JP2006332605A - Wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring board in which a light emitting element is mounted on the bottom face of a cavity, sealing resin filling that cavity is held not to be exfoliated easily, and light from the light emitting element can be reflected efficiently. <P>SOLUTION: The wiring board comprises a substrate body 2 composed of ceramic (insulating material) and having a surface 3 and a rear surface 4, a cavity 5 having an opening in the surface 3 of the substrate body 2 and having a protrusion 8 protruding toward the central side of the opening on the side of the circular bottom face 6, the substantially conical side face 7 and the surface 3 of the side face 7, a metal layer 11 formed on the side face 7 of the cavity 5, and an insulating portion 10 formed on the rear surface 4 side of the protrusion 8 while having a curved surface 10a recessed to make an obtuse angle θ against the metal layer 11. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wiring board on which a light emitting element is mounted on a bottom surface of a cavity.

In a wiring board on which a light emitting element is mounted, a light reflecting layer made of metal is formed on a side surface of a cavity in which the light emitting element is mounted, and a sealing resin is filled in the cavity so that the surface is flat. Thus, the light emitted from the light emitting element can be made clear.
For example, a ceramic frame body having a through hole is joined on a flat ceramic base, and a metal layer containing a refractory metal such as W or Mo and a metal plating layer containing Co are sequentially formed on the inner surface of the through hole. An attached light emitting element storage package has been proposed (see, for example, Patent Document 1).
On the other hand, there has also been proposed a photoelectric device in which a photoelectric element is arranged in an opening (cavity) of a package and a holding means for holding the mold resin filled in the opening so as not to peel off is provided on a side surface of the opening ( For example, see Patent Document 2).

JP 2004-228549 A (pages 1 to 9, FIGS. 1 and 4) Japanese Patent Laid-Open No. 11-74561 (Pages 1-8, FIGS. 1-5)

By the way, among the light reflection layers covering the metal layer provided on the side surface of the cavity where the light emitting element is mounted, the metal plating layer such as Ag positioned on the outermost layer is, for example, the side surface at the upper end portion on the side surface of the cavity. The thickness of the Ag plating layer is thinner than the intermediate position.
In addition, as in the photoelectric device of Patent Document 2, when a holding means having a protruding cross-sectional shape for holding the mold resin is provided on the side surface of the cavity in which the light emitting element is disposed, the metal provided on the side surface of the cavity is provided. When electrolytically plating a Ni, Au, Ag plating layer or the like on the layer, the plating solution is less likely to circulate immediately below the holding means. As a result, the thickness of the metal plating layer coated on the upper end portion of the metal layer located immediately below the holding means, particularly the uppermost Ag plating layer, is reduced, and the underlying metal layer and the components of the metal plating layer are Ag plated. Precipitation occurs on the surface of the layer, and discoloration is likely to spread beyond the upper end. For this reason, there is a problem that it becomes more difficult to efficiently reflect light from the light emitting element.

  The present invention solves the problems described in the background art, the light emitting element is mounted on the bottom surface of the cavity, and the sealing resin filled in the cavity is held difficult to peel off. It is an object to provide a wiring board capable of efficiently reflecting light.

Means for Solving the Problems and Effects of the Invention

In order to solve the above-mentioned problems, the present invention is provided with a convex portion for holding a sealing resin in the opening of the cavity and reliably prevents discoloration of the metal plating layer due to insufficient circulation of the plating solution. , It was conceived.
That is, the first wiring board according to the present invention (Claim 1) is made of an insulating material and has a substrate body having a front surface and a back surface, an opening on the surface of the substrate body, a bottom surface, a side surface, and the like. A cavity having a convex portion protruding toward the opening on the front surface side of the side surface, a metal layer formed on the side surface, and an insulating portion forming an obtuse angle with the metal layer on the back surface side of the convex portion And comprising.

  According to this, since the insulating portion is formed on the back surface side of the convex portion so as to form an obtuse angle with the metal layer formed on the side surface of the cavity, the metal is formed on the side surface of the cavity by electrolytic plating. When forming the plating layer, a sufficient circulation of the plating solution can be secured. As a result, the thickness of the metal plating layer formed on the upper end side of the metal layer is substantially the same as the thickness of the metal plating layer formed at the center of the metal layer. As a result, even on the upper end side of the metal layer, the metal such as Ni that forms the underlying metal plating layer is less likely to be deposited on the surface of the uppermost metal plating layer such as an Ag plating layer. Can prevent the discoloration of the uppermost Ag plating layer from spreading. In addition, since the convex portion protrudes toward the center of the opening at the opening of the cavity, the sealing resin filled in the cavity can be held without being peeled from the cavity. It becomes possible. Therefore, it is possible to efficiently radiate light from the light emitting element mounted on the bottom surface of the cavity to the outside over a long period of time.

The insulating material forming the substrate body includes, for example, a ceramic mainly composed of alumina, glass-ceramic, which is a kind of low-temperature firing, or epoxy resin, for example.
In addition, the cavity has a substantially conical shape whose diameter is reduced on the bottom side with respect to the opening side, a substantially elliptical cone shape, a substantially long cone shape, a polygonal pyramid shape of a quadrangular pyramid or more, and an overall cylindrical shape, elliptical prism shape, A long cylindrical shape or a polygonal column shape including a square column is also included.
Furthermore, the said convex part includes the form located apart from each other in a plurality of locations in the opening part of the cavity, in addition to the form located on the entire circumference along the opening part of the cavity.
The metal layer is made of W, Mo, Cu, Ag or the like when the insulating material is ceramic or glass-ceramic, and Cu or the like when the insulating material is resin. The metal plating layer formed on such a metal layer is composed of an underlying Ni plating layer or the like, an intermediate Au plating layer, and an Ag, Pt, Rh, or Pd reflection plating layer formed thereon. Is done.
Furthermore, the obtuse angle is desirably greater than 90 degrees and 140 degrees or less.
In addition, the light emitting element includes a light emitting diode (LED), a semiconductor laser (LD), and the like.

  On the other hand, the second wiring board according to the present invention (Claim 2) is made of an insulating material and has a substrate body having a front surface and a back surface, an opening on the surface of the substrate body, a bottom surface, a side surface, and A cavity having a convex portion projecting toward the center of the opening on the side surface, a metal layer formed on the side surface, and an insulating portion covering at least the upper end of the metal layer are provided. .

  According to this, since the insulating portion covers at least the upper end portion of the metal layer formed on the side surface of the cavity, the metal plating is not formed in the portion where the plating solution just under the convex portion is difficult to circulate. In other words, since only the portion of the metal layer where the circulation of the plating solution is sufficiently secured is exposed from the insulating portion, the metal plating layer can be formed on the metal layer with a substantially uniform thickness. it can. For this reason, by removing the portion where the metal such as Ni that forms the underlying metal plating layer is likely to precipitate on the surface of the uppermost metal plating layer such as the Ag plating layer, the uppermost Ag plating layer or the like can be obtained. Prevents discoloration from spreading. In addition, since the convex portion protrudes toward the center of the opening at the opening of the cavity, the sealing resin filled in the cavity can be held without being peeled from the cavity. It becomes possible. Therefore, it is possible to efficiently radiate light from the light emitting element mounted on the bottom surface of the cavity to the outside over a long period of time.

The wiring board of the present invention also includes a wiring board (Claim 3) in which the insulating portion has a concave curved surface in a cross section perpendicular to the surface of the substrate body.
The above “curved surface” includes, for example, one having an overall shape such as an arc shape, a round shape, a spherical shape, a parabola shape, a hyperboloid shape, and the like, and includes locally fine unevenness. Also good. The obtuse angle is formed between the tangent line near the center of the curved surface and the metal layer formed on the side surface of the cavity.
According to this, because at least one of the insulating part having a curved surface with a recessed cross-sectional shape made of the same material as the insulating material of the convex part and the insulating part having the obtuse angle is located on the back side of the convex part, When the metal plating layer is formed by electrolytic plating on the metal layer formed on the side surface of the cavity, the plating solution can be easily circulated. As a result, the thickness of the end portion of the formed metal plating layer is substantially the same as the central portion thereof, so that a metal such as Ni that forms the underlying metal plating layer is deposited at the end portion, and the uppermost metal plating is formed. Discoloration is less likely to spread on a layer such as a g plating layer. Therefore, it is possible to efficiently radiate light from the light emitting element mounted on the bottom surface of the cavity to the outside over a long period of time.

Furthermore, in the wiring board of the present invention, the insulating portion has a tapered surface inclined so that the cavity spreads from the front surface side to the back surface side of the substrate body in a cross section perpendicular to the surface of the substrate body. A wiring board (claim 4) is also included.
The “tapered surface” is not limited to a single inclined surface as a whole, but also includes a plurality of inclined surfaces having different inclination angles.
According to this, the insulating part which has the taper surface which inclines so that a cavity may spread from the surface side of the substrate body toward the back side, which consists of the same material as the insulating material of the convex part on the back side of the convex part, Since at least one of the insulating portions is positioned so as to form the obtuse angle, the plating solution can be easily circulated. As a result, the end portion of the metal plating layer and the central portion thereof have a substantially uniform thickness, so that the metal of the underlying metal plating layer is unlikely to deposit on the surface of the uppermost metal plating layer at the end portion. Discoloration hardly spreads over the upper metal plating layer. Therefore, light from the light emitting element mounted on the bottom surface of the cavity can be efficiently emitted to the outside over a long period of time.

In other words, in the present invention, the side surface of the cavity is an inclined surface that is inclined so as to spread from the back surface (bottom surface of the cavity) side of the substrate body toward the surface side of the substrate body, May also be included. In this case, the light from the light emitting element mounted on the bottom surface of the cavity can be reflected at a relatively wide angle.
In addition, the present invention may include a wiring board in which the insulating layer that forms the convex portion and the side surface of the cavity is formed by another insulating layer that is stacked on each other.
In this case, a solvent is applied to the back side of the insulating layer forming the convex portion to soften it, or one insulating layer having an insulating paste formed on the back side, and the other having a through-hole serving as a side surface of the cavity. By laminating and press-bonding an insulating layer, the cavity excluding the bottom surface is formed, and the insulating portion having the curved surface or the tapered surface can be easily formed at the position on the back surface side of the convex portion. Become.
In addition, when the insulating layer is made of ceramic, the insulating portion having a curved surface or a tapered surface can be formed by the above method even when the insulating layer is made of various resins.

  Furthermore, the present invention may include a wiring board in which a continuous metal layer is formed on the side surface of the cavity and the back surface of the insulating layer forming the protrusion adjacent thereto. In this way, even if the metal layer is formed along the side surface of the cavity and the back surface of the insulating layer that forms the convex portion, the metal plating is performed with a substantially uniform thickness over the entire portion of the metal layer except the upper end portion. The layer can be formed by electrolytic plating.

In the following, the best mode for carrying out the present invention will be described.
1 is a plan view showing a wiring board 1 according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line XX in FIG. 1, and FIG. 3 is a partially enlarged cross-section in FIG. FIG.
As shown in FIGS. 1 and 2, the wiring board 1 has a front surface 3 and a back surface 4 and is made of a ceramic (insulating material) 2. And a cavity 5 in which a diode (light emitting element) 15 is mounted.
As shown in FIGS. 1 and 2, the substrate body 2 has a rectangular parallelepiped shape in a plan view and has a required thickness. For example, a plurality of green sheets mainly composed of alumina are laminated and fired into a ceramic. Is. Incidentally, the size of the substrate body 2 is about 5 mm × 5 mm × 0.9 mm, a wiring layer or via conductor of a predetermined pattern (not shown) mainly composed of W or Mo is formed inside, and the back surface 4 is formed on the back surface 4. A pad (not shown) is formed. For example, glass-ceramic obtained by laminating and firing a plurality of glass-alumina-based green sheets may be applied to the substrate body 2.

As shown in FIGS. 1 and 2, the cavity 5 has a bottom surface 6 that is circular in a plan view and a side surface 7 that is inclined so as to spread from the periphery of the bottom surface 6 toward the surface 3 side of the substrate body 2. It has a truncated cone shape. The elevation angle of the side surface 7 is appropriately selected within a range of 30 to 70 degrees.
The cavity 5 is formed in a substantially conical shape by punching a green sheet with a punch and a die through a required clearance. Incidentally, the size of the cavity 5 is an inner diameter of the upper end of about 3.6 mm × depth of about 0.45 mm.

As shown in FIGS. 1 to 3, a convex portion 8 including the surface 3 of the substrate body 2 on the side surface 7 of the side surface 7 of the cavity 5 faces the center side of the opening of the cavity 5. And projecting in a ring shape. Also, in the cross section perpendicular to the front surface 3 of the substrate body 2, the insulating portion 10 having a curved surface 10 a having a depressed cross section is formed on the entire back surface of the convex portion 8 on the back surface 9 side. Are formed along. The insulating portion 10 having such a curved surface 10 a is obtained by extending a part of the insulating material forming the convex portion 8 toward the bottom surface 6 of the cavity 5. The “extension” means that “the insulating material is extended”.
Further, a metal layer 11 made of W or Mo is formed on the side surface 7 of the cavity 5, and a metal plating layer 12 for reflecting light from the light emitting diode 15 is formed thereon. As shown in FIG. 3, a metal plating layer (hereinafter referred to as a plating layer) 12 includes a Ni plating layer 13 formed on the metal layer 11 and a light reflection Ag plating layer 14 formed thereon. And. The insulating part 10 having the curved surface 10 a covers the upper end part 11 b of the metal layer 11.
The plated layer 12 is formed on the metal layer 11 on the lower side (the back surface 4 of the substrate body 2) than the upper end portion 11b covered with the insulating portion 10, but is not limited thereto, and at least the insulating portion. What is necessary is just to be formed in a part of metal layer 11 except 10 vicinity.
As shown in FIG. 3, the angle between the tangent line s in contact with the vicinity of the center of the curved surface 10 a in the insulating portion 10 and the metal layer 11 is an obtuse angle θ (for example, 110) exceeding 90 degrees. Of the metal layer 11, a horizontal portion 11 a extending from the upper end portion 11 b enters between the ceramic layers s 2 and s 3 constituting the substrate body 2. That is, the ceramic layer that forms the convex portion 8 and the side surface 7 of the cavity 5 is formed by separate ceramic layers s2 and s3 that are laminated together.

As shown in FIGS. 1 and 2, a light emitting diode 15 is mounted on the center of the bottom surface 6 of the cavity 5 via solder or epoxy resin (not shown), and a bottom surface sandwiching the mounting area. 6, a pair of pads 16 are formed symmetrically. The pad 16 is also made of W or Mo. A Ni, Au, or Ag plating layer is formed on the surface of the pad 16 and is individually connected to the light emitting diode 15 via a bonding wire (not shown).
Further, in the cavity 5 in which the light emitting diode 15 is mounted and the pad 16 is connected to the pair of pads 16 through a bonding wire, a solidified seal is formed as shown by a one-dot chain line in FIGS. The stopping resin j is filled up to the position of the back surface 9 of the convex portion 8, for example.

FIG. 4 is a partially enlarged cross-sectional view similar to FIG. 3, showing a different form of the wiring board 1a.
The wiring board 1 a also includes the same substrate body 2, cavity 5 and convex portion 8 as those described above. In addition, an insulating portion 18 having a tapered surface 18 a inclined so as to spread from the front surface 3 of the substrate body 2 toward the back surface 4 side is provided on the back surface 9 side of the convex portion 8 along the entire circumference of the opening of the cavity 5. Is formed. The insulating part 18 having the tapered surface 18 a is a part of the insulating material forming the convex part 8 extending toward the bottom surface 6 side of the cavity 5 and covers the upper end part 11 b of the metal layer 11. The angle between the tapered surface 18a of the insulating portion 18 and the metal layer 11 formed on the side surface 7 of the cavity 5 is an obtuse angle θ (for example, about 100 degrees) exceeding 90 degrees.
Further, a metal layer 11 similar to that described above is formed along the side surface 7 of the cavity 5 and the back surface 9 of the ceramic layer that forms the convex portion 8, and the Ni plating layer 13 and Ag for light reflection are formed on the metal layer 11. A plating layer 12 composed of the plating layer 14 is formed. The upper end portion of the plating layer 12 is located near the lower end portion of the tapered portion 18. As indicated by the one-dot chain line in FIG. 4, the cavity 5 is filled with a sealing resin j.

The wiring boards 1 and 1a as described above were manufactured as follows.
As shown in the cross-sectional view of FIG. 5, green sheets s1 to s3 made of a ceramic material mainly composed of alumina, for example, were prepared in advance. The green sheets s1 to s3 and the ceramic layers s1 to s3 are denoted by a common reference for convenience.
The lowermost green sheet s1 has a flat plate shape having a front surface 6a and a rear surface 4 that are part of the bottom surface 6 of the cavity 5, and has a wiring pattern with a predetermined pattern (not shown) containing W or Mo as a main component. It was a laminate of a plurality of green sheets on which via conductors were formed.
Further, in FIG. 5, the middle-layer green sheet s2 has a substantially frustoconical gold shape in a through hole formed by punching with a punch and a die receiving hole with a required clearance or punching with a minimum clearance. A substantially frustoconical through-hole 17 was formed by pushing the mold. A metal layer 11 containing W or Mo powder was formed on the side surface of the through-hole 17 and the surface of the green sheet s2 adjacent thereto by a known printing method or the like.

5, the uppermost green sheet s3 has a front surface 3 of the substrate body 2 and a back surface 9a to be the back surface 9 of the convex portion 8, and has a flat cylindrical through-hole 19 by punching. It was. The inner diameter of the through hole 19 was smaller than the inner diameter of the upper end portion of the through hole 17 of the green sheet s2. A solvent w such as n-butyl phthalate, castor oil, or n-butyl alcohol was applied to the back surface 9a side of the green sheet s3 so as to penetrate with a required thickness.
After laminating the above green sheets s1 to s3, these were pressure-bonded along the thickness direction. Alternatively, the green sheets s <b> 1 to s <b> 3 were pressure-bonded each time they were stacked in the adjacent order.
As a result, as shown in FIG. 6, the green sheet s3 was laminated on the green sheet (s1) s2, and the substrate body 2 and the cavity 5 were formed. At the same time, a convex portion 8 including the surface 3 of the substrate body 2 and projecting the green sheet s3 toward the center of the opening of the cavity 5 was formed on the side surface 7 of the cavity 5. In addition, the thickness of the convex portion 8 was slightly thicker than the thickness of the green sheet s3 pressure-bonded on the green sheet s2.

Further, as shown in FIG. 6, the ceramic softened by the solvent w receives a pressure accompanying the pressure bonding, so that a part of the ceramic material (insulating material) forming the convex portion 8 is on the bottom surface 6 side of the cavity 5. The upper end portion 11b of the metal layer 11 was covered. As a result, an insulating portion 10 having a curved surface 10a having a concave cross-sectional arc shape in a cross section perpendicular to the surface 3 of the substrate body 2 including the convex portion 8 was formed.
In addition, the penetration depth of the solvent w with respect to the green sheet s3 and the pressure at the time of pressure bonding were adjusted, and a part of the ceramic material forming the convex portion 8 was extended to the bottom surface 6 side of the cavity 5. As a result, the insulating portion 18 having the tapered surface 18a inclined so as to spread from the front surface 3 side to the back surface 4 side of the substrate body 2 could be formed on the back surface 9 side of the convex portion 8.

And after baking the green sheet laminated body obtained by laminating | stacking and crimping | bonding the green sheets s1-s3 in a required temperature range, by applying electrolytic Ni plating and electrolytic Ag plating sequentially, the insulating parts 10 and 18 On the metal layer 11 exposed on the lower side, the plating layer 12 composed of the Ni plating layer 13 and the Ag plating layer 14 was formed.
At the time of each plating described above, the insulating portion 10 having the curved surface 10a or the insulating portion 18 having the tapered surface 18a is formed on the back surface 9 side of the protruding portion 8, and thus the protruding portion 8 of the metal layer 11 is formed on the protruding portion 8. Even in the adjacent portions, each plating solution was smoothly circulated. As a result, as shown in FIGS. 3 and 4, the wiring boards 1 and 1a having the Ni plating layer 13 and the Ag plating layer 14 at the end of the plating layer 12 having substantially the same thickness as the central portion thereof are obtained. I was able to get it.
The “substantially the same thickness” means that the difference in thickness between the end portion and the center portion is within ± 20%. In addition, an obtuse angle θ was formed between the curved surface 10 a or the tapered surface 18 a of the insulating portions 10 and 18 and the metal layer 11 formed on the side surface of the cavity 5.

Further, as shown in FIG. 7, after forming an insulating paste p having a substantially semicircular cross section in a ring shape having a circular shape in plan view outside the through hole 19 in the back surface 9a of the green sheet s3, the green sheet s3 And the green sheets s2 and s1 were laminated and pressure-bonded in the same manner as described above. The insulating paste p contained the same kind of alumina as that of the green sheets s1 to s3, and contained some organic components such as a solvent.
As a result, as shown in the partially enlarged view of FIG. 8, the substrate body 2, the cavity 5, and the convex portion 8 were formed in the same manner as described above.
At the same time, a portion of the ceramic material (insulating material) forming the convex portion 8 is formed between the back surface 9 of the convex portion 8 and the side surface 7 of the cavity 5 due to the pressure accompanying the pressure bonding of the insulating paste p. It extended to the bottom face 6 side (extending). As a result, in the cross section perpendicular to the front surface 3 of the substrate body 2 including the convex portion 8, the insulating portion 18 having the tapered surface 18 a inclined so as to spread from the front surface 3 side to the back surface 4 side of the substrate main body 2. Could be formed.

The insulating portion 10 having the curved surface 10a could be formed on the back surface 9 side of the convex portion 8 by adjusting the cross-sectional shape of the insulating paste p and the pressure during pressure bonding.
Then, after the green sheets s1 to s3 are fired in the same manner as described above, the electrolytic Ni plating and the electrolytic Ag plating are sequentially performed on the metal layer 11 exposed below the insulating portions 10 and 18. The wiring boards 1 and 1a on which the plating layer 12 composed of the Ni plating layer 13 and the Ag plating layer 14 was formed were obtained.
At the time of each plating, the plating solution was smoothly circulated in the portion adjacent to the convex portion 8 of the metal layer 11 by the taper portion 18 or the curved portion 10, and therefore, the Ni plating layer 13 and the Ag plating layer 14. Can be formed with substantially the same thickness as the central part thereof.

According to the wiring boards 1 and 1a as described above, the insulating portion 10 having the curved surface 10a or the insulating portion 18 having the tapered surface 18a is provided on the back surface 9 side of the convex portion 8 including the front surface 3 of the substrate body 2. The upper end portion 11 b of the metal layer 11 formed on the side surface 7 of the cavity 5 is covered, and an obtuse angle θ is formed with the metal layer 11. For this reason, the plating solution can be smoothly circulated during each plating. As a result, on the metal layer 11 provided on the side surface 7 of the cavity 5, the plating layer 12 made of Ni / Ag plating layers 13 and 14 having the same thickness as the central portion at the upper end portion could be reliably formed. . For this reason, since Ni of the underlying Ni plating layer does not precipitate on the surface of the uppermost Ag plating layer 14, the discoloration of the Ag plating layer 14 can be prevented from spreading. Therefore, for a long time, the light from the light emitting diode 15 mounted on the bottom surface 6 of the cavity 5 was efficiently reflected and radiated to the outside.
Moreover, since the convex portion 8 protrudes toward the center of the opening at the opening on the side surface 7 of the cavity 5, the cavity 15 is mounted after the light emitting diode 15 is mounted on the bottom surface 6 of the cavity 5. 5 was filled with the sealing resin j before solidification and solidified. As a result, since the sealing resin j was surrounded by the convex portion 8, it was held in a stable posture without peeling from the cavity 5.

9 is a vertical sectional view showing a wiring board 20 which is a modification of the wiring board 1, and FIG. 10 is an enlarged view of a one-dot chain line portion Y in FIG.
As shown in FIGS. 9 and 10, the wiring substrate 20 is made of ceramic (insulating material), and has a substrate body 22 similar to the substrate body 2 having the front surface 23 and the back surface 24, and the front surface 23 of the substrate body 22. And a cavity 25 having a bottom surface 26 that is circular in a plan view and a cylindrical side surface 27 that stands vertically from the periphery thereof.
As shown in FIGS. 9 and 10, a convex portion 28 including the surface 23 of the substrate body 22 is formed on the side surface 27 of the cavity 25 on the side surface 27 of the cavity 25 toward the center of the opening. It protrudes while presenting its shape. Further, in a cross section perpendicular to the surface 23 of the substrate body 22 including the convex portion 28, a part of the ceramic material forming the convex portion 28 is on the bottom surface 26 side of the cavity 25 on the back surface 29 side of the convex portion 28. By extending, the insulating part 30 which has the curved surface 30a of the recessed circular arc shape is formed.

Further, a metal layer 11 made of W or the like is formed on the side surface 27 of the cavity 25, and a plating layer 12 that reflects light from the light emitting diode 15 mounted near the center of the bottom surface 26 is formed thereon. Yes. As shown in FIG. 10, the plating layer 12 includes a Ni plating layer 13 on the metal layer 11 and an Ag plating layer 14 for light reflection. The upper end portion 11b of the metal layer 11 is covered with an insulating portion 30 having a curved surface 30a.
As shown in FIG. 10, the angle between the tangent line s in contact with the vicinity of the center of the curved surface 30a in the insulating portion 30 and the metal layer 11 is an obtuse angle θ exceeding 90 degrees. The horizontal portion 11 a extending from the upper end portion 11 b of the metal layer 11 enters between the ceramic layers s 3 and s 4 constituting the substrate body 22.
9 and 10, the light emitting diode 15 is mounted on the bottom surface 26 of the cavity 25 in the same manner as described above, and a pair of pads 16 are formed symmetrically on both sides thereof. The pad 16 is also electrically connected to the light emitting diode 15 individually as described above.

Further, in the cavity 25 in which the light emitting diode 15 is mounted and the pair of pads 16 are conducted through bonding wires, a solidified sealing resin as shown by a one-dot chain line in FIG. For example, j is filled up to the position of the back surface 29 of the convex portion 28.
FIG. 11 is a partially enlarged cross-sectional view similar to FIG. 10 showing a wiring board 20a which is a modification of the wiring board 1a. The wiring substrate 20a also includes the same substrate body 22, cavity 25, and convex portion 28 as those described above. Further, on the back surface 29 side of the convex portion 28, an insulating portion 32 having a tapered surface 32 a that is inclined so as to spread from the front surface 23 side to the back surface 24 side of the substrate body 22 is provided around the opening of the cavity 25. Are formed along. The insulating portion 32 covers the upper end portion 11b of the metal layer 11 formed on the side surface 27 of the cavity 25, and the angle between the tapered surface 32a and the metal layer 11 formed on the side surface 27 of the cavity 25 is 90 °. The obtuse angle θ (for example, about 140 degrees) exceeding 60 degrees.

Further, the same metal layer 11 as described above is formed along the side surface 27 of the cavity 25, and the plating layer 12 made of Ni · Ag plating layers 13 and 14 is formed on the metal layer 11. The upper end portion of the plating layer 12 is located near the lower end portion of the insulating portion 32. As in FIG. 9, the cavity 25 is filled with a sealing resin j.
The wiring boards 20 and 20a as described above were also manufactured in the same manner as the manufacturing method including the lamination / crimping process shown in FIGS.

Also with the wiring boards 20 and 20a as described above, the insulating portion 30 having the curved surface 30a or the insulating portion 32 having the tapered surface 32a is formed on the back surface 29 side of the convex portion 28. The circulation of each plating solution was performed smoothly. As a result, on the metal layer 11 provided on the side surface 27 of the cavity 25, the plating layer 12 composed of the Ni / Ag plating layers 13 and 14 having the same thickness as the central portion at the upper end portion could be formed reliably. For this reason, Ni in the underlying Ni plating layer 13 was not deposited on the surface of the uppermost Ag plating layer 14, and the spread of discoloration of the Ag plating layer 14 could be prevented. Therefore, for a long period of time, the light from the light emitting diode 15 mounted on the bottom surface 26 of the cavity 25 can be efficiently reflected and emitted to the outside.
In addition, since the convex portion 28 protrudes along the entire circumference of the opening portion of the side surface 27 of the cavity 25, after the light emitting diode 15 is mounted on the bottom surface 26, the sealing resin j is filled in the cavity 25. Further, when solidified, the sealing resin j was surrounded by the convex portion 8 and thus was not peeled off from the cavity 25 and was stably held.

FIG. 12 is a plan view showing an outline of a wiring board 60 having cavities of different forms, and FIG. 13 is a plan view showing an outline of a wiring board 60a which is a modified form thereof.
As shown in FIG. 12, the wiring board 60 is made of the same ceramic as described above and has a rectangular board body 62 in plan view, and a bottom face 66 having an opening in the surface 63 of the board body 62 and having an oval shape in plan view. And a cavity 65 composed of a substantially frustoconical side surface 67 that inclines so as to expand from the periphery thereof toward the surface 63 side of the substrate body 62. The bottom surface 66 of the cavity 65 is formed with a light emitting diode 15 and a pad (not shown) for electrical connection therewith, and the side surface 67 of the cavity 65 is formed with the plating layer 12 via the metal layer 11 similar to the above. Yes.

  As shown in FIG. 12, at the opening side of the side surface 67 of the cavity 65, a convex portion 68 including the surface 63 of the substrate body 62 protrudes toward the center of the opening. On the back surface of the convex portion 68 facing the cavity 65 side, there is an insulating portion extending toward the bottom surface 66 of the cavity 65 and having a curved surface having an obtuse angle, or an insulating portion having a tapered surface having an obtuse angle. Is provided.

On the other hand, as shown in FIG. 13, the wiring board 60a has an opening on the surface 63 of the board main body 62 similar to the above and an oval bottom surface 66 in plan view and perpendicular to the periphery thereof. And a cavity 65a composed of a long cylindrical side surface 67 standing upright. The light emitting diode 15 and the like are also formed on the bottom surface 66 of the cavity 65a, and the plating layer 12 is formed on the side surface 67 of the cavity 65a with the metal layer 11 interposed therebetween.
As shown in FIG. 13, a convex portion 68 including the surface 63 of the substrate main body 62 projects in the same manner as described above on the opening side of the side surface 67 of the cavity 65a, and on the back surface of the convex portion 68 facing the cavity 65 side a. Is provided with an insulating portion having a curved surface having an obtuse angle similar to the above or an insulating portion having a tapered surface having an obtuse angle.

FIG. 14 is a plan view showing an outline of a wiring board 70 having cavities of different forms, and FIG. 15 is a plan view showing an outline of a wiring board 70a which is a modified form thereof.
As shown in FIG. 14, the wiring board 70 is made of the same ceramic as described above and has a rectangular board body 72 in plan view, and has an opening in the surface 73 of the board body 72 and has a bottom surface 76 in plan view having an elliptical shape. And a cavity 75 composed of a substantially elliptical conical side surface 77 that inclines so as to spread from the periphery thereof toward the surface 73 side of the substrate body 72. The light emitting diode 15 and a pad (not shown) for electrical connection with the light emitting diode 15 are formed on the bottom surface 76 of the cavity 75, and the plating layer 12 is formed on the side surface 77 of the cavity 75 via the metal layer 11.

  As shown in FIG. 14, a convex part 78 including the surface 73 of the substrate body 72 protrudes toward the center side of the opening of the cavity 75 on the surface 73 side of the substrate body 72 on the side surface 77 of the cavity 75. . On the back surface of the convex portion 78 facing the cavity 75 side, there is an insulating portion that extends toward the bottom surface 76 of the cavity 75 and has a curved surface that forms an obtuse angle, or an insulating portion that has a tapered surface that forms an obtuse angle. Is provided.

On the other hand, as shown in FIG. 15, the wiring board 70a has an opening on the surface 73 of the board main body 72 similar to the above and an elliptical bottom surface 76 in the plan view and perpendicular to the periphery thereof. And a cavity 75a composed of an elliptical columnar side surface 77 standing upright. The light emitting diode 15 and the like are also formed on the bottom surface 76 of the cavity 75a, and the plating layer 12 is formed on the side surface 77 of the cavity 75a with the metal layer 11 interposed therebetween.
As shown in FIG. 15, a convex portion 78 including the surface 73 of the substrate main body 72 protrudes on the side surface 77 of the substrate main body 72 on the side surface 77 of the cavity 75a in the same manner as described above. An insulating portion having a curved surface having an obtuse angle similar to the above or an insulating portion having a tapered surface having an obtuse angle is provided on the back surface facing the surface.
The above wiring boards 60, 60a, 70, 70a were also manufactured in the same manner as described above, and the effects similar to those of the wiring boards 1, 1a, 20, 20a were also produced by these.

The present invention is not limited to the embodiments described above.
The ceramic which is an insulating material forming the substrate bodies 2 and 22 and the like may be mainly composed of mullite or aluminum nitride, for example. Alternatively, a glass-ceramic that is a kind of low-temperature fired ceramic may be used. In this case, the metal layer 11, the pad 16, or the like is made of Cu or Ag.
The insulating material for forming the substrate bodies 2 and 22 may be an epoxy resin or the like, and a plurality of resin insulating layers made of, for example, an epoxy resin are sequentially formed on the surface of the resin thin plate or metal thin plate. Alternatively, the cavities may be formed in each of the relatively upper resin insulation layers by a known photolithography technique. The same convex portion is formed on the opening side of the cavity, and the curved portion or the tapered portion is formed at a required position on the back surface of the convex portion, or the tip surface of the convex portion is the same as the above. It may be an inclined surface.

Further, the shape of the cavity is not limited to each of the above-mentioned forms, and it is square or rectangular in plan view, and a conductive paste is filled in an arc shape at these four corners, and a metal layer and light reflecting plating are formed on these side surfaces. A layer may be formed.
In addition to the form located on the entire circumference along the opening of the cavity, the protrusions may be arranged apart from each other at a plurality of locations in the opening of the cavity.
In addition, the wiring board of the present invention has a configuration in which a plurality of cavities are formed on the surface of one wiring board, or a plurality of mounting areas are arranged on the bottom surface of a single cavity, and light emitting elements are individually mounted on these. It is also possible.

The top view which shows the wiring board of one form in this invention. Sectional drawing along the arrow of the XX in FIG. The fragmentary sectional view which expanded the vicinity of the convex part in FIG. The fragmentary sectional view similar to FIG. 3 which shows the wiring board of a different form. Schematic which shows one manufacturing process of each said wiring board. FIG. 6 is a partial schematic diagram illustrating a manufacturing process subsequent to FIG. 5. Schematic which shows one manufacturing process of a different form. FIG. 7 is a partial schematic diagram illustrating a manufacturing process subsequent to FIG. 6. FIG. 3 is a vertical sectional view showing a modified embodiment of the wiring board of FIG. 1. The partial expanded sectional view which shows the dashed-dotted line part Y in FIG. FIG. 11 is a partially enlarged cross-sectional view similar to FIG. 10 showing a modified embodiment of the wiring board of FIG. 4. Furthermore, the top view which shows the wiring board of a different form. The top view which shows the outline of the deformation | transformation form of the said wiring board. The top view which shows the wiring board of another form. The top view which shows the outline of the deformation | transformation form of the said wiring board.

Explanation of symbols

1,1a, 20,20a, 60,60a, 70,70a ... wiring board 2,22,62,72 …………………………………… PCB body 3, 23, 63, 73 ……… ………………………… Front side 4,24 ………………………………………………… Back side 5, 25, 60, 60a, 70, 70a …………… …… Cavity 6, 26, 66, 76 ………………………………… Bottom surface 7, 27, 67, 77 ………………………………… Side surface 8, 28,… …………………………………………… Convex 9, 29 ………………………………………………… Back of convex 10, 10, 30 …… ………………………………………… Insulating part 10a, 30a ………………………………………… Curved surface 11 ………………………… …………………………… Metal layer 11b ……………………………………… …………… Upper end 12 ……………………………………………………… Plating layer 15 ……………………………………………… ......... Light-emitting element 18, 32 ............ ……………………………… Insulator 18a, 32a ………………………………………… Tapered surface θ …………………………………………………………obtuse angle

Claims (4)

A substrate body made of an insulating material and having a front surface and a back surface;
A cavity having an opening on the surface of the substrate body, a bottom surface, a side surface, and a convex portion protruding toward the opening on the surface side of the side surface;
A metal layer formed on the side surface;
On the back side of the convex part, an insulating part that forms an obtuse angle with the metal layer,
A wiring board characterized by that. A substrate body made of an insulating material and having a front surface and a back surface;
A cavity having an opening on the surface of the substrate body, a bottom surface, a side surface, and a convex portion protruding toward the center side of the opening on the side surface;
A metal layer formed on the side surface;
An insulating portion covering at least the upper end portion of the metal layer,
A wiring board characterized by that. The insulating part has a concave curved surface in a cross section perpendicular to the surface of the substrate body.
The wiring board according to claim 1 or 2, wherein The insulating portion has a tapered surface inclined so that the cavity spreads from the front surface side to the back surface side of the substrate main body in a cross section perpendicular to the surface of the substrate main body.
The wiring board according to claim 1 or 2, wherein

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