Semiconductor light emitting device and method for manufacturing same

According to one embodiment, a semiconductor light emitting device includes: a stacked body, a wavelength conversion layer, a first metal layer, and a first insulating section. The stacked body includes: a first and a second semiconductor layers; and a first light emitting layer provided between the first and the second semiconductor layers. The wavelength conversion layer is configured to convert wavelength of light emitted from the first light emitting layer. The first semiconductor layer is placed between the first light emitting layer and the wavelength conversion layer. The first metal layer is electrically connected to the second semiconductor layer. The first insulating section is provided between a first side surface and a first side surface portion of the first metal layer and between the wavelength conversion layer and the first side surface portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2012-256725, filed on Nov. 22, 2012; the entire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a semiconductor light emitting device and method for manufacturing same.

BACKGROUND

Semiconductor light emitting devices such as light emitting diodes and laser diodes are known. In semiconductor light emitting devices, improvement of heat dissipation is desired. For instance, due to heat generation, the resistance of the semiconductor crystal around the electrode may be decreased and locally form a path where the current easily flows. In this case, for instance, the decrease of light emission uniformity and the crystal degradation are more likely to occur. Furthermore, in a semiconductor light emitting device including a wavelength conversion layer made of e.g. phosphor, the temperature increase of the wavelength conversion layer may change the characteristics of the wavelength conversion layer.

DETAILED DESCRIPTION

In general, according to one embodiment, a semiconductor light emitting device includes: a stacked body including: a first semiconductor layer of a first conductivity type; a second semiconductor layer of a second conductivity type spaced from the first semiconductor layer in a first direction; and a first light emitting layer provided between the first semiconductor layer and the second semiconductor layer, the first semiconductor layer having a first side surface non-parallel to a plane perpendicular to the first direction; a wavelength conversion layer configured to convert wavelength of light emitted from the first light emitting layer, the first semiconductor layer being placed between the first light emitting layer and the wavelength conversion layer; a first metal layer including: a first side surface portion opposed to at least part of the wavelength conversion layer, and the first side surface; and a first bottom surface portion opposed to the second semiconductor layer, the first metal layer being electrically connected to the second semiconductor layer; and a first insulating section provided between the first side surface and the first side surface portion and between the wavelength conversion layer and the first side surface portion, and electrically insulating between the first semiconductor layer and the first metal layer.

In general, according to another embodiment, a method for manufacturing a semiconductor light emitting device is provided. The method includes: preparing a workpiece including: a substrate; and a stacked film stacked on the substrate in a first direction and including: a first semiconductor film of a first conductivity type; a second semiconductor film of a second conductivity type, the first semiconductor film being placed between the substrate and the second semiconductor film; and a light emitting film provided between the first semiconductor film and the second semiconductor film; forming in the workpiece a trench exposing a first side surface non-parallel to a plane perpendicular to the first direction of the first semiconductor film by removing part of the second semiconductor film, part of the light emitting film, and part of the first semiconductor film; forming an insulating film on the workpiece provided with the trench; forming on the insulating film a metal film including a bottom surface portion opposed to the second semiconductor film and a side surface portion opposed to the first side surface by depositing a metal material on the insulating film to fill the trench with the metal material; removing the substrate to expose a stacked body including: a first semiconductor layer formed from the first semiconductor film and having the first side surface; a light emitting layer formed from the light emitting film; and a second semiconductor layer formed from the second semiconductor film; and forming on the stacked body a wavelength conversion layer, at least part of the wavelength conversion layer being opposed to the side surface portion.

Embodiments will now be described with reference to the drawings.

The drawings are schematic or conceptual. The relationship between the thickness and the width of each portion, and the size ratio between the portions, for instance, are not necessarily identical to those in reality. Furthermore, the same portion may be shown with different dimensions or ratios depending on the figures.

In the present specification and the drawings, components similar to those described previously with reference to earlier figures are labeled with like reference numerals, and the detailed description thereof is omitted appropriately.

FIGS. 1A and 1Bare schematic views showing a semiconductor light emitting device according to a first embodiment.

FIG. 1Ais a schematic plan view.FIG. 1Bis a schematic sectional view showing a cross section taken along line A1-A2ofFIG. 1A.

As shown inFIGS. 1A and 1B, the semiconductor light emitting device110according to this embodiment includes a stacked body SB, a wavelength conversion layer40, a metal layer50(first metal layer), and a first insulating section61. InFIG. 1B, for visual clarity of the configuration of each portion such as the stacked body SB, the dimension of each portion is changed fromFIG. 1Afor convenience.

The stacked body SB includes a first semiconductor layer10, a second semiconductor layer20, and a light emitting layer30(first light emitting layer). The first semiconductor layer10has a first side surface51.

The first semiconductor layer10includes a nitride semiconductor and is of the first conductivity type. For instance, the first conductivity type is n-type, and the second conductivity type is p-type. Alternatively, the first conductivity type may be p-type, and the second conductivity type may be n-type. In the following description, it is assumed that the first conductivity type is n-type, and the second conductivity type is p-type. The first semiconductor layer10is e.g. a GaN layer containing n-type impurity. The n-type impurity is e.g. Si.

The second semiconductor layer20is spaced from the first semiconductor layer10in a first direction. In this example, the first direction is set to the Z-axis direction. The first direction is the direction perpendicular to the film surface of the first semiconductor layer10. One direction perpendicular to the Z-axis direction is referred to as X-axis direction. The direction perpendicular to the Z-axis direction and the X-axis direction is referred to as Y-axis direction. The first side surface51is non-parallel to the plane (X-Y plane) perpendicular to the first direction.

The second semiconductor layer20includes a nitride semiconductor and is of the second conductivity type. The second semiconductor layer20is e.g. a GaN layer containing p-type impurity. The p-type impurity is e.g. Mg. The thickness of the second semiconductor layer20is e.g. thinner than the thickness of the first semiconductor layer10. Alternatively, the thickness of the second semiconductor layer20may be more than or equal to the thickness of the first semiconductor layer10.

The light emitting layer30is provided between the first semiconductor layer10and the second semiconductor layer20. The Z-axis direction (first direction) corresponds to e.g. the stacking direction of the first semiconductor layer10, the second semiconductor layer20, and the light emitting layer30.

The light emitting layer30includes e.g. a nitride semiconductor. The light emitting layer30includes e.g. a plurality of barrier layers and well layers provided between the plurality of barrier layers. The barrier layers and the well layers are stacked along the Z-axis direction. The light emitting layer30is based on e.g. an MQW (multi-quantum well) structure. Alternatively, the light emitting layer30may be based on an SQW (single-quantum well) structure. The barrier layer is e.g. a GaN layer. The well layer is e.g. an InGaN layer.

A voltage is applied between the first semiconductor layer10and the second semiconductor layer20to pass a current in the light emitting layer30. Thus, light is emitted from the light emitting layer30.

The wavelength conversion layer40converts the wavelength of light emitted from the light emitting layer30. The wavelength conversion layer40e.g. absorbs at least part of first light emitted from the light emitting layer30, and emits second light of a peak wavelength different from the peak wavelength of the first light. That is, the wavelength conversion layer40converts the peak wavelength of the light emitted from the light emitting layer30. The wavelength conversion layer40may emit e.g. light of a plurality of peak wavelengths different from the peak wavelength of the first light. The wavelength conversion layer40is e.g. a phosphor layer. The wavelength conversion layer40may be e.g. a stacked body of a plurality of phosphor layers different in the peak wavelength of the light emitted therefrom. The wavelength conversion layer40is made of e.g. phosphor-containing ceramic or phosphor-containing transparent resin.

The emission light of the light emitting layer30is e.g. red light, yellow light, green light, blue light, violet light, or ultraviolet light. The light emitted from the wavelength conversion layer40is e.g. red light, yellow light, green light, blue light, violet light, or ultraviolet light. The combined light of the light emitted from the wavelength conversion layer40and the emission light is e.g. substantially white light. Alternatively, the combined light may be e.g. red light, yellow light, green light, blue light, violet light, or ultraviolet light. The peak wavelength of the combined light may be e.g. an arbitrary wavelength between the infrared region and the ultraviolet region.

At least part of the wavelength conversion layer40is in contact with e.g. the first semiconductor layer10. In this example, the surface10sof the first semiconductor layer10opposed to the wavelength conversion layer40constitutes a light extraction surface. The surface10sis provided with unevenness10v. The surface10sis roughened. This suppresses total reflection at the surface10sof the light emitted from the light emitting layer30, and can increase the light extraction efficiency.

The metal layer50includes a first side surface portion71sand a first bottom surface portion71b. The first side surface portion71sis opposed to at least part of the wavelength conversion layer40, and the first side surface S1. The first bottom surface portion71bis opposed to the second semiconductor layer20. The metal layer50is electrically connected to e.g. the second semiconductor layer20. The absolute value of the difference between the length L1along the Z-axis direction of the first side surface portion71sand the thickness t1(length along the Z-axis direction) of the stacked body SB is e.g. 0.1 μm or more and 1000 μm or less. The absolute value of the difference between the length L1and the thickness t1is preferably more than or equal to e.g. the grain diameter of the phosphor included in the wavelength conversion layer40.

In this embodiment, the wavelength conversion layer40is provided in a recess formed from the first insulating section61(e.g., first insulating layer81and second insulating layer82) and the surface10sof the first semiconductor layer10. The wavelength conversion layer40may fill e.g. the entirety of the recess. In this case, the thickness of the wavelength conversion layer40is substantially equal to the depth of the recess. The wavelength conversion layer40may fill e.g. part of the recess. In this case, the thickness of the wavelength conversion layer40is thinner than the depth of the recess. The wavelength conversion layer40may include e.g. a portion outside the recess. In this case, the thickness of the wavelength conversion layer40is thicker than the depth of the recess.

The distance D1between the first side surface S1and the first side surface portion71sis preferably less than or equal to e.g. the thickness t1in the Z-axis direction of the stacked body SB. This provides e.g. good heat dissipation. Furthermore, the distance D2between the wavelength conversion layer40and the first side surface portion71sis preferably less than or equal to e.g. the thickness t1in the Z-axis direction of the stacked body SB. The distance D1and the distance D2are e.g. a distance in a direction perpendicular to the Z-axis direction. In this example, they are e.g. the distance in the X-axis direction. Alternatively, the distance D1and the distance D2may be e.g. a distance in the direction perpendicular to the surface of the first side surface portion71s. The distance D1and the distance D2are e.g. 10 μm or less. More preferably, the distance D1and the distance D2are e.g. 1 μm or less. This can provide e.g. good heat dissipation. Moreover, for instance, this can suppress cracking of the first insulating section61provided between the first side surface S1and the first side surface portion71s. Furthermore, the distance D1and the distance D2are e.g. 0.1 μm or more. This provides good insulation.

The metal layer50includes e.g. a first layer54and a second layer55. The first layer54is made of e.g. at least one of Ti, W, Pt, Au, Cu, Ni, Ag, Co, Sn, Pd, and Al. The first layer54is made of e.g. an alloy including at least one of Ti, W, Pt, Au, Cu, Ni, Ag, Co, Sn, Pd, and Al. The first layer54functions as e.g. a support metal member for supporting the stacked body SB and the like. The thickness (length along the Z-axis direction) of the first layer54is e.g. 10 μm or more and 1000 μm or less. The surface (bottom surface) of the first layer54on the opposite side from the second layer55is planarized by e.g. grinding processing. This can form a bottom surface facilitating mounting. For instance, the first layer54is made of a material having high thermal conductivity such as Cu and Ni. This can improve e.g. heat dissipation of the stacked body SB (crystal layer).

The second layer55is provided e.g. between the stacked body SB and the first layer54. The second layer55is made of e.g. at least one of Ti, W, Pt, Au, Cu, Ni, Ag, Co, Sn, Pd, and Al. The second layer55is made of e.g. an alloy including at least one of Ti, W, Pt, Au, Cu, Ni, Ag, Co, Sn, Pd, and Al. For instance, the second layer55is made of a metal having high reflectance such as Ag. This can facilitate reflection of light at the first side surface portion71sand further increase the light extraction efficiency. The second layer55functions as an adhesive metal layer for enhancing adhesiveness between the first layer54and the first insulating section61and the like. The metal layer50may be a layer made of one metal material, or a layer made of three or more metal materials.

The metal layer50further includes a first end portion71e. In this example, the first side surface portion71sis placed between the first bottom surface portion71band the first end portion71e. The first end portion71eis spaced from the first bottom surface portion71bas projected on the plane (X-Y plane) perpendicular to the Z-axis direction. The first side surface portion71shas a first opposed surface71fopposed to the first side surface51. The first opposed surface71fis inclined with respect to the Z-axis direction. The angle θs between the opposed surface71fand the X-Y plane is e.g. 10° or more and 60° or less. This can e.g. increase the light extraction efficiency. A more preferable range of the angle θs is e.g. 40° or more and 50° or less. This can e.g. further increase the light extraction efficiency. For instance, the second layer55is made of a metal having high reflectance such as Ag. This can facilitate reflection of light at the first side surface portion71sand further increase the light extraction efficiency.

The first insulating section61is provided between the first side surface S1and the first side surface portion71sand between the wavelength conversion layer40and the first side surface portion71s. The first insulating section61electrically insulates between the first semiconductor layer10and the metal layer50. The first insulating section61covers e.g. the first side surface S1. The first insulating section61covers the side surface of the wavelength conversion layer40. In this example, the first insulating section61includes a first insulating layer81and a second insulating layer82. The first insulating layer81and the second insulating layer82are made of e.g. dielectric. The first insulating layer81and the second insulating layer82are e.g. dielectric films. The dielectric film is e.g. an oxide film or nitride film. The oxide film is e.g. silicon oxide film (e.g., SiO2). The first insulating layer81and the second insulating layer82are formed by e.g. CVD technique or sputtering technique.

In this example, the first insulating section61extends between at least part of the wavelength conversion layer40and the first side surface portion71s. Thus, the first insulating section61is provided between the first side surface S1and the first side surface portion71sand between the wavelength conversion layer40and the first side surface portion71s. The first insulating section61is in contact with e.g. the metal layer50, the first side surface S1, and the wavelength conversion layer40. Thus, for instance, the heat generated in the stacked body SB and the wavelength conversion layer40can be easily released to the metal layer50. The first insulating section61does not necessarily need to be provided between the wavelength conversion layer40and the metal layer50. For instance, the wavelength conversion layer40may be in direct contact with the metal layer50. This can e.g. further improve the heat dissipation. In the case where the first insulating section61is provided between the wavelength conversion layer40and the metal layer50, for instance, the process for manufacturing the semiconductor light emitting device110can be simplified.

The second semiconductor layer20has a side surface20a. The light emitting layer30has a side surface30a. The side surface20aand the side surface30aare non-parallel to the X-Y plane. The side surface30ais continuous with the first side surface S1and the side surface20a. The first insulating section61extends also between the side surface30aand the metal layer50and between the side surface20aand the metal layer50. The first insulating section61electrically insulates e.g. between the light emitting layer30and the metal layer50.

In this example, the semiconductor light emitting device110further includes a first electrode11and a second insulating section62.

The first semiconductor layer10has a first portion10aopposed to the light emitting layer30, and a second portion10bjuxtaposed with the first portion10ain a second direction non-parallel to the Z-axis direction and not opposed to the light emitting layer30. The second portion10bhas a second side surface S2non-parallel to the X-Y plane. The second direction may be an arbitrary direction non-parallel to the Z-axis direction.

The metal layer50further includes a second side surface portion72sand a second bottom surface portion72b. The second side surface portion72sis opposed to at least part of the wavelength conversion layer40, and the second side surface S2. The second bottom surface portion72bis opposed to the second portion10band is continuous with the first bottom surface portion71b.

The distance D3between the second side surface S2and the second side surface portion72sis preferably less than or equal to e.g. the thickness t1in the Z-axis direction of the stacked body SB. This provides e.g. good heat dissipation. Furthermore, the distance D4between the wavelength conversion layer40and the second side surface portion72sis preferably less than or equal to e.g. the thickness t1in the Z-axis direction of the stacked body SB. The distance D3and the distance D4are e.g. a distance in a direction perpendicular to the Z-axis direction. In this example, they are e.g. the distance in the X-axis direction. Alternatively, the distance D3and the distance D4may be e.g. a distance in the direction perpendicular to the surface of the second side surface portion72s. The distance D3and the distance D4are e.g. 10 μm or less. More preferably, the distance D3and the distance D4are e.g. 2 μm or less. This can e.g. further improve the heat dissipation. Furthermore, the distance D3and the distance D4are e.g. 0.1 μm or more. This provides good insulation.

The first electrode11is provided between the second portion10band the second bottom surface portion72b, and electrically connected to the first semiconductor layer10. The first electrode11is in contact with e.g. the second portion10b.

The first electrode11is e.g. reflective to the light emitted from the light emitting layer30. The first electrode11includes e.g. at least one of Ti, Pt, Al, Ag, Ni, Au, and Ta. The first electrode11is made of e.g. an alloy including at least one of Ti, Pt, Al, Ag, Ni, Au, and Ta. More preferably, the first electrode11includes at least one of Al and Ag. Thus, for instance, the first electrode11can be provided with good reflectivity to the light emitted from the light emitting layer30, and the light extraction efficiency can be improved. The thickness of the first electrode11is e.g. 10 nm or more and 10 μm or less. More preferably, in view of the film thickness needed as a reflective film estimated from the plasma frequency and the reduction of operating voltage, the thickness of the first electrode11is 100 nm or more and 1 μm or less.

The second insulating section62is provided between the second side surface S2and the second side surface portion72sand between the wavelength conversion layer40and the second side surface portion72s. The second insulating section62electrically insulates between the first semiconductor layer10and the metal layer50. The second insulating section62covers e.g. the second side surface S2. The second insulating section62covers e.g. the side surface of the wavelength conversion layer40. The second insulating section62is in contact with e.g. the metal layer50, the second side surface S2, and the wavelength conversion layer40. The second insulating section62does not necessarily need to be provided between the wavelength conversion layer40and the metal layer50.

The second insulating section62includes a third insulating layer83(insulating layer), a fourth insulating layer84, and a wiring layer80. The wiring layer80is electrically connected to the first electrode11. The third insulating layer83is provided between the wiring layer80and the metal layer50, and electrically insulates between the wiring layer80and the metal layer50. The fourth insulating layer84is provided e.g. between the first semiconductor layer10and the wiring layer80and between the wavelength conversion layer40and the wiring layer80. In this example, the light emitting layer30has a side surface30bdifferent from the side surface30a. The second semiconductor layer20has a side surface20bdifferent from the side surface20a. The fourth insulating layer84extends between the above side surface30bof the light emitting layer30and the metal layer50and between the above side surface20bof the second semiconductor layer20and the metal layer50. Here, the first insulating layer81and the third insulating layer83may constitute one continuous layer. The second insulating layer82and the fourth insulating layer84may constitute one continuous layer.

The wiring layer80includes e.g. at least one of Ti, Pt, Al, Ag, Ni, Au, and Ta. The wiring layer80is made of e.g. an alloy including at least one of Ti, Pt, Al, Ag, Ni, Au, and Ta. More preferably, the wiring layer80includes at least one of Al and Ag. Thus, for instance, the wiring layer80can be provided with good reflectivity to the light emitted from the light emitting layer30, and the light extraction efficiency can be improved. The thickness of the wiring layer80is e.g. 10 nm or more and 10 μm or less. More preferably, in view of suppression of step discontinuity and covering with the third insulating layer83, the thickness of the wiring layer80is 600 nm or more and 1 μm or less.

In this example, the semiconductor light emitting device110further includes a third electrode13.

The metal layer50further includes a second end portion72e. In this example, the second side surface portion72sis placed between the second bottom surface portion72band the second end portion72e. The third electrode13is opposed to the second end portion72ein the Z-axis direction. The second insulating section62extends between the second end portion72eand the third electrode13. The wiring layer80is electrically connected to the third electrode13. Thus, the first electrode11is electrically connected to the third electrode13through the wiring layer80. The third electrode13is e.g. a pad electrode used for external wiring. The third electrode13is made of e.g. a metal of at least one of Ti, Pt, and Au, or an alloy including at least one of these metals.

The second end portion72eis spaced from the second bottom surface portion72bas projected on the X-Y plane. The second side surface portion72shas a second opposed surface72fopposed to the second side surface S2. The second opposed surface72fis inclined with respect to the Z-axis direction. The first side surface portion71sis e.g. continuous with the second side surface portion72s. The first side surface portion71sand the second side surface portion72ssurround the stacked body SB centered on e.g. the Z-axis direction.

The length Lf along a direction (e.g., X-axis direction) perpendicular to the Z-axis direction of the wavelength conversion layer40is e.g. less than or equal to the distance D5along the X-axis direction between the first side surface portion71sand the second side surface portion72s. For instance, preferably, the angle of the inclined surface of the second insulating layer82and the angle of the inclined surface of the fourth insulating layer84are substantially equal to e.g. the angle of the inclined surface of the wavelength conversion layer40. Preferably, the area of the roughened region of the first semiconductor layer10is substantially equal to the area of the region of the wavelength conversion layer40in contact with the first semiconductor layer10. At least the angle of the inclined surface of the wavelength conversion layer40is made steeper than the angle of the inclined surface of the second insulating layer82and the angle of the inclined surface of the fourth insulating layer84. The area of the region of the wavelength conversion layer40in contact with the first semiconductor layer10is made smaller than the area of the roughened region of the first semiconductor layer10. In this case, the wavelength conversion layer40can be in contact with the roughened first semiconductor layer10.

The length Lf of the wavelength conversion layer40is e.g. 50% or more of the distance D5. More preferably, the length Lf of the wavelength conversion layer40is e.g. 75% or more of the distance D5. This can make the emission light of the light emitting layer30incident on the wavelength conversion layer40. More preferably, the length Lf of the wavelength conversion layer40is e.g. substantially equal to the distance D5. This can make the emission light of the light emitting layer30incident on the wavelength conversion layer40more appropriately. Here, the length Lf is e.g. the longest of the lengths along the X-axis direction of the wavelength conversion layer40. In this example, the length Lf is e.g. the length in the X-axis direction of the surface40afacing the opposite side of the wavelength conversion layer40from the first semiconductor layer10. The distance D5is e.g. the longest of the distances along the X-axis direction between the first side surface portion71sand the second side surface portion72s.

The semiconductor light emitting device110further includes a second electrode12. The second electrode12is provided between the second semiconductor layer20and the first bottom surface portion71b, and electrically connected to the second semiconductor layer20and the metal layer50. In this example, the second electrode12is in contact with the second semiconductor layer20and the first bottom surface portion71b. The second electrode12is e.g. reflective to the light emitted from the light emitting layer30. The second electrode12includes e.g. Ag. The second electrode12is made of e.g. at least one of Ag and Ag alloy. Thus, for instance, the second electrode12has good reflectivity. The thickness of the second electrode12is e.g. 10 nm or more and 10 μm or less. More preferably, in view of the film thickness needed as a reflective film estimated from the plasma frequency and the reduction of operating voltage, the thickness of the second electrode12is 100 nm or more and 1 μm or less.

Semiconductor light emitting devices such as LED are used in various products such as general lighting products and display backlights. For price reduction of these products, it is effective to reduce the number of LED chips installed in the product, to downsize the LED chip, and to increase the current injected into the LED chip. In downsizing the LED chip and increasing the current, improvement of the heat dissipation of the chip becomes a challenge. In the case of fabricating white LED, it is also important to suppress non-uniformity of color and to increase the yield of the chip.

In reducing the number of LED chips by downsizing the LED chip or increasing the current, the influence of heat generated inside the stacked body SB (crystal layer) is significant. For instance, due to heat generation, the resistance of the crystal layer around the electrode may be decreased and locally form a path where the current easily flows inside the crystal layer. In this case, the decrease of light emission uniformity and the degradation of the crystal layer are more likely to occur. Thus, heat dissipation from the crystal layer is important.

On the other hand, there is a configuration in which the wavelength of light emission emitted from the crystal layer is converted by a wavelength conversion layer made of e.g. phosphor to obtain a color different from the color (wavelength) of the light emission. Thus, for instance, white light is obtained. In such a configuration, due to the heat generated in the crystal layer, the temperature of the wavelength conversion layer is increased. The temperature increase of the wavelength conversion layer may change the wavelength conversion characteristics, and the desired characteristics may not be obtained. Furthermore, heat is generated also during wavelength conversion in the wavelength conversion layer. In the case where the thermal conductivity of the wavelength conversion layer is low, heat dissipation from the wavelength conversion layer is also important.

Thus, there is demand for a novel structure capable of improving the heat dissipation of the wavelength conversion layer as well as improving heat dissipation in the crystal layer.

In the semiconductor light emitting device110according to this embodiment, the heat dissipation of the crystal layer can be improved, and the heat dissipation of the wavelength conversion layer40can also be improved. In this embodiment, the metal layer50opposed to the bottom surface and the side surface of the stacked body SB is provided. Thus, the heat dissipation of the crystal layer can be improved. Furthermore, the metal layer50is opposed to the wavelength conversion layer40. Thus, the heat dissipation of the wavelength conversion layer40can be improved. For instance, the device itself functions as a package having heat sink capability. In the semiconductor light emitting device110according to this embodiment, good heat dissipation can be obtained.

If the metal layer50is opposed to only the bottom surface and the side surface of the stacked body SB, heat can be dissipated from the crystal layer, but heat dissipation from the wavelength conversion layer40is difficult without the intermediary of the crystal layer.

Furthermore, in the configuration based on the wavelength conversion layer, the color may be made non-uniform. For instance, there exists light emitted out laterally (e.g., in a direction parallel to the X-Y plane) from the side surface of the crystal layer. The light emitted out from the major surface of the crystal layer and the light emitted out from the side surface are different in angle and distance when passing through the wavelength conversion layer. Thus, depending on the outgoing angle, for instance, the ratio of the light emission emitted from the crystal layer to the light converted by the wavelength conversion layer is different. Accordingly, the chromaticity changes with the outgoing angle. For instance, in the case where white light is emitted out from the semiconductor light emitting device, the chromaticity changes with the angle. That is, the color is made non-uniform.

In contrast, in the semiconductor light emitting device110according to this embodiment, the side surface of the crystal layer is covered with the metal layer50. Thus, in the semiconductor light emitting device110, occurrence of laterally extracted light can be suppressed by the metal layer50. Furthermore, the light directed laterally from the side surface of the crystal layer can be reflected by the metal layer50and directed to the wavelength conversion layer40. Thus, the light extraction efficiency can be increased. In this embodiment, the light emitted from the stacked body SB efficiently passes inside the wavelength conversion layer40. Thus, in this embodiment, the change of chromaticity depending on the outgoing angle of light can be suppressed, and the uniformity of color can be improved.

An example of a method for manufacturing the semiconductor light emitting device110according to this embodiment is now described.

FIGS. 2A to 2D,3A to3D,4A to4D, and5A to5C are schematic sectional views showing the method for manufacturing a semiconductor light emitting device according to the first embodiment.

As shown inFIG. 2A, in manufacturing the semiconductor light emitting device110, first, a workpiece110wis prepared. The workpiece110wincludes a substrate5and a stacked film SF. The stacked film SF is stacked on the substrate5in the Z-axis direction. The stacked film SF includes a first semiconductor film10fof the first conductivity type constituting a first semiconductor layer10, a second semiconductor film20fof the second conductivity type constituting a second semiconductor layer20, and a light emitting film30fconstituting a light emitting layer30.

In the workpiece110w, the first semiconductor film10fis placed between the substrate5and the second semiconductor film20f. The light emitting film30fis placed between the first semiconductor film10fand the second semiconductor film20f. The substrate5is e.g. a silicon substrate or sapphire substrate. In this example, the thickness of the first semiconductor film10fis thicker than the first semiconductor layer10.

The preparation of the workpiece110wincludes forming the workpiece110wby e.g. forming a first semiconductor film10fon the substrate5, forming a light emitting film30fon the first semiconductor film10f, and forming a second semiconductor film20fon the light emitting film30f.

As shown inFIG. 2B, for instance, by photolithography processing and etching processing, part of the second semiconductor film20fand part of the light emitting film30fare removed. Thus, part of the first semiconductor film10fis exposed. Furthermore, a second semiconductor layer20is formed from the second semiconductor film20f, and a light emitting layer30is formed from the light emitting film30f.

As shown inFIG. 2C, for instance, by photolithography processing and etching processing, part of the first semiconductor film10fis removed to form a plurality of trenches90(device separation trenches). The trench90exposes a first side surface S1aof the first semiconductor film10f. In this example, the plurality of trenches90expose part of the substrate5. Thus, a first semiconductor layer10is formed from the first semiconductor film10f. Furthermore, by the formation of the plurality of trenches90, a plurality of stacked bodies SB are formed from the stacked film SF. Thus, in this example, the trench90exposes a first side surface S1of the first semiconductor layer10. The etching of the workpiece110wis based on e.g. etching technique such as RIE. Here, the depth (distance in the Z-axis direction) of the trench90is made longer than the thickness t1of the stacked body SB of the semiconductor light emitting device110to be manufactured. This makes it possible to form a metal layer50opposed to at least part of a wavelength conversion layer40.

As shown inFIG. 2D, for instance, by film formation processing, a second insulating film82fconstituting a second insulating layer82is formed on each of the plurality of stacked bodies SB and on part of the substrate5exposed by the trench90.

As shown inFIG. 3A, for instance, by photolithography processing, etching processing, and evaporation technique or sputtering technique, a first electrode11is formed on each of the plurality of stacked bodies SB.

As shown inFIG. 3B, for instance, by photolithography processing, etching processing, and evaporation technique or sputtering technique, a wiring layer80is formed on each of the plurality of stacked bodies SB.

As shown inFIG. 3C, for instance, by film formation processing, a first insulating film81fconstituting a first insulating layer81is formed on each of the plurality of stacked bodies SB.

As shown inFIG. 3D, for instance, by photolithography processing, etching processing, and evaporation technique or sputtering technique, a second electrode12is formed on each of the plurality of stacked bodies SB.

As shown inFIG. 4A, for instance, by evaporation technique or sputtering technique, a conductive film55fconstituting a second layer55of a metal layer50is formed on each of the plurality of stacked bodies SB. The conductive film55f(second layer55) is made of e.g. at least one of Ti, W, Pt, Au, Cu, Ni, Ag, Co, Sn, Pd, and Al. The conductive film55fis made of an alloy including at least one of Ti, W, Pt, Au, Cu, Ni, Ag, Co, Sn, Pd, and Al. By using the above material for the conductive film55f(second layer55), for instance, high adhesiveness can be obtained. For instance, the conductive film55fis made of a metal having high reflectance such as Ag.

This can facilitate reflection of light at the portion opposed to the first side surface S1and further increase the light extraction efficiency.

As shown inFIG. 4B, for instance, by plating processing, a conductive film54fconstituting a first layer54of the metal layer50is formed on each of the plurality of stacked bodies SB.

The conductive film54fincludes e.g. at least one of Ti, W, Pt, Au, Cu, Ni, Ag, Co, Sn, Pd, and Al. The conductive film54fis made of e.g. an alloy including at least one of Ti, W, Pt, Au, Cu, Ni, Ag, Co, Sn, Pd, and Al. Thus, a metal material MM is deposited on the first insulating film81f, and the trench90is filled with the metal material MM. Thus, a metal film50fis formed on the first insulating film81f. This metal film50fincludes a bottom surface portion70bopposed to the second semiconductor layer20(second semiconductor film20f), and a side surface portion70sopposed to the first side surface S1. The side surface portion70ssurrounds the bottom surface portion70bcentered on e.g. the Z-axis direction.

As shown inFIGS. 4C and 4D, the substrate5is removed. The removal of the substrate5can be based on e.g. at least one of grinding processing and etching processing. Thus, the stacked body SB is exposed.

As shown inFIG. 5A, for instance, by etching processing, part of the first semiconductor layer10is removed. That is, the first semiconductor layer10is thinned. Thus, a recess91corresponding to the shape of the side surface portion70sis formed. By this etching, unevenness10vis formed on the surface10sof the first semiconductor layer10.

As shown inFIG. 5B, for instance, by photolithography processing, etching processing, and film formation processing, a third electrode13is formed on each of the plurality of stacked bodies SB. The film formation processing is based on e.g. evaporation technique or sputtering technique.

As shown inFIG. 5C, for instance, a wavelength conversion layer40is formed inside the recess91. The wavelength conversion layer40is formed on each of the plurality of stacked bodies SB. In the formation of the wavelength conversion layer40, for instance, a solid wavelength conversion material92is fitted into the recess91.

Subsequently, the plurality of stacked bodies SB are singulated. Thus, the semiconductor light emitting device110according to this embodiment is completed.

In the case where silicon or the like is used for a growth substrate, the growth substrate is susceptible to thermal stress and stress due to lattice strain. Thus, during crystal growth, dislocations or cracks are likely to occur in the crystal layer. Cracks cause the decrease of manufacturing yield of the semiconductor light emitting device.

Thin-film LED is known. In this LED, for instance, after crystal growth, another support substrate (e.g., silicon support substrate) different from the crystal growth substrate is bonded to the crystal layer, and the crystal growth substrate is removed. In this thin-film LED, due to the influence of e.g. difference in linear expansion coefficient between the support substrate and the crystal layer, cracks are further induced during device fabrication. Cracks generated during device fabrication are cracks generated during the process performed after bonding the support substrate and the crystal layer (e.g., removal of the crystal growth substrate).

As a means for suppressing cracks generated during device fabrication, device separation of the crystal layer into chips is effective.

In the method for manufacturing the semiconductor light emitting device110according to this embodiment, device separation can be performed by forming the trench90. Furthermore, the support substrate can be omitted, and the step of bonding to the support substrate can also be omitted.

Thus, cracks generated during device fabrication can be suppressed.

In the semiconductor light emitting device110according to this embodiment, the metal layer50is formed to a position higher than the light extraction surface of the crystal. This configuration provides high controllability of the shape (e.g., thickness) and the like of the wavelength conversion layer40.

In the example of the method for manufacturing the semiconductor light emitting device110according to this embodiment, the wavelength conversion layer40is fabricated independently of the stacked body SB and inserted into the recess91. For instance, a solid material such as ceramic is shaped in an appropriate shape and size to fabricate a wavelength conversion layer40. This wavelength conversion layer40is put into the internal space of the recess91. As a result of this method, the light generated inside the crystal layer efficiently passes inside the wavelength conversion layer40. Thus, for instance, the change of chromaticity depending on the outgoing angle is suppressed. For instance, the phenomenon of the change of color depending on the viewing angle can be suppressed.

In addition, for instance, the stacked body SB can be supported by the wavelength conversion layer40. In this case, the wavelength conversion layer40is thickened so as to be able to support the stacked body SB. In this configuration, the metal layer50can be thinned. Furthermore, in this configuration, for instance, preferably, the electrode is not formed on the light extraction surface (surface10s).

Instead of phosphor-containing ceramic, the wavelength conversion layer40may be made of phosphor-containing transparent resin. In this case, electrodes and mounting wires may be provided on the light extraction surface.

In forming the wavelength conversion layer40, a liquid wavelength conversion material may be placed inside the recess91and solidified.

As described above, in the semiconductor light emitting device110according to this embodiment, the heat dissipation of the wavelength conversion layer40can be improved while improving the heat dissipation of the crystal layer. Furthermore, the uniformity of color can also be improved.

Furthermore, this embodiment can also suppress generation of cracks during manufacturing. Furthermore, this embodiment can also suppress manufacturing cost. For instance, in the method of bonding the crystal layer and the silicon support substrate using AuSn solder, use of gold results in relatively high manufacturing cost. In contrast, this embodiment can adopt the method of forming the metal layer50by plating technique and the like. Thus, this embodiment can suppress cost relative to e.g. the method of using AuSn solder. Furthermore, in the method of bonding the crystal layer and the silicon support substrate, voids (gaps) are likely to occur between the crystal layer and the silicon support substrate. The void decreases e.g. mechanical strength, and decreases the reliability of the semiconductor light emitting device. In contrast, in the semiconductor light emitting device110according to this embodiment, the metal layer50can be formed by plating technique and the like. Thus, the occurrence of voids is suppressed, and the reliability can be further improved.

In this example, the metal layer50includes the first layer54and the second layer55. The thickness of the first layer54is e.g. 10 μm or more and 1000 μm or less. Forming the first layer54by e.g. evaporation technique or sputtering technique takes time. In contrast, forming the first layer54by plating technique can make the manufacturing time shorter than the case of using e.g. evaporation technique or sputtering technique. Forming the second layer55by e.g. evaporation technique or sputtering technique can further enhance adhesiveness e.g. between the metal layer50and the second electrode12.

In the above example of the manufacturing method, a trench90for exposing part of the substrate5is formed, and a stacked body SB is formed by the formation of the trench90. In this embodiment, the trench90does not need to reach the substrate5. The depth of the trench90is comparable to or longer than the thickness t1of the stacked body SB of the semiconductor light emitting device110to be manufactured.

In the case where the trench90does not reach the substrate5, for instance, in the step of thinning the first semiconductor layer10shown inFIG. 5A, the first semiconductor film10fis divided to form a plurality of stacked bodies SB from the stacked film SF.

FIGS. 6A to 6D,7A to7D,8A to8D, and9A to9C are schematic sectional views showing an alternative method for manufacturing a semiconductor light emitting device according to the first embodiment.

As shown inFIG. 6B, for instance, by photolithography processing and etching processing, part of the first semiconductor film10f, part of the second semiconductor film20f, and part of the light emitting film30fare removed. Thus, part of the first semiconductor film10fis exposed. Furthermore, a second semiconductor layer20is formed from the second semiconductor film20f, and a light emitting layer30is formed from the light emitting film30f.

As shown inFIG. 6C, for instance, by photolithography processing and etching processing, part of the first semiconductor film10fand part of the substrate5are removed to form a plurality of trenches94. Thus, a first semiconductor layer10is formed from the first semiconductor film10f, and a plurality of stacked bodies SB are formed from the stacked film SF. The trench94exposes a first side surface S1of the first semiconductor layer10.

As shown inFIG. 6D, for instance, by film formation processing, a second insulating film82fis formed on each of the plurality of stacked bodies SB and on part of the substrate5exposed by the trench94.

As shown inFIG. 7A, for instance, by photolithography processing, etching processing, and evaporation technique or sputtering technique, a first electrode11is formed on each of the plurality of stacked bodies SB.

As shown inFIG. 7B, for instance, by photolithography processing, etching processing, and evaporation technique or sputtering technique, a wiring layer80is formed on each of the plurality of stacked bodies SB.

As shown inFIG. 7C, for instance, by film formation processing, a first insulating film81fis formed on each of the plurality of stacked bodies SB.

As shown inFIG. 7D, for instance, by photolithography processing, etching processing, and film formation processing (such as evaporation technique and sputtering technique), a second electrode12is formed on each of the plurality of stacked bodies SB.

As shown inFIG. 8A, for instance, by evaporation technique or sputtering technique, a conductive film55fconstituting a second layer55of a metal layer50is formed on each of the plurality of stacked bodies SB.

As shown inFIG. 8B, for instance, by plating processing, a conductive film54fconstituting a first layer54of the metal layer50is formed on each of the plurality of stacked bodies SB. Thus, a metal film50fis formed on the first insulating film81f. The metal film50fincludes a bottom surface portion70bopposed to the second semiconductor layer20, and a side surface portion70sopposed to the first side surface S1.

As shown inFIGS. 8C and 8D, for instance, by at least one of grinding processing and etching processing, the substrate5is removed. Thus, a recess91corresponding to the shape of the side surface portion70sis formed.

As shown inFIG. 9A, for instance, by etching processing, part of the first semiconductor layer10is removed. Thus, unevenness10vis formed on the surface10sof the first semiconductor layer10.

As shown inFIG. 9B, for instance, by photolithography processing, etching processing, and evaporation technique or sputtering technique, a third electrode13is formed on each of the plurality of stacked bodies SB.

As shown inFIG. 9C, for instance, by fitting a wavelength conversion material92into the recess91, a wavelength conversion layer40is formed on each of the plurality of stacked bodies SB.

Subsequently, the plurality of stacked bodies SB are singulated. Thus, the semiconductor light emitting device110according to this embodiment is completed.

As described above, in the method for manufacturing the semiconductor light emitting device110, a trench94removing part of the first semiconductor film10fand part of the substrate5may be formed. In this manufacturing method, for instance, unevenness is likely to be formed on the surface of the trench94by etching. As a result, unevenness is formed also on the surface of the second insulating film82fin contact with the trench94. This enhances adhesiveness e.g. at the contact portion between the second insulating film82fand the wavelength conversion layer40. This is effective also in enhancing the fixing strength of the wavelength conversion layer40.

FIGS. 10A to 10Care schematic sectional views showing alternative semiconductor light emitting devices according to the first embodiment.

As shown inFIG. 10A, in the semiconductor light emitting device112, the wavelength conversion layer40is spaced from the first semiconductor layer10. Thus, the wavelength conversion layer40does not necessarily need to be in contact with the first semiconductor layer10. In the case where the wavelength conversion layer40is spaced from the first semiconductor layer10, for instance, formation of the wavelength conversion layer40is easier than in the case where the wavelength conversion layer40is in contact with the first semiconductor layer10. In the semiconductor light emitting device112, transparent resin and the like may be embedded in the space between the first semiconductor layer10and the wavelength conversion layer40. Part of the transparent resin may extend out to e.g. the outside of the recess91. The transparent resin is preferably embedded so as not to form a gap between the transparent resin and the wavelength conversion layer40. This can enhance adhesiveness between the wavelength conversion layer40and the crystal layer. In this case, the transparent resin serves as an adhesive layer between the wavelength conversion layer40and the first semiconductor layer10, between the wavelength conversion layer40and the first insulating section61, and between the wavelength conversion layer40and the second insulating section62. This transparent resin is thinned by being sandwiched therebetween, and can be regarded substantially as a wavelength conversion layer40. A gap may occur between the transparent resin and the wavelength conversion layer40or between the transparent resin and the unevenness10v.

As shown inFIG. 10B, in the semiconductor light emitting device113, the height (position in the Z-axis direction) of the wavelength conversion layer40is higher than the height of the second insulating layer82. In other words, the thickness of the wavelength conversion layer40is thicker than the depth (length along the Z-axis direction) of the recess91. In the semiconductor light emitting device110, the height of the wavelength conversion layer40is substantially equal to the height of the second insulating layer82. However, as shown in the semiconductor light emitting device113, the height of the wavelength conversion layer40may be higher than that of the second insulating layer82. Thus, for instance, formation of the wavelength conversion layer40can be made easier than in the configuration of the semiconductor light emitting device110. Alternatively, the height of the wavelength conversion layer40may be lower than that of the second insulating layer82.

As shown inFIG. 10C, in the semiconductor light emitting device114, the wavelength conversion layer40is shaped like a plate. Furthermore, in the semiconductor light emitting device114, a transparent resin layer42is provided between the wavelength conversion layer40and the first semiconductor layer10. The transparent resin layer42has light transmissivity to the emission light of the light emitting layer30. For instance, the recess91is filled with the transparent resin layer42, and a plate-like wavelength conversion layer40is provided on the transparent resin layer42. Thus, the semiconductor light emitting device114is formed. In this configuration, for instance, formation of the wavelength conversion layer40is easier. The width (length along the X-axis direction) of the plate-like wavelength conversion layer40may be longer or shorter than the width of the recess91. In the case where the width of the wavelength conversion layer40is longer than the width of the recess91, for instance, alignment between the wavelength conversion layer40and the recess91is easier. On the other hand, in the case where the width of the wavelength conversion layer40is shorter than the width of the recess91, for instance, the wavelength conversion layer40can be fitted into the recess91.

Thus, the wavelength conversion layer40can be based on the configuration of being fitted into the recess91. The wavelength conversion layer40can be based on an arbitrary configuration in which the first semiconductor layer10can be placed between the light emitting layer30and the wavelength conversion layer40. A solid wavelength conversion layer40may be placed inside the recess91. Alternatively, a liquid material may be placed in the recess91and solidified to form a wavelength conversion layer40.

FIGS. 11A and 11Bare schematic views showing an alternative semiconductor light emitting device according to the first embodiment.

FIG. 11Ais a schematic plan view.FIG. 11Bis a schematic sectional view showing a cross section taken along line B1-B2ofFIG. 11A.

As shown inFIGS. 11A and 11B, in the semiconductor light emitting device115, the first electrode11is shaped like a frame. For instance, in this example, the first electrode11is shaped like a rectangle including a portion extending in the X-axis direction and a portion extending in the Y-axis direction.

FIG. 11Bshows a cross section of the portion of the first electrode11extending in the Y-axis direction. Furthermore, in the semiconductor light emitting device115, the third electrode13is placed around the center in the Y-axis direction.

In the semiconductor light emitting device115, the stacked body SB includes a first semiconductor layer10, a second semiconductor layer20, a third semiconductor layer23, a first light emitting layer31, and a second light emitting layer32.

The third semiconductor layer23is spaced from the first semiconductor layer10in the Z-axis direction, and spaced from the second semiconductor layer20in a third direction non-parallel to the Z-axis direction. The third semiconductor layer23is of the second conductivity type. The third direction may be an arbitrary direction non-parallel to the Z-axis direction.

The first light emitting layer31is provided between the first semiconductor layer10and the second semiconductor layer20. The second light emitting layer32is provided between the first semiconductor layer10and the third semiconductor layer23.

The first semiconductor layer10has a first portion10aopposed to the first light emitting layer31, a third portion10cjuxtaposed with the first portion10ain the third direction and opposed to the second light emitting layer32, and a fourth portion10dprovided between the first portion10aand the third portion10cin the third direction and not opposed to the first light emitting layer31and the second light emitting layer32. The third portion10chas a third side surface S3non-parallel to the X-Y plane.

The metal layer50(first metal layer) further includes a third side surface portion73s, a third bottom surface portion73b, and a fourth bottom surface portion74b. The third side surface portion73sis opposed to at least part of the wavelength conversion layer40, and the third side surface S3. The third bottom surface portion73bis opposed to the third portion10c. The fourth bottom surface portion74bis opposed to the fourth portion10d. The fourth bottom surface portion74bis continuous with the first bottom surface portion71band the third bottom surface portion73b. The first bottom surface portion71bis opposed to the first portion10a.

The distance D6between the third side surface S3and the third side surface portion73sand the distance D7between the wavelength conversion layer40and the third side surface portion73sare preferably less than or equal to e.g. the thickness t1in the Z-axis direction of the stacked body SB. This provides e.g. good heat dissipation. The distance D6and the distance D7are e.g. 10 μm or less. More preferably, the distance D6and the distance D7are e.g. 1 μm or less. This can provide e.g. good heat dissipation. Furthermore, the distance D6and the distance D7are e.g. 0.1 μm or more. This provides good insulation.

The semiconductor light emitting device115further includes a third insulating section63. The third insulating section63is provided between the third side surface S3and the third side surface portion73sand between the wavelength conversion layer40and the third side surface portion73s, and electrically insulates between the first semiconductor layer10and the metal layer50. The third insulating section63covers e.g. the third side surface S3. The third insulating section63covers e.g. the side surface of the wavelength conversion layer40. The third insulating section63includes e.g. a fifth insulating layer85provided between the metal layer50and the third side surface S3, and a sixth insulating layer86provided between the fifth insulating layer85and the third side surface S3. The first insulating layer81and the fifth insulating layer85may constitute one continuous layer. The second insulating layer82and the sixth insulating layer86may constitute one continuous layer. The third insulating section63is in contact with e.g. the metal layer50, the third side surface S3, and the wavelength conversion layer40. In this example, the third insulating section63extends also between the side surface23aof the third semiconductor layer23and the metal layer50and between the side surface32aof the second light emitting layer32and the metal layer50.

The first electrode11extends between the fourth portion10dand the fourth bottom surface portion74b. As described in the above embodiment, the first electrode11is electrically connected to the wiring layer80, and electrically connected to the third electrode13through the wiring layer80.

A seventh insulating layer87is provided between the fourth bottom surface portion74band the wiring layer80. The seventh insulating layer87electrically insulates between the metal layer50and the wiring layer80. An eighth insulating layer88is provided between the first electrode11and the second semiconductor layer20, between the first electrode11and the first light emitting layer31, and between the first electrode11and the second electrode12. The eighth insulating layer88electrically insulates between the first electrode11and the second semiconductor layer20, electrically insulates between the first electrode11and the first light emitting layer31, and electrically insulates between the first electrode11and the second electrode12. A ninth insulating layer89is provided between the first electrode11and the third semiconductor layer23, between the first electrode11and the second light emitting layer32, and between the first electrode11and the second electrode12. The ninth insulating layer89electrically insulates between the first electrode11and the third semiconductor layer23, electrically insulates between the first electrode11and the second light emitting layer32, and electrically insulates between the first electrode11and the second electrode12. The seventh insulating layer87may constitute one layer continuous with the first insulating layer81and the fifth insulating layer85. The eighth insulating layer88and the ninth insulating layer89may constitute one layer continuous with the second insulating layer82and the sixth insulating layer86.

Also in the semiconductor light emitting device115, as in the semiconductor light emitting device110, good heat dissipation can be obtained.

FIG. 12is a schematic sectional view showing a semiconductor light emitting device according to a second embodiment.

As shown inFIG. 12, the semiconductor light emitting device120of this example includes a first metal layer51and a second metal layer52. The first metal layer51and the second metal layer52enable energization from the rear surface side (opposite side from the light extraction surface).

The first semiconductor layer10has a first portion10aopposed to the light emitting layer30, and a second portion10bjuxtaposed with the first portion10ain a direction non-parallel to the Z-axis direction and not opposed to the light emitting layer30. The second portion10bhas a second side surface S2.

Like the metal layer50of the above first embodiment, the first metal layer51includes a first side surface portion71sand a first bottom surface portion71b. The first side surface portion71sis opposed to at least part of the wavelength conversion layer40, and the first side surface S1. Furthermore, like the metal layer50of the above first embodiment, the first metal layer51includes a first layer54and a second layer55.

In this example, the first insulating section61is formed from the first insulating layer81. The first insulating layer81is provided between the first side surface S1and the first side surface portion71sand between the wavelength conversion layer40and the first side surface portion71s. The first insulating layer81extends also between the side surface30aand the first metal layer51, between the side surface20aand the first metal layer51, between the side surface20band the first metal layer51, and between the side surface30band the first metal layer51. The first insulating layer81extends also between the second side surface S2and the second side surface portion72sand between the wavelength conversion layer40and the second side surface portion72s.

The second metal layer52includes a second side surface portion72sand a second bottom surface portion72b. The second side surface portion72sis opposed to at least part of the wavelength conversion layer40, and the second side surface S2. The second bottom surface portion72bis opposed to the second portion10b. The second metal layer52is electrically insulated from the first metal layer51. In this example, the second metal layer52is electrically insulated from the first metal layer51by separation between the first metal layer51and the second metal layer52. A dielectric, resin and the like having insulating property may be provided between the first metal layer51and the second metal layer52. The position of separation between the first metal layer51and the second metal layer52may be a position near the first electrode11as shown inFIG. 12, or may be a position near the second electrode12. Also in this example, the distance D8between the second side surface S2and the second side surface portion72sand the distance D9between the wavelength conversion layer40and the second side surface portion72sare preferably less than or equal to e.g. the thickness t1in the Z-axis direction of the stacked body SB. This provides e.g. good heat dissipation. The distance D8and the distance D9are e.g. 10 μm or less. More preferably, the distance D8and the distance D9are e.g. 1 μm or less. This can provide e.g. good heat dissipation. Furthermore, the distance D8and the distance D9are e.g. 0.1 μm or more. This provides good insulation.

In this example, the second metal layer52includes a third layer56and a fourth layer57. The third layer56is made of e.g. substantially the same material as the first layer54. The fourth layer57is made of e.g. substantially the same material as the second layer55.

The first electrode11is provided between the second portion10band the second bottom surface portion72b, and electrically connected to the first semiconductor layer10and the second metal layer52. The second electrode12is provided between the second semiconductor layer20and the first bottom surface portion71b, and electrically connected to the second semiconductor layer20and the first metal layer51. Thus, in the semiconductor light emitting device120, the light emitting layer30can be energized from the rear surface side by the first metal layer51and the second metal layer52.

Also in the semiconductor light emitting device120, as in the semiconductor light emitting device110, good heat dissipation can be obtained.

Next, a method for manufacturing the semiconductor light emitting device120is described.

FIGS. 13A to 13D,14A to14E, and15A to15D are schematic sectional views showing the method for manufacturing a semiconductor light emitting device according to the second embodiment.

As shown inFIG. 13A, a workpiece120wis prepared. The workpiece120wis substantially identical to the workpiece110w.

As shown inFIG. 13B, for instance, by photolithography processing and etching processing, part of the second semiconductor film20fand part of the light emitting film30fare removed.

As shown inFIG. 13C, for instance, by photolithography processing and etching processing, part of the first semiconductor film10fis removed to form a plurality of trenches90.

As shown inFIG. 13D, for instance, by film formation processing, a first insulating film81fis formed on each of the plurality of stacked bodies SB and on part of the substrate5exposed by the trench90.

As shown inFIG. 14A, for instance, by photolithography processing, etching processing, and evaporation technique or sputtering technique, a first electrode11is formed on each of the plurality of stacked bodies SB.

As shown inFIG. 14B, for instance, by photolithography processing, etching processing, and evaporation technique or sputtering technique, a second electrode12is formed on each of the plurality of stacked bodies SB.

As shown inFIG. 14C, for instance, by evaporation technique or sputtering technique, a conductive film55fconstituting a second layer55of a first metal layer51and a fourth layer57of a second metal layer52is formed on each of the plurality of stacked bodies SB. Here, a metal film (what is called the pad metal) for enhancing adhesiveness between the first electrode11and the conductive film55fmay be further provided between the first electrode11and the conductive film55f. Similarly, a metal film for enhancing adhesiveness between the second electrode12and the conductive film55fmay be further provided between the second electrode12and the conductive film55f. This metal film is made of e.g. a material including Ti, Pt, and Au.

As shown inFIG. 14D, for instance, by plating processing, a conductive film54fconstituting a first layer54of the first metal layer51and a third layer56of the second metal layer52is formed on each of the plurality of stacked bodies SB.

As shown inFIG. 14E, a plurality of trenches95for separation between the first metal layer51and the second metal layer52is formed in the conductive film54fand the conductive film55fby e.g. etching processing.

As shown inFIGS. 15A and 15B, for instance, by at least one of grinding processing and etching processing, the substrate5is removed.

As shown inFIG. 15C, for instance, by etching processing, part of the first semiconductor layer10is removed. Thus, the first semiconductor layer10is thinned, and a recess91and unevenness10vare formed.

As shown inFIG. 15D, by fitting a wavelength conversion material92into the recess91, a wavelength conversion layer40is formed. Subsequently, the plurality of stacked bodies SB are singulated. Thus, the semiconductor light emitting device120according to this embodiment is completed. Here, the wavelength conversion material92(wavelength conversion layer40) may be fitted after singulation. In this example, the semiconductor light emitting device120is formed by using the workpiece120win which the thickness of the first semiconductor film10fis thicker than the thickness of the first semiconductor layer10. The example is not limited thereto. For instance, like the example shown inFIGS. 6A to 6D,7A to7D,8A to8D, and9A to9C, the semiconductor light emitting device120may be formed by the method of forming a trench94removing part of the substrate5.

FIG. 16is a flow chart illustrating a method for manufacturing a semiconductor light emitting device according to a third embodiment.

As shown inFIG. 16, the method for manufacturing a semiconductor light emitting device according to the embodiment includes the step S110of preparing a workpiece110w, the step S120of forming a trench90, the step S130of forming a second insulating film82f, the step S140of forming a metal film50f, the step S150of removing the substrate5to expose the stacked body SB, and the step S160of forming a wavelength conversion layer40.

Thus, a semiconductor light emitting 110 having good heat dissipation is manufactured.

In the step S110, for instance, the processing described with reference toFIG. 2Ais performed. In the step S120, for instance, the processing described with reference toFIG. 2Cis performed. In the step S130, for instance, the processing described with reference toFIG. 2Dis performed. In the step S140, for instance, the processing described with reference toFIG. 4Bis performed. In the step S150, for instance, the processing described with reference toFIGS. 4C and 4Dis performed. In the step S160, for instance, the processing described with reference toFIG. 5Cis performed.

The embodiments provide a semiconductor light emitting having good heat dissipation and a method for manufacturing the same. The semiconductor light emitting according to the embodiments can be applied to wafer level packaging technique, and is effective for cost reduction.

In this specification, the “nitride semiconductor” includes semiconductors of the chemical formula BxInyAlzGa1-x-y-zN (0≦x≦1, 0≦y≦1, 0≦z≦1, x+y+z≦1) of any compositions with the composition ratios x, y, and z varied in the respective ranges. Furthermore, the “nitride semiconductor” also includes those of the above chemical formula further containing group V elements other than N (nitrogen), those further containing various elements added to control various material properties such as conductivity type, and those further containing various unintended elements.

In this specification, the state of being “provided on” includes not only the state of being provided in direct contact, but also the state of being provided with another element interposed in between. The state of being “stacked” includes not only the state of being stacked in contact with each other, but also the state of being stacked with another element interposed in between. The state of being “opposed” includes not only the state of directly facing, but also indirectly facing with another element interposed in between.

The embodiments of the invention have been described above with reference to examples. However, the embodiments of the invention are not limited to these examples. For instance, any specific configurations of various components such as the first semiconductor layer, second semiconductor layer, third semiconductor layer, first light emitting layer, second light emitting layer, stacked body, wavelength conversion layer, first metal layer, second metal layer, first electrode, second electrode, third electrode, first insulating section, wiring layer, insulating layer, unevenness, substrate, stacked film, first semiconductor film, second semiconductor film, light emitting film, workpiece, trench, insulating film, metal material, and metal film included in the semiconductor light emitting device and the method for manufacturing the same are encompassed within the scope of the invention as long as those skilled in the art can similarly practice the invention and achieve similar effects by suitably selecting such configurations from conventionally known ones.