Apparatus and method for wafer bonding alignment detection

Abstract

The present application relates to an apparatus and a method for wafer bonding alignment detection. The apparatus includes an imaging portion and a light source portion. The imaging portion includes an imaging assembly, a first fine adjustment stage to adjust an included angle of the imaging assembly with an x-axis, and a second fine adjustment stage to adjust an included angle of the imaging assembly with a y-axis. The light source portion is oppositely arranged with the imaging portion in a z-axis direction and includes a light source assembly, a third fine adjustment stage to adjust an included angle of the light source assembly with the x-axis, and a fourth fine adjustment stage to adjust an included angle of the light source assembly with the y-axis. Any two of the x-axis, the y-axis, and the z-axis are perpendicular to each other. The light source assembly is configured to illuminate a wafer disposed between the imaging assembly and the light source assembly, and the imaging assembly is configured to microscopically image the wafer to obtain an image. At least one of the imaging portion and the light source portion further includes a fifth fine adjustment stage to adjust a displacement of at least one of the imaging assembly and the light source assembly in the z-axis direction.

Description

Technical Field

[0001] This application generally relates to the field of semiconductor equipment, and more specifically, to apparatus and methods for wafer bonding alignment inspection. Background Technology

[0002] In semiconductor equipment manufacturing processes, after wafer bonding is completed, the alignment accuracy of the wafer bonding needs to be checked. The common practice is to perform microscopic imaging of the markings on the two bonded wafers and then calculate the deviation between the markings on the two wafers. During the imaging process, multiple reflections of light on the surfaces and within the wafers can cause interference with the image. This interference reduces image contrast, affects the clarity of the detected image, and consequently affects the detection accuracy.

[0003] The degree of interference caused by the aforementioned multilayer reflections to the image is related to the positional relationship between the illumination device and the light-collecting device (also known as the imaging device). However, existing wafer bonding alignment inspection devices do not specifically consider the positional relationship between the illumination device and the light-collecting device, or how to achieve such a relationship, in order to obtain a clear identification image for accurate inspection. Summary of the Invention

[0004] This application proposes a device for wafer bonding alignment inspection, which can achieve collimation adjustment between the illumination device and the light collection device through simple operation and has high repeatability.

[0005] In one aspect, this application provides an apparatus for wafer bonding alignment inspection, comprising an imaging unit and a light source unit. The imaging unit includes: an imaging component; a first fine-tuning slide for adjusting the angle between the imaging component and the x-axis; and a second fine-tuning slide for adjusting the angle between the imaging component and the y-axis. The light source unit is disposed opposite to the imaging unit in the z-axis direction and includes: a light source component; a third fine-tuning slide for adjusting the angle between the light source component and the x-axis; and a fourth fine-tuning slide for adjusting the angle between the light source component and the y-axis. Any two of the x-axis, y-axis, and z-axis are perpendicular to each other. The light source component is configured to illuminate a wafer disposed between the imaging component and the light source component. The imaging component is configured to perform microscopic imaging of the wafer to obtain an image. At least one of the imaging unit and the light source unit further includes a fifth fine-tuning slide for adjusting the displacement of at least one of the imaging component and the light source component in the z-axis direction.

[0006] In some embodiments, the apparatus further includes a linear motion system for driving at least one of the imaging unit and the light source unit to move in the x-axis and / or y-axis directions.

[0007] In some embodiments, the imaging unit further includes a first angle slide transition plate, the first angle slide transition plate including a first mounting plate and a second mounting plate that are perpendicular to each other, the first fine-tuning slide is mounted on the first mounting plate, and the second fine-tuning slide is mounted on the second mounting plate.

[0008] In some embodiments, the imaging component is mounted on one of the first fine-tuning slide and the second fine-tuning slide.

[0009] In some embodiments, the fifth fine-tuning slide is connected to the other of the first fine-tuning slide and the second fine-tuning slide.

[0010] In some embodiments, the light source unit further includes a second angle slide transition plate, the second angle slide transition plate including a third mounting plate and a fourth mounting plate that are perpendicular to each other, the third fine-tuning slide is mounted on the third mounting plate, and the fourth fine-tuning slide is mounted on the fourth mounting plate.

[0011] In some embodiments, the light source assembly is mounted on one of the third and fourth fine-tuning slides.

[0012] In some embodiments, the fifth fine-tuning slide is connected to the other of the third and fourth fine-tuning slides.

[0013] In some embodiments, the first fine-tuning slide includes a first adjusting handle and a first adjusting plane, the first adjusting plane being configured to rotate accordingly about an axis parallel to the axis of the first adjusting handle as the first adjusting handle rotates; the second fine-tuning slide includes a second adjusting handle and a second adjusting plane, the second adjusting plane being configured to rotate accordingly about an axis parallel to the axis of the second adjusting handle as the second adjusting handle rotates; the third fine-tuning slide includes a third adjusting handle and a third adjusting plane, the third adjusting plane being configured to rotate accordingly about an axis parallel to the axis of the third adjusting handle as the third adjusting handle rotates; and the fourth fine-tuning slide includes a fourth adjusting handle and a fourth adjusting plane, the fourth adjusting plane being configured to rotate accordingly about an axis parallel to the axis of the fourth adjusting handle as the fourth adjusting handle rotates.

[0014] In some embodiments, the first fine-tuning slide further includes a first locking knob, which prevents the first adjusting handle from rotating when the first locking knob is tightened; the second fine-tuning slide further includes a second locking knob, which prevents the second adjusting handle from rotating when the second locking knob is tightened; the third fine-tuning slide further includes a third locking knob, which prevents the third adjusting handle from rotating when the third locking knob is tightened; and the fourth fine-tuning slide further includes a fourth locking knob, which prevents the fourth adjusting handle from rotating when the fourth locking knob is tightened.

[0015] In some embodiments, the fifth fine-tuning slide includes an adjustment handle and an adjustment plate, the adjustment plate being configured to move accordingly along the axial direction of the adjustment handle as the adjustment handle is rotated.

[0016] In some embodiments, the fifth fine-tuning slide further includes a locking knob, which prevents the adjustment handle from rotating when the locking knob is tightened.

[0017] In some embodiments, the apparatus further includes an image processing device connected to the imaging component, the image processing device being configured to receive the image from the imaging component and process the image.

[0018] In some embodiments, the apparatus further includes a display device connected to at least one of the imaging component and the image processing device.

[0019] In another aspect, this application provides a method for performing wafer bonding alignment inspection using an apparatus for wafer bonding alignment inspection according to any embodiment of this application, comprising: placing a reference wafer having a reference mark between an imaging component and a light source component; aligning the imaging component and the light source component with the reference mark; adjusting the positional relationship between the imaging component and the light source component; during the adjustment of the positional relationship between the imaging component and the light source component, performing microscopic imaging of the reference mark through the imaging component to obtain a series of reference images, each reference image corresponding to a positional relationship; and transmitting the series of reference images one by one in real time to an image processing device. The system calculates the contrast of the series of reference images; determines the optimal positional relationship corresponding to the best contrast among the series of reference images; locks the imaging component and the light source component in the optimal positional relationship; places the wafer to be tested between the imaging component and the light source component, the wafer to be tested including a first wafer and a second wafer bonded together, the first wafer having a first identifier and the second wafer having a second identifier; aligns the imaging component and the light source component with the first identifier and the second identifier; and performs microscopic imaging of the first identifier and the second identifier through the imaging component to obtain an aligned image of the wafer to be tested.

[0020] In some embodiments, aligning the imaging assembly and the light source assembly with the reference mark includes driving at least one of the imaging unit and the light source unit via a linear motion system.

[0021] In some embodiments, the positional relationship between the imaging component and the light source component is adjusted by at least one of the following steps: adjusting the angle between the imaging component and the x-axis using the first fine-tuning slide; adjusting the angle between the imaging component and the y-axis using the second fine-tuning slide; adjusting the angle between the light source component and the x-axis using the third fine-tuning slide; adjusting the angle between the light source component and the y-axis using the fourth fine-tuning slide; or adjusting the displacement of at least one of the imaging component and the light source component in the z-axis direction using the fifth fine-tuning slide.

[0022] In some embodiments, the angle between the imaging component and the x-axis is adjusted by rotating the first adjustment handle of the first fine-tuning slide, the angle between the imaging component and the y-axis is adjusted by rotating the second adjustment handle of the second fine-tuning slide, the angle between the light source component and the x-axis is adjusted by rotating the third adjustment handle of the third fine-tuning slide, the angle between the light source component and the y-axis is adjusted by rotating the fourth adjustment handle of the fourth fine-tuning slide, and the displacement of at least one of the imaging component and the light source component in the z-axis direction is adjusted by rotating the fifth adjustment handle of the fifth fine-tuning slide.

[0023] In some embodiments, locking the imaging component and the light source component in the optimal positional relationship includes, after adjusting the imaging component and the light source component to the optimal positional relationship: tightening the locking knob of the first fine-tuning slide to prevent the first adjustment handle from rotating; tightening the locking knob of the second fine-tuning slide to prevent the second adjustment handle from rotating; tightening the locking knob of the third fine-tuning slide to prevent the third adjustment handle from rotating; tightening the locking knob of the fourth fine-tuning slide to prevent the fourth adjustment handle from rotating; and tightening the locking knob of the fifth fine-tuning slide to prevent the fifth adjustment handle from rotating.

[0024] In some embodiments, aligning the imaging assembly and the light source assembly with the first and second identifiers includes driving the imaging unit and the light source unit to move synchronously via a linear motion system.

[0025] In some embodiments, the repetition further includes: removing the wafer to be tested; and, while the imaging component and the light source component maintain the optimal positional relationship, placing another wafer to be tested between the imaging component and the light source component for wafer bonding alignment testing.

[0026] Details of one or more embodiments of this application are set forth in the following figures and description. Other features, objectives, and advantages will become apparent from the description, figures, and claims. Attached Figure Description

[0027] The following figures are mentioned and included in the disclosure in this specification:

[0028] Figure 1 This is a schematic diagram showing three possible positional relationships between an illumination device and a light-collecting device used for wafer bonding alignment inspection.

[0029] Figure 2 To have in lighting devices and light collection devices Figure 1 A schematic diagram of the images of the markings on the wafer obtained under various positional relationships shown.

[0030] Figure 3 This is a perspective view of an apparatus for wafer bonding alignment inspection according to some embodiments of this application.

[0031] Figure 3A for Figure 3 The diagram shows a top view of the apparatus used for wafer bonding alignment inspection.

[0032] Figure 3B for Figure 3 The image shows a bottom view of the apparatus used for wafer bonding alignment inspection.

[0033] Figure 4 In order to be in Figure 3 The diagram shows a perspective view of a fine-tuning slide used in an apparatus for wafer bonding alignment inspection.

[0034] Figure 5 In order to be in Figure 3 The diagram shows a perspective view of another fine-tuning slide used in the apparatus for wafer bonding alignment inspection.

[0035] By convention, the various features illustrated in the figures may not be drawn to scale. Therefore, for clarity, the dimensions of various features may be arbitrarily enlarged or reduced. The shapes of the components illustrated are merely exemplary and do not limit the actual shapes of the components. Furthermore, for clarity, the embodiments illustrated may be simplified. Therefore, the figures may not depict all components of a given device or apparatus. Finally, the same reference numerals may be used throughout the specification and figures to denote the same features. Detailed Implementation

[0036] To better understand the spirit of this application, the following description, in conjunction with some embodiments of this application, will provide further details.

[0037] The terms "in one embodiment" or "according to one embodiment" used in this specification do not necessarily refer to the same specific embodiment, and the terms "in other (some / some) embodiments" or "according to other (some / some) embodiments" used in this specification do not necessarily refer to different specific embodiments. The purpose is to, for example, include combinations of all or some of the exemplary embodiments. The meaning of "upper" and "lower" as used herein is not limited to the relationship directly presented in the drawings, but should include descriptions with explicit corresponding relationships, such as "left" and "right," or the opposite of "upper" and "lower." The term "connection" as used herein should be understood to encompass both "direct connection" and "connection via one or more intermediate components." The names of various components used in this specification are for illustrative purposes only and are not intended to be limiting; different manufacturers may use different names to refer to components with the same function.

[0038] Various embodiments of this application are discussed in detail below. Although specific embodiments are discussed, it should be understood that these embodiments are for illustrative purposes only. Those skilled in the art will recognize that other components and configurations can be used without departing from the spirit and scope of this application. Implementations of this application need not include all components or steps in the embodiments described in the specification, and the execution order of the steps can be adjusted according to the actual application.

[0039] Figure 1 Three positional relationships between the illumination device 2 and the light collecting device 1 used for wafer bonding alignment inspection are shown: misalignment relationship 3 (their optical axes are offset), deflection relationship 4 (their optical axes are not parallel), and coaxial relationship 5 (they are optically collimated). Due to interference caused by multi-layer reflections of light on and within the wafer surface, the image sharpness obtained under different positional relationships will vary. The distance between the illumination device 2 and the light collecting device 1 also has a certain impact on image sharpness.

[0040] Figure 2 It shows that the lighting device and the light collecting device have Figure 1 Images of cross-shaped markings on a wafer obtained under various positional relationships are shown, wherein image 6 is obtained when the two are misaligned (3), image 7 is obtained when the two are deflected (4), and image 8 is obtained when the two are coaxial (5).

[0041] like Figure 2 As shown, compared to image 8 obtained under coaxial relationship 5, image 6 obtained under misalignment relationship 3 and image 7 obtained under deflection relationship 4 have lower contrast, resulting in less clear marker boundaries. Such blurry marker boundaries can affect the detection of marker alignment accuracy, for example, reducing the accuracy of marker deviation calculation.

[0042] In contrast, aligning the illumination device and the light-collecting device coaxially allows for relatively clear images in various wafer bonding inspections. However, this requires ensuring a very high degree of collimation between these devices. Existing wafer bonding alignment inspection devices generally do not specifically consider optimizing the positional relationship between the illumination device and the light-collecting device, thus making collimation adjustment impossible or requiring complex mechanical adjustments to achieve the required collimation.

[0043] This application proposes an improved device for wafer bonding alignment inspection, which allows for collimation adjustment between the illumination device and the light collection device through simple operation, thereby improving inspection accuracy.

[0044] Figure 3A perspective view of an apparatus for wafer bonding alignment inspection according to some embodiments of this application is shown. For simplification purposes, Figure 3 Not all components of the device are shown, but those skilled in the art should understand the possible structures and configurations of the other unshown components of the device.

[0045] like Figure 3 As shown, the device generally includes an imaging unit 1 and a light source unit 2 disposed opposite to each other. The imaging unit 1 includes an imaging assembly 14, a first fine-tuning slide 11, and a second fine-tuning slide 12. The imaging assembly 14 may include a camera, a lens, etc. The light source unit 2 includes a light source assembly 25, a third fine-tuning slide 22, a fourth fine-tuning slide 23, and a fifth fine-tuning slide 21. The light source assembly 25 may include a light source, a lens, etc. A wafer can be placed between the imaging assembly 14 and the light source assembly 25, for example, a chuck containing the wafer can be inserted between the imaging assembly 14 and the light source assembly 25. The light source assembly 25 is configured to emit illumination light to illuminate the wafer placed between the imaging assembly 14 and the light source assembly 25. The imaging assembly 14 is configured to perform microscopic imaging of the wafer. In some embodiments, the imaging assembly 14 may be connected to an image processing device and transmit the acquired image to the image processing device for related processing. The imaging assembly 14 and / or the image processing device may also be connected to a display device. The display device can be configured to display images and / or processed images and / or data acquired by the imaging component 14.

[0046] exist Figure 3In the xyz coordinate system shown (where any two of the x-axis, y-axis and z-axis are perpendicular to each other), the positional relationship between the imaging component 14 and the light source component 25 can be adjusted in at least five dimensions: x (i.e., displacement in the x-axis direction), y (i.e., displacement in the y-axis direction), z (i.e., displacement in the z-axis direction), θx (i.e., the angle with the x-axis), and θy (i.e., the angle with the y-axis). The first fine-tuning slide 11 can be used to adjust the angle between the imaging component 14 and the x-axis (i.e., the angle between the optical axis of the imaging component 14 and the x-axis); the second fine-tuning slide 12 can be used to adjust the angle between the imaging component 14 and the y-axis (i.e., the angle between the optical axis of the imaging component 14 and the y-axis); the third fine-tuning slide 22 can be used to adjust the angle between the light source component 25 and the x-axis (i.e., the angle between the optical axis of the light source component 25 and the x-axis); the fourth fine-tuning slide 23 can be used to adjust the angle between the light source component 25 and the y-axis (i.e., the angle between the optical axis of the light source component 25 and the y-axis); and the fifth fine-tuning slide 21 can be used to adjust the displacement of the light source component 25 in the z-axis direction. In some embodiments, the imaging unit 1 includes a fine-tuning slide for adjusting the displacement of the imaging component 14 in the z-axis direction, while the light source unit 2 does not include the fifth fine-tuning slide 21; or, both the imaging unit 1 and the light source unit 2 include fine-tuning slides for adjusting the displacement of the respective components in the z-axis direction. Alternatively, the imaging unit 1 and / or the light source unit 2 can be moved in the x-axis and / or y-axis directions by a linear motion system (not shown in the figure), thereby causing the imaging component 14 and / or the light source component 25 to move in the x-axis and / or y-axis directions. The linear motion system may include a motor and a transmission mechanism. Those skilled in the art should be familiar with the structural design and operation methods of various linear motion systems, which will not be described in detail here. In some embodiments, the imaging unit 1 and the light source unit 2 may each have a corresponding linear motion system. In other embodiments, only one of the imaging unit 1 and the light source unit 2 has a linear motion system. In some embodiments, the imaging unit 1 and the light source unit 2 can move synchronously in the x-axis and / or y-axis directions under the drive of the linear motion system, and the relative positions of the imaging component 14 and the light source component 25 remain unchanged during the movement.

[0047] Figure 4 A perspective view of the fifth fine-tuning slide 21 is shown. Figure 4 As shown, the fifth fine-tuning slide 21 has an adjusting handle 201 and a locking knob 202. When the adjusting handle 201 is rotated, the adjusting plate 205 of the fifth fine-tuning slide 21 can move accordingly along the axial direction of the adjusting handle 201. Figure 3 In the device shown, the displacement of the light source assembly 25 in the z-axis direction can be adjusted by rotating the adjustment handle 201 of the fifth fine-tuning slide 21. After tightening the locking knob 202 of the fifth fine-tuning slide 21, the adjustment handle 201 will be unable to rotate, thereby fixing the position of the light source assembly 25 in the z-axis direction. Figure 4The structure of the fifth fine-tuning slide 21 shown is merely exemplary, and other adjustment devices that can achieve similar functions can also be used to implement the fifth fine-tuning slide 21.

[0048] The first fine-tuning slide 11, the second fine-tuning slide 12, the third fine-tuning slide 22, and the fourth fine-tuning slide 23 can be angle fine-tuning slides with similar structures. Figure 5 A three-dimensional view of this angle-adjusting slide is shown. (See diagram below.) Figure 5 As shown, this angle fine-tuning slide has an adjustment handle 203 and a locking knob 204. When the adjustment handle 203 is rotated, the adjustment plane 206 of the angle fine-tuning slide can rotate accordingly about an axis parallel to the axis of the adjustment handle 203. Figure 3 In the illustrated device, the angle between the imaging component 14 and the x-axis can be adjusted by rotating the adjustment handle 203 of the first fine-tuning slide 11; the angle between the imaging component 14 and the y-axis can be adjusted by rotating the adjustment handle 203 of the second fine-tuning slide 12; the angle between the light source component 25 and the x-axis can be adjusted by rotating the adjustment handle 203 of the third fine-tuning slide 22; and the angle between the light source component 25 and the y-axis can be adjusted by rotating the adjustment handle 203 of the fourth fine-tuning slide 23. After tightening the locking knob 204 of the first fine-tuning slide 11, the adjustment handle 203 of the first fine-tuning slide 11 will be unable to rotate, thus fixing the angle between the imaging component 14 and the x-axis. Similarly, after tightening the locking knob 204 of the second fine-tuning slide 12, the adjustment handle 203 of the second fine-tuning slide 12 will be unable to rotate, thus fixing the angle between the imaging component 14 and the y-axis. After tightening the locking knob 204 of the third fine-tuning slide 22, the adjusting handle 203 of the third fine-tuning slide 22 will be unable to rotate, thereby fixing the angle between the light source assembly 25 and the x-axis. After tightening the locking knob 204 of the fourth fine-tuning slide 23, the adjusting handle 203 of the fourth fine-tuning slide 23 will be unable to rotate, thereby fixing the angle between the light source assembly 25 and the y-axis. Figure 5 The structure of the angle fine-tuning slide shown is merely exemplary; other adjustment devices that can achieve similar functions can also be used to implement the first fine-tuning slide 11, the second fine-tuning slide 12, the third fine-tuning slide 22, and the fourth fine-tuning slide 23.

[0049] Figure 3A for Figure 3 A top view of the device shown. Figure 3A As shown, the first fine-tuning slide 11 and the second fine-tuning slide 12 are mounted on the first angle slide transition plate 13. The first angle slide transition plate 13 includes two mutually perpendicular mounting plates, which are mounted on... Figure 3AThe cross-section shown generally forms an L-shape. The first fine-tuning slide 11 and the second fine-tuning slide 12 are respectively connected to the two mounting plates, so that the adjustment planes 206 of the first fine-tuning slide 11 and the second fine-tuning slide 12 are perpendicular to each other, allowing for angular adjustment relative to the x-axis and y-axis, respectively. The imaging assembly 14 is mounted on the first fine-tuning slide 11. In other embodiments, the imaging assembly 14, the first fine-tuning slide 11, and the second fine-tuning slide 12 may have different mounting positions than those shown in the figure, while still achieving similar functions without departing from the spirit or scope of this application.

[0050] Figure 3B for Figure 3 A bottom view of the device shown. (e.g.) Figure 3B As shown, the third fine-tuning slide 22 and the fourth fine-tuning slide 23 are mounted on the second angle slide transition plate 24. The second angle slide transition plate 24 includes two mutually perpendicular mounting plates, which are mounted on... Figure 3B The cross-section shown generally forms an L-shape. The third and fourth fine-tuning slides 22 and 23 are respectively connected to the two mounting plates, thus their adjustment planes 206 are perpendicular to each other, allowing for angular adjustment relative to the x-axis and y-axis, respectively. The light source assembly 25 is mounted on the third fine-tuning slide 22. The fifth fine-tuning slide 21 is connected to the fourth fine-tuning slide 23. In other embodiments, the light source assembly 25, the third fine-tuning slide 22, the fourth fine-tuning slide 23, and the fifth fine-tuning slide 21 may have different mounting positions than those shown in the figure, while still achieving similar functions without departing from the spirit or scope of this application.

[0051] Figure 3 The apparatus shown can adjust the imaging assembly 14 and the light source assembly 25 to achieve optimal collimation via the first fine-tuning slide 11, the second fine-tuning slide 12, the third fine-tuning slide 22, the fourth fine-tuning slide 23, and the fifth fine-tuning slide 21. By using this apparatus with optimal collimation to perform microscopic imaging of the markings on the wafer under inspection, images with extremely high clarity can be obtained, which helps in subsequent calculations of marking deviation and alignment accuracy based on these images.

[0052] According to embodiments of this application, wafer bonding alignment detection can be performed using the following method. Although the following is in conjunction with... Figure 3 The apparatus shown is used to describe the method, and it should be understood that the method can also be applied to other apparatuses with similar structures and / or functions.

[0053] First, a reference wafer with a reference mark is placed between the imaging assembly 14 and the light source assembly 25. At least one of the imaging unit 1 and the light source unit 2 is moved (including moving in the x-axis and / or y-axis directions) by a linear motion system until the imaging assembly 14 and the light source assembly 25 are aligned with the reference mark on the reference wafer. In some embodiments, the field of view of the imaging assembly 14 can be displayed by a display device connected to the imaging assembly 14 to observe whether the imaging assembly 14 and the light source assembly 25 are aligned with the reference mark on the reference wafer. For example, when the image of the reference mark is approximately located at the center of the field of view of the imaging assembly 14, the imaging assembly 14 is considered to be aligned with the reference mark; when the brightness of the image of the reference mark reaches its maximum value or exceeds a predetermined threshold, the light source assembly 25 is considered to be aligned with the reference mark.

[0054] Next, the positional relationship between the imaging component 14 and the light source component 25 is adjusted by at least one of the following steps: rotating the adjustment handle 203 of the first fine-tuning slide 11 to adjust the angle between the imaging component 14 and the x-axis; rotating the adjustment handle 203 of the second fine-tuning slide 12 to adjust the angle between the imaging component 14 and the y-axis; rotating the adjustment handle 203 of the third fine-tuning slide 22 to adjust the angle between the light source component 25 and the x-axis; rotating the adjustment handle 203 of the fourth fine-tuning slide 23 to adjust the angle between the light source component 25 and the y-axis; and rotating the adjustment handle 201 of the fifth fine-tuning slide 21 to adjust the displacement of the light source component 25 in the z-axis direction. These steps can be repeated multiple times in any order or combination.

[0055] During the adjustment process, the imaging component 14 can perform microscopic imaging on the reference marker to obtain a series of reference images, each corresponding to a positional relationship. The imaging component 14 can transmit the obtained series of reference images one by one in real time to an image processing device connected to the imaging component 14 to calculate the contrast of these reference images. In some embodiments, at least one of the reference images and / or the calculated contrast can be displayed by a display device. Based on the calculated contrast, an optimal reference image corresponding to the best contrast and an optimal positional relationship corresponding to the optimal reference image can be determined.

[0056] Then, the imaging assembly 14 and the light source assembly 25 are locked in the optimal positional relationship. For example, after adjusting the imaging assembly 14 and the light source assembly 25 to the optimal positional relationship, the angle between the imaging assembly 14 and the x-axis is fixed by tightening the locking knob 204 of the first fine-tuning slide 11, the angle between the imaging assembly 14 and the y-axis is fixed by tightening the locking knob 204 of the second fine-tuning slide 12, the angle between the light source assembly 25 and the x-axis is fixed by tightening the locking knob 204 of the third fine-tuning slide 22, the angle between the light source assembly 25 and the y-axis is fixed by tightening the locking knob 204 of the fourth fine-tuning slide 23, and the position of the light source assembly 25 in the z-axis direction is fixed by tightening the locking knob 202 of the fifth fine-tuning slide 21.

[0057] After the above steps, the imaging component 14 and the light source component 25 have achieved optimal collimation. Next, the imaging component 14 and the light source component 25 with the above-mentioned optimal collimation can be used to perform wafer bonding alignment detection.

[0058] The wafer to be inspected is placed between the imaging assembly 14 and the light source assembly 25. The wafer to be inspected includes a first wafer and a second wafer bonded together. The first wafer has a first identifier, and the second wafer has a second identifier. The first identifier and the second identifier typically at least partially overlap. Generally, if the first identifier and the second identifier completely overlap, the first wafer and the second wafer are considered to be perfectly aligned.

[0059] The imaging unit 1 and the light source unit 2 are driven to move synchronously by a linear motion system until the imaging assembly 14 and the light source assembly 25 are aligned with the first and second marks on the wafer to be inspected. In some embodiments, the field of view of the imaging assembly 14 can be displayed by a display device connected to the imaging assembly 14, thereby observing whether the imaging assembly 14 and the light source assembly 25 are aligned with the first and second marks on the wafer to be inspected. For example, when the images of the first and second marks are approximately located at the center of the field of view of the imaging assembly 14, it can be considered that the imaging assembly 14 and the light source assembly 25 are aligned with the first and second marks.

[0060] Imaging assembly 14 is used to perform microscopic imaging on the first and second markings to obtain an alignment image of the wafer under test. The imaging assembly 14 can transmit the obtained alignment image to an image processing device connected to the imaging assembly 14 to calculate the deviation between the first and second markings, thereby obtaining the alignment accuracy of the wafer under test.

[0061] After locking the imaging component 14 and the light source component 25 in the optimal positional relationship, multiple wafers to be inspected can be inspected continuously without readjusting the position and angle of the imaging component 14 and the light source component 25.

[0062] The above method can obtain the alignment image of the wafer under the best collimation through simple and convenient operation. The obtained alignment image has high clarity, which is beneficial to improving the detection accuracy.

[0063] The description in this specification is provided to enable those skilled in the art to make or use this application. Various modifications to this application will readily be apparent to those skilled in the art, and the general principles defined in this specification can be applied to other variations without departing from the spirit or scope of this application. Therefore, this application is not limited to the examples and designs described in this specification, but is given the widest scope consistent with the principles and novel features disclosed in this specification.

Claims

1. An apparatus for wafer bonding alignment inspection, comprising: Imaging unit, comprising: Imaging components; A first fine-tuning slide is used to adjust the angle between the imaging component and the x-axis; and A second fine-tuning slide is used to adjust the angle between the imaging component and the y-axis; and A light source unit, which is disposed opposite to the imaging unit in the z-axis direction and includes: Light source components; A third fine-tuning slide is used to adjust the angle between the light source assembly and the x-axis; and The fourth fine-tuning slide is used to adjust the angle between the light source assembly and the y-axis; Wherein, any two of the x-axis, y-axis, and z-axis are perpendicular to each other. The light source assembly is configured to illuminate the wafer disposed between the imaging assembly and the light source assembly. The imaging assembly is configured to perform microscopic imaging on the wafer to obtain an image. At least one of the imaging unit and the light source unit further includes a fifth fine-tuning slide, which is used to adjust the displacement of at least one of the imaging unit and the light source assembly in the z-axis direction. The first fine-tuning slide, the second fine-tuning slide, the third fine-tuning slide, the fourth fine-tuning slide, and the fifth fine-tuning slide cooperate with each other to achieve an optimal positional relationship between the imaging unit and the light source unit so that the image acquired by the imaging unit achieves the best contrast.

2. The apparatus of claim 1, further comprising a linear motion system for driving at least one of the imaging unit and the light source unit to move in the x-axis and / or y-axis directions.

3. The apparatus according to claim 1, wherein the imaging unit further includes a first angle slide transition plate, the first angle slide transition plate including a first mounting plate and a second mounting plate perpendicular to each other, the first fine-tuning slide being mounted on the first mounting plate, and the second fine-tuning slide being mounted on the second mounting plate.

4. The apparatus of claim 3, wherein the imaging component is mounted on one of the first fine-tuning slide and the second fine-tuning slide.

5. The apparatus of claim 4, wherein the fifth fine-tuning slide is connected to the other of the first fine-tuning slide and the second fine-tuning slide.

6. The apparatus according to claim 1, wherein the light source unit further includes a second angle slide transition plate, the second angle slide transition plate including a third mounting plate and a fourth mounting plate perpendicular to each other, the third fine-tuning slide being mounted on the third mounting plate, and the fourth fine-tuning slide being mounted on the fourth mounting plate.

7. The apparatus of claim 6, wherein the light source assembly is mounted on one of the third fine-tuning slide and the fourth fine-tuning slide.

8. The apparatus of claim 7, wherein the fifth fine-tuning slide is connected to the other of the third and fourth fine-tuning slides.

9. The apparatus of claim 1, wherein the first fine-tuning slide includes a first adjusting handle and a first adjusting plane, the first adjusting plane being configured to rotate accordingly about an axis parallel to the axis of the first adjusting handle as the first adjusting handle rotates; the second fine-tuning slide includes a second adjusting handle and a second adjusting plane, the second adjusting plane being configured to rotate accordingly about an axis parallel to the axis of the second adjusting handle as the second adjusting handle rotates; the third fine-tuning slide includes a third adjusting handle and a third adjusting plane, the third adjusting plane being configured to rotate accordingly about an axis parallel to the axis of the third adjusting handle as the third adjusting handle rotates; and the fourth fine-tuning slide includes a fourth adjusting handle and a fourth adjusting plane, the fourth adjusting plane being configured to rotate accordingly about an axis parallel to the axis of the fourth adjusting handle as the fourth adjusting handle rotates.

10. The apparatus of claim 9, wherein the first fine-tuning slide further includes a first locking knob, wherein when the first locking knob is tightened, the first adjusting handle cannot be rotated; the second fine-tuning slide further includes a second locking knob, wherein when the second locking knob is tightened, the second adjusting handle cannot be rotated; the third fine-tuning slide further includes a third locking knob, wherein when the third locking knob is tightened, the third adjusting handle cannot be rotated; and the fourth fine-tuning slide further includes a fourth locking knob, wherein when the fourth locking knob is tightened, the fourth adjusting handle cannot be rotated.

11. The apparatus of claim 1, wherein the fifth fine-tuning slide comprises an adjustment handle and an adjustment plate, the adjustment plate being configured to move accordingly along the axial direction of the adjustment handle as the adjustment handle is rotated.

12. The apparatus of claim 11, wherein the fifth fine-tuning slide further includes a locking knob, wherein the adjusting handle cannot be rotated when the locking knob is tightened.

13. The apparatus of claim 1, further comprising an image processing device connected to the imaging component, the image processing device being configured to receive the image from the imaging component and process the image.

14. The apparatus of claim 13, further comprising a display device connected to at least one of the imaging component and the image processing device.

15. A method for wafer bonding alignment inspection using the apparatus according to claim 1, comprising: A reference wafer with a reference mark is placed between the imaging assembly and the light source assembly; Align the imaging assembly and the light source assembly with the reference mark; The positional relationship between the imaging component and the light source component is adjusted by the cooperation of the first fine-tuning slide, the second fine-tuning slide, the third fine-tuning slide, the fourth fine-tuning slide and the fifth fine-tuning slide. During the process of adjusting the positional relationship between the imaging component and the light source component, the imaging component performs microscopic imaging on the reference mark to obtain a series of reference images, each reference image corresponding to a positional relationship. The series of reference images are transmitted one by one to the image processing device in real time to calculate the contrast of the series of reference images; Determine the optimal positional relationship corresponding to the best contrast among the contrasts of the series of reference images; The imaging component and the light source component are locked in the optimal positional relationship; The wafer to be tested is placed between the imaging component and the light source component. The wafer to be tested includes a first wafer and a second wafer that are bonded together. The first wafer has a first identifier, and the second wafer has a second identifier. Align the imaging assembly and the light source assembly with the first mark and the second mark; and The imaging component performs microscopic imaging of the first and second identifiers to obtain an alignment image of the wafer to be inspected.

16. The method of claim 15, wherein aligning the imaging assembly and the light source assembly with the reference mark comprises driving at least one of the imaging unit and the light source unit via a linear motion system.

17. The method of claim 15, wherein the positional relationship between the imaging component and the light source component is adjusted by at least one of the following steps: The angle between the imaging component and the x-axis is adjusted by using the first fine-tuning slide. The angle between the imaging component and the y-axis is adjusted by the second fine-tuning slide. The angle between the light source assembly and the x-axis is adjusted using the third fine-tuning slide. The angle between the light source assembly and the y-axis is adjusted using the fourth fine-tuning slide. The displacement of at least one of the imaging assembly and the light source assembly in the z-axis direction is adjusted by means of the fifth fine-tuning slide.

18. The method of claim 17, wherein the angle between the imaging component and the x-axis is adjusted by rotating the first adjusting handle of the first fine-tuning slide, the angle between the imaging component and the y-axis is adjusted by rotating the second adjusting handle of the second fine-tuning slide, the angle between the light source component and the x-axis is adjusted by rotating the third adjusting handle of the third fine-tuning slide, the angle between the light source component and the y-axis is adjusted by rotating the fourth adjusting handle of the fourth fine-tuning slide, and the displacement of at least one of the imaging component and the light source component in the z-axis direction is adjusted by rotating the fifth adjusting handle of the fifth fine-tuning slide.

19. The method of claim 18, wherein locking the imaging component and the light source component in the optimal positional relationship comprises adjusting the imaging component and the light source component to the optimal positional relationship: Tighten the locking knob of the first fine-tuning slide to prevent the first adjusting handle from rotating; Tighten the locking knob of the second fine-tuning slide to prevent the second adjusting handle from rotating; Tighten the locking knob of the third fine-tuning slide to prevent the third adjusting handle from rotating; Tighten the locking knob of the fourth fine-tuning slide to prevent the fourth adjusting handle from rotating; and Tighten the locking knob of the fifth fine-tuning slide to prevent the fifth adjusting handle from rotating.

20. The method of claim 15, wherein aligning the imaging assembly and the light source assembly with the first and second marks comprises driving the imaging unit to move synchronously with the light source unit via a linear motion system.

21. The method of claim 15, further comprising: Remove the wafer to be tested; and While maintaining the optimal positional relationship between the imaging component and the light source component, another wafer to be tested is placed between the imaging component and the light source component for wafer bonding alignment testing.

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