Ultrasonic detection method, system and device for integrated circuit plastic package

Abstract

The invention relates to the technical field of ultrasonic detection, in particular to an ultrasonic detection method, system and device for integrated circuit plastic package. The method comprises the following steps: analyzing a distribution suspected index from a distribution position according to a proportion of a suspected defect area in an ultrasonic detection image of each sample and distance distribution of the suspected defect area and a module area, and analyzing an air hole characteristic index from internal distribution similarity in combination with a similar condition of ultrasonic signal fluctuation between pixel points in the area; obtaining a pore defect possible index; and correcting the air hole defect possible indexes by combining the overlapping expression of the suspected defect areas among the plurality of ultrasonic detection images, and obtaining the corrected possible indexes for air hole detection. According to the method, through the similarity characterization degree and the overlapping distribution degree of the defect features in the defect areas among the ultrasonic detection images of the multiple samples, the distinguishing accuracy of the electromagnetic noise and the pore defects is improved, the defect detection is more accurate, and then the optimization reliability of subsequent process parameters is improved.

Description

Technical Field

[0001] The present invention relates to the field of ultrasonic detection technology, and in particular to an ultrasonic detection method, system and device for integrated circuit plastic packaging. Background Art

[0002] The purpose of packaging integrated circuits is to provide a stable and reliable working environment for the chip to prevent the integrated circuit from being affected by the external environment and affecting its service life, such as dust, moisture, static electricity, etc. The integrated circuit plastic packaging process is the stage in the entire integrated circuit plastic packaging process where internal defects are most likely to occur. Optical detection methods can only detect surface defects. Therefore, ultrasonic detection methods are needed to obtain internal defect images of integrated circuit plastic packaging through the packaging material.

[0003] At present, for integrated circuit plastic packaging ultrasonic testing, it is necessary to determine the type of defects based on the test image and establish a mapping relationship between the defects and the packaging process parameters, thereby obtaining the optimal process parameters for integrated circuit packaging and improving the availability of integrated circuits.

[0004] Due to the precision of integrated circuit devices, the electromagnetic components inside the ultrasonic testing equipment emit electromagnetic waves during normal operation. The electromagnetic waves are received by the ultrasonic testing equipment, thereby interfering with the normal operation of the ultrasonic equipment and causing electromagnetic noise to appear in the ultrasonically tested integrated circuit plastic package image. Slight changes in packaging parameters will lead to defects in the packaging process. Porosity defects are a common type of packaging defects. Internal pores or voids that appear after integrated circuit packaging will cause the ultrasonic image to have an image that is similar to electromagnetic noise, affecting the judgment of the real pore defects of the integrated circuit plastic package, making the defect detection results inaccurate, and further affecting the subsequent corresponding judgment of defects and process parameters, making the judgment and selection of process parameters inaccurate. Summary of the invention

[0005] In order to solve the technical problem that the internal pores or voids defects appearing after integrated circuit packaging in the prior art will cause the ultrasonic image to have an image performance similar to electromagnetic noise, which affects the judgment of the real pore defects and makes the defect detection result inaccurate, the purpose of the present invention is to provide an ultrasonic detection method, system and device for integrated circuit plastic packaging, and the technical scheme adopted is as follows: The present invention provides an ultrasonic detection method for integrated circuit plastic packaging, the method comprising: Obtain the ultrasonic inspection image of each packaged sample under the same batch process, determine the suspected defect area and module area in each ultrasonic inspection image through template matching; obtain the ultrasonic signal of each pixel position in each suspected defect area in the ultrasonic inspection image; For each ultrasonic detection image, the distribution suspected index of each suspected defect area is obtained according to the proportion of each suspected defect area and the distance between the suspected defect area and the module area; the pore characteristic index of each pixel point is obtained according to the similarity between each pixel point in each suspected defect area and other pixel points in distribution position and ultrasonic signal fluctuation; the possible pore defect index of each suspected defect area is obtained according to the distribution suspected index of each suspected defect area and the pore characteristic index of the pixel point; For each suspected defect area of ​​each ultrasonic detection image, the overlapping distribution degree between the suspected defect areas of other ultrasonic detection images is analyzed, and combined with the possible indicators of pore defects, the corrected possible indicators of each suspected defect area are obtained; and pore defect detection is performed based on the corrected possible indicators.

[0006] Furthermore, the method for obtaining the distribution suspected indicator includes: For any suspected defect area, the shortest distance between the suspected defect area and the module area is obtained, and after negative correlation mapping and normalization processing, the position distribution index of the suspected defect area is obtained; Normalizing the overlapping area between the suspected defect area and the module area to obtain a distribution ratio index of the suspected defect area; The position distribution index and the distribution ratio index of the suspected defect area are combined to obtain the distribution suspected index of the suspected defect area.

[0007] Furthermore, the method for obtaining the pore characteristic index includes: For any pixel point in a suspected defect area, a time sequence fluctuation sequence of the pixel point is obtained according to the time sequence fluctuation of the ultrasonic signal of the pixel point according to the frequency; Each other pixel in the suspected defect area where the pixel is located is taken as an analysis similarity point in turn; the distance between the pixel and the analysis pixel is negatively correlated and normalized to obtain the distance credibility of the analysis pixel; Negative correlation mapping is performed between the DTW values ​​of the time series fluctuation sequence between the pixel point and the analysis pixel point to obtain the amplitude similarity of the analysis pixel point; The similarity index of the analyzed pixel points is obtained by combining the distance credibility and amplitude similarity of the analyzed pixel points; The average of the similarity indexes of all other pixels of the pixel is used as the pore characteristic index of the pixel.

[0008] Furthermore, the method for obtaining possible indicators of pore defects includes: For any suspected defect area, the ratio of the mean value and the standard deviation of the pore characteristic index of all pixels in the suspected defect area is used as the suspected pore characteristic index of the suspected defect area; The product of the suspected index of the pore characteristics and the suspected index of the distribution of the suspected defect area is used as the possible index of the pore defect of the suspected defect area.

[0009] Furthermore, the method for obtaining the possible correction indicator includes: For any ultrasonic test image, the suspected defect area in the ultrasonic test image is used as the target area in turn; and each other ultrasonic test image outside the ultrasonic test image is used as the analysis image in turn; When the target area overlaps with the suspected defect area in the analysis diagram, the overlapping area ratio of the target area and the suspected defect area in the analysis diagram is used as the defect overlap of the analysis diagram; the product of the possible index of pore defects and the defect overlap of the suspected defect area in the analysis diagram that overlaps with the target area is used as the repeated suspected index of the analysis diagram; When there is no overlap between the target area and the suspected defect area in the analysis diagram, the preset repetition index is used as the repetition suspected index of the analysis diagram; The sum of the repeated suspected indicators of all analysis graphs is used as the correction adjustment degree of the target area; the possible indicators of pore defects in the target area are combined with the correction adjustment degree and normalized to obtain the possible correction indicators of the target area.

[0010] Further, the porosity defect detection based on the correction possible index includes: The maximum possible correction index in each ultrasonic test image is used as the detection index of each ultrasonic test image; when the detection index is greater than the preset defect threshold, the packaging sample corresponding to the ultrasonic test image is recorded as having a pore defect.

[0011] Further, the determining of the suspected defect area and the module area in each ultrasonic detection image by template matching includes: For any ultrasonic detection image, template matching is performed between the ultrasonic detection image and the module area in the preset template image to obtain the module area of ​​the ultrasonic detection image; The ultrasonic detection image is input into the trained neural network model, and the suspected defect area of ​​the ultrasonic detection image is output.

[0012] Furthermore, the method for acquiring the time series fluctuation sequence includes: Performing Fourier transform on the ultrasonic signal of the pixel point to obtain the frequency of the ultrasonic signal of the pixel point; The ultrasonic signal of the pixel point is divided periodically according to the frequency to obtain the amplitude of each period; the amplitudes are arranged in time sequence to obtain the time sequence fluctuation sequence of the pixel point.

[0013] The present invention also provides an ultrasonic detection system for integrated circuit plastic packaging, comprising: The data acquisition module is used to obtain the ultrasonic inspection image of each package sample under the same batch process, determine the suspected defect area and module area in each ultrasonic inspection image through template matching; and obtain the ultrasonic signal of each pixel position in each suspected defect area in the ultrasonic inspection image; The pore defect analysis module is used to obtain the distribution suspected index of each suspected defect area according to the proportion of each suspected defect area and the distance from the module area for each ultrasonic detection image; obtain the pore characteristic index of each pixel point according to the similarity between each pixel point and other pixel points in the distribution position and ultrasonic signal fluctuation in each suspected defect area; obtain the possible pore defect index of each suspected defect area according to the distribution suspected index of each suspected defect area and the pore characteristic index of the pixel point; The correction analysis detection module is used to analyze the overlapping distribution degree of the suspected defect areas between each suspected defect area of ​​each ultrasonic detection image and other suspected defect areas, and obtain the corrected possible indicators of each suspected defect area in combination with the possible indicators of pore defects; and perform pore defect detection based on the corrected possible indicators.

[0014] The present invention also provides an ultrasonic detection device for integrated circuit plastic packaging, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of any one of the above-mentioned ultrasonic detection methods for integrated circuit plastic packaging are implemented.

[0015] The present invention has the following beneficial effects: The present invention takes into account the random characteristics of the location characteristics of pore defects and electromagnetic noise. According to the proportion of suspected defect areas in the ultrasonic detection image of each sample and the distance distribution from the module area, the distribution suspected index is first analyzed from the distribution position, and combined with the similarity of ultrasonic signal fluctuations between pixel points in the area, the pore characteristic index is analyzed from the internal distribution similarity to obtain the possible index of pore defects to reflect the possible degree of pore defects, providing an analytical basis for the screening of pore defects. Further utilizing the high repeatability of packaging defects under the same process, combined with the overlapping performance of suspected defect areas between multiple ultrasonic detection images, the possible index of pore defects is corrected to obtain a more accurate corrected possible index for pore detection. The present invention improves the accuracy of distinguishing electromagnetic noise and pore defects by the similarity of defect characteristics in defect areas between ultrasonic detection images of multiple samples and the degree of overlapping distribution, making defect detection more accurate, thereby improving the reliability of the optimization of subsequent process parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A flow chart of an ultrasonic detection method for integrated circuit plastic packaging provided by one embodiment of the present invention; Figure 2 A schematic diagram of a local ultrasonic detection image of a pore defect provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0018] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the ultrasonic detection method, system and device for integrated circuit plastic packaging proposed by the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments, and its specific implementation, structure, characteristics and effects are described as follows. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0019] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0020] The following is a detailed description of a specific solution of an ultrasonic detection method, system and device for integrated circuit plastic packaging provided by the present invention in conjunction with the accompanying drawings.

[0021] Embodiment 1: See also Figure 1 , which shows a flow chart of an ultrasonic detection method for integrated circuit plastic packaging provided by an embodiment of the present invention, the method comprising the following steps: S1: Obtain the ultrasonic inspection image of each packaged sample under the same batch process, determine the suspected defect area and module area in each ultrasonic inspection image through template matching; obtain the ultrasonic signal of each pixel position in each suspected defect area in the ultrasonic inspection image.

[0022] In the implementation of the present invention, the integrated circuit's plastic encapsulation process includes: selecting a plastic encapsulation material block of appropriate size to be able to wake up the material in a dry environment; after the wake-up is completed, the packaged product is transferred to the preheating table, the preheating temperature is set, and preheating is performed; then, the plastic encapsulation film is adjusted according to the heating device of the upper and lower molds to make the mold temperature in a constant temperature state, and the preheated whole mold frame is moved into the plastic encapsulation mold through the upper and lower material racks to complete the plastic encapsulation process of the integrated circuit.

[0023] At the same time, the packaging process parameters of the packaged circuit are recorded, such as preheating temperature, mold temperature or plastic sealing time, etc. Different process parameters will result in different plastic sealing defects. Therefore, usually a better process parameter selection is determined by defect detection under different packaging process parameters. In the embodiment of the present invention, the packaged circuits under the same process parameters of the same batch are sampled to obtain multiple packaging samples under the process parameters, and then these packaging samples are ultrasonically tested to obtain ultrasonic detection images.

[0024] During the ultrasonic testing of integrated circuit plastic packaging, it is easy to be disturbed by the normal co-operation of electronic components in the testing equipment, resulting in electronic noise in the ultrasonic image. There are a large number of electronic components in the ultrasonic testing equipment, such as amplifiers, digital-to-analog converters, etc. The normal co-operation of these components generates thermal noise. Thermal noise is generated by the irregular movement of electrons, which causes random voltage fluctuations in the output signal, thereby causing random fluctuations in the intensity of ultrasound, resulting in a spot-like image on the ultrasonic image. This shape is very similar to the characteristics of pore defects in the packaging process. Porosity defects also appear as spots in the ultrasonic image of the integrated circuit. Tiny pores cause the ultrasonic echo signal to weaken, appearing as spots in the ultrasonic image, which affects the judgment of the real defect.

[0025] In order to facilitate the subsequent further analysis of the authenticity of the pore defects, preliminary data analysis is performed on the ultrasonic detection image, and the suspected defect areas and module areas in each ultrasonic detection image are determined through preliminary analysis by template matching. In an embodiment of the present invention, for any ultrasonic detection image, the ultrasonic detection image is template matched with the module area in the preset template image to obtain the module area of ​​the ultrasonic detection image. The preset template image is a real integrated circuit template, including a processor module, a memory module, an I / O module or a logic control module of the integrated circuit. The corresponding area position of the module in the ultrasonic detection image is marked as the module area through template matching.

[0026] The ultrasonic detection image is further input into the trained neural network model, and the suspected defect area of ​​the ultrasonic detection image is output. The pore defect is preliminarily detected and judged by the trained neural network model, and the suspected defect area is obtained for subsequent authenticity analysis. It should be noted that template matching and neural network model classification are technical means well known to those skilled in the art, and will not be described in detail here.

[0027] Taking into account that electromagnetic interference exhibits a random pulse phenomenon in the time domain and that ultrasonic signals exhibit unstable electronic interference, analysis of ultrasonic signals is added to subsequent analysis. In an embodiment of the present invention, an ultrasonic probe is used to obtain an ultrasonic signal at each pixel position in each suspected defect area in the ultrasonic detection image, that is, the waveform of the probe from signal transmission to reception.

[0028] S2: For each ultrasonic detection image, the distribution index of each suspected defect area is obtained according to the proportion of each suspected defect area and the distance between the suspected defect area and the module area.

[0029] If the pore defects are generated during the IC packaging process, the defects such as tiny pores or voids are often related to the IC packaging structure. Such defects often appear at the junction of the packaging material and the various modules of the circuit during the packaging process, such as the pin part of the processor chip. Therefore, the pore defects are often located near the various modules of the circuit, please refer to Figure 2 , which shows a schematic diagram of a local ultrasonic detection diagram of a pore defect provided by an embodiment of the present invention.

[0030] Therefore, the closer the defect location is to the module location of the integrated circuit and the higher the area where the position overlaps, the greater the possibility of abnormalities due to packaging factors during the packaging process, and the greater the possibility that the defective area is a real pore defect. Therefore, we first analyze the distribution of suspected defective areas.

[0031] Preferably, in an embodiment of the present invention, the method for obtaining a distribution suspected indicator includes: First, for any suspected defect area, the shortest distance between the suspected defect area and the module area is obtained, and after negative correlation mapping and normalization processing, the position distribution index of the suspected defect area is obtained. The shortest distance between the suspected defect area and the module area is used to reflect the authenticity of the defect from the distribution position characteristics between the modules. In the embodiment of the present invention, the Euclidean distance between the center point of the suspected defect area and each module area is calculated, and the minimum Euclidean distance is used as the shortest distance to determine the position between the areas.

[0032] It should be noted that Euclidean distance, negative correlation mapping and normalization processing are all well-known techniques to those skilled in the art. Negative correlation mapping can adopt inverse proportion or negative exponential power form, etc., and normalization processing can adopt linear normalization or standard normalization, etc., without further limitation or elaboration.

[0033] Furthermore, the overlapping area between the suspected defect area and the module area is normalized to obtain a distribution ratio index of the suspected defect area. The larger the area with the overlapping ratio, the higher the possibility of the defect.

[0034] Finally, the position distribution index and the distribution ratio index of the suspected defect area are combined to obtain the distribution suspected index of the suspected defect area. In an embodiment of the present invention, the product of the position distribution index and the distribution ratio index is used as the distribution suspected index of the suspected defect area. When the position distribution index and the distribution ratio index are larger, it means that the suspected defect area is closer to the module distribution and the degree of overlap is greater, so the possibility that the area is a real pore defect is higher.

[0035] S3: According to the similarity between each pixel point in each suspected defect area and other pixel points in distribution position and ultrasonic signal fluctuation, the pore characteristic index of each pixel point is obtained; according to the distribution suspected index of each suspected defect area and the pore characteristic index of the pixel point, the possible index of the pore defect of each suspected defect area is obtained.

[0036] However, defects that are not located in the module part of the integrated circuit are necessarily real defects. Since electromagnetic noise appears randomly in the ultrasound image, the area that appears in the module of the circuit may still be electromagnetic noise interference.

[0037] Considering that electromagnetic interference exhibits random pulse characteristics in the time domain, the ultrasonic signal changes with a large amplitude for a moment, and then quickly returns to the normal amplitude. This makes the signal unstable due to electronic interference. In a normal ultrasonic signal, the signal usually shows stable changes in time sequence. Therefore, the amplitude of the ultrasonic signal in different positions is different.

[0038] For real packaging pore defects, since the position of the defect is fixed, the ultrasonic signal will cause the same degree of signal change when passing through the pore defect, and the distance between the ultrasonic signal and the defect position is unchanged, so the period in which the signal decays is basically consistent. Therefore, we further analyze the distribution of different pixel points and the fluctuation of the ultrasonic signal to analyze the degree of pore defects at each pixel point.

[0039] Preferably, in an embodiment of the present invention, the method for obtaining the pore characteristic index includes: First, for any pixel point in a suspected defect area, the temporal fluctuation sequence of the pixel point is obtained according to the temporal fluctuation of the ultrasonic signal of the pixel point according to the frequency. In an embodiment of the present invention, the ultrasonic signal of the pixel point is Fourier transformed to obtain the frequency of the ultrasonic signal of the pixel point, and the intensity of different frequency components in the signal is analyzed by Fourier transform. The ultrasonic signal of the pixel point is periodically divided according to the frequency to obtain the amplitude of each period, and the amplitudes are arranged in a temporal order to obtain the temporal fluctuation sequence of the pixel point. It should be noted that Fourier transform and period amplitude acquisition are both well-known technical means well known to those skilled in the art, and will not be elaborated here.

[0040] The amplitude change of the ultrasonic signal reflects the internal structural change of the integrated circuit at the monitoring position. If it is a defect caused by normal packaging, all the pixels in the defect area jointly reflect the internal pore defect of the integrated circuit package. Since the pixels jointly reflect the internal defect characteristics, they have a high similarity, that is, the same amplitude appears in similar cycles. Therefore, the ultrasonic signals at similar positions monitor the same defect position of the package pore, and the ultrasonic signals are similar.

[0041] Furthermore, each other pixel in the suspected defect area where the pixel is located is taken as an analysis similarity point in turn, and all other pixel points in the area are analyzed. The distance between the pixel and the analysis pixel is negatively correlated and normalized to obtain the distance credibility of the analysis pixel. If the distribution distance is small, it is more likely to correspond to the same pore defect situation, and the focus is more on the similarity analysis. When the distribution distance is large, the pore defects may not be in the same position, and low similarity may be a normal phenomenon, so it is adjusted by the distance between the distributions.

[0042] Furthermore, the DTW value between the pixel point and the time series fluctuation sequence between the analyzed pixel points is negatively correlated to obtain the amplitude similarity of the analyzed pixel point, and the similarity between the sequences is reflected by the DTW value. The smaller the DTW value, the more similar the two sequences are. It should be noted that the DTW value is obtained by the DTW algorithm, which is a well-known technical means well known to those skilled in the art and is not limited here.

[0043] Furthermore, the distance credibility and amplitude similarity of the analysis pixel point are combined to obtain a similarity index of the analysis pixel point. In an embodiment of the present invention, the product of the distance credibility and amplitude similarity of the analysis pixel point is used as the similarity index of the analysis pixel point. The larger the distance credibility and the amplitude similarity, the closer the distance between the analysis pixel point and the pixel point and the more similar the ultrasonic signal performance is, so the larger the similarity index is.

[0044] Finally, the average of the similarity indexes of all other pixels of the pixel is used as the stomatal characteristic index of the pixel. The stomatal characteristic significance of the pixel is obtained by combining the similarity analysis of all other pixels.

[0045] The possible degree of micro-pore defects is comprehensively reflected by combining the distribution position and the pore characteristics of similar points for each suspected defect area. Therefore, in the embodiment of the present invention, the possible pore defect indicators of each suspected defect area are obtained according to the distribution suspected indicators of each suspected defect area and the pore characteristic indicators of the pixel points, including: For any suspected defect area, the ratio of the mean value and the standard deviation of the pore characteristic index of all pixels in the suspected defect area is used as the suspected pore characteristic index of the suspected defect area. The greater the degree of representation of the overall pore characteristics of the pixels in the suspected defect area and the smaller the degree of fluctuation, the higher the authenticity of the pore defect in the area.

[0046] Finally, the product of the suspected pore characteristic index and the suspected distribution index of the suspected defect area is used as the possible index of the pore defect in the suspected defect area. The larger the suspected pore characteristic index and the suspected distribution index are, the higher the possibility that the suspected defect area is a real pore defect is.

[0047] S4: For each suspected defect area of ​​each ultrasonic detection image, analyze the overlapping distribution degree of the suspected defect areas between other ultrasonic detection images, and obtain the corrected possible indicators of each suspected defect area in combination with the possible indicators of pore defects; perform pore defect detection based on the corrected possible indicators.

[0048] Considering that the ultrasound at the module boundary will also be affected by the contours of each module of the integrated circuit, the amplitude difference is reflected as a normal change of the integrated circuit. At this time, it is interfered by electromagnetic noise, resulting in the noise at this time still having a high similarity with the real packaging pore defect. The package pore defect of the integrated circuit is caused by the inaccurate packaging process parameters. Under the same process parameters, the integrated circuit has a high probability of reproducing the package pore defect. If it is manifested as electromagnetic noise, the position and size of the ultrasonic image detected each time have a high randomness. Therefore, in multiple ultrasonic detection processes and, if the location and other characteristics of the defect have a high repeatability, the possibility of a real packaging defect is greater.

[0049] Therefore, by analyzing the overlap of defect areas with other ultrasonic detection images, the possible indicators of each defect area are further adjusted to improve the accuracy of detection. Preferably, in an embodiment of the present invention, the method for obtaining the correct possible indicators includes: For any ultrasonic detection image, the suspected defect area in the ultrasonic detection image is taken as the target area in turn, and each suspected defect area is analyzed. Each other ultrasonic detection image other than the ultrasonic detection image is taken as the analysis image in turn, and each other ultrasonic detection image is analyzed in turn.

[0050] When the target area overlaps with the suspected defect area in the analysis diagram, it means that the defect may be reproducible in this analysis diagram, and the area ratio of the target area overlapping with the suspected defect area in the analysis diagram in the position-related suspected defect area is taken as the defect overlap of the analysis diagram. In the embodiment of the present invention, the area ratio is the ratio of the area between the overlapping part and the target area. The higher the degree of overlap, the higher the similarity in size or shape of the defect area, and the higher the credibility of the area as a real pore defect.

[0051] The product of the possible index of the pore defect in the suspected defect area overlapping with the target area in the analysis diagram and the defect overlap degree is further taken as the repeated suspected index of the analysis diagram. The larger the repeated suspected index is, the more likely the reproduction of the analysis diagram is to be a real pore defect, reflecting the degree of correction of the reproduction of the target area by the analysis diagram.

[0052] When there is no overlap between the target area and the suspected defect area in the analysis diagram, it means that there is no recurrence at this time, and the preset repetition index is used as the suspected repetition index of the analysis diagram. In an embodiment of the present invention, the preset repetition index is set to 0, and the specific value can be adjusted by the implementer and is not limited here.

[0053] The sum of the repeated suspected indicators of all analysis graphs is used as the correction adjustment degree of the target area, reflecting the degree to which the overall target area is affected by the degree of repetition. Finally, the possible index of the pore defect of the target area and the correction adjustment degree are combined and normalized to obtain the possible correction index of the target area. In the embodiment of the present invention, the sum of the possible index of the pore defect of the target area and the correction adjustment degree is normalized to obtain the possible correction index of the target area. The larger the possible correction index is, the higher the possibility that the target area is a pore defect.

[0054] The existence of defects in the integrated circuit can be determined by analyzing the possible correction indicators of the suspected defective areas in the ultrasonic detection image. In an embodiment of the present invention, the maximum possible correction indicator in each ultrasonic detection image is used as the detection indicator of each ultrasonic detection image, and the defect characterization possibility in the ultrasonic detection image is represented by the maximum value.

[0055] When the detection index is greater than the preset defect threshold, it indicates that the pore defect is significant, and the package sample corresponding to the ultrasonic detection image is recorded as having pore defects. In the embodiment of the present invention, the preset defect threshold is set to 0.9, and the specific value can be adjusted by the implementer according to the specific implementation scenario, and is not limited here.

[0056] At this point, the analysis of the sample pore defects is completed. Subsequently, a mapping analysis of defects and process parameters can be performed based on the defect conditions under different process parameters to determine the optimal process parameters to improve the quality of plastic packaging.

[0057] It is worth mentioning that all data involved in the calculation in this embodiment have been dimensionally eliminated to avoid the influence of different dimensions on parameter analysis. Dimensionality elimination is a well-known technical means well known to those skilled in the art and will not be elaborated or limited here.

[0058] In summary, the present invention takes into account the random characteristics of the location characteristics of pore defects and electromagnetic noise, and first analyzes the distribution suspected index from the distribution position according to the proportion of suspected defect areas in the ultrasonic detection image of each sample and the distance distribution from the module area, and combines the similarity of ultrasonic signal fluctuations between pixel points in the area to analyze the pore characteristic index from the similarity of the internal distribution to reflect the possible degree of pore defects and provide an analytical basis for the screening of pore defects. Further utilizing the high repeatability of packaging defects under the same process, combined with the overlapping performance of suspected defect areas between multiple ultrasonic detection images, the possible pore indicators are corrected to obtain more accurate corrected possible indicators for pore detection. The present invention improves the accuracy of distinguishing electromagnetic noise and pore defects by the degree of similar characterization of defect characteristics in defect areas between ultrasonic detection images of multiple samples and the degree of overlapping distribution, making defect detection more accurate, thereby improving the reliability of the optimization of subsequent process parameters.

[0059] Embodiment 2: The present invention also provides an ultrasonic detection system for integrated circuit plastic packaging, comprising: The data acquisition module is used to obtain the ultrasonic inspection image of each package sample under the same batch process, determine the suspected defect area and module area in each ultrasonic inspection image through template matching; and obtain the ultrasonic signal of each pixel position in each suspected defect area in the ultrasonic inspection image; The pore defect analysis module is used to obtain the distribution suspected index of each suspected defect area according to the proportion of each suspected defect area and the distance from the module area for each ultrasonic detection image; obtain the pore characteristic index of each pixel point according to the similarity between each pixel point and other pixel points in the distribution position and ultrasonic signal fluctuation in each suspected defect area; obtain the possible pore defect index of each suspected defect area according to the distribution suspected index of each suspected defect area and the pore characteristic index of the pixel point; The correction analysis detection module is used to analyze the overlapping distribution degree of the suspected defect areas between each suspected defect area of ​​each ultrasonic detection image and other suspected defect areas, and obtain the corrected possible indicators of each suspected defect area in combination with the possible indicators of pore defects; and perform pore defect detection based on the corrected possible indicators.

[0060] It should be noted that the system provided in the above embodiment is only illustrated by the division of the above functional modules. In actual applications, the above functions can be assigned to different functional module units as needed, that is, the internal structure of the system is divided into different functional module units to complete all or part of the functions described above. Since the specific implementation process of an ultrasonic detection system for integrated circuit plastic packaging in this embodiment is the same as the specific implementation process of an ultrasonic detection method for integrated circuit plastic packaging in the above embodiment, it will not be repeated here.

[0061] Embodiment 3: The present invention also provides an ultrasonic detection device for integrated circuit plastic packaging, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of any one of the above-mentioned ultrasonic detection methods for integrated circuit plastic packaging are implemented.

[0062] It should be noted that the sequence of the above embodiments of the present invention is only for description and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0063] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

Claims

1. An ultrasonic detection method for integrated circuit plastic packaging, characterized in that: The method comprises: Obtain the ultrasonic inspection image of each package sample under the same batch process, determine the suspected defect area and module area in each ultrasonic inspection image through template matching; obtain the ultrasonic signal of each pixel position in each suspected defect area in the ultrasonic inspection image; For each ultrasonic detection image, the distribution suspected index of each suspected defect area is obtained according to the proportion of each suspected defect area and the distance between it and the module area; the pore characteristic index of each pixel point is obtained according to the similarity between each pixel point in each suspected defect area and other pixel points in distribution position and ultrasonic signal fluctuation; the possible pore defect index of each suspected defect area is obtained according to the distribution suspected index of each suspected defect area and the pore characteristic index of the pixel point; For each suspected defect area of ​​each ultrasonic detection image, the overlapping distribution degree between the suspected defect areas of other ultrasonic detection images is analyzed, and combined with the possible indicators of pore defects, the corrected possible indicators of each suspected defect area are obtained; and pore defect detection is performed based on the corrected possible indicators.

2. The ultrasonic detection method for integrated circuit plastic packaging according to claim 1, characterized in that: The method for obtaining the distribution suspected indicator includes: For any suspected defect area, the shortest distance between the suspected defect area and the module area is obtained, and after negative correlation mapping and normalization processing, the position distribution index of the suspected defect area is obtained; Normalizing the overlapping area between the suspected defect area and the module area to obtain a distribution ratio index of the suspected defect area; The position distribution index and the distribution ratio index of the suspected defect area are combined to obtain the distribution suspected index of the suspected defect area.

3. The ultrasonic detection method for integrated circuit plastic packaging according to claim 1, characterized in that: The method for obtaining the pore characteristic index comprises: For any pixel point in a suspected defect area, a time sequence fluctuation sequence of the pixel point is obtained according to the time sequence fluctuation of the ultrasonic signal of the pixel point according to the frequency; Each other pixel in the suspected defect area where the pixel is located is taken as an analysis similarity point in turn; the distance between the pixel and the analysis pixel is negatively correlated and normalized to obtain the distance credibility of the analysis pixel; Negative correlation mapping is performed between the DTW values ​​of the time series fluctuation sequence between the pixel point and the analysis pixel point to obtain the amplitude similarity of the analysis pixel point; The similarity index of the analyzed pixel points is obtained by combining the distance credibility and amplitude similarity of the analyzed pixel points; The average of the similarity indexes of all other pixels of the pixel is used as the pore characteristic index of the pixel.

4. The ultrasonic detection method for integrated circuit plastic packaging according to claim 1, characterized in that: The method for obtaining the possible indicators of the pore defects includes: For any suspected defect area, the ratio of the mean value and the standard deviation of the pore characteristic index of all pixels in the suspected defect area is used as the suspected pore characteristic index of the suspected defect area; The product of the suspected index of the pore characteristics and the suspected index of the distribution of the suspected defect area is used as the possible index of the pore defect of the suspected defect area.

5. The ultrasonic detection method for integrated circuit plastic packaging according to claim 1, characterized in that: The method for obtaining the correction possible indicator includes: For any ultrasonic test image, the suspected defect area in the ultrasonic test image is used as the target area in turn; and each other ultrasonic test image outside the ultrasonic test image is used as the analysis image in turn; When the target area overlaps with the suspected defect area in the analysis diagram, the overlapping area ratio of the target area and the suspected defect area in the analysis diagram is used as the defect overlap of the analysis diagram; the product of the possible index of pore defects and the defect overlap of the suspected defect area in the analysis diagram that overlaps with the target area is used as the repeated suspected index of the analysis diagram; When there is no overlap between the target area and the suspected defect area in the analysis diagram, the preset repetition index is used as the repetition suspected index of the analysis diagram; The sum of the repeated suspected indicators of all analysis graphs is used as the correction adjustment degree of the target area; the possible indicators of pore defects in the target area are combined with the correction adjustment degree and normalized to obtain the possible correction indicators of the target area.

6. The ultrasonic detection method for integrated circuit plastic packaging according to claim 1, characterized in that: The method of performing pore defect detection based on the correction of possible indicators includes: The maximum possible correction index in each ultrasonic test image is used as the detection index of each ultrasonic test image; when the detection index is greater than the preset defect threshold, the packaging sample corresponding to the ultrasonic test image is recorded as having a pore defect.

7. The ultrasonic detection method for integrated circuit plastic packaging according to claim 1, characterized in that: The method of determining the suspected defect area and the module area in each ultrasonic detection image by template matching includes: For any ultrasonic detection image, template matching is performed between the ultrasonic detection image and the module area in the preset template image to obtain the module area of ​​the ultrasonic detection image; The ultrasonic detection image is input into the trained neural network model, and the suspected defect area of ​​the ultrasonic detection image is output.

8. The ultrasonic detection method for integrated circuit plastic packaging according to claim 3, characterized in that: The method for acquiring the time series fluctuation sequence includes: Performing Fourier transform on the ultrasonic signal of the pixel point to obtain the frequency of the ultrasonic signal of the pixel point; The ultrasonic signal of the pixel point is divided periodically according to the frequency to obtain the amplitude of each period; the amplitudes are arranged in time sequence to obtain the time sequence fluctuation sequence of the pixel point.

9. An ultrasonic detection system for integrated circuit plastic packaging, characterized in that: include: The data acquisition module is used to obtain the ultrasonic inspection image of each package sample under the same batch process, determine the suspected defect area and module area in each ultrasonic inspection image through template matching; and obtain the ultrasonic signal of each pixel position in each suspected defect area in the ultrasonic inspection image; The pore defect analysis module is used to obtain the distribution suspected index of each suspected defect area according to the proportion of each suspected defect area and the distance from the module area for each ultrasonic detection image; obtain the pore characteristic index of each pixel point according to the similarity between each pixel point and other pixel points in the distribution position and ultrasonic signal fluctuation in each suspected defect area; obtain the possible pore defect index of each suspected defect area according to the distribution suspected index of each suspected defect area and the pore characteristic index of the pixel point; The correction analysis detection module is used to analyze the overlapping distribution degree of the suspected defect areas between each suspected defect area of ​​each ultrasonic detection image and other suspected defect areas, and obtain the corrected possible indicators of each suspected defect area in combination with the possible indicators of pore defects; and perform pore defect detection based on the corrected possible indicators.

10. An ultrasonic detection device for integrated circuit plastic packaging, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the ultrasonic detection method for integrated circuit plastic packaging as described in any one of claims 1 to 8 are implemented.

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