Study on the Board-level SMT Assembly and Solder Joint Reliability of Different QFN Packages

The current paper deals with firstly the optimized SMT to assemble various types of QFN (Quad Flat Non- leaded) packages. The important SMT factors such as solder pad and stencil designs will be discussed. Secondly and more importantly, this paper will detail the comprehensive experiment and simulation work done for QFN solder joint reliability modeling. A curve fitted fatigue correlation model together with the use of Schubert's hyperbolic sine lead-free solder constitutive model will be proposed for accurate QFN solder joint reliability prediction.