TY - JOUR
T1 - Surface measurement errors using commercial scanning white light interferometers
AU - Gao, F.
AU - Leach, R. K.
AU - Petzing, J.
AU - Coupland, J. M.
PY - 2007/12/17
Y1 - 2007/12/17
N2 - This paper examines the performance of commercial scanning white light interferometers in a range of measurement tasks. A step height artefact is used to investigate the response of the instruments at a discontinuity, while gratings with sinusoidal and rectangular profiles are used to investigate the effects of surface gradient and spatial frequency. Results are compared with measurements made with tapping mode atomic force microscopy and discrepancies are discussed with reference to error mechanisms put forward in the published literature. As expected, it is found that most instruments report errors when used in regions close to a discontinuity or those with a surface gradient that is large compared to the acceptance angle of the objective lens. Amongst other findings, however, we report systematic errors that are observed when the surface gradient is considerably smaller. Although these errors are typically less than the mean wavelength, they are significant compared to the vertical resolution of the instrument and indicate that current scanning white light interferometers should be used with some caution if sub-wavelength accuracy is required.
AB - This paper examines the performance of commercial scanning white light interferometers in a range of measurement tasks. A step height artefact is used to investigate the response of the instruments at a discontinuity, while gratings with sinusoidal and rectangular profiles are used to investigate the effects of surface gradient and spatial frequency. Results are compared with measurements made with tapping mode atomic force microscopy and discrepancies are discussed with reference to error mechanisms put forward in the published literature. As expected, it is found that most instruments report errors when used in regions close to a discontinuity or those with a surface gradient that is large compared to the acceptance angle of the objective lens. Amongst other findings, however, we report systematic errors that are observed when the surface gradient is considerably smaller. Although these errors are typically less than the mean wavelength, they are significant compared to the vertical resolution of the instrument and indicate that current scanning white light interferometers should be used with some caution if sub-wavelength accuracy is required.
KW - Measurement errors
KW - Multiple scattering effect
KW - Surface roughness measurement
KW - White light interferometry
UR - http://www.scopus.com/inward/record.url?scp=38849169917&partnerID=8YFLogxK
U2 - 10.1088/0957-0233/19/1/015303
DO - 10.1088/0957-0233/19/1/015303
M3 - Article
AN - SCOPUS:38849169917
VL - 19
JO - Measurement Science and Technology
JF - Measurement Science and Technology
SN - 0957-0233
IS - 1
M1 - 015303
ER -