Defect inspection method and defect inspection device

Abstract

A defect inspection method is provided that can efficiently and reliably detect cracks in through holes formed in a glass substrate in a short time. [Solution] A defect inspection method for detecting cracks in through holes 10 formed in a glass substrate 100, comprising an irradiation process of irradiating the glass substrate 100 with inspection light L1 via a first polarization unit 4, an imaging process of photographing the inspection light L1 irradiated to the glass substrate 100 via a second polarization unit 5, and an extraction process of extracting abnormal through holes 10 from the image captured in the imaging process.

Description

[Technical Field]

[0001] The present invention relates to a defect inspection method and a defect inspection device for detecting cracks in through holes formed in a glass substrate. [Background technology]

[0002] Semiconductor packages use interposers (relay substrates) to electrically connect multiple semiconductor chips to a substrate. Among these, glass interposers, which use a glass substrate as the core material of the interposer, have been attracting attention in recent years. Glass interposers have through holes formed in the glass substrate, and through electrodes are provided in these through holes. Normally, through holes are prone to cracking (fine cracks) when formed by irradiation with laser light, etc.

[0003] Conventionally, a method for inspecting cracks using image analysis has been proposed (see, for example, Patent Document 1). In the inspection method described in Patent Document 1, an image of a through hole is acquired, the diameter of the through hole is calculated, a through hole whose diameter is equal to or greater than a threshold value is selected as an inspection target through hole, and the presence or absence of a crack in the inspection target through hole is evaluated. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-053545 Summary of the Invention [Problem to be solved by the invention]

[0005] The inspection method of Patent Document 1 calculates the diameter for each through-hole, which results in a problem that the amount of data to be processed increases as the number of through-holes increases, and the defect inspection takes a long time. Also, the method lacks accuracy because it does not detect cracks in through-holes whose diameter is less than a threshold value.

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a defect inspection method and a defect inspection device that can detect cracks in through holes formed in a glass substrate efficiently and reliably in a short time. [Means for solving the problem]

[0007] The defect inspection method according to the present invention for solving the above problems is characterized by the following configuration: A defect inspection method for detecting cracks in a through hole formed in a glass substrate, comprising: an irradiation step of irradiating the glass substrate with inspection light via a first polarization unit; an imaging step of imaging the inspection light irradiated onto the glass substrate via a second polarization unit; an extraction step of extracting abnormal through holes from the image captured in the imaging step; The purpose is to encompass the above.

[0008] According to this defect inspection method, the irradiated inspection light passes through the first polarization unit in the irradiation step and is incident on the glass substrate with its polarization direction aligned. If a crack occurs in a through hole formed in the glass substrate, the inspection light incident on the glass substrate is scattered (refracted) by the crack. Next, in the photographing step, the inspection light irradiated on the glass substrate is photographed through the second polarization unit. This photograph captures only the inspection light that passed through the second polarization unit, resulting in a brightness image that clearly shows areas with and without cracks. Therefore, in the extraction step, abnormal through holes can be extracted from the image (brightness image) photographed in the photographing step. As a result, multiple through holes formed in the glass substrate can be inspected at once, enabling cracks in the through holes formed in the glass substrate to be detected efficiently in a short time.

[0009] In the defect inspection method according to the present invention, the first polarizing unit and the second polarizing unit include linear polarizers, The first polarizing unit and the second polarizing unit are preferably arranged such that their polarization directions intersect when viewed from the incident direction of the inspection light.

[0010] According to the defect inspection method of this configuration, the first polarization unit includes a linear polarizer, which converts the inspection light irradiated onto the glass substrate in the irradiation step into linearly polarized light. The first polarization unit and the second polarization unit are arranged so that their polarization directions intersect when viewed from the direction of incidence of the inspection light. Therefore, the inspection light incident on areas where no cracks have occurred does not pass through the second polarization unit, and the inspection light (scattered light) incident on areas where cracks have occurred passes through the second polarization unit. Therefore, the photographing step obtains a light-dark image in which areas where cracks have occurred (bright areas) and areas where no cracks have occurred (dark areas) are clearly visible, making it easy to identify through holes with abnormalities.

[0011] In the defect inspection method according to the present invention, The first polarizing unit and the second polarizing unit are preferably arranged so that their polarization directions are orthogonal to each other when viewed from the incident direction of the inspection light.

[0012] According to the defect inspection method of this configuration, the first polarization unit and the second polarization unit are arranged so that their polarization directions are orthogonal to each other when viewed from the direction of incidence of the inspection light. Therefore, the inspection light incident on areas where no cracks have occurred does not pass through the second polarization unit, while the inspection light (scattered light) incident on areas where cracks have occurred passes through the second polarization unit. Therefore, in the image (bright / dark image) captured in the photographing process, the areas where cracks have occurred (bright areas) appear bright, making the cracks in the through holes clearly visible. This allows for reliable detection of cracks in through holes formed in the glass substrate. Furthermore, by arranging the polarization directions of the first polarization unit and the second polarization unit so that they are orthogonal to each other when viewed from the direction of incidence of the inspection light, the difference in brightness between the areas where cracks have occurred (bright areas) and the areas where no cracks have occurred (dark areas) becomes more distinct. This allows for efficient detection of cracks in through holes formed in the glass substrate in a short time.

[0013] In the defect inspection method according to the present invention, The first polarizing unit and / or the second polarizing unit preferably includes a liquid crystal layer.

[0014] According to the defect inspection method of this configuration, since the first polarizing unit and / or the second polarizing unit includes a liquid crystal layer, it is easy to control the polarization direction of the first polarizing unit and / or the second polarizing unit, and as a result, cracks in through holes formed in a glass substrate can be detected efficiently in a short time.

[0015] In the defect inspection method according to the present invention, It is preferable that the method further includes a rotation step of relatively rotating the polarization direction of the first polarizing unit or the second polarizing unit.

[0016] According to the defect inspection method of this configuration, the rotation process rotates the polarization direction of the first polarizing unit or the second polarizing unit relative to one another, thereby switching the brightness of areas where cracks have occurred and areas where cracks have not occurred, making it easier to visually recognize areas where cracks have occurred (i.e., through holes with abnormalities).

[0017] In the defect inspection method according to the present invention, It is preferable that the method further comprises a determination step of determining whether or not there is a crack in the abnormal through hole extracted in the extraction step.

[0018] According to the defect inspection method of this configuration, the determination step determines whether or not there is a crack in the abnormal through hole extracted in the extraction step, so that cracks in the through hole can be reliably detected.

[0019] The defect inspection device according to the present invention for solving the above problems has the following characteristic configuration: A defect inspection device for detecting cracks in through holes formed in a glass substrate, an irradiation means for irradiating the glass substrate with inspection light; an imaging means for imaging the inspection light irradiated onto the glass substrate; a first polarization unit disposed between the glass substrate and the irradiation means; a second polarization unit disposed between the glass substrate and the imaging unit; extraction means for extracting abnormal through holes from the image captured by the imaging means; The purpose is to provide the following.

[0020] In this defect inspection device, the first polarization unit is disposed between the glass substrate and the irradiation unit. When the irradiation unit irradiates the glass substrate with inspection light, the inspection light that passes through the first polarization unit is incident on the glass substrate with the same polarization direction. If a crack occurs in a through hole formed in the glass substrate, the inspection light that enters the glass substrate is scattered (refracted) by the crack. Therefore, the polarization direction of the inspection light (scattered light) incident on the cracked area is broadened from the polarization direction of the inspection light (non-scattered light) incident on the non-cracked area. Furthermore, the second polarization unit is disposed between the glass substrate and the imaging unit. When the imaging unit captures the inspection light irradiated on the glass substrate, only the inspection light that passes through the second polarization unit is captured. This results in a brightness image that clearly shows the cracked and non-cracked areas. Therefore, the extraction unit can extract abnormal through holes from the image (brightness image) captured by the imaging unit. As a result, a plurality of through holes formed in the glass substrate can be inspected at once, and cracks in the through holes formed in the glass substrate can be detected efficiently in a short time.

[0021] The defect inspection device according to the present invention for solving the above problems has the following characteristic configuration: A defect inspection device for detecting cracks in through holes formed in a glass substrate, an illumination means including a liquid crystal module for irradiating the glass substrate with inspection light; an imaging means for imaging the inspection light irradiated onto the glass substrate; a second polarization unit disposed between the glass substrate and the imaging unit; extraction means for extracting abnormal through holes from the image captured by the imaging means; The purpose is to provide the following.

[0022] In this defect inspection device, the irradiating unit includes a liquid crystal module that irradiates inspection light. Therefore, the inspection light irradiated by the liquid crystal module is incident on the glass substrate with its polarization direction aligned. If a crack is present in a through hole formed in the glass substrate, the inspection light incident on the glass substrate is scattered (refracted) by the crack. Therefore, the polarization direction of the inspection light (scattered light) incident on the cracked area is broadened from the polarization direction of the inspection light (non-scattered light) incident on the crack-free area. Furthermore, since the second polarizing unit is disposed between the glass substrate and the imaging unit, when the imaging unit captures the inspection light irradiated on the glass substrate, only the inspection light that passes through the second polarizing unit is captured, resulting in a brightness image that clearly shows the cracked and non-cracked areas. Therefore, the extracting unit can extract abnormal through holes from the image (brightness image) captured by the imaging unit. As a result, multiple through holes formed in the glass substrate can be inspected at once, enabling efficient detection of cracks in the through holes formed in the glass substrate in a short time. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is an explanatory diagram of a glass substrate, where (a) is a plan view of the glass substrate and (b) is a cross-sectional view taken along the line AA in (a). [Figure 2] FIG. 2 is a schematic diagram of the defect inspection device of the present invention. [Figure 3] FIG. 3 is an explanatory diagram of a case where the first polarizing unit and the second polarizing unit are arranged so that their polarization directions intersect. [Figure 4] Figure 4 is an example of an image of a through hole captured by a photographing means in a state in which the first polarizing unit and the second polarizing unit are arranged so that their polarization directions are perpendicular to each other when viewed from the incident direction of the inspection light L1. [Figure 5] FIG. 5 is a flowchart showing the procedure of the defect inspection method of the present invention. [Figure 6] FIG. 6 is a schematic diagram of a defect inspection device according to another embodiment 1 of the present invention. [Figure 7]FIG. 7 is a schematic diagram of a defect inspection device according to another embodiment 2 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a defect inspection method and a defect inspection apparatus according to the present invention will be described in detail with reference to the drawings. However, the present invention is not intended to be limited to the configurations described below.

[0025] [Glass substrate] Before describing the defect inspection method and defect inspection device of the present invention, a glass substrate to be inspected by the defect inspection method and defect inspection device of the present invention will be described. Figure 1 is an explanatory diagram of a glass substrate 100, where (a) is a plan view of the glass substrate 100 and (b) is a cross-sectional view taken along the line AA in (a).

[0026] The glass substrate 100 is a substrate used as a glass interposer (glass core substrate) with a plurality of through holes 10 formed therein and electrodes provided in the through holes 10. In this embodiment, the thickness of the glass substrate 100 can be appropriately set within the range of, for example, 100 μm to 1 mm.

[0027] The through hole 10 is a hole that penetrates through an opening 10a disposed on the upper surface 100a of the glass substrate 100 and an opening 10b disposed on the lower surface 100b. The through hole 10 formed in the glass substrate 100 is also called a through glass via (TGV). In this embodiment, the through hole 10 is formed by etching from both the upper surface 100a and the lower surface 100b of the glass substrate 100 after irradiating it with laser light. Therefore, as shown in FIG. 1(b), the shape of the through hole 10 has an orifice portion 10c (an hourglass shape with a narrowed central portion in the central axis direction of the through hole 10). In this embodiment, the diameters of the openings 10a and 10b are appropriately set in the range of 10 μm to 500 μm, and the diameter of the orifice portion 10c is appropriately set in the range of 5 μm to 250 μm. The means and shape of the through hole 10 are not particularly limited. For example, the through hole 10 may be formed by processing only with irradiation of laser light, and the cross section of the opening 10a and the opening 10b may have a tapered shape with different diameters.

[0028] [Defect inspection device] FIG. 2 is a schematic diagram of a defect inspection apparatus 1A of the present invention. The defect inspection apparatus 1A is an apparatus that detects cracks in through holes 10 formed in a glass substrate 100 to be inspected. As shown in FIG. 2, the defect inspection apparatus 1A includes an irradiation means 2, an imaging means 3, a first polarization unit 4, a second polarization unit 5, and an extraction means 6. The defect inspection apparatus 1A also includes a driving means 7 as an optional component. The operations of the irradiation means 2, the imaging means 3, the extraction means 6, and the driving means 7 are controlled by a control means 8. Each component of the defect inspection apparatus 1A will be described in detail below.

[0029] <Irradiation means> The irradiation means 2 is a means for irradiating the glass substrate 100 with the inspection light L1. In this embodiment, the irradiation means 2 is disposed so as to be able to irradiate the inspection light L1 onto the underside 100b of the glass substrate 100. As the irradiation means 2, it is preferable to use a planar light source (e.g., an LED, an organic EL element, etc.) that emits light uniformly, and in particular, an LED (especially a monochromatic LED) is preferable. By employing a planar LED as the light source of the inspection light L1, it is possible to irradiate the entire or most of the glass substrate 100 at once.

[0030] <Method of shooting> The imaging means 3 is a means for receiving (taking an image of) the inspection light L1 irradiated onto the glass substrate 100. In this embodiment, the imaging means 3 is disposed so as to be able to take an image of the upper surface 100a of the glass substrate 100. The imaging means 3 may be a digital camera having an image sensor in which solid-state imaging elements such as CCDs (Charged-Coupled Devices) and CMOSs ​​(Complementary Metal-Oxide-Semiconductors) are arranged in a two-dimensional array, and the image sensor detects the light incident on the imaging means 3. The imaging means 3 records the captured image in a storage device (not shown), such as a hard disk.

[0031] The imaging means 3 is preferably configured to be movable so that any position on the glass substrate 100 can be imaged from the normal direction of the substrate surface. In this embodiment, the imaging means 3 images an area R of any position and size on the glass substrate 100, as shown in Fig. 2, and acquires an image. Multiple images of a predetermined size can be captured while changing the imaging position on the glass substrate 100, and these images can be combined to create an image of the entire glass substrate 100.

[0032] <First Polarizing Unit and Second Polarizing Unit> As shown in FIG. 2, the first polarization unit 4 is disposed between the glass substrate 100 and the irradiation means 2. By disposing the first polarization unit 4 between the glass substrate 100 and the irradiation means 2, the inspection light L1 irradiated by the irradiation means 2 passes through the first polarization unit 4 and enters the glass substrate 100. As shown in FIG. 2, the second polarization unit 5 is disposed between the glass substrate 100 and the imaging means 3. By disposing the second polarization unit 5 between the glass substrate 100 and the imaging means 3, the inspection light L1 that has passed through the first polarization unit 4 passes through the second polarization unit 5 and enters the imaging means 3. In this manner, the glass substrate 100 to be inspected is photographed.

[0033] In this embodiment, the first polarizing unit 4 includes a linear polarizer 41, and the second polarizing unit 5 includes a linear polarizer 51. The linear polarizers 41 and 51 are not particularly limited as long as they transmit linearly polarized light having a specific vibration direction, and examples thereof include an absorptive polarizer and a reflective polarizer. The absorptive polarizer has the function of absorbing light vibrating in a specific direction and transmitting polarized light vibrating in a direction perpendicular to the specific direction (linearly polarized light). Examples thereof include a polarizer in which a film of uniaxially stretched polyvinyl alcohol having iodine compound molecules adsorbed thereon is sandwiched between triacetyl cellulose (TAC), a dye polarizer, and a coating-type polarizer. The reflective polarizer has the function of reflecting light vibrating in a specific direction and transmitting polarized light vibrating in a direction perpendicular to the specific direction (linearly polarized light). Examples thereof include a multilayer reflective polarizer (product name: DBEF) manufactured by Sumitomo 3M Limited and a wire grid polarizer in which thin metal wires are arranged.

[0034] Since the first polarization unit 4 includes the linear polarizer 41, the inspection light L1 that passes through the first polarization unit 4 is converted into linearly polarized light. That is, when the inspection light L1 irradiated by the irradiation means 2 enters the first polarization unit 4, only the inspection light L1 having a predetermined polarization direction is emitted, and therefore the inspection light L1 enters the glass substrate 100 with its polarization direction aligned.

[0035] Since the second polarization unit 5 includes the linear polarizer 51, only the inspection light L1 having a predetermined polarization direction passes through the second polarization unit 5. Therefore, when the inspection light L1 irradiated onto the glass substrate 100 is photographed by the imaging means 3, only the inspection light L1 that has passed through the second polarization unit 5 out of the inspection light L1 irradiated onto the glass substrate 100 is photographed, and therefore a light-dark image is obtained in which areas with and without cracks are clearly visible.

[0036] As shown in FIG. 2, the first polarization unit 4 and the second polarization unit 5 are preferably arranged so that their polarization directions intersect when viewed from the incident direction of the inspection light L1. FIG. 3 is an explanatory diagram of a case where the first polarization unit 4 and the second polarization unit 5 are arranged so that their polarization directions intersect when viewed from the incident direction of the inspection light L1. For simplicity of explanation, FIG. 3 omits the through-hole 10 in the glass substrate 100 and only illustrates the crack X. As indicated by arrows a and b in FIG. 3, the inspection light L1 irradiated by the irradiation unit 2 passes through the first polarization unit 4 and enters the glass substrate 100 with its polarization direction aligned. Here, if a crack X occurs in the through-hole 10 formed in the glass substrate 100, a gap is created at that portion, and the inspection light L1 incident on the glass substrate 100 changes from a state in which the polarization direction was aligned to a state in which it includes light with an inaligned direction. Therefore, if a crack X occurs in a through hole 10 formed in the glass substrate 100, the inspection light L1 incident on the glass substrate 100 is scattered (refracted) by the crack X, and the polarization direction of the inspection light (scattered light) L1 incident on the region where the crack X occurs is wider than the polarization direction of the inspection light (non-scattered light) L1 incident on the region where the crack X does not occur. As a result, when the first polarization unit 4 and the second polarization unit 5 are arranged so that their polarization directions intersect when viewed from the incident direction of the inspection light L1, the inspection light L1 that passes through the region where the crack X occurs passes through the second polarization unit 5, as shown by arrow a in FIG. 3. Furthermore, as shown by arrow b in FIG. 3, the inspection light L1 that passes through the region where the crack X does not occur hardly passes through the second polarization unit 5.

[0037] In this way, the inspection light L1 that passes through the area where no crack X has occurred hardly passes through the second polarization unit 5, and therefore cannot be captured by the imaging means 3, and appears dark in the image captured by the imaging means 3. On the other hand, the inspection light L1 that passes through the area where crack X has occurred is scattered by the crack X and passes through the second polarization unit 5, and therefore can be captured by the imaging means 3, and appears bright in the image captured by the imaging means 3. Therefore, the imaging means 3 can obtain a light-dark image in which the area where cracks have occurred (bright areas) and the area where cracks have not occurred (dark areas) are clearly visible, and therefore, through holes 10 with abnormalities can be easily extracted.

[0038] 4 is an example of an image of a through hole 10 captured by the imaging unit 3 in a state in which the first polarization unit 4 and the second polarization unit 5 are arranged so that their polarization directions are orthogonal to each other when viewed from the incident direction of the inspection light L1. If a crack occurs in the through hole 10 formed in the glass substrate 100, a bright area will appear around the through hole 10 in the light-dark image captured by the imaging unit 3, as shown in FIG. 4. By arranging the polarization directions of the first polarization unit 4 and the second polarization unit 5 so that they are orthogonal to each other when viewed from the incident direction of the inspection light L1, the difference in light and dark between the area where the crack occurs (bright area) and the area where no crack occurs (dark area) becomes clearer, making it possible to efficiently detect cracks in the through hole 10 formed in the glass substrate 100 in a short time.

[0039] Although not shown in the figures, the first polarization unit 4 and the second polarization unit 5 may be arranged so that their polarization directions are parallel to each other when viewed from the incident direction of the inspection light L1. When the first polarization unit 4 and the second polarization unit 5 are arranged so that their polarization directions are parallel to each other, the inspection light L1 that passes through an area where no cracks have occurred passes through the second polarization unit 5. On the other hand, the inspection light L1 that passes through an area where a crack has occurred is scattered by the cracks, causing the polarization direction of the inspection light L1 to become distorted and the polarization distribution to become broader, so that the inspection light L1 does not pass through the second polarization unit 5. Therefore, the imaging unit 3 can obtain a light-dark image in which areas where cracks have occurred (dark areas) and areas where no cracks have occurred (bright areas) are clearly visible.

[0040] In this way, since the first polarization unit 4 and the second polarization unit 5 include linear polarizers, the image captured by the imaging means 3 produces a light and dark image that clearly shows areas where cracks have occurred and areas where cracks have occurred, making it easy to extract abnormal through holes 10.

[0041] <Extraction means> The extraction means 6 extracts through holes 10 having an abnormality from the image (brightness image) captured by the imaging means 3. The extraction means 6 is implemented as a computer having a CPU, memory, storage, etc., in which the CPU reads and executes a program recorded in the memory. Specifically, the extraction means 6 performs image analysis on the image captured by the imaging means 3 to extract areas where the brightness differs from the surroundings, and extracts through holes 10 in which this area occurs as through holes 10 having an abnormality. The extraction of the areas can be performed, for example, by edge detection processing or the like.

[0042] <Drive means> The driving means 7 is a means for relatively rotating the polarization direction of the first polarization unit 4 or the second polarization unit 5. The driving means 7 includes mechanisms such as a motor and gears, and the rotation of the motor is controlled by the control means 8. In this embodiment, the driving means 7 fixes one of the first polarization unit 4 or the second polarization unit 5 and rotates the other. For example, if the second polarization unit 5 is fixed and the driving means 7 rotates the first polarization unit 4 relative to the second polarization unit 5 by a certain angle, the polarization direction of the inspection light L1 passing through the first polarization unit 4 changes, and the contrast of the bright / dark image changes as the amount of inspection light L1 passing through the second polarization unit 5 changes. Therefore, by relatively rotating the polarization direction of the first polarization unit 4 or the second polarization unit 5 using the driving means 7, the brightness of the cracked area and the crack-free area changes, making it easy to visually recognize the cracked area (i.e., the abnormal through hole 10). Furthermore, by using the driving means 7 to relatively rotate the polarization direction of the first polarization unit 4 or the second polarization unit 5 and acquiring multiple images in which the polarization directions of the first polarization unit 4 and the second polarization unit 5 are different, it becomes possible for the extraction means 6 to extract abnormal through holes 10 from the difference between the images. Note that the driving means 7 may be configured to be able to adjust the distance between the first polarization unit 4 and the second polarization unit 5 and the glass substrate 100 to be inspected.

[0043] <Control means> The control means 8 is a computer having a CPU, memory, storage, etc., and the CPU reads and executes a program recorded in the memory, thereby realizing the function of controlling the operations of the irradiation means 2, the photographing means 3, the extraction means 6, and the driving means 7.

[0044] [Defect inspection method] Figure 5 is a flowchart showing the steps of the defect inspection method of the present invention. In the defect inspection method of the present invention, the irradiation step, the photographing step, and the extraction step are performed in order using the defect inspection apparatus 1A of Figure 2, and further, as optional steps, a rotation step is performed before the extraction step, and a judgment step is performed after the extraction step. In the flowchart of Figure 5, each step of the defect inspection method is indicated by the symbol "S."

[0045] <Irradiation process: S1> In the irradiation step, the irradiation means 2 irradiates the glass substrate 100 with inspection light L1 via the first polarization unit 4. In the irradiation step, the irradiated inspection light L1 passes through the first polarization unit 4 and is incident on the glass substrate 100 with its polarization direction aligned. If a crack occurs in the through hole 10 formed in the glass substrate 100, the inspection light L1 incident on the glass substrate 100 is scattered (refracted) by the crack.

[0046] <Photography process: S2> In the photographing step, the photographing means 3 receives (photographs) the inspection light L1 irradiated onto the glass substrate 100 via the second polarization unit 5. In the photographing step, the photographing means 3 may photograph the entire glass substrate 100 all at once, or may photograph the glass substrate 100 divided into a plurality of regions. When the photographing step photographs the inspection light L1 irradiated onto the glass substrate 100 via the second polarization unit 5, only the inspection light L1 that has passed through the second polarization unit 5 out of the inspection light L1 irradiated onto the glass substrate 100 is photographed, and therefore a light-dark image in which areas with and without cracks are clearly visible is obtained.

[0047] <Rotation process: S3~S4> If the rotation step is to be performed (S3: YES), the polarization direction of the first polarization unit 4 or the second polarization unit 5 is relatively rotated by the driving means 7 (S4), and the process returns to S2 to perform the photographing step. By relatively rotating the polarization direction of the first polarization unit 4 or the second polarization unit 5 in the rotation step, the brightness of the area where a crack has occurred and the area where no crack has occurred are switched between light and dark, making it easier to visually recognize the area where a crack has occurred (i.e., the through hole 10 with an abnormality). If the rotation step is not to be performed (S3: NO), the process proceeds to the extraction step.

[0048] <Extraction process: S5> In the extraction step, abnormal through holes 10 are extracted from the image (brightness image) captured in the imaging step. By performing image analysis on the image captured in the imaging step, areas where the brightness differs from the surroundings are extracted, and through holes 10 in which such areas occur are extracted as abnormal through holes 10. The extraction of the areas can be performed by, for example, edge detection processing or the like.

[0049] <Judgment process: S6> In the determination step, the presence or absence of a crack is determined in the abnormal through hole 10 extracted in the extraction step. For example, the presence of a crack is determined when the brightness value around the abnormal through hole 10 in the light-dark image from which the abnormal through hole 10 has been extracted is equal to or greater than a threshold. Alternatively, the presence of a crack may be determined when the shape of an area with different light and dark areas around the abnormal through hole 10 matches the shape of a predetermined crack. Note that, when the presence of a crack is determined in the determination step, it is preferable to display the position, size, range, etc. of the determined crack.

[0050] As described above, in the defect inspection method and defect inspection device of the present invention, by using the first polarization unit 4 and the second polarization unit 5, a light and dark image is obtained in which areas where cracks have occurred and areas where cracks have not occurred are clearly shown, so that multiple through holes 10 formed in the glass substrate 100 can be inspected at once, and cracks in the through holes 10 formed in the glass substrate 100 can be detected efficiently in a short period of time.

[0051] Although the defect inspection method and defect inspection device of the present invention have been described above based on one embodiment, the present invention is not limited to the configurations described in the above embodiments, and the configurations can be changed as appropriate within the scope of the spirit of the present invention. Specific other embodiments are as follows.

[0052] (Another embodiment 1) 6 is a schematic diagram of a defect inspection apparatus 1B according to another embodiment 1 of the present invention. In the above embodiment, an example has been shown in which the first polarization unit 4 or the second polarization unit 5 is rotated by the driving means 7, but the present invention is not limited to this, and the polarization direction of the first polarization unit 4 and / or the second polarization unit 5 may be rotated by including a liquid crystal layer in the first polarization unit 4 and / or the second polarization unit 5.

[0053] The first polarizing unit 4 in Alternative Embodiment 1 includes a linear polarizer 41 and a liquid crystal layer 42. As shown in FIG. 6, the liquid crystal layer 42 is laminated on the upper surface (glass substrate 100 side) of the linear polarizer 41. The liquid crystal layer 42 has liquid crystal molecules sandwiched between transparent plates. When a voltage is applied, the orientation of the molecules changes, thereby controlling the transmittance and polarization state of light. Therefore, the polarization direction of the inspection light L1 after passing through the linear polarizer 41 can be changed depending on the applied voltage. In Alternative Embodiment 1, as shown in FIG. 6, when the linear polarizer 41 and the second polarizing unit 5 are arranged so that their polarization directions are parallel to each other, the polarization directions of the first polarizing unit 4 and the second polarizing unit 5 are parallel to each other when no voltage is applied to the liquid crystal layer 42. However, when a voltage is applied to the liquid crystal layer 42, the polarization directions of the first polarizing unit 4 and the second polarizing unit 5 cross each other. That is, when a voltage is applied to the liquid crystal layer 42, most of the inspection light L1 that passes through areas where no cracks have occurred does not pass through the second polarization unit 5, and the inspection light L1 that passes through areas where cracks have occurred passes through the second polarization unit 5, thereby obtaining an image in which the brightness of areas where cracks have occurred differs from that of areas where no cracks have occurred. Furthermore, by including the liquid crystal layer 42, it is also possible to configure the polarization direction of the first polarization unit 4 and / or the second polarization unit 5 to rotate relatively depending on the voltage applied to the liquid crystal layer 42.

[0054] The linear polarizer 41 and the second polarizer 5 may be arranged so that their polarization directions intersect, in which case, when no voltage is applied to the liquid crystal layer 42, the polarization directions of the first polarizer 4 and the second polarizer 5 intersect, but when a voltage is applied to the liquid crystal layer 42, the polarization directions of the first polarizer 4 and the second polarizer 5 become parallel. In addition, although the first embodiment is configured so that the liquid crystal layer 42 is included in the first polarizer 4, it may also be configured so that the second polarizer 5 includes the liquid crystal layer 42.

[0055] In this way, by including a liquid crystal layer in the first polarizing unit 4 and / or the second polarizing unit 5, it becomes easy to control the polarization direction of the first polarizing unit 4 and / or the second polarizing unit 5. As a result, cracks in the through-hole 10 formed in the glass substrate 100 can be detected efficiently in a short time.

[0056] (Alternative embodiment 2) 7 is a schematic diagram of a defect inspection apparatus 1C according to another embodiment 2 of the present invention. In the above embodiment, the apparatus includes the irradiation means 2 and the first polarization unit 4, but the present invention is not limited to this, and the irradiation means 2 may be configured to include a liquid crystal module.

[0057] In another embodiment 2, the irradiation means 2 includes a liquid crystal module. The liquid crystal module includes a liquid crystal panel and a backlight. In the liquid crystal panel, a liquid crystal layer is sandwiched between two polarizing plates whose polarization directions are orthogonal to each other. An alignment film is disposed between each of the two polarizing plates and the liquid crystal layer. Since the irradiation means 2 includes the liquid crystal module, the inspection light L1 irradiated from the irradiation means 2 is emitted with the polarization direction aligned, which eliminates the need for the first polarization unit 4 shown in FIG. 2 and simplifies the configuration of the device. [Industrial Applicability]

[0058] The defect inspection method and defect inspection device of the present invention can be used in the manufacturing process of semiconductor packages, glass interposers, and the like. [Explanation of symbols]

[0059] 1A, 1B, 1C defect inspection equipment 2 Irradiation means 3. Filming methods 4 First polarizing section 5 Second polarization unit 6 Extraction means 7. Driving means 8 Control Means 41, 51 Linear polarizer 42 Liquid crystal layer 100 Glass substrate L1 Inspection light

Claims

1. A defect inspection method for detecting cracks around a through hole formed in a glass substrate used as a glass interposer, comprising: an irradiation step of irradiating the glass substrate with inspection light via a first polarization unit; an imaging step of capturing the area where the crack has occurred as a bright area by imaging the inspection light that has been irradiated onto the glass substrate and passed through the area where the crack has occurred via a second polarization unit; an extraction step of extracting, from the image captured in the photographing step, a through hole having an area with a different brightness from its surroundings as an abnormal through hole; It encompasses the first polarizing unit and the second polarizing unit include linear polarizers, A defect inspection method, wherein the first polarization unit and the second polarization unit are arranged so that their polarization directions intersect when viewed from the incident direction of the inspection light.

2. The defect inspection method according to claim 1 , wherein the first polarizing unit and the second polarizing unit are arranged so that their polarization directions are orthogonal to each other when viewed from the incident direction of the inspection light.

3. The defect inspection method according to claim 1 , wherein the first polarizing unit and / or the second polarizing unit includes a liquid crystal layer.

4. 2. The defect inspection method according to claim 1, further comprising a rotation step of fixing one of the first polarizing unit and the second polarizing unit and rotating the other polarizing unit relative to the other polarizing unit.

5. 2. The defect inspection method according to claim 1, further comprising a determining step of determining whether or not a crack exists in the abnormal through hole extracted in the extracting step.

6. A defect inspection device for detecting cracks around a through hole formed in a glass substrate used as a glass interposer, comprising: an irradiation means for irradiating the glass substrate with inspection light; an imaging means for capturing the area where the crack has occurred as a bright area by imaging inspection light that has been irradiated onto the glass substrate and passed through the area where the crack has occurred; a first polarization unit disposed between the glass substrate and the irradiation means; a second polarization unit disposed between the glass substrate and the imaging unit; an extraction means for extracting, in the image captured by the imaging means, a through hole having an area with a different brightness from its surroundings as an abnormal through hole; Equipped with the first polarizing unit and the second polarizing unit include linear polarizers, The defect inspection device is configured such that the first polarization unit and the second polarization unit have mutually intersecting polarization directions when viewed from the incident direction of the inspection light.

7. A defect inspection device for detecting cracks around a through hole formed in a glass substrate used as a glass interposer, comprising: an illumination means including a liquid crystal module for irradiating the glass substrate with inspection light; an imaging means for capturing the area where the crack has occurred as a bright area by imaging inspection light that has been irradiated onto the glass substrate and passed through the area where the crack has occurred; a second polarization unit disposed between the glass substrate and the imaging unit; an extraction means for extracting, in the image captured by the imaging means, a through hole having an area with a different brightness from its surroundings as an abnormal through hole; Equipped with the liquid crystal module and the second polarizing unit include a linear polarizer; The defect inspection device is configured such that the liquid crystal module and the second polarization unit are arranged such that their polarization directions intersect when viewed from the incident direction of the inspection light.

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