Near-Zero Residue High-Reliability Novel Solder Paste for Electronics

Flux residues, which remain on assembly boards after reflow, can cause electrical and mechanical connection problems that impact the long-term reliability performance of solder joints. Near-zero residue (NZR) soldering technology, using an active reducing atmosphere such as formic gas or hydrogen, has been known for many years and is becoming an active area of research. High-reliability novel lead-free solder alloy 90.6Sn3.2Ag0.7Cu5.5Sb, designated as Indalloy®276, is known for its high reliability with wide service temperature capabilities. Indalloy®276 preforms are applied to specific applications in semiconductor industry that require high reliability and no residue. However, preforms can’t achieve the proper tackiness to hold a component during reflow, resulting in defects such as tombstoning. In this manuscript, a novel solder paste with Indalloy®276 and a specially-designed binder was developed and tested. The soldering performance testing included printability, wetting, voids, residue content, and shear strength of the created solder joints. These tests were conducted and compared with regular no-clean Indalloy®276 solder paste.