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This PhD project is a part of the CreCon Industrial consortium on “Climatically reliable electronic devices”. Overall aim of the PhD project is to develop various preventive measures for humidity caused failure focusing on increasing the intrinsic reliability of Printed Circuit Board Assembly (PCBA). This include evaluation of humidity barrier coatings, PCBA processing and cleanliness aspects, PCBA – component interaction with critical corrosive conditions and coating performance, and better accelerated test method for lab-field correlations.
Present Ph.D. project will focus on in depth understanding of various strategies for enhancing the humidity robustness of PCBA based on understanding from previous projects under CreCon consortium investigating the influencing factors and mechanisms. Presently used methods such as conformal coating has serious limitations that depends on the PCBA characteristics and processing. Hence, there are many synergistic factors in combination that needs to be considered when developing the preventive measures such as PCBA design, process aspects, and application environment. Therefore, the present Phd project will focus on the following:
• Coating-PCBA interaction: Work will focus on understanding the adhesion issues as a function of PCBA material, architecture, and process aspects including the effect of cleaning after soldering process to remove hygroscopic flux residues.
• PCBA cleaning chemistry vs cleaning performance: Investigation will focus on the effect of PCBA architecture and flux chemistry on cleaning efficiency.
• Interaction between PCBA components to critical corrosive conditions: Investigations will focus on the effect of Sulphur gases together with humidity on PCBA components such as resistors (due to silver) and other components containing silver/copper with and without conformal coating. Aim will also be to develop a proper test method.
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