JP2019068053A - Light emitting device - Google Patents

Abstract

To provide a light emitting device in which light extraction efficiency hardly decreases even when driven for a long time.SOLUTION: A wire 1 for connecting a metal member of a light emitting device and a pad electrode includes a laminated structure at least including: a core material 11 having a diameter of 10 to 30 μm mainly composed of Cu; an intermediate layer 12 having a thickness of 30 nm or more and 100 nm or less mainly composed of Pd coated on a surface thereof; and a surface layer 13 having a thickness of 40 nm or more and 300 nm or less mainly composed of Ag coated on the surface of the intermediate layer 12.SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to a light emitting device.

  A coated wire obtained by coating a wire core material mainly composed of Cu with a material having high reflectance as a wire for connecting a pad electrode of a semiconductor light emitting device (hereinafter, also simply referred to as "light emitting device") and an electrode of a package. Have been proposed (Patent Documents 1 and 2).

  However, in Patent Document 1, although Cu is used as the wire core material and Ag is used to enhance the light extraction efficiency, Cu of the core material is easily thermally diffused to Ag of the surface layer. Further, Patent Document 2 proposes a coated Cu wire of a core material made of Cu, an intermediate layer made of Pd, and a surface layer made of Ag.

Japanese Patent Application Publication No. 2007-80990 JP, 2012-039079, A

  With the above-mentioned coated wire, the light extraction efficiency tends to be reduced over a long period of time.

The present disclosure includes the following configurations.
A light emitting device comprising a light emitting element provided with a pad electrode, and a metal member connected to the pad electrode via a wire, wherein the wire is a core material mainly composed of Cu, and an intermediate mainly composed of Pd A light emitting device comprising: a layer; and a surface layer containing Ag as a main component.

  As described above, when the light emitting device is driven for a long period of time, the light emitting device can be less likely to have reduced light extraction efficiency.

It is a schematic perspective view for explaining a light emitting device of an embodiment. It is a schematic sectional drawing for demonstrating the light-emitting device of one Embodiment. It is a schematic sectional drawing for demonstrating the multilayer bonding wire of one Embodiment. FIG. 6 is a 1000 × SEM photograph showing the surface of the bonding wire of Example 1. FIG. FIG. 5 is a 5000 × SEM photograph showing the surface of the bonding wire of Example 1. FIG. It is a cross-sectional observation photograph by FIB-SEM which shows the cross section of the bonding wire of Example 1. FIG. It is a table | surface which shows the structure and measurement result of the light-emitting device of the Example in connection with one Embodiment of this invention, and the light-emitting device of a comparative example.

  The mode for carrying out the present invention will be described below with reference to the drawings. However, the form shown below is an example of a light emitting device for embodying the technical concept of the present invention, and the present invention is not limited to the following. Further, the dimensions, materials, shapes, relative arrangements and the like of the component parts described in the embodiments are not intended to limit the scope of the present invention to only the specific ones unless specifically described, and are merely illustrative. It is only Note that the sizes and positional relationships of members shown in each drawing may be exaggerated for the sake of clarity.

  1A and 1B show a light emitting device 100 according to the first embodiment. In FIG. 1A, the sealing member is omitted. The light emitting device 100 includes a package 10, a light emitting element 3 mounted on the package 10, and a wire 1. The package 10 includes a metal member 2 functioning as a pair of positive and negative electrodes, and a resin molded body 4 integrally holding the metal member 2. The light emitting element 3 includes a semiconductor multilayer structure 32 including a light emitting layer, and a pad electrode 31 formed on the top surface of the multilayer structure 32. The wire 1 connects the metal member 2 and the pad electrode 31. The metal member 2 functions as a mounting member on which the light emitting element 3 is mounted. The metal member 2 also functions as a pair of positive and negative electrodes for energizing the light emitting element 3 via the wire 1.

  As shown in the schematic cross sectional view of FIG. 2, the wire 1 of the present embodiment includes a core 11 mainly composed of Cu, an intermediate layer 12 mainly composed of Pd, and a surface layer 13 mainly composed of Ag. including. The diameter of the core material 11 mainly composed of Cu is, for example, 10 μm to 30 μm. Further, the thickness of the intermediate layer 12 containing Pd as a main component is, for example, 30 nm or more and 100 nm or less. Furthermore, the thickness of the surface layer 13 mainly composed of Ag is, for example, 40 nm or more and 300 nm or less.

(Wire 1)
The wire 1 electrically connects the metal member 2 and the pad electrode 31 metal member metal member of the light emitting element 3. The wire 1 will be described with reference to FIG. The wire 1 of the present embodiment includes a core 11 mainly composed of Cu, an intermediate layer 12 mainly composed of Pd coated on the surface thereof, and Ag further coated on the surface of the intermediate layer 12 And a surface layer 13 to be provided.

  The core material 11 contains Cu as a main component, preferably contains at least 95% or more of Cu, and more preferably contains at least 97% or more of Cu. The core material 11 may be made of Au, Ag, or the like depending on productivity, such as bonding property, ease of forming a ball, appropriate elongation, appropriate loop shape, appropriate hardness, and the shape of the light emitting device 100. Additives or alloy metals such as Zn, Sn, V, B, Ti, Mg, P, S may be added. The diameter of the core material 11 can be appropriately selected according to the shape, output, and the like of the light emitting device 100. The diameter of the core material 11 is preferably, for example, 10 μm or more and 30 μm or less.

  The intermediate layer preferably contains at least one selected from Cu, Te, Ge, Se, Au, and Ag. The intermediate layer 12 preferably contains Pd as a main component, preferably contains 90% or more of Pd, and more preferably 95% or more of Pd. The intermediate layer 12 has heat resistance, corrosion resistance, oxidation resistance, adhesion, ease of ball formation, an appropriate elongation, an appropriate loop shape, productivity such as an appropriate hardness, and the shape of the light emitting device 100. Additives or alloy metals may be added as appropriate depending on the situation. The intermediate layer 12 may contain, for example, a very small amount of Se, Ge, Bi, Te, etc., which is expected to improve the heat resistance. When the Pd intermediate layer is produced by electroplating, a plating solution to which these additives are added may be used.

  The surface layer preferably contains at least one selected from Pd, Au, Se, S, C, N, and O. In particular, the surface layer 13 containing Ag as a main component is preferably high purity Ag that does not contain other than unavoidable impurities. The surface layer 13 may contain a trace additive such as Se or S to improve the heat resistance and the light reflectance. In the case of producing the surface layer 13 containing Ag as a main component by electroplating, it may be possible to appropriately add a Se compound and an S compound as an additive to the used Ag plating solution.

  As a method of manufacturing the wire 1, first, the core material 11 having a diameter larger than the diameter of the target wire is prepared, and after forming the plating layer thicker than the target intermediate layer and surface layer, wire drawing is performed. Apply. The core material, the intermediate layer, the surface layer, and the wire will be described using the same names before and after wire drawing.

  The core material 11 mainly composed of Cu having a diameter of 2 mm-6 mm and wound into a coil shape is first plated by electroplating to a thickness of about several μm of Pd plating to be the intermediate layer 12, and then the surface layer 13 Similarly, Ag plating is performed to a thickness of about several μm. While heat treating the thus manufactured wire of several mm in diameter, wire drawing can be repeated several stages through a wire drawing die having an appropriate hole shape, for example, a wire with a diameter of 10 μm to 30 μm can be manufactured. It is preferable to adjust the plating thickness of Pd or Ag formed in the plating process before wire-drawing according to the degree of wire-drawing later. Since the wire drawing process is performed while heating in this manner, the vicinity of the interface between the core material 11, the intermediate layer 12, and the surface layer 13 is alloyed to some extent because it thermally diffuses each other. As for the degree of alloying, it is preferable to adjust various properties of the wire 1 by adjusting conditions such as temperature and time of heat treatment.

  The intermediate layer 12 containing Pd and the surface layer 13 containing Ag are respectively plated by electroplating using the core material 11 mainly composed of Cu with a diameter of 25 μm as the wire 1 and wire drawing is not performed. It is also possible to produce the desired wire 1.

(Package 10)
The light emitting device 100 of the present embodiment has a package 10 including at least the metal member 2. These packages 10 can include a metal member 2 and an insulating base 4.

  The package 10 has, for example, a rectangular outer peripheral shape in a plan view, and a recess having an opening on the top surface. The concave portion has, for example, a square shape in plan view of the opening in which the metal member 2 is exposed at the bottom surface. On the lower surface of the package 10, a part of the pair of metal members 2 is exposed as an external terminal portion. The plan view shape of the package 10 may be a rectangular outer shape, a horizontal shape, a polygon, or a shape combining them. When the package 10 of the light emitting device 100 has a recess, the inner side surface of the side wall of the recess may be provided at an inclined angle with respect to the bottom as shown in FIG. You may have a level | step difference surface in the side. In addition, the height of the wall and the shape of the opening can be appropriately selected according to the purpose and application. Preferably, the metal member 2 is provided inside the recess, and the side wall portion may be provided with a metal member in addition to the bottom surface portion as in the present embodiment.

(Metal member 2)
The metal member 2 can function as a light reflecting member having high reflection to light from the light emitting element 3. For example, the metal member 2 has an Au- or Ag-containing layer on the surface, and is provided in the light emitting device 100 so as to efficiently reflect light emitted from the light emitting element 3 or a wavelength conversion member described later.

  When the metal member 2 is used as a light reflecting member, it may be used in the light emitting device 100 in any form as long as the light emitted from the light emitting element 3 can be reflected. For example, as shown to FIG. 1A etc., it may be arrange | positioned under the light emitting element 3, and it may be provided in the reflector shape surrounding the light emitting element 3. FIG. Further, the metal member 2 may be a plate-like lead frame as shown in FIG. 1A or the like, or may be a wiring formed on an insulating base. The metal member 2 may also have a function as a mounting member for mounting the light emitting element 3, a heat radiating member for radiating heat, and a metal member electrically connected to the light emitting element 3. For this reason, it is preferable that the metal member 2 is excellent in heat dissipation, electroconductivity, and bondability according to the function.

  The surface of the metal member 2 preferably has a reflectance of 70% or more, particularly preferably 80% or more, to light of a wavelength in the visible light range. Thereby, light extraction efficiency can be improved. In addition, high gloss is preferable, and the glossiness is 0.5 or more, more preferably 1.0 or more, and further preferably 1.6 or more. The glossiness shown here is a number obtained by irradiation at 45 ° and vertical light reception using a micro surface color difference meter VSR 300A manufactured by Nippon Denshoku Kogyo. The metal member preferably has a surface containing at least one or more selected from Ag, Au, Pd, Rh, and Pt. In particular, the surface of the metal member is preferably a layer containing Au or Ag.

  The Au- or Ag-containing layer of the metal member 2 may be provided on all surfaces of the metal member 2 or may be partially provided on the surface of the metal member 2. That is, the Au or Ag-containing layer may be provided on at least a part of the surface of the metal member 2. For example, in the light emitting device 100 shown in FIGS. 1A and 1B, the metal member 2 is exposed at the bottom of the recess, and thus the surface of the metal member 2 is irradiated with light from the light emitting element 3 Preferably, an Ag-containing layer having a high reflectance is provided. In the metal member 2, the embedded portion embedded inside the side wall portion of the base 4, the external terminal portion exposed to the outside of the base 4, and the mounting portion exposed to the lower surface side of the light emitting device 100 It is not necessary to provide an Au or Ag containing layer. When the Au or Ag-containing layer is provided on a part of the metal member 2 as described above, the film or the like is protected with a mask or a protective tape by using a mask to protect the portion where the Au or Ag-containing layer is not formed. Can.

  The Au- or Ag-containing layer of the metal member 2 may have the same thickness over the entire area, or may have different thicknesses. The cost can be reduced by partially reducing the thickness of the Au or Ag containing layer. For example, an Au- or Ag-containing layer can be provided on the upper and lower surfaces of the metal member 2 and the thickness on one side can be greater than the other. It is preferable to provide a thick Au or Ag-containing layer on the upper surface of the metal member 2 on which the light emitting element 3 is mounted or in the vicinity of the light emitting element 3 from the viewpoint of improving light extraction efficiency. Since the high reflectance Au or Ag containing layer is not provided on the lower surface of the metal member, the amount of materials such as Au or Ag can be reduced, and the cost can be reduced.

  In order to form an Au- or Ag-containing layer on the surface of the metal member 2, a plating method is preferable from the viewpoint of mass productivity. In particular, when forming by electrolytic plating, if necessary, brighteners such as Se brighteners, Sb brighteners, S brighteners, Tl additives, Pb additives, As brighteners, organic brighteners, etc. The glossiness can be improved by using an additive and an additive. Thereby, the metal member 2 excellent in corrosion resistance can be obtained while having high glossiness.

  Moreover, in order to raise the light reflectivity of the metal member 2, it is preferable that the flatness of a base material is as high as possible. For example, the surface roughness Ra is preferably 0.5 μm or less. Thereby, the flatness of the Au or Ag-containing layer provided on the base material can be enhanced, and the light reflectance of the metal member 2 can be favorably enhanced. The flatness of the base material can be increased by performing treatments such as rolling treatment, physical polishing, chemical polishing, and the like.

(Substrate)
The package 10 of the light emitting device 100 includes a base 4. The base 4 is a member using a resin that holds the pair of metal members 2 integrally as a base.

As the substrate 4, a thermosetting resin or a thermoplastic resin can be used, and in particular, a thermosetting resin is preferably used. As the thermosetting resin, a resin having low gas permeability as compared to the resin used for the sealing member 6 described later is preferable, and specifically, an epoxy resin composition, a silicone resin composition, a silicone-modified epoxy resin, etc. A modified epoxy resin composition, a modified silicone resin composition such as an epoxy modified silicone resin, a polyimide resin composition, a modified polyimide resin composition, a urethane resin, a modified urethane resin composition, and the like can be mentioned. In the base material of such a substrate 4, fine particles such as TiO ₂ , SiO ₂ , Al ₂ O ₃ , MgO, MgCO ₃ , CaCO ₃ , Mg (OH) ₂ , Ca (OH) ₂ and the like as a filler (filler) It is preferable to adjust the light transmittance by mixing them so as to reflect about 60% or more of the light from the light emitting element, and more preferably to reflect about 90%.

  The base 4 is not limited to one using the above-described resin as a base material, and may be formed of ceramic, an inorganic material such as glass, metal or the like. Thus, the light emitting device 100 can be highly reliable with less deterioration and the like.

(Light-emitting element 3)
For example, as shown in FIG. 1A, the light emitting element 3 can be placed on the metal member 2 exposed to the bottom surface of the recess of the package 10. The light emitting element 3 is preferably mounted on the metal member 2 having high reflectance and / or gloss. Thereby, the light extraction efficiency of the light emitting device 100 can be improved.

  The light emitting element 3 can select a semiconductor light emitting element of any wavelength. The light emitting element 3 includes a laminated structure 32 including a semiconductor layer including a light emitting layer and the like, and a pad electrode 31. As the stacked structure body 32, for example, as the light emitting element 3 emitting blue or green light, one using a nitride-based semiconductor such as InGaN, GaN, or AlGaN or GaP can be used. In addition, as the stacked light emitting element, GaAlAs, AlInGaP, or the like can be used for the stacked structure 32. Furthermore, the light emitting element 3 which consists of materials other than this can also be used. The composition, emission color, size, number and the like of the light-emitting elements 3 to be used can be appropriately selected according to the purpose.

  When the light emitting device 100 includes a wavelength conversion member, a nitride semiconductor capable of emitting a short wavelength capable of efficiently exciting the wavelength conversion member can be suitably exemplified as the stacked structure 32 of the light emitting element 3. The laminated structure 32 of the light emitting element 3 can select various emission wavelengths depending on the material of the semiconductor layer and the mixed crystal ratio thereof. Further, the light emitting element 3 can output not only light in the visible light region but also ultraviolet light and infrared light.

  The light emitting element 3 has positive and negative pad electrodes 31 electrically connected to the metal member 2. These positive and negative electrodes may be provided on one side, or may be provided on both the upper and lower sides of the light emitting element 3. The pad electrode preferably has a surface made of at least one selected from Al, Pd, Pt, Rh, and Ru. The connection between the metal member 2 functioning as a conductive member and the light emitting element 3 may be only the wire 1 or, in addition to the wire 1, a conductive bonding member 5 is used as a bonding member 5 described later. It may be connected.

  When the plurality of light emitting elements 3 are provided, the pad electrodes 31 of the light emitting elements 3 may be connected by the wire 1. Further, in the case where a plurality of light emitting elements 3 are provided, as shown in FIGS. 1A and 1B, a lead may be connected to each of the light emitting elements 3.

(Joining member 5)
The bonding member 5 is a member for fixing and mounting the light emitting element 3 on the package 10. As a preferable material, a conductive paste such as silver, gold or palladium, a eutectic solder material such as Au-Sn or Sn-Ag-Cu, or a brazing material such as a low melting point metal as the conductive bonding member 5 Bonding between the same materials using particles of Cu, Ag, Au or films, or the like can be used. As the insulating bonding member 5, an epoxy resin composition, a silicone resin composition, a polyimide resin composition, its modified resin, a hybrid resin, or the like can be used. When using these resins, in consideration of deterioration due to light and heat from the light emitting element 3, a metal layer with high reflectance such as Al film or Ag film or a dielectric reflective film is provided on the mounting surface of the light emitting element 3. be able to.

(Sealing member 6)
The light emitting device 100 may include the sealing member 6. By providing the sealing member 6 so as to cover members such as the light emitting element 3, the metal member 2, the wire 1 and a protective film described later, the coated member can be protected from dust, moisture, and external force. The reliability of the light emitting device 100 can be improved. In particular, by providing the sealing member 6 on the protective film after forming the protective film, the protective film can be protected, and thus the reliability is preferably enhanced.

  The sealing member 6 preferably has a light transmitting property capable of transmitting the light from the light emitting element 3 and has light resistance which is not easily deteriorated by light. Specific examples include insulating resin compositions having translucency capable of transmitting light from a light emitting element, such as silicone resin compositions, modified silicone resin compositions, modified epoxy resin compositions, and fluorocarbon resin compositions. be able to. In particular, a hybrid resin containing at least one or more resins having a siloxane skeleton as a base such as dimethyl silicone, phenyl silicone having a small phenyl content, and fluorine-based silicone resin can also be used.

  As a method of forming the sealing member 6, when the sealing member 6 is a resin, a potting (dropping) method, a compression molding method, a printing method, a transfer molding method, a jet dispensing method, spray coating, or the like can be used. In the case of the package 10 having a recess as shown in FIGS. 1A and 1B, the potting method is preferable, and in the case of using a flat package, the compression molding method or the transfer molding method is preferable.

  The sealing member 6 can be provided to fill the inside of the recess of the base 4 as shown in FIG. 1B.

  The shape of the outer surface of the sealing member 6 can be variously selected according to the light distribution characteristic and the like required for the light emitting device 100. For example, by making the upper surface into a convex lens shape, a concave lens shape, a Fresnel lens shape, a rough surface, or the like, it is possible to adjust the directivity characteristics and the light extraction efficiency of the light emitting device.

  The sealing member 6 can also contain a colorant, a light diffusing agent, a metal member, various fillers, a wavelength conversion member, and the like.

  The wavelength conversion member is a material that converts the wavelength of the light of the light emitting element 3. When the light emitted from the light emitting element 3 is blue light, a yttrium aluminum garnet phosphor (hereinafter referred to as "YAG: Ce"), which is a kind of aluminum oxide phosphor, is preferably used as the wavelength conversion member. Used for Since the YAG: Ce phosphor partially absorbs blue light from the light emitting element to emit complementary yellow light, the high-power light emitting device 100 emitting white mixed color light is relatively simple. Can be formed.

(Protective film)
The light emitting device 100 may further include a protective film. The protective film is an insulating member that covers the metal member 2, the wire 1, and the like. Specifically, the protective film is a member that at least covers the Ag-containing layer provided on the surface of the wire 1 or the metal member 2 and that mainly suppresses discoloration or corrosion of the Ag-containing layer on the surface of the wire 1 and the metal member 2 is there. Furthermore, optionally, the surface of a member other than the metal member 2 such as the wire 1, the light emitting element 3, the bonding member 5, the base (resin molding) 4 or the like is covered May be The protective film is a translucent member. Therefore, the high reflectance of the surface layer 13 of the wire 1 can be maintained. The material of the protective film is, for example, Al ₂ O ₃ , SiO ₂ , TiO ₂ , ZrO ₂ , ZnO, Nb ₂ O ₅ , MgO, In ₂ O ₃ , Ta ₂ O ₅ , HfO ₂ , SeO, Y ₂ O _And oxides such as SnO ₂ , nitrides such as AlN, TiN, and ZrN, and fluorides such as ZnF ₂ and SrF ₂ . These may be used alone or in combination. Alternatively, they may be stacked.

  Since the surface layer 13 of the wire 1 contains Ag as a main component, by covering the surface of the wire 1 with a protective film, sulfurization and oxidation of the surface layer 13 can be suppressed. Furthermore, when the surface of the metal member 2 contains Ag, covering the surface with a protective film can prevent the Ag from being discolored due to sulfurization or oxidation.

  The protective film is continuously provided on the surface of the wire 1, the light emitting element 3, the bonding member 5, the base 4 and the like from the surface of the metal member 2 including the Au or Ag containing layer.

  The protective film can be formed by a sputtering method or a chemical vapor deposition method, but is particularly preferably formed by an atomic layer deposition method (ALD (Atomic Layer Deposision) method). According to the ALD method, it is possible to form a very uniform protective film, and the formed protective film is denser compared to protective films obtained by other film forming methods. Sulfurization of the Ag-containing layer on the surface of the member 2 can be very effectively prevented.

  The light emitting device 100 can include various members in addition to the above. For example, a Zener diode can be mounted as a protective element.

  As Example 1-4, the wire 1 shown in FIG. 5 was prepared, and the light-emitting device 100 shown to FIG. 1A and 1B was manufactured.

  In Examples 1 to 4, in order to avoid the heat treatment effect at the time of wire drawing, a commercially available Cu wire with a diameter of 25 μm was prepared as the core material 11. The Cu wire was degreased and then acid neutralized with a 10% aqueous sulfuric acid solution.

Next, plating of the intermediate layer 12 was performed using the following bath composition.
(Pd plating solution)
Tetraamminepalladium chloride, as Pd metal = 5 g / L
Ammonium nitrate = 150 g / L
3 Pyridine sulfonic acid sodium = 3 g / L
pH 8.5 Adjustment with ammonia water Pd plating was performed at a liquid temperature of 50 ° C. and a current density of 1 A / dm ² .

After Pd plating, it was washed with water and then plating of surface layer 13 was performed using the following bath composition.
(Ag plating solution)
Silver cyanide potassium = 70 g / L
Potassium cyanide = 120 g / L
Potassium carbonate = 30 g / L
Ag plating was performed at a liquid temperature of 30 ° C. and a current density of 2 A / dm ² to form a wire 1.

  The plating thickness of the intermediate layer (Pd plating) 12 and the surface layer (Ag plating) 13 was adjusted by the plating time. As for each plating thickness, three pieces of SEM images of the cross section of the prepared wire 1 were taken with an FIB-SEM apparatus, and the cross section was photographed at three points in an arbitrary place. The average value of the maximum and minimum film thicknesses in the three photographs was taken as the film thickness of the intermediate layer (Pd plating) 12 and the film thickness of the surface layer (Ag plating) 13.

  The surface SEM photograph of the wire of Example 1 was shown in FIG. Moreover, the cross-sectional observation photograph by FIB-SEM was shown in FIG.

  Next, a Ni plating layer of 2 μm in thickness, a Pd plating layer of 0.03 μm in thickness, and an Au plating layer of 0.004 μm in thickness are further formed on the surface of the base material of Mitsubishi 194 copper alloy 194 194 alloy. The metal member 2 which is a pair of lead frame which formed Ag layer of 2.5 micrometers in thickness in order by electrolytic plating was prepared.

  Furthermore, such leads as shown in FIGS. 1A and 1B respectively formed a package 10 embedded in the substrate 4 by transfer molding. Incidentally, until the light emitting device 100 is singulated, each step is performed in the state of an assembly of packages 10 in which a plurality of bases 4 are formed on a lead frame in which a plurality of pairs of leads are connected. For convenience, one light emitting device 100 (single) shown in FIGS. 1A and 1B will be described.

  The package 10 of the present embodiment has a recess, and the metal member 2 is exposed at the bottom of the recess. On the metal member 2, a light transmitting resin was used as the bonding member 5, and the light emitting element 3 provided with positive and negative electrodes on the upper surface was placed and bonded. Thereafter, the metal member 2 and the pad electrode of the light emitting element 3 were connected by the wire 1 manufactured as described above. In addition, the package 10 was mounted on the support stand, and the support stand performed the following wire connection processes in the state heated by heater temperature 180 degreeC.

An example of the connection condition of the wire 1 is given below.
The connection conditions (first bond conditions) for connecting the wire 1 onto the pad electrode 31 are 70 g for the weight, 150 kHz for the oscillation frequency of the ultrasonic wave, and 30 msec for the ultrasonic wave application time.

  Connection conditions for extending the wire 1 connected on the pad electrode 31 and connecting it to the connection portion on the metal member 2 (the second bond condition is that the weight is 65 g, the oscillation frequency of the ultrasonic wave is 60 kHz, and the ultrasonic wave is applied) The time is 10 msec.

Thereafter, SiO ₂ was formed to a thickness of 60 nm as a protective film by using the ALD method, and then, a sealing member fat 6 of a translucent resin containing a YAG fluorescent substance was formed in the recess.

The result of measuring the total luminous flux of the light emitting device manufactured in this way is shown in FIG.
Further, FIG. 5 also shows the maintenance rates of total luminous flux after the initial reliability of luminous flux and the test of light emission reliability with a current of 65 mA (sulfidation test). The conditions of the sulfurization test are conducted by disposing the light emitting device in an atmosphere of mixed gas of H ₂ S and NO ₂ . Specifically, the light-emitting device 100 is stored for 600 hours in an atmosphere at a temperature of 40 ° C. and a relative humidity of 75% at a concentration of H ₂ S: 2 ppm and NO ₂ : 4 ppm. The luminous flux maintenance factor is the power ratio to the power before this sulfurization test.

  As shown in FIG. 5 in the same manner as in Example 1 above, as in Examples 2 to 4, wires 1 of various plating specifications were prepared, and a light emitting device 100 was similarly prepared.

  Further, as Comparative Example 1, a light emitting device was manufactured in the same manner as Example 1 except that an Au wire having a diameter of 18 μm was used.

In addition, as Comparative row 2, a light emitting device was manufactured in the same manner as Example 1, except that only Pd 40 nm was plated on the core material Cu. Furthermore, as Comparative Example 3, as shown in FIG. 5, wires 1 of various plating specifications were prepared, and a light emitting device 100 was similarly prepared.

  The result of measuring the total luminous flux of the light emitting device manufactured in this way is shown in FIG.

  As shown in FIG. 5, all of the light emitting devices of Examples 1 to 4 showed high initial total luminous flux regardless of the thickness of the surface layer (Ag plating) 13 and also high luminous flux maintenance factor in the reliability test. Can maintain However, in the light emitting device of the comparative example, when the Au wire and the Ag surface layer 13 were not present as in the comparative example 1 or 2, only a low initial total luminous flux was obtained. On the other hand, although there was no Pd intermediate layer as in Comparative Example 3, a high initial total luminous flux could be obtained, the results of the long-term reliability test showed a reduction in the total luminous flux.

    The reflectance of the Ag-containing layer can be improved and the light extraction efficiency of the light emitting device can be expected to be improved by any of the examples, and it is also found that the total luminous flux maintenance rate by the light emission reliability test is stable. .

100 ... light emitting device 1 ... wire 2 ... metal member 3 ... light emitting element (31 ... pad electrode, 32 ... laminated structure)
4 ... Substrate (Resin molded body)
DESCRIPTION OF SYMBOLS 5 ... Bonding member 6 ... Sealing member 10 ... Package 11 ... Core material 12 which has Cu as a main component Intermediate layer 13 which has Pd as a main component ... Surface layer which has Ag as a main component

Claims (6)

What is claimed is: 1. A light emitting device comprising: a light emitting element having a pad electrode; and a metal member connected to the pad electrode via a wire,
The light emitting device, wherein the wire includes a core material mainly composed of Cu, an intermediate layer mainly composed of Pd, and a surface layer mainly composed of Ag.   The light emitting device according to claim 1, wherein the thickness of the intermediate layer is 30 nm or more and 100 nm or less, and the thickness of the surface layer is 40 nm or more and 300 nm or less.   The light emitting device according to claim 1, wherein the intermediate layer contains at least one selected from Cu, Te, Ge, Se, Au, and Ag.   The light emitting device according to any one of claims 1 to 3, wherein the surface layer contains at least one selected from Pd, Au, Se, S, C, N, and O. The light emitting device according to any one of claims 1 to 4, wherein the pad electrode has a surface of at least one selected from Al, Pd, Pt, Rh, and Ru. The light emitting device according to any one of claims 1 to 5, wherein the metal member includes at least one or more surface selected from Ag, Au, Pd, Rh, and Pt.

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