JP6414334B1 - Light emitting device - Google Patents

Abstract

A light emitting device having a CSP structure, which is embedded in a support substrate 10, a first metal film 40 disposed on the support substrate 10, and a part of an upper portion of the first metal film 40, and has a first side surface and a bottom surface. The second metal film 30 covered with the metal film 40 and the light emitting element 20 disposed on the first metal film 40 so as to cover the upper surface of the second metal film 30 are provided. The reflectance of the light emitted from the light emitting element 20 is higher than that of the first metal film 40, and the first metal film 40 is less likely to cause migration than the second metal film 30.

Description

  The present invention relates to a light emitting device to which a chip size package technology is applied.

  A chip size package (CSP) is applied to a light emitting device in order to improve the light emitting efficiency and reduce the size of the light emitting device using a light emitting element such as a light emitting diode (LED) as a light source (for example, Patent Document 1). reference.). Furthermore, in order to realize a semiconductor light emitting device of extremely small size, the development of a structure in which the semiconductor substrate used for forming the semiconductor layer constituting the light emitting element is separated from the semiconductor layer and the semiconductor layer is enclosed in a package such as a resin is proceeding. It has been. In this structure, not a semiconductor substrate but a resin substrate or the like can be used as a support substrate that supports the light emitting element, so that an inexpensive light emitting device can be provided.

  In a light emitting device having a structure to which CSP is applied (hereinafter referred to as “CSP structure”), an electrode connected to the light emitting element is disposed on a surface opposite to the light extraction surface. For this reason, there is no thing which shields the emitted light of a light emitting element in the direction of a light extraction surface, and the light emission efficiency of a light-emitting device improves. In addition, by disposing the second metal film on the surface opposite to the light extraction surface, the light emitted from the light emitting element traveling in the direction opposite to the light extraction surface can be reflected toward the light extraction surface. For this reason, the brightness | luminance of output light improves.

JP 2014-150196 A

  However, an Ag film, an Al film, or the like used for the second metal film is likely to cause migration. For this reason, there existed a problem that the reliability of a light-emitting device fell.

  In view of the above problems, an object of the present invention is to provide an inexpensive light emitting device in which a decrease in reliability is suppressed.

According to one aspect of the present invention, a supporting lifting the substrate, a first metal layer disposed on the supporting substrate is embedded in a part of the upper portion of the first metal film, the side surface and the bottom surface to the first metal film A covered second metal film; and a light emitting element disposed on the first metal film so as to cover an upper surface of the second metal film. The support substrate is a ceramic substrate, and the ceramic substrate is a first substrate. It has a structure in which a ceramic layer and a second ceramic layer having a larger linear expansion coefficient than the first ceramic layer are laminated, the first ceramic layer is disposed on the side close to the light emitting element, and the second metal film is There is provided a light emitting device having a CSP structure in which the reflectance of the light emitted from the light emitting element is higher than that of the first metal film, and the first metal film is less likely to cause migration than the second metal film.

  ADVANTAGE OF THE INVENTION According to this invention, the cheap light-emitting device by which the fall of reliability was suppressed can be provided.

It is typical sectional drawing which shows the structure of the light-emitting device which concerns on embodiment of this invention. It is process sectional drawing for demonstrating the manufacturing method of the light-emitting device which concerns on embodiment of this invention (the 1). It is process sectional drawing for demonstrating the manufacturing method of the light-emitting device which concerns on embodiment of this invention (the 2). It is process sectional drawing for demonstrating the manufacturing method of the light-emitting device which concerns on embodiment of this invention (the 3). It is process sectional drawing for demonstrating the manufacturing method of the light-emitting device which concerns on embodiment of this invention (the 4). It is process sectional drawing for demonstrating the manufacturing method of the light-emitting device which concerns on embodiment of this invention (the 5). It is typical sectional drawing which shows the structure of the light-emitting device which concerns on the 1st modification of embodiment of this invention. It is typical sectional drawing which shows the structure of the light-emitting device which concerns on the 2nd modification of embodiment of this invention. It is typical sectional drawing which shows the structure of the light-emitting device which concerns on the 3rd modification of embodiment of this invention. It is typical sectional drawing which shows the structure of the light-emitting device which concerns on other embodiment of this invention.

  Next, an embodiment of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. Further, the embodiments described below exemplify apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention includes the shape, structure, arrangement, etc. of components. It is not specified to the following. The embodiment of the present invention can be variously modified within the scope of the claims.

  As shown in FIG. 1, the light emitting device according to the embodiment of the present invention includes a support substrate 10, a first metal film 40 disposed on the support substrate 10, and a part of an upper portion of the first metal film 40. The embedded second metal film 30 and the light emitting element 20 disposed on the first metal film 40 so as to cover the upper surface of the second metal film 30 are provided. The side and bottom surfaces of the second metal film 30 are covered with the first metal film 40. The first metal film 40 is less prone to migration than the second metal film 30.

  A bonded metal film 50 is disposed between the support substrate 10 and the first metal film 40. As will be described later, the laminated metal film 50 is used as a bonding material for integrating the light emitting element 20 and the support substrate 10 together.

  As shown in FIG. 1, the periphery of the light emitting element 20, the first metal film 40, and the bonded metal film 50 is covered with a light-transmitting insulating protective film 100. The insulating protective film 100 contributes to suppression of moisture permeation into the light emitting element 20 from the outside and improvement in mechanical strength of the light emitting device. A light transmissive film 110 is disposed so as to cover the periphery of the insulating protective film 100.

  The light emitting element 20 has a stacked structure in which a second conductivity type second semiconductor layer 23 is disposed above the first conductivity type first semiconductor layer 21. The first semiconductor layer 21 covers the upper surface of the second metal film 30, and the lower surface of the first semiconductor layer 21 is in contact with the second metal film 30. The light emitting element 20 uses the upper surface of the second semiconductor layer 23 as a light extraction surface.

  The first conductivity type and the second conductivity type are opposite to each other. That is, if the first conductivity type is P type, the second conductivity type is N type, and if the first conductivity type is N type, the second conductivity type is P type. Hereinafter, a case where the first conductivity type is the P type and the second conductivity type is the N type will be described as an example.

  For example, the light emitting element 20 is an LED element in which the first semiconductor layer 21 is a P-type cladding layer and the second semiconductor layer 23 is an N-type cladding layer. In the light-emitting device shown in FIG. 1, a double hetero structure in which a first semiconductor layer 21, a light-emitting layer 22, and a second semiconductor layer 23 are stacked is employed for the light-emitting element 20.

  The first semiconductor layer 21 is electrically connected to the first electrode 61, and the second semiconductor layer 23 is electrically connected to the second electrode 62. The first electrode 61 and the second electrode 62 are electrodes for supplying a driving current for the light emitting element 20. Hereinafter, the first electrode 61 and the second electrode 62 are collectively referred to as “power supply electrode”. The power supply electrode is disposed on the side surface of the support substrate 10.

  As shown in FIG. 1, the first electrode wiring 71 disposed on the upper surface of the support substrate 10 is connected to the first semiconductor layer via the second metal film 30, the first metal film 40, and the bonded metal film 50. It is electrically connected to the lower surface of 21. The first electrode wiring 71 is drawn to the outside of the support substrate 10 and connected to the first electrode 61.

  The second semiconductor layer 23 and the second electrode 62 include a surface electrode 80 disposed on the upper surface of the second semiconductor layer 23 and a second electrode wiring 72 disposed on the side surface of the insulating protective film 100. Are electrically connected. The surface electrode 80 is disposed at the outer edge portion of the light extraction surface, and the end portion of the second electrode wiring 72 penetrating the insulating protective film 100 is connected to the surface electrode 80. By the insulating protective film 100, the first electrode wiring 71 and the second electrode wiring 72 are insulated and separated. Hereinafter, the first electrode wiring 71 and the second electrode wiring 72 are collectively referred to as “electrode wiring”.

  Holes are supplied from the first electrode 61 to the first semiconductor layer 21 through the first electrode wiring 71, the bonded metal film 50, the first metal film 40, and the second metal film 30. On the other hand, electrons are supplied from the second electrode 62 to the second semiconductor layer 23 through the second electrode wiring 72 and the surface electrode 80. Then, holes are injected from the first semiconductor layer 21 and electrons are injected from the second semiconductor layer 23 into the light emitting layer 22. The injected holes and electrons recombine in the light emitting layer 22 to generate light in the light emitting layer 22. Light emitted from the light emitting element 20 passes through the light transmissive film 110 and is output as output light L from the light emitting device.

  At this time, the emitted light traveling in the direction from the light emitting element 20 toward the first semiconductor layer 21 is reflected on the surface of the second metal film 30. That is, the second metal film 30 can reflect the emitted light of the light emitting element 20 traveling in the direction opposite to the light extraction surface toward the light extraction surface. For this reason, the brightness of the output light L can be improved.

  The second metal film 30 is made of a conductive material having a higher reflectance with respect to the emitted light of the light emitting element 20 than the first metal film 40 and capable of making ohmic contact with the first semiconductor layer 21. For example, a white metal film such as a silver-based alloy such as a silver-palladium alloy, an aluminum (Al) film, a dielectric multilayer film (DBR), or the like is preferably used as the material of the second metal film 30.

  However, the material used for the second metal film 30 is a metal that easily undergoes migration. When migration occurs in the second metal film 30, the reliability of the light emitting device is lowered.

  In contrast, in the light emitting device shown in FIG. 1, the side surface of the second metal film 30 is below the outer edge portion of the light emitting element 20 so that the outer edge portion of the second metal film 30 is not exposed to the outside. 40. Furthermore, the bottom surface of the second metal film 30 is covered with the first metal film 40 so that the second metal film 30 does not come into contact with the bonded metal film 50. The first metal film 40 is less likely to cause migration than the second metal film 30. As a result, a decrease in reliability of the light emitting device is suppressed. For the first metal film 40, a material that is unlikely to cause migration, such as Au, titanium (Ti), and tungsten (W), is preferably used.

  By the way, in the light emitting device having the CSP structure, since the power supply electrode that shields the light from the light emitting element 20 is not arranged in the direction of the light extraction surface, the light emission efficiency of the light emitting device is improved. Moreover, since wire bonding is not used for the connection between the light emitting element and the power supply electrode, it is possible to suppress problems such as disconnection of the wire and short circuit through the wire. Therefore, the reliability of the light emitting device is improved.

  However, a light emitting device having a CSP structure has a low mechanical strength when a transparent resin such as an epoxy resin or a silicone resin is used for a portion from which light is extracted. For this reason, the mechanical strength of the whole package falls.

  Further, the stress applied to the light emitting element 20 greatly affects the characteristics of the light emitting device. In particular, in the case of a light emitting device having a CSP structure, the light emitting element 20 is bonded to the support substrate 10 made of a package material. 20 is easily stressed. When stress is applied to the light emitting element 20, the reliability of the light emitting device is lowered and the light emission efficiency is lowered.

  Further, when the power supply electrode is disposed below the light emitting element 20 through the support substrate 10, the light emitting element 20 is supported from below by the support substrate 10 and the power supply electrode. In this case, the light emitting element 20 is distorted due to a difference in coefficient of linear expansion between the support substrate 10 and the power supply electrode.

  However, in the light emitting device illustrated in FIG. 1, the entire lower surface of the light emitting element 20 is covered with the support substrate 10 in plan view, and the first electrode 61 and the second electrode 62 are disposed outside the light emitting element 20. ing. That is, the support substrate 10 is disposed below the light emitting element 20 between the first electrode 61 and the second electrode 62. For this reason, there is no boundary between the support substrate 10 and the power supply electrode below the light emitting element 20. Therefore, according to the light emitting device shown in FIG. 1, the occurrence of distortion in the light emitting element 20 due to the difference in linear expansion coefficient between the support substrate 10 and the power supply electrode is suppressed.

  For the support substrate 10, an epoxy resin or a silicone resin containing a filler can be used. Moreover, the white support substrate 10 is realizable by adding a white pigment to these resin. According to the white support substrate 10, the reflectance at the support substrate 10 can be improved. As a result, the luminance of the light emitting device is improved.

  Further, a material having higher mechanical strength than the resin may be used for the support substrate 10. For example, a ceramic substrate is used for the support substrate 10. By using a ceramic substrate having a high mechanical strength for the support substrate 10, the mechanical strength as a package of the light emitting device can be improved.

  As described above, in the light emitting device according to the embodiment of the present invention, the first metal film 40 is disposed so as to cover the side surface and the bottom surface of the second metal film 30. Thereby, the occurrence of migration in the second metal film 30 is suppressed by the first metal film 40. For this reason, the fall of the reliability of a light-emitting device is suppressed. In addition, an inexpensive resin substrate or ceramic substrate can be used as the support substrate 10, and the light emitting element 20 is supported from below by a uniform material. For this reason, breakage of the light emitting device is prevented, and a decrease in performance of the light emitting device and a decrease in product life are suppressed. Therefore, according to the light-emitting device shown in FIG. 1, it is possible to provide a light-emitting device having a CSP structure that is inexpensive and highly reliable.

  In the light emitting device shown in FIG. 1, the surface electrode 80 is arranged on the light extraction surface. For this reason, unlike the case where the second electrode wiring 72 is disposed on the lower surface of the light emitting element 20, it is not necessary to expose the second semiconductor layer 23 on the lower surface of the light emitting element 20. Thereby, the area of the first semiconductor layer 21 can be made as large as that of the second semiconductor layer 23. As a result, the series resistance of the light emitting device is reduced, and a reliable light emitting device with high yield can be realized. In addition, the area of the surface electrode 80 can be set very small compared with the whole area of the light extraction surface of the light emitting element 20. For this reason, the fall of the light extraction efficiency by having arrange | positioned the surface electrode 80 is small.

  For the surface electrode 80, for example, an Au film or the like is used. Alternatively, a transparent electrode may be used for the surface electrode 80. For example, by using a transparent electrode such as a ZnO film or an ITO film for the surface electrode 80, a decrease in light extraction efficiency can be suppressed.

  The light transmissive film 110 functions as a sealing material for the light emitting element 20 and a lens of the light emitting device. For example, a thermoplastic resin or a thermosetting resin can be used for the light transmissive film 110. By using a transparent resin for the light transmissive film 110, the output light L having the same color as the light emitted from the light emitting element 20 can be output from the light emitting device.

  Alternatively, a phosphor resin containing a phosphor that is excited by the light emitted from the light emitting element 20 to emit excitation light may be used for the light transmissive film 110. By using a phosphor resin for the light transmissive film 110, output light L having a desired color can be output from the light emitting device. Moreover, it is also possible to output the output light L in which the light emitted from the light emitting element 20 and the excitation light are mixed from the light emitting device.

  As a transparent resin used for the light transmissive film 110, an epoxy resin, a modified epoxy resin, a silicone resin, a modified silicone resin, or the like can be used. For example, in a high-power light-emitting device such as a lighting application, a silicone resin having high heat resistance is used. Moreover, what mixed the fluorescent material in the said transparent resin etc. can be used as fluorescent substance resin.

  Below, with reference to FIGS. 2-6, the manufacturing method of the light-emitting device which concerns on embodiment of this invention is demonstrated. Note that the manufacturing method of the light-emitting device described below is an example, and it is needless to say that it can be realized by various other manufacturing methods including this modification.

  First, as shown in FIG. 2, each layer constituting the light emitting element 20 is formed on a semiconductor substrate 200 having a thickness of about 700 μm by an epitaxial growth method or the like. That is, the second semiconductor layer 23, the light emitting layer 22, and the first semiconductor layer 21 are sequentially stacked on the semiconductor substrate 200. For the second semiconductor layer 23, the light emitting layer 22, and the first semiconductor layer 21, a nitride compound semiconductor layer such as gallium nitride is used.

  Next, the second metal film 30 is formed so as to be in contact with the first semiconductor layer 21. At this time, the second metal film 30 is patterned so that the outer edge portion of the second metal film 30 is located inside the outer edge portion of the first semiconductor layer 21. Next, the first metal film 40 is formed on the surface of the second metal film 30 so as to cover the exposed surface of the second metal film 30. Thereafter, as shown in FIG. 3, an element-side bonded metal film 51 is formed on the surface of the first metal film 40.

  On the other hand, as shown in FIG. 4, the support substrate 10 having the first electrode wiring 71 and the substrate-side bonded metal film 52 formed on the upper surface is prepared. The support substrate 10 is, for example, a resin substrate, and has a region where the first electrode 61 and the second electrode 62 are formed on the side surface. The first electrode wiring 71 and the substrate-side bonded metal film 52 are disposed in a region sandwiched between the first electrode 61 and the second electrode 62. At this time, the end portion of the first electrode wiring 71 is connected to the first electrode 61.

  The first electrode 61 and the second electrode 62 are formed by, for example, copper (Cu) plating. The material of the power supply electrode is selected in consideration of the overall strength of the light emitting device. In addition to Cu plating, an Al material or the like may be used for the power supply electrode.

  Etching is performed by a back grinding process in which the surface of the support substrate 10 is polished in the film thickness direction until the thickness of the support substrate 10 reaches a predetermined value. As a result, as shown in FIG. 4, the lower surfaces of the first electrode 61 and the second electrode 62 are exposed below the lower surface of the support substrate 10.

  Then, as shown in FIG. 5, the element-side bonded metal film 51 and the substrate-side bonded metal film 52 are bonded to integrate the light emitting element 20 and the support substrate 10.

  Next, the semiconductor substrate 200 is deleted from the light emitting element 20. For example, when the semiconductor substrate 200 is a silicon substrate, the semiconductor substrate 200 is deleted by wet etching using hydrofluoric acid. When the semiconductor substrate 200 is a sapphire substrate, a laser lift-off method or the like is used.

  Thereafter, as shown in FIG. 6, an insulating protective film 100 is formed so as to cover the base disposed on the surface of the support substrate 10. That is, the periphery of the light emitting element 20, the first metal film 40, the bonded metal film 50, and the first electrode wiring 71 is covered with the light-transmitting insulating protective film 100.

  Then, an opening of the insulating protective film 100 is formed above the light emitting element 20, and the surface electrode 80 is formed on the upper surface of the second semiconductor layer 23 exposed in the opening. Further, the second electrode wiring 72 is formed so as to fill the opening of the insulating protective film 100. As shown in FIG. 6, the second electrode wiring 72 having one end connected to the surface electrode 80 is formed from the upper surface of the insulating protective film 100 so that the other end is connected to the second electrode 62. Arranged across the side. Note that a gold (Au) film or the like is used for the electrode wiring, but an aluminum (Al) film or a silver (Ag) film is also used.

  Next, as shown in FIG. 6, a first connection electrode 91 is formed so as to cover the lower surface of the first electrode 61, and a second connection electrode 92 is formed so as to cover the lower surface of the second electrode 62. Form. The first connection electrode 91 and the second connection electrode 92 (hereinafter collectively referred to as “connection electrode”) are arranged on the mounting substrate when the light emitting device is attached to the mounting substrate such as a printed circuit board. The wiring pattern is used to connect the power supply electrode of the light emitting device. A solder electrode or the like is preferably used as the connection electrode.

  Thereafter, a light transmissive film 110 is formed on the support substrate 10 and the power supply electrode. Then, a singulation process for separating the light emitting devices individually by dicing is performed. Thus, the light emitting device shown in FIG. 1 is completed.

  A structure in which the element-side bonded metal film 51 and the substrate-side bonded metal film 52 are bonded together is the bonded metal film 50 shown in FIG. That is, in the above manufacturing method, the element-side bonded metal film 51 and the substrate-side bonded metal film 52 are bonded together in order to integrate the support substrate 10 and the light emitting element 20.

  A metal used as a barrier metal or a metal used for bonding can be used for the bonded metal film 50. For example, metals such as Ti, Au, Sn, nickel (Ni), chromium (Cr), gallium (Ga), indium (In), bismuth (Bi), Cu, Ag, and tantalum (Ta), or alloys thereof, Used for the laminated metal film 50. The element-side bonded metal film 51 and the substrate-side bonded metal film 52 may be made of the same material or different materials.

  In addition, by using a material having a melting point lower than that of Au, such as solder or tin (Sn), for the laminated metal film 50, the support substrate 10 and the light emitting element 20 are integrated with each other at a temperature of 300 ° C. or less and in a short time. Can be For example, AuSn is used for the element-side bonded metal film 51 and the substrate-side bonded metal film 52.

  According to the light emitting device manufacturing method according to the embodiment of the present invention as described above, a light emitting device in which the occurrence of migration in the second metal film 30 is suppressed can be realized. Moreover, the structure where the whole light emitting element 20 is supported by the support substrate 10 from the downward direction is realizable. For this reason, it is suppressed that the stress by distortion is added to the light emitting element 20.

  In the light emitting device having the CSP structure, since the package is in contact with the light emitting element 20, the mechanical strength of the light emitting element 20 can be reinforced to realize a highly reliable light emitting device. Further, since the semiconductor substrate 200 is removed during the manufacturing process, the height of the light emitting device can be reduced. Furthermore, removal of the semiconductor substrate 200 improves the light extraction efficiency from the light emitting element 20.

  In the above manufacturing method, the example in which the support substrate 10 is a resin substrate has been described. However, it is preferable to use a material having higher mechanical strength than the resin for the support substrate 10. This is because in the light emitting device having the CSP structure, the semiconductor substrate 200 is omitted, and a material having low mechanical strength such as epoxy resin or silicone resin is used for the light transmissive film 110, so that the mechanical strength of the entire package is low. .

  If the mechanical strength of the package is low, there is a risk that the light emitting device may be damaged when it is incorporated into the product substrate or after it is incorporated. In addition, it is necessary to take measures such as devising the configuration of the built-in device or slowing down the built-in speed so that the light emitting device is not damaged.

  Therefore, it is preferable to increase the mechanical strength of the entire package by using a material having high mechanical strength for the support substrate 10. For example, using a ceramic substrate for the support substrate 10 is effective in increasing the mechanical strength of the light emitting device. In order to use the support substrate 10 as a ceramic substrate, for example, a liquid ceramic material is formed into a predetermined shape and then baked at a high temperature.

  By using a ceramic substrate for the support substrate 10, the mechanical strength of the light emitting device is improved. Furthermore, since the ceramic substrate is disposed so as to support substantially the entire lower surface of the light emitting element 20, it is possible to prevent the light emitting element 20 from being damaged due to distortion during manufacturing in the process of removing the semiconductor substrate 200 or the like. Further, it is possible to prevent the light emitting element 20 from being damaged by an impact applied to the light emitting device during product assembly or handling. As described above, by using the support substrate 10 as the ceramic substrate, it is possible to suppress damage to the light emitting device and deterioration of reliability. In addition, it is possible to suppress damage due to thermal distortion caused by solder heat treatment during product assembly.

  However, in the case of a ceramic substrate, the back grinding process after forming the ceramic substrate and the singulation process by dicing are difficult compared to the resin substrate. Therefore, as described with reference to FIG. 4, the support substrate 10 is formed so that the lower surface of the first electrode 61 and the lower surface of the second electrode 62 are located below the lower surface of the support substrate 10. To do. For example, the step between the lower surface of the support substrate 10 and the lower surface of the power supply electrode is set to about 10 μm. Thereby, the polishing process of the ceramic substrate after the ceramic substrate is formed as the support substrate 10 becomes unnecessary. For this reason, the damage which the polishing process gives to the support substrate 10 and the light emitting element 20 can be reduced. As a result, a decrease in yield and reliability of the light emitting device can be suppressed.

  Furthermore, it is preferable that the power supply electrode is disposed so as to penetrate the support substrate 10 at a location where the dicing blade passes in dicing for singulation processing. As a result, the power supply electrode is mainly cut from the support substrate 10 by the dicing blade. For this reason, the processing time of dicing when a ceramic substrate is used is reduced. Further, since the life of the dicing blade is extended, the manufacturing cost can be reduced.

  In addition, since the hardness of metal is lower than that of ceramic, distortion at the time of cutting is relieved by the metal power electrode. For this reason, the damage given to the light emitting element 20 is relieved, and a light emitting device with high yield and high reliability can be realized.

  In the light-emitting device shown in FIG. 1, the power electrode is disposed on the side surface of the support substrate 10, and the above-described effect can be obtained by mainly cutting the power electrode in dicing.

<First Modification>
As already described, the stress applied to the light emitting element 20 greatly affects the characteristics of the light emitting device. In particular, since the light emitting device having the CSP structure has a structure in which the light emitting element 20 is in close contact with the package material, stress is easily applied to the light emitting element 20 due to a difference in linear expansion coefficient from the package material or deformation during processing.

  Therefore, as shown in FIG. 7, the first ceramic layer 11 and the second ceramic layer 12 having a higher density and a larger linear expansion coefficient than the first ceramic layer 11 are laminated on the support substrate 10. A ceramic substrate having a structure may be used. As shown in FIG. 7, the first ceramic layer 11 having a low linear expansion coefficient and a low density is disposed on the side close to the light emitting element 20. That is, the first ceramic layer 11 having a linear expansion coefficient close to that of the semiconductor layer constituting the light emitting element 20 is disposed on the side close to the light emitting element 20. Thereby, the distortion at the time of hardening a ceramic is relieved and the stress added to the light emitting element 20 can be reduced.

  Further, the second ceramic layer 12 having a large linear expansion coefficient is provided on the side of the support substrate 10 that is far from the light emitting element 20, so that the warp of the support substrate 10 is suppressed and the strength of the entire package is prevented from being lowered. it can. Therefore, by using the support substrate 10 having the structure shown in FIG. 7, a highly reliable and highly efficient light-emitting device can be realized. In order to reduce the linear expansion coefficient and the elastic coefficient of the first ceramic layer 11, for example, there is a method of mixing a filler or increasing the porosity.

  In order to laminate the first ceramic layer 11 and the second ceramic layer 12, for example, a method in which two ceramic sheets (green sheets) having different linear expansion coefficients are bonded to each other, or two coating ceramics are used. The method of layering can be used. Thus, the first ceramic layer 11 and the second ceramic layer 12 can be formed by an inexpensive method.

  In addition, when a glass substrate is used for the light transmissive film 110, the glass substrate has a high elastic coefficient and a large linear expansion coefficient, so that a large stress is generated in the light emitting element 20. In this case, the linear expansion coefficient of the first ceramic layer 11 can be made closer to glass by making the linear expansion coefficient of the first ceramic layer 11 smaller than that of the second ceramic layer 12. Thereby, the stress added to the light emitting element 20 can be reduced.

<Second Modification>
When the electrode wiring is arranged on the upper surface of the support substrate 10, the light reflection function by the support substrate 10 is hindered. For this reason, it is preferable that the upper surface of the support substrate 10 is exposed outside the light emitting element 20 in plan view.

  For example, as shown in FIG. 8, a part of the upper portion of the support substrate 10 is extended above the first electrode 61 and above the second electrode 62. That is, the first electrode 61 and the second electrode 62 are disposed below the upper surface of the support substrate 10. At this time, the first electrode wiring 71 and the second electrode wiring 72 have a portion that passes through the inside of the support substrate 10 outside the light emitting element 20 in a plan view. Thereby, the emitted light of the light emitting element 20 is reflected on the exposed upper surface of the support substrate 10.

  The light emitting device shown in FIG. 8 has a structure in which a part of the first electrode wiring 71 and the second electrode wiring 72 is disposed between the first ceramic layer 11 and the second ceramic layer 12. That is, the first electrode wiring 71 connected to the end portion of the bonded metal film 50 has the first ceramic layer extending from the light emitting element 20 to the boundary between the first ceramic layer 11 and the second ceramic layer 12 in a plan view. 11 is stretched in the film thickness direction. The end portion of the first electrode wiring 71 extending along the boundary between the first ceramic layer 11 and the second ceramic layer 12 is connected to the first electrode 61. In addition, the second electrode wiring 72 disposed on the side surface of the insulating protective film 100 has the first ceramic extending from the light emitting element 20 to the boundary between the first ceramic layer 11 and the second ceramic layer 12 in a plan view. It extends through the layer 11 in the film thickness direction. Then, the end of the second electrode wiring 72 extending along the boundary between the first ceramic layer 11 and the second ceramic layer 12 is connected to the second electrode 62.

  By passing the first electrode wiring 71 and the second electrode wiring 72 through the inside of the support substrate 10 as described above, the light emitted from the light emitting element 20 is reflected on the exposed upper surface of the support substrate 10. Thereby, the brightness | luminance of a light-emitting device improves.

  Furthermore, by arranging the first electrode wiring 71 inside the support substrate 10, the first electrode wiring 71 is not arranged below the light emitting element 20. For this reason, the stress added to the light emitting element 20 is suppressed.

  Even in the case of the support substrate 10 not having a structure in which ceramic layers are laminated, the upper surface of the support substrate 10 is exposed by disposing the first electrode wiring 71 and the second electrode wiring 72 inside the support substrate 10. Can be made.

<Third Modification>
FIG. 1 illustrates an example in which the second semiconductor layer 23 and the second electrode 62 are electrically connected via the surface electrode 80 disposed on the upper surface of the second semiconductor layer 23 of the light emitting element 20. On the other hand, in the light emitting device shown in FIG. 9, the second electrode wiring 72 that connects the second semiconductor layer 23 and the second electrode 62 is electrically connected to the lower surface of the second semiconductor layer 23. Has been.

  As shown in FIG. 9, the second semiconductor layer 23 has an extending region that extends in the horizontal direction to a region where the first semiconductor layer 21 and the light emitting layer 22 are not disposed in a plan view. The second electrode wiring 72 is connected to the lower surface of the extended region of the second semiconductor layer 23.

  In the light emitting device shown in FIG. 9, the light emitted from the light emitting element 20 is emitted from the entire surface of the light extraction surface. For this reason, an effective light extraction surface can be widened.

(Other embodiments)
As mentioned above, although this invention was described by embodiment, it should not be understood that the description and drawing which form a part of this indication limit this invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  In the above, an example in which the support substrate 10 and the light emitting element 20 are integrated by the bonded metal film 50 has been described. However, the bonded metal film 50 may not be used. That is, as shown in FIG. 10, the first electrode wiring 71 and the first metal film 40 are directly bonded to each other so that the bonded metal film 50 is not disposed between the support substrate 10 and the light emitting element 20. A device is feasible. Further, instead of the laminated metal film 50, a resin adhesive having conductivity may be used.

  In the light emitting device shown in FIG. 10 as well, the electrode wiring may be passed through the support substrate 10 as shown in FIG.

  As described above, the present invention naturally includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

  The semiconductor device of the present invention can be used for a light-emitting device having a CSP structure.

Claims (6)

And supporting lifting the substrate,
A first metal film disposed on the support substrate;
A second metal film embedded in a part of the upper part of the first metal film and having side and bottom surfaces covered with the first metal film;
A light emitting device disposed on the first metal film so as to cover an upper surface of the second metal film;
The support substrate is a ceramic substrate,
The ceramic substrate is
A first ceramic layer;
A second ceramic layer having a larger linear expansion coefficient than the first ceramic layer;
Have a laminated structure,
The first ceramic layer is disposed on a side close to the light emitting element;
The second metal film has a higher reflectance with respect to the emitted light of the light emitting element than the first metal film,
The CSP structure light-emitting device, wherein the first metal film is less likely to cause migration than the second metal film.   The light emitting device according to claim 1, further comprising a bonded metal film disposed between the support substrate and the first metal film. The light-emitting element has a stacked structure in which a second semiconductor layer is disposed above a first semiconductor layer,
A first electrode electrically connected to the first semiconductor layer;
A second electrode electrically connected to the second semiconductor layer,
2. The plan view of claim 1, wherein the lower surface of the light emitting element is entirely covered with the support substrate, and the first electrode and the second electrode are respectively disposed outside the light emitting element. The light emitting device according to 1. A first electrode wiring for electrically connecting the first semiconductor layer and the first electrode;
A second electrode wiring for electrically connecting the second semiconductor layer and the second electrode;
The first electrode wiring and the second electrode wiring have a portion that passes through the inside of the support substrate outside the light emitting element in a plan view;
The light emitting device according to claim 3 , wherein an upper surface of the support substrate is exposed outside the light emitting element. The light-emitting device according to claim 4 , wherein a part of the upper portion of the support substrate extends above the first electrode and above the second electrode. The said 2nd semiconductor layer and the said 2nd electrode are electrically connected through the surface electrode arrange | positioned at the upper surface of the said 2nd semiconductor layer, The Claim 3 characterized by the above-mentioned. Light emitting device.

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