Light-emitting device inspection method and manufacturing method

Abstract

To provide a method for inspecting a disconnection failure of a light emitting element.SOLUTION: An inspection method of a light emitting element, is an inspection method of a light emitting element 20, containing: a semiconductor structure 30 that contains an n-side semiconductor layer 31, a p-side semiconductor layer 32, and an active layer 33 that is arranged to between the n-side semiconductor layer 31 and the p-side semiconductor layer 32; and an electrode 40 that contains an n-side electrode 41 and a p-side electrode 42, and containing: a first imaging step of, in a state where the n-side electrode 41 and the p-side electrode 42 are electrically contacted to a conductive liquid 50, irradiating a light 60 to the light emitting element 20, and obtaining a first photoluminescence image; and a first inspection step of inspecting a disconnection failure of the light emitting element 20 on the basis of a light and dark of the first photoluminescence image to be obtained in the first imaging step.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a method for inspecting and manufacturing a light-emitting device. [Background technology]

[0002] As a method for inspecting semiconductors, a method for observing photoluminescence (PL) has been disclosed (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018-079657 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of an embodiment of the present disclosure is to provide a method for inspecting for open defects. [Means for solving the problem]

[0005] The method for inspecting a light-emitting element disclosed in the embodiment is a method for inspecting a light-emitting element including a semiconductor structure including an n-side semiconductor layer, a p-side semiconductor layer, and an active layer disposed between the n-side semiconductor layer and the p-side semiconductor layer, and an electrode including an n-side electrode and a p-side electrode, and includes a first imaging step of irradiating the light-emitting element with light while the n-side electrode and the p-side electrode are in electrical contact with a conductive liquid to obtain a first photoluminescence image, and a first inspection step of inspecting the light-emitting element for a disconnection defect based on the brightness of the first photoluminescence image obtained in the first imaging step.

[0006] Furthermore, the method for manufacturing a light-emitting element disclosed in the embodiment includes a preparation step of preparing a light-emitting element including a semiconductor structure including an n-side semiconductor layer, an active layer disposed on the n-side semiconductor layer, and a p-side semiconductor layer disposed on the active layer, and an electrode including an n-side electrode and a p-side electrode, and a selection step by the inspection method for light-emitting elements disclosed in the embodiment. [Effects of the Invention]

[0007] According to the embodiment of the present disclosure, inspection for disconnection defects can be performed. [Brief explanation of the drawings]

[0008] [Figure 1] 10 is a flowchart illustrating a method for inspecting a light-emitting element according to an embodiment. [Figure 2A] FIG. 2 is a plan view illustrating a growth substrate on which a light-emitting element is formed. [Figure 2B] FIG. 2B is an enlarged plan view illustrating a part of FIG. 2A. [Figure 2C] FIG. 2C is a cross-sectional view taken along line IIC-IIC in FIG. 2B. [Figure 3] 10 is a cross-sectional view illustrating a light-emitting element in a first inspection step. FIG. [Figure 4A] FIG. 2 is a plan view schematically showing a first PL image. [Figure 4B] FIG. 2 is a plan view schematically showing a visible light image. [Figure 4C] 1 is a photograph illustrating a first PL image. [Figure 5] FIG. 1 is a schematic diagram illustrating the configuration of an inspection apparatus according to an embodiment. [Figure 6] FIG. 2 is a plan view schematically showing a second PL image. [Figure 7] 1 is a flowchart illustrating a method for manufacturing a light-emitting element according to an embodiment. [Figure 8A] 1A to 1C are cross-sectional views illustrating a method for manufacturing a light-emitting element according to an embodiment. [Figure 8B] 1A to 1C are cross-sectional views illustrating a method for manufacturing a light-emitting element according to an embodiment. [Figure 8C]1A to 1C are cross-sectional views illustrating a method for manufacturing a light-emitting element according to an embodiment. [Figure 8D] 1A to 1C are cross-sectional views illustrating a method for manufacturing a light-emitting element according to an embodiment. [Figure 8E] 1A to 1C are plan views illustrating a method for manufacturing a light-emitting element according to an embodiment. [Figure 8F] 1A to 1C are cross-sectional views illustrating a method for manufacturing a light-emitting element according to an embodiment. [Figure 9] FIG. 2 is a perspective view illustrating a light emitting element. DETAILED DESCRIPTION OF THE INVENTION

[0009] An example of an embodiment will be described below with reference to the drawings. However, the embodiment described below exemplifies a light-emitting element inspection method and inspection device, as well as a light-emitting element and a manufacturing method thereof, for embodying the technical idea of ​​the present disclosure, and is not limited to the following. Furthermore, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described in the embodiment are merely examples and are not intended to limit the scope of the present invention. Note that the size and positional relationship of the components shown in each drawing may be exaggerated or simplified for clarity of explanation. Furthermore, in the embodiments, "cover" does not necessarily mean direct contact, but also includes indirect covering, for example, via another component.

[0010] [Light-emitting element inspection method] The method for inspecting a light emitting element according to the embodiment will be described with reference to the drawings.

[0011] 1, the light-emitting element inspection method S10 includes a first imaging step S11 and a first inspection step S12. The light-emitting element inspection method S10 further includes a second imaging step S21 and a second inspection step S22.

[0012] (light-emitting element) The light emitting element 20 to be subjected to the light emitting element inspection method S10 has at least a semiconductor structure 30 and an electrode 40.

[0013] 2C, the semiconductor structure 30 includes an n-side semiconductor layer 31, a p-side semiconductor layer 32, and an active layer 33 disposed between the n-side semiconductor layer 31 and the p-side semiconductor layer 32. The semiconductor structure 30 may include, for example, In X Al Y Ga 1-X-Y Nitride semiconductors such as N (0≦X, 0≦Y, X+Y≦1) can be used. Examples of nitride semiconductors include GaN, InGaN, AlGaN, and AlInGaN. The active layer 33 can have a quantum well structure including multiple well layers and multiple barrier layers. The emission peak wavelength of the semiconductor structure 30 is not particularly limited. The emission peak wavelength of the semiconductor structure 30 is, for example, 250 nm or more and 800 nm or less. As shown in FIG. 2A , the semiconductor structure 30 is disposed on a growth substrate B1, for example. The growth substrate B1 can be an insulating substrate such as sapphire or spinel (MgAl2O4). The light extraction surface of the light-emitting element 20 faces the growth substrate B1. The semiconductor structure 30 can have a conductive and transparent light-transmitting layer 34 on the p-side semiconductor layer 32.

[0014] 2A to 2C, the light-emitting element 20 has multiple element regions 35 spaced apart from one another; however, the light-emitting element 20 is required to have at least one element region 35. The element region 35 is a region that can function as a single light-emitting element. As shown in FIG. 2B, the multiple element regions 35 include at least a first element region 35A and a second element region 35B adjacent to the first element region 35A. As shown in FIG. 2C, the element region 35 includes an n-side semiconductor layer 31, an active layer 33, and a p-side semiconductor layer 32. The n-side semiconductor layer 31A of the first element region 35A and the n-side semiconductor layer 31B of the second element region 35B are continuous via a connection region 31E located between the n-side semiconductor layer 31A and the n-side semiconductor layer 31B. In FIG. 2C, the boundary between the first element region 35A and the connection region 31E and the boundary between the second element region 35B and the connection region 31E are indicated by two-dot chain lines.

[0015] The electrode 40 includes an n-side electrode 41 and a p-side electrode 42. The n-side electrode 41 has an n-side connection electrode 43 and an n-side conductive layer 45. As shown in FIG. 2C , the n-side semiconductor layer 31 is electrically connected to the n-side conductive layer 45 via the n-side connection electrode 43. The p-side electrode 42 has a p-side connection electrode 44 and a p-side conductive layer 46. The p-side semiconductor layer 32 is electrically connected to the p-side conductive layer 46 via the p-side connection electrode 44. The n-side electrode 41 and the p-side electrode 42 can be, for example, a single metal layer containing Ti, Rh, Au, Pt, Al, Ag, Rh, or Ru, or a stacked structure containing at least two of these metal layers.

[0016] The light-emitting element 20 further includes an insulating layer 210 that insulates the n-side connecting electrode 43 from the p-side connecting electrode 44. As shown in FIG. 2C , the insulating layer 210 covers part of the side surface of the n-side semiconductor layer 31, the side surface of the active layer 33, and the side surface of the p-side semiconductor layer 32. The insulating layer 210 also covers part of the upper surface and the side surface of the n-side connecting electrode 43, part of the upper surface and the side surface of the light-transmitting layer 34, and part of the upper surface and the side surface of the p-side connecting electrode 44. The insulating layer 210 is translucent to light from the active layer 33. The insulating layer 210 can be, for example, a silicon oxide film.

[0017] (First imaging step) As shown in Figure 3, the first imaging process S11 is a process in which light 60 is irradiated onto the light-emitting element 20 while the n-side electrode 41 and the p-side electrode 42 are in electrical contact with a conductive liquid 50, and a first photoluminescence image 71 (hereinafter abbreviated as "first PL image 71") is obtained.

[0018] The first imaging step S11 will be described. First, a light-emitting element 20 including a semiconductor structure 30 and an electrode 40 is prepared. Next, the electrode 40 of the prepared light-emitting element 20 is placed in contact with a conductive liquid 50. The electrode 40 being in contact with the liquid 50 allows the n-side electrode 41 and the p-side electrode 42 to be electrically short-circuited. Next, the prepared light-emitting element 20 is irradiated with light 60 to excite the light-emitting element 20. In the excited state, the light-emitting element 20 is imaged to obtain a first PL image 71. When irradiated with light 60, a photoluminescence emission 70 (hereinafter abbreviated as "PL emission 70") is generated in an element region 35 having a disconnection defect, while a PL emission 70 is not generated in an element region 35 having no disconnection defect. Here, a disconnection defect refers to a case where the electrode 40 is not electrically connected to the n-side semiconductor layer 31 and the p-side semiconductor layer 32 due to, for example, dust inclusion or poor deposition of the electrode 40 during the manufacturing process of the light-emitting element 20.

[0019] The conductive liquid 50 is, for example, an aqueous solution. The liquid 50 may have a conductivity of 1 μS / cm or more as long as all or part of the solute is ionized. The liquid 50 is preferably an aqueous solution of a weak acid or a weak alkali. For example, an aqueous solution of either citric acid or ammonia is more preferable. This can reduce corrosion of the electrode 40.

[0020] 3 , in the first imaging step S11, the light-emitting element 20 is imaged with at least the n-side electrode 41 and the p-side electrode 42 in contact with the liquid 50. The light-emitting element 20 may be imaged with the liquid 50 extending to between the p-side connecting electrode 44 and the p-side conductive layer 46, or the entire light-emitting element 20 may be imaged with the liquid 50.

[0021] The peak emission wavelength of the light 60 may be shorter than the absorption edge wavelength of the light-emitting element 20, which is the target, or may be shorter than the peak emission wavelength of the light-emitting element 20, which is the target. The peak emission wavelength of the light-emitting element 20 refers to the peak emission wavelength emitted by the semiconductor structure 30 included in the light-emitting element 20. For example, the peak emission wavelength of the light 60 is 400 nm or more and less than 470 nm. For example, if the peak emission wavelength of the light-emitting element 20 is 470 nm, the light 60 is irradiated with light shorter than 470 nm. For example, the peak emission wavelength of the light 60 may be set to 460 nm or less, which is approximately 10 nm shorter than the peak emission wavelength of the light-emitting element 20. This facilitates observation of the PL emission 70 in the first inspection step S12, which will be described later. The difference in peak emission wavelength between the light 60 and the PL emission 70 facilitates extraction of the wavelength required for observation using the second filter 132 and the dichroic mirror 133, which will be described later. The light 60 is irradiated from the n-side semiconductor layer 31 side. The light 60 is irradiated with a uniform intensity over the entire light emitting element 20. The irradiance of the light 60 is not particularly limited. For example, the irradiance of the light 60 is 0.5 W / cm. 2 More than 2W / cm 2 The irradiation time of the light 60 can be set appropriately depending on the irradiance of the light 60 and the imaging time of the inspection device 10, which will be described later. The irradiation time of the light 60 may be, for example, greater than 0 seconds. From the viewpoint of shortening the manufacturing process, the irradiation time may be 1 second or less.

[0022] FIG. 4A is a schematic diagram of a first PL image 71. The first PL image 71 includes, for example, 30 element regions 35. Regions where PL emission 70 is occurring are represented by white, and regions where PL emission 70 is not occurring are represented by dots. The 30 element regions 35 are labeled with row symbols R1-R5 and column symbols C1-C6 to identify their respective positions. Of the 30 element regions 35, two element regions 35 located at positions R2C3 and R4C5 are labeled by white, indicating that PL emission 70 is occurring. The other element regions 35 are labeled by dots, indicating that PL emission 70 is not occurring. FIG. 4C is a magnified photograph of a portion of the first PL image 71. In FIG. 4C, PL emission 70 is occurring in the central element region 35. In the first PL image 71, some light from the element region 35 where PL emission 70 is occurring may leak near the periphery of the element region 35 where PL emission 70 is occurring.

[0023] As shown in FIG. 1 , the first imaging step S11 may include, before or after the step of obtaining the first PL image, a step of obtaining a visible light image without short-circuiting the light-emitting element 20 and irradiating it with light 60. The visible light image is an image obtained by irradiating the light-emitting element 20 with visible light, such as white light, as illumination light for imaging. Note that this illumination light may include light 60 capable of exciting the light-emitting element 20, but primarily includes light of wavelengths that do not excite the light-emitting element 20. Therefore, the visible light image is different from the first PL image 71 and the second PL image 72 described below. It is preferable that the visible light image be captured so that the boundaries of the element regions 35 are clearly defined. This makes it easy to identify the positions of each element region. If the boundaries of the element regions 35 are clearly defined in the first PL image 71, the step of obtaining the visible light image may be omitted. Note that, because FIG. 4B is a visible light image, dots are added to indicate that PL emission 70 is not occurring.

[0024] The step of obtaining the first PL image is preferably carried out in a darkroom. The step of obtaining a visible light image can be carried out with lighting turned on in the darkroom in which the step of obtaining the first PL image was carried out, or can be carried out outside the darkroom.

[0025] (First inspection process) The first inspection step S12 is a step of inspecting the light emitting element 20 for disconnection defects based on the brightness of the first PL image 71 obtained in the first imaging step S11.

[0026] As shown in FIG. 1, the first inspection step S12 includes a step of identifying the position of the element region 35 where the PL emission 70 is occurring and a step of recording the identified position. The step of identifying the position is a step of identifying the element region 35 where the PL emission 70 is occurring, as shown in FIGS. 4A and 4C. In the first PL image 71, the element region 35 where the PL emission 70 is occurring is a region where a disconnection defect has occurred, and the element region 35 where the PL emission 70 is not occurring is a region where a disconnection defect has not occurred. The part where the PL emission 70 is occurring appears bright, and the part where the PL emission 70 is not occurring appears dark. Based on this brightness and darkness, the element region 35 where a disconnection defect has occurred is identified. The step of recording the identified position is a step of recording the position of the identified element region 35. In the example shown in FIG. 4A, the element regions 35 located at R2C3 and R4C5 are recorded as having a disconnection defect.

[0027] The first imaging step S11 and the first inspection step S12 enable inspection of multiple element regions 35 for disconnection defects to be performed simultaneously. This reduces the inspection time. For example, if the element regions 35 are small, inspecting each electrode 40 by applying a probe to it is time-consuming and the inspection time is likely to be long. Even if the element regions 35 are small, inspecting for disconnection defects can be easily performed by performing the first imaging step S11 and the first inspection step S12. Here, a small element region 35 means that the size of one side of the outer edge of the element region 35 is 100 μm or less, or that the size of one side is 60 μm or less.

[0028] (Inspection equipment) The first imaging step S11 and the first inspection step S12 can be performed using an inspection device 10. As shown in Fig. 5, the inspection device 10 includes a light source unit 12, a filter unit 13, and an imaging unit 14. Note that the inspection device 10 can also be used to perform a second imaging step S21 and a second inspection step S22, which will be described later.

[0029] The light source unit 12 has a light source capable of emitting light 60. The light source unit 12 has a light source that irradiates the light 60, which serves as excitation light for photoluminescence, onto the light emitting element 20. The light 60 passes through the filter unit 13 and is irradiated onto the light emitting element 20. The light source is, for example, an LED. The number of light sources may be one or more. For example, when the light source unit 12 has multiple light sources, a light source can be selected according to the emission peak wavelength of the light emitted from the light emitting element 20. Furthermore, when the light source unit 12 has one light source, for example, the filter unit 13 can block part of the light emitted by the light source and irradiate light of a selected wavelength.

[0030] The filter unit 13 is an optical filter that blocks light of a specific wavelength. The filter unit 13 includes a first filter 131 through which the light 60 passes, a second filter 132 through which the light emitted by the light-emitting element 20 passes, and a dichroic mirror 133. For example, the first filter 131 blocks light from the light source unit 12 that has a wavelength longer than the peak emission wavelength of the light-emitting element 20, which is the target. This allows light with a wavelength shorter than 470 nm to be irradiated onto the light-emitting element 20. If the light source unit 12 has a peak emission wavelength shorter than the peak emission wavelength of the target, the first filter may not be provided. The dichroic mirror 133 reflects light of a specific wavelength and transmits light with a wavelength longer than the specific wavelength. For example, the dichroic mirror 133 reflects light 60 with a peak emission wavelength of 460 nm, which is then irradiated onto the light-emitting element 20. For example, the dichroic mirror 133 transmits PL emission 70 having an emission peak wavelength of 470 nm, which then enters the second filter 132. The second filter 132 blocks light of wavelengths of the PL emission 70 that are not required for observation. This allows the imaging unit 14, which will be described later, to capture the PL emission 70 of the wavelength desired for observation. The first filter 131, the second filter 132, and the dichroic mirror 133 can be selected as appropriate depending on the wavelength of the excitation light or the PL light of the light-emitting element to be inspected.

[0031] The imaging unit 14 is a device capable of capturing an image of the PL emission 70. By capturing images using the imaging unit 14, a first PL image and a second PL image (described later) can be obtained. The imaging unit 14 is preferably a device that can also capture visible light images. The imaging unit 14 includes, for example, a camera. The camera is, for example, a visible light camera. When the emission peak wavelength of the light-emitting element 20, which is the target, is in the ultraviolet or infrared region, the camera is an ultraviolet camera or an infrared camera.

[0032] The inspection device 10 further includes an image processing unit 15. The image processing unit 15 is a device that processes data in conjunction with the imaging unit 14. Data of the first PL image 71 obtained in the first imaging step S11 is sent from the imaging unit 14 to the image processing unit 15. For example, the image processing unit 15 can perform a first process in which the outer edge of the light-emitting element 20 is determined from the first PL image 71 or the visible light image obtained by the imaging unit 14, and an address is assigned to the light-emitting element 20 to identify its position. The address is, for example, a row symbol and a column symbol as shown in FIG. 4A.

[0033] Furthermore, a second process can be performed in which the brightness at a predetermined wavelength is quantified for each light-emitting element 20 and the brightness value is compared with a predetermined threshold value. The image processing unit 15 can, for example, quantify the brightness of each element region 35 and determine that the element region 35 is emitting PL light if the quantized value is greater than a predetermined threshold value. The address assigned in the first process is compared with the determination result of the second process, and an element region 35 in which a disconnection defect has occurred is identified based on brightness and position information. The image processing unit 15 also records the position of the element region 35 determined to have a disconnection defect. The second process can be performed, for example, after the first imaging process S11 and the second imaging process S21, which will be described later, are performed.

[0034] The inspection device 10 further includes a water tank 101 and a stage 102 that supports the water tank 101. The inspection device 10 may also include a transfer arm 103 that transfers the light-emitting element 20. The light-emitting element 20 may also be transferred to the inspection device 10 by hand.

[0035] The water tank 101 is a component in which the light-emitting element 20 is placed. A conductive liquid 50 is placed in the water tank 101. The water tank 101 is provided with a holder 104 that holds the n-side electrode 41 and the p-side electrode 42 of the light-emitting element 20 horizontally within the water tank 101. The stage 102 can move the water tank 101 fixed by the holder 104 in the horizontal and vertical directions. The transport arm 103 transports the light-emitting element 20 by, for example, suctioning it.

[0036] As shown in FIG. 1, the light emitting device inspection method S10 can further include a second imaging step S21 and a second inspection step S22 before or after the first imaging step S11.

[0037] (Second imaging step) The second imaging step S21 is a step of irradiating the light emitting element 20 with light 60 without electrically contacting the n-side electrode 41 and the p-side electrode 42 with the conductive liquid 50 to obtain a second photoluminescence image 72 (hereinafter abbreviated as second PL image 72). For example, the n-side electrode 41 and the p-side electrode 42 are in the atmosphere and are not electrically short-circuited between them. In the second imaging step S21, an image of the light emitting element 20 is captured without using the liquid 50. The light 60 in the second imaging step S21 is irradiated using the same light source and under the same irradiation conditions as in the first imaging step S11.

[0038] In the second imaging step S21, light 60 is irradiated when the n-side electrode 41 and the p-side electrode 42 are not electrically short-circuited. This makes it possible to inspect the light emitting element 20 for short-circuit defects. No PL light 70 is emitted from the element region 35 where a short-circuit defect has occurred.

[0039] 6 schematically shows the second PL image 72. Of the 30 element regions 35, two element regions 35 at positions R1C5 and R4C2 are shown in white, indicating that PL light emission 70 is occurring. The other element regions 35 are shown as dots, indicating that PL light emission 70 is not occurring.

[0040] (Second inspection process) The second inspection step S22 is a step of inspecting the light emitting element 20 for short circuit defects based on the brightness of the second PL image 72 obtained in the second imaging step S21.

[0041] As shown in FIG. 1, the second inspection process S22 includes a step of identifying the position of the element region 35 where PL emission 70 is not occurring and a step of recording the identified position. The step of identifying the position is a step of identifying the element region 35 where PL emission 70 is not occurring, as shown in FIG. 6. In the second PL image 72, the element region 35 where PL emission 70 is not occurring is a region where a short circuit defect has occurred, and the element region 35 where PL emission 70 is occurring is a region where a short circuit defect has not occurred. The part where PL emission 70 is occurring appears bright, and the part where PL emission 70 is not occurring appears dark. Based on this brightness and darkness, the element region 35 where a short circuit defect has occurred is identified. The step of recording the identified position is a step of recording the position of the identified element region 35. In the example shown in FIG. 6, the element regions 35 located at R1C5 and R4C2 are recorded as short circuits.

[0042] The processing in the image processing unit 15 is basically the same as the processing in the first imaging step S11. Data of the second PL image 72 obtained in the second imaging step S21 is sent from the imaging unit 14 to the image processing unit 15. The image processing unit 15 can, for example, digitize the brightness of each element region 35 and determine that no PL light is being emitted if the value is smaller than a predetermined threshold. The address assigned in the first processing is compared with the determination result of the second processing, and a short circuit defect is identified from the brightness and position information. The image processing unit 15 also records the position of the element region 35 determined to be a short circuit defect.

[0043] The determination of a disconnection defect or a short-circuit defect in the first inspection step S12 and the second inspection step S22 may be made by a person visually inspecting the first PL image 71 or the second PL image 72, without relying on the image processing unit 15. In this case, the determination result may be input to the image processing unit 15 and recorded by the person.

[0044] [Method of manufacturing light-emitting element] Next, a method for manufacturing a light emitting device according to the embodiment will be described with reference to the drawings.

[0045] 7, the light-emitting device manufacturing method S30 includes a preparation step S31 of preparing a light-emitting device 20 including a semiconductor structure 30 including an n-side semiconductor layer 31, an active layer 33 disposed on the n-side semiconductor layer 31, and a p-side semiconductor layer 32 disposed on the active layer 33, and an electrode 40 including an n-side electrode 41 and a p-side electrode 42, and a selection step by a light-emitting device inspection method S10. The selection step includes at least a first selection step S32A. The selection step can further include a second selection step S32B. The light-emitting device manufacturing method S30 can also include a singulation step S33, a light extraction surface formation step S34, and a support substrate removal step S35.

[0046] (preparation process) The preparation step S31 is a step of preparing a light-emitting element 20 including a semiconductor structure 30 and an electrode 40. As shown in Fig. 8A, the light-emitting element 20 described in the light-emitting element inspection method S10 is prepared. In Fig. 8A, similar to Fig. 2C, the boundary between the first element region 35A and the connection region 31E and the boundary between the second element region 35B and the connection region 31E are indicated by two-dot chain lines.

[0047] (First sorting process) The first selection step S32A is a step of performing the first imaging step S11 on the prepared light-emitting elements 20.

[0048] (Singulation process) The singulation step S33 is a step of singulating adjacent element regions 35 into individual pieces.

[0049] First, as shown in FIG. 8B, after the first imaging step S11, the electrode 40 side of the light-emitting element 20 is bonded to the support substrate B2 via the adhesive layer 220 so that they face each other, and the growth substrate B1 is then removed. The adhesive layer 220 covers the n-side conductive layer 45, the p-side conductive layer 46, and the insulating layer 210. The adhesive layer 220 is, for example, an epoxy resin, an acrylic resin, or a polyimide resin. The growth substrate B1 can be removed by a method such as laser lift-off, grinding, polishing, or etching. When the growth substrate B1 is a sapphire substrate, it is preferably removed by laser lift-off.

[0050] Next, as shown in FIG. 8C , the surface 311 of the n-side semiconductor layer 31 exposed by removing the growth substrate B1 is polished by chemical mechanical polishing. Polishing is preferably performed so as to remove the connection region 31E. A part of the insulating layer 210 and the adhesive layer 220 may also be polished. As a result, adjacent element regions 35 become discontinuous, and the light-emitting elements 20 are separated into individual pieces. Hereinafter, the separated light-emitting elements 20 are referred to as light-emitting elements 21.

[0051] (Light extraction surface formation process) The light extraction surface forming step S34 is a step of roughening the surface 311 of the n-side semiconductor layer 31 to form a light extraction surface.

[0052] As shown in FIG. 8D, a first protective layer 231 is formed on the outer edge of the surface 311 of the n-side semiconductor layer 31. The first protective layer 231 is formed so as to cover the end of the insulating layer 210 as well. As shown in FIG. 8E, the first protective layer 231 is arranged in a frame shape on the surface 311 of the n-side semiconductor layer 31. The first protective layer 231 is, for example, a silicon oxide film. The first protective layer 231 is formed on the entire surface 311 by, for example, a sputtering method. The first protective layer 231 other than the outer periphery of the surface 311 is removed by reactive ion etching using a resist mask (not shown).

[0053] The surface 311 of the n-side semiconductor layer 31 is roughened. As shown in FIG. 8D , a rough surface is formed on the surface 311 of the n-side semiconductor layer 31 that is exposed from the first protective layer 231. Roughening the surface 311 of the n-side semiconductor layer 31, which serves as the light extraction surface, can improve the light extraction efficiency. For example, reactive ion etching or wet etching can be used to roughen the surface 311. The surface 311 can be roughened while leaving the resist mask used when removing the first protective layer 231 except for the outer periphery of the surface 311 on the first protective layer 231 at the outer periphery of the surface 311.

[0054] 8D, the second protective layer 232 is disposed so as to cover the roughened n-side semiconductor layer 31. The second protective layer 232 may or may not be disposed on the first protective layer 231. The second protective layer 232 is, for example, a silicon oxide film. The second protective layer 232 can be formed by, for example, a sputtering method.

[0055] After forming the second protective layer 232, parts of the adhesive layer 220 located between the individual light-emitting elements 21 are removed. As a result, as shown in Fig. 8D, the insulating layer 210 located on the side surfaces of the semiconductor structure 30 is exposed from parts of the adhesive layer 220. Furthermore, the multiple light-emitting elements 21 are separated from one another by spaces on the support substrate B2.

[0056] (Second sorting process) The second sorting step S32B is a step of distinguishing between non-defective products and defective products. The second sorting step S32B includes a step of performing a second imaging step S21 on the light-emitting element 21, and a step of performing a first inspection step S12 and a second inspection step S22.

[0057] The first inspection step S12 and the second inspection step S22 identify and record light-emitting elements 21 that are defective due to disconnection or short circuit. Based on the recorded inspection results, defective products are removed, for example, after the support substrate removal step S35 described below. Note that in FIG. 7, the second imaging step S21 is performed after the light extraction surface formation step S34, but it may also be performed before or after the first imaging step S11 in the first sorting step S32A, or it may be performed between the singulation step S33 and the light extraction surface formation step S34.

[0058] (Support substrate removal process) The support substrate removal step S35 is a step of removing the support substrate B2 and the adhesive layer 220. As shown in FIG. 8F , the support substrate B2 and the adhesive layer 220 are removed from the light-emitting element 21, exposing the n-side conductive layer 45 and the p-side conductive layer 46. The support substrate B2 is irradiated with laser light from the surface opposite to the surface facing the adhesive layer 220, thereby removing a portion of the adhesive layer 220 and removing the light-emitting element 21 from the support substrate B2. After the light-emitting element 21 is removed from the support substrate B2, the surface facing the second protective layer 232 is bonded to another adhesive support substrate. The adhesive layer 220 remaining on the light-emitting element 21 is then removed to expose the n-side conductive layer 45 and the p-side conductive layer 46. The light-emitting element 21 may be removed from the support substrate B2 after being bonded to another support substrate. The adhesive layer 220 remaining on the light-emitting element 21 can be removed by, for example, reactive ion etching.

[0059] Fig. 9 is a perspective view of the light-emitting element 21 from which the adhesive layer 220 has been removed, viewed from the side of the n-side conductive layer 45 and the p-side conductive layer 46. Note that Fig. 9 illustrates a schematic example in which some of the irregularities of the n-side conductive layer 45, the p-side conductive layer 46, and the insulating layer 210 shown in Fig. 8F are omitted.

[0060] The light-emitting element manufacturing method S30 can inspect for disconnection defects at each stage of the light-emitting element manufacturing process. This allows good light-emitting elements 21 to be incorporated into light-emitting devices. This improves yield.

[0061] The first inspection step S12 and the second inspection step S22 may be performed separately. The first inspection step S12 can be performed after the first imaging step S11. The second inspection step S22 can be performed after the second imaging step S21.

[0062] Embodiments of the present invention include the following inspection methods and manufacturing methods. [Section 1] A method for inspecting a light-emitting element including a semiconductor structure including an n-side semiconductor layer, a p-side semiconductor layer, and an active layer disposed between the n-side semiconductor layer and the p-side semiconductor layer, and electrodes including an n-side electrode and a p-side electrode, a first imaging step of irradiating the light emitting element with light in a state where the n-side electrode and the p-side electrode are in electrical contact with a conductive liquid, and obtaining a first photoluminescence image; a first inspection step of inspecting the light-emitting element for disconnection defects based on the brightness of the first photoluminescence image obtained in the first imaging step. [Section 2] a second imaging step of irradiating the light emitting element with the light without electrically contacting the n-side electrode and the p-side electrode with a conductive liquid, before or after the first imaging step, to obtain a second photoluminescence image; Item 2. The light-emitting element inspection method according to item 1, further comprising a second inspection step of inspecting the light-emitting element for short-circuit defects based on the brightness of the second photoluminescence image obtained in the second imaging step. [Section 3] Item 3. The method for inspecting a light-emitting element according to item 1 or 2, wherein the conductive liquid is an aqueous solution. [Section 4] Item 4. The method for inspecting a light-emitting element according to item 3, wherein the aqueous solution contains either citric acid or ammonia. [Section 5] 5. The method for inspecting a light emitting element according to any one of items 1 to 4, wherein the light irradiated onto the light emitting element has an emission peak wavelength of 400 nm or more and less than 470 nm. [Section 6] a preparation step of preparing a light-emitting device including a semiconductor structure including an n-side semiconductor layer, an active layer disposed on the n-side semiconductor layer, and a p-side semiconductor layer disposed on the active layer, and electrodes including an n-side electrode and a p-side electrode; Item 6. A method for manufacturing a light-emitting element, comprising: a selection step using the light-emitting element inspection method according to any one of items 1 to 5. [Section 7] In the preparing step, the semiconductor structure has a plurality of device regions spaced apart from one another, 7. The method for manufacturing a light-emitting device according to item 6, wherein each of the plurality of element regions includes the n-side semiconductor layer, the active layer, and the p-side semiconductor layer. [Section 8] In the preparation step, the plurality of element regions include at least a first element region and a second element region adjacent to the first element region; Item 8. The method for manufacturing a light-emitting element according to item 6 or 7, wherein the n-side semiconductor layer of the first element region and the n-side semiconductor layer of the second element region are continuous via a connection region. [Explanation of symbols]

[0063] 10 Inspection equipment 12 Light source section 13 Filter section 14 Imaging unit 15 Image processing section 20, 21 Light-emitting element 30 Semiconductor structure 31 n-side semiconductor layer 32 p-side semiconductor layer 33 Active layer 34 Translucent layer 35 Element Area 40 electrodes 41 n-side electrode 42 p side electrode 50 liquid 60 light 71 1st PL statue 72 2nd PL statue 101 Aquarium 102 Stages 103 Transfer arm 104 Holder 210 Insulating layer 220 Adhesive layer B1 growth substrate B2 Support board S10 Light-emitting element inspection method S11 First imaging process S12 First inspection process S21 Second imaging process S22 Second inspection process S30 Light-emitting device manufacturing method S31 Preparation process S32A First sorting process S32B Second sorting process S33 Singulation process S34 Light extraction surface formation process S35 Support substrate removal process

Claims

1. A method for inspecting a light-emitting element including a semiconductor structure including an n-side semiconductor layer, a p-side semiconductor layer, and an active layer disposed between the n-side semiconductor layer and the p-side semiconductor layer, and electrodes including an n-side electrode and a p-side electrode, the method comprising: a first imaging step of irradiating the light emitting element with light in a state where the n-side electrode and the p-side electrode are in electrical contact with the same conductive liquid, to obtain a first photoluminescence image; a first inspection step of inspecting the light-emitting element for a disconnection defect based on the brightness of the first photoluminescence image obtained in the first imaging step.

2. a second imaging step of irradiating the light emitting element with the light without electrically contacting the n-side electrode and the p-side electrode with a conductive liquid, before or after the first imaging step, to obtain a second photoluminescence image; The method for inspecting a light-emitting element according to claim 1 , further comprising a second inspection step of inspecting the light-emitting element for short-circuit defects based on the brightness of the second photoluminescence image obtained in the second imaging step.

3. 2. The method for inspecting a light-emitting element according to claim 1, wherein the conductive liquid is an aqueous solution.

4. 4. The method for inspecting a light-emitting element according to claim 3, wherein the aqueous solution contains either citric acid or ammonia.

5. 2. The method for inspecting a light emitting element according to claim 1, wherein the light irradiated onto the light emitting element has a peak emission wavelength of 400 nm or more and less than 470 nm.

6. a preparation step of preparing a light-emitting device including a semiconductor structure including an n-side semiconductor layer, an active layer disposed on the n-side semiconductor layer, and a p-side semiconductor layer disposed on the active layer, and electrodes including an n-side electrode and a p-side electrode; A method for manufacturing a light-emitting element, comprising: a selection step using the light-emitting element inspection method according to claim 1 .

7. In the preparing step, the semiconductor structure has a plurality of device regions spaced apart from one another, The method for manufacturing a light-emitting device according to claim 6 , wherein each of the plurality of element regions includes the n-side semiconductor layer, the active layer, and the p-side semiconductor layer.

8. In the preparation step, the plurality of element regions include at least a first element region and a second element region adjacent to the first element region; The method for manufacturing a light-emitting element according to claim 7 , wherein the n-side semiconductor layer of the first element region and the n-side semiconductor layer of the second element region are continuous with each other via a connection region.

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