Investigation of Bi and In Elemental Addition in Solder Paste for DRAM Module Reliability Enhancement

Abstract

Solder pastes with Bi and In elemental additions were studied by solder joint strength, physical failure analysis, and module reliability tests in this work. Bi-doped solder alloys were found to have stronger solder joints than SAC305 and SnAgCu-In. During the temperature cycling test, SnAgCu-In appeared the best in thermal reliability performance. Samples with Bi and without Bi were observed with different crack modes: trace cracks were found in Bi-doped, and fatigue cracks existed in samples without Bi.