Light-emitting element, driving element, light-emitting device, distance measuring device, and electronic apparatus

Abstract

The principal purpose of the present technology is to provide a technique for suppressing warpage of a wafer.　The present technology provides a light-emitting element (1) having: a plurality of mesa portions (41) that emit light; an insulating layer (18) disposed between the adjacent mesa portions (41); and an internal space (4) formed in a part of each insulating layer (18). The present technology also provides a driving element (2) having: a plurality of electrodes (22) electrically connected to respective ones of the plurality of mesa portions (41) of the light-emitting element (1), and for driving the light-emitting element (1); an insulating layer (21) disposed between the adjacent electrodes (22); and an internal space (4) formed in a part of each insulating layer (21).

Description

Light-emitting element, driving element, light-emitting device, distance measuring device, and electronic equipment

[0001] The technology disclosed herein (hereinafter also referred to as "this technology") relates to light-emitting elements, driving elements, light-emitting devices, distance measuring devices, and electronic equipment.

[0002] Conventionally, in the manufacturing of light-emitting devices, a light-emitting element and a drive element for driving the light-emitting element are joined together.

[0003] For example, Patent Document 1 discloses a technology relating to a "micro-light-emitting element characterized in that the surface of the other side of the first electrode and the surface of the other side of the second electrode lie on the same plane, and both the first electrode and the second electrode consist of a single wiring layer."

[0004] Japanese Patent Publication No. 2019-204823

[0005] During the bonding of the light-emitting element and the driving element, wafer warping may occur due to film stress in the insulating layer. This wafer warping may lead to a decrease in bonding strength or connection failure.

[0006] Therefore, the primary objective of this technology is to provide a technique for suppressing wafer warping.

[0007] This technology provides a light-emitting element having a plurality of light-emitting mesa portions, with insulating layers disposed between each of the mesa portions, and an internal space formed in a part of each of the insulating layers. An internal space may be formed in all of the insulating layers. The thickness of the insulating layer located on the outer periphery of the light-emitting element may be greater than the thickness of the insulating layer located on the inner periphery. The thickness of the insulating layer covering the mesa portions may be 1 μm or more. The thickness of the insulating layer covering the region opposite to the end of the mesa portion may be greater than the thickness of the insulating layer covering the end. The height of the mesa portions may be 2 μm or more. The internal space may be filled with an insulating material different from the material of the insulating layer. A polymer material may be used as the material of the insulating layer. Furthermore, this technology provides a driving element having a plurality of electrodes electrically connected to each of the plurality of mesa portions of the light-emitting element for driving the light-emitting element, with insulating layers disposed between each of the electrodes, and an internal space formed in a part of each of the insulating layers. An internal space may be formed in all of the insulating layers. Furthermore, this technology provides a light-emitting device comprising: a light-emitting element having a plurality of mesa portions; and a driving element electrically connected to each of the plurality of mesa portions and having a plurality of electrodes for driving the light-emitting element, wherein an insulating layer is disposed between each of the mesa portions and the electrodes, and an internal space is formed in a part of each of the insulating layers. The internal space may be formed only in the insulating layer disposed on the light-emitting element. The internal space may be formed only in the insulating layer disposed on the driving element. The internal space may be formed in both the insulating layer disposed on the light-emitting element and the driving element, respectively. The light-emitting element and the driving element may be joined to each other by wafer-on-wafer (WoW) technology. The light-emitting element and the driving element may be joined to each other by chip-on-wafer (CoW) technology. The light-emitting device may constitute a vertical-cavity surface-emitting laser (VCSEL). The light-emitting device may constitute a light-emitting diode (LED).Furthermore, this technology provides a distance measuring device equipped with the aforementioned light-emitting device. Furthermore, this technology provides electronic equipment equipped with the aforementioned distance measuring device.

[0008] Figure 5A is a schematic cross-sectional view showing an example of the configuration of a light-emitting element 1 according to one embodiment of this technology. Figure 6B is a schematic cross-sectional view showing an example of the configuration of a light-emitting element 1 according to one embodiment of this technology. Figure 7A is a schematic cross-sectional view showing an example of the configuration of a light-emitting element 1 according to one embodiment of this technology. Figure 7B is a schematic cross-sectional view showing an example of the configuration of a drive element 2 according to one embodiment of this technology. Figure 5A is a schematic top view showing the junction structure of the light-emitting element 1 and the drive element 2 according to one embodiment of this technology. Figure 5B is a schematic cross-sectional view along the line A-A' in Figure 5A. Figure 6A is a schematic top view showing the junction structure of the light-emitting element 1 and the drive element 2 according to one embodiment of this technology. Figure 6B is a schematic cross-sectional view along the line B-B' in Figure 6A. Figure 7A is a schematic top view showing an example of the configuration of a light-emitting element 1 according to one embodiment of this technology. Figure 7B is a schematic cross-sectionalA is a schematic top view showing an example of the configuration of a light-emitting element 1 according to one embodiment of this technology. This is a schematic cross-sectional view showing an example of the configuration of a light-emitting device 1000 according to one embodiment of this technology. This is a schematic cross-sectional view showing an example of the configuration of a light-emitting device 1000 according to one embodiment of this technology. This is a schematic perspective view showing an example of the configuration of a light-emitting device 1000 according to one embodiment of this technology. This is a schematic cross-sectional view along the line I-I in Figure 13. This is a schematic cross-sectional view showing a manufacturing method for a light-emitting device 1000 according to one embodiment of this technologyThis is a schematic cross-sectional view showing a manufacturing method for a light-emitting device 1000 according to one embodiment of this technology. This is a schematic cross-sectional view showing a manufacturing method for a light-emitting device 1000 according to one embodiment of this technology. This is a block diagram showing an example of the configuration of a distance measuring device 5000 according to one embodiment of this technology. This is a block diagram showing an example of the schematic configuration of a vehicle control system. This is an explanatory diagram showing an example of the installation position of the imaging unit.

[0009] Hereinafter, preferred embodiments for implementing this technology will be described with reference to the drawings. The embodiments described below are merely examples of typical embodiments of this technology and do not limit the scope of this technology. Furthermore, this technology can be implemented by combining any of the following embodiments and their modifications.

[0010] In the following description of embodiments, configurations may be described using terms with "approximately" attached, such as "approximately parallel" and "approximately orthogonal." For example, "approximately parallel" means not only that they are perfectly parallel, but also that they are substantially parallel, that is, that is, they are deviated from a perfectly parallel state by, for example, a few percent. The same applies to other terms with "approximately." Also, each figure is a schematic diagram and is not necessarily a strictly accurate representation. The scale of the drawings is exaggerated to make the technical features easier to understand. Therefore, it should be noted that the scale of the drawings and the scale of the actual device are not necessarily the same.

[0011] Unless otherwise specified, in drawings, "up" means the upper direction or upper side in the drawing, "down" means the lower direction or lower side in the drawing, "left" means the left direction or left side in the drawing, and "right" means the right direction or right side in the drawing. In addition, in drawings, the same or equivalent elements or components are denoted by the same reference numeral, and redundant explanations are omitted.

[0012] The embodiments described below represent typical embodiments of the Technology and should not be interpreted as narrowing the scope of the Technology. The effects described herein are illustrative and not limiting, and other effects may also exist.

[0013] The explanation will proceed in the following order: 1. First embodiment of this technology (Example 1 of a light-emitting element) (1) Overall configuration (2) Insulating layer 2. Second embodiment of this technology (Example 2 of a light-emitting element) 3. Third embodiment of this technology (Example of a driving element) 4. Fourth embodiment of this technology (Example 1 of a light-emitting device) (1) Overall configuration (2) Simulation 5. Fifth embodiment of this technology (Example 2 of a light-emitting device) 6. Sixth embodiment of this technology (Example 3 of a light-emitting device) 7. Seventh embodiment of this technology (Example 4 of a light-emitting device) 8. Eighth embodiment of this technology (Example 3 of a light-emitting element) 9. Ninth embodiment of this technology (Example of a method for manufacturing a light-emitting device) 10. Tenth embodiment of this technology (Example of a distance measuring device) 11. Eleventh embodiment of this technology (Example of an electronic device)

[0014] [1. First Embodiment of the Technology (Example 1 of a Light-Emitting Device)] [(1) Overall Configuration] The technology provides a light-emitting device having a plurality of light-emitting mesa portions, with an insulating layer disposed between each of the mesa portions, and an internal space formed in a part of each of the insulating layers. This suppresses wafer warping and facilitates bonding of the light-emitting device and the driving element.

[0015] An example of the configuration of a light-emitting element relating to this technology will be described with reference to Figure 1. Figure 1 is a schematic cross-sectional view showing an example of the configuration of a light-emitting element 1 according to one embodiment of this technology. This figure shows an example of the configuration of a light-emitting element used in a vertical-cavity surface-emitting laser (VCSEL), which is an example of a light-emitting device relating to this technology.

[0016] In this configuration example, the substrate 10 is designed so that its front surface (light-emitting surface) 10S faces the positive Z direction, and its back surface faces the negative Z direction. The substrate 10 functions as a physical support and growth substrate for constructing light-emitting elements. For example, GaAs (gallium arsenide) is used for the substrate 10. In addition to GaAs, materials such as InP, SiC, and sapphire may also be used as substrates.

[0017] Multiple light-emitting mesa portions 41 are formed on the substrate 10. The sides of the mesa portions 41 are made of SiO ２It is covered with an insulating film 42 such as SiN. The mesa portion 41 is the light source portion of the light-emitting element 1 and has a structure that protrudes from the substrate 10. The mesa structure forms a resonant space, which can increase the directivity and output of the light-emitting element.

[0018] The mesa portion 41 is formed by etching a part of the semiconductor laminate 12. The semiconductor laminate 12 is constructed by stacking the following layers in order, for example: the second constituent layer of the first reflector, the first current injection layer, the first constituent layer of the first reflector, the first cladding layer, the active layer, the second cladding layer, the first constituent layer of the second reflector, the second current injection layer, and the second constituent layer of the second reflector are epitaxially grown at, for example, 605 degrees to produce the semiconductor laminate 12.

[0019] The active layer structure employs, for example, a quantum well structure, which optimizes light generation efficiency and wavelength control. This quantum well structure plays a crucial role in increasing the efficiency of electron-hole recombination and achieving emission in a specific wavelength range.

[0020] The height of each mesa portion 41 is preferably 2 μm or more. This is because the height of the mesa portion 41 affects the luminous efficiency and directivity of the light. Increasing the height of the mesa portion 41 improves the resonance effect of the light, and increases the overall output of the light-emitting element 1.

[0021] The seed layer 43 is a layer formed by thinly depositing a metal such as titanium-copper alloy (Ti / Cu) onto the substrate surface using methods such as vapor deposition or sputtering, and functions as a base for electrodes and wiring. The seed layer 43 serves as a base for subsequent electrode and wiring formation, and provides a conductive path in the plating process. The seed layer 43 has the function of improving electrical conductivity, ensuring reliable connections between electrodes, and improving electrode adhesion.

[0022] The electrode 19 is formed using a metal such as copper (Cu) or titanium-copper alloy (Ti / Cu). The electrode 19 is placed on the surface of the mesa portion 41 and is wired to the semiconductor laminate 12 via the seed layer 43.

[0023] Electrode 19 is either an anode or a cathode electrode. The anode electrode is the positive electrode that supplies current. The anode electrode plays a role in the operation of the light-emitting element 1 by causing electrons to recombine with holes, thereby generating light. The cathode electrode functions as a negative electrode and receives current from the driving element (not shown in this figure). The cathode electrode is used as a ground terminal to form a current path and ensure the circulation of current.

[0024] In the manufacturing of VCSELs using this technology, the electrode-side end of the light-emitting element 1 and the driving element are joined via a bonding surface 17. However, warping may occur in the light-emitting element 1 during bonding, which can lead to a decrease in bonding quality and malfunctions in the entire manufacturing process. The main causes of warping are described below.

[0025] An insulating layer 18 is placed between each mesa portion 41. The insulating layer 18 is made of SiO ２ It is formed from inorganic insulating materials such as SiN and plays a role in ensuring electrical insulation between the mesa portions 41. This insulating layer 18 is formed by CVD (chemical vapor deposition) or sputtering, but residual stress accumulates during material condensation and cooling in these processes. This intrinsic film stress remains even after bonding, generating bending force throughout the wafer.

[0026] Furthermore, the electrode 19 is made up of a metal such as Cu, and the insulating layer 18 is made up of SiO ２ There are differences in the coefficient of thermal expansion (CTE) between these materials. As the temperature changes, each material expands and contracts at different rates, causing stress to accumulate and resulting in bending stress throughout the wafer.

[0027] Such stress accumulation can cause a portion of the bonding surface 17 to lift, potentially leading to bonding failures and a decrease in device performance. Furthermore, if dicing is performed while warping remains, cracks and fissures may form in the substrate 10, significantly reducing the product yield.

[0028] [(2) Insulating Layer] Therefore, in this technology, in order to effectively reduce the film stress inherent in the insulating layer 18 and the stress caused by the mismatch in the coefficient of thermal expansion between different materials, an internal space (void) 4 is formed in a part of the insulating layer 18. By providing this internal space 4, the film stress can be dispersed, and the stress accompanying temperature changes can be absorbed within the internal space 4. The larger the volume of the internal space 4, the greater the stress relaxation effect, the warping is suppressed, and the entire wafer is kept flat, thereby improving the adhesion of the bonding surface 17.

[0029] When the insulating layer 18 is continuously filled as in the prior art, the film stress propagates in one direction, and this applies bending stress to the entire wafer, resulting in warping. However, in this technology, by providing the internal space 4 within the insulating layer 18, the continuity of the insulating layer 18 is partially interrupted, and the rigidity of the entire insulating layer 18 is reduced. As a result, the stress is more likely to be locally released, and the warping generated during bonding is suppressed.

[0030] In addition, the insulating layer 18 having the internal space 4 can flexibly respond to the pressure and external force applied to the bonding surface 17 because it allows slight structural deformation during bonding. Thereby, not only the warping during bonding but also the bonding misalignment and peeling due to external force can be prevented.

[0031] Also, since the expansion and contraction of the material accompanying temperature changes are more likely to be absorbed within the internal space 4, the expansion stress is less likely to be transmitted to other layers. For example, when materials with significantly different coefficients of thermal expansion, such as Cu and SiO ２ are adjacent, the internal space 4 provides a buffering effect, and the stress due to the expansion of copper is absorbed within the internal space 4, suppressing the warping of the entire wafer.

[0032] Here, the internal space 4 may be formed in a part of the insulating layer 18, but it is preferable that the internal space 4 is formed in all of the insulating layers 18. By forming the internal space 4 in all of the insulating layers 18, the film stress accumulated in the insulating layer 18 can be more evenly dispersed. As a result, the warping during bonding is significantly reduced, the flatness of the bonding surface 17 is improved, and the bonding strength is ensured. Also, by providing the internal space 4 in all of the insulating layers 18, local stress concentration is prevented, and the risk of cracks and peeling is reduced.

[0033] Also, by providing the internal space 4 in all the insulating layers 18, it is possible to expect a reduction in manufacturing cost in the processing process. This is due to the fact that a plurality of different manufacturing processes can be processed collectively, resulting in improved manufacturing efficiency and ultimately achieving a high yield of the device.

[0034] Regarding the thickness of the insulating layer 18, it is preferable that the thickness A of the insulating layer 18 located on the outer periphery of the light-emitting element 1 is larger than the thickness B of the insulating layer 18 located on the inner periphery. With this configuration, the mechanical stress applied to the outer periphery is effectively absorbed, improving the durability of the entire device. Also, since the mechanical stress generated during the dicing process and operation concentrates on the outer periphery and the load applied to the inner periphery is reduced, an effect of particularly suppressing the occurrence of cracks and peeling in the inner periphery is obtained.

[0035] Furthermore, by strengthening the outer periphery, there is an effect of protecting the device from physical damage that occurs during dicing and assembly. By increasing the thickness of the insulating layer 18 around the outer periphery, the reliability of the entire device is improved. As a result, not only the suppression of crack generation but also the extension of the device life and the improvement of durability are contributed.

[0036] In addition, by increasing the thickness of the insulating layer 18 around the outer periphery, the electrical insulation performance is also improved, reducing the influence of interference and electrical noise from outside the device. Thereby, stable operation of the light-emitting element 1 is realized and the overall device performance is improved.

[0037] The thickness of the insulating layer 18 covering the mesa portion 41 is preferably 1μm or more. With this configuration, the electrical insulation of the mesa portion 41 is ensured, and an effect of preventing a short circuit between adjacent mesa portions 41 is obtained. Also, by providing a sufficient thickness of the insulating layer 18, the durability of the mesa portion 41 is improved, and the mesa portion 41 can be protected from mechanical stress from the outside and stress due to temperature change.

[0038] Furthermore, by setting the thickness of the insulating layer 18 to 1 μm or more, voltage resistance is enhanced, making it possible to ensure reliability even when operating at high voltages. In particular, in high-voltage driving environments for the light-emitting element 1, an insulating layer 18 of sufficient thickness is essential, which prevents damage to the element and performance degradation.

[0039] In addition, increasing the thickness to 1 μm or more improves the corrosion resistance of the mesa portion 41, reducing the effects of external environmental factors such as moisture and oxidation. This improves the long-term reliability and durability of the device, extending the product lifespan.

[0040] It is preferable that the thickness A of the insulating layer 18 covering the area opposite to the end (joint surface 17) of the mesa portion 41 (the substrate 10 side) is greater than the thickness C of the insulating layer 18 covering the end. In other words, it is preferable that the shape of the internal space 4 in cross-sectional view is tapered.

[0041] One advantage of this tapered shape is that it can suppress crack propagation at corners where stress tends to concentrate during temperature changes. When materials expand and contract due to temperature changes, stress tends to concentrate at corners.

[0042] In this technology, by employing a tapered shape, these stresses are relieved without concentrating at the corners, resulting in a reduced risk of crack formation.

[0043] A polymer material may be used as the material for the insulating layer 18. This configuration allows for the effective absorption and dispersion of stress generated within the insulating layer 18, taking advantage of the flexibility and low film stress properties of the polymer material. In particular, polymer materials have a relatively high coefficient of thermal expansion but low rigidity, and can flexibly respond to temperature changes. Therefore, they not only function as an insulating layer 18 but are also expected to prevent cracks and delamination caused by thermal expansion and contraction.

[0044] Furthermore, polymer materials have a simple film deposition process and can be manufactured using low-temperature processes. This improves the manufacturing efficiency of the light-emitting element 1 and reduces costs.

[0045] Furthermore, polymer materials also possess excellent electrical insulation properties, preventing electrical interference and noise. Therefore, even in high-density mounting and narrow-pitch connections, the use of polymer materials ensures stable operation and improves the reliability of the light-emitting element 1.

[0046] Examples of polymer materials include thermosetting resins such as polyimide and epoxy resins, or thermoplastic resins such as polyethylene and polypropylene.

[0047] The above description of the light-emitting element according to the first embodiment of this technology can be applied to other embodiments of this technology, unless there are any particular technical inconsistencies.

[0048] [2. Second Embodiment of the Technology (Example 2 of a Light-Emitting Device)] An example of the configuration of a light-emitting device 1 according to another embodiment of the Technology will be described with reference to Figure 2. Figure 2 is a schematic cross-sectional view showing an example of the configuration of a light-emitting device 1 according to one embodiment of the Technology.

[0049] As shown in Figure 2, the internal space may be filled with an insulating material 44 different from the material of the insulating layer 18. When the insulating material 44 is filled, the function of the insulating layer 18 is enhanced, and the electrical insulation is further improved, ensuring stable performance even during high-voltage operation. In addition, the filling with the insulating material 44 makes the device less susceptible to external environmental influences, improving the overall durability and reliability of the device.

[0050] The insulating material used to fill the internal space is preferably one that can effectively disperse film stress. In particular, the insulating layer 18 itself is preferably made of SiO ２ If it is composed of the same SiO, the insulating material 44 to be filled will also be the same SiO ２ Using this method may result in insufficient stress relaxation. Therefore, it is desirable to select a different material for the insulating material 44 than the insulating layer 18.

[0051] By using, for example, a polymer material or a flexible insulating material as the insulating material 44, film stress can be efficiently absorbed and dispersed, preventing stress concentration due to differences in thermal expansion. This suppresses warping and crack formation of the entire device, enabling stable operation over the long term.

[0052] Furthermore, flexible materials such as polymers can flexibly respond to temperature changes and mechanical stress, improving the physical strength of the mesa portion 41 and surrounding structures while maintaining insulation performance. As a result, the reliability and durability of the device are improved, and it is expected to exhibit excellent performance in various environments.

[0053] The above description of the light-emitting element according to the second embodiment of this technology can be applied to other embodiments of this technology, unless there are any particular technical inconsistencies.

[0054] [3. Third Embodiment of the Technology (Example of a Driving Element)] The technology provides a driving element having a plurality of electrodes electrically connected to each of a plurality of mesa portions of a light-emitting element, for driving the light-emitting element, with an insulating layer disposed between each of the electrodes, and an internal space formed in a part of each of the insulating layers.

[0055] An example of the configuration of the driving element relating to this technology will be explained with reference to Figure 3. Figure 3 is a schematic cross-sectional view showing an example of the configuration of a driving element 2 according to one embodiment of this technology. This figure shows an example of the configuration of a driving element used in a VCSEL (Vertical Cavity Surface Emitting Laser), which is an example of a light-emitting device relating to this technology.

[0056] As shown in Figure 3, the driving element 2 is electrically connected to each of the multiple mesa portions of the light-emitting element (not shown in this figure) and has multiple electrodes 22 for driving the light-emitting element.

[0057] The electrode 22 is formed using a metal such as copper (Cu) or titanium-copper alloy (Ti / Cu). The electrode 22 is placed on the surface of the drive element 2 and wired via the seed layer 23.

[0058] Switch 24 controls the current from the driving element 2 to the light-emitting element 1, thereby controlling the timing of light emission. Switch 24 is connected to the driving circuit of the light-emitting element 1 and adjusts the interval and intensity of the light emission pulses. Switch 24 enables short-pulse control on the order of hundreds of picoseconds, for example, in applications where instantaneous light emission is required, such as facial recognition in smartphones or AR devices.

[0059] An insulating layer 21 is placed between each electrode 22. An internal space 4 is formed in a portion of each insulating layer 21. By providing this internal space 4, film stress can be dispersed and stress due to temperature changes can be absorbed within the internal space 4. The larger the volume of the internal space 4, the greater the stress relaxation effect, the more warping is suppressed, and the flatter the entire wafer is kept, thereby improving the adhesion of the bonding surface 17.

[0060] While an internal space 4 may be formed in a portion of the insulating layer 21, it is preferable that the internal space 4 be formed in the entire insulating layer 21. By forming the internal space 4 in the entire insulating layer 21, the film stress accumulated within the insulating layer 21 can be distributed more evenly. As a result, warping during joining is significantly reduced, and the flatness of the joining surface 17 is improved, thus ensuring joining strength. In addition, by providing the internal space 4 in the entire insulating layer 21, localized stress concentration is prevented, reducing the risk of cracks and delamination.

[0061] Furthermore, by providing internal spaces 4 in all insulating layers 21, a reduction in manufacturing costs during the processing stage can be expected. This is because multiple different manufacturing processes can be handled simultaneously, improving manufacturing efficiency and ultimately achieving a high yield for the devices.

[0062] The above description of the driving element according to the third embodiment of this technology can be applied to other embodiments of this technology unless there are any particular technical inconsistencies.

[0063] [4. Fourth Embodiment of the Technology (Example 1 of Light-Emitting Device)] [(1) Overall Configuration] The technology provides a light-emitting device comprising: a light-emitting element having a plurality of mesa portions; and a driving element electrically connected to each of the plurality of mesa portions and having a plurality of electrodes for driving the light-emitting element, wherein an insulating layer is disposed between each of the mesa portions and the electrodes, and an internal space is formed in a part of each of the insulating layers.

[0064] An example of the configuration of a light-emitting device relating to this technology will be described with reference to Figure 4. Figure 4 is a schematic cross-sectional view showing an example of the configuration of a light-emitting device 1000 according to one embodiment of this technology. This light-emitting device 1000 constitutes an example of a vertical-cavity surface-emitting laser (VCSEL). The light-emitting device 1000 emits light from the light-emitting surface 10S in the positive direction of the Z axis.

[0065] The light-emitting device 1000 comprises a light-emitting element 1 and a driving element 2. The light-emitting element 1 and the driving element 2 are bonded to each other using wafer-on-wafer (WoW) technology. WoW technology is a technique for bonding two wafers, namely the wafer on which the light-emitting element 1 is formed and the wafer on which the driving element 2 is formed, with high precision alignment. This technology allows for the bonding of elements individually formed on both wafers in a single process, and by dicing (fragmentation), the final light-emitting device 1000 can be obtained.

[0066] One example of a method for bonding a light-emitting element wafer and a drive element wafer is plasma bonding. Plasma bonding involves forming SiO on the bonding surface of the semiconductor wafer. ２ By irradiating a layer consisting of the above materials with plasma, silanol groups (Si-OH groups) are formed. Then, the surfaces with the silanol groups are placed facing each other, and a portion of the semiconductor substrate is pressed against them to bond them by van der Waals forces. Subsequently, to further enhance the adhesion force of the bonding interface, a heat treatment of, for example, 400°C / 60 min is applied, causing a dehydration condensation reaction between the silanol groups, promoting thermal diffusion between the electrodes (Cu) of the light-emitting element wafer and the drive element wafer, resulting in ohmic contact between the electrodes and completing the wafer bonding.

[0067] This ensures the stability of the electrical connection between the light-emitting element 1 and the driving element 2, and enables high-density and narrow-pitch connections at the bonding surface 17. In particular, it enables connections with a pitch of 5 μm or less, realizing further miniaturization and performance improvement of the light-emitting device 1000.

[0068] Currently, in the structure of light-emitting devices (e.g., VCSELs) available on the market, the pitch between elements is generally around 20 μm to 30 μm. This pitch indicates the density of element placement, and a higher density of light-emitting points results in the formation of a finer light-emitting pattern. As a result, the high density of light-emitting points improves screen resolution, and this is applied to high-precision applications such as facial recognition in smartphones.

[0069] Furthermore, when using a light-emitting element that emits laser light, the capacitance component (parasitic capacitance) and wiring inductance that parasitize the pad portion of the wiring in the drive circuit become sources of electrical noise. This noise causes signal delay and pulse degradation, and the delay in the light emission pulse reduces the overall performance of the light-emitting device 1000. In addition, the peak of the light emission pulse decreases and the emission time is prolonged, which worsens the signal-to-noise ratio (S / N ratio) when the light that has been irradiated onto the target returns.

[0070] This technology enables direct wiring of the light-emitting element 1 and the driving element 2, as well as miniaturization of the pads, thereby reducing the impedance and parasitic capacitance within the circuit. This suppresses the delay of the light-emitting pulse, enabling ultra-high-speed pulse control from a few nanoseconds to several hundred picoseconds, for example, and contributing to improved power efficiency. Furthermore, by reducing the loop inductance of the entire circuit, power efficiency for short pulses is further improved, and the light-emitting device 1000 itself can be miniaturized.

[0071] The solder balls 45 are electrical and physical connection points for connecting the drive element 2 to the external substrate. Multiple solder balls 45 are connected during the reflow process and are responsible for signal transmission between the electrode 22 and the external circuit. To achieve high-density mounting, it is preferable to use small-diameter solder balls 45.

[0072] The light-emitting element 1 has a plurality of mesa portions 41. The driving element 2 is electrically connected to each of the plurality of mesa portions 41 and has a plurality of electrodes 22 for driving the light-emitting element 1.

[0073] Insulating layers 18 and 21 are placed between each mesa portion 41 and electrode 22. An internal space 4 is formed in a portion of each insulating layer 18 and 21. In this configuration example, the internal space 4 is formed in both the insulating layers 18 and 21 placed on the light-emitting element 1 and the driving element 2, respectively. This makes it possible to suppress warping during bonding, as described above.

[0074] The joining of the light-emitting element 1 and the driving element 2 will be further explained with reference to Figures 5 and 6. Figure 5A is a schematic top view showing the joining structure of the light-emitting element 1 and the driving element 2 according to one embodiment of this technology. Figure 5B is a schematic cross-sectional view along the line A-A' in Figure 5A.

[0075] As shown in Figure 5A, each light-emitting element and driving element are arranged in a grid pattern. An insulating layer is placed around the outer periphery of the electrode 19. This structure ensures that each electrode 19 is insulated while maintaining electrical connection.

[0076] In Figure 5B, the light-emitting element 1 and the driving element 2 are stacked and joined vertically, and an internal space 4 is formed in the insulating layers 18 and 21. This distributes stress due to film stress and thermal expansion differences, suppressing wafer warping. In addition, copper fusion bonding is performed between the electrodes of the light-emitting element and the driving element, forming a strong ohmic connection.

[0077] Figure 5 shows a state where the bonding alignment of the wafer on which the light-emitting element 1 is formed and the wafer on which the driving element 2 is formed is precisely matched. Both wafers are precisely aligned based on their respective alignment marks. This alignment technology ensures the accuracy of the overlapping of the upper and lower wafers after bonding, thereby preventing bonding defects.

[0078] In wafer bonding, transmitted light such as IR (infrared) is used to measure the misalignment of alignment marks engraved on the upper and lower wafers at multiple locations. This misalignment is generally called the total overlay and serves as an indicator for evaluating bonding accuracy. The total overlay is usually evaluated by decomposing it into the following four parameters.

[0079] Translation indicates the relative parallel displacement (X-axis direction) between the upper and lower wafers. Scaling indicates the relative expansion and contraction component between the upper and lower wafers, also known as run-out or expansion. Rotation indicates the rotational component between the upper and lower wafers. Residual is a random element that cannot be corrected by the above three scalar factors (Translation, Scaling, Rotation), and is caused by the bonding process and inherent distortion of the wafer.

[0080] These components are primarily corrected by the wafer bonding equipment, but residual random components are treated as distortion components in the lithography process. Residual components arise from multiple factors, including wafer-specific localized stress and strain caused by wafer-to-wafer bonding during the bonding process between wafers. In the wafer manufacturing and bonding processes, corrections are made to minimize these deviations and strains, thereby improving the final bonding accuracy.

[0081] On the other hand, Figure 6 shows a state in which an alignment misalignment occurs in the X-axis direction at the junction of the light-emitting element 1 and the driving element 2. Figure 6A is a schematic top view showing the junction structure of the light-emitting element 1 and the driving element 2 according to one embodiment of this technology. Figure 6B is a schematic cross-sectional view along the line B-B' in Figure 6A.

[0082] If alignment misalignment occurs, there is a risk of electrical connection failure between the light-emitting element 1 and the driving element 2, or a decrease in bonding strength. Note that in this figure, the alignment misalignment is depicted in an exaggerated manner compared to the actual state, but the alignment accuracy in actual wafer bonding equipment is very high. The alignment accuracy of a typical bonding equipment is approximately 130 nm in total overlay (3σ).

[0083] [(2) Simulation] In order to achieve high-precision bonding of the light-emitting element and the driving element, it is preferable to keep the amount of warpage to 100 μm or less on a 12-inch wafer, and more preferably to keep it to 70 μm or less.

[0084] To achieve this amount of warping, the light-emitting element 1 shown in Figure 7 was designed, and the amount of warping was estimated by simulation. Figure 7A is a schematic top view showing an example of the configuration of the light-emitting element 1 according to one embodiment of this technology. Figure 7B is a schematic cross-sectional view showing an example of the configuration of the light-emitting element 1 according to one embodiment of this technology.

[0085] As shown in Figure 7A, the pitch P of the electrodes 19 (the distance between the centers of each electrode 19) was 15 μm, the diameter D of the electrodes 19 was Φ5 μm, the spacing I of the insulating layers 18 (the distance between adjacent insulating layers 18) was 6 μm, and the width W of the insulating layers 18 was 2 μm. Also, as shown in Figure 7B, the thickness T of the insulating layer 18 in the thickness direction of the substrate 10 was set to 2 μm, and the height H of the mesa portion 41 was changed from 2 μm to 6 μm.

[0086] Figure 8 is a graph showing the simulation results of wafer warpage of a light-emitting element 1 according to one embodiment of this technology. The horizontal axis represents the height of the mesa portion, and the vertical axis represents the warpage of a 12-inch wafer. Two conditions are compared: before and after the formation of the internal space. This graph shows how the wafer warpage changes as the height of the mesa portion increases.

[0087] The dashed line represents the amount of wafer warpage before the formation of the internal space, and it can be seen that the amount of warpage increases proportionally as the height of the mesa increases.

[0088] On the other hand, the solid line shows the amount of warping after the formation of the internal space, and it can be seen that the amount of wafer warping has been significantly reduced. The amount of wafer warping after the formation of the internal space remains within a nearly constant range even when the height of the mesa increases, and is kept to about 60 to 80 μm. This result indicates that film stress is effectively reduced by the formation of the internal space, and wafer warping can be suppressed.

[0089] The above description of the light-emitting device according to the fourth embodiment of this technology can be applied to other embodiments of this technology, unless there are any particular technical inconsistencies.

[0090] [5. Fifth Embodiment of the Technology (Example 2 of Light-Emitting Device)] In the fourth embodiment, internal spaces 4 are formed in both the insulating layers 18 and 21, which are respectively arranged in the light-emitting element 1 and the driving element 2. However, internal spaces 4 may be formed in only one of the light-emitting element 1 and the driving element 2. This will be explained with reference to Figures 9 and 10. Figures 9 and 10 are schematic cross-sectional views showing an example configuration of a light-emitting device 1000 according to one embodiment of the Technology.

[0091] As shown in Figure 9, the internal space 4 may be formed only in the insulating layer 18 located on the light-emitting element 1. In this configuration example, the internal space is not formed in the insulating layer 21 located on the driving element 2.

[0092] Alternatively, as shown in Figure 10, the internal space 4 may be formed only in the insulating layer 21 located on the driving element 2. In this configuration example, the insulating layer 18 located on the light-emitting element 1 does not have an internal space.

[0093] Even if the internal space 4 is formed in only one of the light-emitting element 1 or the driving element 2, the stress absorption effect of the internal space is still exerted, reducing the risk of warping and cracking of the entire device.

[0094] Furthermore, even in configurations where the internal space is formed on only one side, sufficient strength of the joint surface can be ensured while simplifying the manufacturing process and reducing costs. This improves manufacturing efficiency and enhances the long-term reliability and performance of the light-emitting device 1000.

[0095] The above content described for the light-emitting device according to the fifth embodiment of the present technology can be applied to other embodiments of the present technology as long as there is no particular technical contradiction.

[0096] [6. Sixth Embodiment of the Present Technology (Example 3 of Light-Emitting Device)] A configuration example of the light-emitting device 1000 according to another embodiment of the present technology will be described while referring to FIG. 11. FIG. 11 is a schematic cross-sectional view showing a configuration example of the light-emitting device 1000 according to an embodiment of the present technology.

[0097] As shown in FIG. 11, an insulating material 44 different from the material of the insulating layer 18 may be filled in the internal space. When the insulating material 44 is filled, the function as the insulating layer 18 is strengthened and the electrical insulation is further improved, so that stable performance is ensured even in high-voltage operation. In addition, by filling the insulating material 44, it becomes less susceptible to the influence of the external environment, and the durability and reliability of the entire device are improved.

[0098] As the insulating material filled in the internal space, it is preferable to use a material that can effectively disperse film stress. In particular, when the insulating layer 18 itself is composed of, for example, SiO ２ If the same SiO ２ is also used as the insulating material 44 to be filled, there is a possibility that the stress relaxation effect cannot be sufficiently obtained. Therefore, it is desirable to select a low-stress material different from the insulating layer 18 as the insulating material 44.

[0099] By using, for example, a polymer material or a flexible insulating material as the insulating material 44, film stress can be efficiently absorbed and dispersed, and stress concentration due to the difference in thermal expansion can be prevented. As a result, warping and crack generation of the entire device are suppressed, and stable operation over a long period is possible.

[0100] In addition, a flexible material such as a polymer material can flexibly respond to temperature changes and mechanical stresses, and has the effect of improving the physical strength of the mesa portion 41 and the peripheral structure while maintaining the insulation performance. As a result, the reliability and durability of the device are improved, and it is expected to exhibit excellent performance in various environments.

[0101] The above description of the light-emitting device according to the sixth embodiment of this technology can be applied to other embodiments of this technology, unless there are any particular technical inconsistencies.

[0102] [7. Seventh Embodiment of the Technology (Example 4 of the Light-Emitting Device)] An example of the configuration of a light-emitting device relating to the Technology will be described with reference to Figure 12. Figure 12 is a schematic cross-sectional view showing an example of the configuration of a light-emitting device 1000 according to one embodiment of the Technology. This light-emitting device 1000 constitutes an example of a vertical-cavity surface-emitting laser (VCSEL).

[0103] The light-emitting device 1000 comprises a light-emitting element 1 and a driving element 2. The light-emitting element 1 and the driving element 2 are bonded to each other using chip-on-wafer (CoW) technology.

[0104] CoW technology is a method of bonding individually diced semiconductor chips onto another wafer using WoW technology. This technology makes it possible to arrange and electrically connect multiple chips with high precision.

[0105] In CoW technology, semiconductor chips including the light-emitting element 1 are first individually cut (diced), then mounted on a support wafer using a flip-chip mounting method or the like to create a pseudo-wafer state, and the light-emitting element 1 and the driving element 2 are electrically connected using WoW technology. By using CoW technology, individually optimized light-emitting element 1 and driving element 2 are manufactured independently and then joined together, each process can be optimized.

[0106] The light-emitting element 1 has a layered structure that includes an active layer in which electrons and holes recombine to generate light, and the light generated within this structure is emitted outwards. An electrode 19 is formed at the bottom of the light-emitting element 1 for electrical connection with the driving element 2. This electrode 19 is electrically connected by contacting the electrode 22 of the driving element 2, and power is supplied to the light-emitting element 1 and its operation is controlled. The driving element 2 has an electrical circuit (not shown) built in for driving the light-emitting element 1 and plays a role in adjusting the accuracy and timing of light emission.

[0107] An internal space 4 is formed in a portion of the insulating layers 18 and 21, which disperses film stress and has the effect of mitigating stress caused by thermal expansion during bonding. This structure suppresses wafer warping during bonding, and significantly improves the overall stability and reliability of the light-emitting device 1000.

[0108] The light-emitting element 1 and the driving element 2 are connected to the external circuit 47 by the wire 46. Wire bonding is a technique in semiconductor devices that electrically connects the electrode pads of a semiconductor chip to a substrate or other devices using very thin metal wires. Conductive metals such as gold (Au), silver (Ag), and copper (Cu) are mainly used as the wire 46 and are used to achieve an electrical connection from the chip to the substrate.

[0109] CoW technology allows the light-emitting element 1 to be directly mounted as an individual chip on the wafer of the drive element 2. This technology enables high-precision arrangement and bonding of multiple light-emitting elements 1, improving the reliability of the electrical connection between the light-emitting elements 1 and the drive element 2. Furthermore, the internal spaces 4 formed in the insulating layers 18 and 21 suppress film stress and prevent warping during bonding, resulting in a significant improvement in the long-term reliability and performance of the entire light-emitting device 1000.

[0110] The above description of the light-emitting device according to the seventh embodiment of this technology can be applied to other embodiments of this technology, unless there are any particular technical inconsistencies.

[0111] [8. Eighth Embodiment of the Technology (Example 3 of Light-Emitting Devices)] The technology can be applied not only to VCSELs but also to light-emitting diodes (LEDs) and the like. This will be explained with reference to Figures 13 and 14. Figure 13 is a schematic perspective view showing an example of the configuration of a light-emitting device 1000 according to one embodiment of the technology. Figure 14 is a schematic cross-sectional view taken along the line I-I in Figure 13. The light-emitting device 1 of this light-emitting device 1000 constitutes a light-emitting diode (LED), which is an example of a light-emitting device.

[0112] The light-emitting device 1000 may be a so-called LED display, for example, used as an image display device. As shown in Figure 13, the light-emitting device 1000 has a display area 1A in its central part, and a non-display area, the frame area 1B, is formed around the display area 1A.

[0113] As shown in Figure 14, the light-emitting device 1000 comprises a light-emitting element 1 and a driving element 2. The light-emitting element 1 and the driving element 2 are joined to each other using wafer-on-wafer (WoW) technology. This structure improves the connection efficiency between the light-emitting element 1 and the driving element 2, resulting in a more compact and higher-performing overall device.

[0114] The light-emitting element 1 is provided with a semiconductor laminate 12 that constitutes a plurality of light-emitting parts. A color conversion layer 30 is arranged above the semiconductor laminate 12. This color conversion layer 30 includes a red color conversion layer 31, a green color conversion layer 32, and a blue color conversion layer 33. Preferably, a light-shielding portion 34 is formed between these color conversion layers. The light-shielding portion 34 functions to reduce color mixing between adjacent pixels and plays a role in improving the display quality of the image display device.

[0115] In this embodiment, the light-emitting element 1 is formed by first growing the semiconductor layers (first conductivity type layer 13, active layer 14, and second conductivity type layer 15) that constitute the semiconductor laminate 12, and then forming insulating layers 18 and 22.

[0116] The semiconductor laminate 12 has a configuration in which a first conductivity layer 13, an active layer 14, and a second conductivity layer 15 are stacked in this order, and has, for example, a columnar shape. The first conductivity layer 13, the active layer 14, and the second conductivity layer 15 are composed of, for example, InGaN-based semiconductor materials or AlGaInP-based semiconductor materials. The first conductivity layer 13 can be formed, for example, from a silicon (Si)-doped GaN layer. The active layer 14 can be formed, for example, from an InGaN layer. The second conductivity layer 15 can be formed, for example, from a magnesium (Mg)-doped GaN layer.

[0117] The semiconductor layer 11, the first conductivity layer 13, the active layer 14, and the second conductivity layer 15 can be formed by epitaxial crystal growth using methods such as metal-organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE).

[0118] The insulating layers 18 and 22 electrically isolate the multiple light-emitting parts and are arranged in a grid pattern on the semiconductor layer 11, for example. The insulating layers 18 and 22 can be formed using dielectric materials or insulating materials such as oxide materials or nitride materials. Specifically, the insulating layers 18 and 22 can be made of silicon oxide (SiO2), for example. ２ It can be formed using materials such as silicon nitride (SiN).

[0119] An internal space 4 is formed in a portion of the insulating layers 18 and 22. By providing this internal space 4, film stress can be dispersed and stress due to temperature changes can be absorbed within the internal space 4. As a result, warping is suppressed and the adhesion of the joint surface is improved.

[0120] Other components may be the same as those shown in Figure 4, so their explanation will be omitted.

[0121] The above description of the light-emitting element according to the eighth embodiment of this technology can be applied to other embodiments of this technology, unless there are any particular technical inconsistencies.

[0122] [9. Ninth Embodiment of the Technology (Example of Method for Manufacturing a Light-Emitting Device)] The technology provides a method for manufacturing a light-emitting element, which includes forming a plurality of light-emitting mesa portions, arranging an insulating layer between each of the mesa portions, and forming an internal space in a part of each of the insulating layers.

[0123] Furthermore, this technology provides a method for manufacturing a driving element, which includes arranging a plurality of electrodes electrically connected to each of the plurality of mesa portions of the light-emitting element for driving the light-emitting element, arranging an insulating layer between each of the electrodes, and forming an internal space in a part of each of the insulating layers.

[0124] Furthermore, this technology provides a method for manufacturing a light-emitting device, which includes: forming a plurality of light-emitting mesa portions in a light-emitting element; arranging a first insulating layer between each of the mesa portions; forming a first internal space in a part of each of the first insulating layers; arranging a plurality of electrodes in a driving element that are electrically connected to each of the plurality of mesa portions of the light-emitting element and for driving the light-emitting element; arranging a second insulating layer between each of the electrodes; forming a second internal space in a part of each of the second insulating layers; and joining the light-emitting element and the driving element to each other.

[0125] A method for manufacturing the light-emitting device 1000 according to the fourth embodiment will be described with reference to Figures 15 to 26. Figures 15 to 26 are schematic cross-sectional views showing a method for manufacturing the light-emitting device 1000 according to one embodiment of this technology.

[0126] Figure 15 shows the process of forming the semiconductor laminate 12. First, the semiconductor laminate 12 is formed on the surface of the substrate 10 using methods such as metal-organic vapor deposition (MOCVD) or molecular beam epitaxy (MBE). This semiconductor laminate 12 is composed of the following layers stacked in order, for example: the second constituent layer of the first reflector, the first current injection layer, the first constituent layer of the first reflector, the first cladding layer, the active layer, the second cladding layer, the first constituent layer of the second reflector, the second current injection layer, and the second constituent layer of the second reflector. These layers are epitaxially grown, for example, at a growth temperature of 605°C to produce the semiconductor laminate 12.

[0127] During growth, trimethylgallium ((CH) is used as a raw material gas. ３ ) ３ Ga), trimethylaluminum ((CH ３ ) ３ Al), trimethylindium ((CH ３ ) ３ In), trimethylarsenide ((CH ３ ) ３ As is used. Monosilane (SiH) is used as a raw material gas for silicon. ４ ) and other carbon source gases include carbon tetrabromide (CBr). ４Use ) etc.

[0128] Next, in the light-emitting element 1, the surface of the semiconductor laminate 12 is etched to form a plurality of light-emitting mesa portions 41. In the etching process, for example, Cl ２ SiCl ４ Inductively Coupled Plasma (ICP) dry etching is performed using Ar or similar materials.

[0129] Subsequently, the sidewalls of the mesa portion 41 are coated with a SiN film or SiO ２ The material is covered with an insulating film 42, such as a film. However, the step of covering the side walls with an insulating film 42 may be omitted because an insulating layer will be formed in a later step.

[0130] Next, as shown in Figure 16A, a seed layer 43 is first formed on the upper surface of the light-emitting element 1 by a vapor deposition method or sputtering method to form electrodes. Similarly, a seed layer 23 is formed on the upper surface of the driving element 2 to form electrodes. Materials such as titanium copper alloy (Ti / Cu) can be used for the seed layers 43 and 23.

[0131] Next, as shown in Figure 17, a resist film 47 is applied, and patterning is performed by exposure and development to form a copper (Cu) film and electrodes 19 and 22 as connection pads. In the light-emitting element 1, a plurality of electrodes 19 are arranged to be electrically connected to each of the plurality of electrodes 22 of the driving element 2. In the driving element 2, a plurality of electrodes 22 are arranged to be electrically connected to each of the plurality of mesa portions 41 of the light-emitting element 1 for driving the light-emitting element 1.

[0132] Next, the resist film is removed as shown in Figure 18, and the seed layers 43 and 23 are etched as shown in Figure 19.

[0133] Next, as shown in Figure 20, a first insulating layer 18 is placed between each mesa portion 41, and a second insulating layer 21 is placed between each electrode 22. The first insulating layer 18 and the second insulating layer 21 are formed, for example, by chemical vapor deposition (CVD) to create a silicon oxide film (SiO₂). ２ It is formed from inorganic materials such as film, silicon nitride film (SiN film), and silicon carbide film (SiC film).

[0134] Next, as shown in Figure 21, the surfaces of the insulating layers 18 and 21 are flattened and thinned using CMP (Chemical Mechanical Polishing) to expose the upper surfaces of the electrodes 19 and 22.

[0135] Next, as shown in Figure 22, a resist film 47 is applied, and as shown in Figure 23, a portion of the insulating layers 18 and 21 is etched away. For example, SiO ２ For films, an etching solution containing hydrofluoric acid is used, and for SiN films, an etching solution containing hydrogen peroxide is used. In this way, a first internal space 4 is formed in a part of each first insulating layer 18. A second internal space 4 is formed in a part of each second insulating layer 21.

[0136] Next, the resist film 47 is removed as shown in Figure 24, and the light-emitting element 1 and the driving element 2 are joined to each other as shown in Figure 25. Wafer bonding is performed, for example, using a plasma bonding method. In this method, SiO ２ Plasma irradiation is applied to the layer to form silanol groups (Si-OH groups). Next, the surfaces with silanol groups are placed facing each other, and pressure is applied to bond them by van der Waals forces. Subsequently, heat treatment is performed at approximately 400°C for 60 minutes, causing a dehydration condensation reaction between the silanol groups, improving the adhesion of the bonded surfaces. At the same time, thermal diffusion of the Cu electrode progresses, forming ohmic contact, resulting in a highly reliable electrically connected bond.

[0137] Finally, as shown in Figure 26, solder balls 45 are mounted and the connection is completed by reflow soldering. In this way, the light-emitting device 1000 is manufactured.

[0138] The above description of the method for manufacturing a light-emitting device according to the ninth embodiment of this technology can be applied to other embodiments of this technology, unless there are any particular technical inconsistencies.

[0139] [10. Tenth Embodiment of the Technology (Example of a Distance Measuring Device)] The Technology provides a distance measuring device comprising a light-emitting element, a driving element, and a light-emitting device according to the first to eighth embodiments.

[0140] An example of the configuration of the distance measuring device according to this embodiment will be described with reference to Figure 27. Figure 27 is a block diagram showing an example of the configuration of a distance measuring device 5000 according to one embodiment of this technology.

[0141] As shown in Figure 27, the distance measuring device 5000 includes a light-emitting device 1000, an imaging device 2000, and a control device 3000.

[0142] The light-emitting device 1000 functions as a light source for the imaging device 2000 to image the subject 4000. The distance measuring device 5000 illuminates the subject 4000 with light emitted from the light-emitting device 1000, and the imaging device 2000 receives the light reflected from the subject 4000 to image the subject 4000. The control device 3000 measures (calculates) the distance to the subject 4000 using the image signal output from the imaging device 2000.

[0143] The light-emitting device 1000 includes a light-emitting unit 1001, a drive circuit 1002, a power supply circuit 1003, and a light-emitting optical system 1004. The imaging device 2000 includes an image sensor 2001, an image processing unit 2002, and an imaging optical system 2003, and the control device 3000 includes a distance measuring unit 3001.

[0144] The light-emitting unit 1001 emits laser light for irradiating the subject 4000. The light-emitting unit 1001 in this embodiment comprises, for example, a plurality of light-emitting elements arranged in a two-dimensional array, and each light-emitting element has, for example, a VCSEL structure. These light-emitting elements are provided within an LD (Laser Diode) chip 1005, and the emitted light is irradiated onto the subject 4000.

[0145] The drive circuit 1002 is an electrical circuit that drives the light-emitting unit 1001. The power supply circuit 1003 is an electrical circuit that generates the power supply voltage supplied to the drive circuit 1002. For example, the power supply circuit 1003 converts the input voltage supplied from the battery in the distance measuring device 5000, and the drive circuit 1002 uses that voltage to drive the light-emitting unit 1001. In this embodiment, the drive circuit 1002 is located within the LDD (Laser Diode Driver) substrate 1006.

[0146] The light-emitting optical system 1004 is equipped with various optical elements to accurately illuminate the subject 4000 with light from the light-emitting unit 1001. Similarly, the imaging optical system 2003 is equipped with optical elements to accurately receive reflected light from the subject 4000.

[0147] The image sensor 2001 receives light from the subject 4000 via the imaging optical system 2003, converts it into an electrical signal through photoelectric conversion. In this embodiment, a CCD (Charge Coupled Device) sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor is used. The image sensor 2001 converts the optical signal from an analog signal to a digital signal through A / D (Analog to Digital) conversion and outputs it to the image processing unit 2002.

[0148] Furthermore, the image sensor 2001 outputs a frame synchronization signal to the drive circuit 1002, and the drive circuit 1002 accurately drives the light-emitting unit 1001 in accordance with the frame period based on this synchronization signal. This adjusts the timing of light emission and improves the accuracy of distance measurement.

[0149] The image processing unit 2002 has the function of performing various image processing on the image signal output from the image sensor 2001, and is equipped with an image processing processor such as a DSP (Digital Signal Processor).

[0150] The control device 3000 controls the overall operation of the distance measuring device 5000, and controls the illumination of the light-emitting device 1000 and the imaging of the imaging device 2000. The control device 3000 includes a CPU (Central Processing Unit), ROM (Read-Only Memory), RAM (Random Access Memory), etc.

[0151] The distance measuring unit 3001 measures the distance to the subject 4000 using the results of the image processing unit 2002 based on the signal output from the image sensor 2001. The distance measuring unit 3001 can employ, for example, the STL (Structured Light) method or the ToF (Time of Flight) method as the distance measuring method. This makes it possible to measure the distance between the distance measuring device 5000 and the subject 4000 in sections based on the image signal, and also makes it possible to identify the three-dimensional shape of the subject 4000.

[0152] The above description of the rangefinder according to the tenth embodiment of this technology can be applied to other embodiments of this technology, unless there are any particular technical inconsistencies.

[0153] [11. Eleventh Embodiment of the Technology (Example of Electronic Device)] The technology can be applied to various products (electronic devices). The technology provides an electronic device comprising any of the light-emitting element, driving element, light-emitting device, and distance measuring device according to the first to eleventh embodiments.

[0154] The light-emitting device according to this technology can be applied, for example, to optical communication technology. This device can be used as a light source for high-speed transmission of optical signals in optical fiber communications and high-speed interconnects in data centers. In particular, it can be applied as a light source in the signal transmission section of optical communication systems using VCSELs or LEDs.

[0155] The light-emitting device according to this technology can be applied, for example, to sensor technology. This device can be applied to facial recognition systems in smartphones and tablet devices, and to distance measurement systems utilizing LiDAR technology. As a result, it functions as a light source in sensor systems that detect the distance and shape of objects with high precision.

[0156] The light-emitting device according to this technology can be applied, for example, to display technology. This light-emitting device can be applied to micro-LED displays and other next-generation display technologies. By using high-density light-emitting elements, high-resolution and low-power displays can be realized.

[0157] The light-emitting device related to this technology can be applied to medical devices. It can be used in medical devices that utilize optical signals, such as pulse oximeters and bio-optical monitoring devices. By achieving high-precision optical output, it contributes to improving diagnostic accuracy.

[0158] The light-emitting device related to this technology will be incorporated into augmented reality (AR) and virtual reality (VR) devices and used as a light source for spatial recognition and interface operation. This will enable high-speed and precise data acquisition, contributing to an improved user experience.

[0159] This technology may be implemented as a device mounted on any type of mobile vehicle, such as an automobile, electric vehicle, hybrid electric vehicle, motorcycle, bicycle, personal mobility device, airplane, drone, ship, or robot.

[0160] Figure 28 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile control system to which the technology described herein may be applied.

[0161] The vehicle control system 12000 comprises a plurality of electronic control units connected via a communication network 12001. In the example shown in Figure 28, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an external information detection unit 12030, an internal information detection unit 12040, and an integrated control unit 12050. The functional configuration of the integrated control unit 12050 is shown in the figure, which includes a microcomputer 12051, an audio / image output unit 12052, and an in-vehicle network interface 12053.

[0162] The drivetrain control unit 12010 controls the operation of devices related to the vehicle's drivetrain according to various programs. For example, the drivetrain control unit 12010 functions as a control device for a drivetrain generating device that generates driving force for the vehicle, such as an internal combustion engine or a drive motor; a drivetrain transmission mechanism that transmits driving force to the wheels; a steering mechanism that adjusts the steering angle of the vehicle; and a braking device that generates braking force for the vehicle.

[0163] The body system control unit 12020 controls the operation of various devices mounted on the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window system, or various lamps such as headlights, reverse lights, brake lights, turn signals, or fog lights. In this case, the body system control unit 12020 may receive radio waves transmitted from a portable device that replaces a key or signals from various switches. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock system, power window system, lamps, etc.

[0164] The external information detection unit 12030 detects information from outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the external information detection unit 12030. The external information detection unit 12030 causes the imaging unit 12031 to capture images of the outside of the vehicle and receives the captured images. Based on the received images, the external information detection unit 12030 may perform object detection processing such as detecting people, cars, obstacles, signs, or characters on the road surface, or distance detection processing.

[0165] The imaging unit 12031 is a light sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The imaging unit 12031 can output the electrical signal as an image or as distance measurement information. The light received by the imaging unit 12031 may be visible light or invisible light such as infrared light.

[0166] The in-vehicle information detection unit 12040 detects information inside the vehicle. The in-vehicle information detection unit 12040 is connected to, for example, a driver status detection unit 12041 that detects the driver's state. The driver status detection unit 12041 includes, for example, a camera that captures images of the driver, and the in-vehicle information detection unit 12040 may calculate the driver's level of fatigue or concentration, or determine whether the driver is drowsy, based on the detection information input from the driver status detection unit 12041.

[0167] The microcomputer 12051 can calculate control target values ​​for the drive force generator, steering mechanism, or braking device based on information inside and outside the vehicle acquired by the external information detection unit 12030 or the internal information detection unit 12040, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing ADAS (Advanced Driver Assistance System) functions, including collision avoidance or impact mitigation, following driving based on distance between vehicles, maintaining vehicle speed, vehicle collision warning, or vehicle lane departure warning.

[0168] Furthermore, the microcomputer 12051 can perform cooperative control for purposes such as autonomous driving, where the vehicle drives autonomously without driver intervention, by controlling the drive force generating device, steering mechanism, or braking device, etc., based on information about the vehicle's surroundings acquired by the external information detection unit 12030 or the internal information detection unit 12040.

[0169] Furthermore, the microcomputer 12051 can output control commands to the body system control unit 12020 based on external information acquired by the external information detection unit 12030. For example, the microcomputer 12051 can control the headlights according to the position of a preceding or oncoming vehicle detected by the external information detection unit 12030, and perform coordinated control aimed at reducing glare, such as switching from high beams to low beams.

[0170] The audio-image output unit 12052 transmits at least one of audio and image output signals to an output device capable of visually or audibly notifying information to the vehicle's occupants or to those outside the vehicle. In the example shown in Figure 28, the output devices include an audio speaker 12061, a display unit 12062, and an instrument panel 12063. The display unit 12062 may include, for example, at least one of an onboard display and a head-up display.

[0171] Figure 29 shows an example of the installation position of the imaging unit 12031.

[0172] In Figure 29, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0173] The imaging units 12101, 12102, 12103, 12104, and 12105 are installed, for example, on the front nose, side mirrors, rear bumper, back door, and the upper part of the windshield inside the vehicle 12100. The imaging unit 12101 installed on the front nose and the imaging unit 12105 installed on the upper part of the windshield inside the vehicle mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 installed on the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 installed on the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The imaging unit 12105 installed on the upper part of the windshield inside the vehicle is mainly used for detecting preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, or lanes.

[0174] Figure 29 shows an example of the imaging range of imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of imaging unit 12101 located on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of imaging units 12102 and 12103 located on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of imaging unit 12104 located on the rear bumper or back door. For example, by superimposing the image data captured by imaging units 12101 to 12104, an overhead view image of the vehicle 12100 can be obtained.

[0175] At least one of the imaging units 12101 to 12104 may have a function for acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera consisting of multiple image sensors, or an image sensor having pixels for phase difference detection.

[0176] For example, the microcomputer 12051, based on distance information obtained from the imaging units 12101 to 12104, can determine the distance to each object within the imaging range 12111 to 12114 and the temporal change of this distance (relative speed to the vehicle 12100). In particular, it can extract the closest object on the vehicle 12100's path that is traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (e.g., 0 km / h or more) as the preceding vehicle. Furthermore, the microcomputer 12051 can set a predetermined distance to be maintained before the preceding vehicle and perform automatic braking control (including follow-and-stop control) and automatic acceleration control (including follow-and-start control), etc. In this way, cooperative control aimed at autonomous driving, where the vehicle drives autonomously without driver intervention, can be performed.

[0177] For example, the microcomputer 12051 can use distance information obtained from imaging units 12101 to 12104 to classify and extract three-dimensional object data related to three-dimensional objects, such as motorcycles, passenger cars, large vehicles, pedestrians, utility poles, and other three-dimensional objects, and use this data for automatic obstacle avoidance. For example, the microcomputer 12051 identifies obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. The microcomputer 12051 then determines the collision risk, which indicates the degree of risk of collision with each obstacle. If the collision risk is above a set value and there is a possibility of collision, the microcomputer 12051 can provide driving assistance to avoid collisions by outputting a warning to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or evasive steering via the drive system control unit 12010.

[0178] At least one of the imaging units 12101 to 12104 may be an infrared camera that detects infrared light. For example, the microcomputer 12051 can recognize pedestrians by determining whether or not pedestrians are present in the images captured by the imaging units 12101 to 12104. Such pedestrian recognition is performed, for example, by a procedure to extract feature points from the images captured by the imaging units 12101 to 12104 as infrared cameras, and a procedure to perform pattern matching on a series of feature points that indicate the contour of an object to determine whether or not it is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the images captured by the imaging units 12101 to 12104 and recognizes a pedestrian, the audio-image output unit 12052 controls the display unit 12062 to superimpose a rectangular contour line for emphasis on the recognized pedestrian. The audio-image output unit 12052 may also control the display unit 12062 to display an icon indicating a pedestrian at a desired position.

[0179] The above describes an example of a vehicle control system to which this technology may be applied. This technology can be applied to, for example, the imaging unit 12031 in the configuration described above.

[0180] The specific numerical values, shapes, materials (including composition), etc., described herein are examples only and are not limited to these.

[0181] Furthermore, this technology can also take the following configurations: [1] A light-emitting element having a plurality of light-emitting mesa portions, with an insulating layer disposed between each of the mesa portions, and an internal space formed in a part of each of the insulating layers. [2] The light-emitting element according to [1], wherein an internal space is formed in all of the insulating layers. [3] The light-emitting element according to [1] or [2], wherein the thickness of the insulating layer located on the outer periphery of the light-emitting element is greater than the thickness of the insulating layer located on the inner periphery. [4] The light-emitting element according to any one of [1] to [3], wherein the thickness of the insulating layer covering the mesa portion is 1 μm or more. [5] The light-emitting element according to any one of [1] to [4], wherein the thickness of the insulating layer covering the region opposite to the end of the mesa portion is greater than the thickness of the insulating layer covering the end. [6] The light-emitting element according to any one of [1] to [5], wherein the height of the mesa portion is 2 μm or more. [7] The light-emitting element according to any one of [1] to [6], wherein the internal space is filled with an insulating material different from the material of the insulating layer. [8] The light-emitting element according to any one of [1] to [7], wherein a polymer material is used as the material for the insulating layer. [9] A driving element having a plurality of electrodes electrically connected to each of a plurality of mesa portions of the light-emitting element for driving the light-emitting element, with an insulating layer disposed between each of the electrodes, and an internal space formed in a part of each of the insulating layers.

[10] The driving element according to [9], wherein an internal space is formed in all of the insulating layers.

[11] A light-emitting device comprising a light-emitting element having a plurality of mesa portions, and a driving element having a plurality of electrodes electrically connected to each of the plurality of mesa portions for driving the light-emitting element, wherein an insulating layer is disposed between each of the mesa portions and the electrodes, and an internal space is formed in a part of each of the insulating layers.

[12] The light-emitting device according to

[11] , wherein the internal space is formed only in the insulating layer disposed on the light-emitting element.

[13] The light-emitting device according to

[11] , wherein the internal space is formed only in the insulating layer disposed on the driving element.

[14] The light-emitting device according to

[11] , wherein the internal space is formed in both the insulating layer disposed on the light-emitting element and the driving element, respectively.

[15] The light-emitting device according to any one of

[11] to

[14] , wherein the light-emitting element and the driving element are joined to each other by wafer-on-wafer (WoW) technology.

[16] The light-emitting device according to any one of

[11] to

[14] , wherein the light-emitting element and the driving element are joined to each other by chip-on-wafer (CoW) technology.

[17] The light-emitting device according to any one of

[11] to

[16] , which constitutes a vertical-cavity surface-emitting laser (VCSEL).

[18] The light-emitting device according to any one of

[11] to

[16] , which constitutes a light-emitting diode (LED).

[19] A distance measuring device comprising the light-emitting device according to any one of

[11] to

[18] .

[20] An electronic device comprising the distance measuring device according to

[19] .

[21] A method for manufacturing a light-emitting element, comprising: forming a plurality of light-emitting mesa portions; arranging an insulating layer between each of the mesa portions; and forming an internal space in a part of each of the insulating layers.

[22] A method for manufacturing a driving element, comprising: arranging a plurality of electrodes electrically connected to each of the plurality of mesa portions of the light-emitting element for driving the light-emitting element; arranging an insulating layer between each of the electrodes; and forming an internal space in a part of each of the insulating layers.

[23] A method for manufacturing a light-emitting device, comprising: forming a plurality of light-emitting mesa portions in the light-emitting element; arranging a first insulating layer between each of the mesa portions; forming a first internal space in a part of each of the first insulating layers; arranging a plurality of electrodes electrically connected to each of the plurality of mesa portions of the light-emitting element for driving the light-emitting element; arranging a second insulating layer between each of the electrodes; forming a second internal space in a part of each of the second insulating layers; and joining the light-emitting element and the driving element to each other.

[0182] 1 Light-emitting element 2 Driving element 4 Internal space 10 Substrate 11 Semiconductor layer 12 Semiconductor laminate 13 First conductivity layer 14 Active layer 15 Second conductivity layer 16 Insulating layer 17 Bonding surface 18 Insulating layer 19 Electrode 21 Insulating layer 22 Electrode 23 Seed layer 24 Switch 41 Mesa portion 42 Insulating film 43 Seed layer 44 Insulating material 1000 Light-emitting device 5000 Distance measuring device

Claims

1. A light-emitting element having multiple light-emitting mesa portions, with an insulating layer disposed between each of the mesa portions, and an internal space formed in a portion of each of the insulating layers.

2. The light-emitting element according to claim 1, wherein an internal space is formed in all of the insulating layers.

3. The light-emitting element according to claim 1, wherein the thickness of the insulating layer located on the outer periphery of the light-emitting element is greater than the thickness of the insulating layer located on the inner periphery of the light-emitting element.

4. The light-emitting element according to claim 1, wherein the thickness of the insulating layer covering the mesa portion is 1 μm or more.

5. The light-emitting element according to claim 1, wherein the thickness of the insulating layer covering the region opposite to the end of the mesa portion is greater than the thickness of the insulating layer covering the end.

6. The light-emitting element according to claim 1, wherein the height of the mesa portion is 2 μm or more.

7. The light-emitting element according to claim 1, wherein the internal space is filled with an insulating material different from the material of the insulating layer.

8. The light-emitting element according to claim 1, wherein a polymer material is used as the material for the insulating layer.

9. A driving element having multiple electrodes electrically connected to each of the multiple mesa portions of a light-emitting element, wherein an insulating layer is disposed between each of the electrodes, and an internal space is formed in a part of each of the insulating layers.

10. The drive element according to claim 9, wherein an internal space is formed in all of the insulating layers.

11. A light-emitting device comprising: a light-emitting element having a plurality of mesa portions; and a driving element electrically connected to each of the plurality of mesa portions and having a plurality of electrodes for driving the light-emitting element, wherein an insulating layer is disposed between each of the mesa portions and the electrodes, and an internal space is formed in a part of each of the insulating layers.

12. The light-emitting device according to claim 11, wherein the internal space is formed only in the insulating layer disposed on the light-emitting element.

13. The light-emitting device according to claim 11, wherein the internal space is formed only in the insulating layer disposed on the driving element.

14. The light-emitting device according to claim 11, wherein the internal space is formed in both the light-emitting element and the insulating layer disposed on the driving element, respectively.

15. The light-emitting device according to claim 11, wherein the light-emitting element and the driving element are bonded to each other by wafer-on-wafer (WoW) technology.

16. The light-emitting device according to claim 11, wherein the light-emitting element and the driving element are joined to each other by chip-on-wafer (CoW) technology.

17. The light-emitting device according to claim 11, comprising a vertical cavity surface-emitting laser (VCSEL).

18. The light-emitting device according to claim 11, comprising a light-emitting diode (LED).

19. A distance measuring device comprising the light-emitting device described in claim 11.

20. Electronic device comprising the distance measuring device described in claim 19.

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