JP2009260179A - Package for storing light-emitting element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a package for storing a light-emitting element, capable of efficiently dissipating heat from the light-emitting element. <P>SOLUTION: In the package 10 for storing the light-emitting element, the light-emitting element 12 is mounted on the upper surface of an insulating substrate 11. The insulating substrate 11 includes ceramics that are baked together with a high melting-point metal such as tungsten and molybdenum simultaneously in the reducing atmosphere at a high temperature exceeding 1,530°C. A portion of the insulating substrate 11 where the light-emitting element 12 is mounted includes thermal vias 13, 13a, and 13b consisting of copper plated coats 16, 16a, and 16b provided to a metallized film 15 of high melting-point metal on a wall surface of a through-hole 14 formed in the insulating substrate 11. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a light emitting element storage package for storing light emitting elements such as a plurality of LEDs (Light Emitting Diodes), and more particularly, a light emitting element storage for efficiently dissipating heat from the light emitting elements. For packages.

  Conventionally, a light emitting element is supported by increasing an input current as one of means for improving illuminance. However, although the illuminance of the light emitting element is increased by increasing the input current, the light emitting element is heated to generate a large amount of heat. Along with this heat generation, the light emitting element has a problem that the illuminance is decreased.

With reference to FIGS. 3A and 3B, a conventional light emitting element storage package will be described. Here, FIGS. 3A and 3B are an explanatory view of a conventional light emitting element storage package and an enlarged explanatory view of a thermal via, respectively.
As shown in FIG. 3A, in the conventional light emitting element storage package 50, in order to mount the light emitting element 51, the insulating base 52 is made of ceramic or resin. However, since the resin has a lower thermal conductivity and inferior heat dissipation than ceramic, it is not suitable for the light emitting element storage package 50 that requires special heat dissipation. Therefore, in such a case, the insulating base 52 is provided with a resin substrate (thermal conductivity: 0.19 W / m ··) having a thermal conductivity of a resin, for example, a BT resin (a resin containing bismaleimide triazine as a main component). High alumina (Al ₂ O ₃ ) (thermal conductivity: about 17.8 W / m · K), aluminum nitride (AlN) (thermal conductivity: about 120 W / m · K), etc. More and more ceramic is used. However, when aluminum nitride is used for the insulating base 52 of the light emitting element housing package 50, the cost of the light emitting element housing package 50 is increased because aluminum nitride is expensive.

  When alumina ceramic is used for the light emitting element storage package 50, first, a plurality of ceramic green sheets made of alumina are produced. Each ceramic green sheet is screen-printed using a conductive paste made of a refractory metal such as tungsten (W) or molybdenum (Mo), and each ceramic green sheet is laminated and laminated. Insulating substrate 52 made of a ceramic multilayer substrate is formed by simultaneously firing high melting point metals at a high temperature. As a result, in the light emitting element storage package 50, the connection pads 53 for mounting the light emitting element 51 on the upper surface of the insulating base 52 by wire bonding or flip chip mounting are made of tungsten, molybdenum or the like. It is provided with a melting point metal. Further, in the light emitting element storage package 50, a frame-like reflector 54 made of ceramic, metal or the like is formed on the upper surface of the insulating base 52 so as to surround the light emitting element 51 and reflect light emitted from the light emitting element 51. Has been. Further, the light emitting element storage package 50 is electrically connected to the lower surface of the insulating substrate 52 via the connection pads 53 on the upper surface of the insulating substrate 52 and the conductor wiring pattern 55 provided inside the insulating substrate 52. The external connection terminal pad 56 is provided with a refractory metal such as tungsten or molybdenum.

  The light emitting element storage package 50 is provided with a heat sink plate 57 that is in contact with the insulating base 52, for example, aluminum or the like, in order to dissipate the heat generated from the light emitting element 51 downward. The light-emitting element storage package 50 has a wiring such as a board provided on the heat sink plate 57 in order to electrically connect the light-emitting element 51 to be mounted to the outside through the external connection terminal pad 56. External connection terminal pads 56 are joined to terminals of the substrate 58 with solder 59 or the like.

However, even if this light emitting element storage package 50 uses an insulating base 52 made of a ceramic multilayer substrate with excellent thermal conductivity and uses a heat sink plate 57 on the lower surface, in the case of a ceramic multilayer substrate made of alumina, in recent years. In an electronic device in which the improvement of the light emission efficiency is required, the thermal conductivity for efficiently radiating the heat generated from the increasing light emitting element 51 is small, and the decrease in the illuminance of the light emitting element 51 due to heat can be suppressed. I can't. Therefore, as shown in FIG. 3B, the light emitting element storage package 50 includes tungsten or molybdenum in a through hole 60 provided in a ceramic green sheet on which the light emitting element 51 of the insulating base 52 made of alumina is mounted. A thermal via 62 in which a high-melting point metal such as is filled and simultaneously fired to fill the through hole 60 with a via conductor 61 made of a high-melting point metal is provided. The light emitting element storage package 50 transfers heat generated from the light emitting element 51 to the lower heat sink plate 57 through the thermal via 62 and dissipates the heat from the heat sink plate 57 to the outside. However, the thermal via 62 made of the via conductor 61 filled with a high melting point metal such as tungsten or molybdenum has a low thermal conductivity of about 35 W / m · K such as tungsten or molybdenum. The heat transfer is low, the heat radiation cannot be efficiently performed, and the effect of reducing the thermal resistance θ _j-c of the light emitting element 51 is low. Moreover, in order to approximate the thermal expansion coefficient of each refractory metal such as tungsten and molybdenum co-fired with ceramic as much as possible to the thermal expansion coefficient of the ceramic as much as possible, A refractory metal containing the same ceramic powder is used. As a result, via conductor 61 made of refractory metal such as tungsten or molybdenum fired by containing ceramic powder has a thermal conductivity of 35 W / in contrast to the case of single metal tungsten or refractory metal such as molybdenum. Thus, the effect of reducing the thermal resistance θ _j-c of the light emitting element 51 is further reduced.

A conventional ceramic wiring board that can also be used for a package for storing light emitting elements has copper powder, an organic vehicle, and ceramic particles in a through hole of a ceramic green sheet for low temperature firing that can be fired at a relatively low temperature. There has been proposed a wiring board in which a thermal via is provided by filling the contained copper paste and simultaneously firing ceramic and metal at about 1000 ° C. (see, for example, Patent Document 1).
Further, a conventional ceramic wiring board that can also be used for a light emitting element storage package is filled with a paste containing copper and tungsten and / or molybdenum in a through hole of a ceramic green sheet. A wiring board provided with thermal vias by simultaneously firing ceramic and metal in a non-oxidizing atmosphere at ˜1500 ° C. has been proposed (see, for example, Patent Document 2).
Furthermore, a conventional ceramic wiring substrate that can be used for a light emitting element storage package can be fired at a relatively low temperature, and the ceramic green sheet made of glass ceramic has a through hole of 85% by volume or more of copper. There has been proposed a wiring board in which a paste formed therein is filled and ceramic and metal are simultaneously fired at about 900 ° C. to provide a thermal via (see, for example, Patent Document 3).

JP 2004-134378 A JP 2000-164992 A JP 2004-228410 A

However, the conventional light emitting element storage package as described above has the following problems.
(1) A light emitting element storage package using a wiring board as disclosed in Japanese Patent Application Laid-Open No. 2004-134378 has a high thermal conductivity in which thermal vias formed by filling and baking copper paste have high thermal conductivity. The ceramic is made of a so-called low-temperature fired ceramic that is fired at a relatively low temperature of about 1000 ° C., the ceramic has low thermal conductivity, the thermal conductivity of the entire package is lowered, and the heat generated from the light emitting element Cannot be radiated efficiently.
(2) A light emitting element storage package using a wiring board as disclosed in Japanese Patent Application Laid-Open No. 2000-164992 is formed by filling a conductor paste in which copper and tungsten and / or molybdenum are mixed and firing. Even if the thermal vias made have a higher thermal conductivity than the conductor when only tungsten and / or molybdenum and the ceramic fired at 1200-1500 ° C. has a higher thermal conductivity than does the low temperature fired ceramic, Since the thermal conductivity is lower than in the case of copper alone or high-temperature fired ceramic, the thermal conductivity of the entire package is low, and heat generated from the light emitting element cannot be efficiently radiated.
(3) In the light emitting element storage package using the wiring board as disclosed in Japanese Patent Application Laid-Open No. 2004-228410, the thermal via is formed of copper as in the case of Japanese Patent Application Laid-Open No. 2004-134378. However, since the ceramic is made of glass ceramic and has low thermal conductivity, the thermal conductivity of the entire package is low, and heat generated from the light emitting element cannot be efficiently radiated.

  This invention is made | formed in view of this situation, Comprising: It aims at providing the package for light emitting element accommodation which can thermally radiate the heat_generation | fever from a light emitting element efficiently.

  The light-emitting element storage package according to the present invention that meets the above-described object is a light-emitting element storage package in which a light-emitting element is mounted on the upper surface of an insulating substrate. It is made of a ceramic that can be fired simultaneously in a high-temperature reducing atmosphere, and is provided on a metallized film of a refractory metal provided on a wall surface of a through hole formed in the insulating substrate at a portion where the light emitting element of the insulating substrate is mounted. It has a thermal via made of a copper plating film.

  Here, the light emitting element storage package transfers heat generated from the light emitting element to the lower surface of the insulating base through the insulating base and the copper plating film of the thermal via, and the insulating base and the thermal via. It is preferable to have a heat sink plate that is directly connected to the copper plating film to dissipate heat.

The light-emitting element storage package according to claim 1 or claim 2 dependent thereon is made of an insulating substrate made of a refractory metal such as tungsten or molybdenum and a ceramic that can be co-fired in a reducing atmosphere at a high temperature exceeding 1530 ° C. Since the thermal via made of a copper plating film provided on the metallized film of the refractory metal provided on the wall surface of the through-hole formed in the insulating substrate is provided at the site where the light emitting element of the insulating substrate is mounted, The ceramic to be fired has a relatively high thermal conductivity, and the thermal vias of the copper plating film have a high thermal conductivity. through the thermal via is conducted to the lower part of effectively insulating base can be radiated, the illuminance of the light emitting device to enhance the effect of reducing the thermal resistance theta _j-c of the light emitting element It is possible to improve.

In particular, the light-emitting element storage package according to claim 2 transfers heat from the light-emitting element downward to the lower surface of the insulating base via the insulating base and the copper plating film of the thermal via, and also includes the insulating base and the thermal base. Since it has a heat sink plate that directly connects to the copper plating film of the via and dissipates heat, the ceramics with relatively high thermal conductivity and the heat sink plate that the copper plating film of high thermal conductivity thermal connection directly connects to the light emitting element. The generated heat can be quickly transferred to the heat sink plate and can be dissipated from the heat sink plate, so that the effect of reducing the thermal resistance θ _j-c of the light emitting element can be enhanced and the illuminance of the light emitting element can be improved.

Subsequently, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention.
1A and 1B are explanatory diagrams of a light emitting element storage package according to an embodiment of the present invention, enlarged explanatory diagrams of thermal vias, and FIGS. 2A and 2B are respectively. It is the expansion explanatory view of the modification of the thermal via of the package for light emitting element accommodation, and the expansion explanatory view of another modification.

With reference to FIGS. 1A and 1B, a light-emitting element storage package according to an embodiment of the present invention will be described.
As shown in FIG. 1A, the shape of the light emitting element storage package 10 according to the embodiment of the present invention is not limited. For example, an LED or the like is formed on the upper surface of a rectangular insulating substrate 11. The light emitting element 12 is mounted. The light emitting element storage package 10 may be made of alumina or ceramic such as aluminum nitride that is fired at a high temperature on the insulating substrate 11. In order to form the insulating substrate 11 from this ceramic, first, a sintering aid, a plasticizer, a binder, and a solvent are added to ceramic powder such as alumina or aluminum nitride, and the mixture is thoroughly kneaded and defoamed. A slurry is prepared, and a sheet-like ceramic green sheet having a desired thickness is prepared by a doctor blade method or the like. Next, each ceramic green sheet is screen-printed using a conductive paste made of a refractory metal such as tungsten or molybdenum to form a conductor pattern, and the ceramic green sheets are stacked and laminated. A ceramic and a refractory metal are simultaneously fired at a high temperature in a non-oxidizing atmosphere to form an insulating substrate 11 made of a ceramic multilayer substrate. For example, when the ceramic is alumina, this co-firing is performed at a high temperature in a reducing atmosphere of refractory metal such as tungsten or molybdenum and hydrogen and nitrogen at about 1550 ° C. For example, when the ceramic is aluminum nitride, this co-firing is performed at a high temperature in a nitrogen atmosphere of about 1700 ° C. with a refractory metal such as tungsten or molybdenum.

  When the insulating substrate 11 is made of aluminum nitride, the light emitting element storage package 10 has a high thermal conductivity of about 120 W / m · K, and thus suppresses a decrease in light emission efficiency due to heat of the light emitting element that generates high heat. Therefore, it is a suitable material that can promote prompt heat dissipation, and heat generated from the light emitting element 12 can be quickly transferred downward to dissipate heat, and a thermal via 13 is provided at a site where the light emitting element 12 is mounted. The necessity is low. However, aluminum nitride is expensive and increases the cost of the light emitting element storage package 10.

  Therefore, the light emitting element storage package 10 uses an inexpensive ceramic made of alumina for the insulating substrate 11. When the insulating substrate 11 is made of alumina, its thermal conductivity is about 17.8 W / m · K, so that heat generated from the light emitting element 12 can be quickly transferred downward to dissipate heat. It is highly necessary to provide the thermal via 13 at the site where the light emitting element 12 is mounted. Therefore, the light emitting element storage package 10 in the case where the insulating base 11 is made of alumina has a high melting point such as tungsten or molybdenum on the wall surface of the through hole 14 formed in the insulating base 11 at the portion where the light emitting element 12 is mounted. A metallized film 15 made of metal is provided, and a thermal via 13 made of a copper plating film 16 is provided on the surface thereof. In the light emitting element storage package 10 provided with the thermal vias 13, the copper plating film 16 is made of copper as a pure metal, and its thermal conductivity is as high as about 390 W / m · K. It is possible to efficiently dissipate heat generated from the light emitting element by increasing the thermal conductivity of the entire package while covering the rate.

  The form of the thermal via 13 of the light emitting element storage package 10 described above is provided with a metallized film 15 made of a refractory metal such as tungsten or molybdenum on the wall surface of the through hole 14 formed in the insulating substrate 11. A copper plating film 16 is provided on the surface, and the thermal via 13 has a cavity. Further, in the form of the thermal via 13a as a modified example of the light emitting element storage package 10, as shown in FIG. 2A, a metallized film 15 is provided on the wall surface of the through hole 14 formed in the insulating base 11, and A copper plating film 16a is provided on the surface, and the metallized film 15 and the thermal via 13a that closes the through hole 14 with the copper plating film 16a and leaves the gap 17 inside the copper plating film 16a are used. There may be. Further, in the form of the thermal via 13b of another modification of the light emitting element storage package 10, as shown in FIG. 2B, a metallized film 15 is formed on the wall surface of the through hole 14 formed in the insulating base 11. Further, a copper plating film 16b is provided on the surface so as to close the through hole 14 with the metallized film 15 and the copper plating film 16b, and dents 18 are left at both ends of the copper plating film 16b. The thermal via 13b may be used.

  In the light emitting element storage package 10, the connection pad 19 for mounting the light emitting element 12 on the upper surface of the insulating substrate 11 by wire bonding or flip chip bonding is mounted on a refractory metal such as tungsten or molybdenum. Is provided. The light emitting element storage package 10 is provided with a frame-like reflector 20 made of ceramic, metal, or the like for reflecting the light emitted from the light emitting element 12 by surrounding the light emitting element 12 on the upper surface of the insulating substrate 11. It has been. Further, the light emitting element storage package 10 is electrically connected to the lower surface of the insulating substrate 11 via the connection pads 17 on the upper surface of the insulating substrate 11 and the conductor wiring pattern 21 provided inside the insulating substrate 11. The external connection terminal pad 22 is provided with a refractory metal such as tungsten or molybdenum. The external connection terminal pad 22 may be provided on the upper surface of the insulating substrate 11 in some cases.

  The light emitting element storage package 10 is in contact with the lower surface of the insulating base 11, and heat generated from the light emitting element 12 is transmitted through the insulating base 11 and the copper plating films 16, 16a, 16b of the thermal vias 13, 13a, 13b. The heat sink plate 23 is made of an aluminum plate or the like that is directly connected to the insulating base 11 and the copper plating films 16, 16 a, 16 b of the thermal vias 13, 13 a, 13 b to dissipate heat. The light emitting element storage package 10 has a wiring such as a board provided on the heat sink plate 23 in order to electrically connect the light emitting element 12 to be mounted to the outside through the external connection terminal pads 22. External connection terminal pads 22 are joined to terminals of the substrate 24 by solder 25 or the like. Although not shown, in the case of the light emitting element storage package 10 in which the external connection terminal pads 22 are formed on the upper surface of the insulating substrate 11, the entire lower surface of the insulating substrate 11 is applied to the planar upper surface of the heat sink plate 23. The heat dissipation from the heat sink plate 23 can be further improved.

The inventor provides a sample of an example of a package for a light-emitting element housing having a thermal via in which a metallized film made of tungsten is provided on a wall surface of a through hole provided in an insulating base made of alumina and a copper plating film is further provided on the surface thereof, About a sample of a conventional example of a light emitting element storage package having a thermal via in which a through hole provided in an insulating base made of alumina is filled with tungsten, and a sample of a comparative example of a light emitting element storage package not having a thermal via on an insulating base The thermal resistance θ _j-c was calculated by simulation using the finite element method, and the respective reduction effects were measured. The results are shown in Table 1 as a graph.

The sample of the conventional example was able to confirm a reduction effect of 15% of the thermal resistance θ _j-c compared to the sample of the comparative example, but the sample of the example further has a thermal resistance θ _{j of} 50% exceeding the sample of the comparative example. The reduction effect of _-c could be confirmed and proved to be large.

  The light emitting element storage package of the present invention is required to have high luminous efficiency, and can be used as a lamp for automobile headlamps or street lamps that generate a large amount of heat.

(A), (B) is explanatory drawing of the package for light emitting element accommodation which concerns on one embodiment of this invention, respectively, and is an expansion explanatory drawing of a thermal via. (A), (B) is the expansion explanatory drawing of the modification of the thermal via of the light emitting element storage package, respectively, and the expansion explanatory drawing of another modification. (A), (B) is explanatory drawing of the package for the conventional light emitting element accommodation, and the expansion explanatory drawing of a thermal via, respectively.

Explanation of symbols

  10: Light emitting element storage package, 11: Insulating substrate, 12: Light emitting element, 13, 13a, 13b: Thermal via, 14: Through hole, 15: Metallized film, 16, 16a, 16b: Copper plating film, 17: Void , 18: dent, 19: connection pad, 20: reflector, 21: conductor wiring pattern, 22: external connection terminal pad, 23: heat sink plate, 24: wiring board, 25: solder

Claims (2)

In the light emitting element storage package in which the light emitting element is mounted on the upper surface of the insulating substrate,
The insulating substrate is made of a refractory metal such as tungsten or molybdenum and a ceramic that can be fired simultaneously in a reducing atmosphere at a high temperature exceeding 1530 ° C., and the insulating substrate is mounted on a portion of the insulating substrate where the light emitting element is mounted. A package for accommodating a light emitting element, comprising a thermal via made of a copper plating film provided on the metallized film of the refractory metal provided on the wall surface of the through hole formed in the metal plate.   2. The light emitting element storage package according to claim 1, wherein heat generated from the light emitting element is transferred to the lower surface of the insulating base through the insulating base and the copper plating film of the thermal via and the insulating base. A light emitting element storage package comprising: a base body; and a heat sink plate for directly dissipating heat by connecting directly to the copper plating film of the thermal via.

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