Study On The Influence Of Key Process Parameters Of The Huaxi Solid Crystal In Power Packaging Chip

As an important part of the power packaging process,the power chip welding process is an important guarantee for the development of the power module in the direction of high integration.At present,the reflow soldering process is mainly used in power chip welding,and the defects of bridge connection and standing tablet in the reflow soldering process lead to poor welding quality of the solder layer,which forces the exploration of new welding technology to solve the problem of poor welding quality of the solder layer.In this paper,the huaxi solid crystal process for chip welding is proposed,and the influence of the key process parameters of the huaxi on the quality of the chip solder layer is explored through experiment and simulation.Orthogotest and grey correlation method are used to optimize and verify the solid crystal process parameters.The specific contents and conclusions of the study are as follows:（1）The influence of solid crystal process parameters on the voids in the solder layer of the chip is studied.Build the experimental platform,based on the control variable method and X-ray detection technology to carry out chip welding experiment and detection.The experimental results show that the key process parameters are nitrogen and hydrogen protective gas,the temperature of huaxi,and the pulse number of huaxi speed.When using the H₂:N₂=1:10 ratio,when the oxygen content is 2.5ppm,the quality of the chip solder layer is good;when the temperature of huaxi is less than 277℃,the void rate of the solder layer decreases with the increase of the temperature of huaxi;when the temperature of huaxi is higher than 277℃,the void rate of the solder layer increases with the increase of the temperature of huaxi;when the speed pulse number is 1400000,the chip solder layer voids influence law is consistent with t the temperature of huaxi influence law.（2）The correlation between void rate and heat transfer quality is verified based on the huaxi experiment and simulation.Draw the fitting surface of the void rate and the actual temperature of the experimental sample respectively for comparative analysis,and establish a model for simulation analysis according to the actual void rate of the solder layer of the huaxi sample.The analysis of experimental data and simulation data shows that in the actual experiment,the sample temperature increases with the increase of void rate,on the contrary,it decreases synchronously,indicating that the process parameters of the huaxi solid crystal affect the voids in the solder layer of the chip.Thus indirectly affect the heat transfer quality of the chip solder layer.In the simulation analysis,the curve trend of the simulation temperature of the huaxi sample is consistent with that of the actual experimental temperature,and the difference between them is less than 1℃,indicating that the heat transfer quality of the solder layer of the chip changes due to the change of the size and position of the voids in the bonding layer.（3）Optimize and verify the process parameters of the huaxi solid crystal,and summarize the advantages of the huaxi solid crystal process.The process parameters were optimized and verified by orthogonal test and grey correlation method,and the reflow welding process and the huaxi process data were compared in the experiment.The data analysis shows that through the range analysis of the orthogonal test,it is pointed out that the influence of experimental factors on the void rate is as follows:the temperature of huaxi>oxygen content>the pulse number of huaxi speed.The analysis of variance shows that the effect of the temperature of huaxi on the quality of the chip solder layer is significant,and the void rate of the chip solder layer optimized by the orthogonal test is 1.8%.Based on the optimization of the grey correlation method based on the orthogonal test,the optimized void rate of the chip solder layer is 1.6%,and the optimization of the voids in the solder layer by the grey correlation method has been improved to some extent.The artificial prefabricated cavity method is used for the reflow welding process.Through the comparison of the results of the two process data,it is concluded that the best parameters of the huaxi solid crystal process will make the void rate smaller and more dispersed.The advantage of the huaxi solid crystal process is that the solder layer can be fully exposed in the cavity before the chip is bonded so that the additives and organic compounds in the solder layer can be volatilized more fully and faster.In this paper,the influence of the huaxi solid crystal process parameters on the quality of the chip solder layer is deeply studied,and the research results have a good guiding significance for the production and application of power chip the huaxi solid crystal.