Advanced printing, structuring, and lamination technologies allow for large-scale and cost-effective manufacturing of multi-layered ceramic micro devices with complex three-dimensional (3D) structures. Infrared (IR) optical coherence tomography (OCT) is a promising technology for rapid, non-contact, high-resolution, and 3D inspection of the microchannels, metal prints, defects, and delaminations embedded in alumina and zirconia ceramic layers at hundreds of micrometres beneath surfaces. In this study the recent progresses of OCT technology for ceramic materials are reviewed, and its advantages and limitations as a metrology tool are evaluated through experiments and Monte Carlo simulations. Several measurement errors of OCT are revealed and the measurement in lateral directions is significantly affected by scattering in the ceramics. Besides of that, two types of image artefacts are found to be present in OCT images due to multiple reflections between neighbouring boundaries and inhomogeneity of refractive index. A wavefront aberration exists in the OCT system with a scanning scheme of two galvo mirrors.
QC 20150512