Research On The Reliability Of Moisture Diffusion And Injection Molding Technology Of Plastic Packaging Devices

Because of its small size and low price,plastic packaging has gradually become the first choice of component packaging,and also widely used in aerospace and other fields.However,there are more and more challenges in the environmental reliability test and process manufacturing of plastic packaging devices.Few domestic scholars comprehensively consider the reliability of plastic packaging devices in the humid and hot environment and the defects of injection molding process.Therefore,this paper mainly studies the reliability of TO-252 plastic packaging device in hot and humid environment(85 ~oC/60%RH/168h),and simulates and predicts the injection molding process of TO-252 device.1.TO-252,a typical plastic sealing device,was taken as the research object.Firstly,the storage modulus and glass transition temperature(Tg)of five kinds of epoxy molding plastics were measured by DMA,and the specific heat capacity of molding plastics was measured by MDSC,then the moisture absorption experiment was designed to test the saturated humidity of molding plastics.Finally,the reliability of TO-252 under humidity sensitivity level 2(MSL2)was evaluated.The results show that:(1)the glass transition temperatures of molding plastics EK5600GHR,EK5600GH,EK5600H,GR700 and GR710are 124°C,134°C,168°C,119°C and 131°C respectively.(2)With the continuous increase of temperature,the storage modulus of the molding compound changes in a ladder like manner,and the heat capacity increases linearly with the increase of temperature.After reaching TG,the storage modulus of the molding compound decreases rapidly.(3)Among the five molding compounds,EK5600GH has the lowest saturated humidity,and EK5600H has the highest saturated humidity.(4)In the MSL2 evaluation test of TO-252 plastic packaging device,the device has delamination failure at the critical interface between the molding plastic and the lead frame.2.The moisture absorption and desorption characteristics of TO-252 packaging device in the process of moisture diffusion(85 ~oC/60%RH/168h)and moisture desorption(125 ~oC/24h)were studied.The influence of chip size,solder layer thickness,lead frame structure and epoxy molding compound on the total deformation of the dangerous contact surface caused by moisture diffusion was studied.The results show that:(1)in the process of moisture diffusion,the diffusion rate of moisture decreases gradually with the increase of time,and finally reaches the saturated state of moisture adsorption in the plastic packaging device.(2)The larger the chip size is,the smaller the total deformation of the dangerous contact surface is.The effect of solder layer thickness on the total deformation is not significant.The structural design of lead frame can greatly reduce the risk of delamination failure of plastic encapsulated devices.(3)The storage modulus of GR700 material is relatively large and its moisture absorption is relatively small.The total deformation of dangerous contact surface is the smallest after 168h of moisture absorption at 85 ~oC/60%RH,which is only five point nine six nine seven?m?3.According to the injection molding process of TO-252 device,the gate position of the device in the injection molding is analyzed by Moldflow software,the filling process of the plastic device is studied,and the warpage and gold line offset are predicted.The orthogonal experiment was designed to study the influence of process parameters on Warpage and gold wire offset of TO-252 packaging device in injection molding process,and the best process combination considering warpage and gold wire offset was explored by using comprehensive weighted scoring method.The results show that:(1)The total amount of warpage remaining after the injection molding process is 0.0357mm The impact of polymer melt on bonding wire results in 0.8168mm The offset of the bonding wire.(2)Through the analysis of range method,in order to minimize warpage deformation and gold line offset,the optimal combination of process parameters is[A3,B1,C2,D2,E1],[A1,B3,C4,D2,E4].When comprehensive warpage deformation and gold line offset are considered,the optimal combination of process parameters is[A1,B4,C2,D1,E2].