Fig. 2. Alternatively, the mounting area 180 may be an area surrounded by imaginary lines connecting alignment marks (not shown) used when arranging the piezoelectric vibration elements 400. The mounting area 180 may be defined according to the size of the piezoelectric vibration elements 400 to be mounted.

[0019] The base 110, the step portion 120, the pillow portion 130, and the frame portion 140 may be made of an insulating inorganic material. The insulating inorganic material includes ceramics such as aluminum oxide sintered body (alumina ceramics), aluminum nitride sintered body, mullite sintered body, or glass ceramic sintered body. The base 110, the step portion 120, the pillow portion 130, and the frame portion 140 may be integrally formed, or may be made of a plurality of laminated insulating layers or a single insulating layer.

[0020] The wiring conductors included in the wiring board 100 include a connection electrode 150 , a first through conductor 171 A, a second through conductor 171 B, an external electrode 172 , and a frame-shaped metallization layer 173 .

[0021] The connection electrode 150 is an electrode electrically connected to a terminal of the piezoelectric vibration element 400. In the attached drawings, the connection electrode 150 is indicated by dot hatching in the plan view and the perspective view. Each of the connection electrodes 150 has a first portion 151 located on the step surface 121 of the staircase portion 120, a second portion 152 connecting the first portions 151, and a third portion 153 located on the first surface 111 and connecting to the second portion 152. When the connection electrode 150 has the third portion, the second portion 152 may be a portion connecting the first portion 151 and the third portion 153. The second portion 152 may be defined as a portion located on the step side surface 122 of the staircase portion 120. Each of the connection electrodes 150 has a continuous band shape and extends from the step surface 121 located at the top of the staircase portion 120 to the first surface 111.

[0022] By having the third portion 153, the wiring board 100 can also mount the piezoelectric vibration element 400 on the first surface 111, making it possible to further reduce the height. As shown in FIG. 3, the upper surface of the third portion 153 of the connection electrode 150 may be at the same height as the first surface 111. By having the upper surface of the third portion 153 at the same height as the first surface 111, it is possible to further reduce the height. The surface of the third portion 153 may be covered with a plating layer of nickel and / or gold, similar to other exposed conductors. In this case, it may protrude from the first surface 111 by the thickness of the plating layer. The plating layer will be described in detail later.

[0023] The external electrodes 172 include a first external electrode 172A and a second external electrode 172B. 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 the connection electrodes 150 and the number of the 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 cover 200. The first external electrode 172A and the second external electrode 172B may each be located along a diagonal line of the second surface 112. The first external electrode 172A and the second external electrode 172B may extend from the second surface 112 of the base 110 to a side surface (including a corner between the side surfaces).

[0024] 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 board.

[0025] The first through conductor 171A is a wiring that penetrates the base 110 and, if necessary, the stepped portion 120, and connects the connection electrode 150 and the first external electrode 172A. The second through conductor 171B is a wiring that penetrates the frame portion 140 and the base 110, and connects the frame-shaped metallization layer 173 and the second external electrode 172B. In the wiring board 100, the first through conductor 171A connects the first portion 151 located on the top step surface 121 to the first external electrode 172A. The top step surface 121 may be designed to have a larger area in a plan view than the other step surfaces 121 in order to mount a larger-sized element among the mountable piezoelectric vibration elements 400. In this case, by connecting the first through conductor 171A to the first portion 151 located on the top step surface 121, which has a larger area, the ratio of the size of the first through conductor 171A to the first portion 151 when viewed from above becomes smaller. This can reduce the influence of a so-called via protrusion, that is, a portion of the connection electrode 150 that overlaps with the first through conductor 171A that protrudes upward.

[0026] The frame-shaped metallization layer 173 is a conductive layer located on the upper surface of the frame portion 140. The frame-shaped metallization layer 173 is joined to the lid body 200 using a sealing material (not shown) such as a gold-tin alloy (AuSn) or silver solder.

[0027] The frame-shaped metallized layer 173, the exposed surface of the connection electrode 150, and the exposed surface of the external electrode 172 may be covered with a plating layer of nickel and / or gold. For example, the exposed surface may be nickel-plated to a thickness of 1 to 20 μm, and gold plating may be applied to a thickness of 0.1 to 3.0 μm on the nickel-plated layer. This can reduce the possibility of oxidation corrosion of the wiring conductor surface. Also, the connection between the frame-shaped metallized layer 173 and the lid 200, which is a metal conductor, can be easily and firmly established.

[0028] The lid 200 is made of a conductive metal and is joined to the frame-shaped metallization layer 173 to hermetically seal the package 300. The lid 200 may be grounded. More specifically, as shown in FIG. 8, the frame-shaped metallization layer 173 is connected to the second external electrode 172B of the wiring board 100 via the second penetrating conductor 171B. The second external electrode 172B is grounded, so that the lid 200 can obtain a ground potential. The grounding of the lid 200 can reduce the propagation of external noise into the package 300.

[0029] In the first embodiment, the wiring board 100 includes two step portions 120, one pillow portion 130, and two connection electrodes 150. The two step portions 120 have step surfaces 121 of the same height, and are arranged along one side of the wiring board 100. The two step portions 120 are arranged spaced apart from each other at positions away from the frame portion 140. The pillow portion 130 is arranged adjacent to the frame portion 140 at a position opposite the step portion 120. The pillow portion 130 may be integral with the frame portion 140.

[0030] The two connection electrodes 150 are each connected to a different terminal of the piezoelectric vibration element 400. The two connection electrodes 150 are each located on a different staircase portion 120, cover the entire staircase portion 120 in a plan view, and overlap a part of the first surface 111.

[0031] As shown in FIG. 2, the piezoelectric vibration element 400 can be mounted on different step surfaces 121 or the first surface 111 depending on its size. FIG. 3 shows an example in which the piezoelectric vibration element 400 is mounted on the step surface 121 located at the lower of the two step surfaces of the staircase portion 120 via a bonding material 410. The bonding material 410 is a conductive bonding material. The bonding material 410 may be, for example, a resin to which conductive particles such as silver are added. When the bonding material 410 is a thermosetting material, the bonding material 410 is applied to the connection electrode 150 in advance, and the piezoelectric vibration element 400 is positioned and placed relative to the connection electrode 150 (bonding material 410) and heated. As a result, the piezoelectric vibration element 400 is connected to the connection electrode 150 via the bonding material 410.

[0032] In the wiring board 100, the two step portions 120 are spaced apart from each other, so that the possibility of the electrodes of the piezoelectric vibration element 400 being short-circuited via the bonding material 410 can be reduced.

[0033] In addition, in the wiring board 100, the frame 140 and the first portion 151 located on the step surface 121 of the uppermost step of the staircase portion 120 are separated from each other in a plan view. This allows the end of the connection electrode 150 on the frame 140 side to be visible in a top view, making it easy to use as an alignment mark when arranging elements in image processing or the like. In addition, the bonding material 410 can be prevented from creeping up the inner wall of the frame 140 and reaching the sealing surface, thereby reducing the possibility of deterioration of sealing performance.

[0034] As described above, the wiring board 100 according to the present disclosure includes the base portion 110 having the first surface 111, at least one stepped portion 120 located on the first surface 111 and having a plurality of step surfaces 121, and a plurality of connection electrodes 150 connected to separate terminals of the piezoelectric vibration element 400. Each of the plurality of connection electrodes 150 has a first portion 151 located on the plurality of step surfaces 121 and a second portion 152 connecting the plurality of first portions 151 to each other.

[0035] By providing the stepped portion 120, when mounting the piezoelectric vibration elements 400 of various sizes, the piezoelectric vibration elements 400 can be mounted at appropriate positions in the planar direction and the vertical direction.

[0036] Moreover, since the second portion 152 of the connection electrode 150 is also located on the step side surface 122 of the staircase portion, when the connection electrode 150 and the piezoelectric vibration element 400 are joined using the joining material 410, electrical continuity is also possible on the step side surface 122. Therefore, the area of ​​the connection electrode 150 extending in the planar direction can be reduced, and further miniaturization can be achieved while maintaining connection reliability.

[0037] Furthermore, in a configuration having a plurality of separate connection electrodes corresponding to the piezoelectric vibration elements 400 of various sizes (a configuration having only the first section 151), it is necessary to provide internal wiring connecting each connection electrode to an external electrode. However, since the wiring board 100 has a series of connection electrodes 150 that connect to elements of various sizes, they can be connected to the external electrodes by a single through conductor. This allows the internal wiring to be simplified, improving the flatness of the connection electrodes 150 and improving the strength of the board. Furthermore, by simplifying the internal wiring, it is easier to ensure spacing between the wiring, allowing the board to be made smaller and thinner while maintaining insulation.

[0038] Moreover, the wiring board 100 includes a pillow section 130 having a pillow section step surface 131 that corresponds to the height of the step surface 121 of the staircase section 120. This allows the piezoelectric vibration elements 400 of various sizes to be fixed in the correct posture. In addition, in the piezoelectric device 500, the pillow section 130 is at an appropriate height position for each of the piezoelectric vibration elements 400 of various sizes, thereby reducing the possibility of the piezoelectric vibration elements 400 being damaged when an impact is applied to the piezoelectric device 500.

[0039] In the first embodiment, an example in which the wiring board 100 includes the frame portion 140 has been described, but the wiring board 100 does not necessarily have to include the frame portion 140. In this case, the lid body 200 may have a cap shape having a recess capable of accommodating the stepped portion 120 and the piezoelectric vibration element 400. The cap-shaped lid body 200 can be connected to a frame-shaped metallized layer 173 provided on the first surface 111 of the wiring board 100 via a sealing material.

[0040] (Method of Manufacturing Wiring Board) Next, an example of a method for manufacturing the wiring board 100 will be described.

[0041] First, through holes are formed in the ceramic green sheets that will become the base 110, the stepped portion 120, the pillow portion 130, and the frame portion 140, and a conductor is injected into the through holes to form the first through conductors 171A and the second through conductors 171B.

[0042] Then, a metallization paste is applied using a mask to the positions of the connection electrodes 150 and the frame-shaped metallization layer 173 on the upper surface of the ceramic green sheet. A metallization paste is applied using a mask to the positions of the external electrodes 172 on the lower surface side of the ceramic green sheet. Furthermore, a metallization paste is applied to the positions of the internal wiring including the wiring connecting the external electrodes 172 to each other on the lower surface side of the ceramic green sheet. Furthermore, a ceramic paste is applied to the lower surface side of the ceramic green sheet to cover the internal wiring connecting the external electrodes 172 to each other. The application of the metallization paste and the application of the ceramic paste are performed by, for example, screen printing.

[0043] A ceramic green sheet with metallization paste applied on both sides is placed on a flat plate and pressed from above by a pressing tool having projections and recesses corresponding to the stepped portion 120, the pillow portion 130, the frame portion 140, and the connection electrodes 150. This forms the stepped portion 120, the pillow portion 130, the frame portion 140, and the connection electrodes 150 located on the stepped portion 120.

[0044] Furthermore, the metallization paste and ceramic paste become planar on the lower surface side of the ceramic green sheet, and external electrodes 172 connected via internal wiring are formed. Then, a firing process is performed at a temperature of 1300 to 1600° C., thereby obtaining the wiring board 100. Thereafter, plating process, attachment of the piezoelectric vibration element 400, joining of the lid 200, etc. are performed as necessary, thereby obtaining the piezoelectric device 500.

[0045] As described above, when the pressing jig is used for formation, a wiring conductor 171C including a plate-shaped conductor 1711 as shown in the cross-sectional view of FIG. 23 can be formed as a wiring connecting the frame-shaped metallization layer 173 and the second external electrode 172B. The plate-shaped conductor 1711 is located within the frame portion 140. The plate-shaped conductor 1711 may be located within the stepped portion 120 or the pillow portion 130. The plate-shaped conductor 1711 may be connected to an internal wiring such as a through conductor 1712 located within the base portion 110. In other words, the wiring conductor 171C may include the plate-shaped conductor 1711 and the through conductor 1712.

[0046] The plate-shaped conductor 1711 can be formed by applying a metallization paste (conductor layer) that will become the plate-shaped conductor 1711 to a ceramic green sheet, applying a ceramic paste onto the conductor layer, and then pressing with a pressing tool. Since the plate-shaped conductor 1711 can be formed thin, the thickness of the frame 140 can be made thin, allowing for further miniaturization.

[0047] Furthermore, when forming using a pressing jig, the recessed corners of the pillow portion 130 may be rounded as shown in the cross-sectional view of Fig. 23. This reduces the possibility of cracks starting from the corners. Rounding the recessed corners is easily possible by changing the shape of the pressing jig.

[0048] Alternatively, wiring board 100 may be fabricated by laminating a plurality of ceramic green sheets having through holes at appropriate positions, injecting a conductor, applying a metallization paste, and then firing 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, the same reference numerals are given to components having the same functions as those described in the first embodiment, and the explanations thereof will not be repeated. The same applies to the other embodiments described below.

[0050] Fig. 4 is a perspective view of a wiring board 100A according to embodiment 2. The diagram indicated by reference numeral 5001 in Fig. 5 is a cross-sectional view of a piezoelectric vibration element 400 added to the cross section taken along the arrow VV line in Fig. 4. The diagram indicated by reference numeral 5002 in Fig. 5 is a cross-sectional view of a wiring board 100A2, which is another embodiment of the wiring board 100A, and a piezoelectric vibration element 400.

[0051] Wiring board 100A and wiring board 100A2 differ from wiring board 100 of embodiment 1 in that staircase portion 120A and staircase portion 120A2 are entirely made of a conductive metal. Other points are the same as wiring board 100 of embodiment 1.

[0052] 5 has a staircase portion 120A made of a conductive metal. In this case, the surfaces of step surface 121 and step side surface 122 of staircase portion 120A are first portion 151 and second portion 152 of connection electrode 150A. Third portion 153A of connection electrode 150 is connected to staircase portion 120A. The top surface of third portion 153A is flush with first surface 111.

[0053] By making the staircase section 120A out of a conductive metal, it is possible to reduce the conduction resistance in the connection between the piezoelectric vibration element 400 and the external electrode 172. More specifically, since the staircase section 120A is an integrally formed conductive metal, it is possible to increase the cross-sectional area of ​​the conduction path regardless of which step surface of the staircase section 120A the piezoelectric vibration element 400 is connected to. This allows the piezoelectric vibration element 400 and the external electrode 172 to be connected with low conduction resistance.

[0054] The wiring board 100A2 indicated by reference numeral 5002 in Fig. 5 also has a staircase portion 120A made of a conductive metal. The surfaces of step faces 121 and step side faces 122 of the staircase portion 120A2 are the first portion 151 and the second portion 152 of the connection electrode 150A. The staircase portion 120A2 has three step faces 121. At least a part of the staircase portion 120A2 is located in a recess provided in the base portion 110, and the lowest step face 121 of the three step faces 121 is flush with the first surface 111 of the base portion 110.

[0055] In the wiring board 100A2, the first through conductor 171A connects the first portion 151 located on the lowest step surface 121 to the first external electrode 172A. The lowest step surface 121 is located away from the outer edge of the wiring board 100A2 in the wiring board 100A2. When the lid is joined in the manufacture of the piezoelectric device or when the piezoelectric device is mounted, a large thermal stress is applied to the corners of the wiring board 100A2. By positioning the first through conductor 171A at a position away from the corners to which a large stress is applied, the possibility of cracks occurring at the through conductor origin due to stress is reduced. This improves the connection reliability between the first through conductor 171A and the connection electrode 150, and between the first through conductor 171A and the first external electrode 172A.

[0056] [Embodiment 3] The third embodiment of the present disclosure will be described below. Fig. 6 is a top view of a wiring board 100B according to the third embodiment.

[0057] The wiring board 100B includes two step portions 120 and two pillow portions 130. The two step portions 120 of the wiring board 100B have step surfaces 121 at the same height, and are located along a diagonal line of the first surface 111 of the wiring board 100B. The pillow portions 130 are located opposite each of the step portions 120. The other points are the same as those of the wiring board 100 of the first embodiment.

[0058] This configuration makes it possible to realize a substrate capable of mounting elements having terminals along diagonals.

[0059] [Embodiment 4] A fourth embodiment of the present disclosure will be described below. Fig. 7 is a perspective view of a wiring board 100C according to the fourth embodiment. Fig. 8 is a top view of the wiring board 100C. Fig. 9 is a cross-sectional view of a piezoelectric device 500C. Fig. 9 is a cross-sectional view of the wiring board 100C shown in Fig. 8 taken along line IX-IX, with a piezoelectric vibration element 400 and a lid 200 added.

[0060] The wiring substrate 100C has a stepped portion 120C and a connection electrode 150C. The piezoelectric device 500C includes the wiring substrate 100C, a piezoelectric vibration element 400, and a lid 200.

[0061] In a plan view of wiring board 100C, first portion 151 of connection electrode 150C has a length perpendicular to the arrangement direction of multiple step surfaces 121 that becomes shorter toward the center of wiring board 100C. Furthermore, the length of third portion 153 of connection electrode 150C is shorter than the length of first portion 151 located on the lowest step surface 121. With this configuration, the area of ​​connection electrode 150C on each step surface 121 can be adjusted to the size of the element to be mounted, and the area of ​​unnecessary metal portions of connection electrode 150C that do not contribute to conduction with bonding material 410 can be reduced.

[0062] In a plan view, the side of each connection electrode 150C facing another connection electrode 150C has a straight line shape, and the opposite side of the side has a stepped shape. By having such a stepped shape, for example, the outer corner of the first portion 151 can be used as an alignment mark when arranging the piezoelectric vibration element 400 in image processing or the like.

[0063] The step portion 120C of the wiring board 100C has a shape in which its outer edge overlaps with the connection electrode 150C in a plan view, but the connection electrode 150C of the fourth embodiment may be located on the step portion 120 of the first embodiment. Even with this configuration, the above-mentioned effects can be obtained. Since the outer edge of the step portion 120C has a shape in which it overlaps with the connection electrode 150C in a plan view, the visibility is further improved when used as an alignment mark when arranging the piezoelectric vibration element 400 in image processing or the like.

[0064] In addition, in the wiring board 100C, the first through conductor 171A connects the third portion 153 and the first external electrode 172A. The third portion 153 is located in a position in the wiring board 100C away from the outer edge of the wiring board 100C. When the lid 200 is joined in the manufacture of the piezoelectric device 500C or when the piezoelectric device 500C is mounted, a large thermal stress is applied to the corners of the wiring board 100C. By positioning the first through conductor 171A at a position away from the corners to which a large stress is applied, the possibility of cracks occurring at the through conductor origin due to stress is reduced. This improves the connection reliability between the first through conductor 171A and the connection electrode 150, and between the first through conductor 171A and the first external electrode 172A.

[0065] [Embodiment 5] The fifth embodiment of the present disclosure will be described below. Fig. 10 is a perspective view of a wiring board 100D according to the fifth embodiment. Fig. 11 is a top view of the wiring board 100D.

[0066] The wiring board 100D has a stepped portion 120D and a connection electrode 150D. In a plan view of the wiring board 100D, the length of the first portion 151 of the connection electrode 150D perpendicular to the arrangement direction of the multiple step surfaces 121 becomes shorter toward the center of the wiring board 100D. Furthermore, the length of the third portion 153 of the connection electrode 150D is shorter than the length of the first portion 151 located on the lowest step surface 121. With this configuration, the area of ​​the connection electrode 150D on each step surface 121 can be adjusted to the size of the element to be mounted, and unnecessary metal parts in the connection electrode 150D that do not contribute to conduction with the bonding material 410 can be reduced.

[0067] In plan view, the side of each connection electrode 150D facing another connection electrode 150D and the side opposite to the side facing the other connection electrode 150D both have a stepped shape. By having such a stepped shape, for example, the outer corner of the first portion 151 can be used as an alignment mark when arranging the piezoelectric vibration element 400 in image processing or the like.

[0068] Furthermore, the distance between the connection conductors located on the staircase portion 120 is greater than in the fourth embodiment. This reduces the possibility of a short circuit between the connection conductors when the bonding material 410 flows out between the staircase portions 120.

[0069] [Embodiment 6] The sixth embodiment of the present disclosure will be described below. Fig. 12 is a perspective view of a wiring board 100E according to the sixth embodiment. Fig. 13 is a top view of the wiring board 100E. Fig. 14 is a cross-sectional view of a piezoelectric device 500E. Fig. 14 is a cross-sectional view of the wiring board 100E shown in Fig. 13 taken along line XIV-XIV, with a piezoelectric vibration element 400 and a lid 200 added.

[0070] In a plan view of the wiring substrate 100E, the first portion 151 of the connection electrode 150 is smaller than the step surface 121 of the staircase portion 120. In other words, the outer edge portion of the step surface 121 of the staircase portion 120 is exposed. Also, as shown in Fig. 14, the upper surface of the first portion 151 is flush with the step surface 121 in a portion where the first portion 151 is not located. Furthermore, the upper surface of the third portion 153 is flush with the first surface 111.

[0071] With this configuration, the outer edge of the connection electrode 150 is protected by the stepped portion 120 or the base portion 110, which reduces the possibility of the connection electrode 150 peeling off. Also, a further reduction in thickness is possible.

[0072] [Embodiment 7] The seventh embodiment of the present disclosure will be described below. Fig. 15 is a perspective view of a wiring board 100F according to the seventh embodiment. Fig. 16 is a top view and a cross-sectional view of the wiring board 100F.

[0073] The wiring board 100F includes one stepped portion 120, one pillow portion 130, and two connection electrodes 150. In the wiring board 100F, the two connection electrodes 150 are located on one stepped portion 120. The stepped portion 120 is connected to the frame portion 140. The pillow portion 130 is also connected to the frame portion 140.

[0074] Since there is only one each of the stepped portion 120 and the pillow portion 130, and they are arranged opposite each other, the arrangement of the hot parts of the board thickness in the wiring board 100F is well balanced, and distortion due to stress is reduced. Although both the stepped portion 120 and the frame portion 140 of the wiring board 100F are connected to the frame portion 140, the effect of reducing distortion due to the stress can be obtained even if they are not connected to the frame portion 140.

[0075] The strength of the wiring board 100F can be further improved by connecting the step portion 120 and / or the pillow portion 130 to the frame portion 140. The step portion 120 or the pillow portion 130 may be connected only to the short side of the frame portion 140, like the pillow portion 130 in the wiring board 100 of the embodiment. The step portion 120 or the pillow portion 130 is connected to both the short side and the long side of the frame portion 140, like the wiring board 100F of the seventh embodiment, so that the strength of the board is further improved.

[0076] Furthermore, even in the case where there are two staircase portions 120, as in the wiring board 100 of the first embodiment, each of the two staircase portions 120 may be connected to the frame portion 140. Each of the two staircase portions 120 may be connected to only one of the short sides or long sides of the frame portion 140, or may be connected to both the short side and the long side. By connecting the staircase portions 120 to both the short side and the long side of the frame portion 140, the strength of the board is further improved.

[0077] Furthermore, each step surface 121 and the first surface 111 of the staircase portion 120 may have a recess between the two connection electrodes 150. When multiple connection electrodes 150 are located on a common staircase portion 120, having a recess between the connection electrodes 150 reduces the possibility of short-circuiting between the electrodes via the bonding material 410 used to bond the elements. Furthermore, the recess may be formed to a depth that reaches the first surface 111 and a length in the X-axis direction that is equal to or longer than the length of the staircase portion, thereby realizing a shape of the staircase portion 120 that connects to both the short side and the long side of the frame portion 140.

[0078] [Embodiment 8] The eighth embodiment of the present disclosure will be described below. Fig. 17 is a perspective view of a wiring board 100G according to the eighth embodiment. Fig. 18 is a top view and a cross-sectional view of the wiring board 100G.

[0079] The wiring board 100G includes one stepped portion 120, one pillow portion 130, and two connection electrodes 150. The stepped portion 120 is connected to the frame portion 140. The pillow portion 130 is also connected to the frame portion 140. The wiring board 100G has a recess 190 between the stepped portion 120 and the frame portion 140.

[0080] 17 and 18, the recess 190 is formed over the entire connection portion between the stepped portion 120 and the frame portion 140, but is not limited to this example. The recess 190 may be located at least between each connection electrode 150 and the frame portion 140. For example, the wiring board 100G may include two recesses 190, and each recess 190 may be located between each connection electrode 150 and the frame portion 140, as in the wiring board 100I shown in FIGS. 22 and 23. Alternatively, the recess 190 may extend to the long side of the frame portion 140 in a top view.

[0081] In the example shown in Figures 17 and 18, the bottom of the recess 190 is approximately the same as the first surface 111, but this is not limited to this example, and the depth of the recess 190 may be shallower than the example shown in Figures 17 and 18, such as the wiring board 100I shown in Figures 22 and 23.

[0082] Providing the recess 190 reduces the possibility that the bonding material 410 used when mounting the piezoelectric vibration element 400 will creep up along the inner wall of the frame 140 and reach the sealing surface, thereby deteriorating the sealing performance. If the recess 190 extends to the long side of the frame 140, the possibility that the bonding material 410 will creep up along the inner wall on the long side of the frame 140 can also be reduced.

[0083] Furthermore, each step surface 121 and the first surface 111 of the staircase portion 120 may have a recess between two connection electrodes 150. When multiple connection electrodes 150 are located on a common staircase portion 120, having a recess between the connection electrodes 150 can reduce the possibility of short-circuiting between the electrodes via the bonding material 410 used to bond the elements.

[0084] [Embodiment 9] A ninth embodiment of the present disclosure will be described below. Fig. 19 is a perspective view of a wiring board 100H according to the ninth embodiment. Fig. 20 is a top view and a cross-sectional view of the wiring board 100H.

[0085] Wiring board 100H has second frame portion 141, which is lower in height than frame portion 140, inside frame portion 140. In wiring board 100H, a part of second frame portion 141 forms a part of step portion 120 and a part of pillow portion 130. Connection electrode 150 is located from the upper surface of second frame portion 141 to first surface 111.

[0086] The number of frame portions located inside frame portion 140 is not limited to one, and wiring board 100H may have multiple frame portions. As in wiring board 100K shown in FIG. 26, multiple frame portions may each form a part of step portion 120 and a part of pillow portion 130.

[0087] This configuration can further improve the strength compared to wiring board 100G of the eighth embodiment.

[0088] 21 is a cross-sectional view of a wiring board 100HA which is another embodiment of the wiring board 100H. As in the wiring board 100HA, the connection electrodes 150 may protrude from the upper surface of the stepped portion 120 and the first surface 111. In this case, the height of each pillow portion step surface 131 of the pillow portion 130 may be set to a height corresponding to the upper surface of the corresponding connection electrode 150.

[0089] [Embodiment 10] A tenth embodiment of the present disclosure will be described below. Fig. 22 is a perspective view of a wiring board 100I according to the tenth embodiment. Fig. 23 is a top view and a cross-sectional view of the wiring board 100I.

[0090] Wiring board 100I differs from wiring board 100H of embodiment 9 in that wiring board 100I has a recess 190 between stepped portion 120 and frame portion 140. Wiring board 100I also differs from wiring board 100G of embodiment 8 in that wiring board 100I has two recesses 190, each of which is located between connecting electrode 150 and frame portion 140. Furthermore, the wiring connecting frame-shaped metallized layer 173 and second external electrode 172B is wiring conductor 171C including plate-shaped conductor 1711.

[0091] Providing the recess 190 reduces the possibility that the bonding material 410 used when mounting the piezoelectric vibration element 400 will creep up along the inner wall of the frame 140 and reach the sealing surface, thereby deteriorating the sealing performance. In addition, when the wiring board 100I has two recesses 190, the possibility of a short circuit caused by the bonding materials 410 arranged on the connection electrodes 150 joining together inside the recesses can be reduced.

[0092] 22 and 23, each recess 190 may have an L-shape extending toward the long side of frame 140 when viewed from above. This configuration can reduce the possibility that bonding material 410 creeps up along the inner wall of frame 140 even on the long side.

[0093] Furthermore, since the wiring conductor 171C includes the thin plate-like conductor 1711, the thickness of the frame 140 can be reduced, leading to a further miniaturization.

[0094] By having the recess 190, the wiring board 100I can improve the board strength while reducing the possibility that the bonding material 410 used when mounting the piezoelectric vibration element 400 will creep up the inner wall of the frame portion 140 and short-circuit with the frame-shaped metallization layer 173 at ground potential.

[0095] [Embodiment 11] An eleventh embodiment of the present disclosure will be described below. Fig. 24 is a perspective view of a wiring board 100J according to the eleventh embodiment. Fig. 25 is a top view and a cross-sectional view of the wiring board 100J.

[0096] The wiring board 100J has a stepped portion 120J and a connection electrode 150J. In a plan view of the wiring board 100J, a step surface 121 of the stepped portion 120 has an L-shape.

[0097] Since the step surface 121 of the staircase portion 120J has an L-shape, the inner wall of the frame portion located one step above acts as a dike that restricts the flow of the bonding material 410. This makes it possible to restrict the spread of the bonding material 410 when bonding the piezoelectric vibration element 400, and to improve the bonding strength. In addition, since the corners of the L-shape are highly visible, they can be advantageously used as alignment marks when arranging elements in image processing, etc.

[0098] [Embodiment 12] A twelfth embodiment of the present disclosure will be described below. Fig. 26 is a perspective view of a wiring board 100K according to the twelfth embodiment. Fig. 27 is a top view and a cross-sectional view of the wiring board 100K.

[0099] The wiring board 100K has a second frame portion 141 and a third frame portion 142 inside the frame portion 140. Parts of the second frame portion 141 and the third frame portion 142 form part of the stepped portion 120 and part of the pillow portion 130. The connection electrode 150 is located from the upper surface of the second frame portion 141 to the first surface 111.

[0100] In a plan view of the wiring board 100K, the first portion 151 of the connection electrode 150 is located at a corner of the second frame portion 141 and a corner of the third frame portion 142, and has an L-shape.

[0101] This configuration can limit the spread of the bonding material 410 when bonding the piezoelectric vibration element 400, and can improve the bonding strength, similar to the wiring board 100J of the eleventh embodiment. In addition, the corners of each frame are highly visible, and can be advantageously used as alignment marks when arranging elements in image processing or the like.

[0102] 〔summary〕 A wiring board according to a first aspect of the present disclosure comprises a base having a first surface, at least one step portion located on the first surface and having a plurality of step surfaces, and a plurality of connection electrodes connected to separate terminals of an element, each of the plurality of connection electrodes having a first portion located on the plurality of step surfaces and a second portion connecting the plurality of first portions to each other.

[0103] The wiring board according to aspect 2 of the present disclosure is similar to aspect 1 above, but includes a plurality of step portions, each of which has a step surface of the same height and is positioned at a distance from one another, and each of which is located on a different step portion.

[0104] A wiring board according to a third aspect of the present disclosure is related to the first aspect, in that the plurality of connection electrodes are positioned side by side on one of the stepped portions.

[0105] The wiring board according to aspect 4 of the present disclosure is any one of aspects 1 to 3 above, further comprising at least one pillow portion positioned opposite the step portion, the pillow portion having a pillow portion step surface corresponding to the height of the step surface of the step portion.

[0106] A wiring board according to a fifth aspect of the present disclosure is based on any one of the first to fourth aspects, in which at least one of the plurality of step surfaces has an L-shape in plan view.

[0107] The wiring board according to aspect 6 of the present disclosure is any one of aspects 1 to 5 above, wherein, in a planar view, the length of the first portion perpendicular to the arrangement direction of the multiple step surfaces becomes shorter toward the center of the base.

[0108] A wiring board according to a seventh aspect of the present disclosure is any one of the first to sixth aspects, wherein the connection electrode has a third portion located on the first surface and connected to the second portion.

[0109] The wiring board according to an eighth aspect of the present disclosure is any one of the first to seventh aspects, wherein an upper surface of the first portion is flush with the step surface in a portion where the first portion is not located.

[0110] The wiring board according to a ninth aspect of the present disclosure is any one of the first to eighth aspects, further comprising, on the first surface, a mounting area on which the element is mounted and a frame portion positioned to surround the staircase portion.

[0111] The wiring board according to aspect 10 of the present disclosure is any one of aspects 1 to 9 above, in which the frame portion and the first portion located on the cross section of the uppermost step of the staircase portion among the multiple step surfaces are separated from each other in a planar view.

[0112] The wiring board according to an eleventh aspect of the present disclosure is any one of the first to ninth aspects, wherein the step portion is connected to the frame portion.

[0113] The wiring board according to a twelfth aspect of the present disclosure is the same as the eleventh aspect of the present disclosure, except that it has a recess located between the stepped portion and the frame portion.

[0114] The wiring board of aspect 13 of the present disclosure, in any of aspects 1 to 12 above, comprises an external electrode located on a second surface opposite the first surface, and a penetrating conductor penetrating the step portion and the base, and the penetrating conductor connects the first portion located on the lowest step surface of the multiple step surfaces to the external electrode.

[0115] The wiring board according to aspect 14 of the present disclosure, in any of aspects 1 to 12 above, comprises an external electrode located on a second surface opposite the first surface, and a penetrating conductor penetrating the step portion and the base, and the penetrating conductor connects the first portion located on the highest step surface among the multiple step surfaces to the external electrode.

[0116] A wiring board according to aspect 15 of the present disclosure is the wiring board of aspect 7 described in claim 7, further comprising an external electrode located on a second surface opposite the first surface and a through conductor penetrating the base, the through conductor connecting the third portion and the external electrode.

[0117] A package according to a sixteenth aspect of the present disclosure includes the wiring board according to any one of the first to fifteenth aspects above, and a lid.

[0118] A piezoelectric device according to a seventeenth aspect of the present disclosure includes the package of the sixteenth aspect and a piezoelectric vibration element.

[0119] 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-mentioned 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 the embodiments obtained by appropriately combining the technical means disclosed in the 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. [Explanation of symbols]

[0120] 100, 100A, 100A2, 100B, 100C, 100D, 100E, 100F, 100G, 100H, 100HA, 100I, 100J, 100K... Wiring board 110...Base 120, 120A, 120A2, 120C, 120D, 120J...Stairs 121... Step surface 122...Step side 130...pillow part 131... Pillow step surface 140...Frame section 141...Second frame part 142...Third frame section 150, 150A, 150C, 150D, 150J... Connection electrode 171A···First through conductor 171B Second through conductor 171C···Wiring conductor 172...external electrode 173...Frame-shaped metallized layer 180...Mounting area 190...Concave 200···Cover body 300··Package 400 Piezoelectric vibration element 410...Joining material 500, 500C, 500E... Piezoelectric devices

Claims

1. a base having a first surface; At least one step portion located on the first surface and having a plurality of step surfaces; a plurality of connection electrodes connected to separate terminals of the element; The wiring board, wherein each of the plurality of connection electrodes has a first portion located on the plurality of step surfaces and a second portion connecting the plurality of first portions to each other.

2. A plurality of staircases are provided. The plurality of step portions have step surfaces of the same height and are spaced apart from each other, The wiring board according to claim 1 , wherein the plurality of connection electrodes are located on different stepped portions.

3. The wiring board according to claim 1 , wherein the plurality of connection electrodes are positioned side by side on one of the stepped portions.

4. Further comprising at least one pillow portion located opposite the step portion, The wiring board according to claim 1 , wherein the pillow portion has a pillow step surface that corresponds to the height of the step surface of the staircase portion.

5. The wiring board according to claim 1 , wherein at least one of the plurality of step surfaces has an L-shape in a plan view.

6. The wiring board according to claim 1 , wherein in a plan view, the first portion has a length perpendicular to a direction in which the plurality of step surfaces are arranged, the length decreasing toward a center of the base portion.

7. The wiring board according to claim 1 , wherein the connection electrode has a third portion located on the first surface and connected to the second portion.

8. The wiring board according to claim 1 , wherein an upper surface of the first portion and the step surface in a portion where the first portion is not located are flush with each other.

9. The wiring board according to claim 1 , further comprising a frame portion on the first surface, the frame portion surrounding the step portion and a mounting area on which the element is mounted.

10. The wiring board according to claim 9 , wherein the frame portion and the first portion located on an uppermost step surface of the staircase portion among the plurality of step surfaces are spaced apart from each other in a plan view.

11. The wiring board according to claim 9 , wherein the step portion is connected to the frame portion.

12. The wiring board according to claim 11 , further comprising a recess located between the stepped portion and the frame portion.

13. an external electrode located on a second surface opposite to the first surface; a through conductor passing through the step portion and the base portion, The wiring board according to claim 1 , wherein the through conductor connects the first portion located on a lowermost step surface of the plurality of step surfaces to the external electrode.

14. an external electrode located on a second surface opposite to the first surface; a through conductor passing through the step portion and the base portion, The wiring board according to claim 1 , wherein the through conductor connects the first portion located on an uppermost step surface of the plurality of step surfaces to the external electrode.

15. an external electrode located on a second surface opposite to the first surface; a through conductor penetrating the base, The wiring board according to claim 7 , wherein the through conductor connects the third portion and the external electrode.

16. A package comprising the wiring board according to claim 1 and a lid.

17. A piezoelectric device comprising the package according to claim 16 and a piezoelectric vibration element.

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