Surface profiling of micro-scale structures using partial differential equations

Micromoulding is a technology capable of mass producing components with micro and nano scale surface features. The production process can be sensitive to a number of variables that can modify the complex three-dimensional surface geometry of the components. The surface is often a crucial determinant of the product’s functionality and therefore must be subject to strict quality control. Surface measurement techniques such as White Light Interferometry (WLI) generate data in the form of Cartesian point clouds, which are generally large and somewhat unmanageable. Thus, new methods for characterizing efficiently the surfaces associated with these data sets will result in better controlled product quality. Here, we propose a surface characterization technique based on the use of Partial Differential Equations (PDEs). This method characterizes the outer surface contours obtained from raw measurement data. The aim of this technique is to identify parameters providing a good description of the surface profile of a micromoulded product. The measured set of parameters is compared against the theoretical values associated with an ideal surface profile, usually that of the mould cavity, potentially providing a means of quality assessment.