Setup of a high-precision profilometer and comparison of tactile and optical measurements of standards

Abstract

Both optical and tactile probes are often used in dimensional metrology applications, especially for roughness, form, thickness and surface profile measurements. To perform such kinds of measurements with a nanometre-level of accuracy (∼30 nm), Laboratoire National de Métrologie et d’Essais (LNE) has developed a new high-precision machine. The architecture of the machine contains a short and stable metrology frame dissociated from the supporting frame. It perfectly respects the Abbe principle. The metrology loop supports reference laser interferometers and is equipped either with an optical probe or a tactile probe of nanometric resolution and linear residuals. The machine allows in situ calibration of the measuring optical and tactile probes by comparison to the laser interferometer measurements, considered as a reference. In this paper, both architecture and operation of the LNE's high-precision profilometer are detailed. A brief comparison of the behaviour (linear residuals) of the confocal chromatic and tactile probes is presented. Optical and tactile scanning of V-grooves artefacts with 75, 24, 7.5, 2.4, 0.75 and 0.24 µm depths are illustrated and discussed. In addition, a comparison between optical, tactile and atomic force microscopy measurements on a VLSI SHS 880-QC is also performed. Finally, a comparison of an optical and tactile scanning of optical aspherical lens with a polymer coating is presented and discussed.

Calibration and verification of areal surface texture measuring instruments

“…5 shows the instrument at PTB. LNE also have a primary instrument that uses laser interferometry with a linear ball-screw bearing and stylus and optical probes [139] (see Fig. 6).…”

Miniature silicon Michelson interferometer characterization for dimensional metrology

“…To inspect the effect of roughness, three aluminum test objects have been selected, with the a 10-point mean roughness parameter Rz (ISO4287:1997) of: R1 = Rz = 0.02 m (aluminum deposite) ( = 0.004 m), R2 = Rz = 2.5 m ( = 0.06 m) and R3 = Rz = 4.5 m ( = 0.15 m), measured using the LNE ultra-high precision profilometer that is traceable to the SI meter definition [21]. The recorded residual errors were found to be proportional to the roughness of the aluminum surface as shown in Fig.…”

Ultra-high precision CMMs and their associated tactile or/and optical scanning probes

“…Two type of probes can be used: optical and tactile probes. Usually tactile probes allow more accurate measurement then optical probes [8]. However, with technology progress, some industrial companies and NMIs succeeded developing new optical probes able to ensure measurements at the nanometre level of accuracy with high acquisition frequency (very short time) [9,10].…”

“…The z-laser interferometer is fixed on the supporting structure. Each laser interferometer is fixed to an intermediary positioning mechanism (two translations and one rotation) in order to adjust the alignment of the laser beam to each respective mirror [8].…”