Light-emitting element and method for manufacturing the same

Abstract

To provide a light-emitting element and a method for manufacturing the light-emitting element capable of suppressing deterioration of a semiconductor light emitting element body.SOLUTION: A light-emitting element 1 includes a semiconductor light emitting element body 2, an inner covering portion 3 for flattening a surface of the semiconductor light emitting element body 2, and an outer covering portion 4 made of an inorganic material covering the inner covering portion 3. A manufacturing method of the light-emitting element 1 includes the steps of manufacturing the semiconductor light emitting element body 2, covering the surface of the semiconductor light emitting element body 2 with the inner coating portion 3 so as to planarize the surface of the semiconductor light emitting element body 2, and covering the inner covering portion 3 with the outer covering portion 4 made of an inorganic material.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a light-emitting element and a method for manufacturing the light-emitting element.

Background Art

[0002] Patent Document 1 discloses a semiconductor light-emitting element in which a semiconductor light-emitting element body including an n-type semiconductor layer, a light-emitting layer, a p-type semiconductor layer, an n-type contact electrode, and a p-type contact electrode is directly coated with an insulating layer made of silicon oxide (SiO 2 ).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the semiconductor light-emitting element described in Patent Document 1, the insulating layer constituting the outermost surface of the semiconductor light-emitting element directly covers the semiconductor light-emitting element body. Therefore, if cracks occur in the insulating layer starting from step portions and corner portions on the surface of the semiconductor light-emitting element body, moisture may reach the vicinity of the semiconductor light-emitting element body through the cracks, and the semiconductor light-emitting element body may deteriorate.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a light-emitting element and a method for manufacturing the light-emitting element that can suppress deterioration of the semiconductor light-emitting element body.

Means for Solving the Problems

[0006] In order to achieve the above object, the present invention provides a semiconductor light-emitting device including: a first semiconductor layer having a first conductivity type; a light-emitting layer formed on the first semiconductor layer; a second semiconductor layer formed on the light-emitting layer and having a second conductivity type opposite to the first conductivity type; a first contact electrode connected to the first semiconductor layer; a second contact electrode connected to the second semiconductor layer; an inner coating portion made of an organic polymer material for flattening the surface of the semiconductor light-emitting device body; an outer coating portion made of an inorganic material covering the inner coating portion; a first pad electrode connected to the first contact electrode; and a second pad electrode connected to the second contact electrode. The inner coating portion covers the surfaces of the first contact electrode, the light-emitting layer, the second semiconductor layer, and the second contact electrode. A contact hole is formed in the inner coating portion, penetrating the inner coating portion in the thickness direction thereof and having one end opening toward the first contact electrode. A hole inner conductor for electrically connecting the first contact electrode and the first pad electrode is disposed in the contact hole. The area of the cross section of the hole inner conductor orthogonal to the thickness direction is 5% or more and 95% or less of the area of the first contact electrode orthogonal to the thickness direction. Further, the upper surface of the inner coating portion is formed flush with the upper surface of the second contact electrode. To provide a light-emitting device.

[0007] Further, in order to achieve the above object, the present invention forms a first semiconductor layer having a first conductivity type, forms a light-emitting layer on the first semiconductor layer, forms a second semiconductor layer having a second conductivity type opposite to the first conductivity type on the light-emitting layer, connects a first contact electrode on the first semiconductor layer, connects a second contact electrode on the second semiconductor layer to manufacture a semiconductor light-emitting element body, a step of covering the surface of the semiconductor light-emitting element body with an inner covering portion made of an organic polymer material so as to flatten the surface of the semiconductor light-emitting element body, a step of forming a contact hole opening to the first contact electrode in the inner covering portion, a step of covering the inner covering portion with an outer covering portion made of an inorganic material, and a step of forming a hole inner conductor electrically connected to the first contact electrode in the contact hole by vapor deposition. In the step of covering the semiconductor light-emitting element body with the inner covering portion, the inner covering portion is formed by applying and curing the organic polymer material constituting the inner covering portion on the surface of the semiconductor light-emitting element body. In the step of covering the semiconductor light-emitting element body with the inner covering portion, the surfaces of the first contact electrode, the light-emitting layer, the second semiconductor layer, and the second contact electrode are covered with the inner covering portion, and the area of the cross section of the hole inner conductor orthogonal to the thickness direction of the inner covering portion is 5% or more and 95% or less of the area of the first contact electrode orthogonal to the thickness direction. Further, the upper surface of the inner coating portion is formed flush with the upper surface of the second contact electrode. Provided is a method for manufacturing a light-emitting element.

Effects of the Invention

[0008] According to the present invention, it is possible to provide a light-emitting element capable of suppressing deterioration of a semiconductor light-emitting element body and a method for manufacturing the light-emitting element.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0010] [Embodiment] Embodiments of the present invention will be described with reference to FIGS. 1 to 7. Note that the embodiments described below are shown as preferred specific examples for carrying out the present invention, and although there are parts that specifically exemplify various technically preferable technical matters, the technical scope of the present invention is not limited to this specific aspect.

[0011] (Light-emitting element 1) FIG. 1 is a plan view of the light-emitting element 1. FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1.

[0012] The light-emitting element 1 of this embodiment can be configured as, for example, a light-emitting diode (LED: Light Emitting Diode) or a semiconductor laser (LD: Laser Diode). In this embodiment, the light-emitting element 1 is configured as a deep-ultraviolet LED that emits deep-ultraviolet light, and can be used, for example, in fields such as sterilization (e.g., air purification, water purification, etc.), medical treatment (e.g., phototherapy, measurement / analysis, etc.), and UV curing. The light-emitting element 1 of this embodiment includes a semiconductor light-emitting element body 2 (hereinafter, sometimes simply referred to as "element body 2"), an inner coating portion 3, an outer coating portion 4, a first pad electrode 5, and a second pad electrode 6.

[0013] (Element body 2) As shown in FIG. 2, in the element body 2, a substrate 21, a buffer layer 22, a first semiconductor layer 23 having a first conductivity type, a light-emitting layer 24, and a second semiconductor layer 25 having a second conductivity type are laminated. In this embodiment, the first conductivity type is n-type, and the first semiconductor layer 23 is a layer made of an n-type semiconductor. Also, the second conductivity type is p-type, and the second semiconductor layer 25 is a layer made of a p-type semiconductor. Further, the element body 2 includes a first contact electrode 26 connected to the first semiconductor layer 23 and a second contact electrode 27 connected to the second semiconductor layer 25.

[0014] Hereinafter, the stacking direction of the plurality of semiconductor layers constituting the element body 2 is referred to as the vertical direction Z. One side in the vertical direction Z, on which each semiconductor layer is stacked with respect to the substrate 21, is defined as the upper side, and the opposite side is defined as the lower side. Note that the expressions "upper" and "lower" are for convenience and do not limit the posture of the light-emitting element 1 with respect to the vertical direction, for example, when the light-emitting element 1 is in use.

[0015] The substrate 21 is a substrate having a property of transmitting light (deep ultraviolet light in this embodiment) emitted from the light-emitting layer 24, and can be, for example, a sapphire (Al 2 O 3 ) substrate. Also, as the substrate 21, for example, an aluminum nitride (AlN) substrate or an aluminum gallium nitride (AlGaN) substrate may be used.

[0016] As the semiconductor constituting the buffer layer 22, the first semiconductor layer 23, the light-emitting layer 24, and the second semiconductor layer 25, for example, a ternary to quaternary group III nitride semiconductor represented by Al x Ga y In 1-x-y N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ x + y ≦ 1) can be used. Note that in deep ultraviolet LEDs, an indium-free Al z Ga 1-z N-based (0 ≦ z ≦ 1) is often used.

[0017] The buffer layer 22 is formed on the substrate 21. The buffer layer 22 is an undoped Al a Ga 1-aIt consists of N (0≦a≦1). As an example, the buffer layer 22 has an AlN layer made of aluminum nitride (i.e., a = 1) formed on the substrate 21 and an AlGaN layer made of undoped aluminum gallium nitride (i.e., 0 < a < 1) formed on the AlN layer. Note that it is not limited to this, and the buffer layer 22 can also be a single layer. Also, when the substrate 21 is an aluminum nitride substrate or an aluminum gallium nitride substrate, the buffer layer 22 does not necessarily have to be provided.

[0018] The first semiconductor layer 23 is formed on the buffer layer 22. The first semiconductor layer 23 consists of Al b Ga 1-b N (0≦b≦1). The first semiconductor layer 23 may have a single-layer structure or a multi-layer structure. In a cross-sectional view parallel to the vertical direction (e.g., Figure 2), the width of the first semiconductor layer 23 is smaller than the width of the buffer layer 22, and when viewed from above, the outer shape of the first semiconductor layer 23 is within the outer shape of the buffer layer.

[0019] The light-emitting layer 24 is formed on a part of the upper surface of the first semiconductor layer 23, and the second semiconductor layer 25 is formed on the light-emitting layer 24. Here, the second contact electrode 27 formed on the second semiconductor layer 25 is formed in a comb shape as shown in Figure 1, and the light-emitting layer 24 and the second semiconductor layer 25 are formed in a comb shape similar to the second contact electrode 27 at a position overlapping the second contact electrode 27 in the vertical direction Z. The shape of the second contact electrode 27 will be described later.

[0020] The light-emitting layer 24 is Al c Ga 1-cIt consists of N (0 ≤ c ≤ 1), and can be, for example, a single quantum well structure having one well layer or a multiple quantum well structure having a plurality of well layers. In the light-emitting layer 24, electrons supplied from the first semiconductor layer 23 and holes supplied from the second semiconductor layer 25 recombine and emit light. The light-emitting layer 24 is configured to have a bandgap of 3.4 eV or more in order to output deep ultraviolet light with a wavelength of 365 nm or less. Particularly in this embodiment, the light-emitting layer 24 is configured to be able to generate deep ultraviolet light with a central wavelength of 200 nm or more and 365 nm or less.

[0021] The second semiconductor layer 25 is formed on the light-emitting layer 24. The second semiconductor layer 25 is composed of Al d Ga 1-d N (0 ≤ d ≤ 1). The second semiconductor layer 25 may have a single-layer structure or a multiple-layer structure.

[0022] In this embodiment, the side surface 231 of the first semiconductor layer 23, the side surface 241 of the light-emitting layer 24, and the side surface 251 of the second semiconductor layer 25 are inclined so that the first semiconductor layer 23, the light-emitting layer 24, and the second semiconductor layer 25 become narrower as they face upward. That is, in the element body 2 of this embodiment, the first semiconductor layer 23, the light-emitting layer 24, and the second semiconductor layer 25 are formed to have a mesa structure.

[0023] A first contact electrode 26 is formed on the exposed upper surface 232 exposed from the light-emitting layer 24 on the upper surface of the first semiconductor layer 23, and a second contact electrode 27 is formed on the upper surface of the second semiconductor layer 25. The first contact electrode 26 makes an ohmic contact with the first semiconductor layer 23, and the second contact electrode 27 makes an ohmic contact with the second semiconductor layer 25.

[0024] As shown in FIG. 1, the first contact electrode 26 has a first base portion 261 extending in a direction orthogonal to the vertical direction Z, and first protrusions 262 protruding from a plurality of locations on the first base portion 261 toward the second contact electrode 27. The second contact electrode 27 has a second base portion 271 formed substantially parallel to the first base portion 261, and second protrusions 272 protruding from a plurality of locations on the second base portion 271 toward the first contact electrode 26. When viewed from above, a plurality of second protrusions 272 are inserted one by one between adjacent first protrusions 262, whereby the first contact electrode 26 and the second contact electrode 27 are engaged with each other. Hereinafter, the direction orthogonal to the vertical direction Z and in which each of the first base portion 261 and the second base portion 271 extends is referred to as the lateral direction X, and the direction orthogonal to both the vertical direction Z and the lateral direction X is referred to as the longitudinal direction Y. The longitudinal direction Y is the direction in which each of the first protrusion 262 and the second protrusion 272 extends.

[0025] Note that the element body 2 is not limited to the above-described configuration, and a general configuration of the element body 2 can be adopted.

[0026] (Inner coating portion 3) The inner coating portion 3 covers the surface of the element body 2 to fill and flatten the steps and corners present on the surface shape of the element body 2. The inner coating portion 3 can be composed of an organic polymer material having electrical insulation properties. In this embodiment, the inner coating portion 3 is made of a photoresist. As the photoresist, either a positive type or a negative type can be adopted.

[0027] In this embodiment, the inner covering portion 3 covers the upper surface of the first semiconductor layer 23 and the surfaces of the first contact electrode 26, the light-emitting layer 24, the second semiconductor layer 25, and the second contact electrode 27, respectively. In particular, the inner covering portion 3 covers the step formed between the upper surface of the first semiconductor layer 23 and the light-emitting layer 24 and the first contact electrode 26, the step formed between the second semiconductor layer 25 and the second contact electrode 27, and the corner portions that may be formed on each of the first contact electrode 26, the light-emitting layer 24, the second semiconductor layer 25, and the second contact electrode 27. And the outer surface 31 (i.e., the surface in contact with the outer covering portion 4) of the inner covering portion 3 is configured to be flatter than the inner surface 32 (i.e., the surface in contact with the first contact electrode 26, the light-emitting layer 24, the second semiconductor layer 25, and the second contact electrode 27) of the inner covering portion 3. The outer surface 31 of the inner covering portion 3 includes an upper surface 311 orthogonal to the vertical direction Z and a side surface 312 parallel to the vertical direction Z. The corner 313 between the upper surface 311 and the side surface 312 is formed in a curved surface shape with a rounded corner. Note that the side surface 312 of the outer surface 31 of the inner covering portion 3 may be inclined outward, for example, more toward the lower side.

[0028] Here, as shown in FIG. 2, when the length in the vertical direction Z between the upper surface 273 of the second contact electrode 27 and the lower surface 33 of the inner covering portion 3 is H, the thickness T1 of the inner covering portion 3 satisfies 0.8H ≦ T1 ≦ 1.2H. That is, the upper surface 311 of the inner covering portion 3 is formed substantially flush with the upper surface 273 of the second contact electrode 27. It is preferable that the upper surface 311 of the inner covering portion 3 is formed flush with the upper surface 273 of the second contact electrode 27. Here, even when the upper surface 311 of the inner covering portion 3 and the upper surface 273 of the second contact electrode 27 are designed to be flush, but the positions of the upper surface 311 of the inner covering portion 3 and the upper surface 273 of the second contact electrode 27 are slightly displaced due to manufacturing tolerances or the like, the upper surface 311 of the inner covering portion 3 and the upper surface 273 of the second contact electrode 27 are considered to be flush. And the upper surface 273 of the second contact electrode 27 is exposed from the inner covering portion 3 in order to achieve electrical connection with the second pad electrode 6.

[0029] In the inner covering portion 3, a plurality of contact holes 34 penetrating the inner covering portion 3 in the vertical direction Z are formed. The plurality of contact holes 34 are formed at positions overlapping the first contact electrode 26 in the vertical direction Z, and the lower ends thereof are open toward the first contact electrode 26. The plurality of contact holes 34 have the same shape as each other and are formed at equal intervals. As shown in FIG. 1, the plurality of contact holes 34 opening in the first base portion 261 of the first contact electrode 26 are provided at equal intervals in the lateral direction X, and the plurality of contact holes 34 opening in the first protruding portion 262 of the second contact electrode 27 are formed at equal intervals in the longitudinal direction Y. The equal intervals are not limited to strict equal intervals, and include, for example, substantially equal intervals such that the difference between the maximum value and the minimum value of the intervals between adjacent contact holes 34 is 10% or less of the maximum value.

[0030] As shown in FIG. 2, the contact hole 34 is formed to be long in the vertical direction Z. In this embodiment, the length of the contact hole 34 in the vertical direction Z (which is equal to the length L of the inner hole conductor 51 described later in this embodiment) is longer than the thickness T2 of the first contact electrode 26. The contact hole 34 is formed in a tapered shape (a frustum of a cone shape in this embodiment) in which the inner diameter becomes larger at the upper position.

[0031] In this embodiment, the inner covering portion 3 has a single-layer structure, but may have a multi-layer structure. Further, the inner covering portion 3 is made of a photoresist, but may be made of, for example, an organic material other than the photoresist.

[0032] (Outer covering portion 4) The outer covering portion 4 is formed above the buffer layer 22 and covers the inner covering portion 3. The outer covering portion 4 has electrical insulation and is made of an inorganic material that is difficult to pass moisture. In this embodiment, the outer covering portion 4 is made of silicon dioxide (SiO 2 )

[0033] The outer covering portion 4 covers at least the upper surface of the buffer layer 22, the side surface 231 of the first semiconductor layer 23, and the inner covering portion 3. In the outer covering portion 4, a first opening 41 having a first pad electrode 5 formed therein and a second opening 42 having a second pad electrode 6 formed therein are formed. The first opening 41 is formed at a position facing the first contact electrode 26 in the vertical direction Z, and the second opening 42 is formed at a position facing the second contact electrode 27 in the vertical direction Z.

[0034] In this embodiment, the outer covering portion 4 is composed of a single layer, but it may be configured to be composed of a plurality of layers.

[0035] (The first pad electrode 5 and the second pad electrode 6) The first pad electrode 5 is electrically connected to the first contact electrode 26, and the second pad electrode 6 is electrically connected to the second contact electrode 27. When viewed from above, the first pad electrode 5 is formed on the side of the first base portion 261 of the first contact electrode 26 rather than at the central position in the longitudinal direction Y of the light emitting element 1, and the second pad electrode 6 is formed in a region on the side of the second base portion 271 of the second contact electrode 27 rather than at the central position.

[0036] The first pad electrode 5 integrally includes a hole inner conductor 51 formed to be filled in the contact hole 34, a first embedded portion 52 embedded in the first opening 41 of the outer covering portion 4, and a first exposed portion 53 exposed upward from the outer covering portion 4.

[0037] The in-hole conductor 51 is filled in each contact hole 34. Therefore, the shape of the in-hole conductor 51 is equivalent to the inner region of the contact hole 34 in which the in-hole conductor 51 is disposed. The in-hole conductor 51 is formed to be long in the vertical direction Z. The length L of the in-hole conductor 51 in the vertical direction Z is preferably longer than the thickness T2 of the first contact electrode 26 and preferably more than three times the thickness T2 of the first contact electrode 26. Further, the in-hole conductor 51 is formed in a tapered shape (frustum shape in this embodiment) in which the cross-sectional area of the cross-section orthogonal to the vertical direction Z increases toward the upper side, similar to the shape of the inner region of the contact hole 34. The cross-sectional area of the in-hole conductor 51 orthogonal to the vertical direction Z is preferably less than 100% of the area of the first contact electrode 26 orthogonal to the vertical direction Z, and more preferably 5% or more and 95% or less of the area of the first contact electrode 26 orthogonal to the vertical direction Z. The area of the first contact electrode 26 is the area of the upper surface of the first contact electrode 26. Note that, when a plurality of in-hole conductors 51 are formed as in this embodiment, the cross-sectional area of the in-hole conductor 51 orthogonal to the vertical direction Z means the sum of the cross-sectional areas of all the in-hole conductors 51 orthogonal to the vertical direction Z. Further, when each in-hole conductor 51 is formed in a tapered shape as in this embodiment, at each position in the vertical direction Z, the cross-sectional area of the in-hole conductor 51 is preferably less than 100% of the area of the first contact electrode 26 orthogonal to the vertical direction Z, and more preferably 5% or more and 95% or less. The lower end portion of the in-hole conductor 51 is electrically connected to the first contact electrode 26.

[0038] The first embedded portion 52 is formed to be filled in the first opening 41, and its lower end portion is connected to the upper end portion of each in-hole conductor 51. Although not shown, the first embedded portion 52 is formed in a comb-shaped region that is below the first exposed portion 53 and faces the first contact electrode 26 in the vertical direction Z.

[0039] The first exposed portion 53 is formed such that its shape when viewed from above is a substantially rectangular shape that is long in the lateral direction X, and its lower end portion is connected to the first embedded portion 52.

[0040] The second pad electrode 6 integrally includes a second embedded portion 61 embedded in the second opening 42 of the outer covering portion 4 and a second exposed portion 62 exposed upward from the outer covering portion 4.

[0041] The second embedded portion 61 is formed to be filled in the second opening 42, and its lower end is connected to the upper surface 273 of the second contact electrode 27. Although not shown in the figure, the second embedded portion 61 is formed in a comb-shaped region that is a region below the second exposed portion 62 and faces the second contact electrode 27 in the vertical direction Z.

[0042] The second exposed portion 62 is formed such that its shape when viewed from above is a substantially rectangular shape that is long in the lateral direction X, and its lower end is connected to the second embedded portion 61. The first exposed portion 53 and the second exposed portion 62 are arranged side by side with a space therebetween in the vertical direction Y.

[0043] Examples in which each of the first pad electrode 5 and the second pad electrode 6 is constituted by a single member are shown, but they may also be constituted by connecting a plurality of members in the vertical direction Z or the like.

[0044] The first exposed portion 53 of the first pad electrode 5 and the second exposed portion 62 of the second pad electrode 6 are mounted on the electrodes of a submount (not shown in the figure), for example. For example, the light-emitting element 1 is flip-chip mounted on the electrodes of the submount via gold (Au) bumps or the like with the posture that the substrate 21 is located on the side opposite to the submount. In this case, the light emitted from the light-emitting element 1 is mainly taken out from the substrate 21 of the element main body 2 to the side opposite to the submount.

[0045] (Manufacturing method of the light-emitting element 1) Next, an example of the manufacturing method of the light-emitting element 1 of the present embodiment will be described. The manufacturing method of the light-emitting element 1 includes an element body formation step, a first coating step, an exposure and development step, a second coating step, a removal step, and a pad electrode formation step. FIG. 3 is a cross-sectional view of the element body 2 after the element body formation step. FIG. 4 is a cross-sectional view of the element body 2 and the organic polymer material 30 after the first coating step. FIG. 5 is a cross-sectional view of the element body 2 and the inner coating portion 3 after the exposure and development step. FIG. 6 is a cross-sectional view of the element body 2, the inner coating portion 3, and the outer coating portion 4 after the second coating step. FIG. 7 is a cross-sectional view of the element body 2, the inner coating portion 3, and the outer coating portion 4 after the removal step.

[0046] In the element body formation step, a buffer layer 22, a first semiconductor layer 23, a light-emitting layer 24, and a second semiconductor layer 25 are formed on a substrate 21 using a well-known epitaxial growth method such as Metal Organic Chemical Vapor Deposition (MOCVD), Molecular Beam Epitaxy (MBE), or Hydride Vapor Phase Epitaxy (HVPE). The manufacturing conditions such as the growth temperature, growth pressure, and growth time for epitaxially growing each layer can be general conditions according to the composition of each layer.

[0047] After forming the buffer layer 22, the first semiconductor layer 23, the light-emitting layer 24, and the second semiconductor layer 25 on the substrate 21, a mask (not shown) is formed at a predetermined position on the upper surface of the second semiconductor layer 25. Then, the second semiconductor layer 25 and the light-emitting layer 24 formed at a position that does not overlap the mask in the vertical direction Z are removed by etching. As a result, an exposed upper surface 232 exposed from the light-emitting layer 24 is formed on the first semiconductor layer 23. After forming the exposed upper surface 232, the mask is removed.

[0048] Next, a first contact electrode 26 is formed on the exposed upper surface 232 of the first semiconductor layer 23, and a second contact electrode 27 is formed on the second semiconductor layer 25. The first contact electrode 26 and the second contact electrode 27 can be formed by well-known methods such as an electron beam evaporation method or a sputtering method. A cross-sectional view of the element body 2 after the element body forming step is shown in FIG. 3.

[0049] Next, as shown in FIG. 4, a first coating step is performed. In the first coating step, a liquid organic polymer material 30 that constitutes the inner coating portion 3 is applied so as to cover the upper portion of the buffer layer 22 in the element body 2. As the coating method, various methods such as spray coating and spin coating can be adopted. In the first coating step, the upper surface 273 of the second contact electrode 27 is made to be exposed upward from the inner coating portion 3. In the state after the first coating step, the upper surface 273 of the second contact electrode 27 may be covered by the inner coating portion 3. In this case, however, the organic polymer material 30 formed above the second contact electrode 27 in the subsequent exposure and development steps is removed to expose the upper surface 273 of the second contact electrode 27.

[0050] Next, an exposure and development process is performed. In the exposure and development process, the organic polymer material 30 is exposed and developed to form the inner coating portion 3 into a predetermined shape. In the exposure and development process, portions of the organic polymer material 30 that are not located above the first semiconductor layer 23 and the portions that will become the contact holes 34 are removed. When the organic polymer material 30 is a negative-type photoresist, the portions of the organic polymer material 30 other than the portions to be removed in the exposure and development process are exposed from above and developed. As a result, the exposed portions of the organic polymer material 30 remain after development and become the inner coating portion 3. Due to the diffusion of light during exposure, the contact holes 34 after development are formed such that the inner diameter becomes smaller toward the lower side. When the organic polymer material 30 is a positive-type photoresist, the portions of the organic polymer material 30 to be removed in the exposure and development process are exposed from above and developed. As a result, the portions of the organic polymer material 30 other than the exposed portions remain after development and become the inner coating portion 3. During exposure, the portions of the organic polymer material 30 that will become the contact holes 34 are irradiated with light more strongly at the upper portions, so the contact holes 34 after development are formed such that the inner diameter becomes smaller toward the lower side. The state after the exposure and development process is shown in FIG. 5.

[0051] Next, as shown in FIG. 6, a second coating process is performed. In the second coating process, an outer coating portion 4 is formed in the upper region from the buffer layer 22 using a well-known technique such as chemical vapor deposition (CVD). The outer coating portion 4 is formed on the buffer layer 22, the surface of the first semiconductor layer 23, the surface of the inner coating portion 3, and the upper surface 273 of the second contact electrode 27 that are exposed in the state immediately before the second coating process (i.e., the state shown in FIG. 5).

[0052] Next, as shown in FIG. 7, a removal process is performed. In the removal process, the upper portion of the second contact electrode 27 in the outer coating portion 4 is removed to form a first opening 41, the portion formed in the contact hole 34 in the outer coating portion 4 is removed, and the portion that will become the second opening 42 above the inner coating portion 3 in the outer coating portion 4 is removed to form the second opening 42.

[0053] Next, a pad electrode forming step is performed. In the pad electrode forming step, although not shown in the drawings, a mask is formed at a location on the upper surface of the outer covering portion 4 other than the locations where the first pad electrode 5 and the second pad electrode 6 are formed. Then, the first pad electrode 5 and the second pad electrode 6 are formed by vapor deposition. At this time, the first pad electrode 5 and the second pad electrode 6 are deposited in order from the bottom on the contact hole 34, the first opening 41, the second opening 42, and the space formed in the mask (not shown), and as shown in FIG. 2, the first pad electrode 5 and the second pad electrode 6 are formed. As described above, the light-emitting element 1 of the present embodiment can be manufactured.

[0054] (Operations and Effects of the Embodiment) The light-emitting element 1 of the present embodiment includes an element main body 2, an inner covering portion 3 that planarizes the surface of the element main body 2, and an outer covering portion 4 made of an inorganic material that covers the inner covering portion 3. In this way, instead of directly covering the surface of the element main body 2 having steps and corners with the outer covering portion 4 made of an inorganic material that is relatively prone to cracking, the outer covering portion 4 covers the element main body 2 planarized by the inner covering portion 3, whereby the occurrence of cracks in the outer covering portion 4 can be suppressed. When cracks occur in the outer covering portion 4, for example, moisture may pass through the cracks, leading to deterioration of the element main body 2. According to the configuration of the present embodiment, the waterproof property of the light-emitting element 1 can be improved, and as a result, the deterioration of the element main body 2 can be suppressed.

[0055] Further, the inner covering portion 3 covers the surfaces of the first contact electrode 26, the light-emitting layer 24, the second semiconductor layer 25, and the second contact electrode 27. Since these are likely to form steps or corners, according to the configuration of the present embodiment, the occurrence of cracks in the outer covering portion 4 can be further suppressed.

[0056] In addition, the inner coating portion 3 is formed with a contact hole 34 that penetrates the inner coating portion 3 in the thickness direction of the inner coating portion 3 (i.e., the vertical direction Z), and one end of which opens toward the first contact electrode 26. And a hole inner conductor 51 that electrically connects the first contact electrode 26 and the first pad electrode 5 is disposed in the contact hole 34. Therefore, the first contact electrode 26 and the first pad electrode 5 can be electrically connected via the hole inner conductor 51 in the contact hole 34. Thereby, in order to draw out the first contact electrode 26 to the outside of the inner coating portion 3, it is not necessary to increase the thickness of the first contact electrode 26 and align the position of the upper surface of the first contact electrode 26 with the position of the upper surface 273 of the second contact electrode 27. Therefore, at least one of reduction in material cost, weight reduction, and reduction in manufacturing time of the first contact electrode 26 is realized.

[0057] In addition, the cross-sectional area of the hole inner conductor 51 orthogonal to the vertical direction Z is 5% or more and 95% or less of the area of the first contact electrode 26 orthogonal to the vertical direction Z. By setting the cross-sectional area of the hole inner conductor 51 orthogonal to the vertical direction Z to 95% or less of the area of the first contact electrode 26 orthogonal to the vertical direction Z, at least one of reduction in material cost, weight reduction, and reduction in manufacturing time of the hole inner conductor 51 can be realized. Also, by setting the cross-sectional area of the hole inner conductor 51 orthogonal to the vertical direction Z to 5% or more of the area of the first contact electrode 26 orthogonal to the vertical direction Z, it is possible to suppress the electrical resistivity of the hole inner conductor 51 from becoming excessively high.

[0058] In addition, when the length in the vertical direction Z between the upper surface 273 of the second contact electrode 27 and the lower surface 33 of the inner coating portion 3 is H, the thickness T1 of the inner coating portion 3 satisfies 0.8H ≦ T1 ≦ 1.2H. By setting the thickness T1 of the inner coating portion 3 to 0.8H or more, most of the first contact electrode 26, the light-emitting layer 24, the second semiconductor layer 25, and the second contact electrode 27 can be covered by the inner coating portion 3. Also, by setting the thickness T1 of the inner coating portion 3 to 1.2H or less, reduction in material cost and weight reduction of the inner coating portion 3 can be achieved.

[0059] Further, the in-hole conductor 51 has a larger cross-sectional area in a plane orthogonal to the vertical direction Z toward the side opposite to the first contact electrode 26 side (i.e., the upper side). That is, since the side of the in-hole conductor 51 connected to the first buried portion 52 of the first pad electrode 5 is larger, bending of the in-hole conductor 51 is suppressed.

[0060] Further, the length L of the in-hole conductor 51 in the vertical direction Z is longer than the thickness T2 of the first contact electrode 26 (i.e., the vertical dimension of the first contact electrode 26). Therefore, even if the first contact electrode 26 is not formed thick, electrical connection between the first contact electrode 26 and the first pad electrode 5 can be achieved, and it is easier to realize at least one of reduction in material cost, weight reduction, and reduction in manufacturing time of the first contact electrode 26.

[0061] Further, the inner coating portion 3 is made of a photoresist. Therefore, the contact hole 34 can be easily formed.

[0062] Further, the inner coating portion 3 is made of an organic polymer material. Since the organic polymer material is less likely to crack compared to inorganic materials and the like, it is possible to suppress the occurrence of cracks in the inner coating portion 3 starting from a step or a corner on the surface of the element body 2.

[0063] Further, in the step of covering the element body 2 with the inner coating portion 3 in the method for manufacturing the light-emitting element 1, the inner coating portion 3 is formed by applying and curing the organic polymer material 30 constituting the inner coating portion 3 on the surface of the element body 2. Thus, by forming the inner coating portion 3 by an application method, it is easy to flatten the surface of the element body 2 with the inner coating portion 3.

[0064] Further, the method for manufacturing the light-emitting element 1 includes a step of forming, by vapor deposition, an in-hole conductor 51 electrically connected to the first contact electrode 26 in the contact hole 34. Therefore, a configuration in which the first contact electrode 26 embedded in the inner coating portion 3 is electrically drawn out to the outside of the inner coating portion 3 can be easily realized by vapor deposition of the in-hole conductor 51 into the contact hole 34.

[0065] As described above, according to this embodiment, it is possible to provide a light-emitting element capable of suppressing deterioration of the element body and a method for manufacturing the light-emitting element.

[0066] (Summary of the Embodiment) Next, the technical idea grasped from the embodiments described above will be described by referring to the reference numerals and the like in the embodiments. However, each reference numeral and the like in the following description are not limited to the members and the like that specifically show the components in the claims in the embodiments.

[0067] [1] The first embodiment of the present invention is a light-emitting element (1) including a semiconductor light-emitting element body (2), an inner coating portion (3) that planarizes the surface of the semiconductor light-emitting element body (2), and an outer coating portion (4) made of an inorganic material that covers the inner coating portion (3). Thereby, deterioration of the semiconductor light-emitting element body can be suppressed.

[0068] [2] The second embodiment of the present invention is, in the first embodiment, the semiconductor light-emitting element body (2) includes a first semiconductor layer (23) having a first conductivity type, a light-emitting layer (24) formed on the first semiconductor layer (23), a second semiconductor layer (25) formed on the light-emitting layer (24) and having a second conductivity type opposite to the first conductivity type, a first contact electrode (26) connected on the first semiconductor layer (23), and a second contact electrode (27) connected on the second semiconductor layer (25), and the inner coating portion (3) covers the surfaces of the first contact electrode (26), the light-emitting layer (24), the second semiconductor layer (25), and the second contact electrode (27). Thereby, it is possible to suppress the occurrence of cracks in the outer coating portion.

[0069] [3] In the third embodiment of the present invention, in the second embodiment, a first pad electrode (5) connected on the first contact electrode (26) and a second pad electrode (6) connected on the second contact electrode (27) are further provided. A contact hole (34) is formed in the inner coating portion (3) that penetrates the inner coating portion (3) in the thickness direction (Z) of the inner coating portion (3) and has one end opening toward the first contact electrode (26). A hole inner conductor (51) that electrically connects the first contact electrode (26) and the first pad electrode (5) is disposed in the contact hole (34). Thereby, at least one of reduction of the material cost, weight reduction, and reduction of the manufacturing time of the first contact electrode is realized.

[0070] [4] In the fourth embodiment of the present invention, in the third embodiment, the area of the cross section of the hole inner conductor (51) orthogonal to the thickness direction (Z) is 5% or more and 95% or less of the area of the first contact electrode (26) orthogonal to the thickness direction (Z). Thereby, at least one of reduction of the material cost, weight reduction, and reduction of the manufacturing time of the hole inner conductor can be realized, and it is possible to suppress the electrical resistivity of the hole inner conductor from becoming excessively high.

[0071] [5] In the fifth embodiment of the present invention, in the third or fourth embodiment, when the length in the thickness direction (Z) between the upper surface (273) of the second contact electrode (27) and the lower surface of the inner coating portion (3) is H, the thickness T1 of the inner coating portion (3) satisfies 0.8H ≦ T1 ≦ 1.2H. Thereby, most of the first contact electrode, the light emitting layer, the second semiconductor layer, and the second contact electrode can be covered with the inner coating portion 3, and reduction of the material cost and weight reduction of the inner coating portion 3 can be achieved.

[0072] [6] In the sixth embodiment of the present invention, in any one of the third to fifth embodiments, the cross-sectional area of the inner conductor (51) in the hole orthogonal to the thickness direction (Z) increases toward the side opposite to the first contact electrode (26) side. Thereby, the inner conductor in the hole is suppressed from being broken.

[0073] [7] In the seventh embodiment of the present invention, in any one of the third to sixth embodiments, the length (L) of the inner conductor (51) in the thickness direction (Z) is longer than the thickness (T2) of the first contact electrode (26). Thereby, it is easier to achieve at least one of reduction of the material cost of the first contact electrode, weight reduction, and reduction of the manufacturing time.

[0074] [8] In the eighth embodiment of the present invention, in any one of the third to seventh embodiments, the inner coating portion (3) is made of a photoresist. Thereby, the contact hole can be easily formed.

[0075] [9] In the ninth embodiment of the present invention, in any one of the first to eighth embodiments, the inner coating portion (3) is made of an organic polymer material (30). Thereby, it is possible to suppress the occurrence of cracks in the inner coating portion.

[0076]

[10] A method for manufacturing a light-emitting element (1) includes a step of manufacturing a semiconductor light-emitting element body (2), a step of covering the surface of the semiconductor light-emitting element body (2) with an inner coating portion (3) so as to flatten the surface of the semiconductor light-emitting element body (2), and a step of covering the inner coating portion (3) with an outer coating portion (4) made of an inorganic material. Thereby, it becomes possible to manufacture a light-emitting element in which the deterioration of the semiconductor light-emitting element body is suppressed.

[0077]

[11] In the 11th embodiment of the present invention, in the 10th embodiment, the inner coating portion (3) is made of an organic polymer material (30). In the step of covering the semiconductor light-emitting element body (2) with the inner coating portion (3), the inner coating portion (3) is formed by applying the organic polymer material (30) constituting the inner coating portion (3) onto the surface of the semiconductor light-emitting element body (2) and curing it. Thereby, it is easy to flatten the surface of the semiconductor light-emitting element body by the inner coating portion.

[0078]

[12] In the 12th embodiment of the present invention, in the 11th embodiment, in the step of manufacturing the semiconductor light-emitting element body (2), a first semiconductor layer (23) having a first conductivity type is formed, a light-emitting layer (24) is formed on the first semiconductor layer (23), a second semiconductor layer (25) having a second conductivity type opposite to the first conductivity type is formed on the light-emitting layer (24), a first contact electrode (26) is connected on the first semiconductor layer (23), a second contact electrode (27) is connected on the second semiconductor layer (25). In the step of covering the surface of the semiconductor light-emitting element body (2) with the inner coating portion (3), the surfaces of the first contact electrode (26), the light-emitting layer (24), the second semiconductor layer (25), and the second contact electrode (27) are covered with the inner coating portion (3). Further, a contact hole (34) that opens to the first contact electrode (26) is formed in the inner coating portion (3), and a hole inner conductor (51) electrically connected to the first contact electrode (26) is formed in the contact hole (34) by vapor deposition. Thereby, a configuration for electrically drawing out the first contact electrode embedded in the inner coating portion to the outside of the inner coating portion can be easily realized by vapor deposition of the hole inner conductor into the contact hole.

[0079] (Appended Note) The embodiments of the present invention have been described above. However, the above-described embodiments do not limit the invention according to the claims. It should also be noted that not all combinations of features described in the embodiments are essential means for solving the problems of the invention. Further, the present invention can be appropriately modified and implemented without departing from its gist.

Explanation of Reference Numerals

[0080] 1... Light-emitting element 2... Semiconductor light-emitting element body 21... Substrate 23... First semiconductor layer 24... Light-emitting layer 25... Second semiconductor layer 26... First contact electrode 27... Second contact electrode 273... Upper surface of the second contact electrode 3... Inner coating portion 30... Organic polymer material 34... Contact hole 4... Outer coating portion 5... First pad electrode 51... Hole inner conductor 6... Second pad electrode H... Length between the upper surface of the second contact electrode and the lower surface of the inner coating portion L... Length of the hole inner conductor T1... Thickness of the inner coating portion T2... Thickness of the first contact electrode Z... Thickness direction of the inner coating portion

Claims

1. A semiconductor light-emitting element body having a first semiconductor layer having a first conductivity type, a light-emitting layer formed on the first semiconductor layer, a second semiconductor layer formed on the light-emitting layer and having a second conductivity type opposite to the first conductivity type, a first contact electrode connected to the first semiconductor layer, and a second contact electrode connected to the second semiconductor layer, an inner coating portion made of an organic polymer material that planarizes the surface of the semiconductor light-emitting element body, an outer coating portion made of an inorganic material that covers the inner coating portion, a first pad electrode connected to the first contact electrode, a second pad electrode connected to the second contact electrode, wherein the inner coating portion covers the surfaces of the first contact electrode, the light-emitting layer, the second semiconductor layer, and the second contact electrode, a contact hole is formed in the inner coating portion that penetrates the inner coating portion in the thickness direction of the inner coating portion and has one end opening toward the first contact electrode, a hole inner conductor that electrically connects the first contact electrode and the first pad electrode is disposed in the contact hole, the area of the cross section of the hole inner conductor orthogonal to the thickness direction is 5% or more and 95% or less of the area of the first contact electrode orthogonal to the thickness direction, the upper surface of the inner coating portion is formed flush with the upper surface of the second contact electrode, a light-emitting element.

2. The cross-sectional area of the hole inner conductor orthogonal to the thickness direction increases toward the side opposite to the first contact electrode side, The light-emitting element according to claim 1.

3. The length of the hole inner conductor in the thickness direction is longer than the thickness of the first contact electrode, The light-emitting element according to claim 1 or 2.

4. The inner coating portion is made of a photoresist, The light-emitting element according to any one of claims 1 to 3.

5. A step of manufacturing a semiconductor light-emitting element body by forming a first semiconductor layer having a first conductivity type, forming a light-emitting layer on the first semiconductor layer, forming a second semiconductor layer having a second conductivity type opposite to the first conductivity type on the light-emitting layer, connecting a first contact electrode to the first semiconductor layer, and connecting a second contact electrode to the second semiconductor layer, a step of covering the surface of the semiconductor light-emitting element body with an inner coating portion made of an organic polymer material so as to planarize the surface of the semiconductor light-emitting element body, forming a contact hole that opens to the first contact electrode in the inner coating portion; covering the inner coating portion with an outer coating portion made of an inorganic material; forming a hole inner conductor electrically connected to the first contact electrode by vapor deposition in the contact hole; having; In the step of covering the semiconductor light-emitting element body with the inner coating portion, the inner coating portion is formed by applying and curing the organic polymer material constituting the inner coating portion on the surface of the semiconductor light-emitting element body. In the step of covering the semiconductor light-emitting element body with the inner coating portion, the surfaces of the first contact electrode, the light-emitting layer, the second semiconductor layer, and the second contact electrode are covered with the inner coating portion. The area of the cross-section of the hole inner conductor perpendicular to the thickness direction of the inner coating portion is 5% or more and 95% or less of the area of the first contact electrode perpendicular to the thickness direction. The upper surface of the inner coating portion is flush with the upper surface of the second contact electrode. A method for manufacturing a light-emitting element.

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