semiconductor light-emitting devices

Abstract

The present invention provides a semiconductor light-emitting device. The device comprises: a semiconductor light-emitting element; a substrate on which the semiconductor light-emitting element is mounted and having a substrate bonding surface, to which an annular substrate metal layer is fixed; a light-transmitting cover made of glass and having a window portion and a flange, wherein the window portion allows light emitted by the semiconductor light-emitting element to pass through; a flange having an annular flange fixing layer fixed to its bottom surface, the flange fixing layer having a size corresponding to the substrate metal layer, and being bonded to the substrate metal layer to form a space for accommodating the semiconductor light-emitting element; and the light-transmitting cover is hermetically bonded to the substrate. The flange fixing layer is composed of a ceramic layer fused to the flange and a metal layer formed on the ceramic layer.

Description

Technical Field

[0001] The present invention relates to a semiconductor light emitting device, and more particularly to a semiconductor light emitting device having a semiconductor light emitting element that radiates ultraviolet light sealed therein. Background Art

[0002] Conventionally, semiconductor devices are known that enclose semiconductor elements within a semiconductor package. In the case of a semiconductor light-emitting module, a transparent window member such as glass that transmits light from the light-emitting element is bonded to a support on which the semiconductor light-emitting element is mounted, thereby forming an airtight seal.

[0003] For example, Patent Documents 1 and 2 disclose a semiconductor light emitting module in which a substrate and a window member are bonded together, wherein the substrate is provided with a recess for accommodating a semiconductor light emitting element.

[0004] Patent Documents 3 and 4 disclose an ultraviolet light emitting device in which a mounting substrate on which an ultraviolet light emitting element is mounted, a spacer, and a cover formed of glass are bonded together.

[0005] Patent Document 5 discloses quartz glass having a surface coated with a ceramic thermal spray coating and the adhesion of the thermal spray coating on the ceramic.

[0006] Furthermore, ceramic thermal spraying techniques are disclosed in Non-Patent Documents 1 and 2. Non-Patent Document 3 discloses black alumina-based ceramics "black alumina (AR(B))".

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Laid-Open No. 2015-18873

[0010] Patent Document 2: Japanese Patent Application Publication No. 2018-93137

[0011] Patent Document 3: Japanese Patent Application Laid-Open No. 2016-127255

[0012] Patent Document 4: Japanese Patent Application Laid-Open No. 2016-127249

[0013] Patent Document 5: Japanese Patent Application Laid-Open No. 2003-212598

[0014] Non-patent literature

[0015] Non-patent document 1: Japan Thermal Spraying Society, http: / / www.jtss.or.jp / about_ts-j.htm

[0016] Non-Patent Literature 2: Kazuo Ueno, "JIS H8304 Ceramic Spraying Revision 2014," http: / / www.jtss.or.jp / journal / 8304review.pdf

[0017] Non-patent document 3: ASUZAC Co., Ltd.

[0018] http: / / www.asuzac-ceramics.jp / technology / tech15.htm Summary of the Invention

[0019] Problems to be solved by the invention

[0020] However, there is a need to further improve the sealing and bonding reliability between the substrate and the window member. Ultraviolet-emitting semiconductor light-emitting elements, particularly AlGaN-based semiconductor light-emitting elements, are susceptible to degradation if their airtightness is insufficient. Therefore, semiconductor devices equipped with these semiconductor light-emitting elements require high airtightness.

[0021] Furthermore, AlGaN crystals are degraded by moisture. In particular, degradation is more likely to occur as the emission wavelength shortens, increasing the Al content. Therefore, to create an airtight structure that prevents moisture from entering the package housing the light-emitting element, a metal bonding material is used to create an airtight seal between the substrate and the glass cover. However, this still presents the problem of insufficient airtightness when used in humid environments or where water is present.

[0022] In addition, there is also a problem that glass such as quartz that transmits ultraviolet light or deep ultraviolet light has high glass purity and hardness and poor adhesion to metals.

[0023] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a semiconductor light-emitting device having high reliability and high environmental resistance such as high moisture resistance and high corrosion resistance, which can maintain high airtightness even during long-term use.

[0024] Means for solving problems

[0025] A semiconductor light emitting device according to a first embodiment of the present invention includes:

[0026] Semiconductor light emitting element;

[0027] a substrate on which the semiconductor light emitting element is mounted and which has a substrate bonding surface, to which a ring-shaped substrate metal layer is fixed; and

[0028] a light-transmitting cover made of glass and having a window portion and a flange, wherein the window portion allows light emitted by the semiconductor light-emitting element to pass through; the flange having an annular flange fixing layer fixed to its bottom surface, the flange fixing layer having a size corresponding to the substrate metal layer; the flange fixing layer is bonded to the substrate metal layer to form a space for accommodating the semiconductor light-emitting element; and the light-transmitting cover is sealed to the substrate;

[0029] The flange fixing layer is composed of a ceramic layer welded to the flange and a metal layer formed on the ceramic layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1A It is a plan view schematically showing the upper surface of the semiconductor light emitting device 10 according to the first embodiment.

[0031] Figure 1B It is a diagram schematically showing a side view of the semiconductor light emitting device 10 .

[0032] Figure 1C It is a plan view schematically showing the back surface of the semiconductor light emitting device 10 .

[0033] Figure 1D 1 is a diagram schematically showing the internal structure of the semiconductor light emitting device 10 .

[0034] Figure 1E It is a perspective view schematically showing a 1 / 4 portion of the light-transmitting cover 13 according to the first embodiment.

[0035] Figure 2A It is a schematic representation of the Figure 1A AA line is a cross-sectional view of the semiconductor light emitting device 10 .

[0036] Figure 2B It is an enlarged representation Figure 2A A partially enlarged cross-sectional view of the cross section of the joining portion (W portion).

[0037] Figure 3A This is a partially enlarged cross-sectional view showing a part of the flange 13B and the flange fixing layer 21 in an enlarged manner when a white alumina layer is used as the ceramic layer 21C.

[0038] Figure 3B This is a partially enlarged cross-sectional view showing a part of the flange 13B and the flange fixing layer 21 in an enlarged manner when black alumina is used as the ceramic layer 21C.

[0039] Figure 4A It is a cross-sectional view schematically showing a cross section of a semiconductor light emitting device 30 according to the second embodiment of the present invention.

[0040] Figure 4BIt is an enlarged representation Figure 4A A partially enlarged cross-sectional view of the joining portion (W portion).

[0041] Figure 5A This is a partially enlarged cross-sectional view showing a case where the ceramic layer 21C is a light-reflective ceramic layer 21C(W).

[0042] Figure 5B This is a partially enlarged cross-sectional view showing a case where the ceramic layer 21C is a light-absorbing ceramic layer 21C (B).

[0043] Figure 5C This is a partially enlarged cross-sectional view showing a case where the ceramic layer 21C is composed of a light-absorbing ceramic layer 21C(B) and a light-reflecting ceramic layer 21C(W) (two-layer structure).

[0044] Figure 6 This is a partially enlarged cross-sectional view schematically showing a case where the top surface height of the ceramic layer inner peripheral portion 21P is higher than the height of the upper surface 13F of the flange 13B.

[0045] Figure 7 This is a schematic partial enlarged cross-sectional view showing an enlarged cross section of a portion of the flange 13B and the flange fixing layer 21 in a modified example of the second embodiment.

[0046] Explanation of symbols

[0047] 10, 30: semiconductor light-emitting device;

[0048] 11: Substrate;

[0049] 12: substrate metal layer;

[0050] 12S: substrate bonding surface;

[0051] 13: light-transmitting cover;

[0052] 13A: Window;

[0053] 13B: flange;

[0054] 15: semiconductor light emitting element;

[0055] 21: flange fixing layer;

[0056] 21C, 21C(W), 21C(B): ceramic layer;

[0057] 21M: Metal layer (flange metal layer);

[0058] 21P: Inner periphery of ceramic layer. DETAILED DESCRIPTION

[0059] [First embodiment]

[0060] Figure 1A It is a plan view schematically showing the upper surface of the semiconductor light emitting device 10 in the first embodiment of the present invention. Figure 1B It is a diagram schematically showing a side view of the semiconductor light emitting device 10 . Figure 1C It is a plan view schematically showing the back surface of the semiconductor light emitting device 10 . Figure 1D 1 is a diagram schematically showing the internal structure of the semiconductor light emitting device 10 . Figure 1E It is a perspective view schematically showing a 1 / 4 portion of the light-transmitting cover 13 .

[0061] in addition, Figure 2A It schematically shows the Figure 1A The cross section of the semiconductor light emitting device 10 taken along line AA. Figure 2B It will Figure 2A A partially enlarged cross-sectional view showing an enlarged cross-section of the joining portion (W portion).

[0062] like Figure 1A and Figure 1B As shown, semiconductor light-emitting device 10 is constructed by bonding a rectangular substrate 11 to a translucent cover 13. Translucent cover 13 is a translucent window made of hemispherical glass. More specifically, a ring-shaped metal layer 12 (hereinafter referred to as substrate metal layer 12) is formed on the upper surface of substrate 11 and bonded to translucent cover 13.

[0063] Note that the semiconductor light emitting device 10 is shown in a manner such that the side surfaces of the substrate 11 are parallel to the x-direction and the y-direction and the upper surface of the substrate 11 is parallel to the xy plane.

[0064] like Figure 1E and Figure 2A As shown, the light-transmitting cover 13 is composed of a hemispherical dome portion 13A serving as a window portion and a flange portion (hereinafter referred to as a flange) 13B provided at the end of the bottom of the dome portion 13A. In other words, the light-transmitting cover 13 is composed of the dome portion 13A (window portion) and the flange 13B being airtightly joined.

[0065] exist Figure 2B The flange 13B, the ceramic layer 21C welded to the flange 13B, and the metal layer (flange metal layer) 21M fixed to the ceramic layer 21C are shown in enlarged form. In this specification, unless otherwise specified, the layer consisting of the ceramic layer 21C and the metal layer 21M is collectively referred to as the flange fixing layer 21. The flange 13B has a circular plate shape.

[0066] The substrate 11 is a ceramic substrate that is impermeable to gases and the like. For example, aluminum nitride (AlN) having high thermal conductivity and excellent airtightness is used for the substrate 11. The thermal conductivity of AlN ceramics is 150 to 170 (W / m·K) and the thermal expansion coefficient is 4.5 to 4.6 (10 -6 ·K -1 ).

[0067] It should be noted that the substrate 11 may be made of silicon carbide (SiC) with high thermal conductivity or white alumina (Al2O3) with high reflectivity. The thermal conductivity of SiC is 200 (W / m·K) and the thermal expansion coefficient is 4.4 (10 -6 ·K -1 ); the thermal conductivity of Al2O3 is 29-32 (W / m·K), and the thermal expansion coefficient is 7.7-8 (10 -6 ·K -1 ).

[0068] The light-transmitting cover 13 is made of light-transmitting glass and transmits the light emitted by the light-emitting element 15 disposed in the semiconductor light-emitting device 10. For example, quartz glass or borosilicate glass can be appropriately used as the light-transmitting cover 13.

[0069] As the enclosed gas in the semiconductor light emitting device 10 , dry nitrogen, air with a low oxygen content ratio, or the like may be used, or the interior may be set to a vacuum.

[0070] like Figure 1D As shown, substrate 11 includes a first wiring electrode (e.g., an anode electrode) 14A and a second wiring electrode (e.g., a cathode electrode) 14B (hereinafter, collectively referred to as wiring electrodes 14 unless otherwise specified) serving as wiring electrodes within semiconductor light-emitting device 10. A semiconductor light-emitting element 15, such as a light-emitting diode (LED) or a semiconductor laser, is bonded to first wiring electrode 14A via a metal bonding layer 15A. A bonding pad 15B of light-emitting element 15 is electrically connected to second wiring electrode 14B via a bonding wire 18C.

[0071] Light-emitting element 15 is an aluminum gallium nitride (AlGaN)-based semiconductor light-emitting element (LED). It is formed as a semiconductor structure layer comprising an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer. The semiconductor structure layer of light-emitting element 15 is formed on a conductive supporting substrate (silicon: Si) with a reflective layer interposed therebetween.

[0072] The light-emitting element 15 includes an anode electrode (not shown) on the surface of the support substrate opposite to the surface bonded to the semiconductor structure layer (also referred to as the back surface of the light-emitting element 15), and is electrically connected to the first wiring electrode 14A on the substrate 11. Furthermore, the light-emitting element 15 includes a cathode electrode (bonding pad 15B) on the surface of the semiconductor structure layer opposite to the surface bonded to the support substrate (also referred to as the front surface of the light-emitting element 15), and is electrically connected to the second wiring electrode 14B via a bonding wire.

[0073] The light emitting element 15 may be an aluminum nitride-based light emitting element that emits ultraviolet light with a wavelength of 265 to 415 nm. Specifically, the light emitting element 15 may have a central emission wavelength of 265 nm, 275 nm, 355 nm, 365 nm, 385 nm, 405 nm, or 415 nm.

[0074] The semiconductor crystals that make up the aluminum nitride-based ultraviolet-emitting light-emitting elements (UV-LED elements) have a high Al content and are easily oxidized by oxygen (O2) and water (H2O), causing degradation. It should be noted that when a bonding member containing an organic substance such as flux is used to bond the first wiring electrode 14A to the light-emitting element 15, residual flux (organic matter) in the bonding member may cause carbide accumulation on the surface of the light-emitting element. However, this can be prevented by mixing a small amount of O2 into the sealed gas. In this case, the O2 is inactivated before the light-emitting element 15 degrades, so there is no problem.

[0075] Furthermore, a protection element 16 is provided on the substrate 11 . The protection element 16 is a Zener diode (ZD) connected to the first wiring electrode 14A and the second wiring electrode 14B, and is used to prevent electrostatic damage to the light emitting element 15 .

[0076] like Figure 1C As shown, a first mounting electrode 17A and a second mounting electrode 17B (hereinafter, collectively referred to as mounting electrodes 17 unless otherwise specified) are provided on the back surface of substrate 11. First mounting electrode 17A is connected to first wiring electrode 14A, and second mounting electrode 17B is connected to second wiring electrode 14. Specifically, first wiring electrode 14A and second wiring electrode 14 are connected to first mounting electrode 17A and second mounting electrode 17B via metal vias 18A and 18B, respectively (hereinafter, collectively referred to as metal vias 18 unless otherwise specified).

[0077] The wiring electrodes 14 , the mounting electrodes 17 , and the metal vias 18 are each made of, for example, tungsten / nickel / gold (W / Ni / Au) or nickel-chromium alloy / gold / nickel / gold (NiCr / Au / Ni / Au).

[0078] Reference Figure 2ASemiconductor light-emitting device 10 is configured to be mounted on a printed circuit board (not shown). Light-emitting element 15 emits light by applying a voltage to first mounting electrode 17A and second mounting electrode 17B. Radiated light LE, emitted from the surface (light output surface) of light-emitting element 15, passes through the transparent cover and is radiated to the outside.

[0079] Next, the joining of the substrate 11 and the flange 13B of the light-transmitting cover 13 will be described.

[0080] (Transparent cover 13 and flange 13B)

[0081] In addition, if Figure 1A 、 Figure 1B and Figure 1E As shown, light-transmitting cover 13 comprises a hemispherical dome portion 13A serving as a window, and a flange 13B extending from the bottom (end) of dome portion 13A. Flange 13B has a cylindrical outer shape. More specifically, the bottom surface of flange 13B has a circular ring shape (center: C) concentric with the center of dome portion 13A. In other words, the outer edge (outer periphery) of flange 13B is concentric with the inner edge (inner periphery) of flange 13B.

[0082] (Flange fixing layer 21)

[0083] Figure 2B This is a cross-sectional view schematically showing a state before bonding of substrate 11 and translucent cover 13. As described above, flange 13B includes ceramic layer 21C welded to bottom surface (flange bonding surface) 13S of flange 13B and metal layer 21M fixed to ceramic layer 21C.

[0084] The flange fixing layer 21 is bonded to the base metal layer 12 by the cover bonding layer 22 to form a bonding portion 24 (see Figure 2A ), thereby maintaining the airtightness between the substrate 11 and the transparent cover 13.

[0085] The bottom surface 13S of the flange 13B is a flat surface, but may be roughened or grooves may be formed on the flat surface to improve the adhesion of the ceramic layer 21C.

[0086] More specifically, white alumina or black alumina can be used for the ceramic layer 21C. An example of black alumina is black alumina (AR(B)) (manufactured by Asusac Corporation), which has a black hue and suppresses surface reflection while maintaining the strength and durability that are advantages of fine ceramics. (The reflectivity is 5.1% to 15.3% at a wavelength of 240 to 2600 nm.) White alumina is an aluminum oxide-based fine ceramic used in semiconductor and liquid crystal manufacturing equipment, and has a white or ivory hue.

[0087] Glass is primarily composed of silicon oxide (SiO2), so it exhibits strong adhesion to ceramics containing oxygen (O) elements such as zirconium oxide and magnesium oxide in addition to aluminum oxide, as well as ceramics containing silicon (Si) elements such as silicon carbide and silicon nitride. These ceramics can also be used as single or composite materials.

[0088] A ceramic having reflective properties that diffusely reflect light or absorptive properties that absorb light can be used for the ceramic layer 21C. On the other hand, metal will enter the concave and convex parts of the surface composed of fine grain boundaries of the ceramic as a polycrystalline body, so by sandwiching the ceramic layer 21C, it is possible to prevent the metal layer 21M from peeling off from the flange 13B. In addition, by selecting a metal that is easily oxidized, such as chromium (Cr), titanium (Ti), nickel (Ni), etc., for the metal oxide in contact with the ceramic layer 21C of the metal layer 21M, a part of the metal is bonded to the ceramic, thereby achieving a higher adhesion. Similarly, by selecting a metal that is easily nitrided, such as chromium (Cr), titanium (Ti), tungsten (W), etc., for the metal nitride in contact with the ceramic layer 21C of the metal layer 21M, a part of the metal is bonded to the ceramic, thereby achieving a higher adhesion.

[0089] The metal layer 21M can be, for example, a chromium / nickel / gold (Cr / Ni / Au) layer or a titanium / palladium / copper / nickel / gold (Ti / Pd / Cu / Ni / Au) layer (the Au layer is the outermost layer).

[0090] The ceramic layer 21C can be formed, for example, by injecting ceramic powder into a high-temperature, high-speed plasma jet and spraying the resulting molten particles onto the glass (plasma spraying). Alternatively, the metal layer 21M can be formed by employing the same plasma spraying method, electron beam evaporation, or the like.

[0091] (Substrate Metal Layer 12)

[0092] like Figure 1A and Figure 1D As shown, a metal ring body having a circular ring shape, namely the substrate metal layer 12, is fixed to the substrate 11, and a substrate bonding surface 12S (the surface of the substrate metal layer 12) is formed. In more detail, the bonding area of ​​the substrate 11 to which the substrate metal layer 12 is fixed is formed flat, and the substrate metal layer 12 has a shape (i.e., a circular ring shape) and size corresponding to the bottom surface 13S of the flange 13B. Alternatively, the substrate metal layer 12 has the size of the overall flange bonding layer 21 including the bottom surface 13S of the flange 13B. It should be noted that, as described above, a metal that is easily nitrided (easy to oxidize in the case of oxide ceramics) is selected for the metal of the substrate 11 that contacts the base ceramic. As a result, a higher bonding property can be obtained.

[0093] The substrate metal layer 12 has a structure in which tungsten, nickel, and gold are stacked in this order (W / Ni / Au), or a structure in which nickel-chromium alloy, gold, nickel, and gold are stacked in this order (NiCr / Au / Ni / Au) on the substrate 11 .

[0094] The base metal layer 12 is electrically insulated from the first wiring electrode 14A, the second wiring electrode 14B, the light emitting element 15 , and the protection element 16 , and is formed to surround the first wiring electrode 14A, the second wiring electrode 14B, the light emitting element 15 , and the protection element 16 .

[0095] A ring-shaped bonding material is placed on the ring-shaped base metal layer 12, and a force F is applied to the light-transmitting cover 13 to press it while heating it. Figure 2A As shown, a ring-shaped cover bonding layer 22 bonded to the light-transmitting cover 13 is formed on the substrate 11 .

[0096] The bonding material constituting the cover bonding layer 22 is, for example, a flux-free, annular AuSn (gold-tin) sheet made of an alloy material containing 20 wt% Sn (melting temperature: approximately 280°C). Alternatively, a layer of Au (10 to 30 nm) may be provided on both surfaces of the gold-tin alloy sheet. This prevents oxidation of the AuSn alloy and enables uniform melting in the cover bonding process described later, thereby improving airtightness. Furthermore, the Au layer dissolves into the cover bonding layer 22 during melt solidification (bonding).

[0097] [Method for Manufacturing Light-Emitting Device 10]

[0098] Hereinafter, a method for manufacturing the light emitting device 10 will be described in detail and specifically.

[0099] (Component bonding process)

[0100] First, a volatile solder paste is applied to the first wiring electrode 14A of the substrate 11 for component bonding. As the volatile solder paste, a volatile solder paste solder composed of a flux having a boiling point near the melting point and gold-tin alloy (Au-Sn) microparticles is used. The composition of the gold-tin alloy uses an alloy material of Au-Sn: 20wt% with a melting temperature of approximately 280°C. The particle size is several nanometers to tens of micrometers. The flux is, for example, rosin, alcohols, sugars, esters, fatty acids, oils, polymerized oils, surfactants, organic acids, etc., which are carbonized under the light (365nm) of the light-emitting element 15.

[0101] Next, light-emitting element 15 is placed on the volatile solder paste, and the substrate is heated to 300°C. The AuSn is then melted and solidified, bonding light-emitting element 15 to first wiring electrode 14A. This bonding is performed simultaneously when protective element 16 is mounted. At this point, the flux contained in the volatile solder paste is almost completely volatilized.

[0102] Next, the bonding pad 15B of the upper electrode of the light emitting element 15 and the second wiring electrode 14B are electrically connected by the bonding wire 18C (Au wire).

[0103] (Cover joining process)

[0104] After the excimer light cleaning step, the substrate 11 and the transparent cover 13 were placed on a cover bonding device. Then, the atmosphere of the substrate 11 and the transparent cover 13 was set to a vacuum state and subjected to a heating treatment (annealing treatment) at 275° C. for 15 minutes.

[0105] Next, the substrate 11 and the light-transmitting cover 13 are filled with dry nitrogen (N2) gas to form an atmosphere of 1 atmosphere (101.3 kPa). Figure 2B As shown, a ring-shaped AuSn sheet (bonding material of the cover bonding layer 22 ) is placed on the substrate metal layer 12 of the substrate 11 , and the light-transmitting cover 13 is further placed on the ring-shaped AuSn sheet and pressed.

[0106] While pressing the transparent cover 13 against the ring-shaped AuSn sheet, the AuSn sheet is heated to 300°C. The AuSn sheet melts due to the heat, melting a small amount of the gold in the metal layer 12 and the metal layer 21M. The AuSn sheet then solidifies upon cooling. As described above, the substrate 11 and the transparent cover 13 are bonded together, completing the fabrication of the semiconductor light-emitting device 10.

[0107] [Ceramic layer 21C of flange 13B]

[0108] Figure 3A This is a partially enlarged cross-sectional view showing a portion of the flange 13B and the flange fixing layer 21 when a light-reflecting ceramic (white alumina) is used as the ceramic layer 21C. The ceramic layer 21C in this case is denoted as ceramic layer 21C(W).

[0109] in addition, Figure 3B This is a partially enlarged cross-sectional view showing a portion of the flange 13B and the flange fixing layer 21 when a light-absorbing ceramic (black alumina) is used as the ceramic layer 21C. The ceramic layer 21C in this case is denoted as ceramic layer 21C(B).

[0110] In this specification, unless otherwise specified, the light-reflective ceramic layer 21C(W) and the light-absorbing ceramic layer 21C(B) are both referred to as the ceramic layer 21C.

[0111] It should be noted that the flange 13B is bonded to the substrate 11 (substrate metal layer 12 ) by the cover bonding layer 22 , but illustration of this portion is omitted.

[0112] Reference Figure 3A To illustrate, light La incident on flange 13B from light-emitting element 15 is reflected by flange 13B and emitted primarily toward the sides of light-emitting device 10. Furthermore, light Lb guided from dome portion 13A, which serves as a window, to flange 13B is diffusely reflected by ceramic layer 21C (W) and emitted primarily toward the front of light-emitting device 10.

[0113] Therefore, by using the light-reflecting ceramic layer 21C(W), it is possible to increase the light output of the light-emitting device 10. For example, the emitted light can be efficiently utilized in a device including a reflector covering the outer periphery of the light-emitting device 10.

[0114] Reference Figure 3B In this description, light La incident on flange 13B from light emitting element 15 is reflected by flange 13B and radiated outside light emitting device 10. Light Lb guided from dome portion 13A serving as a window to flange 13B is absorbed by ceramic layer 21C(B).

[0115] Therefore, using the light-absorbing ceramic layer 21C(B) can suppress stray light that is mainly radiated toward the front of the light emitting device 10. For example, in a device having a condenser lens or the like in front of the light emitting device 10, the stray light can be prevented from entering.

[0116] It should be noted that, for example, when measuring with the upper surface of the substrate 11 as the height reference, the height FL of the upper surface (the surface facing the bottom surface) 13F of the flange 13B is higher than the height EL of the light emitting surface 15S of the light emitting element 15 (see Figure 2A ), light La incident on flange 13B from light emitting element 15 is generated. That is, by positioning upper surface 13F of flange 13B behind light emitting surface 15S of light emitting element 15 in the light emitting direction, light La incident on flange 13B from light emitting element 15 can be attenuated (or eliminated).

[0117] As described above, in the light-emitting device 10 of this embodiment, the flange-bonding layer 21, comprised of the ceramic layer 21C and the metal layer 21M, is bonded to the flange 13B of the light-transmitting cover 13. The metallized layer, through the ceramic layer, provides strong adhesion to glass such as quartz glass, thereby preventing the metallized layer from peeling off the glass. Consequently, the bond strength between the light-transmitting cover 13 and the substrate 11 is strong, achieving a sealed structure with excellent airtightness.

[0118] [Second embodiment]

[0119] Figure 4A It is a cross-sectional view schematically showing a cross section of a semiconductor light emitting device 30 according to the second embodiment of the present invention. Figure 4B It is an enlarged representation Figure 4A A partially enlarged cross-sectional view of the joining portion (W portion).

[0120] The semiconductor light emitting device 30 of the present embodiment differs from the semiconductor light emitting device 10 of the first embodiment described above in that a ceramic layer 21C is formed to extend from the bottom surface 13S of the flange 13B to the inner side surface of the translucent cover 13 .

[0121] In more detail, Figure 4A and Figure 4B As shown, ceramic layer 21C is formed to extend from bottom surface 13S of flange 13B to the inner side surface of translucent cover 13 and to cover the entire inner circumference of flange 13B. In this embodiment, a recess is provided in the inner circumference of flange 13B, and ceramic is welded to the recess.

[0122] Specifically, ceramic layer 21C is composed of a portion where ceramic is fused to the bottom surface of flange 13B and a portion where ceramic is fused to the recess (ceramic layer inner peripheral portion 21P). Ceramic layer 21C has an L-shaped cross section perpendicular to substrate 11 .

[0123] The inner peripheral portion 21P of the ceramic layer has a height HC (the height from the bottom surface of the ceramic layer 21C) in a cross section perpendicular to the substrate 11. Furthermore, for example, when the upper surface of the substrate 11 is used as a reference plane, the height (horizontal height) CL of the top surface of the inner peripheral portion 21P of the ceramic layer is higher than the height (horizontal height) EL of the light emitting surface 15S of the light emitting element 15 relative to the upper surface of the substrate 11. It should be noted that while the description herein uses the upper surface of the substrate 11 as the height reference, the height can also be measured in the light emitting direction of the light emitting element 15 (a direction perpendicular to the light emitting surface 15S) using a plane parallel to the light emitting surface 15S of the light emitting element 15 as the reference plane.

[0124] Next, refer to Figure 5A 、 Figure 5B and Figure 5C , which describes the reflection and absorption of the incident light when the light emitted from the light emitting element 15 enters the flange 13B.

[0125] Figure 5A In the case where the ceramic layer 21C is a light-reflecting ceramic layer 21C (W), Figure 5B This is a partially enlarged cross-sectional view showing a case where the ceramic layer 21C is a light-absorbing ceramic layer 21C (B). Figure 5C It is a partially enlarged cross-sectional view showing a case where the ceramic layer 21C is composed of a light-absorbing ceramic layer 21C(B) and a light-reflecting ceramic layer 21C(W) (two-layer structure), wherein the ceramic layer 21C(B) is welded to the flange 13B; and the ceramic layer 21C(W) is formed on the ceramic layer 21C(B).

[0126] Reference Figure 5A To illustrate, light La incident on flange 13B from light-emitting element 15 is diffusely reflected by inner circumference 21P of reflective ceramic layer 21C(W), thereby shielding it. The reflected light is then converted into light emitted by the light-emitting device. Furthermore, light Lb guided from dome portion 13A, serving as a window, to flange 13B is diffusely reflected by ceramic layer 21C(W) and radiated primarily toward the front of light-emitting device 10.

[0127] Therefore, it is possible to improve light output while suppressing light emitted from the outer side surface of the flange portion 13B of the light emitting device 10 .

[0128] In addition, refer to Figure 5B To explain, the light La incident on the flange 13B from the light emitting element 15 and the light Lb guided from the dome portion 13A to the flange 13B are absorbed by the ceramic layer 21C (B).

[0129] Therefore, it is possible to prevent light that cannot be visually recognized, such as ultraviolet light and infrared light, from being output from the peripheral portion of the light emitting device 10 .

[0130] In addition, refer to Figure 5C To illustrate, light La incident on flange 13B from light-emitting element 15 is diffusely reflected by ceramic layer 21C(W), thereby shielding it. The reflected light is then converted into light emitted by the light-emitting device. Light Lb guided through flange 13B is absorbed by ceramic layer 21C(B), preventing this light Lb from being emitted from light-emitting device 10.

[0131] Therefore, it is possible to improve light output while suppressing light that cannot be visually recognized, such as ultraviolet light and infrared light, from being output from the peripheral portion of the light emitting device 10 .

[0132] It should be noted that, from the perspective of shielding the light emitted from the side of the light-emitting element 15 (the side of the flange 13B), it is preferred that the height CL of the inner peripheral portion 21P of the ceramic layer is the same as the height of the upper surface 13F of the flange 13B; or Figure 6 As shown, the top surface of the inner peripheral portion 21P reaches inside the dome portion 13A and the inner peripheral portion 21P (top surface height CL) has a height exceeding the upper surface 13F (height FL) of the flange 13B (CL>FL).

[0133] Furthermore, as described in the first embodiment, for example, when the height is measured with the upper surface of the substrate 11 as a height reference, the height FL of the upper surface (the surface facing the bottom surface) 13F of the flange 13B is higher than the height EL of the light emitting surface 15S of the light emitting element 15 (see FIG. Figure 2A ), light La incident on flange 13B from light emitting element 15 is generated. That is, by positioning upper surface 13F of flange 13B behind light emitting surface 15S of light emitting element 15 in the light emitting direction, light La incident on flange 13B from light emitting element 15 can be attenuated (or eliminated).

[0134] [Modification]

[0135] Figure 7 This is a partially enlarged cross-sectional view schematically showing an enlarged cross section of a portion of the flange 13B and the flange fixing layer 21 in a modified example of the second embodiment.

[0136] In this variation, a light-shielding layer 27 made of ceramic is provided on at least the upper surface of flange 13B. Flange 13B can shield light emitted in front of semiconductor light-emitting device 30 by light-shielding layer 27. Light-shielding layer 27 can be formed of a light-absorbing ceramic, such as black alumina, as appropriate.

[0137] As described above, ceramics have strong adhesion strength to glass and high weather resistance, and therefore do not deteriorate even when provided on the surfaces of the dome portion 13A and the flange portion 13B, thereby achieving a semiconductor light emitting device 30 with a long service life.

[0138] It should be noted that, in the second embodiment described above, a recess is provided on the inner periphery of flange 13B and ceramic is welded to the recess. However, the present invention is not limited to this. For example, instead of providing the recess on light-transmitting cover 13, a ceramic layer may be welded to the inner side surface of flange 13B in the first embodiment.

[0139] As described above, in the light-emitting device 30 of this embodiment, the ceramic layer is not only bonded to the bottom surface of flange 13B but also to the entire inner circumference of flange 13B. This further enhances the bond strength with the quartz glass, preventing delamination from the glass. Consequently, the bond strength between the light-transmitting cover 13 and the substrate 11 is strong, achieving an airtight seal.

[0140] As described above in detail, the semiconductor light-emitting device of this embodiment can provide a semiconductor device having high reliability and high environmental resistance such as high moisture resistance and high corrosion resistance, which can maintain high airtightness even under long-term use.

Claims

1. A semiconductor light emitting device, characterized in that: have: Semiconductor light emitting element; a substrate on which the semiconductor light emitting element is mounted and which has a substrate bonding surface, to which a ring-shaped substrate metal layer is fixed; and a light-transmitting cover made of glass and having a window portion and a flange, wherein the window portion allows light emitted by the semiconductor light-emitting element to pass through; the flange having an annular flange fixing layer fixed to its bottom surface, the flange fixing layer having a size corresponding to the substrate metal layer; the flange fixing layer is bonded to the substrate metal layer to form a space for accommodating the semiconductor light-emitting element; and the light-transmitting cover is sealed to the substrate; The flange fixing layer is composed of a ceramic layer welded to the flange and a metal layer formed on the ceramic layer.

2. The semiconductor light emitting device according to claim 1, wherein The ceramic layer has an inner peripheral portion extending from the bottom surface of the flange to the inner side surface of the light-transmitting cover and fixed to the inner peripheral surface of the flange in a manner extending over the entire circumference thereof.

3. The semiconductor light emitting device according to claim 2, wherein: The flange has a recessed portion on its inner peripheral portion, and the inner peripheral portion of the ceramic layer is formed so that ceramic is fused to the recessed portion.

4. The semiconductor light emitting device according to claim 2, wherein: The upper surface of the flange is located rearward of the light emitting surface of the semiconductor light emitting element in the light emitting direction of the semiconductor light emitting element.

5. The semiconductor light emitting device according to claim 2, wherein: When measured along the light emitting direction of the semiconductor light emitting element, the height of the top surface of the inner peripheral portion of the ceramic layer is higher than the height of the light emitting surface of the semiconductor light emitting element. The semiconductor light emitting device according to claim 1 , wherein: The ceramic layer is a black aluminum oxide layer.

7. The semiconductor light emitting device according to claim 1, wherein The ceramic layer is composed of a black aluminum oxide layer welded to the flange and a white aluminum oxide layer welded to the black aluminum oxide layer.

8. The semiconductor light emitting device according to claim 1, wherein The ceramic layer is made of at least one material selected from the group consisting of aluminum oxide, silicon carbide, silicon nitride, aluminum nitride, and zirconium oxide.

9. The semiconductor light emitting device according to claim 3, wherein: When measured along the light emitting direction of the semiconductor light emitting element, the height of the top surface of the inner peripheral portion of the ceramic layer is higher than the height of the light emitting surface of the semiconductor light emitting element.

10. The semiconductor light emitting device according to claim 2, wherein: The ceramic layer is a black aluminum oxide layer.

11. The semiconductor light emitting device according to claim 5, wherein: The ceramic layer is a black aluminum oxide layer.

12. The semiconductor light emitting device according to claim 2, wherein: The ceramic layer is composed of a black aluminum oxide layer welded to the flange and a white aluminum oxide layer welded to the black aluminum oxide layer.

13. The semiconductor light emitting device according to claim 5, wherein: The ceramic layer is composed of a black aluminum oxide layer welded to the flange and a white aluminum oxide layer welded to the black aluminum oxide layer.

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