JP6025138B2 - Light emitting device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a light emitting device having a wavelength conversion layer containing a plurality of phosphor particles on a semiconductor layer forming a light emitting element, and a method for manufacturing the same.

  A wavelength conversion layer composed of a resin layer containing a plurality of phosphor particles is formed on a semiconductor layer that constitutes a light emitting element such as a light emitting diode, and a part of light from the semiconductor layer differs depending on the phosphor particles in the wavelength conversion layer. There is known a light emitting device that converts light into a wavelength and emits light after being converted by phosphor particles by mixing with light passing through a wavelength conversion layer from a semiconductor layer (see, for example, Patent Document 1).

  In such a light emitting device, in general, in order to form a wavelength conversion layer, a resin containing phosphor particles is sprayed on the main surface on the light emission side of the semiconductor layer and cured. It is desirable that the phosphor particles in the wavelength conversion layer are uniformly distributed over the entire upper surface of the semiconductor layer so that the amount of incident light from the semiconductor layer is not wavelength-converted and is emitted as it is. . For this reason, for example, Patent Document 2 shows that a coating liquid containing a phosphor is sprayed from above the light emitting element while rotating in a mist-like and spiral manner.

JP 2009-111245 A JP 2003-115614 A

  However, in such a conventional light emitting device, even when a device such as a spiral coating as in Patent Document 2 is applied when the resin containing phosphor particles is uniformly applied to the upper surface of the semiconductor layer by spraying, At the edge of the semiconductor layer, the phosphor particles fired by the spray do not stay on the edge, the phosphor particles fall from the semiconductor layer, and the surface tension between the resin and the edge of the semiconductor layer Due to the difference, the resin itself may not be sufficiently disposed at the end of the semiconductor layer. For this reason, the layer thickness at the end of the wavelength conversion layer is reduced, and there is a problem that color unevenness occurs in the light emitted from the light emitting device.

  Accordingly, an object of the present invention has been made in view of such a point, and it is possible to prevent color unevenness by forming a wavelength conversion layer on a semiconductor layer so that the phosphor particles stay up to the end of the semiconductor layer. It is providing the light-emitting device which can be manufactured, and its manufacturing method.

The light emitting device of the present invention is a light emitting device comprising a substrate, a semiconductor layer disposed on the substrate and including a light emitting layer, and a wavelength conversion layer including a plurality of phosphor particles disposed on the semiconductor layer. A step portion extending to at least the substrate at an end portion of the semiconductor layer, and a width of the step portion extending from a side surface position of the semiconductor layer to a side of the substrate is more than half of an average particle diameter of the phosphor particles. large, the depth of the stepped portion is an average smaller than the diameter Kuna' of the phosphor particles, the surface of the substrate forming the bottom surface of the stepped portion is characterized by being roughened.
The light emitting device of the present invention is a light emitting device comprising a substrate, a semiconductor layer disposed on the substrate and including a light emitting layer, and a wavelength conversion layer including a plurality of phosphor particles disposed on the semiconductor layer. A step portion extending to at least the substrate at an end portion of the semiconductor layer, and a width of the step portion extending from a side surface position of the semiconductor layer to a side of the substrate is more than half of an average particle diameter of the phosphor particles. The depth of the stepped portion is smaller than the average particle diameter of the phosphor particles, and at least the side surface of the substrate facing the stepped portion has an inverted mesa shape.
The light emitting device of the present invention is a light emitting device comprising a substrate, a semiconductor layer disposed on the substrate and including a light emitting layer, and a wavelength conversion layer including a plurality of phosphor particles disposed on the semiconductor layer. A step portion extending to at least the substrate at an end portion of the semiconductor layer, and a width of the step portion extending from a side surface position of the semiconductor layer to a side of the substrate is more than half of an average particle diameter of the phosphor particles. The depth of the stepped portion is smaller than the average particle diameter of the phosphor particles, and the stepped portion has a recess along the side direction of the substrate on the substrate forming the bottom surface. It is said.
The light emitting device of the present invention is a light emitting device comprising a substrate, a semiconductor layer disposed on the substrate and including a light emitting layer, and a wavelength conversion layer including a plurality of phosphor particles disposed on the semiconductor layer. A step portion extending to at least the substrate at an end portion of the semiconductor layer, and a width of the step portion extending from a side surface position of the semiconductor layer to a side of the substrate is more than half of an average particle diameter of the phosphor particles. The depth of the stepped portion is smaller than the average particle diameter of the phosphor particles, and the stepped portion is a plurality of dimples arranged along the side direction of the substrate on the substrate forming the bottom surface. It is characterized by having holes.

A method for manufacturing a light-emitting device according to the present invention provides a light-emitting element including a substrate and a semiconductor layer including a light-emitting layer formed on the substrate, and having a step portion at least reaching the substrate at an end of the semiconductor layer. And a step of spraying a coating liquid containing phosphor particles from above the light emitting element to form a wavelength conversion layer on the upper surface of the light emitting element, and from the side surface position of the semiconductor layer to the substrate The width of the step portion reaching the side of the phosphor is formed to be larger than half of the average particle diameter of the phosphor particles, the depth of the step portion is formed to be smaller than the average particle diameter of the phosphor particles, and the step portion The surface of the substrate that forms the bottom surface of the substrate is roughened .

  According to the light emitting device and the method for manufacturing the same of the present invention, a stepped portion reaching at least the substrate is formed at the end of the semiconductor layer, and the stepped portion has such a width and depth that the phosphor particles stay on the stepped portion. When forming the wavelength conversion layer, the phosphor particles applied to the step portion together with a binder such as a resin stays on the step portion, and a bank of the remaining phosphor particles can be formed on the step portion. As a result, the phosphor particles remain on the edge of the semiconductor layer, so that the distribution of the phosphor particles in the wavelength conversion layer on the semiconductor layer can be made uniform, and the layer thickness of the wavelength conversion layer Can be formed uniformly up to the end of the semiconductor layer. Therefore, since wavelength conversion is performed by the wavelength conversion layer over the entire area on the semiconductor layer, color unevenness of light emitted from the wavelength conversion layer can be prevented.

It is sectional drawing which shows the light-emitting device of Example 1 of this invention. It is a figure which shows the spray injection of the 1st binder liquid containing the fluorescent substance particle in the manufacture process of the light-emitting device of Example 1. FIG. FIG. 4 is a cross-sectional view showing the width, depth, and angle of a step portion of the light emitting device of Example 1. FIG. 3 is an external view showing the arrangement of phosphor particles at a step portion and an end portion of a semiconductor layer of the light emitting device of Example 1. It is a characteristic view which shows the relationship between the width | variety of a level | step-difference part, and the occupation rate of the fluorescent substance particle in the edge part of a semiconductor layer. 6 is a cross-sectional view showing a method for manufacturing the light-emitting device of Example 1. FIG. It is sectional drawing which shows the rough surface on the board | substrate which forms the bottom face of a level | step-difference part as Example 2 of this invention. It is sectional drawing which shows the light-emitting device of Example 2 in which the wavelength conversion layer was formed. It is sectional drawing which shows the light-emitting device of Example 3 of this invention. It is sectional drawing which shows the light-emitting device of Example 4 of this invention. It is sectional drawing which shows the light-emitting device of Example 5 of this invention. It is sectional drawing which shows the other formation method of the wavelength conversion layer as Example 6 of this invention. It is sectional drawing which shows the light-emitting device of Example 7 of this invention. 10 is a cross-sectional view showing a method for forming a recess in Example 7. FIG. It is sectional drawing which shows the light-emitting device of Example 8 of this invention. It is a figure which shows the external appearance on the surface side of the semiconductor layer before forming a wavelength conversion layer as Example 9 of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a cross-sectional view of a light-emitting device as Example 1 of the present invention. In this light emitting device, a wavelength conversion layer 13 is formed on a light emitting element composed of a substrate 10 and a semiconductor layer 11. The substrate 10 is a silicon substrate, and a semiconductor layer 11 including a light emitting layer formed as a GaN-based epitaxial layer is disposed on the substrate 10. The light emitting element is a metal bonding type light emitting element (light emitting diode), and the semiconductor layer 11 is metal-bonded to the substrate 10.

  A step 12 is formed at the end of the semiconductor layer 11. The bottom of the stepped portion 12 reaches the inside of the substrate 10. A wavelength conversion layer 13 is formed on the upper surface of the semiconductor layer 11 including the step portion 12.

  A large number of phosphor particles 14 are dispersed in the wavelength conversion layer 13. The phosphor particles 14 are, for example, YAG phosphor particles that are excited by light emitted from the semiconductor layer 11 and emit fluorescence of a predetermined wavelength. As the base material of the wavelength conversion layer 13, binders 14 a and 14 b having a light-transmitting property with respect to the fluorescence emitted from the phosphor particles 14 are used together with the light emitted from the semiconductor layer 11. As the binder 14a, an inorganic material (silicate compound) such as glass, or a transparent resin such as dimethyl silicone or phenyl silicone can be used, or a mixture thereof may be used. The binder 14 b is a glass binder for filling the gaps between the phosphor particles 14. As shown in FIG. 2, the binders 14 a and 14 b are formed by spraying and applying a liquid in a spray 21 onto the upper surface of the semiconductor layer 11 including the stepped portion 12 and drying it. It is a thing. Each of the binders 14a and 14b is liquefied by a volatile organic solvent such as alcohol or xylene for injection by the spray 21. In the following description, the liquefied binder 14a is the first binder liquid, and the liquefied binder 14b is the second binder liquid. The first binder liquid contains a large number of phosphor particles 14.

  FIG. 3 shows the width, depth, and angle of the step portion 12, and the step portion 12 has a width, a depth, and a depth so that the phosphor particles 14 are positioned on the step portion 12 by the injection of the first binder liquid. And the angle is determined. The width of the stepped portion 12 is the length from the side surface position of the semiconductor layer 11 to the side of the substrate 10 and is set to be larger than half of the average particle size of the phosphor particles 14. The depth of the step portion 12 is the distance between the upper surface position of the substrate and the upper surface position of the semiconductor layer 11 in the step portion 12, that is, the position where the phosphor particles 14 arranged in the step portion 12 are in contact with the substrate and the semiconductor layer 11. It is the distance from the upper surface position, and is set smaller than the average particle diameter of the phosphor particles 14. That is, the depth of the step portion 12 is designed so that the phosphor particles 14 arranged in the step portion 12 protrude from the upper surface of the semiconductor layer 11. For example, if the average particle diameter of the phosphor particles 14 is 15 μm, the width is larger than 7.5 μm and the depth is smaller than 15 μm. The width of the step is preferably equal to or greater than the average particle diameter of the phosphor particles 14, and the depth of the step is preferably ½ or less of the average particle diameter of the phosphor particles 14, and more preferably, the width of the step is the width of the phosphor particles 14. The average particle size is preferably 1.5 times or more. The angle of the stepped portion 12 may be 100 degrees or less, and the bottom surface roughness (roughness of the silicon substrate) of the stepped portion 12 is preferably determined to be Ra 0.1 μm or more. By forming the step portion 12 having such a width, depth, angle, and bottom surface roughness, the phosphor particles 14 ejected by the first binder liquid can easily stay on the step portion 12. In addition, each value of the level | step-difference part 12 shown here is an example, and this invention is not limited to these values.

  Since the phosphor particles 14 stay in the step portion 12 and the phosphor particles 14 in the step portion 12 protrude from the surface of the semiconductor layer 11, as shown in FIGS. 1 and 4, the fluorescence in the step portion 12. The body particles 14 are suppressed, and the phosphor particles 14 are likely to remain on the end portions of the semiconductor layer 11.

  FIG. 5 shows the relationship between the width of the stepped portion 12 and the phosphor occupancy ratio of the phosphor particles 14 on the end portion of the semiconductor layer 11 as a characteristic. Semiconductor in the case where the depth and width of the step portion 12 are changed using phosphor particles 14 having an average particle size (volume average calculated from the particle size distribution obtained by laser diffraction / scattering method before adjusting the coating solution). The phosphor occupancy ratio on the end portion of the layer 11 (ratio in which the end portion of the semiconductor layer 11 is covered with the phosphor particles 14) is shown. From this result, it can be seen that the phosphor occupancy on the end portion of the semiconductor layer 11 can be increased as the width of the stepped portion 12 is increased. It can also be seen that the phosphor occupancy on the end portion of the semiconductor layer 11 can be increased as the depth of the stepped portion 12 is shallower. In particular, it has been found that even if the width of the narrow step portion 12 is small, if the depth of the step portion 12 is reduced, a high phosphor occupancy ratio on the end portion of the semiconductor layer 11 can be secured.

  When the depth of the stepped portion 12 is 8 μm, which is about ½ (more precisely 8/15) of the average particle diameter (volume average) of the phosphor particles 14, the width of the stepped portion 12 is about 23 μm (phosphor particles). The average particle size of the phosphor 14 is 90% and the width of the step 12 is about 30 μm (about twice the average particle size of the phosphor particles 14). %Met. That is, by setting the depth of the stepped portion 12 to 8/15 or less of the average particle diameter of the phosphor particles, even when the width of the stepped portion 12 is less than twice the average particle diameter of the phosphor particles 14, a high phosphor Occupancy rate can be obtained. Here, since the width of the stepped portion 12 affects the formation region of the semiconductor layer 11 on the substrate 10, it is preferable that the width of the stepped portion 12 is small if the phosphor occupancy on the end portion of the semiconductor layer 11 is increased. Therefore, the depth of the stepped portion 12 is preferably 8/15 or less of the average particle diameter of the phosphor particles 14.

  When the depth of the stepped portion 12 is 3 μm, which is 1/5 of the average particle size (volume average) of the phosphor particles 14, the width of the stepped portion 12 is about 10 μm (2/3 of the average particle size of the phosphor particles 14). ), The phosphor occupancy was 90%. That is, if the depth of the step portion 12 is 1/5 or more of the average particle diameter of the phosphor particles, the phosphor having a width of the step portion 12 that is 2/3 or more of the average particle diameter of the relatively narrow phosphor particles 14 is high. Occupancy rate can be obtained. Therefore, the depth of the stepped portion 12 is preferably set to 1/5 or more of the average particle diameter of the phosphor particles 14.

  In the case where the depth of the stepped portion 12 is 15 μm, which is the average particle size (volume average) of the phosphor particles 14, the phosphor occupancy tends to increase as the width of the stepped portion 12 is increased, but 60 μm ( The phosphor occupancy was 60% or less even at 4 times the average particle diameter of the phosphor particles. Therefore, the depth of the stepped portion 12 is preferably smaller than the average particle diameter of the phosphor particles 14.

  In the light emitting device of Example 1 having such a configuration, light emitted upward from the semiconductor layer 11 is incident on the wavelength conversion layer 13, and a part thereof is converted into light of a predetermined wavelength by the phosphor particles 14, thereby It is mixed with the light that has not been converted by the body particles 14 and emitted. Similarly, the light emitted from the side surface of the semiconductor layer 11 is incident on the wavelength conversion layer 13 of the step portion 12, and a part thereof is converted into light of a predetermined wavelength by the phosphor particles 14 of the step portion 12, and the phosphor It is mixed and emitted with the light that has not been converted by the particles 14.

  As described above, according to the light emitting device of Example 1, the stepped portion 12 is formed at the end of the semiconductor layer 11, whereby the phosphor particles 14 are formed by spray application of the first binder liquid for forming the wavelength conversion layer 13. Remains on the stepped portion 12, and a bank of phosphor particles 14 is formed on the stepped portion 12. As a result, the phosphor particles 14 remain at the end of the semiconductor layer 11, so that the distribution of the phosphor particles 14 in the wavelength conversion layer 13 covering the semiconductor layer 11 can be made uniform, and the wavelength conversion can be performed. The layer 13 can be formed to have a constant thickness up to the end of the semiconductor layer 11.

  Therefore, color unevenness of light emitted from the wavelength conversion layer 13 can be suppressed. For example, if the emission color of the semiconductor layer 11 is blue and the phosphor particles 14 convert blue light into yellow light, white light is emitted from the wavelength conversion layer 13. In particular, blue light leakage from the upper surface position of the wavelength conversion layer 13 corresponding to the end of the semiconductor layer 11 can be reduced. Similarly, since the blue light emitted from the side surface of the semiconductor layer 11 is converted into yellow light by the phosphor particles 14 in the stepped portion 12, the blue light leakage can be reduced also on the side surface of the semiconductor layer 11. In the present invention, the emission color of the semiconductor layer 11 is not limited to blue, and the conversion color of the wavelength conversion layer 13 is not limited to yellow.

  6A to 6F show a method for manufacturing the light emitting device of Example 1 of FIG. The light emitting device is manufactured in the order of FIGS. That is, an epi layer bonding process, a resist formation process, an etching process, a cutting process, a first binder coating process, and a second binder coating process are performed.

  In the epi layer bonding step, as shown in FIG. 6A, the substrate material 31 corresponding to the substrate 10 and the epitaxial layer 32 corresponding to the semiconductor layer 11 are joined by fusion bonding between metal bonding layers (not shown). Since the epitaxial layer 32 is formed by the conventional technique, the description here is omitted.

  In the resist formation step, as shown in FIG. 6B, a resist 33 is formed on the epitaxial layer 32 in units of devices. That is, the portion of the epitaxial layer 32 on which the resist 33 is formed is left as the semiconductor layer 11.

  In the etching step, as shown in FIG. 6C, for example, a portion of the epitaxial layer 32 that is not masked by the resist 33 is etched using a wet etching method. In this etching, the substrate material 31 (including the above-mentioned fusion bonded metal adhesive layer) is also etched together with the epitaxial layer 32 to form the recess 34. The depth of the concave portion 34 corresponds to the groove depth of the stepped portion 12. The resist 33 is removed after the etching. The epitaxial layer 32 is divided into device units corresponding to the semiconductor layer 11 by etching.

  In the cutting step, the substrate material 31 is divided into device units. The cutting position is the central portion of the recess 34 as indicated by a broken line in FIG. As a result of this cutting, the above-described substrate 10, semiconductor layer 11, and stepped portion 12 are obtained in units of devices. The process so far includes a substrate 10 and a semiconductor layer 11 including a light emitting layer formed on the substrate 10, and a step of preparing a light emitting element having a step 12 at least reaching the substrate 10 at an end of the semiconductor layer 11. It is.

  In the first binder application step, as shown in FIG. 6E, the first binder 35 including the phosphor particles 14 is applied in units of devices. Specifically, as shown in FIG. 2, the first binder liquid 35 is sprayed onto the upper surface of the semiconductor layer 11 including the step portion 12 by spraying. The viscosity of the first binder liquid 35 is, for example, 100 mPa · s, but may be a value within the range of 20 to 300 mPa · s. The concentration of the phosphor particles 14 in the first binder liquid 35 is, for example, 50 wt%, but may be 10 to 80 wt%. After injection, the first binder liquid 35 is dried for curing. In this first binder application step, the phosphor particles 14 are positioned on the stepped portion 12.

  In the second binder application step, as shown in FIG. 6 (f), the cured first binder 35, that is, the second binder 37 is sprayed 12 so as to fill the gaps between the phosphor particles 14 of the binder 14a. It is applied by spraying. After injection, the second binder liquid 37 is dried for curing. As a result, as shown in FIG. 1, a light emitting device including the wavelength conversion layer 13 in which the phosphor particles 14 are arranged in the stepped portion 12 is obtained. The first and second binder coating processes are processes for spraying a coating liquid containing phosphor particles 14 from above the light emitting element to form the wavelength conversion layer 13 on the upper surface of the light emitting element.

  In the first binder application step and the second binder application step in Example 1, a spray method in which the coating liquid is sprayed and sprayed is used. However, in addition to the spray method, a jet dispenser method or an electrostatic coating method is used. Can also be used.

  FIG. 7 shows a cross-sectional view of a light emitting device as a second embodiment of the present invention. In the light emitting device of Example 2, the roughness of the bottom surface of the step portion 12 is increased. That is, the surface of the substrate 11 forming the bottom surface of the stepped portion 12 is roughened to an average roughness Ra (for example, Ra 0.5 μm) of 1 μm or less, for example. This roughness is produced, for example, by a sandblast method. By increasing the roughness of the bottom surface of the stepped portion 12 in this way, the phosphor particles 14 reliably remain on the stepped portion 12 by spray application of the first binder liquid for forming the wavelength conversion layer 13, and the phosphor particles The bank by 14 can be formed in the level | step-difference part 12. FIG. Therefore, as shown in FIG. 8, the distribution of the phosphor particles 14 in the wavelength conversion layer 13 can be made uniform on the semiconductor layer 11, and the layer thickness of the wavelength conversion layer 13 is set to the end of the semiconductor layer 11. It can be formed uniformly up to the top.

  In the present embodiment, the depth corresponding to the depth of the stepped portion 12, that is, the position of the average line from which the arithmetic average roughness Ra is obtained, to the upper surface position of the semiconductor layer 11 is smaller than the particle diameter of the phosphor particles 14. Is set.

  FIG. 9 shows a cross-sectional view of a light emitting device as Example 3 of the present invention. In the light emitting device of Example 3, not only the roughness of the bottom surface of the stepped portion 12 but also the surface of the semiconductor layer 11 on which the wavelength conversion layer 13 is disposed is roughened. Thereby, the phosphor particles 14 are liable to stay on the semiconductor layer 11 as well as the stepped portion 12.

  FIG. 10 shows a cross-sectional view of a light-emitting device as Example 4 of the present invention. In the light emitting device of this Example 4, the side surface A of the substrate 10 and the semiconductor layer 11 forming the stepped portion 12 has an inverted mesa shape, and the groove angle of the stepped portion 12 is made smaller than 90 degrees. Further, phosphor particles 14c having a smaller diameter are arranged in the step portion 12 together with the phosphor particles 14 having an average particle diameter. In other words, in the stepped portion 12, the small-diameter phosphor particles 14c are positioned in contact with the side surface A of the substrate 10 and the semiconductor layer 11 having the inverted mesa shape, and the phosphor particles 14 having an average particle diameter are the phosphor particles 14c. It is in contact and outside. This reverse mesa shape allows the phosphor particles 14 (phosphor particles 14c) to be more reliably applied to the stepped portion 12 during spray application by spraying the first binder liquid. Thereby, the blue light omission from the end portion of the semiconductor layer 11, particularly the side surface, can be efficiently suppressed, so that the color unevenness can be suppressed. In general, by utilizing the fact that the phosphor particles have a particle size distribution, it is possible to efficiently suppress blue light loss and color unevenness by using the phosphor particles 14c having a diameter smaller than the average particle diameter.

  In this case, the width of the stepped portion 12 may be half of the average particle diameter of the phosphor particles 14, but a phosphor larger than the average particle diameter may be difficult to be placed on the stepped portion 12. And more preferably twice the average particle size.

  FIG. 11 shows a cross-sectional view of a light emitting device as Example 5 of the present invention. In the light emitting device of Example 5, only the side surface B of the substrate 10 on which the stepped portion 12 is formed has an inverted mesa shape. Other configurations are the same as those of the light-emitting device of Example 4 in FIG. As a result, it is possible to prevent blue from coming out from the end portion of the semiconductor layer 11, particularly from the side surface, so that color unevenness can be eliminated. In this case, the width of the stepped portion 12 is preferably larger than half of the average particle diameter of the phosphor particles 14 and 14c.

  The inverted mesa shapes of Examples 4 and 5 can be formed, for example, by making the etching time longer than usual in the etching process shown in FIG. In the case of Example 4, the etching time is further increased compared to Example 5.

  Further, the light emitting device having the inverted mesa shape of Example 4 or 5 may be combined with the rough bottom surface structure of the step portion 12 of Example 2 or 3.

  FIGS. 12A to 12C show another method for forming the wavelength conversion layer 13 as Example 6 of the present invention. In the light emitting device of Example 6, a binder layer 41 is applied to the surface of the semiconductor layer 11 and the stepped portion 12 as shown in FIG. The binder layer 41 has a high viscosity, for example, 300 mPa · s or more. The binder layer 41 is formed using a spray method, an inkjet method, or a printing method. As shown in FIG. 12B, the first binder 35 including the phosphor particles 14 is applied on the binder layer 41, and after the binder layer 41 and the first binder 35 are cured, the binder layer 41 is shown in FIG. Thus, the 2nd binder 36 is apply | coated so that the space | gap between the fluorescent substance particles 14 of the hardened 1st binder 35 may be filled up.

  In Example 6, FIGS. 12B and 12C are the same as the first binder application process and the second binder application process described above, but the binder layer 41 having a high viscosity is formed on the surface of the semiconductor layer 11 and the step portion. 12, the phosphor particles 14 are likely to stay at the step portions 12 and the end portions of the semiconductor layer 11, and the film thickness uniformity of the wavelength conversion layer 13 can be improved. Further, since the binder layer 41 covers the entire surface of the semiconductor layer 11 and completely fills the gaps between the phosphor particles 14 together with the first binder 35, the light extraction can be improved.

  FIG. 13 shows a sectional view of a light emitting device as Example 7 of the present invention. In the light emitting device of Example 7, a recess 45 is formed along the side direction of the substrate 10 on the substrate 10 forming the bottom surface of the stepped portion 12. The recess 45 has a maximum width that is not less than ½ of the particle diameter of the phosphor particles 14 and not more than the particle diameter of the phosphor particles 14, and a maximum depth that is less than ½ of the particle diameter of the phosphor particles 14. . The cross-sectional shape of the recess 45 is triangular as shown in FIG. By forming the recess 45 on the bottom surface of the stepped portion 12 in this manner, the possibility that the phosphor particles 14 remain in the recess 45 due to the spraying of the first binder 35 becomes higher. When the phosphor particles 14 stay in the recess 45, the phosphor particles 14 stay on the bank and the phosphor particles easily stay on the edge of the semiconductor layer 11. Therefore, the thickness of the wavelength conversion layer is set to the semiconductor layer 11. It can be made uniform over the part corresponding to the edge part. The depth of the stepped portion 12 including the depth of the recess 45 is set so that the phosphor particles 14 disposed in the recess 45 protrude from the surface of the semiconductor layer 11. The depth of the stepped portion 12 including the depth of the concave portion 45, that is, the substantially equal distance from the apex portion of the triangular cross section of the concave portion 45 to the upper surface of the semiconductor layer 11 is smaller than ½ of the particle size of the phosphor particles 14. It is preferable.

  14 (a) to 14 (d) show a method for forming the recess 45 of the seventh embodiment of the present invention. FIG. 14A shows a state in which the etching process is completed through the epilayer bonding process and the resist forming process shown in FIGS. 6A and 6B, respectively. That is, in this etching process, only the portion of the epitaxial layer 32 not masked with the resist 33 is etched, and the substrate material 31 is not etched. The epitaxial layer 32 is divided into device units corresponding to the semiconductor layer 11 by etching.

  After the etching process of FIG. 14A, as shown in FIGS. 14B to 14D, a resist formation process, an etching process, and a cutting process are performed in that order.

  In the resist formation step of FIG. 14B, the resist 51 is formed except for the position where the recess 45 is formed on the substrate material 31. In the etching process of FIG. 14C, for example, the substrate material 31 in a portion not masked with the resist 51 is etched by using a wet etching method. The etching first removes the above-mentioned fusion-bonded metal adhesive layer (not shown) on the substrate material 31, thereby forming a recess 45 in the substrate material 31. The resist 33 is removed after the etching.

  In the cutting step, the substrate material 31 is divided into device units. The cutting position is between adjacent recesses 45 as indicated by a broken line in FIG. As a result of this cutting, the stepped portion 12 having the substrate 10, the semiconductor layer 11, and the recess 45 is obtained in units of devices. After that, the first and second binder application steps shown in FIGS. 6E and 6F are executed for each apparatus.

  FIG. 15 shows a sectional view of a light emitting device as an eighth embodiment of the present invention. In the light emitting device of Example 8, a recess 46 is formed along the side direction of the substrate 10 at the end on the substrate 10 forming the bottom surface of the stepped portion 12. The cross-sectional shape of the recess 46 is curved as shown in FIG. In the eighth embodiment in which the curved concave portion 46 is formed, the same functions and effects can be achieved as in the seventh embodiment in which the triangular concave portion 45 is formed.

  Also in this embodiment, the depth of the stepped portion 12 including the depth of the recess 46 is set so that the phosphor particles 14 arranged in the recess 46 protrude from the surface of the semiconductor layer 11. The recess 46 has a maximum width that is 1/2 or more of the particle diameter of the phosphor particles 14 and less than or equal to the particle diameter of the phosphor particles 14, and a maximum depth that is 1/4 or less of the particle diameter of the phosphor particles 14. The depth of the step portion 12 is preferably smaller than ½ of the particle size of the phosphor particles 14.

  FIG. 16 shows the appearance of the surface side of the semiconductor layer 11 before the wavelength conversion layer 13 is formed as Example 9 of the present invention. In the light emitting device of Example 9, a plurality of circular dimple holes 47 are arranged along the side direction of the substrate 10 at the end on the substrate 10 that forms the bottom surface of the stepped portion 12. The arrangement interval of the dimple holes 47 may be equal or random. The diameter of the dimple hole 47 is smaller than half the volume average particle diameter of the phosphor particles 14. By forming the plurality of dimple holes 47 at the end portion on the substrate 10 in this manner, the possibility that the phosphor particles 14 are fitted into the dimple holes 47 due to the spray from the spray of the first binder 35 is increased. . When the phosphor particles 14 are fitted into the dimple holes 47, the phosphor particles 14 that are fitted become banks, and the phosphor particles 14 are likely to stay on the edge of the semiconductor layer 11, so that the layer of the wavelength conversion layer 13 The thickness can be made uniform over a portion corresponding to the end portion of the semiconductor layer 11.

  In each of the above embodiments, the depth of the step portion 12 reaches from the surface of the semiconductor layer 11 to the inside of the substrate 10, but the step portion 12 has a depth to the surface of the substrate 10, that is, the depth of the semiconductor layer 11. It may have a depth corresponding to the thickness.

  In each of the above embodiments, the semiconductor layer 11 is a metal bonding type light emitting element, but the present invention can also be applied to other face-up type light emitting elements. Further, the semiconductor layer 11 is not limited to the GaN-based light emitting diode shown in the embodiment, and other light emitting elements of AlGaAs or ZnO can be used.

DESCRIPTION OF SYMBOLS 10 Substrate 11 Semiconductor layer 12 Step part 13 Wavelength conversion layer 14, 14c Phosphor particle 31 Substrate material 32 Epitaxial layer 47 Dimple hole

Claims (7)

A light emitting device comprising: a substrate; a semiconductor layer disposed on the substrate and including a light emitting layer; and a wavelength conversion layer including a plurality of phosphor particles disposed on the semiconductor layer,
The semiconductor layer has a step portion extending to at least the substrate at the end of the semiconductor layer, and the width of the step portion from the side surface position of the semiconductor layer to the side of the substrate is larger than half of the average particle diameter of the phosphor particles, the depth of the stepped portion is an average smaller than the diameter Kuna' of the phosphor particles,
The light emitting device according to claim 1, wherein a surface of the substrate that forms a bottom surface of the stepped portion is roughened . A light emitting device comprising: a substrate; a semiconductor layer disposed on the substrate and including a light emitting layer; and a wavelength conversion layer including a plurality of phosphor particles disposed on the semiconductor layer,
The semiconductor layer has a step portion extending to at least the substrate at the end of the semiconductor layer, and the width of the step portion from the side surface position of the semiconductor layer to the side of the substrate is larger than half of the average particle diameter of the phosphor particles, The depth of the stepped portion is smaller than the average particle diameter of the phosphor particles,
The light emitting device according to claim 1, wherein at least a side surface of the substrate facing the step portion has an inverted mesa shape . A light emitting device comprising: a substrate; a semiconductor layer disposed on the substrate and including a light emitting layer; and a wavelength conversion layer including a plurality of phosphor particles disposed on the semiconductor layer,
The semiconductor layer has a step portion extending to at least the substrate at the end of the semiconductor layer, and the width of the step portion from the side surface position of the semiconductor layer to the side of the substrate is larger than half of the average particle diameter of the phosphor particles, The depth of the stepped portion is smaller than the average particle diameter of the phosphor particles,
The step portion has a concave portion along a side direction of the substrate on the substrate forming a bottom surface . A light emitting device comprising: a substrate; a semiconductor layer disposed on the substrate and including a light emitting layer; and a wavelength conversion layer including a plurality of phosphor particles disposed on the semiconductor layer,
The semiconductor layer has a step portion extending to at least the substrate at the end of the semiconductor layer, and the width of the step portion from the side surface position of the semiconductor layer to the side of the substrate is larger than half of the average particle diameter of the phosphor particles, The depth of the stepped portion is smaller than the average particle diameter of the phosphor particles,
The step portion includes a plurality of dimple holes arranged along a side direction of the substrate on the substrate forming a bottom surface . The width of the stepped portion is not more than twice the average particle size of the phosphor particles, the depth of the stepped portion is not less than 1/5 of the average particle size of the phosphor particles, and The light-emitting device according to claim 1 , wherein the light-emitting device has an average particle size of 8/15 or less. At least one of the phosphor particles on the substrate in the step portion is disposed, phosphor particles, any one of claims 1 to 5 is disposed so as to protrude from the upper surface position of the semiconductor layer Light-emitting device. A step of providing a light emitting element including a substrate and a semiconductor layer including a light emitting layer formed on the substrate, and having a stepped portion reaching at least the substrate at an end of the semiconductor layer;
Spraying a coating liquid containing phosphor particles from above the light emitting element to form a wavelength conversion layer on the upper surface of the light emitting element, and
The width of the stepped portion from the side surface position of the semiconductor layer to the side of the substrate is formed to be larger than half of the average particle size of the phosphor particles, and the depth of the stepped portion is larger than the average particle size of the phosphor particles. Formed small ,
A method of manufacturing a light emitting device, wherein a surface of the substrate forming a bottom surface of the stepped portion is roughened .

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