Solder Joints Reliability Assessment for Stacked CSP Module Based on Flexible Circuit Printed Board
Solder reliability assessments for stacked CSP module based on flexible printed circuit board (FPC) are performed in this research using a 3D global model with constraint equation and two levels submodeling technique. 3D global model with constraint equation(CE) was used to provide real boundary contiditons for 1st level submodeling,and quarter local model used as 2nd level submodeling was used to address cirtical solder joint failure locations ,to estimate solder reliability for the module and to provide reasonable boundary contiditons for 2nd level submodeling.slice model used as 2nd level submodeling was used to study that the effect on the cirtical solder damage parameter under various basefilm material of FPC and geometrical parameters. It is found that thinner CSP die thickness and thinner PCB ,thicker FPC basefilm and FPC adhesive thickness and CSP thickness,and higher solder standoff height, lead to smaller averaged accumulated viscoplastic strain energy density(ΔWavg) and higher fatigue life; It is also figures out,PI and PEN basefilm material lead to smaller ΔWavg and higher fatigue life for the most critical solder than LCP material.Weibull distributions and weibull probaility density function for the module under various FPC baseflim material were obtained,and 63.2% solder joints failure life was used as solder joints reliability assessment for stacked CSP module.
Zhengyi Jiang, Shanqing Li, Jianmin Zeng, Xiaoping Liao and Daoguo Yang
H. D. Yan et al., "Solder Joints Reliability Assessment for Stacked CSP Module Based on Flexible Circuit Printed Board", Advanced Materials Research, Vols. 189-193, pp. 2125-2128, 2011