Tin Whiskers in Electronics: Causes, Risks, and Prevention
Dr. Adam Klett, Director of Science at KYZEN Corporation, explains tin whiskers and their differences from dendrites. Tin whiskers are thin rod-like structures that grow from solder joints, are usually only a few microns in diameter and are visible mainly with scanning electron microscopy (SEM). Unlike dendrites, which form due to electrochemical migration in the presence of moisture and electrical bias, tin whiskers develop from internal stresses in cooling solder joints. These whiskers can cause electrical shorts and pose risks of critical failures or fires in electronic assemblies.
Dr. Adam suggests several mitigation strategies: adding lead to solder alloys (where permissible), cleaning assemblies to remove iron contamination, applying conformal coatings, and minimizing mechanical stresses like thermal cycling. While these methods can slow tin whisker growth, completely preventing them remains challenging. Dr. Adam emphasizes the importance of understanding and addressing this phenomenon in electronic manufacturing to ensure product reliability and safety.