Research On Nano-silver Sintering Technology For Power Devices

Low temperature sintering of nano-silver is a promising interconnection technology.As a green non-polluting material,nano-silver has low sintering temperature,high melting point,good electrical conductivity,thermal conductivity and many other excellent properties.It has attracted extensive attention of the industry in the field of power electronic packaging and is an ideal connecting material in the field of high-power electronic packaging.So far,a great deal of research has been done on nano-silver,and the feasibility of nano-silver used in high-power electronic components connection has been verified by various experiments,but it has not been applied in the field of aerospace engineering.Therefore,the research on the application of low-temperature sintering nano-silver technology in aerospace electronic products has great scientific research value and national defense construction value.In order to realize the nano-silver connection of power devices in a certain type of satellite,the sintering process parameters of nano-silver were explored,and the reliability of nano-silver was studied comprehensively through experiments and theoretical analysis.Five factors affecting the sintering quality of silver nanoparticles were summarized,including coating thickness,coating area,peak temperature,heating rate and holding time.The shear strength of the joint layer of nano-silver sintered samples was taken as the evaluation index,and the parameter ranges of each factor were obtained when the sintering quality of samples was high.In the range of parameters obtained,the reasonable values of various factors were selected and the multi-factors affecting the sintering quality were analyzed.In order to simplify the number of experiments,the orthogonal method was used to design the experimental scheme and find out the technological parameters suitable for the nano-silver sintering.Temperature cycling and constant acceleration tests were carried out,and metallographic samples before and after environmental tests were prepared.The metallographic test shows that there are very few cracks and other defects in the cross section of the sample.The shear strength test shows that the shear strength of the sample after environmental test is above 10 MPa.The percentage of voids detected by X-RAY is far less than 30%,which meets the requirement of the total void rate less than 30% of the total welding area and the single void less than 5% of the total welding area.It shows that the test scheme is feasible.