JP6800702B2 - Semiconductor light emitting device and its manufacturing method - Google Patents

Description

The present invention relates to a semiconductor light emitting device that converts light from a light emitting element into light having a desired wavelength by a wavelength conversion member and irradiates the light.

A semiconductor light emitting device is known that emits white light by converting the wavelength of light emitted from a semiconductor light emitting element by a wavelength conversion member. Such a semiconductor light emitting device is used as a light source for lighting equipment such as general lighting, street lights, and vehicle lighting equipment. In particular, vehicle lighting equipment and the like are required to have high front brightness, and therefore various semiconductor light emitting devices. Has been proposed.

For example, Patent Document 1 describes a light emitting element, a light transmitting member having a light emitting surface exposed to the outside and a side surface continuous from the light emitting surface and capable of wavelength conversion of light from the light emitting element, and a side surface of the light transmitting member. The front brightness is improved by providing a coating member containing a light-reflecting material that surrounds the side surface of the light emitting element and substantially only the light emitting surface on the upper surface as a light emitting region in the light emitting device. The light emitting device is disclosed.

Japanese Patent No. 552682

By the way, since the light transmitting member applied to the semiconductor light emitting device and the like disclosed in Patent Document 1 described above is made of an inorganic material having a flat light emitting surface surface, the light emitted from the light emitting element is emitted from the light emitting surface surface. It is reflected and cannot be emitted from the light emitting surface to the outside, and the luminous efficiency is lowered. On the other hand, in order to improve this, there is a semiconductor light emitting device in which the surface of the light emitting surface is roughened, that is, an uneven surface is formed on the surface of the light emitting surface. However, by making the surface of the light emitting surface rough, there arises a problem that the covering member crawls up on the light emitting surface when the coating member containing the light reflecting material is applied during the manufacturing process of the semiconductor light emitting device. In particular, when a resin is used as the covering member, a capillary phenomenon occurs on the rough surface of the light emitting surface surface, and the resin is easily spread and spread. Further, when the corners of the light emitting surface surface are rounded, the resin does not stop easily due to surface tension, and the resin easily spreads on the light emitting surface surface. As described above, the resin crawls on the surface of the light emitting surface and spreads wet, so that the surface area of the light emitting surface is narrowed and the luminous efficiency may be lowered.

The present invention has been made in view of the above circumstances, and an object of the present invention is to suppress the crawling of a covering member onto the surface of a light emitting surface and to improve the luminous efficiency.

One aspect of the present invention includes a light emitting element, a wavelength conversion layer that converts light emitted from the light emitting element into light having a predetermined wavelength, a light reflecting member that covers at least the side surface of the wavelength conversion layer, and the wavelength conversion layer. Provided is a semiconductor light emitting device provided with a thin film having a property of repelling the uncured light reflecting member, which is provided on the outermost surface from which the wavelength-converted light of the above is emitted.

In addition, another aspect of the present invention is a light emitting element, a wavelength conversion layer that converts light emitted from the light emitting element into light having a predetermined wavelength, and light transmission that transmits light wavelength-converted by the wavelength conversion layer. The uncured surface of the sex substrate, at least a light reflecting member covering the side surface of the light transmitting substrate, and the outermost surface of the light transmitting substrate from which light wavelength-converted by the wavelength conversion layer is emitted. Provided is a semiconductor light emitting device including a thin film having a property of repelling a light reflecting member.

In each of the above aspects, the surface of the thin film is rough, the contact angle of the thin film with respect to the uncured coating member is larger than the contact angle of the wavelength conversion layer and the light transmissive substrate, and the thin film is a fluororesin. The thickness of the thin film is preferably 1 nm to 10 μm, more preferably 50 nm to 1 μm. Further, it is preferable that the contact angle of the thin film is 40 ° or more.

According to the present invention, it is possible to suppress the crawling of the covering member onto the surface of the light emitting surface and improve the luminous efficiency.

A schematic configuration of the semiconductor light emitting device according to the first embodiment of the present invention is shown, (A) is a cross-sectional view, and (B) is a top view. A schematic configuration of a semiconductor light emitting device according to another example of the first embodiment of the present invention is shown, (A) is a cross-sectional view, and (B) is a top view. A schematic configuration of a semiconductor light emitting device according to another example of the first embodiment of the present invention is shown, (A) is a cross-sectional view, and (B) is a top view. It is sectional drawing which shows the schematic structure of the semiconductor light emitting device which concerns on 2nd Embodiment of this invention. It is a top view which shows the schematic structure when the wire bonding type light emitting element is applied in the semiconductor light emitting device which concerns on 1st Embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings shown below, hatching is omitted as appropriate even in the cross-sectional view for easy understanding and improvement of visibility. Further, in the top view of the semiconductor light emitting device, the configuration that cannot be visually recognized from the top view is shown by a broken line, and hatching or the like is added for convenience of explanation. Further, in the following description, even when different embodiments or modifications are made, the same reference numerals are given to the same configurations, and the description thereof will be omitted.

(First Embodiment)
The semiconductor light emitting device according to the first embodiment of the present invention will be described.
The semiconductor light emitting device according to the present embodiment includes a light emitting element 10, a wavelength conversion layer 12 that converts light emitted from the light emitting element into light having a predetermined wavelength, a light reflecting member that covers at least a side surface of the wavelength conversion layer, and a wavelength. It is provided on the outermost surface from which light wavelength-converted by the conversion layer is emitted, and includes a thin film having a rough surface and a larger contact angle than the wavelength conversion layer.

More specifically, FIG. 1A is a sectional view of the semiconductor light emitting device 1, FIG. 1B is a top view of the semiconductor light emitting device 1, and as shown in FIG. 1, the semiconductor light emitting device 1 emits light. It includes an element 10, a mounting substrate 11 on which the light emitting element 10 is mounted, a wavelength conversion layer 12, a light reflecting member 13, and a thin film 14.

The light emitting element 10 has a rectangular shape when viewed from above, and has a flip-chip structure in which a semiconductor layer and a light emitting layer are laminated on a substrate transparent to the emitted light, and an electrode for feeding is formed and inverted. ing. The light emitting element 10 irradiates the light emitted from the light emitting layer to the outside. Therefore, the upper surface and the side surface of the light emitting element 10 are light emitting surfaces. The electrodes of the light emitting element 10 are electrically connected to the wiring pattern on the mounting substrate 11 by bumps or the like (not shown).

In the present embodiment, the mounting substrate 11 is a plate-shaped body made of a ceramic material, and a plate-shaped substrate made of aluminum nitride is applied. The substrate is generally formed of an insulating material such as glass epoxy, resin, or ceramics, or a composite material of an insulating material and a metal member. As the substrate, those using ceramics or resin having high heat resistance and weather resistance are preferable.
A wiring pattern (not shown) is formed on the mounting board 11. The wiring pattern is mainly formed on the surface of the mounting substrate 11 as a mounting pattern of the light emitting element 10 and a current routing pattern for supplying power to the light emitting element 10. As the wiring pattern, a conductive material such as Al, Ni, Cu, Ag, or Au can be used.

The wavelength conversion layer 12 contains a phosphor that converts the light emitted from the light emitting element 10 into light having a desired wavelength, and is provided on the upper surface of the light emitting element 10. More specifically, the wavelength conversion layer 12 includes, for example, a mixture or sintered body of ceramic and a phosphor, a mixture of glass and a phosphor, a ceramic on which a phosphor film is arranged, a glass on which a phosphor film is formed, and fluorescence. A body-dispersed glass, a fluorescent ceramic plate, or the like can be applied. In the present embodiment, the wavelength conversion layer 12 has substantially the same size as the light emitting surface on the upper surface of the light emitting element 10, and the upper surface is a rough surface. The thickness of the wavelength conversion layer is preferably, for example, about 10 μm to 500 μm, particularly preferably about 30 μm to 250 μm.

The light reflecting member 13 is provided so as to cover the side surface of the wavelength conversion layer 12 and expose the upper surface of the wavelength conversion layer 12 to the outside. As the light reflecting member 13, for example, a silicone resin mixed with a predetermined amount of a light reflecting filler (for example, titanium oxide, aluminum oxide, zirconium oxide, zinc oxide, etc.) can be applied.

The thin film 14 is provided on the outermost surface of the semiconductor light emitting device. In the present embodiment, it is provided on the upper surface of the wavelength conversion layer 12, and is provided on the rough surface of the upper surface of the wavelength conversion layer 12 with a uniform film thickness. Therefore, the surface of the thin film 14 is a rough surface. Further, as the thin film 14, a material having a larger contact angle with respect to the uncured light reflecting member than the wavelength conversion layer 12 is selected and applied. More specifically, as the thin film 14, a material that repels the light reflecting member 13 in a liquid state before curing is applied. Further, it is preferable that the contact angle of the thin film 14 with water is 40 ° or more. For example, by applying a material having excellent non-adhesiveness and slipperiness such as fluororesin, the contact angle of water can be maintained at 40 ° or more. In addition, an organic substance such as organoepoxy can be applied as the thin film 14.

The film thickness of the thin film is preferably 1 nm to 10 μm, more preferably 50 nm to 1 μm, and even more preferably 50 nm to 100 nm. In the present embodiment, since the upper surface of the wavelength conversion layer 12 is a rough surface, by making a profit on the wavelength conversion layer 12 with a uniform film thickness, the thin film 14 follows the unevenness of the wavelength conversion layer 12. The upper surface is also a rough surface that maintains unevenness. The thin film 14 is preferably formed in advance on the upper surface of the wavelength conversion layer 12 by, for example, a spin coater or a spray.

The semiconductor light emitting device configured in this way is manufactured as follows.
Prior to manufacturing the semiconductor light emitting device, a thin film 14 made of a fluororesin is formed on a phosphor ceramic plate to be a wavelength conversion layer 12. The fluoroceramic plate is preliminarily adjusted in phosphor concentration and thickness, and is cut into a desired size after the thin film 14 is formed. In the present embodiment, the phosphor ceramic plate to be the wavelength conversion layer 12 is cut to have substantially the same size as the upper surface of the light emitting element 10.

Then, the light emitting element 10 is mounted on the mounting substrate 11 on which the wiring pattern (not shown) is formed in advance via bumps (not shown). Next, a phosphor ceramic plate on which a thin film 14 is formed in advance and cut to substantially the same size as the upper surface of the light emitting element 10 is coated with a resin for adhering the phosphor ceramic plate and mounted on the upper surface of the light emitting element 10 to heat the resin. It is cured to form a wavelength conversion layer 12 and a thin film 14.

Next, a light-reflecting member in which a predetermined amount of a light-reflecting filler is mixed with an uncured silicone resin is poured onto the mounting substrate 11 until the side surfaces of the light emitting element 10 and the wavelength conversion layer 12 are completely surrounded. At this time, the boundary between the wavelength conversion layer 12 and the light reflection member 13 of the poured light reflecting member 13 is the highest, and gradually decreases as the distance from the wavelength conversion layer 12 increases. When the semiconductor light emitting device has a cavity, the height increases from the lowered portion toward the upper surface of the cavity, and when the upper surface of the cavity is higher than the wavelength conversion layer, the height of the covering member is the highest at the cavity and the connection portion.

In this way, in the light reflecting member 13, the light reflecting member 13 crawls up to the wavelength conversion layer 12 side, causes a capillary phenomenon on the rough surface of the wavelength conversion layer 12, and tries to get wet and spread. However, since the thin film 14 that repels the uncured light reflecting member 13 is formed on the upper surface of the wavelength conversion layer 12, it is suppressed that the light reflecting member 13 crawls up to the wavelength conversion layer 12 and spreads wet. In this state, the light reflecting member 13 is cured by an appropriate curing method such as heating or ultraviolet irradiation, and dicing cut to a predetermined size so that the light reflecting member 13 is individualized as a structure covering the side surface of the wavelength conversion layer 12. The semiconductor light emitting device can be manufactured.
In this way, the light reflecting member 13 is prevented from crawling up to the wavelength conversion layer 12 and spreading wet, so that the rough surface shape of the upper surface of the wavelength conversion layer 12 is maintained and the luminous efficiency due to the crawling up of the light reflecting member 12 is maintained. It is possible to suppress the decrease in brightness and the decrease in brightness.

In the present embodiment, an example in which the wavelength conversion layer 12 has substantially the same size as the upper surface of the light emitting element 10 has been described. For example, as shown in FIGS. 2A and 2B, the wavelength conversion layer 12 emits light. The size may be smaller than the upper surface of the element 10. Further, as shown in FIGS. 3A and 3B, the wavelength conversion layer 12 may have a size larger than the upper surface of the light emitting element 10.
Further, when the surface of the wavelength conversion layer 12 is not a rough surface but a flat surface, by making the surface of the thin film 14 a rough surface, the light reflecting member 13 also crawls up to the wavelength conversion layer 12 and spreads wet. Can be suppressed, and a decrease in luminous efficiency and a decrease in brightness can be suppressed.

When the thin film 14 is formed on the upper surface of the wavelength conversion layer 12, it is conceivable that the thin film 14 is formed thick in the concave portion on the rough surface and thin in the convex portion, and the uneven shape becomes slightly gentle. In such a case, the rough surface is not completely flat, and the uneven shape of the rough surface can be maintained, so that the luminous efficiency can be maintained.

(Second Embodiment)
Next, the semiconductor light emitting device according to the second embodiment of the present invention will be described.
In the first embodiment of the present invention described above, an example of forming a thin film on the upper surface of the wavelength conversion layer 12 has been described. In the present embodiment, an example in which the semiconductor light emitting device includes a light-transmitting substrate and the thin film 14 is formed on the light-transmitting substrate will be described. FIG. 4 is a cross-sectional view of the semiconductor light emitting device according to the present embodiment. In the following description, the same components as those in the first embodiment described above will be designated by the same reference numerals, and the description thereof will be omitted.

The semiconductor light emitting device according to the present embodiment transmits the light emitting element 10, the wavelength conversion layer 12 that converts the light emitted from the light emitting element 10 into light of a predetermined wavelength, and the light wavelength-converted by the wavelength conversion layer 12. The light transmissive substrate 15, the light reflecting member 13 covering at least the side surface of the light transmissive substrate 15, and the outermost surface from which the light wavelength-converted by the wavelength conversion layer 12 is emitted are provided, and the surface is a rough surface and transmits light. A thin film having a contact angle larger than that of the sex substrate 15 is provided.

The light transmissive substrate 15 is made of, for example, glass, sapphire, silicone resin, etc., has substantially the same area as the wavelength conversion layer 12 in the present embodiment, and is arranged on the upper surface of the wavelength conversion layer 12.
The thin film 14 is provided on the outermost surface of the semiconductor light emitting device, as in the first embodiment described above. Therefore, in the present embodiment, it is provided on the upper surface of the light transmissive substrate 15, and is provided on the rough surface of the upper surface of the light transmissive substrate 15 with a uniform film thickness. Therefore, the surface of the thin film 14 is a rough surface. Further, as the thin film 14, a material having a larger contact angle with respect to the uncured light reflecting member than the light transmitting substrate 15 is selected and applied. More specifically, as the thin film 14, a material that repels the light reflecting member 13 in a liquid state before curing and has a contact angle with water of 40 ° or more is applied. For example, by applying a material having excellent non-adhesiveness and slipperiness such as fluororesin, the contact angle of water can be maintained at 40 ° or more.

The film thickness of the thin film is preferably 1 nm to 10 μm, more preferably 50 nm to 1 μm. In the present embodiment, since the upper surface of the light-transmitting substrate 15 is a rough surface, the thin film 14 is made profitable on the wavelength conversion layer 12 with a uniform film thickness, so that the thin film follows the unevenness of the light-transmitting substrate 15. The upper surface of 14 is also a rough surface that maintains unevenness. The thin film 14 is preferably formed in advance on the upper surface of the light transmissive substrate 15 by, for example, a spin coater or a spray.

The semiconductor light emitting device configured in this way is manufactured as follows.
Prior to the manufacture of the semiconductor light emitting device, a thin film 14 made of fluororesin is formed on a plate-shaped member such as glass to be a light transmissive substrate 15. The light-transmitting substrate 15 is cut to a desired size after the thin film 14 is formed. In the present embodiment, the light transmissive substrate 15 is cut to have substantially the same size as the upper surfaces of the light emitting element 10 and the wavelength conversion layer 12.
Then, the light emitting element 10 is mounted on the mounting substrate 11 on which the wiring pattern (not shown) is formed in advance via bumps (not shown). Next, the phosphor ceramic plate is coated with a resin for adhering the phosphor ceramic plate and mounted on the upper surface of the light emitting element 10, and the resin for adhering the phosphor ceramic plate is coated to form the wavelength conversion layer 12. Subsequently, the light transmissive substrate 15 having the thin film 14 formed on the upper surface of the wavelength conversion layer 12 is mounted and fixed.

Next, a light-reflecting member in which a predetermined amount of a light-reflecting filler is mixed with a silicone resin in advance is poured onto the mounting substrate 11 until the side surfaces of the light-emitting element 10 and the light-transmitting substrate 15 are completely surrounded. At this time, the light-reflecting member 13 poured into the light-transmitting member 13 has the highest boundary between the light-transmitting substrate 15 and the light-transmitting member 13, and gradually decreases as the distance from the light-transmitting substrate 15 increases.

The light-reflecting member 13 crawls up to the light-transmitting substrate 15 side, causes a capillary phenomenon on the rough surface of the light-transmitting substrate 15, and tries to get wet and spread. However, since the thin film 14 that repels the light reflecting member is formed on the upper surface of the light transmitting substrate 15, the light reflecting member 13 is prevented from crawling up to the wavelength conversion layer 12 and spreading wet. In this state, the semiconductor light emitting device is manufactured as a structure in which the light reflecting member 13 covers the side surface of the light transmitting substrate 15 by heating and curing the light-transmitting member 13 and cutting the dicing to a predetermined size.
In this way, since the light reflecting member 13 is prevented from crawling up on the light transmitting substrate 15 and spreading wet, it is possible to suppress a decrease in luminous efficiency and a decrease in brightness due to the crawling up of the light reflecting member. ..

Note that FIG. 5 shows an example in which a wire bonding type light emitting element that supplies power via a bonding wire connected to the upper surface of the light emitting element is applied. In FIG. 5, the wavelength conversion layer 12 is arranged on the upper surface of the light emitting element 10, that is, on the light emitting surface side. In this example, in order to arrange the wire on the upper surface of the light emitting element 10, a notch 12A for letting the wire escape is formed in the wavelength conversion layer 12. In the figure, a notch is provided at the center of any one side of the wavelength conversion layer 12, but the position of the notch can be appropriately determined such as the center of the element, the corner, and the side, and the number of wires is one. Multiple pieces can be set as appropriate.

The semiconductor light emitting device according to each of the above-described embodiments can be applied to a light source of a headlamp or an ADB (Adaptive Driving Beam) type vehicle lighting device, and can also be applied to a general lighting device for lighting or the like. ..
The height of the light reflecting member 13 tends to decrease as the distance from the wavelength conversion layer 12 or the light transmitting substrate 15 increases, and when this becomes remarkable, the light from the side surface of the wavelength conversion layer 12 or the light transmitting substrate 15 tends to decrease. Leakage increases and glare problems occur when semiconductor light emitting devices are applied to, for example, vehicle lighting fixtures. By providing the thin film 14 in each of the above-described embodiments, the height of the light reflecting member 13 can be increased, so that the shape of the light reflecting member 13 is substantially flat with respect to the wavelength conversion layer 12 or the light transmitting substrate 15. It can be shaped to spread out. This makes it possible to avoid the problem of glare when used in vehicle headlights.

10 ... light emitting element, 11 ... mounting substrate, 12 ... wavelength conversion layer, 13 ... light reflecting member, 14 ... thin film, 15 ... light transmissive substrate

Claims (9)

A light emitting element having an upper surface and a side surface and having a rectangular top view ,
A mounting board on which the light emitting element is mounted and
A plate-shaped wavelength conversion layer arranged on the light emitting element and having an upper surface, a lower surface and a side surface ,
A light reflecting member formed on the mounting substrate and covering the side surface of the wavelength conversion layer and the side surface of the light emitting element .
A thin film provided on the upper surface of the wavelength conversion layer is provided.
The wavelength conversion layer contains a fluorescent material that converts the light emitted from the light emitting element into light having a desired wavelength, and includes a mixture of ceramic and fluorescent material, a sintered body of ceramic and fluorescent material, and a mixture of glass and fluorescent material. It consists of a ceramic on which a fluorescent material film is placed, a glass on which a fluorescent material film is formed, a fluorescent material dispersed glass, or a fluorescent material ceramic plate.
The light-reflecting member has an upper surface, an inner side surface, and an outer side surface having a rectangular side view, and is made of a cured product of the light-reflecting member obtained by mixing a predetermined amount of a light-reflecting filler with an uncured resin material.
The inner side surface of the light reflecting member surrounds the side surface of the wavelength conversion layer and the side surface of the light emitting element to form a boundary portion between the wavelength conversion layer and the light reflecting member.
The outer side surface of the light reflecting member faces the inner side surface of the light reflecting member.
The shape of the light reflecting member is a shape that spreads substantially flat with respect to the mounting substrate.
The thin film is a resin film located on the outermost surface of the wavelength conversion layer from which wavelength-converted light is emitted and has a property of repelling the uncured light-reflecting member.
The upper surface of the wavelength conversion layer has a rough surface for improving external emission efficiency.
The thin film follows the unevenness of the rough surface of the wavelength conversion layer, and the upper surface of the thin film is provided so as to be a rough surface that maintains the unevenness of the upper surface of the wavelength conversion layer.
A semiconductor light emitting device having a thin film thickness of 50 nm to 1 μm . The semiconductor light emitting device according to claim 1, wherein the light reflecting member is in contact with an end portion of the thin film, and the thin film suppresses creeping up to the upper surface of the wavelength conversion layer and wet spreading at the end portion. The semiconductor light emitting device according to claim 1 or 2, wherein the thin film is made of a material having a contact angle with water of 40 ° or more. The semiconductor light emitting device according to any one of claims 1 to 3 , wherein the thin film is made of a fluororesin. The semiconductor light emitting device according to any one of claims 1 to 4, wherein the light reflecting member is formed by mixing the light reflecting filler with a silicone resin. The semiconductor light emitting device according to any one of claims 1 to 5, wherein the wavelength conversion layer is arranged on the upper surface of the light emitting element via an adhesive resin. The upper surface of the wavelength conversion plate having a rough surface on the entire upper surface has a rough surface that follows the unevenness of the rough surface and maintains the unevenness on the upper surface, and has a property of repelling uncured resin. A step of forming a thin film having a thickness of 50 nm to 1 μm with a resin and preparing the wavelength conversion plate with the thin film.
A process of applying an adhesive resin to the upper surface of a light emitting element mounted on a mounting substrate and mounting the wavelength conversion plate with a thin film.
By pouring an uncured resin mixed with a light-reflecting filler onto the mounting substrate, the thin film on the upper surface of the wavelength conversion plate allows the thin film from the side surface of the wavelength conversion plate of the uncured resin. The step of surrounding the light emitting element and the side surface of the wavelength conversion plate with the light reflecting member while suppressing the creeping up to the upper surface of the
By curing the uncured resin, the side surfaces of the light emitting element and the wavelength conversion plate are surrounded, and the resin does not crawl up on the upper surface of the thin film on the upper surface of the wavelength conversion plate. With the process of forming members
A method for manufacturing a semiconductor light emitting device having the above. The step of preparing the wavelength conversion plate with the thin film is
A step of forming the thin film made of fluororesin on the wavelength conversion plate, and
A step of cutting the wavelength conversion plate with a thin film to separate it into individual pieces.
The method for manufacturing a semiconductor light emitting device according to claim 7. The wavelength conversion plate contains a fluorescent material that converts the light emitted from the light emitting element into light having a desired wavelength, and includes a mixture of ceramic and fluorescent material, a sintered body of ceramic and fluorescent material, and a mixture of glass and fluorescent material. The method for manufacturing a semiconductor light emitting device according to claim 7 or 8, which comprises any of a ceramic on which a fluorescent material film is arranged, a glass on which a fluorescent material film is formed, a phosphor-dispersed glass, and a fluorescent material ceramic plate.

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