Application of real-time holographic interferometry in the nondestructive inspection of electronic parts and assemblies

Abstract

Nondestructive inspection by holographic interferometry (HI) is quickly gaining acceptance in the electronics industry as a sensitive and accurate method of locating manufacturing and assembly flaws in a wide range of electronics, from individual components to assembled modules. This paper describes the specific application of real-time HI in the nondestructive analysis of circuit board heat exchangers and multiple-layer printed wiring boards to locate areas of debonding and delamination.In the application of HI, the choice of a stressing method is often as important as the choice of a specific HI technique. Methods for component stressing include thermal, vibrational, and pressure-induced stressing methods, and these are described in detail. In addition, two techniques for sensitivity enhancement, phase shift interferometry and beam tilt correction, are discussed in detail.