Wafer bonding force test apparatus and method

Abstract

The present invention relates to a bonding strength inspection device and may include: a light-emitting device that irradiates light toward a bonding surface of wafers or substrates bonded together; an image detection device that detects an optical image of the bonding surface with respect to the light generated by the light-emitting device; and a control unit that determines the bonding state of the bonding surface based on the optical image applied from the image detection device.

Description

Technology Field

[0001] The present invention relates to an apparatus and method for inspecting bonding strength, and more specifically, to an apparatus and method for inspecting bonding strength that enables accurate inspection of the bonding strength of wafers or substrates in a non-destructive manner by utilizing optical images using infrared or short-wave infrared rays. Background Technology

[0002] When bonding wafer to wafer or die to wafer, the presence of voids, bubbles, or foreign substances on the bonding surface between the bonded wafers or substrates can cause a significant decrease in the strength of the bonding surface.

[0003] Conventionally, to verify the phenomenon of strength degradation at the bonding surface, a destructive wafer bonding strength inspection device that physically destroys a part of the wafers—such as by forcibly inserting a blade into the bonding surface at the edge of the bonded wafers to destroy the bonding surface while measuring the resistance value—is widely used. The problem to be solved

[0004] However, these conventional wafer bonding strength inspection devices could only measure the bonding strength at the edges of the wafers and could not measure the overall bonding strength distribution of the bonding surface. Furthermore, since a separate inspection device for mechanically destroying wafers is relatively expensive, inspection costs increased; wafers were wasted because they were destroyed after inspection; and inspection productivity was significantly reduced due to the long inspection time required.

[0005] The present invention aims to solve various problems, including those mentioned above, by providing a bonding strength inspection device and method that enable accurate inspection of the bonding strength of the bonding surfaces of wafers or substrates in a non-destructive manner using optical images utilizing infrared or short-wave infrared radiation. However, this objective is exemplary and does not limit the scope of the present invention. means of solving the problem

[0006] A bonding strength inspection device according to the concept of the present invention for solving the above problem may include: a light-emitting device that irradiates light toward the bonding surface of wafers or substrates bonded together; an image detection device that detects an optical image of the bonding surface with respect to the light generated by the light-emitting device; and a control unit that determines the bonding state of the bonding surface based on the optical image applied from the image detection device.

[0007] In addition, according to the present invention, the light may include infrared light or short-wave infrared light.

[0008] In addition, according to the present invention, the optical image may be a two-dimensional planar image that includes the entire area of ​​the bonding surface and is displayed as a difference in brightness of the image depending on the difference in partial bonding force of the bonding surface or the presence or absence of bubbles or foreign substances.

[0009] In addition, according to the present invention, the optical image may be a three-dimensional shape image that includes the entire area of ​​the bonding surface and is displayed three-dimensionally according to differences in partial surface shape of the bonding surface or the shape of bubbles or foreign substances.

[0010] In addition, according to the present invention, the control unit can determine the bonding strength or defect status by determining the optical image based on a bonding strength database for each brightness that is pre-matched according to the reference brightness of the image.

[0011] In addition, according to the present invention, the control unit may include an artificial intelligence model that learns training images in a deep learning manner and determines the bonding strength or defect by distinguishing the optical image.

[0012] In addition, according to the present invention, the image sensing device may be a transmissive sensing device that detects light transmitted through the bonding surface or a reflective sensing device that detects light reflected by the bonding surface.

[0013] In addition, according to the present invention, the image sensing device may be an overall image sensing device installed above or below the bonding surface and capable of capturing an entire image of the bonding surface.

[0014] In addition, according to the present invention, the image sensing device may be a partial image sensing device capable of capturing a partial image of the bonding surface by means of a scan transfer device capable of moving along the bonding surface or moving the bonding surface.

[0015] In addition, according to the present invention, the control unit may receive a brightness signal from a brightness sensor installed around the wafer or substrates or receive a brightness signal from the optical image, and may apply a brightness control signal to the light-emitting device to adjust the brightness of the light so as to improve the identification power of the optical image.

[0016] In addition, according to the present invention, the control unit may receive a frequency signal from a frequency sensor installed around the wafer or substrates or receive a frequency signal from the optical image, and may apply a frequency control signal that converts the frequency of light to the light-emitting device so as to improve the identification power of the optical image.

[0017] In addition, according to the present invention, the control unit may receive a thickness signal from a thickness measuring sensor installed around the wafer or substrates or receive a thickness signal from the optical image, and may apply a thickness-corresponding control signal to the light-emitting device to convert the brightness or frequency of the light so as to improve the identification power of the optical image.

[0018] In addition, according to the present invention, the image detection device may be installed vertically upward or vertically downward with respect to the bonding surface.

[0019] Additionally, according to the present invention, the image sensing device may include a first camera installed at a first angle in a first direction with respect to the vertically upward or vertically downward direction of the bonding surface.

[0020] Additionally, according to the present invention, the image sensing device may include a second camera installed at a second angle different from the first angle of the first direction with respect to the vertically upward or vertically downward direction of the bonding surface.

[0021] Additionally, according to the present invention, the image sensing device may further include a third camera installed at a third angle in a second direction different from the first direction, based on the vertically upward or vertically downward direction of the bonding surface.

[0022] Additionally, according to the present invention, the image sensing device may include a movable camera in which the irradiation angle is changed by an angle moving device that moves from a fourth angle to a fifth angle in a first direction relative to the vertically upward or vertically downward direction of the bonding surface.

[0023] In addition, according to the present invention, a rotating device for rotating the wafers or substrates joined together so as to detect the optical image at various angles may be further included.

[0024] Meanwhile, a bonding strength inspection method according to the concept of the present invention for solving the above problem may include: (a) a step of irradiating light toward the bonding surface of wafers or substrates bonded together; (b) a step of detecting an optical image of the bonding surface with respect to the light; and (c) a step of determining the bonding state of the bonding surface using a past database or a learned artificial intelligence model based on the optical image.

[0025] Meanwhile, a bonding strength inspection device according to the concept of the present invention for solving the above problem comprises: a light-emitting device that irradiates light toward the bonding surface of wafers or substrates bonded together; and an image detection device that detects an optical image of the bonding surface with respect to the light generated by the light-emitting device. The apparatus includes a control unit that determines the bonding state of the bonding surface based on the optical image applied from the image detection device, wherein the light includes infrared light or short-wave infrared light, and the optical image is a two-dimensional planar image that includes the entire area of ​​the bonding surface and is displayed as a difference in brightness of the image according to a difference in partial bonding force of the bonding surface or the presence or absence of bubbles or foreign substances, or a three-dimensional shape image that includes the entire area of ​​the bonding surface and is displayed three-dimensionally according to a difference in partial surface shape of the bonding surface or the shape of bubbles or foreign substances, and the control unit may include an artificial intelligence model that determines the bonding force or defects by determining the optical image based on a bonding force database matched in advance according to the reference brightness of the image, or learns training images in a deep learning manner and determines the bonding force or defects by determining the optical image. Effects of the invention

[0026] According to various embodiments of the present invention as described above, the bonding strength of the bonding surfaces of wafers or substrates can be accurately inspected in a non-destructive manner by utilizing optical images using infrared or short-wave infrared rays. Furthermore, the overall bonding strength distribution of the bonding surfaces between wafers or substrates, as well as the presence and location of voids, bubbles, or foreign substances, can be accurately measured. Since optical devices such as light-emitting devices or image detection devices are relatively easy to develop and inexpensive, inspection costs can be significantly reduced. Additionally, because the wafers or substrates can be utilized as is after non-destructive inspection, the process is highly economical. Moreover, the short image detection and analysis times allow for significantly increased inspection efficiency and productivity. Of course, the scope of the present invention is not limited by these effects. Brief explanation of the drawing

[0027] FIG. 1 is a conceptual side view illustrating a bonding strength inspection device according to some embodiments of the present invention. FIG. 2 is a conceptual side view illustrating a bonding strength inspection device according to some other embodiments of the present invention. FIG. 3 is a conceptual side view illustrating a bonding strength inspection device according to some other embodiments of the present invention. FIG. 4 is a conceptual side view illustrating a bonding strength inspection device according to some other embodiments of the present invention. FIG. 5 is a conceptual side view illustrating a bonding strength inspection device according to some other embodiments of the present invention. FIG. 6 is a conceptual perspective view illustrating a bonding strength inspection device according to some other embodiments of the present invention. FIG. 7 is a conceptual side view illustrating a bonding strength inspection device according to some other embodiments of the present invention. FIG. 8 is a conceptual perspective view illustrating a bonding strength inspection device according to some other embodiments of the present invention. FIG. 9 is a flowchart illustrating a bonding strength inspection method according to some embodiments of the present invention. FIGS. 10 and FIGS. 11 are photographs showing examples of optical images of a bonding force inspection device according to some embodiments of the present invention. Specific details for implementing the invention

[0028] Hereinafter, several preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0029] The embodiments of the present invention are provided to more fully explain the invention to those skilled in the art, and the following embodiments may be modified in various different forms, and the scope of the invention is not limited to the following embodiments. Rather, these embodiments are provided to make the disclosure more faithful and complete and to fully convey the spirit of the invention to those skilled in the art. In addition, the thickness or size of each layer in the drawings is exaggerated for convenience and clarity of explanation.

[0030] The terms used herein are for describing specific embodiments and are not intended to limit the invention. As used herein, the singular form may include the plural form unless the context clearly indicates otherwise. Additionally, as used herein, "comprise" and / or "comprising" specify the presence of the mentioned features, numbers, steps, actions, parts, elements, and / or groups thereof, and do not exclude the presence or addition of one or more other features, numbers, actions, parts, elements, and / or groups.

[0031] Hereinafter, embodiments of the present invention are described with reference to drawings that schematically illustrate ideal embodiments of the present invention. In the drawings, variations of the illustrated shapes may be expected, for example, depending on manufacturing techniques and / or tolerances. Accordingly, embodiments of the inventive concept should not be interpreted as being limited to specific shapes of the areas illustrated herein, but should include, for example, variations in shape resulting from manufacturing.

[0032] FIG. 1 is a conceptual side view illustrating a bonding strength inspection device (100) according to some embodiments of the present invention.

[0033] First, as illustrated in FIG. 1, a bonding strength inspection device (100) according to some embodiments of the present invention may largely include a light-emitting device (10), an image detection device (20), and a control unit (30).

[0034] The light-emitting device (10) may be a type of lighting device that irradiates light toward the bonding surface (F) of various substrates, such as wafers (W1) (W2) or multilayer circuit boards or display panels that are bonded together, for example.

[0035] The light-emitting device (10) can be any of the various light-emitting elements that generate light including infrared light or short-wave infrared light, as shown in FIG. 1, infrared light-emitting elements, infrared LEDs (Light Emitted Diodes), infrared lamps, etc.

[0036] Such infrared illumination devices are capable of detecting features that cannot be perceived in visible light, and the infrared rays used for infrared illumination can include Near Infrared Ray (NIR) and Short Wavelength Infrared Ray (SWIR).

[0037] Infrared light is light with a wavelength range of approximately 700 nm to 1 mm, and is longer than 760 nm to 830 nm, which is called the upper limit of human vision, and is almost imperceptible to humans.

[0038] The wavelength range used for image processing in the present invention is a wavelength range called near-infrared or short-wave infrared, and the wavelength range that can be used varies depending on the light receiving element of the image detection device (20), and a wavelength suitable for the bonding surface of the wafer or substrate to be detected can be set and a camera and lighting can be selected.

[0039] Near-infrared rays have a wavelength range of 750 nm to 1000 nm and can penetrate the surface of wafers or substrates that interferes with the inspection of the bonding surface of the wafers or substrates.

[0040] Short-wave infrared rays have a wavelength range of 1000 nm to 2500 nm, and depending on the wavelength range, they can penetrate the surface of wafers or substrates as well as the wafers or substrates.

[0041] Since short-wave infrared rays are absorbed by water, it is possible to determine the presence or absence of moisture, pores, bubbles, or other foreign substances. For example, water absorbs light at 1450 nm and appears black in optical images, and thus, pores, bubbles, foreign substances, or moisture can be determined by utilizing the difference in transmittance of materials by wavelength.

[0042] The image detection device (20) may be any of the various image detection devices, such as an image detection element, an image detection sensor, an image detection camera, or an image spectroscopic device, which detect an optical image of a bonding surface (F) for light generated from a light-emitting device (10).

[0043] This image detection device (20) may be equipped with various optical components such as light receiving elements of various shapes or materials, lenses, or band-pass filters so as to be able to receive infrared light or short-wave infrared light.

[0044] The control unit (30) can be any of the various control devices, such as a computing device, a signal processing device, a central processing unit, a microprocessor, a semiconductor chip, an integrated circuit, a substrate, a circuit board, an electronic component, a storage device where a program is stored, a computer, a server computer, a personal computer, a smartphone, a smart pad, a smart device, etc., that determine the bonding state of the bonding surface (F) based on an optical image applied from an image detection device (20).

[0045] The optical image may be a two-dimensional planar image that includes a part or the entire area of ​​the bonding surface (F) and is displayed as a difference in brightness of the image depending on the difference in partial bonding force of the bonding surface (F) or the presence or absence of bubbles or foreign substances.

[0046] However, the optical image is not necessarily limited to this and may be a three-dimensional shape image that includes a part or the entire area of ​​the bonding surface (F) and is displayed three-dimensionally according to the difference in the partial surface shape of the bonding surface (F) or the shape of bubbles or foreign substances.

[0047] The control unit (30) can determine the bonding strength or defects by determining the optical image based on a bonding strength database that is pre-matched according to the reference brightness of the image.

[0048] Such a brightness-based bonding strength database can be formed by partially acquiring optical images of the bonding surfaces (F) of wafers or substrates in advance by brightness, and matching the acquired partial optical images with bonding strength data measured by actual destructive methods.

[0049] In addition, the control unit (30) may include, for example, an artificial intelligence model that learns training images in a deep learning manner and determines whether there is a bonding force or a defect by distinguishing optical images.

[0050] For example, the control unit (30) can determine the bonding strength or defects by using an artificial intelligence model that has an accuracy of 95 percent or more, which is trained in a deep learning manner through a bonding strength database by brightness.

[0051] Such artificial intelligence models can utilize various neural network algorithms that mimic the principles and structures of human neural networks, such as ANN (Artificial Neural Network), DNN (Deep Neural Network), CNN (Convolutional Neural Network), and RNN (Recurrent Neural Network).

[0052] The image detection device (20) may be a transmissive detection device (21) that detects light transmitted through the bonding surface (F), for example, as shown in FIG. 1.

[0053] Additionally, the image detection device (20) may be an overall image detection device (23) that is installed above the bonding surface (F), as shown in FIG. 1, and is capable of capturing an entire image of the bonding surface (F).

[0054] Here, the light-emitting device (10) may be installed, for example, vertically below the bonding surface (F), and the image detection device (20) may be installed, for example, vertically above the bonding surface (F). However, this is not necessarily limited thereto, and it is also possible, for example, for the light-emitting device (10) to be installed vertically above the bonding surface (F) and the image detection device (20) to be installed vertically below the bonding surface (F).

[0055] Accordingly, using these transmission type detection device (21) and overall image detection device (23), light generated from a light-emitting device (10) with a uniform amount of light passes through the bonding surface (F) of the wafers (W1) (W2) bonded together, and a portion is absorbed by, for example, pores, bubbles, or foreign substances, causing a difference in brightness. The image detection device (20) detects this difference in brightness as an optical image, and the control unit (30) can determine the bonding state of the bonding surface (F) very accurately in a non-destructive manner using a past database or a learned artificial intelligence model based on the optical image.

[0056] Meanwhile, the control unit (30) may receive a brightness signal from a brightness sensor (S1) installed around wafers (W1) (W2) or substrates, for example as shown in FIG. 1, or receive a brightness signal from an optical image, and may apply a brightness control signal to the light-emitting device (10) to adjust the brightness of the light so as to improve the identification power of the optical image.

[0057] Accordingly, the control unit (30) can optimize the brightness of the light-emitting device (10) based on the brightness signal from the brightness sensor (S1) or the brightness signal of the optical image, because if the brightness signal value received from the brightness sensor (S1) is too low or too high, causing the optical image to become too dark or too bright, the ability to distinguish between light and dark of the optical image is greatly reduced.

[0058] Therefore, according to the present invention, since an optimal optical image can always be obtained for wafers or substrates of very diverse materials and shapes, the bonding strength can be determined very accurately.

[0059] Additionally, the control unit (30) may receive a frequency signal from a frequency sensor (S2) installed around wafers (W1)(W2) or substrates, for example as shown in FIG. 1, or receive a frequency signal from an optical image, and may apply a frequency control signal to the light-emitting device (10) to convert the frequency of light so as to improve the identification power of the optical image.

[0060] Accordingly, the control unit (30) can adjust the frequency of the light of the light-emitting device (10) to be optimized based on the frequency signal from the frequency sensor (S2) or the frequency signal of the optical image when the frequency signal value received from the frequency sensor (S2) is too low or too high, causing the transmittance according to the frequency to change and the ability to distinguish the optical image to be distinguished to decrease.

[0061] Therefore, according to the present invention, since an optimal optical image can always be obtained for wafers or substrates of very diverse materials and shapes, the bonding strength can be determined very accurately.

[0062] Additionally, the control unit (30) may receive a thickness signal from a thickness measuring sensor (S3) installed around wafers (W1)(W2) or substrates, as shown in FIG. 1, or receive a thickness signal from an optical image, and may apply a thickness-corresponding control signal to the light-emitting device (10) to convert the brightness of the light or the frequency of the light so as to improve the identification power of the optical image.

[0063] Accordingly, the control unit (30) can optimize the brightness of the light or the frequency of the light of the light-emitting device (10) based on the thickness signal from the thickness measurement sensor (S3) or the thickness signal of the optical image when the thickness signal value received from the thickness measurement sensor (S3) is too thin or too thick and the ability to distinguish the optical image is reduced.

[0064] Therefore, according to the present invention, since an optimal optical image can always be obtained for wafers or substrates of very diverse materials and shapes, the bonding strength can be determined very accurately.

[0065] According to the present invention, the bonding strength of the bonding surface of wafers or substrates can be accurately inspected in a non-destructive manner by utilizing an optical image using infrared or short-wave infrared light, and the overall bonding strength distribution of the bonding surface (F) between wafers (W1)(W2) or substrates, as well as the presence and location of voids, bubbles, or foreign substances, can be accurately measured. Furthermore, since optical devices such as light-emitting devices or image detection devices (20) are relatively easy to develop and inexpensive, inspection costs can be significantly reduced. Additionally, because the wafers or substrates can be utilized as they are after inspection in a non-destructive manner, it is very economical, and the efficiency and productivity of inspection can be greatly increased as the image detection time and analysis time are short.

[0066] FIG. 2 is a conceptual side view illustrating a bonding strength inspection device (200) according to some other embodiments of the present invention.

[0067] As illustrated in FIG. 2, the image detection device (20) of the bonding force inspection device (200) according to some other embodiments of the present invention may be a reflective detection device (22) that detects light reflected by the bonding surface (F).

[0068] Accordingly, light generated from the light-emitting device (10) can be reflected by the bonding surface (F) and received by the image detection device (20), and the control unit (30) can determine the bonding strength of the bonding surface (F) using this reflected optical image.

[0069] Here, the image detection device (20) may be installed, for example, above the bonding surface (F), but is not necessarily limited thereto, and may be installed on the side of the bonding surface (F) as shown by the dotted line, or at various other locations.

[0070] Accordingly, according to the present invention, a light-emitting device (10) or an image detection device (20), etc., can be freely installed in various locations, either as a transmissive or reflective type, without being restricted by the space in which it is installed.

[0071] FIG. 3 is a conceptual side view illustrating a bonding strength inspection device (300) according to some other embodiments of the present invention.

[0072] As illustrated in FIG. 3, the image detection device (20) of the bonding force inspection device (300) according to some other embodiments of the present invention may be a partial image detection device (24) capable of capturing a partial image of the bonding surface (F) by a scan transfer device (M1) capable of moving along the bonding surface (F) or moving the bonding surface (F).

[0073] Therefore, by using a partial image detection device (24) of this scanning method, the resolution and precision of the optical image that can be partially acquired can be greatly improved, although the scanning transfer time is somewhat long.

[0074] FIG. 4 is a conceptual side view illustrating a bonding strength inspection device (400) according to some other embodiments of the present invention.

[0075] As illustrated in FIG. 4, the image detection device (20) of the bonding force inspection device (400) according to some other embodiments of the present invention may include a first camera (C1) installed at a first angle (A1) in a first direction (I) with respect to the vertically upward or vertically downward direction of the bonding surface (F).

[0076] Accordingly, the first angle (A1), which is the installation angle of the first camera (C1), can be fixedly set to the angle that has the best identification capability for voids, bubbles, foreign substances, etc., that may exist in various ways on the bonding surface (F) depending on the wafers (W1) (W2) or substrates in various materials and environments.

[0077] Therefore, the operator can set an optimal first angle (A1) according to various types and shapes of wafers or substrates to greatly improve the identification power and resolution of the optical image.

[0078] FIG. 5 is a conceptual side view illustrating a bonding strength inspection device (500) according to some other embodiments of the present invention.

[0079] As illustrated in FIG. 5, an image detection device (20) of a bonding force inspection device (500) according to some other embodiments of the present invention may include a first camera (C1) installed at a first angle (A1) in a first direction (I) with respect to the vertically upward or vertically downward direction of the bonding surface (F), and a second camera (C2) installed at a second angle (A2) different from the first angle (A1) in the first direction (I) with respect to the vertically upward or vertically downward direction of the bonding surface (F).

[0080] Accordingly, the first angle (A1) and the second angle (A2), which are the installation angles of the first camera (C1) and the second camera (C2), can be fixedly set to the angle that has the best identification capability for voids, bubbles, foreign substances, etc., which may exist in various ways on the bonding surface (F) depending on the wafers (W1)(W2) or substrates in various materials and environments.

[0081] Therefore, the operator can set the optimal first angle (A1) and second angle (A2) according to various types and shapes of wafers or substrates to further improve the identification power and resolution of optical images according to various angles.

[0082] FIG. 6 is a conceptual perspective view illustrating a bonding strength inspection device (600) according to some other embodiments of the present invention.

[0083] As illustrated in FIG. 6, the image detection device (20) of the bonding force inspection device (600) according to some other embodiments of the present invention may include a first camera (C1) installed at a first angle (A1) in a first direction (I) with respect to the vertically upward or vertically downward direction of the bonding surface (F), and a third camera (C3) installed at a third angle (A3) in a second direction (II) different from the first direction (I) with respect to the vertically upward or vertically downward direction of the bonding surface (F).

[0084] Accordingly, the first angle (A1) and the third angle (A3), which are the installation angles of the first camera (C1) and the third camera (C3), can be fixedly set to the angle that provides the best identification capability for voids, bubbles, foreign substances, etc., that may exist in various ways on the bonding surface (F) depending on the wafers (W1) (W2) or substrates in various materials and environments.

[0085] Here, for example, in order to increase the discernibility and resolution of the optical image at various angles, the first direction (I) may be the X-axis direction and the second direction (II) may be the Y-axis direction. However, this is not necessarily limited to this, and the first direction (I) and the second direction (II) may be applied in a wide variety of directions.

[0086] Therefore, the operator can set the optimal first angle (A1) and third angle (A3) according to various types and shapes of wafers or substrates, thereby further improving the identification power and resolution of optical images according to various angles regardless of patterns, etc.

[0087] FIG. 7 is a conceptual side view illustrating a bonding strength inspection device (700) according to some other embodiments of the present invention.

[0088] As illustrated in FIG. 7, the image detection device (20) of the bonding force inspection device (700) according to some other embodiments of the present invention may include a movable camera (C4) whose inspection angle is changed by an angle moving device (M2) that moves from a fourth angle (A4) to a fifth angle (A5) in a first direction (I) with respect to the vertically upward or vertically downward direction of the bonding surface (F).

[0089] Accordingly, by utilizing the continuous angle conversion function of the fourth camera (C4), it is possible to receive an optical image or a three-dimensional optical image with the best identification power for voids, bubbles, foreign substances, etc. that may exist in various ways on the bonding surface (F) depending on the wafers (W1) (W2) or substrates in various materials and environments.

[0090] Therefore, regardless of the various types and shapes of wafers or substrates, the identification power and resolution of two-dimensional or three-dimensional optical images according to the optimal angle can always be significantly improved.

[0091] FIG. 8 is a conceptual perspective view illustrating a bonding strength inspection device (800) according to some other embodiments of the present invention.

[0092] As illustrated in FIG. 8, a bonding force inspection device (800) according to some other embodiments of the present invention may further include a rotating device (M3) for rotating wafers (W1)(W2) or substrates bonded together so as to detect optical images at various angles.

[0093] Accordingly, by using a rotating device (M3) to rotate the wafers (W1)(W2) or substrates, optical images can be received from various angles using the first camera (C1) and the third camera (C3), and an optical image or a three-dimensional optical image with the best identification power for voids, bubbles, foreign substances, etc., that may exist on the bonding surface (F) depending on the wafers (W1)(W2) or substrates in various materials and environments can be received.

[0094] Therefore, regardless of the various types and shapes of wafers or substrates, the identification power and resolution of two-dimensional or three-dimensional optical images according to the optimal angle can always be significantly improved.

[0095] FIG. 9 is a flowchart illustrating a bonding strength inspection method according to some embodiments of the present invention.

[0096] As illustrated in FIGS. 1 to 9, a bonding strength inspection method according to some embodiments of the present invention may include: (a) a step of irradiating light toward a bonding surface (F) of wafers or substrates (W1) and (W2) bonded together; (b) a step of detecting an optical image of the bonding surface (F) with respect to the light; and (c) a step of determining the bonding state of the bonding surface (F) using a past database or a learned artificial intelligence model based on the optical image.

[0097] Here, infrared light or short-wave infrared light can be used so that the light can penetrate the wafer or substrate.

[0098] FIGS. 10 and FIGS. 11 are photographs showing examples of optical images of a bonding force inspection device (100) according to some embodiments of the present invention.

[0099] As illustrated in FIGS. 1 to 10, according to the present invention, an optical image in a visible light state, as in the left photograph of FIG. 10, cannot identify the bonding surface (F), but an optical image using infrared light or short-wave infrared light, as in the right photograph of FIG. 10, can identify the bonding force of the bonding surface (F) by brightness and darkness.

[0100] Next, as shown in FIG. 11, the bonding strength can be measured using the ratio of the total bright or total dark areas, the contrast ratio, or the pattern of the areas partially cut from the right photograph of FIG. 10.

[0101] However, the optical images obtainable in the bonding strength inspection device and method of the present invention are not limited to these two-dimensional optical images, and various optical images such as three-dimensional images, like three-dimensional ultrasound images, can all be applied.

[0102] The present invention has been described with reference to the embodiments illustrated in the drawings, but this is merely illustrative, and those skilled in the art will understand that various modifications and equivalent alternative embodiments are possible therefrom. Accordingly, the true technical scope of protection of the present invention should be determined by the technical spirit of the appended claims. Explanation of the symbols

[0103] W1, W2: Wafer F: Bonding surface 10: Light-emitting device 20: Image detection device 21: Through-beam detection device 22: Reflective detection device 23: Full image detection device 24: Partial image detection device M1: Scan transfer device I: First direction II: Second Direction III: The Third Direction C1: 1st camera A1: First angle C2: Second angle A2: The second angle C3: 3rd Camera A3: The third angle C4: Activated Camera A4: The 4th Angle A5: The 5th Angle M2: Angle movement device M3: Rotating device 30: Control unit S1: Brightness sensor S2: Frequency sensor S3: Thickness measurement sensor 100~800: Bonding strength inspection device

Claims

Claim 1 A bonding strength inspection device comprising: a light-emitting device that irradiates light toward a bonding surface of wafers or substrates bonded together; an image detection device that detects an optical image of the bonding surface in relation to the light generated by the light-emitting device; and a control unit that determines the bonding state of the bonding surface in a non-destructive manner based on the optical image applied from the image detection device; wherein the optical image is a two-dimensional planar image or a three-dimensional shape image that includes the entire area of ​​the bonding surface and is displayed as a difference in brightness of the image according to a difference in partial bonding strength of the bonding surface or the presence or absence of bubbles or foreign substances; and wherein the control unit determines the bonding strength or defects by determining the optical image based on a bonding strength database for each brightness that is pre-matched according to the reference brightness of the image. Claim 2 A bonding strength inspection device according to claim 1, wherein the light comprises infrared light or short-wave infrared light. Claim 3 delete Claim 4 delete Claim 5 delete Claim 6 A bonding strength inspection device according to claim 1, wherein the control unit includes an artificial intelligence model that learns training images using a deep learning method and determines bonding strength or defects by distinguishing the optical image. Claim 7 A bonding force inspection device according to claim 1, wherein the image sensing device is a transmission type sensing device that detects light transmitted through the bonding surface or a reflection type sensing device that detects light reflected by the bonding surface. Claim 8 A bonding force inspection device according to claim 1, wherein the image sensing device is installed above or below the bonding surface and is a full image sensing device capable of capturing an entire image of the bonding surface. Claim 9 A bonding force inspection device according to claim 1, wherein the image sensing device is a partial image sensing device capable of capturing a partial image of the bonding surface by means of a scan transfer device capable of moving along the bonding surface or moving the bonding surface. Claim 10 A bonding strength inspection device according to claim 1, wherein the control unit receives a brightness signal from a brightness sensor installed around the wafer or substrates or receives a brightness signal from the optical image, and applies a brightness control signal to the light-emitting device to adjust the brightness of the light so as to improve the identification power of the optical image. Claim 11 A bonding strength inspection device according to claim 1, wherein the control unit receives a frequency signal from a frequency sensor installed around the wafer or substrates or receives a frequency signal from the optical image, and applies a frequency control signal that converts the frequency of light to the light-emitting device so as to improve the identification power of the optical image. Claim 12 A bonding strength inspection device according to claim 1, wherein the control unit receives a thickness signal from a thickness measuring sensor installed around the wafer or substrates or receives a thickness signal from the optical image, and applies a thickness corresponding control signal to the light-emitting device to convert the brightness or frequency of light so as to improve the identification power of the optical image. Claim 13 In claim 1, the image detection device is a bonding force inspection device installed vertically upward or vertically downward with respect to the bonding surface. Claim 14 A bonding force inspection device according to claim 1, wherein the image sensing device comprises a first camera installed at a first angle in a first direction with respect to the vertically upward or vertically downward direction of the bonding surface. Claim 15 A bonding force inspection device according to claim 14, wherein the image sensing device comprises a second camera installed at a second angle different from the first angle of the first direction with respect to the vertically upward or vertically downward direction of the bonding surface. Claim 16 A bonding force inspection device according to claim 14, wherein the image sensing device further comprises a third camera installed at a third angle in a second direction different from the first direction with respect to the vertically upward or vertically downward direction of the bonding surface. Claim 17 A bonding force inspection device according to claim 1, wherein the image sensing device comprises a movable camera whose inspection angle is changed by an angle moving device that moves from a fourth angle to a fifth angle in a first direction relative to the vertically upward or vertically downward direction of the bonding surface. Claim 18 A bonding force inspection device according to claim 1, further comprising a rotating device for rotating the wafers or substrates bonded together so as to detect the optical image at various angles. Claim 19 A bonding strength inspection method comprising: (a) a step of irradiating light toward the bonding surface of wafers or substrates bonded together; (b) a step of detecting an optical image of the bonding surface with respect to the light; and (c) a step of determining the bonding state of the bonding surface in a non-destructive manner using a past database or a learned artificial intelligence model based on the optical image. Claim 20 A light-emitting device that irradiates light toward the bonding surface of wafers or substrates bonded together; an image-sensing device that detects an optical image of the bonding surface with respect to the light generated by the light-emitting device; A bonding strength inspection device comprising: a control unit that determines the bonding state of the bonding surface in a non-destructive manner based on the optical image applied from the image detection device; wherein the light includes infrared light or short-wave infrared light, and the optical image is a two-dimensional planar image that includes the entire area of ​​the bonding surface and is displayed as a difference in brightness of the image according to a difference in partial bonding strength of the bonding surface or the presence or absence of bubbles or foreign substances, or a three-dimensional shape image that includes the entire area of ​​the bonding surface and is displayed three-dimensionally according to a difference in partial surface shape of the bonding surface or the shape of bubbles or foreign substances, and the control unit determines the bonding strength or defects by determining the optical image based on a bonding strength database pre-matched according to the reference brightness of the image, or includes an artificial intelligence model that learns training images in a deep learning manner and determines the bonding strength or defects by determining the optical image.

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