JP6224473B2 - Wiring board, electronic device and electronic module - Google Patents

Description

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

  2. Description of the Related Art Conventionally, a wiring conductor is provided inside or on the surface of an insulating substrate, and a cutout portion is provided from the side surface to the lower surface of the insulating substrate and an inner surface electrode connected to the wiring conductor is provided on the inner surface thereof. When an electronic device including a wiring board is bonded to, for example, an external circuit board using a bonding material such as solder, the inner surface electrode is bonded to the external circuit board via a bonding material such as solder.

JP 2002-158509 A

  In recent years, with the miniaturization of wiring boards, the miniaturization and thinning of wiring conductors and inner surface electrodes have progressed. In such a wiring board, if a large current is applied from the external circuit board to the inner surface electrode, the current path from the outer circuit board containing the bonding material such as solder to the wiring board is reduced during operation of the electronic device, and the inner surface electrode Since the current path is the smallest in the vicinity of the connection portion between the wiring conductor and the wiring conductor, current concentration occurs, and there is a possibility that the connection portion between the inner surface electrode and the wiring conductor may be disconnected or abnormal in resistance. If the electronic component is a light emitting element, there is a concern that it may not emit light normally.

According to one aspect of the present invention, a wiring board includes an insulating base having a main surface and a side surface, a first inner surface extending inward from the side surface of the insulating base, and an inner side from the main surface and side surface of the insulating base. a notch portion including a second inner surface which extends, the inner surface electrode provided on the second inner surface of the cutout portion, is connected to the inner surface electrode before Symbol notch, the first An extending electrode extending in a band shape from the second inner surface to the inside of the notch portion on the inner surface of the first inner surface; and the extension electrode provided inside the insulating base and extending in the back of the notch portion. Wiring conductor connected to electrode
The wiring conductor is thicker at the connection portion with the inner surface electrode .

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

In a wiring board according to one aspect of the present invention, an insulating base having a main surface and side surfaces, a first inner surface extending inward from the side surfaces of the insulating base, and a second extending inward from the main surfaces and side surfaces of the insulating base. of and the notches including an inner surface, an inner surface electrode provided on the second inner surface of the cutout portion, is connected to the inner surface electrode of the switching Operation-out portion, on a first inner surface, a second inner surface An extending electrode extending in a strip shape from the inside of the notch to the inside of the notch, and a wiring conductor provided inside the insulating base and connected to the extending electrode at the back of the notch Since the conductor is thick at the connection with the inner surface electrode, even if a large current is applied from the external circuit board to the wiring board, the current from the external circuit board containing the bonding material such as solder to the wiring board The path is near the connection between the inner electrode and the wiring conductor Therefore, current concentration in the vicinity of the connection portion between the inner surface electrode and the wiring conductor is suppressed, and the connection portion between the inner surface electrode and the wiring conductor is prevented from being broken or abnormal in resistance. The electrical connection reliability can be improved. When the electronic component is a light-emitting element, a wiring board that can emit light satisfactorily can be obtained.

  An electronic device according to another aspect of the present invention is improved in terms of electrical reliability and electrical characteristics by including the wiring board having the above configuration. When the electronic component is a light-emitting element, a light-emitting device that can emit light well over a long period of time can be obtained.

(A) is a top view which shows the electronic device in the 1st 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.1 (a). (A) is a principal part expanded bottom view in the A section of the electronic device shown by FIG.1 (b), (b) is sectional drawing in the AA of (a). (A), (b) is the principal part enlarged bottom view in the other example of the electronic device in the 1st Embodiment of this invention. (A)-(d) is sectional drawing which shows the 1st manufacturing method of the inner surface electrode, wiring conductor, and extension 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 extension 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). (A) is sectional drawing in the AA of the electronic device shown by Fig.8 (a). (A) is the principal part enlarged bottom view in the A section of the electronic device shown by FIG.8 (b), (b) is sectional drawing in the AA 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)-(d) is sectional drawing which shows the 3rd manufacturing method of the inner surface electrode, wiring conductor, and extension electrode of the wiring board in the 2nd Embodiment of this invention. (A) is a top view which shows the other example of the electronic device in the 2nd Embodiment of this invention, (b) is a bottom view of (a). (A) is a top view which shows the other example of the electronic device in the 3rd Embodiment of this invention, (b) is sectional drawing in the AA of (a).

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

(First embodiment)
As shown in FIGS. 1, 2, and 7, 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. Yes. As in the example shown in FIG. 7, the electronic device is connected to the external circuit substrate 5 (for example, 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 main surface and side surfaces, a first inner surface 12a extending inward from the side surfaces of the insulating base 11, and a second inner surface extending inward from the main surfaces and side surfaces of the insulating base 11. A notch portion 12 including 12b, an inner surface electrode 13 provided on the second inner surface 12b of the notch portion 12, and an inner surface electrode 13 of the notch portion 12, and on the first inner surface 12a. The extension electrode 15 extending in a band shape from the second inner surface 12b to the inside of the notch 12 and the insulating base 11 are provided inside and connected to the extension electrode 15 at the back of the notch 12. Wiring conductor 14. 1, 2, and 7, the electronic device is mounted on an xy plane in a virtual xyz space. 1, 2, and 7, the upward direction refers to the positive direction of the virtual 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 in plan view. 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 cutout portion 12 is provided on the side surface of the insulating base 11, and includes a first inner surface 12a and a second inner surface 12b. The first inner surface 12 a is formed to extend inward from the side surface of the insulating base 11, and the second inner surface 12 b is formed to extend inward from the main surface and the side surface of the insulating base 11. That is, the notch 12 is formed to open on one main surface and side surface of the insulating base 11, and in the example shown in FIGS. 1 to 4, it is formed to open on the bottom surface and side of the insulating base 11. ing. In the example shown in FIGS. 1 to 4, the notch 12 is formed in a rectangular shape with a corner having an arc shape in plan view, and is formed long along the outer side of the insulating base 11. 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 second inner surface 12 b 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 4, a main surface electrode 13 a connected to the inner surface electrode 13 is provided on the main surface where the notch 12 is open. In addition, it is an external electrode by the structure containing the inner surface electrode 13 and the main surface electrode 13a. The inner surface electrode 13 and the wiring conductor 14 are connected at the back of the notch 12. The inner surface electrode 13 may be extended by about 0.05 to 0.1 mm so as to surround the notch portion 12 in a plan view at the connection portion with the wiring conductor 14. The external electrodes including the inner surface electrode 13 and the main surface electrode 13 a are for bonding to the external circuit board 5. The inner surface electrode 13, the main surface electrode 13a, and the wiring conductor 14 are for electrically connecting the electronic component 2 mounted on the wiring board 1 and the external circuit board 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 extension electrode 15 is connected to the inner surface electrode 13 and extends on the first inner surface 12 a of the notch 12 from the inner surface electrode 13 to the inside of the notch 12 in a strip shape. The extension electrode 15 is for joining the external circuit board 5 and electrically connecting the electronic component 2 mounted on the wiring board 1 and the external circuit board 5 in the same manner as the inner surface electrode 13. The extension electrode 15 extends from the inner surface electrode 13 on the first inner surface 12a of the cutout portion 12 to the inside of the cutout portion 12 in a band shape by about 0.05 to 0.2 mm.

  The inner surface electrode 13, the main surface electrode 13a, the wiring conductor 14, and the extension electrode 15 are made of a metal material such as tungsten (W), molybdenum (Mo), manganese (Mn), silver (Ag), or copper (Cu). Can do. 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 formed by printing and applying a conductive paste for the inner surface electrode 13 in a region which is an inner surface of the through hole that becomes the notch 12. The main surface electrode 13a is formed by printing and applying a conductor paste to be the main surface electrode 13a to the ceramic green sheet to be the insulating base 11. The extension electrode 15 is formed by printing and applying a conductor paste that becomes the extension electrode 15 in a region that becomes the end portion on the other main surface side of the cutout portion 12.

  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. 5A, the ceramic green sheets 111 and 211 to be the insulating base 11 are formed on the through hole 112 for the wiring conductor 14 and the through hole for the notch 12. A hole 212 is formed. Then, as in the example shown in FIG. 5B, the conductor paste 113 for the inner surface electrode 13 is applied and printed on the inner surface of the through-hole 212 that becomes the notch 12 of the ceramic green sheet 211 by screen printing. . Further, the conductor paste 113a for the main surface electrode 13a is applied and printed on the surface of the ceramic green sheet 211 by a screen printing method. Further, the conductor paste 114 for the wiring conductor 14 and the conductor paste 115 for the extension electrode 15 are applied and printed on the surface of the ceramic green sheet 111 and the through hole 112 for the wiring conductor 14 by screen printing. Here, the conductor paste 114 for the wiring conductor 14 and the conductor paste 115 for the extension electrode 15 are formed to be connected. Then, by laminating and pressing the ceramic green sheets 111 and 211, the conductor paste 114 for the wiring conductor 14 and the conductor paste 115 for the extension electrode 15 are connected, and the conductor paste for the inner surface electrode 13 As shown in FIG. 5C, a ceramic green laminate is formed as an insulating base 11 to which 113 and a conductor paste 114 for the wiring conductor 14 are connected, and this ceramic green laminate is fired. Then, the insulating base 11 having the recess 312 having the inner surface electrode 13 and the extension electrode 15 is formed on the inner surface that becomes the cutout portion 12. Further, as in the example shown in FIG. 5 (d), the inner surface electrode 13 provided on the second inner surface 12 b of the notch 12 and the inner surface of the notch 12 are separated by dividing the recess 312. A wiring substrate 1 having an extension electrode 15 connected to the electrode 13 and provided on the first inner surface 12a of the notch 12 can be manufactured.

  Next, the second manufacturing method will be described. Similar to the first manufacturing method, in the second manufacturing method, as in the example shown in FIG. 6A, the ceramic green sheets 111 and 211 serving as the insulating base 11 are formed in the through holes for the wiring conductor 14. 112 and a through hole 212 for the notch 12 are formed. Then, as in the example shown in FIG. 6B, the conductor paste 113 for the inner surface electrode 13 is applied and printed on the inner surface of the through-hole 212 serving as the cutout portion 12 of the ceramic green sheet 211 by screen printing. At the same time, the conductor paste 113 for the main surface electrode 13a and the conductor paste 114 for the wiring conductor 14 are applied and printed on the surface of the ceramic green sheet 211 by screen printing. Here, the conductor paste 113 for the inner surface electrode 13 and the conductor paste 114 for the wiring conductor 14 are formed to be connected. Further, the conductor paste 114 for the wiring conductor 14 and the conductor paste 115 for the extension electrode 15 are applied and printed on the surface of the ceramic green sheet 111 and the through hole 112 for the wiring conductor 14 by screen printing. Then, by laminating and pressing the ceramic green sheets 111 and 211, the conductor paste 114 for the wiring conductor 14 and the conductor paste 115 for the extension electrode 15 are connected, and the conductor paste for the inner surface electrode 13 As shown in FIG. 6C, a ceramic green laminate is formed as an insulating base 11 to which 113 and the conductor paste 114 for the wiring conductor 14 are connected, and this ceramic green laminate is fired. Then, the insulating base 11 having the recess 312 having the inner surface electrode 13 and the extension electrode 15 is formed on the inner surface that becomes the cutout portion 12. Further, as in the example shown in FIG. 6D, the inner surface electrode 13 provided on the second inner surface 12 b of the notch 12 and the inner surface of the notch 12 are separated by dividing the recess 312. A wiring substrate 1 having an extension electrode 15 connected to the electrode 13 and provided on the first inner surface 12a of the notch 12 can be manufactured.

  The first manufacturing method has better connection between the inner surface electrode 13 and the wiring conductor 14 and the connection between the wiring conductor 14 and the extension electrode 15 than the second manufacturing method. It is easy to form an electrical connection between the wiring conductor 14 and the extension electrode 15 as a good wiring substrate 1, and it can be used more suitably in a small and high-power electronic device. The second manufacturing method is easy to use in the wiring board 1 where the thickness of the insulating layer 11a and the insulating base 11 is thin because it is easy to reduce deformation during lamination.

  A plating layer is applied to the exposed surfaces of the inner surface electrode 13, the main surface electrode 13a, the wiring conductor 14, and the extension 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 a connection member. For example, a nickel plating layer having a thickness of about 0.5 to 5 μm and a gold plating having a thickness of about 0.1 to 3 μm A nickel plating layer having a thickness of about 1 to 10 μm and a silver plating layer having a thickness of about 0.1 to 1 μm are sequentially deposited. As a result, corrosion of the inner surface electrode 13 and the main surface electrode 13a, the wiring conductor 14, and the extension electrode 15 can be effectively suppressed, the wiring conductor 14 and the electronic component 2 can be fixedly adhered, the wiring conductor 14 and the bonding wire, etc. The connection member 3 and the inner surface electrode 13, the main surface electrode 13a, the extension electrode 15, and the connection pad 51 for connection formed on the external circuit board 5 (module substrate 5) can be strengthened. . Further, on the wiring conductor 14 on which the electronic component 2 is to be mounted, a copper plating layer having a thickness of about 10 to 80 μm is deposited on the nickel plating layer, so that the heat of the electronic component 2 can be dissipated well. It may be easier.

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 on the wiring conductor 14 by a bonding member such as a low melting point brazing material or a conductive resin, and then connected to a bonding wire or the like. The electrode of the semiconductor element and the wiring conductor 14 are electrically connected via the 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 13 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. 7, 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, the extended electrode 15, and the main surface electrode 13 a in the notch 12. The bonding material 6 is inclined so as to spread from the inner end of the cutout portion 12 of the extended electrode 15 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 seen in a plan view, the outer end portion of the connection pad 51 is located outside the end portion inside the cutout portion 12 of the extended electrode 15. Further, the inner end of the connection pad 51 is located at the same position as the inner end of the main surface electrode 13a.

  According to the wiring substrate 1 of the present embodiment, the insulating base 11 having a main surface and side surfaces, the first inner surface 12a extending inward from the side surfaces of the insulating base 11, and the main surface and side surfaces of the insulating base 11 inward. A notch 12 including the extended second inner surface 12b, an inner surface electrode 13 provided on the second inner surface 12b of the notch 12, and an inner surface electrode 13 of the notch 12; 1 on the inner surface 12a, the extended electrode 15 extending in a band shape from the second inner surface 12b to the inside of the notch 12, and the inner surface of the insulating base 11, extending behind the notch 12. Since the wiring conductor 14 connected to the output electrode 15 is provided, even if a large current is applied from the external circuit board 5 to the wiring board 1, the external circuit board 5 including the bonding material 6 such as solder is applied. The current path from the wiring board 1 to the wiring board 1 is extended in the vicinity of the connecting portion between the inner surface electrode 13 and the wiring conductor 14. As the width of the extension of 5 is increased, the current path is not rapidly reduced, current concentration in the vicinity of the connection portion between the inner surface electrode 13 and the wiring conductor 14 is suppressed, and the connection between the inner surface electrode 13 and the wiring conductor 14 is suppressed. It is possible to suppress disconnection or resistance abnormality of the portion, and to improve the electrical connection reliability between the inner surface electrode 13 and the wiring electrode 14. In the case where the electronic component is a two-light-emitting element, the wiring board 1 can emit light satisfactorily.

  Further, as in the example shown in FIGS. 1 and 3, the extension electrode 15 may be provided so that the end inside the notch 12 is provided along the notch 12 in a plan view. Further, as in the example shown in FIG. 4A, the width may be gradually reduced toward the side surface of the insulating base 11 provided along the notch 12 on the wiring conductor 14 side. Further, as in the example shown in FIG. 4B, the wiring conductor 14 may be provided along the notch 12 only on the wiring conductor 14 side.

  Further, as in the example shown in FIGS. 1 and 3, when the end inside the notch 12 of the extension electrode 15 is provided along the notch 12 in plan view, the external circuit board 5 Even if a large current is applied to the wiring board 1 from the end, the end of the extension electrode 15 is provided entirely along the notch 12, so that the applied current is widely applied to the extension electrode 15. The current path is effectively suppressed from suddenly decreasing, current concentration at the connection portion between the inner surface electrode 13 and the wiring conductor 14 is effectively suppressed, and the inner electrode 13 and the wiring electrode 14 The electrical connection reliability can be further improved.

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 wiring board for mounting a light emitting element on which a high light emitting element is mounted.

  According to the electronic device of the present embodiment, since the wiring board 1 having the above-described configuration and the electronic component 2 mounted on the wiring board 1 are provided, the electrical reliability and the electrical characteristics are improved. . When the electronic component 2 is a light emitting element, a light emitting device that can emit light satisfactorily over a long period of time can be obtained.

(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 differs from the electronic device according to the first embodiment described above in that the wiring conductor 14 is connected to the inner surface electrode 13 as in the examples shown in FIGS. This is the point that the thickness T1 is thicker at the connecting portion. In the example shown in FIGS. 8 to 13, the electronic component connecting electrode 17 is illustrated as a part of the wiring conductor 14 led to the bottom surface of the cavity 16.

  According to the wiring board 1 in the second embodiment, since the wiring conductor 14 has a thickness T1 at the connection portion with the inner surface electrode 13, a large current is applied from the external circuit board 5 to the wiring board 1. However, the current path is not reduced more rapidly, the current concentration at the connection portion between the inner surface electrode 13 and the wiring conductor 14 is further suppressed, and the connection portion between the inner surface electrode 13 and the wiring conductor 14 is broken or abnormal in resistance. Thus, the electrical connection reliability between the inner surface electrode 13 and the wiring electrode 14 can be further improved.

  Further, the thickness of the electronic component connecting electrode 17 when printing on the ceramic green sheet is reduced, and the warp in the electronic component 2 mounting region due to the firing shrinkage difference between the insulating base 11 and the electronic component connecting electrode 17 during firing is reduced. By making the deformation easy to suppress, the electronic component 2 can be satisfactorily mounted on the electronic component connecting electrode 17 or the connecting member 3 can be satisfactorily connected to the electronic component connecting electrode 17.

  In the second embodiment, the notch 12 is provided inside the notch having a width larger than that of the notch 12 in plan view, as in the example shown in FIG. The electrode 13 is provided on the second inner surface 12 b of the notch 12. Thus, when the notch 12 is provided inside the notch having a width larger than that of the notch 12 in plan view, the inner surface electrode 13 is formed when the notch 12 is formed. Or, without causing the extension electrode 15 to be divided, the inner electrode 13 or the extension electrode 15 from the insulating base 11 is peeled off, or the occurrence of a short circuit between the inner electrode 13 disposed adjacently is suppressed. Thus, the electronic device in which the wiring board 1 is used for the external circuit board 5 can be satisfactorily mounted on the external circuit board 5.

  Further, as in the example shown in FIG. 11, when the connection portion between the inner surface electrode 13 and the extension electrode 15 is curved, the bonding between the wiring board 1 and the external circuit board 5 is improved. In addition, when the curved shape is formed along the notch 12, the wiring board 1 and the external circuit board 5 can be bonded more favorably.

The insulating base 11 has an upper surface including a cavity 16 as in the examples 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. 8 to 11, the notch 12 is about 25% to 75% of the width of the side wall of the cavity.

  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 16 and the bottom surface of the cavity 16 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 those for the inner surface electrode 13 and the main surface electrode 13a, the wiring conductor 14, and the extension electrode 15.

  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 the innermost electrode 13, the main surface electrode 13 a, the wiring conductor 14, and the extended electrode 15 are outermost. It is preferable to deposit a gold plating layer on the surface. 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.

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

In the third manufacturing method, as in the example shown in FIG. 12A, the ceramic green sheets 111 and 211 to be the insulating base 11 are formed on the through hole 212 for the notch 12 and the through hole 116 for the cavity. And form. Then, as in the example shown in FIG. 12B, the conductor paste 113 for the inner surface electrode 13 is applied and printed on the inner surface of the through hole 212 to be the cutout portion 12 of the ceramic green sheet 211 by screen printing. . Further, the main surface electrode 13a is formed on the surface of the ceramic green sheet 211.
Conductive paste 113a for wiring, conductive paste 114 for wiring conductor 14, and conductive paste 117 for electronic component connecting electrode 17 are printed and applied by screen printing. Here, the conductor paste 113 for the inner surface electrode 13 and the conductor paste 114 for the wiring conductor 14 are formed to be connected. Further, the conductor paste 114 for the wiring conductor and the conductor paste 117 for the electronic component connecting electrode 17 are formed to be connected. Further, the conductor paste 114 for the wiring conductor 14 and the conductor paste 115 for the extension electrode 15 are applied and printed on the surface of the ceramic green sheet 111 by a screen printing method. Here, the conductor paste 114 for the wiring conductor 14 and the conductor paste 115 for the extension electrode 15 are formed to be connected. Then, by stacking and pressing the ceramic green sheets 111 and 211, the ceramic green laminate that becomes the insulating base 11 in which the conductor paste 114 for the wiring conductor 14 and the conductor paste 115 for the extension electrode 15 are connected to each other. By firing this ceramic raw laminate, as shown in FIG. 12C, the inner surface that becomes the cutout portion 12 has a recess 312 having an inner surface electrode 13 and an extended electrode 15. An insulating substrate 11 is formed. Here, when the ceramic green sheets 111 and 211 are laminated and pressed, the ceramic paste is overlapped so that the conductor pastes 114 for the wiring conductors 14 overlap each other, for example, about 0.1 mm to 0.5 mm in plan view. By forming the conductor paste 114 for the wiring conductor 14 and the conductor paste for the extension electrode 15 on the surface of the green sheet 111, the thickness of the connection portion between the wiring conductor 14 and the extension electrode 15 is increased. Can do. In this case, the conductor paste 114 for the wiring conductor 14 and the conductor paste 115 for the extension electrode 15 are each formed to a thickness of about 10 μm to 30 μm. The conductor paste 114 for the wiring conductor 4 on the ceramic green sheet 111 side connected to the conductor paste 115 for the extension electrode 15 is provided on the inner side along the second inner surface of the notch 12 in plan view. It is preferable that the width of the conductor paste 14 for the wiring conductor 14 on the ceramic green sheet 211 side is wider. Further, as in the example shown in FIG. 12 (d), the inner surface electrode 13 provided on the second inner surface 12 b of the notch 12 and the inner surface of the notch 12 are separated by dividing the recess 312. A wiring substrate 1 having an extension electrode 15 connected to the electrode 13 and provided on the first inner surface 12a of the notch 12 can be manufactured.

  In the wiring board 1 of the second embodiment, the above-described first manufacturing method or second manufacturing method may be used.

  Similar to the first embodiment, the wiring board 1 of the second 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.

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

  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 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 third embodiment of the present invention, as with the wiring board of the first embodiment, the inner surface electrode 13 is connected to the inner surface electrode 13 of the notch 12 and on the first inner surface 12a. And the extended electrode 15 extending in a strip shape to the inside of the notch 12, the applied current even if a large current is applied from the external circuit board 5 to the wiring board 1. Will also flow into the extension electrode 15 to suppress current concentration at the connection portion between the inner surface electrode 13 and the wiring conductor 14, and the connection portion between the inner surface electrode 13 and the wiring conductor 14 will be broken or abnormal in resistance. The electrical connection reliability between the inner surface electrode 13 and the wiring electrode 14 can be improved. In the case where the electronic component is a two-light-emitting element, the wiring board 1 can emit light satisfactorily. In this case, for example, an opening is provided in the module substrate 5, and the electronic device is joined to the lower surface of the module substrate 5 so as to cover the opening, whereby an electronic module is obtained.

  Further, even if the region of the main surface electrode 13a is small on the upper surface side of the insulating substrate 11, the inner surface electrode 13 and the extension electrode 15 can enhance the bondability with the external circuit board 5.

  In addition, since the wiring board 1 can be bonded to the external circuit board 5 by the 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.

  Similar to the first embodiment, the wiring board 1 of the third 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 present invention is not limited to the above-described embodiments, and various modifications can be made. In the above-described example, the notch 12, the inner surface electrode 13, and the extended electrode 15 are shown as being provided on each of two opposing side surfaces of the insulating base 11. 13 and the wiring board 1 provided with the extended electrodes 15 on all four side surfaces of the insulating base 11, and the wiring board 1 provided with the plurality of cutout portions 12 and the inner surface electrodes 13 and the extending electrodes 15 on the respective sides. May be. In the example shown in FIGS. 1 to 14, the insulating base 11 is formed of two or three insulating layers 11a. However, the insulating substrate 11 may be formed of four or more insulating layers 11a.

  Further, as in the example shown in FIG. 8, the wiring board 1 may have conductors other than wiring such as the electronic component mounting layer 18 and the central terminal layer 19. For example, these conductors can be manufactured using the same materials and methods as those for the inner surface electrode 13 and the wiring conductor 14 described above, and a plating layer similar to the inner surface electrode 13 and the wiring conductor 14 is deposited on the exposed surface. Has been. The electronic component mounting layer 18 is used, for example, for mounting the electronic component 2, and the central terminal layer 19 is connected to the external circuit board 5 in the same manner as the inner surface electrode 13, the main surface electrode 13 a, and the extended electrode 15, for example. Used for bonding. Further, as in the example shown in FIG. 13, the central terminal layer 19 also has an inner surface electrode 13 provided on the second inner surface 12b of the notch 12 and an extended electrode 15 provided on the first inner surface 12a. It does not matter if they are connected to each other.

  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
12a ... first inner surface
12b ... 2nd inner surface
13 ... Inner electrode
13a ... Main surface electrode
14 ... Wiring conductor
15 ... Extension electrode
16 ... Cavity
17 ... Electronic component connection electrodes
18 ... Electronic component mounting layer
19 ... Central terminal layer 2 ... Electronic component 3 ... Connection member 4 ... Sealing material 5 ... Module board (external circuit board)
51 ··· Connection pad 6 ··· Bonding material

Claims (4)

An insulating substrate having a main surface and side surfaces;
A notch including a first inner surface extending inward from the side surface of the insulating base and a second inner surface extending inward from the main surface and the side surface of the insulating base;
An inner surface electrode provided on the second inner surface of the notch;
An extended electrode connected to the inner surface electrode of the notch and extending in a band shape from the second inner surface to the inside of the notch on the first inner surface;
A wiring conductor provided inside the insulating base and connected to the extension electrode at the back of the notch ,
The wiring board is characterized in that the wiring conductor is thick at a connection portion with the inner surface electrode .   2. The wiring board according to claim 1, wherein, in a plan view, an end of the extending electrode inside the notch is provided along the notch. The wiring board according to claim 1 or 2 ,
An electronic device comprising: an electronic component mounted on the wiring board. The electronic device according to claim 3 is connected to a connection pad of a module substrate via a bonding material, and the bonding material extends from an end portion inside the notch portion of the extension electrode to the connection pad. An electronic module characterized by being inclined so as to spread.

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