JP2019186441A - Wiring board and manufacturing method of the same - Google Patents

Abstract

To provide a wiring board in which a metal layer hardly generating voids in an inner part is covered on the front surface side of a conductive layer formed on the bottom surface or side surface of a concave part opened in at least one of the front and rear surfaces of a substrate body made of a plurality of insulation layers, and a manufacturing method of the same.SOLUTION: Each of wiring boards 1a and 1b, includes: a substrate main body 2 which is formed by laminating a plurality of ceramic layers (insulation layers) c1 to c4, and has a front surface 3 and a rear surface 4 which are opposite each other; concave parts 5 and 8 which are opened to one of the front surface 3 and the rear surface 4 of the substrate main body 2, and have bottom surfaces 6 and 10 and side surfaces 7 and 9; conductive layers 15 and 19 which are formed on at least one of the bottom surfaces 6 and 10 and the side surfaces 7 and 9 structuring the concave parts 5 and 8; and convex strip parts 11 to 14 formed by a part of the insulation layers c1 to c4 while being projected to a thickness direction of the substrate main body 2 or a direction orthogonal to the thickness direction along a corner part of the bottom surfaces 6 and 10 and the side surfaces 7 and 9 structuring the concave parts 5 and 8.SELECTED DRAWING: Figure 1

Description

  The present invention provides a wiring board in which a metal layer by metal plating is firmly and accurately coated on a surface of a conductor layer formed on at least one of a bottom surface and a side surface of a recess opening on at least one of a front surface and a back surface of a substrate body, and It relates to the manufacturing method.

For example, in a ceramic body in which a plurality of ceramic sheets are laminated, the above ceramic body including a concave portion provided with a concave portion whose opening diameter increases stepwise toward the outer side and a metallized metal layer is deposited on the inner surface. An electrolytic plating method has been proposed in which a plating metal layer is deposited on the outer surface of the metallized metal layer by immersing in a plating solution and performing electrolytic plating (for example, see Patent Document 1).
According to the electrolytic plating method, the plating metal layer can be prevented from generating any battery action or crevice corrosion action, and unnecessary discoloration or elution can be prevented from occurring in the plating metal layer.

However, in the electrolytic plating method, through holes having different inner diameters are formed in advance for each of the plurality of ceramic sheets constituting the ceramic body, and the plurality of ceramic sheets are laminated so that the through holes are concentric. And since the said recessed part is formed, in order to provide this recessed part, a complicated manufacturing process is needed.
In addition, if the corner between the ceiling or bottom surface constituting the recess and the inner wall is a right angle, it is difficult for the plating solution to flow into the vicinity of the corner. Since (bubbles) are likely to occur, there is a problem that the generation of such voids may not be effectively prevented.

JP-A-6-33297 (pages 1 to 5, FIGS. 1 and 2)

Problems to be solved by the invention and effects of the invention

  The present invention solves the problems described in the background art, and includes a substrate body having a plurality of insulating layers stacked and having a front surface and a back surface that face each other, and a bottom surface of a recess that opens to at least one of the front surface and the back surface. It is an object of the present invention to provide a wiring board in which a metal layer that suppresses the generation of voids is coated on the surface of a conductor layer formed on a side surface with high accuracy and a manufacturing method that can easily manufacture the wiring board.

In order to solve the above problems, the present invention comprises a part of any one of the insulating layers along the corner between the bottom surface and the side surface of the recess, and along the thickness direction or planar direction of the substrate body. The idea is to provide a protruding ridge that protrudes.
That is, the wiring board of the present invention (Claim 1) is formed by laminating a plurality of insulating layers, and has an opening on at least one of the front surface and the back surface of the substrate body having the front surface and the back surface facing each other, and A wiring board having a concave portion having a bottom surface and a side surface, and a conductor layer formed on at least one of the bottom surface and the side surface constituting the concave portion, at a corner portion between the bottom surface and the side surface constituting the concave portion And having a ridge that protrudes in the thickness direction of the substrate body or in a direction perpendicular to the thickness direction and is formed of a part of the insulating layer.

According to the wiring board, the following effects (1) to (3) can be obtained.
(1) Projecting along the thickness direction of the substrate body or the direction perpendicular to the thickness direction along the corners of the bottom surface and the side surface constituting the recess, and a part of any of the insulating layers Therefore, when a part of the conductor layer is formed by metal plating, the protrusions promote the circulation of the plating solution in the vicinity of the corners in the recess. Therefore, even when the metal layer (part of the conductor layer) formed by metal plating in the plating process at the time of manufacture is near the corner, the metal layer does not easily contain voids and is firmly and accurately with a desired thickness. It is covered.
(2) Since protrusions are formed at the corners, it is difficult for moisture or outside air from the outside to enter and contact the metallized layer, which is a part of the conductor layer, in the vicinity of the corners. Therefore, the reliability regarding the electrical characteristics of the conductor layer can be improved.
(3) Since the area for laminating the insulating layer with the protruding ridges protruding and another insulating layer laminated adjacent to the insulating layer increases, an interlayer shift between these adjacent insulating layers Thus, a wiring substrate having the substrate body in which separation between the insulating layers is suppressed is obtained.

The wiring board includes both a single wiring board and a multi-wiring board. In other words, it includes a multi-wiring circuit board that includes a product area having a plurality of wiring boards adjacent in vertical and horizontal directions in plan view, and an ear portion having a rectangular frame shape in plan view surrounding the product area. It is.
In addition, ceramic (for example, alumina, aluminum nitride, glass-ceramic), resin (for example, epoxy resin), or the like is employed for the insulating layer forming the substrate body.
Further, the ceramic is obtained by firing the ceramic green sheet, and a resin sheet (including a resin film) is used as the resin, for example.
Further, the concave portion opened on the back surface of the substrate body is provided along the planned cutting surface when the wiring substrate for multi-pieces is separated, for example, with the conductor layer contacting the mounting solder on the side surface. Or a cavity having a side surface and a bottom surface and a recess (groove) that extends across both the back surface and the outer surface of the single substrate body. ) Part (castellation, step part) is also included.

Further, the concave portion may have one or a plurality of step portions along the front surface and the rear surface of the wiring board on the side surface of the concave portion.
The conductor layer is composed of a metallized layer and a metal layer coated on the surface side. The metallized layer is mainly composed of tungsten (hereinafter simply referred to as W and W) when the insulating layer is a high-temperature co-fired ceramic. Abbreviated) or molybdenum (hereinafter abbreviated as Mo). When the insulating layer is a low-temperature co-fired ceramic or resin, it is mainly made of copper (Cu) or silver (Ag).
In addition, the conductor layer is formed, for example, on an electrode pad for mounting an electronic component formed on the bottom surface of the recess (cavity) or on a mounting solder formed on a side surface of the recess (castellation). A mounting conductor to be joined.

Further, in the present invention, the ridge portion protrudes from the bottom surface or the side surface at a corner portion of the bottom surface and the side surface of the concave portion, and is a side view perpendicular to the thickness direction of the substrate body. A wiring board (Claim 2) having an inclined surface inclined with respect to the corner portion side or a curved surface convex toward the corner portion side is also included.
According to this, the fluidity of the metal plating solution at the time of manufacture is promoted by forming the ridges having the inclined surfaces or curved surfaces along the corners in the recesses. The effects (1) to (3) can be obtained more reliably.

Further, in the present invention, the conductor layer is formed on the side surface constituting the recess, and the conductor layer is formed on the metallized layer formed on the side surface side and on the surface side of the metallized layer. A wiring board (Claim 3), wherein the protruding portion is in contact with at least an end portion of the metal layer of the conductor layer formed on the side surface. It is.
According to this, for example, in the conductor layer formed on the side surface of the recess (castellation) that opens on both the back surface and the side surface of the substrate main body, at least at the end of the metal layer, a void is formed on the surface side. Since a metal layer having a nearly uniform thickness is formed, the solder rising part (fillet) used for joining with the motherboard on which the wiring board is mounted is formed with respect to the surface of the metal layer. It can be easily formed in a relatively large area. And since the length which the edge part of the said metal layer and the bottom face of the said concave part contact can be lengthened by the said protruding item | line part, it becomes possible to acquire the said effect (2) still more reliably.

In addition, in the present invention, the conductor layer is formed on the bottom surface constituting the recess, and the conductor layer is formed on the metallized layer formed on the bottom surface side and on the surface side of the metallized layer. A wiring board (Claim 4), wherein the protruding portion is in contact with at least an end portion of the metal layer among the conductor layers formed on the bottom surface. included.
According to this, for example, in the end portion of the metal layer that is a part of the conductor layer formed on the bottom surface of the concave portion (cavity) opened on the surface of the substrate body, there is almost no void and is almost uniform. Since the metal layer having a thickness is formed, stable electrical connection is possible even if an electronic component such as a semiconductor element is mounted on the surface of the metal layer later. Furthermore, since the length of the edge part of the said metal layer and the bottom face of the said recessed part can be lengthened by the said protruding item | line part, the said effect (2) can be acquired more reliably.

  On the other hand, a method of manufacturing a wiring board according to the present invention (Claim 5) is formed by laminating a plurality of insulating layers, and has an opening on at least one of a front surface and a back surface of the substrate body having opposing front and back surfaces. And a method of manufacturing a wiring board having a concave portion having a bottom surface and a side surface, and a conductor layer formed on at least one of the bottom surface and the side surface constituting the concave portion, and having a plurality of opposing front and back surfaces Among the insulating sheets, at least one insulating sheet has a plurality of through holes penetrating between the front surface and the back surface. By laminating the plurality of insulating sheets and pressing them in the thickness direction, The inner surface of the through hole of the insulating sheet having the through hole is a side surface, and the surface or the back surface of another insulating sheet laminated adjacent to the insulating sheet having the through hole is the bottom. And forming a concave portion along the corner of the side surface and the bottom surface, protruding in the thickness direction of the substrate body or in a direction perpendicular to the thickness direction, and one of the adjacent insulating sheets A pressure-bonding step of forming a part of the ridge portion.

According to the manufacturing method of the wiring board, the following effects (4) and (5) can be obtained.
(4) A plurality of insulating sheets including the insulating sheet having the through holes are stacked and bonded in the thickness direction, and a relatively simple crimping process is performed at the corners of the recesses and the bottom and side surfaces of the recesses. It is possible to easily and reliably form the projecting ridge portion along.
(5) Due to the effect (4), it is possible to provide a plurality of the wiring boards efficiently and at low cost by using a multi-cavity form.

The insulating sheet includes a ceramic green sheet (hereinafter simply referred to as a green sheet) and a resin sheet (including a film).
In addition, when a green sheet is used as the insulating sheet between the crimping step and a plating step described later, a step of firing a green sheet laminate in which a plurality of the green sheets are laminated is performed. When using a resin sheet, a curing process is performed in which a laminate of a plurality of the resin sheets is heated and cured.
Furthermore, for example, the solvent content may be different between the adjacent green sheets.
Further, a part of the insulating sheet may be a flat insulating sheet without the through hole.
Further, when all of the plurality of insulating sheets have through holes, the through holes do not overlap with each other and are stacked apart from each other in the vision perpendicular to the planar direction.
In addition, after the metallized layer is fired or cured later, the metal layer is further coated on the surface side exposed to the outside, thereby forming the conductor layer.

Further, in the present invention, in the crimping step, the inner surface of the concave portion is made of an elastic material, and the corner portion between the bottom surface and the side surface constituting the concave portion has a triangular shape or a long portion of the triangular shape. Also included is a method of manufacturing a wiring board (Claim 6) in which the crimping step is performed by inserting a convex portion of a restraining jig so as to form a gap that is a curved side with a slanted side that is loosely recessed.
According to this, the inclined surface or the curved surface is provided along the corner of the concave portion by providing an inclined surface or a convex curved surface on the outer side along the periphery of the flat front end surface of the restraining jig. It is possible to easily and accurately form the ridge portion having the following. Therefore, the effect (4) can be obtained more reliably.
The restraining jig may use an elastic material such as Si rubber for the convex portion.

Furthermore, the present invention includes a step of forming a metallized layer on the inner wall surface of the through hole or on the surface or the back surface of the insulating sheet surrounded by the through hole before the crimping step. A method for manufacturing a wiring board (Claim 7) is also included.
According to this, the following effect (6) can be acquired.
(6) The end portion of the metallized layer is brought into contact with or covered with the convex portion that is formed along the corner of the concave portion on the bottom surface or side surface of the concave portion that is formed in the crimping step. Accordingly, it is possible to reliably form the conductor layer including the metal layer coated on the surface side exposed to the outside of the metallized layer and having excellent conductivity and the like.

In addition, the present invention includes a method for manufacturing a wiring board (Claim 8), which includes a plating step of performing electrolytic metal plating on the surface of the metallized layer exposed to the outside after the crimping step. .
According to this, the conductive layer is formed by coating the metal layer by electrolytic metal plating on the surface side exposed to the outside of the metallized layer formed on the bottom surface or side surface of the concave portion, so that the effect (6) Can be obtained more reliably.
In the plating step, a relatively thick copper layer is formed on the surface of the metallized layer by, for example, electrolytic copper plating, and then electrolytic nickel plating and electrolytic gold plating are sequentially performed on the copper layer. As a result, a relatively thin nickel layer and an extremely thin gold layer are coated.

(A) is a vertical sectional view showing a wiring board of one form according to the present invention, (a) is a partial perspective view visually shown by an arrow a in (A), and (B) is a vertical showing a wiring board of the same kind as the above. Sectional drawing, (b) is the partial perspective view by the vision of the arrow b in (B). (A) is a partially enlarged vertical sectional view near the concave portion shown in FIG. 1 (a), and (B) is a partial enlarged vertical sectional view near the concave portion shown in FIG. 1 (b). (A)-(D) is a partial vertical sectional view which shows the wiring board of a different form, (a) is the partial expanded sectional view in (A), (b) is the partial expanded sectional view in (B). (A), (B) is a partial vertical sectional view which shows the wiring board of a different form. (A)-(C) are the schematic which shows the manufacturing process of the wiring board of FIG. 1 (A), (B), (D1)-(D3) is the schematic which shows the effect | action of one form in the crimping | compression-bonding process. (A1) to (A3) are schematic diagrams showing the operation of different forms of the crimping step, (B1) to (B3) are schematic diagrams showing the operation of the crimping step using a restraining jig, (C), (D ) Is a partial vertical cross-sectional view showing a green sheet laminate obtained by a crimping process. (A), (B) is a partial vertical sectional view showing a wiring board for multi-cavity after the firing process, and (C), (D) are schematic views showing a plating process on the wiring board.

Hereinafter, modes for carrying out the present invention will be described.
1A and 1B are vertical sectional views showing wiring boards 1a and 1b of the same type, FIG. 1A is a partial perspective view visually shown by an arrow a in FIG. ) Is a partial perspective view of the arrow b in FIG.
As shown in FIGS. 1A and 1B, the wiring boards 1a and 1b are formed by laminating a plurality of ceramic layers (insulating layers) c1 to c4, and have a front surface 3 and a back surface 4 facing each other. 2 and a pair of left and right recesses in the figure that open across the back surface 4 and the outer surface 2 s of the substrate body 2, and a cavity (recess) 5 having an opening on the surface 3 and having a bottom surface 6 and a side surface 7. (Casters) 8, a plurality of electrode pads (conductor layers) 15 formed on the bottom surface 6 of the cavity 5, and a conductor layer 19 formed on the side surface 9 for each recess 8.

The ceramic layers c1 to c4 are mainly composed of alumina, for example.
Further, the front surface 3 and the back surface 4 of the substrate body 2 and the bottom surface 6 of the cavity 5 have a rectangular shape (square or rectangular) in plan view.
Further, as will be described later, the electrode pad 15 has a metallized layer 15a on the bottom surface 6 side of the cavity 5 and a metal layer 15b coated on the surface side, and above the electrode pad 15, Subsequently, an electronic component 20 such as a semiconductor element is mounted.
In addition, the conductor layer 19 has a metallized layer 19a formed on the side surface 9 side of the recess 8 and a metal layer 19b coated on the surface side, as will be described later.

As shown in FIGS. 1A and 1B, a plurality of external connection terminals 18 whose one ends are individually connected to the conductor layer 19 are formed on the back surface 4 of the substrate body 2. As will be described later, the external connection terminal 18 also includes a metallized layer 18a formed on the back surface 4 side and a metal layer 18b coated on the front surface side.
A plurality of inner layer wirings 16 are formed between the ceramic layers c2 to c4 constituting the substrate body 2, that is, between the electrode pads 15, the inner layer wirings 16 and the external connection terminals 18. In addition, they can be electrically connected to each other through via conductors 17 that individually penetrate the ceramic layers c2 to c4.
Further, as shown in FIGS. 1 (a) and 1 (b), the recess 8 as a whole has a rectangular parallelepiped shape or an elongated semi-long cylindrical shape along the major axis direction, and is horizontally aligned with a plurality of side surfaces 9 along the vertical direction. It consists of a single bottom surface (ceiling surface) 10 along the direction.
The inner layer wiring 16 and the via conductor 17 are made of W or Mo.
The metallized layer 15a of the electrode pad 15, the metallized layer 18a of the external connection terminal 18, and the metallized layer 19a of the conductor layer 19 are also made of W or Mo.
Further, the metal layer 15b of the electrode pad 15, the metal layer 18b of the external connection terminal 18, and the metal layer 19b of the conductor layer 19 are, for example, a copper layer thicker than the metallized layer 15a, a nickel layer thinner than the copper layer, And three layers of gold layers.

As shown in FIGS. 1A and 1B, the inclined surface is inclined with respect to the corner portion along the corner portion between the bottom surface 6 and the side surface 7 of the cavity 5 that opens to the surface 3 of the substrate body 2. A ridge portion 11 having a triangular cross section or a ridge portion 13 having a curved surface that protrudes toward the corner portion is formed. The ridges 11 and 13 are formed by projecting a part of the ceramic layer c4 along the plane direction in the crimping process during manufacturing. In addition, the said protruding item | line parts 11 and 13 can also be formed by protruding a part of ceramic layer c3 along the thickness direction.
In addition, as shown in FIGS. 1A, 1A, and 2A, the concave portion 8 is inclined with respect to the corner portion along the corner portion of the side surface 9 and the bottom surface (ceiling surface) 10. A convex strip 12 having a triangular cross section having an inclined surface 12t is formed. A metallized layer 19a is formed on the entire side surface 9, and a conductor layer 19 is formed by the metallized layer 19a and a metal layer 19b coated on the surface side. The end (upper end) of the metal layer 19b is in contact with the ridge 12 as shown in FIG.
The metallized layer 19a is continuous with the metallized layer 18a of the external connection terminal 18 formed on the back surface 4 of the substrate body 2, and the metal layer 19b is continuous with the metal layer 18b of the external connection terminal 18. ing.

Further, as shown in FIGS. 1B, 1B, and 2B, a curved surface 14r that protrudes toward the corner along the corner between the side surface 9 and the bottom surface 10 of the recess 8 is provided. A ridge 14 having a triangular cross section is formed. A metallized layer 19a similar to that described above is formed on the entire side surface 9, and a conductor layer 19 is formed by the metallized layer 19a and the metal layer 19b coated on the surface side. The end (upper end) of the metal layer 19b is adjacent to the ridge 14 as shown in FIG. The metallized layer 19a is also continuous with the metallized layer 18a of the external connection terminal 18, and the metal layer 19b is also continuous with the metal layer 18b of the external connection terminal 18.
The ridges 12 and 14 are formed by protruding a part of the ceramic layer c2 along the thickness direction in the crimping process during manufacturing.

3 (A) and 3 (B) are partial vertical sectional views showing wiring boards 1c and 1d having different forms, and FIGS. 3 (a) and 3 (b) are partially enlarged views in the above (A) and (B). It is.
As shown in the figure, the wiring boards 1c, 1d have a substrate body 2a having three surface ceramic layers c2 to c4 that are the same as those described above, and have a front surface 3 and a back surface 4 facing each other. The above-mentioned protruding ridges 11 or protruding ridges 13 are formed along the corners of the bottom surface 6 and the side surface 7 of the cavity (concave portion) 5.
As shown in FIGS. 3 (a) and 3 (b), the ridges 11 and 13 are formed by projecting part of the ceramic layer c3 along the thickness direction at the time of manufacture, and the same inclined surface 11t or curved surface as described above. It has a surface 13r. An electrode pad (conductor layer) 15 is disposed adjacent to the ridges 11 and 13. The electrode pad 15 is formed of a metallized layer 15a formed on the bottom surface 6 side of the cavity 5 and a metal layer 15b coated on the surface side. Furthermore, the end portions of the metal layer 15b which is a part of the electrode pad 15 are in contact with the ridges 11 and 13 individually.
The back surface 4 of the substrate body 2a is a flat surface, and a plurality of external connection terminals 18 that can be electrically connected to the electrode pad 15 via the same inner layer wiring 16 and via conductor 17 are provided on the back surface 4. It is formed on the peripheral side.

3 (C) and 3 (D) are partial vertical cross-sectional views showing wiring boards 1e and 1f of further different forms. As shown in the figure, the wiring boards 1e and 1f are composed of a substrate body 2b having three surface ceramic layers c1 to c3 which are the same as those described above and having a front surface 3 and a back surface 4 facing each other, and the back surface 4 and the outer surface 2s. And a recess 8 that opens over the two. Along the corners of the side surface 9 and the bottom surface 10 of the concave portion 8, the same ridge portion 12 or the ridge portion 14 is formed, and the conductor layer is in contact with the ridge portions 12, 14. An end portion (upper end portion) of the metal layer 19b which is a part of the contact portion 19 is in contact with the protruding strip portions 12 and 14.
The surface 3 of the substrate body 2b is a flat surface, and a plurality of electrode pads 15 similar to the above are formed on the center side. The electrode pad 15 can be electrically connected to the external connection terminal 18 and the conductor layer 19 on the back surface 4 side through the same inner layer wiring 16 and via conductor 17 as described above.
Further, the wiring boards 1e and 1f of the present embodiment do not have the cavity (concave part) 5 opened on the surface 3 of the substrate body 2b, and the end part of the metal layer 15b in the electrode pad 15 is formed with the ridge parts 11 and 13. It is different from the above-mentioned form in that it is not in contact.

FIGS. 4A and 4B are partial vertical cross-sectional views showing wiring boards 1g and 1h having different forms. As shown in the figure, the wiring boards 1g and 1h are formed by laminating two ceramic layers c1 and c4 which are the same as described above, and have a substrate body 2c having a front surface 3 and a back surface 4 facing each other, and an opening in the front surface 3. A cavity (concave portion) 5 and a concave portion 8 that opens across the back surface 4 and the outer surface 2s. Along the corner portion between the bottom surface 6 and the side surface 7 of the cavity 5, the same protruding strip portion 11 or protruding strip portion 13 is formed. Further, along the corner portions of the side surface 9 and the bottom surface 10 of the concave portion 8, the same convex strip portion 12 or convex strip portion 14 is formed. The electrode pad 15 formed on the bottom surface 6 of the cavity 5, the external connection terminal 18 formed on the back surface 4 of the substrate body 2c, and the conductor layer 19 formed on the side surface 9 of the recess 8 are ceramic layers. Conduction is possible through a via conductor 17 penetrating c1.
In the wiring board 1g, the protrusions 13 are provided along the corners in the cavity 5, or in the wiring board 1h, the protrusions are provided along the corners in the cavity 5. It is good also as a form which provided the part 11. FIG.

In the wiring substrates 1a to 1h described above, the thickness direction of the substrate bodies 2, 2a to 2c, or along the corners of the bottom surfaces 6 and 10 and the side surfaces 7 and 9 constituting the cavity 5 and the recess 8 or , And projecting along a direction orthogonal to the thickness direction, and at least one of the ridges 11 to 14 made of a part of any one of the ceramic layers c2 to c4 is located, so that the electrode pad 15 and the When the metal layer 19b, which is a part of the conductor layer 19, is formed by metal plating, the periphery of the plating solution is promoted by the ridges 11 to 14 near the corners of the cavity 5 and the recess 8. Therefore, the metal layers 15b and 19b formed by metal plating in the plating process at the time of manufacture do not contain voids and are firmly and accurately coated with a desired thickness.
Further, since any one of the ridges 11 to 14 is formed along the corners in the cavity 5 and the recess 8, the metallization that is a part of the conductor layers 15 and 19 in the vicinity of the corners. Since moisture or outside air from the outside enters the layers 15a and 19a and is difficult to come into contact with the layers 15a and 19a, the reliability regarding the electrical characteristics of the conductor layers 15 and 19 is improved.

Furthermore, since the area for lamination | stacking with the ceramic layers c2-c4 which protruded the said protruding item | line parts 11-14 and the other ceramic layers c1-c4 laminated | stacked adjacent to this increases, these adjacent ceramic layers It is assumed that the substrate main bodies 2 and 2a to 2c are suppressed in which the displacement between the layers and the separation between the ceramic layers are suppressed.
Therefore, according to the wiring boards 1a to 1h, the effects (1) to (3) can be obtained.

In the following, a method for manufacturing the wiring boards 1a and 1b will be described in the form of multiple pieces.
As shown in FIG. 5 (A), four green sheets g1 to g4 that contain alumina powder and the like and are used for many pieces were prepared in advance by a known method. In the figure, the broken lines in the green sheets g1 to g4 are virtual cutting planes used when the sheets are separated into pieces. Further, the substrate region 23 sandwiched between the pair of left and right broken lines becomes one of the wiring boards 1a and 1b later.
First, as shown in FIG. 5A, the green sheets g1 to g4 are individually subjected to known punching to penetrate between the front surface 21 and the back surface 22 of the green sheets g1 to g4. At least one of the holes 24 and 25 or the via hole 26 having a circular cross section was formed. The through hole 24 has a rectangular shape in plan view, and the through hole 25 has an elongated rectangular shape or oval shape in plan view.

Next, as shown in FIG. 5B, the via holes 26 of the green sheets g1 to g3 are filled with a conductive paste containing W powder or Mo powder to form an unfired via conductor 17, Along the inner wall surface of the through-hole 25 of the green sheet g1, a metal paste layer 19a having a long and narrow cylindrical shape was applied in the illustrated front-rear direction by using a negative pressure with the same conductive paste as described above.
Next, the same conductive paste as described above is screen-printed on the surface 21 of the green sheets g1 to g4 to form an unfired inner layer wiring 16 and a metallized layer 15a as shown in FIG. 5B. did. The inner layer wiring 16 and the metallized layer 15a were connected to one of the via conductors 17.
At the same time, the same conductive paste as described above was screen-printed on the back surface 22 of the green sheet g1 to form a plurality of unfired metallized layers 18a as shown. One end of the metallized layer 18a was connected to the lower end of the metallized layer 19a.

Further, the green sheet g4, the green sheets g2 and g3 on which the inner layer wiring 16 and the via conductor 17 are formed, and the green sheet on which the inner layer wiring 16, the via conductor 17 and the metallized layers 18a and 19a are formed. g1 were laminated according to the required order.
As a result, as shown in FIG. 5 (C), an opening is formed along the cavity 5 which is open on the front surface 3 and which is composed of the bottom surface 6 and the four side surfaces 7 and the planned cutting surface (broken line in the figure) on the back surface 4. And the green sheet laminated body 30 which has the some recessed part 28 which makes the inner wall surface of the said through-hole 25 a side surface was obtained.
Subsequently, a crimping process for crimping the green sheet laminate 30 along its thickness direction was performed.

At this time, as shown in FIG. 5 (D1), in the vicinity of the corner between the bottom surface 6 and the side surface 7 of the cavity 5 between the green sheets g3 and g4, for example, in FIG. 3 (D2) and (D3) As indicated by the solid line arrow, a part of the green sheet g4 protrudes along the bottom surface 6 so that the cross-section has a triangular shape and has an inclined surface 11t or a curved line portion 11t. A ridge 13 having a surface 13r was formed.
5 (D2) and (D3), the ridges 11 and 13 are formed by projecting part of the green sheet g3 along the thickness direction. In some cases.
Moreover, in order to form the said protruding item | line parts 11 and 13, it becomes still more reliable by making different content of the solvent between the said green sheets g3 and g4, for example.

Moreover, in the said crimping | compression-bonding process, as shown to FIG. 6 (A1), the corner | angular part of the side surface 25 and the bottom face (the said back surface) 22 of the recessed part 28 formed between the green sheets g1 and g2 of the said green sheet laminated body 30. For each neighborhood, for example, as shown in FIGS. 6A2 and 6A3, a part of the green sheet g2 protrudes in the plane direction of the side surface 25 and along the thickness direction of the laminate 30. Thus, the ridge portion 12 having a triangular cross section and the inclined surface 12t or the ridge portion 14 having the curved surface 14r was formed.
In addition, when forming the said protruding item | line parts 12 and 14, it becomes still more reliable by making the content of the solvent between the said green sheets g1 and g2 differ.

Further, in the crimping step, as shown in FIG. 6B1, a restraining jig having a convex portion 32 made of an elastic material such as synthetic rubber or synthetic resin may be used inside the concave portion 28, for example. . In the vicinity of the flat front end surface 33 of the convex portion 32 of the restraining jig, for example, a curve that protrudes outward, corresponding to each corner near the side surface 25 and the bottom surface 22 constituting the concave portion 28. Surface 34 is pre-arranged.
Therefore, as shown in FIG. 6 (B2), when the convex portion 32 of the restraining jig is inserted inside the concave portion 28, the curved surface 34, the side surface 25 and the bottom surface 22 of the concave portion 28 Between each corner, a gap is formed that has a triangular cross section and a curved side with a long side and a slanted side that is loosely recessed. In this state, as indicated by the arrows in the figure, the green sheets g1 and g2 are pressure-bonded along the thickness direction.

As a result, as shown in FIG. 6 (B3), when a part of the green sheet g2 protrudes in the plane direction of the side surface 25 and along the thickness direction of the laminate 30, the protruding portion is By being limited to the gap, it is possible to reliably form the ridge 14 having a triangular cross section and a curved surface 14r in the vicinity of the corner between the side surface 25 and the bottom surface 22 of the recess 28. it can.
In addition, by providing a chamfered inclined surface along the periphery of the flat distal end surface 33 of the convex portion 32 of the restraining jig, the cross section has a triangular shape near each corner portion, and The ridge portion 12 having the inclined surface 12t can be reliably formed.
Further, in the restraining jig, a flat base portion (not shown) for erecting the plurality of convex portions 32 is a hard plate material in surface contact with the back surface 4 of the green sheet laminate 30, or the rubber. Any of a slightly soft plate material having elasticity such as may be used.

By passing through the above-mentioned crimping step, as shown in FIG. 6C, the convex strips 11 are provided along the corners of the bottom surface 6 and the side surface 7 of the cavity 5 that opens to the surface 3. And the green sheet laminated body 30 which has the said protruding item | line part 12 along every corner | angular part of the side surface 25 and the bottom face 22 of the said some recessed part 28 opened to the back surface 4 was obtained.
Alternatively, as shown in FIG. 6 (D), the protrusions 13 are provided along the corners of the bottom surface 6 and the side surface 7 of the cavity 5, and the side surface 25 and the bottom surface 22 for each recess 28 are formed. The green sheet laminated body 30 which has the said protruding item | line part 14 along every corner | angular part was able to be obtained.
Next, the green sheet laminate 30 was fired, and the metallized layers 15a, 18a, 19a, the inner layer wiring 16 and the via conductors 17 were fired simultaneously with the green sheets g1 to g4.

As a result, as shown in FIGS. 7A and 7B, the green sheets g1 to g4 become ceramic layers c1 to c4, and the metallized layers 15a, 18a, and 19a that have not been fired and the inner layer wiring 16 are formed. And the wiring board 36 for multi-pieces which has the said board | substrate area | region 23 by which the via conductor 17 was baked side by side adjoining vertically and horizontally in planar view was obtained. In the wiring board 36, an electrode for electrolytic plating (not shown) is provided on the outer surface of the ear portion having a rectangular frame shape in plan view surrounding the outside of the product region including the plurality of substrate regions 23. A plurality of was formed.
Then, the wiring board 36 was sequentially immersed in an electrolytic copper plating bath, an electrolytic nickel plating bath, and an electrolytic gold plating bath (not shown) to perform a plating process for applying three types of electrolytic metal plating.

For example, as illustrated on the left side of FIGS. 7C and 7D, in the recess 28 of the wiring board 36, when each of the plating solutions is sequentially immersed in the three electrolytic metal plating baths, The convex strip 12 formed along each corner of the side surface 25 and the bottom surface 22 of the concave portion 28 or the convex strip 14 gave high fluidity to flow in and out relatively smoothly. .
As a result, as shown on the right side of FIGS. 7C and 7D, on the surface side exposed to the outside of the metallized layers 18a and 19a, a metal layer composed of three layers of a copper layer, a nickel layer, and a gold layer. 18b and 19b were tightly coated with high accuracy and almost uniform thickness. Thus, the conductor layer 19 composed of the metallized layer 19a and the metal layer 19b is formed on the side surface 25 of the recess 28, and the external connection terminal 18 composed of the metallized layer 18a and the metal layer 18b is formed. .

At the same time, the surface exposed to the outside of the metallized layer 15a formed on the bottom surface 6 of the cavity 5 is coated with the metal layer 15b having the same structure as that described above in the plating step. (Conductor layer) 15 was formed.
After the above plating process, by performing the singulation process of dividing the multi-piece wiring board 36 into a plurality of pieces along the planned cutting surface indicated by the broken line, the above-described FIG. , (B), a plurality of wiring boards 1a and 1b can be obtained. At this time, the concave portion 28 is divided into a pair of the concave portions 8, and the conductor layer 19 is formed on the side surface 9 of each concave portion 8. It became the outer surface 2s.
In addition, the said wiring board 1c, 1d is obtained by performing each said process with respect to the said green sheets g2-g4 shown in the said FIG. 5, and each said process is performed with respect to the said green sheets g1-g3. Thus, the wiring boards 1e and 1f are obtained. Furthermore, it is possible to obtain the wiring boards 1g and 1h by performing the respective steps on the green sheets g1 and g4 shown in FIG.

In the method of manufacturing the wiring boards 1a and 1b as described above, a relatively simple crimping process in which a plurality of green sheets g1 to g4 including those having the through holes 24 and 25 are stacked and crimped in the thickness direction. Thus, the ridges 11 to 14 could be easily and reliably formed along the concave portions 5 and 28 and the bottom surfaces 6 and 22 and the side surfaces 7 and 25 of the concave portions 5 and 28. Due to this, the wiring board 36 for multi-piece production is obtained by passing through the manufacturing steps in the form of multi-piece production, and further, the plurality of wiring boards 1a and 1b can be efficiently and cost-effectively obtained. Could be provided.
Further, on any one of the ridges 11 to 14 formed along the corners of the recesses 5 and 28 on the bottom surfaces 6 and 22 or the side surfaces 7 and 25 of the recesses 5 and 28 formed in the crimping step. Since the end portions of the metallized layers 15a and 19a are in contact with or covered with the metallized layers 15a and 19a, the metallized layers 15a and 19a are covered with the metal layers 15b and 19b which are exposed to the outside. In addition, the conductor layers 15 and 19 could be reliably formed.
Therefore, it has been found that the effects (4) to (6) can be obtained by the method of manufacturing the wiring boards 1a and 1b.

The present invention is not limited to the embodiments described above.
For example, the insulating layer constituting the substrate body may be a high-temperature co-fired ceramic other than the alumina (for example, mullite or aluminum nitride), a low-temperature co-fired ceramic such as glass-ceramic, or an epoxy-based material, for example. It is good also as what consists of these resin. In the case of the latter insulating layer, copper or silver is applied to the conductors such as the metallized layers 15a and 19a.
Further, in the single wiring substrate 1a to 1h, the protruding strips 11 and 12 having the inclined surfaces 11t and 12t and the protruding strips 13 and 14 are mixed with the curved surfaces 13r and 14r. It may be as well.

Further, the concave portion 8 may have a semicircular shape in plan view, and may have a semicircular bottom surface 10 and a semicylindrical side surface 9. In the case of this form, the said recessed part 28 is made into the form which consists of the bottom plate 22 and the column-shaped side surface 25 which are circular in planar view.
In the wiring board 1x, the cavity (concave part) 5 and the concave part 8 may be formed on the same front surface 3 or back surface 4 of the substrate body 2x.
Further, the cavity (recess) 5 and the recess 28 may be formed on the same front surface 3 or rear surface 4 of the multi-wiring wiring board 36.
In addition to the green sheet gx, an epoxy-based or polyimide (PI) -based resin film may be used as the insulating sheet. In the case of such a form, a curing process is performed after the crimping process.
In addition, the plating step may include a form in which a copper layer and a gold layer are coated on a surface of the metallized layer, a form in which a nickel layer and a gold layer are coated, or a copper layer, a nickel layer, a palladium layer, and a gold layer. It is good also as a form etc. which coat | cover 4 layers with a layer.

  According to the present invention, a substrate body having a plurality of insulating layers stacked and having a front surface and a back surface facing each other, and a void is formed on the surface of the conductor layer formed on the bottom surface or side surface of the recess opening in at least one of the front surface and the back surface. It is possible to provide a wiring board coated with a metal layer without any metal and a manufacturing method capable of easily manufacturing the wiring board.

1a to 1h, 36 ... wiring board 2, 2a to 2c ... board body 3 ........... front side of board body 4 ................ back side of board body 5 .......... ...... Cavity (concave)
6,10 ......... bottom surface 7,9 ............ side surface 8,28 ............... concave
11-14 ............ Projection 11t, 12t ...... Inclined surface 13r, 14r …… Curved surface 15 …………………… Electrode pad (conductor layer)
15a, 19a ...... Metalized layer 15b, 19b ... Hand metal layer 19 ............... Conductor layer 21 ............... Green sheet surface 22 ............... Green sheet back surface 24, 25 ………… Through hole 32 ……………… Convex part of restraining jig c1 to c4 ………… Ceramic layer (insulating layer)
g1 to g4 …… Green sheet (insulating sheet)

Claims (8)

A plurality of insulating layers, and a substrate body having opposite front and back surfaces;
A recess having an opening on at least one of the front surface and the back surface of the substrate body and having a bottom surface and a side surface;
A wiring board having a conductor layer formed on at least one of the bottom surface and the side surface constituting the recess,
Along the corners of the bottom surface and the side surface constituting the concave portion, and having a ridge portion projecting in the thickness direction of the substrate body or in a direction perpendicular to the thickness direction and comprising a part of the insulating layer ing,
A wiring board characterized by that. The ridge portion protrudes from the bottom surface or the side surface at a corner portion between the bottom surface and the side surface of the concave portion, and is inclined with respect to the corner portion in a side view perpendicular to the thickness direction of the substrate body. It has an inclined surface or a curved surface that is convex on the corner side,
The wiring board according to claim 1. The conductor layer is formed on the side surface constituting the recess, and the conductor layer has a metallized layer formed on the side surface side and a metal layer formed on the surface side of the metallized layer. The protruding portion is in contact with at least an end portion of the metal layer of the conductor layer formed on the side surface;
The wiring board according to claim 1 or 2, wherein The conductor layer is formed on the bottom surface constituting the recess, and the conductor layer has a metallized layer formed on the bottom surface side and a metal layer formed on the surface side of the metallized layer. The protruding portion is in contact with at least an end portion of the metal layer of the conductor layer formed on the bottom surface,
The wiring board according to claim 1 or 2, wherein A substrate body having a plurality of insulating layers stacked and having opposing front and back surfaces, a recess opening at least one of the front and back surfaces of the substrate body and having a bottom surface and side surfaces, and a bottom surface forming the recess And a conductor layer formed on at least one of the side surfaces, and a method of manufacturing a wiring board,
Among the plurality of insulating sheets having front and back surfaces facing each other, at least one insulating sheet has a plurality of through holes penetrating between the front and back surfaces, and the plurality of insulating sheets are laminated and By crimping along the thickness direction,
And forming a recess having the inner wall surface of the through hole of the insulating sheet having the through hole as a side surface and the bottom surface of the surface or the back surface of another insulating sheet laminated adjacent to the insulating sheet having the through hole. ,
A ridge portion that is along a corner portion of the side surface and the bottom surface, protrudes in the thickness direction of the substrate body or in a direction orthogonal to the thickness direction, and is formed of a part of any one of the adjacent insulating sheets. Including a crimping step to form,
A method of manufacturing a wiring board. In the crimping step, the inside of the concave portion is made of an elastic material, and the corner of the bottom surface and the side surface constituting the concave portion has a triangular cross section or a curved surface in which the long side of the triangular side is gently concave. Insert the convex part of the restraining jig so as to form a gap that is a side and perform the above crimping step.
The method for manufacturing a wiring board according to claim 5. Before the press-bonding step, a step of forming a metallized layer on the inner wall surface of the through hole or on the front surface or the back surface of the insulating sheet surrounded by the through hole,
The method for manufacturing a wiring board according to claim 5 or 6. After the pressure bonding step, a plating step of performing electrolytic metal plating on the surface exposed to the outside of the metallized layer,
The method for manufacturing a wiring board according to any one of claims 5 to 7, wherein:

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