JP6024432B2 - Semiconductor light emitting device - Google Patents

Description

  The present invention relates to a semiconductor light emitting device having inclined side surfaces.

Conventionally, in a semiconductor light emitting element such as an LED (light emitting diode), a structure in which a side surface of a semiconductor layer is inclined in consideration of light extraction efficiency has been proposed.
For example, in Patent Document 1 and Patent Document 2, the side surfaces are inclined so as to have a tapered frustum shape (hereinafter sometimes referred to as a forward taper shape as appropriate) in which the cross section of the semiconductor layer becomes narrower as it goes upward. The semiconductor light emitting device is sometimes described as being appropriately inclined. Further, for example, in Patent Document 3 to Patent Document 6, the side surfaces are arranged so as to have a tapered frustum shape (hereinafter sometimes referred to as a reverse taper shape as appropriate) in which the cross section of the semiconductor layer becomes wider toward the upper layer. A semiconductor light emitting element having an inclination (hereinafter sometimes referred to as a reverse inclination as appropriate) is described.
Patent Documents 7 and 8 describe semiconductor light-emitting elements whose side surfaces are reversely inclined so that the lower layer portion of the semiconductor layer has a reverse taper shape.

JP2011-228696A JP 2011-139038 A JP 2008-71910 A JP 2011-119383 A JP 2006-128659 A Japanese Patent Laid-Open No. 2006-191068 JP 2011-198997 A Japanese Patent Laid-Open No. 06-13654

  Here, with reference to FIG. 6, the light extraction optical path in the conventional semiconductor light emitting device will be described. 6A and 6B are schematic cross-sectional views for explaining an optical path from which light is extracted in a semiconductor light emitting device according to the prior art. FIG. 6A shows a forward tapered shape, and FIG. 6B shows a reverse tapered shape. Show. In any case, the upward direction is the light extraction direction.

First, as shown in FIG. 6A, the case where the semiconductor layer has a forward tapered shape will be described. The light beam L ₂₁ emitted from the active layer and propagating toward the upper part of the side surface is reflected by the side surface and extracted from the upper end surface like the light beam L ₂₂ . At this time, since the side surface is inclined inward (forward inclination), the light is reflected in a direction greatly inclined in the lateral direction with respect to the vertical direction. Further, when the reflective film is not provided on the side surface of the semiconductor layer, a part of the light beam L ₂₁ is extracted from the side surface to the outside like the light beam L ₂₃ . At this time, for example, when the refractive index of the semiconductor layer is relatively large like a nitride semiconductor, the light beam L ₂₃ is refracted to the semiconductor layer side with respect to the propagation direction of the light beam L ₂₁ .

Similarly, the light beam L ₂₄ emitted from the active layer and propagating toward the middle of the side surface is reflected by the side surface and is extracted from the upper end surface like the light beam L ₂₅ . Also in this case, since the light beam L ₂₅ is reflected by being tilted largely laterally with respect to the vertical direction on the side surface, the light path taken from the upper surface is long, and the amount of light absorbed by the semiconductor layer increases. Note that refracted light extracted from the side surface is omitted.

Further, in the region A under the side surface with the forward inclination, the light beam L ₂₆ emitted vertically upward from the active layer is reflected by the side surface and propagates obliquely upward like the light beam L ₂₇ .
The light beam L ₂₈ emitted downward from the active layer toward the side surface is reflected downward on the side surface like the light beam L ₂₉ , and propagates through a long optical path while repeatedly reflecting on the bottom surface and side surface. It is taken out from the upper surface.

When the side surface is forwardly inclined like the semiconductor light emitting devices described in Patent Document 1 and Patent Document 2, a long optical path is reflected from the side surface in the lateral direction or downward direction and taken out to the outside. Since the amount of light propagating in the semiconductor layer increases, the light absorption by the semiconductor layer is large, and the light extraction efficiency is reduced.
In addition, light rays that are extracted vertically upward from the vicinity of the forward inclined side surface are reduced, resulting in light intensity unevenness in which the amount of light at the end of the light emitting element is reduced.

Next, as shown in FIG. 6B, the case where the shape of the semiconductor layer is an inversely tapered shape will be described. When the side surface is inclined outward (reverse inclination), the light beam L ₃₁ emitted from the active layer toward the side surface is directed outward with respect to the vertical direction like the light beam L ₃₂ by the reverse inclined side surface. And is taken out from the upper surface. Further, in the case where no reflective film is provided on the side surface, a part of the light beam L ₃₁ is refracted from the side surface to the semiconductor layer side and extracted as the light beam L ₃₃ .

  As in the semiconductor light emitting devices described in Patent Document 3 to Patent Document 6, when the side surface is reversely inclined, the extracted light spreads outside in the region B under the reversely inclined side surface. Luminance unevenness in which the amount of light at the end portion is reduced occurs.

  Moreover, even when only the side surface of the lower layer portion is reversely inclined as in the light emitting elements described in Patent Document 7 and Patent Document 8, when the side surface of the upper layer portion is a vertical surface, the light beam tends to spread outward. Therefore, it has been desired to further reduce the brightness unevenness.

  This invention is made | formed in view of the said problem, and makes it a subject to provide a semiconductor light-emitting device with high light extraction efficiency.

In order to solve the above problems, a semiconductor light emitting device according to the present invention has a semiconductor stacked body including an active layer on a substrate, and the semiconductor stacked body has a lower layer portion including the active layer facing upward. And the upper layer part, which is a layer above the lower layer part, is connected to the upper end of the side surface of the lower layer part, and inwardly upward. possess inclined (forward inclination) side surfaces as narrower, the semiconductor laminate, in order from the substrate side, a first semiconductor layer, said active layer, a second semiconductor layer, are laminated, and the substrate A first electrode electrically connected to the first semiconductor layer and a second electrode electrically connected to the second semiconductor layer are disposed between the semiconductor stacked body and the first electrode. Covers substantially the entire area of the lower surface of the first semiconductor layer, and the second electrode A projecting portion disposed in a through-hole penetrating the first semiconductor layer and the active layer from the lower surface side of the body laminate, and a tip portion of the projecting portion is electrically connected to the second semiconductor layer. The protrusion has a shape that tapers upward, and the height of the upper surface of the protrusion from the lower surface of the first semiconductor layer is the first at the upper end of the side surface of the lower layer. It was configured to be higher than the height from the lower surface of the semiconductor layer .

  According to the semiconductor light emitting device according to the present invention, the light emitted from the active layer is reflected upward by the side surface of the upper layer portion inclined in the forward direction and the side surface of the lower layer portion inclined in the reverse direction, and propagated through the short optical path. Thus, the light extraction efficiency is improved because it can be efficiently extracted to the outside.

It is a schematic diagram which shows the structure of the semiconductor light-emitting device concerning embodiment of this invention, (a) is a top view, (b) is sectional drawing in the AA of (a). It is a schematic diagram which shows the structure of the semiconductor light-emitting device concerning embodiment of this invention, and is sectional drawing in the BB line of FIG. 1A (a). It is a typical top view showing composition of an electrode in a semiconductor light emitting element concerning an embodiment of the present invention, (a) is a wiring electrode of a p side electrode, (b) is a reflective electrode of a p side electrode, (c) is n A side electrode is shown. In the semiconductor light emitting element which concerns on embodiment of this invention, it is typical sectional drawing for demonstrating the optical path from which light is taken out. It is a flowchart which shows the flow of the manufacturing method of the light emitting conductor light emitting element which concerns on embodiment of this invention. (A)-(c) is typical sectional drawing which shows a part of manufacturing method of the semiconductor light-emitting device which concerns on embodiment of this invention. (A)-(c) is typical sectional drawing which shows a part of manufacturing method of the semiconductor light-emitting device which concerns on embodiment of this invention. (A)-(c) is typical sectional drawing which shows a part of manufacturing method of the semiconductor light-emitting device which concerns on embodiment of this invention. (A)-(c) is typical sectional drawing which shows a part of manufacturing method of the semiconductor light-emitting device which concerns on embodiment of this invention. (A), (b) is typical sectional drawing which shows a part of manufacturing method of the semiconductor light-emitting device based on embodiment of this invention. (A)-(c) is typical sectional drawing which shows a part of manufacturing method of the semiconductor light-emitting device which concerns on embodiment of this invention. (A)-(c) is typical sectional drawing which shows a part of manufacturing method of the semiconductor light-emitting device which concerns on embodiment of this invention. In the semiconductor light emitting element which concerns on a prior art, it is typical sectional drawing for demonstrating the optical path from which light is taken out, (a) In the case of forward taper shape, (b) shows the case of reverse taper shape.

  Hereinafter, semiconductor light emitting devices according to embodiments of the present invention will be described in detail with reference to the drawings. Note that the drawings referred to in the following description schematically show the present invention, and therefore the scale, spacing, positional relationship, etc. of each member are exaggerated, or some of the members are not shown. There is a case. Moreover, in the following description, the same name and code | symbol have shown the member same or the same quality in principle, and shall abbreviate | omit detailed description suitably.

<Embodiment>
[Configuration of Semiconductor Light Emitting Element]
The configuration of the semiconductor light emitting device 1 according to the embodiment of the present invention will be described with reference to FIGS. 1A, 1B, and 2. FIG.

  As shown in FIG. 1A (a), the semiconductor light emitting element 1 is formed in a substantially rectangular shape in plan view. In addition, as shown in FIGS. 1A (b) and 1B, the semiconductor light emitting device 1 includes a substrate-side bonding layer 13, an electrode-side bonding layer 14, and an n-side electrode on a support substrate 11 having a back surface adhesive layer 12 on the lower surface. 15 and the insulating film 16 are provided in this order, and a p-side electrode 17 is further provided on the insulating film 16, and a semiconductor laminate 19 is provided via the p-side electrode 17 or the protective film 18.

  The semiconductor multilayer body 19 has side surfaces inclined such that the lower layer portion 19L and the upper layer portion 19U have different inclination angles of the side surfaces, and the lower layer portion 19L including the active layer 192 spreads outwardly, and The upper layer portion 19U that is a layer above the lower layer portion 19L is connected to the upper end of the side surface of the lower layer portion 19L and has a side surface that is inclined so as to be narrowed inwardly upward. More specifically, the lower layer portion 19L is formed in a tapered frustum shape (inverted taper shape) that becomes wider as the cross section goes to the upper surface, and the upper layer portion 19U tapers that becomes narrower as the cross section goes to the upper surface. Further, the upper surface 191a of the upper layer portion 19U is roughened to have a fine uneven shape. In addition, the semiconductor stacked body 19 includes a p-type semiconductor layer 193 that is a first semiconductor layer, an active layer 192 and n, and an n-type semiconductor layer 191 that is a second semiconductor layer in order from the lower layer side (support substrate 11 side). , And the p-side electrode 17 as the first electrode electrically connected to the p-type semiconductor layer 193 and the n-type semiconductor layer 191 are electrically connected between the support substrate 11 and the semiconductor stacked body 19. An n-side electrode 15 that is a second electrode to be connected is disposed.

  The n-side electrode 15 has a plurality of protrusions 151, and is two-dimensionally arranged in a lattice form as shown in FIG. 1A (a). The protrusion 151 is provided in the through hole 20 that penetrates the p-type semiconductor layer 193 and the active layer 192 from the lower surface side of the semiconductor stacked body 19 via the insulating film 16 and the protective film 18, and the tip of the protrusion 151 is The insulating film 16 and the protective film 18 protrude from the opening of the opening protrusion 161 and are in contact with the n-type semiconductor layer 191.

  The p-side electrode 17 covers substantially the entire area of the lower surface of the p-type semiconductor layer 193, is provided on the wiring electrode 172 provided on the insulating film 16, and on the wiring electrode 172, and the p-type semiconductor layer 193 is provided. And a pad electrode 173 provided on the wiring electrode 172 and having an upper surface exposed from the protective film 18. As shown in FIG. 1A, the pad electrode 173 is arranged in a notch region provided on the lower side of the semiconductor laminate 19 that is substantially rectangular in plan view.

1A (b) corresponds to a cross section taken along line AA in FIG. 1A (a). Here, for convenience of illustration, six lines are provided on the line AA in FIG. 1A (a). Only one protrusion 151 of the n-side electrode 15 is illustrated, and similarly, only one opening protrusion 161 is illustrated.
1B corresponds to a cross section taken along line BB in FIG. 1A (a), but in the same manner as FIG. 1A (b), six lines are provided on line BB in FIG. 1A (a). Only one protrusion 151 of the n-side electrode 15 is shown on each side of the pad electrode 173, and similarly, only one opening protrusion 161 is shown.
Hereinafter, each component will be described in detail.

(Support substrate (substrate) 11)
The support substrate 11 is a substrate that is bonded to the semiconductor stacked body 19 via a member such as an electrode and supports the semiconductor stacked body 19. The support substrate 11 is formed in a substantially rectangular flat plate shape as shown in FIGS. 1A and 1B. Further, as shown in FIGS. 1A and 1B, the support substrate 11 has a back surface adhesive layer 12 formed on the bottom surface and a substrate side bonding layer 13 formed on the top surface. The area of the support substrate 11 is not particularly limited, and is appropriately selected according to the size of the member laminated on the support substrate 11. The thickness of the support substrate 11 is preferably 50 μm to 500 μm from the viewpoint of heat dissipation.

Specific examples of the support substrate 11 include a Si substrate, a semiconductor substrate made of GaAs, a conductive substrate made of a metal material such as Cu, Ge, Ni, or a composite material such as Cu-W. it can. Further, as the support substrate 11, a metal-ceramic composite such as Cu—Mo, AlSiC, AlSi, AlN, SiC, and Cu—diamond can be used in addition to the above. Such a composite has a general formula of Cu—W, Cu—Mo, for example, Cu _x W _100-x (0 ≦ x ≦ 30), Cu _x Mo _100-x (0 ≦ x ≦ 50). Respectively.

  Here, the Si substrate is cited as an example of the support substrate 11 because it has an advantage of being inexpensive and easy to chip. On the other hand, when a conductive substrate is used as the support substrate 11 as described above, there is an advantage that power can be supplied from the support substrate 11 side and an element having excellent heat dissipation can be obtained.

  The support substrate 11 is made of, for example, a material such as Si, Cu (Cu—W), and an electrode is provided between the support substrate 11 and the semiconductor stacked body 19, or between the semiconductor stacked body 19. It is preferable to provide a light reflecting structure on the surface. Thereby, the semiconductor light emitting element 1 can improve heat dissipation and light emission characteristics.

(Back side adhesive layer 12)
The back surface adhesive layer 12 is an adhesive member that is electrically connected to the support substrate 11 and that mounts the semiconductor light emitting element 1 on a mounting substrate (not shown) such as a light emitting device. The back surface adhesive layer 12 is formed in the whole area | region of the lower surface of the support substrate 11, as shown to FIG. 1A (b) and FIG. 1B. The thickness of the back surface adhesive layer 12 is not particularly limited, and can be appropriately adjusted according to desired bondability and conductivity. Specific examples of the back surface adhesive layer _12, TiSi 2, Ti, Pt, may be configured Ru, Au, Sn, a layer or the laminate structure including a metal such as Al. In addition, although the material similar to the board | substrate side joining layer 13 and the electrode side joining layer 14 which are mentioned later can be used for the back surface adhesive layer 12, you may use a conductive resin material, for example.

(Substrate side bonding layer 13)
The substrate-side bonding layer 13 is an adhesive member for bonding the support substrate 11 and the n-side electrode 15 together with the electrode-side bonding layer 14 and mechanically and electrically connecting them. The board | substrate side joining layer 13 is formed in the whole area | region of the upper surface of the support substrate 11, as shown to FIG. 1A (b) and FIG. 1B. The thickness of the board | substrate side joining layer 13 is not specifically limited, It can adjust suitably according to desired joining property and electroconductivity. Specific examples of the substrate-side bonding layer 13 include a layer containing a metal such as Al, Al alloy, Si, Ti, Pt, Au, Sn, Pd, Rh, Ru, In, Co, and Mo, or a laminated structure thereof. Can be configured.

Here, the substrate-side bonding layer 13 may have a stacked structure including an adhesion layer, a barrier layer, and a bonding layer. Accordingly, the support substrate 11 and the n-side electrode 15 can be bonded mechanically and electrically well, and the material can be prevented from migrating and bonded with high reliability. Further, when the substrate-side bonding layer 13 has the above-described metal laminated structure, it is preferable that the uppermost surface is made of Au in order to bond the electrode-side bonding layer 14 to the Au—Au, for example, in order from the support substrate 11 side. It can be laminated like TiSi ₂ / Pt / Au, Ti / Pt / Au, Ti / Ru / Au, Co / Mo / Au. Thus, since the tolerance to heat can be improved by bonding the bonding surface between the substrate-side bonding layer 13 and the electrode-side bonding layer 14 to heat, the reliability of the semiconductor light emitting element 1 can be improved. .

(Electrode side bonding layer 14)
The electrode-side bonding layer 14 is an adhesive member for mechanically and electrically bonding the support substrate 11 and the n-side electrode 15 together with the substrate-side bonding layer 13. The electrode side joining layer 14 is formed in the whole area | region of the lower surface of the n side electrode 15, as shown to FIG. 1A (b) and FIG. 1B. The thickness of the electrode side joining layer 14 is not specifically limited, It can adjust suitably according to desired joining property and electroconductivity. Specific examples of the electrode-side bonding layer 14 include Al, Al alloy, Si, Ni, Ti, Pt, Au, Sn, Pd, Rh, Ru, In, Co, as with the substrate-side bonding layer 13 described above. , Mo and other metal-containing layers and their laminated structures.

Here, the electrode-side bonding layer 14 may have a laminated structure including an adhesion layer, a barrier layer, and a bonding layer, similarly to the substrate-side bonding layer 13 described above. Accordingly, the support substrate 11 and the n-side electrode 15 can be bonded mechanically and electrically well, and the material can be prevented from migrating and bonded with high reliability. Further, when the electrode side bonding layer 14 has the above-described metal laminated structure, it is preferable that the lowermost surface is made of Au in order to bond the substrate side bonding layer 13 to the Au—Au, for example, from the n-side electrode 15 side. The layers can be sequentially laminated as TiSi ₂ / Pt / Au, Ti / Pt / Au, Ti / Ru / Au, Co / Mo / Au, and the like. Thus, since the resistance to heat can be improved by bonding the bonding surface between the electrode-side bonding layer 14 and the substrate-side bonding layer 13 with Au—Au, the reliability of the semiconductor light emitting element 1 can be improved. .

(N-side electrode (second electrode) 15)
The n-side electrode 15 is a negative electrode of the semiconductor light emitting device 1 for supplying current to the n-type semiconductor layer 191. The n-side electrode 15 is formed in the entire region of the upper surface of the support substrate 11 via the electrode-side bonding layer 14 and the substrate-side bonding portion 13 as shown in FIGS. 1A (b), 1B, and 2 (a). The insulating film 16 is disposed so as to face the p-side electrode 17. The n-side electrode 15 is formed in a wider range than the semiconductor stacked body 19. That is, the n-side electrode 15 is formed in an area larger than the area of the semiconductor stacked body 19 in plan view, and a step is formed in the outer edge portion 152 beyond the lower surface region of the semiconductor stacked body 19.

  The n-side electrode 15 includes a plurality of protrusions 151 that protrude toward the semiconductor multilayer body 19 (upward in FIGS. 1A (b) and 1B), and the tip of the protrusion 151 is an n-type semiconductor layer. 191 is electrically connected.

  As shown in FIG. 1A (b) and FIG. 1B, the protrusion 151 is provided in the through hole 20 that penetrates the p-type semiconductor layer 193 and the active layer 192 with an insulating film 16 and a protective film 18 interposed therebetween. The protruding portion 151 further protrudes from the opening portion of the opening protruding portion 161 of the insulating film 16 and the protective film 18, and the top surface and the side surface of the protruding portion are in contact with the n-type semiconductor layer 191. The semiconductor layer 191 is electrically connected.

In addition, although the protrusion 151 may be configured such that the top surface of the tip portion is in contact with the n-type semiconductor layer 191, it is preferable to further contact the side surface as in this example. As a result, the contact area between the projecting portion 151 and the n-type semiconductor layer 191 is increased, so that a current easily spreads in the n-type semiconductor layer 191 and the forward voltage Vf can be reduced.
The thickness of the n-side electrode 15 is not particularly limited, and can be adjusted as appropriate according to desired characteristics.

  The protrusion 151 has a shape that tapers upward, and has a tapered shape (frustum having a step between a lower portion whose side surface is covered with the insulating film 16 and the protective film 18 and the upper portion thereof. 1A (b) and FIG. 1B, it is formed in a substantially trapezoidal shape having a step in the sectional view. Moreover, the protrusion 151 is formed in an oval shape in a plan view as shown in FIG. Here, as shown in FIG. 2A, 48 protrusions 151 are formed in the lower portion of the semiconductor stacked body 19, and are connected to the semiconductor stacked body 19 at 48 locations.

Further, it is preferable that the height of the upper surface of the protrusion 151 from the lower surface of the p-type semiconductor layer 193 is higher than the height from the lower surface of the p-type semiconductor layer 193 at the upper end of the side surface of the lower layer portion 19L. That is, in the present embodiment, the height of the upper surface of the protruding portion 151 is higher than the upper end 19b of the lower layer portion 19L of the semiconductor stacked body 19 with respect to the lower end surface of the semiconductor stacked body 19, that is, the lower surface of the p-type semiconductor layer 193. Is provided at a high position. As a result, light propagating in the lateral direction or obliquely upward in the semiconductor stacked body 19 is reflected upward on the side surface of the tip portion of the protrusion 151, so that the light propagates outside without long propagation in the semiconductor stacked body 19. It can be taken out. As a result, the amount of light absorbed by the semiconductor stacked body 19 during propagation through the semiconductor stacked body 19 can be reduced, and the light extraction efficiency can be improved.
In addition, the inclination angle of the side surface of the tip portion of the protrusion 151 is preferably 30 degrees or more and 45 degrees or less, particularly preferably 35 degrees or more and 45 degrees or less with respect to the horizontal plane. As a result, light rays propagating at an angle close to the horizontal can be efficiently reflected upward.

In addition, although the protrusion part 151 has a level | step difference in this example, you may comprise so that it may not have a level | step difference. In this example, the shape of the protrusion 151 in plan view is an ellipse. However, the shape is not limited to this, and may be any shape such as a circle, an ellipse, a rectangle, or a polygon.
Moreover, it is good also as columnar shape which has not a taper shape but a perpendicular | vertical side surface.

As shown in FIGS. 1A (a) and 2 (a), the protrusions 151 are two-dimensionally arranged in a lattice pattern with equal intervals in the vertical and horizontal directions in plan view. Thus, the semiconductor light emitting element 1 can ensure a wide light emitting area because the plurality of protrusions 151 are dispersedly arranged in a small area. In addition, this makes it possible to make the current density uniform and reduce Vf (forward voltage), and uniform light emission is possible.
In addition, the number of the protrusions 151 and the arrangement method are not limited to this, and can be arbitrarily set.

As the n-side electrode 15, for example, an AlCu alloy can be used. In addition, for example, Ni, Pt, Pd, Rh, Ru, Os, Ir, Ti, Zr, Hf, V, Nb, Ta, Co, Fe, Mn, Mo, Cr, W, La, Cu, Ag , Y, Al, Si, Au, or an alloy containing these metals can be used. In addition, it can be formed of a single layer film or a laminated film including at least one selected from the group consisting of transparent conductive oxides such as ITO, ZnO, and In ₂ O ₃ . Further, as shown in FIGS. 1A (b) and 1B, the protrusion 151 is in contact with the n-type semiconductor layer 191 at the position of the tip, and the insulating film 16 and the protective film 18 at a position below the opening protrusion 161. Is insulated from the semiconductor stacked body 19. The tip portion of the projecting portion 151, particularly in contact with the n-type semiconductor layer 191, uses a light reflective material that reflects the light emitted from the active layer 192 while considering ohmic contact with the n-type semiconductor layer 191. Specifically, it is preferable to use Al and an Al alloy.

(Insulating film 16)
As shown in FIGS. 1A (b) and 1B, the insulating film 16 is formed so as to cover the entire region of the surface of the n-side electrode 15 except for the tip of the protruding portion 151 of the n-side electrode 15. The n-side electrode 15 and the p-side electrode 17 are insulated. Furthermore, the insulating film 16 insulates the protruding portion 151 of the n-side electrode, the p-type semiconductor layer 193 and the active layer 192 together with the protective film 18 in the through hole 20.

  More specifically, the insulating film 16 is formed between the n-side electrode 15 and the wiring electrode 172 that is a lower layer portion of the p-side electrode 17. In addition, the insulating film 16 covers the inner surface of the through hole 20 of the semiconductor stacked body 19 from the outside of the protective film 18, and the opening protrusion in which the tip of the protruding portion that covers the inner surface of the through hole 20 together with the protective film 18 opens. Part 161. The opening protrusions 161 are provided corresponding to the protrusions 151 of the n-side electrode 15, and in this example, 48 opening protrusions 161 are provided.

The thickness of the insulating film 16 is not particularly limited and can be appropriately adjusted according to desired characteristics. Specific examples of the insulating film 16 include, for example, a metal oxide film, a nitride film, an oxynitride film containing at least one element selected from the group consisting of Si, Ti, V, Zr, Nb, Hf, and Ta. In particular, it can be composed of SiO ₂ , ZrO ₂ , SiN, SiON, BN, SiC, SiOC, AlN, AlGaN, or the like. Further, the insulating film 16 may be composed of a single layer film or a laminated film of a single material, or may be composed of a laminated film of different materials. Further, the insulating film 16 is formed by laminating two or more kinds of light-transmitting insulating materials having different refractive indexes to form a DBR (Distributed Bragg Reflector) alone or together with the protective film 18. Also good.
Thereby, when the protective film 18 has translucency, the light transmitted from the semiconductor stacked body 19 through the protective film 18 can be reflected and returned to the semiconductor stacked body 19, and as a result, the light extraction efficiency can be improved. Can be improved.

(P-side electrode (first electrode) 17)
The p-side electrode 17 is a positive electrode in the semiconductor light emitting device 1 for supplying current to the p-type semiconductor layer 193. As shown in FIGS. 1A (b) and 1B, the p-side electrode 17 is formed in a film shape on the lower surface of the p-type semiconductor layer 193, and is disposed so as to face the n-side electrode 15 with the insulating film 16 interposed therebetween. ing. More specifically, the p-side electrode 17 includes a reflective electrode 171 connected to the p-type semiconductor layer 193, a wiring electrode 172 electrically connected to the p-type semiconductor layer 193 through the reflective electrode 171, and a wiring electrode 172 and a pad electrode (external connection portion) 173 for connecting to the outside.

As shown in FIGS. 1A (b), 1B, and 2 (b), the reflective electrode (light reflecting member) 171 is provided with a region where the protruding portion 151 of the n-side electrode 15 is provided and a protective film 18. In other words, it is formed on substantially the entire lower surface of the semiconductor stacked body 19, that is, the lower surface of the p-type semiconductor layer 193, excluding the region. The reflective electrode 171 is a full-surface electrode for uniformly diffusing current in the p-type semiconductor layer 193, and also functions as a reflective film for reflecting light emitted from the active layer 192 upward, which is the light extraction direction. Is.
For this reason, it is preferable that the reflective electrode 171 is excellent in ohmic contact with the p-type semiconductor layer 193 and efficiently reflects light from the active layer 192. A wiring electrode 172 is formed on the lower surface of the reflective electrode 171.

  The reflective electrode 171 is preferably configured with an area of 70% or more, more preferably 80% or more, still more preferably 90% or more, with respect to the area of the lower surface of the p-type semiconductor layer 193. It consists of the area. Thereby, contact resistance can be reduced and the drive voltage of the semiconductor light emitting element 1 can be reduced. In particular, by configuring the reflective electrode 171 to have an area of 70% or more with respect to the area of the p-type semiconductor layer 193, the light emitted from the active layer 192 is reflected in substantially the entire area of the lower surface of the p-type semiconductor layer 193. Therefore, the light extraction efficiency can be improved.

  Specifically, the reflective electrode 171 is composed of a plate-like member having substantially the same outer shape in plan view as the lower surface of the first semiconductor layer 193. As shown in FIG. A plurality of openings 171 a through which the opening protrusions 161 of the film 18 are inserted are formed concentrically with the opening protrusions 161.

  The reflective electrode 171 is preferably formed of a single layer film or a multilayer film of a metal or alloy containing at least one selected from Al, Rh, and Ag as a material that reflects light from the semiconductor multilayer body 19. More preferably, it is formed of a metal film containing Ag or an Ag alloy. Note that the reflective electrode 171 may have a configuration in which the side surface and the lower side (support substrate 11 side) are completely covered with another metal-containing layer serving as a cover electrode in order to prevent migration of a metal material such as Ag. Good. In the semiconductor light emitting device 1, the wiring electrode 172 is disposed below the reflective electrode 171 and the side surface of the reflective electrode 171 is covered with the protective film 18, as shown in FIGS. 1A (b) and 1B. These also play a role in preventing migration.

  The wiring electrode 172 is for supplying a current supplied via the pad electrode 173 to the p-type semiconductor layer 193 of the semiconductor stacked body 19 via the reflective electrode 171. As shown in FIGS. 1A, 1B, and 2C, the wiring electrode 172 faces the lower surface of the p-type semiconductor layer 193 except for the region where the opening protrusion 161 of the insulating film 16 is provided. It is formed in almost the entire area. A pad electrode 173 is provided on the upper surface of the wiring electrode 172 in the cutout region of the semiconductor stacked body 19.

  As shown in FIGS. 1A (b) and 1B, the wiring electrode 172 is specifically composed of a plate-like member whose outer shape in plan view is substantially the same as that of the support substrate 11, and is shown in FIG. 2 (c). As shown, a plurality of openings 172 a through which the opening protrusions 161 of the insulating film 16 are inserted are formed concentrically with the opening protrusions 161. In addition, like the reflective electrode 171, the wiring electrode 172 is preferably made of a material having a high reflectivity with respect to light from the active layer 192, and is preferably made of a highly conductive material. .

  The pad electrode (external connection portion) 173 is for connecting to an external power source in the p-side electrode 17. As shown in FIG. 1A (a), the pad electrode 173 is provided on the wiring electrode 172 in the cutout region of the semiconductor stacked body 19, and the upper surface is exposed from the protective film 18.

In this example, the pad electrode 173 is formed in a semicircular shape in plan view and is formed at a predetermined height. Further, a bump for connecting to an external wiring pattern (not shown) may be formed on the upper surface of the pad electrode 173.
The pad electrode 173 is preferably disposed in the peripheral region of the semiconductor light emitting element 1 as shown in FIG. 1A (a), considering that the conductive wire for external connection blocks light emission. For example, you may install in the center area | region of the semiconductor light-emitting device 1. FIG. The size, shape, number, and position of the pad electrode 173 are not particularly limited, and can be appropriately adjusted according to the size of the semiconductor light emitting element 1 and the size and shape of the semiconductor stacked body 19.

The thickness of each part of the p-side electrode 17 is not particularly limited, and can be appropriately adjusted according to desired characteristics. Specific examples of the wiring electrode 172 and the pad electrode 173 include, for example, Ni, Pt, Pd, Rh, Ru, Os, Ir, Ti, Zr, Hf, V, Nb, Ta, Co, Fe, Mn, Mo, It can be formed by a single layer film of a metal or alloy such as Cr, W, La, Cu, Ag, Y, Al, Si, Au, or a laminated film thereof.
In addition to this, it can also be formed by the above-described metal oxide or nitride, a single layer film made of a transparent conductive oxide such as ITO, ZnO, In ₂ O ₃ or a laminated film thereof.

(Protective film (light reflecting member) 18)
As shown in FIGS. 1A (b) and 1B, the protective film 18 is disposed in the same layer in a complementary manner to the reflective electrode 171, and the side surface of the lower layer portion 19L of the semiconductor laminate 19, the reflective electrode 171 and the protruding portion. The lower surface of the lower layer portion 19L excluding the region in contact with 151 is covered, and the surface of the semiconductor light emitting device 1 in the region excluding the pad electrode 173 outside the semiconductor stacked body 19 in a plan view is covered. It is an insulating film that protects from the atmosphere such as outside air.

  In the present embodiment, the protective film 18 covers the side surface of the lower layer portion 19L including the active layer 192 of the semiconductor stacked body 19 to prevent the active layer 192 from being deteriorated by outside air, but the upper layer portion 19U Do not cover. As a result, the side surface and the upper surface of the upper layer portion 19U are exposed from the protective film 18, and light is not absorbed by the protective film 18 when light is extracted from the upper layer portion 19U of the semiconductor stacked body 19. Will improve.

Further, the protective film 18 is preferably made of, for example, a light reflective resin in which a light diffusing material such as TiO ₂ is contained in a resin, or a light reflective member such as DBR. As a result, the light that has propagated through the semiconductor stacked body 19 and reached the surface covered with the protective film 18 can be efficiently reflected into the semiconductor stacked body 19. Further, by using a light-transmitting material having a lower refractive index than the semiconductor material constituting the semiconductor stacked body 19 as the protective film 18, at the interface between the protective film 18 that is a light-transmitting insulating film and the semiconductor stacked body 19. The light can be totally reflected. As such a material, for example, when the semiconductor material is a gallium nitride compound, a light-transmitting insulating material such as SiO ₂ can be used. Moreover, the thickness of the protective film 18 is not specifically limited, It can adjust suitably according to a desired characteristic.

(Semiconductor laminate 19)
In the semiconductor stacked body 19, a p-type semiconductor layer (first semiconductor layer) 193, an active layer 192, and an n-type semiconductor layer (second semiconductor layer) 191 are stacked in this order to constitute a light emitting unit in the semiconductor light emitting device 1. Is. The semiconductor laminate 19 is disposed on the support substrate 11 via a substrate side bonding layer 13, an electrode side bonding layer 14, an n side electrode 15, an insulating film 16, a p side electrode 17, and a protective film 18. . Further, in the semiconductor stacked body 19, the inclination of the side surface is different between the lower layer portion 19L including the active layer 192 and the upper layer portion 19U that is the upper portion thereof. With respect to the upward direction of FIG. 1A (b) and FIG. 1B, which is the light extraction direction, the lower layer portion 19L is formed in a truncated cone shape (reverse taper shape) that tapers upward and outwards upward. The upper layer portion 19U has a truncated cone shape (forward taper shape) that tapers upward and is connected to the upper end of the side surface of the lower layer portion 19L. It has an end portion side surface that is inclined (forward inclined) so as to be narrowed inwardly upward. Further, the upper surface 191a of the upper layer portion 19U, which is the upper surface of the semiconductor stacked body 19, is roughened, and a fine uneven shape is formed.
Note that the upper surface 191a may be configured not to be roughened, but is preferably roughened. Thereby, the light that has propagated through the semiconductor stacked body 19 and reached the upper surface 191a is diffused and emitted by the unevenness of the upper surface 191a, so that the light extraction efficiency is improved.

  The upper layer portion 19U has a forward tapered shape as shown in FIGS. 1A and 1B, and the outer edge end portion 19a on the upper surface of the semiconductor stacked body 19 is more than the perpendicular N1 of the outer edge end portion 19c of the active layer 192. A side surface with an inclination angle is formed so as to be on the outside. That is, the upper end of the side surface of the upper layer portion 19U is disposed outside the outer edge of the active layer 192 in plan view. The semiconductor stacked body 19 is formed in a rectangular shape that is substantially the same as or slightly smaller than the support substrate 11 in plan view, and a semispherical cutout region is provided in part in plan view. A pad electrode 173 is provided in the notch region.

  Although details will be described later, the end side surfaces of the upper layer portion 19U and the lower layer portion 19L have different inclination angles so that light emitted from the active layer 192 can be extracted efficiently and with little unevenness of light intensity. It is inclined at. For this reason, the end side surface of the upper layer portion 19U is preferably forwardly inclined with respect to a horizontal plane at an inclination angle of 75 degrees or more and less than 90 degrees, more preferably 75 degrees or more and 85 degrees or less, and the lower layer section 19L. It is preferable that the side surface of the end portion is reversely inclined with respect to a horizontal plane at an inclination angle of 30 degrees or more and 45 degrees or less, and more preferably 35 degrees or more and 45 degrees or less.

The semiconductor stacked body 19 has a plurality of through-holes 20 penetrating the p-type semiconductor layer 193 and the active layer 192 from the lower surface side, and a part of the n-type semiconductor layer 191 is removed. In this example, as shown in FIG. 1A (a), 48 through holes 20 are provided in a two-dimensional array in a lattice shape.
In each through hole 20, a protruding portion 151 of the n-side electrode 15 is provided via the insulating film 16 and the protective film 18, and protrudes from the opening of the opening protruding portion 161 of the insulating film 16 and the protective film 18. The tip of the protrusion 151 is in contact with and electrically connected to the n-type semiconductor layer 191. In addition, a reflection electrode 171 of the p-side electrode 17 is provided in substantially the entire area of the lower surface of the p-type semiconductor layer 193, and both are electrically connected. Further, the other surface of the lower layer portion 19 </ b> L is covered with the protective film 18. The upper layer portion 19U is not covered with the protective film 18 and is exposed.

Specific configurations of the n-type semiconductor layer 191, the active layer 192, and the p-type semiconductor layer 193 are not particularly limited, and may be any of InAlGaP-based, InP-based, AlGaAs-based, mixed crystals thereof, and nitride semiconductors such as GaN-based semiconductors. There may be. The nitride semiconductor includes GaN, AlN, InN, or a group III-V nitride semiconductor (In _X Al _Y Ga _1-XY N (0 ≦ X, 0 ≦ Y, X + Y), which is a mixed crystal thereof. ≦ 1)). Furthermore, the group III element may be partially or entirely used with B, and the group V element may be a mixed crystal in which a part of N is substituted with P, As, or Sb. These semiconductor layers are usually doped with either n-type or p-type impurities.

  In this embodiment, the p-type semiconductor layer 193 is used as the first semiconductor layer that is the lower semiconductor layer, and the n-type semiconductor layer 191 is used as the second semiconductor layer that is the upper semiconductor layer. However, the present invention is not limited to this, and the first semiconductor layer may be configured using an n-type semiconductor, and the second semiconductor layer may be configured using a p-type semiconductor.

  In the present embodiment, as a preferred form of the semiconductor light emitting device 1, the lower first semiconductor layer is composed of a p-type semiconductor layer 193, and the upper second semiconductor layer is composed of an n-type semiconductor layer 191. By making the resistance of the n-type semiconductor layer 191 on the upper layer side lower than that of the p-type semiconductor layer 193 on the lower layer side, current can be easily diffused in the n-type semiconductor layer 191 connected to the n-side electrode 15, thereby The concentration of current flowing through the body 19 can be further relaxed.

  Each of the n-type semiconductor layer 191 and the p-type semiconductor layer 193 constituting the semiconductor stacked body 19 may have a single layer structure, but a homostructure, a heterostructure, a double heterostructure, etc. having a MIS junction, a PIN junction, or a PN junction. The laminated structure may be used. Further, as shown in FIG. 1A (b) and FIG. 1B, the semiconductor light emitting element 1 is provided with an active layer 192 at a semiconductor junction which is a junction between the n-type semiconductor layer 191 and the p-type semiconductor layer 193, and the active An element in which the layer 192 serves as a light-emitting portion may be used, or an element in which the n-type semiconductor layer 191 and the p-type semiconductor layer 193 are in direct contact with each other to form a light-emitting portion. Note that the thicknesses of the n-type semiconductor layer 191, the active layer 192, and the p-type semiconductor layer 193 constituting the semiconductor stacked body 19 are not particularly limited, and can be appropriately adjusted according to desired characteristics.

[Operation of semiconductor light emitting device]
Next, the operation of the semiconductor light emitting element 1 will be described with reference to FIG. 3 (refer to FIGS. 1A and 1B as appropriate).
The semiconductor light emitting device 1 is bonded to a wiring pattern for a negative electrode of a mounting substrate (not shown) using a back surface adhesive layer 12 that is electrically connected to the n-side electrode 15, and is a pad electrode that is an external connection portion of the p-side electrode 17. 173 and the wiring pattern for the positive electrode of the mounting substrate are electrically connected by a bonding wire (not shown) or the like.

The semiconductor light emitting element 1 is supplied with electric power from an external power source via a wiring pattern (not shown) of the mounting substrate. The current supplied from the pad electrode 173 is supplied to the p-type semiconductor layer 193 through the wiring electrode 172 and the reflective electrode 171. This current further flows through the active layer 192 and the n-type semiconductor layer 191, and further, from the tip of the protruding portion 151 of the n-side electrode 15 to the flat portion on the lower side of the n-side electrode 15, the electrode-side bonding layer 14, and the substrate side The bonding layer 13, the conductive support substrate 11, and the back surface adhesive layer 12 flow in this order.
As the current flows in this manner, light is emitted from the active layer 192, and the emitted light propagates through the semiconductor stacked body 19 and is extracted from the upper layer portion 19U to the outside.

At this time, as shown in FIG. 3, the active layer 192, toward the side surface of the upper portion 19U formed in a forward tapered shape, light L ₁ propagating in the obliquely upward direction, the forward inclined side surfaces of the upper portion 19U in some is reflected on the upper surface 191a direction as beam L _2, it is taken out from the roughened top surface 191a. Another portion of the light beam L ₁ having reached the side surface of the upper portion 19U, as in the light L _3, is taken out to the outside is refracted upward from the side.
In the present embodiment, since the side surface and the upper surface of the upper layer portion 19U of the semiconductor stacked body 19 are exposed without being covered with the protective film 18, light is extracted without receiving extra light absorption by the protective film 18. Can do.

Here, the side surface of the semiconductor stacked body 19, at the same angle of inclination as the side surface of the lower portion 19L, when to have been formed as an extension N2 of the inclined surfaces, light L ₁ is straight as the ray L ₄ propagate, at the intersection of the extension line N2, as in the light L _5, is reflected upward slightly outwardly.
That is, as in the present embodiment, by spreading the side surface forward so that the upper layer portion 19U has a forward taper shape, the spread of light extracted from the vicinity of the outer edge end portion of the semiconductor stacked body 19 can be suppressed.

Further, the light beam L ₆ propagating obliquely upward at an angle close to the horizontal from the active layer 192 toward the side surface of the lower layer portion 19L formed in an inversely tapered shape is reflected on the side surface of the lower layer portion 19L inclined in the reverse direction. Like L ₇ , the light is reflected in the direction of the upper surface 191 a and taken out from the roughened upper surface 191 a.
Further, the light beam L ₈ propagating obliquely downward at an angle close to the horizontal direction from the active layer 192 toward the side surface of the lower layer portion 19L causes the upper surface 191a like the light beam L _{9 on} the reversely inclined side surface of the lower layer portion 19L. Reflected in the direction and taken out from the roughened upper surface 191a.

Here, as in the case of the light beam L ₆ and the light beam L ₈ , the light beam emitted from the active layer 192 at an angle close to the horizontal is formed when the side surface of the semiconductor stacked body 19 is formed forwardly or vertically to the lower end surface. The traveling direction does not turn upward in a single reflection, and reciprocates a number of times in the semiconductor laminate 19 before being taken out. For this reason, there is much light absorption by the semiconductor laminated body 19, and the light quantity taken out outside reduces. As in the present embodiment, the side surface of the lower layer portion 19L is reversely inclined so that the lower layer portion 19L has a reverse taper shape, thereby efficiently reflecting light rays propagating at an angle close to the horizontal upward and to the outside. It can be taken out.

In addition, the light beam L ₁₀ propagating in the lateral direction at an angle close to horizontal from the active layer 192 toward the side surface of the through hole 20 formed in the lower layer portion 19L is on the reversely inclined side surface on the through hole 20 side. Like the light beam L _11, the light is reflected in the direction of the upper surface 191 a and is extracted to the outside from the roughened upper surface 191 a. Similar to the light rays L ₆ and L ₈ propagating toward the outer edge side surface of the lower layer portion 19L, the side surface on the through hole 20 side is reversely inclined, so that the light can be efficiently reflected upward.

Further, the light beam L ₁₂ propagating upward from the active layer 192 approximately vertically reaches the roughened upper surface 191a as it is and is extracted outside without being reflected by the side surfaces.
As in the present embodiment, while the side surface of the upper layer portion 19U is inclined forwardly, the outer edge end portion 19a is inclined at an inclination angle so as to be outside the outer edge end portion 19c of the active layer 192. All the light rays emitted upward from the layer 192 substantially vertically are not reflected by the side surface of the upper layer portion 19U, but are directly taken out from the upper surface 191a through a short optical path, so that light absorption by the semiconductor stacked body 19 is prevented. It is suppressed.

The inverse from the active layer 192, toward the side surface of the upper portion 19U, light L ₁₃ which is a part of the light rays propagating in the obliquely upward direction, the boundary between the tip portion of the protruding portion 151 of the n-side electrode 15 in inclined inner surfaces, upwardly reflected as beam L _14, it is taken out from the upper surface 191a to the outside.
Here, when the upper surface of the protruding portion 151 is provided so as to be lower than the upper end 19b of the lower layer portion 19L, the light emitted from the active layer 192 is directly reflected by the tip portion of the protruding portion 151. There is no. Therefore, light rays L ₁₃ is straightly propagate in its extension direction as the ray L _15, reaches the outer edge side of the upper portion 19U, is reflected as beam L _16. That is, the light is absorbed by the semiconductor stacked body 19 while propagating through a long optical path in the semiconductor stacked body 19 and then extracted outside.
As in the present embodiment, the upper surface of the projecting portion 151 is provided so that higher than the upper end 19b of the lower portion 19L, light L ₁₃ having reached the front end portion of the projecting portion 151 efficiently be taken out Can do.

As described above, by configuring the semiconductor stacked body 19 as in the present embodiment, the amount of light extracted from the outer edge of the semiconductor stacked body 19 can be increased. Can be reduced.
In addition, by forming the semiconductor stacked body 19 as in the present embodiment, it is more preferable that the height of the upper surface of the projecting portion 151 be set higher than the height of the upper end 19b of the lower layer portion 19L to release from the active layer 192. The emitted light can be efficiently extracted outside.

[Method for Manufacturing Semiconductor Light-Emitting Element]
Hereinafter, a method of manufacturing the semiconductor light emitting device 1 according to the embodiment of the present invention will be described with reference to FIGS. 4 and 5A to 5G (refer to FIGS. 1A and 2 as appropriate).
5A to 5G referred to below are cross-sectional views corresponding to the cross section taken along the line AA of FIG. 1A (a), similar to the above-described FIG. 1A (b). Only one structure 20 and a related structure is shown, and the others are omitted.
Further, in this example, on the growth substrate Sb (for example, see FIG. 5A (a)), which will be described later, or on the support substrate 11 (hereinafter referred to as these substrates and semiconductor layers formed on the substrate, the wafers are collected. 1A), a plurality of semiconductor light emitting elements 1 having the structure shown in FIG. 1A are formed so as to be two-dimensionally arranged, and in the individualization step S27 (see FIG. 4) described later, individual semiconductors are formed. The light emitting element 1 is separated into individual pieces. 5A to 5G, only one of the semiconductor light emitting elements 1 is illustrated.

  As shown in FIG. 4, the method for manufacturing the semiconductor light emitting device 1 includes a semiconductor stacked body forming step S10, a first n-type semiconductor layer exposing step S11, a reflective electrode forming step S12, a protective film forming step S13, Wiring electrode forming step S14, insulating film forming step S15, second n-type semiconductor layer exposing step S16, n-side electrode layer forming step S17, n-side electrode layer flattening step S18, and bonding layer forming step S19 Support substrate bonding step S20, growth substrate peeling step S21, semiconductor layer polishing step S22, element isolation step S23, semiconductor layer roughening step S24, pad electrode forming step S25, and back surface adhesive layer forming step S26 and individualization process S27 are included.

In the method for manufacturing the semiconductor light emitting device 1, first, in the semiconductor stacked body forming step S10, as shown in FIG. 5A (a), the n-type semiconductor layer 191, the active layer 192, and the p-type semiconductor layer 193 are formed on the growth substrate Sb. Are sequentially laminated to form the semiconductor laminate 19.
The growth substrate Sb is a substrate for crystal growth of a semiconductor and is peeled off in a later process. The growth substrate Sb is made of, for example, sapphire whose main surface is any one of the C-plane, R-plane, and A-plane. A different substrate different from sapphire may be used as the growth substrate Sb. Examples of the heterogeneous substrate include an insulating substrate such as spinel (MgAl ₂ O ₄ ), an oxide substrate lattice-matched with SiC (including 6H, 4H, and 3C), ZnS, ZnO, GaAs, and a nitride semiconductor. A nitride semiconductor can be grown, and a conventionally known substrate material can be used.
Further, the semiconductor stacked body 19 can be formed by using, for example, MOCVD (metal organic chemical vapor deposition) method, MBE (molecular beam epitaxy) method, or the like.

Next, in the first n-type semiconductor layer exposing step S <b> 11, the notch region for forming the pad electrode 173, the outer edge portion, and the n-type semiconductor layer 191 in the region serving as the through hole 20 are exposed. The n-type semiconductor layer 191 can be exposed using a photolithography method.
Note that the through hole 20 is formed in two steps: a first n-type semiconductor layer exposure step S11 and a second n-type semiconductor layer exposure step S16 described later. In the first n-type semiconductor layer exposing step S11, the first stage of the through hole 20 is formed.

In this step, first, as shown in FIG. 5A (b), a mask M1 that covers a region other than the region where the n-type semiconductor layer 191 is exposed is provided using a photoresist.
Next, as shown in FIG. 5A (c), the semiconductor stacked body 19 in a region not covered with the mask M1 is removed by dry etching such as RIE (reactive ion etching) until the n-type semiconductor layer 191 is exposed from the upper surface. To do.

At this time, the three-dimensional shape of the mask M1 is transferred to the region of the semiconductor stacked body 19 that remains without being removed by etching. The region of the semiconductor stacked body 19 that has not been etched becomes the lower layer portion 19L of the semiconductor stacked body 19.
For this reason, the mask M1 extends in the semiconductor growth direction (upward in FIG. 5A (b)) so as to have substantially the same shape as that of the lower layer portion 19L of the semiconductor stacked body 19 shown in FIG. 1A (b). On the other hand, it is formed in a forward tapered shape. Then, by etching using the mask M1, as shown in FIG. 5A (c), the cutout region 19e, 1 stage 20 _first outer edge portion 19f and the through hole 20 is formed.

The inclination angle of the side surface of the mask M1 can be adjusted as follows. For example, by adjusting the viscosity of the photoresist, the side of the mask M1 is adjusted to a desired angle by controlling the amount of the end of the coating region that leaks when the photoresist is applied to the upper surface of the semiconductor stacked body 19. Can be tilted. In addition, the amount of the end portion, that is, the inclination angle can be adjusted by baking the photoresist.
Further, even if the side surface of the mask M1 is a vertical surface, the inclination angle of the side surface of the lower layer portion 19L can be adjusted by appropriately adjusting dry etching conditions such as atmospheric pressure.

Next, in the reflective electrode forming step S12, as shown in FIG. 3A in a plan view and as shown in FIG. 5B in a cross-sectional view, reflection is performed on substantially the entire region of the upper surface of the p-type semiconductor layer 193. An electrode 171 is formed.
At this time, the reflective electrode 171 can be formed by forming a film on the entire surface of the semiconductor stacked body 19 using an electrode material such as metal by sputtering or the like and patterning the film. Further, patterning of the formed metal layer or the like can be performed using a photolithography method, a lift-off method, or the like. Also in the subsequent steps, a film can be formed by an appropriate method according to the material to be used, and patterning can be performed by the same method as in this step. Therefore, description of the film formation and patterning is omitted as appropriate.

Next, in the protective film forming step S13, as shown in FIG. 5B (b), the protective film 18 is formed so as to cover the entire exposed surface of the semiconductor stacked body 19 except the region where the reflective electrode 171 is formed. . The protective film 18 can be formed, for example, by forming an insulating material such as SiO ₂ and patterning it by sputtering or the like. Further, when a resin containing a light reflecting member is used as the material of the protective film 18, the protective film 18 can be formed by a coating method. Depending on the material used, the protective film 18 can be formed by an appropriate method.

Next, in the wiring electrode formation step S14, as shown in FIG. 5B (c), the upper surface of the reflection electrode 171 and the cutout region 19e (see FIG. 5A (c)) are formed by the same method as in the reflection electrode formation step S12. A wiring electrode 172 is formed on the upper surface of the protective film 18 provided.
The wiring electrode 172 is formed as shown in FIG. 2C in plan view.

Next, in the insulating film forming step S15, as shown in FIG. 5C (a), an insulating material is used, for example, by sputtering so as to cover the wiring electrode 172 and the protective film 18, that is, the entire surface of the wafer. An insulating film 16 is formed.
The insulating film 16 can be formed by an appropriate method in accordance with the material to be used, similarly to the formation of the protective film 18 described above.

Then, in the second n-type semiconductor layer exposing step S16, as shown in FIG. 5C (b), the first stage 20 _first protective layer 18 and the through hole 20 covered with an insulating film 16, for example, dry etching Then, the n-type semiconductor layer 191 is exposed. As a result, the tips of the protruding portions of the insulating film 16 and the protective film 18 covering the inner surface of the through hole 20 are opened, and the opening protruding portion 161 is formed.

In this step, the n-type semiconductor layer 191 is also etched so as to be partially removed to a predetermined depth. The second stage 20 ₂ of the n-type semiconductor layer 191 etched by the through-hole 20 is formed.
In this step, a mask (not shown) is formed in a region other than the inside of the through hole 20 using, for example, a photoresist, and the inside of the through hole 20 is etched in the same manner as in the first n-type semiconductor layer exposing step S11. . Incidentally, the second stage 20 ₂ of the side surface of the through-hole 20 is to be inclined to the forward tapered shape to form the shape of the opening of the mask (not shown).

Next, in the n-side electrode layer forming step S17, as shown in FIG. 5C (c), the n-side electrode layer (metal) that becomes the n-side electrode 15 is formed on the entire wafer surface by using, for example, a metal material by sputtering. Layer). At this time, a metal material is embedded in the concave portion such as the through hole 20, and the thickness of the metal layer is set to a predetermined value in the concave portion, for example, with reference to the upper surface of the insulating film 16 provided on the p-type semiconductor layer 193. The film is formed so as to be equal to or greater than the thickness. Further, the metal material embedded in the through hole 20 becomes the protruding portion 151.
Note that the upper surface of the metal layer has irregularities corresponding to the surface shape of the wafer, but is flattened in the next step.

  Next, in the n-side electrode layer flattening step S18, as shown in FIG. 5D (a), the upper surface of the metal layer formed as the n-side electrode 15 is formed by, for example, CMP (Chemical Mechanical Polishing). Polish and flatten by the method. At this time, for example, the n-side electrode 15 is polished to have a predetermined thickness on the basis of the upper surface of the insulating film 16 provided on the p-type semiconductor layer 193.

  Next, in the bonding layer forming step S19, as shown in FIG. 5D (b), the electrode-side bonding layer 14 is formed on the flattened upper surface of the n-side electrode 15 by using, for example, a metal material by sputtering.

Next, in the support substrate bonding step S20, as shown in FIG. 5D (c), the wafer and the support substrate 11 provided with the substrate side bonding layer 13 on one side are bonded. At this time, the electrode-side bonding layer 14 and the substrate-side bonding layer 13 are bonded so as to face each other.
Note that the support substrate 11 provided with the substrate-side bonding layer 13 is prepared in advance by this step. For example, the substrate-side bonding layer 13 can be provided on one surface of the support substrate 11 by using a metal material by sputtering or the like.

Next, in the growth substrate peeling step S21, as shown in FIG. 5E (a), the growth substrate Sb and the semiconductor laminate 19 are irradiated with laser light from the growth substrate Sb side made of sapphire or the like, for example, by a laser lift-off method. The interface with (more specifically, the n-type semiconductor layer 191) is decomposed, and the growth substrate Sb is peeled off.
The growth substrate Sb may be peeled off by another method such as a chemical lift-off method.

Next, in the semiconductor layer polishing step S22, as shown in FIG. 5E (b), the surface of the n-type semiconductor layer 191 is polished and planarized by, for example, a CMP method. Further, after polishing by CMP, the surface may be removed by RIE.
In FIG. 5E (b) and subsequent figures, the upper and lower sides are inverted so that the support substrate 11 is on the lower side.

  Next, in the element separation step S23, the semiconductor stacked body 19 continuously formed on the wafer is separated for each light emitting element as a unit. More specifically, the semiconductor stacked body 19 is separated for each element by removing the n-type semiconductor layer 191 in the boundary region (street) of the light emitting element which becomes a cutting allowance in the individualization step S27 described later by etching. . At this time, in addition to the boundary region serving as a cutting allowance, the notch region of each light emitting element and the n-type semiconductor layer 191 at the outer edge portion are removed by etching, so that the outer edge end portion of the upper layer portion 19U of the semiconductor stacked body 19 is removed. Side surfaces inclined in a forward tapered shape are formed.

This step can be performed in the same procedure as the first n-type semiconductor layer exposure step S11 described above. First, as shown in FIG. 5F (a), a mask M2 is formed on the n-type semiconductor layer 191.
This mask M2 can be formed using a photoresist or the like. By etching the n-type semiconductor layer 191 using this mask M2, the shape is transferred to the lower n-type semiconductor layer 191 provided with the mask M2, as in the first n-type semiconductor layer exposing step S11. Is done. Accordingly, the mask M2 is formed to have a forward tapered side surface having substantially the same shape as the upper layer portion 19U of the semiconductor stacked body 19 of the completed semiconductor light emitting device 1 shown in FIG. 1A (b).

Further, the adjustment of the inclination angle of the side surface of the upper layer portion 19U of the semiconductor stacked body 19 can be performed in the same manner as the adjustment of the inclination angle of the side surface of the lower layer portion 19L.
If the inclination angle of the side surface of the upper layer portion 19U with respect to the vertical surface is slight, a mask M2 having a substantially vertical side surface is formed using a photoresist, and a baking process is performed so that the side surface of the mask M2 is bent. It is also possible to make an inclination angle.

  Then, using the mask M2, for example, dry etching is performed, and the n-type semiconductor layer 191 is removed until the protective film 18 is exposed. As shown in FIG. An upper layer portion 19U is formed.

Next, in the semiconductor layer roughening step S24, for example, by wet etching using TMAH (tetramethylammonium hydroxide), an aqueous KOH solution, ethylenediamine / pyrocatechol as an etching solution, as shown in FIG. 5F (c), The top surface 191a of the n-type semiconductor layer 191 is roughened to form a fine uneven shape.
Note that other regions which are not roughened during etching are masked by an appropriate method. The roughening can also be performed by dry etching.

Next, in the pad electrode formation step S25, as shown in FIG. 5G (a), a pad electrode 173 is formed in a predetermined region on the wiring electrode 172.
In this step, first, the protective film 18 covering the region where the pad electrode 173 is formed is removed by dry etching or the like, and the wiring electrode 172 is exposed.
Thereafter, a pad electrode is formed using a predetermined metal material by sputtering or the like.
The region where the pad electrode 173 is formed is a cutout region of the semiconductor stacked body 19 as shown in FIG. 1A (a).

  Next, in the back surface adhesive layer forming step S26, as shown in FIG. 5G (b), the back surface adhesive layer 12 as an ohmic electrode is formed on the back surface side of the support substrate 11 by using the above-described metal material by sputtering or the like. Form.

  Finally, in the singulation step S27, as shown in FIG. 5G (c), the semiconductor light emitting element 1 is singulated by cutting the wafer cutting margin by a dicing method, a scribe method, a laser scribe method, or the like. Thus, the semiconductor light emitting device 1 shown in FIG. 1A is completed.

  Although the semiconductor light emitting device and the manufacturing method thereof according to the present invention have been specifically described above by the embodiments for carrying out the invention, the gist of the present invention is not limited to these descriptions, and the scope of the claims Should be interpreted broadly based on the description. Needless to say, various changes and modifications based on these descriptions are also included in the spirit of the present invention.

  For example, in the embodiment, a nitride semiconductor is used as a semiconductor material, but the present invention is not limited to this, and other semiconductor materials may be used. Further, the semiconductor multilayer structure is not limited to the embodiment, and the semiconductor multilayer body is not transferred to the support substrate, and the n-type semiconductor layer and the p-type semiconductor layer are laminated in this order on the growth substrate. Also good. Furthermore, the electrode structure of the light-emitting element is not limited to the embodiment, and a pad electrode is provided as an external connection portion of the n-side electrode on the side where the semiconductor laminate is provided, so that the support substrate is electrically connected to the p-side electrode. The n-side pad electrode and the p-side pad electrode may be arranged on the same surface side of the substrate, or the protruding portion of the n-side electrode may not be provided.

1 Semiconductor Light Emitting Element 11 Support Substrate (Substrate)
12 backside adhesive layer 13 substrate-side bonding layer 14 electrode side junction layer 15 n-side electrode (second electrode)
151 projecting portion 152 outer edge portion 16 insulating film 161 opening projecting portion 17 p-side electrode (first electrode)
171 Reflective electrode (light reflecting member)
172 Wiring electrode 173 Pad electrode (external connection)
18 Protective film (light reflecting member)
19 Semiconductor Stack 191 N-type Semiconductor Layer (Second Semiconductor Layer)
192 Active layer 193 p-type semiconductor layer (first semiconductor layer)
20 Through-hole Sb Growth substrate

Claims (6)

On the substrate, has a semiconductor laminate including an active layer,
The semiconductor stacked body has a side surface that is inclined so that a lower layer portion including the active layer spreads outward and an upper layer portion that is a layer above the lower layer portion is the lower layer portion. the connected to the upper end of the side, it has a sloping sides so narrows inwardly upward,
In the semiconductor stacked body, a first semiconductor layer, the active layer, and a second semiconductor layer are stacked in order from the substrate side,
A first electrode electrically connected to the first semiconductor layer and a second electrode electrically connected to the second semiconductor layer are disposed between the substrate and the semiconductor stacked body,
The first electrode covers substantially the entire area of the lower surface of the first semiconductor layer,
The second electrode has a protruding portion disposed in a through-hole penetrating the first semiconductor layer and the active layer from a lower surface side of the semiconductor stacked body, and a tip portion of the protruding portion is the second semiconductor. Electrically connected to the layer,
The protruding portion has a shape that tapers upward, and the height of the upper surface of the protruding portion from the lower surface of the first semiconductor layer is such that the height of the first semiconductor layer at the upper end of the side surface of the lower layer portion A semiconductor light emitting element characterized by being higher than the height from the lower surface .   2. The semiconductor light emitting element according to claim 1, wherein, in a plan view, an upper end of a side surface of the upper layer portion is outside an outer edge of the active layer.   3. The semiconductor light emitting element according to claim 1, wherein a lower surface and a side surface of the lower layer portion are covered with a light reflecting member.   4. The semiconductor light emitting element according to claim 3, wherein a side surface and an upper surface of the upper layer part are exposed from the light reflecting member. The through hole is a semiconductor light emitting device according to any one of claims 1 to 4, characterized in that it has a shape that tapers upwardly. Upper surface of the upper portion, a semiconductor light emitting device according to any one of claims 1 to 5, characterized in that it has an uneven.

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