Inspection device and inspection method

Abstract

An inspection device comprises: an image acquisition unit 11 for acquiring an entire image of a wafer including a plurality of blocks disposed at predetermined intervals, each of the plurality of blocks including a plurality of light-emitting elements; a block region setting unit 14 for setting a plurality of block regions, corresponding to the plurality of blocks, for the entire image; and an inspection unit 17 for inspecting at least one block region among the plurality of block regions and generating data indicating an inspection result.

Description

Inspection Device and Inspection Method

[0001] The present disclosure relates to an inspection device and an inspection method.

[0002] An inspection device for inspecting a wafer on which a plurality of light-emitting elements are formed is known (see, for example, Patent Document 1). In the inspection device described in Patent Document 1, excitation light is irradiated onto a wafer to be inspected, and fluorescence having a wavelength not included in the normal fluorescence spectrum among the fluorescence emitted by the light-emitting elements is imaged. Then, the inspection device determines the quality of the light-emitting elements based on the captured image.

[0003] International Publication No. 2021 / 195136

[0004] The wafer to be inspected can be utilized as a functional region such as a display by each of the plurality of light-emitting elements serving as pixels. The above-described inspection device assumes that the entire wafer is utilized as one functional region, and inspects each of the plurality of light-emitting elements with the entire wafer as the inspection target. On the other hand, there are cases where a specific region of the entire wafer is utilized as an independent functional region, and even in such cases, it is required to efficiently inspect the plurality of light-emitting elements.

[0005] The present disclosure provides an inspection device and an inspection method capable of efficiently inspecting a plurality of light-emitting elements constituting a functional region independently provided on a wafer.

[0006] The gist of the present disclosure is as follows. [1] An inspection device including an image acquisition unit that acquires an overall image of a wafer including a plurality of blocks arranged at a predetermined interval, each of the plurality of blocks including a plurality of light-emitting elements; a block region setting unit that sets a plurality of block regions corresponding to the plurality of blocks with respect to the overall image; and an inspection unit that inspects at least one of the plurality of block regions and generates data indicating an inspection result.

[0007] According to the inspection device described above, multiple block regions are defined from an overall image of a wafer containing multiple light-emitting elements, and at least one of these block regions is inspected. By dividing the multiple light-emitting elements contained in the wafer into multiple block regions in advance, multiple light-emitting elements in each block region, which can be independent functional regions of each other, can be efficiently inspected.

[0008] [2] The inspection apparatus according to [1], further comprising: a divided image setting unit that sets an image of a single light-emitting element as a reference image, divides the overall image into regions corresponding to the size of the reference image along a predetermined direction, and sets a plurality of divided images arranged continuously along the predetermined direction; and a similarity calculation unit that calculates the similarity between each of the plurality of divided images and the reference image, wherein the block region setting unit sets the plurality of block regions based on the similarity. In this case, the divided image setting unit can easily determine the size of the divided images based on the reference image, and by arranging the divided images continuously along a predetermined direction, a plurality of divided images can be set efficiently and without omission with respect to the overall image. Furthermore, based on the similarity calculated by the similarity calculation unit, the block region setting unit can set the block regions with high accuracy, thereby improving inspection accuracy.

[0009] [3] The inspection apparatus according to [2], wherein the block region setting unit determines that the divided images whose similarity exceeds the similarity threshold are similar images of the single light-emitting element, and sets the regions of the plurality of divided images that are determined to be similar images in a predetermined direction as a single block region, thereby setting a plurality of block regions on the overall image in which block regions of the same size as the single block region are arranged at regular intervals. In this case, since the block region setting unit determines similar images based on the similarity of each divided image, visual judgment by the user is not required, improving inspection efficiency and suppressing variability in judgment results. Furthermore, the block region setting unit can accurately set block regions as regions in which a plurality of light-emitting elements are densely packed together, based on regions that are determined to be similar images in a predetermined direction. If the series of processes from setting a plurality of divided images to setting a plurality of block regions is performed automatically, for example, a significant improvement in inspection efficiency can be achieved while maintaining high accuracy.

[0010] [4] The inspection apparatus according to [3], wherein the block region setting unit generates at least one piece of information from the size of each of the plurality of block regions, the reference position of the plurality of block regions, and the constant interval. In this case, the block region setting unit visually displays the information regarding the plurality of block regions, making it easier to perform processing such as comparing it with information regarding the plurality of block regions of another wafer.

[0011] [5] The inspection apparatus according to [3] or [4], wherein the segmented image setting unit sets the image of a single light-emitting element extracted from the overall image as the reference image, and arranges the segmented images along a column region set based on the width of the reference image and a row region set based on the height of the reference image. In this case, the segmented image setting unit can arrange the segmented images along the row region and the column region with high precision, and can set multiple segmented images more efficiently and without omissions with respect to the overall image.

[0012] [6] An inspection apparatus according to any one of [1] to [5], further comprising a selection receiving unit that receives the selection of at least one block region to be inspected from among the plurality of block regions set by the block region setting unit. In this case, by selecting the block region to be inspected, the inspection time is shortened and multiple light-emitting elements can be inspected more efficiently.

[0013] [7] An inspection method comprising: an image acquisition step of acquiring an overall image of a wafer which includes a plurality of blocks arranged at predetermined intervals, each of which includes a plurality of light-emitting elements; a block region setting step of setting a plurality of block regions corresponding to the plurality of blocks in the overall image; and an inspection step of inspecting at least one of the plurality of block regions and generating data indicating the inspection result.

[0014] According to the above inspection method, by setting multiple block regions corresponding to multiple blocks as the inspection target in the block region setting step, it is possible to inspect block regions rather than the entire image. Since each of the multiple blocks contains multiple light-emitting elements, each of the multiple blocks can be utilized as a single functional region. Furthermore, by inspecting at least one block region in the inspection step, multiple light-emitting elements can be efficiently inspected on a block region basis, i.e., on a functional region basis. Moreover, according to the above inspection method, multiple block regions can be accurately set even for wafers where the patterns of multiple blocks are unknown.

[0015] [8] The inspection method according to [7], further comprising: setting an image of a single light-emitting element as a reference image; dividing the overall image into regions corresponding to the size of the reference image along a predetermined direction to set a plurality of divided images arranged continuously along the predetermined direction; and calculating the similarity between each of the plurality of divided images and the reference image, wherein in the block region setting step, the plurality of block regions are set based on the similarity. In this case, the size of the divided images can be easily determined based on the reference image in the divided image setting step, and by arranging the divided images continuously along a predetermined direction, a plurality of divided images can be set efficiently and without omission with respect to the overall image. Furthermore, based on the similarity calculated in the similarity calculation step, the block regions can be set with high accuracy in the block region setting step, thereby improving inspection accuracy.

[0016] [9] The inspection method according to [8], wherein in the block region setting step, the divided images whose similarity exceeds the similarity threshold are determined to be similar images of the single light-emitting element, and the regions of the plurality of divided images that are determined to be similar images in a predetermined direction are set as a single block region, thereby setting a plurality of block regions on the overall image in which block regions of the same size as the single block region are arranged at regular intervals. In this case, by determining similar images based on the similarity of each divided image in the block region setting step, visual judgment by the user is not required, improving inspection efficiency and suppressing variability in judgment results. Furthermore, in the block region setting step, regions that are determined to be similar images in a predetermined direction are set as regions in which multiple light-emitting elements are densely clustered, thereby enabling accurate setting of block regions. If the series of processes from setting multiple divided images to setting multiple block regions is performed automatically, for example, a significant improvement in inspection efficiency can be achieved while maintaining high accuracy.

[0017]

[10] The inspection method according to [9], wherein the block region setting step generates at least one piece of information from the size of each of the plurality of block regions, the reference position of the plurality of block regions, and the constant interval. In this case, visually displaying the information about the plurality of block regions in the block region setting step makes it easier to perform processing such as comparing it with information about the plurality of block regions of another wafer.

[0018]

[11] The inspection method according to [9] or

[10] , wherein in the segmented image setting step, the image of a single light-emitting element extracted from the overall image is set as the reference image, and the segmented images are arranged along a column area set based on the width of the reference image and a row area set based on the height of the reference image. In this case, the segmented images can be arranged with high precision along the row area and the column area in the segmented image setting step, and multiple segmented images can be set more efficiently and without omissions with respect to the overall image.

[0019]

[12] An inspection method according to any one of [7] to

[11] , further comprising a selection acceptance step for accepting the selection of at least one block region to be inspected from among the plurality of block regions set in the block region setting step. In this case, by selecting the block region to be inspected, the inspection time is shortened and multiple light-emitting elements can be inspected more efficiently.

[0020] According to this disclosure, it is possible to provide an inspection apparatus and inspection method that can efficiently inspect multiple light-emitting elements in a functional domain.

[0021] This figure shows an example of a plan view of a wafer to be inspected. This is a configuration diagram of the inspection apparatus according to this embodiment. This is a configuration diagram of the control device shown in Figure 2. This figure shows an example of a fluorescence image acquired by the image acquisition unit. This figure shows an example of a state in which a region aligned with a predetermined direction is set relative to the overall image. This figure shows an example of multiple divided images. This figure shows an example of multiple similar images. This figure shows an example of multiple set block regions. This figure shows an example of multiple selected block regions. This is a flowchart showing an example of the overall flow of an inspection method using the inspection apparatus. This is a flowchart showing an example of the detailed flow of each step in Figure 10. This is a flowchart showing an example of a modified inspection method. This figure shows an example of an overall image including the region to be inspected.

[0022] Hereinafter, preferred embodiments of an inspection apparatus according to one embodiment of this disclosure will be described in detail with reference to the drawings.

[0023] [Configuration of the wafer to be inspected] The inspection apparatus according to this embodiment is an apparatus for inspecting wafers. Figure 1 is a diagram showing an example of a plan view of a wafer to be inspected. The wafer W includes a plurality of blocks B1 arranged at predetermined intervals. Each of the plurality of blocks B1 includes a plurality of light-emitting elements. The plurality of blocks B1 are regions on the wafer W in which the plurality of light-emitting elements are formed. The plurality of light-emitting elements are not formed in regions on the wafer W other than the plurality of blocks B1. Examples of light-emitting elements include LEDs, mini-LEDs, micro-LEDs, SLD elements, laser elements, vertical laser elements (VCSELs), etc.

[0024] Each of the multiple blocks B1 can be used as a functional area, such as a display. The wafer W is then, for example, inspected by an inspection device and then diced into multiple chips that match the size of each block B1. Each chip cut from the wafer W may be used as a display device.

[0025] Each of the multiple blocks B1 has an arbitrary shape. Each of the multiple blocks B1 may be rectangular, for example, and in the example in Figure 1, it is square. Each of the multiple blocks B1 is the same size as the others, but is not limited to this. Each of the multiple blocks B1 may be different sizes from the others. The multiple blocks B1 are arranged at a constant interval T1 in the X and Y directions. The length of the interval T1 between adjacent blocks B1 in the X and Y directions may be shorter or longer than the width of each block B1. Note that when the thickness direction of the wafer W is the Z direction, the X direction is a direction perpendicular to the Z direction, and the Y direction is a direction perpendicular to both the Z and X directions.

[0026] Multiple blocks B1 include one or more blocks B1. Each block B1 may be formed at any position on the wafer W. In the example of Figure 1, the multiple blocks B1 are arranged in a matrix. A 2x2 block B1 is placed in the center of the wafer W, and a pair of 1x2 blocks B1 and a pair of 2x1 blocks B1 are placed on either side of this 2x2 block B1. In the example of Figure 1, the multiple blocks B1 are densely packed on the wafer W and formed to be point-symmetric with respect to the center of the wafer W. The multiple blocks B1 may be formed on the wafer W without symmetry.

[0027] [Configuration of the Inspection Apparatus] Figure 2 is a configuration diagram of the inspection apparatus according to this embodiment. The inspection apparatus 1 acquires a pattern image or a photoluminescence image of a plurality of light-emitting elements formed on a wafer W, and performs a quality determination of each light-emitting element for each block B1 based on the acquired image. A pattern image is an image generated by irradiating the wafer W with light and detecting the light reflected from the surface of the wafer W, and is used, for example, to inspect the appearance of a plurality of light-emitting elements. A photoluminescence image is an image generated by irradiating the wafer W with excitation light and detecting the light emitted by a plurality of light-emitting elements, and is used, for example, to inspect defects inside a plurality of light-emitting elements. The inspection apparatus 1 in the present invention will be described mainly as an apparatus for acquiring photoluminescence images.

[0028] The inspection device 1 comprises a chuck 101, an XY stage 102, an excitation light source 20, an optical system 30, a dichroic mirror 40, an objective lens 51, a Z stage 52, an imaging lens 71, a camera 81, a dark box 90, and a control device 10. The dark box 90 houses the components of the above configuration except for the control device 10, and is provided to prevent external light from affecting each of the components housed in it. In addition, each component housed in the dark box 90 may be mounted on a vibration isolation table in order to improve the quality of the image captured by the camera 81 (improvement of image quality and prevention of image misalignment).

[0029] The chuck 101 is a holding member that holds the wafer W. The chuck 101 holds the wafer W, for example, by vacuum adsorption. The XY stage 102 is a stage that moves the chuck 101 holding the wafer W in the XY direction. The XY stage 102 moves the chuck 101 in the XY direction in accordance with the control of the control device 10 so that each of the multiple light-emitting elements is sequentially designated as an irradiation area for excitation light.

[0030] The excitation light source 20 is a light source that generates excitation light to be irradiated onto the wafer W and irradiates the wafer W with said excitation light. The excitation light source 20 can be any light source capable of generating light that includes a wavelength that excites the light-emitting elements of the wafer W, such as an LED, laser, halogen lamp, mercury lamp, D2 lamp, plasma light source, etc.

[0031] The optical system 30 comprises an optical fiber cable 31 and a light guide lens 32. The optical fiber cable 31 is an optical fiber cable for guiding light connected to the excitation light source 20. The light guide lens 32 is, for example, a single or composite convex lens, which guides the excitation light that has arrived via the optical fiber cable 31 toward the dichroic mirror 40.

[0032] The dichroic mirror 40 is a mirror made using a special optical material, and is configured to reflect excitation light towards the objective lens 51 and transmit photoluminescence (fluorescence) from the light-emitting element, which is light in a different wavelength band than the excitation light, towards the imaging lens 71.

[0033] The objective lens 51 is configured for observing the wafer W and focuses the excitation light guided by the dichroic mirror 40 onto the wafer W. The Z-stage 52 adjusts the focus by moving the objective lens 51 in the Z direction, that is, in a direction intersecting the mounting surface of the wafer W on the chuck 101.

[0034] The imaging lens 71 is a lens that images the fluorescence transmitted through the dichroic mirror 40 and guides the fluorescence to the camera 81. The camera 81 is an imaging unit that images the fluorescence from the wafer W. The camera 81 outputs the fluorescence image, which is the imaging result, to the control device 10. The camera 81 is, for example, an area image sensor such as a CCD or MOS.

[0035] The control device 10 controls the XY stage 102, the excitation light source 20, the Z stage 52, and the camera 81. Specifically, the control device 10 adjusts the irradiation area of ​​the excitation light (the irradiation area on the wafer W) by controlling the XY stage 102. The control device 10 sequentially scans the irradiation area of ​​the excitation light by controlling the XY stage 102. As a result, the camera 81 sequentially outputs fluorescence images for each irradiation area of ​​the excitation light to the control device 10. The control device 10 adjusts the focus related to the excitation light by controlling the Z stage 52. The control device 10 adjusts the emission of the excitation light and adjusts the wavelength and amplitude of the excitation light by controlling the excitation light source 20. The control device 10 adjusts the acquisition of fluorescence images by controlling the camera 81. In addition, the control device 10 sets multiple block regions corresponding to multiple blocks B1 and determines the quality of the light-emitting elements on the wafer W based on the fluorescence images captured by the camera 81 (details will be described later).

[0036] The control device 10 is a computer, and physically it is composed of memory such as RAM and ROM, a processor (arithmetic circuit) such as a CPU, a communication interface, and a storage unit such as a hard disk. The control device 10 can be, for example, a personal computer, a cloud server, or a smart device (smartphone, tablet terminal, etc.). The control device 10 functions by executing a program stored in memory using the CPU of the computer system.

[0037] As shown in Figure 3, the control device 10 includes an image acquisition unit 11, a segmented image setting unit 12, a similarity calculation unit 13, a block area setting unit 14, a display unit 15, a selection reception unit 16, an inspection unit 17, and an input device 18.

[0038] The image acquisition unit 11 acquires the fluorescence image captured by the camera 81. Figure 4 shows an example of a fluorescence image acquired by the image acquisition unit. The image acquisition unit 11, for example, synthesizes fluorescence images for each irradiation area of ​​the excitation light input from the camera 81 to acquire an overall image G1 of the wafer W, as shown in Figure 4(a). The image acquisition unit 11 outputs the acquired overall image G1 to the segmented image setting unit 12.

[0039] The overall image G1 contains a fluorescence image of the entire wafer W. As shown in Figure 4(b), when the overall image G1 is magnified, multiple light-emitting elements S1 are arranged in two dimensions on the wafer W. The multiple light-emitting elements S1 are arranged with a constant height HT along the X direction and a constant width WD along the Y direction. Specifically, the multiple light-emitting elements S1 are formed on multiple blocks B1, but at the time the overall image G1 is acquired, the control device 10 has not yet identified the positions of the multiple blocks B1. The control device 10 identifies the positions of the multiple blocks B1 by performing various processes described later based on the overall image G1, and sets multiple block regions corresponding to the multiple blocks B1 on the overall image G1. The size of each of the multiple light-emitting elements S1 is the same. Height HT is the height of a single light-emitting element S1 and is the length of a single light-emitting element S1 in a predetermined direction (e.g., the Y direction). Width WD is the width of a single light-emitting element S1 and is the length of a single light-emitting element S1 in a direction perpendicular to the predetermined direction (e.g., the X direction).

[0040] Patterns other than the multiple light-emitting elements S1 may be formed on the wafer W. As shown in Figure 4(b), for example, an alignment pattern AP is formed on the wafer W. Instead of the multiple light-emitting elements S1, the alignment pattern AP includes arbitrary shapes that serve as markers during alignment. In the example in Figure 4(b), the alignment pattern AP includes a rectangular region and a shape with rounded corners at the center of the region. The alignment pattern AP is, for example, a pattern used as a starting point when adjusting the irradiation area of ​​the excitation light. The alignment pattern AP is formed on the wafer W in regions other than the multiple blocks B1.

[0041] The segmented image setting unit 12 sets the image of a single light-emitting element S1 as the reference image G2, as shown in Figure 4(c). The segmented image setting unit 12 extracts the image of a single light-emitting element S1 from the overall image G1 input from the image acquisition unit 11, for example, and sets the extracted image as the reference image G2. The segmented image setting unit 12 may also accept the image of a single light-emitting element S1 selected by the user and set the accepted image as the reference image G2. Alternatively, the segmented image setting unit 12 may store the reference image G2 in advance without extracting the image of a single light-emitting element S1 from the overall image G1. The segmented image setting unit 12 outputs the reference image G2 to the similarity calculation unit 13.

[0042] A single light-emitting element S1 includes an internal pattern S11. In the example of Figure 4(c), the single light-emitting element S1 includes two holes aligned in the Y direction as the internal pattern S11. These holes are, for example, vias for connecting the electrodes of a micro-LED to an external circuit when the light-emitting element S1 is a micro-LED. The internal pattern S11 may also become a feature portion within the reference image G2 when the similarity calculation unit, described later, calculates the similarity based on the reference image G2.

[0043] The divided image setting unit 12 divides the entire image G1 along a predetermined direction into regions corresponding to the size of the reference image G2, and sets a plurality of divided images arranged continuously along the predetermined direction. When setting the plurality of divided images, the divided image setting unit 12 first sets a region along the predetermined direction on the entire image G1. FIG. 5 is a diagram showing an example of a state in which a region along the predetermined direction is set for the entire image. The region along the predetermined direction includes a row region RH that is a region along the X direction and a column region RV that is a region along the Y direction.

[0044] The divided image setting unit 12 sets the column region RV based on the width WD of the reference image G2. The width WD is the width of the reference image G2 and corresponds to the width of a single light-emitting element S1. Therefore, in each column region RV, images of a plurality of light-emitting elements S1 are arranged along the Y direction. Also, the divided image setting unit 12 sets the row region RH based on the height HT of the reference image G2. The height HT is the height of the reference image G2 and corresponds to the height of a single light-emitting element S1. Therefore, in each row region RH, images of a plurality of light-emitting elements S1 are arranged along the X direction. The divided image setting unit 12 sets the row region RH and the column region RV over the entire image G1. For this reason, on the entire image G1, a plurality of column regions RV are arranged side by side along the X direction, and a plurality of row regions RH are arranged side by side along the Y direction. The divided image setting unit 12 also sets the row region RH and the column region RV on the image of the alignment pattern AP.

[0045] Figure 6 shows an example of multiple divided images. The divided image setting unit 12 divides the overall image G1 into single divided images G3, where each of the multiple column regions RV and each of the multiple row regions RH intersect. Each single divided image G3 is a region corresponding to the size of the reference image G2. Therefore, the width of a single divided image G3 is width WD, and its height is height HT. In this way, the divided image setting unit 12 divides the overall image G1 along the X and Y directions and sets up multiple divided images G3 arranged continuously along the X and Y directions. The divided image setting unit 12 also sets up multiple divided images G3 on the alignment pattern AP image. The divided image setting unit 12 outputs the multiple divided images G3 to the similarity calculation unit 13.

[0046] The similarity calculation unit 13 calculates the similarity between each of the multiple divided images G3 and the reference image G2. For example, the similarity calculation unit 13 calculates the similarity for each of the multiple divided images G3 sequentially while sliding the reference image G2 in the X and Y directions within the multiple divided images G3. In calculating the similarity, the similarity calculation unit 13 may obtain the pixel value of each pixel in the reference image G2 and the pixel value of each pixel in each divided image G3. The similarity calculation unit 13 may then calculate the similarity using normalized cross-correlation. In this case, the similarity calculation unit 13 may calculate the similarity as the normalized value obtained by summing the correlations between the pixel values ​​of each pixel in the reference image G2 and the pixel values ​​of each pixel in each divided image G3. In this case, the larger the sum of the correlations, the higher the similarity.

[0047] The similarity calculation unit 13 may calculate the similarity using the least squares sum. In this case, the similarity calculation unit 13 may calculate the similarity as the sum of the squares of the differences between the pixel value of each pixel in the reference image G2 and the pixel value of each pixel in each divided image G3. In this calculation method, the smaller the sum of the squares of the differences, the higher the similarity. The similarity calculation unit 13 may also extract feature parts from the reference image G2 and each divided image G3 and compare the feature quantities of the feature parts of each image. The feature parts are, for example, the parts of the internal pattern S11 in each image. In this case, the closer the feature quantities of each image are, the higher the similarity.

[0048] The similarity calculation unit 13 may calculate the similarity at a predetermined gradation. For example, when the similarity calculation unit 13 calculates the similarity at 4096 gradations, the maximum value is '4096' in decimal notation, and the minimum value is '0' in decimal notation. The maximum value is the value when each divided image G3 completely matches the reference image G2. The minimum value is the value when there is no pattern to be compared in each divided image G3. The similarity calculation unit 13 outputs the similarity calculated for each divided image G3 to the block area setting unit 14.

[0049] The block area setting unit 14 sets a plurality of block areas corresponding to a plurality of blocks B1 based on the similarity input from the similarity calculation unit 13. When setting the plurality of block areas, the block area setting unit 14 determines a similar image G4 among the plurality of divided images G3. FIG. 7 is a diagram showing an example of a plurality of similar images. The block area setting unit 14 determines a divided image G3 whose similarity exceeds the similarity threshold among the plurality of divided images G3 as a similar image G4 of a single light emitting element S1. The block area setting unit 14 determines a divided image G3 whose similarity is below the similarity threshold among the plurality of divided images G3 as a non-similar image G5 of a single light emitting element S1.

[0050] The similarity threshold is a predetermined value between the minimum value and the maximum value of the similarity. For example, when the similarity calculation unit 13 calculates the similarity at 4096 gradations, the similarity threshold is any value between '0', which is the minimum value in decimal notation, and '4096', which is the maximum value. Among the plurality of divided images G3, the image of a single light emitting element S1 has a similarity close to the maximum value, so it exceeds the similarity threshold and is determined as a similar image G4. On the other hand, among the plurality of divided images G3, the image in which a single light emitting element S1 does not exist has a similarity close to the minimum value, so it is below the similarity threshold and is determined as a non-similar image G5. As shown in FIG. 7, since there is no single light emitting element S1 in the divided image G3 on the alignment pattern AP, these images are determined as non-similar images G5.

[0051] The block region setting unit 14 sets a single block region from among the multiple divided images G3 that are determined to be similar images G4 in a predetermined direction. As a result, the block region setting unit 14 sets multiple block regions on the overall image G1 in which block regions of the same size as a single block region B2 are arranged at regular intervals. Here, the predetermined direction is the X direction and the Y direction. Figure 8 is a diagram showing an example of the set multiple block regions. In the example of Figure 8, the block region setting unit 14 displays a block region image G6 on the overall image G1 on the display unit 15, in which multiple block regions B2 are arranged. The display unit 15 is a monitor or display. The multiple block regions B2 on the block region image G6 correspond to the multiple blocks B1 shown in Figure 1. The multiple blocks B1 are regions in which multiple light-emitting elements S1 are formed along the X direction and the Y direction. Therefore, the multiple divided images G3 located within the image of the multiple blocks B1 are determined to be similar images G4 in a predetermined direction and the Y direction, and are set as multiple block regions B2. Multiple block regions B2 are arranged at regular intervals T1 in the X and Y directions to correspond to multiple blocks B1.

[0052] In contrast, multiple light-emitting elements S1 are not formed in areas other than the multiple blocks B1. Therefore, the multiple segmented images G3 located outside the image of the multiple blocks B1 are judged to be dissimilar images G5 in the X and Y directions and are not set as multiple block regions B2. For example, among the multiple blocks B1, the interval T1 between adjacent blocks B1 in the X and Y directions is not set as a block region B2. The segmented images on the alignment pattern AP described above are located, for example, within such an interval T1.

[0053] As shown in Figure 8, the block region setting unit 14 may set multiple sub-block regions B3 in the block region image G6. The sub-block regions B3 are multiple divided images G3 located outside the image of the multiple blocks B1, and are regions determined to be dissimilar images G5. After setting multiple block regions B2, the block region setting unit 14 may place sub-block regions B3 of the same size as a single block region B2 at intervals T1 in the empty space on the block region image G6. In the example in Figure 8, multiple sub-block regions B3 are set at the four corners of the block region image G6. When the block region image G6 is displayed on the display unit 15, the block region setting unit 14 may, for example, display the multiple block regions B2 and the multiple sub-block regions B3 in different colors on the display unit 15 so that the user can distinguish between them.

[0054] The block area setting unit 14 generates at least one piece of information from the following: the size of each of the multiple block areas B2, the reference position of the multiple block areas B2, and a fixed interval T1. In the example in Figure 8, the block area setting unit 14 displays the block width and block height as the size of each block area B2 on the display unit 15. If each block is a square, the block width will be the same value as the block height. The block area setting unit 14 displays the X position, which indicates the position in the X direction, and the Y position, which indicates the position in the Y direction, on the display unit 15 as the reference position. The reference position is, for example, the position coordinates of the reference block area B2 among the multiple block areas B2. The reference block area B2 may be predetermined or selected by the user. The position coordinates may be the center coordinates of each block area B2, or the coordinates of the corners of each block area B2. The block area setting unit 14 may also display the position coordinates of multiple sub-block areas B3. The block area setting unit 14 displays the interval T1 on the display unit 15, which is the interval in the X direction (X interval) and the interval in the Y direction (Y interval). The X interval is the same value as the Y interval.

[0055] The block area setting unit 14 may receive input from the user and adjust the parameters of each of the multiple block areas B2, such as size, reference position, and spacing T1. The user inputs the adjustment values, for example, from an input device 18. The input device 18 is, for example, a touch panel, mouse, or keyboard. The adjustment results are displayed on the display unit 15. For example, the user may directly change the numerical values ​​of each parameter, or they may adjust them using a cursor (not shown) displayed on the display unit 15. The block area setting unit 14 may also receive input from the user and change the display format of the block area image G6 displayed on the display unit 15. The display format is, for example, the color and border thickness of the multiple block areas B2. The block area setting unit 14 outputs the set multiple block areas B2 to the selection receiving unit 16.

[0056] The selection reception unit 16 receives the selection of at least one block region B2 to be inspected from among a plurality of block regions B2 set by the block region setting unit 14. The selection reception unit 16 receives the selection of the block region B2 to be inspected from the user, for example. The user inputs the block region B2 to be inspected from the input device 18, for example. The selected block region B2 is displayed on the display unit 15. Figure 9 is a diagram showing an example of a plurality of selected block regions. As shown in Figure 9, the selection reception unit 16 may, for example, display the selected block region B21 and the unselected block region B22 on the display unit 15 in different colors so that the user can distinguish between them. The selection reception unit 16 outputs the selected at least one block region B21 to the inspection unit 17.

[0057] The inspection unit 17 inspects at least one selected block region B21 and generates data indicating the inspection result. The inspection unit 17 derives the average brightness of the image of each light-emitting element S1 within the block region B21 and associates the address and average brightness for the image of each light-emitting element S1. For each address (each light-emitting element), the inspection unit 17 derives an evaluation index from the absolute brightness and relative brightness. Relative brightness is the brightness ratio of the light-emitting element S1 to be derived to the average brightness of the image of the group of light-emitting elements, including the light-emitting element S1 to be derived and the surrounding light-emitting elements S1. For example, the inspection unit 17 derives the evaluation index from the product of absolute brightness and relative brightness. Once the inspection unit 17 has derived the evaluation index for all light-emitting elements, it rearranges the light-emitting elements S1 in descending order of their evaluation index. The evaluation index decreases sharply beyond a certain point (change point). The inspection unit 17 may, for example, use such change points as thresholds to determine that light-emitting elements S1 whose evaluation index is equal to or greater than the threshold are good products (good pixels), and light-emitting elements S1 whose evaluation index is less than the threshold are defective products (defective pixels). The inspection unit 17 then generates a list of addresses and judgment results for each image of the light-emitting elements S1 as data indicating the inspection results. The inspection unit 17 outputs the data indicating the inspection results. The inspection unit 17 may display the data indicating the inspection results on the display unit 15 for each block area B21, or transmit it to an external device. Alternatively, the inspection unit 17 may store the data indicating the inspection results internally.

[0058] [Inspection Method] Figure 10 is a flowchart showing an example of the overall flow of the inspection method using the inspection device described above. Figure 11 is a flowchart showing an example of the detailed flow of each step in Figure 10. The inspection method includes steps ST11 to ST13, as shown in Figure 10. Steps ST11 to ST13 are performed in order.

[0059] In step ST11, an overall image G1 of the wafer W is acquired, which includes a plurality of blocks B1 arranged at a predetermined interval T1, and each of the plurality of blocks B1 includes a plurality of light-emitting elements S1 (image acquisition step). Step ST11 includes steps ST21 and ST22 shown in Figure 11. In step ST21, the excitation light source 20 generates excitation light to be irradiated onto the wafer W and irradiates the wafer W with the excitation light. At this time, the XY stage 102 moves the chuck 101 in the XY direction according to the control of the control device 10 so that each of the plurality of light-emitting elements S1 is sequentially designated as an irradiation area of ​​the excitation light. In step ST22, the image acquisition unit 11 synthesizes fluorescence images for each irradiation area of ​​the excitation light input from, for example, the camera 81, and acquires an overall image G1 of the wafer W as shown in Figure 4(a).

[0060] In step ST12, multiple block regions B2 corresponding to multiple blocks B1 are set for the overall image G1 (block region setting step). Step ST12 includes steps ST23 to ST29 shown in Figure 11. In step ST23, the divided image setting unit 12 sets an image of a single light-emitting element S1 as a reference image G2, as shown in Figure 4(c). The divided image setting unit 12 sets an image of a single light-emitting element S1 extracted from the overall image G1 as the reference image G2, for example. Subsequently, in step ST24, the divided image setting unit 12 sets a column region RV based on the width WD of the reference image G2 and sets a row region RH based on the height HT of the reference image G2, as shown in Figure 5. Then, in step ST25, the divided image setting unit 12 divides the overall image G1 into regions corresponding to the size of the reference image G2 along the X and Y directions, as shown in Figure 6, and arranges multiple divided images G3 continuously along the X and Y directions. Specifically, the segmented image setting unit 12 divides the overall image G1 into segments, with each of the multiple column regions RV and each of the multiple row regions RH intersecting as a single segmented image G3, and arranges multiple segmented images G3 along the multiple column regions RV and the multiple row regions RH. The steps ST23 to ST25 described above correspond to the segmented image setting step.

[0061] Next, in step ST26, the similarity calculation unit 13 calculates the similarity between each of the multiple divided images G3 and the reference image G2 (similarity calculation step). The similarity calculation unit 13 may calculate the similarity by normalized cross-correlation. Next, in step ST27, the block region setting unit 14 determines similar images G4 from among the multiple divided images G3 when setting multiple block regions as shown in Figure 7. The block region setting unit 14 determines that the divided images G3 whose similarity exceeds the similarity threshold are similar images G4 of a single light-emitting element S1.

[0062] Next, in step ST28, the block region setting unit 14 sets up multiple block regions B2 corresponding to multiple blocks B1, as shown in Figure 8, based on the similarity input from the similarity calculation unit 13. Specifically, the block region setting unit 14 sets up a single block region B2 in the region of the multiple divided images G3 that is determined to be a similar image G4 in the X and Y directions consecutively. As a result, the block region setting unit 14 sets up multiple block regions B2 on the overall image G1, in which block regions of the same size as the single block region B2 are arranged at a certain interval T1. In step ST28, the block region setting unit 14 generates at least one piece of information from the size of each of the multiple block regions B2, the reference position of each of the multiple block regions B2, and the certain interval T1. Then, in step ST29, the block region setting unit 14 may receive input from the user and adjust the parameters of the size, reference position, and interval T1 of each of the multiple block regions B2.

[0063] In step ST13, at least one block region B2 out of a plurality of block regions B2 is inspected and data indicating the inspection result is generated (inspection step). Step ST13 includes steps ST30 to ST33. In step ST30, the selection reception unit 16 accepts the selection of at least one block region B2 to be inspected from among a plurality of block regions B2 set by the block region setting unit 14 (selection reception step). Subsequently, in step ST31, the inspection unit 17 derives the average brightness of the image of each light-emitting element S1 within the selected at least one block region B21, and derives an evaluation index from the absolute brightness and relative brightness for the address of each light-emitting element S1 (each light-emitting element). Then, in step ST32, the inspection unit 17 rearranges the light-emitting elements S1 in descending order of evaluation index, and determines that light-emitting elements S1 whose evaluation index is equal to or greater than the threshold are good products (good pixels), and light-emitting elements S1 whose evaluation index is less than the threshold are defective products (defective pixels). Then, in step ST33, the inspection unit 17 outputs data indicating the inspection result for each block region B21. The inspection unit 17 may output all inspection results for the selected block area B21, or it may output inspection results for the block area B21 selected by the user as the output target. The inspection unit 17 may display the data indicating the inspection results on the display unit 15, or it may transmit it to an external device.

[0064] [Operation and Effects] According to the inspection apparatus 1 described above, multiple block regions B2 are set from an overall image G1 of a wafer W containing multiple light-emitting elements S1, and at least one of these is inspected. By dividing the multiple light-emitting elements contained in the wafer into multiple block regions in advance, the multiple light-emitting elements S1 in each block region B2, which can be independent functional regions of each other, can be efficiently inspected.

[0065] The inspection device 1 further includes a segmented image setting unit 12 that sets an image of a single light-emitting element S1 as a reference image G2, divides the overall image G1 into regions corresponding to the size of the reference image G2 along the X and Y directions (predetermined directions), and sets a plurality of segmented images G3 arranged continuously along the predetermined directions, and a similarity calculation unit 13 that calculates the similarity between each of the plurality of segmented images G3 and the reference image G2, and a block region setting unit 14 that sets a plurality of block regions B2 based on the similarity. In this case, the segmented image setting unit 12 can easily determine the size of the segmented images G3 based on the reference image G2, and by arranging the segmented images G3 continuously along the X and Y directions, a plurality of segmented images G3 can be set efficiently and without omission for the overall image G1. Furthermore, based on the similarity calculated by the similarity calculation unit 13, the block region setting unit 14 can set the block regions B2 with high accuracy, thereby improving inspection accuracy.

[0066] The block region setting unit 14 determines that a segmented image G3 whose similarity exceeds the similarity threshold is a similar image of a single light-emitting element S1, and sets the region among the multiple segmented images G3 that is determined to be a similar image G4 in the X and Y directions as a single block region B2. As a result, the block region setting unit 14 sets multiple block regions B2 on the overall image G1, each block region being the same size as the single block region B2 and arranged at a constant interval T1. In this case, since the block region setting unit 14 determines the similar image G4 based on the similarity of each segmented image G3, visual judgment by the user is unnecessary, improving inspection efficiency and suppressing variability in judgment results. The block region setting unit 14 can then accurately set the block region B2 as a region formed by a dense concentration of multiple light-emitting elements S1 in the region that is determined to be a similar image G4 in the X and Y directions. If the series of processes from setting multiple segmented images G3 to setting multiple block regions B2 is performed automatically, for example, a significant improvement in inspection efficiency can be achieved while maintaining high accuracy.

[0067] The block region setting unit 14 generates information on at least one of the following: the size of each of the multiple block regions B2, the reference position of the multiple block regions B2, and a fixed interval T1. In this case, by visually displaying the information on the multiple block regions B2, the block region setting unit 14 facilitates processing such as comparing it with information on multiple block regions B2 of another wafer W.

[0068] The segmented image setting unit 12 sets an image of a single light-emitting element S1 extracted from the overall image G1 as a reference image G2, and arranges segmented images G3 along a column region RV set based on the width WD of the reference image G2, and a row region RH set based on the height HT of the reference image G2. In this case, the segmented image setting unit 12 can arrange the segmented images G3 along the row region RH and the column region RV with high precision, and can set multiple segmented images G3 more efficiently and without omissions relative to the overall image G1.

[0069] The selection reception unit 16 accepts the selection of at least one block region B21 to be inspected from among the multiple block regions B2 set by the block region setting unit 14. In this case, by selecting the block region B2 to be inspected, the inspection time is shortened and multiple light-emitting elements S1 can be inspected more efficiently.

[0070] [Modified Version] In the embodiment described above, the inspection device 1 was described as an apparatus for inspecting a wafer W that includes a plurality of blocks B1. However, instead of a wafer W, the inspection device 1 may inspect a wafer in which a plurality of light-emitting elements S1 are formed on the entire surface, without including a plurality of blocks B1. Figure 12 is a flowchart showing an example of an inspection method of a modified version. Figure 12 is a flowchart showing an example of an inspection method when the inspection device 1 inspects a wafer in which a plurality of light-emitting elements S1 are formed on the entire surface. The flowchart in Figure 12 differs from the method for inspecting a wafer W in that it does not include steps ST26 to ST30 in the flowchart in Figure 11, it includes step ST34 between steps ST25 and ST31, and it includes step ST35 instead of step ST33.

[0071] In step ST34, after multiple segmented images G3 are arranged in step ST25, the selection reception unit 16 receives the area to be inspected on the wafer from the user. Figure 13 is a diagram showing an example of an overall image including the area to be inspected. In step ST34, the area SR to be inspected is set for the overall image G1 including the wafer Wa on which multiple light-emitting elements S1 are formed all over. In the example in Figure 13, the area SR is set so as to exclude the orientation flat area OR of the wafer Wa. In step ST31, an evaluation index is derived for the multiple light-emitting elements S1 within the set area SR, and in step ST32, the quality of the multiple light-emitting elements S1 within the set area SR is determined. Then, in step ST35, the inspection unit 17 outputs data indicating the inspection results for the set area SR.

[0072] 1...Inspection device, 11...Image acquisition unit, 12...Segmented image setting unit, 13...Similarity calculation unit, 14...Block region setting unit, 16...Selection reception unit, 17...Inspection unit, B...Block, B2, B21, B22...Block region, G1...Overall image, G2...Reference image, G3...Segmented image, G4...Similar image, HT...Height, RH...Row region, RV...Column region, S1...Light-emitting element, T1...Spacing, W, Wa...Wafer, WD...Width.

Claims

1. An inspection apparatus comprising: an image acquisition unit that acquires an overall image of a wafer including a plurality of blocks arranged at predetermined intervals, each of which includes a plurality of light-emitting elements; a block region setting unit that sets a plurality of block regions corresponding to the plurality of blocks in the overall image; and an inspection unit that inspects at least one of the plurality of block regions and generates data indicating the inspection result.

2. An inspection apparatus according to claim 1, further comprising: a segmented image setting unit that sets an image of a single light-emitting element as a reference image, divides the overall image into regions corresponding to the size of the reference image along a predetermined direction, and sets a plurality of segmented images arranged continuously along the predetermined direction; and a similarity calculation unit that calculates the similarity between each of the plurality of segmented images and the reference image, wherein the block region setting unit sets the plurality of block regions based on the similarity.

3. The inspection apparatus according to claim 2, wherein the block region setting unit determines that the divided images whose similarity exceeds the similarity threshold are similar images of the single light-emitting element, and sets the regions among the plurality of divided images that are determined to be similar images in a predetermined direction as a single block region, thereby setting a plurality of block regions on the overall image in which block regions of the same size as the single block region are arranged at regular intervals.

4. The inspection apparatus according to claim 3, wherein the block region setting unit generates at least one piece of information from the sizes of each of the plurality of block regions, the reference positions of the plurality of block regions, and the constant interval.

5. The inspection apparatus according to claim 3 or 4, wherein the segmented image setting unit sets an image of a single light-emitting element extracted from the overall image as the reference image, and arranges the segmented images along a column region set based on the width of the reference image and a row region set based on the height of the reference image.

6. The inspection apparatus according to any one of claims 1 to 5, further comprising a selection receiving unit that receives the selection of at least one block region to be inspected from among the plurality of block regions set by the block region setting unit.

7. An inspection method comprising: an image acquisition step of acquiring an overall image of a wafer including a plurality of blocks arranged at predetermined intervals, each of which includes a plurality of light-emitting elements; a block region setting step of setting a plurality of block regions corresponding to the plurality of blocks in the overall image; and an inspection step of inspecting at least one of the plurality of block regions and generating data indicating the inspection result.

8. The inspection method according to claim 7, further comprising: setting an image of a single light-emitting element as a reference image; dividing the overall image into regions corresponding to the size of the reference image along a predetermined direction to set a plurality of divided images arranged continuously along the predetermined direction; and calculating the similarity between each of the plurality of divided images and the reference image, wherein in the block region setting step, the plurality of block regions are set based on the similarity.

9. The inspection method according to claim 8, wherein in the block region setting step, the divided images whose similarity exceeds the similarity threshold are determined to be similar images of the single light-emitting element, and the regions of the plurality of divided images that are determined to be similar images in a predetermined direction are set as a single block region, thereby setting a plurality of block regions on the overall image in which block regions of the same size as the single block region are arranged at regular intervals.

10. The inspection method according to claim 9, wherein the block region setting step generates at least one piece of information from the size of each of the plurality of block regions, the reference position of the plurality of block regions, and the constant interval.

11. The inspection method according to claim 9 or 10, wherein in the segmented image setting step, an image of a single light-emitting element extracted from the overall image is set as the reference image, and the segmented images are arranged along a column region set based on the width of the reference image and a row region set based on the height of the reference image.

12. The inspection method according to any one of claims 7 to 11, further comprising a selection acceptance step for accepting the selection of at least one block region to be inspected from among the plurality of block regions set in the block region setting step.

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