Low Melting Point Metal Doping Regulation Improves The Performance Of Nano-silver Interconnect

The technology of printing electronic devices through nano-imprinting technology and inkjet printing technology is collectively referred to as printing electronic technology,which has the advantages of high flexibility and high efficiency.At present,printing electronic technology is widely used in the fields of radio frequency identification and flexible devices.Metal nanoparticles are often used as conductive inks in the fabrication of interconnects by printing electronic technology.In the use,the inks need to be heated to make them conductive.However,printing electronic technology is limited because the flexible substrates are can not withstand higher heating temperatures.In this thesis,the conductive inks prepared by silver nanoparticles were doped nanoparticles with low melting points such as tin and indium to regulate the electrical conductivity of silver interconnects.The simulation results show that in the progress of sintering of silver nanoparticles the atoms on the particle surface play a important roll.This diffusion method has a relatively high efficiency in the early stage of sintering and has little relation with the sintering temperature.This result also indicates that it is difficult to achieve a relatively high conductivity at a relatively low temperature.However,the melting point of different metal particles has a relatively closely relationship with the melting point of the metal itself,among which the melting point of metal particles with low melting point is relatively low.Therefore,low temperature and high efficiency sintering is expected to be realized by combining liquid phase sintering technology.In order to verify this possibility,an experiment is carried out.In the experiment of doping tin nanoparticle,it is found that metallic tin will be oxidized in the air,which has a negative effect on the electrical conductivity of interconnect.This phenomenon was observed by means of XRD and SEM.Sintering temperature has obvious effect on the interconnect,doped tin particles of metal interconnect in different temperature also have different performance,when the sintering temperature of doping conductive performance is better than that of without samples,especially the temperature exceeds melting point of metal tin doped samples of interconnect conductive performance is better.The basic law of improving electrical conductivity of doped metal indium nanoparticles is similar to that of doping tin.In the case of sintering temperature of 200?,the resistivity of interconnect indium doped sample is half that of bulk silver,which is far better than that of undoped sample.Moreover,the electrical conductivity of the doped sample at 140? reached that of the undoped sample at 200?,that is,the sintering temperature was reduced 60? by doping indium without decreasing the electrical conductivity.XRD and SEM were used to observe the changes of the apparent morphology and particle size of the samples under different conditions,and it was verified that the doped metal with low melting point could make the pores between the metal particles smaller,and the melted liquid metal could promote the diffusion of the silver particles,so that the silver particles could grow larger.This provides an improved direction for further reducing the sintering temperature of metal nanoparticle inks.