Reliability Evaluations of Pb-Free Solder Joint Formed Using Sn-Ag-Cu Solder Ball and Sn-Bi-Ag Solder Paste

초록

Sn-3.0Ag-0.5Cu (SAC305) Pb-free solder has been widely used in electronic packaging for its excellent mechanical and electrical properties. However, its relatively high melting temperature (217° C) can induce substrate warpage and reliability during bonding processes. To solve this, low-temperature P b-free solders with S n - B i based lower bonding temperature have been gotten attentions. However, They have a fatal weakness with the brittleness of Bi which can degrade properties of solder joints. Therefore, we studied a combined solder joint with SAC305 solder ball and Sn-57Bi-1Ag solder paste using various bonding methods. We also researched joint properties, such as the Bi diffusion and intermetallic compound (IMC) thickness, and the shear strength during isothermal aging to improve solder joint reliability.

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