Mechanical Shock Durability Studies of Sn-Ag-Cu-Ni BGA Solder Joints on Electroless Ni-P/Au Surface Finish

Abstract

In this study, 60 solder compositions were examined in an effort to improve the integrity against impact loads of the solder joints on an electroless Ni-P/Au surface finish. The Ag, Cu, and Ni contents in the Sn-based solder varied from 0 to 4.5 wt%, 0 to 2.0 wt%, and 0 to 0.05 wt%, respectively. Impact shear tests were performed to investigate solder joint integrity after solder ball reflowing, after reflow soldering twice more, after storage at room temperature for 168 hours, and after storage at 150°C for 1,000 hours. According to the results, the Ag content should be as low as possible, the Cu content should be from 0.5 to 0.7 wt%, and the Ni content should be as high as possible. The Ag and Ni contents should be determined in consideration of the wettability and the board-level reliability of the solder joints.

Evaluation of Absorbed Impact Energy of Sn-3.0Ag-0.5Cu (-xCo) Solder Joints with Co-P Plating a Using Ball Impact Test

“…Because of their ease of implementation, ball impact tests have been widely adopted in assessing the reliability of the solder joints. [2,[5][6][7][8] Morita et al proposed a miniature impact test to evaluate impact reliability by adopting the principle of the classic Charpy impact test. [9] This test has been used by various researchers to evaluate impact reliability.…”