JP2015225963A - Wiring board, electronic device, and electronic module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring board which makes good electric connection between an inner surface electrode provided on an inner surface of a cutout part and a wiring conductor provided at an insulating substrate.SOLUTION: A wiring board 1 includes: an insulating substrate 11 having a cutout part 12 opening on a main surface and a side surface; an inner surface electrode 13 provided on an inner surface of the cutout part 12; and a wiring conductor 14 provided in the insulating substrate 11. The inner surface electrode 13 is divided into multiple parts in a thickness direction of the insulating substrate 11.

Description

  The present invention relates to a wiring board, an electronic device, and an electronic module.

  2. Description of the Related Art Conventionally, some wiring boards are provided with a wiring conductor inside or on the surface of the insulating base, a notch from the side surface to the bottom surface of the insulating base, and an inner surface electrode connected to the wiring conductor on the inner side surface. When an electronic device including an electronic component and a wiring board is bonded to, for example, a module substrate using a bonding material such as solder, the electrode is bonded to the module substrate via a bonding material such as solder.

JP 2002-158509 A

  In recent years, with the miniaturization of electronic devices and the high heat generation of electronic components, the distance from the mounting part of the electronic component to the notch has become closer, and the inner surface formed by the heat of the electronic component on the inner surface of the notch It is becoming more transmitted to the electrodes. With the increase in accuracy of wiring boards, it has been practiced to form wiring conductors etc. on the surface of an insulating substrate using a thin film method, but when an inner surface electrode is formed on the inner surface of a notch using a thin film method When an electronic component is operated, a stress due to a difference in thermal expansion between the insulating base and the inner surface electrode and a stress due to a difference in thermal expansion between the wiring board and the module substrate are applied to the upper part of the internal electrode via the bonding material. As a result, the inner surface electrode may be peeled off from the insulating substrate.

  According to one aspect of the present invention, the wiring board includes an insulating base having a notch opening in the main surface and the side surface, an inner surface electrode provided on the inner surface of the notch, A wiring conductor provided inside the insulating base, and the inner surface electrode is divided into a plurality of parts in the thickness direction of the insulating base.

  According to another aspect of the present invention, an electronic device includes the wiring board having the above configuration and an electronic component mounted on the wiring board.

  According to another aspect of the present invention, in the electronic module, the electronic device having the above configuration is connected to the connection pad of the module substrate via the bonding material.

  In the wiring board according to one aspect of the present invention, an insulating base having a notch opening in the main surface and side surfaces, an inner surface electrode provided on the inner side of the notch, and an inside of the insulating base Since the inner surface electrode is divided into a plurality of parts in the thickness direction of the insulating base, even if the heat of the electronic component is largely transferred to the inner surface electrode, the inner base and the inner surface are provided. The stress due to the difference in thermal expansion from the electrode and the stress due to the difference in thermal expansion between the wiring board and the module substrate are distributed to the plurality of inner surface electrodes, and the possibility that the inner surface electrode peels off from the insulating base can be reduced. Thus, a small and highly accurate wiring board having excellent electrical connection reliability with the module substrate can be obtained.

  An electronic device according to another aspect of the present invention is improved in terms of electrical reliability by including the wiring board having the above-described configuration and an electronic component mounted on the wiring board.

  In the electronic module according to another aspect of the present invention, since the electronic device having the above-described configuration is connected to the connection pad of the module substrate via a bonding material, the electrical connection reliability between the wiring substrate and the module substrate over a long period of time. It can be made excellent in properties.

(A) is a top view which shows the electronic device in the 1st Embodiment of this invention, (b) is a bottom view of (a). It is a side view in the A direction of Fig.1 (a). (A) is sectional drawing in the AA of the electronic device shown by Fig.1 (a), (b) is a principal part expanded sectional view in the A section of (a). It is a principal part expanded sectional view in the other example of the electronic device in the 1st Embodiment of this invention. (A), (b) is principal part expanded sectional drawing in the other example of the electronic device in the 1st Embodiment of this invention. (A)-(c) is sectional drawing which shows the 1st manufacturing method of the inner surface electrode, wiring conductor, and main surface electrode of the wiring board in the 1st Embodiment of this invention. (A)-(d) is sectional drawing which shows the 2nd manufacturing method of the inner surface electrode, wiring conductor, and main surface electrode of the wiring board in the 1st Embodiment of this invention. (A) is sectional drawing which shows the electronic module which mounted the electronic device in FIG. 1 on the board | substrate for modules, (b) is a principal part expanded sectional view in the A section of (a). (A) is a top view which shows the electronic device in the 2nd Embodiment of this invention, (b) is a bottom view of (a). It is a side view in the A direction of Fig.9 (a). (A) is sectional drawing in the AA of the electronic device shown by Fig.9 (a), (b) is a principal part expanded sectional view in the A section of (a). It is a principal part expanded sectional view which shows the other example of the electronic device in the 2nd Embodiment of this invention. (A) is a top view which shows the electronic device in the 3rd Embodiment of this invention, (b) is a bottom view of (a). It is a side view in the A direction of Fig.14 (a). (A) is sectional drawing in the AA of the electronic device shown by Fig.14 (a), (b) is a principal part expanded sectional view in the A section of (a). (A) is a top view which shows the electronic device in the 4th Embodiment of this invention, (b) is a bottom view of (a). (A) is sectional drawing in the AA of the electronic device shown by Fig.16 (a), (b) is a principal part expanded sectional view in the A section of (a). (A) is a top view which shows the electronic device in the 5th Embodiment of this invention, (b) is sectional drawing in the AA of (a). (A) is a top view which shows the electronic device in the 6th Embodiment of this invention, (b) is a bottom view of (a). FIG. 20 is a cross-sectional view taken along line AA of the electronic device shown in FIG. (A) is a bottom view which shows the electronic device in the 7th Embodiment of this invention, (b) is a side view in the A direction of (a). (A) is sectional drawing in the AA of the electronic device shown by Fig.21 (a), (b) is a principal part expanded sectional view in the A section of (a).

  Several exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

(First embodiment)
The electronic device according to the first embodiment of the present invention includes a wiring board 1 and an electronic component 2 provided on the upper surface of the wiring board 1, as shown in FIGS. Yes. As in the example shown in FIG. 8, the electronic device is connected to the module substrate 5 constituting the electronic module, for example, using the bonding material 6.

  The wiring substrate 1 includes an insulating base 11 having a cutout portion 12 opened on the main surface and side surfaces, an inner surface electrode 13 provided on the inner surface of the cutout portion 12, and an insulating base 11. Wiring conductors 14 are provided. The inner surface electrode 13 is divided into a plurality of parts in the thickness direction of the insulating base 11. 1 to 3 and 8, the electronic device is mounted on an xy plane in a virtual xyz space. 1 to 3 and 8, the upward direction and the thickness direction of the insulating base 11 refer to the positive direction of the imaginary z-axis.

  The insulating base 11 is composed of a plurality of insulating layers 11a, has an upper surface including a mounting area for the electronic component 2, and has a rectangular plate shape when viewed from a plan view, that is, a direction perpendicular to the main surface. Yes. The insulating base 11 functions as a support for supporting the electronic component 2, and the electronic component 2 is bonded and fixed to the mounting area in the center of the upper surface via a bonding member such as a low melting point brazing material or a conductive resin. The

  As the insulating substrate 11, for example, ceramics such as an aluminum oxide sintered body (alumina ceramic), an aluminum nitride sintered body, a mullite sintered body, or a glass ceramic sintered body can be used.

  If the insulating substrate 11 is made of, for example, an aluminum oxide sintered body, a suitable organic binder and solvent are added to and mixed with raw material powders such as aluminum oxide, silicon oxide, magnesium oxide and calcium oxide to form a slurry. Then, this is formed into a sheet shape by the doctor blade method or the calender roll method to obtain a ceramic green sheet. After that, the ceramic green sheet is subjected to appropriate punching processing, and a plurality of these are laminated to obtain a high temperature (about 1600 Manufactured by baking at a temperature of ° C.

  The notch 12 is opened on the main surface and side surface of the insulating base 11. The cutout portion 12 opens on the lower main surface (lower surface) and side surfaces of the insulating base 11 in FIGS. 1 to 3 and 8. The cutout portion 12 may be opened on the upper main surface (upper surface), lower main surface (lower surface), and side surfaces of the insulating substrate 11. The corners are formed in an arcuate rectangular shape in plan view, and are long along the outer side of the insulating substrate 11. In the example shown in FIGS. 1 to 3, the cutout portion 12 has a width (length along the side surface of the insulating base 11) in plan view that is the length of the cutout portion 12 (insulation). The length from the side surface of the base 11 to the bottom of the side wall of the notch 12) is formed. Note that the cutout portion 12 may have a semicircular shape, a semi-elliptical shape, a semi-oval shape, or a shape in which a plurality of cutout portions 12 overlap each other in plan view. Such cutouts 12 are formed by forming through holes to be the cutouts 12 in some of the ceramic green sheets for the insulating substrate 11 by laser machining or punching with a mold. The

  The inner surface electrode 13 is provided on the inner surface of the notch 12, and the wiring conductor 14 is provided on the surface and inside of the insulating base 11. In the example shown in FIGS. 1 to 3, a main surface electrode 15 connected to the inner surface electrode 13 is provided on the main surface where the notch 12 is open. Note that the structure includes the inner surface electrode 13 and the main surface electrode 15 to form an outer electrode. The wiring conductor 14 and the main surface electrode 15 are connected on the lower surface of the insulating base 11. The inner surface electrode 13 and the wiring conductor 14 are electrically connected via the main surface electrode 15.

  External electrodes including the inner surface electrode 13 and the main surface electrode 15 are for bonding to the module substrate 5. The inner surface electrode 13, the wiring conductor 14, and the main surface electrode 15 are for electrically connecting the electronic component 2 mounted on the wiring substrate 1 and the module substrate 5. The wiring conductor 14 includes a wiring conductor 14 provided on the surface or inside of the insulating base 11, and a through conductor that electrically connects the wiring conductors that are positioned above and below the insulating layer 11a constituting the insulating base 11. Is included.

The inner surface electrode 13 or the main surface electrode 15 is formed of a thin film layer, and includes, for example, an adhesion metal layer and a barrier layer. The adhesion metal layer constituting the inner surface electrode 13 or the main surface electrode 15 is formed on the main surface of the insulating base 11 and the inner surface of the notch 12. The adhesion metal layer is made of, for example, tantalum nitride, nickel-chromium, nickel-chromium-silicon, tungsten-silicon, molybdenum-silicon, tungsten, molybdenum, titanium, chrome, etc., and vapor deposition, ion plating, sputtering, etc. By adopting this thin film forming technique, the thin film is deposited on the surface of the insulating substrate 11 and the inner side surface of the notch 12. For example, in the case of forming using a vacuum vapor deposition method, the insulating substrate 11 is installed in a film forming chamber of a vacuum vapor deposition apparatus, a metal piece serving as an adhesion metal layer is disposed in a vapor deposition source in the film forming chamber, and then the formation is performed. By vacuuming the inside of the film chamber (pressure of 10 ⁻² Pa or less), heating and depositing a metal piece arranged in a deposition source, and depositing molecules of the deposited metal piece on the insulating substrate 11 Then, a thin film metal layer to be an adhesion metal layer is formed. Then, after a resist pattern is formed on the insulating substrate 11 on which the thin film metal layer is formed by using a photolithography method, an extra thin film metal layer is removed by etching to form an adhesion metal layer. A barrier layer is deposited on the top surface of the adhesion metal layer. The barrier layer has good adhesion and wettability between the adhesion metal layer and the plating layer, and firmly adheres the adhesion metal layer and the plating layer and also adheres to the adhesion metal layer and the plating layer. It acts to prevent interdiffusion with the layers. The barrier layer is made of, for example, nickel-chromium, platinum, palladium, nickel, cobalt or the like, and is deposited on the surface of the adhesion metal layer by a thin film forming technique such as a vapor deposition method, an ion plating method, or a sputtering method.

The thickness of the adhesion metal layer is preferably about 0.01 to 0.5 μm. If it is less than 0.01 μm, it tends to be difficult to firmly adhere the adhesion metal layer on the insulating substrate 11. When the thickness exceeds 0.5 μm, peeling of the adhesion metal layer is likely to occur due to internal stress during the formation of the adhesion metal layer. The thickness of the barrier layer is preferably about 0.05 to 1 μm. If it is less than 0.05 μm, defects such as pinholes tend to occur, making it difficult to function as a barrier layer. When the thickness exceeds 1 μm, the barrier layer is easily peeled off due to internal stress during film formation.

  The wiring conductor 14 can be made of a metal material such as tungsten (W), molybdenum (Mo), manganese (Mn), silver (Ag), or copper (Cu). For example, when the insulating substrate 11 is made of an aluminum oxide sintered body, a conductive paste obtained by adding and mixing a suitable organic binder and solvent to a refractory metal powder such as W, Mo or Mn is insulated. The ceramic green sheet to be the base 11 is preliminarily printed and applied in a predetermined pattern by a screen printing method, and is fired simultaneously with the ceramic green sheet to be the insulating base 11, thereby being deposited on a predetermined position of the insulating base 11. When the wiring conductor 14 is a through conductor, a through hole is formed in the green sheet by punching by a die or punching or laser processing, and a conductive paste for the wiring conductor 14 is filled into the through hole by a printing method. It is formed by placing.

  The inner surface electrode 13 is divided into a plurality of parts in the thickness direction of the insulating base 11. In the example shown in FIGS. 1 to 3, the inner surface electrode 13 is divided into two in the thickness direction of the insulating base 11. In the example shown in FIG. 2, the inner surface electrode 13 is shown by hatching. The fact that the inner surface electrode 13 is divided into a plurality of parts in the thickness direction of the insulating base 11 indicates that the inner surface electrode 13 is not continuous vertically on the inner surface of the cutout portion 12.

The wiring substrate 1 includes an insulating base 11 having a cutout portion 12 opened on the main surface and side surfaces, an inner surface electrode 13 provided on the inner surface of the cutout portion 12, and an insulating base 11. Since the inner surface electrode 13 is divided into a plurality of parts in the thickness direction of the insulating base 11, even if the heat of the electronic component 2 is largely transferred to the inner surface electrode 13, The stress due to the difference in thermal expansion between the insulating base 11 and the inner surface electrode 13 and the stress due to the difference in thermal expansion between the wiring board 1 and the module substrate 5 are distributed to the plurality of inner surface electrodes 13, and the inner surface electrode 13 peels from the insulating base 11. The possibility can be reduced, and the wiring substrate 1 can be made small and highly accurate with excellent electrical connection reliability with the module substrate 5 over a long period of time.

For example, when the inner surface electrode 13 is divided into two in the thickness direction of the insulating base 11, the distance h3 between the plurality of divided inner surface electrodes 13 is 0.05D1 ≦ h3 with respect to the depth D1 of the notch 12. If it is set to ≦ 0.3D1, a plurality of inner surface electrodes 13 can be formed with good division while ensuring a good area of the inner surface electrode 13 formed on the inner surface of the notch portion 12, so that the Thus, the wiring board 1 can be made small and highly accurate with excellent electrical connection reliability with the module substrate 5.

Further, for example, when the inner surface electrode 13 is divided into two in the thickness direction of the insulating base 11, the height h1 of the inner surface electrode 13 at the back bottom of the notch 12 and the inner side of the lower surface side opening of the notch 12 When the height h2 of the electrode 13 is set to about 0.28D1 ≦ h1 ≦ 0.57D1, 0.28D1 ≦ h2 ≦ 0.57D1, and 0.67h2 ≦ h1 ≦ 1.5h2, respectively, the difference in thermal expansion between the wiring substrate 1 and the module substrate 5 occurs. The stress is satisfactorily divided into the plurality of inner surface electrodes 13 along the thickness direction of the insulating base 11, and the possibility that the insulating base 11 and the inner surface electrode 13 are peeled can be reduced.

  In addition, the thickness of the inner surface electrode 13 at the bottom of the notch 12 may be smaller than the thickness of the inner electrode 13 at the lower surface side opening of the notch 12.

  Further, as in the example shown in FIG. 2, the stress due to the difference in thermal expansion between the wiring substrate 1 and the module substrate 5 is caused in the thickness direction of the insulating base 11 by being divided along the inner surface of the notch 12. Accordingly, the possibility that the insulating base 11 and the inner surface electrode 13 are peeled off can be reduced.

  In the example shown in FIGS. 1 to 3, the wiring conductor 14 and the main surface electrode 15 are connected to the main surface of the insulating base 11. In the example shown in FIG. 4, the inner surface electrode 13 and the wiring conductor 14 are connected at the end of the inner surface electrode 13 opposite to the main surface of the insulating base 11, that is, at the bottom of the notch 12. When the wiring conductor 14 is connected to the main surface electrode 15, compared with the case where the inner surface electrode 13 and the wiring conductor 14 are connected, the electrical connection between the electronic component 2, the wiring substrate 1, and the module substrate 5 is achieved. Connection can be made good.

  In the example shown in FIG. 5, each of the divided plurality of inner surface electrodes 13 is electrically connected to the wiring conductor 14. Since each of the plurality of inner surface electrodes 13 is electrically connected to the wiring conductor 14, even if one of the plurality of inner surface electrodes 13 is peeled off from the insulating base 11, the other inner surface electrode 13 is connected to the wiring conductor 14. As a result, the wiring board 1 is excellent in electrical connection reliability with the module substrate 5. In the example shown in FIG. 5A, each of the divided plurality of inner surface electrodes 13 is connected to the wiring conductor 14 on the inner surface of the cutout portion 12. In the example shown in FIG. 5B, one of the inner surface electrodes 13 and the wiring conductor 14 are connected at the bottom of the notch 12, and the wiring conductor 14 and the main surface electrode 15 are insulated. The lower main surface of the base 11 is connected.

  The wiring board 1 in the first embodiment of the present invention can be manufactured, for example, by the following manufacturing method.

In the first manufacturing method, as in the example shown in FIG. 6A, an insulating mother substrate 111 composed of a plurality of insulating layers 111a having a wiring conductor 14 formed on the inside and the surface is prepared. The insulating mother board 111 has a shape in which a plurality of insulating bases 11 are connected, for example, a shape of a wiring board for taking a plurality of pieces, and has a recess 112 that becomes a notch 12 that opens in the lower main surface. ing. Then, as in the example shown in FIG. 6B, the inner surface of the recess 112 that becomes the notch 12 of the insulating mother substrate 111 is divided into a plurality of portions in the thickness direction of the insulating mother substrate 111. The inner electrode 13 is formed. As shown in the example shown in FIG. 6C, the wiring substrate having the inner electrode 13 divided into a plurality in the thickness direction of the insulating substrate 11 on the inner surface of the notch 112 by dividing the recess 112. 1 can be made.

Next, the second manufacturing method will be described. In the second manufacturing method, as in the first manufacturing method, as in the example shown in FIG. 7A, an insulating layer 111a having a plurality of insulating layers 111a having wiring conductors 14 formed inside and on the surface is used. A mother board 111 is prepared. Then, as in the example shown in FIG. 7B, the inner electrode 13 is formed on the inner surface of the recess 112 that becomes the notch 12 of the insulating mother substrate 111. As in the example shown in FIG. 7C, the wiring board having the inner electrode 13 is manufactured on the inner surface of the notch 112 by dividing the recess 112. Further, as in the example shown in FIG. 7D, the inner electrode 13 formed on the inner surface of the notch 112 is divided into a plurality of parts in the thickness direction of the insulating substrate 11. A wiring substrate 1 having an inner electrode 13 divided into a plurality of portions in the thickness direction of the insulating substrate 11 can be manufactured on the inner surface of the substrate.

  Note that the first manufacturing method can produce the wiring substrate 1 with good productivity and good electrical connection between the electronic component 2, the wiring substrate 1, and the module substrate 5.

  In the second manufacturing method, when the size of the cutout portion 12 in a plan view is small, a plurality of divided inner surface electrodes 13 are accurately provided on the inner side surface of the cutout portion 12 in the thickness direction of the insulating base 11. Since it is easy to form, it is possible to manufacture the wiring board 1 with good electrical connection between the smaller electronic component 2 and the wiring board 1 and module board 5.

A plating layer is applied to the exposed surfaces of the electrode 13, the wiring conductor 14, and the main surface electrode 15 by an electrolytic plating method or an electroless plating method. The plating layer is made of a metal having excellent corrosion resistance such as nickel, copper, gold, or silver, and connectivity with the connection member. For example, the thickness is 0.5 to 5 μm.
A nickel plating layer of about 0.1 to 3 μm or a thickness of 1 to 10 μm
A nickel plating layer and a silver plating layer of about 0.1 to 1 μm are sequentially deposited. As a result, corrosion of the electrode 13, the wiring conductor 14, and the main surface electrode 15 can be effectively suppressed, and the wiring conductor 14 and the electronic component 2 can be fixedly bonded to each other or to the connection member 3 such as the wiring conductor 14 bonding wire. In addition, the bonding between the electrode 13 and the main surface electrode 15 and the connection pad 51 for connection formed on the module substrate 5 can be strengthened.

  Further, on the wiring conductor 14 on which the electronic component 2 is to be mounted, for example, a copper plating layer having a thickness of about 10 to 80 μm may be deposited so that the heat of the electronic component 2 can be easily radiated. Good. In addition, on the external electrode, for example, a copper plating layer having a thickness of about 10 to 80 μm may be deposited to easily dissipate the heat of the wiring board 1 satisfactorily.

An electronic device can be manufactured by mounting the electronic component 2 on the upper surface of the wiring board 1. The electronic component 2 mounted on the wiring board 1 is a semiconductor element such as an IC chip or an LSI chip, a light emitting element, a piezoelectric element such as a crystal vibrator or a piezoelectric vibrator, and various sensors. For example, when the electronic component 2 is a wire bonding type semiconductor element, the semiconductor element is fixed onto the wiring conductor 14 by a bonding member such as a low melting point brazing material or a conductive resin, and then bonded to a bonding wire or the like. The electrode of the semiconductor element and the wiring conductor 14 are electrically connected via the connecting member 3 to be mounted on the wiring board 1. For example, when the electronic component 2 is a flip-chip type semiconductor element, the semiconductor element is connected via a connecting member 3 such as a solder bump, a gold bump, or a conductive resin (anisotropic conductive resin, etc.) The electrode of the semiconductor element and the wiring conductor 14 are mounted on the wiring board 1 by being electrically and mechanically connected. In addition, a plurality of electronic components 2 may be mounted on the wiring board 1, or small electronic components such as a resistance element and a capacitive element may be mounted as necessary. Further, the electronic component 2 is sealed with a sealing material 4 made of resin, glass, or the like, a lid made of resin, glass, ceramics, metal, or the like, as necessary.

  As in the example shown in FIG. 8, the electronic device according to the present embodiment is connected to the connection pad 51 of the module substrate 5 via the bonding material 6 such as solder to form an electronic module. The bonding material 6 is bonded to the inner surface electrode 13 divided into a plurality of portions in the notch 12 and the main surface electrode 15 on the lower surface of the insulating base 11, so that the stress applied to the inner surface electrode 13 can be dispersed. It becomes possible. Further, the bonding material 6 is inclined so as to spread from the inner end of the notch 12 of the electrode 13 to the outer end of the connection pad 51. By adopting such a configuration, even if stress is generated in the electronic device due to an external force or the like during handling, the stress is dispersed by the bonding material 6 inclined so as to spread, and the electronic device becomes a module substrate. Thus, an electronic module with improved connection reliability can be obtained. In this case, when viewed in a plan view, that is, when viewed in a direction perpendicular to the main surface, the outer end portion of the connection pad 51 is located outside the end portion inside the cutout portion 12 of the inner surface electrode 13. Further, the inner end of the connection pad 51 is located at the same position as the inner end of the main surface electrode 15.

  According to the wiring board of the present embodiment, the insulating base 11 having the cutout portion 12 opened on the main surface and the side surface, the inner surface electrode 13 provided on the inner side surface of the cutout portion 12, and the insulating base. 13, and the inner surface electrode 13 is divided into a plurality of parts in the thickness direction of the insulating base 11, so that the heat of the electronic component 2 is greatly applied to the inner surface electrode 13. Even if transmitted, the stress due to the difference in thermal expansion between the insulating base 11 and the inner surface electrode 13 and the stress due to the difference in thermal expansion between the wiring board 1 and the module substrate 5 are distributed to the plurality of inner surface electrodes 13, and the inner surface electrode 13 is insulated. The possibility of peeling from the substrate 11 can be reduced, and the wiring board 1 can be made small and highly accurate with excellent electrical connection reliability with the module substrate 5 over a long period of time.

  The wiring board 1 in the present embodiment can be suitably used in a small and high-power electronic device, and electrical connection in the wiring board 1 can be favorably achieved. For example, the electronic component 2 can be suitably used as a small-sized wiring board 1 for mounting a light emitting element on which a high light emitting element is mounted.

  According to the electronic device of this embodiment, the electrical reliability is improved by having the wiring board 1 having the above-described configuration.

  According to the electronic module according to another aspect of the present invention, since the electronic device having the above configuration is connected to the connection pad 51 of the module substrate 5 via the bonding material 6, the wiring substrate 1 and the module are used for a long period of time. The electrical connection reliability with the substrate 5 can be excellent.

(Second Embodiment)
Next, an electronic device according to a second embodiment of the present invention will be described with reference to FIGS.

  The electronic device according to the second embodiment of the present invention is different from the electronic device according to the first embodiment described above in that the inner surface of the notch 12 is the same as the example shown in FIGS. A step 12a is provided, and the inner surface electrode 13 is divided into a plurality of steps by the step 12a.

According to the wiring board of the second embodiment of the present invention, the inner surface electrode 13 is formed on the inner side surface of the notch 12 in the thickness direction of the insulating base 11 so as to be well divided. Even if the inner side surface is displaced in the plane direction and the heat of the electronic component 2 is largely transferred to the inner surface electrode 13, the stress due to the thermal expansion difference between the insulating base 11 and the inner surface electrode 13 and the wiring board 1 and module The stress due to the difference in thermal expansion with respect to the substrate 5 is distributed to the plurality of inner surface electrodes 13, and the possibility that the inner surface electrode 13 is peeled off from the insulating base 11 can be reduced. Further, the inner surface electrode 13 is divided into a plurality of parts by the step 12a, and each of the inner surface electrodes 13 is spaced from each other in the plane direction, and the distance between the upper and lower inner surface electrodes 13 in the thickness direction of the insulating base 11, that is, FIG. 3 (b) to FIG. 5 (b) need not be provided, and the area of each inner surface electrode 13 can be made larger in the thickness direction of the insulating substrate 11, and the module can be used for a long time. A small and highly accurate wiring board 1 having excellent electrical connection reliability with the board 5 can be obtained.

In the second embodiment, as in the examples shown in FIGS. 9 to 11, the main surface side of the insulating base 11, that is, the lower surface side of the notch portion 12, from the back bottom side of the notch portion 12 in plan view. The step 12a is formed to be larger. With such a configuration, even if a stress that causes the electronic device to peel from the module substrate 5 is generated due to a difference in thermal expansion between the wiring substrate 1 and the module substrate 5, the stress can be dispersed by the step 12a. This is possible and preferable. The depth L of the step 12a is larger than the thickness of the inner surface electrode 13 on the back bottom side of the notch 12 and is formed to be about 30 μm to 200 μm. Such a wiring board 1 of the second embodiment can be manufactured using a manufacturing method similar to the first manufacturing method or the second manufacturing method described above. The step 12a may be formed by varying the size of the through hole for the cutout portion 12 formed in the green sheet to be the respective insulating layer 11a, or the green sheets to be the respective insulating layers 11a are laminated. At this time, lamination may be performed so that the lower surface side of the cutout portion 12 becomes smaller. In this way, the inner surface electrode 13 formed on the inner surface of the notch 12 can be divided into a plurality of portions in the thickness direction of the insulating base 11.

Further, as in the example shown in FIG. 12, the level difference 12a is formed so that the back bottom side of the notch 12 is larger than the main surface side of the insulating base 11, that is, the lower surface side of the notch 12 in plan view. When formed, the meniscus of the bonding material 6 for bonding the wiring substrate 1 and the module substrate 5 becomes gentle, and the bonding strength between the wiring substrate 1 and the module substrate 5 is further strengthened. Is possible and preferable. The depth L of the step 12a is larger than the thickness of the inner surface electrode 13 on the lower surface side of the notch 12, and is formed to be about 30 μm to 200 μm. Such a wiring board 1 of the second embodiment can be manufactured using a manufacturing method similar to the first manufacturing method or the second manufacturing method described above. The step 12a may be formed by varying the size of the through hole for the cutout portion 12 formed in the green sheet to be the respective insulating layer 11a, or the green sheets to be the respective insulating layers 11a are laminated. At this time, the layers may be laminated so that the lower surface side of the cutout portion 12 becomes larger. In this way, the inner surface electrode 13 formed on the inner surface of the notch 12 can be divided into a plurality of portions in the thickness direction of the insulating base 11.

  Further, since the wiring board 1 in the second embodiment is divided into a plurality of inner surface electrodes 13 by the step 12a as compared with the wiring board 1 in the first embodiment, the insulating substrate 11 is cut in the thickness direction. It is not necessary to provide a region for separating the plurality of inner surface electrodes 13 on the inner surface of the notch 12, so that the wiring board 1 can be easily thinned, and the plurality of inner electrodes 13 can be efficiently used on the inner surface of the notch 12. Easy to divide well.

For example, when the inner surface electrode 13 is divided into two in the thickness direction of the insulating base 11, in the second embodiment, the height h 1 of the inner surface electrode 13 at the bottom of the notch 12 and the notch 12. When the height h2 of the inner electrode 13 in the lower surface side opening is about 0.4D1 ≦ h1 ≦ 0.6D1, 0.4D1 ≦ h2 ≦ 0.6D1, 0.67h2 ≦ h1 ≦ 1.5h2, respectively, the wiring substrate 1 and the module substrate The stress due to the difference in thermal expansion with respect to 5 is well divided into a plurality of inner surface electrodes 13 along the thickness direction of the insulating base 11, and the possibility that the insulating base 11 and the inner surface electrodes 13 are peeled off can be reduced.

  Further, in the wiring board 1 according to the second embodiment, each of the divided plurality of inner surface electrodes 13 is connected to the wiring conductor 14 on the inner side surface of the notch 12 as in the example shown in FIG. As in the example shown in FIG. 5B, one of the inner surface electrodes 13 and the wiring conductor 14 are connected at the bottom of the notch 12, and the wiring conductor 14 is also connected. And the main surface electrode 15 may be connected on the lower surface side main surface of the insulating base 11.

  In the second embodiment, as in the example shown in FIGS. 9 to 12, the main surface electrode 15 is formed on the upper surface side and the lower surface side of the insulating substrate 11, and the upper surface side of the insulating substrate 11 and On the lower surface side, the wiring conductor 14 and the main surface electrode 15 are electrically connected to each other.

(Third embodiment)
Next, an electronic device according to a third embodiment of the present invention will be described with reference to FIGS.

  The electronic device according to the third embodiment of the present invention is different from the electronic device according to the first embodiment described above in that, as in the examples shown in FIGS. It is the point extended to the back bottom of 12.

  According to the wiring substrate 1 according to the third embodiment of the present invention, the inner surface electrode 13 is formed on the inner surface and the deep bottom surface of the notch 12, so that the module substrate 5 is interposed with the bonding material 6. When joining, the end portion of the inner surface electrode 13 is located not on the inner side surface of the notch portion 12 where the joining material 6 easily gets wet, but on the back bottom surface, and the wiring substrate 1 and the module substrate 5 are connected to each other. It is possible to make it difficult for the stress due to the difference in thermal expansion to be transmitted to the end of the inner surface electrode 13 through the bonding material 6, and it is small and highly accurate with excellent electrical connection reliability with the module substrate 5 over a long period of time. The wiring board can be made.

  The wiring board 1 of the third embodiment can be manufactured using a manufacturing method similar to the first manufacturing method or the second manufacturing method described above.

(Fourth embodiment)
Next, an electronic device according to a fourth embodiment of the present invention will be described with reference to FIGS.

  The electronic device according to the fourth embodiment of the present invention differs from the electronic device according to the first embodiment described above in that, as in the example shown in FIGS. 16 and 17, the wiring conductor 14 and the inner surface electrode 13. Alternatively, the connection portion with the main surface electrode 15 is formed large. Specifically, the inner surface electrode 13 is extended to the back bottom surface of the notch 12, the area where the wiring conductor 14 and the inner surface electrode 13 are connected is increased, and the through conductor constituting the wiring conductor 14 And a connecting land is provided between the inner surface electrode 13 and the main surface electrode 15 connected to the inner surface electrode 13, and the connected area is increased.

  According to the wiring board 1 according to the fourth embodiment of the present invention, the connection between the inner surface electrode 13 and the wiring conductor 14 or the connection between the wiring conductor 14 and the main surface electrode 15 is improved, and the insulating substrate 11 and the inner surface It is possible to reduce the possibility that the electrode 13 or the insulating base 11 and the main surface electrode 15 are peeled off, and to make a small and high-precision wiring board excellent in electrical connection reliability with the module substrate 5 over a long period of time. be able to.

  The wiring board 1 of the fourth embodiment can be manufactured using a manufacturing method similar to the first manufacturing method or the second manufacturing method described above.

  The wiring board 1 of the fourth embodiment can be formed, for example, by allowing the wiring conductor 14 to lead out over a wide range on the bottom surface of the notch 12 or the bottom surface of the insulating base 11. Further, if the lead is led out along the inner side surface of the notch 12 to the bottom surface of the notch 12, the inner electrode 13 and the wiring conductor 14 can be connected better, and the insulating base 11 and the inner electrode 13 The possibility of peeling off can be further reduced.

  Similarly, when the wiring conductor 14 and the main surface electrode 15 are connected to each other on the upper surface of the insulating base 11, a connection land between the through conductor and the main surface electrode 15 constituting the wiring conductor 14 is similarly formed. Just keep it.

  The insulating base 11 has an upper surface including the cavity 16 as in the example shown in FIGS. Such cavities 16 are formed in a plurality of ceramic green sheets through holes that become the cavities 16 by laser machining or punching with a mold on the ceramic green sheets, and these ceramic green sheets are formed through holes. It can be formed by laminating the ceramic green sheets. In addition, when the insulating substrate 11 is thin, it is preferable that the through hole for the cavity 16 is formed by laser processing, punching with a mold, or the like after laminating ceramic green sheets, because it can be processed with high accuracy. Further, as in the example shown in FIGS. 16 and 17, the notch 12 is about 25% to 75% of the width of the side wall of the cavity 16.

  When the cavity 16 is a space for mounting a light emitting element, the angle θ formed between the inner surface of the cavity 16 and the bottom surface of the cavity 16 is an obtuse angle, and may be 110 ° to 145 °. When the angle θ is in such a range, it is easy to stably and efficiently form the inner surface of the through-hole serving as the cavity 16 by punching, and the light emitting device using the wiring board 1 can be easily downsized. In addition, the light emitted from the light emitting element can be emitted well toward the outside. The cavity 16 having the inner surface with such an angle θ is formed by punching a ceramic green sheet using a punching die in which the clearance between the punch diameter and the die hole diameter is set large. In other words, by setting the clearance of the die hole diameter larger than the punch diameter of the punching die, the green sheet is punched when the ceramic green sheet is punched from the main surface side to the other main surface side. Is formed so that the diameter of the through hole spreads from the main surface side to the other main surface side by shearing from the edge of the contact surface to the edge of the contact surface with the die hole. At this time, the angle of the inner surface of the through hole formed in the ceramic green sheet can be adjusted by setting the clearance between the diameter of the punch and the diameter of the die hole according to the thickness of the ceramic green sheet. Such a punching method is highly productive because the angle θ formed by the inner surface of the cavity 16 and the bottom surface of the cavity 16 can be set to a desired angle only by punching.

  In addition, after forming a through hole having an angle θ of about 90 degrees by processing with a punching die having a small clearance between the diameter of the punch and the diameter of the die, a truncated cone shape or a truncated pyramid shape is formed on the inner surface of the through hole. A through-hole having an angle θ extending from one main surface side to the other main surface side as described above may be formed by pressing the mold. In such a case, the angle θ formed by the inner surface of the cavity 15 and the bottom surface of the cavity 15 can be adjusted with higher accuracy.

  When the wiring board 1 has an insulating base 11 having an upper surface including the cavity 16 on which the light emitting element is mounted, for example, a reflection layer for reflecting light emitted from the light emitting element is provided on the inner wall surface of the cavity 16. It may be done. The reflective layer has, for example, a metal conductor layer provided on the inner wall surface of the cavity 16 and a plating layer deposited on the metal conductor layer. The metal conductor layer can be formed by the same material and method as the electrode 13 and the main surface electrode 13a or the wiring conductor.

  For example, when a light emitting element is mounted on the wiring board 1, a silver plating layer is deposited on the outermost surface of the metal conductor layer, and a gold plating layer is formed on the outermost surface of the electrode 13, the main surface electrode 13a, and the wiring conductor 14. Is preferably applied. The gold plating layer is superior in bondability to the electronic component 2, the connection member 3, and the bonding material 6 as compared with the silver plating layer, and the silver plating layer has a light reflectivity as compared with the gold plating layer. This is because it is expensive. Further, the outermost surface of the wiring conductor 14 and the metal conductor layer in the portion where the light emitting element is mounted may be an alloy plating layer of silver and gold, for example, an alloy plating layer that is a solid solution of silver and gold.

  Similar to the first embodiment, the wiring board 1 of the fourth embodiment can be suitably used in a small and high-power electronic device, and electrical connection in the wiring board 1 can be favorably achieved. . For example, the electronic component 2 can be suitably used as a small wiring board for mounting a light emitting element on which a high light emitting element is mounted.

(Fifth embodiment)
Next, an electronic device according to a fifth embodiment of the present invention will be described with reference to FIG.

  The electronic device according to the fifth embodiment of the present invention differs from the electronic device according to the first embodiment described above in that the notch 12 is a mounting surface of the electronic component 2 as in the example shown in FIG. And the same main surface (hereinafter also referred to as the upper surface) and side surfaces.

  According to the wiring board of the fifth embodiment of the present invention, as in the wiring board of the first embodiment, the heat of the electronic component 2 is reduced from being transferred to the inner surface electrode 13 side, and the electronic component 2 Even if heat is transferred to the inner surface electrode 13, the stress due to the difference in thermal expansion between the insulating substrate 11 and the inner surface electrode 13 and the stress due to the difference in thermal expansion between the wiring substrate 1 and the module substrate 5 are distributed to the plurality of inner surface electrodes 13. Accordingly, the possibility that the inner surface electrode 13 is peeled off from the insulating base 11 can be reduced, and a small and highly accurate wiring board excellent in electrical connection reliability with the module substrate 5 can be obtained over a long period of time.

  The wiring substrate 1 of the fifth embodiment can be manufactured using a manufacturing method similar to the first manufacturing method or the second manufacturing method described above.

  In addition, since such a wiring board 1 can be bonded to the module substrate 5 with a bonding material 6 such as solder on the upper surface side of the wiring board 1, the thermal conductivity of the entire lower surface side of the wiring board 1 is higher than that of the insulating substrate 11. It is possible to improve the heat dissipation of the wiring board 1 by bonding a member having a high height. As a material having higher thermal conductivity than the insulating base 11, when the insulating base 11 is made of an aluminum oxide sintered body, a metal such as copper (Cu), copper-tungsten (Cu-W) or aluminum (Al) is used. Examples thereof include an insulator made of a material and an aluminum nitride sintered body. In such a wiring board 1, since the amount of heat transmitted from the electronic component 2 mounted on the wiring board 1 to the notch 12 side is suppressed, the stress applied to the inner surface electrode 13 can be more effectively reduced and extended for a long time. Thus, a wiring board excellent in electrical connection reliability and heat dissipation with the module substrate 5 can be obtained.

  Similar to the first embodiment, the wiring board 1 of the fifth embodiment can be suitably used in a small and high-power electronic device, and electrical connection in the wiring board 1 can be favorably achieved. . For example, the electronic component 2 can be suitably used as a small wiring board for mounting a light emitting element on which a high light emitting element is mounted.

  The wiring substrate 1 of the fifth embodiment can be manufactured using a manufacturing method similar to the first manufacturing method or the second manufacturing method described above.

(Sixth embodiment)
Next, an electronic device according to a sixth embodiment of the present invention will be described with reference to FIGS.

  The electronic device according to the sixth embodiment of the present invention is different from the electronic device according to the first embodiment described above in that, as in the example shown in FIG. 19 and FIG. 11 is open to both the main surface and the side surface.

  According to the wiring board according to the sixth embodiment of the present invention, as with the wiring board according to the first embodiment of the present invention, even if the heat of the electronic component 2 is largely transferred to the inner surface electrode 13, The stress due to the difference in thermal expansion with the inner surface electrode 13 and the stress due to the difference in thermal expansion between the wiring board 1 and the module substrate 5 are distributed to the plurality of inner surface electrodes 13, reducing the possibility that the inner surface electrode 13 is peeled off from the insulating substrate 11 Therefore, it is possible to provide a small and highly accurate wiring board having excellent electrical connection reliability with the module substrate 5 over a long period of time.

  In the sixth embodiment, as in the example shown in FIGS. 19 and 20, a recess 12a is formed between the plurality of inner surface electrodes 13, and the inner surface electrode 13 is located on the upper surface side of the insulating base 11. And the lower surface side.

  The recess-shaped step 12a is formed, for example, between the upper notch 12 where the inner surface electrode 13 is formed and the lower notch 12 with a larger diameter in plan view than these notches 12. It can be formed by interposing the notch 12. Such a wiring board 1 can be manufactured by forming the through holes for the notches 12 formed in the green sheets to be the respective insulating layers 11a with different sizes.

  The wiring board 1 of the sixth embodiment can be manufactured using a manufacturing method similar to the first manufacturing method or the second manufacturing method described above.

(Seventh embodiment)
Next, an electronic device according to a seventh embodiment of the present invention will be described with reference to FIGS.

  In the electronic device according to the seventh embodiment of the present invention, the difference from the electronic device according to the first embodiment described above is that, in the thickness direction of the insulating substrate 11, as in the example shown in FIGS. In the plan view, the width and length are different, and there is a step 12a. According to the wiring board according to the seventh embodiment of the present invention, as in the wiring board according to the first embodiment, even if the heat of the electronic component 2 is largely transferred to the inner surface electrode 13, the insulating substrate 11, the inner surface electrode 13, The stress due to the difference in thermal expansion and the stress due to the difference in thermal expansion between the wiring board 1 and the module substrate 5 are distributed to the plurality of inner surface electrodes 13, and the possibility that the inner surface electrode 13 is peeled off from the insulating substrate 11 can be reduced. Thus, it is possible to obtain a small and high-precision wiring board that has excellent electrical connection reliability with the module substrate 5 over a long period of time.

  The wiring substrate 1 according to the seventh embodiment can be manufactured by using a manufacturing method similar to the first manufacturing method or the second manufacturing method described above.

  Such a wiring board 1 can be manufactured by, for example, forming the through holes for the notches 12 formed in the green sheets to be the respective insulating layers 11a with different sizes and shapes. .

The present invention is not limited to the above-described embodiments, and various modifications can be made. In the above-described example, the notch portion 12 and the inner surface electrode 13 are respectively provided on the two opposing side surfaces of the insulating base 11, but the notch 12 and the inner surface electrode 13 are provided on the insulating base 11. The wiring board 1 provided on all four side surfaces or the wiring board 1 provided with a plurality of cutout portions 12 and the inner surface electrode 13 on each side may be used. In the example shown in FIGS. 1 to 22, the insulating base 11 is formed of three or three insulating layers 11a, but may be formed of two or four or more insulating layers 11a. I do not care.

  Further, the inner surface electrode 13 is divided into two on the upper surface side and the lower surface side of the wiring board 1, but it may be divided into three or more.

  Further, as in the example shown in FIG. 16, the wiring board 1 may have an electronic component mounting layer 17, a central terminal layer 18, and the like, which are conductors other than wiring. For example, these conductors can be manufactured by the same material and method as the above-described inner surface electrode 13, wiring conductor 14, and main surface electrode 15, and the exposed surface includes the inner surface electrode 13, wiring conductor 14, and main surface. A plating layer similar to that of the electrode 15 is applied. The electronic component mounting layer 17 is used, for example, for mounting the electronic component 2, and the central terminal layer 18 is used, for example, for bonding to the module substrate 5 similarly to the electrode 13 and the main surface electrode 13 a. Further, as in the example shown in FIG. 16, the central terminal layer 18 may also be connected to the inner surface electrode 13 provided on the inner surface of the cutout portion 12.

  Further, the wiring substrate 1 in the first to seventh embodiments may be a flat wiring substrate 1 or a wiring substrate 1 having a cavity 16. Moreover, in the wiring board 1 in the first to seventh embodiments, the cutout portion 12 may have a shape in which the cutout portions 12 having a plurality of sizes overlap as in the wiring board 1 in the second embodiment. Alternatively, the electronic component mounting layer 16 and the central terminal layer 17 may be provided.

  In the above example, one electronic component 2 is mounted on the wiring board 1, but it may be a wiring board 1 on which a plurality of electronic components 2 are mounted.

  Further, the wiring board 1 may be manufactured in the form of a multi-piece wiring board.

1 ... Wiring board
11 ... Insulating substrate
11a ... Insulating layer
12 .... Notch
13 ... Inner electrode
14 ... Wiring conductor
15 ... Main surface electrode
16 ... Cavity
17 ... Electronic component mounting layer
18 ... Central terminal layer 2 ... Electronic component 3 ... Connection member 4 ... Sealing material 5 ... Module substrate
51 ··· Connection pad 6 ··· Bonding material

Claims (4)

An insulating base having a notch opening in the main surface and side surfaces;
An inner surface electrode provided on the inner surface of the notch,
A wiring conductor provided inside the insulating base;
The wiring board according to claim 1, wherein the inner surface electrode is divided into a plurality of parts in the thickness direction of the insulating base. The inner surface of the notch has a step,
The wiring board according to claim 1, wherein the inner surface electrode is divided into a plurality of parts by the step. A wiring board according to claim 1;
An electronic device comprising: an electronic component mounted on the wiring board.   An electronic module according to claim 3, wherein the electronic device is connected to a connection pad of the module substrate via a bonding material.

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