A novel vapor pressure transfusion model for the popcorning analysis of Quad Flat No-lead (QFN) packages

摘要: Vapor pressure is caused by moisture vaporizing during the reflow heating process. Most existing models evaluate vapor based on diffusion in solids adopting Fick's law. Differing from traditional ones, a novel transfusion model proposed this paper with consideration of encapsulation molding compound into crack opening zone. Quad Flat No-lead package employed for demonstration. Based certain assumptions that can be justified through physical conditions, simple 1-D transport established and “moisture convection coefficient” defined. With convection” boundary condition, analytical solution derived. In addition to simulation, an experimental study same type also performed validation. Compared experiment results, it found strain energy release rate calculated current more reasonable than those models. Several key features comparison between are discussed paper.