JP2012074478A - Substrate for light emitting element, and light emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate for light emitting element having a configuration capable of securing economic advantage and flatness as compared to a thermal via, and capable of exhibiting sufficient heat dissipation together with another configuration of a light emitting device when forming the light emitting device.SOLUTION: The substrate for light emitting element includes: a substrate main body, composed of an inorganic insulation material, having a portion of a wiring conductor on a principal plane for mounting a light emitting element so as to electrically connect the electrode of the light emitting element to the wiring circuit of a mother board; on the side face of the substrate main body in the area in which heat generated by the light emitting element conducts, a first heat radiation layer composed of a first heat radiation material and formed in a manner to be disposed from the principal plane side to the opposite plane side, so as to become a fixed portion when solder fixed on the mother board; and on the principal plane of the substrate main body, a second heat radiation layer composed of a second head radiation material, at least including the mounting portion of the light emitting element and formed in a manner to be electrically insulated from a portion of the wiring conductor and to be connected to the first heat radiation layer.

Description

  The present invention relates to a light-emitting element substrate and a light-emitting device using the same, and more particularly to a light-emitting element substrate configured to reduce thermal resistance when the light-emitting device is used, and a light-emitting device using the same.

  2. Description of the Related Art In recent years, light-emitting devices using light-emitting diode elements are used for backlights of mobile phones and large liquid crystal TVs as light-emitting diode elements become brighter and whiter. However, since the amount of heat generation increases with the increase in luminance of the light emitting diode element, and the temperature rises excessively, sufficient light emission luminance cannot always be obtained. Therefore, a substrate for a light-emitting element for mounting a light-emitting element such as a light-emitting diode element is required to be able to quickly dissipate heat generated from the light-emitting element and obtain sufficient light emission luminance.

  Conventionally, a substrate made of an inorganic insulating material such as alumina, aluminum nitride, low temperature co-fired ceramics (hereinafter referred to as LTCC) (hereinafter referred to as “ceramic substrate”) has been used as the light emitting element substrate. In these ceramic substrates, although there is a difference in the thermal conductivity depending on the ceramic material, the situation where the improvement of the heat dissipation is required is the same, and the improvement of the heat dissipation according to the thermal conductivity for each material. Techniques for methods have been developed.

  For example, since an LTCC substrate does not necessarily have a high thermal conductivity, it is known to provide a thermal via made of a high thermal conductive material such as metal to reduce thermal resistance. As thermal vias, for example, those having a plurality of smaller ones than the light emitting element and those having only one having a size substantially the same as the light emitting element are known (see, for example, Patent Document 1).

  In addition, in Patent Document 2, in a light emitting device having a reflective layer such as silver or a silver alloy on a substrate, the reflective layer contributes to heat radiation in the plane direction of the substrate, in addition to heat radiation by the reflective layer. There is a description that it is preferable to provide a heat dissipation via in order to improve heat dissipation in the direction perpendicular to the substrate.

  Here, as a means to dissipate the heat generated from the light emitting element, the heat dissipation layer parallel to the light emitting element mounting surface is economically superior to the thermal via, but the heat dissipation layer alone parallel to the mounting surface is independent of the thermal via. An LTCC substrate for a light emitting element that has an equivalent and sufficient heat dissipation property has not been obtained. Further, the thermal via is not only disadvantageous in terms of cost, but also has a problem that it deteriorates flatness and adversely affects the adhesion between the light emitting element and the substrate.

  On the other hand, in Patent Document 3, a conductor layer is formed in a through hole provided at the intersection of break grooves of a multi-piece ceramic substrate, and this is used as a wiring conductor that is electrically connected from the electrode of the light emitting element to the electrical circuit of the motherboard. Attempts have been made to use it. In addition, in this ceramic substrate, when it is set as each light emitting element substrate, it is the structure by which the conductor layer derived from the said through-hole was formed in the four corners of a board | substrate. The structure of the wiring conductor that electrically connects the electrode of the light emitting element to the electrical circuit of the mother board, that is, the heat generated by the light emitting element is conducted to the mother board by utilizing the four corners of the substrate and used for heat dissipation. However, it is impossible to obtain a light emitting element having sufficient heat dissipation equivalent to a thermal via.

Japanese Patent Laid-Open No. 2006-41230 JP 2010-34487 A JP 2009-10103 A

  The present invention has been made to solve the above-described problems, and has a configuration that is economically advantageous and can ensure flatness as compared with a thermal via, and when combined with other configurations of a light-emitting device. It is an object of the present invention to provide a light emitting element substrate that can exhibit sufficient heat dissipation. Another object of the present invention is to provide a light-emitting device that uses the substrate for a light-emitting element and has excellent heat dissipation.

  A substrate for a light emitting device of the present invention is a substrate body made of an inorganic insulating material having a part of a wiring conductor for electrically connecting an electrode of the light emitting device to a wiring circuit of a motherboard on a main surface on which the light emitting device is mounted. And a first side formed on the side surface of the substrate main body in the region where heat generated by the light emitting element is conducted so as to be fixed from the main surface side to the opposite surface side when soldered to the motherboard. A first heat dissipation layer made of a heat dissipation material; and a main surface of the substrate body including at least a mounting portion of the light emitting element, electrically insulated from a part of the wiring conductor, and the first heat dissipation. And a second heat dissipation layer made of a second heat dissipation material formed so as to be connected to the layer.

  In the light emitting element substrate of the present invention, it is preferable that the first heat radiation layer is formed at a position at the shortest distance from the light emitting element mounting portion on the side surface of the substrate main body. In the light emitting element substrate of the present invention, the substrate body has a notch portion at a side surface position where the first heat dissipation layer is formed, and the first heat dissipation layer is formed on a surface of the notch portion. Preferably it is.

  In the substrate for light emitting device of the present invention, the inorganic insulating material constituting the substrate body is preferably a sintered body of a glass ceramic composition containing glass powder and a ceramic filler. The substrate body preferably does not have a thermal via. In the light emitting element substrate of the present invention, it is preferable that the first heat dissipation material and the second heat dissipation material are metal materials containing silver.

  The light-emitting device of the present invention includes a light-emitting element substrate of the present invention, a light-emitting element mounted on the light-emitting element substrate, a motherboard having a heat sink and a wiring circuit on which the light-emitting element substrate is mounted, and the light-emitting device. A solder layer for fixing an element substrate to the mother board, the solder layer being formed to connect the first heat dissipation layer and the heat sink.

  According to the light emitting element substrate of the present invention, it is economically advantageous compared to thermal vias and can ensure flatness, and when the light emitting device is formed, the light emitting element sufficiently generates heat together with the other structures of the light emitting device. Can be dissipated. Further, by using the substrate for a light emitting element of the present invention, sufficient heat dissipation can be obtained without using a thermal via that deteriorates the flatness of the substrate surface, so that the light emitting element and the substrate can be easily bonded. There are also advantages. Further, according to the present invention, by mounting the light emitting element on such a light emitting element substrate and mounting the light emitting element on the mother board, the heat generated by the light emitting element is sufficiently dissipated and the light emitting device has sufficient light emission luminance. Is obtained.

It is a top view which shows an example of 1st Embodiment of the board | substrate for light emitting elements of this invention using a LTCC board | substrate, XX sectional drawing of this top view, and YY sectional drawing of this top view. It is a top view which shows an example of the light-emitting device of this invention using the board | substrate for light emitting elements shown in FIG. 1, XX sectional drawing of this top view, and YY sectional drawing of this top view. It is the top view which shows an example of 2nd Embodiment of the board | substrate for light emitting elements of this invention using a LTCC board | substrate, XX sectional drawing of this top view, and YY sectional drawing of this top view. It is a top view which shows an example of the light-emitting device of this invention using the board | substrate for light emitting elements shown in FIG. 2, XX sectional drawing of this top view, and YY sectional drawing of this top view. It is a top view which shows another example of 2nd Embodiment of the light emitting element substrate of this invention using a LTCC board | substrate, XX sectional drawing of this top view, and YY sectional drawing of this top view . It is the top view which shows the board | substrate for light emitting elements of this invention using the LTCC board | substrate produced in Example 3, XX sectional drawing of this top view, and YY sectional drawing of this top view.

Embodiments of the present invention will be described below with reference to the drawings. In addition, this invention is limited to the following description and is not interpreted.
A substrate for a light emitting device of the present invention is a substrate body made of an inorganic insulating material having a part of a wiring conductor for electrically connecting an electrode of the light emitting device to a wiring circuit of a motherboard on a main surface on which the light emitting device is mounted. And a first side formed on the side surface of the substrate main body in the region where heat generated by the light emitting element is conducted so as to be fixed from the main surface side to the opposite surface side when soldered to the motherboard. A first heat dissipation layer made of a heat dissipation material; and a main surface of the substrate body including at least a mounting portion of the light emitting element, electrically insulated from a part of the wiring conductor, and the first heat dissipation. And a second heat dissipation layer made of a second heat dissipation material formed so as to be connected to the layer.

  Here, in the present specification, the “wiring conductor” of the light emitting element substrate is provided so as to be electrically connected to the wiring circuit of the mother board from the electrode of the light emitting element to be mounted. Connected to all conductors related to the electrical wiring, for example, element connection terminals connected to the electrodes of the light emitting elements, inner layer wiring provided in the board (including through conductors penetrating through the board), and wiring circuit of the motherboard The term “external connection terminal” is used as a generic term.

According to the present invention, the side surface of the substrate body made of an inorganic insulating material in the region where the heat generated by the light emitting element is conducted extends from the surface (main surface) side on which the light emitting element is mounted to the opposite surface side. A first heat dissipation layer is formed, and further includes at least a light emitting element mounting portion on the main surface, and is electrically insulated from a part of the wiring conductor and connected to the first heat dissipation layer. By forming the layer, the heat generated by the light emitting element is guided from the main surface to the first heat dissipation layer on the side surface via the second heat dissipation layer, and further to the external heat sink via the first heat dissipation layer. It was.
Here, according to the present invention, the external heat sink is not specially provided, but by using the first heat dissipation layer formed on the side surface as a fixing portion when the substrate body is soldered to the motherboard by a normal method. The solder layer is used as a heat dissipation means, which is economically advantageous. Further, according to this configuration, a large amount of heat can be finally led from the solder layer to the heat sink of the mother board.

  The substrate body constituting the light emitting element substrate of the present invention has a notch portion at a side surface position where the first heat dissipation layer is formed, and the first heat dissipation layer is formed on the surface of the notch portion. With this configuration, it is easy to connect the second heat dissipation layer and the first heat dissipation layer formed on the main surface of the substrate body, and the solder layer for soldering to the motherboard has a large capacity. This is advantageous and preferable in that the solder layer can be easily formed.

  According to the present invention, the above configuration enables sufficient dissipation of the heat generated from the light emitting element without providing a thermal via that requires an increased number of manufacturing steps and a large amount of silver or the like to be filled therein. It is what.

  The constituent material of the substrate body used in the present invention is made of an inorganic insulating material. Specifically, as such an inorganic insulating material, specifically, sintering of a glass ceramic composition containing alumina, aluminum nitride, glass powder and a ceramic filler. Examples include LTCC consisting of a body. In the present invention, when the substrate body is made of alumina or LTCC, the structural advantage for obtaining a large heat dissipation is great, and further, when the substrate body is made of LTCC, a great advantage can be obtained.

Hereinafter, the embodiment of the substrate for a light emitting element of the present invention will be described by taking the case where LTCC is used as the constituent material of the substrate body as an example.
As described above, the light-emitting element substrate of the present invention includes the substrate body, the first heat dissipation layer, and the second heat dissipation layer having the above-described configurations of the present invention as essential components. Since both the first heat dissipation layer and the second heat dissipation layer are usually made of a metal material excellent in heat dissipation, the second heat dissipation layer is separate from the first heat dissipation layer in which a solder layer is further formed on the surface thereof. It is preferable that the layer further has a structure for insulating and protecting the layer. Therefore, the substrate for a light emitting device of the present invention usually has an insulating protective layer formed on the main surface of the substrate main body so as to cover the whole including the edge of the second heat dissipation layer. Further, the substrate body constituting the light emitting element substrate preferably has a reflective layer that reflects light reaching the main surface from the light emitting element to the light extraction side on the main surface having the light emitting element mounting portion. In the present invention, it is possible to allow these to function as a reflective layer by adjusting these materials and shapes in the combination of the second heat dissipation layer and the insulating protective layer without providing a separate reflective layer. .

  For example, a substrate body having a part of a wiring conductor for electrically connecting an electrode of a light emitting element to a wiring circuit of a motherboard on the main surface, a part of the wiring conductor on the main surface and the vicinity thereof A second heat radiating layer made of a heat radiating and reflecting material, for example, a metal material containing silver, is formed in a shape excluding the peripheral portion of the main surface so as to cover the whole including the edge of the heat radiating layer. By forming an insulating protective layer made of glass, the second heat dissipation layer can also be used as a reflective layer. In this configuration, if the insulating protective layer is formed of a reflective LTCC material instead of glass, the insulating protective layer can also be used as a reflective layer.

  Here, from the viewpoint of heat dissipation, as the heat dissipation route, heat is conducted from the light emitting element mounting portion to the second heat dissipation layer and the first heat dissipation layer, and further through the solder layer to the heat sink of the motherboard. It is an essential requirement to be formed in this way. In consideration of obtaining higher heat dissipation, it is preferable to provide the second heat dissipation layer so that heat can be efficiently transferred to the first heat dissipation layer.

  Depending on the design of the light emitting device, the insulating protective layer may not be provided on the second heat dissipation layer in the light emitting element substrate. The configuration related to heat dissipation in the light emitting element substrate of the present invention is also applicable to a light emitting element substrate having a design that does not have an insulating protective layer on the second heat dissipation layer.

  In the case of using a glass layer (hereinafter also referred to as an overcoat glass layer) as the insulating protective layer in the embodiment of the light emitting element substrate of the present invention, using LTCC as a constituent material of the substrate body as an example. In the following, the first embodiment and the case where a reflective LTCC layer is used as the insulating protective layer will be described as a second embodiment. Note that each of the examples of the light-emitting element substrates of the first embodiment and the second embodiment described below has a notch portion on the side surface of the preferred substrate body in the present invention, and the first heat dissipation layer on the surface thereof. Is an example in which is formed.

<First Embodiment>
FIG. 1 is a plan view (a) showing an example of a light emitting element substrate 1 according to the first embodiment of the present invention using an LTCC substrate, a cross-sectional view taken along line XX in the plan view (a), and It is YY sectional view (c) in a top view (a).

The light emitting element substrate 1 has a substantially flat substrate body 2 that mainly constitutes the substrate. The substrate body 2 is made of a sintered body of a glass ceramic composition containing glass powder and a ceramic filler. The substrate body 2 has a surface on which the light emitting element is mounted as a main surface 21 as a light emitting element substrate, and in this example, the opposite surface is a back surface 23. In this example, the main surface 21 and the back surface 23 are substantially rectangular.
In this specification, “substantially flat” means that the general shape is flat on the visual level, and “substantially rectangular” means that the approximate shape is rectangular on the visual level. In the present specification, the term “substantially” is used as a term for expressing an approximate shape or the like on a visual level.

  The substrate 1 for light emitting elements has a frame 8 on the peripheral portion of the main surface 21 so as to form a cavity having a substantially rectangular portion at the center of the main surface 21 as a bottom surface (hereinafter referred to as “cavity bottom surface”). Although the material which comprises the frame 8 is not specifically limited, It is preferable to use the same material as the substrate body 2. In addition, the light emitting element mounting portion 22 is positioned substantially at the center of the cavity bottom surface. In this example, the light emitting element to be mounted has a substantially rectangular parallelepiped shape, and is mounted so that the long side of the substrate body 2 and the long side of the light emitting element are parallel to each other.

  The substrate main body 2 has a cutout portion 24 in which the cutout portion from the main surface 21 side to the backside 23 side has a semi-cylindrical shape at the substantially central portion of each of the two long side surfaces. In this example, the notch 24 is formed on the side surface on the long side, which is a preferred position in the present invention, at a position closest to the light emitting element to be mounted. However, the notch 24 is formed at this position by design. When it is difficult, it is preferable to form it on the side surface as close to the light emitting element as possible in the region where heat generated by the mounted light emitting element is conducted.

  Further, although the number of the notches 24 is two in this example, the number can be adjusted as necessary within a range not impairing the effects of the present invention. The shape of the notch 24 is not particularly limited. However, since the notch 24 serves as a fixing part when the substrate body 2 is fixed to the mother board by soldering, it is preferable that the notch 24 be easily fixed by solder. Further, the notch 24 is usually provided continuously from the side surface of the substrate body 2 so as to extend from the substrate body side to the upper surface of the side surface of the frame body 8 provided on the peripheral portion of the main surface 21 of the substrate body 2. ing. The notch 24 is preferably formed in a size that does not reach the inner wall of the frame 8.

  A first heat radiation layer 9 made of a first heat radiation material is formed on the entire surface of the notch 24. Note that, depending on the design of the light emitting element substrate and the light emitting device in which the light emitting element substrate is used, the first heat dissipation layer 9 may be formed only on the surface of the notch portion of the substrate body 2 in the surface of the notch portion 24. At least the first heat dissipation layer 9 and the second heat dissipation layer 3 described below are connected to the surface of the notch 24 in the first heat dissipation layer 9, and an area required for fixing the solder is secured. The base body 2 may be formed so as to reach a desired height from the back surface 23 side.

  The first heat dissipating material constituting the first heat dissipating layer 9 is not particularly limited as long as it is a heat dissipating material, and further considering the ease of sucking up solder, etc., a metal material containing silver, Specifically, a metal material composed of silver, silver and platinum, or silver and palladium is preferably used.

  The thickness of the first heat dissipation layer 9 is not particularly limited as long as the heat conducted from the second heat dissipation layer 3 described below can guide the heat to the heat sink of the motherboard via solder. Specifically, a film thickness of 5 to 50 μm is preferable, and a film thickness of 20 to 40 μm is more preferable. If the film thickness of the first heat dissipation layer 9 is less than 5 μm, pinhole defects may occur, and if it exceeds 50 μm, it is economically disadvantageous and deformation due to a difference in thermal expansion from the substrate body may occur during the manufacturing process. Concerned. Moreover, the 1st thermal radiation layer 9 may be comprised with the laminated body of a different metal layer as needed.

  The substrate body 2 preferably has a bending strength of, for example, 250 MPa or more from the viewpoint of suppressing damage or the like when the light emitting element is mounted and thereafter used. The shape, thickness, size and the like of the substrate body 2 and the frame body 8 other than the side cutout 24 are not particularly limited, and can be the same as those usually used as a light emitting element substrate. The raw material composition, sintering conditions, etc. of the sintered body of the glass-ceramic composition containing the glass powder and the ceramic filler constituting the substrate body 2 will be described in a method for manufacturing a light-emitting element substrate described later.

  The light emitting element substrate 1 has a substantially rectangular parallelepiped shape on the main surface 21 and a pair of electrodes included in the light emitting element mounted so that the long side of the substrate body 2 and the long side of the light emitting element are parallel to each other, respectively. A pair of electrically connected element connection terminals 5 are provided so as to face both outer sides of the short side of the mounting portion with the light emitting element mounting portion 22 in between.

  The back surface 23 is provided with a pair of external connection terminals 6 that are electrically connected to a wiring circuit of the motherboard, on which the substrate body 2 is mounted via the back surface 23 when the light emitting device is formed. Are provided with a pair of through conductors 7 for electrically connecting the element connection terminal 5 and the external connection terminal 6. The element connection terminal 5, the external connection terminal 6 and the through conductor 7 are arranged as long as they are electrically connected to the light emitting element → the element connection terminal 5 → the through conductor 7 → the external connection terminal 6 → the wiring circuit. The positions and shapes to be used are not limited to those shown in FIG. 1 and can be adjusted as appropriate.

  The component connection terminals 5, the external connection terminals 6, and the through conductors 7, that is, the constituent materials of the wiring conductors can be used without particular limitation as long as they are the same constituent materials as the wiring conductors usually used for the light emitting element substrate. Specific examples of the constituent material of these wiring conductors include metal materials mainly composed of copper, silver, gold and the like. Among such metal materials, a metal material composed of silver, silver and platinum, or silver and palladium is preferably used.

  In addition, in the element connection terminal 5 and the external connection terminal 6, and also in the first heat dissipation layer 9, the element connection terminal 5 and the external connection terminal 6 made of these metal materials are preferably 5 to 15 μm thick. The heat dissipation layer 9 preferably has a thickness of 5 to 50 μm, and has a structure in which a conductive protective layer having a conductivity and protecting these layers from oxidation and sulfuration is formed on a metal conductor layer. . The conductive protective layer is not particularly limited as long as it is made of a conductive material having a function of protecting the metal conductor layer. For the element connection terminal 5, a gold plating layer is preferable, and gold plating is applied on nickel plating. The structure of the applied nickel / gold plating layer is more preferable. Further, a nickel plating layer is preferable for the external connection terminal 6 and the first heat dissipation layer 9. The thickness of the conductive protective layer is preferably 3 to 20 μm for the nickel plating layer and 0.1 to 1.0 μm for the gold plating layer.

  The main surface 21 of the light emitting element substrate 1 is connected to the first heat-dissipating layer 9 except for its peripheral edge, the portion where the pair of element connection terminals 5 are disposed, and the vicinity thereof. The second heat radiation layer 3 made of the second heat radiation material is formed. In this example, the second heat radiating layer 3 is provided so as to have a width of about 略 of the distance between the pair of element connection terminals 5 in the center in the long side direction of the main surface 21. The short side direction is also provided between the substrate body 2 and the frame body 8 with an appropriate distance inside from the edge of the substrate body main surface 2. The distance of the edge of the second heat radiation layer 3 from the edge of the main surface 2 of the substrate body is preferably at least 50 μm, and more preferably 75 μm or more. However, at the position where the notch 24 is provided on the side surface, the edge of the second heat radiation layer 3 reaches the edge of the main surface 2 of the substrate main body, thereby connecting to the first heat radiation layer 9. Yes.

  From the viewpoint of heat dissipation, as a heat dissipation route, heat is transmitted from the light emitting element mounting portion 22 to the second heat dissipation layer 3 and the first heat dissipation layer 9, and further through the solder layer to the heat sink of the motherboard. It is essential to be formed so as to conduct. In view of obtaining higher heat dissipation properties, it is preferable that the second heat dissipation layer 3 is appropriately adjusted in area, shape, etc. so that heat can be efficiently transferred to the first heat dissipation layer 9.

  The second heat dissipating material constituting the second heat dissipating layer 3 can be the same material as the first heat dissipating material or a different material. The second heat radiating material is preferably a material having a reflective property in addition to the heat radiating property. As such a heat dissipation material, a metal material containing silver, specifically, a metal material composed of silver, silver and platinum, or silver and palladium, can be used as in the first heat dissipation material. Among these, a heat dissipation layer composed only of silver is preferable in the present invention because a high reflectance can be obtained. Moreover, the 2nd thermal radiation layer 3 may be comprised with the laminated body of a different metal layer as needed.

  The film thickness of the second heat dissipation layer 3 can be adjusted as appropriate depending on the configuration of the light-emitting device to be used, but is preferably 8 to 50 μm, and more preferably 20 to 40 μm. If the film thickness of the second heat dissipation layer 3 is less than 8 μm, heat may not be sufficiently conducted toward the first heat dissipation layer 9. Further, if it exceeds 50 μm, it is economically disadvantageous and there is a concern that deformation due to a difference in thermal expansion from the substrate body occurs in the manufacturing process.

  The second heat dissipation layer 3 preferably has a flat surface. Specifically, the surface flatness should be 0.15 μm or less as the surface roughness Ra at least in the light emitting element mounting portion 22 from the viewpoint of manufacturing ease while ensuring sufficient heat dissipation. Is preferable, and it is more preferable that it is 0.1 micrometer or less. The surface roughness Ra is the arithmetic average roughness Ra, and the value of the arithmetic average roughness Ra is represented by 3 “Definition and display of defined arithmetic average roughness” of JIS: B0601 (1994). It is what is done.

  On the main surface 21 of the substrate body 2, an overcoat glass layer 4 is formed as an insulating protective layer having a flat surface so as to cover the entire surface including the edge of the second heat dissipation layer 3. Here, as long as the insulation between the element connection terminal 5 provided on the main surface 21 and the second heat radiation layer 3 is ensured, the edge of the overcoat glass layer 4 is in contact with the element connection terminal 5. However, in consideration of the occurrence of defects in production, the distance between the two is preferably 75 μm or more, and more preferably 100 μm or more.

  Further, the distance between the edge of the second heat radiation layer 3 and the edge of the overcoat glass layer 4 covering the second heat radiation layer 3 can be within a range in which the second heat radiation layer 3 is sufficiently protected from external deterioration factors. It is preferable that the distance is as short as possible. Specifically, it is preferably 10 to 50 μm, and more preferably 20 to 30 μm. If this distance is less than 10 μm, the exposure of the second heat dissipation layer 3 may cause oxidation or sulfidation of the metal material including silver constituting the second heat dissipation layer 3, which may reduce thermal conductivity and heat dissipation. If it exceeds 50 μm, as a result, the area of the region where the second heat radiation layer 3 is disposed may be reduced, so that the thermal conductivity and heat dissipation may be lowered.

  When the insulating protective layer is the overcoat glass layer 4 as in this example, the film thickness of the overcoat glass layer 4 depends on the design of the light emitting device, but ensures a sufficient insulation protection function and is economical. In consideration of the property, deformation due to a difference in thermal expansion from the substrate body, etc., it is preferably 5 to 50 μm.

  The overcoat glass layer 4 preferably has a flat surface. Specifically, the surface flatness is 0.03 μm or less as the surface roughness Ra at least in the light emitting element mounting portion 22 from the viewpoint of manufacturing ease while ensuring sufficient heat dissipation. Is preferable, and it is more preferable that it is 0.01 micrometer or less. In addition, the raw material composition regarding an overcoat glass layer is demonstrated in the below-mentioned manufacturing method.

  Here, in order to obtain sufficient heat dissipation in the light emitting element substrate, a thermal via is usually disposed immediately below the light emitting element mounting portion. At that time, a special method is used to suppress the unevenness of the mounting portion caused by the arrangement of the thermal via. However, even if such a method is used, the height of the highest and lowest portions of the unevenness is reduced. At present, the difference is limited to about 1 μm or less.

In the present invention, sufficient heat dissipation is ensured without the provision of thermal vias that cause unevenness in the light emitting element mounting portion according to the above configuration. The difference in height from the lowest portion is equivalent to the surface other than the mounting portion, that is, the surface of the insulating protective layer in the present invention, and is generally 0.5 μm or less.
In other words, in the configuration of the present invention, the flatness of the mounting portion can be easily flattened more easily than when the thermal via is provided, compared to the case where the thermal via is provided while having sufficient heat dissipation. Is. When the flatness is good, the adhesion between the light emitting element and the shipping element mounting portion is improved, the thermal resistance at the interface is reduced, and the heat dissipation is improved.

The light emitting element substrate 1 according to the first embodiment of the present invention has been described above. Next, an example of the light emitting device 10 of the present invention using the light emitting element substrate 1 will be described with reference to FIG.
2 is a plan view (a) showing an example of the light emitting device 10 of the present invention using the light emitting element substrate 1 shown in FIG. 1, a sectional view taken along line XX in the plan view (a), and a plan view. It is YY sectional view (c) in figure (a).

  When the light emitting device 10 in this example is manufactured using the substrate 1 for light emitting elements, a light emitting element 11 such as a light emitting diode element having a substantially rectangular parallelepiped shape as shown in FIG. Fixed and mounted on the light emitting element mounting portion 22 at the substantially central portion of the bottom surface of the cavity with a die bond agent such as a silicone die bond agent or a metal bond agent so that the long side of the substrate body 2 and the long side of the light emitting element 11 are parallel to each other. Is done. In the light emitting device 10, a pair of electrodes (not shown) included in the light emitting element 11 are electrically connected to the element connection terminals 5 located on the outside thereof via bonding wires 12. Further, a sealing layer 13 is provided so as to fill the cavity so as to cover the light emitting element 11 and the bonding wire 12.

  The light emitting device 10 includes a mother board 31 such as a printed wiring board. On the mother board 31, the substrate body 2 on which the light emitting element 11 is mounted covers a part of the surface of the heat sink 33 formed on the main surface of the mother board. The solder layer 32 is formed and filled in such a manner that the notch 24 is filled with solder.

  The mother board 31 has, for example, an insulating resin layer 35 on the main surface on which the substrate body 2 on which the light emitting element 11 is mounted is made of a metal material, and the wiring circuit 34 and the insulating resin layer 35. The heat sinks 33 are arranged independently without being in contact with each other. The solder layer 32 is formed on the heat sink 33 as described above.

As the solder material constituting the solder layer 32, a solder material used for fixing a substrate made of an inorganic insulating material to a mother board is usually usable without any particular limitation. Specifically, a solder material composed of tin and silver, tin and copper, or the like can be given. Usually, the height of the solder layer 32 in the vertical direction is highest at the portion in contact with the first heat dissipation layer 9. Although the height depends on the size and shape of the light emitting device, it is preferably about 0.5 to 1 mm from the viewpoint of sufficiently ensuring heat dissipation and fixing properties, and the solder layer 32 is preferably the first heat dissipation layer 9. The area in contact with is preferably approximately 0.25 to 0.5 mm ² . The area of the portion where the solder layer 32 is in contact with the heat sink 33 on the mother board 31 is preferably approximately 0.04 to 0.07 mm ² from the viewpoint of ensuring sufficient heat dissipation and fixing properties.

  The material constituting the heat sink 33 is not particularly limited as long as the material can fix the solder layer 32 and dissipate heat. Specifically, a metal material usually used as a material for a heat sink formed on the mother board, for example, aluminum, copper, or the like can be used without particular limitation. In addition, the size of the heat sink 33, that is, the thickness, area, and shape of the heat sink 33 takes into consideration the type of metal material constituting the heat sink, the output of the light emitting element to be mounted, the structure of the light emitting element substrate, the size and shape of the solder layer, and the like. And it adjusts suitably.

  In the light emitting device 10, with the above configuration, the heat generated by the light emitting element is easily dissipated by conducting smoothly in the order of the second heat dissipation layer 3 → the first heat dissipation layer 9 → the solder layer 32 → the heat sink 33. Is done.

  Further, the light emitting element substrate 1 is arranged on the main surface of the mother board 31 so that the external connection terminals 6 formed on the back surface 23 are electrically connected to a part of the wiring circuit 34 formed on the main surface of the mother board 31. The solder is fixed on the formed heat sink 33.

  Here, the light emitting element substrate of the first embodiment of the present invention can be manufactured by, for example, a manufacturing method described below. In addition, about the member used for manufacture, the same code | symbol as the member of a finished product is attached | subjected and demonstrated.

(1) Production of Green Sheet and Formation of Notch and Through Hole First, the side on which the light emitting element is mounted, which constitutes the substrate body 2 of the light emitting element substrate using a glass ceramic composition containing glass powder and a ceramic filler. A substantially flat substrate body green sheet 2 and a frame green sheet 8 constituting the frame 8 are prepared.
The substrate green sheet 2 and the frame green sheet 8 are prepared by adding a binder and, if necessary, a plasticizer, a dispersant, a solvent, etc. to a glass ceramic composition containing glass powder and a ceramic filler. It can be manufactured by forming this into a sheet of a predetermined shape by the doctor blade method or the like and drying it.

  The glass powder for substrate body and frame (hereinafter referred to as “glass powder for substrate body”) is not necessarily limited, but preferably has a glass transition point (Tg) of 550 ° C. or more and 700 ° C. or less. When the glass transition point (Tg) is less than 550 ° C., degreasing may be difficult. When the glass transition point (Tg) exceeds 700 ° C., the shrinkage start temperature becomes high and the dimensional accuracy may be lowered.

As such a glass powder for a substrate body, for example, SiO ₂ is 57 mol% to 65 mol%, B ₂ O ₃ is 13 mol% to 18 mol%, CaO is 9 mol% to 23 mol%, and Al ₂ O ₃ is 3 mol%. It is preferably 8 mol% or less and containing at least one selected from K ₂ O and Na ₂ O in total from 0.5 mol% to 6 mol%. By using such a thing, it becomes easy to improve the flatness of the substrate main body surface.

Here, SiO ₂ becomes a glass network former. When the content of SiO ₂ is less than 57 mol%, it is difficult to obtain a stable glass and the chemical durability may be lowered. On the other hand, when the content of SiO ₂ exceeds 65 mol%, the glass melting temperature and the glass transition point (Tg) may be excessively high. The content of SiO ₂ is preferably 58 mol% or more, more preferably 59 mol% or more, and particularly preferably 60 mol% or more. The content of SiO ₂ is preferably 64 mol% or less, more preferably 63 mol% or less.

B ₂ O ₃ is a glass network former. If the content of B ₂ O ₃ is less than 13 mol%, there is a possibility that the glass melting temperature or the glass transition point (Tg) becomes too high. On the other hand, when the content of B ₂ O ₃ exceeds 18 mol%, it is difficult to obtain a stable glass and the chemical durability may be lowered. The content of B ₂ O ₃ is preferably 14 mol% or more, more preferably 15 mol% or more. Further, the content of B ₂ O ₃ is preferably 17 mol% or less, more preferably 16 mol% or less.

Al ₂ O ₃ is added to increase the stability, chemical durability, and strength of the glass. When the content of Al ₂ O ₃ is less than 3 mol%, the glass may become unstable. On the other hand, when the content of Al ₂ O ₃ exceeds 8 mol%, the glass melting temperature and the glass transition point (Tg) may be excessively high. The content of Al ₂ O ₃ is preferably 4 mol% or more, more preferably 5 mol% or more. The content of Al ₂ O ₃ is preferably 7 mol% or less, more preferably 6 mol% or less.

  CaO is added to increase glass stability and crystal precipitation, and to lower the glass melting temperature and the glass transition point (Tg). When the content of CaO is less than 9 mol%, the glass melting temperature may be excessively high. On the other hand, when the content of CaO exceeds 23 mol%, the glass may become unstable. The content of CaO is preferably 12 mol% or more, more preferably 13 mol% or more, and particularly preferably 14 mol% or more. The CaO content is preferably 22 mol% or less, more preferably 21 mol% or less, and particularly preferably 20 mol% or less.

K ₂ O and Na ₂ O are added to lower the glass transition point (Tg). When the total content of K ₂ O and Na ₂ O is less than 0.5 mol%, the glass melting temperature and the glass transition point (Tg) may be excessively high. On the other hand, when the total content of K ₂ O and Na ₂ O exceeds 6 mol%, chemical durability, particularly acid resistance may be lowered, and electrical insulation may be lowered. The total content of K ₂ O and Na ₂ O is preferably 0.8 mol% or more and 5 mol% or less.

  In addition, the glass powder for substrate bodies is not necessarily limited to what consists only of the said component, Other components can be contained in the range with which various characteristics, such as a glass transition point (Tg), are satisfy | filled. When other components are contained, the total content is preferably 10 mol% or less.

  The glass powder for a substrate body can be obtained by producing glass having the above glass composition by a melting method and pulverizing it by a dry pulverization method or a wet pulverization method. In the case of the wet pulverization method, it is preferable to use water as a solvent. For the pulverization, for example, a pulverizer such as a roll mill, a ball mill, or a jet mill is used.

The 50% particle size (D ₅₀ ) of the glass powder for substrate main body is preferably 0.5 μm or more and 2 μm or less. When the 50% particle size of the glass powder for substrate main body is less than 0.5 μm, the glass powder is likely to aggregate, making it difficult to handle and uniformly dispersing. On the other hand, when the 50% particle size of the glass powder for substrate main body exceeds 2 μm, the glass softening temperature may increase or the sintering may be insufficient. The particle size can be adjusted, for example, by classification as necessary after pulverization. In the present specification, the particle diameter means a value obtained by a particle diameter measuring apparatus using a laser diffraction / scattering method.

On the other hand, as the ceramic filler, those conventionally used for the production of LTCC substrates can be used without particular limitation. For example, alumina powder, zirconia powder, or a mixture of alumina powder and zirconia powder can be suitably used. The 50% particle size (D ₅₀ ) of the ceramic filler is preferably, for example, from 0.5 μm to 4 μm.

  Mixing and mixing such glass powder for substrate main body and ceramic filler such that glass powder for substrate main body is 30 mass% to 50 mass% and ceramic filler is 50 mass% to 70 mass%, for example. Thus, a glass ceramic composition can be obtained. Moreover, a slurry can be obtained by adding a binder and, if necessary, a plasticizer, a dispersant, a solvent and the like to the glass ceramic composition.

As the binder, for example, polyvinyl butyral, acrylic resin and the like can be suitably used. As the plasticizer, for example, dibutyl phthalate, dioctyl phthalate, butyl benzyl phthalate and the like can be used. Moreover, as a solvent, organic solvents, such as toluene, xylene, 2-propanol, 2-butanol, can be used conveniently.
The slurry thus obtained is formed into a sheet having a predetermined shape by a doctor blade method or the like, and dried to produce the substrate main body green sheet 2 and the frame body green sheet 8.

Next, with respect to each of the substrate main body green sheet 2 and the frame body green sheet 8 obtained as described above, a normal center portion of two long side surfaces is arranged so as to reach the back surface from the upper surface side of each green sheet. The substrate body portion and the frame portion cutout portions 24 are formed by cutting out by the method. In this example, the notch portion 24 is formed so that the notch shape is a semi-cylindrical shape. Further, depending on the thickness of the substrate main body green sheet 2 and the frame body green sheet 8, the notch 24 may be formed after the lamination.
Further, through holes for forming through conductors 7 penetrating from the main surface 21 to the back surface 23 are formed in a predetermined size and shape at two predetermined positions on the substrate main body green sheet 2 by a normal method.

(2) Formation of wiring conductor paste layer / heat dissipating layer metal paste layer Next, the through conductor paste layer 7 is inserted into two through holes of the substrate main body green sheet 2 obtained in the above (1). In order to connect to the conductor paste layer 7, the element connection terminal paste layer 5 at two locations on the main surface 21 and the external connection terminal conductor paste layer 6 at two locations on the back surface 23, each of a predetermined size, Form in shape.
In these elements, the electrodes of the light emitting elements to be mounted are electrically connected to the wiring circuit of the motherboard via the element connection terminal paste layer 5, the through conductor paste layer 7, and the external connection terminal conductor paste layer 6. Formed as follows.

  Examples of the method for forming the element connection terminal paste layer 5, the external connection terminal conductor paste layer 6, and the through conductor paste layer 7 include a method of applying and filling the conductor paste by a screen printing method. The film thicknesses of the element connection terminal paste layer 5 and the external connection terminal conductor paste layer 6 to be formed are adjusted so that the film thicknesses of the element connection terminals and the external connection terminals that are finally obtained have a predetermined film thickness. .

  As the wiring conductor paste, for example, a paste obtained by adding a vehicle such as ethyl cellulose to a metal powder mainly composed of copper, silver, gold or the like, and a solvent or the like as required can be used. As the metal powder, a metal powder made of silver and a metal powder made of silver and platinum or palladium are preferably used.

  Further, for each of the substrate main body green sheet 2 and the frame body green sheet 8 obtained in the above (1), the first heat dissipating layer metal paste layer 9 is screened on each of the surfaces of the two notches 24. It is formed by printing. Depending on the design of the light emitting element substrate / light emitting device, the first heat dissipation layer metal paste layer 9 is screen-printed only on the surfaces of the two base body part cutout portions of the substrate body green sheet 2, The frame body green sheet 8 may not be formed in the frame part cutout portion. The 1st metal paste for heat dissipation layers used for screen printing is a paste containing the heat dissipation material which comprises the 1st heat dissipation layer 9, Preferably, the metal material containing silver. As such a material, silver, a silver palladium mixture, a silver platinum mixture, etc. are mentioned as above-mentioned.

  As the first metal paste for the heat radiation layer, a paste obtained by adding a vehicle such as ethyl cellulose to a metal powder containing such a material as a main component and, if necessary, a solvent or the like can be used. The film thickness of the first heat radiation layer metal paste layer 9 to be formed is adjusted so that the film thickness of the first heat radiation layer 9 finally obtained becomes the desired film thickness.

Next, the element connection terminal paste layer 5 on the main surface 21 of the substrate body green sheet 2 having the wiring conductor paste layer and the base body part notch portion and the first heat dissipating layer metal paste layer 9 formed on the surface thereof, A second heat dissipating layer metal paste layer 3 containing a heat dissipating material is formed by screen printing in the vicinity of the periphery and the region excluding the peripheral portion of the main surface. More specifically, the second heat dissipating layer metal paste layer 3 has an end in a direction corresponding to the short side direction of the substrate body green sheet 2 at a substantially central portion on the main surface 21 of the substrate body green sheet 2. The edge reaches the notch 24 (base body portion) formed on the side surface and is connected to the first heat dissipation layer 9, and the edge in the direction corresponding to the long side direction of the substrate body green sheet 2 is Each of the pair of element connection terminals 5 is provided so as to be located at an inner position by about 1/3 of the distance between them.
The second heat radiation layer metal paste layer is formed simultaneously with the element connection terminal paste layer 5 when the conductor paste and the second heat radiation layer metal paste are made of the same paste material, for example. Can be formed.

The second metal paste for heat dissipation layer used for the screen printing is a paste containing a heat dissipation material constituting the second heat dissipation layer 3, preferably a metal material containing silver. Examples of such a material include silver, a silver palladium mixture, a silver platinum mixture and the like as described above, and silver is preferably used for the above reasons. As the second metal paste for the heat radiation layer, a paste obtained by adding a vehicle such as ethyl cellulose, a solvent or the like, if necessary, to a metal powder mainly composed of such a material can be used. The film thickness of the formed second heat radiating layer metal paste layer 3 is adjusted so that the film thickness of the finally obtained second heat radiating layer 3 becomes the desired film thickness.
Moreover, in order to make the surface roughness Ra of the 2nd heat dissipation layer 3 finally obtained into the said preferable range, it is preferable to use a powder with little particle size distribution as a metal powder contained in a metal paste.

(3) Formation of overcoat glass paste layer Next, on the main surface 21 of the green sheet 2 for substrate main body, covering the whole including the edge of the second metal paste layer 3 for heat dissipation layer formed in (2) above The overcoat glass paste layer 4 is formed by screen printing on the main surface 21 of the substrate body green sheet 2 excluding the element connection terminal paste layer 5 and the vicinity thereof and the peripheral edge of the main surface.

  As the overcoat glass paste, a paste obtained by adding a vehicle such as ethyl cellulose to a glass powder (glass powder for glass film), a solvent or the like as required, can be used. The film thickness of the overcoat glass paste layer 4 to be formed is adjusted so that the film thickness of the finally obtained overcoat glass layer 4 becomes the desired film thickness.

The glass powder for the overcoat glass layer may be any glass powder that can be obtained by baking finally performed, and its 50% particle size (D ₅₀ ) is 0.5 μm or more and 2 μm or less. Is preferred. Further, the surface roughness Ra of the overcoat glass layer 4 can be adjusted by, for example, the particle size of the glass powder for the overcoat glass layer. That is, as the glass powder for the overcoat glass layer, the surface roughness Ra is adjusted to the above preferable range by using a glass powder that is sufficiently melted at the time of firing and has excellent fluidity in the above 50% particle size (D ₅₀ ) range. Can be adjusted.

(4) Lamination of green sheet The first heat dissipating layer metal paste layer 9 and the wiring conductor paste layer (element connection terminal paste) formed on the surface of the notch 24 of the base body portion obtained in the steps up to (3) above. On the main surface of the green sheet 2 for a substrate body having the layer 5, the external connection terminal conductor paste layer 6, and the through conductor paste layer 7), the second heat radiation layer metal paste layer 3 and the overcoat glass paste layer 4 In addition, the cutout portion 24 of the frame portion obtained in the steps up to the above (2) and the metal paste layer 9 for the first heat dissipation layer are provided on the surface thereof, or the cutout portion 24 is provided with the first heat dissipation. The green sheet 8 for a frame body which does not have the metal paste layer 9 for layers is laminated | stacked. Thus, a green sheet laminate having a shape in which the substrate body 2 has a cavity on the main surface and the bottom surface forms a region for mounting the light emitting element is obtained as the green light emitting element substrate 1.

(5) Firing About the unsintered light emitting device substrate 1 obtained in (4) above, degreasing is performed to remove a binder or the like as necessary, and firing for sintering a glass ceramic composition or the like ( Baking temperature: 800-930 ° C.).

  Degreasing can be performed, for example, by holding at a temperature of 500 ° C. to 600 ° C. for 1 hour to 10 hours. When the degreasing temperature is less than 500 ° C. or the degreasing time is less than 1 hour, the binder or the like may not be sufficiently removed. On the other hand, if the degreasing temperature is about 600 ° C. and the degreasing time is about 10 hours, the binder and the like can be sufficiently removed, and if it exceeds this, productivity and the like may be lowered.

  In addition, the firing can be performed by appropriately adjusting the time in a temperature range of 800 ° C. to 930 ° C. in consideration of obtaining a dense structure of the substrate body 2 and the frame body 8 and productivity. Specifically, it is preferable to hold at a temperature of 850 ° C. or higher and 900 ° C. or lower for 20 minutes or longer and 60 minutes or shorter, particularly preferably at a temperature of 860 ° C. or higher and 880 ° C. or lower. If the firing temperature is less than 800 ° C., the substrate body may not be obtained as a dense structure. On the other hand, if the firing temperature exceeds 930 ° C., the productivity may decrease due to deformation of the substrate body. In addition, when a metal paste containing metal powder containing silver as a main component is used as the conductor paste or the reflective film paste, when the firing temperature exceeds 880 ° C., the predetermined shape is maintained because it is excessively softened. There is a risk that it will not be possible.

  In this way, the unsintered light emitting element substrate 1 is fired to obtain the light emitting element substrate 1. After firing, the element connection terminals 5, the external connection terminals 6, and the first heat radiation layer 9 as a whole are necessary. In general, a conductive protective layer used for protecting a conductor in a substrate for a light-emitting element, such as gold plating, nickel plating, nickel / gold plating, etc., may be disposed so as to cover the substrate.

The method for manufacturing the light emitting element substrate according to the first embodiment has been described above. However, the green sheet 2 for the main body and the green sheet for the frame do not necessarily need to be made of a single green sheet. It may be laminated. Further, the order of forming each part can be changed as appropriate as long as the light emitting element substrate can be manufactured.
(6) Production of Light-Emitting Device The method for producing the light-emitting device 10 shown in FIG. 2, for example, using the light-emitting element substrate 1 of the first embodiment is not particularly limited, and the light-emitting element 11 is used for a light-emitting element. All of the conventional methods, such as a method of mounting on the substrate 1, a method of electrical connection such as wire bonding, a method of forming the sealing layer 13 using a sealing agent, and a method of fixing the light emitting element substrate 1 to the mother board 31 by soldering, are all conventional. A known method is applicable.

<Second Embodiment>
Below, the 2nd Embodiment of this invention at the time of using the LTCC layer which has reflectivity as an insulating protective layer is described.
FIG. 3A is a plan view showing an example of a light emitting element substrate 1 according to the second embodiment of the present invention using an LTCC substrate, a cross-sectional view taken along line XX in FIG. It is YY sectional view (c) in a top view (a).

  The light emitting element substrate 1 has a substantially flat substrate body 2 that mainly constitutes the substrate. The substrate body 2 is made of a sintered body of a glass ceramic composition containing glass powder and a ceramic filler. The substrate body 2 has a surface on which the light emitting element is mounted as a main surface 21 as a light emitting element substrate, and in this example, the opposite surface is a back surface 23. In this example, the main surface 21 and the back surface 23 are substantially rectangular.

  The shape, thickness, size, etc. of the substrate body 2 other than a notch 24 to be described later are not particularly limited, and can be the same as those usually used as a light emitting element substrate. Moreover, about the sintered body of the glass ceramic composition containing the glass powder and ceramic filler which comprise the board | substrate body 2, the thing similar to the sintered body of the glass ceramic composition used in the said 1st Embodiment is used. Is possible.

  The back surface 23 of the substrate body 2 is provided with a pair of external connection terminals 6 that are electrically connected to a wiring circuit included in a motherboard on which the substrate body 2 is mounted via the back surface 23 when the light emitting device is used. A pair of through conductors 7 for electrically connecting an element connection terminal 5 described later and the external connection terminal 6 are provided inside the substrate body 2. The through conductor 7 is provided so as to further penetrate the LTCC layer 4 which is an insulating protective layer formed on the main surface of the substrate body 2 described below.

  On the main surface 21 of the substrate body 2, except for the peripheral portion of the main surface 21, the portion where the pair of through conductors 7 are disposed, and the vicinity of the periphery, the shape is connected to a first heat dissipation layer described later. In addition, a second heat dissipation layer 3 made of the second heat dissipation material is formed. In this example, the second heat radiating layer 3 is provided approximately at the center in the long side direction of the main surface 21 so as to have a width of about 1/3 of the distance between the pair of through conductors 7. The short side direction is provided at an appropriate distance from the edge of the main surface 21 to the inside. The distance from the edge of the main surface 21 of the edge of the second heat radiation layer 3 is preferably at least 50 μm, and more preferably 75 μm or more. However, the edge of the second heat radiation layer 3 reaches the edge of the main surface 2 of the substrate body at the position where the cutout portion is provided on the side surface, thereby connecting to the first heat radiation layer.

  The heat dissipation route is formed such that heat is conducted from the light emitting element mounting portion 22 to the second heat dissipation layer 3 and the first heat dissipation layer 9 and further to the heat sink of the motherboard through the solder layer. This is an essential requirement. In view of obtaining higher heat dissipation properties, it is preferable that the second heat dissipation layer 3 is appropriately adjusted in area, shape, etc. so that heat can be efficiently transferred to the first heat dissipation layer 9.

  An LTCC layer 4 made of LTCC having reflectivity is formed on the main surface 21 so as to cover the entire surface including the edge of the second heat dissipation layer 3.

  Here, the through conductor 7 provided inside the substrate main body 2 further extends from the surface on the main surface 21 side of the LTCC layer 4 (hereinafter referred to as “laminated surface”) to the surface on the opposite side of the LTCC layer 4. It is provided in a form that penetrates. The LTCC layer 4 is formed so as to cover the second heat radiation layer 3 on the entire surface of the main surface 21 excluding the portion where the penetrating conductor 7 is disposed, and the surface opposite to the laminated surface (hereinafter referred to as the laminated surface). The light emitting element is mounted on the “mounting surface”.

The constituent material, film thickness, surface characteristics, and the like of the second heat dissipation layer 3 can be the same as those of the second heat dissipation layer 3 of the first embodiment.
When the second heat dissipation layer 3 is disposed on the main surface 21 of the substrate body 2 in consideration of heat dissipation, the LTCC layer 4 covering the second heat dissipation layer 3 is on the main surface 21. Since it adheres to the main surface 21 in a region where the second heat dissipation layer 3 is not provided, the arrangement area of the second heat dissipation layer 3 is adjusted leaving an adhesion area in a range where the adhesion between the two is maintained. . In addition, the distance between the second heat radiation layer 3 and the through conductor 7 may be an electrically insulated distance, but is 100 μm or more in consideration of the occurrence of problems in manufacturing. Is preferable, and it is more preferable that it is 150 micrometers or more.

  In the second embodiment of the present invention, the LTCC layer 4 is made of a reflective LTCC, that is, a sintered body of a glass ceramic composition containing glass powder and a ceramic filler. The thickness of the LTCC layer 4 depends on the design of the light emitting device, but is 5 to 150 μm in consideration of sufficient insulation protection function and economy, deformation due to a difference in thermal expansion from the substrate body, etc. Is preferable, and it is more preferable that it is 50-125 micrometers.

  The LTCC layer 4 preferably has a flat surface. Specifically, the surface flatness is 0.15 μm or less as the surface roughness Ra at least in the portion where the light emitting element 11 is mounted from the viewpoint of ease of manufacturing while ensuring sufficient heat dissipation. Preferably, it is more preferably 0.10 μm or less.

  The sintered body of the glass-ceramic composition containing the glass powder having reflectivity and the ceramic filler, which is a material constituting the LTCC layer 4, is preferably one that can ensure the surface roughness Ra in addition to having reflectivity. Specifically, in the glass ceramic composition for a substrate body, the ceramic filler is pulverized by increasing the kneading time in the paste preparation step, and the surface roughness Ra can be in the above range.

  The sintered body of the glass ceramic composition having reflectivity constituting the LTCC layer 4 is a sintered body of the glass ceramic composition which is a constituent material of the substrate body 2 in consideration of the adhesion to the substrate body 2. The glass ceramic composition having a composition different from that of the glass ceramic composition may be used in consideration of the reflectivity of reflecting light from the light emitting element in the light extraction direction.

  As the glass ceramic composition having reflectivity, for example, in the above glass ceramic composition for a substrate body, the same glass powder is used, and the ceramic ceramic filler is a mixture of alumina powder and zirconia powder as a ceramic filler. Things are preferred. As a mixture of alumina powder and zirconia powder, a mixture of alumina powder: zirconia powder in a mass ratio of 90:10 to 80:20 is preferable. Moreover, as a mixing ratio of the glass powder and the ceramic filler, a mass ratio of 40:60 to 50:50 is preferable. The glass ceramic composition may be used as the base body 2.

  Here, in order to obtain sufficient heat dissipation in the light emitting element substrate, a thermal via is usually disposed immediately below the light emitting element mounting portion. At that time, a special method is used to suppress the unevenness of the mounting portion caused by the arrangement of the thermal via. However, even if such a method is used, the height of the highest and lowest portions of the unevenness is reduced. At present, the difference is limited to about 1 μm or less.

In the present invention, sufficient heat dissipation is ensured without the provision of thermal vias that cause unevenness in the light emitting element mounting portion according to the above configuration. The difference in height from the lowest portion is equivalent to the surface other than the mounting portion, that is, the surface of the insulating protective layer in the present invention, and is generally 0.5 μm or less.
In other words, in the configuration of the present invention, the flatness of the mounting portion can be easily flattened more easily than when the thermal via is provided, compared to the case where the thermal via is provided while having sufficient heat dissipation. Is. When the flatness is good, the adhesion between the light emitting element and the shipping element mounting portion is improved, the thermal resistance at the interface is reduced, and the heat dissipation is improved.

  The light-emitting element substrate 1 has a frame body 8 on the periphery of the LTCC layer 4 mounting surface so as to form a cavity having a substantially rectangular portion at the center of the mounting surface of the LTCC layer 4 as a bottom surface (hereinafter referred to as “cavity bottom surface”). Have Although the material which comprises the frame 8 is not specifically limited, It is preferable to use the same material as that which comprises the substrate body 2 or the LTCC layer 4. In addition, the light emitting element mounting portion is located at a substantially central portion of the cavity bottom surface. In this example, the light emitting element to be mounted has a substantially rectangular parallelepiped shape, and is mounted so that the long side of the substrate body 2 and the long side of the light emitting element are parallel to each other.

  The light emitting element substrate 1 reaches the main surface 21 side of the substrate body 2 from the upper surface side of the frame body 8 through the frame body 8 and the LTCC layer 4 at the substantially central portions of the two long side surfaces, A cutout portion extending from there to the back surface 23 side of the substrate body 2 has a cutout portion 24 having a semi-cylindrical shape. In this example, the notch 24 is formed on the side surface on the long side, which is a preferred position in the present invention, at a position closest to the light emitting element to be mounted. However, the notch 24 is formed at this position by design. When it is difficult, it is preferable to form it on the side surface as close to the light emitting element as possible in the region where heat generated by the mounted light emitting element is conducted. Furthermore, it is preferable that the notch 24 is formed in a size that does not reach the inner wall of the frame 8.

  Further, although the number of the notches 24 is two in this example, the number can be adjusted as necessary within a range not impairing the effects of the present invention. The shape of the notch 24 is not particularly limited. However, since the notch 24 serves as a fixing part when the substrate body 2 is fixed to the mother board by soldering, it is preferable that the notch 24 be easily fixed by solder.

A first heat radiation layer 9 made of a first heat radiation material is formed on the entire surface of the notch 24. Note that, depending on the design of the light emitting element substrate and the light emitting device in which the light emitting element substrate is used, the first heat dissipation layer 9 is formed only on the surface of the cutout portion of the substrate main body 2 of the surface of the cutout portion 24 or with the substrate main body 2. The LTCC layer 4 may be formed only on the surface of the notch. At least the first heat dissipation layer 9 and the second heat dissipation layer 3 described below are connected to the surface of the notch 24 in the first heat dissipation layer 9, and an area required for fixing the solder is secured. The base body 2 may be formed so as to reach a desired height from the back surface 23 side.
The first heat dissipating material constituting the first heat dissipating layer 9, the film thickness of the first heat dissipating layer 9, and the like can be the same as those of the first heat dissipating layer 9 of the first embodiment.

  In the light emitting element substrate 1, a pair of electrodes included in the light emitting element mounted on the mounting surface of the LTCC layer 4 so that the long side of the substrate body 2 and the long side of the light emitting element are parallel to each other. The element connection terminals 5 that are electrically connected to each other are opposed to both outsides of the short sides of the mounting portion across the mounting portion of the light emitting element so as to be electrically connected to the through conductor 7. A pair is provided.

  Here, the element connection terminal 5, the external connection terminal 6 and the through conductor 7 are electrically connected to the light emitting element → the element connection terminal 5 → the through conductor 7 → the external connection terminal 6 → the wiring circuit of the motherboard. Is not limited to the position and shape of the arrangement shown in FIG. 3 and can be adjusted as appropriate.

  The component connection terminals 5, the external connection terminals 6, and the through conductors 7, that is, the constituent materials of the wiring conductors can be used without particular limitation as long as they are the same constituent materials as the wiring conductors used for the light emitting element substrate. The same materials as those described as the constituent materials used for the wiring conductor in the embodiment can be used. The element connection terminal 5, the external connection terminal 6 and the first heat dissipation layer 9 have a conductive protective layer such as gold plating, nickel plating, nickel / gold plating, etc., if necessary, as in the first embodiment. There may be.

The light emitting element substrate 1 according to the second embodiment of the present invention has been described above. Next, an example of the light emitting device 10 of the present invention using the light emitting element substrate 1 will be described with reference to FIG.
4 is a plan view (a) showing an example of the light emitting device 10 of the present invention using the light emitting element substrate 1 shown in FIG. 3, a cross-sectional view taken along line XX in the plan view (a), and a plan view. It is YY sectional view (c) in figure (a).

  When the light-emitting device 10 in this example is manufactured using the light-emitting element substrate 1, a light-emitting element 11 such as a substantially rectangular parallelepiped light-emitting diode element is formed on the surface on which the LTCC layer 4 is mounted as shown in FIG. Fixed to the light emitting element mounting portion 22 at the substantially central portion of the cavity bottom surface by a die bond agent such as a silicone die bond agent or a metal bond agent so that the long side of the substrate body 2 and the long side of the light emitting element 11 are parallel to each other. Installed. In the light emitting device 10, a pair of electrodes (not shown) included in the light emitting element 11 are electrically connected to the element connection terminals 5 located on the outside thereof via bonding wires 12. Further, a sealing layer 13 is provided so as to fill the cavity so as to cover the light emitting element 11 and the bonding wire 12.

  The light emitting device 10 includes a mother board 31 such as a printed wiring board. On the mother board 31, the substrate body 2 on which the light emitting element 11 is mounted covers a part of the surface of the heat sink 33 formed on the main surface of the mother board. Including the solder layer 32 in a form in which the notch 24 is filled with solder, the solder layer 32 is fixed and mounted.

  The mother board 31 has, for example, an insulating resin layer 35 on the main surface on which the substrate body 2 on which the light emitting element 11 is mounted is made of a metal material, and the wiring circuit 34 and the insulating resin layer 35. The heat sinks 33 are arranged independently without being in contact with each other. The solder layer 32 is formed on the heat sink 33 as described above.

  The solder material constituting the solder layer 32 and the shape of the solder layer 32 can be the same as those of the solder layer 32 in the first embodiment. In addition, the material, size, and shape of the heat sink 33 can be the same as those of the heat sink 33 in the first embodiment.

  In the light emitting device 10, with the above configuration, the heat generated by the light emitting element is easily dissipated by conducting smoothly in the order of the second heat dissipation layer 3 → the first heat dissipation layer 9 → the solder layer 32 → the heat sink 33. Is done.

  Further, the light emitting element substrate 1 is arranged such that the external connection terminal 6 formed on the back surface 23 of the substrate body 2 is electrically connected to a part of the wiring circuit 34 formed on the main surface of the mother board 31. 31 is fixed on the heat sink 33 formed on the main surface by soldering.

  Here, the substrate for a light emitting device of the second embodiment of the present invention can be manufactured by, for example, a manufacturing method described below. In addition, about the member used for manufacture, the same code | symbol as the member of a finished product is attached | subjected and demonstrated.

(1) Production of Green Sheet and Formation of Notch and Through Hole First, the side on which the light emitting element is mounted, which constitutes the substrate body 2 of the light emitting element substrate using a glass ceramic composition containing glass powder and a ceramic filler. A substantially flat substrate main body green sheet 2 having the main surface 21 as a main surface 21, a LTCC layer green sheet 4 constituting the LTCC layer 4 of the light emitting element substrate, and a frame green sheet constituting the frame 8. 8 is produced.

  As a glass ceramic composition containing glass powder and ceramic filler used for the production of each green sheet, at least the glass ceramic composition used for production of the LTCC layer green sheet 4 has reflectivity when used as a sintered body. The composition described above is used. The frame green sheet 8 and the substrate main body green sheet 2 may be made of the same composition as the LTCC layer green sheet 4, or in the preparation of the substrate main body green sheet 2 of the first embodiment. You may make with the composition similar to having demonstrated.

  Each of these green sheets prepares a slurry by adding a binder and, if necessary, a plasticizer, a dispersant, a solvent, etc. to a glass ceramic composition containing glass powder and a ceramic filler, and this is prescribed by a doctor blade method or the like. It can manufacture by shape | molding in the shape of a sheet | seat of thickness, and the sheet form, and making it dry.

Next, for each of the green sheet 2 for substrate body, the green sheet 4 for LTCC layer, and the green sheet 8 for the frame body obtained above, the substantially central portion of the two long side surfaces is formed from the upper surface side of each green sheet. A notch portion 24 is formed by notching a normal method so as to reach the back surface. In this example, the notch portion 24 is formed so that the notch shape is a semi-cylindrical shape. Further, depending on the thickness of the substrate main body green sheet 2, LTCC layer green sheet 4, and frame body green sheet 8, the notch 24 may be formed after lamination.
Furthermore, through holes for forming through conductors 7 penetrating from the upper surface side of each green sheet to the back surface are formed in a predetermined size at two predetermined positions on the green sheet 2 for the substrate body and the green sheet 4 for the LTCC layer. Form by the method.

(2) Formation of Wiring Conductor Paste Layer / Metal Paste Layer for Heat Dissipation Layer Next, a predetermined wiring conductor paste layer is formed at predetermined positions on the substrate body green sheet 2 and LTCC layer green sheet 4 obtained in (1) above. Form. A second heat dissipating layer metal paste layer is further formed on the substrate body green sheet 2.

  In the LTCC layer green sheet 4, a through conductor paste layer 7 constituting a part of the through conductor 7 is formed in the two through holes prepared in the above (1), and the through conductor is formed on the surface on which the light emitting element is mounted. The element connection terminal paste layer 5 is formed in a substantially rectangular shape so as to cover the paste layer 7 for use. The LTCC layer green sheet 4 further includes a first heat release on each surface of the notch portions 24 of the two LTCC layer portions formed in (1) above according to the design of the light emitting element substrate, the light emitting device, and the like. A layer metal paste layer 9 is formed by screen printing.

  Regarding the green sheet 2 for a substrate body, the through-conductor paste layer 7 constituting a part of the through-conductor 7 is formed in the two through-holes produced in the above (1), and the through-conductor paste layer 7 is electrically connected to the back surface 23. The external connection terminal conductor paste layer 6 to be connected is formed. The substrate body green sheet 2 is further formed by screen printing on the surfaces of the notches 24 of the two substrate body portions formed in (1) above by screen printing.

  Next, the pair of through conductor paste layers 7 on the main surface 21 of the substrate body green sheet 2 having the wiring conductor paste layer and the base body portion notch portion and the first heat radiation layer metal paste layer 9 formed on the surface thereof. A second heat dissipating layer metal paste layer 3 containing a heat dissipating material is formed by screen printing on a portion where the heat dissipating member is disposed and in the vicinity of the periphery and the peripheral portion of the main surface. More specifically, the second heat dissipating layer metal paste layer 3 has an end in a direction corresponding to the short side direction of the substrate body green sheet 2 at a substantially central portion on the main surface 21 of the substrate body green sheet 2. The edge reaches the notch 24 (base body portion) formed on the side surface and is connected to the first heat dissipation layer 9, and the edge in the direction corresponding to the long side direction of the substrate body green sheet 2 is Each of the pair of penetrating conductor paste layers 7 is provided so as to be located on the inner side by about 1/3 of the distance between them.

  Further, the frame green sheet 8 has a first surface formed on each surface of the notches 24 of the two frame portions formed in the above (1) according to the design of the light emitting element substrate, the light emitting device, and the like. A metal paste layer 9 for heat dissipation layer is formed by screen printing.

  For the wiring conductor paste layer formation, the element connection terminal paste, the through conductor paste, the wiring conductor paste such as the external connection terminal conductor paste, and the first and second heat radiation layer metal pastes are described above. The same ones as described in the first embodiment can be used, and the formation method can be the same.

(3) Stacking of green sheets The first heat dissipating layer metal paste layer 9 and the wiring conductor paste layer (element connection terminal paste) formed on the surface of the cutout 24 of the base body portion obtained in the steps up to (2) above. Cutout portion of the LTCC layer portion on the main surface of the green sheet 2 for the substrate body having the layer 5, the external connection terminal conductor paste layer 6 and the through conductor paste layer 7) and the second heat radiation layer metal paste layer 3 24 and LTCC layer green sheet with wiring conductor paste layer, having first heat dissipation layer metal paste layer 9 on its surface, or notch portion 24 but not first heat dissipation layer metal paste layer 9 4 is laminated with the surface (light emitting element mounting surface) on which the element connection terminal paste layer 5 is formed facing upward. Furthermore, the cutout portion 24 of the frame portion and the first heat dissipation layer metal paste layer 9 on the surface thereof are formed thereon, or the cutout portion 24 is provided with the first heat dissipation layer metal paste layer 9. No, green frame sheet 8 is laminated. As a result, a green sheet laminate having a shape in which the LTCC layer 4 has a cavity on the mounting surface and the bottom surface forms a region for mounting the light emitting element is obtained as the green light emitting element substrate 1.

(4) Firing After the step (3), the obtained unsintered light emitting device substrate 1 is degreased to remove a binder or the like as necessary, and a glass ceramic composition or the like is sintered. Firing (firing temperature: 800 to 930 ° C.) is performed. This firing step can be performed in exactly the same way as described in (5) Firing in the method for producing a light emitting element substrate of the first embodiment.

  In this way, the unsintered light emitting element substrate 1 is fired to obtain the light emitting element substrate 1. After firing, the element connection terminals 5, the external connection terminals 6, and the first heat radiation layer 9 as a whole are necessary. In general, a conductive protective layer used for protecting a conductor in a substrate for a light-emitting element, such as gold plating, nickel plating, nickel / gold plating, etc., may be disposed so as to cover the substrate.

  The manufacturing method of the light emitting element substrate according to the second embodiment of the present invention has been described above. However, the substrate main body green sheet 2, the LTCC layer green sheet 4, and the frame body green sheet 8 are not necessarily a single green. It is not necessary to consist of sheets, and a laminate of a plurality of green sheets may be used. Further, the order of forming each part can be changed as appropriate as long as the light emitting element substrate can be manufactured.

(5) Production of Light-Emitting Device The method for producing the light-emitting device 10 shown in FIG. 4 by using the light-emitting element substrate 1 of the second embodiment is not particularly limited, and the light-emitting element 11 is used for a light-emitting element. All of the conventional methods, such as a method of mounting on the substrate 1, a method of electrical connection such as wire bonding, a method of forming the sealing layer 13 using a sealing agent, and a method of fixing the light emitting element substrate 1 to the mother board 31 by soldering, are all conventional. A known method is applicable.

  The light-emitting element substrate of the present invention is usually used when producing a wiring substrate such as a light-emitting element substrate, depending on its size, regardless of the first and second embodiments. It may be produced by a method of producing a multi-piece connection substrate and obtaining individual wiring substrates by obtaining a step of dividing the connection substrate. In that case, as long as the timing of division is after the firing, it may be before the light emitting element is mounted, or may be after the light emitting element is mounted and before being soldered to the mother board.

  As described above, the embodiment of the light emitting element substrate according to the present invention is an example in which LTCC is used as the constituent material of the substrate body, and the case where the glass layer is used as the insulating protective layer is described as the first embodiment. The case where a reflective LTCC layer is used as the protective protective layer is described as a second embodiment with reference to an example of a light emitting element substrate and a light emitting device using the same, respectively. The light emitting device is not limited to these. As long as it does not contradict the spirit of the present invention, the configuration can be changed as necessary.

  For example, each of the examples of the light emitting element substrate of the first embodiment and the second embodiment described above has a notch portion on the side surface of the substrate main body which is preferable in the present invention, and the first heat radiation on the surface thereof. In the light emitting element substrate according to the present invention, the connection between the second heat dissipation layer formed on the main surface of the substrate body and the first heat dissipation layer formed on the side surface is ensured. As long as it is necessary, the first heat dissipation layer may be formed on the side surface of the substrate body without forming the notch as necessary.

  As an example, FIG. 5 shows a light emitting device having a structure in which the first heat dissipation layer is formed on the side surface of the substrate body without forming the notch in the second embodiment of the light emitting device substrate of the present invention using the LTCC substrate. The element substrate 1 is shown. 5A is a plan view, FIG. 5B is a cross-sectional view taken along the line XX in the plan view (a), and FIG. 5C is a cross-sectional view taken along the line YY in the plan view (a).

  The light-emitting element substrate 1 shown in FIG. 5 has no notch at the side surface where the notch is formed in the light-emitting element substrate 1 shown in FIG. 3 and the first heat dissipation layer 9 is formed on the surface. The first heat dissipation layer 9 is formed and the shape of the second heat dissipation layer 3 formed on the main surface 2 of the substrate body 2 is connected to the first heat dissipation layer 9 located on the side surface. Thus, it is the same as the light emitting element substrate 1 shown in FIG. 3 except that only the corresponding part is formed so as to reach the side surface.

  Even in the case of manufacturing a light-emitting device using the light-emitting element substrate of the present invention that does not have such a notch, the light-emitting element is usually mounted on the light-emitting element substrate, and electrical wiring, sealing layer formation, and the like are performed. Thereafter, in the same manner as described above, a solder layer is formed by a normal method from the first heat dissipation layer to the heat sink of the motherboard, so that the light emitting element substrate on which the light emitting element is mounted on the motherboard can be mounted. In the light-emitting device thus obtained, the heat generated by the light-emitting element is the same as that of the light-emitting device using the light-emitting element substrate having the notch, but the second heat dissipation layer → the first heat dissipation layer → the solder. Layer-> Conducts smoothly to the heat sink of the motherboard and is easily dissipated.

  According to the light emitting element substrate of the present invention, it is economically advantageous compared to thermal vias and can ensure flatness, and when the light emitting device is formed, the light emitting element sufficiently generates heat together with the other structures of the light emitting device. Can be dissipated.

  Further, by using the substrate for a light emitting element of the present invention, sufficient heat dissipation can be obtained without using a thermal via that deteriorates the flatness of the substrate surface, so that the light emitting element and the substrate can be easily bonded. There are also advantages. Further, according to the present invention, by mounting the light emitting element on such a light emitting element substrate and mounting the light emitting element on the mother board, the heat generated by the light emitting element is sufficiently dissipated and the light emitting device has sufficient light emission luminance. Is obtained. Such a light-emitting device of the present invention can be suitably used as a backlight for mobile phones, large liquid crystal displays, etc., illumination for automobiles or decoration, and other light sources.

Examples of the present invention will be described below. The present invention is not limited to these examples.
[Example 1]
A test light-emitting device having the same structure as that shown in FIG. 2 was produced by the method described below. In addition, the same code | symbol used for a member before and behind baking was used similarly to the above.

First, a substrate main body green sheet 2 and a frame green sheet 8 for manufacturing the substrate main body 2 of the light emitting element substrate 1 were prepared. Each green sheet has SiO ₂ of 60.4 mol%, B ₂ O ₃ of 15.6 mol%, Al ₂ O ₃ of 6 mol%, CaO of 15 mol%, K ₂ O of 1 mol%, and Na ₂ O of 2 mol%. The raw materials were blended and mixed so that the raw material mixture was put in a platinum crucible and melted at 1600 ° C. for 60 minutes, and then the molten glass was poured out and cooled. This glass was pulverized for 40 hours by an alumina ball mill to produce a glass powder for a substrate body. In addition, ethyl alcohol was used as a solvent for pulverization.

  The substrate body glass powder is 40% by mass, alumina filler (made by Showa Denko, trade name: AL-45H) 51% by weight, zirconia filler (made by Daiichi Rare Element Chemical Industries, trade name: HSY-3F-J). ) A glass ceramic composition was manufactured by blending and mixing so as to be 9% by mass. 50 g of this glass ceramic composition, 15 g of an organic solvent (toluene, xylene, 2-propanol, 2-butanol mixed at a mass ratio of 4: 2: 2: 1), plasticizer (di-2-ethylhexyl phthalate) 2.5 g of polyvinyl butyral (trade name: PVK # 3000K, manufactured by Denka) as a binder and 5 g of a dispersant (trade name: BYK180, manufactured by Big Chemie) were further blended and mixed to prepare a slurry.

  The slurry is applied on a PET film by a doctor blade method, and dried green sheets are laminated to form a substantially flat plate-like green sheet 2 for substrate body having a thickness after firing of 0.5 mm. A green body sheet 8 having a shape similar to that of the green sheet 2 for a substrate body, a substantially rectangular shape inside the frame, and a frame height of 0.5 mm after firing was manufactured. In this embodiment, the light-emitting element substrate 1 is manufactured as a multi-piece connecting substrate, and is divided into one piece after firing, which will be described later, and the light-emitting element substrate has an outer size of 3 mm × 1.5 mm. It was set to 1. The following description explains one division which becomes one light-emitting element substrate 1 after the division among the multi-piece connection substrates.

  On the other hand, conductive powder (manufactured by Daiken Chemical Industry Co., Ltd., trade name: S550) and ethyl cellulose as a vehicle are blended at a mass ratio of 85:15, and α-terpineol as a solvent so that the solid content is 85 mass%. Then, the paste was kneaded for 1 hour in a porcelain mortar, and further dispersed three times with a three roll to produce a wiring conductor paste.

  Further, the metal paste for the heat radiation layer is composed of silver powder (manufactured by Daiken Chemical Industry Co., Ltd., trade name: S400-2) and ethyl cellulose as the vehicle for both the first heat radiation layer and the second heat radiation layer. After blending in a ratio of 90:10 and dispersing in α-terpineol as a solvent so that the solid content is 87% by mass, kneading in a porcelain mortar for 1 hour, and further dispersing three times with three rolls Manufactured.

  A through hole having a diameter of 0.3 mm was formed in a portion corresponding to the through conductor 7 of the substrate main body green sheet 2 using a hole puncher. Furthermore, the notch shape is 0.3 mm in radius by the punching machine of UHT so that the substantially central part of the side surface on the two long sides of the green sheet 2 for the substrate main body extends from the main surface 21 side to the back surface 23 side, respectively. A cutout portion 24 of the substrate main body portion was formed by cutting out to form a semi-cylindrical shape.

  The through-conductor paste layer 7 is formed by filling the two through-holes of the green sheet 2 for substrate obtained above with a wiring conductor paste by screen printing, and the main conductor paste layer 7 is covered so as to cover the through-conductor paste layer 7. The element connection terminal paste layer 5 was formed on the surface 21, and the external connection terminal conductor paste layer 6 was formed on the back surface 23. Next, on the entire surface of the two substrate body partial cutouts formed as described above of the substrate body green sheet 2, the film thickness after firing using the first metal paste for heat dissipation layer is 30 μm. The first metal paste layer 9 for heat dissipation layer was formed by screen printing.

  Further, on the main surface 21 of the substrate main body green sheet 2, the peripheral portion of the main surface 21 of the substrate main body green sheet 2, the portion where the pair of element connection terminal paste layers 5 are disposed, and the vicinity thereof. The first metal paste layer for heat radiation layer formed in the cutout portion 24 in the short side direction has a width of approximately 0.75 mm in the long side direction of the substrate main body green sheet 2 in the long side direction. The second heat dissipating layer metal paste layer 3 was formed by screen printing so as to be connected to 9, so that the film thickness after firing was 35 μm to obtain a green sheet 2 for a substrate body with a conductor paste layer. Moreover, it was confirmed that the surface roughness Ra of the 2nd heat dissipation layer 3 after baking was 0.08 micrometer from the measurement by Tokyo Seimitsu Co., Ltd. Surfcom 1400D.

  Further, in the obtained green sheet 2 for substrate main body with conductor paste layer, the element connection on the main surface 21 of the green sheet 2 for substrate main body is covered, covering the whole including the edge of the second metal paste layer 3 for heat radiation layer. The film thickness after baking the overcoat glass paste layer 4 by screen printing on the main surface 21 of the substrate main body green sheet 2 excluding the terminal paste layer 5 and the vicinity thereof and the peripheral portion of the main surface is 20 μm. Formed. In addition, the surface roughness Ra of the overcoat glass layer 4 after firing was confirmed to be 0.01 μm from measurement with Surfcom 1400D manufactured by Tokyo Seimitsu Co., Ltd.

In addition, the glass powder for glass films used for preparation of overcoat glass paste was manufactured as follows. First, raw materials are blended and mixed so that SiO ₂ is 81.6 mol%, B ₂ O ₃ is 16.6 mol%, and K ₂ O is 1.8 mol%, and this raw material mixture is put in a platinum crucible at 1600 ° C. Then, the molten glass was poured out and cooled. This glass was pulverized with an alumina ball mill for 8 to 60 hours to obtain a glass powder for glass film.

  In this porcelain mortar, the glass powder for the overcoat glass layer was blended so as to be 60% by mass and the resin component (containing ethyl cellulose and α-terpineol at a mass ratio of 85:15) to 40% by mass. Were kneaded for 1 hour and further dispersed three times with three rolls to prepare an overcoat glass paste.

  On the other hand, the frame green sheet 8 also has a notch shape with a radius of 0.3 mm by a punching machine from UHT so that the substantially central portions of the two long side surfaces extend from the upper surface side to the back surface side. To form a semi-cylindrical shape of the frame body, and the notch 24 of the frame body portion is formed, and the film thickness after firing using the first metal paste for heat dissipation layer is 30 μm on the entire surface. The first metal paste layer 9 for heat dissipation layer was formed by screen printing.

  On the main surface 21 of the substrate main body green sheet 2 with conductor paste layer + overcoat glass paste layer obtained above, the first green sheet 8 for frame with metal paste layer for heat dissipation layer obtained above. Were stacked to obtain an unfired multi-piece connected substrate having a plurality of sections of the unsintered light emitting device substrate 1.

  After putting the cut line for division so that each section of the unsintered light emitting element substrate 1 has an outer size of 3 mm × 1.5 mm after firing, in the unfired multi-piece connection substrate obtained above, Degreasing was carried out by holding at 550 ° C. for 5 hours, and further baking was carried out at 870 ° C. for 30 minutes to produce a multi-piece connection substrate. The obtained multi-piece connection substrate was divided along the cut line to produce a test light-emitting element substrate 1.

  A light-emitting device 10 is manufactured by mounting a 2-wire type light-emitting diode element on the light-emitting element mounting portion 22 of the main surface 21 between the pair of element connection terminals 5 on the test light-emitting element substrate 1 manufactured above. did. Specifically, the light emitting diode element 11 (manufactured by Showa Denko KK, trade name: GQ2CR460Z) is made of a die-bonding material (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: SMP-2800), and the long side of the light emitting element 11 is the substrate body 2. The pair of electrodes included in the light emitting element 11 was electrically connected to the element connection terminal 5 and the bonding wire 12, respectively, so as to be parallel to the long side.

  Furthermore, it sealed so that the sealing layer 13 shown in FIG. 2 might be comprised using the sealing agent (The Shin-Etsu Chemical Co., Ltd. make, brand name: SCR-1016A). As the sealant, a phosphor (made by Kasei Optonix, trade name P46-Y3) containing 20% by mass with respect to the sealant was used.

The light emitting element 11 is mounted on a mother board 31 having a configuration in which an insulating resin layer 35 is provided on a metal substrate, and a wiring circuit 34 and a heat sink 33 are independently provided on the insulating resin layer 35 without being in contact with each other. The light emitting element substrate 1 was fixed by soldering so that the two cutouts 24 were filled with a solder material and the solder layer 32 was formed on the heat sink 33 of the mother board 31. The height of the formed solder layer 32 was 0.8 mm, and the adhesion area of the mother board 31 to the heat sink 33 was 0.07 mm ² . With this soldering, a part of the wiring circuit 34 included in the mother board and the external connection terminal 6 included in the light emitting element substrate 1 were electrically connected.

[Comparative Example 1]
A light emitting device having a conventional configuration was fabricated as Comparative Example 1 in the same manner as in Example 1 except that the cutout 24 and the first heat dissipation layer were not formed on the surface thereof in Example 1.

<Evaluation>
In the light emitting device of Example 1 when the thermal resistance of the light emitting device obtained in Example 1 and Comparative Example 1 was measured by the following method and the thermal resistance in the conventional light emitting device of Comparative Example 1 was 100%. Thermal resistance was expressed as a percentage. The results are shown in Table 1.

[Thermal resistance]
The thermal resistance of the light emitting element substrate in the light emitting device was measured using a thermal resistance measuring instrument (trade name: TH-2167, manufactured by Fluorescent Sound Electric Co., Ltd.). The applied current was 350 mA, the current was passed until the voltage drop was saturated, the saturation temperature was calculated from the dropped voltage and the temperature coefficient derived from the temperature-voltage drop characteristics of the light-emitting diode element, and the thermal resistance was obtained.

[Example 2]
A test light-emitting device having the same structure as that shown in FIG. 4 was produced by the method described below. In addition, the same code | symbol used for a member before and behind baking was used similarly to the above.
First, a substrate main body green sheet 2, an LTCC layer green sheet 4, and a frame green sheet 8 for manufacturing the substrate main body 2 of the light emitting element substrate 1 were prepared. The substrate green sheet 2 and the frame green sheet 8 were prepared in the same manner as in Example 1. The LTCC layer green sheet 4 was manufactured so that the outer dimension was substantially a flat plate shape similar to that of the green sheet 2 for a substrate body, and the film thickness after firing was 0.1 mm. Also in this example, as in Example 1 above, the light-emitting element substrate 1 was manufactured as a multi-piece connecting substrate, and was divided into pieces after firing, which will be described later. A light-emitting element substrate 1 having a size was obtained. The following description explains one division which becomes one light-emitting element substrate 1 after the division among the multi-piece connection substrates.

Moreover, the wiring conductor paste and the first and second heat radiation layer metal pastes were produced in the same manner as in Example 1.
A through hole having a diameter of 0.3 mm was formed in a portion corresponding to the through conductor 7 of the substrate main body green sheet 2 using a hole puncher. Furthermore, the notch shape is 0.3 mm in radius by the punching machine of UHT so that the substantially central part of the side surface on the two long sides of the green sheet 2 for the substrate main body extends from the main surface 21 side to the back surface 23 side, respectively. A cutout portion 24 of the substrate main body portion was formed by cutting out to form a semi-cylindrical shape.

  The through-conductor paste layer 7 is formed by filling the two through holes of the green sheet 2 for substrate obtained above with a wiring conductor paste by a screen printing method, and the external connection terminal conductor paste layer is formed on the back surface 23. 6 was formed. Next, on the entire surface of the two substrate body partial cutouts formed as described above of the substrate body green sheet 2, the film thickness after firing using the first metal paste for heat dissipation layer is 30 μm. The first metal paste layer 9 for heat dissipation layer was formed by screen printing.

  Further, on the main surface 21 of the substrate main body green sheet 2, the peripheral portion of the main surface 21 of the substrate main body green sheet 2, the portion where the pair of through conductor paste layers 7 are disposed, and the vicinity of the periphery. The first heat dissipating layer metal paste layer 9 having a width of approximately 0.75 mm in the long side direction of the substrate body green sheet 2 in the excluded region and having a width of about 0.75 mm in the short side direction. The second heat dissipating layer metal paste layer 3 was formed by screen printing so that the film thickness after firing was 35 μm so as to obtain a green sheet 2 for a substrate body with a conductor paste layer. Moreover, it was confirmed that the surface roughness Ra of the 2nd heat dissipation layer 3 after baking was 0.08 micrometer from the measurement by Tokyo Seimitsu Co., Ltd. Surfcom 1400D.

  In the LTCC layer green sheet 4, a through hole having a diameter of 0.3 mm was formed in a portion corresponding to the through conductor 7 using a hole puncher. Further, the substantially center part of the two long side surfaces of the LTCC layer green sheet 4 is respectively cut from the main surface 21 side to the back surface 23 side by a punching machine of UHT with a radius of 0.3 mm. A cutout portion 24 of the LTCC layer portion was formed by cutting out to form a semi-cylindrical shape.

  The two through holes of the LTCC layer green sheet 4 obtained above are filled with a paste for wiring conductor by screen printing to form a through conductor paste layer 7, and the through conductor is formed on the surface on which the light emitting element is mounted. The element connection terminal paste layer 5 was formed in a substantially rectangular shape so as to cover the paste layer 7 by screen printing. Next, on the entire surface of the two LTCC layer partial notches formed as described above of the LTCC layer green sheet 4, the first heat dissipation layer metal paste is used so that the film thickness after firing becomes 30 μm. The heat dissipation layer metal paste layer 9 of 1 was formed by screen printing to obtain an LTCC layer green sheet 4 with a conductive paste layer.

  On the other hand, the frame green sheet 8 also has a notch shape with a radius of 0.3 mm by a punching machine from UHT so that the substantially central portions of the two long side surfaces extend from the upper surface side to the back surface side. To form a semi-cylindrical shape of the frame body, and the notch 24 of the frame body portion is formed, and the film thickness after firing using the first metal paste for heat dissipation layer is 30 μm on the entire surface. The first metal paste layer 9 for heat dissipation layer was formed by screen printing.

  The surface (light emitting element mounting surface) on which the element connection terminal paste layer 5 is formed on the main surface 21 of the green sheet 2 for a substrate body with a conductor paste layer obtained above, on the LTCC layer green sheet 4 with a conductor paste layer. Laminated with the top facing up. Furthermore, the green sheet 8 with the metal paste layer for the first heat radiation layer obtained above is laminated thereon, and a plurality of unfired multi-piece connection connected with a plurality of unsintered light emitting element substrates 1 are connected. A substrate was obtained.

After putting the cut line for division so that each section of the unsintered light emitting element substrate 1 has an outer size of 3 mm × 1.5 mm after firing, in the unfired multi-piece connection substrate obtained above, Degreasing was carried out under the condition of holding at 550 ° C. for 5 hours, and further baking was carried out at 870 ° C. for 30 minutes to produce a multi-piece connection substrate. The obtained multi-piece connection substrate was divided along the cut line to produce a test light-emitting element substrate 1. The surface roughness Ra of the surface of the LTCC layer 4 in the obtained light emitting device substrate 1 was confirmed to be 0.01 μm from measurement with Surfcom 1400D manufactured by Tokyo Seimitsu Co., Ltd.
A light emitting device of Example 2 was produced in the same manner as in Example 1 except that the test light emitting element substrate 1 produced above was used.

[Comparative Example 2]
In Example 2, a light emitting device having a conventional configuration was produced as Comparative Example 2 in the same manner as Example 2 except that the cutout portion 24 and the first heat dissipation layer were not formed on the surface thereof.

<Evaluation>
In the light emitting device of Example 2 when the thermal resistance of the light emitting devices obtained in Example 2 and Comparative Example 2 was measured by the above method and the thermal resistance in the conventional light emitting device of Comparative Example 2 was 100%. Thermal resistance was expressed as a percentage. The results are shown in Table 2.

[Example 3]
The light-emitting element substrate 1 has the same configuration as that of the light-emitting element substrate 1 used in the light-emitting device of Example 1 except that it does not have the overcoat glass layer 4. FIG. A light-emitting element substrate 1 showing a cross-sectional view taken along a line and a cross-sectional view taken along a line Y-Y was manufactured.
A light emitting device of Example 3 was produced in the same manner as in Example 1 except that the test light emitting element substrate 1 produced above was used.

[Comparative Example 3]
A light emitting device having a conventional configuration was manufactured as Comparative Example 3 in the same manner as in Example 3 except that in Example 3 above, the cutout portion 24 and the first heat dissipation layer were not formed on the surface thereof.

<Evaluation>
In the light emitting device of Example 3 when the thermal resistance of the light emitting devices obtained in Example 3 and Comparative Example 3 was measured by the above method and the thermal resistance in the conventional light emitting device of Comparative Example 3 was 100%. Thermal resistance was expressed as a percentage. The results are shown in Table 3.

  According to the substrate for a light-emitting element of the present invention, the heat dissipation from the light-emitting element can be dissipated without an increase in the manufacturing process such as a thermal via or a heat-dissipating member that requires a large amount of silver or the like to be filled therein. Is sufficiently possible, and when the light emitting device is formed, an excessive temperature rise of the light emitting element can be suppressed and light can be emitted with high luminance. The light-emitting device of the present invention using such a light-emitting element substrate can be suitably used as a backlight for mobile phones, large liquid crystal displays, etc., illumination for automobiles or decoration, and other light sources.

DESCRIPTION OF SYMBOLS 1 ... Light emitting element substrate, 2 ... Board | substrate body, 3 ... 2nd thermal radiation layer, 4 ... Insulating protective layer (glass layer, LTCC layer), 5 ... Element connection terminal, 6 ... External connection terminal, 7 ... Through-conductor , 8 ... frame, 9 ... first heat radiation layer 10 ... light emitting device, 11 ... light emitting element, 12 ... bonding wire, 13 ... sealing layer 21 ... main surface, 22 ... light emitting element mounting portion, 23 ... back surface, 24 ... notch 31 ... motherboard, 32 ... solder layer, 33 ... heat sink, 34 ... wiring circuit, 35 ... insulating resin layer

Claims (7)

A substrate body made of an inorganic insulating material having a part of a wiring conductor for electrically connecting an electrode of the light emitting element to a wiring circuit of a motherboard on a main surface on which the light emitting element is mounted;
A first heat radiating formed from the main surface side to the opposite surface side, which becomes a fixing portion when soldered to the mother board, on a side surface in a region where heat generated by the light emitting element of the substrate body is conducted. A first heat dissipation layer made of a material;
A second surface formed on the main surface of the substrate body includes at least a mounting portion of the light emitting element, is electrically insulated from a part of the wiring conductor, and is connected to the first heat dissipation layer. And a second heat dissipation layer made of a heat dissipation material.   The light emitting element substrate according to claim 1, wherein the first heat radiation layer is formed at a position at a shortest distance from the light emitting element mounting portion on the side surface of the substrate main body.   3. The light-emitting element according to claim 1, wherein the substrate body has a notch portion at a side surface position where the first heat dissipation layer is formed, and the first heat dissipation layer is formed on a surface of the notch portion. substrate.   The substrate for a light emitting device according to claim 1, wherein the inorganic insulating material is a sintered body of a glass ceramic composition containing glass powder and a ceramic filler.   The substrate for a light emitting device according to claim 1, wherein the substrate body does not have a thermal via.   The light emitting element substrate according to any one of claims 1 to 5, wherein the first heat dissipation material and the second heat dissipation material are metal materials containing silver. The light emitting element substrate according to any one of claims 1 to 6,
A light emitting element mounted on the light emitting element substrate;
A motherboard having a heat sink and a wiring circuit on which the light emitting element substrate is mounted;
A solder layer for fixing the light emitting element substrate to the mother board, the solder layer formed to connect the first heat dissipation layer and the heat sink;
A light emitting device comprising:

Images