Solder flux chemistry and climatic reliability of electronics: optimization of flux chemistry for robust performance 

 PhD student: Feng Li

This PhD project is a part of the CreCon Industrial consortium on “Climatically reliable electronics”. Overall aim of the PhD project is to build deep scientific understanding on various parts of solder flux chemistry and combinations of flux components on humidity related reliability issues of electronics with the goal of using the knowledge for making robust flux systems satisfying both climatic reliability and soldering requirements. Overall objective is to develop feasible methods rooted in scientific concepts for making optimized flux chemistry formulations better than the one existing today. Work involves investigation new humidity benign flux activators and finding the effect on humidity robustness when used for electronics, model flux systems and humidity behaviour, understanding soldering related factors, effect on conformal coating etc. Another aspect of the project is understanding the reflow flux residue and humidity interaction. Humidity influence reflow residue by changing the residue morphology. Change in residue morphology leads to release of active components that can cause humidity robustness issues for example related to BGA component. Reflow flux residue and its humidity interaction has been comprehensively investigated in this project including the effect of paste chemistry, component standoff height, thermal effects, humidity exposure and time etc.

Project is in collaboration with CreCon Consortium Industrial partners: Danfoss, Vestas Wind Systems, Grundfos, Widex, Eltek, Volvo, Inventec, Wevo. Key industrial partner for the project is Inventec, France.

Contamination assisted water film formation on a PCBA under humid condition, which can leads to leak current failures, ECM, or other failure modes

Source of Funding:

CELCORR/CreCon Industrial consortium
 Industrial collaborators:
Danfoss, Grundfos, Vestas, Eltek, Widex, Inventec, Wevo, Volvo