JP6051820B2 - Silver sulfide prevention material, method of forming silver sulfide prevention film, and method of manufacturing light emitting device - Google Patents

Description

  The present invention relates to a silver sulfide prevention material, and more particularly to a silver sulfide prevention material for preventing discoloration due to sulfuration of silver plating used in a light emitting device or the like. The present invention also relates to a method for forming a silver sulfide prevention film using a silver sulfide prevention material and a method for manufacturing a light emitting device.

  In recent years, the demand for light-emitting diodes (LEDs) as a light source that replaces fluorescent lamps and incandescent lamps is rapidly increasing. A light-emitting device including a light-emitting element such as a light-emitting diode is used in applications such as lighting equipment and automobile lights. In such a light-emitting device, light extraction efficiency is improved by providing a light reflection film made of silver plating. For example, in an LED package including a lead frame such as a copper plating substrate, the reflectance is improved by providing a silver plating layer on the copper plating layer (see, for example, Patent Document 1 below).

JP 2009-239116 A

  In the LED package, the light emitting element, the light reflection film, and the like are usually protected by sealing with a transparent resin. However, when the light-emitting device is used outdoors, there is a problem that hydrogen sulfide, sulfurous acid gas, and the like in the environment permeate the resin and sulfidize the silver plating, and the light reflectance of the silver plating decreases due to discoloration. Recently, the amount of heat generated by the LED increases as the output of the LED increases, and the sulfidation of the silver plating tends to be further accelerated as the temperature increases.

  The present invention has been made in view of the above circumstances, and a silver sulfide prevention material capable of sufficiently suppressing silver sulfidation, a method for forming a silver sulfide prevention film using the same, and a light emitting device excellent in sulfide resistance. It aims at providing the manufacturing method of.

  In order to solve the above-mentioned problems, the present inventors diligently studied. As a result, a silver sulfidation-preventing material containing two or more kinds of clay was applied on the silver plating layer, and this coating film was dried. The present inventors have found that a silver sulfide prevention film capable of highly suppressing plating sulfidation can be formed and completed the present invention.

  That is, the present invention provides a silver sulfide preventive material containing two or more types of clay.

  According to the silver sulfide preventive material of the present invention, a silver sulfide preventive film capable of sufficiently suppressing silver sulfide can be formed by applying to the surface of a metal layer containing silver and drying.

  The present inventors consider the reason why the silver sulfide preventive material of the present invention exhibits the above effect as follows. When the silver sulfide preventive material contains different types of clay, a laminated structure with fewer gaps is formed in the film formation by applying and drying the silver sulfide preventive material than when only one kind of clay is included, and the gas barrier property is improved. It is thought that it improved.

  The silver sulfide preventive material of the present invention preferably contains two or more kinds of clays having different aspect ratios. In this case, the gas path can be lengthened by filling the clay having a large aspect ratio with clay having a small aspect ratio.

  From the viewpoint of achieving both high-level suppression of silver sulfidation and suppression of silver discoloration in a high-temperature, high-humidity environment, the silver sulfidation inhibitor is composed of clay having an aspect ratio of 1 to 80 and an aspect ratio of 81 to 81. It is preferable to contain 1000 clays.

  The present invention also includes a coating step of coating the silver sulfide prevention material according to the present invention on the surface of the metal layer containing silver to form a coating film of the silver sulfide prevention material, and a drying step of drying the coating film. A method for forming a silver sulfide preventive film is provided.

  According to the method for forming a silver sulfide prevention film of the present invention, a silver sulfide prevention film capable of sufficiently suppressing silver sulfidation can be formed by using the silver sulfide prevention material according to the present invention.

  The metal layer is preferably a silver plating layer. In this case, it can prevent that the light reflectance of a silver plating layer falls by sulfuration.

  From the viewpoint of more reliably preventing silver sulfidation, the thickness of the coated film after drying is preferably 0.005 μm or more.

  The present invention is also a method for manufacturing a light emitting device comprising a substrate having a silver plating layer and a light emitting element mounted on the substrate, wherein the silver sulfide prevention material according to the present invention is formed on the surface of the silver plating layer. The manufacturing method of a light-emitting device provided with the application | coating process which forms a coating film of silver sulfide prevention material by apply | coating and the drying process which dries a coating film is provided.

  According to the method for manufacturing a light-emitting device of the present invention, a silver sulfide prevention film capable of sufficiently suppressing silver sulfidation can be formed on the surface of the silver plating layer, thereby producing a light-emitting device having excellent sulfidation resistance. Can be manufactured.

  From the viewpoint of more reliably preventing silver sulfidation, the thickness of the coated film after drying is preferably 0.005 μm or more.

  ADVANTAGE OF THE INVENTION According to this invention, the silver sulfide prevention material which can fully suppress silver sulfidation, the formation method of the silver sulfide prevention film using the same, and the manufacturing method of the light-emitting device excellent in sulfide resistance can be provided. .

It is sectional drawing of a light-emitting device. It is a top view of the light-emitting device shown in FIG. 3 is a flowchart illustrating a method for manufacturing the light emitting device according to the first embodiment. It is sectional drawing of the light-emitting device after the application | coating process of the silver sulfide prevention material which concerns on embodiment. It is sectional drawing of the light-emitting device after a drying process. It is sectional drawing of the light-emitting device after a transparent sealing resin filling process. It is a conceptual diagram for demonstrating the structure of the silver sulfide prevention film formed from the silver sulfide prevention material which concerns on embodiment. It is the flowchart which showed the manufacturing method of the light-emitting device which concerns on 2nd Embodiment. It is sectional drawing of the light-emitting device manufactured with the manufacturing method of FIG. It is the flowchart which showed the manufacturing method of the light-emitting device which concerns on 3rd Embodiment. It is sectional drawing of the light-emitting device manufactured with the manufacturing method of FIG.

  The silver sulfide prevention material according to this embodiment includes two or more types of clay. This silver sulfide preventive material can contain a solvent for dispersing clay. According to the silver sulfide preventive material of this embodiment, a silver sulfide preventive film that can sufficiently suppress silver sulfide can be formed by applying to the surface of a metal layer containing silver and drying. An example of the metal layer is a silver plating layer.

  As clay, it can be used in combination of two or more of natural clay and synthetic clay and their modified products.

  Examples of the natural clay include kaolin, talc-pyrophyllite, smectite, vermiculite, mica (mica), brittle mica, and chlorite. Typical species include lizardite, amicite, chrysotile, kaolinite, dickite, halloysite, talc, pyrophyllite, saponite, hectorite, montmorillonite, beidellite, trioctahedral vermiculite, octahedral vermiculite, phlogopite. , Biotite, lepidrite, illite, muscovite, paragonite, clintonite, margarite, clinochlore, chamosite, nimite, dombasite, kukeite, sudite.

  Examples of commercially available products include Kunipia (Kunimine Kogyo Co., Ltd., trade name, Kunipia F), and wet pulverized mica (Yamaguchi Mica, Y series, SA series).

  Examples of the synthetic clay include fluorine phlogopite, potassium tetrasilicon mica, sodium tetrasilicon mica, Na teniolite, Li teniolite, montmorillonite, saponite, hectorite, and stevensite.

  Commercially available products include Micromica, Somasifu (Coop Chemical Co., Ltd., trade name, MEB-3), Lucentite (Coop Chemical Co., Ltd., trade name, SWN), Swellable Micasol (Topy Industries, NTS) -10, NTS-5).

  As a modified product of synthetic clay, for example, Somasifu (manufactured by Co-op Chemical Co., Ltd., trade name, MAE) and Lucentite (manufactured by Co-op Chemical Co., Ltd., trade name, SPN) can be given as commercial products.

  The silver sulfide preventive material of this embodiment preferably contains two or more types of clay having different aspect ratios. In this case, the gas path can be lengthened by filling the clay having a large aspect ratio with clay having a small aspect ratio.

  The aspect ratio means the average long side length / average thickness of the crystal.

  From the viewpoint of achieving both high-level suppression of silver sulfidation and suppression of silver discoloration in a high-temperature, high-humidity environment, the silver sulfidation inhibitor is composed of clay having an aspect ratio of 1 to 80 and an aspect ratio of 81 to 81. It is preferable to contain 1000 clays.

  In terms of improving gas barrier properties, the silver sulfide prevention material of the present embodiment is a natural clay having a large aspect ratio such as montmorillonite and mica, and a natural or synthetic clay having a small aspect ratio such as stevensite, saponite and hectorite. It is preferable to contain. In the silver sulfide preventive material of this embodiment, the mass ratio of the clay having a large aspect ratio and the clay having a small aspect ratio is preferably 1/99 to 99/1, and 10/90 to 99/1. More preferably, it is more preferably 25/75 to 99/1.

  Examples of the solvent include water and water-soluble liquid.

  As water, for example, ultrapure water is used. Ultrapure water is water that contains a very small amount of ionic impurities, and has an electrical resistivity (specific resistance, MΩ · cm) (JIS K0552) as an index, and has a theoretical value of 15 MΩ · cm or more at 25 ° C., Preferably, water of 18 MΩ · cm or more can be used.

  Examples of the water-soluble liquid include polar solvents such as alcohol, specifically, ethanol, methanol, isopropyl alcohol, n-propyl alcohol, dioxane, acetone, acetonitrile, diethylamine, n-butyl alcohol, isobutyl alcohol, t-butyl alcohol, pyridine, N, N-dimethylformamide, dimethyl sulfoxide, sulfolane, N-methylpyrrolidone, propylene carbonate, γ-butyrolactone, formamide, allyl alcohol, acrylic acid, acetic acid, ethylene glycol, propylene glycol, glycerin, methacryl Liquids such as acid, butyric acid, trimethylamine, triethylamine, aqueous ammonia, and diethyl sulfite can be employed. A water-soluble liquid refers to a liquid that maintains a uniform appearance even after the flow has subsided when gently mixed with pure water of the same volume at a temperature of 20 ° C. at 1 atm. A water-soluble liquid can be used individually by 1 type or in mixture of 2 or more types.

  The silver sulfide preventive material of this embodiment is preferably used so that the film thickness after drying is 0.005 μm or more from the viewpoint of preventing silver sulfide. For example, in order to prevent sulfidation of the silver plating layer, it is preferable to apply and dry a silver sulfidation preventing material on the silver plating layer so that a clay film having a film thickness of 0.005 μm or more is formed.

  Various additives can be added to the silver sulfide preventing material of the present embodiment as long as the effects of the present invention are not impaired. Examples of the additive include a binder and a surfactant.

  Examples of the method for preparing the silver sulfide preventive material of the present embodiment include a method in which clay and, if necessary, the above additives are added to a solvent such as water and dispersed and stirred. Stirring can be performed using, for example, a rotation / revolution mixer, a stirrer, ultrasonic waves, a shaker, or the like.

  According to the silver sulfidation preventive material of this embodiment, it is made of clay contained in the silver sulfidation preventive material on the surface of the metal layer by applying and drying on the surface of the metal layer containing silver, and sulfiding silver. A silver sulfide prevention film that can be sufficiently suppressed can be formed.

  Next, a preferred embodiment of a method for forming a silver sulfide prevention film using the silver sulfide prevention material of the present embodiment and a method for manufacturing a light emitting element will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

[First Embodiment]
First, before explaining the manufacturing method of the light emitting device according to the first embodiment, the configuration of the light emitting device manufactured by the manufacturing method of the light emitting device according to the first embodiment with reference to FIG. 1 and FIG. Will be described.

  FIG. 1 is a cross-sectional view of the light emitting device. FIG. 2 is a plan view of the light-emitting device shown in FIG. As shown in FIGS. 1 and 2, the light emitting device 1 according to the embodiment is generally classified as a “surface mount type”. The light emitting device 1 includes a substrate 10, a blue LED 30 bonded to the surface of the substrate 10 as a light emitting element, a reflector 20 provided on the surface of the substrate 10 so as to surround the blue LED 30, and the reflector 20 filled with blue. And a transparent sealing resin 40 that seals the LED 30. In addition, illustration of the transparent sealing resin 40 is abbreviate | omitted in FIG.

  In the substrate 10, a copper plating plate 14 is wired on the surface of an insulating base 12, and a silver plating layer 16 is formed on the surface of the copper plating plate 14. The silver plating layer 16 is an electrode that is disposed on the surface of the substrate 10 and is electrically connected to the blue LED 30. The silver plating layer 16 may have any composition as long as it is a plating layer containing silver. For example, the silver plating layer 16 may be formed by plating only silver, or the silver plating layer 16 may be formed by plating nickel and silver in this order. The copper plating plate 14 and the silver plating layer 16 are insulated on the anode side and the cathode side. The insulation between the copper plating plate 14 and the silver plating layer 16 on the anode side and the copper plating plate 14 and the silver plating layer 16 on the cathode side is, for example, the copper plating plate 14 and the silver plating layer 16 on the anode side and the cathode side. The copper plating plate 14 and the silver plating layer 16 can be separated from each other, and an insulating layer such as a resin and ceramic can be appropriately inserted between them.

  The blue LED 30 is die-bonded to any one of the silver plating layer 16 on the anode side and the cathode side, and is electrically connected to the silver plating layer 16 through the die bonding material 32. The blue LED 30 is wire-bonded to the silver plating layer 16 on either the anode side or the cathode side, and is electrically connected to the silver plating layer 16 via the bonding wire 34.

  The reflector 20 fills a transparent sealing resin 40 for sealing the blue LED 30 and reflects light emitted from the blue LED 30 to the surface side of the light emitting device 1. The reflector 20 is erected from the surface of the substrate 10 so as to surround the blue LED 30. That is, the reflector 20 is formed with an inner space 22 that rises from the surface 10a of the substrate 10 so as to surround the blue LED 30 and accommodates the blue LED 30 inside, and has an inner circumference formed in a circle in plan view (see FIG. 2). A surface 20a, a top surface 20b adjacent to the inner peripheral surface 20a and positioned outside the inner space 22 and extending from the front edge of the inner peripheral surface 20a toward the opposite side of the inner space 22, and the outer surface of the top surface 20b An outer peripheral surface 20c that falls from the edge to the surface 10a of the substrate 10 and is formed in a rectangular shape in plan view (see FIG. 2). The shapes of the inner peripheral surface 20a and the outer peripheral surface 20c are not particularly limited, but from the viewpoint of improving the illuminance of the light emitting device 1, the inner peripheral surface 20a has a truncated cone shape (funnel shape) whose diameter increases as the distance from the substrate 10 increases. The outer peripheral surface 20 c is preferably formed in a quadrangular shape perpendicular to the substrate 10 from the viewpoint of improving the degree of integration of the light emitting device 1. In the drawing, as an example of forming the inner peripheral surface 20a, the lower part located on the substrate 10 side is perpendicular to the substrate 10, and the upper part located on the opposite side of the substrate 10 is separated from the substrate 10. An enlarged diameter is shown.

  The reflector 20 is made of a cured product of a thermosetting resin composition containing a white pigment. From the viewpoint of ease of forming the reflector 20, the thermosetting resin composition is preferably one that can be pressure-molded at room temperature (25 ° C.) before thermosetting.

  As the thermosetting resin contained in the thermosetting resin composition, various resins such as an epoxy resin, a silicone resin, a urethane resin, and a cyanate resin can be used. In particular, an epoxy resin is preferable because of its excellent adhesion to various materials.

  As the white pigment, alumina, magnesium oxide, antimony oxide, titanium oxide, or zirconium oxide can be used. Among these, titanium oxide is preferable from the viewpoint of light reflectivity. Inorganic hollow particles may be used as the white pigment. Specific examples of the inorganic hollow particles include sodium silicate glass, aluminum silicate glass, borosilicate soda glass, and shirasu.

  The transparent sealing resin 40 fills the inner space 22 formed by the inner peripheral surface 20a of the reflector 20 and seals the blue LED 30. The transparent sealing resin 40 is made of a transparent sealing resin having translucency. The transparent sealing resin includes a translucent resin as well as a completely transparent resin. The transparent sealing resin preferably has an elastic modulus of 1 MPa or less at room temperature (25 ° C.). In particular, it is preferable to employ a silicone resin or an acrylic resin from the viewpoint of transparency. The transparent sealing resin may further contain an inorganic filler that diffuses light and a phosphor 42 that emits white light using blue light emitted from the blue LED 30 as an excitation source.

  In the light emitting device 1 according to the present embodiment, the silver plating layer 16 is covered with the silver sulfide prevention film 50, and the transparent sealing resin 40 and the reflector 20 are joined.

  The silver sulfidation preventing film 50 suppresses sulfidation of the silver plating layer 16 by covering the silver plating layer 16, and is formed of the silver sulfidation preventing material of the present embodiment described above. When the silver sulfide prevention material contains a layered compound such as montmorillonite or stevensite as clay, a film having a long gas path route and excellent gas barrier properties is formed as shown in FIG.

  The film thickness of the silver sulfide preventing film 50 is preferably 0.005 μm or more and 500 μm or less, more preferably 0.01 μm or more and 500 μm or less, and preferably 0.05 μm or more and 100 μm or less, 0.05 μm More preferably, it is 10 μm or less, 0.05 μm or more and 1 μm or less. By setting the film thickness of the silver sulfide prevention film 50 to 0.005 μm or more and 500 μm or less, it is possible to achieve both the gas barrier property with respect to the silver plating layer 14 and the transparency of the silver sulfide prevention film 50. In this case, this effect is further improved by setting the film thickness of the silver sulfide prevention film 50 to 0.01 μm to 500 μm, 0.01 μm to 100 μm, 0.01 μm to 10 μm, and 0.01 μm to 1 μm. be able to.

  Next, a method for manufacturing the light emitting device 1 according to the first embodiment will be described.

  FIG. 3 is a flowchart illustrating the method for manufacturing the light emitting device according to the first embodiment. As shown in FIG. 3, in the method for manufacturing a light emitting device, first, as a substrate preparation step (step S <b> 101), an insulating base 12 having a copper plated plate 14 wired on the surface is prepared, and a silver plating layer formation step ( As step S102), the silver plating layer 16 is formed on the surface of the copper plating plate.

  Next, the reflector 20 is formed on the surface of the substrate 10 as a reflector forming step (step S103), and the blue LED 30 is mounted on the substrate 10 as a chip mounting step (step S104). The blue LED 30 is mounted on the substrate 10 by die-bonding the blue LED 30 to the silver plating layer 16 on either the anode side or the cathode side in the inner space 22 surrounded by the reflector 20. Thus, the blue LED 30 is electrically connected to the silver plating layer 16 on either the anode side or the cathode side through the die bonding material 32, and the blue LED 30 is surrounded by the reflector 20 and accommodated in the inner space 22. Become.

  Next, as a silver sulfide prevention material application step (step S105), the silver sulfide prevention material of this embodiment is applied to the silver plating layer 16 to cover the silver plating layer 16 with the silver sulfide prevention material.

  The application of the silver sulfide prevention material in the silver sulfide prevention material application step (step S105) is performed by, for example, dropping or spraying the silver sulfide prevention material into the inner space 22 from the surface side of the substrate 10. At this time, the dripping amount or the spraying amount of the silver sulfide prevention material is adjusted so that at least the entire silver plating layer 16 is covered with the silver sulfide prevention material L. In this case, for example, as shown in FIG. 4A, the silver sulfide prevention material L is dropped or dispersed in the inner space 22 so that the silver plating layer 16 and the blue LED 30 are all covered with the silver sulfide prevention material L. As shown in FIG. 4B, the silver plating layer 16 and the blue LED 30 and a part of the inner peripheral surface 20a of the reflector 20 are covered with the silver sulfide preventive material L so that the silver plating layer 16 and the blue LED 30 are covered. The sulfurization preventive material L may be dropped or dispersed in the inner space 22.

  Next, as a drying process (step S106), the silver sulfide prevention film 50 is formed by drying the coating film of the silver sulfide prevention material applied to the silver plating layer 16.

  The drying step can be performed at a temperature at which the solvent volatilizes. For example, when water is used as a solvent, the temperature is preferably 30 ° C. or higher and 80 ° C. or lower, and the temperature range is 30 ° C. or higher and 70 ° C. or lower. It is more preferable to set the temperature range to 30 ° C. or higher and 60 ° C. or lower. The time for maintaining this temperature range can be, for example, 1 minute or more, and is preferably 5 minutes or more and 1 day or less from the viewpoint of obtaining excellent film formability. More preferably, the time is from 30 minutes to 30 minutes.

  When the solvent contains water and alcohol, the drying step is preferably, for example, a temperature range of 30 ° C. or more and 80 ° C. or less, more preferably 35 ° C. or more and 80 ° C. or less, and 40 ° C. or more. Even more preferably, the temperature range is 80 ° C. or lower. The time for maintaining this temperature range can be, for example, 1 minute or longer, and is preferably 5 minutes or longer and 30 minutes or shorter from the viewpoint of obtaining excellent film formability. More preferably, the time is from 15 minutes to 15 minutes.

  By performing the drying process in this manner, the clay diluent L shown in FIG. 4A becomes a silver covering all of the silver plating layer 16 and the blue LED 30 as shown in FIG. 5A. The clay dilution liquid L shown in FIG. 4B becomes the sulfidation preventing film 50, and as shown in FIG. 5B, all of the silver plating layer 16 and the blue LED 30 and the inner peripheral surface 20a of the reflector 20 are formed. Thus, the silver sulfide prevention film 50 covering a part is formed.

  In the present embodiment, it is preferable to sufficiently dry the silver sulfide prevention film 50 under the conditions of 150 ° C. and 30 minutes after the drying step. Thereby, the further improvement effect of the silver sulfide prevention property by narrowing the interlayer of clay can be acquired.

  As shown in FIG. 3, when the drying process (step S106) is completed, the blue LED 30 and the silver plating layer 16 on either the anode side or the cathode side are then wire-bonded as a wire bonding process (step S107). To do. At this time, both ends of the wire are bonded to the blue LED 30 and the silver plating layer 16 so as to break through the silver sulfide prevention film 50 covered with the blue LED 30 and the silver plating layer 16. Is made conductive. The breakage of the silver sulfidation preventive film 50 may be caused by, for example, adjusting the layer thickness of the silver sulfidation preventive film 50, adjusting the load of the bonding head for wire bonding, or vibrating the bonding head. It can be carried out.

  Next, as the transparent sealing resin filling step (step S108), the inner space 22 formed by the inner peripheral surface 20a of the reflector 20 is filled with the transparent sealing resin 40 containing the phosphor 42. Thereby, blue LED30 and the silver plating layer 16 are sealed with the transparent sealing resin 40 (transparent sealing part).

  By performing the transparent sealing resin filling process in this way, the light emitting device 1 shown in FIG. 5A has all of the silver plating layer 16 and the blue LED 30 as shown in FIG. The light-emitting device 1 in which the silver plating layer 16 and the blue LED 30 are sealed with the transparent sealing resin 40 in a state of being covered with the silver sulfide prevention film 50 is shown in FIG. 6 (b), the silver plating layer 16 and the blue LED 30 in a state where all of the silver plating layer 16 and the blue LED 30 and a part of the inner peripheral surface 20a of the reflector 20 are covered with the silver sulfide prevention film 50. The LED 30 is the light emitting device 1 sealed with the transparent sealing resin 40.

  Thus, according to the manufacturing method of the light-emitting device 1 which concerns on 1st Embodiment, after covering the silver plating layer 16 with the silver sulfide prevention material of this embodiment, the coating film of a silver sulfide prevention material is dried. Thus, the silver sulfide prevention film 50 in which clay contained in the silver sulfide prevention material is laminated is formed, and the silver plating layer 16 is covered with the silver sulfide prevention film 50. Thereby, the silver sulfide prevention film 50 which can coat | cover the silver plating layer 16 appropriately can be formed.

  By dropping or dispersing the silver sulfide prevention material of the present embodiment into the inner space 22 of the reflector 20 provided in the light emitting device 1, a silver sulfide prevention film that covers the silver plating layer can be easily formed.

[Second Embodiment]
Next, a second embodiment will be described. The manufacturing method of the light emitting device according to the second embodiment is basically the same as the manufacturing method of the light emitting device according to the first embodiment, but the manufacturing of the light emitting device according to the first embodiment only in the order of the steps. It is different from the method. For this reason, in the following description, only a part different from the method for manufacturing the light emitting device according to the first embodiment will be described, and description of the same part as the method for manufacturing the light emitting device according to the first embodiment will be omitted. .

  FIG. 8 is a flowchart showing a method for manufacturing the light emitting device according to the second embodiment. FIG. 9 is a cross-sectional view of a light emitting device manufactured by the manufacturing method of FIG.

  As shown in FIG. 8, in the method for manufacturing the light emitting device 1 according to the second embodiment, first, similarly to the first embodiment, a substrate preparation step (step S201) and a silver plating layer formation step (step S202). And a reflector formation process (step S203) is performed in this order. The substrate preparation step (step S201), the silver plating layer formation step (step S202), and the reflector formation step (step S203) are the substrate preparation step (step S101) and the silver plating layer formation step (steps) of the first embodiment. S102) and the reflector forming step (step S103).

  Next, as a silver sulfide prevention material application process (step S204), the silver sulfide prevention material of this embodiment is applied to the silver plating layer 16 to cover the silver plating layer 16 with the silver sulfide prevention material.

  Next, as a drying process (step S205), the silver sulfide prevention film 50 is formed by drying the coating film of the silver sulfide prevention material applied to the silver plating layer 16. The drying process (step S205) can be performed in the same manner as the drying process (step S106) of the first embodiment.

  Next, as a chip mounting step (step S206), the blue LED 30 is die-bonded to one of the silver plating layer 16 on the anode side and the cathode side. At this time, similarly to the wire bonding step (step S107) of the first embodiment, the blue LED 30 is bonded to the silver plating layer 16 so as to break through the silver sulfide prevention film 50 covered with the silver plating layer 16. The blue LED 30 and the silver plating layer 16 are electrically connected.

  Next, as a wire bonding step (step S207), the blue LED 30 and the silver plating layer 16 on either the anode side or the cathode side are wire bonded. At this time, since the silver plating layer 16 is covered with the silver sulfide prevention film 50, the silver sulfide prevention film covered with the silver plating layer 16 is the same as in the wire bonding step (step S107) of the first embodiment. One end of the wire is bonded to the silver plating layer 16 so as to break through 50. On the other hand, since the blue LED 30 is not covered with the silver sulfide prevention film 50, the other end of the bonding wire 34 can be bonded to the blue LED 30 as usual. Thereby, blue LED30 and the silver plating layer 16 are conduct | electrically_connected.

  Next, a transparent sealing resin filling step is performed as step S208.

  As described above, according to the method for manufacturing the light emitting device according to the second embodiment, the chip mounting process is performed after the silver sulfide prevention material coating process and the drying process, and as shown in FIG. The light emitting device 1 that is not covered with the silver sulfide prevention film 50 can be manufactured. Thereby, when bonding one end of the bonding wire 34 to the blue LED 30 in the wire bonding step, it is not necessary to break through the silver sulfide prevention film 50 as in the method for manufacturing the light emitting device according to the first embodiment.

[Third Embodiment]
Next, a third embodiment will be described. The manufacturing method of the light emitting device according to the third embodiment is basically the same as the manufacturing method of the light emitting device according to the first embodiment, but only the order of the steps is the manufacturing of the light emitting device according to the first embodiment. It is different from the method. For this reason, in the following description, only a part different from the method for manufacturing the light emitting device according to the first embodiment will be described, and description of the same part as the method for manufacturing the light emitting device according to the first embodiment will be omitted. .

  FIG. 10 is a flowchart showing a method for manufacturing the light emitting device according to the third embodiment. FIG. 11 is a cross-sectional view of a light emitting device manufactured by the manufacturing method of FIG.

  As shown in FIG. 10, in the manufacturing method of the light emitting device 1 according to the third embodiment, first, similarly to the first embodiment, a substrate preparation step (step S301) and a silver plating layer formation step (step S302). In this order. The substrate preparation step (step S301) and the silver plating layer formation step (step S302) are the same as the substrate preparation step (step S101) and the silver plating layer formation step (step S102) of the first embodiment.

  Next, as a silver sulfide prevention material application step (step S303), the silver sulfide prevention material of this embodiment is applied to the silver plating layer 16, and the silver plating layer 16 is covered with the silver sulfide prevention material. At this time, from the viewpoint of workability, it is preferable to apply the silver sulfide prevention material to the entire surface of the substrate 10 on which the silver plating layer 16 is formed, but the silver sulfide prevention material is covered so as to cover only the silver plating layer 16. It may be applied.

  Next, as a drying process (step S304), the silver sulfide prevention film 50 is formed by drying the coating film of the silver sulfide prevention material applied to the silver plating layer 16. The drying process (step S304) can be performed in the same manner as the drying process (step S106) of the first embodiment.

  Next, as a reflector forming step (step S305), the reflector 20 is formed on the surface of the substrate 10. At this time, when the silver sulfide prevention material is applied to the entire surface of the substrate 10 in the silver sulfide prevention material application step (step S303), the reflector 20 is applied to the surface of the silver sulfide prevention film 50 covering the surface of the substrate 10. Form.

  Next, as a chip mounting step (step S306), the blue LED 30 is die-bonded to one of the silver plating layer 16 on the anode side and the cathode side. At this time, similarly to the wire bonding step (step S107) of the first embodiment, the blue LED 30 is bonded to the silver plating layer 16 so as to break through the silver sulfide prevention film 50 covered with the silver plating layer 16. The blue LED 30 and the silver plating layer 16 are electrically connected.

  Next, as a wire bonding step (step S307), the blue LED 30 and the silver plating layer 16 on either the anode side or the cathode side are wire bonded. At this time, since the silver plating layer 16 is covered with the silver sulfide prevention film 50, the silver sulfide prevention film covered with the silver plating layer 16 is the same as in the wire bonding step (step S107) of the first embodiment. One end of the wire is bonded to the silver plating layer 16 so as to break through 50. On the other hand, since the blue LED 30 is not covered with the silver sulfide prevention film 50, the other end of the bonding wire 34 can be bonded to the blue LED 30 as usual. Thereby, blue LED30 and the silver plating layer 16 are conduct | electrically_connected.

  Next, a transparent sealing resin filling process is performed as step S308.

  Thus, according to the manufacturing method of the light emitting device according to the third embodiment, the reflector forming step and the chip mounting step are performed after the silver sulfide prevention material coating step and the drying step, as shown in FIG. Furthermore, the light emitting device 1 in which the blue LED 30 is not covered with the silver sulfide prevention film 50 can be manufactured. Thereby, when bonding one end of the bonding wire 34 to the blue LED 30 in the wire bonding step, it is not necessary to break through the silver sulfide prevention film 50 as in the method for manufacturing the light emitting device according to the first embodiment.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

  Moreover, although the said embodiment demonstrated as what employ | adopts blue LED30 which generate | occur | produces blue light as a light emitting diode bonded to the light-emitting device 1, you may employ | adopt the light emitting diode which generate | occur | produces light other than blue. .

  Moreover, although the light-emitting device 1 of the said embodiment was demonstrated as a thing provided with the reflector 20 surrounding the blue LED 30, it is good also as a thing not provided with such a reflector 20. FIG.

According to the silver sulfide preventive material of the present embodiment, since a silver sulfide preventive film excellent in silver sulfide resistance can be formed, Y ₂ O ₂ S: Eu (red) conventionally used as a phosphor, Sufficient antisulfurization properties can be obtained even in a light emitting device using a sulfur-containing compound such as ZnS: Cu (green), ZnS: Ag (blue), or a compound disclosed in JP-A-8-085787. .

  The silver sulfide preventive material of the present embodiment can be applied to, for example, a plasma display, a liquid crystal display, and the like provided with an antireflection film containing silver in addition to the light emitting device described above.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited to a following example.

Example 1
In the container, 58.81 g of ultrapure water, 0.18 g of powder of montmorillonite (Kunimine Industry Co., Ltd., Kunipia F, aspect ratio 100 to 150), and stevensite (Kunimine Industry Co., Ltd., Smecton, aspect ratio 60) ˜80) powder was added, and the container was shaken by hand and stirred. After further adding 39.2 g of isopropanol in this container, mixing was performed at 2000 rpm for 20 minutes using a rotation / revolution mixer, then defoaming was performed at 2200 rpm for 10 minutes, and a mixture of two types of clays having different aspect ratios ( A mass ratio of 9: 1) was obtained as a silver sulfide preventive material.

(Example 2)
In the container, 58.81 g of ultrapure water, 0.10 g of montmorillonite (Kunimine Industry Co., Ltd., Kunipia F, aspect ratio 100-150), and stevensite (Kunimine Industry Co., Ltd., smecton, aspect ratio 60) A mixture of two types of clays having different aspect ratios (mass ratio 5: 5) was obtained as a silver sulfide preventive material in the same manner as in Example 1 except that 0.10 g of the powder (-80) was added.

Example 3
In the container, 58.81 g of ultrapure water, 0.02 g of montmorillonite (Kunimine Industries, Ltd., Kunipia F, aspect ratio 100 to 150), and stevensite (Kunimine Industries, Ltd., smecton, aspect ratio 60) A mixture of two types of clays having different aspect ratios (mass ratio 1: 9) was obtained as a silver sulfide preventive material in the same manner as in Example 1 except that 0.18 g of powder 80-80) was added.

(Comparative Example 1)
In a container, 58.81 g of ultrapure water and 0.20 g of montmorillonite (Kunimine Industries, Ltd., Kunipia F, aspect ratio 100 to 150) powder were placed, and the container was shaken by hand to be stirred. After further adding 39.2 g of isopropanol in this container, mixing at 2000 rpm for 20 minutes using a rotation / revolution mixer, mixing at 2000 rpm for 20 minutes using a rotation / revolution mixer, then defoaming at 2200 rpm for 10 minutes. And an anti-silver sulfide material containing only clay with a large aspect ratio was obtained.

(Comparative Example 2)
A silver sulfide preventive material was obtained in the same manner as in Comparative Example 1 except that 58.81 g of ultrapure water and 0.20 g of smecton (Kunimine Industries, SWN, aspect ratio 50) were put in a container. It was.

[Evaluation of silver sulfide prevention]
3 μl of silver sulfide preventive material was dropped once on “TOP LED OP4” (manufactured by Enomoto Co., Ltd.), which is an LED lead frame provided with a silver plating layer on a copper plate, using a micropipettor. A lead frame in which a silver sulfide prevention material was dropped was placed in a thermostatic bath and dried at 50 ° C. for 10 minutes. After drying, the temperature of the thermostatic bath was raised to 150 ° C. and heated for 30 minutes to obtain a test sample.

  An aluminum cup containing sulfur powder (0.5 g) was placed in a sealable glass bottle, and a stainless steel wire mesh was placed on the cup. Next, the test sample was placed on the wire mesh so that the side on which the silver sulfide prevention material was dropped was faced up so that the samples did not overlap each other. After sealing the glass bottle, it was stored at 100 ° C. for 2 hours and 4 hours, respectively. Take out the test sample from the glass bottle and observe the antisulfation property with an optical microscope. The case where all the colors changed was designated as “x”.

DESCRIPTION OF SYMBOLS 1 ... Light-emitting device, 10 ... Board | substrate, 10a ... Surface of board | substrate, 12 ... Base | substrate, 14 ... Copper plating board, 16 ... Silver plating layer, 20 ... Reflector (light reflection part), 20a ... Inner peripheral surface, 20b ... Top surface 20c ... outer peripheral surface, 22 ... inner space, 30 ... blue LED (blue light emitting diode), 32 ... die bond material, 34 ... bonding wire, 40 ... transparent sealing resin (transparent sealing portion), 42 ... phosphor, 50 ... Silver sulfide prevention film, L ... Silver sulfide prevention material.

Claims (7)

Silver sulfide preventive material containing two or more types of clay with different aspect ratios. And an aspect ratio of 1 to 80 clay, aspect ratio contains a clay 81-1000, silver sulfide prevention material according to claim 1. An application step of applying the silver sulfide prevention material according to claim 1 or 2 to form a coating film of the silver sulfide prevention material on the surface of the metal layer containing silver;
A drying step of drying the coating film;
A method for forming a silver sulfide prevention film. The method for forming a silver sulfide prevention film according to claim 3 , wherein the metal layer is a silver plating layer. The method for forming a silver sulfide prevention film according to claim 3 or 4 , wherein the thickness of the coating film after drying is 0.005 µm or more. A method for manufacturing a light emitting device, comprising: a substrate having a silver plating layer; and a light emitting element mounted on the substrate,
On the surface of the silver plating layer, an application step of applying the silver sulfide prevention material according to claim 1 or 2 to form a coating film of the silver sulfide prevention material;
A drying step of drying the coating film;
A method for manufacturing a light emitting device. The manufacturing method of the light-emitting device of Claim 6 whose thickness of the said coating film after drying is 0.005 micrometer or more.

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