Creep Characteristics Verification of FE Model for SnPb Solder

초록:본논문에서는네트워크서버용컴퓨터주기판내장착된열방열시스템지지구조물에대한유한요소모델의솔더크리프특성을검증하였다. 열방열시스템은앵커구조물로지지되며앵커구조물은솔더를이용하여인쇄회로기판에장착된다. 컴퓨터내발생하는지속적인고온환경하에서솔더의크리핑이발생하고이는궁극적으로지지구조물의파괴로이어진다. 유한요소모델은솔더에발생하는응력분석과수명예측을위해사용되며, 솔더크리프특성을모사하기위하여Anand 크리프모델을적용하였다. 모델을검증하고교정하기위하여크리프시험을수행하였다. 시험은인쇄회로기판의변형을제외한솔더변형만을측정하기위하여특별한지그를설계하여수행하였다. 크리프시험결과를유한요소해석결과와비교하여Anand 크리프모델을검증하고교정을수행하였다. 교정된유한요소모델을이용하여열방열시스템구조물의보다정확한수명예측을수행할수있다.Abstract: The heat sink system for a main board in a network server computer is built on printed circuit board byan anchor structure, mounted by eutectic SnPb solder. The solder creeping is caused by a constant hightemperature condition in the computer and it eventually makes fatal failures. The FE model is used to calculate thestress and predict the life of soldered anchor in the computer. In the model, Anand constitutive equation isemployed to simulate creep characteristics of solder. The creep test is conducted to verify and calibrate the soldermodel. A special jig is designed to mitigate the flexure of printed circuit board and to get the creep deformationof solder only in the test. Test results are compared with analysis and calibration is conducted on Anand model’sconstants. Precise life prediction of soldered anchor in creep condition can be performed by this model