JP2014229626A - Semiconductor light emitting element array - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain luminance unevenness that might be formed on a semiconductor light emitting array including plural via-type semiconductor light emitting elements, and improve reliability of the semiconductor light emitting array.SOLUTION: The semiconductor light emitting array comprises: a supporting substrate; first to third light reflection conductive layers arranged on the supporting substrate, separated from each other, sequentially aligned in one direction, and having light reflectivity and electric conductivity; first semiconductor light emitting elements arranged on the first and second light reflection conductive layers; and second semiconductor light emitting elements spaced from the first semiconductor light emitting elements on the second and third light reflection conductive layers. A gap region defined in a gap between the first and second light reflection conductive layers and a gap between the second and third reflection conductive layers has at least one bending part in a plane view.

Description

  The present invention relates to a semiconductor light emitting element array including a semiconductor light emitting element having a via structure.

  A semiconductor light emitting device using a nitride semiconductor such as GaN can emit ultraviolet light or blue light, and can emit white light by using a phosphor. Such a semiconductor light emitting element is used for illumination, for example.

  The semiconductor light-emitting element includes, for example, an n-type GaN layer, a photo-semiconductor laminate in which a light-emitting GaN-based active layer and a p-type GaN layer are laminated, and a voltage applied to the photo-semiconductor laminate in contact with the n-type and p-type GaN layers. And an electrode to which can be applied. Semiconductor light emitting devices are classified into a counter electrode type, a flip chip type, a junction down type, a via type, and the like according to the structure and arrangement position of the electrodes.

  A sapphire substrate is generally used as a substrate for growing a GaN-based optical semiconductor stack. However, since the sapphire substrate has a relatively low thermal conductivity and poor heat dissipation, it is not suitable as a support substrate for a device to which a large current is input. Therefore, in recent years, after growing a GaN-based optical semiconductor stack on a sapphire substrate, the optical semiconductor stack is bonded to a silicon substrate that is advantageous for heat dissipation, and the sapphire substrate is removed by laser lift-off or polishing. It has been developed (for example, Patent Document 1).

  When a semiconductor light emitting element is used for illumination that requires high light output, for example, a vehicular lamp, a plurality of semiconductor light emitting elements are generally used connected in series or in parallel (semiconductor light emitting element array). In this case, a region where the semiconductor light emitting element is disposed is a light emitting region, and a region defined by a gap between the semiconductor light emitting elements is a non-light emitting region. There may be a significant light intensity distribution (brightness unevenness) between the light emitting region and the non-light emitting region.

JP 2010-056458 A

  An object of the present invention is to suppress luminance unevenness that may occur in a semiconductor light emitting element array including a plurality of via type semiconductor light emitting elements. Another object is to improve the reliability of the semiconductor light emitting element array.

  According to a main aspect of the present invention, a support substrate and first to third light reflections disposed on the support substrate and separated from each other and sequentially arranged in one direction and having light reflectivity and electrical conductivity. A first semiconductor light emitting element disposed on the conductive layer and the first and second light-reflective conductive layers, the first light-emitting conductive layer disposed above the first and second light-reflective conductive layers, and having a first conductivity type A lower semiconductor layer, a first active layer having a light emitting property, and a first upper semiconductor layer having a conductivity type different from the first conductivity type, and the first upper semiconductor layer is stacked on the first light; A first optical semiconductor stack electrically connected to the reflective conductive layer; and disposed between the second optical reflective conductive layer and the first optical semiconductor stack, the second light reflective conductive layer and the first lower side. A first conductive light-emitting element including a first conductive member that electrically connects the semiconductor layer; and the second and third optical reflectors. A second semiconductor light emitting element disposed on the conductive layer so as to expose the second light reflected light reflecting conductive layer with a gap from the first semiconductor light emitting element, wherein the second and third lights A second lower semiconductor layer disposed above the reflective conductive layer and having a second conductivity type; a second active layer having light emission properties; and a second upper semiconductor layer having a conductivity type different from the second conductivity type. A second optical semiconductor stack in which the second upper semiconductor layer is electrically connected to the second light-reflecting conductive layer, and disposed between the third light-reflecting conductive layer and the second photo-semiconductor stack. And a second semiconductor light emitting element including a second conductive member electrically connecting the third light reflective conductive layer and the second lower semiconductor layer, the first and second light reflective elements The gap between the conductive layers, and the gap region defined by the gap between the second and third light-reflecting conductive layers are planar. In the semiconductor light-emitting element array having at least one bend, it is provided.

  Luminance unevenness that can occur in a semiconductor light emitting element array including a plurality of via type semiconductor light emitting elements can be suppressed. In addition, the reliability of the semiconductor light emitting element array can be improved.

and, FIG. 1A is a plan view generally showing a semiconductor light emitting device array according to an embodiment, FIG. 1B is a cross-sectional view showing individual semiconductor light emitting devices constituting the semiconductor light emitting device array, and FIG. It is sectional drawing which shows the electrical connection structure in the adjacent semiconductor light-emitting device, and FIG. 1D-FIG. and, 2A to 2E are plan views showing the overall planar shape of the fusion layer, and FIG. 2F is a cross-sectional view showing another example of an electrical connection structure in semiconductor light emitting elements adjacent to each other. , and, 3A to 3L are cross-sectional views illustrating how the LED array according to the embodiment is manufactured.

  Hereinafter, a configuration of a semiconductor light emitting element array (LED array) according to an embodiment of the present invention will be described with reference to FIGS. 1A to 1F. The relative sizes of the components shown in the figure are different from the actual ones.

  FIG. 1A is a plan view generally showing an LED array 100 according to an embodiment. The LED array 100 includes, for example, a plurality of semiconductor light emitting elements (LED elements) 101 that are electrically connected in series, and a fluorescent layer 90 that covers the plurality of LED elements 101. Such an LED array 100 is used for, for example, a vehicular lamp.

  The plurality of LED elements 101 are supported on the support substrate 12 via a fusion layer (light reflective conductive layer) 70 having light reflectivity and electrical conductivity. On both ends of the support substrate 12, power supply pads 70p for supplying power to the plurality of LED elements 101 connected in series are placed.

In addition, the support substrate 12 is comprised from the member excellent in heat dissipation (high heat conductivity), for example, is comprised from Si. An insulating film 12 a containing SiO ₂ or the like is formed on the surface of the support substrate 12. The fluorescent layer 90 is made of a sealing resin containing phosphor fine particles, for example.

  FIG. 1B is a cross-sectional view showing any one LED element 101 constituting the LED array 100. FIG. 1B corresponds to, for example, the IB-IB cross section in FIG. 1A. Note that the plurality of LED elements 101 constituting the LED array 100 all have the same configuration. The LED element 101 has a configuration mainly including an optical semiconductor stack 20, a p-side electrode 30, an insulating layer 40, an n-side electrode 50, and a conductive layer 60.

  The optical semiconductor stack 20 has a multilayer structure in which at least a p-type semiconductor layer (lower semiconductor layer) 24, a light-emitting active layer (light-emitting layer) 23, and an n-type semiconductor layer (upper semiconductor layer) 22 are sequentially stacked. In the optical semiconductor stack 20, the surface on the p-type semiconductor layer 24 side is referred to as a first surface, and the surface on the n-type semiconductor layer 22 side is referred to as a second surface. At this time, the first surface of the optical semiconductor stack 20 has a concave region (via region) 20n where the n-type semiconductor layer 22 is exposed by removing (etching) the p-type semiconductor layer 24 and the active layer 23, and A convex region (flat region) 20p where the p-type semiconductor layer 24 is exposed is included. FIG. 1B shows a state in which one via region 20n is formed on the first surface of the optical semiconductor stack 20 for the sake of convenience. In practice, a plurality of via regions 20n are provided. (See FIG. 1D).

Each layer of the optical semiconductor stack 20 is composed of a GaN-based semiconductor represented by Al _x In _y Ga _z N (x + y + z = 1). The p-type semiconductor layer 24 and the n-type semiconductor layer 22 are made of, for example, p-type GaN and n-type GaN, respectively. The active layer 24 has a multiple quantum well structure including, for example, a barrier layer containing GaN and a well layer containing InGaN.

  The optical semiconductor stack 20 is not limited to such a configuration, and a so-called microcone structure layer (fine concavo-convex layer) 22 a may be formed on the upper surface of the n-type semiconductor layer 23. Also, for example, a clad layer (electron block layer) made of AlGaN may be included between the p-type semiconductor layer 24 and the active layer 23. Further, for example, a structure including a superlattice structure layer (strain relaxation layer) in which GaN and InGaN are stacked may be provided between the active layer 23 and the n-type semiconductor layer 22.

Further, on the second surface (the surface of the n-type semiconductor layer 22 and the surface of the microcone structure layer 22a) of the optical semiconductor laminate 20, a surface protective film 80 having an electrical insulating property made of SiO ₂ or the like is provided.

  The n-side electrode 50 is disposed on the first surface side of the optical semiconductor stack 20 in contact with the n-type semiconductor layer 22 in the via region 20n. For the n-side electrode 50, it is preferable to use a member having a high light reflectance such as Ag or Al.

  The p-side electrode 30 is disposed on the first surface side of the optical semiconductor stack 20 in contact with the p-type semiconductor layer 24 of the optical semiconductor stack 20 so as to avoid the n-side electrode 50 (or the via region 20n). The p-side electrode 30 is composed of a member including at least Ag having a high light reflectance.

The insulating layer 40 is disposed between the p-side electrode 30 and the n-side electrode 50 so as not to electrically connect the p-side electrode 30 and the n-side electrode 50 and covers the p-side electrode 30. Be placed. Further, the p-type semiconductor layer 24 and the active layer 23 and the n-side electrode 50 on the inner side surface of the via region 20n are arranged so as to cover the inner side surface of the via region 20n. The insulating layer 40 is made of, for example, SiO ₂ or SiN.

  The conductive layer 60 is disposed so as to cover the insulating layer 40, and the first conductive region 60 a that is electrically connected to the n-side electrode 50 and the first conductive region 60 a that is electrically connected to the p-side electrode 30 through the insulating layer 40. 2 conductive regions 60b. The first and second conductive regions 60a and 60b are arranged with a gap 60z therebetween and are electrically separated from each other. The conductive layer 60 is made of a member containing, for example, Ag having a high light reflectance.

  Power is supplied to the optical semiconductor stack 20 from the p-side electrode 30 and the n-side electrode 50 via the conductive layer 60 (first and second conductive regions 60a and 60b), that is, the p-type semiconductor of the optical semiconductor stack 20 Light is generated in the active layer 23 by injecting a current between the layer 24 and the n-type semiconductor layer 22. In the light emitted from the active layer 24, a part is directly emitted from the surface of the n-type semiconductor layer 22 (second surface of the optical semiconductor stack 20), and the other part is reflected by the p-side electrode 30. The light is emitted from the surface of the n-type semiconductor layer 22.

  FIG. 1C is a cross-sectional view showing an electrical connection structure of LED elements 101 adjacent to each other. Here, one of the plurality of LED elements 101 constituting the LED array 100 is referred to as a first LED element 101a, and the LED element 101 (adjacent to the first LED element 101a) ( The left LED element in the figure is referred to as a second LED element 101b.

  The first and second LED elements 101a and 101b are disposed above the support substrate 12 with a gap 101z therebetween, and are insulated on the surface via the fusion layer 70 including the first and second bonding layers 71 and 72. It physically bonds to the support substrate 12 on which the film 12a is formed. The fusion layer 70 includes a member having light reflectivity and conductivity, for example, Au, and has a plurality of fusion regions (physically and electrically separated from each other with a gap 70z therebetween). First to third fusion regions 70a to 70c) arranged toward the front.

  The first LED element 101a is disposed on the first and second fusion regions 70a and 70b of the fusion layer 70 so that the gap 60z (FIG. 1B) of the conductive layer 60 and the gap 70z of the fusion layer 70 overlap. The The via region 20 n of the optical semiconductor stack 20 is disposed above the first fusion region 70 a, and the first conductive region 60 a of the conductive layer 60 that is electrically connected to the n-side electrode 50 serves as the first fusion region 70. It is electrically connected to the landing area 70a. The second conductive region 60 b of the conductive layer 60 that is electrically connected to the p-side electrode 30 is electrically connected to the second fusion region 70 b of the fusion layer 70.

  Further, in the second LED element 101b, the gap 60z (FIG. 1B) of the conductive layer 60 and the gap 70z of the fusion layer 70 overlap the second and third fusion regions 70b and 70c of the fusion layer 70. Be placed. The via region 20 n of the optical semiconductor stack 20 is disposed above the second fusion region, and the first conductive region 60 a of the conductive layer 60 that is electrically connected to the n-side electrode 50 is the second fusion region of the fusion layer 70. It is electrically connected to the region 70b. Further, the second conductive region 60 b of the conductive layer 60 that is electrically connected to the p-side electrode 30 is electrically connected to the third fusion region 70 c of the fusion layer 70.

  The first fusion region 70a that conducts to the n-side electrode 50 of the first LED element 101a is a fusion region that conducts to the p-side electrode of the LED element disposed on the opposite side of the second LED element 101b, or a power supply pad 70p. (See FIG. 1A). In addition, the third fusion region 70c that conducts to the p-side electrode 30 of the second LED element 101b is a fusion region that conducts to the n-side electrode of the LED element disposed on the side opposite to the first LED element 101a, or power supply It is formed continuously with the pad 70p. Thereby, the several LED element 101 which comprises the LED array 100 is electrically connected in series.

  Note that the second fusion region 70b of the fusion layer 70 can be seen from the gap 101z between the first and second LED elements 101a and 101b.

  By supplying electric power from the power supply pad 70p (see FIG. 1A), current is injected into the optical semiconductor stack 20 (in particular, the active layer) of each of the plurality of LED elements 101 electrically connected in series, and the optical semiconductor stack Light is emitted from 20 (particularly the n-type semiconductor layer). In the case of the embodiment, since the optical semiconductor stack 20 is made of a GaN-based semiconductor, blue light or ultraviolet light is emitted. At this time, white light is emitted from the LED array 100 (see FIG. 1) by arranging the fluorescent layer 90 (see FIG. 1A) that emits yellow light on the plurality of LED elements 101 and in the gaps 101z thereof. Is done.

  1D to 1F are plan views showing LED elements 101 (first and second LED elements 101a and 101b) adjacent to each other. FIG. 1D mainly shows the overall planar shape of the optical semiconductor stack 20 in the first and second LED elements 101a and 101b. FIG. 1E mainly shows the overall planar shape of the p-side electrode 30 and the n-side electrode 50 in the first and second LED elements 101a and 101b. FIG. 1F shows the entire first and second conductive regions 60a and 60b of the conductive layer 60 and the first to third fusion regions 70a to 70c of the fusion layer 70 in the first and second LED elements 101a and 101b. The planar shape is mainly shown. In FIG. 1E and FIG. 1F, the optical semiconductor stack 20 is indicated by a broken line.

  As shown in FIG. 1D, the first and second LED elements 101a and 101b are arranged with a gap 101z therebetween. From the gap 101z between the first and second LED elements 101a and 101b, the second fusion region 70b of the fusion layer 70 can be seen.

  Here, the fusion layer 70 (second fusion region 70b) exposed from the gap 101z between the first and second LED elements 101a and 101b is a gap region 102 defined between the first and second LED elements 101a and 101b. Occupy most of the. For example, the area of the fusion layer 70 (second fusion region 70b) exposed from the gap 101z between the first and second LED elements 101a and 101b is 80% or more of the area of the gap region 102.

  By supplying power from the power supply pad 70p (see FIG. 1A), light is emitted from the optical semiconductor stack 20 of each of the plurality of LED elements 101 electrically connected in series. At this time, in the surface of the LED array 100 (see FIG. 1A), a region where the LED elements 101 are arranged is a light emitting region, and a region (gap region 102) defined by a gap between the LED elements 101 is a non-light emitting region. .

  When the fusion layer 70 does not occupy most of the gap region 102, most of the light emitted from the optical semiconductor stack 20 toward the support substrate 12 in the gap region 102 is a support substrate made of Si or the like. 12 and is not reflected on the light emitting surface side of the LED array 100. For this reason, significant luminance unevenness may occur between the light emitting region and the non-light emitting region. When the LED array 100 includes the light emitting layer 90 (see FIG. 1A), the balance between the light emission from the optical semiconductor stack 20 (for example, blue light) and the fluorescence by the fluorescent layer 90 (for example, yellow light) is light emission. This may be different between the region and the non-light emitting region, and may cause significant color unevenness.

  When the fusion layer 70 occupies most of the gap region 102, most of the light emitted from the optical semiconductor stack 20 toward the support substrate 12 in the gap region 102 has a light reflective property. 70 is reflected to the light emitting surface side of the LED array 100. For this reason, luminance unevenness that may occur between the light emitting region and the non-light emitting region is reduced. Further, when the LED array 100 includes the light emitting layer 90 (see FIG. 1A), color unevenness that may occur between the light emitting region and the non-light emitting region can be reduced.

  As described above, the light-reflecting fusion layer 70 exposed from the gap between the LED elements adjacent to each other occupies most of the gap region 102, so that the light emitting surface of the LED array is within the light emission surface. Brightness unevenness (or color unevenness) that can occur can be suppressed. However, even when the light-reflecting fusion layer 70 occupies most of the gap region 102, the light-emitting region and the non-light-emitting region are not used when the distance between the LED elements 101 adjacent to each other is extremely wide. Significant luminance unevenness may occur between the areas. Therefore, it is preferable that the interval between the LED elements 101 adjacent to each other is 80 μm or less.

  As shown in FIG. 1D, via regions 20n (regions surrounded by broken lines in the drawing) of the optical semiconductor stack 20 in each of the first and second LED elements 101a and 101b are, for example, circular, and each of the optical semiconductor stack 20 It is formed so as to be surrounded by the flat region 20p. Further, for example, five via regions 20n are provided so as to be uniformly distributed in the surface of the optical semiconductor laminate 20. The planar shape of the via region 20n is not limited to a circular shape, and may be an elliptical shape or a rectangular shape. Further, the number of via regions 20n is not limited to five and may be more.

  The size, shape, distribution density, and the like of the via region 20n (or flat region 20p) affect the light emission intensity, luminance unevenness, color unevenness, and the like of the LED array (or LED element). The size, shape, distribution density, and the like of the via region 20n (or flat region 20p) are desirably adjusted as appropriate according to the application of the LED array (or LED element).

  As shown in FIG. 1E, the n-side electrode 50 (the region indicated by the hatched pattern having a relatively narrow pitch in the drawing) is, for example, circular, and is formed in each via region 20n (see FIG. 1D) of the optical semiconductor stack 20. It is arranged at the corresponding position.

  A p-side electrode 30 (a region indicated by a hatched pattern with a relatively wide pitch in the drawing) is located at a position corresponding to the flat region 20p (see FIG. 1D) of the optical semiconductor stack 20, and the n-side electrode 50 (or via region 20n). ) And a circular opening 30h that can be seen through. The planar shape of the opening 30h is not limited to a circular shape, and may be an elliptical shape or a rectangular shape.

  As shown in FIG. 1F, the fusion layer 70 has a configuration in which first to third fusion regions 70a to 70c that are physically and electrically separated from each other with a gap 70z are arranged in one direction. On the first fusion region 70a of the fusion layer 70, the first conductive region 60a of the conductive layer 60 in the first LED element 101a (a region indicated by a diagonal pattern with a relatively small pitch in the drawing) is disposed. On the second fused region 70b of the fused layer 70, the second conductive region 60b of the conductive layer 60 in the first LED element 101a (a region indicated by a diagonal pattern with a relatively wide pitch in the figure), and the second LED A first conductive region 60a of the conductive layer 60 in the element 101b (a region indicated by an oblique line pattern having a relatively small pitch in the drawing) is disposed. On the third fused region 70c of the fused layer 70, a second conductive region 60b (a region indicated by a diagonal pattern having a relatively large pitch in the drawing) of the conductive layer 60 in the second LED element 101b is disposed.

  The first fusion region 70a that conducts to the n-side electrode 50 of the first LED element 101a is a fusion region (or power supply pad) that conducts to the p-side electrode of the LED element disposed on the side opposite to the second LED element 101b. 70p, see FIG. 1A). The third fusion region 70c that conducts to the p-side electrode 30 of the second LED element 101b is a fusion region (or power supply pad) that conducts to the n-side electrode of the LED element arranged on the opposite side of the first LED element 101a. 70p).

  According to further studies by the present inventors, as shown in FIG. 1F, when the planar shape of the gap 70z in the fusion layer 70 is a band shape extending in one direction as a whole, the gap 70z in the optical semiconductor stack 20 is obtained. It turned out that the part located above becomes easy to break. This is because the gap 70z is hollow (see FIG. 1C), and the portion located above the gap 70z of the optical semiconductor stack 20 is not supported, so that stress in a certain direction along the gap 70z is applied to the portion. It is thought that it is because it ends. The present inventors have examined the planar shape of the gap 70z that can suppress the cracking of the optical semiconductor stack 20.

  2A to 2D are plan views mainly showing an overall planar shape of the first to third fusion regions 70 a to 70 c in the fusion layer 70. 2A to 2D, the optical semiconductor stack 20 is indicated by a broken line. 2C and 2D indicate an a crystal plane (a plane) and an m crystal plane (m plane) of the optical semiconductor stack 20 composed of a GaN-based semiconductor having a hexagonal crystal structure. ) Along the direction.

  As shown in FIG. 2A and FIG. 2B, the planar shape of the gap 70z is not a belt-like shape extending in one direction, but a highly curved arch shape or a water surface wave shape having a plurality of curved portions. Cracks in the stack 20 can be suppressed. This is presumably because the stress applied to the optical semiconductor stack 20 is distributed in multiple directions.

  Further, as shown in FIG. 2C, even if the planar shape of the gap 70z is changed to a triangular wave shape or a saw shape having a plurality of refracted portions, the stress applied to the optical semiconductor stack 20 is alleviated and cracks in the optical semiconductor stack 20 are prevented. Can be suppressed. When the planar shape of the gap 70z in the fusion layer 70 includes portions extending in one direction (extension portions 70za and 70zb), the extension portions are along the a-plane and m-plane of the optical semiconductor stack 20. It is preferable that the direction is not parallel (intersects). This is because the optical semiconductor laminate is particularly easily broken (easy to cleave) in the direction along the a-plane and the m-plane.

  Furthermore, as shown in FIG. 2D, even when the planar shape of the gap 70z is changed to a rectangular wave shape or a trapezoidal wave shape having a plurality of refracted portions, the stress applied to the optical semiconductor stack 20 is alleviated and cracks in the optical semiconductor stack 20 are prevented. Can be suppressed. In addition, even when the planar shape of the gap 70z in the fusion layer 70 is a rectangular wave shape or a trapezoidal wave shape, portions that extend in one direction (elongation portions 70za and 70zb) are the same as in the case of a triangular wave shape or a sawtooth shape. Is preferably not parallel (intersects) with the direction along the a-plane and m-plane of the optical semiconductor stack 20. However, even if the extension portion is parallel to the direction along the a-plane and m-plane of the optical semiconductor stack, if the length D of the extension portion is about 50 μm or less, the cracking of the optical semiconductor stack can be suppressed. Is possible. The conditions concerning the length of the elongated portion are the same when the planar shape of the gap in the fusion layer is a triangular wave shape or a saw shape.

  As described above, the fusion layer 70 (first to third fusion regions 70a to 70c) is formed so that the gap 70z in the fusion layer 70 has at least one bent portion in plan view. Thereby, the crack of the optical semiconductor lamination | stacking 20 can be suppressed. Even when the gap 70z has a bent portion, the width W of the gap 70z, that is, the interval between the fusion regions separated from each other (the interval between the first and second fusion regions 70a and 70b, and When the distance between the second and second fusion regions 70b and 70c is wide, the effect of suppressing cracking of the optical semiconductor stack 20 is reduced. For this reason, the width W of the gap 70z is preferably 20 μm or less, and is preferably 5 μm or more in consideration of the manufacturing accuracy.

2E and 2F are a plan view and a cross-sectional view showing a configuration in which a support 73 for supporting the optical semiconductor laminate 20 is disposed in the gap 70z in the fusion layer 70. FIG. As described above, by disposing the support body 73 that supports the optical semiconductor stack 20 in the gap 70z having at least one bent portion, the stress applied to the optical semiconductor stack 20 is further reduced, and the optical semiconductor stack 20 is not cracked. Could be suppressed. The support 73 is made of an electrically insulating member such as silicon oxide or polyimide so that the fusion regions (first to third fusion regions 70a to 70c) separated from each other are not electrically connected. Hereinafter, with reference to FIGS. 3A to 3L, a method of manufacturing the LED array 100 according to the embodiment will be described. Specifically, two LED elements 101 adjacent to each other among the LED elements 101 constituting the LED array 100 will be described. Pay attention to the explanation. 3A to 3L are cross-sectional views showing a part of the LED array 100 for manufacturing.

  First, as shown in FIG. 3A, a growth substrate 11 made of a C-plane sapphire substrate is prepared, and an optical semiconductor stack 20 made of a GaN-based semiconductor is formed using a metal organic chemical vapor deposition (MOCVD) method. Specifically, first, the growth substrate 11 is thermally cleaned to grow the buffer layer 21 made of GaN. Subsequently, an n-type semiconductor layer 22 made of n-type GaN doped with Si or the like, an active layer (light emitting layer) 23 made of a multiple quantum well structure including a well layer (InGaN) and a barrier layer (GaN), Mg, etc. A p-type semiconductor layer 24 made of p-type GaN doped with is sequentially grown to form an optical semiconductor stack 20.

  The growth substrate 11 is a single crystal substrate having a lattice constant matching with the GaN crystal, and is 362 nm which is an absorption edge wavelength of the GaN crystal so that the growth substrate can be peeled off in a subsequent laser lift-off process (see FIG. 3J). Selected from those transparent to light. In addition to sapphire, spinel, ZnO, or the like can be used.

  In the optical semiconductor stacked layer 20, a strain relaxation layer having a superlattice structure including an InGaN layer and a GaN layer may be grown between the n-type semiconductor layer 22 and the active layer. Furthermore, a clad layer made of p-type AlGaN may be grown between the active layer 23 and the p-type semiconductor layer 24.

  Next, as shown in FIG. 3B, on the surface of the optical semiconductor stack 20 (the surface of the p-type semiconductor layer 24), for example, indium tin oxide (10 nm) / Ag (100 nm) / A multilayer film composed of TiW (250 nm) / Ti (50 nm) / Pt (100 nm) / Au (1000 nm) / Ti (30 nm) is formed and patterned by a photolithography method, a lift-off method, etc. The electrode 30 is formed. At this time, the p-side electrode 30 is patterned including an opening 30 h for forming the via 20 d in the optical semiconductor stack 20 in a subsequent step (FIG. 3C).

  Next, as shown in FIG. 3C, a region corresponding to the opening 30h of the p-side electrode 30 in the optical semiconductor stack 20 is etched by a dry etching method using a resist mask and chlorine gas, thereby forming a via 20d. . The via 20d is formed through the p-type semiconductor layer 24 and the active layer 23, and the n-type semiconductor layer 22 is exposed on the bottom surface of the via 20d. Thereby, a via region 20n corresponding to the via 20d and a flat region 20p other than the via region 20n are defined in the optical semiconductor stack 20 (see FIGS. 1B and 1D).

Next, as shown in FIG. 3D, an insulating layer 40 is formed to cover the inner surface of the p-side electrode 30 and the via 20d (via region 20n). First, a 300 nm-thickness SiO ₂ film is formed on the p-side electrode 30 and in the via 20d of the optical semiconductor stack 20 by sputtering or the like. Subsequently, the SiO ₂ film located on a part of the upper surface of the p-side electrode 30 and the bottom surface of the via 20 d is etched by a dry etching method using a resist mask and a CF 4 / Ar mixed gas, thereby forming the insulating layer 40. At this time, the n-type semiconductor layer 23 is exposed on the bottom surface of the via 20d. A part of the p-side electrode 30 is also exposed. As the insulating layer 40, in addition to SiO _2, it can be used SiN.

Next, as illustrated in FIG. 3E, an n-side electrode 50 that contacts the n-type semiconductor layer 22 is formed in the via 20 d of the optical semiconductor stack 20. First, Ti (1 nm) / Ag (200 nm) / Ti (100 nm) / Pt (200 nm) are formed on the insulating layer 40 and in the region where the n-type semiconductor layer 22 in the via 20d is exposed by electron beam evaporation or sputtering. ) / Au (200 nm). Subsequently, the metal multilayer film is patterned by a lift-off method or the like to form a columnar n-side electrode 50. The member used for the n-side electrode 50 preferably has a low contact resistance, for example, 1 × 10 ⁻⁴ Ωcm ² or less, and preferably has light reflectivity. Note that the n-side electrode 50 may be formed integrally with the conductive layer 60 in the step shown in FIG. 3F.

  Next, as illustrated in FIG. 3F, the conductive layer 60 and the first bonding layer 71 are formed on the insulating layer 40 and the n-side electrode 50.

  First, Ti (1 nm) / Ag (200 nm) / Ti (100 nm) / Pt (200 nm) / Au (200 nm) / Ti are formed on the insulating layer 40 and the n-side electrode 50 by electron beam evaporation or sputtering. A metal multilayer film (corresponding to a conductive layer) made of (50 nm) / Pt (100 nm) and a metal film (corresponding to the first bonding layer) made of Au (100 nm) are formed. Subsequently, the metal multilayer film and the metal film are patterned by a lift-off method or the like to form the conductive layer 60 and the first bonding layer 71 including the gap 60z. The conductive layer 60 is divided into first and second conductive regions 60a and 60b by a gap 60z. The first bonding layer 71 is divided into regions corresponding to the first and second conductive regions 60 a and 60 b of the conductive layer 60.

  Next, as shown in FIG. 3G, a part of the optical semiconductor stack 20 is etched by a dry etching method using a resist mask and chlorine gas to divide the optical semiconductor stack 20 into a desired size. Each of the divided optical semiconductor stacks 20 corresponds to the optical semiconductor stack of the individual LED elements 101 constituting the LED array 100 (see FIG. 1A). Further, the removed region of the optical semiconductor stack 20 corresponds to the gap 101z between the LED elements 101 adjacent to each other (see FIG. 1D). Hereinafter, for convenience, a structure in which the layers from the optical semiconductor stack 20 to the first bonding layer 71 are formed on the growth substrate 11 is referred to as a device structure 103.

Next, as shown in FIG. 3H, a support substrate 12 having a second bonding layer 72 formed on the surface is prepared. For the support substrate 12, a member having a thermal expansion coefficient close to that of sapphire (7.5 × 10 ⁻⁶ / K) or GaN (5.6 × 10 ⁻⁶ / K) is preferably used. For example, Si, Ge, Mo, CuW, AlN, etc. can be used. When a Si substrate is used as the support substrate 12, for example, the insulating film 12a made of SiO ₂ is formed by thermally oxidizing the surface of the Si substrate.

  After that, a metal multilayer film made of Ti / Ni / Au / Pt / AuSn (Sn: 20 wt%) is formed on the support substrate 12 (insulating film 12a) by sputtering or the like, and by photolithography or lift-off or the like. Patterning is performed to form a second bonding layer 72 including a plurality of fusion regions (here, first to third fusion regions 70a to 70c) divided by the gap 70z. The member used for the second bonding layer 72 (the uppermost film of the metal multilayer film) and the first bonding layer 71 bonded to the second bonding layer 72 is Au-Sn, Au-In, Pd-In, which can be fusion bonded. A metal containing Cu—In, Cu—Sn, Ag—Sn, Ag—In, Ni—Sn, or the like, or a metal containing Au capable of diffusion bonding can be used.

  Next, as shown in FIG. 3I, the device structure 103 already prepared and the prepared support substrate 12 are arranged so that the first and second bonding layers 71 and 72 are opposed to each other, and the pressure is 300 MPa while pressing at 3 MPa. Hold for 10 minutes while heated to ° C. Note that the device structure 103 and the support substrate 12 are arranged so that the gap 60z of the conductive layer 60 and the gap 70z of the second bonding layer 72 overlap each other. Then, it cools to room temperature and the 1st, 2nd contact bonding layers 71 and 72 are fusion-bonded (fusion layer 70). Note that the planar shape of the gap 70z in the fusion layer 70 (and the gap 60z in the conductive layer 60) is, for example, the shape shown in FIGS. 2A to 2D.

Next, as shown in FIG. 3J, the optical semiconductor stack 20 and the growth substrate 11 are separated by a laser lift-off method. Specifically, the optical semiconductor stack 20 is irradiated with KrF excimer laser light (wavelength: 248 nm, irradiation energy density: 800 to 900 mJ / cm ² ) from the growth substrate 11 side, and a part of the buffer layer 21 is thermally decomposed. As a result, the growth substrate 11 and the optical semiconductor stack 20 are separated.

  Thereafter, Ga generated by thermal decomposition of the buffer layer 21 (GaN crystal) is removed with hot water or the like, and the surface of the optical semiconductor stack 20 with hydrochloric acid, sodium hydroxide, or the like (a part of the buffer layer 21 and the n-type semiconductor layer 22). Etch. As a result, the n-type semiconductor layer 22 of the optical semiconductor stack 20 is exposed.

Next, as shown in FIG. 3K, a so-called microcone structure layer 22 a is formed on the surface of the n-type semiconductor layer 23 of the optical semiconductor stack 20. Specifically, the surface of the n-type semiconductor layer 22 is wet-etched with a TMAH (phenyltrimethylammonium hydroxide) aqueous solution (temperature about 70 ° C., concentration about 25%) or the like. Subsequently, a surface protective film 80 made of SiO ₂ or the like is formed on the n-type semiconductor layer 22 (microcone structure layer 22a) by a chemical vapor deposition (CVD) method or the like. Thus, the individual LED elements 101 constituting the LED array 100 are completed.

  Thereafter, for example, the support substrate 12 is divided by laser scribing or dicing so that four LED elements 101 are arranged in one direction (see FIG. 1A).

  Subsequently, as shown in FIG. 3L, for example, a resin containing phosphor fine particles 91 that emits yellow light is dropped on the entire surface of the support substrate 12 so as to cover the plurality of LED elements 101, and is cured. 90 is formed. Thus, the LED array 100 is completed.

When a support (see FIG. 2F) that supports the optical semiconductor stack is formed in the gap in the fusion layer, sputtering and lift-off are applied to the gap 60z and the gap 70z in the steps shown in FIGS. 3F and 3H. An insulating member such as SiO ₂ may be formed using a method or the like.

  As mentioned above, although this invention was demonstrated along the Example and the modification, this invention is not limited to these. For example, the LED elements constituting the LED array may not have a via structure. That is, it is not a structure in which a via is formed in the optical semiconductor stack and the n-type semiconductor layer and the fusion layer exposed in the via are electrically connected, but the n-side electrode is formed on the surface (upper surface) of the n-type semiconductor layer. It may be a structure (counter electrode structure) formed and provided with a member that electrically connects the n-side electrode and the fusion layer through the side surface of the optical semiconductor stack. It will be apparent to those skilled in the art that other various modifications, improvements, combinations, and the like are possible.

DESCRIPTION OF SYMBOLS 11 ... Growth substrate, 12 ... Support substrate, 12a ... Insulating film, 20 ... Optical semiconductor lamination, 20p ... Flat region (convex region, p-type semiconductor layer exposed region), 20n ... Via region (concave region, n-type semiconductor layer) Exposed region), 21 ... buffer layer, 22 ... n-type semiconductor layer, 22a ... microcone structure layer, 23 ... active layer (light emitting layer), 24 ... p-type semiconductor layer, 30 ... p-side electrode, 40 ... insulating layer 50 ... n-side electrode, 60 ... conductive layer, 60a ... first conductive region, 60b ... second conductive region, 60z ... gap, 70 ... fusion layer, 70a ... first fusion region, 70b ... second fusion Region 70c ... third fusion region 70z ... gap 71 ... first bonding layer 72 ... second bonding layer 73 ... support body 80 ... surface protective film 90 ... phosphor layer 91 ... phosphor fine particles, DESCRIPTION OF SYMBOLS 100 ... LED array, 101 ... LED element, 102 ... Gap area | region, 103 ... Deva Scan structure.

Claims (5)

A support substrate;
First to third light-reflective conductive layers having light reflectivity and electrical conductivity, disposed on the support substrate and arranged in order in one direction separated from each other;
A first semiconductor light emitting device disposed on the first and second light-reflecting conductive layers,
A first lower semiconductor layer having a first conductivity type, a first active layer having light emission properties, and a conductivity type different from the first conductivity type are disposed above the first and second light reflecting conductive layers. A first optical semiconductor stack having a first upper semiconductor layer sequentially stacked, and the first upper semiconductor layer electrically connected to the first light-reflecting conductive layer;
A first conductive member disposed between the second light-reflective conductive layer and the first photo-semiconductor stack and electrically connecting the second light-reflective conductive layer and the first lower semiconductor layer;
A first semiconductor light emitting device comprising:
A second semiconductor light-emitting element disposed on the second and third light-reflecting conductive layers with a gap from the first semiconductor light-emitting element so that the second light-reflected light reflecting conductive layer is exposed; ,
A second lower semiconductor layer having a second conductivity type, a second active layer having a light emitting property, and a conductivity type different from the second conductivity type, disposed above the second and third light-reflecting conductive layers; A second optical semiconductor stack having a second upper semiconductor layer sequentially stacked, and the second upper semiconductor layer electrically connected to the second light-reflecting conductive layer;
A second conductive member disposed between the third light-reflecting conductive layer and the second photo-semiconductor stack and electrically connecting the third light-reflecting conductive layer and the second lower semiconductor layer;
A second semiconductor light emitting device comprising:
With
The gap between the first and second light-reflecting conductive layers and the gap region defined by the gap between the second and third light-reflecting conductive layers have at least one bent portion in plan view. .   The semiconductor light emitting element array according to claim 1, wherein the gap region has a water surface wave shape in plan view.   The gap region has at least a first extension portion extending in a first direction and a second extension portion extending in a second direction different from the first direction in plan view. The semiconductor light-emitting element array according to claim 1. The first and second optical semiconductor stacks have a hexagonal crystal structure including an a-plane and an m-plane,
4. The semiconductor light emitting element array according to claim 3, wherein the first and second extending portions extend in a direction intersecting with a-plane and m-plane of the first and second optical semiconductor stacks. The first and second optical semiconductor stacks have a hexagonal crystal structure including an a-plane and an m-plane,
4. The semiconductor according to claim 3, wherein the first and second elongated portions extend in directions parallel to the a-plane and the m-plane of the first and second optical semiconductor stacks, and each length is 50 μm or less. Light emitting element array.

Images