JP4856558B2 - Wiring board - Google Patents

Description

  The present invention relates to a wiring board having a mounting surface on which a light emitting element such as a light emitting diode is mounted and excellent in heat dissipation of heat generated by the light emitting element.

In order to easily obtain a high-intensity light quantity, an LED element is mounted on the upper surface of a metal or other heat radiating member that penetrates the central portion of the ceramic multilayer substrate, and the upper surface of the multilayer substrate surrounding the LED element is for light reflection. There has been proposed a light emitting device in which a package in which the inclined surface is provided is formed and a mold resin for sealing the LED element is filled inside the package and a manufacturing method thereof (for example, see Patent Document 1).
The heat dissipating member used in the light emitting device effectively dissipates the heat generated by the LED element to the outside, so that the LED element is mounted and the upper part having a small cross-sectional area exposed on the upper surface of the multilayer substrate, and the multilayer substrate. The lower part having a large cross-sectional area exposed on the lower surface of each of them exhibits a rectangular shape or a circular shape similar to each other in plan view.

JP 2006-32804 A (pages 1 to 18, FIGS. 1 and 4)

  However, in the light emitting device, the heat generated by the LED element can be effectively dissipated to the outside. However, since a heat radiating member such as a metal penetrates the central portion of the ceramic multilayer substrate, it is formed inside the multilayer substrate. The layout of the power wiring layer is greatly restricted. For this reason, it becomes difficult to form a required circuit, and the degree of freedom in design decreases. In addition, in order to insert the heat radiating member into the central portion of the multilayer substrate, a process of forming large and small through holes in a plurality of green sheets or setting and brazing the heat radiating members in the through holes is required. Therefore, there is a problem that many complicated manufacturing processes are required.

  The present invention solves the problems described in the background art, includes a ceramic layer having a mounting surface of a light emitting element, can efficiently dissipate heat of the light emitting element, and can easily arrange a required internal wiring layer. It is an object of the present invention to provide a wiring board that can be manufactured in a simple and few process.

Means for Solving the Problems and Effects of the Invention

In order to solve the above-mentioned problems, the present invention uses a ceramic layer having a mounting surface for a light emitting element having a high thermal conductivity, and forms a conductor that can effectively reflect light from the light emitting element on the mounting surface It was designed with the idea in mind.
That is, the wiring board of the present invention (Claim 1) is formed with a ceramic layer having a mounting surface of a light-emitting element and containing a metal component, and an area of two-thirds or more of the ceramic layer on the mounting surface. And a conductor whose surface layer is coated with at least one of an Ag plating film and an Au plating film.
The reason why the area ratio of the conductor is set to more than two-thirds of the mounting surface is that when the area ratio of the conductor is less than two-thirds, the light emitted from the light-emitting element mounted on the mounting surface is efficiently reflected to the outside. This is to prevent such a situation.

  According to this, for example, the light emitting element is mounted on the conductor, and the heat generated by the light emitting element can be reduced by using the ceramic layer having a high thermal conductivity by including a metal component without using a conventional heat dissipation member. Then, heat can be effectively radiated to the outside. Accordingly, since a large voltage can be applied to the light emitting element, the amount of light emission can be further increased. Furthermore, since the substrate body can be formed only by the ceramic layer, a space for a through hole for inserting a heat radiating member is not required as in the prior art, and a required wiring layer can be freely designed inside the ceramic layer. Can be formed. In addition, in order to insert the heat dissipation member in the central portion of the ceramic layer, it is not necessary to form a large and small through hole in a plurality of green sheets, or to set and braze the heat dissipation member in the through hole. Therefore, it is possible to manufacture with relatively simple and few processes.

The ceramic layer containing the metal component contains 5 to 50 wt% of a metal or metal oxide (metal component) powder (average particle size of 10 μm or less) in a ceramic matrix such as alumina. Presents a black color. The metal contained in the ceramic layer is W, Mo, Ag, Cu or the like, and the metal oxide is an oxide such as W, Mo, Ag, or Cu.
The conductor is obtained by coating the surface of a W or Mo metallization layer formed on the mounting surface with an Ag or Au plating layer on the surface via a Ni plating layer. A plurality of such conductors are formed, and the surface layer of one of the conductors is coated with an Ag plating layer, and the light emitting element is mounted and the light is easily reflected. The remaining conductors include an Au plating layer on the surface layer. It is good also as an electrode which coat | covers and wire-bonds with a light emitting element.
Furthermore, the said conductor should be made into two or more, and the total area of these whole should just be 2/3 or more of the said mounting surface.
In addition, the light emitting element includes a semiconductor laser in addition to a light emitting diode (LED), and is mounted on the conductor formed on the mounting surface of the ceramic layer via a brazing material or a resin layer. At this time, a light emitting element may be mounted on each of the plurality of conductors.

In the present invention, the ceramic layer containing the metal component is laminated on the mounting surface side to form a cavity including the mounting surface and a side surface rising from the periphery of the mounting surface, and the metal component is contained. A wiring board (Claim 2) including a ceramic layer having a whiteness greater than that of the ceramic layer is also included.
According to this, the light emitted from the light emitting element mounted on the mounting surface can be reflected to the side surface of the cavity formed in the ceramic layer having high whiteness and radiated to the outside. Alternatively, the light reflected in advance by the Ag plating layer coated on the surface of the conductor formed on the mounting surface, which is the bottom surface of the cavity, can be further reflected on the side surface of the cavity and emitted to the outside. . Therefore, the light of the light emitting element can be emitted more effectively, and the heat generated by the light emitting element can be efficiently radiated to the outside through the ceramic layer containing the metal component.

The cavity has a circular shape in plan view and an overall cylindrical shape or substantially conical shape, an oval shape in plan view and an overall long cylindrical shape or substantially long cone shape, or an elliptical shape in plan view and the entire shape. Forms such as an elliptic cylinder or a substantially elliptic cone are included.
Further, the side surface of the cavity includes a vertical surface that rises vertically from the periphery of the mounting surface that is the bottom surface thereof, and an inclined surface that rises obliquely so as to expand obliquely upward.
Further, a light reflecting layer comprising a W or Mo metallized layer, a Ni plated layer, and an Ag plated layer may be formed on the side surface of the cavity.
Moreover, the ceramic layer containing the metal component has higher thermal conductivity than the ceramic layer having a high whiteness. Such whiteness is measured with a spectrocolorimeter.
In addition, the ceramic layer having a high whiteness is made of alumina or glass-alumina.

In other words, in the present invention, a via substrate is formed between the conductor and the back surface of the ceramic layer containing the metal component, or the inside thereof, along the thickness direction of the ceramic layer. May also be included.
In this case, the heat generated by the light emitting element mounted on the conductor can be radiated to the outside more efficiently. In particular, the via conductor formed along the peripheral side of the ceramic layer containing the metal component can be further improved in heat dissipation by connecting to the terminal formed on the peripheral side of the back surface of the ceramic layer. It becomes.
The via conductor is made of, for example, W or Mo, and one or a plurality of via conductors are formed on the ceramic layer between the conductor on which the light emitting element is mounted and the inside or the back surface of the ceramic layer containing the metal component. It is formed along the formed via hole.

In the following, the best mode for carrying out the present invention will be described.
1 is a plan view showing a wiring board 1a according to an embodiment of the present invention, FIG. 2 is a vertical sectional view taken along line XX in FIG. 1, and FIG. 3 is a partially enlarged view in FIG. It is sectional drawing. As shown in FIGS. 1 and 2, the wiring board 1a is laminated on the front surface 3 and the back surface 4 that are substantially square in plan view, the ceramic layer s1 containing a metal component, and the mounting surface 6 (upper layer) side. A substrate body 2a including a ceramic layer s21 having a whiteness higher than that of the ceramic layer s1 and a cavity 5a opened on the surface 3 is provided.
The ceramic layer s1 contains 5 to 50 wt% of a metal component metal (W or Mo) or metal oxide powder (average particle size of 10 μm or less) in a ceramic such as alumina, and has a black color. The ceramic layer s1 is formed by laminating an upper ceramic layer s13 that forms the mounting surface 6 that is the bottom surface of the cavity 5a, an intermediate ceramic layer s12, and a lower ceramic layer s11 that forms the back surface 4 of the substrate body 2a. Is. When the content of the metal powder is less than 5 wt%, the improvement in thermal conductivity is insufficient. On the other hand, when the content exceeds 50 wt%, a short circuit may occur between wiring layers to be provided. Therefore, the above range was adopted.

The ceramic layer s21 is mainly composed of alumina, has a whiteness higher than that of the ceramic layer s1, and has a surface 3 of the substrate body 2a and a side surface 7a of the cavity 5a. The ceramic layer s1 containing the metal component has a higher thermal conductivity than the ceramic layer s21 having a higher whiteness.
Further, as shown in FIGS. 1 and 2, the cavity 5 a has a substantially circular conical shape in which the bottom surface of the cavity 5 a is a circular mounting surface 6 and rises obliquely from the mounting surface 6 toward the surface 3. Side surface 7a. The mounting surface 6 is an upper surface of the upper ceramic layer s13 in the ceramic layer s1, and the side surface 7a is an inner peripheral surface of a through hole formed in the ceramic layer s21.

As shown in FIGS. 1 and 2, the mounting surface 6 of the cavity 5 a includes a relatively large pad (conductor) 8 a that is substantially circular in plan view and partially broken in a straight line, and the remaining mounting surface 6. Thus, a relatively small pad (conductor) 9a which is adjacent to the linear portion of the pad 8a and has a substantially crescent shape in plan view is formed. The total area of the pads 8a and 9a is two-thirds or more of the mounting surface 6, and the large pad 8a alone is two-thirds or more of the mounting surface 6.
As shown in FIG. 3 in which the vicinity of the pad 9a in FIG. 2 is enlarged, the large pad 8a is obtained by covering the surface of the W or Mo metallized layer 10 with the Ni plating layer 11 and the Ag plating layer 12, and the surface layer of Ag. A light emitting diode (light emitting element: hereinafter referred to as LED) 18 is mounted on the plating layer 12 via a brazing material (not shown).

On the other hand, the small pad 9a is obtained by coating the same metallized layer 10 with the Ni plating layer 11 and the Au plating layer 13 as the surface layer, and is electrically connected to the LED 18 via a bonding wire (not shown). The The surface layer of the pad 9a may be covered with an Ag plating layer 12 instead of the Au plating layer 13.
By the Ag plating layer 12 on the surface layer of the pad 8a (9a) as described above, the light emitted from the LED 18 mounted on the pad 8a which is the central portion of the mounting surface 6 is reflected and emitted from the cavity 5a to the outside. be able to.
A light reflecting layer made of the metallized layer 10, the Ni plating layer 11, and the Ag plating layer 12 may also be formed on the side surface 7a of the cavity 5a.

As shown in FIG. 2, among the ceramic layers s1, a plurality of wiring layers 14 are formed between the uppermost and middle ceramic layers s12 and s13, and between the middle and lowermost ceramic layers s11 and s12, A plurality of wiring layers 15 are formed. A plurality of terminals 16 are formed on the peripheral side of the back surface 4 of the lowermost ceramic layer s11. The wiring layers 14 and 15, the terminal 16, and the pads 8 a and 9 a are connected via via conductors v penetrating the ceramic layers s 11 to s 13.
Furthermore, a plurality of via conductors V extending from the pad 8a on which the LED 18 is mounted to the back surface 4 of the substrate body 2a penetrates through the central portion of the ceramic layer s1 (s11 to s13).
The wiring layers 14 and 15, the via conductors v and V, and the terminal 16 are made of W or Mo as described above. The lower end of the via conductor V may be positioned inside the lowermost ceramic layer s11.

The wiring board 1a was manufactured as follows.
A ceramic slurry was previously prepared by blending alumina powder, a resin binder, a solvent, and the like, and a green sheet for the ceramic layer s21 was manufactured from the ceramic slurry by a doctor blade method. Separately, a ceramic slurry containing 5 to 50 wt% of Mo powder having an average particle size of 10 μm or less with respect to the alumina powder or the like is prepared, and the ceramic layer is subjected to the same method as described above. Three layers of metal component-containing green sheets for s1 were produced.
Next, the green sheet for the ceramic layer s21 is punched with a punch and a die having a receiving hole having an inner diameter larger than the outer diameter of the punch to form a through hole having an inclined inner peripheral surface. Drilled.

On the other hand, a plurality of via holes were formed on a three-layered metal component-containing green sheet by punching at a predetermined position with a small diameter punch and a die with a receiving hole having substantially the same diameter. The via conductors v and V were formed by filling the via hole with a conductive paste containing Mo powder.
Next, the same conductive paste as described above was screen-printed on at least one of the front and back surfaces of the three-layered metal component-containing green sheet to form pads 8a and 9a, wiring layers 14 and 15, and terminals 16. Note that W powder may be used instead of the Mo powder.
Further, from the upper layer side, a green sheet in which through holes having inclined inner peripheral surfaces are formed, and three layers in which pads 8a and 9a, via conductors v and V, wiring layers 14 and 15 and terminals 16 are appropriately formed. The green sheet laminated body which has the said cavity 5a was formed by laminating | stacking one metal component containing green sheet | seat sequentially, and crimping | bonding it.

And after baking the said green sheet laminated body in a predetermined temperature range, Ni plating and either one of Ag and Au plating were coat | covered on the surface of the pads 8a and 9a and the terminal 16. FIG. Note that the metallized layer 10, the Ni plating layer 11, and the Ag plating layer 12 may also be formed on the side surface 7a of the cavity 5a.
As a result, the wiring board 1a provided with the ceramic layers s1, s21, the cavity 5a, the mounting surface 6, the pads 8a, 9a, and the like could be manufactured.
Each of the above steps may be performed in the form of multiple pieces, and then fired in the same manner as described above, and a plurality of wiring boards 1a may be manufactured simultaneously by cutting and dividing the Ag and Au plated ceramic laminate. good.

According to the wiring substrate 1a as described above, the LED 18 is mounted on the pad 8a, and the heat generated by the LED 18 passes through the ceramic layer s1 (s11 to s13) containing the metal component, and the back surface of the substrate body 2a. 4 and heat can be effectively radiated from the side. Further, the heat dissipation can be further promoted by the plurality of via conductors V that penetrate the ceramic layer s1 from the pad 8a and reach the back surface 4 of the substrate body 2a. Along with these, a large voltage can be applied to the LED 18, so that the amount of emitted light can be increased.
On the other hand, the light emitted from the mounted LED 18 can be efficiently reflected on the Ag plating layer 12 on the surface of the pad 8a (9a) and emitted to the outside. If the metallized layer 10, the Ni plating layer 11, and the Ag plating layer 12 are also formed on the side surface 7a of the cavity 5a, the light from the LED 18 can be reflected more efficiently.

  In addition, since the wiring board 1a forms the board body 2a only with the ceramic layers s1 (s11 to s13) and s2, there is no need for a space for a through hole for inserting a heat radiating member as in the prior art. The layers 14 and 15 can be freely formed between the ceramic layers s11 to s13. In addition, it is not necessary to form a through hole for inserting a heat radiating member in the central portion of the ceramic layer s1 in a plurality of green sheets, or to set and braze the heat radiating member in the through hole. Therefore, it is possible to manufacture with simple and few processes.

FIG. 4 is a plan view showing a wiring board 1b of a different form, and FIG. 5 is a vertical sectional view taken along the line YY in FIG.
As shown in FIGS. 4 and 5, the wiring substrate 1b includes a substrate body 2b including a ceramic layer s1 similar to the above and a ceramic layer s22 laminated on the upper layer side.
The ceramic layer s22 on the upper layer side has the surface 3 of the substrate body 2b and the side surface 7b that forms the cavity 5b, and the whiteness is higher than that of the ceramic layer s1, as with the ceramic layer s21. On the other hand, the lower ceramic layer s1 containing the metal component has the back surface 4 of the substrate body 2b and contains the same metal powder of W or Mo as described above, and is hotter than the upper ceramic layer s22. High conductivity.

As shown in FIGS. 4 and 5, the cavity 5b includes a mounting surface 6 that is circular in plan view, and a side surface 7b that stands vertically from the periphery of the mounting surface 6 toward the surface 3 of the substrate body 2b. The whole has a substantially cylindrical shape.
As shown in FIGS. 4 and 5, pads (conductors) 8a and 9a similar to those described above are formed at the center of the mounting surface 6, and the LED 18 is mounted on the large pad 8a and the small pad 9a. As described above, the LED is electrically connected to the LED 18 through a bonding wire.
As shown in FIG. 5, the same via conductors v and V, wiring layers 14 and 15, and terminals 16 are formed in the ceramic layer s <b> 1.

The wiring board 1b could be manufactured by the same method as the wiring board 1a except that a through hole having a side surface 7b was punched into a white green sheet.
Also with the wiring board 1b as described above, like the wiring board 1a, the heat dissipation from the LED 18 is excellent, the light emission amount of the LED 18 is increased, the radiation of the light emitted from the LED 18 is relatively simple. And the effect that it can manufacture with few man-hours can be show | played.
Note that a light reflecting layer including the metallized layer 10, the Ni plating layer 11, and the Ag plating layer 12 may be formed on the side surface 7b of the cavity 5b as well as the pad 8a.

FIG. 6 is a plan view showing a wiring board 1c which is a modification of the wiring board 1a.
The wiring substrate 1c also includes a substrate body 2a composed of the ceramic layer s1 (s11 to s13) and the ceramic layer s21, a cavity 5a, and the like. The wiring board 1c is different from the wiring board 1a in that the mounting surface 6 which is the bottom surface of the cavity 5a has a circular notch 8d in a plan view and a substantially rectangular notch 8d as shown in FIG. A large pad (conductor) 8b having a shape and a small pad (conductor) 9b which is located in the notch 8d and is spaced from the pad 8b and substantially rectangular in plan view is formed. The pads 8b and 9b as a whole occupy two-thirds or more of the area of the mounting surface 6, and the pad 8b alone is two-thirds or more.

The large pad 8b also comprises the same metallized layer 10, Ni plated layer 11, and Ag plated layer 12 as described above, and reflects the light emitted from the LED 18 mounted at the center thereof. Such light is also reflected on the Ag plating layer 12 or the side surface 7a of the cavity 5a and emitted to the outside. On the other hand, the small pad 9b also comprises the same metallized layer 10, Ni plated layer 11, Au plated layer 13 or Ag plated layer 12 as described above, and is electrically connected to the LED 18 by a bonding wire (not shown).
In the wiring board 1b, the pads 8b and 9b may be formed on the mounting surface 6 which is the bottom surface of the cavity 5b.

FIG. 7 is a plan view showing a wiring board 1d which is a different modification of the wiring boards 1a and 1c. The wiring board 1d is composed of the ceramic layer s1 (s11 to s13) and the ceramic layer s21, and includes a substrate body 2c having a front surface 3 and a rear surface that are rectangular in plan view.
As shown in FIG. 7, the substrate body 2c is formed with a cavity 5c composed of an oval mounting surface 6c in plan view and a substantially conical side surface 7c rising obliquely from its periphery. . On the mounting surface 6c, which is the bottom surface of the cavity 5c, a pair of large pads 8c along the major axis direction and a pair of notches 8e provided at both ends along the major axis direction are the same as described above. The pad 9b is formed. The total area of the pads 8c and 9b is two-thirds or more of the mounting surface 6c.

Each pad 8c is composed of the same metallized layer 10, Ni plated layer 11, and Ag plated layer 12, and the pad 9b is the same metallized layer 10, Ni plated layer 11, Au plated layer 13 or Ag plated layer 12 as described above. Consists of.
The light emitted from each LED 18 individually mounted on the pair of pads 8c is reflected by the Ag plating layer 12 of each pad 8c and emitted to the outside.
Note that a light reflecting layer including the metallized layer 10, the Ni plating layer 11, and the Ag plating layer 12 may also be formed on the side surface 7c of the cavity 5c.
The wiring boards 1c and 1d as described above are manufactured in the same manner as the wiring board 1a, and in the same manner as the wiring board 1a, the heat dissipation from the LED 18 is excellent, and the light emission amount of the LED 18 increases accordingly. Thus, it is possible to achieve the effects of light emission from the LED 18 and that it is relatively simple and can be manufactured with a small number of man-hours.
Instead of the cavity 5c of the wiring substrate 1d, a cavity having a long cylindrical side surface standing vertically from the periphery of the mounting surface 6c may be formed.

8 is a plan view showing a further different form of the wiring board 20a, FIG. 9 is a vertical sectional view taken along the line ZZ in FIG. 8, and FIG. 10 is a partially enlarged sectional view in FIG. It is.
As shown in FIGS. 8 and 9, the wiring board 20 a has a substantially square shape in plan view and is composed of ceramic layers s <b> 1 (s <b> 11 to s <b> 13) containing the same metal component as described above. A substrate body 21 having a back surface 24 is provided.
As shown in FIGS. 8 to 10, the mounting surface 23 is formed with a pad 22 that is substantially rectangular in plan view, and a pad 26 that is located in a notch 25 provided on one side and is substantially rectangular in plan view. The total area of the pads 22 and 26 is 2/3 or more of the mounting surface 3. The total area of the pad 22 alone is also more than two-thirds of the mounting surface 23.
As shown in FIG. 10, the large pad 22 is composed of the same metallized layer 10, Ni plated layer 11, and surface Ag plated layer 12, and an LED 18 is mounted near the center via a brazing material (not shown). Is done.

On the other hand, the small pad 26 covers the same metallized layer 10, Ni plated layer 11, surface Ag plated layer 12 or Au plated layer 13, and a bonding wire (not shown) is connected to the LED 18. Through.
As shown in FIG. 9, the same via conductors v and V, wiring layers 14 and 15 and terminals 16 are formed in the ceramic layer s1. As illustrated on the left side of FIG. 9, some of the via conductors V connect between the periphery of the large pad 22 and the terminal 14 formed near the periphery of the back surface 24 of the substrate body 21. Yes.
The wiring board 20a as described above could be manufactured in the same manner as the wiring board 1a and the like except for the step of forming the cavity 5a and the like.

According to the wiring board 20a, the LED 18 is mounted on the pad 22, and the heat generated by the LED 18 is effected to the outside through the ceramic layer s1 (s11 to s13) from the back surface 24 and the side surface of the substrate body 21. Heat dissipation. In addition, since the plurality of via conductors V that penetrate the ceramic layer s1 from the pad 22 and reach the back surface 24 of the substrate body 2 or the terminal 16, the heat dissipation can be further promoted. Along with these, the light emission amount of the LED 18 can be increased.
Further, the light emitted from the mounted LED 18 can be efficiently reflected on the Ag plating layer 12 on the surface of the pad 22 (26) and emitted to the outside.
In addition, since the substrate body 21 is formed only by the ceramic layer s1 (s11 to s13) containing the metal component, the wiring layers 14 and 15 are interposed between the ceramic layers s1 and s2 as compared with the conventional structure in which a heat dissipation member is inserted. Can be formed freely. In addition, it is not necessary to form a through hole for inserting the heat dissipation member in the ceramic layer s1 in the plurality of green sheets or to set and braze the heat dissipation member in the through hole. It is possible to manufacture with few processes.

FIG. 11 is a plan view showing a wiring board 20b which is a modification of the wiring board 20a. The wiring board 20b is also provided with a substrate body 21, wiring layers 14 and 15, via conductors v and V, terminals 16 and the like made of the same ceramic layer s1 as described above.
The wiring board 20b is different from the wiring board 20a in that the mounting surface 23 of the ceramic layer s1 occupies most of the wiring board 20 and has a substantially rectangular pad 27 and a plan view provided near one side of the pad 27. That is, a small pad 28 spaced from the periphery of the notch 27a is formed in the oval notch 27a. The total area of the pads 27 and 28 is 2/3 or more of the mounting surface 23. Note that the total area of the large pad 27 alone is more than two-thirds of the mounting surface 23.
The pad 27 includes the metallized layer 10, the Ni plating layer 11, and the surface Ag plating layer 12 similar to the above, and reflects and emits the light emitted from the LED 18 mounted at the center thereof to the outside. On the other hand, the pad 28 includes the metallized layer 10, the Ni plating layer 11, and the surface Ag plating layer 12 or the Au plating layer 13, and is electrically connected to the LED 18 by a bonding wire (not shown).

FIG. 12 is a plan view showing a wiring board 20c which is a different modification of the wiring board 20a. The wiring board 20c also has the same substrate body 21, wiring layers 14 and 15, and via conductors as the ceramic layer s1. v, V, terminal 16 and the like are provided.
The wiring board 20c is different from the wiring board 20a in that the mounting surface 23 of the ceramic layer s1 occupies two-thirds or more of the large pad 29 having a substantially rectangular shape in plan view and one side of the pad 29. A small pad 30 having a substantially rectangular shape in plan view provided on the mounting surface 23 is formed. The pads 29 and 30 are the same as the pads 27 and 28 of the wiring board 20b.
The wiring boards 20b and 20c can also be manufactured in the same manner as the wiring board 20a, and the same effects as the wiring board 20a can be obtained.
Further, also in the wiring boards 20b and 20c, the via conductor V penetrating the ceramic layer s1 is formed on the peripheral side of the pads 27 and 29, so that the plurality of terminals 16 located on the back surface 24 of the board body 21 are provided. It can be directly connected, and the heat of the LED 18 can be dissipated more efficiently.

In addition, this invention is not limited to each form demonstrated above.
For example, the ceramic layers s1, s21, s22 may be a low-temperature fired ceramic made of glass-alumina. In such a form, the via conductors v, V, the wiring layers 14, 15, and the terminal 16 such as the pads 8a, 9a. May be formed of Ag or Cu, or Ag or Cu powder may be used for the metal component of the ceramic layer s1.
A plurality of light emitting elements may be mounted on the relatively large pads 8a to 8c, 22, 27, and 29. On the other hand, a pair of relatively small pads 9a, 9b, 26, 28, 30 may be formed symmetrically on both sides of one pad 8a or the like. In such a form, the LED 18 is mounted on the pad 8a or the like via a resin layer.
Further, the cavities 5a to 5c of the wiring boards 1a to 1d may be filled and solidified with a light-transmitting sealing resin after the LEDs 18 are mounted on the mounting surfaces 6 thereof.

The top view which shows the wiring board of one form in this invention. FIG. 2 is a vertical sectional view taken along line XX in FIG. 1. The partial expanded sectional view in FIG. The top view which shows the wiring board of a different form. FIG. 5 is a vertical sectional view taken along the line Y-Y in FIG. 4. The top view which shows the deformation | transformation form of the wiring board shown to FIG. The top view which shows the different deformation | transformation form of the wiring board shown to FIG. Furthermore, the top view which shows the wiring board of a different form. FIG. 9 is a vertical sectional view taken along the line ZZ in FIG. 8. The partial expanded sectional view in FIG. The top view which shows the deformation | transformation form of the wiring board shown to FIG. The top view which shows the different deformation | transformation form of the wiring board shown to FIG.

Explanation of symbols

1a to 1d, 20a to 20c …… Wiring boards 6, 6c, 23 …………………… Mounting surface 5a to 5c ………………………… Cavity 7a to 7c …………………… ..... Side 8a-8c, 22, 27, 29 ... Pad (conductor)
9a, 9b, 26, 28, 30 ... Pad (conductor)
12 ... ……………………………… Ag plating layer 13 ………………………………… Au plating layer 18 ………………………………… LED ( (Light emitting element)
v, V ……………………………… Via conductor s1 (s11 to s13) …………… Ceramic layers containing metal components s21, s22 ………………… High whiteness Ceramic layer

Claims (2)

A ceramic layer having a mounting surface of the light emitting element and containing a metal component;
The mounting surface includes a conductor that is formed in an area of two-thirds or more of the mounting surface and has a surface layer coated with at least one of an Ag plating film and an Au plating film,
A wiring board characterized by that. The ceramic layer containing the metal component is laminated on the mounting surface side to form a cavity including the mounting surface and a side surface rising from the periphery of the mounting surface, and the whiteness is higher than the ceramic layer containing the metal component. Has a large ceramic layer,
The wiring board according to claim 1.

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