Dendritic crystal growth evolution-based electrochemical migration failure prediction analysis method

Abstract

An electrochemical migration failure prediction analysis method based on dendritic crystal growth evolution comprises the following steps: carrying out an electrochemical migration experiment on a prepared test sample on a self-established electrochemical migration experiment platform, and monitoring the test sample in the electrochemical migration experiment through a digital three-dimensional video microscope. The formation condition of the dendritic crystal in the electrode spacing and the microstructure morphology change image are obtained, and a visual basis is provided for determining the growth position and rule of the dendritic crystal; matlab software is combined to carry out two-dimensional gray level conversion, contrast enhancement and noise reduction processing on a microstructure morphology change image on the surface of a test sample, and dendritic crystal surface area statistics is carried out on the processed dendritic crystal growth two-dimensional gray level image, so that dendritic crystal generation, evolution distribution characteristics and morphology characteristics in the electrochemical migration process are accurately reflected; compared with an existing electrochemical migration failure prediction analysis method, the method has better dynamic monitoring capacity, high real-time performance and high accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic packaging, and in particular to an electrochemical migration failure prediction and analysis method based on dendrite growth evolution. Background Art

[0002] As integrated circuits become increasingly powerful and component sizes continue to shrink, the distance between solder joints and electrodes is shrinking dramatically, posing a significant challenge to device reliability during service. High electric field gradients between adjacent electrodes make metal materials susceptible to electrochemical reactions under the combined effects of electric fields, humidity, and other environmental factors. The resulting metal ions diffuse and migrate between the electrodes, forming dendrites on the electrode surfaces, leading to device performance degradation and even short-circuit failure. Therefore, analyzing and predicting dendrite evolution during electrochemical migration not only helps reveal the laws and mechanisms of electrochemical migration failure, but also facilitates the prediction of electrochemical migration failure.

[0003] Typically, dendrite growth analysis during electrochemical migration is implemented through scanning electron microscopy and numerical simulation to characterize the onset and end states of electrochemical migration failure. Scanning electron microscopy is a commonly used method for characterizing material microstructures. By observing the morphological changes and distribution of dendrites under scanning electron microscopy, the failure patterns of electrochemical migration can be preliminarily inferred. The numerical simulation method establishes a dendrite growth phase field model that couples stress, thermal, and electrochemical fields to study the dendrite growth morphology and evolution under the influence of ambient temperature, external voltage, and the coupling of these two conditions.

[0004] At present, the research on electrochemical migration process mostly relies on numerical simulation and offline morphology characterization methods. However, these methods have obvious limitations. Most of them are aimed at characterizing the start and end states of electrochemical migration failure and cannot analyze the dendrite evolution process. At the same time, the establishment of a numerical simulation model requires the combination of certain assumptions and model parameters, which cannot accurately predict the growth and evolution of dendrites. Therefore, it is necessary to establish an electrochemical migration in-situ experimental system, observe the ion migration and metal deposition process in real time, and statistically analyze parameters such as dendrite area to achieve quantitative characterization of dendrite morphology. This can accurately reflect the failure law of electrochemical migration and is of great significance for the effective prediction and inhibition of electrochemical migration of electronic packaging structures.

[0005] Zhao Lu (Zhao Lu. Electrochemical reaction model of zinc-air battery and study on dendrite growth inhibition [D]. Kunming University of Science and Technology, 2021.) proposed a zinc-air battery electrochemical reaction model and dendrite growth inhibition study, and conducted two tests on the assembled zinc-air battery: first, a constant current charge and discharge method was used to perform 50 charge, standstill and discharge cycles; second, a constant current charge and discharge method was used to perform 50 charge and discharge cycles; -2A pure discharge test was conducted for 9 hours at a current density of 1000 nm. After two tests, the VEGA3 tungsten filament scanning electron microscope of the Kunming University of Science and Technology Testing Center was used to characterize the morphology of the dendrites grown on the surface of the zinc negative electrode and observe the growth of the dendrites. Although this research method can use a scanning electron microscope to observe high-resolution images of the dendrite morphology on the surface of the zinc negative electrode, it can only capture static images and lacks dynamic monitoring. It is impossible to track the dynamic growth process of dendrites in the zinc-air battery during the charging and discharging process and the pure discharge process in real time.

[0006] Patent document with application number CN202111150153.0 discloses a method for in-situ imaging of the dendrite growth process of a battery. The method simulates the electrochemical reaction of the battery through an electrochemical reaction cell that can be used for optical microscope observation; an optical microscope is used to align the electrochemical reaction cell, and the incident angle is adjusted to make the light totally reflected at the dendrite growth interface, adjust the luminescence wavelength and luminescence power, and optimize the image; the electrochemical reaction cell is charged and discharged at a set current density, and during the charge and discharge time, a camera connected to the optical microscope is used for continuous exposure to obtain a time-series image; finally, the early image at a set time interval is used as the background, and the image subtraction algorithm is used to perform background subtraction to obtain a time-series image of the growth site, and then image fitting is used to perform dendrite growth site positioning analysis and multi-frame image merging to generate a super-resolution image; this method uses an optical microscope combined with super-resolution imaging technology to observe the dendrite growth process, but the in-situ optical technology is affected by the optical diffraction limit and may not be able to effectively obtain detailed dynamic information of small-scale dendrites in the initial growth stage of microdendrites. Summary of the Invention

[0007] In order to overcome the defects of the above-mentioned prior art, the purpose of the present invention is to provide an electrochemical migration failure prediction and analysis method based on dendrite growth evolution. By conducting an electrochemical migration experiment on the prepared test sample on an independently constructed electrochemical migration experimental platform, and monitoring the test sample in the electrochemical migration experiment through a digital three-dimensional video microscope, the formation of dendrites in the electrode spacing and the image of microstructure morphology changes are obtained, providing an intuitive and visual basis for determining the position and law of dendrite growth; combined with Matlab software, the microstructure morphology change image on the surface of the test sample is subjected to two-dimensional grayscale conversion, contrast enhancement and noise reduction processing, and the dendrite surface area of ​​the processed two-dimensional grayscale image of dendrite growth is statistically analyzed, accurately reflecting the dendrite generation, evolution distribution characteristics and morphological characteristics during the electrochemical migration process; compared with the existing electrochemical migration failure prediction and analysis method, this method has better dynamic monitoring capability, strong real-time performance and high accuracy.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is:

[0009] A method for predicting and analyzing electrochemical migration failure based on dendrite growth evolution, comprising:

[0010] Conduct electrochemical migration experiments on test samples on an electrochemical migration experimental platform, and monitor the microstructure changes on the surface of the test samples during the electrochemical migration experiment using a digital three-dimensional video microscope.

[0011] Matlab software was used to perform two-dimensional grayscale conversion, contrast enhancement, and noise reduction on the microstructure morphology change image of the test sample surface to obtain a two-dimensional grayscale image of the dendrite growth on the test sample surface.

[0012] Matlab software was used to count the dendrite surface area of ​​the two-dimensional grayscale image of dendrite growth on the surface of the test sample to obtain the dendrite distribution characteristics caused by electrochemical migration.

[0013] Furthermore, the test sample specifically includes:

[0014] A copper-clad laminate was used as the substrate for the PCB board. A "Y"-shaped circuit design of the C module was adopted on the entire PCB board. A silver plating layer with a thickness of 0.15 to 0.2 μm was deposited on the surface of two parallel copper traces of the "Y"-shaped circuit with a spacing of 0.3 to 0.6 mm through an immersion silver process to form a test sample.

[0015] Furthermore, the construction of the electrochemical migration experimental platform specifically includes:

[0016] Connect the signal output of the NI data acquisition system to the signal input of the control computer, and use the control computer to test the functional integrity of the NI data acquisition system board.

[0017] Connect the constant voltage power supply, protective resistor R0, and the two dedicated terminals of the test sample in series, and use a multimeter test lead to perform a continuity test on all interconnected nodes between the constant voltage power supply, protective resistor R0, and the two dedicated terminals of the test sample.

[0018] Connect the spring terminal connector of the NI data acquisition system to both ends of the protection resistor R0, turn on the constant voltage power supply, set the rated output voltage of the constant voltage power supply, and use a multimeter test lead to touch the electrodes of the test sample; if the absolute deviation between the voltage displayed by the multimeter and the rated output voltage of the constant voltage power supply is less than or equal to 2% of the rated output voltage of the constant voltage power supply, it indicates that all circuits of the electrochemical migration experiment platform are connected correctly and the electrochemical migration experiment platform is set up; if the absolute deviation between the voltage displayed by the multimeter and the rated output voltage of the constant voltage power supply is greater than 2% of the rated output voltage of the constant voltage power supply, it is necessary to recheck and reconnect all circuits of the electrochemical migration experiment platform.

[0019] Furthermore, the electrochemical migration experiment is performed on the test sample on the electrochemical migration experiment platform, and the image of the microstructure morphology change of the test sample surface during the electrochemical migration experiment is monitored by a digital three-dimensional video microscope, specifically including:

[0020] Remove the test sample from the circuit of the electrochemical migration experiment platform and rinse it with deionized water. After the electrode surface of the test sample is air-dried, connect the test sample back to the circuit of the electrochemical migration experiment platform and turn on the NI data acquisition system.

[0021] Place the test sample connected to the circuit under a digital 3D video microscope, press the test sample tightly with a glass slide, and then use a pipette to drip electrolyte onto the electrode surface of the test sample;

[0022] Turn on the constant voltage power supply, use the NI data acquisition system to monitor the current I and voltage U across the protection resistor R0 in real time, and use a digital three-dimensional video microscope to observe the formation of dendrites in the electrode spacing of the test sample in real time, and simultaneously obtain the image of the microstructure change of the test sample surface and transmit it to the control end computer; when the current I across the protection resistor R0 reaches the threshold current I max This marks the completion of the entire electrochemical migration experiment.

[0023] Furthermore, the use of Matlab software to sequentially perform two-dimensional grayscale conversion, contrast enhancement, and noise reduction on the microstructure morphology change image of the test sample surface to obtain a two-dimensional grayscale image of dendrite growth on the test sample surface specifically includes:

[0024] The RGB to grayscale function in Matlab software was used to convert the microstructure morphology change image of the test sample surface into two-dimensional grayscale;

[0025] The adaptive histogram equalization function in Matlab software was used to enhance the contrast of the microstructure morphology change image after two-dimensional grayscale conversion;

[0026] The Gaussian filter function and median filter function in Matlab software were used to reduce the noise of the contrast-enhanced microstructure morphology change image to obtain a two-dimensional grayscale image of the dendrite growth on the surface of the test sample.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The present invention conducts electrochemical migration experiments on prepared test samples on an independently constructed electrochemical migration experimental platform, and uses a digital three-dimensional video microscope to monitor the surface of the test samples in real time during the electrochemical migration experiment, demonstrating the electrochemical migration process and dynamically obtaining images of the microstructure morphology changes on the surface of the test samples, providing an intuitive and visual basis for determining the location and law of dendrite growth, and effectively improving the accuracy of the prediction of metal dendrite growth evolution.

[0029] 2. The present invention uses Matlab software to perform two-dimensional grayscale conversion, contrast enhancement and noise reduction on the microstructure morphology change image of the test sample surface in sequence, thereby more accurately quantifying the spatial distribution and geometric evolution characteristics of dendrite growth; at the same time, Matlab software is used to count the parameters of the dendrite area changing with time in the two-dimensional grayscale image of dendrite growth, thereby achieving quantitative characterization of the dendrite morphology and accurately reflecting the dendrite generation, evolution distribution characteristics and morphological characteristics during the electrochemical migration process.

[0030] In summary, the present invention conducts electrochemical migration experiments on prepared test samples on an independently constructed electrochemical migration experimental platform, and monitors the test samples in the electrochemical migration experiment through a digital three-dimensional video microscope, thereby obtaining the formation of dendrites in the electrode spacing and the image of microstructure morphology changes, providing an intuitive and visual basis for determining the position and law of dendrite growth; combines Matlab software to perform two-dimensional grayscale conversion, contrast enhancement and noise reduction on the image of microstructure morphology changes on the surface of the test sample, and performs statistics on the dendrite surface area of ​​the processed two-dimensional grayscale image of dendrite growth, accurately reflecting the dendrite generation, evolution distribution characteristics and morphological characteristics during the electrochemical migration process, providing an important basis for the electrochemical migration failure mechanism in electronic devices; compared with the existing electrochemical migration failure prediction and analysis method, this method has better dynamic monitoring capability, strong real-time performance and high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Flowchart of the electrochemical migration failure prediction analysis method based on dendrite growth evolution.

[0032] Figure 2 Schematic diagram of the structure of the electrochemical migration experimental platform.

[0033] Figure 3 This is an image of the microstructure changes on the surface of the test sample in the electrochemical migration experiment.

[0034] Figure 4 This is a two-dimensional grayscale image of dendrite growth on the surface of the test sample.

[0035] Figure 5 The line graph shows the change of dendrite surface area of ​​the test sample over time. DETAILED DESCRIPTION

[0036] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0037] See also Figure 1 , a method for predicting and analyzing electrochemical migration failure based on dendrite growth evolution, comprising:

[0038] 1. Conduct an electrochemical migration experiment on the test sample on the electrochemical migration experiment platform, and monitor the microstructure morphology changes of the test sample surface during the electrochemical migration experiment using a digital 3D video microscope;

[0039] The test sample specifically includes:

[0040] like Figure 2 As shown in the figure, a copper-clad laminate is used as the substrate of the PCB board, a "Y"-shaped circuit design of the C module is adopted on the entire PCB board, and a silver plating layer with a thickness of 0.15 to 0.2 μm is deposited on the surface of two parallel copper traces of the "Y"-shaped circuit with a spacing of 0.3 to 0.6 mm through an immersion silver process to form a test sample.

[0041] In this embodiment, the test sample is prepared according to the industry specification standards. According to the test method of IPC-TM-650, the PCB board is selected as the test board of model IPC-B-25A, and the "Y"-shaped circuit design of the C module is adopted on the test board of model IPC-B-25A. The size of the entire IPC-B-25A test board is 10×11.4cm, of which the "Y"-shaped circuit board block of the C module is 25×20mm, and the substrate is an FR-4 copper-clad laminate. The surface of the copper trace is plated with 0.15um thick silver through the immersion silver process, and the spacing between two parallel copper traces is 0.3mm.

[0042] Before conducting the electrochemical migration test on the prepared test sample, it is necessary to connect the test sample to the equipment in the electrochemical migration experiment platform and check the connection of each port. Use a multimeter to test the continuity of the interconnection node of each port to eliminate the fault problem at each connection point.

[0043] The construction of the electrochemical migration experimental platform specifically includes:

[0044] like Figure 2 As shown, connect the signal output of the NI data acquisition system to the signal input of the control computer, and use the control computer to test the functional integrity of the NI data acquisition system board;

[0045] In this embodiment, the NI data acquisition system selects a multi-channel measurement system based on FlexLogger, which is mainly composed of the NI9219 data acquisition card, the NI CompactDAQ chassis, and the PC-side FlexLogger software; the NI9219 data acquisition card is a 24-bit 4-channel acquisition module, each channel contains a 6-pin spring terminal connector, the channels are independent of each other, and the connected sensors can measure different types of signals, such as temperature, strain, voltage, current and resistance signals; the NI9219 data acquisition card needs to be inserted into the NI CompactDAQ chassis to be connected to the control-end computer, so as to communicate and transmit data and display the signals of each channel in real time, and the NI9219 channels are isolated from each other to ensure the safety of the chassis, computer and each channel.

[0046] Connect the constant voltage power supply, protective resistor R0, and the two dedicated terminals of the test sample in series, and use a multimeter test lead to perform a continuity test on all interconnected nodes between the constant voltage power supply, protective resistor R0, and the two dedicated terminals of the test sample.

[0047] In this embodiment, the constant voltage power supply adopts the adjustable DC regulated power supply Wanptek NPS-W. This model is a micro-switching DC power supply with an output current of 0-10A, an output voltage of 0-30V, an output power of 300W, a display accuracy of 0.5%, and has the functions of current and voltage stabilization. The output voltage and current can be controlled and adjusted respectively by the protection resistor R0;

[0048] Connect the spring terminal connector of the NI data acquisition system to both ends of the protection resistor R0, turn on the constant voltage power supply, set the rated output voltage of the constant voltage power supply, and use a multimeter test lead to touch the electrodes of the test sample; if the absolute deviation between the voltage displayed by the multimeter and the rated output voltage of the constant voltage power supply is less than or equal to 2% of the rated output voltage of the constant voltage power supply, it indicates that all circuits of the electrochemical migration experiment platform are connected correctly and the electrochemical migration experiment platform is set up; if the absolute deviation between the voltage displayed by the multimeter and the rated output voltage of the constant voltage power supply is greater than 2% of the rated output voltage of the constant voltage power supply, it is necessary to recheck and reconnect all circuits of the electrochemical migration experiment platform.

[0049] In this embodiment, the rated output voltage of the constant voltage power supply is set to 5V. If the voltage displayed by the multimeter is between 4.900V and 5.100V (including 4.900V and 5.100V) after the electrodes of the test sample are detected by the multimeter test pen, it indicates that all circuit connections of the electrochemical migration experiment platform are correct and subsequent electrochemical migration experiments can be carried out.

[0050] The electrochemical migration experiment is performed on the test sample on the electrochemical migration experiment platform, and the image of the microstructure morphology change of the test sample surface during the electrochemical migration experiment is monitored by a digital three-dimensional video microscope, specifically including:

[0051] The test sample was removed from the circuit of the electrochemical migration experiment platform and rinsed with deionized water. After the electrode surface of the test sample was air-dried, the test sample was connected back to the circuit of the electrochemical migration experiment platform and the NI data acquisition system was turned on. Due to the extremely fast electrochemical migration rate of silver, the data monitoring and recording functions of the NI data acquisition system needed to be turned on in advance to avoid missing the voltage and current change information during the initial electrochemical migration stage.

[0052] Place the test sample connected to the circuit under a digital 3D video microscope, press the test sample tightly with a glass slide, and then use a pipette to drip electrolyte onto the electrode surface of the test sample;

[0053] In this embodiment, the digital 3D video microscope used is the HIROX RX-100 ultra-depth-of-field 3D microscope. This device features 360-degree dynamic rotation and supports viewing angle adjustment from 25° to 55°, allowing the dendrite growth process to be captured from multiple angles without moving the test specimen. The microscope's continuous optical zoom and automatic calibration system automatically adjust the scale at different magnifications, facilitating accurate measurement of dendrite dimensions. A high-precision automatic Z-axis motor and multi-layer overlay technology enable the microscope to synthesize clear images across the entire focal depth, which is crucial for observing and analyzing the microstructure and morphological characteristics of dendrites. The microscope also features a multi-layer 3D depth-of-focus synthesis function. By capturing and synthesizing images from different focal planes, it can produce clear images of the entire focal range, which is crucial for observing the dynamic growth and morphological evolution of dendrites during electrochemical migration. The RX-100's 2D and 3D cross-sectional view functions provide cross-sectional views, helping to better understand and analyze dendrite height and depth information. In addition, the digital 3D video microscope's automatic correction of position offset helps maintain image consistency and accuracy during long-term observation.

[0054] Turn on the constant voltage power supply, use the NI data acquisition system to monitor the current I and voltage U at both ends of the protection resistor R0 in real time, and use the digital three-dimensional video microscope to observe the formation of dendrites in the electrode spacing of the test sample in real time, and simultaneously obtain the image of the microstructure change of the test sample surface and transmit it to the control end computer; wait until the current I reaches the threshold current I maxThis marks the completion of the entire electrochemical migration experiment. In addition, a digital 3D video microscope is used to observe whether the deionized water between the electrodes of the test sample has evaporated. If the deionized water has completely evaporated, it also marks the completion of the electrochemical migration experiment.

[0055] In the electrochemical migration experiment of this embodiment, due to the high humidity and high voltage conditions, metal deposits form on the surface between the electrodes of the test sample, causing the conduction state between the electrodes to change over time. When the metal deposits grow from the cathode side to the anode surface, the two electrodes are connected. By observing the changes in the current I of the constant resistor R0, the evolution of the dendrite can be obtained, and the electrochemical migration failure time can be obtained. According to Ohm's law, the relationship between the constant resistor R0 and the current I is:

[0056]

[0057] Where, I max represents the threshold current, and U is the voltage across the electrodes of the test sample. When the electrodes of the test sample are in the on state, the threshold current I can be calculated and determined based on the applied voltage. max , when the measured current value is the threshold current I max When the voltage load is stopped,

[0058] Figure 3 This is an image of the microstructural morphology changes on the surface of the test sample in an electrochemical migration experiment under a digital three-dimensional video microscope. The upper boundary is the cathode and the lower boundary is the anode. As voltage is applied to the two electrode ends, the liquid film rapidly spreads, and extremely small bubbles are generated at the cathode. After repeated experiments, it was found that if dendrites form on the liquid film, they usually appear as a denser and diffuse structure. If dendrites form inside the liquid film, they show a clearer branch-like, tree-like, or snowflake-like structure, with more irregular growth, more branches, and a wider distribution.

[0059] Second, Matlab software was used to perform two-dimensional grayscale conversion, contrast enhancement, and noise reduction on the microstructure morphology change image of the test sample surface to obtain a two-dimensional grayscale image of the dendrite growth on the test sample surface;

[0060] The method of using Matlab software to sequentially perform two-dimensional grayscale conversion, contrast enhancement, and noise reduction on the microstructure morphology change image of the test sample surface to obtain a two-dimensional grayscale image of dendrite growth on the test sample surface specifically includes:

[0061] The RGB to grayscale function in Matlab software was used to convert the microstructure morphology change image of the test sample surface into two-dimensional grayscale;

[0062] In this embodiment, since the image of the microstructure morphology change of the test sample monitored by the digital three-dimensional video microscope is a color image (i.e., having three RGB channels), the RGB to grayscale function is called to convert the color image into a grayscale image, that is, a single-channel grayscale image is obtained by weighted average calculation of the original RGB three channels:

[0063] R=G=B=WR+VG+UB

[0064] Where W, V, and U represent weights. Research shows that humans are most sensitive to green, followed by red, and least sensitive to blue, so V > W > U. Experimental and theoretical evidence suggests that when W = 0.2989, V = 0.5870, and U = 0.1140, the RGB value of each pixel in a color image can be converted to a reasonable grayscale value, preserving the image's brightness information while removing color information, significantly reducing computational complexity and ultimately producing a two-dimensional grayscale image.

[0065] The adaptive histogram equalization function in Matlab software was used to enhance the contrast of the microstructure morphology change image after two-dimensional grayscale conversion;

[0066] In this embodiment, considering the influence of uneven illumination or low contrast, the dendrite and background colors are enhanced to highlight the main body of the dendrite under study; the image is divided into several small blocks, and histogram equalization is performed on each small block to enhance the local contrast; at the same time, a contrast limit threshold is determined to limit the number of pixels in the local histogram that are excessively concentrated in certain gray levels, thereby suppressing excessive amplification of noise; the processed image blocks are smoothly connected by bilinear interpolation to avoid the generation of blocky edges.

[0067] The Gaussian filter function and median filter function in Matlab software were used to reduce the noise of the contrast-enhanced microstructure morphology change image to obtain a two-dimensional grayscale image of the dendrite growth on the surface of the test sample.

[0068] In this embodiment, a median filter is performed on a two-dimensional image to achieve image denoising. Without blurring edges, each pixel in the image is processed using a sliding window, striking a balance between smoothing and preserving image detail. The median of the pixel values ​​within the window is assigned to the center pixel, effectively removing impulsive noise such as salt and pepper noise while effectively preserving image edge information.

[0069] like Figure 4 As shown in the figure, through the above-mentioned two-dimensional grayscale conversion, contrast enhancement and noise reduction processing, the black area of ​​the two-dimensional grayscale image of dendrite growth on the surface of the test sample becomes clearer, and the error generated when calculating the area of ​​the black area is also smaller, thereby optimizing the image quality and improving the calculation accuracy.

[0070] 3. Use Matlab software to count the dendrite surface area of ​​the two-dimensional grayscale image of dendrite growth on the surface of the test sample to obtain the dendrite distribution characteristics caused by electrochemical migration.

[0071] To explore the electrochemical migration characteristics, this paper statistically analyzed the surface area of ​​metal deposits between the electrodes of the test samples, namely the results of the change of dendrite surface area over time in Table 1:

[0072] Table 1 Statistical results of metal dendrite surface area over time

[0073]

[0074] Based on the statistical results of the metal dendrite surface area, the dendrite morphology between electrodes at different times was analyzed, and the following dendrite growth evolution distribution characteristics were obtained:

[0075] like Figure 5 As shown in the figure, in the initial stage, the dendrite area grows rapidly, with a speed of up to 0.5404 cm 2 / s. As the dendrite tip reaches the anode surface, the dendrite growth rate slows and stabilizes, and the dendrite preferentially grows from the cathode to the anode along the liquid film boundary. The above statistics on dendrite surface area accurately reflect the dendrite formation, evolution, distribution, and morphology during electrochemical migration, providing important evidence for the electrochemical migration failure mechanism in electronic devices.

[0076] In summary, compared with the existing technology:

[0077] The present invention conducts electrochemical migration experiments on the prepared test samples on an independently constructed electrochemical migration experimental platform, and monitors the surface of the test samples in the electrochemical migration experiment in real time through a digital three-dimensional video microscope, demonstrating the electrochemical migration process and dynamically obtaining images of the microstructure morphology changes on the surface of the test samples, providing an intuitive and visual basis for determining the position and law of dendrite growth, and effectively improving the accuracy of the prediction of metal dendrite growth evolution.

[0078] The present invention uses Matlab software to perform two-dimensional grayscale conversion, contrast enhancement and noise reduction on the microstructure morphology change image of the test sample surface in sequence, thereby more accurately quantifying the spatial distribution and geometric evolution characteristics of dendrite growth; at the same time, Matlab software is used to count the parameters of the dendrite area changing with time in the two-dimensional grayscale image of dendrite growth, thereby achieving quantitative characterization of the dendrite morphology and accurately reflecting the dendrite generation, evolution distribution characteristics and morphological characteristics during the electrochemical migration process.

[0079] The present invention has better dynamic monitoring capability, strong real-time performance and high accuracy.

[0080] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with this technical field within the technical scope disclosed by the present invention and within the spirit and principles of the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for predicting and analyzing electrochemical migration failure based on dendrite growth evolution, characterized by: include: Conduct electrochemical migration experiments on test samples on an electrochemical migration experimental platform, and monitor the microstructure changes on the surface of the test samples during the electrochemical migration experiment using a digital three-dimensional video microscope. Matlab software was used to perform two-dimensional grayscale conversion, contrast enhancement, and noise reduction on the microstructure morphology change image of the test sample surface to obtain a two-dimensional grayscale image of the dendrite growth on the test sample surface. Matlab software was used to count the dendrite surface area of ​​the two-dimensional grayscale image of dendrite growth on the surface of the test sample to obtain the dendrite distribution characteristics caused by electrochemical migration.

2. The electrochemical migration failure prediction and analysis method based on dendrite growth evolution according to claim 1, characterized in that: The test sample specifically includes: A copper-clad laminate was used as the substrate for the PCB board. A "Y"-shaped circuit design of the C module was adopted on the entire PCB board. A silver plating layer with a thickness of 0.15 to 0.2 μm was deposited on the surface of two parallel copper traces of the "Y"-shaped circuit with a spacing of 0.3 to 0.6 mm using an immersion silver process to form a test sample.

3. The electrochemical migration failure prediction and analysis method based on dendrite growth evolution according to claim 1, characterized in that: The construction of the electrochemical migration experimental platform specifically includes: Connect the signal output of the NI data acquisition system to the signal input of the control computer, and use the control computer to test the functional integrity of the NI data acquisition system board. Connect the constant voltage power supply, protective resistor R0, and the two dedicated terminals of the test sample in series, and use a multimeter test lead to perform a continuity test on all interconnected nodes between the constant voltage power supply, protective resistor R0, and the two dedicated terminals of the test sample. Connect the spring terminal connector of the NI data acquisition system to both ends of the protection resistor R0, turn on the constant voltage power supply, set the rated output voltage of the constant voltage power supply, and use a multimeter test lead to touch the electrodes of the test sample; if the absolute deviation between the voltage displayed by the multimeter and the rated output voltage of the constant voltage power supply is less than or equal to 2% of the rated output voltage of the constant voltage power supply, it indicates that all circuits of the electrochemical migration experiment platform are connected correctly and the electrochemical migration experiment platform is set up; if the absolute deviation between the voltage displayed by the multimeter and the rated output voltage of the constant voltage power supply is greater than 2% of the rated output voltage of the constant voltage power supply, it is necessary to recheck and reconnect all circuits of the electrochemical migration experiment platform.

4. The electrochemical migration failure prediction and analysis method based on dendrite growth evolution according to claim 1 or 3, characterized in that: The electrochemical migration experiment is performed on the test sample on the electrochemical migration experiment platform, and the image of the microstructure morphology change of the test sample surface during the electrochemical migration experiment is monitored by a digital three-dimensional video microscope, specifically including: Remove the test sample from the circuit of the electrochemical migration experiment platform and rinse it with deionized water. After the electrode surface of the test sample is air-dried, connect the test sample back to the circuit of the electrochemical migration experiment platform and turn on the NI data acquisition system. Place the test sample connected to the circuit under a digital 3D video microscope, press the test sample tightly with a glass slide, and then use a pipette to drip electrolyte onto the electrode surface of the test sample; Turn on the constant voltage power supply, use the NI data acquisition system to monitor the current I and voltage U across the protection resistor R0 in real time, and use a digital three-dimensional video microscope to observe the formation of dendrites in the electrode spacing of the test sample in real time, and simultaneously obtain the image of the microstructure change of the test sample surface and transmit it to the control end computer; when the current I across the protection resistor R0 reaches the threshold current I max This marks the completion of the entire electrochemical migration experiment.

5. The electrochemical migration failure prediction and analysis method based on dendrite growth evolution according to claim 1, characterized in that: The method of using Matlab software to sequentially perform two-dimensional grayscale conversion, contrast enhancement, and noise reduction on the microstructure morphology change image of the test sample surface to obtain a two-dimensional grayscale image of dendrite growth on the test sample surface specifically includes: The RGB to grayscale function in Matlab software was used to convert the microstructure morphology change image of the test sample surface into two-dimensional grayscale; The adaptive histogram equalization function in Matlab software was used to enhance the contrast of the microstructure morphology change image after two-dimensional grayscale conversion; The Gaussian filter function and median filter function in Matlab software were used to reduce the noise of the contrast-enhanced microstructure morphology change image to obtain a two-dimensional grayscale image of the dendrite growth on the surface of the test sample.

Images