No-Clean Flux Residue and Reliability - An EMS Perspective
Authors: Jennifer Nguyen, David Geiger, Dennis Willie, and Murad Kurwa Company: Flextronics International Date Published: 10/14/2012
Abstract: Majority of products are built using no clean process today. Low residue is the more appropriate nomenclature however no-clean is what is commonly referred to by the engineering community. No-clean doesn’t mean that no residue is left on the assembly after the process. It means that there will be some residues which should be non-detrimental to the printed circuit assembly. Flux residues left on no-clean products can create concern with the potential risk of leakage current, electrochemical migration, and dendrite growth which could impact the long term reliability of the product. The paper will discuss an EMS perspective on no-clean flux residue reliability. It describes the tests that are done in the material evaluation and process development to mitigate the reliability risk of no-clean flux residues. It also explores the challenges that we have with the SIR test procedure and the acceptance criteria of no-clean flux residues.
no-clean, flux residue, contamination, SIR testing, reliability