JP2008091561A - Wiring substrate and electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic device capable of rigidly connecting electronic component to the end surface thereof and ensuring high reliability. <P>SOLUTION: When there is no region projected more than end electrodes 2a, 2b between end electrodes and the electronic component 5 is mounted on the end surface 11 of an insulating substrate 1, the electrode of electronic component 5 can be abutted against the end electrodes 2a, 2b of a wiring substrate. In the wiring substrate provided with the electrodes 2a, 2b for mounting the electronic component 5 on the end surface 11 of the insulating substrate 1, a plurality of electrodes 2a, 2b are provided on one end surface 11 while a recess 3 is provided between the electrode 2a and the electrode 2b. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wiring board and an electronic device for mounting electronic components.

  Conventionally, wiring boards for mounting electronic components such as semiconductor elements and crystal resonators are made of metal powder metallization such as tungsten or molybdenum on the surface of an insulating base made of an electrically insulating material such as an aluminum oxide sintered body. It is formed by arranging a wiring conductor made of The wiring board is formed as an electronic device by mounting electronic components on the top surface and sealing with a lid or potting resin.

  In recent years, it has been required to mount a large number of electronic components on a wiring board, and in addition, downsizing of electronic devices has been required. Therefore, in order to widen the mounting area of the electronic component on the wiring board, an electrode pad is formed on the side surface of the wiring board, and the electrode pad and the electrode of the electronic component are electrically connected by a conductive adhesive to A configuration in which an electronic component is mounted on the side surface has been proposed. Such a wiring board can be formed by laminating an upper layer and a lower layer each having a pair of electrode pads formed on the side surfaces on the upper surface and the lower surface of the intermediate layer (see Patent Document 1).

Japanese Patent Laid-Open No. 2001-111380

  However, since the wiring board described in Patent Document 1 is formed by laminating ceramics of an intermediate layer, an upper layer, and a lower layer, a misalignment may occur in each of the intermediate layer, the upper layer, and the lower layer. If the intermediate layer protrudes larger than the upper and lower side surfaces and misalignment occurs, the electronic component is mounted on the side surface of the intermediate layer, so the distance between the electrode pad formed on the upper and lower layers and the electronic component is large. The problem is that the bonding strength between the electronic component and the electrode pad to be bonded by the conductive adhesive varies, and in an extreme case, the electrode pad and the electronic component cannot be firmly bonded. Had.

  The present invention has been devised in view of the above-described problems of the prior art, and an object thereof is to provide a wiring board capable of firmly bonding an electronic component to an end face of an insulating substrate. Another object of the present invention is to provide a highly reliable electronic device.

  The wiring board of the present invention is a wiring board in which an end face electrode for mounting an electronic component is provided on an end face of an insulating board, wherein a plurality of the end face electrodes are provided on one end face, and the end face electrode and the end face electrode A recess is provided between them.

  Preferably, the wiring board is provided with a convex portion on a side opposite to the concave portion across the end face electrode.

  Preferably, a plurality of the recesses are arranged in the thickness direction so as not to overlap with each other in plan view.

  Preferably, the insulating substrate includes a plurality of insulating layers, and at least two insulating layers provided with the end face electrodes are laminated with an insulating layer not provided with the end face electrodes, and the end face electrodes are provided. The insulating layer that is not formed has a smaller outer shape than the insulating layer provided with the end face electrode.

  The electronic device of the present invention is characterized in that an electronic component is mounted on the end face of the wiring board of the present invention, and the electronic component is electrically connected to the end face electrode so as to straddle the recess. .

  The wiring board of the present invention is a wiring board in which an end face electrode for mounting an electronic component is provided on an end face of an insulating board, and a plurality of end face electrodes are provided on one end face, and between the end face electrode and the end face electrode. Since the concave portion is provided, the electrode of the electronic component and the end surface electrode of the wiring board are joined in a state where the concave portion is disposed between the end surface electrode and the end surface electrode. The area disappears, that is, the electrode protrudes from the end face of the insulating substrate located between the electrodes, and when the electronic component is mounted on the end face of the insulating substrate, the electrode of the electronic component is brought into contact with the end face electrode of the wiring board. It is possible to firmly bond the electronic component and the wiring board.

  Preferably, since the convex portion is provided on the opposite side of the concave portion across the end surface electrode, the convex portion can form a storage area for storing the electronic component on the end surface of the insulating substrate. Can be mounted on the end face of the insulating substrate with high accuracy, and the electrode of the electronic component and the end face electrode of the wiring board can be joined, and the electronic component and the wiring board can be firmly joined.

  Preferably, a plurality of recesses are arranged in the thickness direction and are provided so as not to overlap in a plan view. Therefore, when pressure is applied in the thickness direction of the insulating substrate, the pressure is favorably applied to the peripheral region of the recesses. Since it can be applied, it is possible to reduce poor adhesion and the like in the peripheral region of the recess, and it is possible to suppress the region located between the plurality of recesses from being compressed and deformed from the periphery. As a result, the shape of the recess can be made favorable, and the distance between the end face electrode and the end face electrode can be favorably formed to a predetermined dimension, so that the electronic component and the wiring board can be firmly bonded.

  Preferably, the insulating substrate includes a plurality of insulating layers, and at least two insulating layers provided with the end face electrodes are stacked with an insulating layer provided with no end face electrodes, and no end face electrodes are provided. Since the outer shape is smaller than the insulating layer provided with the end face electrode, when an insulating substrate is formed by stacking a plurality of insulating layers, the outer shape difference between the insulating layer provided with the end face electrode and the insulating layer provided with no end face electrode is Therefore, the recess can be formed between the end face electrode and the end face electrode with high accuracy and efficiency. Thereby, there is no region protruding from the end face electrode between the end face electrodes, and when the electronic component is mounted on the end face of the insulating substrate, the electrode of the electronic component can be brought into contact with the end face electrode of the wiring board. The wiring board can be firmly bonded.

  In the electronic device of the present invention, an electronic component is mounted on the end surface of the wiring board of the present invention, and the electronic component is electrically connected to the end surface electrode so as to straddle the concave portion. Since the end face electrode can be satisfactorily bonded, an electronic device having excellent reliability can be obtained.

  The wiring board of the present invention will be described. FIG. 1 is a plan view showing a wiring board according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line A-A 'of the wiring board in FIG. As shown in these drawings, the wiring board includes an insulating substrate 1, end surface electrodes 2a and 2b, a recess 3, and a wiring conductor 4, and an electronic component 5 can be mounted on the end surface.

  The wiring board of the present invention is provided with end face electrodes 2a and 2b for mounting the electronic component 5 on the end face 11 of the insulating substrate 1, and a plurality of end face electrodes 2a and 2b are provided on one end face 11, A recess 3 is provided between 2a and the end face electrode 2b.

The insulating substrate 1 is made of ceramics or the like. For example, when made of ceramics, the insulating substrate 1 is made of an electrical insulating material such as an aluminum oxide sintered body, a mullite sintered body, an aluminum nitride sintered body, or a silicon carbide sintered body. . When the insulating substrate 1 is made of an aluminum oxide sintered body, an organic solvent suitable for a raw material powder such as alumina (Al ₂ O ₃ ), silica (SiO ₂ ), calcia (CaO), magnesia (MgO), A solvent is added and mixed to make a mud-like shape, and a ceramic green sheet (ceramic green sheet) is obtained by forming the sheet into a sheet shape by using a conventionally known doctor blade method or calendar roll method. The sheet is manufactured by performing an appropriate punching process, stacking a plurality of sheets as necessary, and firing at a high temperature (about 1500 to 1800 ° C.).

  A plurality of end surface electrodes 2 a and 2 b are provided on the end surface 11 of the insulating substrate 1, which is a bonding region for bonding to the electrode of the electronic component 5 mounted on the end surface 11 of the insulating substrate 1, and the electronic component 5 is attached to the end surface 11. It functions as a conductive path for electrical connection to an external circuit board or the like, and is electrically connected to some of the wiring conductors 4 described later. The end surface electrodes 2a and 2b are made of metal powder metallization such as tungsten, molybdenum, copper, silver, and the like, and the end surface is formed at a predetermined position on the end surface 11 of the ceramic green sheet for the insulating substrate 1 by using printing means such as a screen printing method. The metallized paste for the electrodes 2 a and 2 b can be printed and applied, and simultaneously fired with the ceramic green sheet for the insulating substrate 1, so that it can be formed on the end surface 11 of the insulating substrate 1. The metallized paste is manufactured by adding an organic binder, an organic solvent, and a dispersant as necessary to a main component metal powder, and mixing and kneading them by a kneading means such as a ball mill, a three-roll mill, or a planetary mixer. Glass or ceramic powder may be added to match the sintering behavior of the ceramic green sheet or to increase the bonding strength with the insulating substrate after sintering.

  Further, through holes for the end face electrodes 2a and 2b are formed in the ceramic green sheet for the insulating substrate 1 by a die or punching method by punching or a processing method such as laser processing, and the through holes for the end face electrodes 2a and 2b are formed. The metallized paste for the end face electrodes 2a and 2b is filled by a printing means such as a screen printing method. The metallized paste for the end face electrodes 2a, 2b is divided in the thickness direction by cutting or the like so that the metallized paste for the end face electrodes 2a, 2b is exposed on the end face of the ceramic green sheet for the insulating substrate 1, and then insulated. The end face electrodes 2 a and 2 b may be formed on the end face 11 of the insulating substrate 1 by simultaneous firing with the ceramic green sheet for the substrate 1. In this case, the end surface electrodes 2a and 2b can be embedded in the insulating substrate 1, and the bonding strength between the insulating substrate 1 and the end surface electrodes 2a and 2b can be improved. When filling the through holes for the end face electrodes 2a and 2b, the metallized paste for the end face electrodes 2a and 2b is prepared to have a viscosity suitable for filling depending on the amount of the organic binder and the organic solvent.

  Note that the width (length in the width direction of the insulating substrate 1) and the length (length in the thickness direction of the insulating substrate 1) and the length (length in the thickness direction of the insulating substrate 1) of the end surface electrodes 2a and 2b are the same as the shape of the electronic component 5 bonded to the end surface electrodes 2a and 2b. What is necessary is just to select suitably collectively. Further, the end face electrode 2a and the end face electrode 2b, which are to be joined to the electronic component 5 to be described later, are paired with the recess 3 in between, and are preferably formed to have the same width and length. .

  A wiring conductor 4 is deposited on the insulating substrate 1. The wiring conductor 4 functions as a conductive path for electrically connecting the electronic component 5 and the second electronic component mounted on the wiring board to the external circuit board, and some of them are electrically connected to the end face electrodes 2a and 2b. It is connected to the. The wiring conductor 4 is made of metal powder metallization such as tungsten, molybdenum, copper, silver, and the like. The metallization for the wiring conductor 4 is formed at a predetermined position of the ceramic green sheet for the insulating substrate 1 by using a printing means such as a screen printing method. The paste can be printed and applied and simultaneously fired with the ceramic green sheet for the insulating substrate 1 to be formed at a predetermined position on the wiring board. The metallized paste for the wiring conductor 4 is produced in the same manner as the metallized paste for the end face electrodes 2a and 2b, but is prepared to have a viscosity suitable for printing depending on the amount of the organic binder or organic solvent.

  The wiring conductor 4 is also formed as a through conductor that penetrates the wiring board. Such a through conductor is formed by punching a ceramic green sheet for the insulating substrate 1 by a die or punching prior to printing and applying a metallized paste for forming the wiring conductor 4 formed on the upper surface, the lower surface, and the inside. A through hole for a through conductor is formed by a processing method such as a laser processing method, and a metallized paste is filled in the through hole for the through conductor by a printing means such as a screen printing method. It is formed by cofiring with a ceramic green sheet. The metallized paste for the through conductor is produced in the same manner as the metallized paste for the wiring conductor 4 formed on the end face electrodes 2a and 2b, the upper and lower surfaces, the inside, etc., but can be filled by the amount of organic binder or organic solvent. Prepared to a suitable viscosity.

  In addition, it is preferable to deposit a metal having excellent corrosion resistance, such as nickel or gold, on the exposed surfaces of the end face electrodes 2a and 2b and the wiring conductor 4. The end face electrodes 2a, 2b and the wiring conductor 4 are prevented from being oxidatively corroded, and the bonding between the electronic component 5 and the end face electrodes 2a, 2b or the wiring conductor 4 and the bonding between the wiring board and the external circuit board are strengthened. In order to achieve this, it is preferable that a nickel plating layer having a thickness of about 1 to 10 μm and a gold plating layer having a thickness of about 0.1 to 3 μm are sequentially deposited.

  And the recessed part 3 is provided between the end surface electrode 2a and the end surface electrode 2b. With this configuration, the electrode of the electronic component 5 and the end face electrodes 2a and 2b of the wiring board are joined in a state where the recess 3 is disposed between the end face electrode 2a and the end face electrode 2b. When the electronic component 5 is mounted on the end surface 11 of the insulating substrate 1, there is no region protruding from the end surface electrodes 2 a and 2 b, that is, the electrode protrudes from the end surface of the insulating substrate positioned between the electrodes. The electrode of the component 5 and the end face electrodes 2a and 2b of the wiring board can be brought into contact with each other, and the electronic component 5 and the wiring board can be firmly bonded.

  For example, when the insulating substrate 1 as shown in FIG. 2 is composed of three layers of insulating layers 1a, 1b, and 1c, the recess 3 has the outer shape of the insulating layer 1b in the peripheral region of the region where the end face electrodes 2a and 2b are formed. It can be formed if it is smaller than the outer shape of the insulating layers 1a and 1c. Note that reducing the outer shape herein means that the outer shape of the insulating layer 1b corresponding to the intermediate layer is made smaller than the outer shape of the insulating layers 1a and 1c on the end surface 11 side where the end surface electrodes 2a and 2b are formed. is there. For example, FIG. 3 shows an exploded plan view of each of the insulating layers 1a, 1b, and 1c in the wiring board of FIG. Insulating layers 1a, 1b, and 1c are formed by forming a notch 6 in the peripheral region of the insulating layer 1b that overlaps the end surface electrode 2a of the insulating layer 1a and the end surface electrode 2b of the insulating layer 1c when stacked. When the layers are stacked, the recess 3 can be formed between the end face electrode 2a and the end face electrode 2b of the end face 11 of the insulating substrate 1. That is, a ceramic green sheet for the insulating layers 1a, 1b, and 1c is prepared, and a mold or punching is preliminarily formed in a peripheral region of a region overlapping the region where the end face electrodes 2a and 2b of the ceramic green sheet for the insulating layer 1b are formed. The recess 3 is formed in a predetermined region of the insulating substrate 1 by forming the notch portion 6 by a punching method by laser processing or a processing method such as laser processing.

  Although it depends on the accuracy of the laminating apparatus and the material and thickness of the ceramic green sheets for the insulating layers 1a, 1b and 1c, in order to form the recesses 3 in the insulating substrate 1, a ceramic for the insulating layer 1b is required. The outer shape of the green sheet is 0.1 mm or more smaller in advance than the outer shape of the ceramic green sheet for the insulating layers 1a and 1c, that is, the length of the notch 6 (inward direction from the end surface of the ceramic green sheet for the insulating layer 1b) It is preferable to set the depth of cut into a depth of 0.1 mm or more. Further, the recess 3 is not limited to the notch 6 but may be a groove-like recess 3 formed in the width direction of the insulating substrate 1. Further, the insulating layer 1b is not limited to one layer. For example, as shown in a cross-sectional view of another embodiment shown in FIG. 4, the insulating layer has two or more intermediate layers (in FIG. 4, insulating layers 1b and 1b). , 1b ″, and the outer shape of the ceramic green sheet for these insulating layers 1b, 1b ′, 1b ″ is the insulating layer 1a, which forms the end face electrodes 2a, 2b, What is necessary is just to make it become smaller than the external shape of the ceramic green sheet for 1c beforehand.

  In addition, although the recessed part 3 can also be formed between the end surface electrode 2a and the end surface electrode 2b by performing cutting etc. to the end surface 11 of the insulating substrate 1, the thickness of the insulating substrate 1 is thin and the end surface electrode 2a and When the distance from the end face electrode 2b is small, it may be difficult to form the recess 3 accurately and efficiently between the end face electrode 2a and the end face electrode 2b by cutting or the like. The method by the lamination method in which the outer shape of the insulating layer 1b not provided with the end face electrodes 2a and 2b as described above is made smaller in advance than the outer shape of the insulating layers 1a and 1b provided with the end face electrodes 2a and 2b is accurate. The recess 3 can be formed between the end face electrode 2a and the end face electrode 2b efficiently, and this is preferable. When the electronic component 5 is mounted on the end face 11 of the insulating substrate 1, the electrode of the electronic component 5 and the end face of the wiring board are preferred. The electrodes 2a and 2b can be in good contact with each other, and the electronic component 5 and the wiring board can be firmly bonded. In particular, when a plurality of end surface electrodes 2a, 2b and a plurality of recesses 3 are formed on the end surface 11 of the insulating substrate 1, the recesses 3 are efficiently formed between the end surface electrodes 2a, 2b by this method. be able to.

  Note that the opening width of the recess 3 (the opening width in the direction orthogonal to the direction connecting the end surface electrodes 2a and 2b) is such that the electrode of the electronic component 5 is in good contact with the end surface electrodes 2a and 2b. It is formed wider than the width of the electronic component 5 mounted on the end surface 11 (the width in the direction orthogonal to the direction connecting the electrodes of the electronic component 5 connected to the end surface electrodes 2a and 2b). When the width of the end face electrodes 2a and 2b (the width in the direction perpendicular to the direction connecting the end face electrodes 2a and 2b) is wider than the width of the electronic component 5, the electronic component 5 is connected to the end face electrode 2a. , 2b, the opening width of the recess 3 is preferably formed wider than the width of the electrodes 2a, 2b. For example, when the width of the electronic component 5 is 0.3 mm and the width of the end surface electrodes 2 a and 2 b is 0.4 mm, the opening width of the recess 3 is at least twice the width of the electronic component 5. It is preferable to set it to 0.6 mm or more which is 1.5 times or more of the width of the electrodes 2a and 2b.

  Moreover, in order to mount the plurality of electronic components 5 on the end surface 11 of the insulating substrate 1, a plurality of end surface electrodes 2a and 2b may be formed in the thickness direction and the width direction of the end surface 11 of the insulating substrate 1, A small electronic device in which a plurality of electronic components 5 are mounted on the end surface 11 of the insulating substrate 1 can be obtained.

  Furthermore, as another embodiment of the present invention, the end surface 11 may be provided with a convex portion 7 on the opposite side of the thickness direction across the concave portion 3 from the end surface electrodes 2a and 2b. FIG. 5A is a cross-sectional view of a wiring board according to another embodiment, and FIG. 5B is a side view as viewed from the direction perpendicular to the end face 11, that is, from the direction of arrow D in FIG. FIG. In FIG. 5B, the electronic component 5 is not shown in order to make the structure of the end face 11 easy to understand.

  The convex portion 7 can form a storage area 8 for storing the electronic component 5 on the end surface 11 of the insulating substrate 1, and the electronic component 5 can be accurately mounted on the end surface 11 of the insulating substrate 1. The electronic component and the wiring board can be firmly bonded. For example, as shown in FIG. 5, when the insulating substrate 1 is composed of five insulating layers 1a to 1e, the outer surface of each of the insulating layers 1a and 1c is larger than the outer shape of the insulating layers 1a, 1b, and 1c. The insulating layers 1d and 1e may be stacked. That is, after the ceramic green sheets for the insulating layers 1d and 1e having a larger outer shape than the ceramic green sheets for the insulating layers 1a, 1b, and 1c are subjected to punching, printing of metallized paste for the wiring conductor 4, and the like. The insulating substrate 1 provided with the convex portions 7 can be formed by laminating the ceramic green sheets for the insulating layers 1a and 1c on the respective main surfaces and firing them. In addition, in the point which forms the convex part 7 in the insulated substrate 1 accurately and efficiently, the means by the above-mentioned lamination method is preferable, However, You may form the convex part 7 by the other method. For example, by applying printing means such as a screen printing method, a ceramic paste for the convex portion 7 is printed and applied to a region opposite to the concave portion 3 of the electrodes 2a and 2b on the end faces of the ceramic green sheets for the insulating layers 1d and 1e. The ceramic paste may be applied to a predetermined region by firing together with the ceramic green sheet for the insulating substrate 1.

  Such a ceramic paste for the convex portion 7 is mixed and mixed by kneading means such as a ball mill, a three-roll mill, a planetary mixer, etc. by adding an organic binder, an organic solvent, and a dispersant as required to the ceramic powder of the main component. Produced by kneading.

  In addition, since the convex part 7 is formed by firing together with the insulating substrate 1, it is preferable that the convex part 7 is made of substantially the same component as the insulating substrate 1. That is, when the insulating substrate 1 is made of an aluminum oxide sintered body, the convex portion 7 is made of an aluminum oxide sintered body, and when the insulating substrate 1 is made of an aluminum nitride sintered body, the convex portion 7 is nitrided. It is preferably made of an aluminum sintered body.

  Further, the height of the convex portion 7 (the length of the portion protruding outward from the electrodes 2a and 2b) is the height of the electronic component 5 (the length of the electrodes 2a and 2b of the electronic component 5 mounted on the electrodes 2a and 2b). It is preferable that the height is higher than the height from the surface to the outside. Thereby, the electronic component 5 can be securely stored in the storage area 8 and the possibility that the electronic component 5 protrudes from the end surface 11 of the insulating substrate 1 can be reduced. Therefore, when transporting the wiring board and the electronic device, It is possible to reduce the possibility that the electronic component 5 mounted on the end surface 11 of the insulating substrate 1 comes into contact with the conveyance path or the like of the conveyance device, and it is possible to reduce the possibility that the electronic component 5 is chipped. In addition, what is necessary is just to form such a convex part 7 by setting the length of the convex part 7 so that it may become higher than the height of the electronic component 5 accommodated in the storage area | region 8. FIG.

  Moreover, the convex part 7 may be provided so that the end surface electrodes 2a and 2b and the concave part 3 may be surrounded, and may be formed as the storage area | region 8 which accommodates the electronic component 5 over a perimeter. That is, the convex portion 7 may be formed in the thickness direction and the width direction of the insulating substrate 1 so as to surround the concave portion 3 and the end surface electrodes 2a and 2b.

  Moreover, as shown in the side view of FIG. 6, a plurality of the recesses 3 are preferably arranged in the thickness direction of the insulating substrate 1 so as not to overlap each other in plan view. In addition, when it does not overlap in planar view here, the some recessed part 3 overlaps when the several recessed part 3 provided in the end surface 11 of the insulating base | substrate 1 is seen through from a plane direction (upward direction in FIG. 6). Say nothing. In FIG. 6, a plurality of electrodes 2a to 2h are formed on the same end surface 11 of the insulating substrate 1, between the electrodes 2a and 2b, between the electrodes 2c and 2d, and between the electrodes 2e and 2f. Are formed between the electrode 2g and the electrode 2h. The electrode 2a and the electrode 2b, the electrode 2c and the electrode 2d, the electrode 2e and the electrode 2f, and the electrode 2g and the electrode 2h, respectively. An electronic component 5 (not shown) is mounted. Accordingly, when a pressure is applied in the thickness direction, such as when the ceramic green sheets for the insulating layers 1a to 1h are laminated, the plurality of recesses 3 do not overlap in the direction in which the pressure is applied. A pressure can be favorably applied to the region. That is, a region where the pressure is difficult to be applied is generated in the peripheral region of the recess 3 due to a difference in the shape of the recess 3 or a stacking deviation of the recess 3, and adhesion failure occurs between the layers of the ceramic green sheets for the insulating layers 1a to 1h. Since the possibility can be reduced, the pressure can be favorably applied to the peripheral region of the recess 3. Moreover, it can suppress that the deformation | transformation of the some recessed part 3 generate | occur | produces because the insulating layer located between the some recessed part 3 is compressed from a periphery and deform | transforms. Thereby, it becomes easy to form the shape of the plurality of recesses 3 in a predetermined shape favorably, the distance between the electrode 2a and the electrode 2b can be improved in a predetermined dimension, and the electronic component and the wiring board can be strengthened. Can be joined. In the case where a plurality of storage areas 8 are formed on the end surface 11 of the insulating substrate 1, similarly, in order to suppress deformation of the storage areas 8, it is preferable that they are provided so as not to overlap in plan view.

  In the electronic device of the present invention, the electronic component 5 is mounted on the end surface 11 of the wiring board of the present invention, and the electronic component 5 is connected to the electrodes 2 a and 2 b so as to straddle the recess 3. Thereby, since the electrode of the electronic component 5 and the electrodes 2a and 2b of the wiring board can be satisfactorily bonded, an electronic device having excellent reliability can be obtained.

  The electronic component 5 is a chip element such as a capacitor, a resistance element, or an inductor. The electronic component 5 is mounted by electrically connecting the electrode of the chip element and the electrodes 2a and 2b of the wiring board via a conductive adhesive such as solder. Moreover, the electronic component 5 is sealed as needed. Sealing is performed by covering the electronic component 5 with a sealing resin such as epoxy resin, or a lid made of resin, metal, ceramics, etc. placed so as to cover the electronic component 5 is made of glass, resin, brazing material, etc. It may be performed by attaching to the laminated substrate with an adhesive. When the housing region 8 is formed, both sealing with a resin and sealing with a lid can be efficiently performed.

  In addition, the electronic component 5 and the second electronic component are mounted on one main surface or the other main surface of the wiring board. The second electronic component is a semiconductor element such as an IC (Integrated Circuit) chip or an LSI (Large Scale Integration) chip, a piezoelectric element such as a crystal vibrator or a piezoelectric vibrator, or various sensors. When the second electronic component is a flip-chip type semiconductor element, the second electronic component is mounted on the semiconductor via a solder bump, a gold bump, or a conductive resin (anisotropic conductive resin or the like). It is performed by electrically connecting the electrode of the element and the wiring conductor 4, and when the second electronic component is a wire bonding type semiconductor element, it is made of a bonding material such as glass, resin, or brazing material. After fixing the semiconductor element on the surface of the wiring board, the electrodes of the semiconductor element and the wiring conductor 4 are electrically connected through bonding wires. When the second electronic component is a piezoelectric element such as a crystal resonator, the piezoelectric element is fixed and the electrode of the piezoelectric element and the wiring conductor 4 are electrically connected by a conductive resin. And a 2nd electronic component is sealed by the same means as the above-mentioned electronic component as needed.

  The present invention can be variously modified without departing from the gist of the present invention. For example, as shown in the cross-sectional view of FIG. 7, a storage area (cavity) 9 for storing a second electronic component other than the first electronic component 5 is formed on one main surface or the other main surface of the insulating substrate 1. It may be provided. In addition, the electrodes 2 a and 2 b and the recesses 3 may be provided not only on one end face of the insulating substrate 1 but also on a plurality of end faces of the insulating substrate 1. With this configuration, the electronic component 5 can be mounted on each of the electrodes 2a and 2b formed on the respective end surfaces, and therefore more electronic components 5 can be mounted using the end surface of the insulating substrate 1 effectively. In addition, a small and highly reliable electronic device can be formed. For example, when the planar view shape of the insulating substrate 1 is rectangular, the electrodes 2a, 2b and the recess 3 may be formed on each of the four end surfaces.

It is a top view which shows the wiring board which is embodiment of this invention. FIG. 2 is a cross-sectional view taken along line A-A ′ of the wiring board in FIG. 1. FIG. 3 is an exploded plan view of each of insulating layers 1a, 1b, and 1c in the wiring board shown in FIG. It is sectional drawing which shows the wiring board which is other embodiment of this invention. (A) It is sectional drawing which shows the wiring board which is other embodiment of this invention, (b) It is the side view seen from the direction perpendicular | vertical to the end surface 11. FIG. It is a side view which shows the wiring board which is other embodiment of this invention. It is sectional drawing which shows the wiring board which is other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Insulating substrate 1a-1h Insulating layer 2a-2h End surface electrode 3 Concave part 4 Wiring conductor 5 Electronic component 6 Notch part 7 Convex part 8,9 Storage area

Claims (5)

  In a wiring board in which an end face electrode for mounting an electronic component is provided on an end face of an insulating substrate, a plurality of the end face electrodes are provided on one end face, and a recess is provided between the end face electrode and the end face electrode. A wiring board characterized by that.   The wiring board according to claim 1, wherein a convex portion is provided on a side opposite to the concave portion across the end face electrode.   The wiring board according to claim 1, wherein a plurality of the recesses are arranged in a thickness direction so as not to overlap each other in a plan view. The insulating substrate includes a plurality of insulating layers;
The at least two insulating layers provided with the end face electrodes are laminated with an insulating layer not provided with the end face electrodes, and the insulating layer not provided with the end face electrodes is more than the insulating layer provided with the end face electrodes. 3. The wiring board according to claim 1, wherein the outer shape is small.   An electronic component is mounted on an end face of the wiring board according to claim 1, and the electronic component is electrically connected to the end face electrode so as to straddle the concave portion. Electronic equipment.

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