Electrochemical Migration - How Field Failures Occur and How To Avoid Them

摘要

Electrochemical migration (ECM) is an important topic in terms of the reliability and life span of electronic components, and is repeatedly discussed as the possible trigger for field failures. Due to the ever increasing requirements in terms of greater packing densities/miniaturisation as well as external environmental influences, focus is being placed on field failures triggered by humidity or impurities, particularly in components that are exposed to changing environmental influences. Examples of this are the automotive, aviation and telecommunications industries that serve a global sales market while having to ensure the electronic components functionality is maintained in each climate zone when subject to high temperature fluctuations and extreme humidity. How does electrochemical migration occur? How can the risks be assessed and, most importantly, how can it be avoided? In practice, coating processes are frequently assumed to be a complete solution. The subject of the cleanliness of components is also discussed. But in order to provide a specific answer for individual cases, it is important to understand the details of the underlying processes. The first part of this article explains the conditions and generation mechanism of electrochemical migration, the difference compared to other dendritic failures, and also addresses its consequences. The second part of the article discusses the various methods of preventing and avoiding field failures.