Material Analysis
Crystallographic characterization techniques identify the orientation and boundary distribution of microscopic metal grains in electronics. Performing EBSD grain mapping allows engineers to examine the localized crystal structure of plated copper within microvias and solder joints. The scanning approach measures the backscattered electron diffraction patterns produced in a scanning electron microscope.
Visualizing these diffraction bands reveals the orientation gradients, grain boundary types, and texture of the deposited metal.
Electron Diffraction
Angle-dependent scattering of high-energy electrons against the crystal lattice generates bands of varying intensity on a phosphorus screen. During EBSD grain mapping, the incident electron beam scans across the highly polished cross-section of the specimen. Advanced software translates the resulting Kikuchi lines into a complete spatial map of crystal orientations.
This process exposes the presence of twin boundaries, grain size distribution, and localized strain within the copper layer. Fabricators use the grain structural information to evaluate the effectiveness of annealing steps and plating additives.
Microstructure Control
Optimizing the grain size prevents mechanical fatigue and trace cracking under cyclic thermal load. Fine and randomly oriented grains offer better resistance to fatigue compared to large, column-shaped crystal structures. Utilizing this diffraction analysis ensures that plating chemistry and heat treatments generate stable metal structures.
