BGA (Ball Grid Array) welding spot structure parameter optimization method for reducing power cyclic stress

Abstract

The invention discloses a BGA (Ball Grid Array) welding spot structure parameter optimization method for reducing a power cyclic stress. The method comprises the following steps that: 1) establishinga COMSOL welding spot simulation analysis model; 2) obtaining the thermal stress value of a welding spot; 3) determining the influence factor of the thermal stress value; 4) determining a parameter level value of the influence factor; 5) obtaining an experiment sample; 6) obtaining a function relational expression between the influence factor and the thermal stress value; 7) carrying out regression analysis on the function relational expression to obtain a regression equation; 8) determining the correctness of the function relational expression; 9) adopting a random way to generate an initialpopulation; 10) obtaining a current evolution algebra gen and an optimal fitness value; 11) randomly forming M / 2 groups of paired individuals by M individuals, and carrying out an interlace operationon each group of paired individuals; 12) carrying out a mutation operation on the paired individuals; 13) carrying out evolution reversion on the paired individuals; 14) selecting the individual withthe optimal fitness value; and 15) after the population is updated, carrying out judgment again. The method has the advantages of good robust performance and simple calculation method, and great convenience is brought to later-stage BGA welding spot structure parameter optimization design.

Description

technical field [0001] The invention relates to the technical field of packaging of electronic components, in particular to a BGA solder joint structural parameter optimization method for reducing power cycle stress. Background technique [0002] Ball Grid Array (BGA) devices have been widely used in various electronic products due to their advantages of large number of pins, high yield, superior electrical performance and good heat dissipation. When BGA devices are actually used, there are alternating cycles of power-on (on), running, standby, and power-off (off). Such a cycle process is a typical power cycle process. Therefore, BGA devices In actual work, it is under a power cycle loading condition. During the power cycle process, the BGA device generates temperature rise due to the consumption of electric power, and there is a difference in thermal expansion coefficient between the BGA device body and the printed circuit board (PCB). Under the condition of power cycle te...

AI Technical Summary

Problems solved by technology

During the power cycle process, the BGA device generates temperature rise due to the consumption of electric power, and there is a difference in thermal expansion coefficient between the BGA device body and the printed circuit board (PCB). Under the condition of power cycle temperature rise, such thermal expansion Coefficient mismatch will lead to inevitable thermal stress on the BGA solder joints that are connected between the device body and the PCB, which will lead to reliability problems

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