JP2007251017A - Wiring substrate, multipartite wiring substrate, and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring substrate having a notch-portion conductor on each side surface of its substrate body whereon a metal plating layer having an sufficient thickness is formed, and provide a multipartite wiring substrate for obtaining the many wiring substrates, and further, provide a manufacturing method of the multipartite wiring substrate. <P>SOLUTION: The wiring substrate p1 is so constituted as to laminate upper-layer-side ceramic layers c2, c3 and a lower-layer-side ceramic layer c1, and includes a substrate body 1 having front and rear surfaces 2, 3, a notch 5 formed on each side surface 4 of the lower-layer-side ceramic layer c1 of the substrate body 1, a notch-portion conductor 6 formed in the notch 5, and an insulating portion 10 so formed as to cover at least the upper end 6c of a notch conductor 6 which has a curved surface 11. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wiring board having a notch conductor in a notch on the back side of the substrate body, a multi-piece wiring board having an inner wall conductor in a non-through hole opened in the back side of the base board, and the multi-piece wiring board It relates to the manufacturing method.

For example, a frame having a rectangular parallelepiped and having a through hole on the upper surface of a belt-like substrate is laminated, and each of the four corners of the substrate is positioned below the frame and cut out in a plan view. There has been proposed a light emitting element storage package having a notch and having a side conductor formed on the inner peripheral surface of the notch (see, for example, Patent Document 1).
In the light emitting element storage package, since the arc-shaped side conductors are formed on each of the four corners of the base with a large surface area, the electrode pads formed on the bottom surface of the base are used as the wiring conductors of the external electric circuit board. At the time of connection, a large solder meniscus is formed, so that the bonding strength can be increased.

Japanese Unexamined Patent Publication No. 2004-253711 (pages 1 to 12, FIGS. 1 and 2)

  However, when a large number of the light emitting element storage packages are manufactured, they are formed on the inner peripheral surface of a non-through hole that opens on the back surface of a large-size insulating substrate, and then divided into the plurality of arc-shaped side conductors. Since the plating solution does not easily circulate on the cylindrical inner wall conductor, a sufficiently thick plating layer cannot be formed. For this reason, the multi-sided substrate is divided into a plurality of packages, and the four side conductors in each of the obtained packages are not covered with, for example, a plating layer made of Au with a sufficient thickness. As a result, when connecting the side conductors to the wiring conductors of the external electric circuit board, there is a problem that the soldering wettability is low, so that the bonding strength of the soldering becomes insufficient.

  The present invention solves the problems described in the background art, and has a wiring board having a notched conductor in which a metal plating layer having a sufficient thickness is formed on the side surface of the board body, and a large number of pieces for obtaining such a wiring board. It is an object of the present invention to provide a wiring board and a method for manufacturing such a multi-cavity wiring board.

Means for Solving the Problems and Effects of the Invention

In order to solve the above-mentioned problems, the present invention makes it possible to easily circulate the plating solution to the inner wall conductor of the multi-piece wiring board that will be the cutout conductor of the wiring board, and to form a sufficiently thick plating layer. It was designed with the idea in mind.
That is, the wiring board of the present invention (Claim 1) is configured by laminating an upper ceramic layer and a lower ceramic layer, and has a substrate body having a front surface and a back surface, and a lower ceramic layer in the substrate body. It includes a notch formed on a side surface of the layer, a notch conductor formed in the notch, and an insulating part formed to cover at least the upper end of the notch conductor.

  According to this, in the multi-piece wiring board for obtaining the wiring board, the part where the plating solution is poorly circulated is covered with the insulating part by the insulating part covering the upper end part of the notched conductor. Therefore, the metal plating layer is not formed, and the metal plating layer is easily formed in other portions. For this reason, a metal plating layer made of, for example, Au and having a required thickness is formed on the entire surface of the notch conductor except the upper end covered with the insulating portion. As a result, when mounting the wiring board obtained by cutting and dividing the multi-piece wiring board on the motherboard, between the external terminal of the motherboard and the notch conductor is firmly made by solder having high wettability. Can be joined. Therefore, it is possible to stably obtain conduction between the internal wiring of the wiring board and the mother board. The solder refers to a low melting point metal or alloy.

Each ceramic layer forming the substrate body is made of, for example, a ceramic mainly composed of alumina, or a glass-ceramic that is a kind of low-temperature firing.
Moreover, the upper layer side and lower layer side ceramic layers include not only a single layer but also a form in which a plurality of ceramic layers are laminated.
Further, a cavity having a through hole provided in the upper ceramic layer as a side surface may be opened on the surface of the substrate body, and an electronic component, a light emitting element, or the like is mounted on the bottom surface of the cavity.
Further, the notch and the notch conductor may be formed at a corner portion between adjacent side surfaces in addition to an intermediate position between the side surfaces of the lower ceramic layer.
Furthermore, the notch conductor is electrically connected to the internal wiring of the wiring board, and can also be connected to an electronic component or a light emitting element mounted on the surface of the board body or a cavity opened on the surface via the internal wiring. It is said that.

The present invention also includes a wiring board (Claim 2) in which the insulating portion has a curved surface or a tapered surface in contact with the notch conductor. In addition, the said taper surface includes the form which consists of a combination of a some inclined surface other than consisting of one inclined surface.
Furthermore, the present invention includes a wiring board (Claim 3) in which the insulating portion forms an obtuse angle with the notch conductor. The range of the obtuse angle is from over 90 degrees to 150 degrees. The range over 150 degrees is excluded because it approaches the plane. In the case of the insulating part having the curved surface, the obtuse angle is formed between the tangent line that is in the vicinity of the center of the curved surface and the surface of the notch conductor in a vertical cross section perpendicular to the surface of the substrate body.
According to these, the said insulation part which covers the upper end part of a notch part conductor has the curved surface or taper surface which touches this notch part conductor, or has made an obtuse angle between notch part conductors. . As a result, in the multi-piece wiring board for obtaining the wiring board, the portion where the plating solution is poorly circulated is covered with the insulating portion, so that the metal plating layer is not formed, but is covered with the insulating portion. A metal plating layer is easily formed in a portion where there is no. For this reason, a metal plating layer made of, for example, Au and having a required thickness is formed on the entire surface of the cutout conductor excluding the upper end covered with the insulating portion. Therefore, when the wiring board is mounted on the mother board, the external terminal of the mother board and the notch conductor can be firmly joined by solder having high wettability.

  On the other hand, the multi-piece wiring board of the present invention (Claim 4) is configured by laminating an upper ceramic layer and a lower ceramic layer, and a product region in which a plurality of products are arranged vertically and horizontally in a plan view. And a base substrate having an ear portion surrounding the product region, and a cutting plane that is a boundary between products in the product region in the lower ceramic layer and a boundary between the product region and the ear portion of the base substrate. A through hole that intersects and penetrates the ceramic layer on the lower layer side, an inner wall conductor formed on the inner wall of the through hole, and an insulating part formed to cover at least the upper end of the inner wall conductor, It is characterized by that.

According to this, when the multi-layered wiring board is immersed in the plating solution by the insulating portion covering the upper end portion of the inner wall conductor, the portion where the circulation of the plating solution is bad is covered with the insulating portion. Therefore, while the metal plating layer is not formed, the plating solution is smoothly circulated in portions other than the insulating portion. As a result, a metal plating layer made of, for example, Au and having a required thickness is formed on the entire surface of the inner wall conductor excluding the upper end covered with the insulating portion. For this reason, the notched conductor for each of the plurality of wiring boards obtained by cutting and dividing the multi-cavity wiring board is also formed with the metal plating layer except for its upper end. Therefore, when the divided wiring board is mounted on the mother board, the external terminals of the mother board and the notch conductor can be firmly bonded via the solder.
The inner wall conductor formed along the inner wall of the through hole has a substantially cylindrical shape that is substantially similar to the inner wall of the through hole.

The present invention also includes a multi-piece wiring board (Claim 5) in which the insulating portion has a curved surface or a tapered surface in contact with the inner wall conductor.
Furthermore, the present invention includes a multi-piece wiring board (Claim 6) in which the insulating portion forms an obtuse angle with the inner wall conductor.
The obtuse angle is in the range from over 90 degrees to 150 degrees.
According to these, the insulating portion covering the upper end portion of the inner wall conductor has a curved surface or a tapered surface in contact with the inner wall conductor, or forms an obtuse angle with the inner wall conductor. For this reason, when the multi-piece wiring board is immersed in a plating solution, the poorly circulated portion of the plating solution is covered with the insulating portion, so that the metal plating layer is not formed but is covered with the insulating portion. The plating solution circulates well in the parts that are not present. As a result, a metal plating layer made of, for example, Au and having a required thickness is formed on the entire surface of the inner wall conductor excluding the upper end. Therefore, the cutout conductors for each of the plurality of wiring boards obtained by cutting and dividing the multi-piece wiring board and the external terminals of the mother board can be firmly bonded via the solder.

  Further, the method for manufacturing a multi-piece wiring board according to the present invention (Claim 7) is arranged vertically and horizontally in the step of applying a solvent to the back surface of the upper green sheet and the product area of the lower green sheet. A plurality of sets of through-holes that intersect the planned cutting plane that is a boundary between a plurality of products and a boundary between a product region and an ear part surrounding the product region, and that penetrate through the green sheet on the lower layer side, along the inner wall of the through-hole A step of forming an inner wall conductor, and a step of laminating and pressing the upper green sheet and the lower green sheet.

According to this, a base substrate having a product region and an ear portion surrounding the product region is formed by laminating and pressing the upper-layer side green sheet and the lower-layer side green sheet, and A plurality of sets of through-holes and inner wall conductors that penetrate the lower-layer side green sheet are formed at the intersecting positions. In addition, at least the upper end portion of the inner wall conductor is covered with an insulating portion in which a part of the back surface side in which the solvent has permeated in the upper layer side green sheet extends to the inside of the inner wall conductor. Accordingly, when forming a Ni and Au plating layer, for example, on the inner wall conductor later, the portion with poor circulation of the plating solution is covered with the insulating portion, so that the metal plating layer is not formed. Since the plating solution easily circulates over the entire surface of the inner wall conductor, a metal plating layer having a required thickness can be formed.
In addition, it is possible to form a curved surface or a tapered surface in the insulating part by adjusting the kind of the solvent and the pressure bonding method.

  In other words, the present invention includes a step of firing the multi-cavity wiring board, a step of forming a metal plating layer on the inner wall conductor of the fired multi-cavity wiring board, and then a multi-cavity wiring board. Including a step of cutting along a planned cutting plane that is a boundary between a plurality of products arranged vertically and horizontally in the product region and a boundary between the product region and an ear portion surrounding the product region. Can be. In this case, a plurality of the wiring boards can be efficiently and reliably manufactured.

In the following, the best mode for carrying out the present invention will be described.
FIG. 1 is a vertical sectional view showing a wiring board p1 according to one embodiment of the present invention.
As shown in FIG. 1, the wiring board p <b> 1 is substantially square in plan view and has a substrate body 1 having a front surface 2 and a back surface 3, a cavity 14 opened in the front surface 2 of the substrate body 1, and a back surface 3 of the substrate body 1. And a plurality of cutout portions 5 formed over the side surface 4 and a plurality of cutout conductors 6 formed in each cutout portion 5.
As shown in FIG. 1, the substrate body 1 is formed by integrally laminating upper ceramic layers c2 and c3 mainly made of alumina and a lower ceramic layer c1. In the upper ceramic layer c3, the side surface 16 of the cavity 14 is inclined so as to spread toward the surface 2 side of the substrate body 1, and penetrates in a substantially conical shape. The bottom surface 15 of the cavity 14 that is the surface of c2 is exposed in a circular plan view.

  A metal layer 17 made of W or Mo is formed on the side surface 16 of the cavity 14, and an Ag plating layer for light reflection (none of which is shown) is formed on the surface of the metal layer 17 through, for example, an underlying Ni plating layer. It is formed on the surface layer. A pair of pads 18 made of W or the like is formed on the bottom surface 15 of the cavity 14, and a light emitting diode (light emitting element) C indicated by a one-dot chain line in FIG. The light-emitting diode C is connected to a pair of pads 18 via a bonding wire (not shown), and light emitted from the light-emitting diode C is reflected on an Ag plating layer that covers the surface layer of the metal layer 17 to form a wiring board. Radiated outside p1.

As shown in FIG. 1, an internal wiring 20 made of W or the like and having a predetermined pattern is formed between lower and upper ceramic layers c1 and c2 forming the substrate body 1. A plurality of external terminals 19 made of W or the like are formed on the back surface 3 of the substrate body 1. The pad 18 and the internal wiring 20 are connected by a via conductor 21 made of W or the like, and the internal wiring 20 and the external terminal 19 are connected by a via conductor 22 similar to the above.
The internal wiring 20 and the cutout conductor 6 are also connected. A via conductor 21 (not shown) connects the metal layer 17 and the internal wiring 20.

As shown in FIGS. 1 and 2, a cutout portion 5 having a substantially semicircular shape in plan view is formed on the side surface 4 of the lower ceramic layer c <b> 1 in the substrate body 1, and a flat surface is formed on the inner peripheral surface of the cutout portion 5. A cutout conductor 6 having a substantially semicircular cross section as viewed is formed.
As shown in the partial enlarged cross-sectional view of FIG. 2 and the partial horizontal cross-sectional view taken along the line XX in FIG. 2, the notch conductor 6 is a semi-ring-shaped horizontal extending between the ceramic layers c1 and c2. A piece 6a and a semi-ring-shaped horizontal piece 6b extending on the back surface 3 of the substrate body 1 are provided at the upper and lower ends. The cutout conductor 6 has an upper end portion 6c covered with an insulating portion 10 in which a part of the upper ceramic layer c2 extends on the back surface 3 side of the substrate body 1.

As shown in FIG. 2, the insulating portion 10 has a curved surface 11 having a recessed shape. In a vertical cross section perpendicular to the surface 2 of the substrate body 1, the angle between the tangent line s in contact with the vicinity of the center of the curved surface 11 and the surface of the notch conductor 6 is an obtuse angle θ of about 130 degrees.
As shown in FIGS. 1 and 2, the entire surface of the notch conductor 6 except for the upper end 6c and the horizontal piece 6a covered with the insulating part 10 is a Ni plating layer having a thickness of about 1 to 15 μm as a base. And a metal plating layer 8 composed of an Au plating layer having a thickness of about 0.1 to 5.0 μm on the surface layer.

3 is a vertical sectional view showing a wiring board p2 of a different form, FIG. 4 is a partial enlarged sectional view in FIG. 3, and FIG. 5 is a partial sectional view taken along the line YY in FIG. FIG.
As shown in FIG. 3, the wiring board p2 also includes the same substrate body 1 composed of the lower ceramic layer c1 and the upper ceramic layers c2 and c3, the cavity 14 composed of the bottom surface 15 and the side surface 16, the metal layer 17, A pad 18, an external terminal 19, an internal wiring 20, via conductors 21 and 22, a notch 5 formed across the back surface 3 and the side surface 4 of the substrate body 1, and a notch conductor 6 formed in the notch 5; It has.
As shown in FIG. 4 and FIG. 5, the side surface 4 of the lower layer ceramic layer c <b> 1 in the substrate body 1 is formed with a substantially semicircular cutout portion 5 in plan view, and a flat surface is formed on the inner peripheral surface of the cutout portion 5. A cutout conductor 6 having a substantially semicircular cross section as viewed is formed.

The notch conductor 6 has semi-ring-shaped horizontal pieces 6a and 6b at the upper and lower ends thereof, and the upper end portion 6c of the upper ceramic layer c2 extends partially toward the back surface 3 of the substrate body 1. Covered with the insulating part 12.
As shown in FIG. 4, the insulating portion 12 has a tapered surface 13 that is inclined so as to spread from the front surface 2 side to the back surface 3 side of the substrate body 1 in the insulating portion 12. In a vertical cross section perpendicular to the surface 2 of the substrate body 1, the angle between the tapered surface 13 and the surface of the notch conductor 6 is an obtuse angle θ of about 130 degrees.
As shown in FIG. 4, the entire surface of the notch conductor 6 except for the upper end 6c and the horizontal piece 6a covered with the insulating portion 12 is plated with a metal plating composed of a base Ni plating layer and a surface Au plating layer. The layer 8 is formed with the same thickness as described above.

  According to the wiring boards p1 and p2 as described above, the notched conductor 6 formed on the side surface 4 of the ceramic layer c1 on the lower layer side of the substrate body 1 is formed by the insulating parts 10 and 12 covering the upper end part 6c. In the multi-piece wiring board for obtaining the wiring boards p1 and p2, the portions where the plating solution is poorly circulated are covered with the insulating portions 10 and 12, so that the metal plating layer 8 is not formed. On the other hand, the entire surface of the notch conductor 6 except for the upper end portion 6c that is not covered with the insulating portions 10 and 12 and in which the plating solution easily circulates, is plated with Au having a required thickness on the surface layer. A metal plating layer 8 having a layer is formed. Therefore, when the wiring boards p1 and p2 obtained by cutting and dividing the multi-piece wiring board are mounted on the mother board, the Ni plating layer as the base of the metal plating layer 8 is difficult to diffuse and the solder easily wets and spreads. The external terminal of the mother board and the notch conductor 6 can be firmly joined via solder.

Further, by connecting the plurality of notch conductors 6 to a plurality of (for example, two) circuits that are electrically independent, the surface of the pad 18 and the external terminal 19 is connected to the surface of the pad 18 and the external terminal 19 via one circuit. The Ni plating layer and the surface Au plating layer are formed, and the underlying Ni plating layer and the light reflecting Ag are applied to the metal layer 17 formed on the side surface 16 of the cavity 14 via the other circuit. A plating layer can also be formed.
The notch 5 and the notch conductor 6 may be formed at each corner between the side surfaces 4 and 4 adjacent to each other in the ceramic layer c1 on the lower layer side of the substrate body 1. In such a corner portion, the notch portion 5 and the notch portion conductor 6 have an arc shape or a cross section that is a substantially circular quarter in plan view.

FIG. 6 is a plan view showing a multi-piece wiring board K1 for obtaining a plurality of wiring boards p1, FIG. 7 is a bottom view of the multi-piece wiring board K1, and FIG. It is a vertical sectional view along the arrow of the ZZ line in the inside.
As shown in FIGS. 6 to 8, the multi-cavity wiring board K1 is formed by laminating upper ceramic layers c2 and c3 mainly made of alumina and a lower ceramic layer c1. A base substrate 31 having a product region P in which individual (plural) wiring substrates (products) p1 are arranged vertically and horizontally and a square frame-shaped ear portion m surrounding the product region P is provided. 6 and 7, broken lines indicating boundaries between the wiring boards p1 and p1 adjacent to each other and between the wiring boards p1 and the product region P are virtual cutting planes f. The front surface 32 and the back surface 33 are used in common for the base substrate 31, the product region P, the wiring substrate p1, and the ear portion m. Furthermore, the ceramic layers c1 to c3 are of a large plate size.
In the lower ceramic layer c1 constituting the base substrate 31, a plurality of through holes 25 intersecting the planned cutting line f and penetrating the ceramic layer c1 are provided on each side surface (4) of each wiring board p1. A substantially cylindrical inner wall conductor 26 made of W or the like is formed along the inner wall of each through hole 25.

As shown in FIGS. 6 to 8, each wiring board p <b> 1 located in the product region P includes a cavity 14 having the same bottom surface 15 and side surface 16, a metal layer 17 on the side surface 16, and a bottom surface of the cavity 14. 15, a plurality of external terminals 19 positioned on the back surface 33 of the base substrate 31, internal wiring 20 positioned between the ceramic layers c1 and c2, and via conductors 21 and 22 penetrating the ceramic layers c1 and c2, respectively. Is formed.
The base substrate 31 has a substantially square outer shape in plan view, and each wiring substrate p1 also has a square outer shape in plan view. The bottom surface 15 of each cavity 14 opened to the surface 32 of the base substrate 31 has The side view 16 of the cavity 14 has a substantially conical shape extending from the bottom surface 15 toward the surface 32.

As shown in the enlarged sectional view of FIG. 9, an inner wall conductor 26 having a substantially cylindrical shape is formed along the inner wall of the through hole 25 having a substantially circular cross section passing through the lower ceramic layer c <b> 1 constituting the base substrate 31. Is formed. The inner wall conductor 26 has a ring-shaped horizontal piece 26a extending between the ceramic layers c1 and c2 and a ring-shaped horizontal piece 26b extending on the back surface 33 of the base substrate 31 at the upper and lower ends. The inner wall conductor 26 has an upper end portion 26c covered with an insulating portion 40 that extends from the back surface 33 side of the base substrate 31 with a part of the ceramic material forming the upper ceramic layer c2.
The insulating portion 40 has a substantially hemispherical curved surface 41 that is recessed on the back surface 33 side of the base substrate 31 and is in contact with the inner wall conductor 26. In FIG. 9, which is a vertical cross section orthogonal to the surface 32 of the base substrate 31, the angle between the tangent line s that contacts the vicinity of the center of the curved surface 41 of the insulating portion 40 and the surface of the inner wall conductor 26 is about 140 degrees. The obtuse angle θ.

As shown in FIG. 9, the entire surface of the cutout conductor 26 excluding the upper end portion 26c and the horizontal piece 26a covered with the insulating portion 40 is plated with a metal made of an underlying Ni plating layer and a surface Au plating layer. The layer 28 is formed with the same thickness as the metal plating layer 8.
FIG. 10 is a vertical sectional view similar to FIG. 8 showing a different multi-piece wiring board K2, and FIG. 11 is a partially enlarged sectional view of FIG.
As shown in FIGS. 10 and 11, the multi-piece wiring board K2 is also composed of lower and upper ceramic layers c1 to c3, and includes a product region P in which a plurality of wiring boards p2 are arranged and an ear portion m surrounding the product area P. A base substrate 31 similar to that described above is provided. In addition, the same cavity 14, metal layer 17, pair of pads 18, a plurality of external terminals 19, internal wirings 20, and via conductors 21 and 22 are formed in each wiring board p <b> 2. The front surface 32 and the back surface 33 are used in common for the base substrate 31, the product region P, the wiring substrate p2, and the ear portion m.

As shown in FIG. 11, an inner wall conductor 26 is formed along the inner wall of the through-hole 25 that penetrates the lower ceramic layer c1, and the inner wall conductor 26 has the same horizontal piece 26a and horizontal piece 26b as described above. At the top and bottom. The inner wall conductor 26 has an upper end portion 26c covered with an insulating portion 42 that extends partly on the upper surface side of the ceramic layer c2 on the back surface 33 side of the base substrate 31.
The insulating portion 42 has a substantially conical tapered surface 43 that is inclined so as to spread from the front surface 32 side to the rear surface 33 side of the base substrate 31 and is in contact with the inner wall conductor 26. In FIG. 11, which is a vertical sectional view orthogonal to the surface 32 of the base substrate 31, the angle between the tapered surface 43 of the insulating portion 42 and the surface of the inner wall conductor 26 is an obtuse angle θ of about 130 degrees.
As shown in FIG. 11, the entire surface of the cutout conductor 26 except for the upper end portion 26c and the horizontal piece 26a covered with the insulating portion 42 is plated with a metal composed of a base Ni plating layer and a surface Au plating layer. The layer 28 is formed with the same thickness as described above.

According to the multi-piece wiring boards K1 and K2 as described above, the upper end portion 26c of the inner wall conductor 26 is covered with the insulating portions 40 and 42 having the curved surface 41 or the tapered surface 43. When the wiring boards K1 and K2 are immersed in the plating solution, the plating solution does not circulate and the metal plating layer is not formed. On the other hand, since the plating solution circulates smoothly in the portions not covered by the insulating portions 40 and 42, the Ni plating layer and Au are formed on the entire surface of the inner wall conductor 26 except the upper end portion 26c and the horizontal piece 26a. A metal plating layer 28 made of a plating layer and having a required thickness is formed. Therefore, the cutout conductor 6 for each of the plurality of wiring boards p1 and p2 obtained by cutting and dividing the multi-cavity wiring boards K1 and K2 along the planned cutting surface f is also the upper end portion 6c. The metal plating layer 8 is formed except for. Therefore, when the wiring boards p1 and p2 are mounted on the mother board, the external terminals of the mother board and the notch conductor 6 can be firmly joined via the solder.
The through hole 25 and the inner wall conductor 26 may be formed at a position where a plurality of scheduled cutting surfaces f intersect in the bottom view of FIG. In the multi-piece wiring boards K1 and K2 having such a configuration, by dividing this, the cutout conductor 6 is formed in the corner portion between the adjacent side surfaces 4 and 4 in the ceramic layer c1 on the lower layer side of the substrate body 1. It is formed.

The multi-cavity wiring boards K1, K2 and the wiring boards p1, p2 were manufactured as follows. In the following, the length in the left-right direction of each drawing is slightly shortened for the convenience of drawing.
A ceramic slurry was prepared by mixing raw materials composed of alumina powder particles, a resin binder, a plasticizer, a solvent, and the like in advance. The ceramic slurry was subjected to a doctor blade method to form three green sheets s1 to s3 having a thickness of about 300 μm. As illustrated in FIG. 12, the green sheets s1 to s3 are square in a product area P in which a plurality of wiring boards (products) p forming the wiring boards p1 and p2 are arranged vertically and horizontally and in a plan view surrounding the product area P. It is of a large plate size that is used for taking a large number of pieces having a frame-shaped ear portion m and a planned cutting surface (virtual surface) f that is a boundary between them.
First, as shown in the upper part of FIG. 13, with respect to the green sheet s3 of the uppermost layer (upper layer side), a required clearance is provided so that the back side has a small diameter and the front side has a large diameter between the front and back surfaces. A substantially conical through-hole 17a was formed in the center of each wiring board p by a shearing action between the punch and the die receiving hole.

Further, as shown in the middle of FIG. 13, a plurality of via holes h penetrating between the front surface and the back surface of each of the plurality of wiring boards p are formed on the middle layer (upper layer side) green sheet s <b> 2. It was formed by punching with a receiving hole. In addition, a solvent w made of n-butyl phthalate, castor oil, n-butyl alcohol, or the like was previously applied to the back surface side of the green sheet s2 so as to penetrate with a predetermined thickness.
Further, as shown in the lower part of FIG. 13, a plurality of via holes h penetrating between the front surface and the back surface of each of the plurality of wiring boards p are formed in the lower layer side green sheet s 1, and each cutting scheduled surface f is also formed. Through holes 25 along the thickness direction were formed at the predetermined positions by the same punching process.

Next, as shown in the upper part of FIG. 14, a metal mask (not shown) and a squeegee are used for the inner peripheral surface of each through-hole 17a of the uppermost (upper layer side) green sheet s3, and from the opposite surface or back surface. As the suction state, a conductive paste containing W or Mo powder was printed with a predetermined thickness, and the metal layer 17 was formed on each of them.
Further, as shown in the middle of FIG. 14, the same conductive paste as described above is filled into each via hole h of the green sheet s2 of the middle layer (upper layer side) using the same metal mask and squeegee as described above. The via conductor 21 was formed in each.
Further, as shown in the lower part of FIG. 14, via conductors 21 similar to the above were also formed in each via hole h of the green sheet s 1 on the lower layer side. In addition, using the metal mask and the squeegee and sucking from the opposite surface or back surface, apply the same conductive paste as above to each inner wall of each through hole 25 in the green sheet s1 on the lower layer side, A substantially cylindrical inner wall conductor 26 was formed.

Next, as shown in the middle of FIG. 15, the same conductive paste as described above is screen-printed on the surface of the middle layer (upper layer side) green sheet s <b> 2 so as to be connected to the upper end of each via conductor 21. A pair of pads 18 was formed for each product portion p.
Further, as shown in the lower part of FIG. 15, the same conductive paste as described above is screen-printed on the front and back surfaces of the green sheet s1 on the lower layer side so as to be connected to the upper end or the lower end of each via conductor 22. A predetermined pattern of internal wiring 20 and a plurality of external terminals 16 were formed.
Then, as indicated by the arrows in FIG. 15, the upper-layer side green sheets s2 and s3 were laminated on the lower-layer side green sheet s1 in sequence or simultaneously and pressed.

  As a result, as shown in FIG. 16, the green substrates s1 to s3 are laminated to form a base substrate 31 having a front surface 32 and a rear surface 33, a plurality of wiring substrates p arranged vertically and horizontally in the product region P, and A green sheet laminate S1 having an opening in the front surface 32 of the wiring board p and a cavity 14 composed of a bottom surface 15 and a side surface 16 was formed. At this time, a ceramic material mainly made of alumina softened by the solvent w in the green sheet s2 above the inner wall conductor 26 of each through hole 25 is partially a plurality of inner walls due to the pressure accompanying the pressure bonding. It extended (extends) to the inside of the conductor 26 to cover the upper end portion 26c of each inner wall conductor 26. As a result, in the cross section perpendicular to the surface 32 of the base body 31, an insulating portion 40 having a substantially hemispherical curved surface 41 that is recessed toward the back surface 33 side of the base body 31 is formed at the upper portion of each through hole 25. It was done.

Further, by adjusting the penetration depth of the solvent w with respect to the upper layer side green sheet s2 and the pressure at the time of pressure bonding, a part of the ceramic material forming the green sheet s2 is extended inside each inner wall conductor 26, The upper end portion 26c of the inner wall conductor 26 is covered.
As a result, as shown in FIG. 17, a green sheet laminate S2 including the base substrate 31 similar to the above is formed, and is recessed toward the back surface 33 side of the base body 31 at the top of each through hole 25. However, the insulating buried portion 42 having the substantially conical tapered surface 43 could be formed.

Further, the green sheet laminates S1 and S2 were fired at a required temperature range.
Next, the base substrate 31 in which the green sheets s1 to s3 are fired to become the lower and upper ceramic layers c1 to c3 is dipped in a plating tank (not shown), and a plurality of inner wall conductors 26 are plated with electrode bars. After the electrolytic Ni plating was performed in the state of contact, the electrolytic Au plating was performed in the same state as described above by dipping in another plating tank.
At this time, in the inner wall conductor 26 for each base substrate 31 that has been baked, the portion where the plating solution is poorly circulated is covered with the insulating portions 40 and 42 having the curved surface 41 or the tapered surface 43 covering the upper end portion 26c. Therefore, the metal plating layer 28 was not formed. On the other hand, the plating solutions were easily circulated on the surface of each inner wall conductor 26 other than the upper end portion 26c not covered with the insulating portions 40 and 42.
As a result, a metal plating layer 28 composed of a Ni plating layer and an Au plating layer having a required thickness was formed on the surface of each inner wall conductor 26. At the same time, the same metal plating layer (not shown) was also formed on the surfaces of the pads 18 located on the bottom surface 15 of the cavity 14 and the external terminals 19 located on the back surface 33 of the base substrate 31.

Subsequently, after performing electrolytic Ni plating in a state where the electrode rod for plating is in contact with the inner wall conductor 26 different from the above, the electrolytic Ag plating is immersed in another plating tank and in the same manner as described above. went. As a result, an Ag plating layer for light reflection (none of which is shown) is required on the surface layer side of the surface of the fired metal layer 17 formed on the side surface 16 of each cavity 14 through the underlying Ni plating. It was able to be formed with a thickness.
As a result, the multi-cavity wiring board K1 shown in FIGS. 6 to 9 or the multi-cavity wiring board K2 shown in FIGS. 10 and 11 could be manufactured.
According to the manufacturing method of the multi-piece wiring boards K1 and K2 as described above, the Ni plating layer having a required thickness and the surface of the inner wall conductor 26 formed for each through hole 25 of the ceramic layer c1 on the lower layer side The multi-piece wiring boards K1 and K2 on which the metal plating layer 28 made of an Au plating layer was formed could be reliably formed.

Then, the multi-piece wiring boards K1 and K2 were cut in the thickness direction of each base board 31 by using a blade (not shown) along the planned cutting plane f.
As a result, as shown in FIG. 18, the substrate body 1 composed of the lower and upper ceramic layers c1 to c3, the cutout portion 5 formed on the side surface 4 of the lower ceramic layer c1, and the cutout portion 5 are formed. A plurality of the same wiring boards p1 including the notched conductor 6 and the insulating part 10 covering the upper end 6c of the notched conductor 6 and having the curved surface 11 could be manufactured.

Alternatively, as shown in FIG. 19, the substrate body 1, the notch portion 5, the notch portion conductor 6, and the insulating portion 12 that covers the upper end portion 6 c of the notch portion conductor 6 and has a tapered surface 13 as described above. A plurality of wiring boards p2 could be manufactured.
According to the manufacturing method of the wiring boards p1 and p2 as described above, a required thickness is provided on the surface of the notch conductor 6 formed for each of the plurality of notches 5 formed on the side surface 4 of the lower ceramic layer c1. The wiring boards p1 and p2 on which the metal plating layer 8 composed of the Ni plating layer and the Au plating layer having the above was formed could be efficiently and reliably formed.

The present invention is not limited to the embodiments described above.
The ceramic layer and the green sheet are not limited to alumina, but may be made of a ceramic material such as mullite or aluminum nitride, or may be made of a glass-ceramic material that is a kind of low-temperature fired ceramic.
The upper ceramic layer may be formed of one layer or three or more layers, or the lower ceramic layer may be formed of two or more layers.
Further, the notch and the notch conductor may be formed both in the middle of each side surface of the lower layer side base substrate and in each corner between adjacent side surfaces. Accordingly, in the multi-piece wiring board, the through hole and the inner wall conductor may be formed at a position where a plurality of scheduled cutting surfaces intersect with each other as well as an intermediate position between each scheduled cutting surface.

Further, the cavity of the wiring board may have an oval shape in a plan view and a substantially conical shape on a side surface, or an oval shape in a bottom view in a plan view, and a substantially elliptic cone shape on a side surface.
In addition, the wiring board has a flat surface without the cavity on the surface of the substrate body, and an electronic component such as an IC chip can be conducted to a pad formed on the flat surface, and the electronic component is mounted on the surface. It is good also as a form to do.
Alternatively, the wiring board is configured to have a cavity having an opening on the surface of the substrate body and having a rectangular (square or rectangular) bottom surface and four side surfaces standing vertically from the periphery of the cavity. The electronic component may be mounted on the bottom surface.

The vertical sectional view showing the wiring board of one form in the present invention. The partial expanded sectional view of the said wiring board. The vertical sectional view which shows the wiring board of a different form. The partial expanded sectional view of the said wiring board. Sectional drawing along the arrow of the YY line in FIG. The top view which shows the multi-piece substrate of one form in this invention. The bottom view of the said multi-piece substrate. FIG. 8 is a vertical sectional view taken along the line ZZ in FIG. 6 and FIG. 7. The partial expanded sectional view in FIG. The vertical sectional view which shows the multi-piece substrate of a different form. The elements on larger scale in FIG. Schematic which shows the manufacturing process of the said multi-piece substrate. Schematic which shows the manufacturing process following FIG. Schematic which shows the manufacturing process following FIG. Schematic which shows the manufacturing process following FIG. Schematic which shows the green sheet laminated body obtained by each above process. Schematic which shows the green sheet laminated body of a different form. Schematic which shows the said wiring board which divided | segmented the said multi-piece substrate. Schematic which shows the said wiring board of the different form divided | segmented similarly to the above.

Explanation of symbols

1 …………………………… Board body 2, 32 …………………… Front side 3,33 …………………… Back side 4 …………………………… Side 5 …………………………… Notch 6 …………………………… Notch conductor 6c, 26c ……………… Upper end 10, 12, 40, 42… Insulation Part 11, 41 ............... Curved surface 13, 43 ............... Tapered surface 25 ………………………… Through hole 26 ………………………… Inner wall Conductor 31 ………………………… Base substrate p, p1, p2 …………… Wiring substrate (product)
K1, K2 ………………… Multi-layer wiring board c1 ………………………… Ceramic layer c2, c3 of the lower layer ………………… Ceramic layer P of the upper layer P …… …………………… Product area m ……………………………… Ear part f …………………………… Planned cutting plane θ ………………………… … Obtuse angle s1 ………………………… Lower side green sheet s2, s3 ………………… Upper side green sheet

Claims (7)

A substrate body composed of a ceramic layer on the upper layer side and a ceramic layer on the lower layer side, and having a front surface and a back surface;
A notch formed on the side surface of the lower ceramic layer in the substrate body and a notch conductor formed in the notch, and
An insulating part formed so as to cover at least the upper end part of the notch conductor,
A wiring board characterized by that. The insulating portion has a curved surface or a tapered surface in contact with the notch conductor.
The wiring board according to claim 1. The insulating part forms an obtuse angle with the notch conductor,
The wiring board according to claim 1 or 2, wherein A base substrate that is formed by laminating an upper ceramic layer and a lower ceramic layer, and has a product region in which a plurality of products are arranged vertically and horizontally in plan view, and an ear that surrounds the product region;
A through hole passing through the lower ceramic layer and intersecting a planned cutting surface that is a boundary between products in the product region and a boundary between the product region and the ear portion in the lower ceramic layer of the base substrate; ,
An inner wall conductor formed on the inner wall of the through hole;
An insulating part formed to cover at least the upper end part of the inner wall conductor,
A multi-piece wiring board characterized by that. The insulating portion has a curved surface or a tapered surface in contact with the inner wall conductor.
The multi-piece wiring board according to claim 4, wherein The insulating part forms an obtuse angle with the inner wall conductor,
6. The multi-piece wiring board according to claim 4, wherein the multi-piece wiring board is provided. Applying a solvent to the back side of the upper green sheet;
Crossing the boundary between a plurality of products arranged vertically and horizontally in the product region of the lower layer side green sheet and the planned cutting surface that is the boundary between the product region and the surrounding ears, and the lower side green sheet Forming a plurality of sets of through-holes penetrating through and inner wall conductors along the inner walls of the through-holes;
Laminating and pressing the upper layer side green sheet and the lower layer side green sheet,
A method of manufacturing a multi-cavity wiring board characterized by the above.

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