New defect detection approach using near electromagnetic field probing of high density PCBAs

Abstract

With the density increase of today's printed circuit board assemblies (PCBA), the electronic fault detection methods reached their limits. In the same time the requirements of high reliability and robustness are greater. Industrials are obliged to find better-adapted test methods. Current test methods must be rethought to include a large panel of physical phenomena that can be used to detect electrical defects of components, absence, wrong value, and shorts at component level on the board under test (BUT).We will present the possibility of using electromagnetic signature to diagnose faulty components contactlessly. The technique consists in using magnetic field probes, which detect the field distribution over powered sensitive components. Reference EM signatures are extracted from a fault-free circuit, which will be compared to those extracted from a sample PCBA in which we introduced a component level defect by removing or changing the value of critical components to evaluate the relevance of the method.