A flip-chip FC packaging technology method

Abstract

The present invention discloses a flip-chip FC packaging technology method, which relates to the field of chip packaging technology. The physical parameters of the materials for flip-chip packaging are collected, and a thermal-mechanical coupling model is established. Using the established thermal-mechanical coupling model, thermo-mechanical coupling simulation and mechanical stress analysis are carried out on the packaging structure to identify the stress concentration areas and the parts with large deformations. Based on the results of the thermal-mechanical coupling analysis, an optimized design of the packaging structure is carried out. Through optimized design and strict testing procedures, the present invention significantly improves the reliability of the packaging structure. In the design stage, thermal-mechanical coupling analysis is used to identify the stress concentration areas and potential deformation problems, so as to optimize the geometry, material selection and solder ball layout in advance. Moreover, by optimizing the thermal management strategy, the thermal management performance of the packaging structure is effectively improved, and the heat dissipation efficiency of the packaging structure is significantly increased, enabling the packaging structure to better adapt to application scenarios with extremely high requirements for thermal management.

Description

Technical Field

[0001] The present invention relates to the technical field of chip packaging, and specifically relates to a flip chip FC packaging technology method. Background Art

[0002] The flip chip (abbreviated as FC) packaging technology is an advanced integrated circuit packaging technology, mainly stemming from the semiconductor industry's continuous pursuit of improving chip performance, size, cost, and production efficiency. It involves inverting the chip and directly connecting the chip's pads to the packaging substrate, eliminating the step of wire bonding in traditional packaging methods. This technology enables more compact electrical connections and superior chip performance, thus being widely used in modern electronic products.

[0003] In the prior art, stress changes in flip chip packaging can lead to poor contact between the chip and the substrate. Especially under temperature changes or physical vibrations, problems such as temperature cycling, differences in thermal expansion coefficients, and mechanical shock are likely to cause stress concentration in the packaging, resulting in failures. Therefore, how to combine mechanical models with thermal models to analyze the thermo-mechanical coupling effects in the design stage and then optimize the packaging structure to minimize stress and deformation is the problem to be solved. For this reason, a flip chip FC packaging technology method is proposed herein. Summary of the Invention

[0004] The purpose of the present invention is to provide a flip chip FC packaging technology method to solve the problems raised in the above background art.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0006] A flip chip FC packaging technology method includes the following steps:

[0007] Step 1: Collect the material physical parameters of flip chip packaging, including the thermal expansion coefficients, elastic moduli, thermal conductivities, etc. of the chip material, substrate material, and solder ball material, and establish a thermo-mechanical coupling model. Among them, the thermo-mechanical coupling model includes the mechanical and thermal models of the complete packaging structure including the chip, bumps, and substrate, and is used to simulate the behavior of the packaging structure under thermo-mechanical loads.

[0008] Step 2: Use the established thermo-mechanical coupling model to perform thermo-mechanical coupling simulation and mechanical stress analysis on the packaging structure, simulate and analyze the stress and deformation states of the packaging structure under temperature cycling, physical vibration, and mechanical shock conditions, identify the stress concentration areas and the parts with large deformations, and evaluate the impact on the packaging reliability.

[0009] Step 3: Based on the thermo-mechanical coupling analysis results, conduct an optimized design of the packaging structure, including adjusting the geometric shapes of the chip and the substrate, material selection, thermal management optimization, and contact stability optimization, to reduce stress concentration and deformation. The goal is to improve the thermal management effect and optimize the stress distribution to make the contact between the chip and the substrate more stable;

[0010] Step 4: After the optimized design, conduct a thermo-mechanical coupling effect analysis on the optimized packaging structure again to verify whether the optimization effect meets the design requirements. If the optimization effect is not ideal, return to Step 3 to continue adjusting the design parameters until the requirements are met;

[0011] Step 5: Combine the optimized design parameters that meet the design requirements to conduct prototype manufacturing and testing to verify the accuracy of the simulation results. Among them, the testing process includes temperature cycle testing, mechanical shock testing, and reliability testing, etc., to verify its performance in actual applications;

[0012] Step 6: If the prototype manufacturing and testing are passed, apply the optimized design parameters to implement mass production and apply the flip-chip FC packaging technology to actual products. Otherwise, return to Step 2 to continue the thermo-mechanical coupling effect analysis until the flip-chip packaging requirements are met.

[0013] A further improvement of the technical solution of the present invention lies in that: Step 1 specifically includes:

[0014] Traverse the technical specifications, data manuals, and industry standards in the field of electronic packaging to obtain the material physical parameters of flip-chip packaging, including the thermal expansion coefficients, elastic moduli, and thermal conductivities of the chip material, substrate material, and solder ball material, etc.;

[0015] Use 3D modeling software to construct a geometric model of the flip-chip packaging. The geometric model is a complete packaging structure including the chip, bumps, and substrate, ensuring that the geometric dimensions of the model are consistent with the actual packaging design, including the chip size, bump position and size, substrate thickness, etc., and import the collected material physical parameters and geometric model into finite element analysis software (ANSYS, ABAQUS, etc.), conduct mesh division on the model, select a suitable mesh type (tetrahedral mesh, hexahedral mesh) and mesh density, and create a finite element model;

[0016] In the finite element model, combine the collected material physical parameters to assign corresponding material properties to the chip, bumps, and substrate respectively to ensure the accuracy of the simulation results;

[0017] Define the thermal boundary conditions of the package structure, including the heat source (chip heating), heat dissipation paths (substrate, heat sink cover), and ambient temperature, and use the heat conduction equation to simulate the thermal distribution of the package structure under different temperature conditions, calculate the temperature field distribution, and then define the mechanical boundary conditions of the package structure, including fixed constraints (bottom of the substrate) and loads (thermal stress caused by temperature changes), and use the equations of elasticity to simulate the deformation and stress distribution of the package structure under thermal stress;

[0018] In the finite element analysis software, couple the thermal model and the mechanical model to obtain a thermal-mechanical coupling model, and then perform thermal-mechanical coupling analysis to simulate the behavior of the package structure under thermal-mechanical loads, including temperature changes, thermal expansion, stress distribution, and deformation.

[0019] A further improvement of the technical solution of the present invention lies in that: the specific steps of step two include:

[0020] Combined with the requirements of flip-chip packaging, define the working conditions for thermal-mechanical coupling simulation and mechanical stress analysis, including temperature cycle conditions, physical vibration conditions, and mechanical shock conditions, and in the finite element analysis software, set the simulation parameters according to the defined working conditions to ensure that the boundary conditions, load conditions, and material properties of the model are consistent with the actual working conditions, where the simulation parameters include temperature range, cycle period, vibration frequency, acceleration, shock acceleration, and shock duration;

[0021] Combined with the established thermal-mechanical coupling model, perform thermal-mechanical coupling simulation on the package structure, set the temperature cycle curve in the simulation according to the temperature cycle conditions in actual applications, and then use the finite element method to solve the heat conduction equation to calculate the temperature distribution of the package structure under different working conditions, so as to output the temperature field distribution results, including the temperature changes of the chip, bumps, and substrate;

[0022] Combined with the established thermal-mechanical coupling model, perform mechanical stress analysis on the package structure, apply fixed constraints at the bottom of the substrate to simulate the actual installation state of the package structure, input the thermal-mechanical coupling simulation results (thermal stress caused by temperature changes) as loads into the mechanical model, and apply corresponding dynamic loads (acceleration, impact force) to the physical vibration and mechanical shock conditions, and then use the finite element method to solve the equations of elasticity to calculate the stress and deformation of the package structure under thermal stress, vibration, and shock loads, so as to output the stress distribution diagram and deformation diagram;

[0023] Through the simulation results, identify the stress concentration areas, analyze the stress levels in the stress concentration areas, and judge whether they exceed the yield strength or fatigue limit of the material, where the stress concentration areas include the connection between the chip and the substrate and the solder ball positions;

[0024] Analyze the deformation distribution of the packaging structure, identify the parts with large deformations, and evaluate the impact of the deformations on the electrical connections and mechanical stability of the packaging structure. Among them, the deformations include chip warping and substrate bending;

[0025] According to the stress concentration areas and the parts with large deformations, evaluate the failure risks of the packaging structure under temperature cycling, physical vibration, and mechanical shock conditions. Among them, the failure modes of the failure risks include solder ball fracture or fatigue failure, poor contact between the chip and the substrate, substrate cracking or delamination, and electrical short circuit or open circuit caused by chip warping. Then, use the S-N curve to evaluate the fatigue life of the solder balls and the packaging structure, and combine the stress level and deformation conditions to predict the reliable working time of the packaging structure.

[0026] A further improvement of the technical solution of the present invention is that the definition of the temperature cycling condition is: the temperature change range is from -40°C to +125°C, and the cycle period is one cycle per hour, which is used to simulate the thermal expansion and contraction behavior of the packaging structure during temperature cycling;

[0027] The definition of the physical vibration condition is: the vibration frequency is from 10 Hz to 500 Hz, and the acceleration is 10g, which is used to simulate the dynamic response of the packaging structure under periodic vibration;

[0028] The definition of the mechanical shock condition is: the shock acceleration is 100g, and the shock duration is 11 ms, which is used to simulate the stress and deformation of the packaging structure under transient shock.

[0029] A further improvement of the technical solution of the present invention is that the process of identifying the stress concentration areas is as follows:

[0030] Use the post-processing function of the finite element analysis software to output the stress distribution diagrams of the packaging structure under different conditions, and observe the stress distribution diagrams to identify the parts where the stress values are significantly higher than those in the surrounding areas;

[0031] After identifying the stress concentration areas, locally magnify the identified stress concentration areas to observe the stress distribution in more detail, analyze the stress gradient in the stress concentration areas, that is, the change rate of the stress value in space. The high stress gradient area indicates local deformation or damage of the material, and extract the stress data of the stress concentration areas, including the maximum stress value, the average stress value, and the cyclic stress amplitude;

[0032] Compare the extracted maximum stress value with the yield strength of the material. If the maximum stress value exceeds the yield strength of the material, it indicates that there is a risk of plastic deformation or fracture in this area. For the temperature cycling and physical vibration cycling conditions, analyze the cyclic stress amplitude in the stress concentration area, and compare the cyclic stress amplitude with the fatigue limit of the material. If the cyclic stress amplitude exceeds the fatigue limit of the material, it indicates that there is a risk of fatigue failure in this area;

[0033] The process of identifying the part with large deformation is as follows:

[0034] Use the post-processing function of the finite element analysis software to output the deformation distribution diagram of the packaging structure under different working conditions (temperature cycle, physical vibration, mechanical shock), observe the deformation distribution diagram, and identify the parts with large deformation. The deformation distribution diagram uses different colors or heights to represent the size of the deformation. The darker the color or the higher the height, the greater the deformation.

[0035] Analyze the deformation distribution of the chip area, pay attention to the displacement difference between the center and edge of the chip. Chip warping is manifested as the upward or downward bending of the chip center, resulting in an uneven chip surface. The maximum warping of the chip is extracted, and the maximum warping is expressed as the displacement value of the chip center. At the same time, observe the deformation distribution of the substrate area, pay attention to the overall bending degree of the substrate. The substrate bending is manifested as the upward or downward bending of the substrate center, or the warping of the substrate edge. The maximum bending of the substrate is extracted, and the maximum bending is expressed as the displacement value of the substrate center or edge.

[0036] Analyze the impact of chip warpage on electrical connections, including solder ball connection reliability and electrical short or open circuit risks, and analyze the impact of substrate bending on electrical connections, including substrate-chip contact issues and solder ball reliability;

[0037] Analyze the impact of chip warping on mechanical stability, including the mechanical stability of the packaging structure and the fatigue life of the material; analyze the impact of substrate bending on mechanical stability, including the overall stability of the packaging structure and the fatigue life of the material.

[0038] A further improvement of the technical solution of the present invention is that the process of predicting the failure risk and the reliable working time of the packaging structure is:

[0039] Assessment of failure risks, including solder ball fracture or fatigue failure, poor contact between chip and substrate, substrate cracking or delamination, and electrical shorts or breaks caused by chip warping;

[0040] Use the SN curve to evaluate the fatigue life of solder balls and packaging structures under cyclic stress, and combine the stress level and cycle number to predict the fatigue failure time of solder balls and packaging structures;

[0041] The reliability of the packaging structure is evaluated by combining the stress level and deformation in the stress concentration area, focusing on the stress and deformation at the solder ball position and the contact between the chip and the substrate. The reliable working time of the packaging structure is predicted based on the fatigue life assessment results.

[0042] A further improvement of the technical solution of the present invention is that the step three specifically includes:

[0043] Based on the stress concentration regions identified from the thermo-mechanical coupling analysis results and the deformation analysis results, determine the optimization objectives for the package structure design, including improving thermal management effectiveness, optimizing stress distribution, and ensuring firm contact between the chip and the substrate. Improving thermal management effectiveness ensures stable operation of the package structure in high-temperature environments. Optimizing stress distribution reduces stress concentration and deformation, extending the service life of the package structure. Ensuring firm contact between the chip and the substrate improves the reliability and electrical performance of the package.

[0044] For the determined optimization objectives, match the corresponding optimization design measures, including adjusting the geometries of the chip and the substrate, material selection, thermal management optimization, and contact stability optimization.

[0045] Using the optimized design parameters, re-perform finite element analysis to update the finite element simulation model.

[0046] A further improvement in the technical solution of the present invention lies in: Step Four specifically includes:

[0047] Combined with the updated finite element simulation model, re-conduct the thermo-mechanical coupling effect analysis on the optimized package structure, and perform simulation analyses of thermal-mechanical coupling analysis and mechanical stress analysis.

[0048] According to the simulation analysis results, clarify the stress distribution, temperature distribution, and deformation conditions of the optimized package structure under thermal and mechanical loads.

[0049] Extract the results of the finite element analysis, including stress diagrams, temperature diagrams, and deformation diagrams. Compare the results before and after optimization, evaluate the impact of the optimization measures on thermal management effectiveness, stress distribution, and contact stability, and judge whether the optimization effect meets the requirements according to the design requirements of the maximum stress limit, maximum temperature limit, and maximum deformation limit.

[0050] If the optimization effect is ideal, that is, the stress concentration is reduced, the temperature distribution is more uniform, the deformation amount is decreased, and the contact stability is improved, then judge that the optimization effect meets the design requirements and proceed to the next step.

[0051] If the optimization effect is not ideal, that is, the stress is still concentrated, the temperature distribution is uneven, the deformation amount is too large, or the contact stability is insufficient, then return to Step Three to continue adjusting the design parameters, implement design parameter adjustment measures including geometric shape adjustment, material selection optimization, thermal management improvement, and contact stability improvement, and use the updated design parameters to re-conduct finite element analysis to verify the optimization effect until the optimized package structure meets the design requirements.

[0052] A further improvement in the technical solution of the present invention lies in: Step Five specifically includes:

[0053] Based on the results of finite element simulation analysis, determine the optimized design parameters that meet the design requirements, including geometric shape, material selection, thermal management strategy, contact stability optimization measures, etc., and according to the optimized design parameters, formulate a detailed prototype manufacturing plan, including manufacturing process, processing equipment, material procurement, quality control, etc.;

[0054] Combined with the formulated prototype manufacturing plan, formulate a test plan including temperature cycle test, mechanical shock test and reliability test, and clarify the test purpose, test conditions, test equipment and test standards;

[0055] Sort out the result data of the temperature cycle test, mechanical shock test and reliability test, analyze the test results, compare the consistency between the performance of the prototype in the actual test and the simulation results, and evaluate the performance of the prototype in the actual application, including thermal management performance, mechanical strength, shock resistance and long-term reliability;

[0056] According to the test results, judge the accuracy of the simulation results. If the test results are consistent with the simulation results, it indicates that the simulation model is accurate and reliable and can be used to guide subsequent design and optimization. If there are differences between the test results and the simulation results, analyze the reasons for the differences. The reasons for the differences include the simplification of the simulation model, the differences in test conditions or errors in the manufacturing process, etc., and then modify and improve the simulation model.

[0057] A further improvement of the technical solution of the present invention is that: the specific content of step six includes:

[0058] Analyze the test results of prototype manufacturing. If the temperature cycle test, mechanical shock test and reliability test meet the required standards, it is considered that the test is passed and meets the design requirements, and then enter the mass production stage;

[0059] If the prototype manufacturing and test results do not meet the required standards, it is considered that the test fails and it is necessary to return to the optimization design step and continue the optimization process of thermal-mechanical coupling effect analysis, design optimization, and remanufacturing and testing the prototype. If the new prototype still does not meet the design requirements, continue to return to step two for thermal-mechanical coupling effect analysis until the flip chip packaging requirements are met. Through continuous cyclic iteration, gradually optimize the design of the packaging structure to ensure its stability and reliability in actual applications.

[0060] Due to the adoption of the above technical solution, the technical progress achieved by the present invention compared with the prior art is:

[0061] 1. The present invention provides a flip-chip FC packaging technology method. By optimizing the design and following a strict testing process, the reliability of the packaging structure is significantly improved. During the design stage, thermo-mechanical coupling analysis is used to identify stress concentration areas and potential deformation problems, thereby optimizing the geometry, material selection, and solder ball layout in advance. Moreover, by optimizing the thermal management strategy, the thermal management performance of the packaging structure is effectively enhanced, and the heat dissipation efficiency of the packaging structure is significantly improved, enabling the packaging structure to better adapt to application scenarios with extremely high thermal management requirements.

[0062] 2. The present invention provides a flip-chip FC packaging technology method. By adjusting the geometry, optimizing the material selection, and improving the solder ball layout, the stress distribution of the packaging structure is effectively optimized. During the design stage, finite element analysis is used to identify stress concentration areas, such as the solder ball positions and the connection between the chip and the substrate. By adjusting the solder ball pitch, optimizing the chip edge design, and selecting materials with a more matched coefficient of thermal expansion, the stress concentration phenomenon is significantly reduced. As a result, the optimized packaging structure exhibits good structural integrity in the mechanical shock test, without cracks or damage, and the electrical performance remains normal after the shock. This optimized stress distribution not only improves the mechanical strength of the packaging structure but also extends its service life under dynamic load conditions, reducing the risk of fatigue failure caused by stress concentration and ensuring the stability and reliability of the packaging structure in practical applications.

[0063] 3. The present invention provides a flip-chip FC packaging technology method. Through various optimization measures, the contact stability between the chip and the substrate is ensured, which not only improves the electrical performance of the packaging structure but also reduces signal transmission errors and power consumption increases caused by contact problems, enabling the packaging structure to better meet the strict electrical performance requirements of high-performance electronic products. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] 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 required for use in the embodiments. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings.

[0065] Figure 1 It is a schematic diagram of the working process of the present invention;

[0066] Figure 2 It is a schematic diagram of the method process of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0067] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0068] Embodiment 1, as Figure 1 , Figure 2 shown, the present invention provides a flip-chip FC packaging technology method, including the following steps:

[0069] Step 1: Collect the material physical parameters of flip-chip packaging, including the coefficients of thermal expansion, elastic moduli, thermal conductivities, etc. of the chip material, substrate material, and solder ball material, and establish a thermal-mechanical coupling model. The thermal-mechanical coupling model includes the mechanical and thermal models of the complete packaging structure including the chip, bumps, and substrate, and is used to simulate the behavior of the packaging structure under thermal-mechanical loads. Search through the technical specifications, data manuals, and industry standards in the field of electronic packaging to obtain the material physical parameters of flip-chip packaging, including the coefficients of thermal expansion, elastic moduli, and thermal conductivities of the chip material, substrate material, and solder ball material. Among them, consult the technical specifications and data manuals of chip manufacturers, substrate suppliers, and solder ball manufacturers, and record the physical parameters such as the coefficients of thermal expansion, elastic moduli, and thermal conductivities of the chip material, substrate material, and solder ball material. Refer to industry standards in the field of electronic packaging, such as JEDEC (Joint Electron Device Engineering Council), to obtain information on material physical parameters. The industry standards include recommended values or ranges of material properties, which help to verify and supplement the data obtained from manufacturers. Use 3D modeling software to construct the geometric model of flip-chip packaging. The geometric model is the complete packaging structure including the chip, bumps, and substrate, and ensure that the geometric dimensions of the model are consistent with the actual packaging design, including chip size, bump position and size, substrate thickness, etc. Then import the collected material physical parameters (coefficients of thermal expansion, elastic moduli, thermal conductivities, etc.) and the geometric model into finite element analysis software (ANSYS, ABAQUS, etc.), perform mesh division on the model, select the appropriate mesh type (tetrahedral mesh, hexahedral mesh) and mesh density, and create a finite element model. In the finite element model, combine the collected material physical parameters and assign the corresponding material properties to the chip, bumps, and substrate respectively to ensure the accuracy of the simulation results. Define the thermal boundary conditions of the packaging structure, including heat sources (chip heating), heat dissipation paths (substrate, heat sink cover), and ambient temperature, and use the heat conduction equation to simulate the thermal distribution of the packaging structure under different temperature conditions, calculate the temperature field distribution, and then define the mechanical boundary conditions of the packaging structure, including fixed constraints (bottom of the substrate) and loads (thermal stresses caused by temperature changes). Use the elastic mechanics equation to simulate the deformation and stress distribution of the packaging structure under thermal stress. In the finite element analysis software, couple the thermal model and the mechanical model to obtain a thermal-mechanical coupling model, and then perform thermal-mechanical coupling analysis to simulate the behavior of the packaging structure under thermal-mechanical loads, including temperature changes, thermal expansion, stress distribution, and deformation conditions. Among them, the coupling method is to first perform a thermal analysis, calculate the temperature field distribution, and then input the temperature field results as loads into the mechanical model to calculate the stress and deformation;

[0070] Step 2: Using the established thermal-mechanical coupling model, perform thermal-mechanical coupling simulation and mechanical stress analysis on the packaging structure. Simulate and analyze the stress and deformation states of the packaging structure under temperature cycling, physical vibration, and mechanical shock conditions. Identify the stress concentration areas and the parts with large deformations, evaluate the impact on packaging reliability, and combine the requirements of flip-chip packaging to define the working conditions for thermal-mechanical coupling simulation and mechanical stress analysis, including temperature cycling condition, physical vibration condition, and mechanical shock condition. In the finite element analysis software, set the simulation parameters according to the defined working conditions to ensure that the boundary conditions, load conditions, and material properties of the model are consistent with the actual working conditions. Among them, the simulation parameters include temperature range, cycle period, vibration frequency, acceleration, shock acceleration, and shock duration. Definition of temperature cycling condition: The temperature change range is from -40°C to +125°C, and the cycle period is one cycle per hour, which is used to simulate the thermal expansion and contraction behavior of the packaging structure during temperature cycling. Definition of physical vibration condition: The vibration frequency is from 10 Hz to 500 Hz, and the acceleration is 10g, which is used to simulate the dynamic response of the packaging structure under periodic vibration. Definition of mechanical shock condition: The shock acceleration is 100g, and the shock duration is 11 ms, which is used to simulate the stress and deformation of the packaging structure under transient shock. Combine the established thermal-mechanical coupling model to perform thermal-mechanical coupling simulation on the packaging structure. According to the temperature cycling conditions in actual applications, set the temperature cycling curve in the simulation, define the heat generation power (10 W / cm²) in the chip area, define the heat dissipation paths of the substrate, heat sink cover, and air convection, and set the ambient temperature (25°C) and thermal boundary conditions (natural convection or forced convection). Then, use the finite element method to solve the heat conduction equation and calculate the temperature distribution of the packaging structure under different working conditions, so as to output the temperature field distribution results, including the temperature changes of the chip, bumps, and substrate. Combine the established thermal-mechanical coupling model to perform mechanical stress analysis on the packaging structure. Apply a fixed constraint at the bottom of the substrate to simulate the actual installation state of the packaging structure. Input the thermal-mechanical coupling simulation results (thermal stress caused by temperature change) as loads into the mechanical model, and apply corresponding dynamic loads (acceleration, impact force) to the physical vibration and mechanical shock conditions. Then, use the finite element method to solve the elastic mechanics equation and calculate the stress and deformation of the packaging structure under thermal stress, vibration, and shock loads, so as to output the stress distribution diagram and deformation diagram. Through the simulation results, identify the stress concentration areas, analyze the stress levels in the stress concentration areas, and judge whether they exceed the yield strength or fatigue limit of the material. Among them, the stress concentration areas include the connection between the chip and the substrate and the solder ball positions. Use the post-processing function of the finite element analysis software to output the stress distribution diagram of the packaging structure under different working conditions, and observe the stress distribution diagram to identify the parts where the stress values are significantly higher than the surrounding areas, and focus on potential stress concentration areas such as the connection between the chip and the substrate and the solder ball positions. Among them, the stress distribution diagram uses different colors to represent the magnitude of stress, and the darker the color, the greater the stress.After identifying the stress concentration area, the identified stress concentration area is locally enlarged to observe the stress distribution in more detail, and the stress gradient in the stress concentration area is analyzed, that is, the rate of change of the stress value in space. The high stress gradient area indicates local deformation or damage of the material, and the stress data of the stress concentration area is extracted, including the maximum stress value, the average stress value and the cyclic stress amplitude. The extracted maximum stress value is compared with the yield strength of the material. If the maximum stress value exceeds the yield strength of the material, it indicates that there is a risk of plastic deformation or fracture in the area. For temperature cycles and physical vibration cycles, the cyclic stress amplitude of the stress concentration area is analyzed, and the cyclic stress amplitude is compared with the fatigue limit of the material. If the cyclic stress amplitude exceeds the fatigue limit of the material, This indicates that there is a risk of fatigue failure in this area, and targeted design optimization suggestions can be made, including adjusting the geometric shapes of the chip and substrate, selecting more suitable materials, optimizing the position and size of the solder balls, etc., focusing on measures to reduce stress concentration and improve structural stability, analyzing the deformation distribution of the package structure, identifying the parts with large deformation, and evaluating the impact of deformation on the electrical connection and mechanical stability of the package structure. Deformation includes chip warping and substrate bending. Use the post-processing function of the finite element analysis software to output the deformation distribution map of the package structure under different working conditions (temperature cycle, physical vibration, mechanical shock), observe the deformation distribution map, and identify the parts with large deformation. The deformation distribution map uses different colors or heights to represent the size of the deformation. The darker the color or The higher the height, the greater the deformation. The deformation distribution of the chip area is analyzed, and attention is paid to the displacement difference between the center and the edge of the chip. Chip warping is manifested as the chip center bending upward or downward, resulting in an uneven chip surface. The maximum warping of the chip is extracted, and the maximum warping is expressed as the displacement value of the chip center. At the same time, the deformation distribution of the substrate area is observed, and attention is paid to the overall bending degree of the substrate. Substrate bending is manifested as the center of the substrate bending upward or downward, or the edge of the substrate warping. The maximum bending of the substrate is extracted, and the maximum bending is expressed as the displacement value of the center or edge of the substrate. The impact of chip warping on electrical connections is analyzed, including the reliability of solder ball connection and the risk of electrical short circuit or open circuit. Chip warping can easily lead to increased connection stress between the solder ball and the substrate, especially the solder ball at the edge of the chip. Position, analyze the stress distribution of the solder balls, and determine whether there is a risk of solder ball breakage or poor contact due to warping. If the solder ball stress exceeds the yield strength or fatigue limit of the material, it will cause electrical connection failure. Chip warping can easily lead to a reduction in the distance between adjacent solder balls, increasing the risk of electrical short circuits. At the same time, warping may also lead to poor contact between the solder balls and the substrate, increasing the risk of electrical short circuits. Evaluate the relationship between the amount of warping and the spacing between solder balls to determine whether there are potential electrical problems; and analyze the impact of substrate bending on electrical connections, including contact problems between substrate and chip and the reliability of solder balls. Substrate bending can easily lead to uneven contact between chip and substrate, affecting the reliability of electrical connections. Analyze the impact of substrate bending on the contact pressure between chip and substrate.Judge whether there is a risk of poor contact. If the substrate bending causes uneven contact pressure distribution between the chip and the substrate, it will lead to local electrical connection failure. Substrate bending is likely to cause the solder balls to bear additional shear stress, affecting the reliability of the solder balls. Analyze the stress distribution of the solder balls to judge whether there is a risk of solder ball fracture or fatigue failure caused by substrate bending. If the shear stress of the solder balls exceeds the yield strength or fatigue limit of the material, it will lead to electrical connection failure. Analyze the impact of chip warping on mechanical stability, including the mechanical stability of the package structure and the fatigue life of the material. Chip warping is likely to cause a decrease in the overall mechanical stability of the package structure, especially when subjected to external loads (vibration, shock). Analyze the impact of chip warping on the overall stiffness of the package structure and judge whether there is a risk of structural instability. If chip warping causes a significant reduction in the stiffness of the package structure, it will undergo greater deformation under the action of external loads, further affecting the reliability of the package. Chip warping is likely to cause the material to bear cyclic stress, affecting the fatigue life of the material. Use the S-N curve to evaluate the fatigue life of the material under warping stress and judge whether there is a risk of fatigue failure. If the warping stress exceeds the fatigue limit of the material, it will lead to fatigue fracture of the material during long-term use; Analyze the impact of substrate bending on mechanical stability, including the overall stability of the package structure and the fatigue life of the material. Substrate bending is likely to cause a decrease in the overall stability of the package structure, especially when subjected to external loads (such as vibration, shock). Analyze the impact of substrate bending on the overall stiffness of the package structure and judge whether there is a risk of structural instability. If substrate bending causes a significant reduction in the stiffness of the package structure, it will undergo greater deformation under the action of external loads, further affecting the reliability of the package. Substrate bending is likely to cause the material to bear cyclic stress, affecting the fatigue life of the material. Use the S-N curve to evaluate the fatigue life of the material under bending stress and judge whether there is a risk of fatigue failure. If the bending stress exceeds the fatigue limit of the material, it will lead to fatigue fracture of the material during long-term use. According to the stress concentration area and the parts with large deformation, evaluate the failure risk of the package structure under temperature cycle, physical vibration and mechanical shock conditions. Among them, the failure modes of the failure risk include solder ball fracture or fatigue failure, poor contact between the chip and the substrate, substrate cracking or delamination, and electrical short circuit or open circuit caused by chip warping. Furthermore, use the S-N curve to evaluate the fatigue life of the solder balls and the package structure, and combine the stress level and deformation conditions to predict the reliable working time of the package structure. For the evaluation of the failure risk, including solder ball fracture or fatigue failure, poor contact between the chip and the substrate, substrate cracking or delamination, and electrical short circuit or open circuit caused by chip warping. Among them, for solder ball fracture or fatigue failure, through the stress distribution diagram, identify the stress concentration situation at the solder ball position, analyze the maximum stress value of the solder ball, judge whether it exceeds the yield strength or fatigue limit of the solder ball material, and use the S-N curve (fatigue life curve) to evaluate the fatigue life of the solder ball under cyclic stress.Predict the fatigue failure time of solder balls by combining the stress level and the number of cycles; for poor contact between the chip and the substrate, analyze the deformation between the chip and the substrate, identify whether there is a risk of poor contact, focus on the contact problems caused by chip warping and substrate bending, use finite element analysis software to calculate the contact pressure distribution between the chip and the substrate, judge whether the contact pressure is uniform, and whether there is a risk of poor contact due to too low local contact pressure; for substrate cracking or delamination, analyze the stress distribution of the substrate, identify whether there is an area with too high stress, focus on the stress concentration at the edge of the substrate and the position of the solder balls, compare the maximum stress value of the substrate with the fracture strength of the material to judge whether there is a risk of substrate cracking or delamination; for electrical short circuit or open circuit caused by chip warping, analyze the warping of the chip, identify whether the distance between adjacent solder balls is reduced, increasing the risk of electrical short circuit. At the same time, analyze whether chip warping causes poor contact between the solder ball and the substrate, increasing the risk of electrical open circuit. Use finite element analysis software to calculate the electric field distribution between the solder balls to judge whether there is a risk of electrical short circuit due to too strong electric field. Use the S-N curve to evaluate the fatigue life of the solder balls and the package structure under cyclic stress, combine the stress level and the number of cycles to predict the fatigue failure time of the solder balls and the package structure, combine the stress level and deformation of the stress concentration area to evaluate the reliability of the package structure, focus on the stress and deformation at the position of the solder balls, and the contact between the chip and the substrate, and predict the reliable working time of the package structure according to the fatigue life evaluation result;

[0071] The calculation expression for the fatigue failure time is:

[0072] ;

[0073] In the formula, is the fatigue failure time, is the number of different stress levels, is the th stress level, is the number of cycles at the stress level , is a material constant related to the fatigue limit of the material, is the fatigue index of the material, describing the influence of the stress level on the fatigue life, usually between 2 and 10, is the fatigue life index, describing the influence of the number of cycles on the fatigue life, usually between 3 and 10, between 100 and 1000 MPa, and the specific value depends on the fatigue limit of the material. A higher value indicates that the material has a higher fatigue limit and a longer fatigue life;

[0074] The calculation expression for the reliable working time of the package structure is:

[0075] ;

[0076] Wherein, is the reliable working time of the encapsulation structure, is the th strain level, usually between 0.001 and 0.01;

[0077] Step 3: Based on the results of thermo-mechanical coupling analysis, perform optimization design of the encapsulation structure, including adjusting the geometries of the chip and substrate, material selection, thermal management optimization, and contact stability optimization, to reduce stress concentration and deformation. The goal is to improve the thermal management effect and optimize the stress distribution to make the contact between the chip and the substrate more stable;

[0078] Step 4: After the optimization design, perform thermo-mechanical coupling effect analysis on the optimized encapsulation structure again to verify whether the optimization effect meets the design requirements. If the optimization effect is not ideal, return to Step 3 to continue adjusting the design parameters until the requirements are met;

[0079] Step 5: Combine the optimized design parameters that meet the design requirements, perform prototype manufacturing and testing to verify the accuracy of the simulation results. Among them, the testing process includes temperature cycle testing, mechanical shock testing, and reliability testing, etc., to verify its performance in actual applications;

[0080] Step 6: If the prototype manufacturing and testing are passed, implement mass production using the optimized design parameters and apply the flip-chip FC packaging technology to actual products. Otherwise, return to Step 2 to continue performing thermo-mechanical coupling effect analysis until the flip-chip packaging requirements are met.

[0081] Example 2, as Figure 1 , Figure 2 shown, based on Example 1, the present invention provides a technical solution: Preferably, Step 3 specifically includes:

[0082] Based on the stress concentration areas identified from the thermo-mechanical coupling analysis results and the deformation analysis results, determine the optimization objectives for the package structure design, including improving thermal management effectiveness, optimizing stress distribution, and ensuring firm contact between the chip and the substrate. Improving thermal management effectiveness ensures the stable operation of the package structure in high-temperature environments. Optimizing stress distribution reduces stress concentration and deformation, extending the service life of the package structure. Ensuring firm contact between the chip and the substrate improves the reliability and electrical performance of the package. For the determined optimization objectives, match the corresponding optimization design measures, including adjusting the geometries of the chip and the substrate, material selection, thermal management optimization, and contact stability optimization. Among them, optimize the thickness, size, and shape of the chip and the substrate to reduce stress concentration and deformation. Increase the thickness of the substrate or adjust the edge design of the chip to reduce warping. Optimize the layout and size of the solder balls to reduce stress concentration. Increase the solder ball pitch or adjust the solder ball diameter to ensure that the solder balls can evenly withstand stress during thermal expansion and contraction. Select a substrate material with a coefficient of thermal expansion (CTE) that better matches the chip to reduce stress caused by thermal expansion differences. Materials such as copper or aluminum carbide can be used as the main body of the substrate. Select materials with high thermal conductivity to improve thermal management effectiveness and reduce the chip operating temperature. Add a heat sink cover or microchannel cooling technology to the package structure to improve the heat dissipation efficiency. Optimize the heat dissipation design of the substrate to ensure that heat can be quickly conducted. By optimizing the heat dissipation path of the package structure, reduce the impact of the ambient temperature on the package structure. Metallize the chip and the substrate and strictly clean the surfaces to ensure good contact. Use a high-precision chip bonding process to ensure tight contact between the chip and the substrate. Before aligning the chip with the substrate, preheat the chip to the standby temperature (220°C) to reduce thermal expansion differences. Use vacuum adsorption technology to ensure that the substrate remains flat during the chip bonding process. Use the optimized design parameters to re-perform the finite element analysis and update the finite element simulation model;

[0083] Step 4 specifically includes:

[0084] Combined with the updated finite element simulation model, the thermo-mechanical coupling effect analysis is carried out again on the optimized packaging structure. The simulation analyses of thermal-mechanical coupling analysis and mechanical stress analysis are performed. According to the simulation analysis results, clarify the stress distribution, temperature distribution and deformation of the optimized packaging structure under thermal and mechanical loads, extract the results of the finite element analysis, including stress diagrams, temperature diagrams and deformation diagrams, compare the results before and after optimization, evaluate the impact of the optimization measures on the thermal management effect, stress distribution and contact stability, and judge whether the optimization effect meets the requirements according to the design requirements of the maximum stress limit, maximum temperature limit and maximum deformation limit. If the optimization effect is ideal, that is, the stress concentration is reduced, the temperature distribution is more uniform, the deformation amount is reduced, and the contact stability is improved, then it is judged that the optimization effect meets the design requirements and proceed to the next step. If the optimization effect is not ideal, that is, the stress is still concentrated, the temperature distribution is uneven, the deformation amount is too large or the contact stability is insufficient, then return to step three to continue adjusting the design parameters, implement the design parameter adjustment measures including geometric shape adjustment, material selection optimization, thermal management improvement and contact stability improvement, and use the updated design parameters to re-perform the finite element analysis to verify the optimization effect until the optimized packaging structure meets the design requirements;

[0085] Step five specifically includes:

[0086] According to the finite element simulation analysis results, determine the optimized design parameters that meet the design requirements, including geometric shape, material selection, thermal management strategy, contact stability optimization measures, etc. And according to the optimized design parameters, formulate a detailed prototype manufacturing plan, including manufacturing process, processing equipment, material procurement, quality control, etc. Combining the formulated prototype manufacturing plan, formulate a test plan including temperature cycle test, mechanical shock test and reliability test, and clarify the test purpose, test conditions, test equipment and test standards. Among them, for the temperature cycle test, the test purpose is to evaluate the tolerance of the package structure under rapid conversion between extreme high and low temperatures, and simulate the temperature change environment that the product may encounter in actual use. The test conditions are that the high and low temperature range is between -40°C and +125°C, the temperature change rate is 10°C / min, the number of cycles is 15 or more, and the equilibrium time is to maintain for 30 minutes at each temperature point. The test equipment is to use a high and low temperature alternating test chamber or a high and low temperature alternating damp heat test chamber to ensure that the equipment can quickly and accurately switch the temperature. The test standard is to check the appearance of the package structure for cracks, deformation or material peeling, test the electrical performance to ensure normal function after temperature cycling, and analyze the data to evaluate the thermal stability of the material and structure; for the mechanical shock test, the test purpose is to simulate the shocks that the product may encounter during transportation and use, and evaluate its shock resistance. The test conditions are that the peak acceleration is 100g, the pulse duration is 11ms, the waveform selection is half sine wave, trapezoidal wave or triangular wave, and the number of shocks is 3 times for each surface, a total of 18 times. The test equipment is to use professional mechanical shock test equipment to ensure that the equipment can provide accurate shock waveforms and accelerations. The test standard is to check the appearance of the package structure for cracks, deformation or damage, test the electrical performance to ensure normal function after shock, and analyze the data to evaluate the integrity and reliability of the structure;For reliability testing, the purpose of the test is to comprehensively evaluate the long-term stability of the package structure under various environmental conditions. The test conditions are high-temperature storage test and high-temperature and high-humidity bias test. The high-temperature storage test is to store for a certain period of time in a high-temperature environment (85°C), and the high-temperature and high-humidity bias test is to conduct a bias test under high-temperature and high-humidity conditions (85°C / 85% humidity). The test standard is to analyze the data, evaluate the reliability of the package structure during long-term use, ensure that the product can still work normally under extreme conditions, sort out the result data of temperature cycle test, mechanical shock test and reliability test, analyze the test results, compare the consistency between the performance of the prototype in actual test and the simulation results, and evaluate the performance of the prototype in actual application, including thermal management performance, mechanical strength, shock resistance and long-term reliability. According to the test results, judge the accuracy of the simulation results. If the test results are consistent with the simulation results, it indicates that the simulation model is accurate and reliable and can be used to guide subsequent design and optimization. If there are differences between the test results and the simulation results, analyze the reasons for the differences. The reasons for the differences include the simplification of the simulation model, the differences in test conditions or the errors in the manufacturing process, etc., and then modify and improve the simulation model;

[0087] Step six specifically includes:

[0088] Analyze the test results of prototype manufacturing. If the temperature cycle test, mechanical shock test and reliability test meet the required standards, it is considered that the test is passed and meets the design requirements, and then enter the mass production stage. Among them, the process of implementing mass production is: according to market demand and order quantity, formulate a detailed production plan, determine the production batches, production schedule and resource allocation, and then carry out the full-process production cycle of production preparation, production process control, product inspection and packaging, and product delivery and after-sales service. The requirement standard for the temperature cycle test is that there are no cracks, deformations or material spalling in the package structure under rapid conversion of extreme high and low temperatures, and the electrical performance remains normal after the temperature cycle, and the data analysis shows that the material and structure have good thermal stability; the requirement standard for the mechanical shock test is that there are no cracks, deformations or damages in the package structure after impact, and the electrical performance remains normal after impact, and the data analysis shows that the structure has good integrity and reliability; the requirement standard for the reliability test is that there is no obvious degradation in the package structure after high-temperature storage and high-temperature and high-humidity bias tests, and the electrical performance remains normal after long-term tests, and the data analysis shows that the package structure has good long-term stability under extreme conditions. If the prototype manufacturing and test results do not meet the required standards, it is considered that the test is not passed, and it is necessary to return to the optimization design step and continue the optimization process of thermal-mechanical coupling effect analysis, design optimization, and remanufacturing and testing the prototype. If the new prototype still does not meet the design requirements, continue to return to step two for thermal-mechanical coupling effect analysis until the flip-chip package requirements are met. Through continuous cycle iteration, gradually optimize the design of the package structure to ensure its stability and reliability in actual application.

[0089] As described above, it is only the specific implementation manner of the present application. However, the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claimed rights.

Claims

1. A flip-chip FC packaging technology method, characterized in that, It includes the following steps: Step 1: Collect the material physical parameters of the flip chip package and establish a thermal-mechanical coupling model; Step 2: Use the established thermal-mechanical coupling model to conduct thermal-mechanical coupling simulation and mechanical stress analysis on the package structure, identify the stress concentration areas and the parts with large deformations, and combine the requirements of the flip chip package to define the working conditions of the thermal-mechanical coupling simulation and mechanical stress analysis, including temperature cycle condition, physical vibration condition and mechanical shock condition, and set the simulation parameters in the finite element analysis software according to the defined working conditions. Among them, the simulation parameters include temperature range, cycle period, vibration frequency, acceleration, shock acceleration and shock duration; Combine the established thermal-mechanical coupling model to conduct thermal-mechanical coupling simulation on the package structure, set the temperature cycle curve in the simulation according to the temperature cycle condition in the actual application, and then use the finite element method to solve the heat conduction equation to calculate the temperature distribution of the package structure under different working conditions, so as to output the temperature field distribution results, including the temperature changes of the chip, bumps and substrate; Combine the established thermal-mechanical coupling model to conduct mechanical stress analysis on the package structure, apply fixed constraints at the bottom of the substrate to simulate the actual installation state of the package structure, input the thermal-mechanical coupling simulation results as loads into the mechanical model, and apply corresponding dynamic loads to the physical vibration and mechanical shock conditions, and then use the finite element method to solve the elastic mechanics equation to calculate the stress and deformation of the package structure under thermal stress, vibration and shock loads, so as to output the stress distribution diagram and deformation diagram; Through the simulation results, identify the stress concentration areas, analyze the stress levels in the stress concentration areas, and judge whether they exceed the yield strength or fatigue limit of the material. Among them, the stress concentration areas include the connection between the chip and the substrate and the solder ball positions; Analyze the deformation distribution of the package structure, identify the parts with large deformations, and evaluate the impact of the deformation on the electrical connection and mechanical stability of the package structure. Among them, the deformation includes chip warping and substrate bending; According to the stress concentration areas and the parts with large deformations, evaluate the failure risks of the package structure under temperature cycle, physical vibration and mechanical shock conditions. Among them, the failure modes of the failure risks include solder ball fracture or fatigue failure, poor contact between the chip and the substrate, substrate cracking or delamination, and electrical short circuit or open circuit caused by chip warping. Then use the S-N curve to evaluate the fatigue life of the solder balls and the package structure, and combine the stress level and deformation situation to predict the reliable working time of the package structure; Step 3: Based on the thermal-mechanical coupling analysis results, conduct optimization design of the package structure; Step 4: After the optimization design, conduct thermal-mechanical coupling effect analysis on the optimized package structure again to verify whether the optimization effect meets the design requirements. If the optimization effect is not ideal, return to Step 3 to continue adjusting the design parameters until the requirements are met; Step 5: Combine the optimized design parameters that meet the design requirements to conduct prototype manufacturing and testing to verify the accuracy of the simulation results; Step 6: If the prototype manufacturing and testing are passed, implement mass production using the optimized design parameters and apply the flip-chip FC packaging technology to the actual product. Otherwise, return to Step 2 to continue the thermo-mechanical coupling effect analysis until the flip-chip packaging requirements are met.

2. The method for flip chip FC packaging technology according to claim 1, characterized in that: The specific content of Step 1 includes: Traverse the technical specifications, data manuals, and industry standards in the field of electronic packaging to obtain the material physical parameters of flip-chip packaging, including the thermal expansion coefficients, elastic moduli, and thermal conductivities of the chip material, substrate material, and solder ball material; Use 3D modeling software to construct the geometric model of flip-chip packaging. The geometric model is a complete packaging structure including the chip, bumps, and substrate, and import the collected material physical parameters and geometric model into the finite element analysis software, perform mesh division on the model, and create a finite element model; In the finite element model, combine the collected material physical parameters and assign corresponding material properties to the chip, bumps, and substrate respectively; Define the thermal boundary conditions of the packaging structure, including heat sources, heat dissipation paths, and ambient temperature, and use the heat conduction equation to simulate the thermal distribution of the packaging structure under different temperature conditions, calculate the temperature field distribution, and then define the mechanical boundary conditions of the packaging structure, including fixed constraints and loads, and use the elastic mechanics equation to simulate the deformation and stress distribution of the packaging structure under thermal stress; In the finite element analysis software, couple the thermal model and the mechanical model to obtain a thermo-mechanical coupling model, and then perform thermo-mechanical coupling analysis to simulate the behavior of the packaging structure under thermo-mechanical loads, including temperature changes, thermal expansion, stress distribution, and deformation conditions.

3. The flip chip FC packaging technology method according to claim 1, characterized in that: Definition of the temperature cycle condition: The temperature change range is from -40°C to +125°C, and the cycle period is one cycle per hour, which is used to simulate the thermal expansion and contraction behavior of the packaging structure during the temperature cycle; Definition of the physical vibration condition: The vibration frequency is from 10Hz to 500Hz, and the acceleration is 10g, which is used to simulate the dynamic response of the packaging structure under periodic vibration; Definition of the mechanical shock condition: The shock acceleration is 100g, and the shock duration is 11ms, which is used to simulate the stress and deformation of the packaging structure under transient shock.

4. The method of flip chip FC packaging technology according to claim 3, characterized in that: The process of identifying the stress concentration area is: Use the post-processing function of the finite element analysis software to output the stress distribution diagrams of the packaging structure under different conditions, observe the stress distribution diagrams, and identify the parts where the stress values are significantly higher than the surrounding areas; After identifying the stress concentration area, locally magnify the identified stress concentration area, analyze the stress gradient of the stress concentration area, and extract the stress data of the stress concentration area, including the maximum stress value, average stress value, and cyclic stress amplitude; Compare the extracted maximum stress value with the yield strength of the material. If the maximum stress value exceeds the yield strength of the material, it indicates that there is a risk of plastic deformation or fracture in this area. For the temperature cycle and physical vibration cycle conditions, analyze the cyclic stress amplitude of the stress concentration area and compare the cyclic stress amplitude with the fatigue limit of the material. If the cyclic stress amplitude exceeds the fatigue limit of the material, it indicates that there is a risk of fatigue failure in this area; The process of identifying the parts with large deformation is as follows: Use the post-processing function of finite element analysis software to output the deformation distribution diagrams of the packaging structure under different working conditions, observe the deformation distribution diagrams, and identify the parts with large deformation; Analyze the deformation distribution in the chip area, pay attention to the displacement difference between the center and the edge of the chip, and extract the maximum warpage amount of the chip, which is represented by the displacement value at the center of the chip. At the same time, observe the deformation distribution in the substrate area, pay attention to the overall bending degree of the substrate, and extract the maximum bending amount of the substrate, which is represented by the displacement value at the center or the edge of the substrate; Analyze the influence of chip warpage on electrical connection, including the reliability of solder ball connection and the risk of electrical short circuit or open circuit, and analyze the influence of substrate bending on electrical connection, including the contact problem between the substrate and the chip and the reliability of solder balls; Analyze the influence of chip warpage on mechanical stability, including the mechanical stability of the packaging structure and the fatigue life of the material, and analyze the influence of substrate bending on mechanical stability, including the overall stability of the packaging structure and the fatigue life of the material.

5. A flip-chip FC packaging technology method according to claim 4, characterized in that: The process of failure risk and predicting the reliable working time of the packaging structure is as follows: For the assessment of failure risk, it includes solder ball fracture or fatigue failure, poor contact between the chip and the substrate, substrate cracking or delamination, and electrical short circuit or open circuit caused by chip warpage; Use the S-N curve to evaluate the fatigue life of solder balls and the packaging structure under cyclic stress, and combine the stress level and the number of cycles to predict the fatigue failure time of solder balls and the packaging structure; Combine the stress level and deformation conditions in the stress concentration area to evaluate the reliability of the packaging structure, focus on the stress and deformation at the solder ball position, and the contact situation between the chip and the substrate, and predict the reliable working time of the packaging structure according to the fatigue life assessment results.

6. A flip-chip FC packaging technology method according to claim 5, characterized in that: Step three specifically includes: Combine the stress concentration area identified by the thermo-mechanical coupling analysis results and the deformation analysis results to determine the optimization objectives for the optimized design of the packaging structure, including improving the thermal management effect, optimizing the stress distribution, and ensuring the firm contact between the chip and the substrate; For the determined optimization objectives, match the corresponding optimized design measures, including adjusting the geometric shapes of the chip and the substrate, material selection, thermal management optimization, and contact stability optimization; Use the optimized design parameters to re-perform finite element analysis and update the finite element simulation model.

7. A flip-chip FC packaging technology method according to claim 6, characterized in that: Step four specifically includes: Combine the updated finite element simulation model to perform a thermo-mechanical coupling effect analysis on the optimized packaging structure again, and perform simulation analyses of thermo-mechanical coupling analysis and mechanical stress analysis; According to the simulation analysis results, clarify the stress distribution, temperature distribution, and deformation conditions of the optimized packaging structure under thermal and mechanical loads; Extract the results of finite element analysis, including stress diagrams, temperature diagrams, and deformation diagrams, compare the results before and after optimization, evaluate the influence of the optimization measures on the thermal management effect, stress distribution, and contact stability, and judge whether the optimization effect meets the requirements according to the design requirements of the maximum stress limit, maximum temperature limit, and maximum deformation limit. If the optimization effect is ideal, that is, the stress concentration is reduced, the temperature distribution is more uniform, the deformation amount is decreased, and the contact stability is improved, it is determined that the optimization effect meets the design requirements and proceed to the next step; If the optimization effect is not ideal, that is, the stress is still concentrated, the temperature distribution is uneven, the deformation amount is too large, or the contact stability is insufficient, return to step three to continue adjusting the design parameters, implement design parameter adjustment measures including geometric shape adjustment, material selection optimization, thermal management improvement, and contact stability improvement, and use the updated design parameters to re-perform the finite element analysis to verify the optimization effect until the optimized package structure meets the design requirements.

8. A flip chip FC packaging technology method according to claim 7, characterized in that: The specific steps of step five include: According to the finite element simulation analysis results, determine the optimized design parameters that meet the design requirements, and formulate a detailed prototype manufacturing plan based on the optimized design parameters; Combined with the formulated prototype manufacturing plan, formulate a test plan including temperature cycle test, mechanical shock test, and reliability test, and clarify the test purpose, test conditions, test equipment, and test standards; Sort out the result data of the temperature cycle test, mechanical shock test, and reliability test, analyze the test results, compare the consistency between the performance of the prototype in the actual test and the simulation results, and evaluate the performance of the prototype in actual applications, including thermal management performance, mechanical strength, shock resistance, and long-term reliability; According to the test results, judge the accuracy of the simulation results. If the test results are consistent with the simulation results, it indicates that the simulation model is accurate. If there are differences between the test results and the simulation results, analyze the reasons for the differences, and then modify and improve the simulation model.

9. A flip chip FC packaging technology method according to claim 8, characterized in that: The specific steps of step six include: Analyze the test results of the prototype manufacturing. If the temperature cycle test, mechanical shock test, and reliability test meet the required standards, it is considered that the test passes and meets the design requirements, and then enter the mass production stage; If the prototype manufacturing and test results do not meet the required standards, it is considered that the test fails and it is necessary to return to the optimization design step to continue the optimization process of thermal-mechanical coupling effect analysis, design optimization, and remanufacturing and testing of the prototype. If the new prototype still does not meet the design requirements, continue to return to step two for thermal-mechanical coupling effect analysis until the flip-chip packaging requirements are met. Through continuous cycle iteration, gradually optimize the design of the package structure.

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