JP6298363B2 - Wiring board - Google Patents

Description

  The present invention relates to a wiring board provided with a surface conductor portion which is electrically independent on the surface of a substrate body made of ceramic and whose surface is coated with a plating film.

Usually, in a wiring board provided with an electrically independent metallization layer for sealing or a dummy pad on the surface of a substrate body made of ceramic or the bottom surface of a cavity opened on the surface, the metallization layer for sealing or It is necessary to coat the surface of the pad with a metal plating film. For this reason, on the side surface of the baked substrate main body, in order to be brought into contact with the plating electrode rod, the electrode metallization layer is formed in advance on the side surface to be electrically connected to the plurality of conductor parts including the pad. A method of removing all or part of the electrode metallization layer after plating is performed.
For example, after a connection metallization layer formed on the side surface of an insulating base made of ceramic is subjected to electrolytic plating on the surface of a desired metallization layer or the like, the connection metallization layer is polished so that a certain area or more remains. There has been proposed a method for manufacturing a package for housing a semiconductor element that effectively prevents the occurrence of cracks, chips, etc. in the insulating substrate by removing (see, for example, Patent Document 1).

However, even when the connection metallization layer formed on the side surface of the insulating base made of ceramic is selectively removed by polishing as in the method for manufacturing a package for housing a semiconductor element, one of the connection metallization layers to be removed should be removed. The side surface of the insulating substrate including the portion is strip-shaped including the ceramic portion constituting the side surface along the lateral (peripheral) direction parallel to the front and back surfaces of the insulating substrate or the thickness direction orthogonal to the front and back surfaces. It is necessary to polish it widely. As a result, there is a problem in that the time required for the polishing step including the ceramic portion increases and the cost increases.
Furthermore, after electrolytic plating, it is necessary to keep a certain distance or more away from each other in order to electrically insulate the ridges of the plurality of plating wires exposed on the side surfaces of the insulating base. Therefore, the method of selectively removing the metallization layer having a relatively large area by polishing as described above has a problem that it is extremely difficult to ensure insulation between adjacent plating wires. It was.

JP 2003-168754 A (pages 1-7, FIGS. 1-5)

  The present invention solves the problems described in the background art, and includes a surface conductor portion that is electrically independent on the surface of a substrate body made of ceramic and whose surface layer is coated with a plating film, and the surface conductor portion and other conductors. Provided is a wiring board that includes a plurality of plating wirings that are electrically connected to a portion, can easily secure insulation between the plating wirings, and has an electrode metallization layer removed during electrolytic plating removed with a small amount of polishing. , That is the subject.

Means for Solving the Problems and Effects of the Invention

In the present invention, a side surface of a substrate body made of ceramic is provided with a concave portion whose width increases from an intermediate position in the thickness direction on the side surface toward the back surface side, and is connected to the surface conductor portion on the inner wall surface of the concave portion. It was conceived to expose one end surfaces of a plurality of plating wirings including wirings apart from each other.
That is, the wiring board according to the present invention (Claim 1) is made of ceramic and has a front and back surfaces that are rectangular in plan view, and a substrate body having four side surfaces positioned therebetween, and a surface of the substrate body. One or a plurality of surface conductor portions formed on the substrate body, a plurality of external connection terminals formed on at least one of the surface, the back surface, and the side surface of the substrate body, and the surface and the back surface on any side surface of the substrate body Including a recess that is formed from an intermediate position to the back surface and that increases in width from the intermediate position toward the back surface, and a plurality of plating wirings that have one end surfaces exposed away from each other on the inner wall surface of the recess. A substrate, wherein the surface conductor portion and at least one of the plating wires are electrically connected, and the surface conductor portion and the external connection terminal are electrically independent from each other; Special To.

According to this, the surface conductor portion is electrically connected to one of the plurality of plating wirings whose one end surfaces are exposed away from each other on the inner wall surface of the recess, and the surface conductor portion is , And are not electrically connected to any of the plurality of external connection terminals. For example, when the surface conductor portion is a frame-shaped sealing metallization layer formed along the opening of the cavity that opens on the surface of the substrate body, the flat surface before the recess is formed in advance. Electrolytic plating is applied to the surface through the electrode metallization layer disposed on the side surface, and at the same time, electrolytic plating is applied to the surface of another surface conductor portion through the same electrode metallization layer as described above, By removing the back side of the side surface including the electrode metallization layer by polishing or the like to form a recess, the plurality of plating wires whose one end faces are exposed on the inner wall surface of the recess are electrically independent. It is said. Therefore, in use, the wiring board is such that the surface of the plurality of conductor portions including the surface conductor portion through which no current flows is reliably coated with the metal plating film. Further, by setting the interval between the plurality of plating wires (one end surface) exposed on the inner wall surface of the same recess so as to be a certain distance or more, a short circuit between the plating wires can be reliably prevented.
In addition, since the recess is formed so as to increase in width from an arbitrary intermediate position in the thickness direction of any side surface of the substrate body toward the back side of the side surface, man-hours and polishing time during manufacturing can be reduced. It can be reduced and the cost can be reduced.
In addition, since the concave portion is not exposed on the surface of the substrate body, various conductor portions can be easily arranged at desired positions without reducing the surface area.

The ceramic is a high-temperature fired ceramic such as alumina, mullite, or aluminum nitride, or a low-temperature fired ceramic such as glass-ceramic.
Further, the surface conductor portion is a conductor such as an electrically independent metallization layer for sealing or an electrically independent dummy pad as described below.
Further, when the ceramic is a high-temperature fired ceramic, for example, W or Mo is applied to the surface conductor portion, the plating wiring, and the external connection terminal, and when the ceramic is a low-temperature fired ceramic, For example, Ag or Cu is applied.
In addition, the surface of the substrate body includes a bottom surface of a cavity opened on the center side of the surface or a step portion positioned on the bottom surface side. In this form, the sealing metallization layer is formed on the surface surrounding the opening of the cavity.
Furthermore, one end of a lead is individually joined to the surface of each of the external terminals formed on the side surface of the substrate body. The side surface and the side surface on which the recess is formed are different from each other and may be provided on the same side surface.

The intermediate position on the side surface is not only near the center between the front surface and the back surface in the thickness direction of the side surface, but also an arbitrary position between the front surface and the back surface.
Furthermore, the concave portion has a convex arcuate shape (semicircular shape, semielliptical shape, semielliptical shape), a trapezoidal shape, or an isosceles triangular cross-sectional shape on the surface side of the substrate body in a side view, As viewed from the bottom, it has a convex arc shape, trapezoidal shape, or isosceles triangle shape from the side surface of the substrate body toward the back surface.
Further, the plurality of plating wirings whose one end surfaces are exposed to be separated from each other on the inner wall surface of the recess are a single plating formed in advance on a side surface including a plurality of ceramic layers laminated to constitute the substrate body. One end is individually connected to the electrode for electrode, and after applying predetermined electrolytic metal (Ni, Au) plating on the surface of the metallization layer for sealing or the pad for dummy via each plating wiring, The back side of the side surface including the plating electrode is disposed on the inner wall surface of the recess formed by, for example, using a micro grinder, or grinding or polishing by laser irradiation.
In addition, the lead end portions of the leads may be individually joined to the plurality of external connection terminals formed on the peripheral portion or the side surface of the surface of the substrate body.

Further, the present invention includes a wiring board (Claim 2) in which the surface conductor portion is a sealing metallization layer or an electrically independent pad.
According to this, the sealing metallized layer formed along the opening of the cavity opened on the surface of the substrate body and in which current does not flow during use, or a component in which current does not flow during use among a plurality of pads For example, the surface of the dummy pad or the alignment mark pad used for mounting the substrate is a wiring substrate that is reliably covered with two layers of Ni plating film and Au plating film, for example. .
The pads are formed on the surface of the substrate body, or the bottom surface or step of the cavity, and form a pattern as a whole with adjacent conductive pads, or alignment for positioning the wiring board. Mark.

Furthermore, the present invention includes a wiring board (Claim 3) in which at least one of the plurality of plating wirings is electrically connected to at least a part of the external connection terminals.
According to this, at least one of the plurality of plating wirings, excluding the plating wiring electrically connected to the surface conductor portion, is electrically connected to some or all of the plurality of external connection terminals. Therefore, the surface of the plurality of external connection terminals is also a wiring board that is reliably coated with the same metal plating film as the surface of the surface conductor portion.
Further, the present invention includes a wiring board (Claim 4) in which the crossing angle in a side view formed by the opening edge of the side surface in the recess and the back surface is an obtuse angle.
According to this, since the crossing angle of the side view formed by the opening edge of the side surface in the concave portion and the back surface forms an obtuse angle of more than 90 degrees, the ceramic portion in the vicinity of the crossing portion is subjected to impact such as separation. The situation which is not carelessly lacked can be suppressed.

In addition, according to the present invention, the substrate body is formed by laminating a plurality of ceramic layers, and one or more end surfaces of the three or more plating wirings exposed on the inner wall surface of the recess are adjacent to any ceramic layer. And a wiring board (claim 5) that is exposed to the side surface side of the substrate main body and is provided so as to gradually increase from the ceramic layer at the intermediate position of the side surface toward the ceramic layer on the back surface side.
According to this, in the inner wall surface of the recess formed from the intermediate position between the front surface and the back surface of any one of the side surfaces of the substrate main body to the back surface, and the width increases from the intermediate position toward the back surface, One or more exposed end faces of the three or more plating wirings are exposed to the side surface of the substrate body from any of the adjacent ceramic layers, and gradually from the ceramic layer at an intermediate position of the side surface toward the ceramic layer on the back surface side. It is installed side by side so as to increase. As a result, an inadvertent short circuit between a plurality of adjacent plating wires can be easily prevented.

  When there are three plating wires, one end surface of the plating wire exposed on the inner wall surface of the recess is disposed on the intermediate position side of the side surface and two on the back surface side. In the case of four, the intermediate position side: 1 → back side: in the order of 3, in the case of 5, in the order of 1 → 2 → 2 in order from the intermediate position side to the back side, In the case of six, it is arranged for each of the plurality of ceramic layers in the order of 1 → 2 → 3 in order from the intermediate position side to the back surface side. In these cases, one end surface of all the wirings for plating, for example, exhibits a checkered pattern or a scale pattern as a whole, so that a short circuit between each other can be reliably prevented in a relatively narrow recess. It becomes possible.

The top view which shows the wiring board of one form by this invention. FIG. 2 is a partial vertical cross-sectional view taken along arrows X1-X1 and X2-X2 in FIG. 1. The perspective view which shows the side surface vicinity along the vision of the arrow Y in FIG. The side view which shows the side surface of the board | substrate body in which the said recessed part was formed. The enlarged view of the side surface similar to the above which shows arrangement | positioning of the form from which the wiring for plating differs. (A) is a perspective view which shows the side surface vicinity before forming a recessed part, (B) is a vertical sectional view of the center part in the width direction of this side surface. (A) is a perspective view which shows the side surface vicinity after a recessed part was formed, (B) is a vertical sectional view of the center part in the width direction of this side surface. The perspective view which shows the wiring board of a different form by this invention. FIG. 9 is a vertical sectional view taken along the line ZZ in FIG. 8. The vertical sectional view which shows the different board | substrate body in the said wiring board.

Hereinafter, modes for carrying out the present invention will be described.
FIG. 1 is a plan view showing a wiring board 1a according to an embodiment of the present invention, FIG. 2 is a partial vertical sectional view taken along arrows X1-X1 and X2-X2 in FIG. 1, and FIG. It is a perspective view which shows the side surface 5 vicinity in which the recessed part 11 along the vision of the arrow Y in FIG. 1 was formed.
As shown in FIGS. 1 to 3, the wiring board 1 a includes a box-shaped board body 2 a as a whole, a sealing metallization layer (surface conductor part) 10 formed on almost the entire surface 3, A plurality of external connection terminals 17 formed on a pair of side surfaces 5 which are long sides facing each other in the substrate body 2a and a pair of symmetrically formed on a pair of side surfaces 5 which are short sides facing each other on the substrate body 2a. A recess 11 and a plurality of plating wires 12 and 14 whose one end faces are exposed apart from each other are provided on the inner wall surface of each recess 11.

The substrate body 2a is formed by integrally laminating a plurality of ceramic layers, as will be described later, and has a front surface 3 and a back surface 4 having a rectangular (rectangular) outer shape in plan view, and a pair of each. It has four side surfaces 5 which are a long side and a short side. The corner child between the adjacent side surfaces 5 and 5 is provided with a concave and curved side surface 5r.
A rectangular (rectangular) cavity 6a is opened on the surface 3 of the substrate body 2a in plan view, and the sealing metallized layer 10 is rectangular frame-shaped in plan view so as to surround the opening of the cavity 6a. Is formed. When an electronic component (not shown) such as a semiconductor element is mounted in the cavity 6a, four sides are placed on the sealing metallization layer 10 in order to seal the cavity 6a. A metal lid (not shown) placed in contact is joined by seam welding or the like.
The cavity 6a includes a bottom surface 7 having a rectangular shape in plan view and an inner surface 8 having four sides erected from the four sides of the bottom surface 7 to the surface 3 side. A plurality of element mounting pads 9 that are individually electrically connected to the plurality of electrodes are formed. A part of the element mounting pad 9 includes a dummy pad 9a which is a surface conductor portion of the present invention.

Further, as shown in FIGS. 2 and 3, the sealing metallization layer 10 is a via conductor extending vertically in a vertically long side wall located between the side surface 5 of the substrate body 2a and the inner surface 8 of the cavity 6a. The via conductor 13 is connected to the lower end and the other end of the via conductor 13 and is electrically connected to the plating wiring 12 whose one end surface is relatively exposed on the surface 3 side of the inner wall surface 11f of the recess 11. Has been.
On the other hand, of the plurality of element mounting pads 9, a pair of element mounting pads (surface conductor portions) 9a located on the side 5 of the short side are dummy pads that are electrically independent when in use, Plating in which the lower end and the other end of the via conductor 15 are connected via a via conductor 15 that hangs down from the bottom surface 7 of the cavity 6a, and one end surface is exposed relatively to the back surface 4 side of the inner wall surface of the recess 11. It is electrically connected to one of the wirings 14 for use.
The other plating wiring 14 is connected to at least one of the element mounting pads 9 other than the dummy pads 9a and the plurality of external connection terminals 17 via internal wiring (wiring layer and via conductor) (not shown). It is electrically connected to the part.
As shown in FIGS. 1 and 3, the upper ends of the leads 18 are individually joined to the surfaces of the plurality of external connection terminals 17, and the lower ends of the leads 18 are in a horizontal posture (not shown). They are connected to each other by a single outer frame.

As shown in FIGS. 1 to 3, the recess 11 is formed so that the width increases from an intermediate position between the front surface 3 and the back surface 4 to the back surface 4 for each side surface 5 of the short side of the substrate body 2 a. An inner wall surface 11f made of a curved surface that protrudes toward the cavity 6a and has a substantially quarter-shaped sphere has one end surface of the plating wiring 12 on the relatively front surface 3 side, and on the relatively back surface 4 side and left and right sides. One end surfaces of the pair of plating wires 14 are exposed.
As exemplified by the short side surface 5 of FIG. 4, the substrate body 2a is formed by laminating a plurality of ceramic layers (ceramics) c1 to c5. On the inner wall surface 11f of the recess 11 located on the side surface 5, the distance a between the pair of left and right plating wires 14 on the relatively back surface 4 side, and the plating surface on the relatively surface 3 side with the pair of plating wires 14 The interval b with the wiring 12 is substantially the same as each other, and is set to be equal to or longer than the distance at which the plating wirings 12 and 14 are not short-circuited with each other. Therefore, a total of three of the above-described plating wires 12 and 14 are arranged so that the central portion is individually positioned for each corner portion of the equilateral triangle as a whole in a side view.

As shown in FIG. 4, the crossing angle θ1 between the opening of the side surface 5 in the recess 11 and the back surface 4 is an obtuse angle exceeding 90 degrees. As a result, it is possible to prevent a situation (so-called chipping) in which the ceramic in the vicinity of the intersection of the opening of the side surface 5 and the back surface 4 in the concave portion 11 is locally or partially inadvertently missing.
When the ceramic layers c1 to c5 are made of a high-temperature fired ceramic such as alumina, the element mounting pads 9, 9a, the surface conductor metallizing layer 10 for sealing, the plating wires 12, 14, and the via conductors 13, 15 are used. The external connection terminals 17 and the like are made of W, Mo, or an alloy based on one of them. On the other hand, when the ceramic layers c1 to c5 are made of a low-temperature fired ceramic such as glass-ceramic, the conductors such as the element mounting pads 9 and 9a and the sealing metallized layer 10 are based on Cu or Ag or one of them. It is supposed to be made of an alloy.
The lead 18 is made of Kovar, 42 alloy, 194 alloy or the like, and constitutes a single lead frame (not shown) including the outer frame portion.

FIG. 5 is an enlarged side view of the side surface 5 similar to FIG. 4, and the inner wall surface 11 f of the recess 11 formed on the side surface 5 has one plating wiring 12 relatively on the surface 3 side. A pair of left and right plating wires 14 that are relatively middle are exposed at a distance a apart from each other, and three plating wirings 16 are exposed at a relatively back surface 4 side at a distance a. . Further, in the thickness direction between the front surface 3 and the back surface 4 of the inner wall surface 11f of the recess 11, the space between the plating wires 12 and 14 and the space between the plating wires 14 and 16 are set at the same interval b as the interval a. They are exposed away from each other.
That is, a total of six plating wirings 12, 14, and 16 are arranged so as to exhibit a checkerboard pattern or a scale pattern as a whole in a side view, and the distances a and b can be insulated from each other. Therefore, it is difficult to short-circuit each other.
It should be noted that the plating wiring 16 having one end surface exposed relatively to the back surface 4 side is appropriately electrically connected to the element mounting pads 9 other than the dummy pads 9a and at least a part of the plurality of external connection terminals 17. It is connected.
Further, the crossing angle θ2 between the opening of the side surface 5 in the recess 11 in FIG. 5 and the back surface 4 is also an obtuse angle exceeding 90 degrees.

The wiring board 1a as described above was manufactured as follows.
Five ceramic green sheets containing alumina powder or the like are produced in advance, and drilling is performed at appropriate positions for each green sheet to form an opening hole for the cavity 6a and a through hole having a relatively small diameter. Via conductors 13 and 15 were formed by filling a conductive paste containing W powder or the like every time. Next, on the at least one of the front and back surfaces of each green sheet, the same conductive paste as described above is screen-printed to form unfired element mounting pads 9 and 9a having a predetermined pattern, sealing metallization layer 10, and plating. Wirings 12 and 14 (16) were formed. Next, the five green sheets were laminated and pressure-bonded in a predetermined order, and then fired at a predetermined temperature range.
As a result, the ceramic layers c1 to c5 are laminated, and the sealing metallized layer 10 is formed on almost the entire surface of the rectangular frame-shaped surface 3, and a plurality of elements are formed on the bottom surface 7 of the cavity 6 opening on the surface 3. A ceramic having a substrate body 2a in which mounting pads 9 and 9a are formed, and one end surfaces of the plating wirings 12 and 14 (16) are individually exposed on the back surface 4 side of a pair of opposing short side surfaces 5 A laminate was obtained.

Further, as shown in FIGS. 6 (A) and 6 (B), in each of the pair of short side surfaces 5 in the substrate main body 2a, in an area including the plating wirings 12 and 14 (16) in which one end surfaces are individually exposed. The same conductive paste as described above was screen-printed to form an electrode metallization layer 19 having a rectangular side view. One end portions of the plating wirings 12 and 14 (16) are individually connected to the metallized layer 19 respectively.
Subsequently, the same conductive paste as described above is screen-printed on each of the pair of long side surfaces 5 in the substrate body 2a to form a plurality of external connection terminals 17, and the ceramic laminate including these is used in a heating furnace. The metallized layer 19 and the external connection terminal 17 were cured by being inserted.
Next, with the electrode metallization layer 19 and the outer frame part connecting the lower ends of the leads 18 joined to each of the plurality of external connection terminals 17, plating electrode pins (not shown) are in contact with each other. The ceramic laminate was sequentially immersed in an electrolytic Ni plating tank and an electrolytic Au plating tank. As a result, the Ni mounting film and the Au plating film were sequentially coated with the required thickness on the surfaces (exposed surfaces) of the element mounting pads 9, 9a, the sealing metallization layer 10, and the external connection terminals 17. In the case of the external connection terminal 17, the surface of the external connection terminal 17 including the lead 18 is coated with the Ni plating film alone in advance, and the upper ends of the leads 18 are individually joined by brazing. On the other hand, a Ni plating film and an Au plating film were coated.

Thereafter, for the region on the back surface 4 side in the side surface 5 of each short side including the electrode metallization layer 19, a polishing operation by a micro grinder so that the axial direction spans between the side surface 5 and the back surface 4, This was performed until the electrode metallization layer 19 was removed.
As a result, as shown in FIGS. 7 (A) and 7 (B), it swells in an arc shape in the vicinity of the horizontal center of each side surface 5 on the short side and from the back surface 4 side to the front surface 3 side in a side view. In addition, the concave portion 11 that enters the arc shape is formed in the center side of the back surface 4, and the wiring substrate 1 a in which one end face of the plating wirings 12 and 14 (16) is exposed on the inner wall surface 11 f is obtained. I was able to.
In addition, you may perform the said grinding | polishing process by the laser processing performed by irradiating various laser beams, such as a carbon dioxide gas.
Each of the above steps may be performed in a multi-cavity form. In that case, the curved side surface 5r is provided between the adjacent long side, short side, and side surfaces 5 and 5 in the substrate carrier 2a. It is formed.

According to the wiring substrate 1a as described above, the element mounting pad 9a and the sealing metallized layer 10 which are surface conductor portions are a plurality of platings whose one end surfaces are exposed apart from each other on the inner wall surface 11f of the recess 11. One of the wirings 12 and 14 (16) for electrical connection, and the dummy pad 9a and the sealing metallization layer 10 are electrically connected to any of the plurality of external connection terminals 17. Not connected.
That is, the sealing metallized layer 10 is subjected to electrolytic Ni and Au plating on the surface in advance through the electrode metallized layer 19 disposed on the flat side surface 5 before the recess 11 is formed. At the same time, after electrolytic Ni and Au plating are applied to the surface of the element mounting pads 9 and 9a through the same electrode metallization layer 19, the back surface 4 side of the side surface 5 including the electrode metallization layer 19 is reduced. By removing the polishing amount to form the recess 11, one end surfaces of the plurality of plating wirings 12 and 14 (16) are exposed away from each other on the inner wall surface 11 f of the recess 11, and the plurality of plating wirings are provided. 12, 14 (16) is electrically independent.
For this reason, when used, the wiring substrate 1a in which the surfaces of the sealing metallized layer 10 and a part of the element mounting pads (dummy pads) 9a, in which no current flows, are reliably coated with Ni and Au plating films, It has become.

Furthermore, by setting the distances a and b between the plurality of plating wirings (one end surfaces) 12 and 14 (16) exposed on the inner wall surface 11f of the same recess 11 so as to be a certain distance or more, A short circuit between the wirings 12 and 14 (16) can be reliably prevented.
In addition, the concave portion 11 is formed so that the width increases from an arbitrary intermediate position in the thickness direction of the side surface 5 of the short side in the substrate body 2 toward the back surface 4 side of the side surface 5. The number of steps, polishing amount, and polishing time can be reduced and the cost can be reduced. Moreover, the concave portion 11 is not exposed on the front surface 3 of the substrate body 2 and is formed from the intermediate position of the side surface 5 to the back surface 4 side, and the peripheral portion of the front surface 3 adjacent to the side surface 5 is not removed. Various conductors formed on the front surface 3 and recessed conductors formed between the front surface 3 and the back surface 4 of the corner portion between the adjacent side surfaces 5 can be reliably disposed in the initial form.

Therefore, in use, the wiring substrate 1a is provided in which the metal (Ni and Au) plating film is reliably coated on the surface of the surface conductor portion of the sealing metallized layer 10 and the dummy pad 9a where current does not flow. be able to.
The concave portion 11 may be formed only at any one of the side surfaces 5 of the four sides. Among these, when forming on the long side surface 5, it may be formed between the plurality of external connection terminals 17 formed on the side surface 5.
Further, a metal plate made of Kovar or the like on which electronic parts such as semiconductor elements are mounted later on the plurality of element mounting pads 9 and then four sides are placed on the metallization layer 10 for sealing. Are joined by seam welding (resistance welding) or the like.
Further, the plurality of external connection terminals 17 may be formed on the back surface 4 of the substrate body 2a.

FIG. 8 is a perspective view showing a wiring board 1b of a different form, and FIG. 9 is a vertical cross-sectional view taken along the line ZZ in FIG.
As shown in FIGS. 8 and 9, the wiring board 1 b is formed on the central side of a substrate body 2 b that has a flat plate shape as a whole and a surface 3 that is square (rectangular) in plan view in the board body 2 b. A plurality of element mounting pads 9, 9b, a plurality of external connection terminals 20, 20b formed along the periphery of the front surface 3, and four sides located between the front surface 3 and the back surface 4 of the substrate body 2b Of the side surfaces 5, two concave portions 11 formed for each side surface 5 adjacent to the front side and the right side in FIG. 8, and the same plating as described above with one end surface exposed individually on the inner wall surface of each concave portion 11. Wirings 12 and 14 and a plurality of external connection terminals 24 formed on the back surface 4 of the substrate body 2b.
Among the nine element mounting pads 9 and 9b, which are located on the center side of the surface 3 of the substrate body 2b and are three in a vertical and horizontal direction in plan view, the center between the front side and the right side in FIG. There is a dummy pad (surface conductor portion) 9b through which no current flows during use. Further, in FIG. 8, in the middle between the front side surface 5 and the right side surface 5 of the substrate body 2b, the same dummy terminals (surface conductor portions) 20b are located one by one.

Further, the end surfaces of the same plating wirings 12 and 14 are exposed on the inner wall surface 11f of the recess 11 so as to be positioned at each corner of the triangle in a side view.
Further, as illustrated in FIG. 9, the substrate body 2b is formed by integrally laminating the same ceramic layers (ceramics) c1 to c5 as described above, and a wiring layer having a predetermined pattern is provided between the ceramic layers c1 to c5. 22 is formed, and between the wiring layers 22 and between the uppermost wiring layer 22 and the element mounting pad 9 or the external connection terminal 20, any via that individually penetrates the ceramic layers c2 to c5. The conductors 23 are electrically connected. Further, a plurality of external connection terminals 24 are formed on the back surface 4 of the substrate body 2b. The external connection terminals 24 are electrically connected to the lowermost wiring layer 22 via via conductors 23 that penetrate the ceramic layer c1. It is connected to the.
The external connection terminals 20, 20b, 24, the wiring layer 22, and the via conductor 23 are also made of any of W, Mo, Cu, Ag, and the like in the same manner as described above.

As shown in FIG. 9, the plating wire 12 having one end surface exposed on the surface 3 side of the inner wall surface 11f of the recess 11 is connected to the other end portion of the plating wire 12 extending between the ceramic layers c2 and c3. Among the external connection terminals 20, the dummy connection (part) 20 b is electrically connected via the via conductor 13. Of the plating wires 14 whose one end surface is exposed on the back surface 4 side of the inner wall surface 11f of the recess 11, one plating wire 14 is the other of the plating wires 14 extending between the ceramic layers c1 and c2. It is electrically connected to the dummy element mounting pad 9b through a via conductor 15 connected to the end. Further, the other plating wiring 14 is electrically connected to any (part) of the external connection terminals 20 via any of the wiring layers 22 and via conductors 23.
An electronic component 26 such as a semiconductor element is mounted above the element mounting pads 9 and 9b. A plurality of electrodes (not shown) located on the upper surface side of the electronic component 26 can be individually conducted through the external connection terminals 20 and bonding wires (not shown). Alternatively, the tip of the lead having the horizontal orientation may be individually joined to the surface of the external connection terminal 20.

FIG. 10 is a vertical sectional view showing a different board body 2c in the wiring board 1b. As shown in FIG. 10, the substrate body 2c is formed by laminating the same ceramic layers c1 to c5 as described above, and the bottom surface 7 and four sides of the surface 3 are rectangular (square) when viewed from the center. A cavity 6c having an inner surface 8 and penetrating the ceramic layers c4 and c5 is opened. On the bottom surface 7 of the cavity 6c, a total of nine element mounting pads 9 and 9b are formed in the same pattern as described above, three by three in the vertical and horizontal directions in plan view.
Note that one end surfaces of the same plating wirings 12 and 14 are exposed on the inner wall surface 11f of the concave portion 11 located on any one of the side surfaces 5, and the other end portions of the recesses 11 are formed on the dummy external surface in the same manner as described above. The connection terminal 20b, the dummy element mounting pad 9b, or the external connection terminal 20 is electrically connected via the via conductors 13 and 15 or the wiring layer 22 and the via conductor 23. .
Further, a sealing metallization layer (10) having a square shape in plan view may be further formed on the surface 3 of the substrate body 2c along the opening of the cavity 6c.

Substrate main body 2b, 2c, concave portion 11, plating wirings 12, 16, wiring board provided with dummy element mounting pads 9b on the surface conductor portion, dummy external connection terminals 20b, external connection terminals 20, 24, etc. The effect similar to that of the wiring board 1a can be obtained by 1b.
The concave portion 11 may be formed on only one side surface 5 of the substrate bodies 2b and 2c, for each side surface 5 facing each other, or for each side surface 5 on three sides.
Further, on the inner wall surface 11f of the concave portion 11, as shown in FIG. 5, one end surfaces of the plating wirings 12, 14, and 16 from the front surface 3 side to the back surface 4 side are the same checkerboard (scale) pattern as in the previous period. It may be exposed.

The present invention is not limited to the embodiments described above.
For example, two or more recesses 11 may be provided on the same side surface 5 of the substrate bodies 2a to 2c.
Further, the inner wall surface 11f of the recess 11 is not limited to a sphere shape of about a quarter as a whole, but the whole is a semi-cylindrical shape, and a form in which deformed triangular pyramids are arranged symmetrically on both sides in the lateral direction, and the whole is a triangle. Form that is columnar and symmetrically arranged with deformed triangular pyramids on both sides in the horizontal direction, or an overall ellipsoid of about 1/4 or about 1/4 of a cylinder and about 1/8 on both sides It is good also as a form which symmetrically arranged the spherical body of.
Further, the concave portion 11 may be formed by using both a polishing process using a micro grinder or the like and a laser process using laser irradiation.
In addition, the front surface 3 and the back surface 4 of the substrate body 2a of the wiring substrate 1a may be square in plan view, and the bottom surface 7 of the cavity 6a may be similar to a square shape, or the wiring substrate 1b The front surface 3 and the back surface 4 of the substrate body 2b may have a rectangular shape in plan view, and the bottom surface 7 of the cavity 6a may have a similar rectangular shape.

  According to the present invention, a surface conductor portion that is electrically independent on the surface of a substrate body made of ceramic and whose surface layer is coated with a plating film, and a plurality of plating wirings that conduct to the surface conductor portion and other conductor portions Thus, it is possible to easily ensure insulation between the plating wirings, and to reliably provide a wiring board in which the electrode metallization layer used during electrolytic plating is removed with a small amount of polishing.

1a, 1b ………… Wiring boards 2a ～ 2c ………… Board body 3 …………………… Front side 4 …………………… Back side 5 …………………… Side surface 9a, 9b …… Dummy pad (surface conductor)
10: Metallizing layer for sealing (surface conductor)
11 ............... Recess 11f ............ Inner wall surface 12, 14, 16 ... Plating wiring 17, 20, 24 ... External connection terminal 20b ......... Dummy terminal (surface conductor) )
c1 to c5 ............ Ceramic layer (ceramic)
θ1, θ2 ………… Cross angle

Claims (5)

A substrate body made of ceramic and having a front surface and a rear surface that are rectangular in a plan view, and four side surfaces located between them,
One or more surface conductors formed on the surface of the substrate body;
A plurality of external connection terminals formed on at least one of the front surface, the back surface, and the side surface of the substrate body;
A concave portion that is formed from an intermediate position between the front surface and the back surface on any side surface of the substrate body to the back surface, and has a width that increases from the intermediate position toward the back surface;
A wiring substrate including a plurality of plating wirings, one end surfaces of which are exposed apart from each other on the inner wall surface of the recess,
The surface conductor portion and at least one of the plating wires are electrically connected, and the surface conductor portion and the external connection terminal are electrically independent from each other.
A wiring board characterized by that. The surface conductor is a metallization layer for sealing, or an electrically independent pad.
The wiring board according to claim 1. At least one of the plurality of plating wirings is electrically connected to at least a part of the external connection terminal.
The wiring board according to claim 1 or 2, wherein The crossing angle of the side view formed by the opening edge of the side surface in the recess and the back surface is an obtuse angle.
The wiring board according to any one of claims 1 to 3, wherein The substrate body is formed by laminating a plurality of ceramic layers, and one end surfaces of the three or more plating wirings exposed on the inner wall surface of the recess are exposed from one of adjacent ceramic layers to the side surface side of the substrate body. In addition, it is provided side by side so as to gradually increase from the ceramic layer at the intermediate position of the side surface toward the ceramic layer on the back surface side,
The wiring board according to any one of claims 1 to 4, wherein the wiring board is provided.

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