JP2014143359A - Wiring board and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring board capable of depositing an electrolytic plating layer little varied in the thickness thereon.SOLUTION: A wiring board includes: an insulation substrate 11; a conductor 12 provided on the surface of the insulation substrate 11; and a plurality of wiring 13 for plating which are provided on surface or in the inside of the insulation substrate 11 and connected to the conductor 12. The plurality of wiring 13 for plating are connected to the conductor 12 so that the same number of the wiring 13 for plating is connected to a plurality of virtual regions obtained by dividing a loading part 121 constituting the conductor 12 equally into three or more.

Description

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

  2. Description of the Related Art Conventionally, wiring boards for mounting electronic components such as semiconductor elements or crystal resonators are provided on an insulating substrate made of an electrically insulating material such as ceramics, and on the surface and inside of an insulating base, and are made of metal such as metallization. And a conductor made of a material. The conductor is used as a mounting portion for mounting an electronic component or a wiring portion that is electrically connected to the electronic component.

  Such a wiring board may be provided with a wiring for plating for depositing an electrolytic plating layer on a conductor provided on the surface (see, for example, Patent Document 1).

JP 2009-147270 A

  However, the plating layer provided on the conductor by the electrolytic plating method may vary in thickness. This is because, for example, there is a difference in the distance between each of any two points of the conductor and the wiring for plating, and thus a difference occurs in the electrical resistance value between each of these two points and the wiring for plating. This is because a difference occurs in the thickness of the plating layer at these two points.

  In order to reduce the thickness variation of the plating layer, it is conceivable to increase the current value by increasing the width of the plating wiring in plan view. It is necessary to largely avoid wiring for plating. For this reason, there is a problem in that the degree of freedom for arranging the wiring is lowered.

  A wiring board according to one aspect of the present invention includes an insulating base, a conductor provided on the surface of the insulating base, and a plurality of plating wirings provided on or in the surface of the insulating base and connected to the conductor. Have. The plurality of plating wirings are connected to the conductors so that the same number of plating wirings are connected to a plurality of virtual regions equally divided into three or more conductors.

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

  The wiring board according to one aspect of the present invention is such that a plurality of plating wirings are connected to conductors so that the same number of plating wirings are connected to a plurality of virtual regions in which the conductors are equally divided into three or more. By being connected, the difference in distance from the wiring for plating can be reduced at any two points of the conductor, so that variations in the thickness of the plating layer can be reduced.

  Since the electronic device according to another aspect of the present invention has the wiring board having the above-described configuration and the electronic component mounted on the wiring board, the connection reliability between the electronic component and the wiring board can be improved.

It is a top view which shows the electronic device in the 1st Embodiment of this invention. It is an internal top view which shows the inside of the wiring board of the electronic device in the 1st Embodiment of this invention. It is a longitudinal cross-sectional view in the AA line of FIG. It is a top view which shows the multi-piece production wiring board for manufacturing the wiring board in the 1st Embodiment of this invention. It is a top view which shows the electronic device in the 2nd Embodiment of this invention.

  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 in the example shown in FIGS. The electronic device is mounted on a circuit board that constitutes an electronic component module, for example.

  The wiring board 1 includes an insulating base 11, a conductor 12 provided on the surface of the insulating base 11, and a plurality of plating wirings 13 provided on or in the insulating base 11 and connected to the conductor 12. Have. 1 to 3, the electronic device is mounted on the xy plane in a virtual xyz space. In FIG. 3, the upward direction means the positive direction of the virtual z axis.

The insulating substrate 11 includes a plurality of insulating layers 111, has an upper surface including a mounting area for the electronic component 2, and has a rectangular plate shape in plan view. The insulating substrate 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 agent such as a low melting point brazing material or a conductive resin. The

  The material of the insulating base 11 is an insulator such as ceramics or resin. When the material of the insulating substrate 11 is ceramic, for example, an aluminum oxide sintered body (alumina ceramic), an aluminum nitride sintered body, a mullite sintered body, a glass ceramic sintered body, or the like may be used. it can. Further, when the material of the insulating substrate 11 is a resin, as the material, for example, an epoxy resin, a polyimide resin, an acrylic resin, a phenol resin, a polyester resin, a fluororesin such as a tetrafluoroethylene resin, or a glass epoxy resin, etc. Can be used.

When the material of the insulating substrate 11 is an aluminum oxide sintered body, it is suitable for a raw material powder such as alumina (Al ₂ O ₃ ), silica (SiO ₂ ), calcia (CaO) and magnesia (MgO). An organic solvent and a solvent are added and mixed to produce a slurry. A ceramic green sheet is produced by forming this quagmire into a sheet by employing a conventionally known doctor blade method or calendar roll method. Next, the ceramic green sheet is appropriately punched, and a plurality of ceramic green sheets are laminated as necessary to form a generated shape, and the generated shape is fired at a high temperature (about 1500 to 1800 ° C.). Thus, the insulating base 11 is manufactured.

  When the material of the insulating base 11 is a resin, the insulating base 11 is manufactured by a transfer molding method, an injection molding method, or the like using a mold that can be molded into a predetermined wiring board shape, for example. For example, when the insulating base 11 is a glass epoxy resin, the base made of glass fiber is impregnated with an epoxy resin precursor, and the epoxy resin precursor is thermally cured at a predetermined temperature to thereby insulate the insulating base 11. Is produced.

The conductor 12 is provided on the surface and inside of the insulating base 11. The conductor 12 is led out from the inside of the insulating base 11 to the surface of the insulating base 11. The conductor 12 includes a mounting portion 121 for mounting the electronic component 2 and a wiring portion 122 for electrically connecting the electronic component 2 and an external circuit board. The wiring part 122 provided on the surface or inside of the insulating base 11 is composed of a wiring conductor provided on the surface or inside of the insulating base 11 and a wiring conductor positioned vertically through the insulating layer 111 constituting the insulating base 11. And through-hole conductors that electrically connect each other.

The plurality of plating wires 13 are for electrically connecting the mounting portion 121 of the conductor 12 and the power source for plating, and are provided on the surface and inside of the insulating base 11. Of the plurality of plating wirings 13, the first plating wiring 131 provided on the upper surface of the insulating base 11 is connected to the mounting portion 121. Of the plurality of plating wirings 13, the second plating wiring 132 provided inside the insulating base 11 is connected to the first plating wiring 131 and exposed from the side surface of the insulating base 11.

The plurality of plating wirings 13 may be connected to the plurality of virtual regions in which the conductors 12 are equally divided into three or more by the same number. In the present embodiment, the same number of mounting parts 121 are connected to a plurality of virtual areas 121a equally divided into four. That is, in the present embodiment, one of the plurality of plating wirings 13 is connected to each of the four virtual regions 121a.

As shown in the example shown in FIG. 1, each of the four virtual regions 121a includes a BB line that is a virtual straight line that passes through the center of the mounting portion 121 and extends in the x-axis direction, and a y-axis that passes through the center of the mounting portion 121. It is a part of the mounting part 121 divided | segmented by CC line which is a virtual straight line extended in the direction.

  The plurality of wirings 13 for plating are arranged symmetrically with respect to the BB line or CC line that is a virtual straight line, and symmetrical with respect to the BB line or CC line that is a virtual straight line. At this position, it is connected to the mounting portion 121.

Further, if the second plating wiring 132 has the same width as in the example shown in FIG. 2, it is effective in reducing variation in the thickness of the plating layer provided on the mounting portion 121. It is.

  The material of the conductor 12 and the plating wiring 13 can be a metal material such as tungsten (W), molybdenum (Mo), manganese (Mn), silver (Ag), or copper (Cu). The conductor 12 and the plating wiring 13 can be produced as follows. For example, if the insulating substrate 11 is made of an aluminum oxide sintered body, a conductor paste obtained by first adding and mixing an appropriate organic binder and solvent to a refractory metal powder such as W, Mo or Mn is prepared. To do. Next, the produced conductive paste is printed and applied in a predetermined pattern on a ceramic green sheet to be the insulating base 11 by a screen printing method in advance. Thereafter, the conductor 12 and the plating wiring 13 are deposited and formed at predetermined positions on the insulating base 11 by firing simultaneously with the ceramic green sheet to be the insulating base 11. When the conductor 12 is a through-wiring conductor, a through hole is formed in the green sheet by punching by a die or punching or laser processing, and the conductor paste for the conductor 12 is filled into the through hole by a printing method. Formed by.

A plating layer is deposited on the exposed surfaces of the conductor 12 and the plating wiring 13 by electrolytic plating. 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. Layer or a nickel plating layer with a thickness of about 1 to 10 μm and 0.1 to
A silver plating layer of about 1 μm is sequentially deposited. This can reduce the corrosion of the conductor 12 and the plating wiring 13. In addition, the conductor 12 and the electronic component 2 can be firmly fixed, the conductor 12 and the connection member 3 such as a bonding wire can be bonded, or the conductor 12 and the wiring of the external circuit board can be strongly bonded. Moreover, on the mounting part 121, the heat dissipation of the electronic component 2 can be improved by depositing a copper plating layer having a thickness of about 10 to 80 μm on the nickel plating layer.

The plating layer on the mounting portion 121 may be applied by an electrolytic plating method, and the plating layer on the wiring portion 122 may be applied by an electroless plating method. For example, the surface of the conductor 12 has a thickness of 0.5 to
After a nickel plating layer of about 5 μm and a gold plating layer of about 0.1 to 3 μm are deposited by an electroless plating method, a silver plating layer of about 0.1 to 4 μm is deposited on the surface of the mounting portion 121 by an electrolytic plating method. You can do that. For example, when the electronic component 2 is a light emitting element, a silver plating layer is provided on the surface of the mounting part 121 and a gold plating layer is provided on the surface of the wiring part 122, so that the light emitting element is directed toward the mounting part 121. The emitted light can be efficiently reflected and can be satisfactorily bonded to an external circuit board by the wiring part 122. Different plating layers can be applied to the mounting portion 121 and the wiring portion 122. Further, for example, since there is no need to provide a plating wiring connected to the wiring portion 122, the exposed portions from the side surfaces of the insulating base 11 of the plurality of plating wirings 13 can be reduced.

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 to the electronic component mounting region of the mounting portion 121 by a bonding member, and then the connecting member 3 such as a bonding wire.
The electrode of the semiconductor element and the wiring part 122 are electrically connected via the wiring board 1.
Mounted on. For example, when the electronic component 2 is a flip chip type semiconductor element, the semiconductor element is a semiconductor 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 element and the conductor 12 are mounted on the wiring board 1 by being electrically and mechanically connected. In addition, a plurality of electronic components 2 are mounted on the wiring board 1, and small electronic components such as resistance elements and capacitive elements 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.

The wiring board 1 is manufactured by using a multi-piece wiring board as in the example shown in FIG. The multi-piece wiring board includes a mother board 14 having a plurality of wiring board areas 141 and a peripheral area 142 provided around the plurality of wiring board areas 141, a conductor 12 provided on the surface of the mother board 14, and A plurality of wirings 13 for plating are provided on the surface and inside of the mother board 14 and connected to the conductor 12. In each of the plurality of wiring board regions 141, the plurality of plating wirings 13 are connected to the same number of plating wirings 13 to a plurality of virtual regions 121 a in which the mounting portion 121 is equally divided into three or more. In addition, it is connected to the mounting portion 121. The plurality of plating wirings 13 are electrically connected to the frame-shaped plating conductor 15 and the plating terminal 16 provided in the notch 143.

After the plating layer is deposited on the surface of the conductor 12 in the state of the multi-cavity wiring board, the multi-wiring wiring board is divided into individual pieces, whereby a plurality of wiring boards 1 can be manufactured. As a method of dividing the multi-cavity wiring board, a method of dividing a plurality of wiring board regions 141 by forming a dividing groove and bending the dividing groove can be used. The dividing groove is formed by pressing the cutter blade against the generated shape for the mother substrate 14, cutting it with a slicing device smaller than the thickness of the generated shape, or cutting the mother substrate 14 with a slicing device smaller than the thickness of the mother substrate 14. Can be formed. Further, a method of cutting the edge of the wiring board region 141 by a slicing method may be used.

The wiring board 1 of this embodiment includes an insulating base 11, a conductor 12 provided on the surface of the insulating base 11, and a plurality of plating electrodes provided on or in the surface of the insulating base 11 and connected to the conductor 12. And the plurality of plating wirings 13 are connected so that the same number of plating wirings 13 are connected to a plurality of virtual regions 121a in which the conductors 12 are equally divided into three or more. Connected to conductor 12. Because of such a configuration, the difference in distance between the plurality of wirings 13 for plating at any two points on the conductor 12 can be reduced, resulting in variations in the thickness of the plating layer provided on the conductor 12. Can be reduced.

In particular, in the mounting part 121 having a large area where a plurality of electronic components 2 are mounted, it is effective to reduce the occurrence of thickness variations in the plating layer on the surface of the mounting part 121. For example, when the electronic component 2 is a light emitting element, it is possible to reduce the occurrence of variations in reflectance due to variations in the thickness of the plating layer on the surface of the mounting portion 121.

  In the wiring board 1 of the present embodiment, in the above configuration, the plurality of plating wirings 13 are arranged symmetrically with respect to an imaginary straight line passing through the center of the conductor 12, so that a plurality of platings are formed on a part of the conductor 12. Since it is possible to further reduce the increase in the distance from the main wiring 13, it is effective to reduce the variation in the thickness of the plating layer provided on the conductor 12.

Further, as in the example shown in FIG. 2, when the second plating wirings 132 are arranged in parallel, the variation in the thickness of the plating layer provided on the mounting portion 121 is reduced. It is more effective.

  According to the electronic device of the present embodiment, since the wiring board 1 having the above configuration and the electronic component 2 mounted on the wiring board 1 are included, the connection reliability between the electronic component 2 and the wiring board 1 is improved. It can be improved.

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

The electronic device according to the present embodiment differs from the electronic device according to the first embodiment described above in that, as in the example shown in FIG. The connection parts are arranged at equal intervals. In such a case, the variation in distance between each part of the conductor 12 and the plurality of plating wirings 13 can be further reduced, so that the variation in the thickness of the plating layer provided on the conductor 12 is further reduced. It is effective.

The present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the number of the plurality of virtual areas 121a is not limited to four, and may be any number as long as there are three or more.

The plurality of plating wires 13 may be provided with the same number of plating wires 13 in each of the plurality of virtual regions 121a.

  The plating wiring 13 may be provided from the upper surface of the insulating base 11 to the side surface of the insulating base 11.

In addition, when a plating layer is deposited on the exposed surface of the wiring part 122 by an electrolytic plating method, the plating wiring 13 is also connected to the wiring part 122.

Further, the mounting part 121 may have a rectangular shape or other polygonal shapes. When the mounting portion 121 is rectangular in plan view, the plating wiring 13 may be connected to each corner of the mounting portion 121.

Further, a groove may be provided on the side surface of the insulating base 11, and a so-called castellation conductor having a conductor attached to the inner surface of the groove may be provided.

  Further, the wiring board 1 may have a cavity in which the electronic component 2 is accommodated on the upper surface. When the electronic component 2 is a light emitting element, it may have a reflective layer on the inner peripheral surface of the cavity.

1 ... Wiring board
11 ... Insulating substrate
111 ・ ・ ・ Insulating layer
12 ... Conductor
121 ・ ・ ・ Mounting part
122 ・ ・ ・ Wiring section
121a ..Virtual area
13 .... Plating wiring
131 ・ ・ ・ Wiring for first plating
132 ... Wiring for second plating
14 ... Mother substrate
141 ・ ・ ・ Wiring board area
142 ... Surrounding area
143 ... notch
15 ... Frame conductor for plating
16 .... Plating terminal 2 ... Electronic component 3 ... Connecting member 4 ... Sealing material

Claims (4)

An insulating substrate;
A conductor provided on the surface of the insulating substrate;
Provided on the surface or inside of the insulating base, and comprising a plurality of wirings for plating connected to the conductor;
The plurality of plating wires are connected to the conductor so that the same number of plating wires are connected to a plurality of virtual regions in which the conductor is equally divided into three or more. Wiring board to be used.   The wiring board according to claim 1, wherein the plurality of plating wirings are arranged symmetrically with respect to an imaginary straight line passing through a center of the conductor.   The wiring board according to claim 1, wherein connection portions of the plurality of plating wirings in the conductor are arranged at equal intervals. The wiring board according to claim 1;
An electronic device comprising: an electronic component mounted on the wiring board.

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