JP2008109079A - Wiring board for surface mounting type light-emitting element, and light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring board for a surface mounting type light emitting element, along with a light emitting device using the same, of high flexibility in design, being possible to miniaturize, having excellent heat dissipation characteristics. <P>SOLUTION: In a wiring board 11 for a surface mounting type light emitting element, a metal body 5 is arranged in a bottomed hole 3 provided on a flat ceramic insulating base body 1. The metal body 5 and an external connection terminal 13 for mounting the wiring board 11 on an external wiring board are so arranged as vertically stacked in thickness direction at least at a part. So, flexibility in design is high, miniaturizing is possible, and heat dissipation characteristics is excellent. A light emitting device 29 which uses the wiring board 11 can be presented. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a surface mount type light emitting element wiring board and a light emitting device for mounting a light emitting element such as a light emitting diode.

  Conventionally, a light-emitting device using an LED element has been used for various applications because it has a very high luminous efficiency and a small amount of heat is generated with light emission as compared with an incandescent bulb. However, since it emits less light than incandescent bulbs and fluorescent lamps, it is not used for illumination but as a light source for display, and the energization amount is as small as about 30 mA (for example, see Patent Document 1). reference).

  In recent years, with the increase in brightness and whiteness of light-emitting devices using light-emitting elements, light-emitting devices have been frequently used for backlights such as mobile phones and large liquid crystal displays. However, the luminance of the light emitting element is improved and the heat generated from the light emitting device is also increasing. In order to prevent a decrease in luminance of the light emitting element, a wiring board for a light emitting element having high heat dissipation is required (for example, see Patent Document 2).

  Thus, in the wiring board for light emitting elements, heat dissipation is a major issue. By the way, the conventional general semiconductor element which mounts a heat sink on the upper side of a semiconductor element (for example, refer patent document 3), or provides a heat sink on the lower side of a semiconductor element (for example, refer patent document 4) is mounted. It is not easy to apply the heat dissipation structure of a wiring board to be applied to a wiring board for a light emitting element on which an LED element is simply mounted for the following reasons.

  For example, the LED element is very small, 1 mm square or less, so the light-emitting element wiring board on which the element is mounted is also small, and the high-brightness LED device is mounted on various devices such as mobile phones and backlights of liquid crystal displays. Therefore, convenient surface mounting is used as a mounting method.

  For this reason, in the surface mount type light emitting element wiring board, heat from the element is released to the side of the secondary mounting board such as a printed circuit board. (For example, refer to Patent Document 5).

As a means for improving the heat dissipation of the light emitting element wiring board, an example in which a through metal body is provided on the light emitting element wiring board and the light emitting element is mounted on the through metal body has been proposed (for example, Patent Document 6). See).
JP 2002-134790 A JP 2004-111937 A JP-A-8-222668 JP-A-7-254668 JP 2003-318448 A JP 2006-93565 A

  However, although the method of Patent Document 6 can improve heat dissipation by providing a through metal body, there is a problem that the degree of freedom in design is significantly reduced. That is, when the through metal body is not used as an electric circuit, a terminal cannot be provided in a portion where the through metal body is exposed. Therefore, it is necessary to prepare the terminal by avoiding the through metal body. There is no particular problem because the terminal on the light-emitting element side functions sufficiently even if it is small, but on the side where the connection terminal with the external board is provided, it is necessary to radiate heat from the connection part of both, and the area of the external electrode terminal Is required to be increased. Therefore, when a light-emitting element wiring board having a through metal body and a large external electrode terminal is manufactured, there is a problem that the light-emitting element wiring board is necessarily enlarged.

  Further, in the surface mount type light emitting element wiring board, it is difficult to cope with the increasing heat generation because the heat sinks are not always provided on the front and back surfaces.

  An object of the present invention is to provide a wiring board for a surface-mounted light-emitting element that has a high degree of design freedom, can be reduced in size, and is excellent in heat dissipation, and a light-emitting device using the same.

  A wiring board for a surface-mounted light-emitting element according to the present invention includes an insulating base made of ceramics having a bottomed hole having an opening on the upper surface, and a mounting portion for mounting the light-emitting element on the upper surface, and is disposed in the bottomed hole. A metal body, a connection electrode formed on the upper surface of the insulating base, and an external connection terminal formed on the lower surface of the insulating base and electrically connected to the connection electrode, the metal body and the The external connection terminal is characterized in that at least a part of the external connection terminal is vertically overlapped. The connection electrode and the external connection terminal may be electrically connected by an internal wiring formed inside the insulating base, or electrically connected by an external wiring formed on the side wall of the insulating base. It may be.

  The wiring board for a surface-mounted light-emitting element according to the present invention includes an insulating base having a mounting portion for mounting the light-emitting element on the upper surface, a metal body embedded in the insulating base immediately below the mounting portion, and the insulating A connection electrode formed on the upper surface of the substrate; and an external connection terminal formed on the lower surface of the insulating substrate and electrically connected to the connection electrode, wherein the metal body and the external connection terminal are at least one. The parts are arranged so as to overlap each other. Here, it is preferable that an independent metal film is formed on the mounting portion or the connection electrode extends.

  Further, in the wiring board for surface-mounted light-emitting element according to the present invention, the ceramic has a thermal conductivity of 15 W / (m · K) or more, and the thickness of the insulating base between the metal body and the external connection terminal is the same. It is desirable that the thickness is 50 to 200 μm, and 30% or more of the lower surface of the metal body is disposed so as to overlap with the external connection terminal.

  The light emitting device of the present invention is characterized in that a light emitting element is mounted on the mounting portion of the wiring board for a surface mount type light emitting element described above.

  In the wiring board for a surface-mounted light-emitting element according to the present invention, the metal body is disposed in the bottomed hole formed in the insulating base, so that the metal body serves as a heat sink and generates heat generated by the light-emitting element. The light can be discharged to the external substrate through the metal body, the insulating base, and the external connection terminal, and the light emitting element can be prevented from being excessively heated. For this reason, it is possible to prevent the luminance from being lowered or to further increase the luminance.

  Since the insulating base is interposed between the metal body and the external connection terminal, the metal body is not exposed on the lower surface of the surface mount type light emitting element wiring board, and the external connection terminal can be freely designed. Therefore, it contributes to the miniaturization of the surface mounting type light emitting element wiring board, and the wiring design considering the connection reliability and the mounting reliability can also be performed.

  The metal body and the external connection terminal are arranged so that at least part of the metal body and the external connection terminal are vertically stacked with an insulating base interposed in the thickness direction of the surface mount type light emitting element wiring board, whereby the heat generated by the light emitting element is generated. A path from the body to the outside of the system can be formed short, and an excessive temperature rise of the light emitting element can be suppressed.

  Further, the surface mount type light emitting device wiring board of the present invention can freely arrange the connection electrodes and mounting components when the metal body is embedded in the insulating base and the metal body is not exposed on the top surface of the insulating base. Since it can design, it can contribute to size reduction of the wiring board for surface mount type light emitting elements.

  In addition, as a connection electrode formed on the upper surface of the insulating substrate, there is a pair of connection electrodes to which a potential difference is applied. A flip-chip (face-down structure) light-emitting element is mounted, and the electrode terminal of the light-emitting element is connected to each connection electrode. When the metal body is exposed on the upper surface of the insulating base when it is connected to the pair, the pair of connection electrodes to which this potential difference is applied are electrically connected. On the other hand, when the metal body is not exposed on the upper surface of the insulating base, the metal body is not electrically connected to the pair of connection electrodes even if a flip chip type (face-down structure) light emitting element is mounted. It can arrange | position and can acquire sufficient heat dissipation effect.

  When an insulating substrate is interposed between the metal body and the connection electrode, and an independent metal film is formed on the mounting portion or the connection electrode extends, the light emitting element is mounted. The light emitting element and the mounting portion can be bonded using a material having high thermal conductivity. For example, when a metal film plated with Au is formed on the mounting portion, a high heat dissipation effect can be obtained by mounting the light emitting element by AuSn bonding. In addition, since an independent metal film is formed on the mounting portion or the connection electrode extends, light is reflected by the mounting portion, so that an effect of improving light extraction efficiency can be obtained. For example, when Ag plating with high reflectance is applied to the surface, the light extraction efficiency can be improved.

  Furthermore, the surface mount type light emitting element wiring board of the present invention has a thermal conductivity of 15 W / (m · K) or more of the ceramic forming the insulating base, and the thickness of the insulating base between the metal body and the external connection terminal. 50% to 200 μm, and 30% or more of the lower surface of the metal body is arranged so as to overlap the upper and lower external connection terminals, so that there is little influence of the insulating layer that hinders heat conduction, and a higher heat dissipation effect is realized. Can do.

  According to the light-emitting device of the present invention in which the light-emitting element is mounted on the mounting portion of the wiring board for the surface-mounted light-emitting element of the present invention described above, the device can quickly generate heat from the light-emitting element using the metal body and the external connection terminal. Since it can be discharged to the outside, a decrease in luminance due to heat generation can be suppressed, and the degree of freedom in designing the external connection terminal is high, so that downsizing can be realized.

  For example, as shown in FIG. 1A, the surface-mount light-emitting element wiring board of the present invention includes a flat insulating base 1 made of ceramics and a bottomed hole 3 formed in the insulating base 1. ing. A metal body 5 is disposed in the bottomed hole 3, and a mounting portion 7 for mounting a light emitting element is formed above the metal body 5.

  Further, a connection electrode 9 electrically connected to the electrode of the light emitting element mounted on the mounting portion 7 is disposed on the upper surface 1a of the insulating substrate 1, and the surface mounting type of the present invention is disposed on the lower surface 1b of the insulating substrate 1. External connection terminals 13 for electrically connecting the light emitting element wiring board 11 to an external wiring board or the like are arranged.

  In addition, an internal wiring 15 that electrically connects the connection electrode 9 and the external connection terminal 13 is disposed inside the insulating base 1 so as to penetrate the insulating base 1. In the surface mount type light emitting element wiring substrate 11 of the present invention, it is important that the metal body 5 and the external connection terminal 13 are arranged so as to overlap at least partially in the vertical direction.

  That is, when the metal body 5 is embedded in the bottomed hole 3 under the mounting portion 7 of the insulating base 1, heat generated from the light emitting element mounted on the surface mount type light emitting element wiring board 11 of the present invention is generated. By promptly transmitting the light to the metal body 5, it is possible to prevent the temperature of the light emitting element from rising excessively, suppress a decrease in luminance of the light emitting element, and realize higher luminance.

  Further, since the metal body 5 is disposed in the bottomed hole 3, the metal body 5 is not exposed to the lower surface 1 b of the surface mounting type light emitting element wiring substrate 11, so that the wiring design of the external connection terminal 13 is free. Thus, the surface mount type light emitting element wiring substrate 11 can be downsized. In addition, it is easy to design in consideration of mounting reliability. Further, the metal body 5 and the external connection terminal 13 are arranged so as to overlap each other in the thickness direction of the surface mount type light emitting element wiring substrate 11, in other words, a part of the external connection terminal 13 is seen from above. Since it overlaps with the metal body 5, heat generated from the light emitting element and transferred to the metal body 5 with high thermal conductivity is released outside the system through the external connection terminal 13 with high thermal conductivity. It is possible to prevent excessive heat generation of the light emitting element.

  In the surface mount type light emitting element wiring substrate 11 of the present invention, it is desirable that the ratio of the external connection terminals 13 to the lower surface 1b of the insulating base 1 is 45% or more in terms of area ratio. That is, since the external connection terminals 13 occupy a large area, it is possible to achieve high heat dissipation in the surface mounting type light emitting element wiring substrate 11 and at the same time, perform wiring design considering connection reliability and mounting reliability. Is also possible. The area ratio of the external connection terminals 13 is particularly preferably 60% or more.

  Further, it is desirable that 30% or more, further 45% or more, particularly 65% or more of the lower surface of the metal body 5 is disposed so as to overlap the external connection terminal 13 vertically. Thus, by increasing the overlap between the metal body 5 and the external connection terminal 13, the heat dissipation effect of the surface mount type light emitting element wiring substrate 11 can be further enhanced.

  Moreover, it is desirable that the thickness of the insulating base 1 between the metal body 5 and the external connection terminal 13 is 50 to 200 μm. The insulation reliability between the metal body 5 and the external connection terminal 13 can be secured by setting the thickness to 50 μm or more, and the distance from the metal body 5 to the external connection terminal 13 can be shortened by setting the thickness to 200 μm or less. Therefore, the heat radiation path can be shortened. Therefore, the thickness of the insulating substrate 1 between the metal body 5 and the external connection terminal 13 is particularly preferably 60 to 150 μm, and more preferably 80 to 100 μm.

  Further, as the insulating substrate 1, it is desirable to use a material having a thermal conductivity of 15 W / (m · K) or more. Thereby, the heat dissipation of the surface mount type light emitting element wiring substrate 11 can be further enhanced.

  In the surface mount type light emitting element wiring substrate 11 of the present invention, when these requirements are comprehensively provided, that is, the thermal conductivity of the ceramic forming the insulating substrate 1 is 15 W / (m · K) or more, metal Especially when the thickness of the insulating substrate 1 between the body 5 and the external connection terminal 13 is 50 to 200 μm, and 30% or more of the lower surface of the metal body 5 is arranged to overlap the external connection terminal 13 vertically. Excellent heat dissipation effect.

In the case where an Al ₂ O ₃ sintered body having Al ₂ O ₃ as a main crystal phase is used as the insulating base 1, an inexpensive raw material can be used, and an inexpensive surface mount type light emitting element wiring substrate 11 is provided. Obtainable.

Note that the _Al 2 _{O 3} and _Al 2 _{O 3} quality sintered body composed mainly crystalline phase, for example, by X-ray diffraction, is like the peak of _Al 2 _{O 3} is detected as the main peak, Al ₂ It is desirable to contain 50 volume% or more of O ₃ crystals as a volume ratio.

Moreover, such a sintered compact is made of, for example, Al ₂ O ₃ powder having an average particle diameter of 1.0 to 2.0 μm and a purity of 99% or more, and Mn ₂ O ₃ having an average particle diameter of 1.0 to 2.0 μm. , SiO ₂ , MgO, CaO, SrO, a molded body to which at least one kind of sintering aid is added is obtained by firing in a temperature range of 1300 to 1600 ° C.

And, for the addition amount of Al ₂ O ₃ other than the compositions, such as sintering aids, in order to obtain a dense body of the Al ₂ O ₃ as a main crystal, preferably 15 wt% or less, more desirably, 10 It is desirable to set it as the mass% or less. In particular, when the amount of a composition other than Al ₂ O ₃ such as a sintering aid is set to 15% by mass or less, most of the obtained insulating substrate 1 can be formed of Al ₂ O ₃ crystals. . These sintering aids are preferably added in an amount of 5% by mass or more, and more preferably 7% by mass or more in order to lower the firing temperature.

  As the ceramic used for the insulating substrate 1, a sintered body having a main crystal of glass ceramics, magnesium oxide, zirconium oxide, aluminum nitride, silicon nitride, mullite, cordierite, or the like may be used.

  In addition, it is desirable to use a material having higher thermal conductivity than the insulating base 1 as the metal body 5, and the thermal conductivity of the metal body 5 is particularly preferably 150 W / (m · K) or more. Thereby, the effect as a heat sink of the metal body 5 can further be improved, and high heat dissipation can be obtained. Specifically, Cu, Cu—W, Ag, Al, W, Mo, or the like can be used.

  The structure of the metal body 5 may be a rectangular parallelepiped shape, a cylindrical shape, or a multistage shape. When the metal body 5 is a rectangular parallelepiped shape, the volume of the metal body 5 can be maximized, and high heat dissipation is realized. In the case of a cylindrical shape, stress concentration can be prevented and high reliability can be obtained. In the case of a multi-stage shape, since the contact area with the insulating substrate 1 is large, the reliability of bonding with the insulating substrate 1 can be increased.

  Further, a cover land may be provided in parallel with the upper surface 1 a of the insulating base 1 so as to cover the metal body 5. The stress at the interface between the metal body 5 and the insulating substrate 1 is relieved by the cover land, and high reliability can be obtained.

  Further, as shown in FIG. 1B, a frame 17 is provided on the upper surface 1a of the insulating base 1 in order to induce light from the light emitting element mounted on the mounting portion 7 or to protect the light emitting element. May be. The frame body 17 can protect the light emitting element and can easily arrange a phosphor or the like around the light emitting element. Moreover, the light emitted from the light emitting element can be reflected by the frame body 17 and guided in a predetermined direction. The inner wall surface 17a of the frame body 17 may be perpendicular to the upper surface 1a of the insulating substrate 1 or may be inclined. When the inner wall surface 17a of the frame 17 is inclined toward the outside, the light extraction efficiency is further increased.

  The frame 17 may be ceramics or metal, and when the same material as the insulating base 1 is used, high reliability with the insulating base 1 can be obtained, and ceramic or metal of high heat transfer material or high reflectivity material is used. Thus, higher heat dissipation and light extraction efficiency can be obtained.

  Next, the manufacturing method of the surface mount type light emitting element wiring board 11 in the present invention will be specifically described. First, as described below, a ceramic green sheet, a metal sheet, and a conductor paste are prepared.

  The ceramic green sheet is formed on a sheet from a ceramic slurry prepared by mixing ceramic powder, a resin, and a solvent at a predetermined ratio by a conventionally known doctor blade method or the like. The metal sheet is also formed into a sheet shape by a doctor blade method or the like from a metal slurry formed from a metal powder, a resin, a solvent, and the like. The metal slurry may contain ceramic powder as necessary. The ceramic powder used for the ceramic green sheet and the metal sheet, and the particle diameter of the metal powder having an average particle diameter of about 0.01 to 10 [mu] m are preferably used, and in particular, powder in the range of 1 to 5 [mu] m is handled and sintered. Is excellent.

  Desirably, a conductor paste containing at least one of Cu, Ag, W, and Mo as a main component is prepared. By using these metals, it is possible to form the connection electrode 9, the external connection terminal 13 and the internal wiring 15 by simultaneous firing with the insulating base 1, and to obtain an inexpensive surface mount type light emitting element wiring substrate 11. be able to. The conductor paste is produced by mixing metal powder, resin and solvent at a predetermined ratio and removing the solvent by heating under reduced pressure or the like. Ceramic powder may be included as necessary. The average particle size of the metal powder and ceramic powder used for the conductor paste is preferably about 0.01 to 10 μm. Particularly, the powder in the range of 1 to 5 μm is excellent in handling and sinterability. .

  A via hole is formed on the ceramic green sheet by a micro drill, a laser, or the like, and the via hole is filled with a conductor paste by a method such as printing, and the conductor paste is printed on the surface of the ceramic green sheet to form a wiring. And after forming a through hole in a predetermined place of the ceramic green sheet, a metal sheet is laminated on the ceramic green sheet in which the through hole is formed, and a metal is formed by pressing a through hole forming portion in the ceramic green sheet from the metal sheet side. A part of the sheet is embedded in the through hole, and the ceramic green sheet and the metal sheet are integrated. At this time, it is desirable that the ceramic green sheet and the metal sheet have substantially the same thickness.

  Surface mounting in which a plurality of the sheets are laminated and fired in an oxidizing atmosphere, a reducing atmosphere, or an inert atmosphere to form the connection electrode 9, the external connection terminal 13, the internal wiring 15, and the metal body 5 on the surface or inside. Type light emitting element wiring substrate 11 can be manufactured.

  Further, the connection electrode 9 and the external connection terminal 13 may be formed on the surface of the insulating substrate 1 by a thin film method, or may be formed by transferring a metal foil to the surface of the molded body. Alternatively, a pure metal block may be bonded to the baked insulating substrate 1 using solder, silver solder, active solder, or the like.

  A frame 17 as shown in FIG. 1B can be formed by punching a ceramic green sheet, laminating it on the ceramic green sheet of the insulating substrate 1, and performing simultaneous firing. It is also possible to form a metal such as Al or Fe—Ni—Co alloy by cutting or etching into a frame shape and adhere the sintered insulating substrate 1 using a brazing agent or a resin. When bonding using a brazing agent, it is necessary to form a metal layer (not shown) using a metal paste on the bonding surface between the insulating substrate 1 and the frame 17.

  Further, a plating layer (not shown) made of Ni, Au, Al, Ag, or the like is formed on the surfaces of the connection electrode 9, the external connection terminal 13, the metal body 5, and the frame body 17 to increase the reflectance and emit light. You may improve the extraction efficiency of the light which arises from an element.

  Then, for example, as shown in FIG. 2, the light emitting element 21 is mounted on the mounting portion 7 of the above-described surface mount type light emitting element wiring board 11 of the present invention using the connection layer 23 made of metal or resin, A terminal (not shown) of the light emitting element 21 and the connection electrode 9 are connected by a bonding wire 25, and the light emitting element 21, the connection layer 23, and the bonding wire 25 are made of a translucent sealing resin 27 such as a molding material. By covering with, it becomes the light emitting device 29 of the present invention.

  Further, although the light emitting element 21 is covered with the sealing resin 27, the light emitting element 21 may be sealed using a lid (not shown) without using the sealing resin 27. And a lid may be used in combination. As the lid used in this case, it is desirable to use a translucent material such as glass.

  In addition, you may add the fluorescent substance (not shown) for wavelength-converting the light which the light emitting element 21 radiates | emits to this sealing resin 27 as needed.

  Further, from the viewpoint of efficiently transferring the heat of the light emitting element 21 to the metal substrate 11, it is desirable to use a metal such as solder, indium, AuSn alloy as the connection layer 23.

  In the present invention, the heat dissipation is further improved by providing the heat sink. For example, it is not excluded to provide a cooling device such as a heat sink.

  According to the light emitting device 29 of the present invention in which the light emitting element 21 is mounted on the surface mount type light emitting element wiring substrate 11 of the present invention described above, the heat generated from the light emitting element 21 is rapidly generated through the metal body 5 and the external connection terminal 13. Therefore, it is possible to reduce the brightness due to heat generation, and the degree of freedom in designing the external connection terminal 13 is high, so that downsizing can be realized.

  In addition, the electrical connection between the connection electrode 9 and the external connection terminal 13 in the surface mount type light emitting element wiring board of the present invention is not limited to the connection by the internal wiring 15, but as shown in FIG. 16 may be used.

  Further, as shown in FIG. 4B, by providing a cover land in parallel with the upper surface 1a of the insulating base 1 so as to cover the lower surface of the metal body 5 from below, the metal body 5 and the insulating base 1 are In addition to the effect of stress relaxation at the interface, a large amount of heat is transmitted from the metal body 5 to the external connection terminal 13, and the effect of further improving heat dissipation can be obtained.

  In the embodiment described so far, the metal body 5 is exposed on the upper surface 1 a of the insulating base 1. However, as shown in FIG. 5A, the metal body 5 is embedded in the insulating base 1 immediately below the mounting portion 7. The insulating substrate 1 may be interposed between the metal body 5 and the connection electrode 9. In this case, the metal body 5 is not exposed to the upper surface 1a of the insulating base 1, and there are no restrictions on the shape of the connection electrode 9 and the arrangement of mounting parts other than the light emitting element 21, and the degree of freedom in design increases. That is, it can contribute to the miniaturization of the surface mount type light emitting element wiring board. In this embodiment, the mounting portion 7 is within the range of the cross section of the metal body 5 when viewed from above, in other words, the outer periphery of the cross section viewed from the top of the metal body 5 is located outside the mounting portion 7. preferable. Here, the mounting portion 7 means a region on the upper surface 1a of the insulating base 1 where the light emitting element 21 is mounted, in other words, an upper surface region of the insulating base 1 that overlaps the light emitting element 21 when viewed from above.

  Then, as shown in FIG. 5B, a pair of connections are provided even when a flip-chip type (face-down structure) light-emitting element is mounted by embedding a metal body 5 inside the insulating substrate 1. Since the metal body can be disposed without electrically connecting the electrodes, a sufficient heat dissipation effect can be obtained. That is, as the connection electrodes formed on the upper surface of the insulating substrate, there are a pair of connection electrodes to which a potential difference is applied. A flip chip type (face-down structure) light-emitting element is mounted, and the electrode terminals of the light-emitting elements are connected to the respective connection electrodes. When the metal body is exposed on the upper surface of the insulating base when it is connected to the pair, the pair of connection electrodes to which this potential difference is applied are electrically connected. On the other hand, when the metal body is not exposed on the upper surface of the insulating base, the metal body is not electrically connected to the pair of connection electrodes even if a flip chip type (face-down structure) light emitting element is mounted. It can arrange | position and can acquire sufficient heat dissipation effect.

  At this time, the thickness of the insulating base 1 between the metal body 5 and the connection electrode 9 (distance from the upper surface of the metal body 5 to the upper surface 1a of the insulating base 1) is between the metal body 5 and the external connection terminal 13. Similar to the thickness of the insulating substrate 1, it is desirable that the thickness is 50 to 200 μm, particularly 60 to 150 μm, and more preferably 80 to 100 μm from the viewpoint of insulation and heat dissipation.

  Further, in the case where the insulating substrate 1 is interposed between the metal body 5 and the connection electrode 9 and when the independent metal film 8 is formed on the mounting portion 7 or the connection electrode 9 extends. When the light emitting element 21 is mounted, the light emitting element 21 and the mounting portion 7 can be joined using a material having high thermal conductivity.

  Here, the connection electrode 9 is extended to the mounting portion 7, as shown in FIG. 6A, one of the pair of connection electrodes 9 shown in FIG. It means that the connection electrode 9 is formed in the entire region of the mounting portion 7 so as to extend in a direction parallel to 1a. Further, the independent metal film 8 is formed on the mounting portion 7 as shown in FIG. 6B. The metal film 8 that is not electrically connected to the connection electrode 9 is formed on the entire mounting portion 7. It means that it was formed in the region.

  For example, when the metal film 8 plated with Au is formed on the mounting portion 7, a high heat dissipation effect can be obtained by mounting the light emitting element 21 by bonding using an AuSn alloy. Further, since the independent metal film 8 is formed on the mounting portion 7 or the connection electrode is extended, the light is reflected by the mounting portion 7, so that the light extraction efficiency can be improved. . For example, when Ag plating with high reflectance is applied to the surface, the light extraction efficiency can be improved.

Al ₂ O ₃ powder having a purity of 99% or more and an average particle size of 1.5 μm, SiO ₂ powder having a purity of 99% or more and an average particle size of 1.0 μm Using a Mn ₂ O ₃ powder having a purity of 99% or more and an average particle size of 1.5 μm, 90% by mass of Al ₂ O ₃ powder, 5% by mass of SiO ₂ powder, and 5% by mass of Mn ₂ O ₃ powder are mixed for molding. A slurry was prepared by mixing an acrylic binder as an organic resin (binder) and toluene as a solvent. Thereafter, a ceramic green sheet was prepared by a doctor blade method.

  Moreover, as a raw material powder of the metal sheet, W and Cu having an average particle size of 2.0 μm are mixed, 30% by mass of Cu powder and 70% by mass of W powder are mixed, an acrylic binder as a molding organic resin (binder), Toluene was added as a solvent, and a metal sheet having a thickness substantially the same as that of the ceramic green sheet was prepared by a doctor blade method after adjusting the slurry to be a metal sheet in the same manner as the ceramic green sheet.

  Also, a conductor paste was prepared by mixing 30% by mass of Cu powder having an average particle diameter of 2 μm, W powder having an average particle diameter of 2 μm, an acrylic binder and acetone, and removing the solvent by heating under reduced pressure or the like.

  Then, the ceramic green sheet as the insulating base is punched to form a via hole having a diameter of 100 μm. The via hole is filled with a conductor paste by a screen printing method and printed in a wiring pattern. Applied.

  Next, a through hole is formed in a predetermined portion of the ceramic green sheet, and a part of the metal sheet is embedded in the through hole by pressing a through hole forming portion of the ceramic green sheet from the metal sheet. And integrated.

  The composite of the ceramic green sheet and metal sheet thus prepared, and the ceramic green sheet were combined, aligned, and laminated and pressed to produce a laminate.

  Then, after degreasing in a nitrogen-hydrogen mixed atmosphere at a dew point of + 25 ° C., the substrate is subsequently baked at a maximum temperature of 1300 ° C. for 2 hours in a nitrogen-hydrogen mixed atmosphere at a dew point of + 25 ° C. Produced. The thickness of the connection electrode and the external connection terminal was 20 μm.

  Subsequently, Ni, Au, and Ag plating were sequentially performed on the surface of the metal body exposed on the upper surface of the connection electrode, the external connection terminal, and the insulating base.

  The shapes of the surface-mounted light-emitting element wiring board of the present invention and the surface-mounted light-emitting element wiring board outside the scope of the present invention will be described with reference to the following description and FIG.

  FIG. 3 is a plan view of the fabricated surface-mount light-emitting element wiring board as viewed from below, and FIG. 3A is the surface-mount light-emitting element wiring board of the present invention. (B) and (c) are samples prepared as comparative examples. That is, FIG. 3B is a view showing a sample in which the metal body and the external connection terminal do not overlap in the thickness direction of the surface mounting type light emitting element wiring board, and FIG. It is a figure of a sample. 3A and 3B, the circle indicated by the wavy line indicates the position of the metal body provided on the surface mount type light emitting element wiring board.

  In all the samples, two external connection terminals 13 are formed in parallel so as to run vertically from one side of the insulating base to the other side facing each other. The width W of the external connection terminal 13 is shown in Table 1. It changed as shown in. The distance G between the two external connection terminals 13 was also changed as shown in Table 1.

  Table 1 shows the ratio of the area of the external connection terminal to the lower surface of the insulating base as S1, and the area where the metal body and the external connection terminal overlap is relative to the cross-sectional area of the metal body viewed from above. The overlapping ratio is shown as S2.

  The produced surface mount type light emitting element wiring board is a metal body of the same size arranged in a bottomed hole having a diameter of 1.8 mm and a thickness of 0.4 mm provided on a 4 mm × 4 mm plate-like insulating base, The thickness is 0.4 mm plus the thickness of the insulating base between the metal body and the external connection terminals described in Table 1. The thermal conductivity of the insulating substrate was 16 W / (m · K). Further, a frame body having a width of 0.4 mm and a thickness of 0.3 mm was disposed on the mounting portion side along the end of the insulating base.

  In addition, sample No. in Table 1 For No. 11, the same insulating base thickness as the insulating base thickness between the metal body and the external connection terminals was provided between the metal body and the connection electrode. Therefore, the shape of the hole was a covered bottom hole.

  An LED chip, which is a light emitting element with an output of 1.5 W, is mounted on the mounting portion of these surface mount type light emitting element wiring boards using epoxy resin as an adhesive, and the LED chip and the connection terminal are connected by a bonding wire to emit light. A device was made.

The obtained light-emitting device was mounted on an organic substrate with solder, a current of 0.4 A was passed through the light-emitting device, and the element temperature was measured after 1 minute. The results are shown in Table 1.

  According to Table 1, sample no. In 1, the temperature of the light emitting element rose to 86 ° C. because there was only air in the lower part of the metal body. In addition, although the metal body is disposed in the bottomed hole, the sample No. in which the metal body does not overlap the external connection terminal. In No. 2, the heat transfer path became longer, and the temperature of the light emitting element rose to 88 ° C. When the temperature of the light-emitting element exceeds 80 ° C., the light emission efficiency is considerably lowered, so that it is required to be suppressed to 80 ° C. or less.

  On the other hand, the sample No. of the present invention in which a metal body is arranged in the bottomed hole and a part of the external connection terminal overlaps the metal body as viewed from above. 3 to 10 and Sample No. in which a metal body was embedded immediately below the mounting portion inside the insulating substrate. 11, the temperature rise of the light emitting element could be suppressed to 80 ° C. or less.

  As described above, according to the present invention, the degree of freedom in designing the surface-mount light-emitting element wiring board can be improved, and the surface-mount light-emitting element wiring board excellent in heat dissipation and the use thereof A light emitting device can be provided.

(A) is sectional drawing of the wiring board for surface mount type light emitting elements of this invention, (b) is sectional drawing of the wiring board for surface mount type light emitting elements of this invention which provided the frame. (A) is sectional drawing of the light-emitting device of this invention, (b) is sectional drawing of the light-emitting device of this invention which provided the frame. (A) is the top view which looked at the wiring board for surface mount type light emitting elements of this invention from the bottom, FIG.3 (b), (c) is the wiring board for surface mount type light emitting elements of a comparative example below. It is the top view seen from. (A) is sectional drawing of other embodiment of the wiring board for surface mount type light emitting elements of this invention, (b) is another embodiment of the wiring board for surface mount type light emitting elements of this invention. It is sectional drawing. (A) is sectional drawing of other embodiment of the surface mounting type light emitting element wiring board of this invention, (b) is a flip chip type light emitting element in the surface mounting type light emitting element wiring board of this invention. It is sectional drawing of the light-emitting device of this invention which mounted | wore. (A) is sectional drawing of other embodiment of the light-emitting device of this invention, (b) is sectional drawing of other embodiment of the light-emitting device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Insulating base | substrate 1a ... Upper surface 1b of an insulating base | substrate ... Lower surface 3 of an insulating base | substrate ... Bottom hole 5 ... Metal body 7 ... Mounting part 8 ... Independent metal film 9 ... Connecting electrode 11 ... Surface-mount type light emitting element wiring board 13 ... External connection terminal 15 ... Internal wiring 16 ... External wiring 21 ... Light emitting element 29 ... Light emitting device

Claims (6)

An insulating base made of ceramics having a bottomed hole having an opening on the upper surface, a mounting portion for mounting a light emitting element on the upper surface, a metal body disposed in the bottomed hole, and formed on the upper surface of the insulating base A connection electrode and an external connection terminal formed on the lower surface of the insulating base and electrically connected to the connection electrode, wherein the metal body and the external connection terminal are at least partially overlapped with each other. A wiring board for a surface-mounted light-emitting element, which is arranged. 2. The surface mount type light emitting element wiring board according to claim 1, wherein the connection electrode and the external connection terminal are electrically connected by an internal wiring formed in the insulating base. An insulating base made of ceramics having a mounting portion for mounting a light emitting element on the upper surface; a metal body embedded in the insulating base immediately below the mounting portion; a connection electrode formed on the upper surface of the insulating base; An external connection terminal formed on the lower surface of the insulating base and electrically connected to the connection electrode, wherein the metal body and the external connection terminal are arranged so that at least a part thereof overlaps vertically; A surface mount type light emitting device wiring board characterized by the above. The surface mount type light emitting element wiring board according to claim 3, wherein an independent metal film is formed on the mounting portion or the connection electrode extends. The ceramic has a thermal conductivity of 15 W / (m · K) or more, the thickness of the insulating base between the metal body and the external connection terminal is 50 to 200 μm, and 30% or more of the lower surface of the metal body The wiring board for a surface-mounted light-emitting element according to any one of claims 1 to 4, wherein the wiring board is disposed so as to overlap with the external connection terminal. A light emitting device comprising a light emitting element mounted on the mounting portion of the wiring board for a surface mount type light emitting element according to any one of claims 1 to 5.

Images