DEVELOPMENT OF A RISK PROFILE FROM FLUX RESIDUES TRAPPED UNDER LEADLESS COMPONENTS

摘要

Electronic assemblies are more complex due to the use of miniaturized components and the increased density of circuitry placed in tighter geometries. Leadless components have extremely low standoff clearances. Flux residues can fill the underside of the component. If not properly out gassed, the residue can be wet, pliable and active. The residue, even when using a No-Clean solder paste, can cause leakage currents, intermittent and hard failures. This study will present the development of non-standard test boards that are routed to enable localized Ion Chromatography and secondly, sensor traces placed under the bottom termination to test resistance levels in areas where contamination is located. The methodologies discussed in this presentation provide useful data in quantifying the risk of contamination trapped under the body of leadless components.