JP2008294253A - Wiring board for packaging light emitting element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring board for packaging a light emitting element, capable of packaging the light emitting element to the bottom surface of a cavity opened on the surface of a board main body including at least ceramic components and effectively and surely radiating heat generated by the light emitting element. <P>SOLUTION: The wiring board 1a for packaging the light emitting element includes: the board main body 2 provided with a surface 3 and a back surface 4 and composed by laminating a plurality of insulating layers S1-S6 including at least the ceramic components; a cavity 5 opened on the surface 3 of the board main body 2 and provided with a side face 7 and the bottom surface 6 where the light emitting element L is packaged; a light reflecting layer 12 formed on the side face 7 of the cavity 5; heat transmission conductor layers 10 and 11 connected to the inner side face of the light reflecting layer 12 at one end and formed between the plurality of insulating layers S1-S3; and a plurality of heat transmission via conductors V1 and V2 disposed between the heat transmission conductor layers 10 and 11 and the back surface 4 of the board main body 2. The heat transmission via conductors V1 and V2 are connected to a pad 19 formed on the back surface 4 of the board main body 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wiring board for mounting a light emitting element, for example, in which a light emitting element such as a light emitting diode is mounted in a cavity and the heat dissipation characteristics from the cavity are excellent.

In recent years, as the luminance of a light emitting element such as a light emitting diode is increased, the amount of energization is increased and the amount of generated heat is also increased. Therefore, it is required to quickly dissipate heat from the light emitting element. For this reason, for example, in an insulating base made of ceramic, a light emitting element mounting wiring board in which a plurality of penetrating metal bodies are penetrated between a light emitting element mounting portion mounted on the main surface and the opposite main surface is provided. It has been proposed (see, for example, Patent Document 1).
Further, in a substrate body formed by laminating a plurality of insulating layers made of glass-ceramic or the like, a relatively large diameter is provided between the bottom surface on which the light emitting element of the cavity opened on the surface is mounted and the back surface of the substrate body. A wiring board for mounting a light-emitting element in which the via conductor is disposed through is also proposed (for example, see Patent Document 2).

Japanese Unexamined Patent Publication No. 2006-100364 (pages 1 to 15, FIG. 2 (a)) JP 2006-216664 A (pages 1 to 10, FIGS. 7 and 8)

However, as in Patent Document 2, in the wiring board in which the light emitting element is mounted on the bottom surface of the cavity, the heat generated by the light emitting element is not limited to the bottom surface of the cavity that is the mounting surface, but is formed on the side surface of the cavity. Combined with the sealing resin that is transmitted to the light reflecting layer and is filled and solidified in the cavity, it is difficult to dissipate to the outside. For this reason, there existed a problem of reducing the brightness | luminance of the said light emitting element.
Moreover, when a relatively large via conductor is disposed between the bottom surface of the cavity and the back surface of the substrate body as in Patent Document 2, the space for the wiring layer to be formed inside the substrate body is limited. There was also a problem of receiving.

  The present invention solves the problems described in the background art, mounts a light emitting element on the bottom surface of a cavity that opens at least on the surface of a substrate body containing a ceramic component, and effectively generates heat from the cavity from the cavity. It is another object of the present invention to provide a wiring board for mounting a light emitting element that can reliably dissipate heat.

Means for Solving the Problems and Effects of the Invention

In order to solve the above-described problems, the present invention has been conceived in that heat from a light-emitting element mounted on the bottom surface of a cavity is radiated from a light reflecting layer formed on the side surface of the cavity.
That is, a first light-emitting element mounting wiring board according to the present invention (Claim 1) includes a substrate body formed by laminating a plurality of insulating layers having a front surface and a back surface and containing at least a ceramic component, and the substrate body. A cavity having an opening on the surface and a side surface and a bottom surface on which the light emitting element is mounted; a light reflecting layer formed on the side surface of the cavity; and one end connected to the inner side surface of the light reflecting layer; A heat transfer conductor layer formed between the layers, and at least a plurality of heat transfer via conductors disposed between the heat transfer conductor layer and a plurality of insulating layers located near the back surface of the substrate body. It is characterized by.

  According to this, even if heat generated by a light emitting element such as a light emitting diode mounted on the bottom surface of the cavity is transmitted to the light reflecting layer formed on the side surface of the cavity together with light by radiation or the like, such light reflection is performed. One end is connected to the inner surface of the layer, and heat is transferred to the heat transfer conductor layer formed between the plurality of insulating layers. The heat transferred to the heat transfer conductor layer is diffused and dissipated through at least the plurality of insulating layers forming the substrate body via the heat transfer via conductor. For this reason, even if the sealing resin is filled and solidified in the cavity, the heat transmitted to the light reflecting layer does not stay in the cavity and is surely radiated to at least the inside of the substrate body. Therefore, it is possible to guarantee stable light emission over a long period of time without reducing the luminance of the light emitting element.

The ceramic component contained in the insulating layer includes glass-ceramic that can be fired at a relatively low temperature of 1000 ° C. or lower, and glass that can be fired at about 1250 ° C. (SiO ₂ —MnO ₂ —TiO ₂ —MgO—BaO). -ZrO ₂ based glass) - ceramic, or the like high temperature fired ceramic mainly composed of ceramics such as alumina.
The light emitting element includes a light emitting diode (LED), a semiconductor laser (LD), and the like.
Further, the light reflecting layer includes an Ag, Cu, W, or Mo conductor layer formed directly on the side surface of the cavity, a Ni plating layer, an Au plating layer, and Ag, Pt formed sequentially thereon. , Pd, or Rh.
The heat transfer via conductor is made of, for example, Ag, Cu, W, Mo, or an alloy thereof having a diameter of about 0.1 to 0.2 mm.
In addition, the cavity has a substantially conical shape, a substantially long conical shape, a substantially elliptical cone shape, and a rounded corner at each corner, having side surfaces inclined from the periphery of the bottom surface and extending toward the surface of the substrate body. In addition to the substantially quadrangular pyramid shape, the entire shape having a vertical side surface includes a cylindrical shape, a long cylindrical shape, an elliptical column shape, and a substantially quadrangular prism shape in which each corner is rounded.

Further, the present invention includes a light emitting element mounting wiring board (Claim 2) in which the plurality of heat transfer via conductors are connected to the heat transfer conductor layer.
According to this, the heat transferred to the heat transfer conductor layer is reliably transferred to the heat transfer via conductor, and can be reliably radiated to at least the inside of the substrate body via the heat transfer via conductor.
Furthermore, the present invention includes a light emitting element mounting wiring board (Claim 3) in which the heat transfer via conductor is connected to a pad formed on the back surface of the substrate body.
According to this, the heat transferred from the light reflection layer to the heat transfer conductor layer can be radiated to the outside from the pad formed on the back surface of the substrate body via the heat transfer via conductor.
Further, the present invention includes a light emitting element mounting wiring board (Claim 4) in which the other end of the heat transfer via conductor is exposed on the outer surface of the substrate body.
According to this, the heat transferred from the light reflection layer to the heat transfer conductor layer is dissipated to the outside from the other end of the heat transfer conductor layer, and the heat transfer via conductor is used for the substrate body. Since heat is radiated to the outside from the pad on the back side of the substrate body, the heat in the cavity can be radiated more efficiently.

Furthermore, the present invention includes a light emitting element mounting wiring board (Claim 5) in which the plurality of heat transfer via conductors are disposed along the side surface of the cavity in a plan view.
According to this, the heat transferred from the light emitting element to the light reflecting layer by radiation is transmitted to the substrate body via the heat transfer conductor layer and the plurality of heat transfer via conductors disposed along the side surface of the cavity. Heat is radiated to the outside from a pad formed on the back surface of the substrate, or is transferred and diffused to the plurality of insulating layers forming the substrate body. In addition, since no heat transfer via conductor is provided between the bottom surface of the cavity and the back surface of the substrate body, the wiring layer to be formed inside the substrate body can be formed in an arbitrary pattern without being restricted by space. It can also be arranged.
The term “along the side surface of the cavity” refers to a configuration in which a plurality of heat transfer via conductors are arranged at substantially equal intervals along the side surface of the cavity, and further to the center of the bottom surface of the cavity in such a configuration. In addition, it includes both of the forms arranged at symmetrical positions.

In addition, the present invention also includes a light emitting element mounting wiring board (Claim 6) in which the heat transfer via conductor has a linear shape along the thickness direction of the substrate body.
According to this, the heat transferred from the light emitting element to the light reflecting layer is quickly transferred from the pad formed on the back surface of the substrate body to the outside via the heat transfer conductor layer and the linear heat transfer via conductor. Heat dissipation, or heat dissipation and diffusion to the plurality of insulating layers forming the substrate body.
In the heat transfer via conductor having a linear shape, a slightly thick tie pad made of the same material is interposed between a plurality of adjacent insulating layers.

  On the other hand, a second light emitting element mounting wiring board according to the present invention (Claim 7) includes a substrate body having a front surface and a back surface and a plurality of insulating layers including at least a ceramic component, and A cavity having an opening on the surface and having a side surface and a bottom surface on which the light emitting element is mounted, a light reflecting layer formed on the side surface of the cavity, and one end on the inner surface of the light reflecting layer. And a heat transfer conductor layer having the other end exposed at the outer surface of the substrate body.

According to this, even if heat generated by a light emitting element such as a light emitting diode mounted on the bottom surface of the cavity is transmitted together with light to the light reflecting layer formed on the side surface of the cavity by radiation or the like, the light reflecting layer The heat is radiated to the outside through a short path through the heat transfer conductor layer having one end connected to the inner surface and the other end exposed at the outer surface of the substrate body. Therefore, the heat transmitted to the light reflecting layer does not stay in the cavity and is reliably radiated to the outside of the cavity, so that stable light emission can be ensured for a long time without reducing the luminance of the light emitting element. It becomes possible. In addition, between the insulating layers below the bottom surface of the cavity, the wiring layer can be formed in an arbitrary pattern over almost the entire surface, so that high performance can be easily coped with.
The other end of the heat transfer conductor layer may be connected to a heat sink made of Cu or the like formed on the outer surface of the substrate body.

The present invention also includes a light emitting element mounting wiring board (Claim 8) in which a plurality of the heat transfer conductor layers are provided and heat transfer via conductors connecting the heat transfer conductor layers are formed. .
According to this, a part of the heat transferred from the light reflecting layer to the plurality of heat transfer conductor layers is transferred from the heat transfer conductor layer having a low heat transfer speed to the heat transfer conductor layer having a high heat transfer speed. Therefore, the heat in the cavity can be efficiently radiated through the plurality of heat transfer conductor layers.

In other words, in the present invention, a conductor layer that is formed on the bottom surface of the cavity and mounts the light emitting element, or a conductor layer that is energized through the light emitting element and the wire, and formed on the back surface of the substrate body. A wiring board for mounting a light-emitting element, in which a via conductor serving both for conduction and heat transfer is further formed between the terminal pad and the terminal pad, may be included.
In this case, the heat transferred directly or by radiation from the light emitting element to the conductor layer on which the light emitting element is mounted, or to the conductor layer that is energized with the light emitting element, through the via conductor for both conduction and heat transfer, Heat can be radiated to the outside from the terminal pad formed on the back surface of the substrate body. Therefore, it becomes possible to radiate the heat in the cavity more efficiently in combination with the path for radiating heat from the light reflecting layer through the heat transfer conductor layer.
Furthermore, the present invention includes a product region in which any one of the first and second light emitting element mounting wiring boards is disposed adjacent to each other in the vertical and horizontal directions, and at least one side of the product region. A multi-cavity substrate with ears containing the same ceramic component may also be included. In this case, a plurality of the light emitting element mounting wiring boards can be provided simultaneously.

In the following, the best mode for carrying out the present invention will be described.
FIG. 1 is a plan view showing a first light emitting element mounting wiring board (hereinafter simply referred to as a wiring board) 1a according to the present invention, and FIG. 2 is a cross-sectional view taken along the line XX in FIG. FIG.
As shown in FIGS. 1 and 2, the wiring board 1 a includes a substrate body 2 having a front surface 3 and a back surface 4, a cavity 5 having an opening on the surface 3 of the substrate body 2 and having a bottom surface 6 and side surfaces 7, and the cavity 5 The light reflection layer 12 formed on the side surface 7 of the heat transfer, the heat transfer conductor layers 10 and 11 having one end connected to the inner side surface of the light reflection layer 12, and the back surface of the heat transfer conductor layers 10 and 11 and the substrate body 2. 4 are provided with a plurality of heat transfer via conductors V1 and V2. The substrate body 2 is formed by integrally laminating insulating layers S1 to S6 made of, for example, glass-alumina (ceramic), and has a substantially square shape in plan view and a thickness of about 0.7 to 1.0 mm. .

The cavity 5 includes a bottom surface 6 having a circular shape in plan view, and a side surface 7 that inclines from the periphery of the bottom surface 6 toward the surface 3 of the substrate body 2 and has a substantially conical shape as a whole. The elevation angle of the side surface 7 is about 30 to 80 degrees.
On the bottom surface 6 of the cavity 5, a pair of large and small conductor layers 8 and 9 made of Ag, Cu, or an alloy thereof and forming different circuits are formed with a gap therebetween. As shown by the one-dot chain line in FIGS. 1 and 2, a light emitting diode (LED: light emitting element) L is mounted on the large conductor layer 8, and the small conductor layer 9 is electrically connected to the light emitting diode L. A wire 9a for taking a wire is bonded later.
The light reflecting layer 12 formed on the side surface 7 of the cavity 5 is composed of the Ag conductor layer 13 formed directly on the side surface 7 and the Ni formed sequentially thereon as shown in the partial enlarged view in FIG. It consists of a plating layer 14, an Au plating layer (not shown), and a surface Ag plating layer 15.

As shown in FIGS. 1 and 2, one end of a heat transfer conductor layer 10, 11 having a substantially annular shape in plan view formed between the insulating layers S <b> 1 to S <b> 3 is connected to the inner surface of the light reflecting layer 12. Yes. The upper ends or middle portions of the heat transfer via conductors V1 and V2 having a diameter of about 0.1 to 0.2 mm are connected to the plurality of substantially semicircular protrusions protruding from the outer peripheral edges of the heat transfer conductor layers 10 and 11. Has been. The heat transfer via conductors V1 and V2 are also made of Ag, Cu, or an alloy based on one of these.
The plurality of heat transfer via conductors V1 located in the peripheral portion of the substrate body 2 in plan view are individually connected at the upper ends to the heat transfer conductor layer 10 and the insulating layers S2 to S6 are straight along the thickness direction of the substrate body 2. The lower end is connected to the pad 19 formed on the back surface 4 of the substrate body 2 through the shape. The pad 19 is also made of Ag as described above.

The plurality of heat transfer via conductors V2 located inside the heat transfer via conductor V1 are individually connected to the heat transfer conductor layers 10 and 11 at their upper ends and intermediate portions, and at the same position in plan view, the insulating layers S3 to S3. S6 passes through the substrate body 2 in the thickness direction in a straight line shape, and the lower ends thereof are connected to the pads 19 in the same manner as described above.
As shown in FIG. 1, the plurality of heat transfer via conductors V <b> 1, V <b> 2 are arranged at substantially equal intervals along the side surface 7 of the cavity 5 so as to form a substantially circular shape in plan view, and on the bottom surface 6 of the cavity 5. They are arranged symmetrically with respect to the center.
The heat transfer via conductors V1 and V2 are connected between adjacent insulating layers S2 to S6 via a slightly thick tie pad (not shown) made of the same material.

As shown in FIG. 2, between the insulating layers S4 to S6 located between the bottom surface 6 of the cavity 5 and the back surface 4 of the substrate body 2, wiring layers 16 and 18 having a predetermined pattern made of Ag or the like are formed. Yes. Furthermore, a plurality of pads 17 made of Ag or the like are formed on the back surface 4 of the substrate body 2. Between the plurality of pads (terminals) 17, the wiring layers 16 and 18, and the conductor layers 8 and 9 formed on the bottom surface 6 of the cavity 5, a via having a diameter of about 0.1 to 0.2 mm. They are electrically connected to each other through the conductor v. The via conductor v is also made of Ag or the like as described above, and is used for both conduction and heat transfer.
In the peripheral part of the wiring layers 16 and 18, a gap c is formed in a circular shape in plan view that penetrates the heat transfer via conductors V1 and V2 in the central part. In addition, as indicated by a two-dot chain line in FIG. 2, the light emitting diode L is mounted on the conductor layer 8 on the bottom surface 6 of the cavity 5, and the conductor layer 9 adjacent thereto is bonded with a wire 9a. At this time, the sealing resin j before solidification is filled in the cavity 5 up to the vicinity of the surface 3 of the substrate body 2 and is solidified.

  According to the wiring board 1a as described above, heat generated by the light emitting diode L mounted on the bottom surface 6 of the cavity 5 is transmitted to the light reflecting layer 12 formed on the side surface 7 of the cavity 5 by radiation or the like. Then, one end is connected to the inner side surface of the light reflection layer 12 and heat is transferred to the heat transfer conductor layers 10 and 11 formed between the insulating layers S1 to S3. The heat transferred to the heat transfer conductor layers 10 and 11 is radiated to the outside from the pads 19 formed on the back surface 4 of the substrate body 2 through the plurality of heat transfer via conductors V1 and V2. For this reason, even if the sealing resin j is filled and solidified in the cavity 5, the heat transmitted to the light reflecting layer 12 does not stay in the cavity 5 and is reliably radiated to the outside of the substrate body 2. . In addition, the conductive conductor 8 on which the light emitting diode L is mounted and the conductor layer 9 that is energized with the light emitting diode L are directly or radiated from the light emitting diode L, and the via conductor v for both conduction and heat transfer. Further, heat can be radiated to the outside from the pad (terminal) 17 formed on the back surface 4 of the substrate body 2 through the wiring layers 16 and 18. Therefore, it is possible to guarantee stable light emission over a long period of time without reducing the luminance of the light emitting diode L.

The wiring board 1a was manufactured by the following method.
As shown in FIG. 3, green sheets s <b> 1 to s <b> 6 for low-temperature firing containing glass components and ceramic components such as alumina in substantially the same weight are prepared in advance. The glass component is made of borosilicate glass powder containing SiO ₂ , B ₂ O ₃ , and Al ₂ O ₃ as main components. A ceramic slurry obtained by blending such glass powder with alumina powder having an average particle diameter of several μm, a resin binder, a plasticizer, and the like has a front surface 3 and a rear surface 4 that are square in plan view by a doctor blade method. In addition, green sheets s1 to s6 formed into a sheet having a thickness of about 250 μm were obtained.
In addition, instead of the green sheets s1 to s6, a large plate size for multi-piece production for simultaneously producing a plurality of wiring boards may be used.

Next, in FIG. 3, the green sheets s1 to s3 on the upper layer side are punched using a punch and a die having a receiving hole larger than the outer diameter (both not shown), and the inclined inner surface is formed. The through-holes k1 to k3 having them were individually formed.
Further, punching is performed along the positions on the inner and outer double circles in plan view with respect to the green sheets s2 and s3 in which the through holes k2 and k3 are formed and the peripheral portions of the green sheets s4 to s6 on the lower layer side. A plurality of through holes H having an inner diameter of 0.12 mm were formed.
Next, in FIG. 3, punching was performed on a predetermined position on the center side of the green sheets s <b> 4 to s <b> 6 on the lower layer side to form a plurality of through holes h having an inner diameter of 0.12 to 0.25 mm.

Further, as shown in FIG. 4, a conductive paste containing Ag powder is used for each through hole H and each through hole h of the green sheets s2 to s6 using a metal mask and a squeegee (none shown). Filled to form unfired heat transfer via conductors V1, V2 and via conductor v.
Next, the same conductive paste as described above is screen-printed on the surface of the green sheets s2 and s3 on the side of the through holes k2 and k3 to form unfired heat transfer conductor layers 10 and 11 as shown in FIG. did.
Next, the same conductive paste as described above is screen-printed on the front surface of the green sheets s4 to s6 and the back surface of the green sheet s6, and as shown in FIG. , 18 and pads 17, 19 were formed. A plurality of gaps c are formed around the wiring layers 16 and 18.
Note that tie pads (not shown) for connecting the upper and lower heat transfer via conductors V1 and V2 were formed on the surfaces of the green sheets s3 to s6.

Further, as a result of laminating and press-bonding the green sheets s1 to s6 as described above, as shown in FIG. 5, the substrate body 2 having the front surface 3 and the back surface 4, and the unfired having the cavity 5 composed of the bottom surface 6 and the side surface 7 A laminate ss was obtained.
Next, the conductive layer 13 was formed on the entire surface of the side surface 7 of the cavity 5 by screen printing using the same conductive paste as described above using negative pressure.
And after baking the laminated body ss in which the conductor layer 13 was formed in the side surface 7 of the cavity 5, with respect to the conductor layer 13 after baking, electrolytic Ni plating, electrolytic Au plating, and electrolytic Ag plating are performed in order, The light reflecting layer 12 including the Ni plating layer 14 and the Ag surface plating layer 15 was formed. As a result, the wiring board 1a was obtained.
According to the manufacturing method as described above, the wiring board 1a can be reliably manufactured without using a special process or jig. In addition, when the large-sized thing is used for the said green sheets s1-s6, it is also possible to manufacture efficiently the multi-piece substrate 1U mentioned later.

FIG. 6 is a cross-sectional view similar to FIG. 2 showing a first wiring board 1b which is an applied form of the wiring board 1a.
As shown in FIG. 6, the wiring board 1b includes the same substrate body 2, cavity 5, light reflection layer 12, heat transfer conductor layers 10, 11, conductor layers 8, 9, wiring layers 16, 18, and via conductors v. , And a pad 17.
The wiring board 1b is different from the wiring board 1a in that the lower end of the heat transfer via conductors V1 and V2 hanging from the heat transfer conductor layers 10 and 11 forms the lowermost insulating layer forming the back surface 4 of the board body 2. It is to stay between S6 and the insulating layer S5 immediately above it.

That is, the heat transfer via conductors V1 and V2 are disposed between the heat transfer conductor layers 10 and 11 and between the insulating layers S5 and S6, and the lower end thereof is about 0.25 mm from the back surface 4 of the substrate body 2. And the insulating layer S6 thinner than the other insulating layers S1 to S5. In relation to the structure of the heat transfer via conductors V1 and V2, the pad 19 on the back surface 4 of the substrate body 2 is omitted. However, in order to easily dissipate the heat of the heat transfer via conductors V1 and V2 from the back surface 4 side, or to keep the posture when the wiring board 1b is mounted on a mother board such as a printed board (not shown), The heat transfer via conductors V1 and V2 may be provided in the vicinity.
The wiring board 1b can be manufactured by the same method as the wiring board 1a, and can also be manufactured in the same form as the multi-piece substrate 1U described later.

  Also in the wiring substrate 1b as described above, the heat generated by the light emitting diode L mounted on the bottom surface 6 of the cavity 5 is transmitted to the light reflecting layer 12 formed on the side surface 7 of the cavity 5 by radiation or the like. Then, one end is connected to the inner side surface of the light reflecting layer 12 and heat is transferred to the heat transfer conductor layers 10 and 11 formed between the insulating layers S1 to S3. The heat transferred to the heat transfer conductor layers 10 and 11 is radiated and diffused to the insulating layers S2 to S6 of the substrate body 2 through the plurality of heat transfer via conductors V1 and V2. For this reason, even if the sealing resin j is filled and solidified in the cavity 5, the heat transmitted to the light reflecting layer 12 does not stay in the cavity 5 and can be radiated and diffused in the substrate body 2. In addition, the conductor layer 8 on which the light emitting diode L is mounted, or the adjacent conductor layer 9, the heat transferred directly or by radiation from the light emitting diode L, is connected to the via conductor v and the wiring layers 16, 18. The heat can also be radiated to the outside from the pad 17 formed on the back surface 4 of the substrate body 2. Therefore, it is possible to guarantee stable light emission over a long period of time without reducing the luminance of the light emitting diode L.

FIG. 7 is a modification of the wiring boards 1a and 1b and is a cross-sectional view similar to FIG. 2 showing the second wiring board 1c in the present invention.
As shown in FIG. 7, the second wiring substrate 1c includes the same substrate body 2, cavity 5, light reflecting layer 12, heat transfer conductor layers 10, 11, conductor layers 8, 9, wiring layers 16, 18, A via conductor v and a pad 17 are provided.
The wiring board 1c is different from the wiring boards 1a and 1b in that one end of the wiring board 1c is connected to the inner side surface of the light reflecting layer 12 and the heat transfer conductor layers 10 and 11 are formed between the insulating layers S1 to S3. That is, the end e is exposed to the outer surface 2 f of the substrate body 2, and the heat transfer via conductor V <b> 2 is formed only between the heat transfer conductor layers 10 and 11.

In such a wiring board 1c, the heat transfer via conductor V1 is not provided, and the heat transfer via conductor V2 is formed only between the heat transfer conductor layers 10 and 11, so that the wiring layers 16 and 18 are connected between the insulating layers S4 to S6. It can be formed in an arbitrary pattern on almost the entire surface. Accordingly, pads 17 are formed on almost the entire back surface 4 of the substrate body 2.
A heat radiating plate (not shown) made of Cu or the like connected to the other end e may be formed on the outer surface 2f of the substrate body 2 where the other end e of the heat transfer conductor layers 10 and 11 is exposed. . Further, the heat transfer conductor layers 10 and 11 are formed with notches and through holes (not shown) for contacting the insulating layers S1 to S3. Furthermore, the wiring board 1c can also be manufactured by the same method as the wiring board 1a, and can also be manufactured in the same form as the multi-chip substrate 1U described later.

  Also in the wiring board 1c as described above, when the heat generated by the light emitting diode L mounted on the bottom surface 6 of the cavity 5 is transmitted together with the light to the light reflecting layer 12 on the side surface 7 of the cavity 5, the light reflecting layer One end is connected to the inner surface of 12 and heat is transferred to the heat transfer conductor layers 10 and 11 formed between the insulating layers S1 to S3. The heat transferred to the heat transfer conductor layers 10 and 11 is radiated to the outside from the other end e of the heat transfer conductor layers 10 and 11 exposed on the outer surface 2 f of the substrate body 2. That is, the heat is quickly radiated to the outside through a short path for transferring only the heat transfer conductor layers 10 and 11. Further, since the heat transfer via conductor V1 is not provided and the heat transfer via conductor V2 is formed only between the heat transfer conductor layers 10 and 11, the wiring layers 16 and 18 are formed on almost the entire surface between the insulating layers S4 to S6. It is also possible to form with an arbitrary pattern. In addition, the heat transferred directly or by radiation from the light emitting diode L to the conductor layers 8 and 9 on which the light emitting diode L is mounted is connected via the via conductor v and wiring layers 16 and 18 for both conduction and heat transfer. It is also possible to radiate heat from the pad 17 formed on the back surface 4 of the main body 2 to the outside. Therefore, it is possible to guarantee stable light emission over a long period of time without reducing the luminance of the light emitting diode L.

FIG. 8 is a plan view showing a multi-chip substrate 1U having a plurality of wiring boards 1a which are partitioned by a planned cutting line (virtual line) f indicated by a broken line and which are vertically and horizontally adjacent to each other and ears m surrounding these four sides. FIG. Such a multi-piece substrate 1U can be manufactured by the same method as described above, by using the green sheets s1 to s6 as a large plate type.
In the ear m, a plurality of plating electrodes (not shown) having a substantially semicircular plan view are formed in order to form the Ni plating layer 14 and the Ag plating layer 15 of the light reflection layer 12. . Further, as shown in parentheses in FIG. 8, a multi-piece substrate 1U having a plurality of the wiring substrates 1b and 1c in the vertical and horizontal directions may be used.

FIG. 9 is a plan view showing the first wiring board 20a of a different form, and FIG. 10 is a cross-sectional view taken along the line YY in FIG.
As shown in FIGS. 9 and 10, the wiring board 20 a includes a substrate body 22 having a front surface 23 and a back surface 24, a cavity 25 having an opening on the surface 23 of the substrate body 22 and having a bottom surface 26 and side surfaces 27, The light reflection layer 32 formed on the side surface 27, the heat transfer conductor layers 30 and 31 having one end connected to the inner side surface of the light reflection layer 32, and the back surface 24 of the heat transfer conductor layers 30 and 31 and the substrate body 22. A plurality of heat transfer via conductors V1 and V2 disposed between the pad 19 and the pad 19.
The substrate body 22 is formed by integrally laminating insulating layers S4 to S9 made of the same glass-ceramic as described above, has a substantially square shape in plan view, and has a thickness of about 0.7 to 1.0 mm.

Further, as shown in FIGS. 9 and 10, the cavity 25 includes a bottom surface 26 that is circular in plan view, and a side surface 27 that stands vertically from the periphery of the bottom surface 26 toward the surface 23 of the substrate body 22. The whole has a cylindrical shape.
The same conductor layers 8 and 9 are formed on the bottom surface 26 of the cavity 25 through a gap, and a light emitting diode L is mounted on the large conductor layer 8 and the light emitting diode is mounted on the small conductor layer 9. A wire 9a for conducting with L is bonded later.
The light reflecting layer 32 formed on the side surface 27 of the cavity 25 is composed of the Ag conductor layer 33 formed directly on the side surface 27 and the Ni layer formed thereon sequentially as shown in the partial enlarged view of FIG. It consists of a plating layer 34, an Au plating layer (not shown), and a surface Ag plating layer 35.

As shown in FIGS. 9 and 10, one end of the heat transfer conductor layers 30 and 31 having a substantially circular shape in plan view formed between the insulating layers S <b> 7 to S <b> 9 is connected to the inner side surface of the light reflecting layer 32. . The upper ends or intermediate portions of the heat transfer via conductors V1 and V2 similar to the above are connected to a plurality of substantially semicircular protrusions protruding from the outer peripheral edges of the heat transfer conductor layers 30 and 31.
The plurality of heat transfer via conductors V1 positioned in the peripheral portion of the substrate body 22 in plan view are individually connected at the upper ends to the heat transfer conductor layer 30, and the insulating layers S8, S9, and S4 to S6 are connected in the thickness direction of the substrate body 22. The lower end is individually connected to the same pad 19 formed on the back surface 24 of the substrate body 22.
The plurality of heat transfer via conductors V2 located inside the heat transfer via conductor V1 have their upper ends and intermediate portions connected between the heat transfer conductor layers 30 and 31, and the insulating layers S9 and S4 at the same position in plan view. ˜S6 are linearly penetrated along the thickness direction of the substrate body 22 and their lower ends are individually connected to the pads 19 in the same manner as described above.

As shown in FIG. 9, the plurality of heat transfer via conductors V <b> 1 and V <b> 2 are arranged at substantially equal intervals along the side surface 27 of the cavity 25 so as to form a substantially circular shape in plan view, and on the bottom surface 26 of the cavity 25. They are arranged symmetrically with respect to the center.
As shown in FIG. 10, the same wiring layers 16 and 18 are formed between the insulating layers S <b> 4 to S <b> 6 positioned between the bottom surface 26 of the cavity 25 and the back surface 24 of the substrate body 22. On the back surface 24, the same pad 17 is formed. The plurality of pads 17, the wiring layers 16 and 18, and the conductor layers 8 and 9 formed on the bottom surface 26 of the cavity 25 are electrically connected to each other through the same via conductor v. .

As indicated by a two-dot chain line in FIG. 10, the light emitting diode L is mounted on the conductor layer 8 on the bottom surface 26 of the cavity 25, and is bonded to the adjacent conductor layer 9 with a wire 9a. At this time, the sealing resin j before solidification is filled and solidified in the cavity 25 up to the vicinity of the surface 23 of the substrate body 22.
The wiring board 20a can also be manufactured by a method similar to that of the wiring board 1a, in addition to forming a flat cylindrical through hole by punching with a minimum clearance in the green sheets to be the insulating layers S7 to S9. . Further, it can be manufactured in the form of a multi-cavity substrate 20U described later.

  Also by the wiring board 20a as described above, when the heat generated by the light emitting diode L to be mounted is transmitted together with light to the light reflecting layer 32 formed on the side surface 27 of the cavity 25 by radiation or the like, the light reflecting layer One end is connected to the inner side surface of 32 and heat is transferred to the heat transfer conductor layers 30 and 31 formed between the insulating layers S7 to S9. The heat transferred to the heat transfer conductor layers 30 and 31 is radiated to the outside from the pad 19 formed on the back surface 24 of the substrate body 22 through the plurality of heat transfer via conductors V1 and V2. For this reason, even when the sealing resin j is filled and solidified in the cavity 25, the heat transmitted to the light reflecting layer 32 does not stay in the cavity 25 and is reliably radiated to the outside of the substrate body 22. . Moreover, the heat transferred from the light-emitting diode L directly or by radiation to the conductor layer 8 or the like on which the light-emitting diode L is mounted passes through the via conductor v for both conduction and heat transfer and the wiring layers 16 and 18, and the substrate body. It is also possible to radiate heat from the pad 17 provided on the back surface 24 of the outer 22. Therefore, it is possible to guarantee stable light emission over a long period of time without reducing the luminance of the light emitting diode L.

FIG. 11 is a cross-sectional view similar to FIG. 10 showing a first wiring board 20b which is an application form of the wiring board 20a.
As shown in FIG. 11, the wiring board 20b includes the same substrate body 22, cavity 25, light reflection layer 32, heat transfer conductor layers 30, 31, conductor layers 8, 9, wiring layers 16, 18, and via conductors v. , And a pad 17. Furthermore, the thickness of the lowermost insulating layer S6 is made thinner than the other insulating layers S4, S5, S7 to S9.
The wiring board 20b is different from the wiring board 20a in that the lower end of the heat transfer via conductors V1 and V2 hanging from the heat transfer conductor layers 30 and 31 is the lowermost insulating layer forming the back surface 24 of the board body 22. It is to stay between S6 and the insulating layer S5 immediately above it.

That is, the heat transfer via conductors V1 and V2 are disposed between the heat transfer conductor layers 30 and 31 and the insulating layers S5 and S6, and the lower ends thereof are insulated from the back surface 24 of the substrate body 22 with the same thickness as described above. Located above the layer S6. In relation to the structure of the heat transfer via conductors V1 and V2, the pad 19 on the back surface 24 of the substrate body 22 is omitted. However, the heat of the heat transfer via conductors V1 and V2 can be easily radiated from the back surface 24 side. In order to keep the posture when mounting the wiring board 20b on a printed board (not shown) or the like, the pad 19 may be provided in the vicinity immediately below the heat transfer via conductors V1 and V2.
The wiring board 20b can be manufactured by the same method as the wiring board 20a. Further, it can be manufactured in the same form as a multi-piece substrate 20U described later.

  Also in the wiring board 20b as described above, when the heat generated by the light emitting diode L to be mounted is transmitted together with light to the light reflecting layer 32 formed on the side surface 27 of the cavity 25 by radiation or the like, the light reflecting layer. One end is connected to the inner side surface of 32 and heat is transferred to the heat transfer conductor layers 30 and 31 formed between the insulating layers S7 to S9. The heat transferred to the heat transfer conductor layers 30 and 31 is diffused and radiated to the insulating layers S4 to S9 of the substrate body 22 via the plurality of heat transfer via conductors V1 and V2. For this reason, even if the sealing resin j is filled and solidified in the cavity 25, the heat transmitted to the light reflecting layer 32 does not stay in the cavity 25 and is dissipated in the substrate body 22. Moreover, the heat transferred from the light-emitting diode L directly or by radiation to the conductor layer 8 or the like on which the light-emitting diode L is mounted passes through the via conductor v and the wiring layers 16 and 18 for both conduction and heat transfer, and the board body. It is also possible to radiate heat from the pad 17 formed on the back surface 24 of the outside 22. Therefore, it is possible to guarantee stable light emission over a long period of time without reducing the luminance of the light emitting diode L.

FIG. 12 is a cross-sectional view similar to FIG. 10 showing a modified form of the wiring boards 20a and 20b and showing a second wiring board 20c having a different form.
As shown in FIG. 12, the wiring board 20c includes the same substrate body 22, cavity 25, light reflection layer 32, heat transfer conductor layers 30, 31, conductor layers 8, 9, wiring layers 16, 18, and via conductors v. , And a pad 17.
The wiring board 20c is different from the wiring boards 20a and 20b in that one end of the wiring board 20c is connected to the inner surface of the light reflecting layer 32 and the heat transfer conductor layers 30 and 31 are formed between the insulating layers S7 to S9. That is, the end e is exposed to the outer surface 22 f of the substrate body 22, and the heat transfer via conductor V <b> 2 is formed only between the heat transfer conductor layers 30 and 31.

In such a wiring board 20c, the heat transfer via conductor V1 is not provided, and the heat transfer via conductor V2 is formed only between the heat transfer conductor layers 30 and 31, so that the wiring layers 16 and 18 are connected between the insulating layers S4 to S6. It can be formed arbitrarily on almost the entire surface. Accordingly, the pad 17 is formed on almost the entire back surface 24 of the substrate body 22.
In addition, you may form a heat sink similar to the above in the outer surface 22f of the board | substrate body 22 which the other end e of the heat-transfer conductor layers 30 and 31 exposes. Further, the heat transfer conductor layers 30 and 31 are formed with notches and through holes for the insulating layers S7 to S9 to contact. Furthermore, the wiring board 20c can also be manufactured by the same method as the wiring board 20a, and can also be manufactured in the same form as the multi-piece substrate 20U described later.

  Also in the wiring board 20c as described above, when the heat generated by the mounted light emitting diode L is transmitted together with the light to the light reflecting layer 32 on the side surface 27 of the cavity 25, one end is formed on the inner side surface of the light reflecting layer 32. Is transferred to the heat transfer conductor layers 30 and 31 connected to each other. The heat transferred to the heat transfer conductor layers 30 and 31 is radiated to the outside from the other end e of the heat transfer conductor layers 30 and 31 exposed on the outer side surface 22f of the substrate body 22. That is, the heat is quickly radiated to the outside through a short path for transferring only the heat transfer conductor layers 30 and 31. Further, since the heat transfer via conductor V1 is not provided and the heat transfer via conductor V2 is formed only between the heat transfer conductor layers 30 and 31, the wiring layers 16 and 18 are formed on almost the entire surface between the insulating layers S4 to S6. It can also be formed freely. Moreover, the heat transferred from the light-emitting diode L directly or by radiation to the conductor layer 8 or the like on which the light-emitting diode L is mounted is connected to the substrate body via the conductive / heat-transfer via conductor v and the wiring layers 16 and 18. It is also possible to radiate heat from the pad 17 provided on the back surface 24 of the outer 22. Therefore, it is possible to guarantee stable light emission over a long period of time without reducing the luminance of the light emitting diode L.

FIG. 13 is a plan view showing a multi-chip substrate 20U having a plurality of wiring boards 20a partitioned by a planned cutting line (virtual line) f and adjacent in the vertical and horizontal directions and ears m surrounding these four sides. . Such a multi-chip substrate 20U can be manufactured by the same method as described above by using the above-described green sheet as a large plate type.
A plurality of plating electrodes (not shown) having a substantially semicircular plan view are formed on the ear m to form the Ag plating layer 15 and the like of the light reflection layer 32. Further, as shown in parentheses in FIG. 13, a multi-chip substrate 20U having a plurality of the wiring substrates 20b and 20c vertically and horizontally may be used.

FIG. 14 is a cross-sectional view similar to FIG. 6 showing a wiring board 1d of an applied form having both the first and second wiring boards in the present invention.
As shown in FIG. 14, the wiring board 1d has the same substrate body 2, cavity 5, light reflecting layer 12, heat transfer conductor layers 10 and 11, heat transfer via conductors V1 and V2, and conductor layer 8 as the wiring board 1b. , 9, wiring layers 16, 18, via conductors v, and pads 17.
Among these, the heat transfer conductor layer 10 on the upper layer side extends outward between the insulating layers S <b> 1 and S <b> 2, and the other end e is exposed on the outer side surface 2 f of the substrate body 2.
According to the wiring substrate 1d, the heat emitted from the light emitting diode L and transferred from the light reflecting layer 12 to the heat transfer conductor layer 10 is radiated to the outside from the other end e of the heat transfer conductor layer 10. At the same time, the heat is diffused and radiated to the inside of the substrate body via the heat transfer via conductors V1 and V2, so that the heat in the cavity 5 can be radiated more efficiently.
The lower heat transfer conductor layer 11 may also be exposed on the outer surface 2 f of the substrate body 2. Also, the wiring board 1d can be manufactured by the same method as the wiring board 1a. Furthermore, it can also be set as the form similar to the said multi-piece substrate 1U which has several wiring board 1d together. In addition, the heat transfer conductor layers 10 and 11 of the wiring board 1 a may also have their other ends exposed to the outer surface 2 f of the board body 2.

FIG. 15 is a cross-sectional view similar to FIG. 11 showing a wiring board 20d of a different application form having both the first and second wiring boards.
As shown in FIG. 15, the wiring board 20d has the same substrate body 22, cavity 25, light reflection layer 32, heat transfer conductor layers 30, 31, heat transfer via conductors V1, V2, and conductor layer 8 as the wiring board 20b. , 9, wiring layers 16, 18, via conductors v, and pads 17. Among these, the heat transfer conductor layer 30 on the upper layer side extends outward between the insulating layers S <b> 7 and S <b> 8, and the other end e is exposed on the outer surface 22 f of the substrate body 22.
Also by the wiring board 20d, the heat transferred from the light reflection layer 32 to the heat transfer conductor layer 30 is radiated to the outside from the other end e of the heat transfer conductor layer 30 and the heat transfer via is also provided. Since heat is diffused and radiated into the substrate body 22 through the conductors V1 and V2, the heat in the cavity 25 can be radiated more efficiently.
The lower heat transfer conductor layer 31 may also be exposed on the outer surface 22 f of the substrate body 22. Also, the wiring board 20d can be manufactured by the same method as the wiring board 20a. Furthermore, it can also be set as the form similar to the said multi-cavity board | substrate 20U which has several wiring board 20d together. In addition, the heat transfer conductor layers 30 and 31 of the wiring board 20 a may have their other ends exposed to the outer surface 22 f of the board body 22.

The present invention is not limited to the embodiments described above.
The ceramic component contained in the insulating layer may be a high-temperature fired ceramic mainly composed of a ceramic such as alumina. In this case, the materials such as the heat transfer conductor layer, the heat transfer via conductor, the pad, and the wiring layer may be used. W or Mo is applied.
In addition, the cavity has a side surface that is inclined from the periphery of the bottom surface and extends toward the surface of the substrate body, and is generally a long conical shape, a substantially elliptical cone shape, and a substantially quadrangular pyramid with rounded corners. In addition to the shape, the entire shape having a vertical side surface may be a long cylindrical shape, an elliptical column shape, a substantially quadrangular prism shape with rounded corners, and the like.
Further, a plurality of light emitting elements to be mounted on the bottom surface of the cavity may be provided. In such a form, the same number of conductor layers as pairs to which wires are to be bonded are formed.
In addition, an external electrode having a substantially arc-shaped cross section that opens outward is formed at each corner where two adjacent outer surfaces of the substrate body intersect, and the external electrode and a wiring layer inside the substrate body are electrically connected. It is good also as the form which made it possible.

The top view which shows the 1st wiring board in this invention. Sectional drawing along the arrow of the XX in FIG. Schematic which shows the manufacturing process of the said 1st wiring board. Schematic which shows the manufacturing process following FIG. Schematic which shows the manufacturing process following FIG. Sectional drawing similar to FIG. 2 which shows the application form of the said wiring board. Sectional drawing similar to FIG. 2 which shows the 2nd wiring board in this invention. FIG. 3 is a plan view showing a multi-piece substrate having a plurality of the first wiring boards. The top view which shows the 1st wiring board of a different form. Sectional drawing along the arrow of the YY line in FIG. Sectional drawing similar to FIG. 10 which shows the applied form of the wiring board shown to FIG. Sectional drawing similar to FIG. 10 which shows the 2nd wiring board of a different form. FIG. 11 is a plan view showing a multi-chip substrate having a plurality of wiring substrates of FIGS. Sectional drawing similar to the said FIG. 6 which shows the wiring board of the application form which has both 1st and 2nd wiring boards. Sectional drawing similar to the said FIG. 11 which shows the wiring board of the different application form which has the 1st and 2nd wiring board together.

Explanation of symbols

1a to 1d, 20a to 20d ... Light-emitting element mounting wiring board 2, 22 ........... Substrate body 2f, 22f .......... Outer surface 3, 23 ............... …………… Surface 4,24 ………………………… Back 5,25 ………………………… Cavity 6,26 ………………………… Bottom 7, 27 ………………………… Side 10, 11, 30, 31 ……… Heat-conducting conductor layer 12, 32 ……………………… Light reflecting layer 19 …………………… ………… Pads S1 to S9 ……………………… Insulating layer L ………………………………… Light-emitting diode (light-emitting element)
V1, V2 ………………………… Heat transfer via conductor e ………………………………… Other end

Claims (8)

A substrate body formed by laminating a plurality of insulating layers having a front surface and a back surface and containing at least a ceramic component;
A cavity having an opening on the surface of the substrate body and a bottom surface on which a side surface and a light emitting element are mounted;
A light reflecting layer formed on a side surface of the cavity;
One end connected to the inner surface of the light reflecting layer, and a heat transfer conductor layer formed between the plurality of insulating layers;
A plurality of heat transfer via conductors disposed between at least the heat transfer conductor layer and a plurality of insulating layers located near the back surface of the substrate body,
A wiring board for mounting a light-emitting element. The plurality of heat transfer via conductors are connected to the heat transfer conductor layer,
The wiring board for mounting a light emitting element according to claim 1. The plurality of heat transfer via conductors are connected to pads formed on the back surface of the substrate body.
The wiring board for mounting a light emitting element according to claim 1. The other end of the heat transfer conductor layer is exposed on the outer surface of the substrate body.
The wiring board for mounting a light emitting element according to any one of claims 1 to 3. The plurality of heat transfer via conductors are disposed along a side surface of the cavity in a plan view.
The wiring board for mounting a light emitting element according to any one of claims 1 to 4. The heat transfer via conductor has a linear shape along the thickness direction of the substrate body.
The light-emitting element mounting wiring board according to claim 1. A substrate body formed by laminating a plurality of insulating layers having a front surface and a back surface and containing at least a ceramic component;
A cavity having an opening on the surface of the substrate body and a bottom surface on which a side surface and a light emitting element are mounted;
A light reflecting layer formed on a side surface of the cavity;
A heat transfer conductor layer formed between the plurality of insulating layers, having one end connected to the inner side surface of the light reflecting layer and the other end exposed to the outer side surface of the substrate body,
A wiring board for mounting a light-emitting element. There are a plurality of the heat transfer conductor layers, and heat transfer via conductors connecting the plurality of heat transfer conductor layers are formed,
The wiring board for mounting a light emitting element according to claim 1.

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