Interconnection Method Between Chip And PCB Based On Conductive Silica Gel And Its Effect Analysis

In this paper,the method of using conductive silica gel as interconnection material between chip and PCB is studied,and the effect of this interconnection method is comprehensively analyzed by combining experiment and practical application.In this study,two kinds of conductive silica gel were selected,namely conductive silica gel strip and conductive silica gel film.The conductive silica gel adhesive strip is provided by Guilin Hengchang Electronic Technology Co.,Ltd.its resistivity is less than 6?·cm when the deformation is more than 5% after compression,the p value ranges from 0.02 mm to0.08 mm,and the thickness is 1mm.Conductive silica gel film is ACF2685JLP150 vertical conductive adhesive produced by Hitachi company of Japan.When it is subjected to a vertical pressure of 196 ? 490 KPa,that is,two to five kilograms per square centimeter,the resistivity is as low as 4??·cm,the minimum p value is 0.15 mm,and the thickness is0.15 mm.In this study,three kinds of chips are used for the interconnection of conductive silica gel,namely power management chip MP2307,time base chip NE555 DT and digital power amplifier chip YDA138 E.Generally,the conductive silica gel is fixed by pressing,so the finite element analysis of the pressure on the conductive silica gel and the interference on the connection position is carried out by using ANSYS software,and the mathematical relationship between the pressure and the interference is analyzed.According to the pressure range of conductive silica gel,the interference range is determined.According to the specific interference,the connection form and structure of conductive silica gel are designed.After the interconnection between the chip and PCB is completed,the circuit outputs of the two interconnection modes are detected under the same circuit input.The two interconnection methods guide the electrical silica gel interconnection and solder paste interconnection,and the detection tools vary according to the detected circuit.For the voltage stabilizing circuit with power management chip MP2307,the output voltage of the circuit is detected by an electric meter;for the waveform generating circuit with time base chip NE555 DT,the wave signal output by the circuit is detected by an oscilloscope with a bandwidth of 60MHz;for the audio power amplifier circuit with digital power amplifier chip YDA138 E,the audio signal output by the circuit is detected by an oscilloscope with a bandwidth of 200 MHz Signal.The output results of the two interconnection modes are analyzed and compared.For the output results of numerical type,the intuitive list is used to compare the difference degree of the two interconnection modes.For the output results of wave signal type,MATLAB software is used to analyze and compare the difference degree of circuit output under the two interconnection modes.According to the output of the circuit,we know that the three kinds of chips using conductive silica gel as the interconnection material are in the normal working state.But according to the analysis of the circuit output difference between the two kinds of interconnection methods,the experimental analysis shows that when using conductive silica gel as the interconnection material,the signal waveform of the circuit output has transient fluctuations and small delay.After continuous power on and intermittent observation and detection of the circuit,the fluctuation and delay will not affect the normal operation of the chip and the normal operation of the circuit.Finally,based on the experimental results and practical problems,this paper discusses the effect of conductive silica gel as interconnection material between chip and PCB,and summarizes the challenges and prospects of conductive silica gel as interconnection material in the future.