JP7684166B2 - Light emitting device and method for manufacturing the same - Google Patents

Description

The present invention relates to a light-emitting element and a method for manufacturing a light-emitting element.

Patent Document 1 discloses a semiconductor light-emitting element in which a semiconductor light-emitting element body having 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 covered with an insulating layer made of silicon oxide ( _SiO2 ) or the like.

JP 2019-106406 A

In the semiconductor light-emitting element described in Patent Document 1, the insulating layer that constitutes 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 steps and corners on the surface of the semiconductor light-emitting element body, moisture may pass through the cracks and reach the vicinity of the semiconductor light-emitting element body, causing deterioration of the semiconductor light-emitting element body.

The present invention has been made in consideration of the above circumstances, and aims to provide a light-emitting device and a method for manufacturing a light-emitting device that can suppress deterioration of the semiconductor light-emitting device body.

In order to achieve the above object, the present invention provides 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 on the first semiconductor layer, and a second contact electrode connected on the second semiconductor layer, an inner covering part made of an organic polymer material that flattens a surface of the semiconductor light-emitting element body, an outer covering part made of an inorganic material that covers the inner covering part, a first pad electrode connected on the first contact electrode, and a second pad electrode connected on the second contact electrode, the inner covering portion covers the surfaces of the first contact electrode, the light-emitting layer, the second semiconductor layer, and the second contact electrode, the inner covering portion has a contact hole formed therein that penetrates the inner covering portion in the thickness direction of the inner covering portion and has one end opening toward the first contact electrode, the contact hole has an inner-hole conductor arranged within it that electrically connects the first contact electrode and the first pad electrode, the cross-sectional area of the inner-hole conductor perpendicular to the thickness direction is 5% to 95% of the area of the first contact electrode perpendicular to the thickness direction, and the upper surface of the inner covering portion is formed flush with the upper surface of the second contact electrode .

Further, in order to achieve the above object, the present invention provides a method for 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 on the light emitting layer having a second conductivity type opposite to the first conductivity type, connecting a first contact electrode onto the first semiconductor layer, and connecting a second contact electrode onto the second semiconductor layer; covering the surface of the semiconductor light emitting element body with an inner covering part made of an organic polymer material so as to flatten the surface of the semiconductor light emitting element body; forming a contact hole in the inner covering part that opens to the first contact electrode; covering the inner covering part with an outer covering part made of an inorganic material; and forming a conductor hole in the contact hole that is electrically connected to the first contact electrode. and a step of forming an inner-hole conductor by vapor deposition, wherein in the step of covering the semiconductor light-emitting element body with the inner covering portion, the inner covering portion is formed by applying the organic polymer material that constitutes the inner covering portion to the surface of the semiconductor light-emitting element body and curing it, and in the step of covering the semiconductor light-emitting element body with the inner covering portion, 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, a cross-sectional area of the inner-hole conductor perpendicular to a thickness direction of the inner covering portion is 5% to 95% of an area of the first contact electrode perpendicular to the thickness direction, and an upper surface of the inner covering portion is formed flush with an upper surface of the second contact electrode .

The present invention makes it possible to provide a light-emitting element and a method for manufacturing a light-emitting element that can suppress deterioration of the semiconductor light-emitting element body.

1 is a plan view of a light-emitting element according to an embodiment. 2 is a cross-sectional view taken along line II-II of FIG. 1. 4 is a cross-sectional view of the semiconductor light emitting element body after an element body forming step in the embodiment. FIG. 4 is a cross-sectional view of the semiconductor light-emitting element body and the organic polymer material after a first coating step in the embodiment. FIG. 4 is a cross-sectional view of the semiconductor light emitting element body and the inner covering portion after an exposure and development process in the embodiment. FIG. 4 is a cross-sectional view of the semiconductor light emitting element body, the inner covering portion, and the outer covering portion after a second covering step in the embodiment. FIG. 11 is a cross-sectional view of the semiconductor light emitting element body, the inner covering portion, and the outer covering portion after a removal step in the embodiment. FIG.

[Embodiment]
An embodiment of the present invention will be described with reference to Figures 1 to 7. Note that the embodiment described below is shown as a preferred specific example for carrying out the present invention, and while there are some parts that specifically exemplify various technical matters that are technically preferable, the technical scope of the present invention is not limited to this specific embodiment.

(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 in Fig. 1.

The light-emitting element 1 of this embodiment can be, 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 a deep-ultraviolet LED that emits deep-ultraviolet light, and can be used in fields such as sterilization (e.g., air purification, water purification, etc.), medicine (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 the "element body 2"), an inner covering portion 3, an outer covering portion 4, a first pad electrode 5, and a second pad electrode 6.

(Element body 2)
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. The second conductivity type is p-type, and the second semiconductor layer 25 is a layer made of a p-type semiconductor. Furthermore, 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.

Hereinafter, the stacking direction of the multiple semiconductor layers that make up the element body 2 will be referred to as the vertical direction Z, and one side of the vertical direction Z where the semiconductor layers are stacked on the substrate 21 will be referred to as the upper side, and the opposite side will be referred to as the lower side. Note that the expressions "upper" and "lower" are used for convenience and do not limit the position of the light-emitting element 1 relative to the vertical direction, for example, when the light-emitting element 1 is in use.

The substrate 21 is a substrate that transmits light (deep ultraviolet light in this embodiment) emitted by _the light emitting layer 24, and may be, for example, a sapphire ( _Al2O3 ) substrate. Alternatively, for example, an aluminum nitride (AlN) substrate or an aluminum gallium nitride (AlGaN) substrate may be used as the substrate 21.

As the semiconductors constituting the buffer layer 22, the first semiconductor layer 23, the light emitting layer 24 and the second semiconductor layer 25, for example, a binary to quaternary 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 indium-free Al _z Ga _1-z N (0≦z≦1) is often used in deep ultraviolet LEDs.

The buffer layer 22 is formed on the substrate 21. The buffer layer 22 is made of undoped Al _a Ga _1-a 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. However, this is not limited thereto, and the buffer layer 22 can be a single layer. Furthermore, when the substrate 21 is an aluminum nitride substrate or an aluminum gallium nitride substrate, the buffer layer 22 is not necessarily provided.

The first semiconductor layer 23 is formed on the buffer layer 22. The first semiconductor layer 23 is made of Al _b Ga _1-b N (0≦b≦1) doped with n-type impurities. The first semiconductor layer 23 may have a single-layer structure or a multi-layer structure. In a cross-sectional view parallel to the up-down direction (e.g., FIG. 2), the width of the first semiconductor layer 23 is smaller than the width of the buffer layer 22, and the outline of the first semiconductor layer 23 is contained inside the outline of the buffer layer when viewed from above.

The light-emitting layer 24 is formed on a portion 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 FIG. 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 with the second contact electrode 27 in the vertical direction Z. The shape of the second contact electrode 27 will be described later.

The light emitting layer 24 is made of Al _c Ga _1-c 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 multiple 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 to emit light. The light emitting layer 24 is configured to have a band gap of 3.4 eV or more in order to output deep ultraviolet light having a wavelength of 365 nm or less. In particular, in this embodiment, the light emitting layer 24 is configured to generate deep ultraviolet light having a center wavelength of 200 nm or more and 365 nm or less.

The second semiconductor layer 25 is formed on the light emitting layer 24. The second semiconductor layer 25 is made of Al _d Ga _1-d N (0≦d≦1) doped with a p-type impurity. The second semiconductor layer 25 may have a single layer structure or a multi-layer structure.

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 toward the upper side. 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.

A first contact electrode 26 is formed on the exposed upper surface 232 of the first semiconductor layer 23 that is exposed from the light emitting layer 24, and a second contact electrode 27 is formed on the upper surface of the second semiconductor layer 25. The first contact electrode 26 is in ohmic contact with the first semiconductor layer 23, and the second contact electrode 27 is in ohmic contact with the second semiconductor layer 25.

As shown in FIG. 1, the first contact electrode 26 has a first base 261 extending in a direction perpendicular to the vertical direction Z, and a first protrusion 262 protruding from multiple locations of the first base 261 toward the second contact electrode 27. The second contact electrode 27 has a second base 271 formed substantially parallel to the first base 261, and a second protrusion 272 protruding from multiple locations of the second base 271 toward the first contact electrode 26. When viewed from above, multiple second protrusions 272 are inserted between adjacent first protrusions 262, so that the first contact electrode 26 and the second contact electrode 27 are interdigitated with each other. Hereinafter, the direction perpendicular to the vertical direction Z and in which the first base 261 and the second base 271 extend is referred to as the horizontal direction X, and the direction perpendicular to both the vertical direction Z and the horizontal direction X is referred to as the vertical direction Y. The vertical direction Y is the direction in which the first protrusion 262 and the second protrusion 272 each extend.

The element body 2 is not limited to the configuration described above, and a general element body 2 configuration can be adopted.

(Inner covering portion 3)
The inner coating 3 covers the surface of the element body 2, thereby filling in and flattening steps and corners present in the surface shape of the element body 2. The inner coating 3 can be made of an organic polymer material having electrical insulation properties. In this embodiment, the inner coating 3 is made of photoresist. Either a positive type or a negative type photoresist can be used.

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. 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 corners that may be formed in each of the first contact electrode 26, the light emitting layer 24, the second semiconductor layer 25, and the second contact electrode 27. The outer surface 31 of the inner covering portion 3 (i.e., the surface in contact with the outer covering portion 4) is configured to be flatter than the inner surface 32 of the inner covering portion 3 (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). The outer surface 31 of the inner covering part 3 has an upper surface 311 that is perpendicular to the vertical direction Z, and a side surface 312 that is parallel to the vertical direction Z. A corner 313 between the upper surface 311 and the side surface 312 is formed into a curved surface with rounded corners. Note that the side surface 312 of the outer surface 31 of the inner covering part 3 may be inclined outward, for example, toward the lower side.

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 if 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 with each other, 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 misaligned due to manufacturing tolerances, etc., 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 with each other. The upper surface 273 of the second contact electrode 27 is exposed from the inner covering portion 3 to ensure electrical continuity with the second pad electrode 6.

The inner covering portion 3 is formed with a plurality of contact holes 34 penetrating the inner covering portion 3 in the vertical direction Z. 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 open toward the first contact electrode 26. The plurality of contact holes 34 have the same shape and are formed at equal intervals. As shown in FIG. 1, the plurality of contact holes 34 opening into the first base portion 261 of the first contact electrode 26 are provided at equal intervals in the horizontal direction X, and the plurality of contact holes 34 opening into the first protrusion portion 262 of the second contact electrode 27 are formed at equal intervals in the vertical direction Y. The term "equal intervals" is not limited to strictly equal intervals, and includes, for example, approximately equal intervals in which the difference between the maximum and minimum values of the intervals between adjacent contact holes 34 is 10% or less of the maximum value.

2, the contact hole 34 is formed long in the vertical direction Z. In this embodiment, the length of the contact hole 34 in the vertical direction Z (which in this embodiment is equivalent to the length L of the hole conductor 51 described below) is longer than the thickness T2 of the first contact electrode 26. The contact hole 34 is formed in a tapered shape (in this embodiment, a truncated cone shape) whose inner diameter increases toward the upper side.

In this embodiment, the inner coating part 3 has a single-layer structure, but it may have a multi-layer structure. In addition, the inner coating part 3 is made of photoresist, but it can also be made of, for example, an organic material other than photoresist.

(Outer covering part 4)
The outer coating part 4 is formed above the buffer layer 22 and covers the inner coating part 3. The outer coating part 4 is made of an inorganic material that is electrically insulating and difficult for moisture to pass through. In this embodiment, the outer coating part 4 is made of silicon dioxide (SiO ₂ ).

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. The outer covering portion 4 is formed with a first opening 41 on the inside of which a first pad electrode 5 is formed, and a second opening 42 on the inside of which a second pad electrode 6 is formed. The first opening 41 is formed in a position facing the first contact electrode 26 in the vertical direction Z, and the second opening 42 is formed in a position facing the second contact electrode 27 in the vertical direction Z.

In this embodiment, the outer coating portion 4 consists of one layer, but it may also consist of multiple layers.

(First Pad Electrode 5 and 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 first base portion 261 side of the first contact electrode 26 relative to the center position in the vertical direction Y of the light-emitting element 1, and the second pad electrode 6 is formed in a region on the second base portion 271 side of the second contact electrode 27 relative to the central position.

The first pad electrode 5 is integrally composed of an in-hole conductor 51 formed to fill the contact hole 34, a first embedded portion 52 embedded in the first opening 41 of the outer coating portion 4, and a first exposed portion 53 exposed upward from the outer coating portion 4.

The hole conductor 51 is filled in each contact hole 34. Therefore, the shape of the hole conductor 51 is the same as the shape of the inner region of the contact hole 34 in which the hole conductor 51 is arranged. The hole conductor 51 is formed long in the vertical direction Z. The length L of the hole conductor 51 in the vertical direction Z is longer than the thickness T2 of the first contact electrode 26, and is preferably three times longer than the thickness T2 of the first contact electrode 26. In addition, the hole conductor 51 is formed in a tapered shape (in this embodiment, a truncated cone shape) in which the area of the cross section perpendicular to the vertical direction Z becomes larger toward the upper part, similar to the shape of the inner region of the contact hole 34. The area of the cross section of the hole conductor 51 perpendicular to the vertical direction Z is preferably less than 100% of the area of the first contact electrode 26 perpendicular to the vertical direction Z, and more preferably 5% to 95% of the area of the first contact electrode 26 perpendicular 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. In the case where a plurality of in-hole conductors 51 are formed as in this embodiment, the cross-sectional area of the in-hole conductors 51 perpendicular to the vertical direction Z means the sum of the cross-sectional areas of all the in-hole conductors 51 perpendicular to the vertical direction Z. In addition, in the case where each in-hole conductor 51 is formed in a tapered shape as in this embodiment, the cross-sectional area of the in-hole conductor 51 at each position in the vertical direction Z is preferably less than 100% of the area of the first contact electrode 26 perpendicular to the vertical direction Z, and more preferably 5% to 95%. The lower end of the in-hole conductor 51 is electrically connected to the first contact electrode 26.

The first buried portion 52 is formed to fill the first opening 41, and its lower end is connected to the upper end of each in-hole conductor 51. Although not shown, the first buried portion 52 is formed in a comb-shaped region below the first exposed portion 53 and facing the first contact electrode 26 in the vertical direction Z.

The first exposed portion 53 is formed so that its shape when viewed from above is a generally rectangular shape that is elongated in the horizontal direction X, and its lower end is connected to the first buried portion 52.

The second pad electrode 6 is integrally formed with 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.

The second buried portion 61 is formed to fill 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 buried portion 61 is formed in a comb-shaped region below the second exposed portion 62 and facing the second contact electrode 27 in the vertical direction Z.

The second exposed portion 62 is formed so that its shape when viewed from above is a generally rectangular shape that is elongated in the horizontal direction X, and its lower end is connected to the second buried portion 61. The first exposed portion 53 and the second exposed portion 62 are arranged side by side with a gap in the vertical direction Y.

In the above example, the first pad electrode 5 and the second pad electrode 6 are each made of a single member, but they may be made of multiple members connected in the vertical direction Z, etc.

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, for example, on an electrode of a submount (not shown). For example, the light-emitting element 1 is flip-chip mounted on the electrode of the submount via a gold (Au) bump or the like, with the substrate 21 positioned on the opposite side to the submount. In this case, the light emitted from the light-emitting element 1 is mainly extracted from the substrate 21 of the element body 2 to the opposite side to the submount.

(Method of Manufacturing Light-Emitting Element 1)
Next, an example of a method for manufacturing the light-emitting element 1 of this embodiment will be described.
The manufacturing method of the light-emitting element 1 includes an element body forming step, a first covering step, an exposure and development step, a second covering step, a removal step, and a pad electrode forming step. Fig. 3 is a cross-sectional view of the element body 2 after the element body forming step. Fig. 4 is a cross-sectional view of the element body 2 and the organic polymer material 30 after the first covering step. Fig. 5 is a cross-sectional view of the element body 2 and the inner covering portion 3 after the exposure and development step. Fig. 6 is a cross-sectional view of the element body 2, the inner covering portion 3, and the outer covering portion 4 after the second covering step. Fig. 7 is a cross-sectional view of the element body 2, the inner covering portion 3, and the outer covering portion 4 after the removal step.

In the element body formation process, the buffer layer 22, the first semiconductor layer 23, the light emitting layer 24, and the second semiconductor layer 25 are formed on the 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 for epitaxially growing each layer, such as the growth temperature, growth pressure, and growth time, can be general conditions according to the configuration of each layer.

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 location on the upper surface of the second semiconductor layer 25. Then, the second semiconductor layer 25 and the light emitting layer 24 formed in 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 the exposed upper surface 232 is formed, the mask is removed.

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 a well-known method such as an electron beam deposition method or a sputtering method. A cross-sectional view of the element body 2 after the element body formation process is shown in FIG. 3.

Next, as shown in FIG. 4, the first coating step is performed. In the first coating step, the liquid organic polymer material 30 constituting the inner coating portion 3 is applied so as to cover the upper portion of the buffer layer 22 in the element body 2. Various methods such as spray coating and spin coating can be used as the coating method. In the first coating step, the upper surface 273 of the second contact electrode 27 is exposed upward from the inner coating portion 3. Note that 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, the organic polymer material 30 formed on the upper side of the second contact electrode 27 is removed in the subsequent exposure and development step to expose the upper surface 273 of the second contact electrode 27.

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, the organic polymer material 30 is removed from the portion not located above the first semiconductor layer 23 and the portion that will become the contact hole 34. If the organic polymer material 30 is a negative photoresist, the organic polymer material 30 is exposed from above and developed except for the portion that is removed in the exposure and development process. As a result, the exposed portion of the organic polymer material 30 remains after development and becomes the inner coating portion 3. Due to the diffusion of light during exposure, the contact hole 34 after development is formed so that the inner diameter becomes smaller toward the bottom. Also, if the organic polymer material 30 is a positive photoresist, the organic polymer material 30 is exposed from above and developed except for the portion that is removed in the exposure and development process. As a result, the organic polymer material 30 remains after development except for the exposed portion, becoming the inner coating portion 3. During exposure, the upper part of the organic polymer material 30 that will become the contact hole 34 is exposed to more intense light, so the contact hole 34 after development is formed so that the inner diameter becomes smaller as it approaches the bottom. The state after the exposure and development process is shown in Figure 5.

Next, as shown in FIG. 6, a second coating step is performed. In the second coating step, the outer coating portion 4 is formed in the region above 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, which are exposed immediately before the second coating step (i.e., the state shown in FIG. 5).

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

Next, a pad electrode forming process is performed. In the pad electrode forming process, although not shown, a mask is formed on the upper surface of the outer covering portion 4 at locations other than the locations where the first pad electrode 5 and the second pad electrode 6 are to be 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 the contact hole 34, the first opening 41, the second opening 42, and a space formed in the mask (not shown) in order from the bottom, so that the first pad electrode 5 and the second pad electrode 6 are formed as shown in FIG.
In this manner, the light emitting device 1 of the present embodiment can be manufactured.

(Functions and Effects of the Embodiments)
The light emitting element 1 of this embodiment has an element body 2, an inner covering part 3 that flattens the surface of the element body 2, and an outer covering part 4 made of an inorganic material that covers the inner covering part 3. In this way, the outer covering part 4 made of an inorganic material that is relatively prone to cracking does not directly cover the surface of the element body 2, which has steps and corners, but rather covers the element body 2 that has been flattened by the inner covering part 3 with the outer covering part 4, thereby making it possible to prevent cracks from occurring in the outer covering part 4. If cracks occur in the outer covering part 4, for example, moisture may pass through the cracks, which may cause deterioration of the element body 2. However, according to the configuration of this embodiment, the waterproofness of the light emitting element 1 can be improved, and as a result, deterioration of the element body 2 can be suppressed.

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. These are prone to forming steps or corners, so the configuration of this embodiment can further prevent cracks from occurring in the outer covering portion 4.

In addition, the inner covering portion 3 is formed with a contact hole 34 that penetrates the inner covering portion 3 in the thickness direction (i.e., the vertical direction Z) of the inner covering portion 3 and has one end open toward the first contact electrode 26. An in-hole conductor 51 that electrically connects the first contact electrode 26 and the first pad electrode 5 is arranged in the contact hole 34. Therefore, the first contact electrode 26 and the first pad electrode 5 can be electrically connected through the in-hole conductor 51 in the contact hole 34. As a result, in order to draw the first contact electrode 26 to the outside of the inner covering 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 the following is achieved: reduction in material cost, weight reduction, and reduction in manufacturing time for the first contact electrode 26.

In addition, the cross-sectional area of the hole conductor 51 perpendicular to the vertical direction Z is 5% to 95% of the area of the first contact electrode 26 perpendicular to the vertical direction Z. By making the cross-sectional area of the hole conductor 51 perpendicular to the vertical direction Z 95% or less of the area of the first contact electrode 26 perpendicular to the vertical direction Z, at least one of reducing the material cost, weight, and manufacturing time of the hole conductor 51 can be achieved. In addition, by making the cross-sectional area of the hole conductor 51 perpendicular to the vertical direction Z 5% or more of the area of the first contact electrode 26 perpendicular to the vertical direction Z, the electrical resistivity of the hole conductor 51 can be prevented from becoming excessively high.

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. By making the thickness T1 of the inner covering portion 3 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 covering portion 3. Furthermore, by making the thickness T1 of the inner covering portion 3 1.2H or less, the material cost and weight of the inner covering portion 3 can be reduced.

The cross-sectional area of the conductor 51 perpendicular to the vertical direction Z becomes larger on the opposite side (i.e., the upper side) of the first contact electrode 26. In other words, the conductor 51 on the side connected to the first embedded portion 52 of the first pad electrode 5 becomes larger, so that the conductor 51 is prevented from breaking.

The length L of the 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, the first contact electrode 26 and the first pad electrode 5 can be electrically connected without forming the first contact electrode 26 thick, making it easier to achieve at least one of reducing the material cost of the first contact electrode 26, reducing its weight, and reducing the manufacturing time.

The inner coating 3 is also made of photoresist. This makes it easy to form the contact holes 34.

The inner coating 3 is made of an organic polymer material. Compared to inorganic materials, organic polymer materials are less susceptible to cracking, so it is possible to prevent cracks from occurring in the inner coating 3 starting from steps or corners on the surface of the element body 2.

In addition, in the process of covering the element body 2 with the inner covering portion 3 in the manufacturing method of the light-emitting element 1, the inner covering portion 3 is formed by applying the organic polymer material 30 that constitutes the inner covering portion 3 to the surface of the element body 2 and curing it. In this way, by forming the inner covering portion 3 by a coating method, it is easy to flatten the surface of the element body 2 with the inner covering portion 3.

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

As described above, this embodiment can provide a light-emitting element and a method for manufacturing a light-emitting element that can suppress deterioration of the element body.

(Summary of the embodiment)
Next, the technical ideas grasped from the above-described embodiment will be described by using the reference numerals and the like in the embodiment. However, the reference numerals and the like in the following description do not limit the components in the claims to the members and the like specifically shown in the embodiment.

[1] A first embodiment of the present invention is a light-emitting element (1) comprising a semiconductor light-emitting element body (2), an inner covering portion (3) that flattens the surface of the semiconductor light-emitting element body (2), and an outer covering portion (4) made of an inorganic material that covers the inner covering portion (3).
This makes it possible to suppress deterioration of the semiconductor light emitting element body.

[2] A second embodiment of the present invention is characterized in that, in the first embodiment, the semiconductor light-emitting element body (2) has 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 covering portion (3) covers surfaces of the first contact electrode (26), the light-emitting layer (24), the second semiconductor layer (25), and the second contact electrode (27).
This can prevent cracks from occurring in the outer coating portion.

[3] A third embodiment of the present invention is the second embodiment, further comprising a first pad electrode (5) connected onto the first contact electrode (26) and a second pad electrode (6) connected onto the second contact electrode (27), wherein a contact hole (34) is formed in the inner covering portion (3) penetrating the inner covering portion (3) in the thickness direction (Z) of the inner covering portion (3) and having one end opening toward the first contact electrode (26), and an inner-hole conductor (51) is arranged within the contact hole (34) to electrically connect the first contact electrode (26) and the first pad electrode (5).
This achieves at least one of a reduction in material cost for the first contact electrode, a reduction in weight, and a reduction in manufacturing time.

[4] A fourth embodiment of the present invention is the third embodiment, in which the area of a cross section of the inner-hole conductor (51) perpendicular to the thickness direction (Z) is 5% to 95% of the area of the first contact electrode (26) perpendicular to the thickness direction (Z).
This makes it possible to achieve at least one of reducing the material cost of the in-hole conductor, reducing its weight, and reducing the manufacturing time, while also preventing the electrical resistivity of the in-hole conductor from becoming excessively high.

[5] A fifth embodiment of the present invention is the third or fourth embodiment, in which, 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 covering portion (3) is H, the thickness T1 of the inner covering portion (3) satisfies 0.8H≦T1≦1.2H.
This allows the first contact electrode, the light-emitting layer, the second semiconductor layer, and most of the second contact electrode to be covered by the inner covering part 3, while also reducing the material costs and weight of the inner covering part 3.

[6] A sixth embodiment of the present invention is any one of the third to fifth embodiments, in which the area of a cross section of the inner-hole conductor (51) perpendicular to the thickness direction (Z) becomes larger on the opposite side to the first contact electrode (26).
This prevents the conductor in the hole from breaking.

[7] A seventh embodiment of the present invention is any one of the third to sixth embodiments, wherein the length (L) of the inner-hole conductor (51) in the thickness direction (Z) is longer than the thickness (T2) of the first contact electrode (26).
This makes it easier to achieve at least one of reducing the material cost of the first contact electrode, reducing its weight, and reducing the manufacturing time.

[8] An eighth embodiment of the present invention is any one of the third to seventh embodiments, in which the inner covering portion (3) is made of photoresist.
This makes it possible to easily form the contact holes.

[9] A ninth embodiment of the present invention is any one of the first to eighth embodiments, in which the inner covering portion (3) is made of an organic polymer material (30).
This can prevent cracks from occurring in the inner covering portion.

[10] A tenth embodiment of the present invention is a method for manufacturing a light-emitting element (1), comprising the steps of manufacturing a semiconductor light-emitting element body (2), covering the surface of the semiconductor light-emitting element body (2) with an inner covering portion (3) so as to planarize the surface of the semiconductor light-emitting element body (2), and covering the inner covering portion (3) with an outer covering portion (4) made of an inorganic material.
This makes it possible to manufacture a light emitting element in which deterioration of the semiconductor light emitting element body is suppressed.

[11] An eleventh embodiment of the present invention is the tenth embodiment, in which the inner covering portion (3) is made of an organic polymer material (30), and in the process of covering the semiconductor light-emitting element body (2) with the inner covering portion (3), the organic polymer material (30) constituting the inner covering portion (3) is applied to the surface of the semiconductor light-emitting element body (2) and hardened to form the inner covering portion (3).
This makes it easier for the inner covering portion to flatten the surface of the semiconductor light emitting element body.

[12] A twelfth embodiment of the present invention is the eleventh embodiment, in which, 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), and a front end of the semiconductor light-emitting element body (2) is formed. The process of covering the above-mentioned surfaces with the inner covering portion (3) includes covering the surfaces of the first contact electrode (26), the light emitting layer (24), the second semiconductor layer (25), and the second contact electrode (27) with the inner covering portion (3), and further including the steps of forming a contact hole (34) in the inner covering portion (3) that opens to the first contact electrode (26), and forming an inner-hole conductor (51) electrically connected to the first contact electrode (26) within the contact hole (34) by vapor deposition.
This makes it possible to easily realize a configuration in which the first contact electrode embedded in the inner covering portion is electrically led out to the outside of the inner covering portion by vapor deposition of an in-hole conductor into the contact hole.

(Additional Note)
Although the embodiment of the present invention has been described above, the invention according to the claims is not limited to the above embodiment. It should be noted that not all of the combinations of features described in the embodiment are essential to the means for solving the problems of the invention. The present invention can be modified appropriately without departing from the spirit of the invention.

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...Top surface of second contact electrode 3...Inner covering portion 30...Organic polymer material 34...Contact hole 4...Outer covering portion 5...First pad electrode 51...In-hole conductor 6...Second pad electrode H...Length L between top surface of second contact electrode and bottom surface of inner covering portion...Length T1 of inner covering portion T2...Thickness Z of first contact electrode...Thickness direction of inner covering portion

Claims (5)

a semiconductor light emitting element body 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 onto the first semiconductor layer, and a second contact electrode connected onto the second semiconductor layer;
an inner covering portion made of an organic polymer material that flattens 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 onto the first contact electrode;
a second pad electrode connected onto the second contact electrode;
the inner covering portion covers 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 covering portion, the contact hole penetrating the inner covering portion in a thickness direction of the inner covering portion and having one end opening toward the first contact electrode,
an inner-hole conductor is disposed in the contact hole, the inner hole electrically connecting the first contact electrode and the first pad electrode;
a cross-sectional area of the inner-hole conductor perpendicular to the thickness direction is 5% to 95% of an area of the first contact electrode perpendicular to the thickness direction,
an upper surface of the inner covering portion is formed flush with an upper surface of the second contact electrode;
Light emitting element. the inner-hole conductor has a cross-sectional area perpendicular to the thickness direction that is larger on the opposite side to the first contact electrode;
The light-emitting device according to claim 1 . a length of the inner-hole conductor in the thickness direction is longer than a thickness of the first contact electrode;
The light-emitting device according to claim 1 . The inner coating portion is made of photoresist.
The light-emitting device according to claim 1 . a step of manufacturing a semiconductor light emitting device 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 onto the first semiconductor layer, and connecting a second contact electrode onto the second semiconductor layer;
covering the surface of the semiconductor light emitting device body with an inner covering portion made of an organic polymer material so as to planarize the surface of the semiconductor light emitting device body;
forming a contact hole in the inner covering portion, the contact hole opening to the first contact electrode;
covering the inner coating portion with an outer coating portion made of an inorganic material;
forming an in-hole conductor electrically connected to the first contact electrode within the contact hole by vapor deposition;
having
In the step of covering the semiconductor light emitting element body with the inner covering portion, the organic polymer material constituting the inner covering portion is applied to the surface of the semiconductor light emitting element body and cured to form the inner covering portion;
In the step of covering the semiconductor light emitting element body with the inner covering portion, 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;
a cross-sectional area of the in-hole conductor perpendicular to a thickness direction of the inner covering portion is 5% to 95% of an area of the first contact electrode perpendicular to the thickness direction,
an upper surface of the inner covering portion is formed flush with an upper surface of the second contact electrode;
A method for manufacturing a light-emitting device.

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