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

Abstract

The present invention provides an ultrasonic detection device, method, apparatus, electronic device, and medium. The method comprises obtaining a first ultrasonic signal collected by multiple ultrasonic transducers; performing a 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 with a surface wave threshold; comparing the waveform within a preset time after the surface wave in the second ultrasonic signal with a bonding layer threshold to find a bonding layer waveform; and determining whether a delamination defect exists in the bonding layer based on the amplitude of the bonding layer waveform. The present invention can avoid the problems of noise in the image and the omission of delamination defects.

Description

Technical Field

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

[0002] Wafer bonding is a critical application process for high-end semiconductor devices. The process is complex, and defects such as bubbles and impurities are prone to forming in the bonding layer, impacting key device performance. These defects are located within the wafer, making them difficult to observe using optical imaging, and difficult to achieve both efficient and accurate detection using methods such as X-ray. Semiconductor bonding ultrasonic inspection equipment uses high-frequency ultrasonic transducers to image internal wafer defects and then utilizes intelligent analysis systems to automatically identify and size these defects. This equipment can be used for product quality monitoring and process analysis to improve quality and efficiency during wafer bonding. It is a test device developed specifically for the wafer bonding production stage.

[0003] This application uses a high-frequency ultrasonic testing system to collect signals from every location on the wafer. The collected signals include surface wave signals (the signal reflected by the ultrasonic wave emitted from the wafer surface) and bonding layer signals (the signal reflected by the ultrasonic wave emitted from the bonding layer). Under normal circumstances, the waveforms of the surface wave and bonding layer signals can be captured as expected. However, when there are bubbles in the water flow or occasional phenomena such as bumps, depressions, and dirt on the surface, there is a possibility that the surface wave and bonding layer waveforms cannot be captured or captured inaccurately. This problem can cause black or white noise in 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 equipment and medium, which can avoid the problems of noise on images and the omission of delamination defects.

[0005] According to one aspect of the present invention, there is provided an ultrasound data analysis method, comprising:

[0006] Acquiring first ultrasonic signals collected by multiple ultrasonic transducers;

[0007] Performing a Hilbert transform on the first ultrasonic signal to obtain a transformed second ultrasonic signal;

[0008] Finding a surface wave based on a comparison result of the second ultrasonic signal and a surface wave threshold value; comparing a waveform within a preset time after the surface wave in the second ultrasonic signal with a bonding layer threshold value to find a bonding layer waveform;

[0009] It is determined whether a delamination defect exists in the bonding layer based on the amplitude of the bonding layer waveform.

[0010] Optionally, finding the surface wave based on a comparison result of the second ultrasonic signal and a surface wave threshold value includes:

[0011] The second ultrasonic signal is compared with a surface wave threshold value, and a waveform of the second ultrasonic signal with a peak value within the range of the surface wave threshold value is determined as a surface wave.

[0012] Optionally, finding the surface wave based on a comparison result of the second ultrasonic signal and a surface wave threshold value includes:

[0013] A waveform whose peak amplitude appears for the first time in the second ultrasonic signal is greater than a surface wave threshold is determined as a surface wave.

[0014] Optionally, after determining whether the bonding layer has a delamination defect based on the amplitude of the bonding layer waveform, the method further includes:

[0015] Acquire the bonding layer waveform corresponding to the first ultrasonic signals collected by the plurality of ultrasonic transducers, and position information on the wafer corresponding to the first ultrasonic signals, to obtain a bonding layer waveform corresponding to each position on the wafer;

[0016] 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.

[0017] Optionally, it also includes:

[0018] S101, calculating the difference between each pixel in the second wafer grayscale image and a first neighborhood pixel; the first neighborhood pixel is a pixel within a first preset range of a pixel; each pixel in the second wafer grayscale image represents the amplitude of the surface wave collected at the corresponding position on the wafer;

[0019] S102: Pixels whose difference exceeds a preset threshold are selected as pixels to be corrected, and the pixels to be corrected are added to a set to be corrected, and the other pixels are used as neighborhood reference points;

[0020] 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 a neighborhood reference point;

[0021] S104, repeat step S103 until all points in the set to be corrected are found;

[0022] S105: If the pixel to be corrected still exists in the set to be corrected but has not been successfully found, 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;

[0023] S106, 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, until all points in the set to be corrected are searched;

[0024] 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.

[0025] According to one aspect of the present invention, an ultrasonic detection device is provided, capable of implementing the ultrasonic data analysis method described in any embodiment of the present invention, comprising: a signal collector, a signal transceiver electrically connected to the signal collector, a motion device, and a plurality of ultrasonic transducers disposed on the motion device; the motion device comprising a motion axis and a motion controller; the ultrasonic transducers being communicatively connected to the signal transceiver;

[0026] 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 as to synchronize the signals received by the signal transceiver and the signal collector.

[0027] 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;

[0028] The motion axis moves under control to drive the ultrasonic transducer to move horizontally above the wafer.

[0029] Optionally, a water system is also included, 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.

[0030] According to another aspect of the present invention, there is provided an ultrasound data analysis device, comprising:

[0031] an acquiring unit, configured to acquire first ultrasonic signals collected by a plurality of ultrasonic transducers;

[0032] a transform unit, configured to perform a Hilbert transform on the first ultrasonic signal to obtain a transformed second ultrasonic signal;

[0033] a waveform confirmation unit, configured to find a surface wave based on a comparison result of the second ultrasonic signal and a surface wave threshold value; and compare a waveform within a preset time after the surface wave in the second ultrasonic signal with a bonding layer threshold value to find a bonding layer waveform;

[0034] The defect confirmation unit determines whether there is a delamination defect in the bonding layer based on the amplitude of the bonding layer waveform.

[0035] According to another aspect of the present invention, an electronic device is provided, comprising:

[0036] at least one processor; and a memory communicatively connected to the at least one processor; wherein,

[0037] The memory stores a computer program that can be executed by the at least one processor. The computer program is executed by the at least one processor to enable the at least one processor to perform the ultrasound data analysis method according to any embodiment of the present invention.

[0038] According to another aspect of the present invention, a computer-readable storage medium is provided, wherein 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 embodiment of the present invention when executed.

[0039] The technical solution of the embodiment of the present invention is to obtain a first ultrasonic signal collected by multiple ultrasonic transducers; perform 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; determine whether there is a delamination defect in the bonding layer based on the amplitude of the bonding layer waveform, thereby solving the problem of noise points on the image and the possibility of delamination defects being missed.

[0040] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0042] Figure 1 is a structural diagram of an ultrasonic detection device provided according to Embodiment 1 of the present invention;

[0043] Figure 2 This is a schematic diagram of the overall structure of a detection device in one embodiment;

[0044] Figure 3 Schematic diagram of Hilbert transform of waveform;

[0045] Figure 4 This is a flow chart of an ultrasonic data analysis method provided according to the second embodiment of the present invention;

[0046] Figure 5 Schematic diagram of the waveform of the echo signal in one embodiment of the present invention;

[0047] Figure 6 1 is a waveform diagram of an echo signal after Hilbert transform in one embodiment of the present invention;

[0048] Figure 7 Schematic diagram of partial imaging of a wafer inspected in one embodiment of the present invention;

[0049] Figure 8 Schematic diagram of waveform when there is no defect in the bonding layer in one embodiment of the present invention;

[0050] Figure 9 A waveform diagram showing a case where a bonding layer has defects in one embodiment of the present invention;

[0051] Figure 10 A first wafer grayscale image is obtained by converting a bonding layer signal into a grayscale value in an embodiment of the present invention;

[0052] Figure 11 is a flow chart of an intelligent error correction method in one embodiment of the present invention;

[0053] Figure 12 This is a structural diagram of an ultrasonic data analysis device provided according to a third embodiment of the present invention;

[0054] Figure 13 It is a structural diagram of an electronic device for implementing the ultrasonic data analysis method of the present invention. DETAILED DESCRIPTION

[0055] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0056] It should be noted that the terms "first", "second", etc. in the description, claims, and drawings of the present invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way are interchangeable where appropriate 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 "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or that are inherent to these processes, methods, products, or apparatus.

[0057] Wafer bonding is a key application process for high-end semiconductor devices. The process is difficult, and bubbles, impurities and other process defects that affect the key performance of the device are prone to appear in the bonding layer. These defects are inside the wafer and are difficult to observe using optical imaging and other methods. It is difficult to achieve both detection efficiency and accuracy using detection methods such as X-ray. Semiconductor bonding ultrasonic detection equipment uses a high-frequency ultrasonic transducer to image internal defects in the wafer, and then uses an intelligent analysis system to automatically identify and size-classify internal defects in the wafer. It can be used for product quality monitoring and process analysis to alleviate wafer bonding, in order to achieve the goal of improving quality and efficiency. It is a detection equipment developed for the wafer bonding production stage. The equipment used in this application is a high-frequency ultrasonic detection system.

[0058] The requirements for ultrasonic testing systems include the following:

[0059] 1. Scanning accuracy: The highest scanning accuracy is 50um, and the scanning accuracy can be set.

[0060] 2. Efficiency: 6 pieces / hour at 50*50um (interlaced interpolation), 12 pieces / hour at 100*100um (interlaced scanning);

[0061] 3. Product specifications: 12-inch bonded wafer, made of silicon, product thickness 1600um, thickness from the layer to be tested to the wafer surface 775um;

[0062] 4.Scanning mode: A-Scan, C-Scan, X-Scan, TOF-Scan, Z-Scan.

[0063] Example 1

[0064] Figure 1 A structural diagram of an ultrasonic detection device is provided for the first embodiment of the present invention. Figure 1 As shown, the device includes: 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 transducer is communicatively connected to the signal transceiver;

[0065] 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 as to synchronize the signals received by the signal transceiver and the signal collector.

[0066] 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;

[0067] The motion axis moves under control to drive the ultrasonic transducer to move horizontally above the wafer.

[0068] It should be noted that the motion controller is used to control the motion axis to move to a preset position, 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 the specified position on the wafer and injects it into the wafer; and receives the echo signal of the ultrasonic signal. The echo signal is received by the signal transceiver and 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. The motion control signal sent by the motion controller controls the motion of the motion axis.

[0069] It should be noted that in the present application, the motion controller can simultaneously send trigger signals to the signal transceiver and the signal collector to ensure the synchronization and accuracy of the signals received by the signal transceiver and the signal collector.

[0070] 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.

[0071] It should be noted that the water system provides a continuous water flow, providing an ultrasonic coupling medium for ultrasonic waves. This allows for efficient transmission of ultrasonic waves from the ultrasonic transducer to the wafer surface and then into the wafer interior, ensuring the quality and strength of the detection signal. Furthermore, the acoustic impedance of the water in the ultrasonic probe and the wafer differ. A suitable water system can adjust the acoustic impedance transition, reducing ultrasonic reflection at the interface and allowing more ultrasonic energy to enter the wafer, thereby improving detection sensitivity and accuracy. Furthermore, when ultrasonic imaging equipment is in operation, components such as the ultrasonic transducer generate heat. Prolonged operation can cause excessive temperatures, impacting the performance and lifespan of the equipment. The water in the water system circulates to remove this heat, providing cooling and dissipation, and maintaining stable operation of the equipment. During the detection process, the water in the water system can also rinse the wafer surface to remove contaminants such as dust and impurities, preventing these contaminants from affecting the transmission and reflection of ultrasonic waves. This improves the accuracy of the detection results and prevents contaminants from damaging the ultrasonic transducer.

[0072] It also includes an air knife, which is used to blow out high-speed airflow after the inspection is completed to quickly dry the moisture on the surface of the wafer and keep the wafer dry. It can also blow away tiny particles, dust and other impurities on the surface of the wafer, further improving the cleanliness of the wafer surface and ensuring the accuracy of the inspection and the quality of the wafer. In addition, the airflow blown by the air knife can exert a certain pressure on the wafer, playing a role in assisting in positioning and fixing the wafer, ensuring that the wafer maintains a stable position during the inspection process, and improving the accuracy and repeatability of the inspection. Especially for some thin wafers, the airflow of the air knife can provide additional support to prevent the wafer from shaking or shifting during the inspection process.

[0073] In such Figure 2 In the illustrated embodiment, the ultrasonic data acquisition device includes a dryer, a wafer loader (Loadport), an edge detector, a wafer spin dryer, a wafer robot, and a wafer inspection platform.

[0074] a. Wafer loader is used to place wafer cassettes;

[0075] b. The upper arm of the wafer robot takes the first wafer from the cassette and places it on the edge finder for edge finding, straightening and center correction;

[0076] c. The arm of the robot takes the sheet from the edge finder and places it on the wafer inspection platform and vacuums it;

[0077] d. The motion control platform starts moving and the probe starts collecting ultrasonic signals;

[0078] e. The robot takes the second wafer from the cassette and places it on the edge finder for edge finding, straightening, and center correction. The robot then takes the wafer from the edge finder and places it on the wafer inspection platform for vacuuming. The robot then waits for the ultrasonic signal acquisition process of the first wafer to complete.

[0079] f. After collecting the complete wafer signal, use a hair dryer to blow away most of the water stains on the wafer surface;

[0080] g. The wafer inspection platform (Chuck) releases the vacuum, and the lower arm of the robot removes the wafer from the wafer inspection platform (Chuck) and places a new wafer on the upper arm;

[0081] h. The robot places the wafer into the dryer to allow the wafer to be further dried;

[0082] i. The robotic arm goes deep into the dryer for drying;

[0083] 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;

[0084] k. After edge finding is completed, the robot arm takes out the wafer and puts it back into the wafer loader;

[0085] l. The robot begins processes a, b, and c for the third wafer and continues the cycle until all wafers in the wafer loader have been inspected.

[0086] In one embodiment, for different usage scenarios, it is necessary to select corresponding probes in a targeted manner, and the main considerations include: 1. Sample thickness, the corresponding probe parameter is the probe focal length; 2. Lateral resolution, which mainly examines the resonant frequency of the probe and the acoustic beam width of the focal area; 3. Axial resolution. The higher the axial resolution requirement, the shorter the pulse duration needs to be, the higher the probe frequency needs to be, and the greater the damping needs to be.

[0087] a. Frequency: Generally, the higher the probe frequency, the higher the measurement accuracy. The probe frequency generally refers to the frequency when the object under test is closest to the probe in water. Because ultrasonic waves are attenuated when propagating in the medium, this nominal frequency is not the actual frequency used. In this scenario, a 100MHz probe is selected to detect defects larger than 25µm.

[0088] b. Focal Length - Underwater: The nominal focal length generally refers to the probe's optimal operating height in water (this system uses a probe with a focal length of 12.7mm). Different probes of the same model may have slightly different focal lengths. The test method is to move the probe to a position at the nominal focal length from the surface of the object being measured and adjust the Z-axis height in steps of 0.1mm until the echo from the surface of the object being measured (hereinafter referred to as the surface wave) reaches its maximum intensity. At this point, the Z-axis height is the probe's focal length in water.

[0089] c. Focal length - DUT: The speed of sound on the DUT wafer is different from the speed of sound in water. During ultrasonic wave propagation, refraction occurs on the water and wafer surfaces. The focal length on the wafer is smaller than that in water. To determine the focal length on the DUT, the probe needs to be moved downward on the Z-axis to maximize the echo signal amplitude at the DUT surface and bonding layer of the wafer. In this application scenario, the probe needs to be lowered 7-8mm, and the echo signal amplitude at the bonding layer is the largest. This is the focal length used for the DUT.

[0090] d. Focal range: The focal range is assessed by moving the probe up and down along the Z axis, based on the focal length. The Z-axis range where the echo signal amplitude is greater than half the amplitude at the focal length is the focal range. In this scenario, the focal range is approximately 2 mm.

[0091] 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 operating frequency of the probe (this probe is about 62MHz). The corresponding maximum resolution is 20um~30um.

[0092] f. -6dB bandwidth: The resolution bandwidth represents the ability to distinguish between 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 as the resolution bandwidth. In a practical example, the resonant frequency intensity is 66dB, -6dB is 60dB, the corresponding frequency range is 47.8MHz to 81MHz, and the -6dB bandwidth is 33.2MHz.

[0093] g. Pulse width: The pulse width is determined by the bandwidth and is generally tens of ns. The narrower the pulse width, the higher the resolution in the Z-axis direction. In this scenario, the pulse width is required to be less than 100ns and the Z-axis resolution accuracy is 75um, which meets 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). The pulse width is generally evaluated by -20dB in the industry. Figure 3 As shown in FIG. 1 , after Hilbert transform, the horizontal axis of the waveform is the time axis, and the vertical axis amplitude is normalized to between 0 and 1. -20dB is the position of 0.1 on the vertical axis, and the corresponding horizontal axis -20dB bandwidth is about 58ns.

[0094] In one embodiment, during machine commissioning: (Here, a 12-inch wafer (300mm*300mm) is used as an example):

[0095] a. Set the wafer size;

[0096] b. Set the wafer direction, i.e. the direction of the notch on the wafer, and set the wafer rotation angle on the edge finder;

[0097] c. Set the position of the wafer on the wafer stage and calibrate the position of the robot to pick up and place the wafer;

[0098] d. Scan the 350*350mm acquisition area, with each probe collecting 87.5mm in the Y direction and forming an image;

[0099] e. Calibrate the position deviation between each probe according to the interleaving range of the image;

[0100] f. Scan the image again to verify that the wafer images completely overlap to form a standard circle;

[0101] g. Determine the minimum scanning area (305mm*305mm) based on the wafer's position in the image.

[0102] h. After completing the above steps, the entire wafer area can be scanned within the minimum scanning range.

[0103] In one embodiment, debugging the ultrasound system parameters includes:

[0104] The ultrasound system is mainly composed of a trigger (motion controller), an ultrasonic pulse transceiver, a probe, an acquisition card, and related cables. The components include:

[0105] a. Trigger: The trigger is integrated into the motion controller. The main parameters for the trigger are the trigger interval (trigger frequency) and the trigger voltage. The trigger interval must match the scanning accuracy, and the trigger voltage must match the minimum operating voltage of the ultrasonic pulse transceiver, 3.3V. For example, if the scanning accuracy is 100um*100um, the X-axis will be triggered every 100um of movement, and the Y-axis will move 100um after the X-axis completes one line of movement. The trigger voltage is determined by the parameters of the ultrasonic pulse transceiver.

[0106] b. Ultrasonic pulse transceiver: The ultrasonic pulse transceiver has the following parameters that need to be set:

[0107] (1) Working mode: transmission or echo mode, echo mode is used here;

[0108] (2) Gain: signal amplification factor. This parameter needs to be used in conjunction with the acquisition card range parameter to make the measured signal strength close to the full range.

[0109] (3) Low / high pass filter: Set the echo frequency range to be collected. This project uses 30-300MHz, mainly filtering low-frequency components to prevent noise;

[0110] (4) Trigger source: external, triggered by a trigger;

[0111] (5) Voltage: 330~380V, the default is to use low voltage 330V to extend the life of the probe;

[0112] (6) Energy: low / high, low is used by default to extend the life of the probe;

[0113] (7) Impedance: 25~100Ohms, select the impedance according to the probe, here select 100Ohms;

[0114] c. Acquisition card: The sampling frequency must match at least five times the probe's signal frequency. This project uses a 1GHz sampling frequency. The sampling length should be 1024 or 2048, and should be set based on the degree of surface warpage. The higher the warpage, the longer the sampling length. The measurement range, expressed in millivolts, must be used in conjunction with the gain parameters of the ultrasonic pulse transceiver to maximize the amplitude of the surface wave and bond layer echo without exceeding the measurement range. In this project, the acquisition card's 200mV range was used with a pulse transceiver with a 40dB gain.

[0115] d. Probe: The probe needs to adjust its focal length so that the test plane is in the optimal imaging range, that is, the signal intensity (A-wave amplitude) of the profile to be tested is the maximum.

[0116] It should be noted that under normal circumstances, both surface waves and bond layer waveforms can be captured as expected. However, when bubbles are present in the water flow, or when there are surface bumps, depressions, dirt, or other unforeseen conditions, the surface waves and bond layer waveforms may not be captured or may be captured inaccurately. This can result in black or white noise in the image and the possibility of missing delamination defects. To address these two issues, we have developed two approaches: surface tracking and intelligent error correction.

[0117] If a smaller threshold range is used for surface wave search, the position search of the surface wave will be limited. If there is a certain degree of wafer warpage or ultrasonic fluctuations, the surface wave cannot be found. If a larger threshold range is used, the reflected wave of the bonding layer or other interfering noise may be mistakenly found as the surface wave, resulting in false detection or missed detection.

[0118] Example 2

[0119] In order to solve the above problems, this application provides an ultrasonic data analysis method, such as Figure 4 As shown, the method includes:

[0120] S10, obtaining first ultrasonic signals collected by multiple ultrasonic transducers,

[0121] It should be noted that the first ultrasonic signal is the echo signal collected by the ultrasonic transducer from a position on the wafer, and 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 surface of the wafer, and the bonding layer signal is the echo signal of the ultrasonic wave passing through the wafer surface and entering the bonding layer inside the wafer, the signal transceiver will first receive the surface wave signal and then receive the bonding layer signal. In addition, each unit position on the wafer corresponds to a first ultrasonic signal, that is, the first ultrasonic signal collected by multiple ultrasonic transducers can detect the bonding status 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.

[0122] S20: Perform a Hilbert transform on the first ultrasonic signal to obtain a transformed second ultrasonic signal.

[0123] S30, finding the surface wave based on the comparison result of the second ultrasonic signal and the surface wave threshold value; comparing the waveform of the second ultrasonic signal within a preset time after the surface wave with the bonding layer threshold value to find the bonding layer waveform,

[0124] It should be noted that since the surface wave and bond layer waveforms have a temporal sequence (surface wave precedes bond layer waveform), and surface wave amplitudes are typically larger than bond layer waveform amplitudes, a surface wave threshold can be set to identify the surface wave, and the waveform that appears after the surface wave is compared with the bond layer threshold to determine the bond layer waveform.

[0125] S40: Determine whether the bonding layer has a delamination defect based on the amplitude of the bonding layer waveform.

[0126] Generally, when the peak value of the bonding layer waveform is large, it indicates that there may be defects in the bonding condition at that wafer position.

[0127] In one embodiment, after the ultrasonic signal acquisition is completed, the process of analyzing the data includes:

[0128] a. Converting ultrasonic signals into images: For ultrasonic signals collected by the ultrasonic transducer, analyze the acquired ultrasonic waveform data according to a certain step size (50 μm or 100 μm). The steps are as follows:

[0129] 1. The waveform of a single position point is generally 8-bit data with a length of 1024 sampling points or 2048 sampling points (or 12-bit or 16-bit, depending on the sampling length of the acquisition card);

[0130] like Figure 5As shown, the ultrasonic echo with a single point length of 2048 is collected, and the sampling frequency is 1.25GHz. In the unprocessed ultrasonic graph, 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;

[0131] 2. Perform Hilbert transform on the collected single points and normalize all amplitudes to the positive axis;

[0132] The waveform after Hilbert transformation is as follows Figure 6 As shown, the yellow waveform is the waveform after Hilbert transform;

[0133] 3. Set the data threshold to identify surface waves (surface waves refer to the amplitude of the waveform returned by ultrasound when it contacts the wafer surface);

[0134] like Figure 6 As shown in the figure, the surface wave threshold amplitude is 100-1100 μm. 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 numerical coordinates of <position, amplitude> corresponding to the surface wave peak are <900, 84>.

[0135] 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 tested) to detect whether there is a delamination defect in the bonding layer to be tested. 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;

[0136] It should be noted that since the surface wave is the echo signal of the ultrasonic wave transmitted 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 inside the wafer, the signal transceiver will receive the surface wave signal first and then the bonding layer echo signal;

[0137] Figure 7 This is a local image of the wafer being tested. White dots represent bubble defects in the bonding layer, and black dots represent normal ones. Figure 9 It is a white dot waveform. Figure 8 The black dot waveform has a larger amplitude at the red vertical line, which reflects that the peak value of the bonding layer waveform is larger, that is, the bonding layer waveform at this position has a defect; the black dot waveform has a smaller amplitude at the red line, indicating that there is no defect in the bonding layer;

[0138] 5. Normalize the bonding layer data in the echo signal obtained in step 4 to a range of 0-255 to obtain the signal intensity of the bonding layer;

[0139] 6. Plot the signal intensity obtained in 5 on the image. At this time, the data contains three pieces of information: the horizontal and vertical coordinates x and y on the plane, and the signal intensity (i.e., amplitude) d at that point. Plot the point information on a picture representing the wafer, and plot the grayscale of the pixel at the coordinates (x, y) on the picture as d.

[0140] 7. After the signal processing of all acquisition points is completed, a complete grayscale image of the bonding layer of the wafer can be obtained. Figure 10 shown.

[0141] The image can be analyzed. For example, the circular area within the white border of the image obtained in step 7 is extracted as the effective area to be detected. The white point area within the effective area is extracted according to a certain threshold value, and the pixel area of each white point is calculated (in terms of Figure 10 For example, each pixel represents 100 μm. According to the defect classification settings (for example, defects are divided into 100-300 μm, 300-500 μm, and greater than 500 μm), the white spot area is divided into defects of different sizes.

[0142] In one embodiment, finding the surface wave based on a comparison result of the second ultrasonic signal and a surface wave threshold value includes:

[0143] The second ultrasonic signal is compared with a surface wave threshold value, and a waveform of the second ultrasonic signal with a peak value within the range of the surface wave threshold value is determined as a surface wave.

[0144] In this embodiment, the second ultrasonic signal converted from the echo signal can be directly compared with the surface wave threshold, and the waveform of the second ultrasonic signal with a peak value within the surface wave threshold range is determined as a surface wave, thereby quickly detecting the surface wave.

[0145] In one embodiment, finding the surface wave based on the comparison result of the second ultrasonic signal and the surface wave threshold value may further include:

[0146] A waveform whose peak amplitude appears for the first time in the second ultrasonic signal is greater than a surface wave threshold is determined as a surface wave.

[0147] In this embodiment, the first waveform in the second ultrasonic signal with a peak amplitude greater than the surface wave threshold can be directly determined as a surface wave. This solution can stably obtain the correct surface wave without being affected by wafer warpage and other interference.

[0148] In one embodiment, after determining whether the bonding layer has a delamination defect based on the amplitude of the bonding layer waveform, the method further includes:

[0149] Acquire the bonding layer waveform corresponding to the first ultrasonic signals collected by the plurality of ultrasonic transducers, and position information on the wafer corresponding to the first ultrasonic signals, to obtain a bonding layer waveform corresponding to each position on the wafer;

[0150] 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.

[0151] It should be noted that the amplitude value of the bonding layer waveform can be normalized according to the range of the grayscale value space 0-255, and the amplitude value of the bonding layer waveform collected at each unit position on the wafer can be converted into a grayscale value, and then the first wafer grayscale image reflecting the distribution of various defects on the wafer can be obtained.

[0152] In one embodiment, if Figure 11 The intelligent error correction method shown, Figure 11 Included are:

[0153] S101, calculating the difference between each pixel in the second wafer grayscale image and a first neighborhood pixel; the first neighborhood pixel is a pixel within a first preset range of a pixel; each pixel in the second wafer grayscale image represents the amplitude of the surface wave collected at the corresponding position on the wafer;

[0154] S102: Pixels whose difference exceeds a preset threshold are selected as pixels to be corrected, and the pixels to be corrected are added to a set to be corrected, and the other pixels are used as neighborhood reference points;

[0155] 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 a neighborhood reference point;

[0156] S104, repeat step S103 until all points in the set to be corrected are found;

[0157] S105: If the pixel to be corrected still exists in the set to be corrected but has not been successfully found, 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;

[0158] S106, 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, until all points in the set to be corrected are searched;

[0159] 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.

[0160] It should be noted that during ultrasonic scanning, tens of millions of points may need to be collected. During this process, surface waves may become unstable or weak, making them unrecognizable, due to factors such as tiny bubbles in the water flow, free impurities, and bumps and hexagonal silicon on the wafer surface. This can generate noise, which can interfere with the stability of the test results. Due to the high standard for wafer flatness (≤±20µm), all surface waves should appear close together in a local area. If any surface waves appear outside this range, this indicates interference caused by the aforementioned factors, leading to inaccurate surface wave search. Inaccurate surface wave search can lead to inaccurate bond layer search, which in turn introduces noise. Therefore, pixels whose difference exceeds a preset threshold may be inaccurately searched, and the pixel converted from the bond layer waveform at that point needs to be used as a neighborhood reference point for re-search.

[0161] In this embodiment, the difference between a pixel and its neighboring pixels is determined to determine whether the pixel requires correction. The pixel at all unit locations on the wafer is then calculated to find the pixel requiring correction, which is then corrected, resulting in a corrected second wafer grayscale image. Intelligent error correction can eliminate noise points caused by abnormal conditions.

[0162] Example 3

[0163] Figure 12 The third embodiment of the present invention provides an ultrasonic data analysis device, such as Figure 12 As shown, the device includes:

[0164] An acquisition unit 110 is configured to acquire first ultrasonic signals collected by a plurality of ultrasonic transducers;

[0165] a transform unit 120, configured to perform a Hilbert transform on the first ultrasonic signal to obtain a transformed second ultrasonic signal;

[0166] The waveform confirmation unit 130 is configured to find the surface wave based on the comparison result of the second ultrasonic signal and the surface wave threshold value; and compare the waveform of the second ultrasonic signal within a preset time after the surface wave with the bonding layer threshold value to find the bonding layer waveform;

[0167] The defect confirmation unit 140 determines whether there is a delamination defect in the bonding layer based on the amplitude of the bonding layer waveform.

[0168] The ultrasonic data analysis device provided in the embodiment of the present invention can execute the ultrasonic data analysis method provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0169] Example 4

[0170] Figure 13 A schematic diagram of an electronic device 10 that can be used to implement an embodiment of the present invention is shown. 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 assistants, cellular phones, smartphones, 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.

[0171] like Figure 13 As shown, electronic device 10 includes at least one processor 11 and memory, such as read-only memory (ROM) 12 and random access memory (RAM) 13, communicatively connected to at least one processor 11. The memory stores computer programs executable by the at least one processor. Processor 11 can perform various appropriate actions and processes based on the computer programs stored in ROM 12 or loaded from storage unit 18 into RAM 13. RAM 13 can also store various programs and data required for the operation of electronic device 10. Processor 11, ROM 12, and RAM 13 are interconnected via bus 14. An input / output (I / O) interface 15 is also connected to bus 14.

[0172] 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 via a computer network such as the Internet and / or various telecommunication networks.

[0173] The processor 11 can be any general-purpose and / or specialized processing component 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 specialized artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any other suitable processor, controller, microcontroller, etc. The processor 11 executes the various methods and processes described above, such as an ultrasound data analysis method.

[0174] In some embodiments, an ultrasound data analysis method may be implemented as a computer program tangibly embodied in a computer-readable storage medium, such as the storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or installed on 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 ultrasound data analysis method described above may be performed. Alternatively, in other embodiments, the processor 11 may be configured to perform an ultrasound data analysis method in any other suitable manner (e.g., via firmware).

[0175] Various embodiments of the systems and techniques described above can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), system-on-chip systems (SOCs), programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments can include being implemented in one or more computer programs that are executable and / or interpreted on a programmable system that includes 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 data and instructions to the storage system, the at least one input device, and the at least one output device.

[0176] Computer programs for implementing the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may 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 program is executed by the processor, the functions / operations specified in the flowcharts and / or block diagrams are implemented. The computer program may 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.

[0177] In the context of the present invention, a computer-readable storage medium may be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, device, or apparatus. A computer-readable storage medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or apparatus, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. More specific examples of machine-readable storage media may include an electrical connection based on one or more wires, a portable computer disk, 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 disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0178] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device that has: 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 pointing device (e.g., a mouse or trackball) through which the user can provide input to the electronic device. Other types of devices can also be used to provide interaction with the user; for example, the 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, voice input, or tactile input).

[0179] The systems and techniques described herein can be implemented in a computing system that includes back-end 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 front-end components (e.g., a user computer with a graphical user interface or web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such back-end components, middleware components, or front-end 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: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0180] A computing system may include clients and servers. The clients and servers are typically remote from each other and typically interact via a communication network. This client-server relationship arises through computer programs running on the respective computers, creating a client-server relationship. The server may be a cloud server, also known as a cloud computing server or cloud host. This server is a hosting product within the cloud computing service ecosystem that addresses the management difficulties and limited scalability of traditional physical hosting and VPS services.

[0181] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present invention can be performed 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. This is not limited herein.

[0182] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A method for analyzing ultrasonic data, characterized in that: include: Acquiring first ultrasonic signals collected by multiple ultrasonic transducers; Performing a 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 within a preset time after the surface wave in the second ultrasonic signal with a bonding layer threshold value to find a bonding layer waveform; determining whether a delamination defect exists in the bonding layer based on the amplitude of the bonding layer waveform; The finding of the surface wave based on the comparison result of the second ultrasonic signal and the surface wave threshold value includes: determining a waveform in the second ultrasonic signal having a peak amplitude greater than a surface wave threshold value that appears for the first time as a surface wave; After determining whether the bonding layer has a delamination defect based on the amplitude of the bonding layer waveform, the method further includes: Acquire the bonding layer waveform corresponding to the first ultrasonic signals collected by the plurality of ultrasonic transducers, and position information on the wafer corresponding to the first ultrasonic signals, to obtain a 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.

2. The ultrasonic data analysis method according to claim 1, characterized in that: The finding of the surface wave based on the comparison result of the second ultrasonic signal and the surface wave threshold value includes: The second ultrasonic signal is compared with a surface wave threshold value, and a waveform of the second ultrasonic signal with a peak value 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: 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: Pixels whose difference exceeds a preset threshold are selected as pixels to be corrected, and the pixels to be corrected are added to a set to be corrected, and the other pixels are used as 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 a neighborhood reference point; S104, repeat step S103 until all points in the set to be corrected are found; S105: If the pixel to be corrected still exists in the set to be corrected and has not been successfully found, 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 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, until all 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.

4. An ultrasonic detection device capable of implementing the ultrasonic data analysis method according to any one of claims 1 to 3, 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 disposed 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 to synchronize the signals received by the signal transceiver and the signal collector; 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 moves under control to drive the ultrasonic transducer to move horizontally above the wafer.

5. The ultrasonic testing device according to claim 4, 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.

6. An ultrasonic data analysis device, characterized in that: include: an acquiring 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 a surface wave based on a comparison result of the second ultrasonic signal and a surface wave threshold value; and compare a waveform within a preset time after the surface wave in the second ultrasonic signal with a bonding layer threshold value to find a bonding layer waveform; A defect confirmation unit is configured to determine whether a delamination defect exists in the bonding layer based on the amplitude of the bonding layer waveform.

7. An electronic device, characterized in that: The electronic device comprises: 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. The computer program is executed by the at least one processor to enable the at least one processor to perform the ultrasound data analysis method according to any one of claims 1 to 3.

8. 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 3 when executed.

Images