JP2010123605A - Light-emitting device and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture a reliable light-emitting device 1 having improved adhesion of a light reflection film 5 by a simple manufacturing method. <P>SOLUTION: The light-emitting device 1 includes: a package 2 having a dent at the center; a light-emitting element 4 stored in the dent 3 and packaged at the bottom of the dent 3; the light reflection film 5 formed on the wall and bottom surfaces of the dent 3 by printing nano metal particles; and a sealing material 6, and the like for sealing the light-emitting element 4. Accordingly, the light-emitting device 1 having a simplified manufacturing method can be provided by improving adhesion to the package 2 of the light reflection film 5. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a structure of a light emitting device in which a light emitting element is mounted in a package, and a method for manufacturing the same.

  Surface light emitting elements, particularly LEDs (Light Emitting Diodes), have recently been improved in light emission luminance and the like, and are expected to expand their applications. Conventionally, LEDs are mounted on a plastic case, and a microlens or the like is focused in the middle of the optical path, or the entire substrate on which the LEDs and LEDs are mounted is molded with a transparent resin, and the surface of the resin is finished to a smooth spherical surface. As a result, the resin was condensed as a lens. Light emitting devices mounted with such LEDs are used, for example, as backlights for liquid crystal display devices, light emitting elements for traffic lights, large electronic bulletin boards, video screens, and other illuminations. LEDs can be driven with low voltage and low power consumption, and their emission luminance and emission life have been improved, so that they are expected to be applied to a wide range of fields such as indoor lighting, automobile lighting, and backlights for liquid crystal display screens.

  However, the luminous intensity of a single LED element is still weak compared to other light emitters. For this reason, it is necessary to configure a light emitter by combining a large number of LED elements. Further, when the emission intensity of the LED element is increased, the amount of heat generation increases. Since the luminous efficiency is lowered when the LED element is heated, it is necessary to adopt a structure that can effectively dissipate heat. Moreover, in order to replace with other light emitters such as a fluorescent lamp, it is necessary to simplify the manufacturing process and reduce the manufacturing cost.

Patent Document 1 describes an LED package in which a ceramic green sheet having a conductor film printed on its surface is molded to form a cavity, and an LED is mounted on the bottom of the cavity. A reflective layer made of a conductor film is formed on the side surface of the cavity. This reflective layer is formed by forming a conductor film on the green sheet before being formed by printing, pressing it so that the conductor film is positioned on the inclined part of the cavity, and then performing metallization by firing to reflect light. It is as a layer. A through hole is formed at the bottom of the cavity, and wiring is drawn out to the back side through the through hole.
JP 9-45965 A

  However, in the LED package described in Patent Document 1, a conductor film for an electrode and a reflective film is formed before firing, and then a cavity is formed by press working and fired. Since this firing is a ceramic sintering, a high temperature treatment of 1000 ° C. or higher is required. For this reason, the time for passing through the manufacturing process becomes longer, and the electrode pattern is printed and then subjected to press working and high-temperature heat treatment, so that there is a limit to the accuracy of the outer shape of the cavity and the high definition of the electrode pattern.

In the present invention, in order to solve the above problems, the following configuration is adopted.
(1) A package having a depression at the center, a light emitting element housed in the depression and mounted on the bottom of the depression, and light reflection formed by heat-treating nano metal particles on the wall and bottom of the depression. A light emitting device including a film and a sealing material for sealing the light emitting element was obtained.

  (2) In the light emitting device of (1), the nano metal particles are nano silver particles.

  (3) In the light emitting device according to (1) or (2), the package is integrally formed of a glass material, a ceramic material, an aluminum nitride material, a metal material, or a resin material.

  (4) In the light emitting device according to any one of the above (1) to (3), the recess formed in the center has a shape in which the diameter expands from the bottom to the top of the recess.

  (5) A step of forming a package having a depression at the center, a step of attaching nano metal particles to the wall surface and bottom surface of the depression, heat-treating it to form a light reflecting film, and a light emission on the bottom surface of the depression The light emitting device manufacturing method includes a step of mounting an element and a step of sealing the light emitting element with a sealing material.

  (6) In the method for manufacturing a light-emitting device according to (5), a step of replacing the wall surface of the depression with a water-repellent surface is provided before the step of forming the light reflecting film.

  (7) In the method for manufacturing a light emitting device according to (5) or (6), in the step of forming a package, the depression is formed by molding a package material.

  (8) In the method for manufacturing a light-emitting device according to (7), in the forming step, a through-electrode hole is formed at the bottom of the recess at the same time as the recess.

  (9) In the method for manufacturing a light-emitting device according to any one of (5) to (8), the nano metal particles are attached by printing the nano metal particles on the wall surface and the bottom surface of the depression by an inkjet printing method. I decided to let them.

  (10) In the method for manufacturing a light-emitting device according to any one of (5) to (9), a step of forming a through electrode penetrating from the bottom of the recess toward the back surface of the package, and a through electrode on the back surface of the package And a step of forming a back electrode that is electrically connected to the substrate.

  (11) In the method for manufacturing a light-emitting device according to any one of (5) to (10), the package is made of a glass material.

  The light emitting device according to the present invention has a recess in the center of the package, a light emitting element is mounted on the bottom surface of the recess, and a light reflecting film is formed on the wall surface and bottom surface of the recess by heat treatment of nano metal particles. . Thereby, the adhesiveness of the wall surface of a hollow and a light reflection film improves, and a reliable light-emitting device can be provided.

(Embodiment 1)
FIG. 1 is a schematic longitudinal sectional view of a light emitting device 1 according to Embodiment 1 of the present invention. The light emitting device 1 is formed on the wall surface and the bottom surface of the recess 3 in order to reflect the light emitted from the package 2 having the recess 3 at the center, the light emitting element 4 mounted on the bottom of the recess 3, and the light emitting element 4. A light reflecting film 5 is provided. The light emitting device 1 further includes through electrodes 7 a and 7 b that penetrate from the bottom surface of the recess 3 to the back surface of the package 2, and a back electrode 8 that is formed on the back surface of the package 2 and is electrically connected to the through electrode 7. Yes. The light emitting element 4 is mounted on the through electrode 7a via a die bonding material 9. An electrode pad (not shown) is formed on the light emitting element 4, and the electrode pad and an electrode formed on the through electrode 7 b are connected by a wire 10.

  The light reflecting film 5 formed on the wall surface and bottom surface of the depression 3 was formed by heat-treating nano metal particles. Here, the nano metal particle means a metal particle having a diameter of several nm to several tens of nm. For example, nano silver particles are dispersed in a binder resin and printed by, for example, an ink jet printing method. A heat treatment at 100 ° C. to 500 ° C. is performed after printing. Thereby, the light reflection film 5 with good adhesion can be formed. When printing and metallizing ordinary silver particles, it is necessary to perform heat treatment at 1000 ° C or higher. However, when nano silver particles are used, the surface area of the particles is large and the reactivity is high. Good adhesion can be obtained. In addition, since it is not necessary to perform patterning by a photo process, the manufacturing process can be simplified, and the manufacturing cost of the light emitting device 1 can be reduced.

  The package 2 used a plate-like glass material, and formed a recess 3 and a hole for the through electrode 7 by molding. Since the package 2 is integrally formed and does not have a joint portion made of different materials, durability can be improved. The package 2 may be integrally formed by joining different materials in place of a single body using the same material. In addition, since the nanometal particles have improved adhesion to the substrate at a relatively low heat treatment temperature, the range of materials for the package 2 is expanded. For example, in addition to the glass material, a ceramic material, an aluminum nitride material, a metal material, or a resin material can be used. Further, although the recess 3 and the hole 20 for the through electrode 7 are formed by molding, it may be formed by a sandblasting method or an etching method instead.

  The through electrode 7 can be formed by filling and solidifying a conductive paste containing Ag in a through hole or hole 20 provided in the bottom of the recess 3 of the package 2. Further, instead of the conductive paste or together with the conductive paste, a metal material such as Kovar, Ni, Fe, or Cu can be filled and solidified by heating. In addition, a metal core material can be inserted and fixed. Further, it can be formed by filling with molten solder and solidifying by cooling.

  The light emitting element 4 can use LED. The light emitting element 4 is mounted on the through electrode 7a through a die bonding material 9. Further, an electrode (not shown) formed on the surface of the light emitting element 4 and the through electrode 7b are electrically connected by a wire 10 made of Au. The light emitting element 4 and the wire 10 are sealed with a sealing material 6. A transparent resin material can be used as the sealing material 6. When the package 2 is made of a glass material, the sealing material 6 can be a metal oxide obtained by polymerizing and baking a metal alkoxide or a polymetalloxane formed from a metal alkoxide instead of a resin material. In particular, when a metal oxide formed from a metal alkoxide or polymetalloxane is used as the sealing material 6, since the package 2 made of glass is also a silicon oxide, the thermal expansion coefficient approximates and good adhesiveness is obtained. And sealing property can be obtained.

  The back electrode 8 can be formed by a metal vapor deposition method, a sputtering method, or a conductive material printing method. According to the printing method, since the conductive film is deposited and patterned at the same time, the manufacturing process can be simplified. When glass is used as the material of the package 2 and the back electrode 8 is formed by metal vapor deposition or sputtering, a Ti layer, a barrier layer thereon, a Pt layer thereon, or An Ni layer can be formed as well as an Au layer to prevent surface oxidation. Alternatively, it may be formed by a lift-off method in which an electrode pattern is first formed from a photosensitive resin, for example, a resist, a metal film is deposited thereon, and the resist is removed.

  Thus, since the through electrode 7 is provided below the light emitting element 4 and the back electrode 8 is connected to the through electrode 7, the heat generated by the light emission of the light emitting element 4 is caused by the through electrode 7 and the back electrode 8. The heat can be efficiently radiated to the outside through the. Therefore, even when a plurality of light emitting elements 4 are provided in one depression 3 to improve the light emission luminance, it is possible to prevent the light emission efficiency from being lowered due to heating. Further, as shown in FIG. 1, since the diameter of the recess 3 is widened from the lower part to the upper part, the light emitted from the light emitting element 4 emits light having directivity in the upper direction. Can be made.

(Embodiment 2)
FIG. 2 shows a schematic longitudinal sectional view of the light emitting device 1 according to Embodiment 2 of the present invention. The difference from the first embodiment is that, instead of providing through holes and through electrodes 7 in the package 2, electrodes are formed on the top and side surfaces of the package 2 and connected to the back electrode 8. The part of is the same.

  A recess 3 is formed in the center of the package 2. The central recess 3 can be formed by molding, sandblasting, etching, or the like. Light reflecting plates 5a and 5b are formed on the inner wall surface and bottom surface of the recess 3 by a printing method of nano metal particles. Upper surface electrodes 21 a and 21 b are formed on the upper surface of the package 2, and side surface electrodes 22 a and 22 b are formed on the side surfaces of the package 2. The upper surface electrodes 21a and 21b and the side surface electrodes 22a and 22b can be formed by a printing method of nano metal particles continuously with the light reflecting films 5a and 5b. On the back surface of the package 2, back surface electrodes 8a and 8b are formed. The light reflecting film 5a, the top electrode 21a, the side electrode 22a, and the back electrode 8a are electrically connected to form one electrode. The light reflecting film 5b, the top electrode 21b, the side electrode 22b, and the back electrode 8b are electrically connected to form the other electrode.

  The light emitting element 4 is mounted on the light reflecting film 5 a on the bottom surface of the recess 3 via a die bonding material 9. An electrode (not shown) is formed on the upper surface of the light emitting element 4, and the electrode of the light emitting element 4 and the light reflecting film 5 on the recess 3 are connected by a wire 10. That is, the light reflecting films 5a and 5b function as conductors for supplying power for driving the light emitting element 4, and power is supplied through the back electrodes 8a and 8b, the side electrodes 22a and 22b, and the top electrodes 21a and 21b. The These electrodes also have a function of radiating heat generated by the light emitting element 4. The light emitting element 4 and the wire 10 are sealed by applying a sealing material 6.

  In addition, in the said Embodiment 1 and Embodiment 2, although the inclined surface of the hollow 3 has a fixed angle, it is not limited to this. The inclined surface can be formed in a curved shape, for example, a bowl shape. If a bowl-shaped reflecting surface is used, the directivity of reflected light can be further increased.

(Embodiment 3)
3-10 is a schematic diagram showing the manufacturing method of the light-emitting device 1 which concerns on Embodiment 3 of this invention.

  FIG. 3 shows how the package material is molded. FIG. 3A is a schematic diagram showing a forming method. For example, a glass material 15 is installed on the surface plate 16 as a package material, and the glass material 15 is softened and heated to about 300 ° C. to about 800 ° C. A convex portion 18 and a concave portion 19 are formed on the surface of the mold 17. The convex portion 18 is a portion that hits the hole 20 for the through electrode, and the concave portion 19 is a portion that becomes a bank around the recess 3. The mold 17 is also heated to about 300 ° C. to about 800 ° C. and pressed against the lower glass material 15. FIG. 3B is a schematic longitudinal sectional view of the package 2 after the molding process, and the recess 3 and the hole 20 are formed. In the fourth embodiment, the recess 3 has a mortar shape with a circular planar shape.

  FIG. 4 shows a state in which nano metal particles, for example, nano silver particles are printed by an ink jet printing method. Nano silver particles dispersed in a solvent are ejected from the nozzle 14 of the ink jet printer 13. A large number of nozzles 14 are arranged in the direction perpendicular to the paper surface. Therefore, it can be printed on a sheet. The inkjet printer 13 is moved relative to the package 2 to print on the wall surface of the recess 3 and the bottom surface of the recess 3 in a predetermined pattern. The droplets ejected from the nozzle 14 are ejected in a very small amount like a bullet. The gap between the tip of the nozzle 14 and the printing surface can be fixed to 2 mm to 3 mm. Therefore, a predetermined high-definition pattern can be printed even when printing on an uneven surface. In addition, the nano metal particles can be printed on the side surface of the hole 20 as well as the wall surface of the recess 3 and the bottom surface of the recess 3. The light reflecting film 5a and the light reflecting film 5b are electrically separated from each other.

  Note that it is desirable to replace the surface of the package 2 with a water-repellent surface before printing in order to prevent ink dripping when printed on the wall surface of the recess 3. For example, a fluorine resin is coated. Thereby, when nano metal particles adhere, dripping can be prevented and printing can be performed in a desired thickness and shape. Further, when wavelength selectivity is imparted to the light reflected from the light reflecting film 5, a thin film such as Au can be further deposited.

  FIG. 5 is a schematic longitudinal sectional view showing a state where the through electrode 7 is filled in the hole 20 formed in the package 2. The hole 20 shown in FIG. 4 is filled with a conductive paste containing a metal such as Ag by a dispenser or the like, and heated and solidified to form the through electrode 7. The through electrode 7a and the through electrode 7b are electrically separated. Further, instead of the conductive paste, a metal core material may be inserted and filled to be solidified.

  FIG. 6 is a schematic longitudinal sectional view showing a state where the back surface of the package 2 is polished and the through electrode 7 is exposed to the back surface side. The package 2 is placed on a polishing surface plate or polishing pad having a flat surface, and the package 2 is relatively moved while being pressed through an abrasive and polished. Thereby, the exposed surface of the back surface of the through electrode 7 and the back surface of the package 2 can be planarized. Further, by flattening in this way, the package 2 can be easily mounted on other components.

  FIG. 7 is a schematic longitudinal sectional view showing a state in which the back electrodes 8 a and 8 b are formed on the back surface of the package 2. Ink mixed with a conductive material such as Ag is printed on the back surface of the package 2 by a screen printing method. Next, it heat-fires and solidifies. Since the back electrodes 8a and 8b are formed by printing, the photolithography process and the etching process are not required, and the manufacturing cost can be reduced. Further, instead of the screen printing method, the back electrode 8 may be deposited and patterned by another method such as sputtering, vapor deposition, or plating.

  FIG. 8 is a schematic longitudinal sectional view showing a state where the light emitting element 4 is mounted in the recess 3 of the package 2. The light emitting element 4 is placed on the exposed surface of the through electrode 7a with the die bonding material 9 interposed therebetween, and the die bonding material 9 is cured and bonded in a heating furnace. The die bonding material 9 is conductive, and an electrode (not shown) is formed on the back surface of the light emitting element 4, and mechanically and electrically connects the through electrode 7 a and the light emitting element 4. As the die bonding material 9, solder bumps or gold bumps can be used. In addition, a conductive adhesive can be used as the die bonding material 9.

  FIG. 9 is a schematic longitudinal sectional view showing a state where the light emitting element 4 and the through electrode 7 b are connected by the wire 10. An electrode (not shown) is formed on the upper surface of the light emitting element 4. Gold fine wire can be used as the wire. Instead of connecting the electrode formed on the surface of the light emitting element 4 and the through electrode 7b with the wire 10 made of a conductor, the light emitting element 4 is extended to the through electrode 7b, and the through electrode is formed on the back surface of the light emitting element 4. An electrode may be formed at a position corresponding to 7a and 7b and electrically connected to the two through electrodes 7a and 7b all together by surface mounting.

  FIG. 10 is a schematic longitudinal sectional view showing a state in which the light emitting element 4 is sealed by applying the sealing material 6 to the recess 3. As the sealing material 6, an insulating transparent resin material can be used. Moreover, it can be set as the silicon oxide which superposed | polymerized and hardened the polymetalloxane formed from the metal alkoxide or metal alkoxide.

  As described above, according to the method for manufacturing a light-emitting device of the present invention, the nano metal particles are printed on the wall surface and bottom surface of the recess 3 by the printing method, so that metallization by high-temperature treatment as in the conventional example is not required. Thus, it is possible to form the light reflecting film 5 and the electrode having good adhesion. Therefore, the range of materials of the package 2 that can be used is expanded, and glass materials or resin materials can be used in addition to ceramics and metals. Further, by applying an inkjet printing method as a printing method, a highly accurate printing pattern can be formed on a surface having a step. Moreover, a complicated pattern can be easily formed on the bottom surface of the recess 3. In addition, since nano metal particles are applied or printed only on necessary portions, resources can be effectively used as compared with a method in which the necessary portions are left behind and etched away after electrode formation on the entire surface.

  In addition, in the said Embodiment 3, although the example which shape | molded the package 2 by the shaping | molding method is shown, it is not limited to this. For example, a structure in which a plate-like body in which the through electrode 7 is formed in the package 2 and a frame for forming the depression 3 are bonded to the plate-like body can be used. Moreover, you may form the hollow 3 of the package 2 by the sandblasting method or the etching method.

  In the third embodiment, (1) glass material formation → (2) formation of light reflecting film → (3) formation of through electrode → (4) flattening of the back surface → (5) formation of the back electrode → (6) Mounting of light emitting element → (7) The order of forming the sealing material, but not limited to this process order. For example, (3) after formation of the through electrode, (6) mounting of the light emitting element → (7) formation of the sealing material → (4) planarization of the back surface → (5) formation of the back surface electrode good.

(Embodiment 4)
FIG. 11 is a schematic diagram for explaining a method for manufacturing a multi-cavity light-emitting device 1 according to Embodiment 4 of the present invention. For example, in the manufacturing method of the light emitting device 1 according to the third embodiment, 86 light emitting devices 1 are manufactured simultaneously from one wafer 30.

  FIG. 11A corresponds to any of FIGS. 7 to 10 in the third embodiment, and shows a pattern of the back surface electrode 8 formed on the back surface of the package 2. FIG. 11B is a schematic rear view in which a portion of one package 2 is enlarged. As shown in FIG. 11B, four through electrodes 7 a are formed in the region of the light emitting element 4, and one through electrode 7 b is formed outside the light emitting element 4. By forming the four through electrodes 7 a in the region of the light emitting element 4, the heat generated in the light emitting element 4 can be effectively dissipated. The back electrode 8 is electrically separated into back electrodes 8a and 8b with the electrode separation region 33 as a boundary.

  One package 2 is partitioned by a vertical cutting line 31 and a horizontal cutting line 32. After the process shown in FIG. 10 of the third embodiment, the light emitting devices 1 are separated along the vertical cutting lines 31 and the horizontal cutting lines 32. Separation can be performed by dicing or scribing. Note that the number to be obtained is not limited to the fourth embodiment. Further, the number and diameter of the through electrodes 8a and 8b may be appropriately determined depending on the number of the light emitting elements 4, the supplied current, the heat radiation amount, and the like.

It is a typical longitudinal section of a light emitting device concerning an embodiment of the present invention. It is a typical longitudinal section of a light emitting device concerning an embodiment of the present invention. It is a schematic diagram showing the manufacturing method of the light emitting device which concerns on embodiment of this invention. It is a schematic diagram showing the manufacturing method of the light emitting device which concerns on embodiment of this invention. It is a schematic diagram showing the manufacturing method of the light emitting device which concerns on embodiment of this invention. It is a schematic diagram showing the manufacturing method of the light emitting device which concerns on embodiment of this invention. It is a schematic diagram showing the manufacturing method of the light emitting device which concerns on embodiment of this invention. It is a schematic diagram showing the manufacturing method of the light emitting device which concerns on embodiment of this invention. It is a schematic diagram showing the manufacturing method of the light emitting device which concerns on embodiment of this invention. It is a schematic diagram showing the manufacturing method of the light emitting device which concerns on embodiment of this invention. It is a schematic diagram showing the manufacturing method of multi-cavity of the light emitting device which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light emitting device 2 Package 3 Dimple 4 Light emitting element 5 Light reflection film 6 Sealing material 7 Through electrode 8 Back surface electrode 9 Die bonding material 10 Wire

Claims (11)

A package having a depression in the center,
A light emitting device housed in the depression and mounted on the bottom of the depression;
A light reflection film formed by heat-treating nano metal particles on the wall surface and bottom surface of the depression;
A light-emitting device comprising: a sealing material that seals the light-emitting element.   The light emitting device according to claim 1, wherein the nano metal particles are nano silver particles.   The light emitting device according to claim 1, wherein the package is integrally formed of a glass material, a ceramic material, an aluminum nitride material, a metal material, or a resin material.   The light emitting device according to any one of claims 1 to 3, wherein the recess formed in the center has a shape in which the diameter expands from the bottom to the top of the recess. Forming a package having a depression in the center;
A step of attaching nano metal particles to the wall surface and bottom surface of the recess, and heat-treating the nano metal particles,
Mounting a light emitting element on the bottom of the recess;
Sealing the light emitting element with a sealing material.   6. The method of manufacturing a light emitting device according to claim 5, further comprising a step of replacing the wall surface of the depression with a water repellent surface before the step of forming the light reflecting film.   The method for manufacturing a light emitting device according to claim 5, wherein in the step of forming the package, the recess is formed by molding a package material.   The method for manufacturing a light-emitting device according to claim 7, wherein in the forming step, a hole for a through electrode is formed at the bottom of the recess simultaneously with the recess.   9. The light emitting device according to claim 5, wherein the nano metal particles are attached by printing and attaching the nano metal particles to a wall surface and a bottom surface of the recess by an ink jet printing method. Method. Forming a through electrode penetrating from the bottom of the recess toward the back surface of the package;
The manufacturing method of the light-emitting device of any one of Claims 5-9 including the process of forming the back surface electrode electrically connected to the said penetration electrode in the back surface of the said package. The method for manufacturing a light emitting device according to claim 5, wherein the package is made of a glass material.

Images