This document is the product of the IPC Electrochemical Migration (ECM) Task Group. It was drafted to provide guidance regarding how the IPC-TM-650, Method 2.6.25, Conductive Anodic Filament (CAF) Resistance test can best be used for evaluating the effects of mechanical stress, laminate material fracturing, ionic contamination, moisture content prior to press lamination, and other material processing characteristics on conductive anodic filament (CAF) resistance test method results. This CAF test method provides a proven standard for determining the risk of temperature, humidity and bias (THB) failure within rather than on the surface of printed circuit boards (PCBs), typically filament formation along the boundary between the resin and laminate reinforcement.

PURPOSE

This user guide addresses test issues regarding determining pass/fail criteria based on knowledge of three product goals:

a) What are the long term reliability requirements?

b) What is the closest spacing required for a given voltage differential?

c) What is the maximum safe voltage differential between features with a given spacing?