Testing method for measuring corrosion resistance of surface mount chip resistors

Abstract

Surface mount chip resistors are amongst the simplest and most inexpensive of all components used in electronic circuits and systems. Typically, resistor failure modes include open circuits, resistive shorts or variations in resistance indicating parametric drift or intermittent failure, which in some applications result in overall system failure. Corrosion is currently believed to be the number one failure mechanism for chip resistors deployed in developing markets such as Central and Latin America, Asia, India and Pacific regions where aggressive corrosive conditions are prevalent. The objective of this study is to develop a test to identify or screen out corrosion-susceptible parts. Ten precision chip resistors types representative of resistors in contemporary printed circuit board assemblies are subjected to a well-defined multi-stress screen which comprises thermal cycling and mixed flowing gas exposure. The combination of thermal cycling and corrosive gas exposure is shown to provide an acceptable acceleration test to identify corrosion-susceptible parts by replicating field failures. Currently, no other test method exists which is capable of replicating field failures.

Effects of Gaseous and Particulate Contaminants on Information Technology Equipment Reliability—A Review

“…While the MFG test can sufficiently replicate surface finish failure rates, it has failed to do so in distinguishing the corrosion resistance level of surface mount thick chip resistors. The FoS technology, thus, has gained a Transactions of the ASME significant interest to establish the susceptibility chip resistors to corrosion due to attack from atmospheric sulfur in inner electrodes leading to failure [129].…”

Detection of Corrosion in Thick Film Resistors by X-Ray Imaging

“…Many different corrosion tests have been utilized to investigate the behaviour between the thick film resistor and the corrosive sulphur. Typical corrosion tests to have been used are single gas [9][10][11] and flowers of sulphur (FoS) [11][12][13] tests. In single gas tests, the thick film resistors are exposed to a high level of hydrogen sulphur (H 2 S) or sulphur dioxide (SO 2 ) with high temperature and high humidity.…”

“…One of the major drawbacks with this analysis method is that it is destructive, and, therefore, the propagation of the corrosion in a thick film resistor has not been properly investigated. Also, in previous studies [9][10][11][12] optical and scanning electron microscopy imaging methods have been utilized for analysing the corrosion on the surface of a thick film resistor. The drawback with these imaging techniques is that the underlying corroded silver layer is not visible, and the magnitude of the corrosion has not been fully determined.…”