Definition

Conductive Anodic Filament (CAF) is an electrochemical migration failure where copper ions migrate along the glass fiber/resin interface under voltage bias and humidity, eventually forming a conductive path causing shorts. CAF growth requires voltage, humidity, and a vulnerable path (poor fiber-resin adhesion). Risk factors include high voltage, fine pitch (closer spacing), and poor laminate quality. CAF-resistant laminates use improved glass treatments and resin systems. Testing per IPC-TM-650 evaluates CAF resistance. High-reliability designs specify CAF-resistant materials.