An Effective Accelerated Method to Verify the Creep Corrosion Failure Occurrence on Electronics

Abstract

Due to the proliferation of Information Technology (IT) equipment applications, including Artificial Intelligence (AI), Big Data, 5G, Internet of Things (IoT), Edge Computing and High Performance Computing (HPC) in recent years. Therefore, the hardware reliability of IT equipment is paid more attention in the industry. With the more and more severe environmental pollution, the air quality will also directly or indirectly influence the life of IT equipment wherever indoor and outdoor. In general, the hardware reliability of IT equipment was easily affected by corrosive gases, moisture, contaminants and particulate matter. It can potentially cause the electrical short failure due to creep corrosion occurrence on corrosion sensitive components, Print Circuit Board (PCB) and PCB Assembly (PCBA). Therefore, it is very important to verify the robustness against creep corrosion occurrence for the future electronics. Creep corrosion is a kinds of failure mode of sulfur corrosion, the typical feature of creep corrosion can be observed from PCB and leadframe packages. In environments high in sulfur-bearing gaseous contamination, the major corrosive product; cuprous sulfide (Cu 2 S) was formed due to the bare copper exposure. The solid corrosion products migrated over a surface of solder mask and molding compound without the influence of an electric field. Besides, the extent of creep corrosion may be so high as to electrically short circuit adjacent pads and traces, causing the electrics to malfunction which be known as the creep corrosion failure. Mixed Flowing-Gas (MFG) and Flower of Sulfur (FoS) were adopted widely for all suppliers in the industry. To consider that traditional testing method: MFG is expensive, long testing duration; and typical FoS testing of ASTM B809 standard is relatively inexpensive, short testing duration, but cannot verify the creep corrosion. In the light of the above, the International Electronics Manufacturing Initiative (iNEMI) has published a White Paper regarding the creep corrosion verification in August, 2018. The iNEMI project team, including the leading 3rd party testing lab for electronics verification: Integrated Service Technology (iST) and international branding system house: IBM, Lenovo, Nokia, Dow. etc. have analyzed the reason of creep corrosion occurrence and also developed a cost-effective and convenient testing method: iNEMI FoS test which is sufficiently well developed for consideration as an industry standard qualification test for creep corrosion To hope that iNEMI FoS test can assist the all suppliers to find out the prevention action and solution of creep corrosion failure occurrence in the industry. In this paper, we will present some case studies as well as solution cases by using iNEMI FoS test.