Abstract A new submicron-order dimensional measurement system using a two-laser-beam scanning method and measurement results are described. Two fine spot beams, slightly separated, which are generated from an acoustoopic deflector, are scanned at 0.02 μm steps on an object by driving a signal which has two frequency components. The synthetic light intensity distribution of the two beams is adjusted to a particular distribution according to the dimension to be measured by varying that of the frequency. The shape of the reflected light intensity signal is adjusted to the particular U-shaped signal by controlling the synthetic light intensity distribution. From the value of the frequency which controls the U-shaped signal, the submicron dimentions can be measured with accuracies of ±0.02 μm.
[1]
T Wilson,et al.
Scanning optical microscopy
,
2020,
Advances in Imaging and Electron Physics.
[2]
C W See,et al.
Scanning differential phase contrast optical microscope: application to surface studies.
,
1985,
Applied optics.
[3]
R. Adler,et al.
Interaction between light and sound
,
1967,
IEEE Spectrum.
[4]
G E Sommargren,et al.
Optical heterodyne profilometry.
,
1981,
Applied optics.
[5]
N. A. Massie,et al.
Real-time digital heterodyne interferometry: a system.
,
1980,
Applied optics.