A Fluorinated Electronic Grade Coating which can help to Pass ANSI/ISA G3 Corrosion Test for Protecting Outdoor Electronics

Abstract

The proliferation of Artificial Intelligence (AI), big data, 5G, electric vehicles, Internet of Things (IoT), edge computing, High Performance Computing (HPC) and Electric Vehicle (EV) in recent years has necessitated the increased use of electronics. Therefore, the hardware reliability of electronics has received more attention in the industry. With prevalent environmental pollution, air quality will also directly or indirectly influence the life of electronics in indoor and outdoor applications. In general, the hardware reliability of electronics can be easily affected by corrosive gases, moisture, salts, contaminants and particulate matter, especially in outdoor environments with high sulfur-bearing gaseous contamination. Therefore, next generation electronics required not only high performance but also robustness against harsher environments. A guideline from the International Society for Automation (ISA) standard 71.04-2013 was used to classify the measured corrosion thickness of airbome contaminants into the various severity level rankings by using pure copper and silver coupon exposure. However, some end-customers have asked their Original Design Manufacturers (ODMs) provide the product for passing G2/G3 severity level compliant to 3 years, 5 years, even 10 years through accelerated corrosion methodologies in recent years. Therefore, more and more ODMs have adopted the conformal coating solution. Conformal coating is a popular solution which can protect the board and component to prevent the sulfur corrosion occurrence, especially in edge computing and outdoor infrastructure. In this research, Flower of Sulfur (FoS) testing method was adopted to validate the anti-corrosion capability of bare copper Printed Circuit Board (PCB) with different conformal coating materials, including typical silicon-based and electronic grade fluorine-based conformal coating, and also benchmarked them against the bare copper PCB without conformal coating. Besides, this corrosion test can be satisfied ANSI/ISA G3 severity level compliant to 5 years exposure. Several analytical methods were used in this research, including, Optical Microscope (OM) Inspection, Coulometric Reduction (CR), Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray spectroscopy (EDX). Finally, we found that fluorine-based conformal coating from 3MTMNovecTM has robust corrosion resistance that can enhance the specific protectively of outdoor electronics application.