Ultrasonic detection equipment, method and device, electronic equipment and medium

Abstract

The invention provides ultrasonic detection equipment, method and device, electronic equipment and a medium. The method comprises the following steps: acquiring first ultrasonic signals acquired by a plurality of ultrasonic transducers; performing Hilbert transform on the first ultrasonic signal to obtain a transformed second ultrasonic signal; finding a surface wave based on a comparison result of the second ultrasonic signal and a surface wave threshold value; comparing a waveform in a preset time after the surface wave in the second ultrasonic signal with a bonding layer threshold value to find a bonding layer waveform; and determining whether the bonding layer has a layering defect or not based on the amplitude of the bonding layer waveform. According to the method, the problems that noisy points exist on the image and layering defects are omitted can be avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of ultrasonic detection, and particularly to an ultrasonic detection device, method, apparatus, electronic device and medium. Background Art

[0002] Bonded wafers are a key application process for high-end semiconductor devices. This process is highly difficult, and process defects such as bubbles and impurities are likely to appear in the bonding layer, which affect the key performance of the device. These defects are inside the wafer and are difficult to observe by means of optical imaging and the like. Detection methods such as X-Ray are difficult to balance detection efficiency and accuracy. A semiconductor bonding ultrasonic detection device uses a high-frequency ultrasonic transducer to image the internal defects of the wafer, and then uses an intelligent analysis system and the like to realize the automatic identification and size classification of the internal defects of the wafer. It can be used for product quality monitoring and process analysis in the wafer bonding stage to achieve the purpose of improving quality and efficiency. It is a detection device developed for the wafer bonding production stage.

[0003] In this application, a high-frequency ultrasonic detection system is used to collect signals at each position on the wafer. The collected signals include surface wave signals (signals reflected back when ultrasonic waves are emitted to the wafer surface) and bonding layer signals (signals reflected back when ultrasonic waves are emitted to the bonding layer). Under normal circumstances, waveforms that meet expectations can be captured for both the surface wave and the bonding layer signal. However, when there are bubbles in the water flow, or when there are occasional phenomena such as protrusions, depressions, and dirt on the surface, there will be a phenomenon that the surface wave cannot be captured or is captured inaccurately, and the bonding layer waveform cannot be captured or is captured inaccurately. This problem will result in black or white noise points on the image and the possibility of missing delamination defects. Summary of the Invention

[0004] The present invention provides an ultrasonic detection device, method, apparatus, electronic device and medium, which can avoid the problems of noise points on the image and missing delamination defects.

[0005] According to one aspect of the present invention, there is provided an ultrasonic data analysis method, including: Obtaining first ultrasonic signals collected by a plurality of ultrasonic transducers; Performing Hilbert transform on the first ultrasonic signals to obtain second ultrasonic signals after transformation; Finding the surface wave based on the comparison result between the second ultrasonic signals and the surface wave threshold value; comparing the waveforms within a preset time after the surface wave in the second ultrasonic signals with the bonding layer threshold value to find the bonding layer waveform; Determining whether there is a delamination defect in the bonding layer based on the amplitude of the bonding layer waveform.

[0006] Optionally, the finding the surface wave based on the comparison result between the second ultrasonic signals and the surface wave threshold value includes: Compare the second ultrasonic signal with the surface wave threshold value, and determine the waveform with the peak value within the range of the surface wave threshold value in the second ultrasonic signal as the surface wave.

[0007] Optionally, finding the surface wave based on the comparison result between the second ultrasonic signal and the surface wave threshold value includes: Determine the waveform with the peak amplitude of the second ultrasonic signal greater than the surface wave threshold value for the first time as the surface wave.

[0008] Optionally, after determining whether there is a delamination defect in the bonding layer based on the amplitude of the bonding layer waveform, it further includes: Obtain the bonding layer waveforms corresponding to the first ultrasonic signals collected by multiple ultrasonic transducers, as well as the position information of the first ultrasonic signals corresponding to the wafer, to obtain the bonding layer waveforms corresponding to each position on the wafer; Convert the amplitude values of the bonding layer waveforms corresponding to each position on the wafer into the gray values of each pixel point, and then obtain a complete first wafer gray image, where the first wafer gray image is used to reflect the distribution of various defects on the wafer.

[0009] Optionally, it further includes: S101. Calculate the difference between each pixel point in the second wafer gray image and the first neighboring pixel points; the first neighboring pixel points are the pixel points within the first preset range of a pixel point; each pixel point in the second wafer gray image represents the amplitude of the surface wave collected at the corresponding position on the wafer; S102. Take the pixel points with the difference exceeding the preset threshold as the pixel points to be corrected, add the pixel points to be corrected to the set of pixel points to be corrected, and take other pixel points as the neighboring reference points; S103. Determine the surface wave position of the pixel point to be corrected based on the surface wave positions of the neighboring pixel points of the pixel point to be corrected, re-find the bonding layer waveform of the pixel point to be corrected, and take the pixel points converted from the bonding layer waveform of the pixel point to be corrected as the neighboring reference points; S104. Repeat step S103 until all the points in the set of pixel points to be corrected are searched; S105. If there are still pixel points to be corrected that cannot be searched successfully in the set of pixel points to be corrected, then use the second neighboring pixel points within the second preset range of the pixel points to be corrected as the neighboring reference points; the second preset range is greater than the first preset range; S106. Determine the surface wave position of the pixel to be corrected based on the surface wave positions of the neighboring pixels of the pixel to be corrected, re-search for the bonding layer waveform of the pixel to be corrected, and use the pixel converted from the bonding layer waveform of the pixel to be corrected as the neighborhood reference point until all the points in the set to be corrected have been searched; S107. When there is no pixel to be corrected in the set to be corrected that fails to be searched successfully, redraw the grayscale image of the second wafer based on the pixels converted from the corrected bonding layer waveform.

[0010] According to one aspect of the present invention, there is provided an ultrasonic detection device capable of implementing the ultrasonic data analysis method described in any embodiment of the present invention, including: a signal collector, a signal transceiver electrically connected to the signal collector, a motion device, and a plurality of ultrasonic transducers provided on the motion device; the motion device includes a motion axis and a motion controller; the ultrasonic transducers are communicatively connected to the signal transceiver; The motion controller controls the motion axis to move to a preset position and sends a trigger signal to the signal transceiver and the signal collector; so that the signals received at the signal transceiver and the signal collector ends are synchronized; After receiving the trigger signal, the signal transceiver activates the ultrasonic transducers to emit ultrasonic signals to the wafer, receives the echo signals collected by the ultrasonic transducers, and then transmits the echo signals to the signal collector; The motion axis moves under control and is used to drive the ultrasonic transducers to move horizontally above the wafer.

[0011] Optionally, it further includes a waterway system, and the waterway system provides a coupling medium for the ultrasonic transducers, so that the ultrasonic signals emitted by the ultrasonic transducers are transmitted from the ultrasonic transducers to the wafer surface and then enter the wafer interior.

[0012] According to another aspect of the present invention, there is provided an ultrasonic data analysis device, including: An acquisition unit for acquiring first ultrasonic signals collected by a plurality of ultrasonic transducers; A transformation unit for performing Hilbert transformation on the first ultrasonic signals to obtain transformed second ultrasonic signals; A waveform confirmation unit for finding surface waves based on the comparison result between the second ultrasonic signals and the surface wave threshold value; comparing the waveforms within a preset time after the surface waves in the second ultrasonic signals with the bonding layer threshold value to find the bonding layer waveform; A defect confirmation unit for determining whether there is a delamination defect in the bonding layer based on the amplitude of the bonding layer waveform.

[0013] According to another aspect of the present invention, there is provided an electronic device, which includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein, the memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor to enable the at least one processor to execute the ultrasonic data analysis method according to any embodiment of the present invention.

[0014] According to another aspect of the present invention, there is provided a computer-readable storage medium storing computer instructions for causing a processor to implement the ultrasonic data analysis method according to any embodiment of the present invention when executed.

[0015] The technical solution of the embodiment of the present invention is as follows: by acquiring first ultrasonic signals collected by a plurality of ultrasonic transducers; performing Hilbert transform on the first ultrasonic signals to obtain second ultrasonic signals after transformation; finding surface waves based on the comparison result between the second ultrasonic signals and the surface wave threshold value; comparing the waveforms within a preset time after the surface waves in the second ultrasonic signals with the bonding layer threshold value to find the bonding layer waveforms; and determining whether there are delamination defects in the bonding layer based on the amplitudes of the bonding layer waveforms, thereby solving the problems of noise points on the image and the possibility of missing delamination defects.

[0016] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present invention, nor is it used to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts.

[0018] Figure 1 is a structural diagram of an ultrasonic detection device according to Embodiment 1 of the present invention; Figure 2 is a schematic diagram of the overall structure of the detection device in an embodiment; Figure 3 is a schematic diagram of performing Hilbert transform on waveforms; Figure 4 is a flowchart of an ultrasonic data analysis method according to Embodiment 2 of the present invention; Figure 5Schematic diagram of the waveform of the echo signal in an embodiment of the present invention; Figure 6 Schematic diagram of the waveform after performing Hilbert transform on the echo signal in an embodiment of the present invention; Figure 7 Schematic diagram of the partial imaging of the wafer detected in an embodiment of the present invention; Figure 8 Schematic diagram of the waveform when there is no defect in the bonding layer in an embodiment of the present invention; Figure 9 Schematic diagram of the waveform when there is a defect in the bonding layer in an embodiment of the present invention; Figure 10 The first wafer grayscale image obtained by converting the bonding layer signal into grayscale values in an embodiment of the present invention; Figure 11 Flowchart of the intelligent error correction method in an embodiment of the present invention; Figure 12 Structural diagram of an ultrasonic data analysis device provided in Embodiment 3 of the present invention; Figure 13 Schematic structural diagram of an electronic device for implementing the ultrasonic data analysis method of the present invention. Detailed implementation manners

[0019] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0020] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the accompanying drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0021] Bonded wafers are a key application process for high-end semiconductor devices. This process is highly difficult, and process defects such as bubbles and impurities are likely to appear in the bonding layer, which can affect the key performance of the devices. These defects are inside the wafers and are difficult to observe by means of optical imaging and so on. It is also difficult to balance detection efficiency and accuracy by means of detection methods such as X-Ray. The semiconductor bonding ultrasonic detection equipment uses high-frequency ultrasonic transducers to image the internal defects of wafers, and then uses an intelligent analysis system, etc. to realize the automatic identification and size classification of the internal defects of wafers. It can be used for product quality monitoring and process analysis in the wafer bonding process to achieve the purpose of improving quality and increasing efficiency. It is a detection equipment developed for the wafer bonding production stage. The equipment adopted in this application is a high-frequency ultrasonic detection system.

[0022] The requirements for the ultrasonic detection system are as follows: 1. Scanning accuracy: The highest scanning accuracy is 50um, and the scanning accuracy can be set. 2. Efficiency: 6 pieces per hour at 50*50um (interlaced interpolation), 12 pieces per hour at 100*100um (interlaced scanning); 3. Product specifications: 12-inch bonded wafers, made of silicon, with a product thickness of 1600um and a thickness from the layer to be detected to the wafer surface of 775um; 4. Scanning methods: A-Scan, C-Scan, X-Scan, TOF-Scan, Z-Scan.

[0023] Embodiment 1 Figure 1 A structural diagram of an ultrasonic detection equipment is provided for Embodiment 1 of the present invention. As Figure 1 shown, the equipment includes: a signal collector, a signal transceiver electrically connected to the signal collector, a motion device, and a plurality of ultrasonic transducers arranged on the motion device; the motion device includes a motion axis and a motion controller; the ultrasonic transducers are communicatively connected to the signal transceiver; The motion controller controls the motion axis to move to a preset position, and sends a trigger signal to the signal transceiver and the signal collector; so that the signals received at the signal transceiver and the signal collector ends are synchronized; After receiving the trigger signal, the signal transceiver activates the ultrasonic transducers to emit ultrasonic signals to the wafer, receives the echo signals collected by the ultrasonic transducers, and then transmits the echo signals to the signal collector; The motion axis moves under control, and is used to drive the ultrasonic transducers to move horizontally above the wafer.

[0024] It should be noted that the motion controller is used to control the motion axis to move to a preset position, and then send a trigger signal to the signal transceiver so that the ultrasonic transducer on the motion device can move to a specified position above the wafer, and control the signal transceiver to excite the signal, so that the ultrasonic probe sends an ultrasonic signal to a specified position on the wafer and injects it into the wafer; and receives the echo signal of the ultrasonic signal, which is received by the signal transceiver and then transmitted to the signal collector. After the terminal device receives the collected echo signal, it can generate an acoustic image of the specified position. Among them, the motion device includes a motion axis and a motion controller, and the motion control signal sent by the motion controller controls the motion axis to move.

[0025] It should be noted that in the present application, the motion controller can send a trigger signal to the signal transceiver and the signal collector at the same time to ensure the synchronization and accuracy of the signals received by the signal transceiver and the signal collector.

[0026] It also includes: a water channel system, which provides a coupling medium for the ultrasonic transducer, so that the ultrasonic signal emitted by the ultrasonic transducer is transmitted from the ultrasonic transducer to the surface of the wafer and then enters the interior of the wafer.

[0027] It should be noted that the water system can continuously flow water to provide an ultrasonic coupling medium for ultrasonic waves, which can enable ultrasonic waves to be efficiently transmitted from the ultrasonic transducer to the surface of the wafer and then enter the inside of the wafer to ensure the quality and strength of the detection signal. In addition, there are differences in the acoustic impedance of the ultrasonic probe water and the wafer. A suitable water system can adjust the transition of the acoustic impedance, reduce the reflection of ultrasonic waves at the interface, and allow more ultrasonic energy to enter the wafer, thereby improving the sensitivity and accuracy of the detection. In addition, when the ultrasonic imaging device is working, components such as the ultrasonic transducer will generate heat. Long-term operation may cause excessive temperature, affecting the performance and life of the equipment. The water in the water system can take away this heat through circulation, play a role in cooling and heat dissipation, and maintain the stable operation of the equipment. During the detection process, the water in the water system can also rinse the surface of the wafer to remove dust, impurities and other pollutants on the surface to prevent these pollutants from affecting the transmission and reflection of ultrasonic waves, thereby improving the accuracy of the detection results, and also avoiding damage to the ultrasonic transducer caused by pollutants.

[0028] It also includes an air knife, which is used to quickly dry the moisture on the surface of the wafer by blowing out high-speed air flow after the detection is completed, so as to keep the wafer dry. It can also blow away impurities such as tiny particles and dust on the surface of the wafer, further improving the cleanliness of the wafer surface and ensuring the accuracy of detection and the quality of the wafer. In addition, the air flow blown out by the air knife can generate a certain pressure on the wafer, playing a role in assisting positioning and fixing the wafer, ensuring that the wafer maintains a stable position during the detection process, and improving the accuracy and repeatability of detection. Especially for some thin and light wafers, the air flow of the air knife can provide additional supporting force to prevent the wafer from shaking or shifting during the detection process.

[0029] In the embodiment as Figure 2 shown, the ultrasonic data acquisition device includes a dryer, a wafer loader (Loadport), an edge finder, a wafer spin dryer, a wafer manipulator, and a wafer detection platform.

[0030] a. The wafer loader is used to place the wafer cassette. b. The upper arm of the wafer manipulator takes the first wafer from the cassette and places it on the edge finder for edge finding, rotation correction, and center correction. c. The upper arm of the manipulator takes the wafer from the edge finder and places it on the wafer detection platform and sucks vacuum. d. The motion control platform starts to move, and the probe starts to collect ultrasonic signals. e. The manipulator takes the second wafer from the cassette and places it on the edge finder for edge finding, rotation correction, and center correction, then takes the wafer from the edge finder and places it on the wafer detection platform and sucks vacuum; and waits for the ultrasonic signal collection process of the first wafer to end. f. After collecting the signals of the entire wafer, the hair dryer blows away most of the water stains on the wafer surface. g. The wafer detection platform (Chuck) releases the vacuum, and the lower arm of the manipulator takes the wafer from the wafer detection platform (Chuck) and puts a new wafer into the upper arm. h. The manipulator places the wafer on the spin dryer to make the wafer dry more thoroughly. i. The robotic arm goes deep into the dryer for drying. j. The upper arm of the robotic arm takes the dried wafer from the spin dryer and places it on the edge finder for edge finding. k. After the edge finding is completed, the upper arm of the manipulator takes out the wafer and puts it back into the wafer loader. l. The manipulator starts the processes a, b, and c of the third wafer and continues to cycle until all the wafers in the wafer loader are detected.

[0031] In one embodiment, for different usage scenarios, corresponding probes need to be selected specifically. The main considerations are as follows: 1. The thickness of the sample, and the corresponding probe parameter is the probe focal length; 2. Lateral resolution, mainly examining the resonant frequency of the probe and the beam width in the focal area; 3. Axial resolution, the higher the axial resolution requirement, the shorter the pulse duration, the higher the probe frequency, and the greater the damping required.

[0032] a. Frequency: Generally, the higher the frequency of the probe, the higher the measurable accuracy. The probe frequency generally refers to the frequency when the object to be measured is closest to the probe in water. Since ultrasonic waves attenuate during propagation in the medium, this nominal frequency is not the actual operating frequency. In this scenario, a 100 MHz probe is selected to detect defects of 25 um or more.

[0033] b. Focal length - in water: The nominal focal length generally refers to the optimal working height of the probe's detection performance in water (the focal length of the probe selected for this system is 12.7 mm). For different probes of the same model, there are slight differences in the focal length. The test method is to move the probe to a position at the nominal focal length from the surface of the object to be measured, and adjust the Z-axis height in steps of 0.1 mm until the intensity of the echo from the surface of the object to be measured (hereinafter collectively referred to as the surface wave) reaches the maximum. At this time, the Z-axis height is the focal length of the probe in water.

[0034] c. Focal length - for the object to be measured: The sound speed in the wafer to be measured is different from that in water. During the propagation of ultrasonic waves, refraction occurs at the water and wafer surfaces. The focal length in the wafer is less than that in water. To determine the focal length in the object to be measured, the probe needs to be moved downward along the Z-axis so that the amplitude of the echo signal at the surface to be measured and the bonding layer of the wafer is the largest. In this application scenario, the probe needs to be lowered by 7 - 8 mm, and the amplitude of the echo signal of the bonding layer is the largest. This is the focal length used for the object to be measured.

[0035] d. Focal length range: The evaluation method for the focal length range is to move the probe's Z-axis up and down based on the focal length. The Z-axis range where the amplitude of the echo signal is greater than half of the amplitude at the focal length is the focal length range. In this scenario, the focal length range is approximately 2 mm.

[0036] e. Resonant frequency: As mentioned in a, the nominal frequency is not the operating frequency. Collect the A-wave at the focus and perform Fourier transform. The horizontal axis frequency corresponding to the point with the largest amplitude (vertical axis) is the resonant frequency, which is also the maximum value of the probe's operating frequency (this probe is approximately 62 MHz), and the corresponding maximum resolution is between 20 um and 30 um.

[0037] f. -6dB Bandwidth: The resolution bandwidth represents the ability to distinguish two different frequency signals in the spectrum. At the focus, the industry standard selects the frequency range corresponding to the intensity within -6dB of the resonant frequency amplitude intensity as the resolution bandwidth. In an actual example, the resonant frequency intensity is 66dB, -6dB is 60dB, the corresponding frequency range is from 47.8MHz to 81MHz, and the -6dB bandwidth is 33.2MHz.

[0038] g. Pulse Width: The pulse width is determined by the bandwidth. The pulse width is generally several tens of ns. The narrower the pulse width, the higher the resolution in the Z-axis direction. In this scenario, it is required that the pulse width is less than 100ns, and the Z-axis resolution accuracy is 75um, meeting the Z-axis resolution requirements of wafers with a thickness of 1200 - 1800um (the height from the wafer surface to the bonding layer is 600 - 900um). In the industry, the -20dB is generally used as the evaluation standard for the pulse width. As Figure 3 shown, after the waveform undergoes Hilbert transform, the horizontal axis is the time axis, the vertical axis amplitude is normalized between 0 - 1, -20dB is the position of 0.1 on the vertical axis, and the corresponding horizontal axis -20dB bandwidth is approximately 58ns.

[0039] In one embodiment, during the machine setup: (Here, a 12-inch wafer, 300mm * 300mm, is taken as an example): a. Set the wafer size; b. Set the wafer orientation, that is, the orientation of the notch on the wafer, and set the wafer rotation angle on the edge finder; c. Set the position of the wafer on the wafer stage and calibrate the pick-and-place position of the robot; d. Scan a 350 * 350mm acquisition area. Each probe acquires a distance of 87.5mm in the Y direction and images; e. Calibrate the position deviation between each probe according to the interleaving range of the image; f. Scan the image again to verify that the wafer images completely overlap into a standard circle; g. Confirm the minimum scan area (305mm * 305mm) according to the position of the wafer in the image; h. After the above steps are completed, it can meet the requirement of scanning the complete wafer area within the minimum scan range.

[0040] In one embodiment, the debugging of the ultrasonic system parameters includes: The ultrasonic system mainly consists of a trigger (motion controller), an ultrasonic pulse transceiver, a probe, an acquisition card, and related cables. Each component includes: a. Trigger: The trigger is integrated in the motion controller. The trigger mainly debugs two aspects of parameters: trigger interval (trigger frequency) and trigger voltage. The trigger interval needs to match the scanning accuracy, and the trigger voltage needs to match the minimum voltage of 3.3V for the ultrasonic pulse transceiver to work. For example, if the scanning accuracy is 100um * 100um, then it is triggered once when the X-axis moves 100um, and the Y-axis moves 100um after the X-axis has moved one row. The trigger voltage is determined by the parameters of the ultrasonic pulse transceiver; b. Ultrasonic pulse transceiver: The ultrasonic pulse transceiver has the following parameters to be set: (1) Working mode: Transmission or echo mode. Here, the echo mode is used; (2) Gain: The signal amplification factor. This parameter needs to be used in combination with the range parameter of the acquisition card to make the intensity of the signal to be measured basically close to the full scale; (3) Low / High pass filter: Set the range of the echo frequency to be collected. In this project, 30 - 300MHz is used, mainly to filter out low-frequency components and prevent noise; (4) Trigger source: External, triggered by the trigger; (5) Voltage: 330 - 380V. By default, the low voltage of 330V is used to extend the life of the probe; (6) Energy: low / high. By default, low is used to extend the life of the probe; (7) Impedance: 25 - 100 Ohms. Selected according to the impedance of the probe. Here, 100 Ohms is selected; c. Acquisition card: The sampling frequency matches more than five times the signal frequency of the probe. In this project, a sampling frequency of 1GHz is used; Sampling length is 1024 or 2048, and different parameters are set according to different surface warping degrees. The higher the warping degree, the longer the sampling length; Range: in millivolts, and it needs to be used in combination with the gain parameter of the ultrasonic pulse transceiver to make the amplitudes of the surface wave and the bonding layer echo as large as possible without exceeding the range. In this project, the acquisition card with a range of 200mV is used in combination with the pulse transceiver with a gain of 40dB; d. Probe: The probe needs to adjust the focal length to make the test plane in the best imaging range, that is, the signal intensity (A-wave amplitude) of the profile to be detected is the largest.

[0041] It should be noted that under normal circumstances, waveforms that meet expectations can be captured for both the surface wave and the bonding layer. However, when there are bubbles in the water flow, or there are occasional phenomena such as protrusions, depressions, and dirt on the surface, there may be a situation where the surface wave cannot be captured or is captured inaccurately, and the bonding layer waveform cannot be captured or is captured inaccurately. This problem will cause black or white noise points to appear in the image, as well as the possibility of missing delamination defects. To address these two types of problems, two coping methods, surface tracking and intelligent error, have been developed.

[0042] If a relatively small threshold range is used to search for surface waves, the search for the position of the surface waves will be restricted. In the case where the wafer has a certain warpage or the ultrasonic waves fluctuate, the surface waves cannot be found. Using a larger threshold range may cause the reflected waves of the bonding layer or other interfering clutter to be misdetected as surface waves, resulting in false detection or missed detection.

[0043] Embodiment 2 To solve the above problems, the present application provides an ultrasonic data analysis method, as Figure 4 shown, the method includes: S10. Obtain first ultrasonic signals collected by a plurality of ultrasonic transducers. It should be noted that the first ultrasonic signal is the echo signal collected by the ultrasonic transducer from a position on the wafer. The echo signal includes a surface wave signal and a bonding layer signal. Among them, since the surface wave is the echo signal of the ultrasonic wave emitted to the wafer surface, and the bonding layer signal is the echo signal of the ultrasonic wave passing through the wafer surface and entering the bonding layer in the wafer, the signal transceiver will first receive the surface wave signal and then receive the bonding layer signal. Moreover, each unit position on the wafer corresponds to a first ultrasonic signal, that is, the first ultrasonic signals collected by a plurality of ultrasonic transducers can detect the bonding state of each position on the wafer. The unit position can be set by the user, and each unit position can correspond to a pixel point.

[0044] S20. Perform Hilbert transform on the first ultrasonic signal to obtain a transformed second ultrasonic signal.

[0045] S30. Find the surface wave based on the comparison result between the second ultrasonic signal and the surface wave threshold value; compare the waveform within a preset time after the surface wave in the second ultrasonic signal with the bonding layer threshold value to find the bonding layer waveform. It should be noted that since there is a time sequence relationship between the surface wave and the bonding layer waveform, the surface wave is in the front and the bonding layer waveform is in the back, and the surface wave usually has a larger amplitude, while the bonding layer waveform usually has a smaller amplitude. Therefore, a surface wave threshold value can be set to determine the surface wave, and the waveform that appears after the surface wave is compared with the bonding layer threshold value to determine the bonding layer waveform.

[0046] S40. Determine whether there is a delamination defect in the bonding layer based on the amplitude of the bonding layer waveform.

[0047] Usually, when the peak value of the bonding layer waveform is large, it indicates that there may be a defect in the bonding situation at that position on the wafer.

[0048] In one embodiment, after the ultrasonic signal acquisition is completed, the process of analyzing the data includes: a. Converting ultrasonic signals into images: For the ultrasonic signals collected by the ultrasonic transducer, the acquired ultrasonic waveform data is analyzed at a certain step size (50um or 100um). The steps are as follows: 1. The waveform of a single collected position point is generally 8-bit data (or 12-bit or 16-bit, depending on the sampling length of the acquisition card) with a length of 1024 sampling points or 2048 sampling points; As Figure 5 shown, the ultrasonic echo with a single-point length of 2048 is collected, the sampling frequency is 1.25 GHz. In the unprocessed ultrasonic waveform diagram, the horizontal axis represents the time axis, the vertical axis represents the amplitude, and each point in the signal represents the echo signal received by the probe at a specific time; 2. Perform Hilbert transform on the single collected point and normalize all amplitudes to the positive axis; The waveform diagram after Hilbert transform is as Figure 6 shown. The yellow waveform is the waveform after Hilbert transform; 3. Set a data threshold to identify surface waves (surface waves refer to the waveform amplitude returned when ultrasonic waves contact the wafer surface); As Figure 6 shown, the surface wave threshold amplitude is 100 - 1100um. The X-axis value corresponding to the green vertical line is the 900th sampling point, which is the position of the surface wave peak. The green vertical line is the maximum signal intensity, and the corresponding Y-axis value is the surface wave amplitude. At this time, the <position, amplitude> numerical coordinates corresponding to the surface wave peak are <900, 84>; 4. Set a data threshold within a certain length after the surface wave (i.e., the ultrasonic wave returned by the bonding layer to be detected) to detect whether there is a delamination defect in the bonding layer to be detected. Generally, if there is no defect, the waveform amplitude returned by the bonding layer data threshold is small. If there is a delamination defect, the waveform amplitude returned by the bonding layer data threshold is large. Record the maximum amplitude captured by the bonding layer data threshold at this point; It should be noted that since the surface wave is the echo signal of the ultrasonic wave emitted to the wafer surface, and the bonding layer signal is the echo signal of the ultrasonic wave passing through the wafer surface and entering the bonding layer in the wafer, therefore, the signal transceiver will first receive the surface wave signal and then receive the echo signal of the bonding layer; Figure 7 For local imaging of the wafer to be detected, white dots represent air bubble defects in the bonding layer, and black dots represent normal. As Figure 9 is the waveform of the white dot, Figure 8 is the waveform of the black dot. The white dot waveform obviously has a larger amplitude at the red vertical line, which reflects that the peak value of the bonding layer waveform is larger, that is, there is a defect in the bonding layer waveform at this position; the black dot waveform has a smaller amplitude at the red line, indicating that there is no defect in the bonding layer; 5. Normalize the bond layer data in the echo signal obtained in step 4 within the range of 0 - 255 to obtain the signal intensity of the bond layer; 6. Plot the signal intensity obtained in 5 on the image. At this time, this data contains three pieces of information: the horizontal and vertical coordinates x, y on the plane, and the signal intensity (i.e., amplitude) d of this point. Plot the information of this point on a picture representing the wafer, and plot the gray level of the pixel at the coordinate (x, y) on the picture as d; 7. After the signal processing of all acquisition points is completed, a complete gray - scale image of the bond layer of the wafer can be obtained, specifically as Figure 10 shown.

[0049] The image can be analyzed. For example, extract the circular area within the white border from the image obtained in step 7 as the effective area to be detected. Extract the white - dot area within the effective area according to a certain threshold, and calculate the pixel area of each white dot (taking Figure 10 as an example, each pixel represents 100um). Classify the white - dot area into different - sized defect levels according to the defect classification setting (for example, the defects are divided into 100 - 300um, 300um - 500um, greater than 500um).

[0050] In one embodiment, finding the surface wave based on the comparison result between the second ultrasonic signal and the surface - wave threshold value includes: Compare the second ultrasonic signal with the surface - wave threshold value, and determine the waveform whose peak value in the second ultrasonic signal is within the surface - wave threshold value range as the surface wave.

[0051] In this embodiment, the second ultrasonic signal after the conversion of the echo signal can be directly compared with the surface - wave threshold value, and the waveform whose peak value in the second ultrasonic signal is within the surface - wave threshold value range is determined as the surface wave. Thus, the surface wave can be quickly detected.

[0052] In one embodiment, finding the surface wave based on the comparison result between the second ultrasonic signal and the surface - wave threshold value may further include: Determine the waveform whose peak - amplitude of the first - appearing wave in the second ultrasonic signal is greater than the surface - wave threshold value as the surface wave.

[0053] In this embodiment, the waveform whose peak - amplitude of the first - appearing wave in the second ultrasonic signal is greater than the surface - wave threshold value can be directly determined as the surface wave. This solution can stably obtain the correct surface wave without being affected by wafer warping and other clutter.

[0054] In one embodiment, after determining whether there is a delamination defect in the bond layer based on the amplitude of the bond - layer waveform, it further includes: Obtain the bond layer waveforms corresponding to the first ultrasonic signals collected by the multiple ultrasonic transducers, as well as the position information of the first ultrasonic signals corresponding to the positions on the wafer, so as to obtain the bond layer waveforms corresponding to each position on the wafer. Convert the amplitude values of the bond layer waveforms corresponding to each position on the wafer into the gray values of each pixel point, and then obtain a complete first wafer gray image, where the first wafer gray image is used to reflect the distribution of various defects on the wafer.

[0055] It should be noted that the amplitude values of the bond layer waveforms can be normalized according to the range of the gray value space 0-255, and the amplitude values of the bond layer waveforms collected at each unit position on the wafer are converted into gray values, and then a first wafer gray image reflecting the distribution of various defects on the wafer can be obtained.

[0056] In an embodiment, as Figure 11 shown in the intelligent error correction method Figure 11 includes: S101. Calculate the difference between each pixel point in the second wafer gray image and the first neighboring pixel points; the first neighboring pixel points are the pixel points within the first preset range of a pixel point; each pixel point in the second wafer gray image represents the amplitude of the surface wave collected at the corresponding position on the wafer. S102. Take the pixel points with differences exceeding the preset threshold as the pixel points to be corrected, add the pixel points to be corrected to the set of points to be corrected, and take other pixel points as neighboring reference points. S103. Determine the surface wave position of the pixel point to be corrected based on the surface wave positions corresponding to the neighboring pixel points of the pixel point to be corrected, re-search for the bond layer waveform of the pixel point to be corrected, and take the pixel point converted from the bond layer waveform of the pixel point to be corrected as a neighboring reference point. S104. Repeat step S103 until all the points in the set of points to be corrected have been searched. S105. If there are still pixel points to be corrected that have not been successfully searched in the set of points to be corrected, then use the second neighboring pixel points within the second preset range of the pixel points to be corrected as neighboring reference points; the second preset range is larger than the first preset range. S106. Determine the surface wave position of the pixel point to be corrected based on the surface wave positions corresponding to the neighboring pixel points of the pixel point to be corrected, re-search for the bond layer waveform of the pixel point to be corrected, and take the pixel point converted from the bond layer waveform of the pixel point to be corrected as a neighboring reference point until all the points in the set of points to be corrected have been searched. S107. When there are no pixel points to be corrected that have not been successfully searched in the set of points to be corrected, redraw the second wafer gray image based on the pixel points converted from the corrected bond layer waveforms.

[0057] It should be noted that during the ultrasonic scanning process, tens of millions of points may need to be collected. During the collection process, due to small bubbles in the water flow, free impurities, bumps on the wafer surface, Hex (hexagonal silicon), etc., the surface waves may become unstable or the signals may be too weak to be recognized. In such cases, noise may be generated, thus interfering with the stability of the detection results. Based on the high standard requirements for the flatness of the wafer (flatness ≤ ±20um), in a local area, all surface waves should appear at close positions. If there are surface waves that appear outside the range, it proves that there is interference caused by the above reasons here, resulting in inaccurate surface wave search. Inaccurate surface wave search will cause inaccurate search for the bonding layer, thus introducing noise. Therefore, pixel points with a difference exceeding the preset threshold may be inaccurate search pixel points. Therefore, the pixel points obtained by converting the waveform of the bonding layer at this point need to be used as neighborhood reference points for re-searching.

[0058] In this embodiment, the method of determining the difference between a pixel point and its neighborhood pixel points can be used to determine whether the pixel point needs to be corrected. Then, the pixel points at all unit positions of the wafer are calculated to find the pixel points that need to be corrected and correct them, so as to output the corrected second wafer grayscale image. After intelligent error correction, some noise points caused by abnormal conditions can be excluded.

[0059] Embodiment 3 Figure 12 An ultrasonic data analysis device provided in Embodiment 3 of the present invention, as Figure 12 shown, the device includes: An acquisition unit 110, configured to acquire first ultrasonic signals collected by a plurality of ultrasonic transducers; A transformation unit 120, configured to perform Hilbert transformation on the first ultrasonic signal to obtain a transformed second ultrasonic signal; A waveform confirmation unit 130, configured to find surface waves based on the comparison result between the second ultrasonic signal and the surface wave threshold value; compare the waveform within a preset time after the surface wave in the second ultrasonic signal with the bonding layer threshold value to find the bonding layer waveform; A defect confirmation unit 140, configured to determine whether there is a delamination defect in the bonding layer based on the amplitude of the bonding layer waveform.

[0060] The ultrasonic data analysis device provided in the embodiments of the present invention can execute the ultrasonic data analysis method provided in any embodiment of the present invention, and has corresponding functional modules and beneficial effects for executing the method.

[0061] Embodiment 4 Figure 13FIG. shows a schematic structural diagram of an electronic device 10 that can be used to implement an embodiment of the present invention. The electronic device is intended to represent various forms of digital computers, such as, laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as, personal digital processors, cellular phones, smart phones, wearable devices (such as helmets, glasses, watches, etc.) and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present invention described and / or claimed herein.

[0062] As Figure 13 shown, the electronic device 10 includes at least one processor 11, and a memory communicatively connected to the at least one processor 11, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc. The memory stores a computer program executable by the at least one processor. The processor 11 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 12 or the computer program loaded from the storage unit 18 into the random access memory (RAM) 13. In the RAM 13, various programs and data required for the operation of the electronic device 10 can also be stored. The processor 11, the ROM 12, and the RAM 13 are connected to each other through a bus 14. The input / output (I / O) interface 15 is also connected to the bus 14.

[0063] Multiple components in the electronic device 10 are connected to the I / O interface 15, including: an input unit 16, such as a keyboard, a mouse, etc.; an output unit 17, such as various types of displays, speakers, etc.; a storage unit 18, such as a magnetic disk, an optical disk, etc.; and a communication unit 19, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 19 allows the electronic device 10 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0064] The processor 11 can be various general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of the processor 11 include but are not limited to a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any appropriate processor, controller, microcontroller, etc. The processor 11 executes the various methods and processes described above, such as a method for ultrasonic data analysis.

[0065] In some embodiments, a method for ultrasonic data analysis can be implemented as a computer program tangibly embodied in a computer-readable storage medium, such as storage unit 18. In some embodiments, part or all of the computer program can be loaded and / or installed onto the electronic device 10 via the ROM 12 and / or the communication unit 19. When the computer program is loaded into the RAM 13 and executed by the processor 11, one or more steps of the ultrasonic data analysis method described above can be performed. Alternatively, in other embodiments, the processor 11 can be configured to perform an ultrasonic data analysis method by any other suitable means (e.g., by means of firmware).

[0066] The various embodiments of the systems and techniques described above in this document can be implemented in digital electronic circuitry, integrated circuit systems, field programmable gate arrays (FPGA), application specific integrated circuits (ASIC), application specific standard products (ASSP), systems on a chip (SOC), complex programmable logic devices (CPLD), computer hardware, firmware, software, and / or combinations thereof. These various embodiments can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special-purpose or general-purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit the data and instructions to the storage system, the at least one input device, and the at least one output device.

[0067] The computer programs for implementing the methods of the present invention can be written in any combination of one or more programming languages. These computer programs can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when the computer programs are executed by the processor, the functions / operations specified in the flowcharts and / or block diagrams are implemented. The computer programs can be executed entirely on the machine, partially on the machine, as a stand-alone software package partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0068] In the context of the present invention, a computer-readable storage medium can be a tangible medium that can contain or store a computer program for use by or in connection with an instruction execution system, apparatus, or device. The computer-readable storage medium can include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. Alternatively, the computer-readable storage medium can be a machine-readable signal medium. More specific examples of the machine-readable storage medium would include an electrical connection based on one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0069] To provide for interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and a pointing device (e.g., a mouse or a trackball) by which the user can provide input to the electronic device. Other kinds of devices can also be used to provide for interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including acoustic input, speech input, or tactile input).

[0070] The systems and techniques described herein can be implemented in a computing system that includes backend components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes frontend components (e.g., a user computer having a graphical user interface or a web browser through which the user can interact with an implementation of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: local area network (LAN), wide area network (WAN), blockchain network, and the Internet.

[0071] A computing system may include a client and a server. The client and the server are generally far from each other and usually interact via a communication network. The client-server relationship is created by computer programs that run on respective computers and have a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or a cloud host, which is a host product in the cloud computing service system, and solves the defects of difficult management and weak business scalability existing in traditional physical hosts and VPS services.

[0072] It should be understood that various forms of processes shown above can be used, steps can be reordered, added or deleted. For example, the steps described in the present invention can be executed in parallel, sequentially or in a different order, as long as the desired results of the technical solution of the present invention can be achieved, and no limitation is made herein.

[0073] The above specific embodiments do not constitute a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An ultrasonic data analysis method, characterized in that: include: Acquire first ultrasonic signals collected by multiple ultrasonic transducers; Performing a Hilbert transform on the first ultrasonic signal to obtain a transformed second ultrasonic signal; Find the surface wave based on the comparison result of the second ultrasonic signal and the surface wave threshold value; compare the waveform within a preset time after the surface wave in the second ultrasonic signal with the bonding layer threshold value to find the bonding layer waveform; Whether a delamination defect exists in the bonding layer is determined based on the amplitude of the bonding layer waveform.

2. The ultrasonic data analysis method according to claim 1, characterized in that: The step of finding the surface wave based on the comparison result between the second ultrasonic signal and the surface wave threshold value comprises: The second ultrasonic signal is compared with a surface wave threshold value, and a waveform in the second ultrasonic signal whose peak value is within the range of the surface wave threshold value is determined as a surface wave.

3. The ultrasonic data analysis method according to claim 1, characterized in that: The step of finding the surface wave based on the comparison result between the second ultrasonic signal and the surface wave threshold value comprises: A waveform whose peak amplitude appears for the first time in the second ultrasonic signal is greater than the surface wave threshold value is determined as a surface wave.

4. The ultrasonic data analysis method according to claim 1, characterized in that: After determining whether there is a delamination defect in the bonding layer based on the amplitude of the bonding layer waveform, the method further includes: Acquire the bonding layer waveform corresponding to the first ultrasonic signal collected by the plurality of ultrasonic transducers, and the position information on the wafer corresponding to the first ultrasonic signal, to obtain the bonding layer waveform corresponding to each position on the wafer; The amplitude value of the bonding layer waveform corresponding to each position on the wafer is converted into the grayscale value of each pixel point, thereby obtaining a complete first wafer grayscale image, which is used to reflect the distribution of defects on the wafer.

5. The ultrasonic data analysis method according to claim 4, characterized in that: Also includes: S101, calculating the difference between each pixel in the second wafer grayscale image and the first neighborhood pixel; The first neighborhood pixel point is a pixel point within a first preset range of a pixel point; each pixel point in the second wafer grayscale image represents the amplitude of the surface wave collected at the corresponding position on the wafer; S102, taking the pixel points whose difference exceeds the preset threshold as the pixel points to be corrected, adding the pixel points to be corrected to the set to be corrected, and taking the other pixel points as the neighborhood reference points; S103, determining the surface wave position of the pixel to be corrected based on the surface wave position corresponding to the neighborhood pixel of the pixel to be corrected, re-searching the bonding layer waveform of the pixel to be corrected, and using the pixel point converted from the bonding layer waveform of the pixel to be corrected as the neighborhood reference point; S104, repeat step S103 until all points in the set to be corrected are found; S105, if there are still pixels to be corrected that have not been successfully found in the set to be corrected, a second neighborhood pixel within a second preset range of the pixel to be corrected is used as a neighborhood reference point; The second preset range is larger than the first preset range; S106, determining the surface wave position of the pixel to be corrected based on the surface wave position corresponding to the area pixel of the pixel to be corrected, and re-searching the bonding layer waveform of the pixel to be corrected, and using the pixel point converted from the bonding layer waveform of the pixel to be corrected as the neighborhood reference point, until all the points in the set to be corrected are searched; S107: When the pixel point to be corrected that has not been successfully found does not exist in the set to be corrected, redraw the second wafer grayscale image based on the pixel points converted from the corrected bonding layer waveform.

6. An ultrasonic detection device capable of implementing the ultrasonic data analysis method according to any one of claims 1 to 5, characterized in that: include: A signal collector, a signal transceiver electrically connected to the signal collector, a motion device, and a plurality of ultrasonic transducers arranged on the motion device; the motion device includes a motion axis and a motion controller; the ultrasonic transducer is communicatively connected to the signal transceiver; The motion controller controls the motion axis to move to a preset position, and sends a trigger signal to the signal transceiver and the signal collector, so that the signals received by the signal transceiver and the signal collector are synchronized; After receiving the trigger signal, the signal transceiver excites the ultrasonic transducer to transmit an ultrasonic signal to the wafer, receives the echo signal collected by the ultrasonic transducer, and then transmits the echo signal to the signal collector; The motion axis is controlled to move, and is used to drive the ultrasonic transducer to move horizontally above the wafer.

7. The ultrasonic testing device according to claim 6, characterized in that: It also includes a water channel system, which provides a coupling medium for the ultrasonic transducer, so that the ultrasonic signal emitted by the ultrasonic transducer is transmitted from the ultrasonic transducer to the surface of the wafer and then enters the interior of the wafer.

8. An ultrasonic data analysis device, characterized in that: include: An acquisition unit, configured to acquire first ultrasonic signals collected by a plurality of ultrasonic transducers; a transform unit, configured to perform a Hilbert transform on the first ultrasonic signal to obtain a transformed second ultrasonic signal; A waveform confirmation unit, configured to find the surface wave based on the comparison result of the second ultrasonic signal and the surface wave threshold value; compare the waveform within a preset time after the surface wave in the second ultrasonic signal with the bonding layer threshold value to find the bonding layer waveform; The defect confirmation unit determines whether there is a delamination defect in the bonding layer based on the amplitude of the bonding layer waveform.

9. An electronic device, characterized in that: The electronic device comprises: at least one processor; and a memory communicatively coupled to the at least one processor; The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the ultrasound data analysis method according to any one of claims 1 to 5.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the ultrasound data analysis method according to any one of claims 1 to 5 when executed.

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