Linear finite element stress simulation of solder joints on 225 I/O plastic BGA package under thermal cycling

Abstract
Linear steady state finite element models have been performed to simulate thermally induced stresses on 225 I/O plastic ball grid array (PBGA) packages under thermal cycling (TC) condition. Eutectic solder joints (63%Sn, 37%Pb) in shapes of barrel and hourglass have been studied. The effects of thermally induced stresses on the solder joints between BT (Bismaleimide Triazine) substrate of PBGA and FR-4 print circuit board (PCB) are studied as a function of four parameters: (a) coefficient of thermal expansion (CTE) of molding compound, (b) height of solder joint, (c) size of solder pad, and (d) location of silicon chip. Furthermore, the warpages of a PBGA substrate caused by transfer molding and solder reflow processes are discussed. Several PBGA designs with minimum thermal stress are proposed based on the above finite element analysis results.

This publication has 5 references indexed in Scilit: