The study of nanometre surface metrology is becoming more and more commonplace in industrial and research environments. Because of this expansion there are more and more technologies available for looking at the surface and due to the differences in the techniques each has its own specialist applications. Stylus profilometry, white light interferometry and confocal microscopy are common techniques used to measure surface metrology to nanometre precision. Strengths and weaknesses of each of the techniques are discussed with examples.
Optical interferometry is being used more and more to solve metrology problems. It is important in giving an insight into the properties of the top surface whether it is a processed surface or a thin film coating This paper will discuss metrology issues and ways in which to solve them using autocorrelation. Autocorrelation now commonly used to extract spatial information from surface profiles. It is suitable for looking at processing issues and identifying any periodic errors. An example showing the use of autocorrelation to solve process issues in diamond turning is shown.