JP2010123606A5 - - Google Patents

Description

Substrate with through electrode, light emitting device, and method for manufacturing substrate with through electrode

  The present invention relates to a substrate with a through electrode in which a through electrode is formed on a substrate used for an electronic component, a manufacturing method thereof, and a light emitting device using the substrate with a through electrode.

  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 light emission luminance of a single LED element is still weak compared to other light emitters, and it is therefore 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.

  Further, as a method for forming a through electrode without performing a high temperature treatment, a method of performing metal plating on a through hole formed in a package is known. However, there is a problem that the metal deposition rate by plating is slow and the productivity is poor. Furthermore, the through electrode deposited by the plating process tends to have a cavity inside. For this reason, there is a problem in that the sealing performance by the through electrode is lowered, moisture and impurities enter from the outside, and the reliability of the element is impaired. Moreover, the adhesiveness between a through-electrode and the immediate wall surface of a through-hole was weak, and there existed a subject that a through-electrode fell off by repeating a temperature change.

  In the case of a light emitting device, in addition to the through electrode formed in the package, it is necessary to form a reflective film in order to impart directivity to the light emitted from the light emitting element. However, the surface of the metal film formed by the plating process has a low reflectance or has a strong wavelength dependency. Therefore, the formation of the reflective surface and the formation of the through electrode cannot be performed at the same time, and there is a problem that the number of manufacturing steps increases.

  Therefore, in the present invention, the following configuration is adopted in order to solve the above problems.

(1) The light emitting device of the present invention includes a package substrate having a recess in the central portion, the Mino Kubo and light emitting element mounted on the bottom surface, the recess light reflective film formed by heat-treating the nano metal particles on the wall surface of the And a sealing material for sealing the light emitting element .

(2) A light reflecting film obtained by heat-treating nano metal particles is formed on the bottom surface of the recess.

(3) The package substrate is integrally formed of a glass material, a ceramic material, an aluminum nitride material, or a metal material .

(4) The package substrate includes a through electrode filled in a through hole penetrating from the bottom surface of the recess to the back surface, and the through electrode is obtained by heat treatment with nano metal particles attached to the side wall surface of the through hole. Including metal materials .

(5) The through electrode includes a first conductor obtained by heat treatment with nano metal particles attached to the side wall surface of the through hole, and a second conductor filled on the inner peripheral side of the first conductor. It was.

(6) The nano metal particles are nano silver particles, nano gold particles, or nano copper particles.

(7) In the method for manufacturing a light emitting device of the present invention, a step of forming a package substrate having a depression at the center, and nano metal particles are attached to the wall surface of the depression and heat-treated to form a light reflecting film. A step , a step of mounting a light emitting element on the bottom surface of the depression, and a step of sealing the light emitting element with a sealing material .

(8) A step of forming a hole in the bottom surface of the depression, a step of heat-treating the nanometal particles on the side wall surface of the hole, and a step of filling the hole with the nanometal particles attached thereto with a conductive material. It has been added .

(9) Before the step of attaching the nano metal particles, the wall surface of the recess or the side wall surface of the hole is replaced with a water-repellent surface.

  (10) In the step of forming the package substrate, the depression is formed by molding a package material.

  (11) In the step of molding the package material, the hole is formed simultaneously with the depression.

  (12) After the step of filling the conductive material, the method includes a step of grinding the back surface opposite to the surface on which the holes are formed, and exposing and planarizing the filled conductive material. .

(13) The nano metal particles are attached by printing the nano metal particles on the wall surface and bottom surface of the recess by an ink jet printing method.

According to the present invention, the light reflecting film obtained by firing the nano metal particles is formed on the wall surface of the recess of the package substrate. This makes it possible to improve the adhesion between the package substrate and the light reflecting film.

Embodiment 1 FIG. 1 is a schematic longitudinal sectional view of a light emitting device 1 according to Embodiment 1 of the present invention. In the light emitting device 1, the light emitting element 4 is mounted on the bottom surface of the recess 3 of the package substrate 2 by the die bonding material 9. A through-hole 11 is formed in the package substrate 2 so as to penetrate from the bottom surface of the recess 3 to the back surface. The through-hole 11 is filled with through-electrodes 7a and 7b. A light reflecting film 5 for reflecting the light emitted from the light emitting element 4 is formed on the wall surface of the recess 3 of the package substrate 2. An electrode (not shown) is formed on the back surface of the light emitting element 4 and is electrically connected to the through electrode 7 a through the die bonding material 9. Further, another electrode (not shown) is formed on the upper surface of the light emitting element 4, and is electrically connected to the through electrode 7 b through the wire 10.

  A sealing material 6 is applied to the recess 3 of the package substrate 2, and the light emitting element 4 and the wire 10 are sealed. Back electrodes 8 a and 8 b are formed on the back surface of the package substrate 2 so as to be electrically separated. That is, the light emitting element 4 can be supplied with power from the back electrodes 7a and 7b. Furthermore, when the light emitting element 4 emits light and generates heat, heat is transmitted to the back electrode 8a through the through electrode 7a, so that heat can be dissipated.

Here, the light reflection film 5 and the through electrodes 7a and 7b include a metal material obtained by heat-treating nano metal particles. The nano metal particles mean metal particles having a particle diameter of several nanometers to several tens of nanometers. The heat treatment of the nano metal particles is performed at a temperature of 100 ° C to 600 ° C. As the nano metal particles, for example, nano Ag particles, nano Au particles, and nano Cu particles can be used. The nano metal particles are dispersed in a solvent, adhered to the wall surface of the recess 3 and the side wall surface of the through hole 11 by a dispensing method or an ink jet printing method, and heat-treated to form a metal film. Nano metal particles have an extremely large surface area compared to other metal particles and bulk. For this reason, when the metal film is formed by baking after applying the nano metal particles, the adhesion to the substrate surface is improved. Moreover, since the nano metal particles have high reactivity, the firing temperature can be lowered as compared with the case of other metal particles.

Embodiment 2 FIG. 2 is a schematic longitudinal sectional view of a light emitting device 1 according to Embodiment 2 of the present invention. 1 is different from the first embodiment shown in FIG. 1 in that a light reflecting film 5 is also formed on the bottom surface of the recess 3 of the package substrate 2 and the through electrode 7 is composed of a first conductor X and a second conductor Y. is there. The same portions or portions having the same function are denoted by the same reference numerals.

The light emitting device 1 reflects the light emitted from the light emitting element 4 using the LED mounted on the bottom of the package substrate 2 having the depression 3 at the center, the depression 3, and the wall of the depression 3. The formed light reflecting film 5 is provided. The light emitting device 1 further includes through electrodes 7a and 7b formed in the through holes 11 penetrating from the bottom surface of the recess 3 to the back surface of the package substrate 2, and formed on the back surface of the package substrate 2, and the through electrodes 7a and 7b are electrically connected to each other. The back electrodes 8a and 8b are connected to each other. 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 the through electrode 7 b are connected by a wire 10 made of a gold wire.

The light reflecting film 5 formed on the wall surface and bottom surface of the recess 3 is formed by a printing method of nano metal particles. The through electrodes 7a and 7b are composed of a first conductor X and a second conductor Y. The first conductor X is formed by a printing method of nano metal particles. The second conductor Y is formed from a conductive paste in which a conductor filler and a resin binder are kneaded, or a conductive paste in which a conductor filler, glass frit and a resin binder are kneaded. Therefore, the light reflecting film 5 formed on the wall surface and the bottom surface of the recess 3 and the first conductor X formed on the side wall surface of the through hole 11 can be simultaneously formed by printing nano metal particles. Nano Ag particles can be used as the nano metal particles. This is because the Ag film is suitable for the light reflecting film 5 because of its high reflectance .

  The package substrate 2 uses a plate-like glass material, and the recesses 3 and the through holes 11 are formed by molding. Since the package substrate 2 is integrally formed so that there are no joint portions made of different materials, the durability is improved. Further, the package substrate 2 may be formed by bonding different materials in place of an integrated material using the same material. Moreover, since the firing of the nano metal particles does not require a high temperature treatment of 1000 ° C. or higher, the material selection range of the package substrate 2 is expanded. For example, in addition to the glass material, a ceramic material, an aluminum nitride material, or a metal material can be used. Moreover, you may form the hollow 3 and the through-hole 11 by the sandblasting method or the etching method.

  The light emitting element 4 and the wire 10 are sealed with a transparent sealing material 6. When a glass material is used for the package substrate 2, the sealing material 6 may be made from a metal oxide obtained by polymerizing and baking a metal alkoxide or a polymetalloxane formed from a metal alkoxide instead of a resin material. it can. In particular, when a metal oxide prepared from a metal alkoxide or polymetalloxane is used as the sealing material 6, since the package substrate 2 made of glass is also a silicon oxide, the thermal expansion coefficient is approximated and good adhesiveness is obtained. And sealing property can be obtained.

  The back electrodes 8a and 8b 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 substrate 2 and the back electrodes 8a and 8b are formed by metal vapor deposition or sputtering, a Ti layer, a barrier layer thereon, and a Pt layer thereon are provided to improve adhesion. An Au layer can be formed to prevent the layer or Ni layer and also 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 7a is provided under the light emitting element 4 and the back electrode 8a is connected to the through electrode 7a, the heat generated by the light emission of the light emitting element 4 is caused by the through electrode 7a and the back electrode 8a. 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. In addition, since the diameter of the recess 3 is enlarged from the lower part toward the upper part, the directivity can be imparted to the light emitted from the light emitting element 4.

  Here, the through electrodes 7a and 7b are constituted by a first conductor X formed on the wall surface of the through hole 11 and a second conductor Y filled in the inner peripheral portion thereof. The second conductor Y was formed by filling the inner peripheral side of the first conductor X with a conductive paste kneaded with a conductive filler and a resin binder and firing it. Since the nano metal particles have high reactivity, the nano metal particles and the conductor of the conductive paste diffuse to each other at the interface when firing the conductive paste. As a result, the first conductor X and the second conductor Y after firing have an interdiffusion layer or an alloy layer formed at the interface to be firmly bonded, and the adhesion is improved. Therefore, the through electrode 7 does not fall even when the temperature rise and fall of the package substrate 2 are repeated.

  Further, if the first conductor X is formed on the side wall surface of the through hole 11 with a thickness of 1 μm or more, the unevenness of the side wall surface of the through hole 11 can be filled to make a smooth surface. By smoothing the inner surface of the first conductor X, it becomes difficult for air bubbles to be taken in between the conductive paste and the surface of the first conductor X when the conductive paste is filled, so the first conductor X and the second conductor It is possible to prevent a decrease in adhesion with Y.

  As the substrate 2, a glass substrate or a ceramic substrate can be used. This is because the adhesion with the nano metal particles is excellent. The through-hole 11 is formed so that its diameter expands in a divergent shape from the back surface to the front surface. This is for facilitating application of the nano metal particles to the side wall surface of the through-hole 11, but is not an essential requirement.

  The surface of the through electrode 7 on the back surface of the package substrate 2 is planarized so as to be the same surface as the back surface of the package substrate 2. By flattening the surface in this way, it becomes easy to form electrodes on the back surface and mount the light emitting device 1 on other components.

  As the nanometal particles for forming the first conductor X, it is preferable to use nanosilver particles. This is because nano silver particles have excellent adhesion to the substrate and easily form an interdiffusion layer between the conductive paste. The nano silver particles are preferably formed with a thickness of 0.5 μm or more.

  (Embodiment 3) FIGS. 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 substrate 2 is formed. FIG. 3A shows a forming method. A glass material 15 is installed as a package material on the surface plate 16 and heated to a temperature of 300 ° C. to 800 ° C. at which the glass material 15 is softened. 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 becomes a hole for a 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 a temperature of 300 ° C. to 800 ° C. and pressed against the lower glass material 15. FIG. 3B is a longitudinal sectional view of the package substrate 2 after the molding process, and the recess 3 and the hole 20 are formed. In the third embodiment, the recess 3 has a mortar shape with a circular planar shape.

FIG. 4 shows a state in which nano silver particles are printed as nano metal particles on the wall surface and bottom surface of the recess 3 and the side wall surface of the hole 20 by the ink jet printing method. Before performing inkjet printing, the surface of the package substrate 2 is washed with hydrofluoric acid. Next, dry cleaning is performed with Ar plasma. Next, the side wall surface of the hole 20 is subjected to a fluorine-based surface treatment, dried at about 80 ° C., and replaced with a water-repellent surface. By substituting with a water repellent surface, it is possible to reduce ink dripping on the wall surface. Next, the package substrate 2 is heated to a temperature in the range of 70 ° C. to 100 ° C., and the nano silver particles dispersed in the solvent from the nozzles 14 of the ink jet printer 13 are formed on the wall surface, the bottom surface, and the side walls of the holes 20. Spray. In the ink jet printing, the light reflecting film 5a and the light reflecting film 5b are separated from each other. This is because it functions as two electrodes of the light emitting element 4 to be mounted later. Instead of the ink jet printing method, the nano metal particles may be applied by a dispensing method.

Since a large number of nozzles 14 are arranged in the direction perpendicular to the paper surface, printing can be performed in an arbitrary pattern on the surface. Since 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 surface of the package substrate 2 can be fixed to 2 mm to 3 mm. As a result, it is possible to print almost uniformly on the wall surface and bottom surface of the recess 3 and the side wall surface of the hole 20. After printing, baking is performed at a temperature of 450 ° C. to 550 ° C. As a result, the light reflecting films 5 a and 5 b are firmly attached to the wall surface and the bottom surface of the recess 3, and the first conductors Xa and Xb made of the nano Ag film are firmly attached to the sidewall surface of the hole 20.

  FIG. 5 is a longitudinal sectional view showing a state in which the holes 20 formed in the package substrate 2 are filled with the second conductors Ya and Yb. 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. Then, it solidified by baking at a temperature of about 200 ° C. By this firing, the nano Ag films of the first conductors Xa and Xb and the Ag of the conductive paste diffuse to each other, and an interdiffusion layer is formed at the interface. Accordingly, the first conductors Xa and Xb and the second conductors Ya and Yb are firmly coupled. The through electrode 7a composed of the first conductor Xa and the second conductor Ya and the through electrode 7b composed of the first conductor Xb and the second conductor Yb are electrically separated. Further, instead of the conductive paste, a metal core material and glass frit may be inserted and filled to be solidified.

Thus, since the light reflection film 5 and the first conductor X of the through electrode 7 can be manufactured in the same process, the number of manufacturing processes can be reduced and the product cost can be reduced.

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

  FIG. 7 is a 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 substrate 2. Ink mixed with a conductive material such as Ag is printed on the back surface of the package substrate 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 electrodes 8a and 8b may be formed by depositing and patterning a metal film by another method such as sputtering, vapor deposition or plating.

  FIG. 8 is a schematic longitudinal sectional view showing a state in which the light emitting element 4 is mounted in the recess 3 of the package substrate 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 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. A gold fine wire can be used as the wire 10. Instead of connecting using the wire 10, the light emitting element 4 is extended to the through electrode 7b, and the back surface of the light emitting element 4 is made to correspond to the through electrodes 7a and 7b to form two electrodes. May be connected together electrically and mechanically.

  FIG. 10 is a 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, the silicon oxide which superposed | polymerized and hardened the polymetalloxane formed from the metal alkoxide or metal alkoxide can be formed.

  As described above, according to the method for manufacturing a light emitting device of the present invention, nano metal particles are printed on the wall surface, bottom surface, and through-electrode hole 20 of the recess 3 by a printing method. The through electrode 7 having good adhesion can be produced without requiring metallization by treatment. In addition, since the inkjet printing method is applied as the printing method, a highly accurate printing pattern can be formed on a stepped surface. In addition, since the nano metal particles are attached or printed only on a necessary portion, the material to be used can be reduced as compared with the method of removing the etching by leaving the necessary portion on the entire surface after forming the electrode.

  In the third embodiment, the example in which the package substrate 2 is molded by the molding method has been described. However, the present invention is not limited to this. For example, a structure in which a plate-like body in which the through electrode 7 is formed on the package substrate 2 and a frame for forming the recess 3 are bonded to the plate-like body can be used. Further, the recess 3 of the package substrate 2 may be formed by a sandblasting method or an etching method.

  In the third embodiment, (1) glass material formation → (2) formation of through electrode → (3) flattening of back surface → (4) formation of back electrode → (5) mounting of light emitting element → ( 6) Although it is the order of formation of a sealing material, it is not limited to this process order. For example, after forming the through electrode, (5) mounting of the light emitting element → (6) formation of the sealing material → (3) planarization of the back surface → (4) formation of the back surface electrode may be performed. .

  (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. 8 to 10 in the third embodiment, and shows a pattern of the back surface electrodes 8 a and 8 b formed on the back surface of the package substrate 2. FIG. 11B is a schematic rear view in which one package substrate 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 substrate 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 7a and 7b may be set as appropriate 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.

DESCRIPTION OF SYMBOLS 1 Light emitting device 2 Package board 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 11 Through hole X 1st conductor Y 2nd conductor

Claims (13)

A package substrate having a depression in the center,
A light emitting device mounted on the bottom surface of the recess;
A light reflection film formed by heat-treating the nano metal particles on the wall surface of the recess,
A light-emitting device comprising: a sealing material that seals the light-emitting element . The light emitting device according to claim 1 , wherein a light reflecting film obtained by heat-treating nano metal particles is formed on a bottom surface of the depression. The light emitting device according to claim 1, wherein the package substrate is integrally formed of a glass material, a ceramic material, an aluminum nitride material, or a metal material.   The package substrate includes a through electrode filled in a through hole penetrating from the bottom surface of the recess to the back surface, and the through electrode is a metal material obtained by heat treatment with nano metal particles attached to the side wall surface of the through hole The light emitting device according to claim 1, wherein the light emitting device includes: The through electrode comprises a first conductor obtained by heat treatment by attaching nano metal particles to a side wall surface of the through hole, and a second conductor filled on the inner peripheral side of the first conductor. The light emitting device according to claim 4 . The nano metal particles, light-emitting device according to any one of claims 1 to 5, characterized nanosilver particles that are nano gold particles or nano copper particles. Forming a package substrate having a depression in the center;
Attaching nano metal particles to the wall surface of the depression, and heat-treating it to form a light reflecting film ;
Mounting a light emitting element on the bottom of the recess;
Sealing the light emitting element with a sealing material.   Forming a hole in the bottom of the recess;
  Attaching nano metal particles to the side wall surface of the hole and heat-treating;
  The method of manufacturing a light emitting device according to claim 7, further comprising a step of filling a conductive material in the hole to which the nano metal particles are attached. 9. The method for manufacturing a light emitting device according to claim 7 , wherein the wall surface of the recess or the side wall surface of the hole is replaced with a water repellent surface before the step of attaching the nano metal particles. In the step of forming the package substrate, method of manufacturing the light emitting device according to any one of claims 7-9, wherein the recess is formed by molding a packaging material. The method for manufacturing a light emitting device according to claim 10, wherein in the step of molding the package material, the hole is formed simultaneously with the depression. 2. The method of claim 1, further comprising: after the step of filling the conductive material, grinding a back surface opposite to the surface on which the hole is formed to expose the filled conductive material and planarize. Item 9. A method for manufacturing a substrate according to Item 8 . 13. The light emitting device according to claim 7, wherein the attachment of the nano metal particles is performed 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.