White-light interferometry on rough surfaces--measurement uncertainty caused by surface roughness

Abstract

White-light interferometry measuring an optically rough surface commonly does not resolve the lateral structure of the surface. This means that there are height differences within one resolution cell that exceed one-fourth of the wavelength of the light used. Thus the following questions arise: Which height is measured by white-light interferometry? How does the surface roughness affect the measurement uncertainty? The goal of the presented paper is to answer these questions by means of numerical simulations. Before the aforementioned questions can be answered, the distribution of the intensity of individual speckles, the influence of surface roughness, and the spectral width of the light source used are discussed.

Epoxy adhesive behaviour on ceramic surfaces in commercial optoelectronic assemblies

“…In addition there is a high frequency of missing data in the profiles, probably due to the incident light angles being such that the light is not returned to the sensor. These issues have been documented in the literature [9].…”

Measurement Uncertainty of White-Light Interferometry on Optically Rough Surfaces

“…In this work, we consider two influences that cause the measurement uncertainty: rough surface and the shot noise of the camera. The influence of rough surface on measurement uncertainty was described in our previous work (Pavlíček & Hýbl, 2008). It shows that the measurement uncertainty caused by surface roughness depends on the roughness and the intensity of individual speckle.…”

“…3. The limit beyond which the correlogram becomes distorted was found numerically (Pavlíček & Hýbl, 2008) …”

“…The coherence length l c is related to the spectral width of the light source ∆λ.Foraspectralwidth∆λ much lower than the central wavelength λ 0 of the light source, it holds (Pavlíček & Hýbl, 2008) …”

“…The goal of this work is to find the measurement uncertainty of white-light interferometry influenced by both effects. Similar to (Pavlíček & Hýbl, 2008), the calculations are performed numerically.…”