Wafer bonding light source control method, wafer bonding device and computer readable storage medium

Abstract

The invention discloses a wafer bonding light source control method, a wafer bonding device and a computer readable storage medium, and relates to the technical field of wafer manufacturing, a target spectrum value and a current spectrum value are compared, a spectrum difference value is obtained, a spectrum threshold value is obtained, under the condition that the spectrum difference value is larger than the spectrum threshold value, a driving part is controlled to drive an optical filter rotating wheel, and the optical filter rotating wheel is driven to rotate. The current spectral value is adjusted by switching the area of the illumination light filtered by the optical filter on the optical filter rotating wheel, and the spectral difference value is made to be smaller than or equal to the spectral threshold value. According to the arrangement, the optical filter can be adjusted, so that the problem of drifting of a central wave band is effectively inhibited, and the spectrum of illumination light irradiated to the wafer to be detected is always kept stable and is highly matched with the process requirement. Therefore, the quality of the acquired mark image can be guaranteed to reach the standard, a reliable basis is provided for accurate identification and positioning of a visual system, the consistency of wafer detection of the same batch is improved, and the process precision and alignment accuracy of wafer bonding are further effectively improved.

Description

Technical Field

[0001] This application relates to the field of wafer manufacturing technology, and in particular to a method for controlling the light source of wafer bonding, a wafer bonding apparatus, and a computer-readable storage medium. Background Technology

[0002] Wafer-to-wafer bonding, also known as direct wafer bonding, refers to the process of bonding two wafers together. In the field of semiconductor technology, direct wafer bonding technology can achieve wafer-to-wafer three-dimensional integration, that is, bonding two or more wafers with the same or different functions. With the development of technology, the requirements for the alignment accuracy of bonding between two wafers are becoming increasingly stringent.

[0003] However, in actual use, the wafer bonding process is affected by the accuracy of the images captured by the camera. If the mark (alignment mark) image captured by the camera in the wafer bonding process is unclear, it will cause the visual algorithm to identify the positioning deviation of the bonding process, or even fail, resulting in core defects such as wafer alignment error and bonding failure, causing serious consequences such as a sharp drop in yield, wafer scrapping, and production line process interruption. Summary of the Invention

[0004] The purpose of this application is to provide a light source control method, a wafer bonding apparatus, and a computer-readable storage medium for wafer bonding, thereby alleviating or solving the aforementioned technical problems existing in the prior art.

[0005] In a first aspect, embodiments of this application disclose a light source control method for wafer bonding. The light source control method for wafer bonding includes acquiring current optical parameters and target optical parameters of the wafer under test. The current optical parameters include the current spectral value of the wafer under test, and the target optical parameters include the target spectral value of the wafer under test. The target spectral value and the current spectral value are compared to obtain a spectral difference and a spectral threshold. If the spectral difference is greater than the spectral threshold, a driving device is controlled to drive a filter wheel to adjust the current spectral value by switching the area of ​​the illumination light filtered by the filter on the filter wheel, and to make the spectral difference less than or equal to the spectral threshold. If the spectral difference is less than or equal to the spectral threshold, a camera is controlled to acquire image information of the wafer under test.

[0006] Secondly, embodiments of this application disclose a wafer bonding apparatus. The wafer bonding apparatus includes a full-band light source, a filter wheel, a driving component, a spectral detection component, and a camera. The full-band light source emits illumination light to the filter wheel. The filter wheel is equipped with a filter for receiving and filtering the illumination light to form band light, which is used to illuminate the wafer. The camera is used to acquire image information of the wafer. The driving component is connected to the filter. The spectral detection component is used to detect the current optical parameters of the area of ​​the wafer illuminated by the band light. The wafer bonding apparatus also includes an acquisition module, an adjustment module, and an image module. The acquisition module is used to acquire the image of the wafer to be bonded. The system measures the current optical parameters and target optical parameters of the wafer. The current optical parameters include the current spectral value, and the target optical parameters include the target spectral value of the wafer under test. The target spectral value and the current spectral value are compared to obtain the spectral difference. The adjustment module is used to obtain the spectral threshold. When the spectral difference is greater than the spectral threshold, the drive unit drives the filter wheel to adjust the current spectral value by switching the area of ​​the illumination light filtered by the filter on the filter wheel, so that the spectral difference is less than or equal to the spectral threshold. The image module is used to control the camera to acquire image information of the wafer under test when the spectral difference is less than or equal to the spectral threshold.

[0007] Thirdly, embodiments of this application disclose a computer-readable storage medium storing a program that can be loaded by a processor and executed as the wafer bonding light source control method of the first aspect.

[0008] The technical solution adopted in this application can achieve the following beneficial effects: A full-band light source can emit illumination light. Further, a full-band light source can be a laser-driven light source (LDLS), etc., whose emitted illumination light covers a wavelength range of 190nm-1700nm, covering the entire wavelength range from deep ultraviolet (DUV), vacuum ultraviolet (VUV), and visible to near-infrared (NIR). Filters can filter the illumination light to form wavelengths such as near-ultraviolet light and visible light, without restriction. This allows the corresponding wavelength of light to illuminate the corresponding wafer under test. The wavelength of light can match the optical response characteristics of the mark on the wafer under test, resulting in high-contrast, high-edge sharpness, and no loss of detail in the mark imaging after illumination, ensuring accurate mark recognition and positioning by the vision system, including the camera.

[0009] Compared to existing technologies, embodiments of this application can acquire target spectral values ​​through a spectral detection device and compare them with the current spectral parameters of the illumination light. When the spectral difference exceeds a threshold, a control drive device is used to slightly rotate or translate the filter to switch the filtering area used to filter the illumination light. This allows for precise adjustment of the current spectral value (such as center wavelength and bandwidth) of the band light illuminating the wafer under test, effectively suppressing center band drift and ensuring that the spectrum of the band light illuminating the wafer under test is compatible with the bonding process. Specifically, the differences between different areas of the filter are utilized. Even if the light energy of the full-band light source attenuates due to prolonged operation, this application can adjust the center wavelength of the band light by changing the filtering area on the filter used to filter the illumination light, thus ensuring consistent illumination effects for multiple wafers in the same batch. Once the spectral parameters meet the threshold requirements, the camera is then controlled to acquire image information of the wafer under test. This reduces or eliminates imaging differences caused by factors such as light source and wafer characteristics, ensuring that the quality of the acquired mark images meets the standards, providing a reliable basis for accurate identification and positioning by the vision system, improving the consistency of wafer inspection in the same batch, and thus effectively improving the process precision and alignment accuracy of wafer bonding. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a schematic flowchart illustrating a light source control method for wafer bonding, as shown in an exemplary embodiment of this application. Figure 2 This is a schematic flowchart illustrating a light source control method for wafer bonding, as shown in another exemplary embodiment of this application. Figure 3 This is a schematic flowchart illustrating a light source control method for wafer bonding, as shown in another exemplary embodiment of this application. Figure 4 This is a schematic flowchart illustrating a light source control method for wafer bonding, as shown in yet another exemplary embodiment of this application. Figure 5 This is a schematic diagram illustrating a process for obtaining target optical parameters of a wafer under test, as shown in an exemplary embodiment of this application. Figure 6 This is a schematic diagram of the structure of a wafer bonding apparatus shown in an exemplary embodiment of this application; Figure 7This is a schematic diagram illustrating the structure of another wafer bonding device according to an exemplary embodiment of this application; Figure 8 This is a schematic diagram of the structure of the filter wheel and mounting bracket shown in an exemplary embodiment of this application; Figure 9 This is a schematic diagram of the structure of the filter wheel, the light intensity adjustment unit, and the light spot shaping and homogenizing unit, as shown in an exemplary embodiment of this application. Figure 10 This is a schematic diagram of the structure of a wafer bonding apparatus shown in another exemplary embodiment of this application.

[0012] In the diagram: 100, wafer bonding device; 110, full-band light source; 120, filter wheel; 121, filter; 130, driving component; 131, mounting bracket; 140, spectral detection component; 150, camera; 161, acquisition module; 162, adjustment module; 163, image module; 171, reflector; 172, beam splitter; 173, illumination light source device; 180, light intensity adjustment unit; 190, light spot shaping and homogenization unit; 191, microlens array; 192, field lens; 200, wafer. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0014] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0015] In the process of developing this application, the applicant discovered that as the calibration process progresses, the center wavelength of the light illuminating the wafer experiences wavelength drift, causing the actual center wavelength of the output target narrow-band light to deviate from the calibration value. For example, if there are too many wafers in the same batch and the bonding process takes a long time, the light source's lifespan is limited, and its light energy attenuates due to prolonged operation. This causes a shift in the peak wavelength (center wavelength) of the filtered light. Differences in imaging effects among multiple wafers in the same batch can lead to wavelength matching failure in wafer bonding mark imaging, light intensity attenuation, blurred mark images, and visual recognition deviations. This, in turn, can cause positioning errors or even failures in visual algorithms for recognizing the bonding process.

[0016] This application provides a light source control method, a wafer bonding apparatus, and a computer-readable storage medium for wafer bonding. Based on target optical parameters, a filter wheel is driven by a driving component to switch the area of ​​the filtered illumination light on the filter, thereby alleviating or solving the above-mentioned problems.

[0017] The first aspect of this embodiment describes in detail a method for controlling the light source in wafer bonding.

[0018] Figure 1 A flowchart illustrating the light source control method for wafer bonding in this embodiment is shown. Figure 1 As shown, the wafer bonding light source control method of this embodiment is used in the aforementioned wafer bonding apparatus. The wafer bonding light source control method includes the following steps: Step S110: Obtain the current optical parameters and target optical parameters of the wafer under test. The current optical parameters include the current spectral value of the wafer under test, and the target optical parameters include the target spectral value of the wafer under test. Compare the target spectral value and the current spectral value to obtain the spectral difference.

[0019] The current optical parameters and target optical parameters of the wafer under test are acquired. The current optical parameters can be automatically acquired by a spectrometer, and include the current spectral value, which includes the center wavelength and bandwidth of the light illuminating the wafer under test. In other words, the current spectral value includes the center wavelength and bandwidth of the light band without limitation. The target optical parameters can be pre-calibrated optimal standards that combine wafer material, mark structure, and visual recognition requirements, so that the camera can acquire the best image information. The target optical parameters can be manually input, pre-stored, or automatically acquired. It should be noted that, compared to pre-stored programs, automatic acquisition involves the spectrometer acquiring the current optical parameters of the sample wafer, which is automatically used as the target optical parameters of the wafer under test. It should also be noted that the sample wafer is selected from multiple wafers under test in the same batch as a reference.

[0020] By comparing the target spectral value with the current spectral value, the spectral difference between the two is calculated. This difference directly reflects the degree of deviation between the center wavelength and bandwidth of the current illumination light and the optimal standard required for wafer imaging. This provides a basis for subsequent adjustment of the illumination light spectrum, ensures the optical compatibility between the wavelength light and the wafer under test, and lays a data foundation for clear mark imaging.

[0021] Step S120: Obtain the spectral threshold. If the spectral difference is greater than the spectral threshold, control the drive to drive the filter wheel to adjust the current spectral value by switching the area of ​​the illumination light filtered by the filter on the filter wheel, and make the spectral difference less than or equal to the spectral threshold.

[0022] A spectral threshold is obtained, which can be manually input or pre-configured in the wafer bonding device. The spectral threshold includes a center wavelength threshold, a bandwidth threshold, etc. The specific content of the spectral threshold is determined by manual selection or automatic selection by a program, and the selected spectral threshold is at least one of the center wavelength threshold, bandwidth threshold, etc. Preferably, it allows multiple parameters of the current wavelength band light to simultaneously meet the spectral threshold, further improving the irradiation effect. In one embodiment, the selected spectral threshold is a center wavelength threshold, which can be 0.2 nm. In another embodiment, the selected spectral threshold is a bandwidth threshold, which can be 0.3 nm. In yet another embodiment, the selected spectral threshold includes a center wavelength threshold and a bandwidth threshold; the center wavelength threshold can be 0.2 nm, and the bandwidth threshold can be 0.3 nm, without limitation. For ease of description, the following description assumes the spectral threshold is the center wavelength.

[0023] When the spectral difference exceeds the spectral threshold, the drive unit moves the filter wheel. The wafer bonding apparatus sends a command to the drive unit when it determines that the spectral difference exceeds the threshold. The drive unit then rotates or moves the filter wheel horizontally, changing the filtering area of ​​the illumination light by switching the filters on the wheel. This adjusts the current spectral value, reducing the spectral difference to within the spectral threshold range. Specifically, the center wavelength difference must be less than or equal to the center wavelength threshold, and the bandwidth value must be less than or equal to the bandwidth threshold. This ensures that the inspection conditions for wafers in the same batch are identical, resulting in consistent illumination effects across multiple wafers in the same batch. This improves inspection accuracy and consistency, and ultimately enhances the precision of the wafer bonding process.

[0024] Specifically, the same filter includes different first and second regions. The first region filters the illumination light to form a first ray, and the first wavelength light illuminates the wafer under test. As the illumination duration of the full-band light source increases, the illumination light from the full-band light source attenuates. After detection and comparison, the difference in the center wavelength of the first ray is greater than the center wavelength threshold. A driving element drives the filter wheel to translate or rotate, switching the filter area from the first region to the second region to form a second ray. The center wavelength of the second ray is different from that of the first ray. The second ray illuminates the wafer under test, and the difference in the center wavelength of the second ray is less than or equal to the center wavelength threshold, ensuring that the wavelength spectrum of the light illuminating the wafer under test is compatible with the bonding process. Preferably, after the filter wheel switches the corresponding filter to the optical path, the driving element restricts the rotation of the filter wheel. The driving element drives the filter wheel to move along a first direction and a second direction, wherein the first direction, the second direction, and the rotation direction of the filter wheel intersect each other. This allows the filter wheel and the filters on it to move in parallel, reducing the shaking of the filter wheel and the filters on it, and improving the adjustment accuracy.

[0025] It should be noted that the size of the filter is larger than the size of the light spot illuminating it; in other words, the illumination light only illuminates a portion of the filter. Furthermore, because the filter coating can vary, the same illumination light passing through different areas of the same filter can produce light of different center wavelengths. For example, if the filter coating uses a vacuum deposition process, the thickness of the surface coating will not be uniform. Illumination light passing through coatings of different thicknesses will form light of different wavelengths. The embodiments of this application can utilize the characteristic that different areas of the filter have different filtering effects to modify the differences between different areas of the filter, thereby adjusting the center wavelength of the light wave. Even if the illumination light changes, filter calibration can be used to ensure that the testing conditions for multiple wafers in the same batch are identical and stable.

[0026] The embodiments of this application can acquire the target spectral value through a spectral detection device and compare it with the current spectral parameters of the band light. When the spectral difference exceeds a threshold, the control drive device drives the filter to switch the filtering area, making precise adjustments to the current spectral value, thereby effectively suppressing the center band drift problem and ensuring that the spectral value of the band light irradiating the wafer under test remains stable and compatible with the process requirements.

[0027] Step S130: When the spectral difference is less than or equal to the spectral threshold, control the camera to acquire image information of the wafer under test.

[0028] When the spectral difference is less than or equal to the spectral threshold, the spectral values ​​such as the center wavelength and bandwidth of the band light illuminating the wafer under test are within the same range as the target spectral parameters. Multiple wafers under test in the same batch are detected and adjusted in this way, eliminating imaging differences caused by light sources, wafer characteristics, etc. This ensures that the quality of the acquired mark images meets the standards, provides a reliable basis for the accurate identification and positioning of the vision system, improves the consistency of wafer detection in the same batch, and effectively improves the process precision and alignment accuracy of wafer bonding.

[0029] This setting ensures that the camera captures images under optimal spectral parameters and the best contrast between the wafer mark and the substrate. This effectively reduces or avoids problems such as blurry images, loss of detail, and excessive noise caused by spectral deviations. The captured images clearly present the key features of the mark, such as its outline and texture, providing high-quality image data support for subsequent core process steps such as visual recognition and wafer alignment. This ensures the accuracy of wafer bonding alignment and process stability.

[0030] According to one optional implementation, please refer to Figure 2 Before step S110: obtaining the current optical parameters and target optical parameters of the wafer under test, at least the following steps are included: Step S210: Obtain the filter information of the wafer under test. Based on the filter information, control the driving component to drive the filter wheel so that the corresponding filter is switched to the optical path of the illumination light, so as to form the corresponding wavelength light to irradiate the wafer under test.

[0031] Obtain the filter information of the wafer under test. The filter information can be manually entered or pre-stored, and is not limited in type. The filter information includes the type of wafer under test, its corresponding filter model, and the corresponding wavelength range to be filtered. For example, in one embodiment, the wafer under test can be a silicon-based wafer, and its corresponding filter is a visible light wavelength filter. In another embodiment, the wafer under test can be a gallium nitride wafer, and its corresponding filter is a blue-violet wavelength filter; further details are omitted here.

[0032] Based on the filter information, the controller drives the filter wheel. After receiving the filter information, the controller can control the drive to send corresponding control commands, which in turn drive the filter wheel to rotate. The corresponding filter switches to the illumination path of the full-band light source, allowing the illumination light to pass through the filter and form a wavelength of light compatible with the wafer under test. This wavelength of light is directed along a preset optical path to illuminate the mark area of ​​the wafer under test, allowing the wavelength of light to form a good optical response with the wafer material, improving the contrast between the mark area and the substrate, making the wafer image captured by the camera clearer and more detailed. At the same time, the automated and precise switching of the filter wheel replaces the tedious manual operation of changing filters, greatly improving the efficiency and accuracy of optical path adjustment, and enhancing the stability and yield of the overall bonding process.

[0033] According to one optional implementation, please refer to Figure 3 Step S210: Obtaining the filter information of the wafer under test includes: Step S211: Obtain the material information of the wafer to be tested, and determine the filter information of the wafer to be tested based on the material information of the wafer to be tested.

[0034] Obtaining the material information of the wafer under test, including the substrate material, surface coating type, and doping composition, is not limited. Different materials correspond to different optical properties in wafers under test. For example, silicon-based wafers have weaker absorption and better imaging contrast in the visible light band, while gallium nitride wafers are suitable for the ultraviolet to blue-violet light band. Wafers with silicon oxide coatings will exhibit enhanced reflection of specific wavelengths of light due to the coating thickness. Based on the acquired material information, the corresponding filter information is determined by referring to a pre-calibrated database of materials and filters for the wafer under test. This database may include the compatible filter model, the corresponding filtered wavelength range, and the center wavelength. For example, in one scenario, if the wafer under test is detected as a pure silicon substrate, a filter that filters the visible light band will be matched. In another scenario, if the wafer under test is detected as a gallium nitride wafer, a filter that filters the blue-violet light band will be matched. This ensures that the filter can filter out illumination light compatible with the wafer material.

[0035] In subsequent wafer bonding processes, the corresponding matching filter can be quickly switched into the illumination light path simply by controlling the filter wheel rotation via a drive component. This allows the filter to accurately filter the illumination light emitted from the full-band light source, filtering out the target wavelength light that matches the wafer material. This effectively avoids problems such as blurry mark imaging and insufficient contrast caused by the mismatch between the filter and the wafer material. At the same time, the automated rotation and switching of the filter wheel replaces the manual operation of changing the filter, greatly improving the efficiency and accuracy of optical path adjustment. This adapts to the batch testing needs of wafers with different materials, ensuring the imaging quality of the wafer mark from the source of light source wavelength compatibility.

[0036] According to one optional implementation, please refer to Figure 4 Step S130: Before controlling the camera to acquire image information of the wafer under test when the spectral difference is less than or equal to the spectral threshold, the following steps are also included: Step S310: Obtain the current optical parameters and target optical parameters of the wafer under test. The target optical parameters also include the target light intensity, and the current optical parameters include the current light intensity. Compare the target light intensity and the current light intensity to obtain the light intensity difference.

[0037] The current optical parameters and target optical parameters of the wafer under test are obtained. The current optical parameters can be automatically obtained by a spectrometer, and include the target light intensity without limitation.

[0038] The light intensity difference is obtained by comparing the target light intensity with the current light intensity. The current optical parameters of the wafer under test and the target optical parameters are obtained, and the two light intensities are numerically compared and calculated to obtain the light intensity difference. The light intensity difference can intuitively reflect the degree of deviation between the current light intensity and the optimal imaging light intensity.

[0039] Step S320: Obtain the light intensity threshold. Based on the light intensity difference and the light intensity threshold, adjust the light intensity adjustment unit of the wafer bonding device so that the light intensity difference is less than or equal to the light intensity threshold.

[0040] The light intensity threshold is obtained, which can be manually entered or pre-configured in the wafer bonding device.

[0041] The intensity adjustment unit of the wafer bonding device is adjusted based on the intensity difference and intensity threshold. By comparing the intensity difference and the intensity threshold, the intensity adjustment unit of the wafer bonding device is adjusted according to the judgment result to increase or decrease the intensity of the current illumination light, so that the intensity difference is controlled within the intensity threshold range, ensuring that the wavelength light is adapted to the imaging requirements of the wafer.

[0042] The light intensity difference is the difference between the current light intensity and the target light intensity, and the light intensity modulation unit can be a variable aperture. In one case, when the light intensity difference is greater than the light intensity threshold and the light intensity difference is negative, the variable aperture is controlled to increase its aperture size, thus keeping the light intensity difference within the light intensity threshold range. In another case, when the light intensity difference is greater than the light intensity threshold and the light intensity difference is positive, the variable aperture is controlled to decrease its aperture size, thus keeping the light intensity difference within the light intensity threshold range. This setting ensures that wafers in the same batch have the same illumination intensity, improving the consistency of wafer inspection within the same batch, and thus effectively improving the process accuracy and alignment accuracy of wafer bonding.

[0043] According to one optional implementation, please refer to Figure 5 Step S110: Obtaining the target optical parameters of the wafer under test includes: Step S111: Control the driving component to drive the filter wheel so that multiple filters on the filter wheel filter the illumination light in sequence to form multiple different wavelengths of light and irradiate the sample wafer.

[0044] A control drive unit drives a filter wheel, causing multiple filters on the wheel to sequentially filter the illumination light. Specifically, a control command is sent to the drive unit, which rotates the filter wheel at a preset rate, allowing multiple different types of filters on the wheel to sequentially switch onto the optical path of the illumination light. Each filter selectively filters the full-band illumination light, forming different wavelengths of light. This wavelength of light is then directed onto the sample wafer along a preset optical path. For example, the filters on the wheel can sequentially filter out blue-violet light, red visible light, and other wavelengths of light, illuminating the sample wafer. It should be noted that the sample wafer can be selected from the same batch of wafers to be tested, and used as an optical reference. Sequentially illuminating the sample wafer with multiple wavelengths of light facilitates subsequent selection of the optimal testing method for wafer imaging.

[0045] Step S112: When the sample wafer is illuminated by light of each wavelength, control the camera to acquire images of the sample wafer, and obtain the current optical parameters corresponding to each image information through the spectral detection device.

[0046] When the sample wafer is illuminated by light of each wavelength, the system controls the camera to acquire images of the sample wafer. Specifically, during the illumination of the sample wafer by the corresponding wavelength of light filtered by each filter, the system controls the camera to acquire high-definition, unbiased images of the mark area of ​​the sample wafer, thus obtaining the wafer image corresponding to each wavelength of light.

[0047] Simultaneously, when the sample wafer is illuminated by light of each wavelength band, the spectral detection device can detect the corresponding current optical parameters of the currently illuminated wafer in real time. These current optical parameters include the center wavelength, bandwidth, light intensity, and filter information of the wavelength band region on the sample wafer. The data includes a one-to-one correspondence between the wavelength band light, its corresponding filter, the wafer image, and the optical parameters.

[0048] Step S113: Compare the contrast of multiple images, determine the image with the highest contrast, and determine its corresponding current optical parameters as the target optical parameters of the wafer under test, and determine its corresponding filter information as the filter information of the wafer under test.

[0049] By comparing the contrast of multiple images, the image with the highest contrast is determined. Contrast analysis and comparison are performed on images of multiple sample wafers. Furthermore, among the images of multiple sample wafers, the image with the most significant difference in brightness between the mark area and the wafer substrate, the clearest mark outline, and the most complete details is selected, resulting in the highest contrast image.

[0050] After identifying the image with the highest contrast, its corresponding current optical parameters are set as the target optical parameters for the wafer under test, and its corresponding filter information is also set as the filter information for the wafer under test. Subsequently, the current optical parameters corresponding to the high-contrast image are calibrated as the target optical parameters for wafers under test in the same batch. Furthermore, the center wavelength, bandwidth, light intensity, and filter information corresponding to this image are simultaneously set as the center wavelength, bandwidth, light intensity, and compatible filter information for wafers under test in the same batch. Using the high-contrast image of the sample wafer as a benchmark replaces the existing method of manually setting parameters, ensuring that the calibrated target optical parameters and filter information better match the optical characteristics of the wafer under test. This provides a more standardized basis for subsequent mass production and inspection of the same batch of wafers under test, ensuring imaging quality and visual recognition accuracy. This setup improves the consistency of wafer inspection within the same batch, thereby effectively improving the process accuracy and alignment accuracy of wafer bonding.

[0051] The second aspect of this embodiment provides a detailed description of the wafer bonding apparatus.

[0052] Embodiments of this application provide a wafer bonding apparatus 100. Figure 6 A schematic diagram of the wafer bonding apparatus 100 of this embodiment is shown. Figure 6As shown, the wafer bonding apparatus 100 may include a full-band light source 110, a filter wheel 120, a driver 130, a spectral detection device 140, and a camera 150. A filter 121 is disposed on the filter wheel 120, and the full-band light source 110 emits illumination light to the filter 121. The full-band light source 110 may be a laser-driven light source or a halogen light source, etc., and its emitted illumination light covers a wavelength range of 190nm-1700nm, such as covering the deep ultraviolet (DUV), vacuum ultraviolet (VUV), and visible to near-infrared (NIR) wavelengths. The filter 121 receives and filters the illumination light to form banded light, which can be transmitted to the wafer 200 via optical fiber so that the banded light can illuminate the wafer 200. For example, filter 121 can be a deep ultraviolet narrowband filter, a near ultraviolet narrowband filter, a visible light multi-band narrowband filter, a near-infrared narrowband filter, and a gradient neutral density filter 121, etc., which will not be elaborated here. Among them, wafer 200 includes wafers to be tested and sample wafers, etc., and is not limited.

[0053] Camera 150 is used to acquire image information from wafer 200. It should be noted that different wavelengths of light illuminating wafer 200 will result in different image information acquired by camera 150. This application can obtain different wavelengths of light by changing different types of filters to filter the illumination light. For example, in one case, silicon tends to be transparent under near-infrared light in the image acquired by camera 150.

[0054] The drive unit 130 is connected to the filter wheel 120 via a transmission. The drive unit 130 can be a servo motor, engine, etc. More specifically, the drive unit 130 includes a servo motor and a ball screw, which are connected in a transmission manner, and the ball screw is connected to the filter wheel 120 via a transmission manner. This ensures that the switching accuracy of the filter 121 is less than or equal to 0.005° and the switching response time is less than or equal to 0.3s, ensuring the accuracy and efficiency of spectral switching. No limitations are imposed. The filter wheel 120 rotates under the drive of the drive unit 130, allowing its infrared light filter to penetrate the double-layer silicon wafer to identify the mark image.

[0055] The spectral detection device 140 can be a spectrometer, spectral sensor, or spectrophotometer, etc., and is not limited thereto. The spectral detection device 140 is used to detect the current optical parameters of the area of ​​the wafer 200 illuminated by the wavelength light. The current optical parameters can be light intensity, center wavelength, or bandwidth, etc., and are not limited thereto. It should be noted that light intensity reflects the amount of light energy passing through the optical path per unit time, directly determining the brightness of the image. The center wavelength refers to the wavelength value corresponding to the peak light intensity in the target wavelength light after filtering. The bandwidth, or bandwidth, is the wavelength coverage range of the target wavelength light after filtering; it is based on the center wavelength and includes a wavelength range where the light intensity reaches a certain proportion of the peak value.

[0056] Please see Figure 7 The wafer bonding apparatus 100 also includes an acquisition module 161, an adjustment module 162, and an image module 163. The acquisition module 161 is used to acquire the current optical parameters and target optical parameters of the wafer 200 under test. The current optical parameters include the current spectral value, and the target optical parameters include the target spectral value of the wafer 200 under test. The target spectral value and the current spectral value are compared to obtain the spectral difference.

[0057] The adjustment module 162 is used to obtain the spectral threshold. When the spectral difference is greater than the spectral threshold, the control driver 130 drives the filter 121 to switch the area through which the illumination light is transmitted by the filter 121, so as to adjust the current spectral value.

[0058] The image module 163 is used to control the camera 150 to acquire image information of the wafer 200 under test when the spectral parameters are less than or equal to the spectral threshold.

[0059] Please refer again to the embodiments in this application. Figure 6 The wafer bonding apparatus 100 also includes a reflector 171 and a beam splitter 172. The reflector 171 reflects wavelength light to the beam splitter 172, and the beam splitter 172 reflects wavelength light onto the wafer 200 to form image light. The image light is then reflected from the wafer 200 to the camera 150, and the image light passes through the beam splitter 172 and is transmitted to the camera 150. The reflector 171 and the beam splitter 172 work together to achieve optical path multiplexing of illumination light and image light. The reflector 171 first directionally reflects the target wavelength light, which has been processed by filtering, to the beam splitter 172. The beam splitter 172 then further vertically reflects the wavelength light onto the surface of the wafer 200 under test, providing illumination light for the mark area of ​​the wafer 200. At the same time, the beam splitter 172 has unidirectional optical transmission characteristics, so the image light formed after the surface of the wafer 200 is illuminated can directly pass through the beam splitter 172 and be transmitted along a preset optical path to the imaging end of the camera 150. This setup allows the illumination light and image light to share the core optical path, ensuring a precise correspondence between the illumination light's position and the camera 150's acquisition area, avoiding imaging deviations caused by optical path offsets. It also simplifies the device's optical path structure, reduces the use of optical components, lowers stray light interference, effectively improves the clarity of the acquired mark image, and provides a stable optical foundation for subsequent visual recognition in the bonding process.

[0060] In one implementation, please refer again. Figure 6The full-band light source 110 is a laser-driven light source, and the emitted illumination light wavelength range of the full-band light source 110 can be 190nm-1700nm. The full-band light source 110 can be a laser-driven light source or a halogen light source, etc., and the illumination light can be a mixed light composed of multiple different wavelengths. Its emitted illumination light covers a wavelength range of 190nm-1700nm, such as covering the deep ultraviolet (DUV), vacuum ultraviolet (VUV), and visible to near-infrared (NIR) wavelengths. This wavelength range not only includes the core ultraviolet and visible light wavelengths required for semiconductor wafer 200mark imaging, but also adapts to the optical response characteristics of wafers 200 with different materials, sizes, and pattern structures. It can provide matching illumination wavelength selection for various wafer 200 bonding scenarios. Compared with traditional narrow-band light sources, laser-driven light sources have stronger wavelength coverage and higher light intensity stability, which can effectively avoid the problem of poor imaging adaptability caused by a single light source wavelength.

[0061] In another implementation, please refer to Figure 6 as well as Figure 8 The number of filters 121 can be multiple, such as two, three, or even more, without limitation. Multiple filters 121 are used to filter light of different wavelengths. The wafer bonding apparatus 100 also includes a filter wheel 120. Multiple filters 121 are spaced apart along the circumference of the filter wheel 120 to receive and filter illumination light to form wavelengths, which are then used to illuminate the wafer 200. For example, the multiple filters 121 may include a deep ultraviolet narrowband filter, a near-ultraviolet narrowband filter, a visible multi-band narrowband filter, a near-infrared narrowband filter, and a gradient neutral density filter 121, etc. In one embodiment, the center wavelength of the light filtered by the deep ultraviolet narrowband filter is 200nm-280nm, the bandwidth is less than or equal to 3nm, and the light transmission efficiency is greater than or equal to 93%. In another embodiment, the center wavelength of the light filtered by the near ultraviolet narrowband filter is 320nm-380nm, the bandwidth is less than or equal to 3nm, and the light transmission efficiency is greater than or equal to 93%. Further details are omitted here. Each filter 121 filters out target wavelengths of light corresponding to different wavelengths, and multiple filters 121 are evenly spaced along the circumferential interval of the filter wheel 120. The rotation direction of the filter wheel 120 is as follows: Figure 8As shown in L1, it can rotate clockwise or counterclockwise around its circumference. The filter wheel 120 can quickly switch between different filters 121 by rotating, and the illumination band can be adjusted without disassembling and replacing the filters 121. It can adapt to the illumination band requirements of different wafers 200 and different bonding processes. The setting of the filter wheel 120 can make the switching of filters 121 more efficient and the positioning more accurate, which can effectively shorten the process time of band switching and improve the automation efficiency of the device. At the same time, the independent setting of multiple filters 121 can ensure the accuracy of filtering of each band and avoid cross-band interference.

[0062] Better, such as Figure 8 As shown, the drive unit 130 may further include a mounting bracket 131 and multiple drive motors. The filter wheel 120 is movably mounted on the mounting bracket 131, and the multiple drive motors can drive the filter wheel 120 along a first direction (e.g., Figure 8 (as shown in the x-axis direction) and the second direction ... Figure 8 The filter wheel 120 moves along the z-axis and rotates. For example, the mounting bracket 131 includes a base, a first arm, and a second arm. The drive motor includes a first drive motor, a second drive motor, and a third drive motor. The filter wheel 120 is connected to the output shaft of the first drive motor. The first drive motor is movably mounted on the first arm of the mounting bracket 131. The first arm is movably connected to the second arm along a first direction, and the second arm is movably connected to the base along a second direction. The second drive motor drives the first arm to move relative to the second arm, and the third drive motor drives the second arm to move relative to the base. Preferably, the base, the first arm, and the second arm are all provided with guide rails, allowing the corresponding components to move along the guide rails to drive the filter wheel 120 to move stably along the first and second directions. This arrangement allows the corresponding area of ​​the filter 121 to be accurately positioned in the optical path of the illumination light, reducing the difficulty of adjusting the filter wheel 120 and improving the stability and reliability of the filter 121 adjustment.

[0063] In another embodiment, the full-band light source 110 is a laser-driven light source, and the illumination light emitted by the full-band light source 110 has a wavelength range of 190nm-1700nm. Multiple filters 121 are used to filter light of different wavelengths. The wafer bonding apparatus 100 also includes a filter wheel 120, with multiple filters 121 spaced apart along the circumference of the filter wheel 120 to receive and filter the illumination light to form wavelength light. Different wavelengths of light irradiating the wafer 200 result in different image information captured by the camera 150. This application can obtain different wavelengths of light by changing different types of filters to filter the illumination light, which will not be elaborated further here.

[0064] In the embodiments of this application, please refer to Figure 9 The wafer bonding apparatus 100 further includes at least one of an intensity modulation unit 180 and a spot shaping and homogenizing unit 190. In one embodiment, the spot shaping and homogenizing unit 190 is used to collimate and homogenize the illumination light. Further, the spot shaping and homogenizing unit 190 is disposed in the output light path of the full-band light source 110. It first collimates and homogenizes the original illumination light emitted from the laser-driven light source, correcting the divergent light emitted by the light source into parallel light, while simultaneously making the energy distribution of the illumination light more uniform, avoiding the problem of bright center and dark edge illumination.

[0065] For further details, please refer to Figure 9 The beam shaping and homogenization unit 190 can homogenize the illumination light, shaping the beam into a uniform beam that matches the size of the wafer 200, so that the beam size is continuously adjustable within the range of 10mm-150mm, and the uniformity of the beam after homogenization is greater than or equal to 95%. The beam shaping and homogenization unit 190 includes a microlens array 191 and a field lens 192. The microlens array 191 is disposed in the output light path of the full-band light source 110. The microlens array 191 receives the illumination light and outputs it to the field lens 192. The field lens 192 receives the illumination light and outputs it to the light intensity modulation unit 180. The microlens array 191 is directly positioned in the output optical path of the full-band light source 110. The original illumination light emitted from the light source first enters the microlens array 191, which splits the entire illumination beam into multiple independent micro sub-beams, achieving wavefront segmentation and preliminary homogenization of the original light. The segmented sub-beams are then directed to the subsequent field lens 192. After receiving all the sub-beams, the field lens 192 uses its own optical properties to spatially superimpose and re-collimate the dispersed sub-beams, allowing the energy of the sub-beams to compensate for each other, thus completely solving the problem of uneven energy in the original illumination light. At the same time, it shapes the superimposed beam into a regular and standard parallel light spot. This provides a high-quality base light source for subsequent intensity tuning and band filtering, effectively avoiding the problem of excessively strong or weak local illumination on the wafer 200 caused by uneven light spot.

[0066] In another embodiment, the intensity adjustment unit 180 is used to adjust the intensity of the illumination light and emit the illumination light. Further, the intensity adjustment unit 180 emits the illumination light to the filter 121. The intensity adjustment unit 180 controls the light intensity within the optimal range for acquisition by the adapter camera 150, avoiding problems such as low filtering efficiency and band shift caused by uneven light intensity and light pattern divergence in the filter 121. Simultaneously, on wafers 200 tested in the same batch, this can adjust the light spot to maintain consistency, ensuring stable light intensity and uniform light spot of the target band after filtering, thus improving the bonding effect of the wafers 200.

[0067] For further information, please refer to [link / reference]. Figure 9The intensity adjustment unit 180 includes a variable aperture, which is electrically controllable and has an intensity adjustment range of 1%-100%, with an adjustment accuracy of less than or equal to ±0.3%. The variable aperture receives the illumination light emitted from the light spot shaping and homogenizing unit 190, adjusts the intensity of the illumination light, and directs the illumination light to the filter 121. By adjusting the aperture size, precise control of the illumination light throughput is achieved, thereby adjusting the emitted illumination light intensity. Increasing the aperture size increases the throughput and intensity of the illumination light, while decreasing the aperture size decreases the throughput and intensity of the illumination light. The adjusted illumination light is then directed through the variable aperture to the filter 121 for band filtering, eliminating the need for frequent attenuator replacements as in existing technologies and significantly improving the automation level of the device. Meanwhile, the variable aperture can also filter out stray beams at the edge of the illumination light while adjusting the light intensity, further improving the purity of the illumination light and reducing the interference of stray light on subsequent filtering and imaging, so that the light intensity of the target wavelength light that finally illuminates the wafer 200 is more stable and the light spot is purer.

[0068] In another embodiment, the wafer bonding apparatus 100 further includes an intensity adjustment unit 180 and a spot shaping and homogenizing unit 190. The spot shaping and homogenizing unit 190 is disposed in the output light path of the full-band light source 110. The spot shaping and homogenizing unit 190 is used to collimate and homogenize the illumination light and output the illumination light to the intensity adjustment unit 180. The intensity adjustment unit 180 is used to adjust the light intensity of the illumination light and output the illumination light to the filter 121. The intensity adjustment unit 180 and the spot shaping and homogenizing unit 190 cooperate to adjust the light pattern and light intensity of the illumination light, avoiding the problems of low filtering efficiency and band shift of the filter 121 caused by uneven light intensity and light pattern divergence. This ensures the stability of the light intensity and uniformity of the target band light after filtering, thereby allowing the illumination light to achieve the best imaging standard.

[0069] In addition, in one case, the wafer bonding apparatus 100 also includes a collimating and enhancing lens group, which is composed of multiple aspherical lenses with a collimation accuracy of less than or equal to 0.05 mrad (milliradians). The collimating and enhancing lens group can convert the illumination light emitted from the full-band light source 110 into a collimated beam with extremely high parallelism.

[0070] In this embodiment, the wafer bonding apparatus 100 further includes an automatic cleaning unit. The automatic cleaning unit employs a combination of inert gas (nitrogen, etc.) purging and electrostatic dust removal. Both the inert gas purging and electrostatic dust removal structures are located on the light-incoming and light-outcoming surfaces of the filter 121, enabling real-time removal of dust and electrostatic impurities from the surface of the filter 121. This avoids stray light interference and reduced light transmission efficiency, ensuring image clarity. Furthermore, the wafer bonding apparatus 100 also includes an anti-reflective protective window. This window can be positioned between the optical path and the wafer 200. It allows light to pass through in a specific wavelength range. The anti-reflective protective window is made of quartz material with an anti-reflective coating, achieving a light transmission efficiency greater than or equal to 98%. It isolates dust and moisture from the cleanroom, protecting internal optical components and reducing light intensity loss.

[0071] In another configuration, the wafer bonding apparatus 100 also includes a dustproof sealed housing, within which components including the full-band light source 110, filter wheel 120, drive unit 130, spectral detector 140, and camera 150 are housed. The dustproof sealed housing can be made of stainless steel and filled with inert gas to form a slightly positive pressure protective chamber, achieving an IP67 protection rating. This ensures long-term stable operation of the system in a cleanroom environment and prevents dust contamination from affecting optical performance.

[0072] In some other embodiments, please refer to Figure 10 The wafer bonding apparatus 100 also includes an illumination light source device 173, which is disposed on the side of the beam splitter 172 away from the camera 150. For example, in one case, the illumination light source device 173 may include a visible light source, such as a red light source, a blue light source, etc., without limitation. In another case, the illumination light source device 173 may also include a full-band light source, a filter wheel, a driving component, etc., which can also drive the filter to rotate slightly by controlling the driving component to switch the filtering area used to filter the illumination light, without limitation. In the alignment process of wafer 200 bonding, the illumination light source device 173 can form transmitted illumination from the back of the wafer 200 to be bonded, forming a dual-light source illumination mode with the original front illumination. The illumination light source device 173 allows light to penetrate the wafer 200, making the mark features at the bonding point clearer. This effectively compensates for the visual blind spots of single front illumination, improves the image contrast and edge sharpness of the alignment marks of the two wafers 200, and allows the vision system to accurately identify the alignment marks of the two wafers 200 and complete nanometer-level precise positioning. This avoids mark recognition deviation caused by insufficient illumination of the stacked wafers 200, which can ensure the accuracy of the bonding alignment of the two wafers 200, reduce bonding failures and pad misalignment caused by misalignment, and further improve the overall process yield and stability of wafer 200 bonding.

[0073] The third aspect of this embodiment provides a detailed description of the readable storage medium.

[0074] The readable storage medium of this embodiment stores a program or instructions. When the program or instructions are executed by a processor, they implement the steps of the wafer bonding light source control method as described in any of the technical solutions in this embodiment. The implementation of each of the above operations can be found in the preceding method embodiments, and will not be repeated here.

[0075] The readable storage medium can be an electronic storage device such as flash memory, electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), hard disk, or ROM. Optionally, the readable storage medium can include a non-transitory computer-readable storage medium. The computer-readable storage medium has storage space for program code that performs any of the method steps described above. This computer program code can be read from or written to one or more computer program products. The computer program code can be compressed, for example, in a suitable form.

[0076] In other cases, this embodiment may also provide an electronic device that is electrically connected to a full-band light source 110, a driver 130, a spectral detector 140, and a camera 150 for control by the electronic device. The electronic device includes a memory and a processor, which are connected. The memory stores programs or instructions that can run on the processor. When executed by the processor, the programs or instructions implement the steps of the wafer bonding light source control method as described in any of the technical solutions in this embodiment. The memory may be independent or integrated with the processor.

[0077] The memory may include random access memory (RAM) or read-only memory (ROM). The memory can be used to store instructions, programs, code, code sets, or instruction sets. The memory may include a program storage area and a data storage area. The program storage area may store instructions for implementing an operating system, instructions for implementing at least one function (such as touch functionality, sound playback functionality, image playback functionality, etc.), and instructions for implementing the various method embodiments described above. The data storage area may also store data created during the use of the electronic device (such as audio and video data, chat log data, etc.).

[0078] A processor may include one or more processing cores. It can connect to various parts of the electronic device via various interfaces and lines, and can perform various functions and process data by running or executing instructions, programs, code sets, or instruction sets stored in memory, and by calling data stored in memory. Optionally, the processor can be implemented using at least one hardware form of digital signal processing (DSP), field-programmable gate array (FPGA), or programmable logic array (PLA). The processor can integrate one or more of the following: central processing unit (CPU), graphics processing unit (GPU), and modem. The CPU primarily handles the operating system, user interface, and applications; the GPU is responsible for rendering and drawing the displayed content; and the modem handles wireless communication. It is understood that the modem may also be implemented separately as a communication chip, without being integrated into the processor.

[0079] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0080] Furthermore, it should be noted that the scope of the methods and apparatus in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. In addition, features described with reference to certain examples may be combined in other examples.

[0081] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A method for controlling the light source in wafer bonding, characterized in that, The light source control method for wafer bonding includes: The current optical parameters and target optical parameters of the wafer under test are obtained. The current optical parameters include the current spectral value of the wafer under test, and the target optical parameters include the target spectral value of the wafer under test. The target spectral value and the current spectral value are compared to obtain the spectral difference. A spectral threshold is obtained. If the spectral difference is greater than the spectral threshold, the driving unit is controlled to drive the filter wheel to adjust the current spectral value by switching the area of ​​the illumination light filtered by the filter on the filter wheel, and to make the spectral difference less than or equal to the spectral threshold. When the spectral difference is less than or equal to the spectral threshold, the camera is controlled to acquire image information of the wafer under test.

2. The light source control method for wafer bonding according to claim 1, characterized in that, Before obtaining the current and target optical parameters of the wafer under test, the following steps are also included: The filter information of the wafer under test is obtained, and the filter wheel is driven by the driving component according to the filter information, so that the corresponding filter is switched to the optical path of the illumination light, so as to form the corresponding wavelength light to irradiate the wafer under test.

3. The light source control method for wafer bonding according to claim 2, characterized in that, Obtaining the filter information of the wafer under test includes: The material information of the wafer under test is obtained, and the filter information of the wafer under test is determined based on the material information of the wafer under test.

4. The light source control method for wafer bonding according to claim 1, characterized in that, Before controlling the camera to acquire image information of the wafer under test, the method further includes: The current optical parameters and target optical parameters of the wafer under test are obtained. The target optical parameters include the target light intensity, and the current optical parameters include the current light intensity. The light intensity difference is obtained by comparing the target light intensity and the current light intensity. A light intensity threshold is obtained, and the light intensity adjustment unit of the wafer bonding device is adjusted according to the light intensity difference and the light intensity threshold so that the light intensity difference is less than or equal to the light intensity threshold.

5. The light source control method for wafer bonding according to any one of claims 1-4, characterized in that, The acquisition of the target optical parameters of the wafer under test includes: The driving component is controlled to drive the filter wheel so that multiple filters on the filter wheel sequentially filter the illumination light to form multiple wavelengths of light and illuminate the sample wafer. When the sample wafer is illuminated by light of each wavelength, the camera is controlled to acquire images of the sample wafer, and the current optical parameters corresponding to each image information are obtained through the spectral detection device; By comparing the contrast of multiple images, the image with the highest contrast is determined, and its corresponding current optical parameters are determined as the target optical parameters of the wafer under test, and its corresponding filter information is determined as the filter information of the wafer under test.

6. The light source control method for wafer bonding according to claim 1, characterized in that, The target spectral value includes the center wavelength and bandwidth of the light illuminating the wafer under test; And / or, the spectral threshold includes a center wavelength threshold and a bandwidth threshold, wherein the center wavelength threshold is 0.2 nm and the bandwidth threshold is 0.3 nm.

7. A wafer bonding apparatus, characterized in that, The wafer bonding apparatus includes a full-band light source, a filter wheel, a drive unit, a spectral detection unit, and a camera. A filter is mounted on the filter wheel. The full-band light source emits illumination light to the filter, which receives and filters the illumination light to form band light. This band light illuminates the wafer. The camera captures image information of the wafer. The drive unit is connected to the filter wheel. The spectral detection unit detects the current optical parameters of the area of ​​the wafer illuminated by the band light. The wafer bonding apparatus further includes an acquisition module, an adjustment module, and an image module, wherein: The acquisition module is used to acquire the current optical parameters and target optical parameters of the wafer under test. The current optical parameters include the current spectral value, and the target optical parameters include the target spectral value of the wafer under test. The target spectral value and the current spectral value are compared to obtain the spectral difference. The adjustment module is used to obtain a spectral threshold. When the spectral difference is greater than the spectral threshold, it controls the driving component to drive the filter wheel to adjust the current spectral value by switching the area of ​​the illumination light filtered by the filter on the filter wheel, and makes the spectral difference less than or equal to the spectral threshold. The image module is used to control the camera to acquire image information of the wafer under test when the spectral difference is less than or equal to the spectral threshold.

8. The wafer bonding apparatus according to claim 7, characterized in that, The wafer bonding apparatus further includes a reflector and a beam splitter. The reflector is used to reflect the light of the specified wavelength to the beam splitter, and the beam splitter is used to reflect the light of the specified wavelength onto the wafer to form image light. The image light passes through the beam splitter and is transmitted to the camera.

9. The wafer bonding apparatus according to claim 7, characterized in that, The full-band light source is a laser-driven light source, and the illumination light emitted by the full-band light source has a wavelength range of 190nm-1700nm. And / or, the number of the filters is multiple, and the multiple filters are used to filter light of different wavelengths. The wafer bonding device also includes a filter wheel, and the multiple filters are spaced apart along the circumference of the filter wheel.

10. The wafer bonding apparatus according to claim 7, characterized in that, The wafer bonding apparatus further includes an intensity adjustment unit and / or a spot shaping and homogenizing unit. The spot shaping and homogenizing unit is used to collimate and homogenize the illumination light, and the intensity adjustment unit is used to adjust the intensity of the illumination light and emit the illumination light.

11. The wafer bonding apparatus according to claim 10, characterized in that, The light spot shaping and homogenization unit includes a microlens array and a field lens. The microlens array is disposed in the output light path of the full-band light source. The microlens array receives the illumination light and outputs it to the field lens. The field lens receives and outputs the illumination light. And / or, the light intensity adjustment unit includes a variable aperture for receiving the illumination light, adjusting the intensity of the illumination light, and emitting the illumination light to the filter.

12. A computer-readable storage medium, characterized in that, The medium stores a program that can be loaded by a processor and executed as the wafer bonding light source control method as described in any one of claims 1 to 6.

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