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CN-121980869-A - Geometric-process comprehensive parameter optimization method, system and equipment for BGA welding spot reflow soldering

CN121980869ACN 121980869 ACN121980869 ACN 121980869ACN-121980869-A

Abstract

The invention discloses a geometric-process comprehensive parameter optimization method, a system and equipment for reflow soldering of a BGA welding spot, which are characterized by designing a geometric model of the BGA welding spot, storing data as a form as a data set based on a preset geometric-process parameter level, carrying out finite element simulation of a reflow process by using an orthogonal test method to obtain a deformation value of the welding spot, carrying out range analysis to obtain the geometric-process parameter level corresponding to the minimum deformation of the welding spot after reflow soldering, carrying out finite element simulation to obtain the minimum deformation, carrying out weight analysis to obtain significant parameters and sequencing, realizing rapid optimization of the geometric structure and the reflow process parameters of the welding spot under the simulation result of a limited number of times, simultaneously evaluating each geometric-process to reduce the deformation value of the welding spot after reflow soldering, obtaining the weight of each geometric-process parameter, and determining the key optimized parameter, thereby providing a certain reference meaning for the actual reflow soldering process.

Inventors

  • DING SUNAN
  • Qiu Kungui
  • LI YANSONG
  • Ding Yecheng

Assignees

  • 南京大学

Dates

Publication Date
20260505
Application Date
20260128

Claims (10)

  1. 1. The geometric-process comprehensive parameter optimization method for reflow soldering of the BGA welding spots is characterized by comprising the following steps of: (1) Designing a geometric model of the BGA welding spot, obtaining a parameter level of a preset geometric-technological parameter corresponding to reflow soldering of the BGA welding spot according to the model, and carrying out finite element simulation to obtain an initial deformation value of the welding spot after reflow soldering; (2) Generating a value range of the geometric-technological parameter level based on a preset geometric-technological parameter level, uniformly generating a plurality of groups of geometric-technological parameter levels in the value range, and storing the data as a form as a data set; (3) Carrying out finite element simulation of a reflow process on different geometric-technological parameter levels on the data set by using an orthogonal test method according to the obtained data set to obtain deformation values of welding spots; (4) Performing extremely poor analysis according to the obtained deformation value to obtain a geometric-technological parameter level corresponding to the solder joint when the deformation of the solder joint after reflow soldering is minimum, and performing reflow soldering finite element simulation of the solder joint according to the corresponding geometric-technological parameter level to obtain the minimum deformation; (5) And according to the obtained deformation values, carrying out weight analysis on the influence generated by the deformation of the welding spot after the reflow soldering on different geometric-technological parameters to obtain parameters with obvious influence, and sequencing the influence weights of the parameters.
  2. 2. The method for optimizing geometry-process parameters of reflow soldering of BGA solder joints according to claim 1, wherein in step (1), the finite element simulation is that reflow soldering simulation is performed on a BGA interconnection structure based on a thermosetting coupling model, and a solder joint deformation value corresponding to an initial geometry-process parameter level is obtained.
  3. 3. The method for optimizing geometry-process parameters of reflow soldering of BGA solder joints according to claim 1, wherein step (2) comprises determining a range of values of solder joint height, solder joint diameter, solder joint pitch parameter level and a range of values of solder joint cooling rate parameter level from the obtained geometry-process parameter levels, and generating a plurality of sets of parameter levels of solder joint height, solder joint diameter, solder joint pitch and reflow soldering cooling rate uniformly according to an arithmetic distribution according to the range of values.
  4. 4. The method for optimizing geometry-process parameters of reflow soldering of BGA solder joints according to claim 1, wherein step (3) comprises grouping parameter levels of each influencing parameter in the data by using an orthogonal test method, performing a thermosetting coupling reflow process simulation on each group of solder joint height, diameter, spacing and cooling rate on the data set to obtain solder joint deformation values after reflow soldering, and adding the data to the data set.
  5. 5. The geometric-technological comprehensive parameter optimization method for reflow soldering of BGA welding spots according to claim 1 is characterized in that the step (4) is specifically that the extremely poor analysis is carried out based on a data set, the corresponding K value is calculated according to each parameter level, the minimum K value is obtained based on each parameter, so that the optimal parameter combination of the welding spots, namely the geometric-technological parameter level corresponding to the minimum deformation value, is obtained, the finite element simulation is carried out based on the geometric-technological parameter level, the minimum deformation of the welding spots is obtained, and the geometric-technological parameter level corresponding to the minimum deformation value and the minimum deformation value are added into the data set.
  6. 6. The geometric-process comprehensive parameter optimization method for BGA welding spot reflow soldering of claim 1, wherein the step (5) is specifically to calculate the dispersion square sum S, the degree of freedom dfi, the mean square M, the contribution ratio and the F value corresponding to each parameter according to a data set. And under the condition of 90% confidence level, judging whether the deformation value of the welding spot after the welding spot is subjected to reflow soldering by geometric-technological parameters according to the corresponding F0.1 value, and sequencing the significance degree of the influence of the geometric-technological parameters on the deformation value according to the F value, wherein the calculation formula of the deviation square sum S is as follows Ki is the sum of all deformation values of each parameter level, m is the number of influencing parameters, For the number of horizontal deformation values for each parameter, N is the number of all deformation values, and the degree of freedom of the dispersion square sum is Mean square M is F value is 。
  7. 7. A system for a geometry-process complex parameter optimization method according to claim 1, wherein the system comprises an initial parameter acquisition unit, an orthogonal parameter generation unit, a finite element simulation unit, a minimum deformation value acquisition unit and a parameter evaluation unit.
  8. 8. The system according to claim 7, characterized in that it comprises in particular the following: the initial parameter obtaining unit comprises a step of obtaining initial geometric parameter levels of welding spots, such as height, diameter and interval, and a step of obtaining the cooling rate of a reflow soldering temperature curve of the welding spots; The orthogonal parameter generating unit comprises a step of generating a value range of key geometric-technological parameter levels of the welding spot based on initial parameters, uniformly generating a plurality of groups of specific parameter levels in the value range, and storing the specific parameter levels as a data set; the finite element simulation unit performs finite element simulation on the welding point based on the initial parameter level and the specific parameter level generated by the orthogonal test method, acquires deformation of the welding point after reflow soldering, and adds deformation values into a data set; The minimum deformation value acquisition unit comprises performing extremely poor analysis based on the data set, and acquiring an optimal parameter combination of the welding spot according to the minimum K value of each parameter, namely, the geometric-technological parameter level corresponding to the minimum deformation value; The parameter evaluation unit comprises calculating the corresponding deviation square sum, the degree of freedom, the mean square, the contribution ratio and the F value of each parameter level according to the data set, judging whether the deformation value of the welding spot after the welding spot reflow soldering is obvious or not according to the corresponding F0.1 value under the condition of 90% confidence level, and sequencing the influence significance degree of the relative deformation value of the geometric-process parameter according to the F value.
  9. 9. An apparatus for use in a geometry-process combination parameter optimization method according to claim 1, comprising a processor, a memory unit and a bus, the processor and the memory unit being in data communication via the bus.
  10. 10. The apparatus of claim 9, wherein the processor is responsible for reading initial parameter levels, performing finite element simulation operations, performing range analysis, parameter impact significance determination, and the like, and the memory unit is responsible for storing initial parameter levels for the solder joints, parameter level tables generated by orthogonal experimentation, and corresponding finite element simulation results, and storing operating instructions executable by the processor.

Description

Geometric-process comprehensive parameter optimization method, system and equipment for BGA welding spot reflow soldering Technical Field The invention relates to a method for reflow soldering of a BGA welding spot, in particular to a geometric-process comprehensive parameter optimization method for reflow soldering of a BGA welding spot, and also relates to a system and equipment adopting the method. Background When an electronic product works in a complex environment, the electronic product is affected by environmental factors such as temperature, vibration, dust, humidity and the like, and the factors can damage the working performance of the electronic product and even lead to product failure in extreme cases. Among them, failure of the interconnection structure is one of the main causes of failure of the electronic product. In the reflow soldering process, defects of the post-soldering interconnection structure are easily caused due to the limitation of component materials such as chips and substrates and the influence of factors such as temperature, time, speed and clamp cooperation in the process. These defects may include cracks caused by excessive residual stress of the solder joint, form shifts caused by misplacement of upper and lower pads, bridging caused by excessive solder, and the like, and in severe cases, the solder joint may fail. Therefore, reflow soldering is a key step for ensuring the quality of electronic products, and in order to avoid these problems, it is necessary to deeply study the geometric parameters of the interconnection solder joints and the influence mechanism of the reflow process parameters on the deformation of the solder joints after soldering, and accordingly, comprehensively optimize the two parameters. The method is beneficial to reducing the form offset of the welding spots after welding, thereby improving the reliability and the service life of the interconnection welding spots, shortening the research and development period and reducing the research and development cost. The optimization of the current reflow soldering process is mainly focused on the aspects of material selection, geometric parameter optimization, process improvement and the like of the welding spots, and the residual stress and deformation of the welding spots are reduced through the optimization of the materials, parameters and the process, so that the service life of the welding spots is prolonged. However, the cost of experimental test for improving the material and welding spot process is huge, the geometrical parameters and the process parameters of the welding spot have influences, and the influence degree of each parameter cannot be visually presented. How to quickly position the optimal geometric-technological parameters and acquire the influence degree of each geometric and technological parameter on the deformation of the welding spots is an important ring for realizing the reduction of experimental cost and the improvement of the reflow soldering technological level. Disclosure of Invention The invention aims to provide a geometric-process comprehensive parameter optimization method for BGA welding spot reflow soldering, and also provides a system and equipment adopting the method. The invention relates to a geometric-process comprehensive parameter optimization method for BGA welding spot reflow soldering, which comprises the following steps: (1) Designing a geometric model of the BGA welding spot, obtaining a parameter level of a preset geometric-technological parameter corresponding to reflow soldering of the BGA welding spot according to the model, and carrying out finite element simulation to obtain an initial deformation value of the welding spot after reflow soldering; (2) Generating a value range of the geometric-technological parameter level based on a preset geometric-technological parameter level, uniformly generating a plurality of groups of geometric-technological parameter levels in the value range, and storing the data as a form as a data set; (3) Carrying out finite element simulation of a reflow process on different geometric-technological parameter levels on the data set by using an orthogonal test method according to the obtained data set to obtain deformation values of welding spots; (4) Performing extremely poor analysis according to the obtained deformation value to obtain a geometric-technological parameter level corresponding to the solder joint when the deformation of the solder joint after reflow soldering is minimum, and performing reflow soldering finite element simulation of the solder joint according to the corresponding geometric-technological parameter level to obtain the minimum deformation; (5) And according to the obtained deformation values, carrying out weight analysis on the influence generated by the deformation of the welding spot after the reflow soldering on different geometric-technological parameters to obtain parameters with obvious influe