Calibration and correction of optical topography measuring technology
Funding: October 2011
Duration: April 2019 – April 2020
Team: Richard Leach, Rong Su, Matthew Thomas
Partners: Zygo
Modern products feature complex surface topographies, often involving high slope angles. Surface topography can be measured by a number of techniques and, thanks to their non-contact nature and potential speed when measuring 3D surfaces, optical methods are becoming popular. Coherence scanning interferometry (CSI) is a well-established optical technique for surface topography measurement. However, due to the optical set up of CSI, it has a difficult-to-predict response to surfaces with a range of slope angles. Under EPSRC funding, we have developed a theory to predict the response of CSI to surface slopes, and to be able to calibrate and correct its response to such slopes. The project will develop a software package to enable us to test the calibration and correction technique on commercial instruments, validate the theory and apply it to a number of case studies. The technique would be validated on a commercial instrument.
CSI transfer functions from the foil model