焊球正六边形排布倒装芯片的下填充毛细压研究

除了正四边形,正六边形也是倒装芯片中可行的焊球排布形式,为了预测封装倒装芯片时的下填充过程,需要精确计算毛细驱动压.在已有的焊球正四边形排布情况下平均毛细压计算方法的基础上,进一步研究了焊球正六边形排布情况下平均毛细压计算模型.通过分阶段处理,并根据质量守恒和力平衡的原则,分析了下填充过程,重点分析了填充面积和接触线跳跃量的计算,进而得到了计算平均毛细压的数学模型.通过实例验证了该模型的准确性,从而完善了倒装芯片封装工艺中的下填充流动解析模型.

Study of the Capillary Pressure of Flip-Chip Underfill with Hexagonal Solder Bump Arrangement

Besides quadrilateral,hexagon is another feasible solder bump arrangement in flip chip.To predict the underfilling process in flip-chip package,capillary driven pressure need to be calculated precisely.Based on the existing calculating method of the average capillary pressure in quadrilateral bump arrangement,the calculated model of the average capillary pressure in hexagonal arrangement was further studied.Through stages processing,according to the conservation of mass and the principle of force balance,the underfilling process was analyzed,the filling area and the contact line jump value were analyzed,and the mathematical model for calculating the average capillary pressure was obtained.The accuracy of the model was verified by the numerical simulation,the analytic model of the underfilling flow in flip-chip packaging process was improved.