JP4789671B2 - WIRING BOARD FOR LIGHT EMITTING ELEMENT AND LIGHT EMITTING DEVICE - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring board for light emitting elements and the light emitting device which is miniaturizable and superior in heat dissipation performance and mounting reliability. <P>SOLUTION: An insulation base 1 and a metal body 8 comprise mutually vertically superposed and meshed steps so that the base 1 and the body 8 bond only at the mutually superposed bonded surfaces 8a, 12a of the steps, the inner through walls near these bonded surfaces and the side wall of the metal body. This greatly reduces the vertically superposed width of the steps and enough holds the sealing performance. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

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

  Conventionally, light emitting devices using LEDs have been used for various applications because of their extremely high luminous efficiency and the small amount of heat generated with light emission compared to incandescent bulbs. However, since it emits less light than incandescent bulbs, fluorescent lamps, etc., it is used as a light source for display rather than for illumination, with an energization amount of about 30 mA, an LED size of about 0.1 mm, and a heat generation amount of 0. It was very small, about .01 W (see, for example, Patent Document 1).

  In recent years, with the increase in brightness and whiteness of light-emitting devices using light-emitting elements, light-emitting devices are often used for backlights of mobile phones, large liquid crystal TVs, and the like. It is also often used for small lighting such as indirect lighting and spotlights. However, as the brightness of the light emitting element is increased, the size of the LED is 1 mm and the amount of heat generated from the LED is dramatically increased to 5 W. In order to eliminate the decrease in the brightness of the light emitting element, such heat is used. There is a need for a light-emitting element wiring board having a high heat dissipation property that dissipates more rapidly than the element.

  For this reason, in a semiconductor device incorporating a semiconductor element, a heat sink has been provided in order to efficiently cool the semiconductor element (see, for example, Patent Document 2). As a structure for dissipating heat from the circuit board, a wiring board structure with a built-in heat sink has been proposed (see, for example, Patent Document 3).

  On the other hand, a light emitting device mounted on a mobile phone or the like has a very strong demand for small size, and the size of the issuing device itself is as small as about 5 mm □, and further miniaturization is expected in the future. In addition, when applied as an alternative for lighting, it is necessary to arrange a large number of light emitting devices in a narrow space from the viewpoint of increasing the amount of emitted light, so that the light emitting device can be downsized even when applied to lighting applications. Become very important.

Against this backdrop, it is inevitable that the output will go higher and higher in the future. As described above, the light emitting element can be used for high heat generation, and the light emitting device can be miniaturized and the wiring on which the light emitting element is mounted. Miniaturization of the substrate and high thermal conductivity are important. And in such a light emitting element wiring board with a strong demand for small size, an excessive heat dissipating member is not necessary, and an extra area for joining the heat dissipating member must also be deleted.
JP 2002-134790 A Japanese Patent Laid-Open No. 10-321759 JP 2005-33194 A

  However, in the invention described in Patent Document 2, a heat sink is used to efficiently cool the heat of the semiconductor chip. However, in order to maintain sealing performance, the bonding layer width between the insulating base and the heat sink is set to 1 mm or more. Therefore, the present situation is that it cannot be applied to miniaturization of a wiring board including a heat sink.

  In addition, when a resin is used as the insulating layer and a light emitting element is used as the semiconductor element as in Patent Document 3, the thermal expansion coefficient of the insulating layer is large, so that the difference in thermal expansion between the heat sink and the insulating layer can be reduced. Although a heat sink made of a metal having a high thermal conductivity such as Cu can be used, it is difficult to form fine wiring, and the thermal conductivity of the resin is very low, so a large heat sink must be used. In other words, light-emitting devices with a built-in heat sink having a very large size compared to light-emitting elements are in circulation.

  In other words, a wiring board that is inexpensive, small, excellent in heat dissipation, and excellent in mounting reliability has not yet been provided.

  Accordingly, an object of the present invention is to provide a light emitting element wiring board and a light emitting device which are inexpensive, small in size and excellent in heat dissipation.

In the wiring board for light emitting device of the present invention, a conductor layer is formed on at least one of the surface or the inside of a flat ceramic substrate, and a metal body is inserted into a through-hole penetrating between the main surfaces of the insulating substrate. a said insulating substrate and the wiring substrate for light-emitting element and the metal body is bonded by bonding material is, the inner wall of the through hole having a stepped Rutotomoni, the side surface of the metal body, the step up and down and step meshing is provided so as to overlap, below the upper and the joint surface from the bonding surfaces of the upper and lower joint surfaces facing each other in a direction other and the through-hole side of the step of the step and the metal body of the through hole in at least one side, prior Symbol inner wall of the through hole and said metal body, wherein are joined only in the vicinity of the joint surface, and the distance of the joining surfaces facing each other circumferentially of the through-hole Characterized in that it changes toward.

In the light-emitting element wiring board of the present invention, it is preferable that a bonding metal layer for bonding the bonding material is disposed on the insulating base.

  In addition, the light emitting element wiring board of the present invention is preferably a sintered metal body in which the metal surface is embedded in the insulating base.

  In the light emitting element wiring board of the present invention, it is desirable that the width of the bonding surface is less than 1 mm.

  The light emitting device of the present invention is characterized in that the light emitting element is mounted on the light emitting element wiring board described above.

According to the light emitting element wiring board of the present invention, it is possible to maintain Rutotomoni can significantly reduce the overlapping width stepped difference, sufficient sealing properties. Therefore, it is possible to reduce the size and heat dissipation of the light emitting element wiring board.

  Moreover, according to the wiring board for light emitting elements of the present invention, the bonding material can be arranged between the insulating base and the metal body with high accuracy by arranging the metal surface for bonding on the insulating base.

  Further, according to the wiring board for a light emitting element of the present invention, since the metal surface is formed of sintered metal embedded in the insulating base, the metal surface can be simultaneously formed in the firing process of the insulating base. Man-hours and costs can be reduced.

  Moreover, according to the wiring board for light emitting elements of the present invention, the width of the bonding surface can be easily made less than 1 mm, and the wiring board for light emitting elements having a small size and excellent sealing properties is obtained.

  According to the light emitting device of the present invention in which the light emitting element is mounted on the wiring substrate for the light emitting element of the present invention described above, the heat generation from the light emitting element can be quickly discharged outside the device, so that the luminance reduction due to the heat generation is suppressed. it can.

  Moreover, according to the light-emitting device of the present invention in which the light-emitting element is mounted on the light-emitting element wiring substrate of the present invention described above, the light-emitting device is small and excellent in heat dissipation.

  The light emitting element wiring board of the present invention has, for example, a flat insulating base 1 and a through hole formed so as to penetrate the front and back surfaces of the insulating base 1 as shown in FIGS. 1 (a) and 1 (b). A connection terminal 3 between the hole 2 and the light emitting element formed on the main surface 1 a of the insulating base 1, an external electrode terminal 5 formed on the other main surface 1 b of the insulating base 1, a connection terminal 3 and an external electrode terminal 5 The insulating base 1 is inserted into the through-hole 7 provided through the insulating base 1 so as to be electrically connected to the through-hole 2 provided through the insulating base 1 and joined to the insulating base 1. It is comprised from the metal body 8 with higher heat conductivity. A mounting portion 9 for mounting a light emitting element is formed between one connection terminal 3a and the other connection terminal 3b. The mounting portion 9 is preferably formed on the end surface of the metal body 8 from the viewpoint of heat dissipation.

  And in order to join the insulating base | substrate 1 and the metal body 8, the metal joining material 10 is formed between both.

  In the light emitting element wiring substrate 11 of the present invention, the bonding material 10 is formed, for example, as shown in FIG. 2A, above and below the bonding surfaces 8a and 12a, or as shown in FIG. 2B or 2C. It is important to intervene in the vicinity of one of the upper and lower joint surfaces 8a, 12a of the joint surfaces 8a, 12a.

In the present invention, the insulating base 1 and the metal body 8 are provided with steps that mesh with each other so as to overlap each other, and the joint surface where each step overlaps , the inner wall of the through-hole 2 in the vicinity of the joint surface , and the metal body in the side surface, by bonding the insulating substrate 1 and the metal body 8, it can be maintained by securing a sufficient junction area, as well as significantly reduce the width W of overlap step, a sufficient sealing property .

  That is, when the metal body 8 and the insulating base 1 are bonded together on the entire side surfaces, the stress is most concentrated on the corner 8b of the metal body 8 exposed on the surface of the metal body 8. By maintaining the free state without connecting and fixing the corners b of the 8 to the insulating base 1, it is possible to avoid cracking or peeling between the insulating base 1 and the metal body 8. When the depth at which the bonding material 10 does not intervene is smaller than 0.05 mm from the substrate surface, the bonding material 10 easily protrudes from the surface of the insulating base 1 or the metal body surface, thereby enabling the light emitting element to be mounted horizontally. There is a possibility that desired light emission characteristics cannot be obtained. Preferably, it is 0.1 mm or more, particularly 0.15 mm or more.

  In addition to the bonding surfaces 8a and 12a where the steps of the insulating substrate 1 and the metal body 8 face each other, the bonding area is expanded by utilizing the vicinity of the steps, and sufficient bonding reliability is ensured while the light emitting device is used. This makes it possible to reduce the size of the wiring board 11.

  In addition, even when the bonding material 10 is formed only in the vicinity of one of the stepped portions that become the bonding surface as shown in FIG. 2B or 2C, sufficient bonding reliability can be ensured. In particular, it is desirable to interpose the bonding material 10 on the side walls near the top and bottom of the step in order to balance the stresses above and below the step and suppress the warpage of the wiring board 11 for the light emitting element.

  Further, the width W of the joint surface where the step of the insulating substrate 1 and the step of the metal body 8 overlap is preferably less than 1 mm from the viewpoint of miniaturization. According to the light emitting element wiring substrate 11 of the present invention, even if the width W where the step of the insulating substrate 1 and the step of the metal body 8 overlap, which has been difficult in the past, is less than 1 mm, sufficient sealing is achieved. The stopping property can be maintained. The width W is preferably 0.8 mm or less, and more preferably 0.6 mm or less. Moreover, it is desirable to set it as 0.1 mm or more, especially 0.2 mm or more.

The insulating base 1 and the metal body 8 are joined by a brazing material made of metal. In order to sufficiently join the insulating base 1 made of ceramic and the joining material 10, the insulating base in which the joining material 10 is interposed. It is desirable that a metal layer 12 formed by simultaneous sintering with the insulating substrate 1 is formed on the inner wall of one through hole 2 . Since the bonding surface 12a of the metal layer 12 is easily wetted with the bonding material 10, the metal layer 12 formed on the insulating base 1 and the metal body 8 can be easily bonded to the bonding material 10.

  The metal layer 12 is formed by, for example, applying a metal paste to the through hole side wall of the ceramic green sheet before sintering to form the insulating substrate 1 by screen printing, or dispersing metal powder only on the inner wall portion of the through hole. It can also be formed by placing a metal sheet and laminating other insulating layers and then firing. Alternatively, the metal layer 12 may be formed by a heat treatment such as baking onto an insulating substrate after firing. In particular, when the metal layer 12 and the insulating substrate 1 are fired simultaneously, in other words, when the metal layer 12 is formed of sintered metal, the metal layer 12 and the insulating substrate 1 are not only firmly bonded. The light emitting element wiring substrate 11 can also be easily manufactured at low cost.

Further, as shown in FIGS. 3A and 3B, the distance between the metal body 8 and the insulating base 1 is directed toward the outer periphery of the through hole 2 at the joint surface of the step portion formed in the through hole 2 and the metal body 8. not good is possible to change Te. In other words, the formation of the reservoir portion of the bonding material 10 not only can suppress the outflow and protrusion of the bonding material 10 to the substrate surface, but also the stress generated by the bonding material 10 between the insulating base 1 and the metal body 8. Therefore, bonding reliability is improved. In order to change the distance from the metal body in a plane substantially parallel to the main surface of the insulating base 1, a predetermined shape is formed in the precursor of the insulating base 1 before firing by drilling, embossing or etching in advance. By forming the film, it is possible to obtain the same shape even after the insulating substrate 1 is heat-treated. Conversely, the metal body 8 can be processed to form a desired shape.

  In addition, as shown in FIG.3 (c), in the joint surface of the level | step-difference part formed in the through-hole 2 and the metal body 8, a joint surface inclines toward the outer peripheral direction of the through-hole 2 in an insulating base | substrate. Thus, the distance between the joint surface 8a of the metal body 8 and the joint surface 12a of the metal layer 12 can be changed in the outer peripheral direction. As a result, by forming the reservoir portion of the bonding material 10, not only can the outflow and protrusion of the bonding material 10 to the substrate surface be suppressed, but the bonding material 10 is generated between the insulating base 1 and the metal body 8. Since the stress is relieved, the bonding reliability is increased.

  In addition, as a method for inclining the bonding surface 12a of the insulating substrate 1, a high pressure / temperature is applied when the green sheets having through holes having different hole diameters are laminated and thermocompression bonded, in addition to the above-described embossing. By laminating and stacking, an inclined joint surface can be formed toward the outer periphery of the through hole. FIG. 3 (c) shows an example of a cross-sectional shape when the joint surface distance increases toward the outer periphery of the through hole. In addition, by reducing the distance between the joint surfaces toward the outer peripheral direction. Similar effects can be obtained. 3A, 3B, and 3C illustrate the case where the insulating substrate is processed, the metal body 8 may be formed in the same shape.

  Further, as shown in FIG. 3C, it is desirable that the distance C2 between the side wall surface of the through hole 2 and the side wall surface of the metal body 8 above and below the step of the through hole 2 is 0.3 mm or less. When the distance between the two is larger than 0.3 mm, the movement of the bonding material 10 between the through hole 2 and the metal body 8 may be insufficient on the wall surface substantially parallel to the penetration direction. There is a case where the bonding material 10 is not formed, and there is a fear that the characteristic variation becomes large. In addition, the distance C2 is particularly preferable from the viewpoint of assembly property and filling property of the bonding material 10, in other words, flowability of the bonding material 10 due to capillary force generated in the gap between the side wall of the metal body 8 and the metal layer 12 formed on the insulating base. 0.1 to 0.2 mm is desirable.

  As described above, by joining the insulating base and the metal body only at the joint surface where each step overlaps, the inner wall of the penetration in the vicinity of the joint surface and the side wall of the metal body, the width at which the step overlaps is increased. While making it remarkably small, sufficient sealing performance can be maintained.

  And as for the metal body 8 inserted and fixed to the through-hole 2, the maximum dimension in a surface perpendicular | vertical to a penetration direction is 1-3 mm, and the maximum dimension of a penetration direction is 0.15-0.6 mm. desirable. That is, by inserting and fixing the metal body 8 having a maximum dimension of 1 to 3 mm in the surface perpendicular to the penetration direction into the through hole 2, while promoting the miniaturization of the light emitting element wiring substrate 11, It becomes possible to quickly dissipate the heat generation, and in the present invention, the metal body 8 has a plate shape or a flat shape whose maximum dimension in the penetration direction is 0.15 to 0.6 mm, and easily deforms, Due to the difference in thermal expansion between the insulating substrate 1 and the metal body 8, it is particularly desirable to have a shape that can relieve the stress generated between them.

  Further, it is desirable that the maximum dimension in the plane perpendicular to the penetrating direction of the metal body 8 is 1 mm or more, and if it is less than 1 mm, heat generated from the light emitting element cannot be sufficiently dissipated, resulting in a decrease in luminance. On the other hand, if it is larger than 3 mm, it is difficult to reduce the size of the wiring board 11 for the light emitting element. Preferably, 1.5 mm or more is desirable, and 2-3 mm is most desirable. With this size, heat generated from the light emitting element can be dissipated well in the horizontal direction. The maximum dimension of the metal body 8 in the penetration direction is preferably 0.15 mm or more. When the metal body 8 is thinner than 0.15 mm, it becomes a foil shape, and thus tears and breaks occur during handling, making it difficult to handle the metal body 8. Further, when the thickness is greater than 0.6 mm, the rigidity of the metal body 8 is increased and the metal body 8 is less likely to be deformed. Therefore, due to the difference in thermal expansion between the insulating base 1 and the metal body 8 during brazing, Cracks and the like are easily generated in the insulating substrate 1 due to the generated stress, and the reliability is lowered. Preferably, 0.4 mm or less is desirable, and 0.15 to 0.3 mm is most desirable. With this size, the heat from the light emitting element is quickly dissipated and at the same time easily deformed to relieve the stress generated between the insulating base 1 and the metal body 8 due to the difference in thermal expansion. It is desirable.

  In addition, when providing a level | step difference in the side surface of the metal body 8, the magnitude | size of the one end surface of the metal body 8 and the other end surface does not need to be different like FIG. For example, even if the size of one end surface of the metal body 8 is the same as that of the other end surface, the side surface of the metal body 8 can be provided with irregularities in a range that does not hinder the insertion of the metal body 8. Needless to say.

  In addition, as shown in FIG. 1, by making one end surface of the metal body 8 larger than the other end surface, positioning when inserting the metal body 8 into the through hole 2 is facilitated. There is also an advantage of improving.

  Furthermore, by increasing the area of the end face of the metal body 8 on the side opposite to the mounting portion 9, the heat transfer path becomes wider and the heat dissipation of the light emitting element wiring board is further improved. In particular, it is desirable that one end surface of the metal body 8 has an area that is 1.1 times or more that of the other end surface, and more preferably 1.2 times or more.

  In this way, by providing the metal body 8 that is small and has a higher thermal conductivity than the insulating base 1, heat generated from the light emitting element mounted on the wiring board for light emitting element of the present invention can be quickly dissipated. Therefore, it is possible to prevent a decrease in luminance of the light emitting element.

  Such a metal body 8 can be easily obtained by punching a metal plate made of Cu or Al, which has high thermal conductivity, low resistance, and relatively inexpensive, or a metal foil into a desired shape using a press or the like. Can be produced.

  The metal body 8 having a complicated shape can be formed by a technique such as pressing, casting, polishing, powder metallurgy, or the like. Needless to say, the metal body 8 may be manufactured by using other conventionally known processing methods.

  Moreover, as a raw material of the metal plate 8, in addition to Cu and Al, a composite material such as Ag or Cu-W can be used. In the case of using a composite material such as Cu-W containing two or more kinds of metals, the metal body 8 having desired characteristics can be produced by controlling the metal used and its ratio. Of course, the metal body 8 may be made of an alloy. Moreover, the metal body 8 may be configured by combining a plurality of members.

  In addition, it is desirable that the metal body 8 has substantially the same thickness as the insulating base 1 in order to flatten the mounting portion 9 of the light emitting element.

  Such a metal body 8 can be easily obtained at low cost and can be easily attached to various forms of the insulating base 1, so that various forms of the insulating base can be used according to the performance of the mounted light emitting element. 1 can be used to achieve an optimal combination based on performance and cost.

Next, the insulating base 1 will be described. As the insulating base 1 used for the light emitting element wiring substrate 11, for example, a ceramic substrate such as MgO or Al ₂ O ₃ can be suitably used.

  When a ceramic substrate is used as the insulating substrate 1, it has high performance because it is highly rigid, does not change in quality due to light or heat emitted from the light emitting element, and has a relatively large number of materials with relatively high thermal conductivity. The light-emitting element wiring substrate 11 has a long life.

In addition, when a low-temperature fired substrate, so-called glass ceramics, is used as the insulating substrate 1, the thermal conductivity, strength, and rigidity are not limited to ceramics fired in a temperature range of 1050 ° C. or higher such as Al ₂ O _3. Although it is inferior, since the thermal expansion coefficient can be easily controlled, it is possible to easily match the thermal expansion coefficient with the metal body 8. Further, since low resistance Cu, Ag, or the like can be simultaneously fired as the wiring layer, electrical loss and heat generation in portions other than the light emitting element can be suppressed.

  The materials used as these insulating bases 1 will be described in detail below.

For example, when an Al ₂ O ₃ sintered body having Al ₂ O ₃ as a main crystal phase is used as the insulating substrate 1, an inexpensive raw material can be used, and an inexpensive wiring board 11 for a light emitting element can be obtained. Can do.

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

Such an Al ₂ O ₃ sintered body has, for example, an average particle size of 0.1 to 8 μm, preferably 1.0 to 2.0 μm and an Al ₂ O ₃ powder with a purity of 99% or more and an average particle size of 1 Firing a molded body to which at least one kind of sintering aid selected from the group of Mn ₂ O ₃ , SiO ₂ , MgO, SrO and CaO of 0 to 2.0 μm is added in a temperature range of 1300 to 1600 ° C. Is obtained.

And, for the addition amount of Al ₂ O ₃ other than the compositions, such as sintering aids, in order to obtain a dense body of the Al ₂ O ₃ as a main crystal, preferably 15 wt% or less, more desirably, 10 It is desirable to set it as mass% or less. In particular, when the amount of a composition other than Al ₂ O ₃ such as a sintering aid is set to 15% by mass or less, most of the obtained insulating substrate 1 can be formed of Al ₂ O ₃ crystals. . These sintering aids are desirably added in an amount of 5% by mass or more, and more preferably 7% by mass or more in order to lower the firing temperature. Note that as the ceramic used for the insulating substrate 1, a sintered body having AlN, Si ₃ N ₄ or the like as a main crystal may be used.

To such a composition containing MgO or Al ₂ O ₃ as a main component, a binder and a solvent are further added to prepare a slurry. For example, a sheet-like molded body is prepared by a doctor blade method, Then, after printing and filling a conductive paste containing at least a metal powder on the surface or through holes provided in the sheet-like molded body, the sheet is laminated and then laminated in an oxidizing atmosphere, a reducing atmosphere, or an inert atmosphere. By firing, the insulating base body 1 in which wiring layers such as the connection terminals 3, the external electrode terminals 5, and the through conductors 7 are formed on the surface or inside can be manufactured. Needless to say, the wiring layer can be formed on the surface of the insulating substrate 1 by a thin film method or by transferring a metal foil onto the surface of the molded body.

  Needless to say, it is necessary to previously form a hole to be the through hole 2 for inserting the metal body 8 in the sheet-like molded body before the firing step.

  Further, even when a low-temperature fired substrate is used as the insulating substrate 1, the insulating substrate 1 provided with the through-holes 2 and the wiring layer is basically manufactured in the same manner, although the materials and the firing temperature are different. Can do.

  Next, a metal body 8 made of Cu is prepared for the various insulating bases 1 provided with the through holes 2 described above, the metal body 8 is inserted into the through holes 2, and a bonding material 10 made of metal. Thus, the insulating substrate 1 and the metal body 8 can be joined together to obtain the light emitting element wiring substrate 11.

  Further, by applying Al plating or Ag plating to the surfaces of the connection terminal 3 and the metal body 8, the resistance to corrosion is improved, the reliability of the wiring board 11 for the light emitting element is improved, and the connection terminal 3 and the metal body are improved. The reflectance of 8 can be improved.

  A frame body can be provided on the main surface of the light emitting element wiring substrate 11 on the mounting portion 9 side. For example, when the insulating substrate 1 made of ceramics is used, the frame body is made of ceramics. By forming, the insulating base 1 and the frame can be fired at the same time, and the process is simplified, so that the inexpensive light emitting element wiring substrate 11 can be easily manufactured.

  Further, by forming the frame body with a metal that is inexpensive and excellent in workability, even a frame body having a complicated shape can be easily manufactured at low cost, and the inexpensive light-emitting element wiring substrate 11 can be manufactured. Can be supplied. The metal frame can be suitably formed from, for example, Al or Fe—Ni—Co alloy. Further, a plating layer made of Ni, Au, Ag, Al, or the like may be formed on the inner wall surface of the frame in order to improve the reflectance.

  When the frame is formed of a metal as described above, brazing via a brazing material made of a eutectic Ag—Cu brazing material or the like, or joining by soldering can be performed.

  Needless to say, a resin-based adhesive may be used, and it is desirable to use a generally used epoxy resin-based adhesive as the material.

  Then, for example, as shown in FIG. 4A, the LED chip 21 or the like is mounted as the light emitting element 21 on the wiring board 11 for the light emitting element of the present invention described above, and is connected to the light emitting element 21 by the bonding wire 23. By electrically connecting the terminal 3 and supplying power to the light emitting element 21, the light emitting element 21 can function and heat generated from the light emitting element 21 can be quickly emitted from the metal body 8. Thus, a heat emitting member such as the above can be dispensed with, which contributes to the downsizing of the electric equipment to be mounted. In addition, by providing a heat sink, it is needless to say that heat dissipation is further improved, and for example, provision of a cooling device such as a heat sink is not excluded.

  Further, an LED chip 21 or the like is mounted on the mounting portion 9 formed on the light emitting element wiring substrate 11 as, for example, the light emitting element 21, and the LED chip 21 and the connection terminal 3 are electrically connected by the bonding wire 23. By supplying power, the light emitted from the light emitting element 21 can be reflected by the insulating substrate 1 and the frame and guided in a predetermined direction, so that the highly efficient light emitting device 25 is obtained. In addition, since the metal body 8 has a high thermal conductivity, heat generated from the light emitting element 21 can be quickly released, and a reduction in luminance due to heat generation can be suppressed.

  In the example shown in FIG. 4A, the light emitting element 21 is fixed to the light emitting element wiring substrate 11 with an adhesive 29, and power is supplied by the wire bond 23. Needless to say, the connection form with the terminal 11 may be flip-chip connection.

  Moreover, although the light emitting element 21 is covered with the molding material 31, it may be sealed using a lid (not shown) without using the molding material 31, or the molding material 31 and the lid. And may be used in combination. In addition, as a cover body, it is desirable to use translucent materials, such as glass.

  In addition, when mounting the light emitting element 21, you may add the fluorescent substance (not shown) for wavelength-converting the light which the light emitting element 21 radiates | emits to this molding material 31 as needed.

  In the example described above, the example in which the through conductor 7 is provided has been described. However, the through conductor 7 may not be provided, and the insulating base 1 may be laminated in multiple layers. Of course it is good.

  Moreover, in the example demonstrated above, although all demonstrated the form which does not comprise a frame, it cannot be overemphasized that the form which provided the frame may be sufficient.

Al ₂ O ₃ powder having a purity of 99% or more and an average particle size of 1.0 μm as a raw material powder, Mn ₂ O ₃ powder having a purity of 99% or more and an average particle size of 1.3 μm, a purity of 99% or more, an average particle size of 1. using SiO ₂ powder 0 .mu.m, _Al 2 _{O 3} powder 90 wt%, _Mn 2 _{O 3} powder 5% by weight, mixing the raw material powder at a ratio of SiO ₂ powder 5% by weight, as molding organic resin (binder) An acrylic binder and toluene were mixed as a solvent to prepare a slurry. Thereafter, a ceramic green sheet was prepared by a doctor blade method.

In addition, using W and Cu powder with an average particle diameter of ₂ μm and Al ₂ O ₃ with an average particle diameter of 1.0 μm, W 80 mass%, Cu 20 mass%, and Al ₂ O ₃ 5 mass% in proportions of metal powder and acrylic Binder and acetone were mixed as a solvent to prepare a conductor paste. The above ceramic green sheet was punched to form a via hole with a diameter of 100 μm for forming a through conductor. In addition, the conductor paste was filled by a screen printing method and printed and applied in the form of a wiring pattern. In addition, a through hole for inserting a metal body was formed together with a via hole during punching.

  Further, a conductive paste is applied to the punched surface or the bonding surface of the green sheet that becomes the inner wall surface of the through hole by screen printing so that the bonding material interposed between the inner wall of the through hole and the side wall of the metal body is firmly bonded to the insulating substrate. Printed.

  Two green sheets having a thickness of 0.3 mm after firing thus prepared are aligned, laminated and pressure-bonded, and a laminate having dimensions after firing of 5 mm × 5 mm × 0.6 mm in thickness is produced. did. In addition, this laminated body does not provide a frame.

  In addition, the sample in which the distance between the bonding surface of the insulating substrate and the bonding surface of the metal body inside the through-hole becomes small is used to form a portion that becomes the bonding surface before lamination of the green sheet as a convex portion using a mold. The height difference from the recess was set to 50 μm.

  In addition, with respect to the bonding material interposed between the through hole and the metal body, when the bonding material is interposed only in the bonding surface of the stepped portion, and when the bonding material is interposed in the vicinity of either the upper or lower bonding surface of the bonding surface When preparing a sample in the case where the bonding material is present both above and below the bonding surface, a sample in which the bonding material using solder is interposed up to the substrate surface and when the bonding material is interposed only in the vicinity of the bonding surface including the bonding surface In order to produce, the dimension of the metal layer formed in the inner wall of the through hole was changed as shown in Table 1.

  In the following, as shown in the schematic diagram of FIG. 6, the diameter of the end surface of the columnar metal body 8 provided with a step is set to 2 mm, which is the smaller diameter, and is denoted by L1, and the diameter of the opposite end surface is 3 mm, L2. The depth of the region where the bonding material above the bonding surface is not formed is D1, the depth of the region where the bonding material below the bonding surface is not formed is D2, the distance between the bonding surfaces is C1, and the bonding surfaces are Let W be the width of the overlap, and C2 be the distance between the metal body and the insulating substrate.

  And after degreasing at 900 degreeC in nitrogen-hydrogen mixed atmosphere with dew point +25 degreeC, it hold | maintained at 1300 degree C for 2 hours in nitrogen-hydrogen mixed atmosphere with dew point +25 degreeC continuously, and baked.

  Thereafter, Ni and Au plating were sequentially applied to the surfaces of the connection terminal and the external electrode terminal.

An epoxy resin as an adhesive is applied to these light emitting element wiring boards using a dispenser, an LED chip which is a light emitting element with an output of 1.5 W is mounted on the mounting portion, and the LED chip and the connection terminal are connected by a bonding wire. Further, the LED chip and the connection terminal were covered with a molding material made of an epoxy resin having a thermal expansion coefficient of 40 × 10 ⁻⁶ / ° C., to obtain a light emitting device.

  The obtained light-emitting device was subjected to a temperature cycle test of −55 ° C. to 125 ° C. for 1000 cycles, and after the test, the peeling state of the bonding interface between the metal body and the insulating substrate was confirmed.

  Further, a current of 0.4 A was passed through the light emitting device, and the total radiant flux was measured after 1 hour.

Table 1 shows the characteristics and test results of the light-emitting element wiring substrate manufactured through the above steps.

  As shown in Table 1, the sample No. which is outside the scope of the present invention having no step. In Nos. 1 and 2, peeling of the bonding material was observed at the joint between the metal body and the insulating substrate after the temperature cycle test. In addition, Sample No. in which no bonding material is formed in any of the upper and lower regions of the bonding surface. In No. 15, the bonding area was not sufficiently ensured, and peeling of the bonding material was observed at the bonding portion between the metal body and the insulating substrate. In addition, Sample No. having a bonding material in all regions between the metal body and the insulating substrate. No. 19 also showed peeling of the bonding material, and it was confirmed that the bonding material oozed out from the front and back surfaces of the substrate.

On the other hand, the sample is a wiring substrate for emitting light element No. 3-14, and In Nos. 16 to 18, peeling was not confirmed between the metal body and the insulating substrate, and the wiring boards for light-emitting elements having excellent bonding reliability, heat dissipation, and optical characteristics were obtained. Here, Sample No. 17 is a sample of the present invention. Reference numerals 3 to 14, 16 and 18 are reference materials.

  In particular, even if the overlapping width of the joining surfaces is less than 1 mm, no peeling is confirmed, and therefore the present invention can be easily downsized.

(A) is sectional drawing of the wiring board for light emitting elements of this invention which provided the joining surface and the bonding material on the upper side, (b) is the bonding surface and the lower side of the present invention which provided the bonding material on the lower side. It is sectional drawing of the wiring board for light emitting elements. (A) is the principal part enlarged view of the wiring board for light emitting elements of this invention which provided the joining surface and the bonding material on the upper and lower sides, (b) is this invention which provided the bonding material on the bonding surface and its upper side. FIG. 2C is an enlarged view of a main part of a light emitting element wiring board of the present invention in which a bonding material and a bonding material are provided below the bonding surface. (A), (b) is the principal part enlarged view of the wiring board for light emitting elements of this invention which provided the unevenness | corrugation in the joint surface of the insulation base, (c) provided the inclination in the joint surface of the insulation base. It is a principal part enlarged view of the wiring board for light emitting elements of this invention. It is sectional drawing of the light-emitting device of this invention. It is sectional drawing explaining the shape of the wiring board for light emitting elements in the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Insulation base | substrate 2 ... Through-hole 3 ... Connection terminal 5 ... External electrode terminal 7 ... Through-conductor 8 ... Metal body 8a ... Metal body joint surface 8b ... Metal body Corner portion 9... Mounting portion 10 .. bonding material 11 .. wiring board 12 for light emitting element .. metal layer 12 a. Bonding surface 21 of metal layer .. light emitting element 25.

Claims (5)

A conductor layer is formed on at least one of the surface and the inside of a flat ceramic substrate, and a metal body is inserted into a through-hole penetrating between the main surfaces of the insulating substrate. a wiring substrate for light-emitting element and the metal body is joined, the inner wall of the through hole having a stepped Rutotomoni, the side surface of the metal body, the step a step that mates to overlap vertically provided cage, at least one of the lower side of the upper and the joint surface from the bonding surface of the through hole of the step and the metal body step of vertically mutually opposite each other joint surfaces and between the through-hole of the prior SL through hole and characterized in that the inner wall and the metal body, wherein are joined only in the vicinity of the joint surface, and the distance of the joining surfaces facing each other is changed toward the outer circumferential direction of the through-hole Wiring board that the light emitting element. The light-emitting element wiring board according to claim 1, wherein a metal layer for bonding to which the bonding material is bonded is arranged on the insulating base. The light-emitting element wiring board according to claim 1, wherein the metal layer is a sintered metal body embedded in the insulating base.   The light-emitting element wiring board according to claim 1, wherein a width of the bonding surface is less than 1 mm. The light emitting device characterized by comprising by mounting the light emitting element to the light emitting element wiring board according to any one of claims 1 to 4.

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