JP2017076673A - Method for manufacturing light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a light-emitting device which has a plurality of light-emitting elements, and an uninterrupted phosphor layer covering upper faces of the plurality of light-emitting elements, and which is small in color unevenness.SOLUTION: A method for manufacturing a light-emitting device 1 is provided according to an embodiment of the present invention. The method comprises the steps of: preparing a pair of face-down type light-emitting elements 11 and 12 mounted on a substrate 10; embedding a resin 13 in a region between the light-emitting elements 11 and 12 to a position higher than upper faces of the light-emitting elements 11 and 12; polishing the upper face of the resin 13 to make its height equal to the upper faces of the light-emitting elements 11 and 12, and smoothing their upper faces after curing the resin 13; and forming an uninterrupted phosphor layer 14 to cover the upper faces of the light-emitting elements 11 and 12, and the resin 13 after the polishing step.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for manufacturing a light emitting device.

  As a conventional light-emitting device, light emission having a first sealing material that does not contain a phosphor that directly seals a light-emitting element, and a second sealing material that contains a phosphor that covers the first sealing material An apparatus is known (see, for example, Patent Document 1).

  Further, conventionally, a plate-like light transmitting member made of a phosphor single crystal or a sintered body, a sintered body of a phosphor and an inorganic substance (binding material), and the like is installed on a flip chip mounted LED chip, A light-emitting element in which the periphery of an LED chip and a light transmission member is covered with a sealing resin made of a resin containing a light-reflective material is known (for example, see Patent Document 2).

  Conventionally, a white LED chip is known in which a thin layer of conversion material is attached to a chip during the manufacturing process (see, for example, Patent Document 3).

JP 2010-62286 A International Publication No. 2009/069671 JP 2009-60113 A

  One of the objects of the present invention is to provide a method for manufacturing a light-emitting device having a plurality of light-emitting elements and a continuous phosphor layer covering the top surfaces of the plurality of light-emitting elements and having less color unevenness. is there.

  In order to achieve the above object, one embodiment of the present invention provides a method for manufacturing a light-emitting device according to any one of [1] to [4] below.

[1] A step of preparing two face-down light emitting elements mounted on a substrate, and a resin is embedded in a region between the two light emitting elements to a position higher than the upper surface of the two light emitting elements. A step of polishing the upper surface of the resin after the resin is cured, aligning the height with the two light emitting elements and smoothing the upper surface, and after the polishing process, Forming a continuous phosphor layer covering the upper surface of the two light emitting elements and the resin.

[2] The method for manufacturing a light-emitting device according to [1], wherein the phosphor layer is formed by applying a resin in which phosphor particles are dispersed to the two light-emitting elements and the upper surface of the resin and curing the resin. .

[3] The method for manufacturing a light-emitting device according to [1], wherein the phosphor layer is formed by placing a plate-like phosphor-containing member or phosphor on the two light-emitting elements and the resin.

[4] The method for manufacturing a light-emitting device according to any one of [1] to [3], wherein the resin is a transparent or white resin.

  ADVANTAGE OF THE INVENTION According to this invention, it can provide the manufacturing method of a light-emitting device which is a light-emitting device which has a several fluorescent element and the continuous fluorescent substance layer which covers the upper surface of a several light-emitting element, and there is little color unevenness.

FIG. 1 is a vertical cross-sectional view of the light emitting device according to the first embodiment. 2A and 2B are vertical sectional views of a light emitting device as a comparative example, respectively. 3A to 3D are vertical sectional views showing an example of a manufacturing process of the light emitting device according to the first embodiment. FIG. 4 is a vertical sectional view showing a modification of the resin forming method. FIG. 5 is a vertical cross-sectional view of the light emitting device according to the second embodiment. 6A to 6D are vertical sectional views showing an example of a manufacturing process of the light emitting device according to the second embodiment. FIG. 7 is a vertical sectional view of the light emitting device according to the third embodiment. 8A to 8D are vertical sectional views showing an example of a manufacturing process of the light emitting device according to the third embodiment.

[First Embodiment]
(Configuration of light emitting device)
FIG. 1 is a vertical cross-sectional view of a light emitting device 1 according to the first embodiment.

  The light-emitting device 1 includes a substrate 10, a face-down light-emitting element 11 and a light-emitting element 12 mounted on the substrate 10, a resin 13 embedded in a region between the light-emitting element 11 and the light-emitting element 12, and light emission And a continuous phosphor layer 14 covering the top surfaces of the elements 11 and 12 and the resin 13.

The substrate 10 is, for example, a ceramic substrate such as an Al ₂ O ₃ substrate or an AlN substrate, a metal substrate such as an Al substrate or a Cu substrate whose surface is covered with an insulating film, or a glass epoxy substrate. In addition, the substrate 10 has a wiring 15 serving as a power supply path to the light emitting element 11a and the light emitting element 11b on the surface.

  The light emitting elements 11 and 12 are light emitting elements having chip substrates 11a and 12a and crystal layers 11b and 12b including a light emitting layer, respectively, and are, for example, LED chips or laser diode chips. The light emitting elements 11 and 12 are face-down type light emitting elements in which the crystal layers 11b and 12b face downward. In the example shown in FIG. 1, the light emitting elements 11 and 12 are flip chip type light emitting elements.

  One of the electrodes 11c and 11d of the light emitting element 11 is an n-side electrode, and the other is a p-side electrode. Similarly, one of the electrodes 12c and 12d of the light emitting element 12 is an n-side electrode and the other is a p-side electrode. The electrodes 11c, 11d, 12c, and 12d are connected to the wiring 15 through a conductive member 16 such as a solder ball.

  The resin 13 is a thermosetting resin such as a transparent or white silicone resin or epoxy resin. When the resin 13 is white, a thermosetting resin containing a white pigment is used. The upper surface of the resin 13 is smoothed by a polishing process and is located at the same height as the upper surfaces of the light emitting elements 11 and 12 (the upper surfaces of the chip substrates 11a and 12a).

  For example, when the resin 13 is transparent, the light emitted from the light emitting elements 11 and 12 is hardly disturbed, so that high light emission efficiency is obtained. Further, when the resin 13 is white, the light emitted from the light emitting elements 11 and 12 to the side is reflected, so that the directivity of the light emitting device 1 can be improved.

  The phosphor layer 14 includes, for example, a transparent resin such as a silicone resin or an epoxy resin, and phosphor particles 17 dispersed in the transparent resin. The fluorescent color of the phosphor particles 17 is not particularly limited. For example, examples of yellow phosphor particles include BOS (barium orthosilicate) phosphors and YAG (yttrium aluminum garnet) phosphor particles. Used. For example, when the emission color of the light emitting elements 11 and 12 is blue and the fluorescent color of the phosphor particles 17 is yellow, the emission color of the light emitting device 1 is white.

  The phosphor layer 14 covers at least the upper surfaces of the light emitting elements 11 and 12 and the resin 13. Further, as shown in FIG. 1, the side surface of the light emitting element 11 that does not face the light emitting element 12 and the side surface of the light emitting element 12 that does not face the light emitting element 11 can also be covered. preferable.

  Since the upper surface of the resin 13 is smoothed and has the same height as the upper surfaces of the light emitting elements 11 and 12, the flatness and thickness uniformity of the phosphor layer 14 are high. For this reason, the optical path difference in the fluorescent substance layer 14 of the light emitted from the light emitting elements 11 and 12 can be reduced, and the color unevenness of the light emitting device 1 can be reduced.

  2A and 2B are vertical sectional views of a light emitting device 5 and a light emitting device 6 as comparative examples, respectively.

  The light emitting device 5 includes a resin 51 that has a convex upper surface and is not flat, instead of the resin 13 of the light emitting device 1. For this reason, as shown in FIG. 2A, the phosphor layer 14 on the resin 51 is also curved in a convex shape, and the optical path (arrow) of the light emitted from the light emitting elements 11 and 12 in this curved portion. Is longer than the case of being flat. For this reason, the color unevenness of the light emitting device 5 is larger than the color unevenness of the light emitting device 1.

  The light emitting device 6 includes a resin 61 that is not flat on the upper surface and is concavely curved instead of the resin 13 of the light emitting device 1. For this reason, as shown in FIG. 2B, the phosphor layer 14 on the resin 61 is also curved in a concave shape, and the optical path of light emitted from the light emitting elements 11 and 12 in this curved portion (indicated by arrows). (Exemplified) is shorter than the flat case. For this reason, the color unevenness of the light emitting device 6 is larger than the color unevenness of the light emitting device 1.

(Method for manufacturing light emitting device)
Below, an example of the manufacturing method of the light-emitting device 1 is demonstrated concretely.

  3A to 3D are vertical sectional views showing an example of a manufacturing process of the light emitting device 1 according to the first embodiment.

  First, as shown in FIG. 3A, face-down light emitting elements 11 and 12 mounted on a substrate 10 are prepared.

  Next, as shown in FIG. 3B, in a region between the light emitting element 11 and the light emitting element 12, a position higher than the upper surfaces of the light emitting element 11 and the light emitting element 12 (the upper surfaces of the chip substrates 11a and 12a). The resin 13 is embedded by dropping using a dispenser.

  Next, as shown in FIG. 3C, the upper surface of the resin 13 is subjected to a polishing process such as CMP (Chemical Mechanical Polishing), and the height thereof is aligned with the upper surfaces of the light-emitting elements 11 and 12. Is smoothed. At this time, the light-emitting element 11 and the light-emitting element 12 are face-down light-emitting elements, and the upper surfaces of the chip substrates 11a and 12a function as stoppers. Therefore, the light-emitting element 11 and the light-emitting element 12 are damaged in the polishing process of the resin 13. I will not receive it.

  Here, the polishing treatment is required to be performed after the resin 13 is cured by heat treatment or the like. This is because if the polishing process is performed before curing, the resin 13 contracts after the polishing process, and the height of the upper surface may be lower than the upper surfaces of the light emitting element 11 and the light emitting element 12.

  Next, as shown in FIG. 3 (d), a resin containing phosphor particles 17 is applied so as to cover the upper surfaces of the light emitting elements 11, 12 and the resin 13 by dropping using a dispenser, printing by screen printing, or the like. Apply and cure. Thus, a continuous phosphor layer 14 that covers the top surfaces of the light emitting elements 11 and 12 and the resin 13 is formed.

  FIG. 4 is a vertical sectional view showing a modification of the method for forming the resin 13. The resin 13 is not formed only in the region between the light emitting element 11 and the light emitting element 12 as shown in FIG. 3B, but between the light emitting element 11 and the light emitting element 12 as shown in FIG. The resin 13 may be formed so as to fill the region and further cover the upper surfaces of the light emitting element 11 and the light emitting element 12. Thereafter, the upper surface of the resin 13 is subjected to polishing treatment, and the resin 13 around the light emitting element 11 and the light emitting element 12 is removed, whereby the resin 13 having the form shown in FIG. 3C can be obtained. The surrounding resin 13 may not be removed. When the resin 13 is a white resin, the directivity can be improved by leaving the surrounding resin 13 (the same form as the resin 21 of the second embodiment described later).

[Second Embodiment]
The second embodiment is different from the first embodiment in the form of the phosphor layer. Note that the description of the same points as in the first embodiment will be omitted or simplified.

(Configuration of light emitting device)
FIG. 5 is a vertical sectional view of the light emitting device 2 according to the second embodiment.

  The light-emitting device 2 includes a substrate 10, a face-down light-emitting element 11 and a light-emitting element 12 mounted on the substrate 10, a resin 21 embedded in a region between the light-emitting element 11 and the light-emitting element 12, and light emission And a continuous phosphor layer 22 covering the top surfaces of the elements 11 and 12 and the resin 21.

  The resin 21 is a thermosetting resin such as a transparent or white silicone resin or epoxy resin. When the resin 21 is white, a thermosetting resin containing a white pigment is used. The upper surface of the resin 21 is smoothed by a polishing process, and is positioned at the same height as the upper surfaces of the light emitting elements 11 and 12 (the upper surfaces of the chip substrates 11a and 12a).

  The phosphor layer 22 is a plate-like phosphor-containing member or phosphor, for example, a transparent member such as a plate-like resin in which phosphor particles are dispersed, a plate-like phosphor sintered body, and a plate-like single crystal fluorescence. Consists of the body. The fluorescent color of the phosphor contained in the phosphor layer 22 or constituting the phosphor layer 22 is not particularly limited.

  Since the phosphor layer 22 is a plate-like member, the shape does not change even if the resin 21 is not formed. However, since air contains elements that corrode electrodes such as halogen and sulfur, it is not preferable that the region between the light emitting element 11 and the light emitting element 12 is hollow. Therefore, by forming the resin 21 in a region between the light emitting element 11 and the light emitting element 12, the light emitting elements 11 and 12 can be protected.

  In addition, when the region between the light emitting element 11 and the light emitting element 12 is hollow, the light emitting elements 11 and 12 have a large refractive index (for example, 2.4) and air refractive index (1.0). Reflection is likely to occur at the interface between 12 and this hollow region. Therefore, by forming a transparent resin 21 having a refractive index closer to that of the light emitting elements 11 and 12 than that of air in a region between the light emitting elements 11 and 12, light emitted from the light emitting elements 11 and 12 to the side. Can be taken out easily.

  Further, when the resin 21 is white, the light emitted from the light emitting elements 11 and 12 to the side is reflected, so that the directivity of the light emitting device 1 can be improved.

  In order to enhance the above-described effects (protection, reflection reduction, and directivity improvement), the resin 21 not only includes the region between the light emitting element 11 and the light emitting element 12 but also the light emitting element 11 as shown in FIG. It is preferable that the light emitting element 11 is also formed around the light emitting element 12 so as to cover all side surfaces of the light emitting element 12.

  In addition, since the upper surface of the resin 21 is smoothed and has the same height as the upper surfaces of the light emitting elements 11 and 12, the inclination of the phosphor layer 22 due to the unevenness of the resin 21 is suppressed. For this reason, the optical path difference in the fluorescent substance layer 22 of the light emitted from the light emitting elements 11 and 12 can be reduced, and the color unevenness of the light emitting device 2 can be reduced.

  For example, when the upper surface of the resin 21 is higher than the upper surfaces of the light emitting elements 11 and 12, the phosphor layer 22 is inclined and the optical path difference is increased, so that the color unevenness is increased. On the other hand, when the upper surface of the resin 21 is at a position lower than the upper surfaces of the light emitting elements 11 and 12, the effects (protection, reflection reduction, and improvement in directivity) of the resin 21 are reduced.

(Method for manufacturing light emitting device)
Below, an example of the manufacturing method of the light-emitting device 2 is demonstrated concretely.

  6A to 6D are vertical sectional views showing an example of a manufacturing process of the light emitting device 2 according to the second embodiment.

  First, as shown in FIG. 6A, face-down light emitting elements 11 and 12 mounted on a substrate 10 are prepared.

  Next, as illustrated in FIG. 6B, a resin 21 is formed so as to fill a region between the light emitting element 11 and the light emitting element 12 and further cover the upper surfaces of the light emitting element 11 and the light emitting element 12. At this time, as shown in FIG. 6B, it is preferable that the resin 21 also covers the periphery of the light emitting element 11 and the light emitting element 12.

  Next, as shown in FIG. 6C, after the resin 21 is cured by heat treatment or the like, the upper surface of the resin 21 is subjected to polishing treatment such as CMP, and the height thereof is set to the upper surface of the light emitting element 11 and the light emitting element 12. And the top surface is smoothed. At this time, the light-emitting element 11 and the light-emitting element 12 are face-down light-emitting elements, and the upper surfaces of the chip substrates 11a and 12a function as stoppers. Therefore, the light-emitting element 11 and the light-emitting element 12 are damaged in the polishing process of the resin 21. I will not receive it.

  Next, as shown in FIG. 6D, the phosphor layer 22 is placed on the light emitting element 11 and the light emitting element 12. It is preferable that the phosphor layer 22 and the upper surfaces of the light emitting element 11 and the light emitting element 12 (the upper surfaces of the chip substrates 11a and 12a) are bonded by a thermosetting resin such as a silicone resin or an epoxy resin.

[Third Embodiment]
The third embodiment is different from the second embodiment in the form of resin. Note that the description of the same points as in the second embodiment will be omitted or simplified.

(Configuration of light emitting device)
FIG. 7 is a vertical sectional view of the light emitting device 3 according to the third embodiment.

  The light-emitting device 3 includes a substrate 10, face-down light-emitting elements 11 and 12 mounted on the substrate 10, a resin 31 embedded in a region between the light-emitting elements 11 and 12, and light emission The continuous phosphor layer 22 covering the top surfaces of the elements 11, 12 and the resin 31, the side surface of the light emitting element 11 that does not face the light emitting element 12, and the light emitting element 11 of the side surface of the light emitting element 12 And a resin 32 that covers the side surfaces that are not facing each other.

  The resin 31 is a thermosetting resin such as a transparent silicone resin or epoxy resin. The resin 32 is a thermosetting resin such as a white silicone resin or an epoxy resin. In the light emitting device 3, the directivity can be improved by the white resin 32, and the light extraction efficiency can be improved by suppressing the light absorption by the transparent resin 31.

  Further, the upper surfaces of the resin 31 and the resin 32 are smoothed by a polishing process, and are positioned at the same height as the upper surfaces of the light emitting elements 11 and 12 (the upper surfaces of the chip substrates 11a and 12a).

  The phosphor layer 22 is a plate-like phosphor-containing member or phosphor, for example, a transparent member such as a plate-like resin in which phosphor particles are dispersed, a plate-like phosphor sintered body, and a plate-like single crystal fluorescence. Consists of the body. The fluorescent color of the phosphor contained in the phosphor layer 22 or constituting the phosphor layer 22 is not particularly limited.

  Since the upper surfaces of the resin 31 and the resin 32 are smoothed and have the same height as the upper surfaces of the light-emitting elements 11 and 12, color unevenness caused by the inclination of the phosphor layer 22 and the effects (protection, Reduction in reflection and improvement in directivity is suppressed.

(Method for manufacturing light emitting device)
Below, an example of the manufacturing method of the light-emitting device 3 is demonstrated concretely.

  8A to 8D are vertical sectional views showing an example of the manufacturing process of the light emitting device 3 according to the third embodiment.

  First, as shown in FIG. 8A, a process similar to the process shown in FIGS. 3A to 3B of the first embodiment is performed, and then between the light emitting element 11 and the light emitting element 12 is performed. In the region, the resin 31 is embedded up to a position higher than the upper surfaces of the light emitting elements 11 and 12 (the upper surfaces of the chip substrates 11a and 12a).

  Next, as shown in FIG. 8B, the upper surfaces of the light emitting elements 11, 12 and the resin 31, the side surface of the light emitting element 11 that does not face the light emitting element 12, and the side surface of the light emitting element 12. A resin 32 is applied and cured so as to cover a side surface not facing the light emitting element 11.

  Next, as shown in FIG. 8C, the upper surfaces of the resin 32 and the resin 31 are subjected to a polishing process such as CMP, and their heights are aligned with the upper surfaces of the light-emitting element 11 and the light-emitting element 12. Smooth.

  Next, as shown in FIG. 8D, the phosphor layer 22 is placed on the light emitting element 11 and the light emitting element 12.

(Effect of embodiment)
According to the first to third embodiments, the optical path difference in the phosphor layer can be reduced, and the color unevenness of the light emitting device can be reduced.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention.

  For example, in the first to third embodiments, two light emitting elements are included in the light emitting device, but three or more light emitting elements may be included. In this case, there are a plurality of regions between the light emitting elements, and a resin whose upper surface is smoothed is formed in each of these regions.

  Moreover, said embodiment does not limit the invention which concerns on a claim. In addition, it should be noted that not all the combinations of features described in the embodiments are essential to the means for solving the problems of the invention.

1, 2, 3 Light emitting device 10 Substrate 11, 12 Light emitting element 13, 21, 31, 32 Resin 14, 22 Phosphor layer

Claims (4)

A step of preparing two face-down light emitting elements mounted on a substrate;
Embedding a resin in a region between the two light emitting elements to a position higher than the upper surface of the two light emitting elements;
After the resin is cured, a process of polishing the upper surface of the resin, aligning its height with the two light emitting elements, and smoothing the upper surface;
A step of forming a continuous phosphor layer covering the top surfaces of the two light emitting elements and the resin after the polishing treatment;
A method for manufacturing a light emitting device, comprising: The phosphor layer is formed by applying and curing a resin in which phosphor particles are dispersed on the top surfaces of the two light emitting elements and the resin.
The manufacturing method of the light-emitting device of Claim 1. The phosphor layer is formed by placing a plate-like phosphor-containing member or phosphor on the two light-emitting elements and the resin.
The manufacturing method of the light-emitting device of Claim 1. The resin is a transparent or white resin,
The manufacturing method of the light-emitting device of any one of Claims 1-3.

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