Advanced 3D roughness analysis for the characterization of ceramic surfaces

Abstract

Advanced processes often hinge on the ability to reproduce specific surface characteristics. While throughout the past century, the mean roughness value, also expressed as Ra has often been used as the main parameter to classify a surface's ability to retain oil and provide a functional bearing surface, the materials, processes and required functionalities of modern surfaces go far beyond that application. Superficial interfaces now often determine the ability of a consecutive layer to adhere to the substrate or, amongst others, enhance a surface's ability to exchange electrons or other elements. In many applications the surface itself enables the process the device is intended to deliver. The paper discusses various approaches to measure surface roughness, and takes a closer look at more advanced surface roughness parameters that allow the user to more accurately and precisely determine a surface's ability to function within its desired boundary conditions. We will review various technologies widely used to measure surface topographies, from the traditional stylus profilometry, to white light interferometry, confocal microscopy to optical systems that combine several of the advantages into one technology. Almost none of the surfaces functions today are based on surface properties of a single line, hence the paper will review the correlation between single line scan metrology and real 3D metrology. Acquiring 3-dimensional data provides the user with significantly more information. Any directionality of surface properties can now be evaluated by taking advantage of more advanced and complex roughness parameters that indicate for instance, anisotropies of surface preparation processes.