Method and system for measuring adhesive force of OSP (organic solderability preservative)

Abstract

The invention relates to the field of film adhesive force measurement, in particular to an adhesive force measurement method and system for an OSP organic solderability preservative film, and the method comprises the steps: detecting the surface of the OSP organic solderability preservative film to be measured by using an electron microscope SEM for preliminary evaluation; independently sampling the to-be-measured OSP organic solderability preservative which passes the preliminary evaluation to obtain an OSP organic solderability preservative sample group; respectively selecting one sample from the OSP organic solderability preservative sample group, and carrying out scratch test, thermal cycle test and tensile test; the critical load obtained by the scratch test, the film layer change condition obtained by the thermal cycle test and the adhesive force strength data obtained by the tensile test are systematically and comprehensively analyzed, and by constructing a mathematical model, various data are weighted and calculated to obtain an adhesive force measured value. According to the invention, the adhesive force of the OSP organic solderability preservative is evaluated through comprehensive dimensions, and the accuracy and reliability of the measurement of the adhesive force of the OSP organic solderability preservative are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of film adhesion measurement, in particular to an OSP organic presoldering film adhesion measurement method and system. BACKGROUND

[0002] OSP (organic presoldering film) can effectively prevent copper surface from rusting, such as oxidation and sulfuration, in normal environment, and can also be quickly removed by flux in subsequent high-temperature environment, so that clean copper surface can quickly combine with molten solder to form a firm solder joint.

[0003] However, the adhesion of OSP organic presoldering film directly affects the soldering performance and service life. At present, the existing OSP organic presoldering film adhesion measurement methods have many deficiencies. For example, although the adhesive tape peeling method is relatively simple to operate, it can only qualitatively judge the adhesion, cannot accurately quantify the adhesion value, and is difficult to meet the demand for fine control of product quality; the thermal stress test method evaluates the adhesion by simulating the high-temperature environment of welding, but this method is greatly disturbed by test conditions and environmental factors, and it is difficult to accurately distinguish the different effects of thermal stress on the film layer itself and the bonding force between the film layer and the substrate, resulting in low accuracy and reliability of the measurement results.

[0004] In view of the limitations of the above-mentioned existing measurement methods, it is of urgent practical significance to develop a new method for accurately, comprehensively and reliably measuring the adhesion of OSP organic presoldering film, in order to improve product quality, optimize production process and ensure the performance stability of electronic products. SUMMARY

[0005] The present application provides an OSP organic presoldering film adhesion measurement method and system, which can accurately evaluate the adhesion of OSP organic presoldering film from multiple dimensions, effectively overcome the defects of existing measurement methods, and significantly improve the accuracy and reliability of measurement results.

[0006] The present application is achieved by the following technical solutions:

[0007] An OSP organic presoldering film adhesion measurement method is provided, which comprises the following steps:

[0008] Step S10: using an electron microscope SEM to detect the surface of the OSP organic presoldering film to be measured for preliminary evaluation;

[0009] Step S20: independently sampling the OSP organic presoldering film to be measured that passes the preliminary evaluation to obtain an OSP organic presoldering film sample group;

[0010] Step S30: select samples from the OSP organic solderability preservative film sample group for scratch test, thermal cycle test and tensile test;

[0011] Step S40: systemically analyze the critical load obtained from the scratch test, the film layer change obtained from the thermal cycle test and the adhesion strength data obtained from the tensile test, and calculate the adhesion measurement results by constructing a mathematical model and weighting processing the data.

[0012] Preferably, the step of using an electron microscope SEM to detect the surface of the OSP organic solderability preservative film to be measured in step S10 for preliminary evaluation includes:

[0013] Sample pretreatment: fix the OSP organic solderability preservative film to be measured on the SEM sample stage, which can be fixed with conductive glue or metal clips, ensure the surface of the OSP organic solderability preservative film to be flat, avoid the surface of the OSP organic solderability preservative film to be contaminated, the operation should be carried out in a clean environment and gloves should be worn, ensure the sample stage to be grounded to prevent static interference with the imaging quality;

[0014] Parameter setting: first set the magnification to 500 times (low power lens), globally scan the surface of the OSP organic solderability preservative film, locate the key detection area, such as poor film layer uniformity or suspected defect position, then gradually increase the magnification to 2000 times (high power lens) for fine detection of local details, the accelerating voltage can be set to 5-15kv, adjusted according to the conductivity of the sample to avoid charge accumulation, the working distance is set to 8-12mm to balance the resolution and depth of field, and the imaging mode is set to secondary electron mode to preferentially display the surface topography details;

[0015] Surface defect detection: scan along the surface of the film layer to detect whether there are linear or reticular cracks with a width of ≥1μm, focus on the stress concentration areas such as substrate corners and copper foil lines, detect whether there are circular or irregular holes with a diameter of ≥5μm or subcutaneous bubbles caused by coating process, which appear as surface protrusions or depressions, when the number of defects in a single field of view, i.e. in the high power lens, is ≥3 or there is a continuous crack with a length of >50μm, it is determined that there is a surface defect, the preliminary evaluation is not passed, and the OSP organic solderability preservative film is replaced until the preliminary evaluation is passed.

[0016] Preferably, in step S20, the OSP organic solderability preservative film to be measured that passes the preliminary evaluation is independently sampled to obtain an OSP organic solderability preservative film sample group, the OSP organic solderability preservative film to be measured that passes the preliminary evaluation in step S10 is sampled to an average of 5 independent samples and numbered as s1-s5 to form the OSP organic solderability preservative film sample group, wherein s1 is used for tensile test, s2 and s3 are used for thermal cycle test, and s4 and s5 are used for tensile test.

[0017] Preferably, the step S30 of selecting a sample from the OSP organic preservative film sample group for the scratch test comprises the following steps:

[0018] Device debugging and parameter setting: select a standard Rockwell diamond indenter with a tip curvature radius of 200±50 μm, ensure that the indenter is free of wear and notch, calibrate the vertical precision after installation to ensure that the deviation is ≤0.5°, set the scratch speed to 1-2 mm / min to ensure stable scratch process, set the loading rate to 0.5-1 N / s to ensure linear increase of load, select a suitable acoustic emission sensor and couple it to the sample table or device rack, adjust the gain to 40-60 dB to ensure that the weak signal of film peeling can be captured, and set the threshold to background noise+15 dB;

[0019] Sample positioning and fixing: select sample s1 from the OSP organic preservative film sample group and place it on the scratch test sample table, use a vacuum clamp or mechanical clamp to fix it, ensure that the sample surface is flat and there is no shaking, and the displacement error is ≤50 μm, mark 3-5 parallel scratch paths on the surface of sample s1, the distance between them is ≥2 mm to avoid interference between adjacent scratches, and the length of each path is 5-10 mm;

[0020] Preloading and contact confirmation: start the device to slowly approach the sample surface with the indenter, apply a pre-load of 0.1-0.3 N to ensure that the indenter is in light contact with the film layer, detect the position of the indenter through an optical microscope, adjust the scratch test sample table to align the indenter with the scratch starting point, and the error is ≤100 μm;

[0021] Scratch test and signal monitoring: the indenter moves along the scratch path at the set speed, while the load starts from 0 and increases linearly at a rate of 0.5-1 N / s, the acoustic emission sensor collects the acoustic emission signals generated by the scratch in real time, the sampling frequency is set to ≥1 MHz, the acoustic emission signal is low-intensity background noise with an amplitude of ≤50 mV, when the film layer starts to peel off, a burst high-amplitude pulse with an amplitude of ≥100 mV appears, the duration is 5-20 ms, and the frequency component changes suddenly, i.e., the main frequency changes from low to high, the signal amplitude threshold is set, when the signal amplitude exceeds the set threshold and lasts for 3 sampling points, the device automatically records the current load value, and the critical load of the OSP organic preservative film scratch test is recorded, the above test is performed on all scratch paths marked on the surface of sample s1, and the average critical load Pavg is obtained by taking the average value.

[0022] Preferably, the step S30 of selecting a sample from the OSP organic preservative film sample group for the thermal cycle test comprises the following steps:

[0023] Selection of test chamber and parameter setting: select a suitable high-low temperature alternating test chamber and set the temperature range parameter, temperature duration parameter and cycle number;

[0024] Sample installation and initial recording: Select sample s2 and sample s3 from the OSP organic solderability preservative film sample group in turn and place them in the test box for thermal cycle testing. Use an insulating support to fix them to avoid uneven heat conduction caused by direct contact between the sample and the box. Use a scanning electron microscope (SEM) to take pictures of 3-5 random areas on the sample at a magnification of 500-2000 times. Record the initial state of the film layer as a comparison benchmark.

[0025] Thermal cycle testing: Perform thermal cycle testing on sample s2 and sample s3 in turn. Start the test box and cycle it according to the heating and cooling stages. The heating stage involves setting the temperature from room temperature to a specified temperature at a specified heating rate and maintaining it for a certain period of time. The cooling stage involves cooling from the specified temperature to the target temperature at a specified cooling rate. Repeat the above heating and cooling stages.

[0026] Thermal cycle test result evaluation: After the thermal cycle testing of sample s2 and sample s3 is completed, take out the samples and let them stand at room temperature for a certain period of time to eliminate residual thermal stress. Use the SEM to take a second picture of the same areas photographed in the sample installation and initial recording step at the same magnification. Use image analysis software to overlay and compare the micrographs before and after testing. Mark the newly added or expanded areas. Record the peeling, through-cracking, and blister density data. Determine whether the sample is qualified or unqualified based on the recorded data.

[0027] Preferably, the step S30 of selecting a sample from the OSP organic solderability preservative film sample group for tensile testing comprises:

[0028] Sample preparation: Select sample s4 and sample s5 from the OSP organic solderability preservative film sample group. Use a precision cutting machine to cut sample s4 and sample s5 into 10mm x 50mm strips. Ensure that the edges are free of burrs and thermal damage. The cutting speed should be ≤5mm / s, and water cooling can be used.

[0029] Tensile tester parameter setting: Select a suitable high-precision tensile tester with a load accuracy of ±0.5% FS and a displacement accuracy of ±0.01mm. Install a flat-jaw clamp suitable for strip samples, with a surface roughness Ra≤1.6μm to prevent sample slippage. Set the tensile speed, load collection frequency, and displacement range according to the sample properties.

[0030] Sample placement: Symmetrically load the cut strip samples of sample s4 and sample s5 into the clamp, ensuring that the sample axis coincides with the center axis of the clamp with a deviation of ≤0.5mm to avoid stress concentration caused by eccentric tension. Preload an initial force of 0.1-0.2N, which should not exceed 5% of the estimated maximum load. Check whether the sample is firmly clamped and zero the load and displacement sensors to establish a test baseline.

[0031] Tensile test and data collection: start the tensile testing machine to stretch the sample at a set tensile speed, record the data and draw the tensile force (N)-elongation (mm) curve at the same time, when the sample film layer and the substrate are visually separated, such as film layer wrinkling, local peeling, record the change of curve slope, when the curve appears peak load, it indicates that the sample film layer is completely separated or the substrate is broken, immediately pause the test, record the maximum tensile force (Fmax, N) at this time, when the sample slips in the clamp during the test, that is, the load suddenly decreases by more than 20% without reaching the peak value, the data is invalid, re-clamp the sample or replace the clamp;

[0032] Adhesion calculation: calculate the adhesion according to the experimental data, as shown in formula (1):

[0033]

[0034] Wherein, F max is the maximum tensile force, S is the cross-sectional area of the strip-shaped sample, ω is the width of the strip-shaped sample, σ is the adhesion, the average value of the strip-shaped samples cut from sample s4 and sample s5, t is the thickness of the strip-shaped sample, and the average value of the strip-shaped samples cut from sample s4 and sample s5.

[0035] Preferably, the step of calculating the adhesion measurement result by constructing a mathematical model and weighting the data in the step S40 comprises:

[0036] Construction of weighted evaluation mathematical model: the weighted evaluation mathematical model is constructed as shown in formula (2):

[0037] C=W1*Pavg+W2*σ (2)

[0038] Wherein, C is the comprehensive evaluation value of adhesion, W1 is the weight of the average critical load Pavg obtained by scratch test, W2 is the weight of the adhesion σ obtained by tensile test, and W1+W2=1;

[0039] Evaluation value calculation and evaluation result: calculate the comprehensive evaluation value of adhesion according to the constructed weighted evaluation mathematical model, set the threshold value of the comprehensive evaluation value of adhesion, when the calculation result is greater than or equal to the set threshold value and the determination result of the sample in the thermal cycle test is qualified, it is determined that the OSP organic presoldering film adhesion to be measured is qualified, and the calculated comprehensive evaluation value of adhesion is output as the OSP organic presoldering film adhesion measurement value, and the rest are determined as OSP organic presoldering film adhesion to be measured.

[0040] In addition, in order to achieve the above purpose, the application also provides an OSP organic presoldering film adhesion measurement system, which comprises:

[0041] OSP organic solderability preservative film surface preliminary evaluation module: used for using an electron microscope SEM to detect the OSP organic solderability preservative film surface to be measured to perform preliminary evaluation;

[0042] OSP organic solderability preservative film sample collection module: used for independently sampling the OSP organic solderability preservative film to be measured that passes preliminary evaluation, to obtain an OSP organic solderability preservative film sample group;

[0043] OSP organic solderability preservative film adhesion comprehensive test module: used for selecting samples from the OSP organic solderability preservative film sample group to perform scratch test, thermal cycle test and tensile test;

[0044] OSP organic solderability preservative film adhesion evaluation module: used for performing systematic comprehensive analysis on critical load obtained through scratch test, film layer change condition obtained through thermal cycle test and adhesion strength data obtained through tensile test, and calculating adhesion measurement results by constructing a mathematical model and performing weighted processing on various data.

[0045] In addition, to achieve the above object, the application further provides an OSP organic solderability preservative film adhesion measurement device, which comprises a memory, a processor, and an OSP organic solderability preservative film adhesion measurement algorithm and the like program stored on the memory and capable of running on the processor.

[0046] In addition, to achieve the above object, the application further provides a computer program product, which comprises an OSP organic solderability preservative film adhesion measurement algorithm and the like program, and the OSP organic solderability preservative film adhesion measurement algorithm and the like program is executed by a processor to realize an OSP organic solderability preservative film adhesion measurement method as described above.

[0047] The application has the following advantages and effects:

[0048] The OSP organic solderability preservative film adhesion measurement method and system provided by the application can effectively make up for the limitation of a single measurement method, greatly improve the accuracy and reliability of measurement results, and realize quantitative evaluation of OSP organic solderability preservative film adhesion by innovatively integrating various test methods and measuring and evaluating OSP organic solderability preservative film adhesion from different angles. BRIEF DESCRIPTION OF DRAWINGS

[0049] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0050] Figure 1 A flow chart of an OSP organic presoldering film adhesion force measurement method of the present application.

[0051] Figure 2 A structural schematic diagram of an OSP organic presoldering film adhesion force measurement system of the present application.

[0052] Figure 3 A structural schematic block diagram of an OSP organic presoldering film adhesion force measurement electronic device of the present application. DETAILED DESCRIPTION

[0053] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments only constitute some embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0054] As shown in Figure 1 an embodiment of the present application, an OSP organic presoldering film adhesion force measurement method comprises the following steps:

[0055] Step S10: using an electron microscope SEM to detect the surface of the OSP organic presoldering film to be measured for preliminary evaluation.

[0056] Specifically, the step of using an electron microscope SEM to detect the surface of the OSP organic presoldering film to be measured for preliminary evaluation in step S10 comprises:

[0057] Sample pretreatment: fixing the OSP organic presoldering film to be measured on a SEM sample table, which can be fixed using conductive glue or a metal clamp, ensuring that the surface of the OSP organic presoldering film is flat and avoiding contamination of the surface of the OSP organic presoldering film, the operation needing to be performed in a clean environment and wearing gloves, ensuring that the sample table is grounded to prevent static interference with the imaging quality;

[0058] Parameter setting: first set the magnification to 500 times (low magnification), globally scan the OSP organic solderability preservative film surface, locate the key detection area, such as the film layer uniformity is poor or suspected defect site, then gradually increase the magnification to 2000 times (high magnification), fine detection of local details, the accelerating voltage can be set to 5-15kv, adjust according to the sample conductivity, avoid charge accumulation, the working distance is set to 8-12mm, balance the resolution and depth of field, the imaging mode is set to secondary electron mode, preferentially display the surface topography details;

[0059] Surface defect detection: scan along the film layer surface, detect whether there are linear or network cracks, width≥1μm, pay attention to the stress concentration area such as substrate corner and copper foil lines, detect whether there are circular or irregular holes on the film layer surface, diameter≥5μm, or subcutaneous bubbles caused by coating process, which are manifested as surface protrusions or depressions, when the number of defects in a single field of view, i.e. high magnification, is≥3, or there is a continuous crack with a length>50μm, it is determined that there is a surface defect, preliminary evaluation fails, replace the OSP organic solderability preservative film until the preliminary evaluation passes.

[0060] Step S20: independently sampling the OSP organic solderability preservative film to be measured which passes the preliminary evaluation to obtain an OSP organic solderability preservative film sample group.

[0061] Specifically, in step S20, the OSP organic solderability preservative film to be measured which passes the preliminary evaluation is independently sampled to obtain an OSP organic solderability preservative film sample group, the OSP organic solderability preservative film to be measured which passes the preliminary evaluation in step S10 is sampled to 5 independent samples on average and numbered as s1-s5 to form the OSP organic solderability preservative film sample group, wherein s1 is used for tensile test, s2 and s3 are used for thermal cycle test, and s4 and s5 are used for tensile test.

[0062] Step S30: selecting samples from the OSP organic solderability preservative film sample group for scratch test, thermal cycle test and tensile test.

[0063] Specifically, in step S30, the step of selecting samples from the OSP organic solderability preservative film sample group for scratch test includes:

[0064] Device calibration and parameter setting: select a standard Rockwell diamond indenter with a tip radius of 200 ± 50 μm, ensure that the indenter is free of wear and damage, calibrate the vertical accuracy after installation to ensure that the deviation is ≤ 0.5°, set the scratch speed to 1-2 mm / min, for example 1.5 mm / min, ensure that the scratch process is stable, set the loading rate to 0.5-1 N / s, for example 0.8 N / s, ensure that the load increases linearly, select a suitable acoustic emission sensor and couple it to the sample table or device rack, adjust the gain to 40-60 dB to ensure that the weak signal of the film layer peeling can be captured, and set the threshold to background noise + 15 dB;

[0065] Sample positioning and fixing: select sample s1 from the OSP organic solderability preservative film sample group and place it on the scratch test sample table, use a vacuum clamp or mechanical clamp to fix it, ensure that the sample surface is flat and does not shake, and the displacement error is ≤ 50 μm, mark 3-5 parallel scratch paths on the surface of sample s1, the distance between adjacent scratches is ≥ 2 mm to avoid interference between adjacent scratches, and the length of each path is 5-10 mm;

[0066] Preloading and contact confirmation: start the device to slowly approach the sample surface with the indenter, apply a pre-load of 0.1-0.3 N to ensure that the indenter is in light contact with the film layer, detect the position of the indenter through an optical microscope, adjust the scratch test sample table to align the indenter with the scratch starting point, and the error is ≤ 100 μm;

[0067] Scratch test and signal monitoring: the indenter moves along the scratch path at the set speed, and the load increases linearly at a rate of 0.5-1 N / s starting from 0, the acoustic emission sensor collects the acoustic emission signals generated by the scratch in real time, the sampling frequency is set to ≥ 1 MHz, the acoustic emission signal is a low-intensity background noise with an amplitude of ≤ 50 mV, when the film layer starts to peel off, a burst of high-amplitude pulses with an amplitude of ≥ 100 mV appears, the duration is 5-20 ms, and the frequency component changes suddenly, i.e., the main frequency changes from low to high, the signal amplitude threshold is set, when the signal amplitude exceeds the set threshold and lasts for 3 sampling points, about 3 μs, the device automatically records the current load value, and the value is recorded as the critical load of the OSP organic solderability preservative film scratch test, the above test is performed on all scratch paths marked on the surface of sample s1, and the average critical load Pavg is obtained by taking the average value. For example, the sample is firmly fixed on the workbench of the scratch tester, a diamond indenter with a tip radius of 200 μm is used for scratch testing, a straight line is scratched on the surface of the film layer at a speed of 1 mm / min, the loading force starts from 0 and gradually increases at a rate of 0.5 N / s, when the loading force reaches 12 N, the acoustic emission sensor detects that the acoustic emission signal changes significantly, and the recorded 12 N is the critical load when the film layer peels off.

[0068] Specifically, the step of selecting a sample from the OSP organic solderability preservative film sample group for thermal cycle testing in step S30 includes:

[0069] Experiment box selection and parameter setting: select a suitable high-low temperature alternating test box, and set the temperature range parameter, temperature duration parameter and cycle number, such as setting the temperature range to -40°C to 125°C, the holding time at each temperature point to 30 minutes, and the cycle number to 5 times;

[0070] Sample installation and initial recording: samples s2 and s3 are selected from the OSP organic solderability preservative film sample group and are placed in the experiment box in turn for thermal cycle testing, and an insulating support is used for fixation to avoid uneven heat conduction caused by direct contact between the sample and the box. A scanning electron microscope (SEM) is used to take pictures of 3-5 random areas of the sample at a magnification of 500-2000 times, and the initial state of the film layer, such as whether there are microcracks, interface bonding conditions, etc., is recorded as a comparison benchmark.

[0071] Thermal cycle testing: samples s2 and s3 are subjected to thermal cycle testing in turn. The experiment box is started, and the temperature is cycled according to the heating stage and the cooling stage. The heating stage is from room temperature, such as 25°C, to a set temperature, such as 125°C, at a set heating rate, and is maintained for a certain time, such as 30 minutes. The cooling stage is from the set temperature to the target temperature, such as from 125°C to -40°C at a set cooling rate, and is maintained for 30 minutes. The above heating and cooling stages are repeated, such as 5 times. The total testing time is about 5x2x30 minutes + (heating and cooling time x 5) ≈ 6.5-8 hours, depending on the heating and cooling efficiency of the equipment. The temperature and humidity in the box are monitored in real time during the test. When the temperature exceeds the limit, i.e., the deviation is > ±3°C, an abnormal alarm is given, the test is immediately paused, and the fault is checked. After the fault is eliminated, the test needs to be restarted from the initial temperature.

[0072] Thermal cycle test result evaluation: after the thermal cycle test of samples s2 and s3 is completed, the samples are taken out and left to stand at room temperature for a certain time, such as 30 minutes, to eliminate residual thermal stress. The same areas photographed in the sample installation and initial recording step are photographed again using SEM at the same magnification. Through image analysis software, such as ImageJ, the pre-test and post-test microscopic images are superimposed and compared, the new or expanded areas are marked, the peeling, penetrating crack and blister density data are recorded, and the sample is determined to be qualified or unqualified according to the recorded data, for example, if there is no obvious peeling (peeling area <0.01 mm 2The sample is placed in a high-low temperature alternating test chamber, and thermal cycle test is carried out strictly according to the set temperature range (-40 DEG C to 125 DEG C) and cycle number (5 times), each temperature point is kept for 30 minutes, after the test is completed, the sample surface is detected again using a scanning electron microscope, it is found that the film layer does not appear peeling, blistering and other abnormal phenomena, which indicates that the adhesion performance of the film layer under the action of thermal stress is good.

[0073] Specifically, the step of selecting a sample from the OSP organic presoldering film sample group for tensile testing in step S30 includes:

[0074] Sample preparation: select sample s4 and sample s5 from the OSP organic presoldering film sample group, cut sample s4 and sample s5 into 10 mm x 50 mm strips using a precision cutting machine, ensure that the edges are free of burrs and thermal damage, the cutting speed is ≤5 mm / s, and water cooling can be used;

[0075] Tensile tester parameter setting: select a suitable high-precision tensile tester, load accuracy ±0.5% FS, displacement accuracy ±0.01 mm, install a flat-jaw clamp suitable for strip-shaped samples, the surface roughness Ra of the clamp is ≤1.6 μm, to avoid sample slipping, set the tensile speed, load acquisition frequency and displacement range according to the sample properties, for example, set the tensile speed to 1 mm / min, constant rate to avoid inertial force, load acquisition frequency to ≥10 Hz, and displacement range to 0-50 mm;

[0076] Sample placement: symmetrically load the strip-shaped samples cut from sample s4 and sample s5 into the clamp, ensure that the sample axis coincides with the center axis of the clamp, the deviation is ≤0.5 mm, avoid stress concentration caused by eccentric stretching, pre-load an initial force of 0.1-0.2 N, which is not more than 5% of the estimated maximum load, check whether the sample is clamped firmly, and at the same time, zero the load and displacement sensors to establish the test reference;

[0077] Tensile testing and data acquisition: start the tensile tester, stretch the sample at the set tensile speed, record the data and draw the tensile force (N)-elongation (mm) curve, when the sample film layer and the substrate appear visible separation, such as film layer wrinkling, local peeling, record the change of curve slope, when the curve appears peak load and then drops sharply, indicating that the sample film layer is completely separated or the substrate is broken, immediately pause the test, record the maximum tensile force (Fmax, N) at this time, when the sample slips in the clamp during the test, i.e. the load suddenly decreases by >20% without reaching the peak value, the data is invalid, the sample is re-clamped or the clamp is replaced;

[0078] Adhesion force calculation: The magnitude of the adhesion force is calculated based on the experimental data, as shown in equation (1):

[0079]

[0080] Among them, F max Here, S is the maximum tensile force, ω is the cross-sectional area of ​​the strip sample, σ is the width of the strip sample, σ is the adhesion force (the average of the strips cut from samples s4 and s5), and t is the thickness of the strip sample (the average of the strips cut from samples s4 and s5). For example, the sample is cut into 10mm × 50mm strips, and a tensile test is performed using a tensile testing machine at a speed of 1mm / min. When the OSP organic solder mask separates from the substrate, the maximum tensile force at this point is recorded as 15N. This is based on the cross-sectional area of ​​the sample (10mm × 1mm = 10mm²). 2 The adhesion strength between the film and the substrate was calculated to be 1.5 N / mm².

[0081] Step S40: The critical load obtained from the scratch test, the film layer change obtained from the thermal cycling test, and the adhesion strength data obtained from the tensile test are systematically analyzed. By constructing a mathematical model, the data are weighted and calculated to obtain the adhesion measurement results.

[0082] Specifically, step S40, which involves constructing a mathematical model and weighting the data to calculate the adhesion measurement result, includes:

[0083] Constructing a weighted evaluation mathematical model: The weighted evaluation mathematical model is constructed as shown in equation (2):

[0084] C=W1×Pavg+W2×σ (2)

[0085] Where C is the comprehensive adhesion evaluation value, W1 is the weight of the average critical load Pavg obtained from the scratch test, W2 is the weight of the adhesion magnitude σ obtained from the tensile test, and W1+W2=1.

[0086] Evaluation value calculation and evaluation results: The comprehensive adhesion evaluation value is calculated based on the constructed weighted evaluation mathematical model. For example, if W1 = 0.4 and W2 = 0.6, the comprehensive adhesion evaluation value is 0.4Pavg + 0.6σ. A threshold for the comprehensive adhesion evaluation value is set. When the calculated result is greater than or equal to the set threshold and the judgment result in the thermal cycling test of the sample is qualified, the adhesion of the OSP organic solder mask to be measured is determined to be qualified, and the calculated comprehensive adhesion evaluation value is output as the measured adhesion value of the OSP organic solder mask. In other cases, the adhesion of the OSP organic solder mask to be measured is determined to be unqualified.

[0087] In addition, as Figure 2 In one embodiment of the present application, a system for measuring the adhesion of OSP organic solderability preservative film is provided, which comprises:

[0088] An OSP organic solderability preservative film surface preliminary evaluation module is configured to use a scanning electron microscope (SEM) to detect the surface of the OSP organic solderability preservative film to be measured and perform preliminary evaluation.

[0089] An OSP organic solderability preservative film sample collection module is configured to independently sample the OSP organic solderability preservative film to be measured that passes the preliminary evaluation to obtain a sample group of OSP organic solderability preservative film.

[0090] An OSP organic solderability preservative film adhesion comprehensive test module is configured to select samples from the sample group of OSP organic solderability preservative film for scratch test, thermal cycle test, and tensile test.

[0091] An OSP organic solderability preservative film adhesion evaluation module is configured to comprehensively analyze the critical load obtained by the scratch test, the film layer change obtained by the thermal cycle test, and the adhesion strength data obtained by the tensile test, and calculate the adhesion measurement result by constructing a mathematical model and performing weighted processing on the data.

[0092] The system for measuring the adhesion of OSP organic solderability preservative film provided in the present application adopts the method for measuring the adhesion of OSP organic solderability preservative film in the above-mentioned embodiments, and can solve the technical problem of low accuracy of conventional OSP organic solderability preservative film adhesion test. Compared with the prior art, the system for measuring the adhesion of OSP organic solderability preservative film provided in the present application has the same beneficial effects as the method for measuring the adhesion of OSP organic solderability preservative film provided in the above-mentioned embodiments, and other technical features in the system for measuring the adhesion of OSP organic solderability preservative film are the same as the features disclosed in the above-mentioned embodiments, which will not be repeated here.

[0093] The present application provides a system for measuring the adhesion of OSP organic solderability preservative film, which comprises at least one processor and a memory in communication with the at least one processor, wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method for measuring the adhesion of OSP organic solderability preservative film in Embodiment I.

[0094] As Figure 3As shown, in one embodiment of the present application, a structural diagram of an OSP organic solderability preservative film adhesion measuring device suitable for implementing embodiments of the present application is shown. The OSP organic solderability preservative film adhesion measuring device in embodiments of the present application can include, but is not limited to, mobile terminals such as mobile phones, notebook computers, digital broadcast receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Descriptions), PMPs (Portable Media Players), and the like, as well as fixed terminals such as digital TVs, desktop computers, and the like. Figure 3 The OSP organic solderability preservative film adhesion measuring device shown is merely one example, and should not impose any limitations on the functions and use ranges of embodiments of the present application.

[0095] Figure 3 The OSP organic solderability preservative film adhesion measuring device shown can include a processing system 1001 (e.g., a central processor, a graphics processor, etc.) that can perform various appropriate actions and processes according to programs stored in a read only memory (ROM) 1002 or programs loaded from a storage system 1003 into a random access memory (RAM) 1004. Various programs and data required for operation of the OSP organic solderability preservative film adhesion measuring device are also stored in the RAM 1004. The processing system 1001, the ROM 1002, and the RAM 1004 are connected to each other through a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. In general, the following systems can be connected to the I / O interface 1006: an input system 1007 including, for example, a touch screen, a touch pad, a keyboard, a mouse, an image sensor, a microphone, an accelerometer, a gyroscope, and the like; an output system 1008 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, and the like; the storage system 1003 including, for example, a magnetic tape, a hard disk, and the like; and a communication system 1009. The communication system 1009 can allow the OSP organic solderability preservative film adhesion measuring device to communicate wirelessly or by wire with other devices to exchange data. Although the OSP organic solderability preservative film adhesion measuring device having various systems is shown in the figure, it should be understood that all of the systems shown are not required to be implemented or provided. More or fewer systems can be alternatively implemented or provided.

[0096] In particular, according to the embodiments disclosed in the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, the embodiments disclosed in the present application include a computer program product comprising a computer program carried on a computer readable medium, the computer program containing program code for executing the method shown in the flowchart. In such embodiments, the computer program can be downloaded and installed from a network through a communication system, or installed from the storage system 1003, or installed from the ROM 1002. When the computer program is executed by the processing system 1001, the above-mentioned functions defined in the method of the embodiments disclosed in the present application are executed.

[0097] The OSP organic solderability preservative film adhesion force measuring device provided by the present application adopts the OSP organic solderability preservative film adhesion force measuring method in the above-mentioned embodiments, and can solve the technical problem of low accuracy of traditional OSP organic solderability preservative film adhesion force testing. Compared with the prior art, the OSP organic solderability preservative film adhesion force measuring device provided by the present application has the same beneficial effects as the OSP organic solderability preservative film adhesion force measuring method provided by the above-mentioned embodiments, and other technical features in the OSP organic solderability preservative film adhesion force measuring device are the same as the features disclosed in the previous embodiment method, which will not be repeated here.

[0098] Portions of the present application can be realized in hardware, software, firmware, or a combination thereof. In the description above, specific features, structures, materials or characteristics can be combined in any suitable manner based on the general understanding of those skilled in the art.

[0099] The present application also provides a computer program product comprising a computer program which, when executed by a processor, implements the steps of the OSP organic solderability preservative film adhesion force measuring method as described above.

[0100] The computer program product provided by the present application can solve the technical problem of low accuracy of traditional OSP organic solderability preservative film adhesion force testing. Compared with the prior art, the computer program product provided by the present application has the same beneficial effects as the OSP organic solderability preservative film adhesion force measuring method provided by the above-mentioned embodiments, which will not be repeated here.

[0101] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A method of measuring the adhesion of OSP organic solderability preservatives film, characterized by, The method comprises the following steps: Step S10: using an electron microscope SEM to detect the surface of the OSP organic solderability preservative film to be measured for preliminary evaluation; Step S20: independently sampling the OSP organic solderability preservative film that passes the preliminary evaluation to obtain an OSP organic solderability preservative film sample group; Step S30: selecting samples from the OSP organic solderability preservative film sample group for scratch testing, thermal cycle testing and tensile testing; Step S40: comprehensively analyzing the critical load obtained by the scratch testing, the film layer change obtained by the thermal cycle testing and the adhesion strength data obtained by the tensile testing, and calculating the adhesion measurement result by constructing a mathematical model and performing weighted processing on the data.

2. The OSP organic presolder film adhesion force measurement method according to claim 1, characterized by, The step S10 of using an electron microscope SEM to detect the surface of the OSP organic solderability preservative film to be measured for preliminary evaluation comprises: Sample pretreatment: fixing the OSP organic solderability preservative film to be measured on the SEM sample stage to ensure that the surface of the OSP organic solderability preservative film is flat; Parameter setting: first set the magnification to 500 times, globally scan the surface of the OSP organic solderability preservative film, and then gradually increase the magnification to 2000 times to detect the local details; Surface defect detection: scan along the film layer surface to detect whether there are linear or reticular cracks, whether there are circular or irregular holes or subcutaneous bubbles caused by the coating process on the film layer surface, which are manifested as surface protrusions or depressions, and when the number of defects in a single field of view is ≥3 or there is a continuous crack with a length >50 μm, it is determined that there are surface defects and the preliminary evaluation fails, and the OSP organic solderability preservative film is replaced until the preliminary evaluation passes.

3. The OSP organic presolder film adhesion force measurement method according to claim 1, characterized by, In the step S20, the OSP organic solderability preservative film that passes the preliminary evaluation is independently sampled to obtain an OSP organic solderability preservative film sample group, the OSP organic solderability preservative film to be measured that passes the preliminary evaluation in step S10 is sampled to obtain 5 independent samples, which are numbered as s1-s5 to form the OSP organic solderability preservative film sample group, wherein s1 is used for tensile testing, s2 and s3 are used for thermal cycle testing, and s4 and s5 are used for tensile testing.

4. The OSP organic presolder film adhesion force measurement method according to claim 1, characterized by, The step S30 of selecting samples from the OSP organic solderability preservative film sample group for scratch testing comprises: Device debugging and parameter setting: adopt a standard Rockwell diamond indenter with a tip curvature radius of 200±50 μm to ensure that the indenter is free of wear and notch, calibrate the vertical precision after installation to make the deviation ≤0.5°, set the scratch speed to 1-2 mm / min, set the loading rate to 0.5-1 N / s, and couple an acoustic emission sensor to the sample stage or the equipment rack; Sample positioning and fixing: select sample s1 from the OSP organic solderability preservative film sample group and place it on the scratch test sample stage, fix it with a vacuum clamp or a mechanical clamp to ensure that the sample surface is flat and free of shaking, and the displacement error is ≤50 μm, and mark 3-5 parallel scratch paths on the surface of sample s1; Preloading and contact confirmation: start the equipment to make the indenter approach the sample surface, apply a pre-load of 0.1-0.3 N, detect the position of the indenter through an optical microscope, and adjust the scratch test sample stage to make the indenter align with the scratch starting point; Scratch test and signal monitoring: the indenter moves along the scratch path at a set speed, while the load linearly increases from 0 at a rate of 0.5-1 N / s, the acoustic emission sensor collects the acoustic signals generated by the scratch in real time, the sampling frequency is set to ≥1 MHz, and the signal amplitude threshold is set, when the signal amplitude exceeds the set threshold and lasts for 3 sampling points, the device automatically records the current load value, and the average critical load of the OSP organic solderability preservative film scratch test is recorded.

5. The OSP organic solderability preservative adhesion force measurement method of claim 1, wherein, The step S30 of selecting samples from the OSP organic solderability preservative film sample group for thermal cycle test comprises: Selection of test chamber and parameter setting: select a suitable high-low temperature alternating test chamber, and set the temperature range parameter, temperature duration parameter and cycle number; Sample installation and initial recording: select sample s2 and sample s3 from the OSP organic solderability preservative film sample group, and install them in the test chamber for thermal cycle test, use an insulating support to fix, use a scanning electron microscope (SEM) to take pictures of 3-5 random areas on the sample surface, with a magnification of 500-2000 times, record the initial state of the film layer as a comparison reference; Thermal cycle test: thermal cycle test is performed on sample s2 and sample s3 in turn, the test chamber is started, and the temperature is raised and lowered in turn, the temperature is raised from room temperature to a set temperature at a set rate, and then kept for a certain period of time, the temperature is lowered from the set temperature to the target temperature at a set rate, and the above steps are repeated; Evaluation of thermal cycle test results: after the thermal cycle test of sample s2 and sample s3 is completed, the samples are taken out and placed at room temperature for a certain period of time, the same areas photographed in the sample installation and initial recording step are photographed again using SEM, the magnification is consistent, the microscopic images before and after the test are superimposed and compared through image analysis software, the newly increased or expanded areas are marked, the peeling, penetrating crack and blister density data are recorded, and the sample is determined to be qualified or unqualified according to the recorded data.

6. The OSP organic solderability preservative adhesion force measurement method of claim 1, wherein, The step S30 of selecting samples from the OSP organic solderability preservative film sample group for tensile test comprises: Sample preparation: select sample s4 and sample s5 from the OSP organic solderability preservative film sample group, and cut sample s4 and sample s5 into 10 mm×50 mm strips using a cutting machine; Tensile testing machine parameter setting: select a suitable tensile testing machine, install a flat-jaw clamp suitable for strip-shaped samples, and set the tensile speed, load acquisition frequency and displacement range according to the sample properties; Sample placement: symmetrically load the strip-shaped samples cut from sample s4 and sample s5 into the clamp, pre-load an initial force of 0.1-0.2 N, check whether the sample is clamped firmly, and clear the load and displacement sensors to establish the test reference; Tensile test and data collection: start the tensile testing machine to stretch the sample at a set tensile speed, record the data and draw the tensile force-elongation curve at the same time, when the sample film layer and the substrate are visually separated, record the change of the curve slope, when the curve appears peak load and then drops, immediately pause the test, record the maximum tensile force at this time, when the sample slips in the clamp during the test, the data is invalid, re-clamp the sample or replace the clamp; Adhesion force calculation: calculate the adhesion force according to the experimental data, as shown in formula (1): where F is the maximum tensile force, S is the cross-sectional area of the strip sample, ω is the width of the strip sample, σ is the adhesion strength, t is the thickness of the strip sample, and the average values of the strip samples cut from the sample s4 and the sample s5 are taken. max where F is the maximum tensile force, S is the cross-sectional area of the strip sample, ω is the width of the strip sample, σ is the adhesion strength, t is the thickness of the strip sample, and the average values of the strip samples cut from the sample s4 and the sample s5 are taken.

7. The OSP organic solderability preservative adhesion force measurement method of claim 1, wherein, The step S40 of calculating the adhesion force measurement result by constructing a mathematical model and weighting the data includes: Construction of weighted evaluation mathematical model: the weighted evaluation mathematical model is constructed as shown in formula (2): C=W1×Pavg+W2×σ (2) Wherein, C is the comprehensive evaluation value of adhesion force, W1 is the weight of the average critical load Pavg obtained by scratch test, W2 is the weight of the adhesion force σ obtained by tensile test, and W1+W2=1; Evaluation value calculation and evaluation result: calculate the comprehensive evaluation value of adhesion force according to the constructed weighted evaluation mathematical model, set the threshold value of the comprehensive evaluation value of adhesion force, when the calculation result is greater than or equal to the set threshold value and the determination result of the sample in the thermal cycle test is qualified, it is determined that the OSP organic solderability preservative film adhesion force to be measured is qualified, and the calculated comprehensive evaluation value of adhesion force is output as the OSP organic solderability preservative film adhesion force measurement value, and the rest are determined as unqualified OSP organic solderability preservative film adhesion force to be measured.

8. An OSP organic solderability preservative film adhesion measurement system characterized by, The adhesion force measurement system of the OSP organic solderability preservative film includes: OSP organic solderability preservative film surface preliminary evaluation module: used for detecting the surface of the OSP organic solderability preservative film to be measured by using an electron microscope SEM for preliminary evaluation; OSP organic solderability preservative film sample collection module: used for independently sampling the OSP organic solderability preservative film to be measured which passes the preliminary evaluation to obtain an OSP organic solderability preservative film sample group; OSP organic solderability preservative film adhesion force comprehensive test module: used for selecting samples from the OSP organic solderability preservative film sample group for scratch test, thermal cycle test and tensile test; OSP organic solderability preservative film adhesion force evaluation module: used for systemically analyzing the critical load obtained by scratch test, the film layer change obtained by thermal cycle test and the adhesion strength data obtained by tensile test, and calculating the adhesion force measurement result by constructing a mathematical model and weighting the data.

9. An OSP organic solderability preservative film adhesion measuring apparatus characterized by, The adhesion force measurement system of the OSP organic solderability preservative film includes: A memory, a processor and an OSP organic solderability preservative film adhesion force measurement program stored on the memory and executable on the processor, when the OSP organic solderability preservative film adhesion force measurement program is executed by the processor, the OSP organic solderability preservative film adhesion force measurement method of any one of claims 1 to 7 is realized.

10. A computer program product, characterised in that, The computer program product comprises an OSP organic presoldering film adhesion force measuring program, and the OSP organic presoldering film adhesion force measuring program realizes the OSP organic presoldering film adhesion force measuring method as claimed in any one of claims 1 to 7 when executed by the processor.

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