Light emitting device and method of manufacturing the same

Abstract

Provided is a manufacturing method of a light-emitting device having high light output and high reliability. The manufacturing method includes: a step of applying a solution obtained by dissolving a fluororesin into an amorphous fluororesin with a solvent to an upper surface of a device substrate and a surface of a light-emitting element, and allowing the solvent to evaporate to form a film-like first sealing member of the amorphous fluororesin; a temporary fixing step of pressing an amorphous fluororesin pellet against the softened first sealing member on the upper surface of the light-emitting element to perform joining; and a step of softening and flowing the amorphous fluororesin pellet to form a second sealing member joined to the first sealing member.

Description

Technical Field

[0001] This invention relates to a light-emitting device including a semiconductor light-emitting element and a method for manufacturing the same. Background Technology

[0002] Patent Document 1 discloses an ultraviolet light-emitting device and its manufacturing method. The method involves injecting a coating solution obtained by dissolving amorphous fluororesin into a recess in a sub-mount. The coating solution is then heated and dried to form a resin film. This resin film covers the sidewall surfaces and inner surface of the bottom surface of the sub-mount, as well as the upper and side surfaces of the ultraviolet light-emitting element on the bottom surface of the sub-mount (a flip-chip mounted on the bottom surface). Subsequently, solid amorphous fluororesin is placed in the space of the recess in the sub-mount covered with the resin film, and the amorphous fluororesin is heated to melt it, thereby molding the resin film to fill the recess. In the structure of the ultraviolet light-emitting device, a focusing lens is fixed to the upper surface of the resin film filling the recess with an adhesive.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: WO 2014 / 178288 Summary of the Invention

[0006] The problem to be solved by the present invention

[0007] The problem with the ultraviolet light-emitting device described above is that when using amorphous fluororesin with non-reactive terminal functional groups that cannot bond with metals, the resin film on the upper or side surface of the ultraviolet light-emitting element peels off, thereby reducing the optical output of the ultraviolet light-emitting device. Furthermore, in the manufacturing process of the aforementioned ultraviolet light-emitting device, the step of filling the space of the recess in the sub-base with sidewall portions with amorphous fluororesin complicates the structure and manufacturing method of the ultraviolet light-emitting device.

[0008] The present invention was made in view of the above-mentioned problems, and the object of the present invention is to provide a highly reliable ultraviolet light emitting device with high optical output or a method for manufacturing the ultraviolet light emitting device.

[0009] Solution to the problem

[0010] To achieve the above objectives, a method for manufacturing a light-emitting device is provided. The light-emitting device includes a device substrate, a light-emitting element, and a sealing member of an amorphous fluoropolymer. The device substrate includes a plurality of bonding pads and an annular member spaced apart from the plurality of bonding pads and encompassing the plurality of bonding pads on a flat substrate. The light-emitting element is flip-chip bonded to the plurality of bonding pads on the device substrate and emits ultraviolet light. The sealing member allows light emitted from the light-emitting element to pass through and cover the upper surface of the light-emitting element and the device substrate. The manufacturing method includes: applying a solution obtained by dissolving a fluoropolymer (which will become an amorphous fluoropolymer) in a solvent to the upper surface of the device substrate and the surface of the light-emitting element, and evaporating the solvent to form a thin film of amorphous fluoropolymer as a first sealing member; a temporary fixing step of pressing amorphous fluoropolymer granules onto the softened first sealing member on the upper surface of the light-emitting element for bonding; and a step of softening and flowing the amorphous fluoropolymer granules to form a second sealing member bonded to the first sealing member.

[0011] The light-emitting device includes a device substrate, a light-emitting element, and a sealing member of amorphous fluoropolymer. The device substrate includes a plurality of bonding pads and an annular member spaced apart from the bonding pads and encompassing the bonding pads on a flat substrate. The light-emitting element is flip-chip bonded to the plurality of bonding pads on the device substrate and emits ultraviolet light. The sealing member allows light emitted from the light-emitting element to pass through and cover the upper surface of the light-emitting element and the device substrate. The device substrate includes a substrate of AlN ceramic that is resistant to ultraviolet light. In the light-emitting element, a portion of the surface in contact with the amorphous fluoropolymer is an N-atom surface on which AlN single crystals are polarized to δ-particles. - The sealing member includes: a first sealing member in the form of a thin film of amorphous fluororesin, which adheres tightly to and covers the surface of the light-emitting element and the upper surface of the device substrate; and a second sealing member in the form of a convex shape of amorphous fluororesin, which adheres tightly to and covers the first sealing member.

[0012] The effects of the invention

[0013] The present invention provides a highly reliable ultraviolet light emitting device with high optical output or a method for manufacturing the ultraviolet light emitting device. Attached Figure Description

[0014] Figure 1 This is a schematic top view of the light-emitting device according to an embodiment of the present invention; Figure 2 The light-emitting device is along Figure 1 A schematic cross-sectional view of line AA; Figure 3It is the molecular formula of the perfluoropolymer resin representing the sealing material of the light-emitting device in this embodiment; Figure 4 It is the molecular formula of the perfluoropolymer resin representing the sealing material of the light-emitting device in this embodiment; Figure 5 The molecular formula of another perfluoropolymer resin used as the sealing material for the light-emitting device in this embodiment; Figure 6 This is a schematic cross-sectional view of the device substrate of the light-emitting device according to this embodiment; Figure 7 This is a schematic cross-sectional view illustrating a portion of the manufacturing process of a light-emitting device according to an embodiment of the present invention; Figure 8 This is a schematic cross-sectional view illustrating a portion of the manufacturing process of a light-emitting device according to an embodiment of the present invention; Figure 9 This is a schematic cross-sectional view illustrating a portion of the manufacturing process of a light-emitting device according to an embodiment of the present invention; Figure 10 This is a schematic cross-sectional view illustrating a portion of the manufacturing process of a light-emitting device according to an embodiment of the present invention; Figure 11 This is a schematic cross-sectional view illustrating a portion of the manufacturing process of a light-emitting device according to an embodiment of the present invention; Figure 12 This is a schematic cross-sectional view illustrating a portion of the manufacturing process of a light-emitting device according to an embodiment of the present invention; Figure 13 This is a schematic cross-sectional view illustrating a portion of the manufacturing process of a light-emitting device according to an embodiment of the present invention; Figure 14 This is a schematic cross-sectional view illustrating a portion of the manufacturing process of a light-emitting device according to embodiments of the present invention; and Figure 15 This is a table showing the results of verification tests on the resin granule heating bonding step in the manufacturing method of the light-emitting device according to embodiments of the present invention. Detailed Implementation

[0015] Embodiments of the light-emitting device and its manufacturing method according to the present invention are described below. In the following description and drawings, the same reference numerals are given to substantially the same or equivalent parts, and explanations of overlapping components are omitted. The figures are not necessarily drawn strictly to scale.

[0016] Figure 1 A schematic top view of the light-emitting device 10 according to an embodiment is shown. Figure 2 The light-emitting device 10 is schematically shown along... Figure 1The cross section of line AA. In this specification, Figure 2 The surface facing upwards is defined as the upper surface, and Figure 2 The surface facing downwards is defined as the lower surface.

[0017] like Figure 1 and Figure 2 As shown, the light-emitting device 10 includes a device substrate 11 having a rectangular plate shape in the plan view, a rectangular light-emitting element 15 placed on the upper surface of the device substrate 11, and a sealing member 13 (in other words, sealing resin 13) of amorphous fluoropolymer covering the upper surfaces of the device substrate 11 and the light-emitting element 15.

[0018] The sealing member 13 includes a first sealing member 13A covering the upper surface of the device substrate 11 and the surface of the light-emitting element 15, and a protruding second sealing member 13B covering the first sealing member 13A. In this embodiment, the light-emitting element 15 is a semiconductor light-emitting element that emits ultraviolet light, and the sealing member 13 is a thermoplastic amorphous fluoropolymer that allows ultraviolet light emitted from the light-emitting element 15 to pass through. In other words, the light-emitting device 10 is a semiconductor light-emitting device that emits ultraviolet light.

[0019] (Device board)

[0020] The device substrate 11 is a double-sided wiring board, wherein wiring patterns for supplying power to the light-emitting element 15 are provided on both surfaces of a flat insulating substrate having a rectangular upper surface. For the substrate of the device substrate 11, aluminum nitride (AlN) ceramic has excellent thermal radiation properties and a thermal conductivity of 150 to 220 (W / mK). For the substrate of the device substrate 11, ultraviolet-resistant ceramics, such as alumina (Al2O3) and silicon nitride (Si3N4), can be used.

[0021] A first bonding pad 14A and a second bonding pad 14B for bonding the light-emitting element 15 are provided on the upper surface of the device substrate 11. The planar shapes of the first bonding pad 14A and the second bonding pad 14B are approximately the same as the planar shapes of the corresponding first element electrode 15A and the second element electrode 15B of the light-emitting element 15, respectively. A first mounting electrode 17A and a second mounting electrode 17B for mounting the light-emitting device 10 to a circuit board are provided on the lower surface (back side) of the device substrate 11. The first bonding pad 14A is electrically connected to the first mounting electrode 17A through a first metal via 18A penetrating the device substrate 11 in the vertical direction. The second bonding pad 14B is electrically connected to the second mounting electrode 17B through a second metal via 18B penetrating the device substrate 11 in the vertical direction.

[0022] In the following text, when the first bonding pad 14A and the second bonding pad 14B are indistinguishable from each other, they are described as bonding pads (14A, 14B). When the first component electrode 15A and the second component electrode 15B are indistinguishable from each other, they are described as component electrodes (15A, 15B). When the first mounting electrode 17A and the second mounting electrode 17B are indistinguishable from each other, they are described as mounting electrodes (17A, 17B). When the first metal via 18A and the second metal via 18B are indistinguishable from each other, they are described as metal vias (18A, 18B).

[0023] The bonding pads (14A, 14B) contain a copper (Cu) base material and are provided with protective layers of nickel (Ni) and gold (Au) sequentially laminated on the upper surface (surface) of the base material. The mounting electrodes (17A, 17B) contain a Cu base material and are provided with protective layers of Ni and Au sequentially laminated on the lower surface (surface) of the base material. The vias (18A, 18B) contain only a Cu base material. In some cases, the protective layer disposed on the surface of the base material is described below as Ni / Au.

[0024] For the base materials of the bonding pads (14A, 14B), mounting electrodes (17A, 17B), and metal vias (18A, 18B), metals such as aluminum (Al) and tungsten (W) can be selected. For the protective layer, metals such as titanium (Ti) / gold (Au) and chromium (Cr) / gold (Au) can also be selected.

[0025] On the upper surface of the device substrate 11, an annular member 12 is spaced apart from and surrounds the bonding pads (14A, 14B). The annular member 12 is a wide ring in top view and is configured to have concentric inner and outer circles. In other words, the annular member 12 is a ring with a uniform bandwidth. The inner circle of the annular member 12 is larger than the outline of the light-emitting element 15 and smaller than the inscribed circle of the device substrate 11. The annular member 12 comprises a Cu base material, and a Ni / Au protective layer is provided on the upper surface (surface) of the base material. The annular member 12 may contain only the base material without the protective layer. The annular member 12 may be connected to either the first mounting electrode 17A or the second mounting electrode 17B via a metal through-hole.

[0026] The annular member 12 may have the following shapes: an ellipse with a center of rotational symmetry, a petal shape with radially continuous arcs, or a polygon with four or more sides. The annular member 12 only needs to have an inner surface that defines the outer edge of the first sealing member 13A, and for example, the shape of the outer surface may be the same as the shape of the device substrate 11.

[0027] For the base material of the annular member 12, metals such as Al and W can also be selected. For the protective layer, metal layers such as Ti / Au and Cr / Au can also be selected. The annular member 12 can be the same ceramic as the substrate of the device substrate 11. For example, a silica-based inorganic adhesive containing alumina particles or zirconium oxide particles as aggregates can be used.

[0028] (Light-emitting element)

[0029] The light-emitting element 15 includes: an element substrate SUB, which has a rectangular shape and a flat shape in a plan view; and a light-emitting functional layer LEL, wherein an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer are sequentially stacked on a flat surface of the element substrate SUB. On the surface of the element substrate SUB opposite to the light-emitting functional layer LEL, a semiconductor light-emitting element (LED: light-emitting diode) including a first element electrode 15A and a second element electrode 15B is disposed. The first element electrode 15A is electrically connected to the p-type semiconductor layer, and the second element electrode 15B is electrically connected to the n-type semiconductor layer, and emits light from the surface of the element substrate SUB when a current is applied. In other words, the surface of the element substrate SUB without the light-emitting functional layer LEL is the light-emitting surface of the light-emitting element 15. In this embodiment, the element substrate SUB of the light-emitting element 15 is a single crystal of aluminum nitride (AlN), and the light-emitting functional layer LEL is a semiconductor crystal layer based on aluminum gallium nitride (AlGaN) crystal, which emits light with a wavelength of 265 nm.

[0030] The substrate SUB is an AlN single crystal with a wurtzite structure. The surface of the substrate SUB containing the light-emitting layer (LEL) is a +c plane (metallic surface) composed of aluminum (Al) atoms arranged on the surface. Conversely, the surface on the opposite side of the LEL is a -c plane (non-metallic surface) composed of nitrogen (N) atoms arranged on the surface. The Al atoms along the +c axis are polarized to δ... + Furthermore, the N atoms along the -c axis are polarized to δ. - In other words, the light-emitting surface of the light-emitting element 15 is composed of elements with polarization δ. - The -c plane (non-metallic surface) of the N atom is a crystal plane (N atom surface) on which the dangling bond of the N atom is exposed. The side surfaces of the light-emitting element 15 (especially the element substrate SUB) are a plane and m plane with dangling bonds of Al and N atoms, or higher-order crystal planes.

[0031] The AlGaN-based semiconductor crystal layer of the light-emitting layer (LEL) can be tuned to emit ultraviolet light with an emission wavelength of 200 nm to 300 nm. The p-type semiconductor layer, the light-emitting layer, and the n-type semiconductor layer of the LEL can each include a superlattice layer, a quantum well layer, a barrier layer, etc. It is not necessary for each layer to contain impurities.

[0032] In the light-emitting element 15, the first element electrode 15A and the second element electrode 15B are respectively bonded to the first bonding region 14A and the second bonding region 14B of the device substrate 11 via an Au-Sn based bonding member 15C. In other words, the light-emitting element 15 is flip-chip bonded to the device substrate 11 without wiring connections. In this embodiment, the light-emitting element 15 is positioned such that the center of the light-emitting element 15 (the intersection of the diagonals of the upper surface of the light-emitting element 15) aligns with the center of the annular member 12.

[0033] (Sealing component)

[0034] The sealing member 13 is a member that seals and protects the light-emitting element 15 while allowing light emitted from the light-emitting element 15 to pass through and guide it to the outside of the light-emitting device 10. The sealing member 13 includes a thin film-shaped first sealing member 13A covering the upper surface of the device substrate 11 and the surfaces of the light-emitting element 15 (side surfaces, upper surfaces, and lower surfaces excluding element electrodes (15A, 15B)), and a convex second sealing member 13B covering the first sealing member 13A.

[0035] like Figure 2 As shown, the first sealing member 13A adheres (bonds) to and covers the following surfaces: the upper surface of the substrate of the device substrate 11 within the inner surface of the annular member 12, including the bonding pads (14A, 14B) of the device substrate 11 and the side surfaces of the bonding structures of the light-emitting element 15 (element electrodes (15A, 15B)) and the bonding member 15C; and the lower, side, and upper surfaces of the light-emitting element 15, excluding the element electrodes (15A, 15B). The first sealing member 13A serves as an auxiliary adhesion layer for bonding the second sealing member 13B. The first sealing member 13A may fill the area surrounded by the upper surface of the device substrate 11, the side surfaces of the bonding structures, and the lower surface of the light-emitting element 15. The film thickness of the first sealing member 13A may be non-uniform. For example, the corner portion between the side surface of the light-emitting element 15 and the device substrate 11 may be thicker. The first sealing member 13A as described above can be formed by a solvent drying method (first sealing step) described later.

[0036] The second sealing member 13B is adhered (bonded) to the upper surface of the first sealing member 13A as an auxiliary adhesive layer and covers it, and is formed in a convex shape. In this embodiment, the second sealing member 13B is an ellipsoid obtained by rotating a semi-ellipse having a major axis in the vertical direction. The second sealing member 13B has a circular shape defined by the inner surface of the annular member 12 on the upper surface of the device substrate 11. In other words, the second sealing member 13B has a convex lens shape, and the major axis of the ellipsoid of the second sealing member 13B serves as the optical axis of the convex lens. In this embodiment, the center of the light-emitting element 15 overlaps with the center of the annular member 12. Therefore, the light emitted from the light-emitting element 15 has a directional characteristic of focusing along the optical axis of the lens. For the directional characteristic, by forming the second sealing member 13B as a hemisphere, the half-value angle of the semi-elliptical sphere having a minor axis in the vertical direction can be increased. The second sealing member 13B as described above can be formed by the granule softening and flow method (second sealing step) described later.

[0037] The first sealing member 13A and the second sealing member 13B are thermoplastic amorphous fluoropolymers (thermoplastic resins) that allow light emitted from the light-emitting element 15 to pass through. In this embodiment, as... Figure 3 As shown, a fluoropolymer resin with a backbone obtained by cyclopolymerization of perfluoro(4-vinyloxy-1-butene) (hereinafter also referred to as BVE) is used. The terminal functional group is a trifluoromethyl group (-CF3) with high light resistance to the emission wavelength of 265 nm of the light-emitting element 15. The fluoropolymer resin has a refractive index of 1.34 and a transmittance of more than 90% (thickness 200 μm). Compared with the light output of a light-emitting device sealed with a glass cover, the light output of the light-emitting device 10 using amorphous fluoropolymer resin as the sealing element 13 is increased by more than 1.5 times.

[0038] Similar backbones of fluoropolymers include, for example... Figure 4 The perfluoro(allyl vinyl ether) cyclic polymers shown, such as Figure 5 The examples shown are copolymers of perfluoro(2,2-dimethyl-1,3-dioxane) and tetrafluoroethylene. Examples of terminal functional groups include -COOH, -CONH-Si(OR)n (R: alkyl, n is an integer), etc. These terminal functional groups improve adhesion to another substance. Conversely, they exhibit lower lightfastness to ultraviolet light with wavelengths from 200 nm to 300 nm.

[0039] Amorphous fluororesins with the terminal functional group -CF3 have the following characteristics: high light resistance to 265 nm ultraviolet light, but extremely low adhesion (chemical bonding) to other substances. Therefore, in the light-emitting device 10 of this embodiment, a single-crystal AlN substrate with a wurtzite structure is used as the element substrate SUB of the light-emitting element 15, and as a polycrystalline AlN ceramic substrate is used as the base material of the element substrate 11, thereby improving the adhesion (chemical bonding) with the amorphous fluororesin with the terminal functional group -CF3.

[0040] Specifically, when the element substrate SUB of the light-emitting element 15 has a light-emitting surface (upper surface), the adhesion (chemical bonding) with the amorphous fluororesin obtained by cyclic polymerization of BVE having a terminal functional group -CF3 is improved. The light-emitting surface (upper surface) is composed of elements arranged thereon that are polarized to δ. - The dangling bonds of N atoms are present on the -c surface (non-metallic surface). Furthermore, since the dangling bonds of N atoms also exist on the side surfaces (e.g., a-surface, m-surface) of the element substrate SUB, adhesion (chemical bonding) with the amorphous fluororesin obtained through the cyclic polymerization of BVE with terminal functional groups -CF3 is improved. Similarly, since the dangling bonds of N atoms also exist on the AlN polycrystalline sintered ceramic, which serves as the substrate of the device substrate 11, adhesion (chemical bonding) with the amorphous fluororesin obtained through the cyclic polymerization of BVE with terminal functional groups -CF3 is improved. Additionally, the slight unevenness on the surface of the AlN polycrystalline sintered ceramic, which serves as the substrate of the device substrate 11, improves adhesion (physical bonding). Therefore, even when the first sealing member 13A is an amorphous fluororesin with terminal functional groups -CF3, adhesion to the light-emitting element 15 and the substrate of the device substrate 11 can be improved.

[0041] In this embodiment, the same amorphous fluororesin as the first sealing member 13A is used for the second sealing member 13B. Therefore, good adhesion exists between the first sealing member 13A and the second sealing resin 13B. Thus, the light-emitting device 10 can have a structure in which a convex lens-shaped seal 13 is disposed on the upper surface of a flat device substrate 11. In other words, a recess (frame) for holding the sealing member 13 (especially the second sealing member 13B) on the device substrate 11 is unnecessary, and the structure of the light-emitting device 10 can be simplified. Since the device substrate 11 does not have a recess (frame), the optical output of the light-emitting device 10 can be improved. Furthermore, since the sealing member 13 is formed of an amorphous fluororesin having the terminal functional group -CF3, it exhibits excellent light resistance (e.g., resistance to yellowing) to ultraviolet light (light emitted from the light-emitting element 15) with wavelengths of 200 nm to 300 nm. In other words, the present invention provides a highly reliable ultraviolet light-emitting device with high optical output.

[0042] While embodiments have been described above, the invention is not limited thereto. For example, by providing a slightly uneven structure on the surface of the light-emitting element 15, adhesion to the first sealing member 13A can be improved. For example, by arranging a plurality of (e.g., two, three, or four) light-emitting elements 15 in a manner that is centrally symmetrical about the annular member, the light output of the light-emitting device 10 can be improved.

[0043] (Manufacturing method)

[0044] Next, the manufacturing method of the light-emitting device 10 will be described. Figures 6 to 14 It is a diagram that schematically illustrates the various steps of the manufacturing process. Figure 15 It is a table used to determine when the second sealing member 13B engages with the upper surface of the first sealing member 13A.

[0045] The light-emitting device 10 is manufactured by a process including the following steps: an element bonding step of bonding the light-emitting element 15 to the device substrate 11, a first sealing step of forming a first sealing member 13A at the device substrate 11 where the light-emitting element 15 has been bonded, a temporary fixing step of temporarily fixing amorphous fluoropolymer granules as a second sealing member 13B, and a second sealing step of forming the second sealing member 13B at the device substrate 11 where the first sealing member 13A has been formed.

[0046] First, a square device substrate 11 is prepared, wherein a first bonding region 14A, a second bonding region 14B, and an annular member 12 with an inner diameter of 2.7 mm are formed on the upper surface (first surface) of an AlN ceramic substrate with sides of 3.6 mm and a thickness of 0.5 mm. Figure 6 The shapes of the first bonding pad 14A and the second bonding pad 14B are substantially the same as the shapes of the first element electrode 15A and the second element electrode 15B of the light-emitting element 15. Furthermore, as the light-emitting element 15, a light-emitting element having a long side of 0.95 mm, a short side of 0.75 mm, a thickness of 0.11 mm, and a peak wavelength of 265 nm is fabricated. Figure 7 The light-emitting element 15 includes a single-crystal AlN substrate SUB and an AlGaN-based light-emitting functional layer LEL disposed on the lower surface of the substrate SUB. A rectangular first element electrode 15A and a second element electrode 15B are disposed on the lower surface of the LEL. The upper surface of the substrate SUB is arranged with electrodes polarized to δ. - The -c facet of the N atom.

[0047] (Component bonding step: S10)

[0048] The component bonding step is a step in which the component electrodes (15A, 15B) of the light-emitting element 15 are bonded to the bonding pads (14A, 14B) of the device substrate 11 via bonding members 15C. First, solder paste containing 22% by weight of Au-Sn particles to be used as bonding members 15C is applied to the surface of the bonding pads (14A, 14B) of the device substrate 11. Figure 7 The application can be performed by methods such as screen printing, stamping, and potting. Next, the light-emitting element 15 is placed such that the element electrodes (15A, 15B) overlap with the corresponding bonding pads (14A, 14B) on which solder paste has been applied. Then, the 22% by weight Au-Sn particles contained in the solder paste are melted and solidified using a reflow oven heated to 300°C to bond the light-emitting element 15 to the device substrate 11. Figure 8 During reflow, components in the solder paste other than Au-Sn evaporate.

[0049] (First sealing step: S20)

[0050] The first sealing step is a step after the element bonding step (S10) whereby a first sealing member 13A is formed from a fluororesin solution AC on the surface of the light-emitting element 15 bonded to the device substrate 11 and on the upper surface of the device substrate 11 inside the annular member 12. The fluororesin solution AC is obtained by liquefying an amorphous fluororesin, which serves as the first sealing member 13A, with a solvent. To make the amorphous fluororesin the first sealing member 13A, a fluororesin obtained by cyclopolymerization of BVE having a terminal functional group -CF3 is used. A fluorinated organic solvent is used as the solvent.

[0051] First, a predetermined amount of fluororesin solution AC is dropped onto the upper surface of the light-emitting element 15. Figure 9 Next, the device substrate 11, on which the amorphous fluoropolymer solution AC has been dropped onto the upper surface of the light-emitting element 15, is placed on a hot plate, and the lower surface of the device substrate 11 is heated at 230°C for 60 minutes. During this period, the amorphous fluoropolymer solution AC diffuses and wets the area from the surface of the light-emitting element 15 (upper surface, side surface, and lower surface except for the element electrodes (15A, 15B)) to the upper surface of the substrate inside the annular member 12 of the device substrate 11, continuously covering this area. Simultaneously, the solvent of the amorphous fluoropolymer solution AC evaporates. Through this operation (solvent drying method), a first sealing member 13A, which is a thin film of amorphous fluoropolymer, is formed from the surface of the light-emitting element 15 to the upper surface of the substrate inside the annular member 12 of the device substrate 11. Figure 10 At this point, the amorphous fluoropolymer is chemically and physically bonded to the upper surface (c-plane of the AlN crystal) of the element substrate SUB, the side surface (m-plane and a-plane of the AlN crystal) of the light-emitting element 15, and the upper surface (AlN ceramic surface) of the substrate of the device substrate 11.

[0052] (Temporary fixation procedure: S30)

[0053] The temporary fixing step is a step after the first sealing step (S20) whereby the amorphous fluoropolymer granules 13BC, which serve as the second sealing member 13B, are temporarily fixed (bonded) to the upper surface of the light-emitting element 15 on the device substrate 11 using the first sealing member 13A as an auxiliary adhesion layer. The amorphous fluoropolymer granules 13BC are fluoropolymers obtained by cyclopolymerization of BVE having a terminal functional group -CF3. The amorphous fluoropolymer granules 13BC are quadrilateral prisms with a square top surface and a square bottom surface, each side being 1.8 mm long and 1.7 mm high.

[0054] First, the device substrate 11 after the first sealing step (S20) is placed on the sample stage HT of the temporary fixing device, and the lower surface of the device substrate 11 (the surface of the mounting electrodes (17A, 17B)) is heated at 120°C to 200°C in an air atmosphere to soften the first sealing member 13A. Figure 11 Next, using the adsorption clamp 28, the amorphous fluoropolymer granules 13BC are pressed onto the upper surface of the first sealing member 13A under a load of 10 gf to 100 gf for a period of 1 to 30 seconds. The amorphous fluoropolymer granules 13BC are pressurized and positioned such that the center of the bottom surface of the amorphous fluoropolymer granules 13BC aligns with the center of the light-emitting element 15. Figure 12 Through this action (heat-pressurized placement method), the amorphous fluoropolymer granules 13BC are bonded to the first sealing resin 13A. Since the element size of the light-emitting element 15 is 0.95 mm × 0.75 mm, the contact pressure between the amorphous fluoropolymer granules 13BC and the first sealing resin 13A during pressurized placement is 1.4 kgf / cm². 2 Up to 14 kgf / cm 2 Because the first sealing member 13A is properly bonded to the light-emitting element 15 in this embodiment, the first sealing member 13A will not peel off from the light-emitting element 15. In other words, because the first sealing member 13A is properly bonded to the light-emitting element 15, the amorphous fluoropolymer granules 13BC can be bonded (temporarily fixed) to the first sealing member 13A with high contact pressure. The amorphous fluoropolymer granules 13BC temporarily fixed as described above will not fall off during operations prior to the next step (e.g., cooling, transportation, and temporary storage). Details of the bonding conditions are described below.

[0055] (Second sealing step: 40)

[0056] The second sealing step is a step after the temporary fixing step (S30) to form a convex second sealing member 13B by softening and flowing the amorphous fluoropolymer granules 13BC at the device substrate 11 to cover the light-emitting element 15 and the upper surface of the device substrate 11.

[0057] First, the device substrate 11 after the temporary fixing step (S30) is placed in a decompression oven. Then, the pressure inside the oven is reduced to a few kPa, and the substrate is heated at 250°C for 4 hours to soften and flow the amorphous fluoropolymer granules 13BC. Figure 13 The amorphous fluoropolymer granules 13BC are molded into a predetermined shape. Through this operation (granule softening and flow method), a convex second sealing resin 13B is formed covering the first sealing member 13A. Figure 14 Through this operation, since the amorphous fluoropolymer granules 13BC are properly bonded to the first sealing member 13A, the amorphous fluoropolymer granules 13BC will not fall off or shift even after prolonged heating, and a second sealing member 13B of a predetermined shape can be formed.

[0058] Since the first sealing resin 13A, serving as an auxiliary adhesion layer, is formed on the surface of the light-emitting element 15 and the upper surface of the substrate reaches the annular member 12 of the device substrate 11, the resin obtained by softening and flowing the amorphous fluoropolymer granules 13BC can be easily spread and wetted there. Furthermore, during the process of softening and flowing the amorphous fluoropolymer granules 13BC to cover the first sealing member 13A, a weldable bonding surface is formed with the first sealing member 13A. In other words, the second sealing member 13B is appropriately bonded (attached) to the first sealing member 13A.

[0059] The shape of the amorphous fluoropolymer granules 13BC can be selected to correspond to the shape of the molded second sealing member 13B. For example, when the height of the quadrangular prism-shaped amorphous fluoropolymer granules 13BC is the same as one side of the bottom surface (cube), the second sealing member 13B has a hemispherical shape, and when the height is greater than one side of the bottom surface (cubic prism shape), the second sealing member 13B becomes an ellipsoid with its major axis as its optical axis.

[0060] The shape of the amorphous fluoropolymer granules 13BC is not limited to a square prism, but can also be a polygonal prism, such as a hexagonal prism, an octagonal prism, a cylinder, or a truncated pyramidal polygonal prism or cylinder. For example, when the amorphous fluoropolymer granules 13BC are formed into a truncated cylinder, the second sealing member 13B can be formed into a bullet shape after molding. When the second sealing member 13B is an inverted truncated cylinder, the second sealing member 13B can be formed into a sphere after molding.

[0061] (Evaluation of bonding conditions)

[0062] Next, the bonding conditions of the amorphous fluoropolymer granules 13BC in the temporary fixing step (S30) will be described. Figure 15 The table illustrates the bonding conditions. The horizontal items in the table are the lower surface temperature of the device substrate 11 (the surface temperature of the sample stage HT), while the vertical items are the loading time of the amorphous fluoropolymer granules 13BC. The contact pressure under load is 1.4 kgf / cm². 2 In the evaluation, a drop impact test was used to determine whether the result was good (OK: hold) or bad (NG: drop), in which the amorphous fluoropolymer granules 13BC were dropped 5 cm face down after temporary fixation.

[0063] Evaluation results: When the lower surface temperature of the device substrate 11 is 120°C, it performs well under a load of 4 seconds or more (OK: hold); when the lower surface temperature of the device substrate 11 is 130°C, it performs well under a load of 2 seconds or more; when the lower surface temperature of the device substrate 11 is 140°C, it performs well under a load of 2 seconds or more; when the lower surface temperature of the device substrate 11 is 150°C, it performs well under a load of 1 second or more; when the lower surface temperature of the device substrate 11 is 200°C, it performs well under a load of 1 second or more. Therefore, by further increasing the lower surface temperature of the device substrate 11, satisfactory temporary fixation can be achieved in a short time. From a manufacturing time perspective, the lower surface temperature of the device substrate 11 is preferably 150°C or higher. When the temperature of the lower surface of the device substrate 11 exceeds 200°C, the fluidity of the first sealing member 13A increases excessively, causing the amorphous fluoropolymer granules 13BC to slide laterally and cause positional displacement. Therefore, the temperature of the lower surface of the device substrate 11 is preferably below 200°C.

[0064] As described above, the manufacturing method including the first sealing step (S20), the temporary fixing step (S30), and the second sealing step (S40) allows for the formation of a sealing member 13 of amorphous fluoropolymer with extremely low adhesion in a protruding shape on the upper surface of the flat device substrate 11 without a frame. Even when the sealing member 13 is amorphous fluoropolymer, it can be suitably bonded to the surface of the light-emitting element 15 and the upper surface of the device substrate 11. In other words, a manufacturing method for a highly reliable ultraviolet light-emitting device with high light output can be provided.

[0065] Therefore, the present invention can provide a highly reliable ultraviolet light emitting device with high optical output or a method for manufacturing the ultraviolet light emitting device.

[0066] This invention is not limited to the embodiments described above. For example, the element substrate SUB of the light-emitting element 15 can be a boron nitride (BN) single crystal. Alternatively, it can be a gallium nitride (GaN) single crystal. However, when GaN is used as the element substrate, since the band gap of GaN is 3.4 eV, the wavelength of light emitted from the light-emitting functional layer LEL is limited to a wavelength greater than 365 nm.

[0067] The dimensions of the components mentioned above are merely examples.

[0068] The light-emitting device of the present invention can be used in various light sources. For example, the light-emitting device of the present invention can be used as a light source for resin curing devices; a light source for disinfection, sterilization and bacterial eradication devices; and a light source for sensors such as distance measuring devices.

[0069] Description of reference numerals in the attached figures

[0070] 10 Light-emitting devices

[0071] 11Device substrate

[0072] 12 ring components

[0073] 13 Sealing components

[0074] 13A First Sealing Component

[0075] 13B Second Sealing Component

[0076] 13BC amorphous fluoropolymer granules

[0077] 14A First Bonding Pad

[0078] 14B Second Bonding Pad

[0079] 15 light-emitting elements

[0080] 15A First Element Electrode

[0081] 15B Second Element Electrode

[0082] 15C joint components

[0083] 17A First Mounting Electrode

[0084] 17B Second Mounting Electrode

[0085] 18A First Metal Through Hole

[0086] 18B Second Metal Through Hole

[0087] LEL luminescent functional layer

[0088] SUB component substrate

Claims

1. A method for manufacturing a light-emitting device, wherein the light-emitting device includes a device substrate, a light-emitting element, and a sealing member of an amorphous fluoropolymer resin, the device substrate including a flat substrate, a plurality of bonding pads formed on the upper surface of the flat substrate, and an annular member formed to be spaced apart from and surrounding the plurality of bonding pads on the upper surface of the flat substrate, the light-emitting element being flip-chip bonded to the plurality of bonding pads of the device substrate and emitting ultraviolet light, and the sealing member allowing light emitted from the light-emitting element to pass through and cover the entire light-emitting element at the upper surface of the device substrate, and The manufacturing method includes: The step of applying a solution obtained by dissolving the fluororesin that will become the amorphous fluororesin in a solvent to the upper surface of the device substrate and the surface of the light-emitting element, and evaporating the solvent to form a thin film-shaped first sealing member of the amorphous fluororesin. A temporary fixing step of softening the first sealing member and pressing amorphous fluoropolymer granules onto the first sealing member formed on the upper surface of the light-emitting element to bond the amorphous fluoropolymer granules to the first sealing member. as well as The step of softening and flowing the amorphous fluoropolymer granules to form a second sealing member bonded to the first sealing member.

2. The method for manufacturing a light-emitting device as claimed in claim 1, wherein the amorphous fluororesin of the first sealing member and the second sealing member is a thermoplastic resin.

3. The method for manufacturing a light-emitting device as claimed in claim 2, wherein the amorphous fluororesin of the first sealing member and the second sealing member has a terminal functional group containing -CF3.

4. The method for manufacturing a light-emitting device as claimed in claim 2, wherein the amorphous fluororesin of the first sealing member and the second sealing member is a fluororesin obtained by cyclopolymerization of perfluorinated (4-vinyloxy-1-butene).

5. The method for manufacturing a light-emitting device as claimed in claim 1, wherein the light-emitting element has an emission wavelength of 200 nm to 300 nm.

6. The method of manufacturing a light-emitting device as claimed in claim 5, wherein the light-emitting element comprises an element substrate of AlN single crystal in the form of wurtzite, and at least one of the surfaces of the first sealing member bonded to the element substrate is a -c surface.

7. A light-emitting device, comprising: The device substrate includes a flat substrate, a plurality of bonding pads formed on the upper surface of the flat substrate, and an annular member formed to be spaced apart from and surrounding the plurality of bonding pads on the upper surface of the flat substrate. A light-emitting element, which is flip-chip bonded to the plurality of bonding pads on the device substrate and emits ultraviolet light; as well as An amorphous fluoropolymer sealing member that allows light emitted from the light-emitting element to pass through and cover the entire light-emitting element at the upper surface of the device substrate. The device substrate includes the substrate, which is an AlN ceramic that is resistant to ultraviolet light. In the light-emitting element, a part of a surface in contact with the amorphous fluorine resin is an N atom surface, and an AlN single crystal is polarized to δ - and The sealing member includes: a thin film-shaped first sealing member of the amorphous fluororesin, which tightly adheres to and covers the surface of the light-emitting element and the upper surface of the device substrate inside the annular member; The convex second sealing member of the amorphous fluororesin adheres tightly to and covers the first sealing member.

8. The light-emitting device of claim 7, wherein the amorphous fluororesin of the first sealing member and the second sealing member is a thermoplastic resin.

9. The light-emitting device of claim 8, wherein the amorphous fluororesin of the first sealing member and the second sealing member has a terminal functional group comprising -CF3.

10. The light-emitting device of claim 9, wherein the amorphous fluororesin of the first sealing member and the second sealing member is a fluororesin obtained by cyclopolymerization of perfluorinated (4-vinyloxy-1-butene).

11. The light-emitting device of claim 7, wherein the light-emitting element has an emission wavelength of 200 nm to 300 nm.

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