JP7425955B2 - Light-emitting device and method for manufacturing the light-emitting device - Google Patents

Description

The present invention relates to a light emitting device and a method of manufacturing the light emitting device.

A mounting board, a semiconductor structure including an active layer mounted on the mounting board, and a light-transmitting member covering above the semiconductor structure and the space around the semiconductor structure on the mounting board. In a light emitting device, improvement in the efficiency of light extraction from a translucent member is required.

JP2018-93136A

Embodiments of the present invention aim to provide a light-emitting device and a method of manufacturing the light-emitting device that can improve light extraction efficiency.

According to one aspect of the present invention, a light emitting device includes a first substrate that is transparent and has a first surface and a second surface located on the opposite side of the first surface, and the first substrate. The substrate has a third surface opposite to the first surface of the first substrate, and a fourth surface located on the opposite side of the third surface, and includes an active layer. a semiconductor structure including a semiconductor structure; an electrode disposed on the fourth surface of the semiconductor structure and electrically connected to the semiconductor structure; and a semiconductor structure disposed on the first surface of the first substrate; a metal member disposed apart from the semiconductor structure in a first direction parallel to the first surface of the substrate; and a metal member facing the first surface of the first substrate and the fourth surface of the semiconductor structure. a first bonding member disposed between the second substrate and the electrode and electrically connected to the electrode; and a first bonding member disposed between the second substrate and the metal member and connected to the metal member. a second bonding member bonded to a member, the second surface of the first substrate has a plurality of convex portions, and overlaps at least the third surface of the second surface when viewed from above. a second region located between the first region and the outer edge of the second surface and having a surface roughness smaller than that of the first region, , a boundary between the first region and the second region is located between an outer edge of the third surface of the semiconductor structure and an inner edge of the metal member.
According to one aspect of the present invention, a method for manufacturing a light emitting device includes a first substrate having a first surface and a second surface located on the opposite side of the first surface, the second surface comprising: the first substrate having a first region having a plurality of convex portions and a second region having a surface roughness smaller than the first region; preparing a wafer having a semiconductor structure having three sides and a fourth side opposite to the third side; removing a portion of the semiconductor structure; a step of exposing a portion from the semiconductor structure; a step of forming an electrode on the fourth surface of the semiconductor structure; a portion of the first surface overlapping the second region of the second surface; forming a metal member spaced apart from the semiconductor structure in a first direction parallel to the first surface; and cutting the first substrate by irradiating the second region of the first substrate with a laser beam. the first surface of the first substrate and the semiconductor structure, the metal member being located between the cutting position of the first substrate and the semiconductor structure in the first direction; The fourth surface of the structure faces the second substrate, a first bonding member electrically connected to the electrode is formed between the electrode and the second substrate, and the metal member and the second bonding member are formed between the electrode and the second substrate. The method includes a step of joining the first substrate and the second substrate by forming a second joining member between the substrates.

According to embodiments of the present invention, it is possible to provide a light-emitting device and a method for manufacturing a light-emitting device that can improve light extraction efficiency.

FIG. 1 is a cross-sectional view of a light emitting device according to a first embodiment. FIG. 2 is a top view of the light emitting device of the first embodiment. FIG. 3 is a cross-sectional view for explaining one step of the method for manufacturing the light emitting device of the first embodiment. FIG. 3 is a cross-sectional view for explaining one step of the method for manufacturing the light emitting device of the first embodiment. FIG. 3 is a cross-sectional view for explaining one step of the method for manufacturing the light emitting device of the first embodiment. FIG. 3 is a cross-sectional view for explaining one step of the method for manufacturing the light emitting device of the first embodiment. FIG. 3 is a cross-sectional view of a light emitting device according to a second embodiment. FIG. 7 is a sectional view of a light emitting device according to a third embodiment. FIG. 7 is a cross-sectional view of a light emitting device according to a fourth embodiment. It is a top view of the light emitting device of 4th embodiment. It is a graph showing a first simulation result. It is a graph showing the measurement results of light transmittance. It is a graph showing a second simulation result. It is a graph showing a third simulation result.

Hereinafter, embodiments will be described with reference to the drawings. In each drawing, the same components are designated by the same reference numerals. Note that each drawing schematically shows an embodiment, so the scale, spacing, positional relationship, etc. of each member may be exaggerated, or illustration of some members may be omitted. Moreover, as a sectional view, an end view showing only a cut surface may be shown.

In the following description, components having substantially the same functions are indicated by common reference numerals, and the description thereof may be omitted. In addition, terms indicating a specific direction or position (eg, "above", "below", and other terms including those terms) may be used. However, these terms are used only for clarity of relative orientation or position in the referenced drawings. If the relative directions or positional relationships using terms such as "upper" and "lower" in the referenced drawings are the same, the arrangement may not be the same in drawings other than this disclosure, actual products, etc. as in the referenced drawings. It's okay. In this specification, "parallel" refers not only to cases in which two straight lines, sides, planes, etc. do not intersect even if extended, but also to cases in which two lines, sides, planes, etc. intersect within an angle of 10°. Also included. In this specification, the positional relationship expressed as "above" includes cases in which they are in contact with each other, and cases in which they are not in contact with each other but are located above.

[First embodiment]
FIG. 1 is a sectional view of a light emitting device 1 of the first embodiment. FIG. 2 is a top view of the light emitting device 1 of the first embodiment. FIG. 1 is a sectional view taken along line II in FIG. 2.

The light emitting device 1 includes a first substrate 10, a semiconductor structure 20, an electrode 31, a metal member 32, a second substrate 50, a first bonding member 41, and a second bonding member 42.

The semiconductor structure 20 has, for example, a chemical formula of In _x Al _y Ga _1-x-y N (0≦x≦1, 0≦y≦1, x+y≦1) with composition ratios x and y within their respective ranges. Contains semiconductors of all varied compositions. Semiconductor structure 20 includes an n-side layer, a p-side layer, and an active layer 21 disposed between the n-side layer and the p-side layer. The active layer 21 can emit ultraviolet light. The active layer 21 emits light having a peak wavelength of 400 nm or less, for example.

The first substrate 10 is transparent to light from the active layer 21 . As the first substrate 10, for example, a sapphire substrate can be used. The first substrate 10 has a first surface 11 . A direction parallel to the first surface 11 of the first substrate 10 is defined as a first direction X. A direction parallel to the first surface 11 of the first substrate 10 and orthogonal to the first direction X is defined as a second direction Y. The direction from the second substrate 50 toward the first substrate 10 is defined as a third direction Z. The third direction Z is orthogonal to the first direction X and the second direction Y. The first substrate 10 has a second surface 12 located on the opposite side of the first surface 11 in the third direction Z. The thickness of the first substrate 10 (the shortest distance from the first surface 11 of the first substrate 10 to the highest point of the second surface 12 of the first substrate 10 in the third direction Z) is, for example, 300 μm or more and 1000 μm or less It can be done.

The semiconductor structure 20 is placed on a part of the first surface 11 of the first substrate 10 . The semiconductor structure 20 has a third surface 23 facing the first surface 11 of the first substrate 10 and a fourth surface 24 located on the opposite side of the third surface 23 in the third direction Z. In the third direction Z, the third surface 23 of the semiconductor structure 20 is located between the first surface 11 of the first substrate 10 and the fourth surface 24 of the semiconductor structure 20 . Furthermore, the semiconductor structure 20 has a side surface 25 that connects the third surface 23 and the fourth surface 24 .

The electrode 31 is disposed on the fourth surface 24 of the semiconductor structure 20 and is electrically connected to the semiconductor structure 20 . An electrode 31 that is electrically connected to the p-side layer of the semiconductor structure 20 and functions as an anode electrode, and an electrode 31 that is electrically connected to the n-side layer of the semiconductor structure 20 and functions as a cathode electrode are arranged in the first direction. They are arranged on the fourth surface 24 of the semiconductor structure 20 and spaced apart in the direction X. As the material for the electrode 31, for example, gold or copper can be used.

The metal member 32 is arranged on the first surface 11 of the first substrate 10 and separated from the semiconductor structure 20 in the first direction X. As the material of the metal member 32, for example, titanium or platinum can be used. The metal member 32 may have, for example, a laminated structure in which a platinum layer and a titanium layer are laminated in order from the first surface 11 of the first substrate 10.

The second substrate 50 faces the first surface 11 of the first substrate 10 and the fourth surface 24 of the semiconductor structure 20 . The second substrate 50 is made of an insulating material. As the material of the second substrate 50, for example, aluminum nitride can be used. Wiring lines 51 and 52 are arranged on the surface of the second substrate 50. Here, the surface of the second substrate 50 is a surface facing the first surface 11 of the first substrate 10 and the fourth surface 24 of the semiconductor structure 20. The wirings 51 and 52 face the first surface 11 of the first substrate 10 and the fourth surface 24 of the semiconductor structure 20. Further, as the material for the wirings 51 and 52, for example, nickel, gold, or an alloy thereof can be used. The wirings 51 and 52 may have, for example, a laminated structure in which a nickel layer and a gold layer are laminated in order from the surface side of the second substrate 50. The wirings 51 and 52 may be formed all at once using the same material.

The first bonding member 41 is disposed between the second substrate 50 and the electrode 31 in the third direction Z, and is electrically connected to the electrode 31. Further, the first bonding member 41 is electrically connected to a wiring 51 arranged on the surface of the second substrate 50. The semiconductor structure 20 is electrically connected to the wiring 51 arranged on the surface of the second substrate 50 via the electrode 31 and the first bonding member 41 . As the material of the first joining member 41, for example, gold, silver, copper, or an alloy thereof can be used. Further, as the material of the first joining member 41, for example, a gold-tin alloy having a tin (Sn) content of 20% by weight or more and 30% by weight or less can be used.

The second bonding member 42 is arranged between the second substrate 50 and the metal member 32 in the third direction Z. The metal member 32 and the second substrate 50 are joined by the second joining member 42 . As the material of the second joining member 42, for example, the same material as the material of the first joining member 41 can be used.

The second bonding member 42 is electrically connected to wiring 52 arranged on the surface of the second substrate 50. Wiring 51 and wiring 52 are not electrically connected. As shown in FIG. 2, the second bonding member 42 continuously surrounds the semiconductor structure 20 in a top view. The metal member 32 to which the second bonding member 42 is bonded also continuously surrounds the semiconductor structure 20 in a top view. The wiring 52 to which the second bonding member 42 is bonded also continuously surrounds the semiconductor structure 20 in a top view. The metal member 32 is also separated from the semiconductor structure 20 in the second direction Y. The second bonding member 42 and the metal member 32 continuously surround the side surface 25 of the semiconductor structure 20 when viewed from above.

The semiconductor structure 20 is arranged in a space 90 defined by the first substrate 10 , the second substrate 50 , the second bonding member 42 , and the metal member 32 . The space 90 is hermetically sealed from the space outside the light emitting device 1 by the first substrate 10, the second substrate 50, the second bonding member 42, and the metal member 32. Thereby, oxidation of the semiconductor structure 20, corrosion of the electrode 31, etc. can be reduced.

Note that the second bonding member 42 can also be disposed discontinuously around the semiconductor structure 20 when viewed from above. Further, the metal member 32 to which the second bonding member 42 is bonded can also be disposed discontinuously around the semiconductor structure 20 in a top view. For example, the semiconductor structure 20 may be surrounded by a plurality of metal members 32 and a plurality of second bonding members 42. Further, for example, when viewed from above, the metal members 32 may be arranged continuously, and the second bonding members 42 may be arranged discontinuously. In this case, the space between the first substrate 10 and the second substrate 50 in which the semiconductor structure 20 is located communicates with the space outside the light emitting device 1 .

Light from the active layer 21 is mainly extracted to the outside of the light emitting device 1 through the second surface 12 of the first substrate 10 . The second surface 12 of the first substrate 10 has a first region 12-1 and a second region 12-2. In a top view, the first region 12-1 is adjacent to the second region 12-2. Furthermore, in a top view, the second region 12-2 is located in an annular shape so as to surround the first region 12-1. When viewed from above, the first region 12-1 is preferably located at the center of the first substrate 10. The first region 12-1 has a plurality of convex portions 12a. In a top view, the plurality of convex portions 12a are preferably arranged over the entire surface of the first region 12-1. The shape of the first region 12-1 in a top view is, for example, a rectangle. The first region 12-1 is arranged to overlap at least the third surface 23 of the semiconductor structure 20 of the second surface 12 when viewed from above. Thereby, light from the active layer 21 can be efficiently extracted from the second surface 12, and the extraction efficiency of the light emitting device 1 can be improved. Further, the second region 12-2 is arranged to overlap the metal member 32 when viewed from above.

The semiconductor structure 20 can be formed on the first surface 11 of the first substrate 10 by, for example, MOCVD (metal organic chemical vapor deposition). The first substrate 10 used to form the semiconductor structure 20 is also used as a member that closes the upper part of the space 90 (+Z side in FIG. 1). Therefore, in the light emitting device 1, there is no air layer in the path from the third surface 23 of the semiconductor structure 20 to the second surface 12 of the first substrate 10, which is the main light extraction surface of the light emitting device 1. Deterioration in light extraction efficiency due to total reflection at the interface between the air layer and other members is less likely to occur. According to the first embodiment, light directed upward from the third surface 23 of the semiconductor structure 20 can be directly extracted from the second surface 12 of the first substrate 10 to the outside of the light emitting device 1 without passing through an air layer. I can do it.

The second region 12-2 is located between the first region 12-1 and the outer edge 12b of the second surface 12, and has a smaller surface roughness than the first region 12-1. For example, the height of the convex portion 12a of the first region 12-1 can be set to 0.5 μm or more and 2 μm or less. Further, for example, the height of the convex portion of the second region 12-2 can be less than 0.5 μm. The convex portion 12 may not be arranged in the second region 12-2.

In the first direction do. In FIG. 2, the boundary 15 between the first region 12-1 and the second region 12-2 is represented by a two-dot chain line. Also in the second direction Y, the boundary 15 between the first region 12-1 and the second region 12-2 is between the outer edge 23a of the third surface 23 of the semiconductor structure 20 and the inner edge 32a of the metal member 32. To position. The boundary 15 between the first region 12-1 and the second region 12-2 is located at a position that continuously surrounds the semiconductor structure 20 when viewed from above. The outer edge 23a of the third surface 23 of the semiconductor structure 20 and the inner edge 32a of the metal member 32 are separated in the first direction X and the second direction Y.

A portion 11 a of the first surface 11 of the first substrate 10 is exposed to the space 90 in a region between the outer edge 23 a of the third surface 23 of the semiconductor structure 20 and the inner edge 32 a of the metal member 32 . As will be described later, after the semiconductor structure 20 is formed on the entire first surface 11 of the first substrate 10, a part of the semiconductor structure 20 is removed, thereby forming a part of the first surface 11 of the first substrate 10. The portion 11a is exposed from the semiconductor structure 20.

By exposing a portion 11a of the first surface 11 located outside the outer edge 23a of the third surface 23 of the semiconductor structure 20, light incident on the first substrate 10 from the third surface 23 of the semiconductor structure 20 is exposed. The light propagating within the first substrate 10 is likely to be totally reflected at the interface between the part 11a of the first surface 11 and the air in the space 90. As a result, the amount of light propagating within the first substrate 10 that passes through the part 11a of the first surface 11 and goes toward the second substrate 50 can be reduced, and the light extraction efficiency from the second surface 12 can be improved. can be done.

Here, in the first substrate 10, the reflectance on the first surface 11 of the first substrate 10 is The first simulation results comparing the two will be explained. Generally, AlN is used as a buffer layer to alleviate lattice mismatch when forming a nitride semiconductor layer on a sapphire substrate.

FIG. 8 is a graph showing the first simulation results. The horizontal axis represents the angle of incidence of light entering the first surface 11 from inside the first substrate 10 to the first surface 11 . The vertical axis represents the reflectance at the first surface 11 of light that enters the first surface 11 from inside the first substrate 10 . Here, the first substrate 10 is a sapphire substrate. Further, here, the wavelength of light was 280 nm. When there is an AlN film on the first surface 11, the reflectance was simulated by changing the thickness of the AlN film to 50 nm, 100 nm, 500 nm, and 1000 nm. In FIG. 8, "No AlN" indicates a case where there is no AlN film on the first surface 11 and the first surface 11 is exposed to air.

From the results shown in FIG. 8, when the first surface 11 is exposed, total reflection occurs at an incident angle of 33° or more. Therefore, when the first surface 11 is exposed, the reflectance is higher than when the first surface 11 has an AlN film at an incident angle of 33 degrees or more.

The light emitted by the active layer 21 is also emitted from the side surface 25 of the semiconductor structure 20 . The light emitted from the side surface 25 of the semiconductor structure 20 enters the first substrate 10 through a portion 11 a of the first surface 11 and can be extracted from the second surface 12 to the outside of the light emitting device 1 . When the AlN film is present on a portion 11a of the first surface 11, light absorption occurs in the AlN film. When there is no AlN film on a part 11a of the first surface 11, compared to a case where there is an AlN film on a part 11a of the first surface 11, the amount of light emitted from the side surface 25 of the semiconductor structure 20 is affected by the first surface 11. The light transmittance can be increased, and the light extraction efficiency from the second surface 12 can be improved.

FIG. 9 shows actual measurements comparing the light transmittance on the first surface 11 of the first substrate 10 when there is an AlN film on the first surface 11 and when there is no AlN film on the first surface 11. It is a graph showing the results. The horizontal axis represents the wavelength of light. The vertical axis represents the light transmittance on the first surface 11. The first substrate 10 is a sapphire substrate. Note that the results shown in FIG. 9 were measured using a spectrophotometer.
In FIG. 9, the solid line represents the results when there is no AlN film on the first surface 11, and the broken line represents the results when the first surface 11 has an AlN film with a thickness of 2 μm.

From the results in FIG. 9, when there is no AlN film on the first surface 11, the light transmittance on the first surface 11 can be made higher than when there is an AlN film with a thickness of 2 μm on the first surface 11. 11 can be reduced.

FIG. 10 is a graph showing the second simulation results. The horizontal axis represents the width in the first direction X of the first region 12-1 on the second surface 12 of the first substrate 10, where the plurality of convex portions 12a are arranged. The vertical axis represents the light extraction efficiency from the second surface 12. The light extraction efficiency indicates how much light emitted from the active layer 21 of the semiconductor structure 20 can be extracted. The wavelength of the light was 280 nm. Further, the first substrate 10 is a sapphire substrate.

In the second simulation, the width of the first surface 11 and second surface 12 of the first substrate 10 in the first direction X is 3000 μm. The center of the first region 12-1 in the first direction X and the center of the third surface 23 of the semiconductor structure 20 in the first direction X are the centers of the first surface 11 and the second surface 12 in the first direction It is matched. The width of the third surface 23 of the semiconductor structure 20 in the first direction X is 1000 μm. Therefore, when the width of the first region 12-1 is 1000 μm, it means that the convex portion 12a is arranged only on the second surface 12 that overlaps the semiconductor structure 20 of the second surface 12 in a top view, and This represents a case where the second surface 12 does not exist in an area outside the outer edge 23a of the third surface 23. When the width of the first region 12-1 is 3000 μm, it means that the convex portion 12a is located on the entire surface of the second surface 12. For example, in FIG. 1, the width of the first region 12-1 is 1500 μm, which means that the width of the semiconductor structure 20 is 1000 μm in the first direction X, and the outer edge 23a of the third surface 23 of the semiconductor structure 20, This is a case where the width between two boundaries 15 located on both sides of the semiconductor structure 20 is 250 μm.

From the results shown in FIG. 10, it is preferable that the width of the first region 12-1 is at least larger than the width of the semiconductor structure 20 when viewed from above. Furthermore, it is more preferable that the width of the first region 12-1 is greater than 1000 μm. In a top view, by arranging the convex portions 12a also in a region of the second surface 12 outside the outer edge 23a of the third surface 23 of the semiconductor structure 20, the convex portions 12a are located on the second surface 12 of the semiconductor structure. The light extraction efficiency can be further improved than when disposing only on the second surface 12 that overlaps with the second surface 20. More preferably, the width of the first region 12-1 is 1500 μm or more. Thereby, in the first direction X, the distance from the outer edge 23a of the third surface 23 of the semiconductor structure 20 to the boundary 15 can be increased. The light totally reflected by the second region 12-2 of the second surface 12 of the first substrate 10 returns toward the first surface 11 of the first substrate 10. By increasing the distance from the outer edge 23a of the third surface 23 to the boundary 15, absorption of light returning toward the first surface 11 of the first substrate 10 by the semiconductor structure 20 can be reduced. Therefore, the light extraction efficiency of the light emitting device 1 can be improved.

Further, from the results shown in FIG. 10, when the width of the first region 12-1 becomes 2000 μm or more, there is no significant change in the light extraction efficiency. Light propagating within the first substrate 10 to a region outside the outer edge 23a of the third surface 23 of the semiconductor structure 20 may be reflected by the second surface 12 and enter the first surface 11. If the entire surface of the second surface 12 is the first region 12-1 having the convex portions 12a, the convex portions 12a of the second surface 12 in the region outside the outer edge 23a of the third surface 23 of the semiconductor structure 20. Due to the diffuse reflection of the light, light that is incident on the first surface 11 at an incident angle smaller than the critical angle is likely to occur. That is, when the entire surface of the second surface 12 is the first region 12-1 having the convex portion 12a, the light is not transmitted to the first surface 11 in the region outside the outer edge 23a of the third surface 23 of the semiconductor structure 20. Total reflection becomes difficult, the amount of transmitted light from the first surface 11 to the space 90 increases, and this transmitted light is easily absorbed by the second substrate 50 and the second bonding member 42 . Therefore, the boundary 15 between the first region 12-1 and the second region 12-2 is preferably located inside the inner edge 32a of the metal member 32 (on the semiconductor structure 20 side). The width of the first region 12-1 is preferably 2000 μm or less with respect to the third surface 23 of the semiconductor structure 20, which has a width of 1000 μm.
The width of the first region 12-1 is preferably at least larger than the width of the semiconductor structure 20 and smaller than the width of the second surface 12 (3000 μm in the second simulation). Thereby, light extraction efficiency can be improved. Further, the width of the first region 12-1 is more preferably 1500 μm or more and 2000 μm or less. Thereby, the light extraction efficiency can be improved while reducing the diffuse reflection of light emitted from the semiconductor structure 20.

It is preferable that the surface roughness of the second region 12-2 is smaller than that of the first region 12-1. Making the surface roughness of the second region 12-2 smaller than the surface roughness of the first region 12-1 includes not arranging a convex portion in the second region 12-2. By making the surface roughness of the second region 12-2 smaller than the surface roughness of the first region 12-1, the light emitting device 1 reduces the diffuse reflection of light emitted from the semiconductor structure 20 by the convex portions 12a. However, the light propagating within the first substrate 10 can be easily totally reflected on the first surface 11, and the light extraction efficiency from the second surface 12 can be improved.

For example, in the first direction 12-2 in the first direction X) is preferably 10% or more and 20% or less of the shortest distance between the outer edges 12b of the second surface 12 (3000 μm in the second simulation). Thereby, it is possible to reduce the light incident on the metal member 32 due to diffuse reflection by the convex portion 12a while improving the light extraction efficiency by the convex portion 12a.

Further, for example, in the first direction It is preferable that the position be located at a point that is 25% or more and 50% or less of the shortest distance between the outer edges 23a (1000 μm in the second simulation). Thereby, it is possible to reduce the light incident on the metal member 32 due to diffuse reflection by the convex portion 12a while improving the light extraction efficiency by the convex portion 12a.

When the width of the third surface 23 of the semiconductor structure 20 becomes smaller than the width of the second surface 12 of the first substrate 10 in the first direction It can be made larger than the width of the third surface 23 of the body 20. For example, the shortest distance between the outer edge 23a of the third surface 23 of the semiconductor structure 20 and the inner edge 32a of the metal member 32 in the first direction ) is preferably 10% or more and 20% or less of the shortest distance between the outer edges 12b of the second surface 12 of the first substrate 10. Thereby, light emitted from the side surface 25 of the semiconductor structure 20 is easily extracted to the outside of the light emitting device 1 by the convex portion 12a of the first region 12-1.

Next, an example of a method for manufacturing the light emitting device 1 of the first embodiment will be described with reference to FIGS. 3A to 3D.
3A to 3D are cross-sectional views for explaining one step of the method for manufacturing the light emitting device 1 of the first embodiment.

As shown in FIG. 3A, the method for manufacturing the light emitting device 1 includes the step of preparing a wafer W having a first substrate 10 and a semiconductor structure 20'. The semiconductor structure 20' has the same structure as the semiconductor structure 20, and the semiconductor structure 20 is obtained by removing a portion of the semiconductor structure 20' as described later. The semiconductor structure 20' can be formed on the first surface 11 of the first substrate 10 by, for example, MOCVD. For example, the semiconductor structure 20' includes, in order from the first surface 11 side of the first substrate 10, an n-side layer, an active layer 21, and a p-side layer. For example, the semiconductor structure 20' having a thickness of 6 μm can be formed on the first substrate 10 having a thickness of 850 μm. By using the first substrate 10 having a thickness of 750 μm or more, warpage of the first substrate 10 can be reduced.

It is preferable to form a first region 12-1 having a plurality of convex portions 12a on the second surface 12 of the first substrate 10 before forming the semiconductor structure 20'. A step of forming a plurality of convex portions 12a on the second surface 12 of the first substrate 10 may be performed before a step of cutting the first substrate 10, which will be described later, and after a step of polishing the first substrate 10. The area other than the first area 12-1 on the second surface 12 of the first substrate 10 becomes a second area 12-2 whose surface roughness is smaller than that of the first area 12-1. The step of preparing the wafer W includes the step of removing the active layer 21 and a portion of the p-side layer so that a portion of the n-side layer of the semiconductor structure 20' is exposed. Further, in the step of preparing the wafer W, the electrode 31 can be placed on the fourth surface 24 of the semiconductor structure 20'. The electrode 31 can be arranged to be electrically connected to each of the n-side layer and the p-side layer.

The method for manufacturing the light emitting device 1 includes a step of preparing the wafer W and then removing a portion of the semiconductor structure 20'. By removing a portion of the semiconductor structure 20', as shown in FIG. 3B, the semiconductor structure 20 is left on the first surface 11 of the first substrate 10, and a portion 11a of the first surface 11 is removed as a semiconductor. exposed from the structure 20. For example, a portion of the semiconductor structure 20 can be removed by RIE (Reactive Ion Etching).

The method for manufacturing the light emitting device 1 includes exposing a part 11a of the first surface 11 of the first substrate 10, and then exposing the second region 12-2 of the second surface 12 of the first substrate 10, as shown in FIG. 3C. A step of forming a metal member 32 on a part of the first surface 11 overlapping with the semiconductor structure 20 in the first direction X is provided. The metal member 32 is preferably formed apart from the outer edge 12b of the second surface 12 of the first substrate 10. Alternatively, the shortest distance between the outer edge of the metal member 32 (the edge opposite to the inner edge 32a of the metal member 32 in the first direction X) and the outer edge 12b of the second surface 12 of the first substrate 10 is It may be 10% or less of the shortest distance between the outer edges 12b of the second surface 12 of the substrate 10. This makes it easy to cut the first substrate 10 in the step of cutting the first substrate 10, which will be described later. Furthermore, it is more preferable that the outer edge of the metal member 32 be formed at a distance of 10 μm or more and 20 μm or less from the outer edge 12 b of the second surface 12 of the first substrate 10 . Thereby, the yield can be further improved in the step of cutting the first substrate 10, which will be described later. Note that the electrode 31 may be placed on the fourth surface 24 of the semiconductor structure 20 after exposing the part 11a of the first surface 11 of the first substrate 10. In this case, the electrode 31 and the metal member 32 can be formed from the same material at the same time. Thereby, the process can be simplified. Note that the step of forming the metal member 32 may be performed after the step of cutting the first substrate 10, which will be described later.

The method for manufacturing the light emitting device 1 includes a step of irradiating the second region 12-2 of the first substrate 10 with a laser beam and cutting the first substrate 10. The laser light is irradiated onto the second region 12-2 from the second surface 12 side located on the opposite side of the first surface 11 where the semiconductor structure 20 is disposed. This makes the semiconductor structure 20 less susceptible to damage by laser light.

The first substrate 10 is cut along the first direction X and the second direction Y. After cutting the first substrate 10, the side surface 10a of the first substrate 10 is exposed at the cutting position X1 of the first substrate 10, as shown in FIG. 3D. In the first direction X, the metal member 32 is located between the cutting position X1 of the first substrate 10 and the semiconductor structure 20. Also in the second direction Y, the metal member 32 is located between the cutting position of the first substrate 10 and the semiconductor structure 20.

The laser light is focused by a lens and irradiated inside the first substrate 10 . When the laser beam is irradiated from the second surface 12 side, the laser beam is scattered by the convex portions 12a, which may make it difficult to cut the first substrate 10 or result in defective cutting. For example, when using the first substrate 10 with a thickness of 850 μm, the convergence area of the laser beam required to cut the first substrate 10 is 467 μm from the optical axis of the lens. Therefore, for example, in the first direction The distance between the outer edges 12b of the two surfaces 12 is preferably 10% or more and 20% or less. Thereby, the first substrate 10 can be cut well with the laser beam.

Note that when performing the step of forming the metal member 32 after cutting the first substrate 10, by increasing the distance between the part 11a of the first surface 11 and the outer edge 23a of the third surface 23 of the semiconductor structure 20, The first substrate 10 can also be cut by irradiating the first substrate 10 with laser light from the first surface 11 side where the semiconductor structure 20 is disposed. In this case, the shortest distance between the outer edge 23a of the third surface 23 of the semiconductor structure 20 and the inner edge 32a of the metal member 32 in the first direction By setting the shortest distance between them to be 10% or more and 20% or less, the semiconductor structure 20 can be made less susceptible to damage by the laser beam even if the laser beam is irradiated from the first surface 11 side. Further, a step of polishing the first substrate 10 may be performed. When performing the step of polishing the first substrate 10, the step of forming the plurality of convex portions 12a on the second surface 12 of the first substrate 10 involves polishing the semiconductor structure 20' on the first surface 11 of the first substrate 10. Preferably, this is done after formation. By polishing the first substrate 10, the light emitting device 1 can be downsized.

In the method for manufacturing the light emitting device 1, after the step of cutting the first substrate 10, as shown in FIG. The method includes a step of joining the first substrate 10 and the second substrate 50 so as to face each other. A first bonding member 41 electrically connected to the electrode 31 is formed between the electrode 31 and the second substrate 50, and a second bonding member 42 is formed between the metal member 32 and the second substrate 50. Then, the first substrate 10 and the second substrate 50 are bonded.

For example, a second substrate 50 on which wirings 51 and 52 are formed is prepared. Thereafter, the first bonding member 41 is placed on the wiring 51 of the prepared second substrate 50, and the second bonding member 42 is placed on the wiring 52. The thickness of the first joining member 41 and the second joining member 42 is, for example, 30 μm or more and 150 μm or less. The second substrate 50 on which the first bonding member 41 and the second bonding member 42 are disposed is opposed to the first substrate 10, the electrode 31 is placed on the first bonding member 41, and the metal is placed on the second bonding member 42. Place the member 32. Thereafter, the first joining member 41 and the second joining member 42 are heated and melted to join the first joining member 41 and the electrode 31, and to join the second joining member 42 and the metal member 32. For example, eutectic bonding or the like can be used to bond the first bonding member 41 and the electrode 31 and to bond the second bonding member 42 and the metal member 32.

[Second embodiment]
FIG. 4 is a cross-sectional view of the light emitting device 2 of the second embodiment.

The light emitting device 2 of the second embodiment further includes a protective film 60 in addition to the configuration of the light emitting device 1 of the first embodiment. The protective film 60 covers the surface (fourth surface 24 and side surface 25) of the semiconductor structure 20. Thereby, oxidation of the semiconductor structure 20 can be reduced. The protective film 60 is an insulating film. For example, a silicon oxide film can be used as the protective film 60.

The protective film 60 also covers a portion 11a of the first surface 11 of the first substrate 10 located outside the outer edge 23a of the third surface 23 of the semiconductor structure 20. The protective film 60 can cover the entire part 11a of the first surface 11.

Further, in the first direction X, the part 11a of the first surface 11 has a region exposed from the protective film 60 between the outer edge 16 of the first region 12-1 and the inner edge 32a of the metal member 32. The outer edge 16 of the first region 12-1 coincides with the boundary 15 between the first region 12-1 and the second region 12-2. By not disposing the protective film 60 between the metal member 32 and the first surface 11, the bonding strength between the first surface 11 and the metal member 32 can be increased.

Furthermore, by exposing a portion 11a of the first surface 11 from the protective film 60, light that enters the first substrate 10 from the third surface 23 of the semiconductor structure 20 and propagates within the first substrate 10 can be Total reflection is likely to occur at the interface between the part 11a of the first surface 11 and the air in the space 90. As a result, the amount of light propagating within the first substrate 10 that passes through the part 11a of the first surface 11 and goes toward the second substrate 50 can be reduced, and the light extraction efficiency from the second surface 12 can be improved. can be done.

Furthermore, in the region where the protective film 60 is not present on the part 11a of the first surface 11, the transmittance of light emitted from the side surface 25 of the semiconductor structure 20 can be increased, and the efficiency of light extraction from the second surface 12 can be improved. I can do it.

FIG. 11 is a graph showing the third simulation results. The horizontal axis represents the width of the protective film 60 in the first direction X. The vertical axis represents the light extraction efficiency from the second surface 12. The light extraction efficiency indicates how much light emitted from the active layer 21 of the semiconductor structure 20 can be extracted. The thickness of the protective film 60 disposed on the first substrate 10 was 1300 nm. The wavelength of the light was 280 nm. The first substrate 10 is a sapphire substrate.

In the third simulation, the width of the first surface 11 and second surface 12 of the first substrate 10 in the first direction X is 3000 μm. The center of the first region 12-1 in the first direction X and the center of the third surface 23 of the semiconductor structure 20 in the first direction X are the centers of the first surface 11 and the second surface 12 in the first direction It is matched. The width in the first direction X of the first region 12-1 having the plurality of convex portions 12a is 2000 μm. The width of the third surface 23 of the semiconductor structure 20 in the first direction X is 1000 μm. Therefore, the width of the protective film 60 of 1000 μm represents the case where the protective film 60 is not disposed on the first surface 11. The width of the protective film 60 of 2000 μm means that the outer edge of the protective film 60 is located at the outer edge 16 of the first region 12-1. The width of the protective film 60 of 3000 μm means that the protective film 60 is present on the entire surface of the semiconductor structure 20 and the part 11a of the first surface 11.

From the results shown in FIG. 11, it is preferable that the width of the protective film 60 is approximately 2000 μm. Thus, in the first direction X, the first surface 11 of the first substrate 10 is exposed from the protective film 60 between the outer edge 16 of the first region 12-1 and the inner edge 32a of the metal member 32. . That is, by making the width of the protective film 60 approximately the same as the width of the first region 12-1, the light extraction efficiency can be improved.

[Third embodiment]
FIG. 5 is a cross-sectional view of the light emitting device 3 of the third embodiment.

The light emitting device 3 of the third embodiment further includes a Zener diode 70 in addition to the configuration of the light emitting device 1 of the first embodiment. Further, the light emitting device 3 of the third embodiment may include the protective film 60 of the second embodiment.

Zener diode 70 may be formed from a portion of semiconductor structure 20' in wafer W shown in FIG. 3A. That is, when removing a portion of the semiconductor structure 20', the Zener diode 70 can be left on the first surface 11 of the first substrate 10 together with the semiconductor structure 20.

The Zener diode 70 is arranged on the first surface 11 between the outer edge 23 a of the third surface 23 of the semiconductor structure 20 and the inner edge 32 a of the metal member 32 . An electrode 71 is arranged on a surface of the Zener diode 70 located on the opposite side of the surface facing the first surface 11 . Electrode 71 is electrically connected to Zener diode 70 . A third bonding member 72 bonded to the electrode 71 is arranged between the electrode 71 and the second substrate 50 . The third bonding member 72 is electrically connected to the wiring 51 arranged on the surface of the second substrate 50. The Zener diode 70 is electrically connected to the wiring 51 arranged on the surface of the second substrate 50 via an electrode 71 and a third bonding member 72. Furthermore, the Zener diode 70 is electrically connected to the semiconductor structure 20 via a wiring 51 arranged on the surface of the second substrate 50.

[Fourth embodiment]
FIG. 6 is a cross-sectional view of the light emitting device 4 of the fourth embodiment. FIG. 7 is a top view of the light emitting device 4 of the fourth embodiment. FIG. 6 is a sectional view taken along line VI-VI in FIG. 7.

The light emitting device 4 of the fourth embodiment includes a plurality of semiconductor structures 20 arranged on the first surface 11 of the first substrate 10. As shown in FIG. 7, the plurality of semiconductor structures 20 are spaced apart from each other in the first direction X and the second direction Y. The light emitting device 4 of the fourth embodiment has basically the same structure as the light emitting device 1 of the first embodiment except that the number of semiconductor structures 20 is different. In the light emitting device 4 of the fourth embodiment, the "outer edge 23a of the third surface 23" is the outer edge 23a of the third surface 23 of the semiconductor structure 20 located at the outermost side in the first direction X (or the second direction Y). represents.

The light emitting device 4 of the fourth embodiment can include the protective film 60 of the second embodiment and the Zener diode 70 of the third embodiment.

In the light emitting devices 1 to 4 described above, an optical film can be disposed on the second surface 12 of the first substrate 10. Thereby, reflection on the second surface 12 can be reduced and the light extraction efficiency from the second surface 12 can be improved. As the optical film, for example, a SiO ₂ film, a MgF ₂ film, or a HfO film can be used. Further, as the optical film, a laminated film including two or more of the above-mentioned films can be used.

The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. All forms that can be implemented by appropriately modifying the design based on the above-described embodiments of the present invention by those skilled in the art also belong to the scope of the present invention as long as they encompass the gist of the present invention. In addition, those skilled in the art will be able to come up with various changes and modifications within the scope of the present invention, and these changes and modifications also fall within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1-4... Light emitting device, 10... First substrate, 11... First surface, 12... Second surface, 12b... Outer edge of second surface, 12-1... First region, 12-2... Second region, 12a ...Convex portion, 20...Semiconductor structure, 21...Active layer, 23...Third surface, 23a...Outer edge of third surface, 24...Fourth surface, 31...Electrode, 32...Metal member, 32a...Inner edge of metal member , 41... First bonding member, 42... Second bonding member, 50... Second substrate, 51, 52... Wiring, 60... Protective film, 70... Zener diode

Claims (8)

a first substrate that is translucent and has a first surface and a second surface located on the opposite side of the first surface;
The third surface is disposed on a part of the first surface of the first substrate, and has a third surface opposite to the first surface of the first substrate, and a fourth surface located on the opposite side of the third surface. , a semiconductor structure including an active layer;
an electrode disposed on the fourth surface of the semiconductor structure and electrically connected to the semiconductor structure;
a metal member disposed on the first surface of the first substrate and spaced apart from the semiconductor structure in a first direction parallel to the first surface of the first substrate;
a second substrate facing the first surface of the first substrate and the fourth surface of the semiconductor structure;
a first bonding member disposed between the second substrate and the electrode and electrically connected to the electrode;
a second joining member disposed between the second substrate and the metal member and joined to the metal member;
Equipped with
The second surface of the first substrate has a plurality of convex portions, and includes a first region of the second surface that overlaps at least the third surface when viewed from above, and a first region and the third surface of the second surface. a second region located between the outer edge of the second surface and having a surface roughness smaller than that of the first region;
In the light emitting device, in the first direction, a boundary between the first region and the second region is located between an outer edge of the third surface of the semiconductor structure and an inner edge of the metal member. 2. The shortest distance between the third surface and the inner edge of the metal member in the first direction is 10% or more and 20% or less of the shortest distance between the outer edges of the second surface. light emitting device. 3. The light emitting device according to claim 1, wherein the second bonding member continuously surrounds the semiconductor structure when viewed from above. 4. The shortest distance between the outer edge of the second surface and the boundary in the first direction is 10% or more and 20% or less of the shortest distance between the outer edges of the second surface. The light emitting device according to any one of the above. In the first direction, the boundary is located at a point where a distance from the outer edge of the third surface is 25% or more and 50% or less of the shortest distance between the outer edges of the third surface. 4. The light emitting device according to any one of 4. 6. The light emitting device according to claim 1, wherein the active layer emits light having a peak wavelength of 400 nm or less. further comprising a protective film covering a surface of the semiconductor structure and the first surface of the first substrate,
7. In a top view, the first surface of the first substrate is exposed from the protective film between the outer edge of the first region and the inner edge of the metal member. The light emitting device described in . A first substrate having a first surface and a second surface located on the opposite side of the first surface, wherein the second surface has a first region having a plurality of convex portions and a second surface located on the opposite side of the first surface. the first substrate having a second region having a small surface roughness; a third surface disposed on the first surface and facing the first surface; and a fourth surface located on the opposite side of the third surface. preparing a wafer having a semiconductor structure having a surface;
removing a portion of the semiconductor structure to expose a portion of the first surface from the semiconductor structure;
forming an electrode on the fourth surface of the semiconductor structure;
forming a metal member on a part of the first surface overlapping the second region of the second surface, spaced apart from the semiconductor structure in a first direction parallel to the first surface;
The step of cleaving the first substrate by irradiating the second region of the first substrate with a laser beam, wherein the metal member is aligned with the cutting position of the first substrate and the semiconductor structure in the first direction. A process located between the body and
a first junction that is electrically connected to the electrode between the electrode and the second substrate, with the first surface of the first substrate and the fourth surface of the semiconductor structure facing a second substrate; joining the first substrate and the second substrate by forming a member and forming a second joining member between the metal member and the second substrate;
A method of manufacturing a light emitting device comprising:

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