3D Micro-Metrology Using a Nanofocus X-Ray Source

Metrology applied to microsystems accelerates yield improvement and sustains performance at all stages of processing thereby ensuring manufacturability. One measure of the manufactured part quality in micro-structures, e.g., microfluidic channels or LIGA-fabricated parts and assemblies, is the side-wall verticality and/or curvature. In this paper, we report on initial investigations to directly obtain three-dimensional metrological information with micron-scale spatial resolution. Using a lab-based nanofocus x-ray source (0.5 micron spot size), samples a few millimeters in diameter can be examined with high volumetric resolution by collecting thousands of (tomographic) projections. Following reconstruction of the projection data, dimensional information is extracted directly from the object’s 3D rendering. A test part was used to verify and optimize the tomographic inspection process, and the application of this method to a LIGA-fabricated part is presented.Copyright © 2005 by ASME