Advanced scanning acoustic technique application in flip-chip devices

Abstract

Micron-size embedded defects are challenging to detect using the traditional acoustic scanning microscope. This paper presents the latest acoustic techniques using Virtual Rescanning Mode™ (VRM) from Sonoscan® to successfully capture the defects localized at inter-layer dielectrics (ILD). Defects between copper trace and solder mask are more clearly seen when the magnitude of acoustic waveform changes from time domain to frequency domain.