JP2008010591A - Light emitting device, manufacturing method thereof, package, and substrate for mounting light emitting element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device along with its manufacturing method, a package, and a substrate for mounting a light emitting element, capable of preventing sulphiding on the surface of silver plating applied on an internal lead which is exposed from the inside surface of an opening of a support body of an LED, and capable of preventing degradation in maintenance coefficient of the optical output as time passes. <P>SOLUTION: In a package 1, an internal lead 13a is exposed on a part of the inside surface of an opening of a support body 11 comprising the opening for storing a light emitting element. An external lead 13b which is electrically conductive to the internal lead is led outside the support body, with at least the internal lead being applied with silver plating 14. An LED chip 15 is mounted inside the opening of the support body, and an electrode 15a is electrically connected to the internal lead. A thin film coat 16 for preventing sulphiding of silver plating with film thickness being 1 μm or less is formed to cover at least the silver plating surface of the internal lead, inside the opening of the support body. The thin film coat 16 is provided by injecting the solution of specified resin, and then letting a solvent to evaporate to cure the resin. Further, a translucent resin 17 is embedded to cover at least the thin film coat and the LED chip, inside the opening part of the support body. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a light emitting device and a method for manufacturing the same, and more particularly, to a light emitting device having a structure in which a light emitting element is housed on the bottom of an opening and the light emitting element is sealed with a translucent resin, and a method for manufacturing the light emitting device. The present invention relates to a light-emitting device having a structure in which an element is mounted and the light-emitting element is sealed with a light-transmitting resin, and a manufacturing method thereof.

  Today, various light emitting devices such as a surface mount type and a shell type are used in various fields. In a light-emitting diode (LED) which is an example of a light-emitting device, an LED chip is die-bonded with a light-transmitting resin on a substrate serving as a support. The LED chip is covered with a translucent resin that is electrically connected to each electrode using a wire or the like and protects the LED chip as desired.

  As the resin that is injected into the opening of the substrate after die bonding and wire bonding of the LED chip, a resin that is generally insulating and translucent and that is liquid at room temperature is used. As a specific example, a thermosetting resin such as an epoxy resin, an acrylate resin, a urethane resin, a silicone resin, or a polyimide resin, or a thermoplastic resin such as an acrylic resin, a polycarbonate resin, or a polynorbornene resin is used.

  When a thermosetting resin is used, a translucent resin can be formed by heating for resin curing. As a feature of the thermosetting resin, a resin that can be molded by a simple method such as compression molding with a thermosetting reaction at the time of molding can be obtained. About heat resistance, it is generally superior to thermoplastic resin.

  Moreover, when a thermoplastic resin is used, a translucent resin can be formed by volatilizing a solvent. The thermoplastic resin is characterized by a linear polymer in terms of chemical structure. Moreover, it can process efficiently by extrusion molding and injection molding, and a defective product can be reused. Furthermore, it is easier to mold a transparent resin than a thermosetting resin, and is excellent in translucency.

In addition, in the semiconductor light-emitting device of patent document 1, the point which forms the fluorescent film layer which covers the surface of a light emitting element mount part is disclosed. Moreover, in the LED lamp of patent document 2, the point which forms the coating layer which covers the inner surface of the cup surrounding LED chip is disclosed. These coating layers in Patent Documents 1 and 2 contain a phosphor and require a considerable film thickness in order to fix the phosphor. Moreover, in the light-emitting device of patent document 3, the point which forms the film | membrane which consists of transparent polyimide silicone resin containing fluorescent substance in the opening part of a resin substrate is disclosed. In this case, a film of transparent polyimide silicone resin containing an additive that changes the color tone is formed with a film thickness of 100 μm.
JP 2000-150966 A JP 2002-50799 A JP 2006-60005 A

  By the way, with the recent increase in output of LED chips, silicone resins having high heat resistance and light resistance have been frequently used. Silicone resin has translucency and is easy to seal the LED chip by dropping or the like, and thus is widely used for light emitting devices having openings. In order to improve the light extraction efficiency when forming a light emitting device having a structure in which the LED chip is housed on the bottom surface of the opening and the LED chip is sealed with a translucent resin, the internal leads exposed in the opening Many structures are used in which silver plating is applied.

  However, when sealing with a silicone resin, the silicone resin easily transmits gas. For example, in a light emitting device for outdoor use such as in-vehicle use, there arises a problem that silver plating of internal leads is easily sulfided. There is a problem that the silver plating is blackened due to the sulfurization of the silver plating, and the light output of the light emitting device is reduced.

  As a result of earnest research to solve the above-mentioned problems, the present inventor has reached the present invention, and the present invention is directed to sulfidation of the surface of silver used in the above-described internal lead, reflector part, etc. An object of the present invention is to provide a light emitting device that can prevent the decrease in the maintenance ratio of the light output with time and a method for manufacturing the same.

  In the light emitting device according to the first aspect of the present invention, the internal lead is exposed on the inner surface of the opening of the support having the opening for accommodating the light emitting element, and the external lead electrically connected to the internal lead is drawn out of the support. A package in which silver is used at least for the exposed portion of the internal lead, and a thin film coat made of a predetermined substance formed so as to cover at least the silver surface of the internal lead on the inner surface of the opening of the support. And a light-emitting element mounted in the opening of the support and having an electrode electrically connected to the internal lead. The light emitting device may further include a light transmissive resin that seals at least the light emitting element in the opening of the support.

  A light emitting device according to a second aspect of the present invention has a wiring pattern formed, and at least a part of the wiring pattern is formed so as to cover the surface of the light emitting element mounted with silver plating and the surface of the silver plating. And a light emitting element having an electrode mounted on the substrate and electrically connected to the wiring pattern. This light-emitting device can further include a light-transmitting resin that seals at least the light-emitting element.

In each of the light emitting devices, the thin film coat has a function of hardly transmitting a sulfur component, and H ₂ S permeability is 100 × 10 ⁻⁹ (ml · cm / sec · cm ² · cmHg) or less, or The SO ₂ permeability is preferably 150 × 10 ⁻⁹ (ml · cm / sec · cm ² · cmHg) or less. The film thickness is preferably 50 μm or less, particularly 30 μm or less, and more preferably 10 μm or less. The predetermined substance forming the thin film coat is epoxy resin diluted with a solvent, oxetane resin, urethane resin, acrylate resin, polyimide resin, fluororesin, silsesquioxane derivative, modified silicone resin, acrylic resin, polycarbonate resin Alternatively, at least one solution of polynorbornene resin is used and is formed by volatilizing the solvent.

  In the light emitting device of each of the inventions, the translucent resin is preferably a silicone resin, but may be other resins. The translucent resin may contain a wavelength conversion substance and / or an inorganic filler. At this time, it is desirable that the thermal expansion coefficient approximates that of the substrate, the package, and the LED chip to prevent the translucent resin from being separated from the package. For example, by using an InGaN-based blue light-emitting LED chip as a light-emitting element and a YAG phosphor as a wavelength conversion material, a white light-emitting LED device can be easily and inexpensively realized.

  A method for manufacturing a light emitting device according to a third aspect of the present invention is a method for manufacturing a light emitting device having a light emitting element and a package on which the light emitting element is mounted, the support having an opening for accommodating the light emitting element. An internal lead is exposed on the inner surface of the opening, an external lead electrically connected to the internal lead is drawn out of the support, and at least the exposed portion of the internal lead is used in the package using silver. Fixing the light emitting element in the opening of the body and electrically connecting the electrode of the light emitting element to the internal lead; and a solvent so as to cover at least the silver surface of the internal lead in the opening of the support And a step of injecting a solution of a predetermined substance diluted in step (b) and volatilizing the solvent to form a thin film coat. In this method for manufacturing a light emitting device, the predetermined substance is epoxy resin, oxetane resin, urethane resin, acrylate resin, polyimide resin, fluororesin, silsesquioxane derivative, modified silicone resin, acrylic resin, polycarbonate resin, or poly It is desirable that it is at least one of norbornene resins and has a function that hardly allows the sulfur component to permeate. In addition, after the thin film coat is formed, a liquid translucent resin may be injected and cured so as to cover the light emitting element. The translucent resin is preferably a silicone resin, but may be other resins. The ratio of the predetermined substance diluted with the solvent is preferably 50% by weight or less, particularly 30% by weight or less, and more preferably 10% by weight or less based on the solvent.

  A method for manufacturing a light emitting device according to a fourth invention is a method for manufacturing a light emitting device having a light emitting element and a substrate on which the light emitting element is mounted, wherein a wiring pattern is formed, and at least one of the wiring patterns is formed. The part is a step of fixing the light emitting element to a silver-plated substrate and electrically connecting the electrode of the light emitting element to the wiring pattern; and a solution of a predetermined substance diluted with a solvent at least in the wiring pattern. Forming a thin film coat by volatilizing the solvent after the silver plating surface is deposited so as to cover the surface. In the method of manufacturing the light emitting device, the means for attaching the solution of the predetermined substance is spray spray means, ink jet coating means, curtain coating means, dripping means, means for immersing the substrate in the solution of the predetermined substance. One of them. In addition, after the thin film coat is formed, a liquid translucent resin may be injected and cured so as to cover the light emitting element. The translucent resin is preferably a silicone resin, but may be other resins. The ratio of the predetermined substance diluted with the solvent is preferably 50% by weight or less, particularly 30% by weight or less, and more preferably 10% by weight or less based on the solvent. When a resin having a relatively low viscosity diluted with a solvent is used, it can be effectively used for spraying means and the like. Further, when the resin is sprayed in a thin film shape, the amount of volatilization can be reduced, so that a relatively high viscosity resin can be used.

  In the package according to the fifth aspect of the invention, the internal lead is exposed on the inner surface of the opening of the support having an opening for housing the light emitting element, and the external lead electrically connected to the internal lead is drawn out of the support. A package in which silver is used at least for the exposed portion of the internal lead, and covers the surface of the silver of the internal lead except for a connection portion with the light emitting element on the inner surface of the opening of the support. A thin film coat made of a predetermined material is formed.

  A light emitting element mounting substrate according to a sixth aspect of the present invention is a light emitting element mounting substrate on which a wiring pattern is formed, and at least a part of the wiring pattern is subjected to silver plating, and a connection portion with the light emitting element A thin film coat made of a predetermined material is formed so as to cover the surface of the silver plating.

  According to the light emitting device of claim 1, it is possible to prevent sulfidation of the silver surface applied to the internal lead exposed on the inner surface of the opening of the support, and to prevent a decrease in the light output maintenance rate with time. can do.

  According to the light emitting device of claim 2, the light emitting element in the opening of the support of the light emitting device of claim 1 can be protected.

  According to the light emitting device of claim 3, it is possible to prevent sulfidation of the surface of the silver plating applied to the wiring pattern on the substrate for mounting the light emitting element, and to prevent a decrease in the maintenance ratio of the light output with time. it can.

  According to the light emitting device of claim 4, the light emitting element on the substrate for mounting the light emitting element of the light emitting device of claim 3 can be protected.

According to the light-emitting device of claims 5 to 7, in the light-emitting device of claim 1 or 3, by defining a desirable range as H ₂ S permeability, SO ₂ permeability, or film thickness of the thin film coat. In addition, it is possible to give the thin film coat a function that hardly allows the sulfur component to permeate. Further, sulfidation can be prevented with a small amount of resin.

  According to the light emitting device of claim 8, in the light emitting device of claim 1 or 3, by defining a desirable example as a predetermined substance for forming the thin film coat, the thin film coat has a function that hardly allows the sulfur component to pass therethrough. It is possible.

  According to the light emitting device of claim 9, in the light emitting device of claim 2 or 4, the light emitting element can be easily sealed by defining a desirable example of the translucent resin.

  According to the light emitting device of claim 10, in the light emitting device of claim 2 or 4, for example, a white light emitting device can be realized easily and inexpensively by including the wavelength converting substance and the filler in the translucent resin.

  According to the method for manufacturing a light emitting device of claim 11, the light emitting device of claim 1 can be easily realized.

  According to the light emitting device manufacturing method of the twelfth aspect, by defining the predetermined substance for forming the thin film coat, it is possible to easily realize the thin film coat having a function that hardly transmits the sulfur component.

  According to the method for manufacturing a light emitting device of claim 13, the light emitting element can be protected by further forming a translucent resin in the method for manufacturing the light emitting device of claim 11.

  According to the method for manufacturing a light emitting device of claim 14, the light emitting element can be easily sealed by defining a desirable example of the translucent resin in the method for manufacturing the light emitting device of claim 13.

    According to the method for manufacturing a light emitting device of claim 15, the light emitting device of claim 3 can be easily realized.

  According to the method for manufacturing a light emitting device of claim 16, a desired thin film coat can be easily realized by defining a desirable example of means for attaching a solution of a predetermined substance in the method for manufacturing a light emitting device of claim 15. be able to.

  According to the method for manufacturing a light emitting device of claim 17, the light emitting element can be protected by further forming a translucent resin in the method for manufacturing the light emitting device of claim 15.

  According to the method for manufacturing a light emitting device of claim 18, the light emitting element can be easily sealed by defining a desirable example of the translucent resin in the method for manufacturing the light emitting device of claim 17.

    According to the package of claim 19, it is possible to provide a package that can be used for the light emitting device of claim 1.

  According to the substrate for mounting a light emitting element of claim 20, a substrate usable for the light emitting device of claim 3 can be provided.

  Hereinafter, embodiments and examples of the light-emitting device according to the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments and examples. Further, in this description, common reference numerals are assigned to portions common to all the drawings.

<First Embodiment (Package Storage Type Light Emitting Device)>
FIG. 1 is a cross-sectional view schematically showing an example of the structure of a surface-mounted LED device using an LED chip as a light-emitting element, as a first embodiment of the light-emitting device of the present invention. First, the outline | summary of the LED apparatus of FIG. 1 is demonstrated.

  The package 1 includes a resin support 11 and a conductive member made of, for example, a lead frame. The support 11 has an opening (concave portion) for accommodating a light emitting element on the upper surface side, and an internal lead 13a of a lead frame is exposed at a part of the inner surface of the opening, and an external lead 13b electrically connected to the internal lead is provided. The lead is pulled out of the support, and silver (Ag) plating 14 is applied to at least the internal lead 13a. The LED chip 15 is mounted in the opening, and the electrode 15a of the LED chip 15 is electrically connected to the internal lead 13a. Furthermore, a film thickness of 50 μm or less, more preferably 30 μm, in particular, a film obtained by injecting a predetermined resin solution and volatilizing and curing the solvent so as to cover at least the silver plating surface of the inner lead 13 a on the inner surface of the opening, Desirably, a thin film coat 16 for preventing silver plating sulfidation of 10 μm or less is formed. A translucent resin 17 is embedded so as to cover at least the thin film coat 16 and the LED chip 15 in the opening.

  Next, an example of a manufacturing process of the LED device of FIG. 1 will be described. First, the package 1 is insert-formed using a lead frame having a pair of internal leads 13a and a pair of external leads 13b and a heat-resistant resin capable of insert molding. At this time, the pair of internal leads 13a are exposed on the inner surface of the opening of the support 11 made of a resin having an opening for housing the light emitting element, and the pair of external leads 13b are formed to be drawn out. For example, a flat metal member is used for the lead frame, and a silver plate 14 is applied to enhance the light reflectivity of, for example, a copper plate having good thermal conductivity.

  Next, the lower surface of the LED chip 15 made of, for example, an InGaAlN-based nitride semiconductor as a light emitting element is fixed to the opening of the support 11 by die bonding using, for example, a translucent epoxy resin. Next, a wire bonding connection is made between the pair of electrodes 15a formed on the upper surface (light emitting surface side) of the LED chip and the pair of internal leads 13a using conductive wires (for example, gold wires) 18 respectively. Next, a thin film coat 16 having a film thickness of 10 μm or less is formed so as to cover at least the silver-plated surface of the internal lead 13 a in the opening of the support 11. When the thin film coat 16 is formed, for example, an appropriate amount of a solution in which a predetermined modified silicone resin is dissolved in a solvent is injected into the opening, and baking is performed to volatilize the solvent, thereby curing the resin. Alternatively, a thin film coat can be formed only on the silver plating portion using an ink jet or the like. Here, the composition described in Unexamined-Japanese-Patent No. 2004-292779 can be used as an example of a modified silicone resin.

  Next, a translucent resin 17 such as a liquid silicone resin is injected and cured so as to cover at least the thin film coat 16 and the LED chip 15 in the opening of the support 11 and the conductive wire 18, thereby hardening the inside of the opening. Is sealed. Thereafter, the external lead 13b is processed into a desired terminal shape suitable for surface mounting.

  The surface-mount type LED device obtained through the above-described steps is made of a heat-resistant resin that can be insert-molded, and has a support 11 having an opening for housing an LED chip, and an inner surface of the opening of the support 11. An internal lead 13a exposed to the outside and an external lead 13b drawn to the outside of the support. Silver plating 14 is applied to at least the internal lead 13a. The LED chip 15 having the electrode 15a fixed in the opening of the support 11 and electrically connected to the internal lead 13a, and the silver plating surface and the opening inner surface of the internal lead 13a on the inner surface of the opening of the support 11 A thin film coat 16 having a thickness of 10 μm or less cured after a predetermined modified silicone resin is dissolved in a solvent so as to cover the surface of the (reflector). And it has the translucent resin 17 which was inject | poured and hardened so that the thin film coat 16 and LED chip 15 in the opening part of a support body might be coat | covered.

  In the surface mount type LED device having the above-described configuration, the presence of the thin film coat 16 can provide a desired sulfidation preventing effect on the silver plating surface of the internal lead 13a, and decrease the light output maintenance rate with time. It was confirmed that it can be prevented. Moreover, it was confirmed that there exists an antioxidant effect with respect to the inner surface of an opening part. Note that the presence of the thin film coat 16 does not cause deterioration of the translucent resin 17.

  The means for supplying power to the LED chip 15 from the outside of the support 11 to the inner surface of the opening is not limited to the lead frame, and other conductive members may be used. In addition, the translucent resin 17 includes a wavelength conversion substance (for example, a phosphor) that converts light emitted from the LED chip 15 into light having a wavelength (for example, a complementary color) different from the emission color of the LED chip 15, and / Or a filler may be included.

Further, after the thin film coat 16 is formed in the opening, the sealing member may not necessarily be injected, or an inert gas such as an inorganic binder, N ₂ , or Ar may be filled, or May be in a vacuum or close to it.

  Hereinafter, each component in the above-described light emitting device will be described in detail.

  (Support 11) Since the support is provided with a lead electrode on which the LED chip is arranged and an electric current from the outside is supplied to the LED chip, one having heat resistance and insulation is preferably used. Specific examples of such a support include glass epoxy, bismaleimide triazine (hereinafter also referred to as BT resin), ceramics, liquid crystal polymer, and polybutylene terephthalate resin (PBT resin). Moreover, in order to reflect the light from an LED chip efficiently, white pigments, such as a titanium oxide, can be mixed with resin which comprises a board | substrate.

  When the support is molded with resin, the lead electrode for supplying power to the LED chip disposed therein can be formed relatively easily by insert molding or the like. The lead electrode can be formed of a good electrical conductor such as copper and a copper alloy. In this embodiment, the lead electrode is preferably one that efficiently releases heat, and a copper electrode is used. In order to improve the reflectivity of light from the LED chip, the surface of the lead electrode is subjected to silver plating 14, but smooth metal plating such as aluminum or gold can also be performed.

  When the support is constituted by glass epoxy and BT resin, chemical etching is performed to form a desired pattern on BT resin to which copper-clad glass epoxy and copper foil are bonded. Glass epoxy and BT resin in which holes to be side walls are formed by drilling and punching press are bonded to each other with an adhesive. When the support is made of ceramic, a conductive paste containing a refractory metal is printed in a desired pattern on a green sheet that is a raw material before firing the ceramic. A plurality of green sheets are stacked to form a support, and then fired to form a ceramic support. The conductive paste is left as an electrode layer that can be electrically connected to the outside when the resin component jumps during firing.

  (Light-Emitting Element 15) The type of light-emitting element is not particularly limited. For example, a nitride semiconductor such as InN, AlN, GaN, InGaN, AlGaN, or InGaAlN is formed as a light-emitting layer on a substrate by MOCVD or the like. As an example, an n-type contact layer made of n-type GaN, an n-type cladding layer made of n-type AlGaN, and a p-type contact layer made of p-type GaN are sequentially stacked on a sapphire substrate. Use things. The semiconductor structure includes a homostructure having a MIS junction, a PIN junction, a PN junction, etc., a hetero bond, or a double hetero bond. Various emission wavelengths can be selected depending on the semiconductor material and the mixed crystal ratio. Moreover, it can be set as the single quantum well structure or the multiple quantum well structure which formed the semiconductor active layer in the thin film which produces a quantum effect. The active layer may be doped with donor impurities such as Si and Ge and / or acceptor impurities such as Zn and Mg. The emission wavelength of the light-emitting element can be changed from the ultraviolet region to red by changing the In content of InGaN in the active layer or changing the type of impurities doped in the active layer.

In general, a nitride semiconductor (In _X Ga _Y Al _1-XY N, 0 ≦ X, 0 ≦ Y, 0 ≦ X + Y ≦ 1) is difficult to grow a crystal and is formed on an insulating sapphire substrate. In order to supply power to the nitride semiconductor formed on the sapphire substrate, the positive electrode (p electrode) and the negative electrode (n electrode) must be formed on the same surface side (semiconductor laminated surface side), and ohmic contact is made. In order to inject current efficiently, a gold thin film or the like is used as a translucent electrode. Although such an electrode is made of a metal although it is a thin film and has translucency, light generated in the active layer of the LED chip using a nitride semiconductor is partially reflected.

  Such an LED chip can be mounted on a support using a die-bonding device. Moreover, it can electrically connect with the electrode provided on the LED chip, and a gold wire.

  As the light emitting element, a blue light emitting element having an emission peak wavelength near 460 nm, a blue-violet light emitting element having an emission peak wavelength near 410 nm, an ultraviolet light emitting element having an emission peak wavelength near 365 nm, or the like is used. be able to.

  When realizing a white light emitting device, for example, a blue light emitting element and a YAG phosphor (a rare earth aluminate mainly activated by a lanthanoid element such as Ce) as a fluorescent material contained in the light-transmitting coating member By using a combination with a salt phosphor, white light emission can be obtained by mixing colors of light emitted from the light emitting element and light emitted from the YAG phosphor.

(Conductive Wire 18) The conductive wire is required to have good ohmic properties, mechanical connectivity, electrical conductivity, and thermal conductivity with the electrode of the light emitting element. The thermal conductivity, preferably ^{0.01cal / (S) (cm 2} ) (℃ / cm) or higher, more preferably is ^{0.5cal / (S) (cm 2} ) (℃ / cm) or more. In consideration of workability and the like, the diameter of the conductive wire is preferably 10 μm or more and 45 μm or less. Specific examples of such conductive wires include wires using metals such as gold, copper, platinum, and aluminum, and alloys thereof. Such a conductive wire can be easily bonded and connected between each light emitting element and the internal terminal by a wire bonding apparatus.

(Thin Film Coat 16) The thin film coat only needs to have a function that hardly allows the sulfur component to permeate. For example, H ₂ S permeability is 100 × 10 ⁻⁹ (ml · cm / sec · cm ² · cmHg) or less, Alternatively, the SO ₂ permeability is 150 × 10 ⁻⁹ (ml · cm / sec · cm ² · cmHg) or less, and the film thickness is 50 μm or less, preferably 10 μm or less. The thin film coat 16 can be formed by injecting an appropriate amount of a solution obtained by diluting a predetermined substance with a solvent into the opening, and then volatilizing the solvent. Here, the predetermined substance is at least one of epoxy resin, oxetane resin, urethane resin, acrylate resin, polyimide resin, fluororesin, silsesquioxane derivative, modified silicone resin, acrylic resin, polycarbonate resin, or polynorbornene resin. It is a seed. The ratio of the predetermined substance diluted with the solvent is preferably 50% by weight or less, particularly preferably 30% by weight or less, and more preferably 10% by weight or less based on the solvent. The solvent to be volatilized can be recovered and reused.

  (Translucent resin 17) The translucent sealing material is provided in the opening of the support, efficiently transmits light from the LED chip to the outside, and from an external force, dust, etc., such as an LED chip or a gold wire. Is to protect. Examples of such a light-transmitting sealing material include thermosetting resins such as silicone resins, modified silicone resins, epoxy resins, acrylate resins, urethane resins, polyimide resins, acrylic resins, polycarbonate resins, polynorbornene resins, and the like. At least one selected from thermoplastic resins can be used.

  The translucent resin may contain a wavelength conversion substance and / or an inorganic filler. At this time, it is desirable that the thermal expansion coefficient approximates that of the substrate, the package, and the LED chip to prevent the translucent resin from being separated from the package. For example, by using an InGaN-based blue light-emitting LED chip as a light-emitting element and a YAG phosphor as a wavelength conversion material, a white light-emitting LED device can be easily and inexpensively realized.

<Second Embodiment (Package Storage Type Light Emitting Device with Step)>
FIG. 2 is a cross-sectional view schematically showing an example of the structure of the surface-mount LED device according to the second embodiment. The LED device of FIG. 2 is formed with a stepped portion 11a in which a part (for example, the central portion) of the inner bottom surface of the opening of the package 1a is lower than the LED device of the first embodiment described above with reference to FIG. The LED chip 15 is mounted face up on the inner bottom surface of the opening. The internal lead 13a is different in that it is exposed on the upper surface of the stepped portion, and the others are the same. It is desirable that the side wall surface of the step portion is also subjected to silver plating. The internal lead 13a and the electrode 15a on the upper surface of the LED chip are bonded and connected by a conductive wire 18. A thin film coat 16 having a film thickness of, for example, 10 μm or less is formed so as to cover at least a part of the inner surface of the opening. Further, a silicone resin 17 is embedded in the opening so as to cover the internal leads 13 a, the LED chip 15, and the conductive wires 18.

  In the LED device of FIG. 2 having the above-described configuration, basically the same effect as the LED device of FIG. 1 described above with reference to FIG. 1 can be obtained, and the mounting position of the LED chip is the position of wire bonding (2nd bonding). Since it has a lower cup structure, silver plating can be coated before mounting the LED chip. Accordingly, the coating resin is not coated on the chip upper surface electrode (1st bonding position of the wire) and the 2nd bonding position, and the interface with the light-transmitting resin for sealing does not exist in the gold wire portion of the bonding wire, which is a different resin. Since the gold wire breakage does not occur at the physical property interface, the reliability is improved.

<Third Embodiment (Board Mount Type Light Emitting Device)>
FIG. 3 is a cross-sectional view schematically showing an example of the structure of a surface-mounted LED device using an LED chip as a light-emitting element, as a third embodiment of the light-emitting device of the present invention. The LED device of FIG. 3 is mainly different from the LED device of the first embodiment described above with reference to FIG. 1 in that a light emitting element mounting substrate 30 is used instead of the package 1. .

  The substrate 30 for mounting a light emitting element is provided with a wiring pattern 32 on the upper surface of a flat plate type substrate (for example, printed wiring board) 31 made of glass epoxy, ceramics, etc., and at least a part (for example, a front end portion) of the wiring pattern 32. For example, silver plating 33 is applied, and a thin film coat 34 made of a predetermined material is formed so as to cover the surface of the silver plating 33. The LED chip 35 is mounted face-up on the substrate 31, for example, and the electrodes of the LED chip 35 are electrically connected to the wiring pattern 32 by, for example, bonding wires 36. After the LED chip 35 is mounted, the LED chip 35 is further sealed with a translucent resin (for example, silicone resin) 37 so as to cover the LED chip 35. The wiring pattern 32 is drawn out to the side surface of the substrate and serves as an external terminal.

  The thin film coat 34 is the same as the thin film coat 16 described in the first embodiment, and has a function of hardly allowing the sulfur component to pass therethrough. The thin film coat 34 can be formed by volatilizing the solvent after adhering a solution obtained by diluting a predetermined substance with a solvent so as to cover at least the silver plating surface of the wiring pattern. As the means for attaching the solution of the predetermined substance, any of spray spraying means, inkjet coating means, curtain coating means, dropping means, and means for immersing the substrate in the predetermined substance solution can be used. The proportion of the predetermined substance diluted with the solvent is preferably 50% by weight or less, particularly 30% by weight or less, and more preferably 10% by weight or less based on the solvent. When a relatively low viscosity solution obtained by diluting a predetermined resin with a solvent is used, it can be effectively used for spraying means. Further, when the resin is sprayed in a thin film, the amount of volatilization can be reduced, so that a relatively high viscosity resin can be used.

<Fourth embodiment (substrate mounting type, light emitting device with reflector)>
FIG. 4: is sectional drawing which shows typically an example of the structure of the surface-mount type LED device with a reflector as 4th Embodiment of the light-emitting device of this invention. The LED device of FIG. 4 is mounted and fixed with a reflector 40 so as to surround the LED chip 35 on the substrate 30 as compared with the LED device of the third embodiment described above with reference to FIG. The point is mainly different.

  The reflector 40 has an opening at the center of a flat substrate, and the tapered side wall surface inside the opening is silver-plated 33 to be a reflecting surface. A thin film coat 34 made of a predetermined material is formed so as to cover at least the surface of the silver plating 33 on the wiring pattern 32 and the reflection surface of the reflector 40 with the LED chip 35 face-up mounted on the substrate 31. Has been. The thin film coat 34 that covers the reflecting surface of the reflector 40 may be formed before the reflector 40 is mounted on the substrate 31 and may not be formed after the reflector 40 is mounted on the substrate 31. Further, the LED chip 35 is covered with a translucent resin 37 so as to cover the inside of the opening of the reflector 40.

  Also in the light emitting device with the substrate mounting type and the reflector according to the fourth embodiment described above, the effect due to the presence of the thin film coat 34 is obtained as in the case of the light emitting device of the package storage type according to the first embodiment described above. .

Specific examples will be described in detail below, but the present invention is not limited to these examples.
[Examples 1 and 2] In Examples 1 and 2, an LED chip having a light emitting layer with a nitride semiconductor capable of emitting blue (470 nm) on the bottom surface of the opening of the package 1 as shown in FIG. Arranged by bonding. In the LED chip, a buffer layer made of gallium nitride, an n-type contact / cladding layer made of GaN, a p-type cladding layer made of GaAlN, and a p-type contact layer made of GaN are stacked on a sapphire substrate. An InGaN layer having a single quantum well structure is formed between the n-type contact layer and the p-type cladding layer. In order to form positive and negative electrodes from the semiconductor layer formed on the sapphire substrate, a part of the nitride semiconductor is etched to expose the n-type contact layer. A gold thin film is formed as an ohmic electrode on the p-type contact layer.

  The package 1 was formed by placing a pre-formed lead electrode in a mold and injecting a polyamide resin. A part of the lead electrode (internal lead 13a) is exposed on the inner bottom surface of the opening of the package, and the internal lead 13a is silver-plated. The inner bottom surface of the opening of the package is a flat surface (smooth surface) that can reflect most of the light from the LED chip incident from a certain direction, such as a mirror surface, in a specific direction. The light in the longitudinal direction emitted from the LED chip 15 arranged on such a plane can be efficiently emitted to the front surface. Therefore, the silver-plated surface of the internal lead 13a, the bottom surface and the side surface in the opening can efficiently reflect the light from the LED chip 15.

  The LED chip 15 was mounted by die bonding using a translucent epoxy resin in the opening of the package 1. Each electrode 15a of the LED chip 15 and the internal lead 13a are wire-bonded using a gold wire 18 and are electrically connected.

  Further, a thin film coat 16 having a film thickness of 10 μm or less was formed so as to cover at least the surface of the reflector made of silver plating of the internal lead 13a and the inner surface of the opening in the opening of the package. At this time, a solution in which a predetermined resin was dissolved in a solvent was poured into the opening, the solvent was volatilized by baking, and the resin was cured to form the thin film coat 16.

  Next, a liquid translucent resin 17 was injected and cured so as to cover at least the thin film coat 16 and the LED chip 15 in the opening of the support 11 and the conductive wire 18. A silicone resin is used as such a translucent resin for sealing.

  Thereafter, the external lead 13b is processed into a desired terminal shape suitable for surface mounting. For example, the external terminal 13c is formed by bending from the side surface of the support body to the bottom surface side along the bottom surface of the support body. Solder connection when mounting.

The surface-mount type LED device obtained through the above-described steps can obtain the effects described above in the first embodiment. Concretely, as a result of conducting a sulfidation test with a sulfidation test apparatus on the processed products 1 and 2 obtained in Examples 1 and 2 with different processing methods for forming a thin film coat, the confirmed effect was compared with a comparative example (thin film coat). Is not formed). As a processing method for forming the thin film coat, acetone or PGMEA (propylene glycol monoethyl ether acetate) was used as a solvent. And the solution which diluted the said resin with the solvent is dripped in an opening part from a dispenser, a solvent is volatilized by hardening (for example, 120 degreeC for 1 hour), a thin film coat is formed, and it hardens (at 150 degreeC at maximum for 1 hour). . Under the present circumstances, the sulfuration test was done with the sulfuration test apparatus about the processed goods 1-2 obtained by Example 1-2 obtained by varying the kind and density | concentration of a solution.
(Treatment method) Solvent Resin concentration Example 1 (Treatment product 1) Acetone 9.9 g 0.1 g 1%
Example 2 (treated product 2) Acetone 9.95 g 0.05 g 0.5%
(Test conditions) Explosion for 96 hours in an atmosphere of 40 ° C., 80% RH, H ₂ S flow rate of 15 ppm

(Test result) Thin film coating Light output extraction efficiency Low rate (Comparative example 1) None 84% of initial value 16%
Example 1 (treated product 1) Yes 94% of initial value 6%
Example 2 (Processed product 2) Yes 93% of initial value 7%

According to the processed products 1 and 2, it is estimated that the LED life is 2.6 times longer than that of the comparative example.
[Example 3]

In the same manner as in Example 1, a solution obtained by diluting the resin with a solvent was dropped from the dispenser into the opening, and then left in the atmosphere under the condition that the resin did not cure (25 ° C., 8 hours) to volatilize the solvent. After confirming that the coated resin is not cured, a translucent silicone resin is dropped, and the translucent silicone resin and the coat resin are cured simultaneously, and then, in the same manner as in Examples 1 and 2, As a result of conducting a sulfuration test with a test apparatus, the same effects as in Examples 1 and 2 were obtained.

(Treatment method) Solvent Resin concentration Example 3 (Treatment product 3) Acetone 9.9 g 0.1 g 1%
(Test result) Thin film coating Light output extraction efficiency Low rate (Comparative Example 1) None 84% of initial value 16%
Example 3 (treated product 3) Simultaneous curing with sealing resin 94% of initial value 6%
[Examples 4 to 7] In Examples 4 to 7, an LED chip having a light emitting layer with a nitride semiconductor capable of emitting blue (470 nm) is formed on the bottom surface of the opening of the package 1 as shown in FIG. It is arranged by bonding and mounted face up. In this case, the internal lead is exposed on the upper surface of the stepped portion on the inner bottom surface of the opening. The silver plating is applied to at least the surface of the inner lead of the lead frame, and more preferably to the inner surface of the opening. The internal lead and the electrode on the upper surface of the LED chip are bonded and connected by a conductive wire. Then, a thin film coat 16 for preventing silver plating sulfidation having a thickness of, for example, 10 μm or less, in which a predetermined resin is injected and cured so as to cover at least a part of the inner surface of the opening and the silver plating surface of the internal lead 13a. Is formed. The silicone resin 18 is embedded so as to cover the internal lead 13a, the LED chip 15, and the conductive wire 18 in the opening.

The surface-mounted LED device obtained through the above-described steps can achieve the same effects as the surface-mounted LED device of the second embodiment described above with reference to FIG. In addition, the predetermined resin used for the thin film coat of Examples 1-7 uses the silicone resin of Example 45 of the gazette shown in the embodiment. Further, as a result of conducting a sulfuration test with a sulfuration test apparatus on the processed products obtained by different examples of the thin film coat formation processing method, the same effects as in Examples 1 to 3 were obtained.
(Treatment method) Solvent Resin concentration Example 4 (Treatment product 1) Acetone 9.9 g 0.1 g 1%
Example 5 (treated product 2) Acetone 9.95 g 0.05 g 0.5%
Example 6 (treated product 3) PGMEA 9.9 g 0.1 g 1%
Example 7 (treated product 4) PGMEA 9.95 g 0.05 g 0.5%
(Test conditions) Explosion for 96 hours in an atmosphere of 40 ° C., 80% RH, H ₂ S flow rate of 15 ppm

(Test result) Thin film coating Light output extraction efficiency Low rate (Comparative Example 2) None 83.8% of initial value 16.2%
Example 4 (treated product 4) Yes 98.1% of initial value 1.9%
Example 5 (Processed product 5) Yes 97.7% of initial value 2.3%
Example 6 (treated product 6) Yes 98.9% of initial value 1.1%
Example 7 (Processed product 7) Yes 99.0% of initial value 1.0%
According to the processed goods 4-7, it is estimated that LED lifetime extends 7 to 16 times of a comparative example.

  The light emitting device and the manufacturing method thereof of the present invention are applied to various indicators, displays, writing light sources for optical printers, light sources for backlights, and the like.

Sectional drawing which shows typically an example of the structure of the surface-mount type LED device which concerns on 1st Embodiment of the light-emitting device of this invention. Sectional drawing which shows typically an example of the structure of the surface mount type LED device which concerns on 2nd Embodiment of the light-emitting device of this invention. Sectional drawing which shows typically an example of the structure of the surface mount type LED device which concerns on 3rd Embodiment of the light-emitting device of this invention. Sectional drawing which shows typically an example of the structure of the surface mount type LED device which concerns on 4th Embodiment of the light-emitting device of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Package, 11 ... Resin support body, 13a ... Internal lead, 13b ... External lead, 14 ... Silver plating, 15 ... LED chip, 15a ... Electrode of LED chip, 16 ... Thin film coat, 17 ... Translucent resin , 18 ... conductive wire.

Claims (20)

An internal lead is exposed on the inner surface of the opening of the support having an opening for accommodating the light emitting element, and an external lead electrically connected to the internal lead is drawn out of the support, and at least on the exposed portion of the internal lead A package using silver,
A thin film coat made of a predetermined substance formed so as to cover at least the silver surface of the internal lead on the inner surface of the opening of the support;
A light emitting device mounted in the opening of the support and having an electrode electrically connected to the internal lead;
A light-emitting device comprising: The light emitting device according to claim 1, further comprising a translucent resin that seals at least the light emitting element in the opening of the support. A wiring pattern is formed, and at least a part of the wiring pattern is a silver-plated substrate for mounting a light emitting element,
A thin film coat made of a predetermined material formed to cover the surface of the silver plating;
A light emitting device comprising: a light emitting element mounted on the substrate and having an electrode electrically connected to the wiring pattern. The light emitting device according to claim 3, further comprising a translucent resin that seals at least the light emitting element. The light-emitting device according to claim 1, wherein the thin film coat has a H ₂ S permeability of 100 × 10 ⁻⁹ (ml · cm / sec · cm ² · cmHg) or less. The light-emitting device according to claim 1, wherein the thin film coat has an SO ₂ permeability of 150 × 10 ⁻⁹ (ml · cm / sec · cm ² · cmHg) or less. The light-emitting device according to claim 1, wherein the thin film coat has a film thickness of 50 μm or less. The predetermined substance is an epoxy resin diluted with a solvent, an oxetane resin, a urethane resin, an acrylate resin, a polyimide resin, a fluorine resin, a silsesquioxane derivative, a modified silicone resin, an acrylic resin, a polycarbonate resin, or a polynorbornene resin. The light emitting device according to claim 1 or 3, wherein at least one solution is used and the solvent is volatilized. The light-emitting device according to claim 2, wherein the translucent resin is a silicone resin. The light-emitting device according to claim 2, wherein the translucent resin contains a wavelength conversion substance and / or an inorganic filler. A method of manufacturing a light emitting device having a light emitting element and a package on which the light emitting element is mounted,
An internal lead is exposed on the inner surface of the opening of the support having an opening for accommodating the light emitting element, and an external lead electrically connected to the internal lead is drawn out of the support, and at least on an exposed portion of the internal lead. Using a package in which silver is used, fixing a light emitting element in the opening of the support, and electrically connecting an electrode of the light emitting element to the internal lead;
Forming a thin film coat by volatilizing the solvent after injecting a solution of a predetermined substance diluted with a solvent so as to cover at least the silver surface of the internal lead in the opening of the support;
A method of manufacturing a light emitting device, comprising: The predetermined substance is at least one of epoxy resin, oxetane resin, urethane resin, acrylate resin, polyimide resin, fluorine resin, silsesquioxane derivative, modified silicone resin, acrylic resin, polycarbonate resin, or polynorbornene resin. The method for manufacturing a light emitting device according to claim 11, wherein: The method of manufacturing a light emitting device according to claim 11, further comprising a step of injecting and curing a liquid translucent resin so as to cover the light emitting element after forming the thin film coat. The method of manufacturing a light emitting device according to claim 13, wherein the translucent resin is a silicone resin. A method of manufacturing a light emitting device having a light emitting element and a substrate on which the light emitting element is mounted,
Forming a wiring pattern, fixing a light emitting element to a silver plated substrate at least a part of the wiring pattern, and electrically connecting an electrode of the light emitting element to the wiring pattern;
Forming a thin film coat by volatilizing the solvent after attaching a solution of a predetermined substance diluted with a solvent so as to cover at least the surface of the silver plating of the wiring pattern;
A method of manufacturing a light emitting device, comprising: The means for adhering the solution of the predetermined substance is any one of spray spraying means, ink jet coating means, curtain coating means, dripping means, and means for immersing the substrate in the solution of the predetermined substance. A method for manufacturing a light emitting device according to claim 15. 16. The method for manufacturing a light-emitting device according to claim 15, further comprising a step of sealing with a light-transmitting resin so as to cover the light-emitting element after forming the thin film coat. The method of manufacturing a light emitting device according to claim 17, wherein the translucent resin is a silicone resin. An internal lead is exposed on the inner surface of the opening of the support having an opening for accommodating the light emitting element, and an external lead electrically connected to the internal lead is drawn out of the support, and at least on the exposed portion of the internal lead A package using silver,
A thin film coat made of a predetermined substance formed so as to cover the surface of the silver of the internal lead is formed on the inner surface of the opening of the support, except for a connection portion with the light emitting element. And package. A wiring pattern is formed, and at least a part of the wiring pattern is a substrate for mounting a light emitting element on which silver plating is applied,
A substrate for mounting a light-emitting element, wherein a thin film coat made of a predetermined material is formed so as to cover the surface of the silver plating except for a connection portion with the light-emitting element.

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