Prediction of Impact Life Time in Solder Balls of the Board Level Flip Chips by Drop Simulations

Abstract

ARTICLE INFO ABSTRACTArticle history:Recently much research are has been done into the compositions of lead-free solders. As a result, there has been a rapid increase in the number of new compositions. In the past, the properties of these new compositions were determined and verified through drop-impact tests. However, these drop tests were expensive and it took a long time to obtain a result.The main goal of this study was to establish an analytical method capable of predicting the impact life-time of a new solder composition for board-level flip chips though the application of drop simulations using LS-DYNA. Based on the reaction load obtain with LS-DYNA, the drop-impact fracture cycles were predicted. The study was performed using a Sn-3.0Ag-0.5Cu solder (305 composition). To verify the reliability of the proposed analytical method, the results of the drop-impact tests and life-time analysis were compared, and were found to be in good agreement. Thus, the new analytical method was shown to be very useful and effective.

Prediction of the Impact Lifetime for Board-Leveled Flip Chips by Changing the Design Parameters of the Solder Balls

“…Table 5 Material properties of the PCB, chips and solder balls [7] Item Type [6] . Table 3은 칩 두께별 및 솔더볼의 크기를 나타내고 있다.…”