Research On The Applicability And Testing Technology Of Solder Paste

Solder paste plays an important role in SMT production.The quality of solder paste directly determines the welding quality.Statistics show that four fifths of welding defects are related to the selection,application and quality of solder paste.Nowadays,the electronic industry has penetrated into all walks of life.The high integration,accuracy and stability of electronic products require further performance of solder paste.Therefore,the performance of solder paste is very important.Only with good quality solder paste can surface mounting production proceed smoothly.Based on the present situation of SMT solder paste used in aerospace production units,five main types of solder paste were selected to carry out research on solder paste related technology.Firstly,the composition and preparation technology of solder paste were studied,and the reaction mechanism between the components during reflow soldering was understood.Then the performance of five solder pastes was tested.The physical and chemical properties,tin bead test,wettability test,expansion rate test,wettability angle test and collapse performance test were used to evaluate the performance of the solder paste,and the influence of each performance parameter on the welding effect was determined.Finally,the applicability between QFP,BGA,LGA and five solder pastes is studied.The solder paste types are selected for three package type according to the test results by means of VS8,X-Ray and metallographic analysis.The research of solder paste detection technology shows that the comprehensive performance of sample 4(Indium NC-51AC)of five solder paste products is the best.It is suggested that each aerospace production unit should be the preferred type of solder paste.The solder paste applicability study shows that the pin mechanical strength of QFP packaged devices is increased by more than 10% when preferring Sample 4(Indium NC-51AC).Sample 3(Alpha UP-78)and Sample 4(Indium NC-51AC)should be preferred for BGA and LGA packaged devices,and the void rate can be effectively reduced.